A low-cost and high-reliability FDC acquisition circuit, its preparation method and application

Abstract

The present invention belongs to the technical field of battery acquisition circuit components, and particularly relates to a low-cost and high-reliability FDC acquisition circuit, a preparation method thereof, and an application. The preparation method comprises the following steps: (1) a composite metal foil with a copper foil in the middle region and aluminum foils in the two side regions is obtained through a solid-phase rolling composite process, and then a wire circuit is processed and formed in the middle copper foil region through an FDC die-cutting process, and connection tabs are processed and formed in the two side aluminum foil regions to obtain an FDC component; (2) the obtained FDC component is welded to a conductive bus connection aluminum row through the connection tabs, and integrally hot-pressed and encapsulated to obtain a low-cost and high-reliability FDC acquisition circuit. The FDC acquisition circuit of the present invention is easy to process, solves the problem of connection between the acquisition circuit and the aluminum bar, and has the advantages of simple structure, small volume, easy installation, good stability and heat resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery acquisition circuit components, and particularly relates to a low-cost and high-reliability FDC acquisition circuit, a preparation method thereof, and an application thereof. Background Art

[0002] The acquisition integrated busbar (CCS or IBB) is a highly integrated battery signal acquisition (such as temperature acquisition, pressure acquisition, etc.) and management system. The existing CCS is mainly assembled by an FPC component and a conductive busbar connecting aluminum bar (aluminum bar) in a certain way. The FPC component includes an FPC board, a connector, a nickel sheet, an NTC resistor, etc. The nickel sheet is mainly used for the transfer welding between the copper circuit of the FPC board and the aluminum bar.

[0003] Currently, the industry generally uses a copper-based wire circuit, which is laser metal welded to the aluminum bar after being transferred through a nickel sheet to complete the connection. There are also technical solutions to reduce costs. After processing the copper circuit by the FDC forming process, it is welded to the aluminum bar through a nickel sheet transfer, but the cost reduction effect of this method is not very significant. There is a technical solution based on the FDC processing circuit, using ultrasonic welding to directly connect the copper circuit to the aluminum bar. However, since it is difficult to confirm the reliability of the solder joint through non-destructive experiments, this connection method has not yet formed a mass production solution in the industry.

[0004] Although the preparation of a lateral composite copper-aluminum composite material through a solid-phase rolling composite process has been reported and there are corresponding commercial products, such as the copper-aluminum composite materials and their manufacturing methods disclosed in CN 102883848 A, CN 110429396 A, and CN 110429397 A. However, it does not disclose improving and applying it to FDC die-cutting processing to prepare FDC components and FDC acquisition circuits to solve the technical problem of stable welding between the copper-based wire circuit and the aluminum bar, as well as solving the technical problems of high-temperature stability, flame retardancy, lightweight, and miniaturization of the FDC acquisition circuit. Summary of the Invention

[0005] Aiming at the above-mentioned disadvantages and deficiencies of the prior art, the primary object of the present invention is to provide a preparation method for a low-cost and high-reliability FDC acquisition circuit.

[0006] Another object of the present invention is to provide a low-cost and high-reliability FDC acquisition circuit prepared by the above method.

[0007] Another object of the present invention is to provide the application of the above low-cost and high-reliability FDC acquisition circuit in the acquisition of battery signals of new energy power battery packs.

[0008] The object of the present invention is achieved by the following technical solutions:

[0009] A preparation method of a low-cost and high-reliability FDC acquisition circuit, comprising the following preparation steps:

[0010] (1) A composite metal foil with a copper foil in the middle region and aluminum foils in both side regions is obtained through a solid-phase rolling composite process. Then, wire circuits are processed and formed in the middle copper foil region through an FDC die-cutting process, and connection electrodes are processed and formed in the aluminum foil regions on both sides to obtain an FDC component;

[0011] (2) The obtained FDC component is integrally hot-press packaged with a conductive busbar connecting aluminum row, and then the connection electrodes are welded to the conductive busbar connecting aluminum row to obtain a low-cost and high-reliability FDC acquisition circuit; or the obtained FDC component is welded to the conductive busbar connecting aluminum row through the connection electrodes, and then integrally hot-press packaged to obtain a low-cost and high-reliability FDC acquisition circuit.

