FAC flexible circuit board and battery module integrated busbar

Abstract

The utility model relates to an FAC flexible circuit board and a battery module integrated busbar, the FAC flexible circuit board comprises an FFC main body board, the FFC main body board comprises a lead layer and main body film covering layers covering the upper and lower surfaces of the lead layer, the lead layer is composed of a plurality of flat copper wires arranged side by side, a plurality of first welding parts are formed on the lead layer, and a plurality of second welding parts are formed on the main body film covering layers; a plurality of first openings for exposing the first welding parts respectively are formed in the main body film coating layer; the FPC branch plates are welded to the first welding parts in a one-to-one correspondence mode, each FPC branch plate comprises an aluminum sheet and branch film covering layers arranged on the upper face and the lower face of the aluminum sheet in a covering mode, and a second welding part for welding the corresponding first welding part and a third welding part for welding the aluminum bar are formed on the aluminum sheet; and a second opening for exposing the second welding part and a third opening for exposing the third welding part are formed in the branch film coating layer. According to the utility model, the problems of high production cost, low production efficiency, poor environmental protection property and the like of the traditional battery module voltage sampling assembly are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, and particularly relates to a FAC flexible circuit board and an integrated busbar for a battery module. Background Art

[0002] Currently, the integrated busbar for a battery module (abbreviated as CCS) usually uses an FPC (flexible printed circuit board, which is the abbreviation of Flexible Printed Circuit) as a sampling wire harness. Currently, the FPC circuits in CCS are mainly etched, with high etching costs and certain environmental pollution. Moreover, the conductive layer of the FPC is usually copper-based, and the aluminum bar in the CCS has a different material. To achieve direct soldering between the aluminum bar and the copper-based layer, ultrasonic welding needs to be used. However, ultrasonic welding has high requirements for welding points, resulting in low welding yield and low welding efficiency. Although there are many solutions to use nickel sheets for transitional connection, the welding process between the nickel sheet and the FPC involves SMT (surface mounted technology, which is the abbreviation of Surface Mounted Technology) technology and FPC reflow soldering technology, with high production process requirements and high production costs. Summary of the Utility Model

[0003] To solve the above problems, the utility model provides a FAC flexible circuit board and an integrated busbar for a battery module. The FAC (flexible flat cable, which is the abbreviation of Flexible Flat Cable) flexible circuit board adopts a structure combining an aluminum-based FPC branch board and a copper-based FFC main board. This structure eliminates the etching process of the traditional FPC main board, reduces costs, avoids environmental pollution, and uses the aluminum-based FPC branch board to realize the soldering between the aluminum bar and the FFC main board. The soldering process requirements are low, and the production efficiency and product qualification rate can be effectively improved.

[0004] The utility model is realized through the following solutions. A FAC flexible circuit board includes:

[0005] An FFC main board, including a wire layer and main film layers covering the upper and lower surfaces of the wire layer. The wire layer is arranged by a plurality of flat copper wires, and a plurality of first welding parts are formed on the wire layer. A plurality of first openings for respectively exposing the plurality of first welding parts are formed on the main film layer.

[0006] A plurality of FPC branch boards are welded to the plurality of first welding parts one by one. The FPC branch board includes an aluminum sheet and branch film layers covering the upper and lower surfaces of the aluminum sheet. A second welding part for welding the corresponding first welding part and a third welding part for welding an aluminum bar are formed on the aluminum sheet. A second opening for exposing the second welding part and a third opening for exposing the third welding part are formed on the branch film layer.

[0007] A further improvement of the FAC flexible circuit board of the present utility model lies in that: a tin layer is pre-plated on the surface of the flat copper wire, and a nickel layer and a tin layer are pre-plated on the surface of the aluminum sheet.

[0008] A further improvement of the FAC flexible circuit board of the present utility model lies in that: the second welding part and the first welding part are fixedly welded by laser welding, and a plurality of through holes for laser to pass through are formed in the second welding part.

[0009] A further improvement of the FAC flexible circuit board of the present utility model lies in that: the second welding part and the first welding part are fixedly welded by reflow soldering.

[0010] A further improvement of the FAC flexible circuit board of the present utility model lies in that: the third welding part and the aluminum bar are fixedly welded by laser welding.

