Shunt resistor-based busbar current detection module

Abstract

The invention relates to the technical field of busbar current detection, and discloses a shunt resistor-based busbar current detection module, which comprises a busbar substrate, a copper plane formed through a CGDS technology, a shunt resistor and a PCB (Printed Circuit Board), the busbar substrate is provided with a groove, and the copper plane at least comprises copper terminals formed at the two ends of the busbar substrate in the length direction and a second copper plane formed at the upper end of the groove. The shading resistor is arranged on the second copper plane; a signal processing chip is carried on the PCB, and the PCB is electrically connected with the shunt resistor so as to obtain potential difference signals at the two ends of the shunt resistor. Manganese-copper-tin alloy is used as a Shunt resistance material, and the resistance value fluctuation caused by temperature change is effectively reduced by using the extremely low temperature coefficient of the manganese-copper-tin alloy, so that high-precision current measurement is realized in a large-current detection scene.

Description

Technical Field

[0001] This invention relates to the field of bus current detection technology, specifically a bus current detection module based on a shunt resistor. Background Technology

[0002] Driven by both the new energy revolution and the intelligent upgrading of industry, power electronics and automotive electronics have become core tracks for global technological innovation. The former supports the energy conversion efficiency of key equipment such as photovoltaic inverters, energy storage converters, and industrial servo systems, while the latter directly determines the safety performance and range of the three core components (battery, motor, and electronic control) of new energy vehicles. In these two fields, high-precision current detection is crucial. For new energy vehicles, the battery management system (BMS) needs to accurately detect charging and discharging currents to avoid battery life degradation or safety risks caused by overcharging and over-discharging. For industrial servo systems, the accuracy of current detection directly affects the stability of motor torque control; if the error exceeds 1%, it may lead to excessive positioning deviations in precision machining equipment.

[0003] To address these needs, two main approaches exist: first, the shunt resistor solution, which calculates current by detecting the voltage across the resistor. While low-cost, this approach suffers from insertion loss—in high-power scenarios, resistor heating increases energy efficiency by 5%-8%, and it's difficult to adapt to high-frequency current sensing; second, the Hall effect solution, while achieving non-contact detection, suffers from large temperature drift and slow response speed (microseconds), failing to meet the requirements of next-generation high-frequency power electronic equipment. In contrast, the tunnel magnetoresistive (TMR) effect current sensing solution has become the mainstream choice in the industry.

[0004] However, while TMR elements have extremely high magnetic sensitivity, this also makes them exceptionally sensitive to ambient magnetic fields. In the motor compartment of new energy vehicles, high-voltage wiring harnesses, motor stator windings, DC / DC converters, and other equipment generate complex alternating magnetic fields. These external magnetic fields superimpose with the target magnetic field generated by the bus current, causing the TMR element's output signal to drift. Secondly, the stringent assembly requirements create production and cost pressures. The detection accuracy of TMR elements is highly dependent on the precise alignment of the air gap center of the magnetic core. An axial deviation exceeding 0.1mm or an angular deviation exceeding 1° will lead to magnetic flux detection errors. Ultimately, this results in a higher overall cost for the TMR solution. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a bus current detection module based on shunt resistors, which solves the problems of low accuracy and high cost in high current detection.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a bus current detection module based on a shunt resistor, comprising a bus substrate, a copper plane formed by CGDS technology, a shunt resistor, and a PCB board; the bus substrate has a slot, and the copper plane includes at least copper terminals formed at both ends of the bus substrate along its length and a second copper plane formed at the upper end of the slot; the shunt resistor is disposed on the second copper plane; a signal processing chip is mounted on the PCB board, and the PCB board is electrically connected to the shunt resistor to obtain the potential difference signal across the shunt resistor.

[0007] The above solution effectively overcomes the resistance fluctuations caused by temperature rise in traditional aluminum materials by using a low temperature coefficient manganese-copper-tin alloy as the shunt resistor material. Combined with the stable equivalent resistance characteristics of the aluminum substrate, it achieves a high-precision detection of 0.1% under high current conditions, significantly improving detection accuracy. In terms of cost control, CGDS technology is used to form a copper plane to solve the contact resistance problem, which greatly reduces manufacturing costs while ensuring performance.

