Composite member and production method for same

Abstract

Provided is a composite member that has a high-strength insulating coating film formed at a desired region of the surface of a substrate and can thereby prevent reductions in insulating properties caused by partial damage to an insulating coating film. A composite member (20) includes a substrate (25) and an insulating coating film (10) that covers at least a portion of the surface of the substrate (25). The substrate (25) has a first region (41) and a second region (42) that have different surface roughnesses. The surface roughness Ra1 of the first region (41) is at least 1 μm, and the ratio (Ra1 / Ra2) of the surface roughness Ra1 of the first region (41) to the surface roughness Ra2 of the second region (42) is 1.5–60.

Description

Composite member and manufacturing method thereof

[0001] The present invention relates to a composite member in which a substrate is coated with an insulating coating, and a method for producing the same.

[0002] Various electronic devices, electric vehicles (EVs) driven by electric motors, hybrid vehicles, storage batteries, etc. are equipped with power storage devices in which multiple battery cells are connected in series or parallel via bus bars. Furthermore, lithium-ion secondary batteries, which are capable of higher capacity and output than lead-acid batteries or nickel-metal hydride batteries, are mainly used as battery cells.

[0003] Bus bars are required to have insulating properties to prevent fires and equipment failures caused by short circuits. For example, Patent Document 1 discloses a bus bar used to electrically connect a battery module to other external devices. The bus bar described in Patent Document 1 has mounting holes formed at both ends of an aluminum body, and the outer surface of the body is covered with an insulating layer formed by dipping insulation processing.

[0004] Chinese Utility Model No. 218731641

[0005] However, when an insulating layer is formed by dipping, as in the busbar described in Patent Document 1, the insulating layer becomes thinner, for example, at corners, making the corners prone to insulation failure. Furthermore, to improve the insulation at the corners, the insulating layer needs to be made thicker overall. Therefore, the amount of paint used to form a thick insulating layer increases, resulting in increased manufacturing costs. Note that insulating coatings are formed on portions of the surfaces of components that require electrical conductivity, not limited to busbars. However, there are a wide variety of regions that require high insulation and strength. For example, if there is a high probability that another component will come into contact with a specific region on the plane of a conductive component, the insulating layer in that region is likely to peel off. For this reason, an insulating layer with excellent strength may be required in a specific region.

[0006] The present invention has been made in consideration of the above problems, and aims to provide a composite member in which a high-strength insulating coating is formed in a desired region on the surface of a substrate, thereby preventing a decrease in insulating properties due to partial damage to the insulating coating. Another aim of the present invention is to provide a method for producing a composite member having the above insulating coating easily and at low cost.

[0007] The above object of the present invention is achieved by the following configuration [1] relating to a composite member.

[0008] [1] A composite member having a substrate and an insulating coating covering at least a portion of the surface of the substrate, wherein the substrate has a first region and a second region having different surface roughnesses, the surface roughness Ra1 of the first region is 1 μm or more, and the ratio (Ra1 / Ra2) of the surface roughness Ra1 of the first region to the surface roughness Ra2 of the second region is 1.5 or more and 60 or less.

[0009] Furthermore, preferred embodiments of the present invention relating to the composite member relate to the following [2] to

[11] .

[0010] [2] The composite member according to [1], wherein a ratio (T1 / T2) of a thickness T1 of the insulating coating formed in the first region to a thickness T2 of the insulating coating formed in the second region is 1.05 or more and 2 or less.

[0011] [3] The composite material according to [1] or [2], characterized in that the base material has a pair of opposing main surface portions, a plurality of end surface portions connecting the pair of opposing main surface portions, and corner portions between the main surface portions and the end surface portions, the first region includes at least a part of the corner portions, and the second region is a region excluding the first region and includes at least a part of the main surface portions.

[0012] [4] The composite member according to [3], wherein a ratio (T3 / T4) of a thickness T3 of the insulating coating formed on the corner portion in the first region to a thickness T4 of the insulating coating formed on the main surface portion in the second region is 0.1 or more and 2 or less.

[0013] [5] The composite material according to [4], characterized in that the thickness T3 is 150 μm or more.

[0014] [6] The composite member according to any one of [3] to [5], wherein the first region includes at least a part of the end surface portion.

[0015] [7] The composite member according to any one of [1] to [6], characterized in that the insulating coating has a matrix containing a compound having a siloxane bond and an inorganic material dispersed in the matrix.

[0016] [8] The composite member according to [7], characterized in that at least a part of the surface of the insulating coating has a resin layer containing a resin different from the material of the matrix.

[0017] [9] The composite material according to [7] or [8], wherein the compound having a siloxane bond is at least one of silicone and silica sol.

[0018]

[10] The composite member according to any one of [1] to [9], which is applied to a bus bar that connects a plurality of battery cells or battery modules.

[0019]

[11] The composite member according to any one of [1] to [9], which is applied to a connector, a protective part for a battery module, a case for an electronic component, a battery cell, a battery module, a battery pack, or a motor coil.

[0020] The above object of the present invention is achieved by the following configuration

[12] relating to a method for producing a composite member.

[0021]

[12] A method for manufacturing a composite member according to any one of [1] to

[11] , comprising: a blasting process for blasting at least a portion of the surface of the base material to form the first region having a surface roughness Ra1 of 1 μm or more; a coating process for coating at least a portion of the surface of the base material with a first coating material so as to include at least a portion of the first region; and a first coating material hardening process for hardening the first coating material, characterized in that the insulating coating containing the first coating material is formed on at least a portion of the surface of the base material.

[0022] Furthermore, preferred embodiments of the present invention relating to a method for manufacturing a composite member relate to the following

[13] to

[24] .

[0023]

[13] The method for producing a composite member according to

[12] , wherein the first coating material includes a matrix material containing a compound having a siloxane bond and an inorganic material.

[0024]

[14] The method for producing a composite member according to

[13] , wherein the compound having a siloxane bond contained in the first coating material is at least one of silicone and silica sol.

[0025]

[15] The method for producing a composite member according to any one of

[12] to

[14] , wherein the substrate has a pair of opposing main surface portions, a plurality of end surface portions connecting the pair of opposing main surface portions, and corner portions between the main surface portions and the end surface portions, and wherein in the blasting treatment step, an abrasive is projected onto an area including at least a part of the corner portions.

[0026]

[16] The method for producing a composite member according to

[15] , characterized in that in the blasting step, an abrasive is projected onto an area including at least a part of the corner and at least a part of the end face portion continuous with the corner.

[0027]

[17] The method for producing a composite member according to any one of

[12] to

[16] , wherein in the coating step, the substrate is coated with the first coating material by immersing it in the first coating material.

[0028]

[18] The method for manufacturing a composite member according to any one of

[12] to

[17] , characterized in that a first coating material drying step of drying the first coating material is provided between the deposition step and the first coating material hardening step.

