BMS MOSFET module packaging structure based on ceramic substrate

Abstract

The utility model discloses a BMS (Battery Management System) MOSFET (Metal Oxide Semiconductor Field Effect Transistor) module packaging structure based on a ceramic substrate. According to the scheme, the ceramic substrate is adopted to replace a PCB, and the ceramic substrate is high in heat conductivity and good in insulativity. The chip is directly welded on the copper layer of the ceramic substrate through the soldering paste, the adverse effect of black glue is avoided, the metal copper sheet is arranged above the chip, the heat dissipation path is increased, and double-face heat dissipation is achieved. Meanwhile, terminal connection and heat dissipation gaps among parts are optimally designed and filled with heat conduction gel, so that the heat dissipation efficiency is effectively improved, stable operation of the module is ensured, the service life is prolonged, and the efficient heat dissipation requirement of electronic equipment is met.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor packaging, especially relates to a BMS MOSFET module packaging structure based on ceramic substrate. BACKGROUND

[0002] In the battery management system (BMS), the traditional BMS MOSFET array module packaging structure usually adopts laminated design, mainly by chip, solder layer, printed circuit board (PCB), heat-conducting gel and heat dissipation bottom plate are constituted. Chip is mostly MOSFET chip after TOLL (TOLL) package, is connected with external circuit through pin and is welded to PCB pad. However, this traditional structure has many disadvantages.

[0003] In terms of heat dissipation, MOSFET chip will produce huge power loss when charging and discharging control and short-circuit protection of BMS module, and the heat dissipation requirement is extremely high. But the heat transfer path of traditional packaging depends on from the inside of the chip to the solder layer through the packaging material, and then to the heat-conducting gel and the heat sink through the PCB board with poor heat-conducting performance (its thickness direction heat-conducting coefficient is even lower than 0.5 W / m·K), and finally to the air. Moreover, the heat-conducting ability of the black glue of chip packaging is poor, and heat is easy to accumulate in the inside of the chip, so that the overall heat dissipation performance is seriously insufficient, which greatly affects the working stability and service life of MOSFET chip, and cannot meet the demand of modern electronic equipment for high-efficiency heat dissipation. SUMMARY

[0004] The utility model aims at providing a BMS MOSFET module packaging structure based on ceramic substrate, to solve the problem of poor heat dissipation performance of traditional BMS MOSFET array module packaging structure, improve the reliability and stability of the module, and ensure its efficient operation in various electronic equipment.

[0005] The utility model realizes the following technical scheme:

[0006] A BMS MOSFET module packaging structure based on ceramic substrate, comprising a heat dissipation bottom plate and a heat-conducting gel provided on the heat dissipation bottom plate,

[0007] From the heat dissipation bottom plate to the heat-conducting gel, the heat dissipation bottom plate is further provided with a first solder layer, a first lower copper layer and a ceramic substrate in sequence,

[0008] In the direction from the heat dissipation base plate to the second upper copper layer, the second upper copper layer is sequentially provided with a third solder layer, a first MOSFET chip, a fourth solder layer and a metal copper sheet, and the third upper copper layer is sequentially provided with a fifth solder layer, a second MOSFET chip and a sixth solder layer; one end of the fourth solder layer is connected to the first MOSFET chip, and the other end of the fourth solder layer is connected to the metal copper sheet; one end of the sixth solder layer is connected to the second MOSFET chip, and the other end of the sixth solder layer is also connected to the metal copper sheet.

[0009] The heat dissipation base plate is further provided with a first terminal and a second terminal.

[0010] Preferably, one end of the first terminal is connected to the heat dissipation base plate, and the other end of the first terminal is provided with a first protruding part, and a second solder layer connecting the first protruding part and the second upper copper layer is arranged between the first protruding part and the second upper copper layer; one end of the second terminal is connected to the heat dissipation base plate, and the other end of the second terminal is provided with a second protruding part, and a seventh solder layer connecting the second protruding part and the third upper copper layer is arranged between the second protruding part and the third upper copper layer.