[0008] Preferably, the busbar substrate is made of aluminum.

[0009] Preferably, the shunt resistor is a manganese-copper-tin alloy shunt.

[0010] Preferably, the signal processing chip includes an operational amplifier, which forms a subsequent test loop. The subsequent test loop is electrically connected to the shunt resistor on the PCB board to transmit the potential difference signal across the shunt resistor.

[0011] Preferably, the copper terminal is used to connect to an external copper conductive terminal.

[0012] Preferably, the second copper plane serves as the welding carrier for the shunt resistor, and the shunt resistor is welded and fixed to the second copper plane.

[0013] Preferably, the groove is formed along the thickness direction of the busbar substrate and extends through the width direction of the busbar substrate.

[0014] Preferably, the PCB board is electrically connected to the two terminals of the shunt resistor via wires or soldered pins.

[0015] Preferably, the copper plane is formed by accelerating nanoscale metal particles and then directing them onto the surface of the busbar substrate.

[0016] Preferably, the vertical projection of the current detection point of the shunt resistor on the busbar substrate is located within the extension range of the slot, so that the current path of the busbar substrate passes through the shunt resistor.

[0017] This invention provides a bus current detection module based on a shunt resistor. It has the following advantages:

[0018] 1. This invention utilizes a manganese-copper-tin alloy as the shunt resistor material, leveraging its extremely low temperature coefficient to effectively reduce resistance fluctuations caused by temperature changes, thereby achieving high-precision current measurement in high-current detection scenarios. Using aluminum as the bus substrate material significantly reduces raw material costs compared to traditional copper. While aluminum has a slightly higher resistivity than copper, its temperature rise under high-current conditions is limited, maintaining stable resistance and meeting current detection requirements, further improving cost-effectiveness. The shunt resistor-based bus current detection module provided by this invention has a compact design and reasonable structure, facilitating integration and application in various power electronics, automotive electronics, and photovoltaic energy storage scenarios.

[0019] 2. This invention uses CGDS technology to accelerate nanoscale metal particles and then directionally apply them to the surface of the busbar substrate, forming a copper plane with high conductivity and strong tensile strength. This solves the material matching problem when connecting the aluminum substrate to external copper terminals and also significantly improves the bonding strength between the copper layer and the substrate.

[0020] 3. The present invention creates a slot structure on the bus substrate and guides the current to flow in a concentrated manner through the second copper plane area at the upper end of the slot, thereby ensuring a stable current ratio flowing through the shunt resistor. Attached Figure Description

[0021] Figure 1 This is a perspective view of the present invention;

[0022] Figure 2 This is a front view of the present invention;

[0023] Figure 3 This is a side view of the present invention.

[0024] The components include: 1. Busbar substrate; 2. PCB board; 3. Shunt resistor; 4. Post-stage test loop; and 5. Copper terminals. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please see the appendix Figure 1 -Appendix Figure 3 This invention provides a bus current detection module based on a shunt resistor, including a bus substrate 1, a copper plane formed by CGDS technology, a shunt resistor 3, and a PCB board 2. The bus substrate 1 has a slot, and the copper plane includes at least copper terminals 5 formed at both ends of the length direction of the bus substrate 1 and a second copper plane formed at the upper end of the slot. The shunt resistor 3 is disposed on the second copper plane. The PCB board 2 is equipped with a signal processing chip, and the PCB board 2 is electrically connected to the shunt resistor 3 to obtain the potential difference signal across the shunt resistor 3.