[0029]

[19] The method for manufacturing a composite member according to any one of

[12] to

[18] , further comprising: a second coating material immersion step of immersing the substrate, on which a coating made of the first coating material has been formed, in a second coating material after the first coating material hardening step; and a second coating material hardening step of hardening the second coating material.

[0030]

[20] The method for manufacturing a composite member according to

[19] , characterized in that the second coating material is a material that constitutes at least a part of the insulating coating and is made of a matrix material containing a compound having a siloxane bond.

[0031]

[21] The method for producing a composite member according to

[20] , wherein the compound having a siloxane bond contained in the second coating material is at least one of silicone and silica sol.

[0032]

[22] The method for manufacturing a composite member according to any one of

[19] to

[21] , characterized in that a second coating material drying step of drying the second coating material is provided between the second coating material immersion step and the second coating material hardening step.

[0033]

[23] The method for producing a composite member according to

[15] or

[16] , wherein the insulating coating is formed so that the thickness of the insulating coating at the corners is 150 μm or more.

[0034]

[24] The method for producing a composite member according to

[13] , characterized by comprising a resin layer forming step of applying a resin material containing a resin different from the matrix material to at least a part of the surface and curing the resin material to form a resin layer.

[0035] The composite member of the present invention has a first region on the surface of the substrate, the first region having a surface roughness of 1 μm or more, and a second region having a surface roughness within a predetermined range, so that the insulating coating can be formed to a large thickness in the first region, thereby preventing a decrease in insulating properties due to partial damage to the insulating coating. Furthermore, the manufacturing method of the composite member of the present invention allows for the easy and low-cost production of a composite member having an insulating coating with the above-mentioned excellent performance, simply by performing a blast treatment on the desired region of the substrate.

[0036] FIG. 1 is a photograph, in lieu of a drawing, showing a busbar to which a composite member according to this embodiment is applied. FIG. 2 is a schematic diagram showing an enlarged portion of a cross section taken along line A-A of the composite member according to the first embodiment. FIG. 3 is a photograph, in lieu of a drawing, showing a cross section of a composite member using three different types of substrates. FIG. 4A is a perspective view showing a composite member according to a second embodiment. FIG. 4B is a cross section taken along line B-B of FIG. 4A. FIG. 5A is a diagram showing the steps of a method for manufacturing a composite member according to this embodiment, and is a schematic diagram showing a blasting treatment step. FIG. 5B is a diagram showing the steps of a method for manufacturing a composite member according to this embodiment, and is a schematic diagram showing a deposition step. FIG. 5C is a diagram showing the steps of a method for manufacturing a composite member according to this embodiment, and is a schematic diagram showing the manufactured composite member.

[0037] The present inventors have conducted extensive research to obtain a composite member in which a high-strength insulating coating is formed in a desired region without increasing manufacturing costs, thereby improving insulation properties. As a result, the present inventors have found that by adjusting the surface roughness of a desired region on the surface of a substrate, a thick and strong insulating coating can be formed only in a specific region.

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and can be implemented with any modifications within the scope of the gist of the present invention.

[0039] [Composite Member] FIG. 1 is a photograph showing a busbar to which a composite member according to this embodiment is applied. FIG. 1 also shows the state in which a composite member (busbar) 20 is attached to a battery cell 110. The composite member 20 has a substrate (busbar body) 25 and an insulating coating 10 that covers at least a portion of the surface of the substrate 25. The substrate 25, made of a conductive material, is, for example, a Z-shaped metal plate. An electrode 111 of the battery cell 110 is inserted into a connection hole 26a at one end, and a terminal cap 112 is attached to secure the substrate 25. An adjacent battery cell (not shown) or an external device (not shown) is connected to a connection hole 26b at the other end of the composite member 20.

[0040] First Embodiment Figure 2 is a schematic diagram showing an enlarged cross section of a composite member according to a first embodiment, taken along the line A-A. While the busbar is, for example, a Z-shaped plate-like member as shown in Figure 1, the present specification will describe the characteristics of a flat composite member 20 excluding the bent portion. The substrate 25 has a pair of opposing main surface portions 25a, a plurality of end surface portions 25b connecting the pair of main surface portions 25a, and corner portions 25c between the main surface portions 25a and the end surface portions 25b. The corner portions 25c have a rounded cross-sectional shape, and the outer surfaces of the insulating coatings 10 formed in the areas of the corner portions 25c also have a rounded cross-sectional shape.

[0041] The substrate 25 also has a first region 41 and a second region 42 having different surface roughnesses. In this embodiment, the end surface 25b including the corner 25c is defined as the first region 41, and the remaining region, for example, at least a portion of the main surface 25a, is defined as the second region 42. The surface roughness Ra1 of the first region 41 is 1 μm or greater. The ratio (Ra1 / Ra2) of the surface roughness Ra1 of the first region 41 to the surface roughness Ra2 of the second region 42 is set to 1.5 or greater and 60 or less. Furthermore, the ratio (T3 / T4) of the thickness T3 (thickness of the corner) of the insulating coating 10 formed in the first region 41 when the first region 41 includes the corner 25c to the thickness T4 (thickness of the main surface) of the insulating coating 10 formed in the second region 42 when the second region 42 includes at least a portion of the main surface 25a is set to 0.1 or greater and 2 or less.

[0042] In the composite member according to this embodiment, the surface roughness Ra1 of the first region 41, including the corners 25c, is 1 μm or greater. Therefore, the thickness T3 of the insulating coating 10 formed on the first region 41, i.e., the thickness of the corners 25c in the first region 41, is, for example, 150 μm or greater, which is sufficient to prevent a decrease in insulation properties due to damage. Furthermore, the ratio (Ra1 / Ra2) of the surface roughness Ra1 of the first region 41 to the surface roughness Ra2 of the second region 42 is set to 1.5 or greater and 60 or less. This prevents the insulating coating 10 from being unnecessarily thick in unnecessary regions, thereby suppressing increases in material costs for the insulating coating 10. Furthermore, when the ratio (T3 / T4) of the thickness T3 of the corners 25c in the first region 41 to the thickness T4 of the main surface 25a in the second region 42 is specified as described above, the insulating coating 10 has a more controlled thickness. As a result, it is possible to obtain a composite member 20 having a high-strength insulating coating 10 in a desired region, excellent insulating properties, and reduced material costs.

