Fuse structure and battery pack

Abstract

The invention discloses a fuse structure and a battery pack. The fuse structure comprises a printed circuit board 1, an etching fuse 2 arranged on the printed circuit board 1, a bonding pad 3 arranged on the printed circuit board 1 and connected with one end of the etching fuse 2, and a metal sheet 4 connected to the printed circuit board 1 and connected with the other end of the etching fuse 2, the upper layer of the printed circuit board 1 is a welding area, and the lower layer is an insulating material; the metal sheet 4 is bent into a step shape at a right angle, and the upper step is connected with the upper layer of the printed circuit board 1 and is connected with the etching fuse 2; and the lower step is flush with the bottom of the printed circuit board 1. The invention has the beneficial effects that the height is reduced, so that the product structure becomes compact; the lower layer of the printed circuit board is made of a hard insulating material, assembly is simple, and reliable insulation is ensured; the connection compatibility of the metal sheet and the battery pack aluminum bar is high, and the impedance is small; the mechanical strength is high and the service life is long; the production cost is low.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a fuse structure and a battery pack. Background Art

[0002] At present, new energy vehicles are developing rapidly, and power batteries are inevitably used in new energy vehicles. At present, the safety of power batteries is an important issue. The current integrated busbar (Cells Contact System, referred to as CCS) uses a flexible printed circuit (Flexible Printed Circuit, referred to as FPC) to collect and transmit electrical signals such as voltage, current, and temperature, and integrates fuses on FPC. Because the fuse function can be easily realized on FPC, but the cost of FPC is relatively high.

[0003] When a low-cost flexible flat cable (FFC) or wiring harness is used to collect and transmit electrical signals, fuses cannot be integrated, and the entire CCS has no fuse function. The thermal management of the battery pack lacks safety protection, and when the current is abnormal, the circuit cannot be cut off in time.

[0004] If a fuse is to be installed on the FFC, the structure and material of the fuse need to be improved because the installation structure requires to be very compact.

[0005] Therefore, it is urgent to develop a fuse structure and battery pack that is compact, easy to assemble, safe and reliable. Summary of the invention

[0006] This application aims to solve the above technical problems.

[0007] To this end, the first object of the present application is to provide a fuse structure that is compact, easy to assemble, safe and reliable.

[0008] The second objective of the present application is to provide a battery pack.

[0009] To achieve the above-mentioned purpose, an embodiment of the present application discloses a fuse structure, comprising a printed circuit board 1, an etched fuse 2 arranged on the printed circuit board 1, a solder pad 3 arranged on the printed circuit board 1 and connected to one end of the etched fuse 2, and a metal sheet 4 connected to the printed circuit board 1 and connected to the other end of the etched fuse 2; wherein the upper layer of the printed circuit board 1 is a welding area, and the lower layer is a hard or soft insulating material; the metal sheet 4 is bent at a right angle into a step shape, the upper step is connected to the upper layer of the printed circuit board 1 and to the etched fuse 2; and the lower step is flush with the bottom of the printed circuit board 1.

[0010] In addition, the fuse structure according to the above technical solution of the present application may also have the following additional technical features: Optionally, the printed circuit board 1 is connected to the metal sheet 4 by surface mounting or soldering iron or laser welding process.

[0011] Optionally, a tin-through hole 5 is provided at the connection between the metal sheet 4 and the printed circuit board 1 .

[0012] To achieve the above-mentioned purpose, a second embodiment of the present application proposes a battery pack, including a fuse structure as proposed in the first embodiment of the present application.

[0013] The beneficial effects of the present application are: 1. Etching a fuse in the printed circuit board reduces the height and makes the product structure compact; 2. The lower layer of the printed circuit board is a hard insulating material, which is easy to assemble and ensures reliable insulation; 3. The metal sheet and the battery pack aluminum bar connection are highly compatible and have low impedance; 4. High mechanical strength and long life; 5. Low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a three-dimensional diagram of a fuse structure provided by an embodiment of the present application; Figure 2 is a design diagram of a fuse structure provided by an embodiment of the present application, wherein Figure 2 (a) is the main view, Figure 2 (b) is a bottom view. Figure 2 (a) is a stereogram.