[0012] Further, the solid-phase rolling composite process in step (1) is an existing preparation process, such as the method of using solid-phase bonding to generate side-by-side metal bonding between different materials described in CN102883848A.

[0013] Further, the thickness of the composite metal foil in step (1) is 10 - 140 μm.

[0014] Further, the welding in step (2) uses laser metal welding or ultrasonic welding.

[0015] Further, the integral hot-press packaging in step (2) means hot-press packaging and curing using a packaging adhesive film layer coated with a thermosetting epoxy glue, and the packaging adhesive film layer is a PI or PET protective film.

[0016] Further preferably, the thermosetting epoxy glue is a thermosetting epoxy glue with a flame-retardant function, which is prepared through the following method:

[0017] 1) An inorganic flame retardant is added to a drum dryer, and first, an amino silane coupling agent solution and water are sprayed for surface modification reaction at normal pressure and a temperature of 40 - 60 °C. After the reaction is completed, vacuum is pumped and the temperature is raised to 70 - 100 °C for drying to obtain an amino silane-modified inorganic flame retardant;

[0018] 2) The obtained amino silane-modified inorganic flame retardant is mixed evenly with epoxy resin and a curing agent at room temperature to obtain a thermosetting epoxy glue with a flame-retardant function.

[0019] Further, the inorganic flame retardant in step 1) is at least one of aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, silicon dioxide, and silicate with a particle size of 0.5 - 5 μm.

[0020] Further, the amino-silane coupling agent solution described in step 1) refers to a small molecule alcohol (preferably ethanol, propanol, isopropanol) solution of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane or N-aminoethyl-3-aminopropyltriethoxysilane with a mass fraction of 5% to 10%. The addition amount of the amino-silane coupling agent solution is 1% to 5% of the mass of the inorganic flame retardant in terms of the content of the amino-silane coupling agent.

[0021] Further, the addition amount of water described in step 1) is 30% to 60% of the mass of the amino-silane coupling agent contained in the amino-silane coupling agent solution. By adding a small amount of water during the surface modification reaction process in the present invention, the dealcoholization condensation reaction of the amino-silane coupling agent on the surface of the inorganic flame retardant can be promoted, thereby improving the surface modification effect.

[0022] Further, the epoxy resin described in step 2) is bisphenol A epoxy resin or bisphenol F epoxy resin; the curing agent is at least one of 4,4'-diaminodiphenyl sulfone, dicyandiamide, acid anhydride, imidazole, HDI, TDI, melamine.

[0023] Further, the mass ratio of the amino-silane modified inorganic flame retardant, epoxy resin and curing agent mixed in step 2) is 20 to 60:30 to 80:5 to 15.

[0024] A low-cost and high-reliability FDC acquisition circuit is prepared by the above method.

[0025] Application of the above low-cost and high-reliability FDC acquisition circuit in the acquisition of battery signals of new energy power battery packs.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The FDC acquisition circuit of the present invention not only retains the high current-carrying capacity and easy SMT and other characteristics of copper materials, but also avoids the problem of connecting the acquisition line to the aluminum bar. Through aluminum-aluminum welding, both laser metal welding and ultrasonic welding schemes can be used, avoiding the problems of difficult design of the welding process in the welding area and poor reliability caused by different recrystallization temperatures of copper and aluminum.

[0028] (2) The FDC acquisition circuit of the present invention can also solve the problem of the connection of the copper-aluminum busbar at the output pole of the acquisition component. The structure of the output pole can be designed such that the connection end with the battery cell is still made of aluminum, and the transition part with the power copper busbar is made of copper, avoiding the disadvantages of low reliability of the ultrasonic welding process and limited thickness of the welding material in the transfer scheme; at the same time, it avoids the problem that the high temperature in the welding area causes the grains of the copper-aluminum busbar body to coarsen, the strength to decrease, and the fatigue resistance to deteriorate. There is also a scheme of using nuts to lock the connection part of the copper-aluminum busbar. Compared with the connection scheme of using nuts to lock, the scheme of the present invention saves a first-level connection point, has a lower overall cost and higher reliability.