[0011] Preferably, the first terminal is respectively left with a heat dissipation gap between the first solder layer, the first lower copper layer, the ceramic substrate, the second upper copper layer and the second solder layer; and the heat dissipation gap is filled with a heat-conducting gel.

[0012] Preferably, the second terminal is respectively left with a heat dissipation gap between the first solder layer, the first lower copper layer, the ceramic substrate, the third upper copper layer and the seventh solder layer; and the heat dissipation gap is filled with a heat-conducting gel.

[0013] Preferably, the first terminal is respectively left with a heat dissipation gap between the third solder layer, the first MOSFET chip and the fourth solder layer, and the second solder layer is respectively left with a heat dissipation gap between the third solder layer, the first MOSFET chip and the fourth solder layer; and the heat dissipation gap is filled with a heat-conducting gel.

[0014] Preferably, the second terminal is respectively left with a heat dissipation gap between the fifth solder layer, the second MOSFET chip and the sixth solder layer, and the seventh solder layer is respectively left with a heat dissipation gap between the fifth solder layer, the second MOSFET chip and the sixth solder layer; and the heat dissipation gap is filled with a heat-conducting gel.

[0015] Preferably, the fourth solder layer, the first MOSFET chip and the third solder layer are respectively left with a heat dissipation gap between the sixth solder layer, the second MOSFET chip and the fifth solder layer; and the heat dissipation gap is filled with a heat-conducting gel.

[0016] Preferably, a heat dissipation gap is left between the second upper copper layer and the third upper copper layer, and the heat dissipation gap is filled with heat-conducting gel.

[0017] Preferably, along a direction from the heat dissipation base plate to the metal copper sheet, a vertical distance between an upper wall of the metal copper sheet and an upper wall of the heat dissipation base plate is L1, a vertical distance between an upper surface of the heat-conducting gel and the upper wall of the heat dissipation base plate is L2, and L1>L2 is satisfied.

[0018] Preferably, along a direction from the heat dissipation base plate to the metal copper sheet, the first terminal and the second terminal are arranged in an inclined manner, and an axis of the first terminal and an axis of the second terminal intersect above the heat dissipation base plate.

[0019] Compared with the prior art, the utility model has the following advantages and beneficial effects: the utility model adopts ceramic substrate to replace traditional PCB board, and high thermal conductivity and good insulation of the ceramic substrate provide powerful guarantee for heat dissipation. The chip is directly welded on the copper layer of the ceramic substrate through solder paste, heat is avoided from being transmitted through black glue with poor heat conduction, a metal copper sheet is arranged above the chip to increase a heat dissipation path, double-sided heat dissipation is realized, heat dissipation efficiency is greatly improved, stable work of the MOSFET chip under high power loss is ensured, service life is prolonged, and the demand of modern electronic equipment is met. BRIEF DESCRIPTION OF DRAWINGS

[0020] The drawings described herein are used to provide further understanding of the embodiments of the utility model and form part of the application, and do not constitute limitation to the embodiments of the utility model. In the drawings:

[0021] Figure 1 It is a traditional BMS MOSFET array module packaging structure schematic diagram;

[0022] Figure 2 It is a BMS MOSFET array module packaging structure based on ceramic substrate of the utility model.

[0023] The represented by the reference signs is:

[0024] 10, heat dissipation base plate, 11, first terminal, 12, second terminal, 13, first solder layer, 14, first lower copper layer, 15, ceramic substrate, 16, second upper copper layer, 17, second solder layer, 18, third solder layer, 19, first MOSFET chip,

[0025] 20, fourth solder layer, 21, metal copper sheet, 22, third upper copper layer, 23, fifth solder layer, 24, second MOSFET chip, 25, sixth solder layer, 26, seventh solder layer, 27, heat-conducting gel. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by persons skilled in the art to which the present application belongs. The "first", "second" and similar words used in the present application do not represent any order, quantity or importance, but are only used to distinguish different components. The words such as "include" or "contain" mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, and do not exclude other elements or objects.

