Novel CCS adopting single-layer flexible board and multi-layer flexible combination technology

Abstract

A novel CCS adopting a single-layer flexible board and multi-layer flexible combination technology belongs to the technical field of layout and structural design of lithium battery integrated busbars, and comprises a flexible board assembly and a base plate for supporting the flexible board assembly, at least one end of the flexible board assembly is provided with a connector, the connector is hung outside the area of the base plate, and the flexible board assembly is connected with the base plate. The flexible board assembly comprises a single-face flexible circuit board serving as a main board, at least one end of the single-face flexible circuit board is provided with a connector, the connector comprises a double-face flexible plug board welded to the end of the single-face flexible circuit board, and a welding area is formed at the welding position of the double-face flexible plug board and the end of the single-face flexible circuit board. And a group of substrates are arranged in the welding area to clamp and fix the welding area. In order to solve the problems that a large number of transmission lines of an electric plug are needed and the size is large during large-capacity data transmission in the prior art, the invention provides the internal interconnection board of the power battery with a small-size double-sided transmission line connecting part.

Description

Technical Field

[0001] This application belongs to the technical field of the layout and structural design of lithium battery integrated busbars, and particularly relates to a new type of CCS that adopts the technology of combining single-layer flexible boards with multi-layer flexible boards. Background Art

[0002] With the rapid development of the electric vehicle industry, the battery management system (BMS) has become a key technology to ensure the safe and efficient operation of electric vehicles. Among them, signal acquisition from battery cells through flexible printed circuit boards (FPCs) is a common implementation method. The FPC signal acquisition board is mainly used to measure the voltage, current, and temperature of battery cells to achieve real-time monitoring and management of the battery state. However, there are several significant technical limitations and challenges in the FPC signal acquisition boards used in existing automotive BMS systems.

[0003] First of all, the current FPC signal acquisition boards generally exceed 1.8 meters in length. Such a design not only increases the complexity of the printed circuit board manufacturing process but also requires at least two folding and aligning operations to be correctly installed when finally assembled into the battery pack. This process is not only cumbersome but also extremely likely to generate cracks at the bending points of the FPC, thus affecting the accurate acquisition of signals and endangering the safety of cell signal sampling. Secondly, due to the length of the FPC signal acquisition board, the information transmission path from cell detection is too long, which will introduce time delay, affecting the ability of the control device to make a quick and accurate judgment on the battery state. In the case of partial cell failure, the overly long FPC signal acquisition board is also not conducive to the disassembly, installation, and replacement of battery modules, affecting the maintenance efficiency and cost of the system. In addition, when components on the FPC detection board, such as NTC negative temperature coefficient thermistors, fuses, etc., are damaged, the entire long board needs to be replaced, significantly increasing the maintenance cost.

[0004] In the published document with the publication number CN219718569U and the theme of a flexible circuit board for a new energy vehicle battery, an electrical plug is installed at one end of the flexible board body. The electrical plug is electrically connected to the copper foil layer, and a reinforcing board is installed between the electrical plug and the flexible board body. This electrical plug has only one set of circuits for transmission. However, at present, the data transmission volume of the electric control system of electric vehicles is large, and one set of circuits is obviously insufficient. But when assembling the existing electric control system using existing technologies, the volume of the electrical plug will become larger, which is not conducive to the miniaturization of the entire battery pack volume.

[0005] In the multi-segment signal acquisition component and battery management system with the publication number CN222339392U, it uses multiple circuit boards; multiple wireless transmission modules, each wireless transmission module is arranged on a circuit board, and every two adjacent wireless transmission modules have wireless communication functions. Each wireless transmission module includes: an analog front end, connected to the circuit board, for converting the signals of the battery cells to obtain secondary signals; a wireless communication chip, connected to the analog front end, for wirelessly receiving and transmitting the secondary signals, and a power supply chip, connected to the analog front end and the wireless communication chip, and the power supply chip is used to connect to the battery cells and provide electrical energy for the analog front end and the wireless communication chip.

[0006] In this technical solution, by arranging one wireless transmission module on each circuit board in the multi-segment signal acquisition component, the signal transmission between every two adjacent circuit boards does not require physical connection, folding, or alignment. The technical personnel of the applicant believe that the information transmission between wireless transmission modules will be greatly interfered, and the information transmission between each module will also interfere with each other, which is not conducive to the safety of the whole vehicle. Summary of the Invention

[0007] The first object of the present invention is to provide an internal interconnection board for a power battery with a connection part having a small volume and a double-sided transmission route connection part in view of the problems that when transmitting a large amount of data currently, there are many transmission routes with electrical plugs and large volumes.

