Bonding method

Abstract

To provide a bonding method in which an adhesive layer has conductivity when a non-dischargeable member and a dischargeable member are bonded to each other, and that can prevent discharge from a dischargeable member when an adhesive is coated onto the dischargeable member, and can make a cured state of the adhesive uniform in a plane.SOLUTION: There is provided a bonding method for bonding a non-dischargeable member and a dischargeable member using a two-pack type adhesive, wherein the two-pack type adhesive is an adhesive cured by mixing a first agent and a second agent, the first agent is conductive, the second agent is non-conductive, and the method includes coating the first agent onto a surface to be bonded of the non-dischargeable member, bonding the second agent onto a surface to be bonded of the dischargeable member, and bonding the surface to be bonded of the non-dischargeable member and the surface to be bonded of the dischargeable member, thereby curing the adhesive by mixing the first agent and the second agent.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a bonding method for bonding a non-dischargeable member and a dischargeable member. [Background technology]

[0002] One example of a battery structure is a battery pack in which a plurality of unit cells sealed in an exterior member such as a laminate film are stacked together. In order to prevent the unit cells of this battery pack from shifting from one another, the following battery pack has been disclosed in which the unit cells are fixed together with an adhesive.

[0003] For example, Patent Document 1 discloses a battery assembly including a plurality of flat-shaped unit cells each formed by sealing a power generating element, in which positive and negative plates are laminated, in an exterior member, and the overlapping unit cells are joined together with an adhesive that hardens after they come into contact with each other. According to the battery assembly of Patent Document 1, since the unit cells are joined together with an adhesive that hardens after they come into contact with each other, the adhesive does not harden before the unit cells are stacked, and it can be used when the production line is stopped, for example, and it is said to have a good yield. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-172994 A Summary of the Invention [Problem to be solved by the invention]

[0005] As the energy density and current density required of batteries increase, the heat generated by the cells tends to increase. In order to dissipate the heat generated by the cells, a battery pack structure in which a cooler is provided between the cells is sometimes used.

[0006] When the unit cells are stacked in series in such a battery pack structure, the adhesive layer between the unit cells and the cooler is required to have not only thermal conductivity but also electrical conductivity.

[0007] When electrical conductivity is required in the adhesive layer as described above, it is possible to use a conductive adhesive to fix the unit cell and the cooler. However, when the unit cell is in a dischargeable state, if the conductive adhesive is applied to the surface of the unit cell, there is a risk that the unit cell will discharge through the conductive adhesive and the application device such as a dispenser.

[0008] Therefore, an object of the present disclosure is to provide a bonding method for bonding a non-dischargeable component and a dischargeable component, which not only has an adhesive layer that is conductive, but also can prevent discharges from the dischargeable component even when adhesive is applied to the dischargeable component, and can make the hardened state of the adhesive uniform within the surface. [Means for solving the problem]

[0009] The present disclosure achieves the above object by the following means.

[0010] <1> A bonding method for bonding a non-dischargeable member and a dischargeable member using a two-component adhesive, comprising the steps of: The two-component adhesive is an adhesive that is cured by mixing a first component and a second component, The first agent is conductive, The second part is non-conductive; and The above method is applying the first agent to the adherend surface of the non-dischargeable member; Applying the second agent to the adherend surface of the dischargeable member; and bonding a surface to be adhered of the non-dischargeable member and a surface to be adhered of the dischargeable member, thereby mixing and curing the first agent and the second agent; Including, Adhesion method. Effect of the Invention

[0011] According to the bonding method disclosed herein, when bonding a non-dischargeable member and a dischargeable member, not only is the adhesive layer conductive, but even when the adhesive is applied to the dischargeable member, discharges from the dischargeable member can be prevented and the hardened state of the adhesive can be made uniform within the surface. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram for illustrating the application of a two-component adhesive to the adherend surfaces of a non-dischargeable member and a dischargeable member in the adhesion method of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram for illustrating bonding a non-dischargeable member and a dischargeable member together and curing the first agent and the second agent in the bonding method of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present disclosure. In addition, in the description of the drawings, the same elements are given the same reference numerals, and duplicated descriptions will be omitted.

[0014] 《Adhesive method》 The bonding method of the present disclosure includes: A bonding method for bonding a non-dischargeable member and a dischargeable member using a two-component adhesive, comprising the steps of: The two-component adhesive is an adhesive that is cured by mixing a first component and a second component, The first agent is conductive, The second part is non-conductive; and The above method is applying the first agent to the adherend surface of the non-dischargeable member; Applying the second agent to the adherend surface of the dischargeable member; and bonding a surface to be adhered of the non-dischargeable member and a surface to be adhered of the dischargeable member, thereby mixing and curing the first agent and the second agent; Includes.