[0027] In the BMS module, the MOSFET chip has large power consumption and high heat dissipation requirement during charging and discharging and short circuit protection. In the traditional packaging, heat is transferred through the chip packaging material, solder layer, PCB board (low thermal conductivity), heat-conducting gel to the heat sink, and the chip black glue has poor heat conduction and is easy to accumulate heat, which affects the stability and service life of the chip and cannot meet the heat dissipation requirements of modern equipment.

[0028] Embodiment 1:

[0029] As Figure 1 is a traditional BMS MOSFET array module packaging structure, which adopts a layered structure, and the chip is TOLL packaged and then soldered to the PCB pad and connected to the external circuit through the pin. In terms of heat dissipation, when the chip works and generates a large power loss, the heat transfer path needs to pass through the chip packaging material, the solder layer, and then the PCB board with poor heat conduction (the thickness direction thermal conductivity is less than 0.5 W / m·K), and finally to the heat-conducting gel 27 and the heat sink. The chip packaging black glue has poor heat conduction and is easy to accumulate heat, which seriously depends on the characteristics of the PCB board, and the overall heat dissipation performance is insufficient, which affects the reliability of the chip and the performance of the product.

[0030] As Figure 2The embodiment provides a BMS MOSFET array module packaging structure based on a ceramic substrate 15, which comprises a heat dissipation base plate 10 and heat-conducting gel 27 arranged on the heat dissipation base plate 10, and from the heat dissipation base plate 10 to the heat-conducting gel 27, the heat dissipation base plate 10 is sequentially provided with a first solder layer 13, a first lower copper layer 14, the ceramic substrate 15, the ceramic substrate 15 is provided with a second upper copper layer 16 and a third upper copper layer 22; from the heat dissipation base plate 10 to the second upper copper layer 16, the second upper copper layer 16 is sequentially provided with a third solder layer 18, a first MOSFET chip 19, a fourth solder layer 20 and a metal copper sheet 21, the third upper copper layer 22 is sequentially provided with a fifth solder layer 23, a second MOSFET chip 24 and a sixth solder layer 25; one end of the fourth solder layer 20 is connected to the first MOSFET chip 19, the other end of the fourth solder layer 20 is connected to the metal copper sheet 21, one end of the sixth solder layer 25 is connected to the second MOSFET chip 24, and the other end of the sixth solder layer 25 is also connected to the metal copper sheet 21; the heat dissipation base plate 10 is further provided with a first terminal 11 and a second terminal 12.

[0031] The scheme aims to solve the problem of poor heat dissipation performance of a traditional BMS MOSFET array module packaging structure. In the scheme, the ceramic substrate 15 is a key component, which has high thermal conductivity and good insulation. The working principle is as follows: in actual application, when the MOSFET chip works and generates heat, the heat can be quickly transmitted to the copper layer on the ceramic substrate 15 through the solder layer below the chip, and the high thermal conductivity of the ceramic substrate 15 enables the heat to be quickly dispersed. At the same time, the metal copper sheet 21 above the chip is connected to the chip through the solder layer, forming another heat dissipation path, realizing double-sided heat dissipation, greatly improving the heat dissipation efficiency, ensuring the stable operation of the MOSFET chip, prolonging its service life, and meeting the demand of electronic equipment for high-efficiency heat dissipation.

[0032] In the embodiment, one end of the first terminal 11 is connected to the heat dissipation base plate 10, the other end of the first terminal 11 is provided with a first protruding part, and the second solder layer 17 connecting the first protruding part and the second upper copper layer 16 is arranged between the first protruding part and the second upper copper layer 16; one end of the second terminal 12 is connected to the heat dissipation base plate 10, the other end of the second terminal 12 is provided with a second protruding part, and the seventh solder layer 26 connecting the second protruding part and the third upper copper layer 22 is arranged between the second protruding part and the third upper copper layer 22.