[0043] Furthermore, when the composite member 20 is applied to a bus bar, the insulating coating 10 may be struck by metal fragments from a battery cell 110 that has experienced thermal runaway, fragments of the insulating coating from other bus bars, or broken pieces of the battery case. In this embodiment, the insulating coating 10 is thick at the end surfaces 25 b and corners 25 c, and the corners 25 c have a rounded surface. The outer surfaces of the insulating coating 10 at the corners 25 c also have a rounded surface. Therefore, even if flying debris or the like strikes the outer surface of the insulating coating 10, damage to the insulating coating 10 by the debris or the like can be minimized. Furthermore, because the surface of the insulating coating 10 has a rounded surface, the striking debris or the like is reflected obliquely, thereby mitigating the impact of the debris or the like on the composite member 20.

[0044] In the composite member 20 shown in FIG. 2 , the corner 25 c of the substrate 25 has a rounded cross-sectional shape. However, in the present invention, the cross-sectional shape of the corner 25 c is not particularly limited and may have a chamfered or substantially right-angled shape. However, if the cross-sectional shape of the corner 25 c is substantially right-angled, it would be difficult to form an insulating coating 10 of a desired thickness on the corner 25 c, even if the corner 25 c and its surrounding area are defined as the first region 41 and the surface roughness Ra1 is 1 μm or greater. Therefore, it is preferable that the cross-sectional shape of the corner 25 c of the substrate 25 has a rounded or chamfered cross-sectional shape. Furthermore, regardless of the shape of the corner 25 c, it is preferable that the cross-sectional shape of the insulating coating 10 formed on the corner 25 c has a rounded cross-sectional shape.

[0045] Figure 3 is a photograph showing the cross sections of composite members using three different types of substrates. Specifically, I is a composite member in which the surface roughness of the entire substrate surface is less than 1 μm, II is a composite member in which the surface roughness of the entire substrate surface is 1 μm or more, and III is the composite member 20 according to the first embodiment. That is, the composite member 20 uses a substrate in which the surface roughness Ra1 of the end surface 25b (first region 41) of the substrate 25 is 1 μm or more and the surface roughness Ra2 of at least a portion of the main surface (second region 42) is (Ra1 / 60) μm or more and (Ra1 / 1.5) or less. As shown in Figure 3, compared to I, in which the entire substrate surface is smooth, and II, in which the entire substrate surface is rough, the insulating coating 10 is formed thicker on the surface of the corner 25c of the composite member 20, and the T3 / T4 value is the largest. From these findings, it can be seen that in the composite member 20 according to the first embodiment, an unnecessary thickness of the insulating coating 10 is not formed on the main surface 25a of the substrate 25, and a thick insulating coating 10 is formed at the corners 25c of the substrate 25. Therefore, at the corners 25c where the insulating coating 10 is thin and prone to peeling, the strength of the insulating coating 10 can be improved and insulation properties can be maintained.

[0046] Second Embodiment Fig. 4A is a perspective view showing a composite member according to a second embodiment, and Fig. 4B is a cross-sectional view taken along line B-B in Fig. 4A. In the second embodiment shown in Fig. 4A and Fig. 4B, the same parts as those in the first embodiment shown in Fig. 2 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted or simplified. As in the first embodiment, the second embodiment also assumes that the composite member 50 is a flat plate-shaped member.

[0047] 4A and 4B , in the composite member 50 according to the second embodiment, a portion of the principal surface 25a is designated as a first region 51, and the first region 51 has a surface roughness Ra1 of 1 μm or greater. Meanwhile, a portion of the principal surface 25a excluding the first region 51 is designated as a second region 52, and the second region 52 has a surface roughness Ra2 such that the ratio Ra1 / Ra2 is 1.5 or greater and 60 or less. Therefore, in the composite member 50, the thickness T1 of the insulating coating 10 in the first region 51 of the principal surface 25a is greater than the thickness T2 of the insulating coating 10 in the second region 52 of the principal surface 25a.

[0048] The composite material 50 according to the second embodiment configured in this manner can also achieve the same effects as those of the first embodiment. In particular, in this embodiment, by designating the region of the main surface portion 25 a that requires high strength as the first region 51, partial peeling of the insulating coating 10 can be prevented and excellent insulation properties can be maintained even when the composite material 50 is used for a long period of time.

[0049] Next, the surface roughness Ra1 of the first regions 41 and 51 of the substrate 25, the surface roughness Ra2 of the second regions 42 and 52, and the thicknesses T1 to T4 of the insulating coating 10 formed in each region will be described in detail below.

[0050] (Surface roughness Ra1 in first regions 41, 51) In a composite member having an insulating coating, the areas where the insulating coating is likely to peel vary depending on the shape and location of use. Therefore, increasing the thickness of the insulating coating is effective in preventing peeling of the insulating coating and achieving high insulation properties. However, increasing the thickness of the insulating coating over the entire surface of the substrate increases the cost of the insulating coating material. Furthermore, applying the insulating coating material multiple times only to desired areas can increase the thickness of the insulating coating in those areas, but this increases the number of processes and therefore the manufacturing cost.

[0051] In this embodiment, the regions where a thick insulating coating 10 is desired are designated as first regions 41, 51. If the surface roughness Ra1 of the first regions 41, 51 is less than 1 μm, the insulating coating material (first coating material) will not be applied to a sufficient thickness in the manufacturing process described below, making it impossible to form a strong insulating coating in the desired region. Therefore, the surface roughness Ra1 of the first regions 41, 51 is set to 1 μm or more, preferably 1.5 μm or more, and more preferably 2 μm or more.

[0052] (Ratio of surface roughness Ra1 of the first region to surface roughness Ra2 of the second region (Ra1 / Ra2): 1.5 or more and 60 or less) Furthermore, to prevent the overall thickness of the insulating coating 10 from increasing and material costs from rising, at least a portion of the regions on the surface of the substrate 25 excluding the first regions 41, 51 are designated as second regions 42, 52. If the ratio of surface roughness Ra1 of the first region to surface roughness Ra2 of the second region (Ra1 / Ra2) is less than 1.5, the thickness of the insulating coating 10 will be too thick even in the region (second region) where the strength of the insulating coating 10 is not particularly required, resulting in increased material costs. Therefore, the ratio of surface roughness Ra1 to surface roughness Ra2 (Ra1 / Ra2) should be 1.5 or more, preferably 3 or more, and more preferably 6 or more.

[0053] On the other hand, if the ratio of surface roughness Ra1 to surface roughness Ra2 (Ra1 / Ra2) exceeds 60, the surface roughness Ra1 in the first region 41 becomes too large relative to the basic surface roughness Ra2 of the surface of the substrate 25, and the number of steps required to satisfy this condition increases. Furthermore, even if the surface roughness Ra1 is increased beyond a predetermined level, it is difficult to increase the thickness of the insulating coating applied to that region. Therefore, the ratio of surface roughness Ra1 to surface roughness Ra2 (Ra1 / Ra2) should be 60 or less, preferably 50 or less, and more preferably 40 or less.