[0015] Reference numerals: 1-printed circuit board, 2-etched fuse, 3-soldering pad, 4-metal sheet, 5-tin-through hole. DETAILED DESCRIPTION

[0016] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or components / elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0017] The fuse structure of the embodiment of the present application is described below with reference to the accompanying drawings.

[0018] Figure 1 is a three-dimensional diagram of a fuse structure provided by an embodiment of the present application; Figure 2 is a design diagram of a fuse structure provided by an embodiment of the present application, wherein Figure 2 (a) is the main view, Figure 2 (b) is a bottom view. Figure 2(a) is a stereogram. Figure 1-2 As shown: the fuse structure includes a printed circuit board 1, an etched fuse 2 arranged on the printed circuit board 1, a solder pad 3 arranged on the printed circuit board 1 and connected to one end of the etched fuse 2, and a metal sheet 4 connected to the printed circuit board 1 and connected to the other end of the etched fuse 2; wherein the upper layer of the printed circuit board 1 is a welding area, and the lower layer is a hard or soft insulating material; the metal sheet 4 is bent at a right angle into a step shape, the upper step is connected to the upper layer of the printed circuit board 1 and to the etched fuse 2; the lower step is flush with the bottom of the printed circuit board 1.

[0019] Specifically, the metal sheet 4 is a metal material, usually nickel, steel, aluminum, copper sheet and other metal materials, which can be welded to materials such as battery pack aluminum bar. This material selection can make the welding compatibility of the metal sheet 4 and the battery pack aluminum bar better, reduce the interface impedance, and improve the current transmission stability; the circuit board 1 is a hard printed circuit board material, the upper layer is a pad, that is, a welding area, which can be welded to components such as FFC or wiring harness, and the lower layer is an insulating material of the hard printed circuit board to ensure insulation from the aluminum bar below or other metal structures of the battery pack. It can be directly placed or adhered to components such as aluminum bar with double-sided tape. The insulating material of the printed circuit board provides mechanical support to avoid connection failure caused by deformation of the flexible material, and at the same time keeps the printed circuit board insulated from the aluminum bar or other components below; the lower layer of the printed circuit board can also be made of soft material according to the design requirements of the battery pack, such as when a buffer function is required; the pad 3 is a material with a bare copper surface or a tin-plated surface, which can be welded to components such as FFC or wiring harnesses, and the welding connection is convenient and reliable; the fuse 2 is a thin circuit etched by the FPC process, which acts as a fuse according to different current fusing requirements, and can be blown here when the current is abnormal.

[0020] First, the design of the lower step flush with the PCB can directly fit the battery pack aluminum bar or module shell, avoiding the extra space occupied by traditional vertical welding, realizing a bracket-free CCS structure, eliminating the bracket components for fixing metal sheets in traditional CCS, reducing the number of parts and assembly complexity. This makes the product space adaptable. This design can save 5~8mm of vertical space for the product.

[0021] Secondly, the mechanical stability is good: the metal sheet forms a physical interlocking structure through right-angle bending, and the structure is relatively stable; in terms of impact resistance, the structure of the lower step flush with the bottom of the PCB makes the metal sheet and the PCB form an "L"-shaped support to resist high-frequency vibration during battery pack operation (such as bumpy conditions of new energy vehicles) and prevent fatigue fracture of solder joints (compared with the unbent cantilever structure); in terms of welding strength, the connection point between the upper step and the upper layer of the PCB is directly welded to the etched fuse, and the contact surface between the lower step and the aluminum bar is fixed by laser welding or riveting to form a double anchor point, reducing the risk of single-point failure; and the lower step of the metal sheet is flush with the bottom of the PCB, achieving large-area contact with the aluminum bar. The aluminum bar is generally a flat structure, connected to the metal sheet on one side and supporting the printed circuit board on the other side, without adding other components, or designing the aluminum bar as an uneven structure. The vibration test results show that the life of this fuse structure is increased by about 3 times.