[0033] The terminal plays an electrical connection role, one end of the first terminal 11 is connected to the heat dissipation base plate 10, the protruding part thereof is connected to the second upper copper layer 16 through the second solder layer 17, and the second terminal 12 is the same. While ensuring electrical transmission, the heat dissipation gap is arranged at each connection position and filled with the heat-conducting gel 27, so that the heat dissipation effect around the terminal is effectively improved, and the heat can be better dissipated.

[0034] In this embodiment, the first terminal 11 leaves a heat dissipation gap between the first solder layer 13, the first lower copper layer 14, the ceramic substrate 15, the second upper copper layer 16 and the second solder layer 17 respectively; the heat dissipation gap is filled with the heat-conducting gel 27.

[0035] After the heat dissipation gap between the first terminal 11 and each layer structure is filled with the heat-conducting gel 27, when heat is generated, the heat-conducting gel 27 can absorb and conduct heat, so that the heat is evenly dispersed among different layer structures, avoiding local overheating and enhancing the overall heat dissipation capacity.

[0036] In this embodiment, the second terminal 12 leaves a heat dissipation gap between the first solder layer 13, the first lower copper layer 14, the ceramic substrate 15, the third upper copper layer 22 and the seventh solder layer 26 respectively; the heat dissipation gap is filled with the heat-conducting gel 27.

[0037] The heat-conducting gel 27 in the heat dissipation gap can effectively transfer heat, ensuring that the heat near the second terminal 12 is promptly dissipated, and cooperating with the heat dissipation at the first terminal 11, further optimizing the overall heat dissipation system of the module.

[0038] In this embodiment, the first terminal 11 leaves a heat dissipation gap between the third solder layer 18, the first MOSFET chip 19 and the fourth solder layer 20 respectively, and the second solder layer 17 leaves a heat dissipation gap between the third solder layer 18, the first MOSFET chip 19 and the fourth solder layer 20 respectively; the heat dissipation gap is filled with the heat-conducting gel 27.

[0039] The heat dissipation gap between the first terminal 11 and the third solder layer 18, the first MOSFET chip 19 and the fourth solder layer 20 is filled with the heat-conducting gel 27, and the heat dissipation gap between the second solder layer 17 and these components is the same. When the chip works and generates heat, the heat-conducting gel 27 conducts heat in these gaps, avoiding heat accumulation around the chip, effectively reducing the temperature of the chip.

[0040] In this embodiment, the second terminal 12 leaves a heat dissipation gap between the fifth solder layer 23, the second MOSFET chip 24 and the sixth solder layer 25 respectively, and the seventh solder layer 26 leaves a heat dissipation gap between the fifth solder layer 23, the second MOSFET chip 24 and the sixth solder layer 25 respectively; the heat dissipation gap is filled with the heat-conducting gel 27.

[0041] The heat dissipation gap enables heat to be evenly dispersed among these components, preventing local overheating from affecting the performance of the chip and ensuring the stability of the electrical performance of the entire BMS MOSFET array module.

[0042] In this embodiment, the fourth solder layer 20, the first MOSFET chip 19 and the third solder layer 18 leave a heat dissipation gap between the sixth solder layer 25, the second MOSFET chip 24 and the fifth solder layer 23 respectively; the heat dissipation gap is filled with the heat-conducting gel 27.

[0043] The heat dissipation gap facilitates heat exchange between different chips and solder layers, improves overall heat dissipation efficiency, and maintains temperature balance inside the module.

[0044] In this embodiment, a heat dissipation gap is left between the second upper copper layer 16 and the third upper copper layer 22, and the heat dissipation gap is filled with the heat-conducting gel 27.

[0045] When heat is transferred to the heat-conducting gel 27, the heat-conducting gel 27 disperses the heat, prevents the heat from accumulating between the two layers, optimizes the heat dissipation path of the module, and enables the heat to be more smoothly conducted out.