[0015] According to the bonding method disclosed herein, when bonding a non-dischargeable component and a dischargeable component, not only is the adhesive layer conductive, but even when the adhesive is applied to the dischargeable component, discharge from the dischargeable component can be prevented, and the hardened state of the adhesive can be made uniform within the surface.

[0016] In the present disclosure, a two-component adhesive in which a first agent and a second agent are mixed and cured is used to bond a non-dischargeable member and a dischargeable member. The first agent, for example, contains a conductive filler and is conductive. On the other hand, the second agent, for example, does not contain a conductive filler and is non-conductive. Here, when the conductive first agent and the non-conductive second agent have a viscosity of, for example, 0.1 to 10 Pa·s, the conductive filler diffuses into each other by self-diffusion when they are bonded together, and the adhesive layer obtained by mixing and curing the first agent and the second agent is considered to have conductivity. Also, when the conductive first agent and the non-conductive second agent have a viscosity of, for example, greater than 10 Pa·s, the conductive filler diffuses by promoting diffusion by vibration or the like, and the adhesive layer obtained by mixing and curing the first agent and the second agent is considered to have conductivity.

[0017] In the present disclosure, a conductive first agent is applied to a non-dischargeable member (specifically, for example, a cooler), and a non-conductive second agent is applied to a dischargeable member (specifically, for example, a charged battery). Since the non-conductive second agent is applied to the dischargeable member, when applying the adhesive, it is possible to prevent discharge from the dischargeable member through an application device such as a dispenser. In addition, since the hardening of the adhesive starts when the non-dischargeable member and the dischargeable member are attached to each other, the hardened state of the adhesive can be made uniform within the surface.

[0018] <Two-component adhesive> The two-part adhesive of the present disclosure is an adhesive that is cured by mixing a first part and a second part.

[0019] The two-component adhesive is not particularly limited as long as it is an adhesive that uses a first agent and a second agent. The combination of the first agent and the second agent of the two-component adhesive is not particularly limited. Examples of the two-component adhesive include, but are not limited to, acrylic adhesives, unsaturated polyester adhesives, vinyl ester adhesives, epoxy adhesives, urethane adhesives, modified silicone adhesives, and polysulfide adhesives.

[0020] <First and second agents> In the two-component adhesive used in the present disclosure, The first agent is conductive, The second part is non-conductive.

[0021] (First Agent) The first agent is conductive and may contain, but is not limited to, a conductive filler.

[0022] The conductive filler may be selected from materials having electrical conductivity. The material of the conductive filler is not particularly limited, but may include metal, carbon, and mixtures thereof. The metal may include, for example, copper, iron, gold, silver, platinum, nickel, zinc, tin, aluminum, stainless steel, titanium, and mixtures thereof, and the carbon may include, for example, graphite, carbon black, carbon nanotubes, and mixtures thereof. The conductive filler is not particularly limited, but is preferably a conductive filler containing copper or iron.

[0023] These conductive fillers may be used alone or in combination of two or more. In addition, alloys or metal oxides of these may be used. Furthermore, the conductive fillers may be particulate ceramic materials or resin materials coated with metal by plating or the like.

[0024] When the first agent contains a conductive filler, the content of the conductive filler may be 50 mass% or more, 55 mass% or more, 60 mass% or more, 65 mass% or more, 70 mass% or more, 75 mass% or more, or 80 mass% or more relative to the total amount of the first agent, from the viewpoint of reducing the contact resistance of the adhesive layer after the two-component adhesive is cured. The content of the conductive filler may be 95 mass% or less, 90 mass% or less, 85 mass% or less, 80 mass% or less, 75 mass% or less, or 70 mass% or less relative to the total amount of the first agent, from the viewpoint of the adhesive strength of the adhesive layer after the two-component adhesive is cured.

[0025] The viscosity of the first agent is not particularly limited, and may be 0.01 Pa·s or more, 0.05 Pa·s or more, 0.10 Pa·s or more, 0.20 Pa·s or more, or 0.50 Pa·s or more, and may be 100 Pa·s or less, 50 Pa·s or less, 20 Pa·s or less, 10 Pa·s or less, or 5 Pa·s or less. Here, the viscosity of the first agent can be determined at 25°C using an E-type viscometer.

[0026] (Second agent) The second agent is non-conductive and, although not particularly limited thereto, may be used as is without containing a conductive filler.

[0027] The viscosity of the second part is not particularly limited, and may be 0.01 Pa·s or more, 0.05 Pa·s or more, 0.10 Pa·s or more, 0.20 Pa·s or more, or 0.50 Pa·s or more, and may be 100 Pa·s or less, 50 Pa·s or less, 20 Pa·s or less, 10 Pa·s or less, or 5 Pa·s or less. Here, the viscosity of the second part can be determined at 25°C using an E-type viscometer.