[0008] Then, in view of the problem that there is a difference in the thermal expansion coefficient between the FPC signal acquisition board and the sensor during hot and cold alternation, which is prone to cause interface delamination under long-term thermal cycling, and the problem that the process steps of the rigid-flexible board combination technology need to simultaneously process processes such as laser micro-hole interconnection of rigid PCBs and flexible FPCs and embedded sensor packaging, and the process steps increase by more than 40% compared with traditional rigid boards, a new CCS using a single-layer flexible board and multi-layer flexible combination technology is provided, in which the signal acquisition pins extended from the FPC are made into rigid boards with a thermal expansion coefficient more matched with copper-aluminum bars and pads.

[0009] To achieve the above first technical object, the following technical solution is provided. A new CCS using a single-layer flexible board and multi-layer flexible combination technology includes a flexible board assembly and a pad supporting the flexible board assembly. At least one end of the flexible board assembly is equipped with a connector, and the connector hangs outside the pad area. The flexible board assembly includes a single-sided flexible circuit board as the main board. At least one end of the single-sided flexible circuit board is provided with a connector. The connector includes a double-sided flexible plug-in board welded to the end of the single-sided flexible circuit board. The welding area formed at the welding part of the double-sided flexible plug-in board and the end of the single-sided flexible circuit board is provided with a set of substrates to clamp and fix the welding area.

[0010] In order to achieve the above-mentioned second technical objective, in this embodiment, there are several electrode series connection units on the backing plate. The electrode series connection units can be divided into at least 4 groups of electrode series connection groups. At least one electrode series connection unit in each group of electrode series connection groups is provided with a rigid board assembly for signal acquisition. Among them, the rigid board assembly has at least two connection parts. A graphene silver paste composite conductive layer is sprayed on the connection parts to form connection pins. One of the connection pins is connected to the copper-aluminum row clamped in the electrode series connection unit, and the other connection pin is connected to the single-sided flexible circuit board fixed on the backing plate.

[0011] In this embodiment, the thickness of the graphene silver paste composite conductive layer sprayed in the rigid-flexible junction area is 50 nm, which improves the impedance fluctuation of high-frequency signal transmission stability ≤ ±3%. During the thermal expansion process, the graphene silver paste composite conductive layer has an elastic telescopic function, and realizes electrical connection with the rigid board assembly on the premise of keeping the single-sided flexible circuit board unchanged.

[0012] In an implementable manner, a silver-based conductive adhesive layer needs to be coated during the installation of the connection pins to ensure good integrated connection in the rigid-flexible junction area. And the temperature resistance range of this colloid is: short-term temperature resistance up to 500 °C, long-term working temperature ≤ 300 °C. It also has the characteristics of: using silver powder as the conductive filler, low resistivity ≤ 1×10-4 Ω·cm, suitable for fixing PCB components and electromagnetic shielding.

[0013] In an implementable manner, the electrode series connection unit includes an electrode groove formed by the upper surface of the backing plate recessing downward for clamping the copper-aluminum row, and a copper-aluminum row embedded in the electrode groove.

[0014] In an implementable manner, the electrode groove includes a dividing groove that recesses downward and transversely cuts the electrode groove, and the dividing groove cooperates with the convex strip on the copper-aluminum row; and a channel extending to the backing plate outside the electrode groove, in which a metal sheet for connecting with the single-sided flexible circuit board is arranged; it also includes two through holes that are clamped with the battery pole and connected to the copper-aluminum row and are located on both sides of the dividing groove; and fixing columns for fixing the copper-aluminum row are arranged in the electrode groove beside the through holes. The fixing method of the copper-aluminum row can ensure the accuracy of its position.

[0015] In another implementable manner, a graphene silver paste composite conductive layer is arranged between the copper-aluminum row and the single-sided flexible circuit board and is fixed through a silver-based conductive adhesive layer.

[0016] In an implementable manner, the electrode series unit with a rigid board assembly further includes a rigid board slot located in the electrode slot on one side of the polarization slot. The rigid board slot is located in the electrode slot on the other side of the channel, a PCB rigid board fitted in the rigid board slot, and a collection hole for placing a sensor device is provided in the rigid board slot and penetrates through the PCB rigid board; holes are provided on the PCB rigid board for cooperation with fixing posts. The setting of the rigid board assembly simplifies the wiring of the single-sided flexible circuit board and can also ensure the welding stability and reliability of the product. Moreover, there will be no welding points on the single-sided flexible circuit board during processing.