[0029] (3) The FDC acquisition circuit of the present invention is obtained by hot pressing and curing with an encapsulation adhesive film layer coated with thermosetting epoxy glue, and has the advantages of simple structure, small volume and easy installation.

[0030] (4) The FDC acquisition circuit of the present invention can also integrate a flame retardant function through the encapsulation adhesive film layer. By using a thermosetting epoxy glue with a flame retardant function prepared by a specific method, higher-strength bonding and better high-temperature stability can be achieved. The obtained FDC acquisition circuit has the advantages of good stability and heat resistance. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of the composite metal foil obtained by the present invention;

[0032] Figure 2 is a schematic structural diagram of the FDC component obtained by the present invention;

[0033] Figure 3 is a schematic structural diagram of the FDC acquisition circuit obtained by the present invention;

[0034] The reference numerals in the drawings are explained as follows: 1 - copper foil, 2 - aluminum foil, 3 - wire circuit, 4 - connection pole piece, 5 - conductive busbar connecting aluminum row, 6 - encapsulation adhesive film layer. Detailed Embodiments

[0035] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto. Embodiment 1

[0036] A preparation method of a low-cost and high-reliability FDC acquisition circuit includes the following preparation steps:

[0037] (1) A composite metal foil with a copper foil in the middle region, aluminum foils on both sides, and a thickness of 50 μm is obtained by a solid-phase rolling composite process. The schematic structural diagram of the obtained composite metal foil is as Figure 1As shown. Then, through the FDC die-cutting process, the wire circuit is processed and formed in the middle copper foil area, and the connecting pole pieces are processed and formed in the aluminum foil areas on both sides to obtain the FDC component. The structural schematic diagram of the obtained FDC component is as Figure 2 shown.

[0038] (2) The obtained FDC component is laser metal welded to the conductive busbar connecting aluminum row through the connecting pole pieces, and then hot-press encapsulated and cured using a PET protective film coated with thermosetting epoxy glue to obtain a low-cost and high-reliability FDC acquisition circuit. The structural schematic diagram of the obtained FDC acquisition circuit is as Figure 3 shown.

[0039] The thermosetting epoxy glue is a thermosetting epoxy glue with a flame retardant function, and it is prepared by the following method:

[0040] 1) Add aluminum hydroxide inorganic flame retardant with a particle size of 1 - 2 μm into a drum dryer. First, spray a 5% mass fraction of 3-aminopropyltrimethoxysilane isopropanol solution and water for surface modification reaction at normal pressure and a temperature of 40°C. The addition amount of 3-aminopropyltrimethoxysilane is 1% of the mass of aluminum hydroxide, and the addition amount of water is 60% of the mass of 3-aminopropyltrimethoxysilane. The spraying reaction time is controlled to be 1 h. After the spraying reaction is completed, evacuate and raise the temperature to 70°C for drying to obtain amino-silane modified inorganic flame retardant.

[0041] 2) Mix the obtained amino-silane modified inorganic flame retardant, bisphenol A type epoxy resin E-44, and curing agent 4,4'-diaminodiphenyl sulfone evenly at a mass ratio of 20:80:15 under normal temperature conditions to obtain a thermosetting epoxy glue with a flame retardant function. Example 2

[0042] A preparation method of a low-cost and high-reliability FDC acquisition circuit includes the following preparation steps:

[0043] (1) Obtain a composite metal foil with a copper foil in the middle area, aluminum foils on both sides, and a thickness of 10 μm through a solid-phase rolling composite process. The structural schematic diagram of the obtained composite metal foil is as Figure 1 shown. Then, through the FDC die-cutting process, the wire circuit is processed and formed in the middle copper foil area, and the connecting pole pieces are processed and formed in the aluminum foil areas on both sides to obtain the FDC component. The structural schematic diagram of the obtained FDC component is as Figure 2 shown.