[0011] A further improvement of the FAC flexible circuit board of the present utility model lies in that: it further includes a connector and an NTC sensor, and both the connector and the NTC sensor are connected to the FFC main board.

[0012] The present utility model further provides a battery module integrated busbar: including a plurality of aluminum bars and the FAC flexible circuit board as described in any one of the above, and the plurality of aluminum bars are fixedly welded to the plurality of third welding parts on the FAC flexible circuit board in a one-to-one correspondence.

[0013] A further improvement of the battery module integrated busbar of the present utility model lies in that: it further includes a quick-press film that is commonly covered on the surfaces of the FAC flexible circuit board and the plurality of aluminum bars to protect the solder joints.

[0014] The FAC flexible circuit board of the present utility model adopts a structure combining an aluminum-based FPC branch board and a copper-based FFC main board. On the one hand, the relatively expensive FPC main board is replaced with an FFC main board, the etching process is cancelled, the cost is reduced, and environmental pollution is avoided; on the other hand, the aluminum-based FPC branch board is used as a connector for connecting the aluminum bars, simplifying the welding process between the main board and the aluminum bars, further reducing the production cost, and improving the production efficiency and the yield rate. By pre-tinning the wire layer and pre-nickeling and tinning the aluminum sheet, it is convenient for subsequent welding of each welding point, which plays an important role in promoting the industrial production of the battery module and can effectively meet the market demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shows a schematic structural diagram of the FAC flexible circuit board in the present utility model.

[0016] Figure 2 Shows a schematic cross-sectional view of the FAC flexible circuit board in the present utility model.

[0017] Figure 3 Shows a schematic structural diagram of the FPC branch board in the present utility model.

[0018] Figure 4 Shows a schematic structural diagram of the aluminum sheet of the FPC branch board in the present utility model.

[0019] Figure 5 Shows a schematic structural diagram of the battery module integrated bus bar before film covering in the present utility model.

[0020] Figure 6 Shows a schematic structural diagram of the battery module integrated bus bar after film covering in the present utility model.

[0021] In the figure: 1. FFC main board; 11. Conductor layer; 111. First welding part; 12. Main body film covering layer; 2. FPC branch board; 21. Aluminum sheet; 211. Second welding part; 212. Third welding part; 213. Through hole; 214. Fuse; 22. Branch film covering layer; 3. Aluminum bar; 4. Connector; 5. Quick pressure film. Specific embodiments

[0022] In order to solve the problems of high component production cost, low production efficiency and poor environmental protection in the traditional battery module voltage, the present utility model provides a FAC flexible circuit board and a battery module integrated bus bar. The following further describes the FAC flexible circuit board and the battery module integrated bus bar with specific embodiments in conjunction with the drawings.

[0023] Refer to Figures 1 to 6 As shown, a FAC flexible circuit board includes an FFC main board 1 and a plurality of FPC branch boards 2. The FFC main board 1 includes a conductor layer 11 and main body film covering layers 12 covering the upper and lower surfaces of the conductor layer 11. The conductor layer 11 is formed by arranging a plurality of flat copper wires, and a plurality of first welding parts 111 are formed on the conductor layer 11. A plurality of first openings for respectively exposing the plurality of first welding parts 111 are formed on the main body film covering layer 12. The plurality of FPC branch boards 2 are welded to the plurality of first welding parts 111 one by one. The FPC branch board 2 includes an aluminum sheet 21 and branch film covering layers 22 covering the upper and lower surfaces of the aluminum sheet 21. A second welding part 211 for welding corresponding to the first welding part 111 and a third welding part 212 for welding the aluminum bar 3 are formed on the aluminum sheet 21. A second opening for exposing the second welding part 211 and a third opening for exposing the third welding part 212 are formed on the branch film covering layer 22.

[0024] On the one hand, in this embodiment, the FPC main board with high cost is replaced by the FFC main board 1. The copper electroplated tin hot pressing process is adopted, the etching process is cancelled, the cost is reduced, and the environmental pollution is avoided. On the other hand, the aluminum-based FPC branch board 2 is used as the connector connecting the aluminum bar 3. Compared with the copper base material, the raw material cost is low, the economy is better, the electrical performance can meet the use requirements, and the traditional form with nickel sheet as the medium for the substitute material can be directly welded between the aluminum base and the aluminum bar, reducing the intermediate link, simplifying the welding process between the main board and the aluminum bar, reducing the material and process costs, and improving the production efficiency and the yield.