[0017] In an implementable manner, at least one convex post is provided on the PCB rigid board at the end of the collection hole; a collection board is fixed on the PCB rigid board. The lower surface of the collection board is connected to the sensor device through a graphene silver paste composite conductive layer, and the upper surface is connected to the single-sided flexible circuit board through a coated silver-based conductive adhesive layer. Among them, the single-sided flexible circuit board adhered to the collection board is also fixed on the convex post.

[0018] In an implementable manner, the electrode series groups on a straight line adopt one single-sided flexible circuit board, and a plurality of heat dissipation holes are provided in the backing plate below the single-sided flexible circuit board; and a plurality of fixed anchor bolts are evenly arranged on the backing plate to fix the single-sided flexible circuit board.

[0019] The present invention has the following beneficial effects compared with the prior art:

[0020] In this design, the double-sided flexible plug-in board is welded to the single-sided flexible circuit board. This technology can use two fewer flexible board connectors when used in automotive battery CCS, saving costs. And it can solve the pain point that the wire sequence cannot be adjusted for two connectors.

[0021] The bonding between the rigid board assembly and the single-sided flexible circuit board through the graphene silver paste composite conductive layer and the silver-based conductive adhesive layer solves the problems of unstable information transmission and large interference degree between wireless modules in the prior art.

[0022] On the above basis, the use of the rigid board assembly also brings some other beneficial effects. The rigid board assembly can be directly clamped in the backing plate, eliminating the risk of signal acquisition module offset due to equipment vibration during processing; and it can also solve the pain point that the wire sequence cannot be adjusted for two connectors. When the controller on the client side is docked, there is no need to adjust the wire sequence, saving development costs.

[0023] The bonding energy between the rigid board assembly and the single-sided flexible circuit board can prevent large deformations of both during thermal expansion. Most of the deformations are generated by the graphene silver paste composite conductive layer and the silver-based conductive adhesive layer, preventing problems such as cracking and deformation of the connection pins of the single-sided flexible circuit board, and taking into account both conductivity and medium-high temperature stability to meet the conductive and mechanical strength requirements under extreme high temperatures. The bonding between the rigid board assembly and the single-sided flexible circuit board saves the multi-point soldering process, ensures the overall structural strength of the single-sided flexible circuit board, can absorb mechanical stress during operation, and also reduces the risk of solder joint fatigue failure caused by vibration or impact.

[0024] For an electric vehicle battery pack, the internal space is limited. The above design not only reduces the connecting wire harness in the battery pack, but also improves the space utilization rate, which helps to achieve a battery system with higher energy density. It also realizes the real-time monitoring and control of the battery state, improves the thermal management efficiency of the battery system, and ensures the safety of the battery. Brief Description of the Drawings

[0025] 1 Backing plate, 2 Electrode series unit, 3 Copper-aluminum row, 4 Flexible board assembly

[0026] 11 Through hole, 12 Electrode groove, 13 Polarization groove, 14 Fixed column, 15 Metal sheet, 16 Channel

[0027] 21 Rigid board assembly, 22 Connection pin, 23 Rigid board groove, 24 PCB rigid board, 25 Acquisition hole, 26 Acquisition board, 41 Connector, 42 Single-sided flexible circuit board, 43 Double-sided flexible plug-in board

[0028] Figure 1 Schematic diagram of the overall structure of Embodiment 1;

[0029] Figure 2 Schematic diagram of the overall structure of the welding area of Embodiment 1;

[0030] Figure 3 Schematic diagram of the structure at the electrode series unit of Embodiment 1;

[0031] Figure 4 Schematic diagram of the structure at the electrode series unit on the backing plate of Embodiment 1;

[0032] Figure 5 Schematic diagram of the structure of the PCB rigid board of Embodiment 1;

[0033] Figure 6 Schematic diagram of the connection between the single-sided flexible circuit board and the copper-aluminum row of Embodiment 2; Detailed Description of the Invention

[0034] As Figure 1Embodiment 1 shown, a new type of CCS using a single-layer flexible board and multi-layer flexible combination technology, includes a flexible board assembly 4 and a backing plate 1 supporting the flexible board assembly 4. At least one end of the flexible board assembly 4 is installed with a connector 41, and the connector 41 hangs outside the area of the backing plate 1. The flexible board assembly 4 is a flexible printed circuit board (FPC), including a single-sided flexible circuit board 42 as the main board. At least one end of the single-sided flexible circuit board is provided with a connector 41, such as Figure 2 The connector 41 shown includes a double-sided flexible plug-in board 43 welded to the end of the single-sided flexible circuit board 42. The welding area is formed at the welding part of the double-sided flexible plug-in board 43 and the end of the single-sided flexible circuit board 42. A group of substrates 43 are arranged at the welding area to clamp and fix the welding area. The welding in this embodiment is hot-press tin soldering. First, solder paste is printed on the double-sided flexible plug-in board 43, and then heat is used to melt the solder and connect and conduct the single-sided flexible circuit board 42.