[0028] <Application of the first and second agents> The bonding method of the present disclosure includes: applying the first agent to the adherend surface of the non-dischargeable member; The method includes applying the second agent to the adherend surface of the dischargeable member.

[0029] The non-dischargeable member is not particularly limited as long as it is a member that does not discharge electricity. An example of the non-dischargeable member is a cooler, but is not limited to this.

[0030] The dischargeable member is not particularly limited as long as it is a member that can discharge. Examples of the dischargeable member include, but are not limited to, a dischargeable battery, a dischargeable battery pack, a dischargeable single cell, and the like.

[0031] The method for applying the first and second agents is not particularly limited, but the first and second agents may be applied to the adherend surface using a dispenser.

[0032] FIG. 1 is a schematic diagram showing one embodiment of applying a two-component adhesive to the adherend surfaces of a non-dischargeable member and a dischargeable member in the adhesion method of the present disclosure, but the present invention is not limited to this embodiment.

[0033] By applying the first agent to the adherend surface 10a of the non-dischargeable member 10, a coating film 11 of the first agent is formed on the adherend surface 10a of the non-dischargeable member 10. Similarly, by applying the second agent to the adherend surface 12a of the dischargeable member 12, a coating film 13 of the second agent is formed on the adherend surface 12a of the dischargeable member 12. Since the non-conductive second agent is applied to the dischargeable member 12, discharge from the dischargeable member 12 can be prevented. Furthermore, the two-agent adhesive used in the bonding method of the present disclosure hardens when the first agent and the second agent are mixed, so hardening can be prevented when the first agent is applied to the non-dischargeable member 10 and when the second agent is applied to the dischargeable member 12.

[0034] <Bonding of Non-Dischargeable Member and Dischargeable Member> The bonding method of the present disclosure includes bonding a surface of the non-dischargeable member to a surface of the dischargeable member to be bonded, thereby mixing and curing the first agent and the second agent.

[0035] FIG. 2 is a schematic diagram showing one embodiment of bonding a non-dischargeable member and a dischargeable member in the bonding method of the present disclosure, but the present invention is not limited to this embodiment.

[0036] In FIG. 2(A), the adherend surface of the non-dischargeable member 10 and the adherend surface of the dischargeable member 12 are bonded together via a coating film 11 of the first agent and a coating film 13 of the second agent. By bonding them together, the first agent and the second agent are mixed and hardened as shown in FIG. 2(B), forming a conductive adhesive layer 14. Since the two-agent adhesive hardens when mixed, the hardened state of the adhesive layer can be made uniform within the surface. When the viscosity of the first agent and the second agent is, for example, 0.1 to 10 Pa·s, the conductive first agent and the non-conductive second agent are made uniform by self-diffusion, forming a conductive adhesive layer. When the viscosity of the first agent and the second agent is high and they do not self-diffuse, they may be moved in the shear direction to promote diffusion, thereby forming a conductive adhesive layer.

[0037] The conductive adhesive layer is not particularly limited as long as it is a layer having conductivity. The contact resistance between the non-dischargeable member and the dischargeable member via the conductive adhesive layer may be 10Ω or less, 5Ω or less, or 1Ω or less, or may be 0.001Ω or more, 0.01Ω or more, or 0.1Ω or more. EXAMPLES

[0038] The present disclosure will be described in more detail with reference to the following examples, but the scope of the present disclosure is not limited to these examples.

[0039] Example 1 In a two-component adhesive in which the first and second components are mixed, a conductive filler containing Cu (copper) (hereafter referred to as Cu-based conductive filler) was added only to the first component. The first component was conductive, and the second component was non-conductive.

[0040] A first agent containing a Cu-based conductive filler was applied to substrate 1, and a second agent was applied to substrate 2. Next, substrate 1 to which the first agent was applied and substrate 2 to which the second agent was applied were bonded together, and the two-agent adhesive was cured.

[0041] The contact resistance of the substrate 1 and the substrate 2 bonded together using the first agent containing the Cu-based conductive filler and the second agent was 0.5Ω.

[0042] The results of Example 1 are shown in Table 1 below.

[0043] The evaluation was performed under the assumption that substrate 1 is a non-dischargeable material and substrate 2 is a dischargeable material. A or B listed in the evaluation results for "dischargeability" in Table 1 means the following. A: There is no risk of discharge from the substrate 2 (dischargeable member). B: There is a risk of discharge from substrate 2 (dischargeable member).

[0044] The letters A and B in the evaluation results for "curing uniformity" in Table 1 mean the following: A: Hardening is uniform across the surface. B: Hardening is non-uniform across the surface.

[0045] Example 2 In a two-component adhesive in which the first and second components are mixed, a conductive filler containing Fe (iron) (hereafter referred to as Fe-based conductive filler) was added only to the first component. The first component was conductive, and the second component was non-conductive.

