Plate type shunt special for large-current charging and discharging of new energy vehicle

Abstract

The utility model provides a special plate-type shunt for large-current charging and discharging of a new energy vehicle, which comprises a PCB (Printed Circuit Board) and a plate-shaped resistor, the plate-shaped resistor comprises a manganese-copper plate body and red copper plate bodies on two sides, and the manganese-copper plate body is respectively welded and fixed with the red copper plate bodies on two sides; equipotential difference notches are respectively formed in red copper plate bodies on two sides of the plate-shaped resistor, and any positions of the inner wall and the edge of each equipotential difference notch are equipotential; the PCB is placed on the upper side of the plate-shaped resistor and fixedly connected with the plate-shaped resistor through vacuum reflow soldering, the PCB is provided with two sampling wiring terminals corresponding to the red copper plate bodies, and the sampling wiring terminals make contact with the inner walls and the edges of the equal-potential-difference notches of the red copper plate bodies. Due to the fact that any position of the inner wall and the edge of each equal-potential-difference notch is equal in potential, a sampling wiring terminal of the PCB only needs to be in contact with any position of the inner wall and the edge of each equal-potential-difference notch, and it is guaranteed that the temperature and resistance value change corresponding report of a current device of the plate-shaped resistor is kept consistent with that of a current product.

Description

Technical Field

[0001] The utility model relates to the field of new energy vehicles, in particular to a plate-type shunt for high-current charging and discharging used in new energy vehicles or charging piles. Background Art

[0002] The shunt is made based on the principle that voltage is generated across a resistor when DC current passes through it. It can pass a large current through a precise resistor. When DC current passes through it, a voltage drop is generated for display on the DC ammeter. However, when the shunt contacts the electrical connection line, the resistance of the shunt's terminal itself is too large, resulting in an inaccurate value for the tested DC current.

[0003] Shunts are generally divided into plug-in shunts, chip shunts, U-shaped shunts, plate shunts, etc. In view of the fact that the charging and discharging current of new energy vehicles can reach 500 to 600A, and its instantaneous maximum current may reach 1000A, plate shunts are generally used in the field of new energy vehicles. Points are set on the plate resistors on the plate shunts, and the sampling terminals of the plate shunts are connected to the points, so as to sample the circuit flowing through the shunt in real time.

[0004] Due to the large temperature difference in the operating environment of new energy vehicles (-40°~120°), shunt manufacturers need to measure the resistance of each shunt at the corresponding temperature point. The temperature and resistance change curve of each shunt is unique. If the shunt needs to be replaced, it cannot be guaranteed that the replacement shunt will have the same change curve as the previous shunt. If not, the parameters need to be recalibrated, which is time-consuming and labor-intensive.

[0005] The existing plate-shaped flow divider has the following disadvantages:

[0006] (1) At present, the general practice is to conduct random inspections on the same batch of plate resistors when producing shunt plate resistors, and generate corresponding reports on the temperature and resistance changes of the shunt plate resistors in the current batch. However, due to the influence of the dimensional tolerance and assembly error between the components, the value points of the assembled plate shunt cannot coincide with the value points during the test, resulting in the temperature and resistance change corresponding reports of the shunt plate resistors being inconsistent with the current products.

[0007] (2) The PCB board and the plate resistor of the existing plate-shaped shunt are generally connected by riveting and screws. However, the plate-shaped shunt used in new energy vehicles should have certain anti-vibration and anti-collision properties. The screws or rivets themselves have torque and will break after a long time. In addition, the riveted or screwed connection has its own stress, which may easily cause the PCB sampling terminal to fall off after long-term use.