[0046] The packaging steps are as follows:

[0047] The packaging steps are as follows:

[0048] Direct bonding of copper: heat the copper metal in a high-temperature environment of 1065-1085℃ to bond it with the upper and lower surfaces of the ceramic substrate 15 to form a ceramic copper-clad plate (DBC).

[0049] Etching of the upper copper layer: expose and develop the upper copper layer of the DBC according to the circuit design, and perform chemical etching to generate specific patterns and lines.

[0050] First soldering: print solder paste on the surface of the upper copper layer of the DBC, mount the MOSFET chips, and solder the chip pins to the upper copper layer pads. The chips are arranged in an array.

[0051] Second soldering: print solder paste on the surface of the MOSFET chips, and mount the metal copper sheet 21.

[0052] Shell plastic packaging: glue the shell, print solder paste on the surface of the lower copper layer of the DBC, and mount the heat dissipation metal copper bottom plate.

[0053] Shell glue filling and solidification: inject the heat-conducting gel 27 into the shell and vacuumize, and solidify at a high temperature of about 110-130℃. The heat-conducting gel 27 does not completely cover the topmost metal copper sheet 21.

[0054] Packaging and terminal shaping: install the top cover and mount the terminals on the surface of the solder paste to complete the overall packaging.

[0055] Embodiment 2:

[0056] On the basis of the embodiment, in this embodiment, the vertical distance between the upper wall of the metal copper sheet 21 and the upper wall of the heat dissipation bottom plate 10 in the direction from the heat dissipation bottom plate 10 to the metal copper sheet 21 is L1, the vertical distance between the upper surface of the heat-conducting gel 27 and the upper wall of the heat dissipation bottom plate 10 is L2, and L1>L2 is satisfied.

[0057] The vertical distance L1 between the upper wall of the metal copper sheet 21 and the upper wall of the heat dissipation base plate 10 is greater than the vertical distance L2 between the upper surface of the heat conductive gel 27 and the upper wall of the heat dissipation base plate 10, so that the metal copper sheet 21 can fully play a role in heat dissipation and is not completely covered by the heat conductive gel 27, the heat dissipation advantage of the metal copper sheet 21 is maintained, the overall heat dissipation effect of the BMS MOSFET array module is effectively improved, and efficient operation of the module is ensured.

[0058] In the embodiment, the first terminal 11 and the second terminal 12 are arranged in an inclined manner along the direction from the heat dissipation base plate 10 to the metal copper sheet 21, and the axis of the first terminal 11 and the axis of the second terminal 12 intersect above the heat dissipation base plate 10.

[0059] The layout can optimize the electrical connection path, reduce electromagnetic interference, and improve the heat dissipation airflow channel, so that heat is dissipated more smoothly, the comprehensive performance of the BMS MOSFET array module is improved, and stable operation of the BMS MOSFET array module in a complex environment is ensured.

[0060] The above embodiments are only used to illustrate the technical solutions of the present disclosure, but not limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure. The following points need to be explained: only the structures related to the embodiments of the present disclosure are involved in the embodiment drawings of the present disclosure, and other structures can be referred to the usual design. In the case of no conflict, the features in the same embodiment and different embodiments of the present disclosure can be combined with each other. The above description is only a demonstrative embodiment of the present disclosure, but not used to limit the protection scope of the present disclosure, the protection scope of the present disclosure is determined by the appended claims.