[0054] As described above, the regions requiring high strength vary depending on the shape and location of the composite member. Therefore, the first regions 41, 51 are set in locations where a thick insulating coating 10 is desired. However, particularly in members with rectangular cross sections, corners are prone to force due to collision with other members or vibration. Therefore, if the insulating coating 10 is thin at the corners 25c of the substrate 25, the insulating coating 10 at the corners 25c is more susceptible to damage from small impacts or vibrations, resulting in reduced insulation. Therefore, as shown in the first embodiment, the first region 41 preferably includes at least a portion of the corners 25c of the substrate 25. Furthermore, because the insulating coating 10 at the end surfaces 25b of the substrate 25 is likely to be damaged by collision with other members or vibration, similar to the corners 25c, a thicker insulating coating 10 is also preferred at the end surfaces 25b. Therefore, it is more preferable that the first region 41 include at least a portion of the end surfaces 25b of the substrate 25. In such a case, the second region 42 is preferably a region excluding the first region 41 and including at least a part of the main surface portion 25a.

[0055] (Ratio (T1 / T2) of Thickness T1 of the Insulating Coating in the First Region to Thickness T2 of the Insulating Coating in the Second Region: 1.05 or More and 2 or Less) The ratio (T1 / T2) of thickness T1 to thickness T2 will be described using the second embodiment as an example with reference to FIGS. 4A and 4B . In this embodiment, the surface roughness Ra1 of the first region 51 on the main surface 25a is 1 μm or more, and the ratio (Ra1 / Ra2) of the surface roughness Ra1 of the second region 52 on the same surface (main surface 25a) as the first region 51 to the surface roughness Ra2 of the second region 52 is 1.5 or more and 60 or less. Therefore, the thickness T1 of the insulating coating 10 formed on the first region 51 is greater than the thickness T2 of the insulating coating 10 formed on the second region 52. In other words, under the same conditions, the greater the surface roughness Ra1, the greater the thickness of the insulating coating 10 formed in that region. For example, when the first region 51 and the second region 52 are both provided on the main surface 25 a or both provided on the end surface 25 b, the strength of the insulating coating in the first region can be improved if the ratio (T1 / T2) of the thickness T1 of the insulating coating in the first region to the thickness T2 of the insulating coating in the second region is 1.05 or greater. Therefore, the ratio (T1 / T2) of the thickness T1 to the thickness T2 is preferably 1.05 or greater, more preferably 1.1 or greater, and even more preferably 1.15 or greater.

[0056] On the other hand, if the ratio (T1 / T2) of the film thickness T1 to the film thickness T2 is 2 or less, the difference in film thickness between the film thickness T1 and the film thickness T2 will not become too large. Therefore, the ratio (T1 / T2) of the film thickness T1 to the film thickness T2 is preferably 2 or less, more preferably 1.9 or less, and even more preferably 1.8 or less.

[0057] (Ratio (T3 / T4) of Thickness T3 of the Insulating Coating Formed on the Corner Portion in the First Region to Thickness T4 of the Insulating Coating Formed on the Principal Surface Portion in the Second Region: 0.1 to 2) The ratio (T3 / T4) of the thickness T3 of the insulating coating formed on the corner portion 25 c to the thickness T4 of the insulating coating formed on the principal surface portion 25 a will be described with reference to FIG. 2 , taking the first embodiment as an example. Regardless of the shape of the corner, when the material of the insulating coating 10 is applied to the surface of the substrate 25 having a rectangular cross section by a typical method, the thickness of the insulating coating 10 formed on the corner portion 25 c of the substrate 25 will be thinner than the thickness of the insulating coating 10 formed on the region excluding the corner portion 25 c. Therefore, in this embodiment, when the first region 41 includes at least a portion of the corner portion 25 c of the substrate 25 and the second region 42 includes at least a portion of the principal surface portion 25 a of the substrate 25, the ratio of the thickness T3 of the insulating coating formed on the corner portion 25 c to the thickness T4 of the principal surface portion 25 a is specified. This reduces the difference between thickness T1 of insulating coating 10 at corner 25c and thickness T2 of insulating coating 10 on main surface 25a, ensuring a sufficient thickness of insulating coating 10 at corner 25c. If the ratio of thickness T3 to thickness T4 (T3 / T4) is 0.1 or greater, it can be determined that insulating coating 10 at corner 25c is thick enough to prevent peeling. Therefore, the ratio of thickness T3 to thickness T4 (T3 / T4) is preferably 0.1 or greater, more preferably 0.15 or greater, and even more preferably 0.2 or greater.

[0058] On the other hand, if the ratio of thickness T3 to thickness T4 (T3 / T4) is 2 or less, insulating coating 10 at corner 25c can be prevented from becoming too thick and peeling can be suppressed. Therefore, the ratio of thickness T3 to thickness T4 (T3 / T4) is preferably 2 or less, more preferably 1.6 or less, and even more preferably 1.2 or less.

[0059] (Thickness T3 of the insulating coating formed at the corners of the first region: 150 μm or more) When the first region 41 includes a corner 25 c, if the thickness T3 of the insulating coating 10 formed at the corner 25 c is small, the strength of the insulating coating 10 may be insufficient, which may lead to peeling and make it difficult to ensure insulation. Therefore, the thickness T3 of the insulating coating 10 at the corner 25 c is preferably 150 μm or more, and more preferably 200 μm or more. On the other hand, the thicker the insulating coating 10 at the corner 25 c, the higher its strength, but if the thickness is too thick, the manufacturing cost increases and peeling is more likely to occur. Therefore, the thickness T3 of the insulating coating 10 at the corner 25 c is preferably 800 μm or less, and more preferably 600 μm or less.

[0060] Here, methods for measuring the surface roughness Ra1 and the surface roughness Ra2 in the first regions 41, 51 and the second regions 42, 52 of the substrate 25 and methods for measuring the film thicknesses T1 to T4 will be described below with reference to FIGS. 2, 4A, and 4B.

[0061] When measuring the surface roughness of the substrate 25 of the composite member 50, as shown in FIG. 4A , the main surface 25 a and end surface 25 b of the substrate 25 are divided into imaginary frames measuring 1 cm square or 1 cm long. While FIG. 4A depicts the surface of the insulating coating 10 of the composite member 50 as being divided, in reality, the surface of the substrate 25 is divided after the insulating coating 10 has been removed. The surface roughness Ra of each imaginary frame is then measured, for example, at the center of the imaginary frame, in accordance with JIS B 0031. One or a series of imaginary frames with a surface roughness Ra of 1 μm or greater is designated as a first region 51, and the average value of the surface roughnesses of all imaginary frames designated as the first region 51 is designated as the surface roughness Ra1. While it is sufficient to measure the surface roughness Ra at at least one location for each imaginary frame, it is preferable to measure the surface roughness Ra1 at three different locations for each imaginary frame and calculate the average value within each imaginary frame. It is more preferable to measure at five different locations, calculate the average value within each imaginary frame, and then calculate the surface roughness Ra1.