[0008] The utility model with application number CN201822182417.0 discloses a shunt, including two coplanar connection plates (1), characterized in that: a resistor plate (2) is connected between the two connection plates (1), at least one second through hole (4) is provided on each connection plate (1), and at least one first through hole (3) or a connecting column (12) is provided on each connection plate (1). Advantages of the utility model: The connection plates and resistor plates of this scheme are welded by vacuum electron welding, and at the same time, the brass used in the connection plates in the prior art is replaced with red copper, which improves the stability of the resistance value. The resistance adjustment groove is added on the resistor plate to facilitate the resistance adjustment of the shunt, and the resistance adjustment is simple. At the same time, two first flat pads are provided at the first through hole, or a connecting column is provided, which ensures the stability of the resistance value of the circuit connected after the shunt is used, and its processing technology is simple, less material is used, the quality is small, and the yield rate is high.

[0009] However, the diverter in the above patent technology cannot meet the needs of new energy vehicles and cannot solve the technical problems existing in the prior art. Utility Model Content

[0010] The purpose of the utility model is to provide a plate-type shunt dedicated to high current charging and discharging of new energy vehicles to solve the problems raised in the above background technology:

[0011] (1) How to ensure that the resistance values ​​between the sampled plate resistors during the production process are absolutely consistent with the resistance values ​​between the sampled plate resistors after assembly, and thus ensure that the corresponding reports on the temperature and resistance changes of the plate resistors are consistent with the current products.

[0012] (2) What means should be used to fix the PCB board and the plate resistor of the plate shunt to meet the requirements of anti-vibration and anti-collision performance of new energy vehicles during use?

[0013] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0014] A special plate-type shunt for high-current charging and discharging of new energy vehicles, comprising a PCB circuit board and a plate-shaped resistor, wherein the plate-shaped resistor comprises a manganese copper plate body and red copper plates on both sides, and the manganese copper plate body is respectively welded and fixed to the red copper plates on both sides;

[0015] The copper plates on both sides of the plate-shaped resistor are respectively provided with equal potential difference notches, and the inner wall and any position of the edge of each equal potential difference notch are of equal potential;

[0016] The PCB circuit board is placed on the upper side of the plate-shaped resistor and is fixedly connected to the plate-shaped resistor through vacuum reflow soldering. The PCB circuit board is respectively provided with two sampling terminals corresponding to the copper plate body, and the sampling terminals are in contact with the inner wall and edge position of the equipotential difference notch of the copper plate body.

[0017] Since the impedance of the manganese copper plate is relatively large, and the impedance of the copper plate is relatively small, but the temperature of the copper plate is relatively high, the equipotential difference notch is equivalent to changing the original linear equipotential potential into a planar equipotential potential formed by the inner wall and edge of the equipotential difference notch which is easier to locate and connect. Accurate sampling can be achieved by simply connecting the inner wall and edge of the equipotential difference notch.

[0018] Since the inner wall and any position of the edge of each equipotential difference slot are of the same potential, as long as the sampling terminal of the PCB circuit board is in contact with the inner wall and any position of the edge of the equipotential difference slot, it can ensure that the resistance values ​​between the sampling points of the plate resistor measured during the production process are absolutely consistent with the resistance values ​​between the sampling points of the plate resistor after assembly (the resistance values ​​of the sampling points are consistent before and after the welding operation), thereby ensuring that the temperature and resistance change reports of the flow meter of the plate resistor are consistent with the current product.

[0019] In addition, the sampling terminals of the PCB circuit board are welded to the copper plate body. The positioning of the equipotential difference notches can not only reduce the probability of empty welding, but also ensure the stability of the resistance between the plate resistor value points as long as there is contact between the sampling terminals and the copper plate body, even if there are bubbles during welding, and minimize the influence of bubbles during welding.

[0020] Moreover, the welding method can avoid the problem of riveting and bolting with breakage and detachment from the PCB sampling terminal, so that the special plate-type shunt for high-current charging and discharging of new energy vehicles can meet the requirements of new energy vehicles for anti-vibration and anti-collision performance during use.

[0021] When the ambient temperature of the plate resistor changes, the parameters of the plate resistor will also change. This change usually leads to instability of the static operating point, thereby deteriorating the dynamic performance of the circuit. After adopting such a structure, the contact area between the sampling terminal and the copper plate is reduced, and the temperature change curve of the plate resistor also tends to be gentle.