[0027] Specifically, in one embodiment, the bus substrate 1 is an aluminum plate with dimensions of 200mm × 40mm × 10mm, and a groove structure with a width of 5.6mm, a depth of 1mm, and a width spanning 40mm is formed along the thickness direction to guide the current to flow concentrated through the second copper plane area at the upper end of the groove, thereby ensuring a stable current ratio flowing through the shunt resistor 3 and avoiding shunt interference. This copper plane is formed by directional deposition of nano-copper particles at three times the speed of sound using CGDS technology, possessing both high conductivity and strong tensile strength. This solves the material matching problem between the aluminum substrate and the external copper terminal (dimensions of 30mm × 40mm × 0.2mm), and also provides a stable welding carrier for the shunt resistor 3. The resistor is a 5930 packaged manganese-copper-tin alloy shunt with a resistance of 0.1mΩ. Its two ends are soldered to the two sides of a second copper plane with dimensions of 5.2mm×8.75mm×0.2mm. The PCB board equipped with an operational amplifier and a high-precision ADC is directly connected to the two ends of the resistor through wires or surface mount pins to obtain its weak potential difference signal in real time (such as about 497.51μV under a total current of 1000A), providing an accurate electrical signal basis for subsequent current calculations.

[0028] The busbar substrate 1 is made of aluminum.

[0029] Specifically, the busbar substrate 1 is made of industrial pure aluminum with a resistivity of 0.0283 × 10⁻ 6 Ω・m, approximately 0.018×10⁻ 6 With a resistivity of 63.7% (Ω·m), aluminum, despite its slightly higher resistivity, exhibits extremely limited temperature rise under high current conditions (e.g., 1000A), maintaining stable resistance over long periods and avoiding additional detection errors caused by temperature fluctuations. Aluminum is only 1 / 3 to 1 / 4 the price of copper, significantly reducing raw material costs and making it suitable for mass production. In terms of performance, aluminum substrates not only possess stable electrical properties but also offer lightweight advantages, making them particularly suitable for weight-sensitive applications such as automotive electronics and photovoltaic energy storage.

[0030] The shunt resistor 3 is a manganese copper-tin alloy shunt.

[0031] Specifically, the Shunt resistor 3 is made of manganese-copper-tin alloy and is packaged in a 5930 surface mount package (size 5.2mm × 8.75mm × 0.2mm). Its standard resistance is 0.1mΩ, and its temperature coefficient (TCR) is controlled within the range of 0~±10PPM / K, which is much lower than that of aluminum (3900PPM / K). This low TCR characteristic ensures that the resistance value is almost stable when the temperature changes due to high current heating, thereby avoiding detection errors. It is a core component for achieving accurate high current detection. At the same time, the 0.1mΩ resistance value can generate a weak potential difference that can be captured by the ADC under high current (e.g., about 497.51μV at 1000A), balancing detection accuracy and safety. In addition, this model has achieved mature mass production and has high supply stability.

[0032] The signal processing chip includes an operational amplifier, which forms the subsequent test loop 4. The subsequent test loop 4 is electrically connected to the shunt resistor 3 on the PCB board 2 to transmit the potential difference signal across the shunt resistor 3.

[0033] Specifically, the signal processing chip uses a high-gain operational amplifier as its core, which, together with the wires and solder joints on PCB board 2, forms the subsequent test loop 4. The input of this loop is directly soldered to both ends of the shunt resistor 3, and the output is connected to a high-precision ADC, achieving a signal capture accuracy of 0.1%. Under high current conditions, the potential difference signal generated by the shunt resistor is extremely weak (e.g., only 497.51μV at 1000A current). The operational amplifier linearly amplifies this signal, effectively preventing distortion or interference during transmission, thus forming a closed-loop signal transmission path of "shunt resistor → operational amplifier → ADC". This ensures that the potential difference signal is stably and losslessly transmitted to the ADC, ultimately achieving a current detection accuracy of 0.1%, meeting the high-precision measurement requirements of high-current applications.

[0034] Copper terminal 5 is used to connect to an external copper conductive terminal.