[0062] In addition, one or a series of imaginary frames whose surface roughness measured is equal to or greater than Ra1 / 60 and equal to or less than Ra1 / 1.5 is defined as the second region 52, and the average value of the surface roughness of all the imaginary frames identified as the second region 52 is defined as the surface roughness Ra2.

[0063] In this embodiment, at least a portion of the surface of the substrate 25 includes a first region 51 having a surface roughness Ra1 of 1 μm or greater, and at least a portion of the remaining region includes a second region 52 having a surface roughness Ra2 such that the ratio (Ra1 / Ra2) is 1.5 or greater and 60 or less. In the above description, the first region 51 is located on the main surface 25 a of the substrate 25, but the location of the first region 51 is not limited to the main surface 25 a and may be the end surface 25 b. The first region 51 may be located in one location or multiple locations. However, in order to increase the thickness of the insulating coating 10 in desired areas and ensure strength and insulation, it is preferable that the first region 51 be formed from multiple continuous imaginary frames.

[0064] Furthermore, when measuring the thicknesses T1 and T2 of the insulating coating 10 formed in the first region 51 and the second region 52, the thickness of the insulating coating 10 is measured at any one location for all imaginary frames within the first region 51 and the second region 52 on the same surface. Specifically, when the first region 51 and the second region 52 are present on the principal surface 25a, the thickness of the insulating coating 10 is measured at one location for each imaginary frame within the first region 51 on the principal surface 25a, and the average value is calculated to obtain the thickness T1. Furthermore, the thickness of the insulating coating 10 is measured at one location for each imaginary frame within the second region 52 on the principal surface 25a, and the average value is calculated to obtain the thickness T2.

[0065] When the end surface 25b has a first region 51 and a second region 52, the thickness T1 of the insulating coating 10 is obtained by measuring the thickness of the insulating coating 10 at one location for each imaginary frame within the first region 51 of the end surface 25b and calculating the average value. Similarly, the thickness T2 of the insulating coating 10 is obtained by measuring the thickness of the insulating coating 10 at one location for each imaginary frame within the second region 52 of the end surface 25b and calculating the average value. In other words, when the first region 51 and the second region 52 are located on different planes, the ratio (T1 / T2) of the thickness T1 of the insulating coating 10 formed in the first region 51 to the thickness T2 of the insulating coating 10 formed in the second region 52 is not particularly limited.

[0066] Next, referring to FIG. 2 , a case where the first region 41 includes at least a portion of the corner 25c will be described. In this embodiment, the shape of the corner 25c is not limited and may be rounded or chamfered, or may have a right-angled cross section. Depending on the shape of the corner 25c, it may be difficult to calculate the surface roughnesses Ra1 and Ra2 using the above method. Therefore, if the average surface roughness of an imaginary frame including the corner 25c is 1 μm or greater, this imaginary frame is defined as the first region 41, and it can be determined that the thickness of the insulating coating 10 on the corner 25c included in this imaginary frame is thick. Therefore, to increase the thickness of the insulating coating 10 on the corner 25c, it is preferable that the first region 41 include at least a portion of the corner 25c, and more preferably at least a portion of the end surface 25b. It is also more preferable that the first region 41 include at least a portion of the end surface 25b and at least a portion of the main surface 25a via the corner 25c. The methods for calculating the surface roughness Ra1 in the first region 41 and the surface roughness Ra2 in the second region 42 are as described above.

[0067] In this embodiment, when the first region 41 includes corners 25 c, it is preferable to specify a ratio (T3 / T4) between the thickness T3 of the insulating coating 10 formed on the corners 25 c in the first region 41 and the thickness T4 of the insulating coating 10 formed on the principal surface 25 a in the second region 42. When measuring the thickness of the insulating coating 10 formed on the corners 25 c included in the first region 41, one cross section of each imaginary frame at each corner 25 c included in the first region 41 is observed, the cross section being perpendicular to the direction in which the corners 25 c extend, and the average thickness is calculated. Specifically, as shown in FIG. 2 , extension lines 35 and 36 are drawn on the cross section to the principal surface 25 a and the end surface 25 b of the substrate 25, respectively, and the bisector of the angle formed by the two extension lines 35 and 36 is defined as corner measurement line 37. Then, the corner measurement line 37 is observed for all imaginary frames having corners 25c included in the first region 41, the distance from the surface of the substrate 25 to the surface of the insulating coating 10 is measured, and the average value of the obtained film thickness of the insulating coating 10 is set as the film thickness T3 of the insulating coating formed at the corners.

[0068] The thickness T4 of the insulating coating formed on the main surface portion can be measured in the same manner as the thickness T2 of the insulating coating 10 formed on the second region 52 when the second region 52 is present on the main surface portion 25a in Figure 4A.

[0069] The materials constituting the insulating coating 10 in the composite members 20 and 50 according to this embodiment will be described in further detail below.

[0070] <Insulating Coating> The insulating coating 10 preferably has a matrix (not shown) containing a compound having a siloxane bond and an inorganic material (not shown) dispersed in the matrix. Both the compound having a siloxane bond and the inorganic material have excellent heat resistance and insulating properties, so if the insulating coating 10 contains a compound having a siloxane bond and an inorganic material as components, the insulating coating can have excellent heat resistance and insulating properties.

[0071] Examples of compounds having a siloxane bond (Si—O—Si bond) include silicone and silica sol (silica: SiO ２From the viewpoint of excellent heat resistance and insulating properties, the compound having a siloxane bond contained in the matrix is ​​preferably at least one of silicone and silica sol, and more preferably silicone. It is also a preferred embodiment that the matrix contains both silicone and silica sol.

[0072] (Compound having siloxane bonds: Silicone) Silicone, which is a suitable example of a compound having siloxane bonds and is contained in the matrix of the insulating coating 10, is heated during the curing process of the coating material in the manufacturing method described below, whereby the functional groups disappear and SiO bonds are generated. Furthermore, if a fire or the like occurs near the composite member and the insulating coating 10 is heated to a temperature of, for example, 700°C or higher, the silicone will thermally decompose and produce SiO ２ is generated. Then, this SiO ２ Since the insulating coating 10 containing silicone is not burned even when exposed to flames, the insulating coating 10 can have excellent heat resistance. That is, in the composite members 20 and 50 according to the present embodiment, even when heated at high temperatures, the insulating coating 10 adheres to the substrate 25 without peeling off, and excellent insulating properties and heat resistance can be maintained. Silicone includes silicone resin and silicone rubber, and either can be used, but the use of silicone resin is important because the SiO ２ This is preferable from the viewpoint of increasing the density.