[0046] A first agent containing an Fe-based conductive filler was applied to a substrate 1, and a second agent was applied to a substrate 2. Next, the substrate 1 to which the first agent was applied and the substrate 2 to which the second agent was applied were bonded together, and the two-agent adhesive was cured.

[0047] The contact resistance of the substrate 1 and the substrate 2 bonded together using the first agent containing the Fe-based conductive filler and the second agent was 0.4 Ω. The results of Example 2 are shown in Table 1 below.

[0048] Comparative Example 1 In a two-component adhesive in which a first component and a second component are mixed, the first component and the second component were mixed without adding a conductive filler. The mixture of the first component and the second component was non-conductive.

[0049] The mixture of the first and second agents was applied to the substrate 2. Next, the substrate 1 and the substrate 2 to which the mixture of the first and second agents had been applied were attached to each other, and the two-agent adhesive was cured.

[0050] The contact resistance of the substrate 1 and the substrate 2 bonded together with a two-component adhesive containing no conductive filler exceeded 40 MΩ, which is the limit of the measuring device, and was therefore unmeasurable. The results of Comparative Example 1 are shown in Table 1 below.

[0051] Comparative Example 2 In a two-component adhesive in which the first and second components are mixed, the first and second components and a Cu-based conductive filler were mixed and used. The mixture of the first and second components and the Cu-based conductive filler was conductive.

[0052] The mixture of the first agent, the second agent, and the Cu-based conductive filler was applied to the substrate 2. Next, the substrate 1 and the substrate 2 to which the mixture of the first agent, the second agent, and the Cu-based conductive filler had been applied were attached to each other, and the two-part adhesive was cured.

[0053] The contact resistance of the substrate 1 and the substrate 2 bonded together with the two-component adhesive containing the Cu-based conductive filler was 0.4 Ω. The results of Comparative Example 2 are shown in Table 1 below.

[0054] Comparative Example 3 In a two-component adhesive in which the first and second components are mixed, the first and second components and an Fe-based conductive filler were mixed and used. The mixture of the first and second components and the Fe-based conductive filler was conductive.

[0055] The mixture of the first agent, the second agent, and the Fe-based conductive filler was applied to the substrate 2. Next, the substrate 1 and the substrate 2 to which the mixture of the first agent, the second agent, and the Fe-based conductive filler had been applied were bonded together, and the two-part adhesive was cured.

[0056] The contact resistance of the substrate 1 and the substrate 2 bonded together with the two-component adhesive containing the Fe-based conductive filler was 0.6 Ω. The results of Comparative Example 3 are shown in Table 1 below.

[0057] [Table 1]

[0058] When the two-component adhesive did not contain a conductive filler, the adhesive layers of the substrates A and B did not exhibit conductivity and had high resistance. In contrast, when the Cu-based conductive filler was contained only in the first component (Example 1), the adhesive layers of the substrates A and B exhibited conductivity and the contact resistance was 0.5Ω. In addition, when the substrates were bonded using a mixture of the first component, the second component, and the Cu-based conductive filler (Comparative Example 2), the contact resistance was also 0.4Ω. Since both adhesive layers exhibited conductivity and had the same contact resistance, it is believed that the Cu-based conductive filler added only to the first component self-diffused when the two components were bonded together to form a conductive adhesive layer. It is believed that the same was true for the Fe-based conductive filler (Example 2, Comparative Example 3).

[0059] Even if the conductive filler is added only to the first agent, when the first agent and the second agent are brought into contact with each other, a conductive adhesive layer can be formed due to the self-diffusion of the conductive filler, so it is considered that, for example, the possibility of discharge from the dischargeable member can be avoided by applying the second agent that does not contain the conductive filler to the dischargeable member. In addition, since the first agent and the second agent start to harden when they are brought into contact with each other, the hardening reaction starts when they are brought into contact with each other, and uniform hardening can be achieved in the adhesive layer.

[0060] Although preferred embodiments of the cells of the present disclosure have been described, those skilled in the art will recognize that modifications may be made without departing from the scope of the claims. [Explanation of symbols]

[0061] 10 Non-dischargeable materials 10a: Adhered surface of non-dischargeable member 11 Coating of the first agent 12 Dischargeable materials 12a Adhered surface of dischargeable member 13 Coating of the second agent 14 Adhesive layer

Claims

[Claim 1] A bonding method for bonding a non-dischargeable member and a dischargeable member using a two-component adhesive, comprising the steps of: The two-component adhesive is an adhesive that is cured by mixing a first component and a second component, The first agent is conductive, the second part is non-conductive; and The method further comprising: applying the first agent to a surface to be adhered of the non-dischargeable member; applying the second agent to the adherend surface of the dischargeable member; and bonding a surface to be adhered of the non-dischargeable member and a surface to be adhered of the dischargeable member, thereby mixing and curing the first agent and the second agent; Including, Adhesion method.

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