[0022] The temperature coefficient of this special plate-type shunt for high-current charging and discharging of new energy vehicles can be maintained between 10 and 20, which is ahead of the temperature coefficient of 100 to 200 of shunts in the industry.

[0023] On the basis of the above technical solution, the present invention can also be improved as follows.

[0024] Furthermore, the cross-sectional shape of the equipotential difference notch on the copper plate is a "concave"-shaped structure, and the area where the copper plate extends into the equipotential difference notch forms a contact protrusion that is convenient for matching with the sampling terminal of the PCB circuit board. After adopting such a structure, the "concave"-shaped equipotential difference notch further increases the area of ​​the equipotential position, and the contact protrusion is more convenient for welding with the sampling terminal.

[0025] Furthermore, the PCB circuit board is provided with a thermistor for monitoring its own heating temperature. With such a structure, the thermistor can detect the heating temperature of the plate-type shunt dedicated for high current charging and discharging of the new energy vehicle.

[0026] Furthermore, the ratio of the projection area of ​​the PCB circuit board on the surface of the plate-shaped resistor to the plate-shaped resistor is 1:(3-4). Compared with the existing shunt, the structure can not only completely cover the manganese copper plate, but also reduce the number of electronic components on the PCB circuit board, reduce the heating area, and the heat will not be transferred to other components. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a top view of an embodiment of a plate-type shunt specially used for high-current charging and discharging of new energy vehicles.

[0028] Figure 2 It is a bottom view of an embodiment of the plate-type shunt specially used for high-current charging and discharging of new energy vehicles.

[0029] Figure 3 It is a circuit schematic diagram of an embodiment of a plate-type shunt dedicated for high-current charging and discharging of new energy vehicles.

[0030] Figure 4 It is a linear graph of the test results of the embodiment of the plate-type shunt dedicated for high-current charging and discharging of new energy vehicles.

[0031] Figure 5 It is a linear graph of the test results of the plate-type diverter in the prior art.

[0032] Description of the numbers in the figure:

[0033] Plate resistor-100; manganese copper plate body-110; copper plate body-120; equipotential difference notch-121; contact protrusion-122; PCB circuit board-200; sampling terminal blocks-P1, P2; thermistors-Rt1, Rt2. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation of the utility model is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific implementation disclosed below.

[0035] The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementations.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] See also Figures 1 to 3 .

[0038] The special plate-type shunt for high-current charging and discharging of new energy vehicles includes a PCB circuit board 200 and a plate-shaped resistor 100.

[0039] The plate resistor 100 includes a manganese copper plate body 110 and copper plates 120 on both sides. The manganese copper plate body 110 is welded and fixed to the copper plates 120 on both sides. The copper plates 120 on both sides of the plate resistor 100 are respectively provided with equipotential difference slots 121 running through the upper and lower end surfaces thereof. The inner wall and any position of the edge of each equipotential difference slot 121 are of equipotential. The cross-sectional shape of the equipotential difference slots 121 on the copper plate body 120 is generally a "concave"-shaped structure. The area where the copper plate body 120 extends into the equipotential difference slots 121 forms a contact protrusion 122 that is convenient for cooperating with the sampling terminals P1 and P2 of the PCB circuit board 200.

[0040] The PCB circuit board 200 is placed on the upper side of the plate resistor 100 and is fixedly connected to the plate resistor 100 through vacuum reflow soldering. The PCB circuit board 200 is respectively provided with two sampling terminals P1 and P2 corresponding to the copper plate body 120. The sampling terminals P1 and P2 are in contact with the inner wall and edge position of the equipotential difference notch 121 of the copper plate body 120. The PCB circuit board 200 is provided with two thermistors (NTC) Rt1 and Rt2 for monitoring its own heating temperature. The ratio of the projection area of ​​the PCB circuit board 200 on the surface of the plate resistor 100 to the plate resistor 100 is 1:4.