[0073] (Inorganic Material) Inorganic materials have high melting points and excellent heat resistance, so including an inorganic material in the insulating coating 10 can further improve the heat resistance of the insulating coating 10. Furthermore, the inorganic material can also function as a skeleton in the insulating coating 10, thereby improving the strength of the insulating coating 10.

[0074] The inorganic material preferably contains a silicate compound. As described above, silicone, which is an example of a compound having a siloxane bond, is converted into SiO ２ However, silicate compounds can be converted into SiO ２Since the silicate compound has the same components as those of the matrix material containing silicone, it is possible to improve the bonding strength between the matrix material containing silicone and the inorganic material. Note that the silicate compound preferably contains at least one selected from glass-based materials, mica, kaolin, talc, clay, pyrophyllite, montmorillonite, bentonite, wollastonite, xonotlite, zeolite, diatomaceous earth, and halloysite.

[0075] The main component of silica sol (silica), which is another suitable example of a compound having a siloxane bond, is SiO ２ and the silicate compound is silica sol (SiO ２ ), the bonding strength between the matrix containing silica sol (silica) and the inorganic material can also be improved.

[0076] It is also preferable that the inorganic material contains at least one selected from silica, alumina, mullite, zirconia, and calcium carbonate. These materials have high melting points and high insulating properties. Therefore, including these materials in the insulating coating 10 can further improve the heat resistance and insulating properties of the insulating coating 10. When the composite member 20, 50 according to the present embodiment is applied to a busbar, the expected heat exposure temperature of the busbar is equal to or higher than the melting point of the metal material typically used in busbar bodies. In this embodiment, including silica, alumina, mullite, zirconia, calcium carbonate, or the like as an inorganic material can prevent the busbar body from being exposed to high heat because these materials have melting points equal to or higher than the heat exposure temperature. Therefore, these materials are suitable for use as materials for the insulating coating 10.

[0077] The inorganic material preferably has at least one shape selected from the group consisting of flakes, fibers, and particles. When the inorganic material has such a shape, the adhesive strength between the inorganic material and the matrix is ​​increased when the inorganic material is dispersed in the matrix, thereby improving the strength of the insulating coating 10.

[0078] Furthermore, when the inorganic material includes a glass-based material, it is preferable to use at least one selected from a flaky glass-based material, glass particles, and glass fibers as the glass-based material. Among these, the flaky glass-based material is oriented planarly inside the insulating coating 10 and exhibits excellent insulating properties and heat resistance. Therefore, it is particularly preferable that the glass-based material includes a flaky glass-based material. Furthermore, for the same reasons as the flaky glass-based material, it is particularly preferable that mica be used as the inorganic material.

[0079] (Inorganic Material Content) In the composite members 20 and 50 according to the present embodiment, it is preferable to appropriately control the inorganic material content. If the inorganic material content is less than 1% by volume, sufficient insulation and heat resistance may not be obtained. On the other hand, if the inorganic material content exceeds 20% by volume, the viscosity of the coating liquid during production may become too high, making it difficult to form an insulating coating 10 with the desired thickness only in the desired region (first region). Therefore, the inorganic material content of the insulating coating 10 relative to all components is preferably 1 to 20% by volume, more preferably 3 to 15% by volume, and even more preferably 5 to 10% by volume.

[0080] An example of a method for measuring the inorganic material content in the insulating coating 10 is described below. For example, a cross section perpendicular to the main surface 25a is photographed using an electron microscope, and any region within the photograph is selected. Portions of this region that are judged to contain inorganic material are then colored. The total area of ​​the colored region (inorganic material) is then divided by the area of ​​the selected region to calculate the inorganic material content (volume %). The larger the region to be measured and the greater the number of measurement regions, the smaller the error. For example, a rectangular region with a side length in the thickness direction of the insulating coating 10 equal to 90% of the thickness and a side length perpendicular to the thickness direction of 300 μm can be selected. Regarding the number of measurement regions, it is preferable to calculate the content from three different locations on each of the main surface 25a, end surfaces 25b, and corners 25c of the insulating coating 10, and then calculate the average of the entire region. It is more preferable to calculate from five different locations on each of the main surface 25a, end surfaces 25b, and corners 25c.

[0081] In addition to the matrix material and inorganic material described above, insulating coating 10 may contain other materials such as flame retardants, dispersants, pigments, etc., as long as the materials do not affect the insulating properties or heat resistance. As will be described later, insulating coating 10 is formed by applying a coating material (coating liquid) to the surface of a substrate, and it is preferable that the insulating coating contain a thixotropic agent to improve the application performance of the coating liquid containing a matrix material and an inorganic material.

[0082] In the composite members 20 and 50 according to the present embodiment, the insulating coating 10 may have a surface layer made of a matrix material. Also, a resin layer made of a material different from the insulating coating may be provided on the surface of the insulating coating 10. The surface layer, resin layer, substrate, and the like will be further described below.

[0083] <Surface Layer> The insulating coating 10 in the composite member 20, 50 may have a surface layer (not shown) made of a matrix material on at least a portion of its surface. Unlike the coating made of the second coating material described below, the surface layer does not contain an inorganic material and is made only of the matrix material. Therefore, it has high adhesion to the coating made of the first coating material and is harder and denser than the above coating, thereby providing a protective effect for the insulating coating 10. Therefore, the presence of a surface layer on the surface of the insulating coating 10 can suppress damage to the surface of the insulating coating 10 and cushion the impact of a colliding object. Furthermore, the presence of a surface layer can also provide the effect of preventing powder shedding of inorganic materials, etc.

[0084] (Thickness of Surface Layer) When insulating coating 10 has a surface layer, if the thickness of the surface layer is 10 μm or more, the surface layer can provide the effect of protecting insulating coating 10. Furthermore, if the thickness of the surface layer is 100 μm or less, the size of composite member 20, 50 is not affected and an increase in manufacturing costs can be suppressed.

[0085] <Resin Layer> The composite members 20, 50 may have a resin layer containing a resin different from the matrix material on at least a portion of their surface. The resin layer may be made of an insulating resin, such as epoxy resin, nylon resin, SBR (styrene butadiene rubber), silicone rubber, or PVC (polyvinyl chloride). The composite members 20, 50 may have a resin layer, which further improves their insulation and heat resistance. The resin layer may be formed on the surface of the insulating coating 10 where no surface layer is formed, or may be formed on the surface layer.

[0086] (Thickness of Resin Layer) When the composite member 20, 50 has a resin layer, if the thickness of the resin layer is 100 μm or more, the effect of improving insulation and heat resistance can be sufficiently obtained. Therefore, the thickness of the resin layer is preferably 100 μm or more, more preferably 120 μm or more, and even more preferably 150 μm or more. Furthermore, if the thickness of the resin layer is 600 μm or less, it does not affect the size of the composite member 20, 50 and can suppress an increase in manufacturing costs. Therefore, the thickness of the resin layer is preferably 600 μm or less, more preferably 550 μm or less, and even more preferably 500 μm or less.