Claims

1. A BMS MOSFET module packaging structure based on ceramic substrate, comprising a heat dissipation base plate (10) and a heat conductive gel (27) arranged on the heat dissipation base plate (10), characterized in that, from the heat dissipation base plate (10) to the heat conductive gel (27), the heat dissipation base plate (10) is further sequentially provided with a first solder layer (13), a first lower copper layer (14), a ceramic substrate (15), and the ceramic substrate (15) is provided with a second upper copper layer (16) and a third upper copper layer (22); from the heat dissipation base plate (10) to the second upper copper layer (16), the second upper copper layer (16) is sequentially provided with a third solder layer (18), a first MOSFET chip (19), a fourth solder layer (20) and a metal copper sheet (21), and the third upper copper layer (22) is sequentially provided with a fifth solder layer (23), a second MOSFET chip (24) and a sixth solder layer (25); one end of the fourth solder layer (20) is connected to the first MOSFET chip (19), the other end of the fourth solder layer (20) is connected to the metal copper sheet (21), one end of the sixth solder layer (25) is connected to the second MOSFET chip (24), and the other end of the sixth solder layer (25) is also connected to the metal copper sheet (21); the heat dissipation base plate (10) is further provided with a first terminal (11) and a second terminal (12).

2. The ceramic substrate based BMS MOSFET module package structure of claim 1, wherein, one end of the first terminal (11) is connected to the heat dissipation base plate (10), the other end of the first terminal (11) is provided with a first protruding part, and a second solder layer (17) connecting the first protruding part and the second upper copper layer (16) is arranged between the first protruding part and the second upper copper layer (16); one end of the second terminal (12) is connected to the heat dissipation base plate (10), the other end of the second terminal (12) is provided with a second protruding part, and a seventh solder layer (26) connecting the second protruding part and the third upper copper layer (22) is arranged between the second protruding part and the third upper copper layer (22).

3. The ceramic substrate based BMS MOSFET module package structure of claim 2, wherein, the first terminal (11) is respectively provided with a heat dissipation gap between the first solder layer (13), the first lower copper layer (14), the ceramic substrate (15), the second upper copper layer (16) and the second solder layer (17).

4. The ceramic substrate based BMS MOSFET module package structure of claim 3, wherein, the second terminal (12) is respectively provided with a heat dissipation gap between the first solder layer (13), the first lower copper layer (14), the ceramic substrate (15), the third upper copper layer (22) and the seventh solder layer (26).

5. The ceramic substrate based BMS MOSFET module package structure of claim 4, wherein, the first terminal (11) is respectively provided with a heat dissipation gap between the third solder layer (18), the first MOSFET chip (19) and the fourth solder layer (20), and the second solder layer (17) is respectively provided with a heat dissipation gap between the third solder layer (18), the first MOSFET chip (19) and the fourth solder layer (20).

6. The ceramic substrate based BMS MOSFET module package structure of claim 5, wherein, The second terminal (12) is respectively left with a heat dissipation gap between the fifth solder layer (23), the second MOSFET chip (24) and the sixth solder layer (25), and the seventh solder layer (26) is respectively left with a heat dissipation gap between the fifth solder layer (23), the second MOSFET chip (24) and the sixth solder layer (25).

7. The ceramic substrate based BMS MOSFET module package structure of claim 6, wherein, The fourth solder layer (20), the first MOSFET chip (19) and the third solder layer (18) are respectively left with a heat dissipation gap between the sixth solder layer (25), the second MOSFET chip (24) and the fifth solder layer (23).

8. The ceramic substrate based BMS MOSFET module package structure of claim 7, wherein, A heat dissipation gap is left between the second upper copper layer (16) and the third upper copper layer (22), and the heat dissipation gap is filled with a heat-conducting gel (27).

9. The ceramic substrate based BMS MOSFET module package structure of claim 8, wherein, In the direction from the heat dissipation bottom plate (10) to the metal copper sheet (21), the vertical distance between the upper wall of the metal copper sheet (21) and the upper wall of the heat dissipation bottom plate (10) is L1, the vertical distance between the upper surface of the heat-conducting gel (27) and the upper wall of the heat dissipation bottom plate (10) is L2, and L1>L2 is satisfied.

10. A ceramic substrate based BMS MOSFET module package structure according to any one of claims 1-9, wherein, In the direction from the heat dissipation bottom plate (10) to the metal copper sheet (21), the first terminal (11) and the second terminal (12) are arranged in an inclined manner, and the axis of the first terminal (11) intersects the axis of the second terminal (12) above the heat dissipation bottom plate (10).

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