[0041] Comparative experiment

[0042] The shunt used in the existing new energy field and the special plate-type shunt for high-current charging and discharging of new energy vehicles were selected to conduct temperature drift detection experiments, and the experimental conditions of the two were the same.

[0043] Test conditions: (1) Place the product to be tested in a high and low temperature chamber and adjust the temperature from -40°C to 120°C in intervals of 10°C; (2) Record the values ​​and calculate the TCR value based on 20°C.

[0044] Equipment: High and Low Temperature Chamber, Manufacturer: Espec, Model: MC-810P.

[0045] Test data record, the test results of the special plate shunt for high current charging and discharging of new energy vehicles in this embodiment are as follows:

[0046] Serial number Experimental temperature (℃) Measured resistance (mΩ) TCR ppm Accuracy (%) 1 -40 0.024953 -29.9569 -0.1877 2 -30 0.024965 -26.362 -0.1398 3 -20 0.024977 -20.9698 -0.0919 4 -10 0.024985 -17.3084 -0.0599 5 0 0.024992 -11.9827 -0.032 6 10 0.024996 -7.9885 -0.016 7 20 0.024998 0 -0.008 8 30 0.025001 11.9827 0.004 9 40 0.025006 15.977 0.024 10 50 0.025012 18.6398 0.0479 11 60 0.025017 18.9727 0.0679 12 70 0.025024 20.7701 0.0958 13 80 0.02503 21.3027 0.1198 14 90 0.025034 20.5418 0.1358 15 100 0.025037 19.472 0.1478 16 110 0.025044 20.415 0.1757 17 120 0.02505 20.7701 0.1997

[0047] like Figure 4 As shown, shunt TCR test: -40℃-120℃≤30ppm.

[0048] Test data records, the test results of the existing plate-type shunt (this time we selected the industry's leading foreign-made and commercially available plate-type shunt products for comparative experiments) are as follows:

[0049]

[0050]

[0051] like Figure 5 As shown, shunt TCR test: -40℃-80℃≤30ppm.

[0052] The above is only one embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the principle of the present invention, and these should also be regarded as belonging to the protection scope of the present invention.

Claims

1. A special plate-type shunt for high-current charging and discharging of new energy vehicles, comprising a PCB circuit board (200) and a plate-shaped resistor (100), wherein the plate-shaped resistor (100) comprises a manganese copper plate body (110) and red copper plates (120) on both sides, and the manganese copper plate body (110) is respectively welded and fixed to the red copper plates (120) on both sides; Its characteristics are: Equipotential difference notches (121) are respectively formed on the copper plates (120) on both sides of the plate-shaped resistor (100), and any position on the inner wall and edge of each equipotential difference notch (121) is of equal potential; The PCB circuit board (200) is placed on the upper side of the plate-shaped resistor (100) and is fixedly connected to the plate-shaped resistor (100) by vacuum reflow soldering; the PCB circuit board (200) is respectively provided with two sampling connection terminals (P1, P2) corresponding to the copper plate body (120); the sampling connection terminals (P1, P2) are in contact with the inner wall or edge position of the equipotential difference notch (121) of the copper plate body (120).

2. The plate-type shunt dedicated for high current charging and discharging of new energy vehicles according to claim 1 is characterized in that: The cross-sectional shape of the equipotential difference notch (121) on the copper plate (120) is a "concave"-shaped structure, and the area of ​​the copper plate (120) extending into the equipotential difference notch (121) forms a contact protrusion (122) that is convenient for mating with the sampling connection terminals (P1, P2) of the PCB circuit board (200).

3. The plate-type shunt dedicated for high current charging and discharging of new energy vehicles according to claim 1 is characterized in that: The PCB circuit board (200) is provided with thermistors (Rt1, Rt2) for monitoring its own heating temperature.

4. The plate-type shunt dedicated for high current charging and discharging of new energy vehicles according to claim 3 is characterized in that: The ratio of the projected area of ​​the PCB circuit board (200) on the surface of the plate-shaped resistor (100) to the plate-shaped resistor (100) is 1:(3-4).

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