[0044] (2) The obtained FDC component is laser metal welded to the conductive busbar connecting aluminum row through the connecting pole pieces, and then hot-press encapsulated and cured using a PET protective film coated with thermosetting epoxy glue to obtain a low-cost and high-reliability FDC acquisition circuit. The structural schematic diagram of the obtained FDC acquisition circuit is as Figure 3 shown.

[0045] The thermosetting epoxy glue is a thermosetting epoxy glue with flame retardant function, and it is prepared by the following method:

[0046] 1) Add aluminum hydroxide inorganic flame retardant with a particle size of 1-2 μm into a drum dryer, first carry out surface modification reaction by spraying 3-aminopropyltriethoxysilane isopropanol solution with a mass fraction of 7.5% and water at normal pressure and a temperature of 50 °C. The addition amount of 3-aminopropyltriethoxysilane is 3% of the mass of aluminum hydroxide, and the addition amount of water is 45% of the mass of 3-aminopropyltrimethoxysilane. The spraying reaction time is controlled for 1 h. After the spraying reaction is completed, evacuate and heat up to 80 °C for drying to obtain amino-silane modified inorganic flame retardant.

[0047] 2) Mix the obtained amino-silane modified inorganic flame retardant, bisphenol A type epoxy resin E-44 and curing agent 4,4'-diaminodiphenyl sulfone evenly at room temperature according to a mass ratio of 40:60:10 to obtain a thermosetting epoxy glue with flame retardant function. Example 3

[0048] A preparation method of a low-cost and high-reliability FDC acquisition circuit includes the following preparation steps:

[0049] (1) Obtain a composite metal foil with a copper foil in the middle area, aluminum foils on both sides, and a thickness of 140 μm through a solid-phase rolling composite process. The structural schematic diagram of the obtained composite metal foil is as shown in Figure 1 shown. Then, process the wire circuit into the middle copper foil area and the connecting pole piece into the aluminum foil areas on both sides through the FDC die-cutting process to obtain an FDC component. The structural schematic diagram of the obtained FDC component is as shown in Figure 2 shown.

[0050] (2) Laser metal weld the obtained FDC component to the conductive busbar connecting aluminum row through the connecting pole piece, and then use a PET protective film coated with thermosetting epoxy glue for thermocompression encapsulation and curing to obtain a low-cost and high-reliability FDC acquisition circuit. The structural schematic diagram of the obtained FDC acquisition circuit is as shown in Figure 3 shown.

[0051] The thermosetting epoxy glue is a thermosetting epoxy glue with flame retardant function, and it is prepared by the following method:

[0052] 1) Add aluminum hydroxide inorganic flame retardant with a particle size of 1 - 2 μm into a drum dryer. First, spray an isopropanol solution of N - aminoethyl - 3 - aminopropyltriethoxysilane with a mass fraction of 10% and water at normal pressure and a temperature of 60°C for surface modification reaction. The addition amount of N - aminoethyl - 3 - aminopropyltriethoxysilane is 5% of the mass of aluminum hydroxide, and the addition amount of water is 30% of the mass of 3 - aminopropyltrimethoxysilane. Control the spraying reaction time to 1 h. After the spraying reaction is completed, evacuate and heat up to 90°C for drying to obtain amino - silane - modified inorganic flame retardant.

[0053] 2) Mix the obtained amino - silane - modified inorganic flame retardant, bisphenol A - type epoxy resin E - 44 and curing agent 4,4'-diaminodiphenyl sulfone evenly at room temperature according to a mass ratio of 60:40:5 to obtain a thermosetting epoxy glue with flame - retardant function. Example 4

[0054] A preparation method of a low - cost and high - reliability FDC acquisition circuit includes the following preparation steps:

[0055] (1) Obtain a composite metal foil with a copper foil in the middle region, aluminum foils on both sides, and a thickness of 50 μm through a solid - phase rolling composite process. The structural schematic diagram of the obtained composite metal foil is as Figure 1 shown. Then, through the FDC die - cutting process, wire circuits are processed and formed in the middle copper foil area, and connection poles are processed and formed in the aluminum foil areas on both sides to obtain an FDC component. The structural schematic diagram of the obtained FDC component is as Figure 2 shown.