[0025] Preferably, each flat copper wire of the wire layer 11 adopts the copper electroplated tin hot pressing process, so that the surface of the flat copper wire is plated with a tin layer, and the aluminum sheet 21 is formed by stamping or die-cutting a whole aluminum sheet raw material pre-plated with a nickel layer and a tin layer. The second welding part 211 and the first welding part 111 can be welded and fixed by laser welding. Correspondingly, a plurality of through holes 213 are formed in the second welding part 211. First, solder is applied to the first welding part 111, and then a laser is applied through the through holes 213 by a laser welding device to realize laser welding. The second welding part 211 and the first welding part 111 can also be welded and fixed by reflow soldering. The third welding part 212 and the aluminum bar 3 can be welded and fixed by laser welding. In this embodiment, by pre-plating tin on the wire layer 11 and pre-plating nickel and tin on the aluminum sheet 21, it is convenient for subsequent welding of each welding point, which plays an important role in promoting the industrial production of the battery module and can effectively meet the market demand.

[0026] Preferably, the FAC flexible circuit board further includes a connector 4 and an NTC sensor (not shown in the figure), and both the connector 4 and the NTC sensor are connected to the FFC main board 1. The connector 4 can be connected to the FFC main board 1 by means of terminal piercing and pressing, or can be connected to the FFC main board 1 by means of a gold finger connection. The traditional soldering connection form is cancelled, the process flow is reduced, and the operation is convenient.

[0027] A preparation method of a FAC flexible circuit board, as shown in Figures 1 to 6 shown, includes the steps:

[0028] Step S1, preparing the FFC main board 1, including the steps:

[0029] Step S11, providing a plurality of circular copper wires, and flattening and drawing the circular copper wires to form flat copper wires.

[0030] Step S12, arranging a plurality of flat copper wires according to the design requirements to form the conductive layer 11.

[0031] Step S13, laminating the upper and lower surfaces of the conductive layer 11 with a film (such as a PI film) to form a main laminating layer 12, and reserving a plurality of first openings on the main laminating layer 12 to expose a plurality of first welding portions 111, such as Figure 2 The position of the first welding portion 111 depends on the layout position of the aluminum bar, and the first opening is reserved corresponding to the position of the first welding portion 111.

[0032] Step S2: preparing a plurality of FPC branch boards 2. The preparation steps of each FPC branch board 2 include:

[0033] Step S21, providing an aluminum sheet raw material, and punching or die-cutting the aluminum sheet raw material to prepare an aluminum sheet 21. In addition to the second welding portion 211 and the third welding portion 212, the aluminum sheet 21 also has a fuse 214, such as Figure 4 As shown, the fuse 214 is relatively thin, and the aluminum sheet 21 can be directly formed by stamping, but laser cutting is required when the aluminum sheet 21 is formed by die cutting. However, both aluminum sheet forming methods can use a whole sheet of aluminum sheet raw material to prepare a number of aluminum sheets at the same time, which has high production efficiency. In addition, if the subsequent welding of the first welding part 111 and the second welding part 211 is in the form of laser welding, then when forming the aluminum sheet 21, it is necessary to set a number of through holes 213 for the laser to pass through in the area corresponding to the second welding part 211 on the aluminum sheet 21. The plurality of through holes 213 can be arranged in multiple rows at intervals as needed, and each row forms a welding area. When welding, part or all of the welding areas can be selected for welding according to actual conditions.

[0034] Step S22: Laminating the upper and lower surfaces of the aluminum sheet 21 to form a branch laminating layer 22, and reserving a second opening and a third opening on the branch laminating layer 22 to expose the second welding portion 211 and the third welding portion 212. In the case where the second welding portion 211 is divided into multiple welding areas, the second opening can also be set to multiple areas, and is used to expose the multiple welding areas one by one.

[0035] Step S3, place several of the FPC branch boards 2 on the FFC main board 1, and make the second welding parts 211 on the several of the FPC branch boards 2 face the several first welding parts 111 on the FFC main board 1 one by one, and make the third welding parts 212 on the several of the FPC branch boards 2 extend out of the FFC main board 1, so as to facilitate the subsequent welding of the aluminum bar 3.

[0036] Step S4: welding and fixing the plurality of second welding parts 211 and the plurality of first welding parts 111 in a one-to-one correspondence. The welding and fixing can be the aforementioned laser welding or reflow welding.