[0087] <Substrate> In the present embodiment, the substrate 25 is not particularly limited, and the main body portion of various products to which the composite members 20 and 50 according to the present embodiment are applied can be used as the substrate 25. For example, when the composite members 20 and 50 are applied to a bus bar, a conductive material can be used as the substrate 25 for the bus bar main body. Note that the bus bar main body is conductive and electrically conductive, but in the present embodiment, the substrate 25 to be covered with the insulating coating 10 is not limited to a conductive material. For example, a substrate made of an electrically non-conductive material can also be used.

[0088] [Specific Application Examples of Composite Material] There are no particular limitations on the products to which the composite materials 20 and 50 can be applied. As shown in FIG. 1 , in addition to bus bars that connect multiple battery cells or battery modules, the composite materials can be applied to connectors, protective parts for battery modules, cases for electronic components, battery cells, battery modules, battery packs, or motor coils.

[0089] [Method for manufacturing composite member] The composite member according to this embodiment can be manufactured, for example, by the manufacturing method shown below. Figures 5A to 5C are schematic diagrams showing the process steps of a method for manufacturing a composite member according to this embodiment. Note that the manufacturing method shown in Figures 5A to 5C is a method for manufacturing the composite member 20 according to the first embodiment of the present invention, and therefore in Figures 5A to 5C, the same components as those in Figure 2 are designated by the same reference numerals, and detailed descriptions thereof will be omitted or simplified. Furthermore, the manufacturing method described below will be described for the case where the compound having a siloxane bond contained in the matrix is ​​silicone, but it can also be applied to the case where the compound having a siloxane bond is silica sol (silica).

[0090] 5A , abrasive 46 is projected from a nozzle 45 of a blasting device toward the end surface 25b of the substrate 25 to form a first region 41 having a surface roughness of 1 μm or more. A second region 41 having a surface roughness Ra2 is formed so that the ratio (Ra1 / Ra2) of the surface roughness Ra1 of the first region having a surface roughness of 1 μm or more, which is obtained by projecting the abrasive 46, to the surface roughness Ra2 of the region not projected with the abrasive 46, is 1.5 or more and 60 or less. A sealing member (not shown) may be attached to the region not projected with the abrasive 46 to prevent the region from being subjected to the blasting treatment with the abrasive 46.

[0091] When it is desired to form a thick insulating coating on the corners 25c of the substrate 25, it is preferable to project the abrasive 46 onto an area including at least a portion of the corners 25c. For example, it is more preferable to project the abrasive onto an area including at least a portion of the corners 25c and at least a portion of the end surface 25b continuous with the corners 25c. Alternatively, the abrasive may be projected onto an area including at least a portion of the corners 25c and at least a portion of the main surface 25a continuous with the corners 25c.

[0092] (Coating Process) Next, as shown in FIG. 5B , dip coating is performed by immersing the blast-treated substrate 25 in a liquid first coating material 48 filled in a container 47. This causes the first coating material 48 to be coated on at least a portion of the surface of the substrate 25. The first coating material 48 is, for example, an organic solvent to which a matrix material containing silicone (a compound having a siloxane bond) and an inorganic material have been added. When the composite member to be manufactured is applied to a bus bar, it is necessary to prevent the formation of an insulating coating on the connection holes of the bus bar body. Therefore, it is preferable to mask the area including the connection holes before immersing the substrate 25 in the first coating material 48. In this coating process, more first coating material 48 is coated on the blast-treated area (first area 41) of the surface of the substrate 25 than on other areas.

[0093] (First Coating Material Drying Step) After the above-mentioned coating step, the first coating material 48 is dried, if necessary, at a temperature of, for example, 50°C. In this first coating material drying step, the organic solvent is volatilized. In the present invention, the first coating material may be cured without drying, but by performing the drying step, it is possible to prevent the resulting layer from expanding during the curing step. Therefore, it is preferable to perform the first coating material drying step.

[0094] (First Coating Material Curing Process) The dried first coating material 48 is then heated to a temperature of, for example, 200°C to cure. This first coating material curing process causes dehydration condensation of the silicone, forming the insulating coating 10 including the first coating material 48 with a three-dimensional network structure. This first coating material curing process forms numerous pores in the insulating coating. In this embodiment, since the end surface 25b of the substrate 25 is subjected to blasting, a first region 41 is formed on the end surface 25b, as shown in FIG. 5C , and a thick insulating coating 10 is formed on the surfaces of the first region 41 and the corners 25c included in this first region 41.

[0095] According to the manufacturing method of the present embodiment, a specific region on the surface of the substrate 25 is subjected to blasting to form a first region 41 with a rough surface and a second region 42 with a smoother surface than the first region. This allows the thickness of the insulating coating 10 in the specific region to be adjusted to a desired range, preventing a decrease in insulating properties due to partial damage to the insulating coating. Furthermore, the increased adhesive area between the first region 41 and the first coating material 48 on the substrate 25 ensures sufficient adhesion between the two, preventing peeling of the insulating coating 10. Furthermore, since the second region 42, which has a surface roughness less than that of the first region 41, is formed on at least a portion of the main surface 25a of the substrate 25, the insulating coating 10 on the second region 42 is prevented from becoming thicker than necessary, thereby preventing increases in manufacturing costs.

[0096] In the coating step, the method for applying the first coating material 48 to the surface of the substrate 25 is not limited to dip coating, and a painting method may also be used, but dip coating is preferably used, as it allows for easy application in a short time. Furthermore, the strength of the insulating coating can be further improved by forming a first layer through the first coating material curing step, and then forming a second layer through the immersion step in the second coating material described below.

[0097] (Second Coating Material Immersion Process) Subsequently, similar to the coating process shown in FIG. 5B , the substrate 25 having the first layer made of the first coating material 48 is immersed in the second coating material. The second coating material is a material that constitutes at least a portion of the insulating coating 10. For example, the second coating material does not contain an inorganic material and is a matrix material containing silicone added to an organic solvent. The second coating material may not contain the inorganic material of the first coating material, or may be a material different from the matrix material of the first coating material. This second coating material immersion process fills some of the numerous pores formed in the first layer made of the first coating material 48 with the second coating material, thereby reducing the porosity of the first layer. Furthermore, excess second coating material not absorbed into the pores remains on the surface of the first layer.