[0035] Specifically, copper terminals 5 are extended at both ends of the bus substrate 1 along its length using CGDS technology, with dimensions of 30mm × 40mm × 0.2mm. Their material is consistent with that of the external copper conductive terminals, thus avoiding the problem of excessive contact resistance caused by direct connection between the aluminum substrate and the copper terminals, effectively reducing current transmission loss and meeting the transmission requirements of high currents such as 1000A. At the same time, the copper layer formed by CGDS technology has high bonding strength with the aluminum substrate and has better tensile strength than traditional electroplated copper layers. It can ensure that the copper terminals do not fall off or deform under harsh working conditions such as vibration and impact (such as during vehicle operation), ensuring the long-term structural stability of the module and external circuit connection, and is suitable for harsh industrial or automotive environments.

[0036] The second copper plane serves as the welding carrier for the shunt resistor 3, which is then welded and fixed to the second copper plane.

[0037] Specifically, the second copper plane is formed on the upper end of the slot of the bus substrate 1 using CGDS technology. Its dimensions are designed to be 5.2mm × 8.75mm × 0.2mm, with a surface flatness error controlled within ≤0.05mm. This ensures a perfect size match with the shunt resistor 3, which has a 5930 package size of approximately 5.9mm × 3.0mm. Reliable soldering is achieved using lead-free solder, ensuring full contact between the resistor and the copper plane, with a contact resistance at the solder joint not exceeding 5mΩ. This plane not only serves as a soldering carrier, but the high conductivity of its copper material also ensures that the current from the bus substrate flows efficiently and evenly through the shunt resistor, effectively avoiding localized overheating caused by excessive contact resistance. Simultaneously, the robust soldering structure prevents the resistor from detaching under high current conditions, thus guaranteeing the continuity of the detection path and the stability of current conduction.

[0038] The groove is opened along the thickness direction of the busbar substrate and extends through the width direction of the busbar substrate.

[0039] Specifically, a U-shaped current channel with a depth of 1 mm and a width of 5.6 mm is opened on the busbar substrate 1 (thickness 10 mm) along the thickness direction and completely penetrates along the width direction of the substrate (40 mm). This structure restricts the current path to flow from one side of the slot through the shunt resistor (3) on the second copper plane and then to the other side of the slot, thereby effectively preventing the current from bypassing and ensuring that the total current flows through the sampling resistor. By combining the equivalent resistance of the current path of the aluminum substrate with the resistance of the shunt resistor 3, the ratio of the total current to the current flowing through the shunt resistor can be stably controlled, providing a reliable proportional basis for the accurate measurement of the total current.

[0040] PCB board 2 is electrically connected to the two terminals of shunt resistor 3 via wires or soldered pins.

[0041] Specifically, the electrical connection between PCB board 2 and Shunt resistor 3 can be achieved in two ways: First, tinned copper wire is used, with one end soldered to the Shunt resistor electrode and the other end connected to the signal input pin on the PCB board. Second, surface mount soldering is used, allowing the Shunt resistor electrode to be directly soldered to the corresponding pad on the PCB board via SMT (Surface Mount Technology), with the solder point spacing matching the resistor electrode spacing. Both methods achieve low-loss signal transmission with a contact resistance of no more than 5mΩ, effectively reducing potential difference signal loss during transmission and avoiding additional errors introduced by connection impedance. Wire connection is suitable for situations where there is a mounting gap between the PCB and the resistor (such as when the module contains other components), while surface mount soldering is more suitable for compact layouts (such as miniaturized automotive electronic modules). Both methods ensure stable and accurate signal transmission.

[0042] The copper plane is formed by accelerating nanoscale metal particles and then directing them onto the surface of the busbar substrate 1.

[0043] Specifically, the copper plane is formed by accelerating 50-100nm copper nanoparticles to approximately 1020m / s (3 times the speed of sound) and then directionally ejecting them into a designated area (both ends and the top of the groove) of an aluminum busbar substrate 1. During this process, the high-speed particles penetrate deep into the micro-slits on the aluminum substrate surface, generating a strong "anchoring" effect. This results in an extremely high bonding strength between the formed 0.2mm thick dense copper layer and the substrate, with a tensile strength ≥200MPa, far exceeding that of traditional electroplated copper layers. This effectively prevents detachment under vibration and thermal cycling, ensuring the long-term reliability of the module. Simultaneously, the copper layer is dense and defect-free, with a resistivity of approximately 0.0185×10⁻⁻⁻⁶. 6 Its Ω·m (approximately the same as that of pure copper) ensures excellent high conductivity and avoids excessive contact resistance caused by bubbles or impurities, thus making it perfectly suited for high current transmission scenarios.