[0056] (2) Laser - metal - weld the obtained FDC component to a conductive bus - bar connection aluminum row through the connection pole, and then use a PET protective film coated with thermosetting epoxy glue for thermocompression encapsulation and curing to obtain a low - cost and high - reliability FDC acquisition circuit. The structural schematic diagram of the obtained FDC acquisition circuit is as Figure 3 shown.

[0057] The thermosetting epoxy glue is a thermosetting epoxy glue with flame - retardant function, which is prepared by the following method:

[0058] 1) Add ammonium polyphosphate and silicon dioxide with a particle size of 1 - 2 μm into a drum dryer according to a mass ratio of 1:1. First, spray an ethanol solution of N - aminoethyl - 3 - aminopropyltrimethoxysilane with a mass fraction of 6% and water at normal pressure and a temperature of 50°C for surface modification reaction. The addition amount of N - aminoethyl - 3 - aminopropyltrimethoxysilane is 2% of the mass of aluminum hydroxide, and the addition amount of water is 40% of the mass of N - aminoethyl - 3 - aminopropyltrimethoxysilane. Control the spraying reaction time to 1 h. After the spraying reaction is completed, evacuate and heat up to 80°C for drying to obtain amino - silane - modified inorganic flame retardant.

[0059] 2) The obtained amino-silane modified inorganic flame retardant, bisphenol F type epoxy resin NPEF-170 and curing agent dicyandiamide were mixed evenly at room temperature according to a mass ratio of 30:70:10 to obtain a thermosetting epoxy glue with flame retardant function.

[0060] Comparative Example 1

[0061] A preparation method of a thermosetting epoxy glue with flame retardant function is obtained by the following method:

[0062] Aluminum hydroxide inorganic flame retardant with a particle size of 1-2 μm, bisphenol A type epoxy resin E-44 and curing agent 4,4'-diaminodiphenyl sulfone were mixed evenly at room temperature according to a mass ratio of 20:80:15 to obtain a thermosetting epoxy glue with flame retardant function.

[0063] Comparative Example 2

[0064] A preparation method of a thermosetting epoxy glue with flame retardant function is obtained by the following method:

[0065] Aluminum hydroxide inorganic flame retardant with a particle size of 1-2 μm, N-aminoethyl-3-aminopropyltriethoxysilane, bisphenol A type epoxy resin E-44 and curing agent 4,4'-diaminodiphenyl sulfone were mixed evenly at room temperature according to a mass ratio of 60:3:40:5 to obtain a thermosetting epoxy glue with flame retardant function.

[0066] The peel strength (180° peel force test was carried out after the epoxy glue was coated on the PET base film and hot-pressed and cured), mechanical properties (tensile strength was tested by a universal mechanical testing machine after the epoxy glue was dried into a film) and heat resistance (the epoxy glue was used for the composite bonding of two pieces of fiberglass cloth, and after hot-pressing and curing, it was put into an oven at 300 °C and baked for 5 min to observe whether there was degumming and cracking) of the thermosetting epoxy glue with flame retardant function obtained in the above examples and comparative examples were tested, and the results are shown in Table 1 below.

[0067] Table 1

[0068] Test sample Peeling strength Tensile strength Heat resistance Example 1 0.82 N / mm 34 MPa No debonding or cracking Example 2 0.74 N / mm 40 MPa No debonding or cracking Example 3 0.65 N / mm 47 MPa No debonding or cracking Example 4 0.70 N / mm 41 MPa No debonding or cracking Comparative Example 1 0.57 N / mm 29 MPa Obvious debonding Comparative Example 2 0.46 N / mm 35 MPa Obvious debonding

[0069] From the comparison results of Comparative Example 1 and Example 1 in Table 1, it can be seen that without using amino silane to modify the surface of the inorganic flame retardant, the peel strength, tensile strength and heat resistance of the obtained thermosetting glue all decreased significantly. From the comparison results of Comparative Example 2 and Example 3, it can be seen that by using the surface spraying process of the present invention to carry out the surface modification reaction on the inorganic flame retardant, the modification effect can be significantly improved. The obtained amino silane-modified inorganic flame retardant can better participate in the curing reaction of epoxy resin, improve the bonding force between the inorganic flame retardant and epoxy resin, and further improve the dispersion effect of the inorganic flame retardant in the thermosetting glue, thereby improving the bonding force, strength and heat resistance stability of the thermosetting epoxy glue.