[0035] Such as Figure 3 and Figure 4 Shown in this embodiment, the backing plate 1 has several electrode series units 2. Preferably, the electrode series units 2 can be divided into 4 groups of electrode series groups. The four groups of electrode series groups are divided into two rows, and the electrode series groups on a straight line use a single-sided flexible circuit board 42. Therefore, two parallel single-sided flexible circuit boards 42 are used inside the backing plate 1 in this embodiment. Among them, several heat dissipation holes 13 are opened on the backing plate 1 below each single-sided flexible circuit board 42; and several fixed anchor bolts are evenly arranged on the backing plate 1 to fix the single-sided flexible circuit board 42.

[0036] In this embodiment, a rigid board assembly 21 for signal acquisition is arranged in one electrode series unit 2 in each group of electrode series groups.

[0037] The structure of the electrode series unit 2 without the rigid board assembly 21 in this electrode series group is: the electrode series unit 2 includes an electrode groove 12 formed by the upper surface of the backing plate 1 recessing downward to the lower surface for clamping the copper-aluminum row 3, and a copper-aluminum row 3 fitted in the electrode groove 12. Among them, the electrode groove 12 includes a polarizing groove 13 that recesses downward to the lower surface and transversely cuts the electrode groove 12, and the polarizing groove 13 cooperates with the convex strip on the copper-aluminum row 3; and a channel 16 extending from the backing plate 1 outside the electrode groove 12, in which a metal sheet 15 for connecting with the flexible board assembly 4 is arranged; it also includes two through holes 11 that are clamped with the battery pole and connected to the copper-aluminum row 3 and are located on both sides of the polarizing groove 13; and fixing columns 14 for fixing the copper-aluminum row 3 are arranged in the electrode groove 12 beside the through holes 11.

[0038] In the structure of the electrode series unit 2 containing the rigid board assembly 21, the electrode series unit 2 further includes a rigid board slot 23 located in the electrode slot 12 on one side of the polarization slot 13. The rigid board slot 23 is located in the electrode slot 12 on the other side of the channel 16, a PCB rigid board 24 fitted in the rigid board slot 23, and a collection hole 25 for placing a sensor device is provided in the rigid board slot 23, and the collection hole 25 penetrates through the PCB rigid board 24; holes are provided on the PCB rigid board 24 to cooperate with the fixing posts 14. As Figure 5 shown, two convex posts are provided on the PCB rigid board 24, and the two convex posts are respectively located on the PCB rigid board 24 at the end of the collection hole 25. A collection board 26 is fixed on the PCB rigid board 24, and through holes are provided on the collection board 26 to cooperate with the convex posts for fixing; the lower surface of the collection board 26 is connected to the sensor device through a graphene silver paste composite conductive layer, and the upper surface thereof is connected to the single-sided flexible circuit board 42 through a coated silver-based conductive adhesive layer. The single-sided flexible circuit board 42 bonded to the collection board 26 is also fixed on the convex posts. In this structure, the two connection parts of the rigid board assembly 21 respectively refer to one connected to the copper-aluminum row 3 by the PCB rigid board 24 and the other connected to the single-sided flexible circuit board 42. A graphene silver paste composite conductive layer is sprayed on the connection part, and a silver-based conductive adhesive layer is coated to form a connection pin 22. One connection pin 22 is connected to the copper-aluminum row 3 clamped in the electrode series unit 2, and the other connection pin 22 is connected to the single-sided flexible circuit board 42 fixed on the backing plate 1.

[0039] In this embodiment, a first interface is designed on the single-sided flexible circuit board 42 to be connected to the copper-aluminum row 3 through a metal sheet, a second interface is connected to the PCB rigid board 24, and a third interface is connected to the collection board 26. Among them, the first interface is welded to the metal sheet by laser. The second interface and the third interface are dried and connected by spraying a graphene silver paste composite conductive layer and coating a silver-based conductive adhesive layer. In another embodiment, the third interface can also be directly provided on the flexible circuit board body, and there is no need to design a protruding pin. Covering the collection board 26 through the flexible circuit board can shield some interference signals and make the temperature collection more accurate.

[0040] As Figure 6 shown in Embodiment 2, a graphene silver paste composite conductive layer is provided between the copper-aluminum row 3 and the single-sided flexible circuit board 42 and fixed through a silver-based conductive adhesive layer.