[0022] Finally, the metal sheet can be formed in one step through the stamping process, which is simple to process. In addition, the metal sheet is preformed into a step structure, which can be directly positioned during SMT welding to avoid the precision error caused by on-site bending. The entire FFC production and processing cost is reduced by about 15%~20%.

[0023] According to the fuse structure of the present application, the fuse is made directly on the printed circuit board through the etching process (rather than the dedicated process of FPC), which further simplifies the manufacturing process and reduces production costs; allows the use of FFC or ordinary wiring harness as a signal transmission carrier, breaking through the traditional FPC's dependence on fuse integration; the line width, thickness and shape of the fuse can be precisely controlled through the etching process to achieve a fast fuse response to a specific current value. Compared with traditional alloy fuses, the geometric parameters of the etching line are more adjustable and can meet the diverse overcurrent protection needs of the battery pack; the rigid printed circuit board provides mechanical support while also having an insulating effect, saving intermediate materials.

[0024] According to an embodiment of the present application, the printed circuit board 1 and the metal sheet 4 are connected by surface mounting technology (SMT) or soldering iron or laser welding process.

[0025] Specifically, the SMT process can be used to connect the metal sheet 4 to the printed circuit board 1, which can effectively reduce the size of the product and save production costs. Laser welding can also be used for connection, because laser welding has a small heat-affected zone, rapid heating concentration, and low thermal stress. Traditional electric soldering iron welding or other methods can also be used for connection.

[0026] According to an embodiment of the present application, a tin-through hole 5 is provided at the connection between the metal sheet 4 and the printed circuit board 1 .

[0027] Specifically, when the metal sheet is welded to the aluminum bar, the solder can penetrate easily to ensure reliable welding; and the hole can also discharge the gas generated during welding to ensure reliable welding connection.

[0028] Based on the above embodiments, an embodiment of the present invention further proposes a battery pack, including: a fuse structure as in the above embodiments.

[0029] According to a battery pack of the present application, the fuse structure therein is made by directly manufacturing the fuse on the printed circuit board through an etching process (rather than a dedicated process for FPC), which further simplifies the manufacturing process and reduces production costs; allows the use of FFC or ordinary wiring harness as a signal transmission carrier, breaking through the traditional FPC's dependence on fuse integration; the line width, thickness and shape of the fuse can be precisely controlled through the etching process to achieve a fast fusing response to a specific current value. Compared with traditional alloy fuses, the geometric parameters of the etching circuit are more adjustable and can meet the diverse overcurrent protection needs of the battery pack; the rigid printed circuit board provides mechanical support while also having an insulating effect, saving intermediate materials.

[0030] The above embodiments are preferred implementation schemes of the present application. In addition, the present application may also be implemented in other ways. Any obvious replacement without departing from the concept of the present application is within the protection scope of the present application.

Claims

1. A fuse structure, characterized in that: include: A printed circuit board (1), an etched fuse (2) arranged on the printed circuit board (1), a solder pad (3) arranged on the printed circuit board (1) and connected to one end of the etched fuse (2), and a metal sheet (4) connected to the printed circuit board (1) and connected to the other end of the etched fuse (2); The upper layer of the printed circuit board (1) is a welding area, and the lower layer is a hard or soft insulating material; The metal sheet (4) is bent at a right angle into a step shape, the upper step is connected to the upper layer of the printed circuit board (1) and to the etched fuse (2); the lower step is flush with the bottom of the printed circuit board (1).

2. A fuse structure according to claim 1, characterized in that: The printed circuit board (1) and the metal sheet (4) are connected via surface mounting or soldering iron or laser welding process.

3. A fuse structure according to claim 1, characterized in that: A tin-penetrating hole (5) is provided at the connection between the metal sheet (4) and the printed circuit board (1).

4. A battery pack, characterized in that: It comprises a wiring harness integrated busbar structure with a fuse as described in any one of claims 1 to 3.

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