[0037] It should be noted that the above steps S1 and S2 do not have a strict sequence. It is only necessary to complete them before executing step S3. When executing steps S3 and S4, in addition to connecting several FPC branch boards 2 to the FFC main board 1, other components that need to be connected to the FFC main board 1 should also be connected together, such as connectors 4 and NTC sensors.

[0038] Preferably: when executing step S1, after providing several round copper wires, first perform tin plating treatment on each of the round copper wires, and then flatten and draw the tinned round copper wires; after providing the aluminum sheet raw material, first perform tin plating and nickel plating treatment on the aluminum sheet raw material, and then perform stamping or die cutting on the tinned and nickel plated aluminum sheet raw material to form the aluminum sheet 21.

[0039] A battery module integrated busbar, referring to Figure 5 and Figure 6 as shown: it includes several aluminum bars 3 and the FAC flexible circuit board described in any one of the above. Several of these aluminum bars 3 are welded and fixed in one-to-one correspondence with several third welding parts 212 on the FAC flexible circuit board (including the FFC main board 1, FPC branch board 2, connector 4, etc.). Preferably: the battery module integrated busbar further includes a quick-pressure film 5 that is commonly covered on the surfaces of the FAC flexible circuit board and several of these aluminum bars 3 to protect the solder joints.

[0040] When preparing the battery module integrated busbar: first arrange several aluminum bars 3 in two columns and place them at the designed intervals; then place the FAC flexible circuit board between the two columns of aluminum bars 3, so that the third welding parts of several FPC branch boards 2 on both sides of the FFC main board 1 are correspondingly placed on the two columns of aluminum bars 3; then perform laser welding on each aluminum bar 3 and the corresponding third welding part 212; finally, perform the pressing of the quick-pressure film 5 to form the battery module integrated busbar.

[0041] The above has described the present invention in detail with reference to the embodiments of the drawings. Those of ordinary skill in the art can make various variations to the present invention according to the above description. Therefore, some details in the embodiments should not constitute a limitation to the present invention, and the present invention will take the scope defined by the appended claims as the protection scope of the present invention.

Claims

1. A FAC flexible circuit board, characterized in that: include: The FFC main body plate comprises a conductor layer and a main body coating layer covering the upper and lower surfaces of the conductor layer, wherein the conductor layer is formed by arranging a plurality of flat copper wires, a plurality of first welding portions are formed on the conductor layer, and a plurality of first openings for respectively exposing the plurality of first welding portions are opened on the main body coating layer; A plurality of FPC branch boards are welded to a plurality of the first welding parts one by one, and the FPC branch boards include an aluminum sheet and a branch coating layer covered on the upper and lower surfaces of the aluminum sheet, and a second welding part for welding corresponding to the first welding part and a third welding part for welding the aluminum bar are formed on the aluminum sheet, and a second opening for exposing the second welding part and a third opening for exposing the third welding part are formed on the branch coating layer.

2. The FAC flexible circuit board according to claim 1, characterized in that: The surface of the flat copper wire is pre-plated with a tin layer, and the surface of the aluminum sheet is pre-plated with a nickel layer and a tin layer.

3. The FAC flexible circuit board according to claim 1, characterized in that: The second welding portion is fixed to the first welding portion by laser welding, and the second welding portion is provided with a plurality of through holes for laser transmission.

4. The FAC flexible circuit board according to claim 1, characterized in that: The second soldering portion is fixed to the first soldering portion by reflow soldering.

5. The FAC flexible circuit board according to claim 1, characterized in that: The third welding portion is fixed to the aluminum bar by laser welding.

6. The FAC flexible circuit board according to claim 1, characterized in that: It also includes a connector and an NTC sensor, both of which are connected to the FFC main board.

7. A battery module integrated busbar, characterized in that: It comprises a plurality of aluminum bars and the FAC flexible circuit board as claimed in any one of claims 1 to 6, wherein the plurality of aluminum bars are welded and fixed to a plurality of third welding parts on the FAC flexible circuit board in a one-to-one correspondence.

8. The battery module integrated busbar according to claim 7, characterized in that: It also includes a quick-pressing film that is jointly covered on the surface of the FAC flexible circuit board and a plurality of the aluminum bars to protect the solder joints.

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