[0041] After eliminating a large number of laser weldings, by adjusting parameters such as the bonding pressure of the FPC and the uniformity of the adhesive layer, the yield target is increased to 95%. Moreover, in an environment of 200°C - 500°C, the conductivity (resistivity) ≤ 1×10 -4 Ω·cm, and the entire signal acquisition module is stable and accurate.

[0042] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0043] In this specification, unless otherwise clearly defined and limited, terms such as "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this specification can be understood according to specific circumstances.

[0044] In this specification, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature in terms of horizontal height. The first feature being "under", "beneath", and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature in terms of horizontal height.

[0045] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A novel CCS adopting a single-layer flexible board and multi-layer flexible combination technology, comprising a flexible board assembly (4) and a backing plate (1) supporting the flexible board assembly (4). At least one end of the flexible board assembly (4) is provided with a connector (41), and the connector (41) hangs outside the area of the backing plate (1). Characterized in that, The flexible board assembly (4) includes a single-sided flexible circuit board (42) serving as the main board. At least one end of the single-sided flexible circuit board is provided with a connector (41). The connector (41) includes a double-sided flexible plug-in board (43) welded to the end of the single-sided flexible circuit board (42). A welding area is formed at the welding position of the double-sided flexible plug-in board (43) and the end of the single-sided flexible circuit board (42). A group of substrates (43) is arranged in the welding area to clamp and fix the welding area.

2. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 1, wherein The backing plate (1) is provided with a number of electrode series units (2). The electrode series units (2) can be divided into at least 4 groups of electrode series groups. At least one of the electrode series units (2) in each group of electrode series groups is provided with a rigid board assembly (21) for signal acquisition. Among them, the rigid board assembly (21) has at least two connecting parts. A graphene silver paste composite conductive layer is sprayed on the connecting parts to form connecting pins (22). One of the connecting pins (22) is connected to a copper-aluminum row (3) clamped in the electrode series unit (2), and the other connecting pin (22) is connected to the single-sided flexible circuit board (42).

3. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 2, characterized in that, The connecting pin (22) needs to be coated with a silver-based conductive adhesive layer during installation.

4. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 3, characterized in that, The electrode series unit (2) includes an electrode groove (12) formed by the upper surface of the backing plate (1) recessing downward for clamping the copper-aluminum row (3), and the copper-aluminum row (3) embedded in the electrode groove (12).

5. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 4, characterized in that, The electrode groove (12) includes a dividing electrode groove (13) recessing downward and transversely cutting the electrode groove (12), and the dividing electrode groove (13) cooperates with the convex strip on the copper-aluminum row (3); and a channel (16) extending to the backing plate (1) outside the electrode groove (12), and a metal sheet (15) for connecting with the flexible board assembly (4) is arranged therein. It also includes two through holes (11) that are clamped with the battery pole and connected to the copper-aluminum row (3) and are located on both sides of the dividing electrode groove (13); and fixing columns (14) for fixing the copper-aluminum row (3) are arranged in the electrode groove (12) beside the through holes (11).

6. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 4, characterized in that, A graphene silver paste composite conductive layer is arranged between the copper-aluminum row (3) and the single-sided flexible circuit board (42), and is fixed through the silver-based conductive adhesive layer.

7. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 4 or 5 or 6, characterized in that, The electrode series unit (2) having the rigid board assembly (21) further includes a rigid board groove (23) in the electrode groove (12) on one side of the dividing electrode groove (13), and the rigid board groove (23) is in the electrode groove (12) on the other side of the channel (16). and a PCB rigid board (24) fitted in the rigid board groove (23), and a collection hole (25) for placing a sensor device is formed in the rigid board groove (23), and the collection hole (25) penetrates through the PCB rigid board (24); holes are formed in the PCB rigid board (24) to cooperate with the fixing posts (14).

8. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 5, wherein, At least one convex post is arranged on the PCB rigid board (24), and the convex post is located at the end of the collection hole (25); A collection board (26) is fixed on the PCB rigid board (24), the lower surface of the collection board (26) is connected with the sensor device through a graphene silver paste composite conductive layer, and the upper surface thereof is connected with the flexible board assembly (4) through a coated silver-based conductive adhesive layer, wherein the single-sided flexible circuit board (42) bonded to the collection board (26) is also fixed on the convex post.

9. The novel CCS adopting the single-layer flexible board and multi-layer flexible combination technology according to claim 1, characterized in that, The electrode series groups on a straight line adopt one single-sided flexible circuit board (42), and a plurality of heat dissipation holes (13) are formed in the backing plate (1) below the single-sided flexible circuit board (42); and a plurality of fixing anchor rods are uniformly arranged on the backing plate (1) to fix the single-sided flexible circuit board (42).

Images