[0044] The vertical projection of the current detection point of the shunt resistor 3 on the busbar substrate 1 is located within the extension range of the slot, so that the current path of the busbar substrate 1 passes through the shunt resistor 3.

[0045] Specifically, in the current detection structure, the vertical projection of the current detection point of the shunt resistor 3 (i.e., the midpoint of the line connecting its two electrode centers) onto the busbar substrate 1 is strictly within the extension range of the slot (slot width 5.6mm, projection point deviating from the center of the slot by no more than 0.2mm). This ensures that all the current on the busbar substrate 1 flows through the aluminum substrate below the projection area and sequentially through the complete path of "aluminum substrate → copper plane → shunt resistor → copper plane → aluminum substrate". This effectively avoids the current shunting error caused by some current bypassing the shunt resistor due to the detection point deviating from the slot, thus ensuring that the proportion of current flowing through the shunt resistor remains constant. Combining the equivalent resistance of the aluminum plate (0.5uΩ) and the resistance of the shunt resistor (100uΩ), the total current can be accurately calculated (e.g., a total current of 1000A corresponds to a detection current of approximately 4.9751A), maintaining stable detection accuracy over a long period.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A bus current detection module based on a shunt resistor, characterized in that, The device includes a bus substrate (1), a copper plane formed by CGDS technology, a shunt resistor (3), and a PCB board (2); the bus substrate (1) is provided with a groove, and the copper plane includes at least copper terminals (5) formed at both ends of the bus substrate (1) along its length and a second copper plane formed at the upper end of the groove; the shunt resistor (3) is disposed on the second copper plane; the PCB board (2) is equipped with a signal processing chip, and the PCB board (2) is electrically connected to the shunt resistor (3) to obtain the potential difference signal across the shunt resistor (3).

2. The bus current detection module based on a shunt resistor according to claim 1, characterized in that, The busbar substrate (1) is made of aluminum.

3. The bus current detection module based on a shunt resistor according to claim 1, characterized in that, The shunt resistor (3) is a manganese copper-tin alloy shunt.

4. The bus current detection module based on a shunt resistor according to claim 1, characterized in that, The signal processing chip includes an operational amplifier, which forms a post-stage test loop (4). The post-stage test loop (4) is electrically connected to the shunt resistor (3) on the PCB board (2) to transmit the potential difference signal across the shunt resistor (3).

5. A bus current detection module based on a shunt resistor according to claim 1, characterized in that, The copper terminal (5) is used to connect to an external copper conductive terminal.

6. The bus current detection module based on a shunt resistor according to claim 1, characterized in that, The second copper plane serves as the welding carrier for the shunt resistor (3), and the shunt resistor (3) is welded and fixed to the second copper plane.

7. A bus current detection module based on a shunt resistor according to claim 1, characterized in that, The groove is formed along the thickness direction of the busbar substrate and extends through the width direction of the busbar substrate.

8. A bus current detection module based on a shunt resistor according to claim 1, characterized in that, The PCB board (2) is electrically connected to the two terminals of the shunt resistor (3) via wires or soldered pins.

9. A bus current detection module based on a shunt resistor according to claim 1, characterized in that, The copper plane is formed by accelerating nanoscale metal particles and then directing them onto the surface of the busbar substrate (1).

10. A bus current detection module based on a shunt resistor according to claim 1, characterized in that, The vertical projection of the current detection point of the shunt resistor (3) on the busbar substrate (1) is located within the extension range of the slot, so that the current path of the busbar substrate (1) passes through the shunt resistor (3).

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