[0070] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing a low-cost and high-reliability FDC acquisition circuit, characterized in that: The method comprises the following preparation steps: (1) A composite metal foil material with a copper foil in the middle area and aluminum foil on both sides is obtained by solid phase rolling composite process, and then a conductor line is formed in the middle copper foil area by FDC die cutting process, and a connecting electrode is formed in the aluminum foil areas on both sides to obtain an FDC component; (2) The obtained FDC component is integrally hot-pressed and packaged with the conductive busbar connected aluminum busbar, and then the connecting electrode piece and the conductive busbar connected aluminum busbar are welded to obtain a low-cost and high-reliability FDC acquisition circuit; or the obtained FDC component is welded with the conductive busbar connected aluminum busbar through the connecting electrode piece, and then the entire FDC component is hot-pressed and packaged to obtain a low-cost and high-reliability FDC acquisition circuit; The overall hot-pressing packaging in step (2) refers to hot-pressing packaging and curing using a packaging film layer coated with thermosetting epoxy glue, wherein the packaging film layer is a PI or PET protective film; The thermosetting epoxy glue is a thermosetting epoxy glue with flame retardant function, which is prepared by the following method: 1) Add the inorganic flame retardant into a drum dryer, first spray the aminosilane coupling agent solution and water at normal pressure and 40-60°C for surface modification reaction, and after the reaction is completed, evacuate and heat to 70-100°C for drying to obtain the aminosilane-modified inorganic flame retardant; 2) The obtained aminosilane-modified inorganic flame retardant is uniformly mixed with epoxy resin and curing agent at room temperature to obtain a thermosetting epoxy glue with flame retardant function.

2. The method for preparing a low-cost and high-reliability FDC acquisition circuit according to claim 1, characterized in that: The thickness of the composite metal foil in step (1) is 10-140 μm.

3. The method for preparing a low-cost and high-reliability FDC acquisition circuit according to claim 1, characterized in that: The welding in step (2) uses laser metal welding or ultrasonic welding.

4. The method for preparing a low-cost and high-reliability FDC acquisition circuit according to claim 1, characterized in that: The inorganic flame retardant in step 1) is at least one of aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, silicon dioxide and silicate with a particle size of 0.5-5 μm.

5. The method for preparing a low-cost and high-reliability FDC acquisition circuit according to claim 1, characterized in that: The aminosilane coupling agent solution in step 1) refers to a small molecule alcohol solution of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane or N-aminoethyl-3-aminopropyltriethoxysilane with a mass fraction of 5% to 10%; the amount of the aminosilane coupling agent solution added is 1% to 5% of the mass of the inorganic flame retardant based on the aminosilane coupling agent content; the amount of water added is 30% to 60% of the mass of the aminosilane coupling agent contained in the aminosilane coupling agent solution.

6. The method for preparing a low-cost and high-reliability FDC acquisition circuit according to claim 1, characterized in that: In step 2), the epoxy resin is bisphenol A epoxy resin or bisphenol F epoxy resin; the curing agent is at least one of 4,4'-diaminodiphenyl sulfone, dicyandiamide, acid anhydride, imidazole, HDI, TDI, and melamine; and the mass ratio of the aminosilane-modified inorganic flame retardant to the epoxy resin and the curing agent is 20~60:30~80:5~15.

7. A low-cost and high-reliability FDC acquisition circuit, characterized in that: It is prepared by the method according to any one of claims 1 to 6.

8. Application of the low-cost and high-reliability FDC acquisition circuit described in claim 7 in the acquisition of battery signals from new energy power battery packs.

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