[0098] (Second Coating Material Drying Process / Second Coating Material Curing Process) Thereafter, if necessary, the second coating material is dried at a temperature of, for example, 50°C, and then heated to a temperature of, for example, 200°C to be cured. This forms a hard second layer made of a silicone-containing matrix material on the surface of the first layer made of the first coating material 48, thereby forming the insulating coating 10 made of the first and second layers. In the present invention, the second coating material may be cured without drying, but performing the drying process can prevent the resulting layer from expanding during the curing process. Therefore, performing the second coating material drying process is preferred.

[0099] (Resin Layer Forming Process) In this embodiment, a resin layer may be formed as needed. Although not shown, a resin layer (not shown) may be formed on the surface of the insulating coating 10 by electrostatic powder coating or fluidized bed dip coating of a resin material containing a resin different from the matrix material, such as an epoxy resin paint. This results in a composite member 20 having the insulating coating 10 and the resin layer on the substrate 25. When forming the resin layer, part of the material constituting the resin layer may penetrate into the first layer made of the first coating material and the second layer made of the second coating material.

[0100] In the above-described manufacturing method, first coating material 48 is applied to the surface of substrate 25, which is then immersed in second coating material, but the steps of applying first coating material 48 and immersing in second coating material may be repeated multiple times until a desired film thickness is achieved. Specifically, first coating material 48 and second coating material are preferably repeatedly layered so that thickness T3 of insulating coating 10 at corner 25c is 150 μm or greater, and more preferably 200 μm or greater.

[0101] In the above-described manufacturing method, the first coating material (coating liquid) is an organic solvent to which a silicone-containing matrix material and an inorganic material have been added, and the second coating material (coating liquid) does not contain an inorganic material and is an organic solvent to which a silicone-containing matrix material has been added. However, depending on the types of the first coating material and second coating material, such as silica sol (silica), the composite member of the present invention can be obtained without performing the above-described immersion step.

[0102] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0103] This application is based on a Japanese patent application (Patent Application No. 2024-030516) filed on February 29, 2024, the contents of which are incorporated herein by reference.

[0104] REFERENCE SIGNS LIST 10 Insulating coating 20, 50 Composite member 25 Base material 25a Main surface portion 25b End surface portion 25c Corner portion 26a, 26b Connection hole 41, 51 First region 42, 52 Second region 45 Nozzle 46 Abrasive material 48 First coating material 110 Battery cell 111 Electrode

Claims

1. A composite member having a substrate and an insulating coating covering at least a portion of the surface of the substrate, wherein the substrate has a first region and a second region having different surface roughnesses, the surface roughness Ra1 of the first region is 1 μm or more, and the ratio of the surface roughness Ra1 of the first region to the surface roughness Ra2 of the second region (Ra1 / Ra2) is 1.5 or more and 60 or less.

2. The composite material described in claim 1, characterized in that the ratio (T1 / T2) of the thickness T1 of the insulating coating formed in the first region to the thickness T2 of the insulating coating formed in the second region is 1.05 or more and 2 or less.

3. The composite member according to claim 1, wherein the substrate has a pair of opposing main surface portions, a plurality of end surface portions connecting the pair of opposing main surface portions, and corner portions between the main surface portions and the end surface portions, the first region includes at least a portion of the corner portions, and the second region is a region excluding the first region and including at least a portion of the main surface portions.

4. A composite material as described in claim 3, characterized in that the ratio (T3 / T4) of the thickness T3 of the insulating coating formed on the corner portion in the first region to the thickness T4 of the insulating coating formed on the main surface portion in the second region is 0.1 or more and 2 or less.

5. The composite member according to claim 4, wherein the thickness T3 is 150 μm or more.

6. The composite member according to claim 3, wherein said first region includes at least a portion of said end surface portion.

7. The composite member according to claim 1, wherein the insulating coating has a matrix containing a compound having a siloxane bond and an inorganic material dispersed in the matrix.

8. The composite member according to claim 7, characterized in that at least a portion of the surface of said insulating coating has a resin layer containing a resin different from the material of said matrix.

9. The composite member according to claim 7, wherein the compound having a siloxane bond is at least one of silicone and silica sol.

10. The composite member according to claim 1, which is used as a bus bar connecting a plurality of battery cells or battery modules.

11. The composite member according to claim 1, which is applied to a connector, a protective part for a battery module, a case for an electronic component, a battery cell, a battery module, a battery pack, or a motor coil.

12. A method for manufacturing a composite member according to any one of claims 1 to 11, comprising: a blasting step of blasting at least a portion of the surface of the base material to form the first region having a surface roughness Ra1 of 1 μm or more; a coating step of coating at least a portion of the surface of the base material with a first coating material so as to include at least a portion of the first region; and a first coating material hardening step of hardening the first coating material, characterized in that the insulating coating containing the first coating material is formed on at least a portion of the surface of the base material.

13. The method for manufacturing a composite member according to claim 12, characterized in that the first coating material includes a matrix material containing a compound having a siloxane bond and an inorganic material.

14. The method for manufacturing a composite member according to claim 13, wherein the compound having a siloxane bond contained in the first coating material is at least one of silicone and silica sol.

15. A method for manufacturing a composite member as described in claim 12, characterized in that the substrate has a pair of opposing main surface portions, a plurality of end surface portions connecting the pair of opposing main surface portions, and corner portions between the main surface portions and the end surface portions, and in the blasting treatment step, abrasive material is projected onto an area including at least a portion of the corner portions.

16. A method for manufacturing a composite member as described in claim 15, characterized in that in the blasting process, an abrasive is projected onto an area including at least a portion of the corner and at least a portion of the end face portion connected to the corner.

17. The method for producing a composite member according to claim 12, wherein in the coating step, the substrate is coated with the first coating material by immersion.

18. A method for manufacturing a composite member according to claim 12, characterized in that a first coating material drying step of drying the first coating material is provided between the coating step and the first coating material hardening step.

19. A method for manufacturing a composite member as described in claim 12, characterized in that after the first coating material hardening step, the method comprises a second coating material immersion step of immersing the substrate on which the coating of the first coating material has been formed in a second coating material, and a second coating material hardening step of hardening the second coating material.

20. A method for manufacturing a composite member as described in claim 19, characterized in that the second coating material is a material that constitutes at least a part of the insulating coating and is made of a matrix material containing a compound having a siloxane bond.

21. The method for producing a composite member according to claim 20, wherein the compound having a siloxane bond contained in the second coating material is at least one of silicone and silica sol.

22. A method for manufacturing a composite member according to claim 19, characterized in that a second coating material drying step for drying the second coating material is provided between the second coating material immersion step and the second coating material hardening step.

23. The method for manufacturing a composite member according to claim 15, wherein the insulating coating is formed so that the thickness of the insulating coating at the corners is 150 μm or more.

24. A method for manufacturing a composite member according to claim 13, characterized in that it includes a resin layer forming step of applying a resin material containing a resin different from the matrix material to at least a portion of the surface and curing the resin material to form a resin layer.

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