Resistor, distribution box, vehicle and current measuring method

Abstract

The invention discloses a resistor, a distribution box, a vehicle and a current measuring method, and the resistor comprises a shunting part; the copper bar comprises at least one first electric measuring point and at least one groove, the shunting part is arranged on the copper bar in series, each groove is formed in each first electric measuring point, the grooves do not penetrate through the copper bar and are used for being connected with the voltage measuring pins, and the voltage measuring pins are used for measuring the total voltage of the shunting part and the copper bar. According to the invention, the temperature drift change of the shunt is small, and the current detection precision is improved.

Description

Technical Field

[0001] This invention relates to the field of current detection, and particularly to a resistor, a distribution box, a vehicle, and a current measurement method. Background Technology

[0002] In the battery pack of an electric vehicle, the shunt resistor is a key sensor used for accurate current measurement. It is typically made of a piece of resistive alloy and connected in series in the main circuit of the battery.

[0003] Its working principle is based on Ohm's law (voltage = current × resistance). When current flows through a shunt resistor, a tiny voltage drop is generated across it. By measuring this voltage drop and dividing it by the known precise resistance value, the battery management system can calculate the real-time current. This current data is crucial for calculating the battery's state of charge, state of health, implementing overcurrent protection, and optimizing energy management.

[0004] However, due to the influence of the temperature coefficient of resistance (TCR), which represents the relative change in resistance when the temperature changes by 1 degree Celsius, the resistance of the resistive material changes with temperature. This leads to inaccurate current detection, as it is easily affected by ambient temperature. Therefore, existing technologies employ methods to reduce temperature drift errors. However, achieving high-precision temperature compensation requires additional temperature sensing circuitry, more complex calibration procedures, and more powerful processors to run the compensation algorithms, increasing system complexity and cost. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of inaccurate current detection in existing technologies. This invention provides a resistor that minimizes the temperature drift of the shunt, thereby improving the accuracy of current detection.

[0006] To address the aforementioned technical problems, embodiments of the present invention disclose a resistor, comprising:

[0007] Branching section;

[0008] A copper busbar includes at least one first electrical measurement point and at least one groove. The shunt is connected in series with the copper busbar. Each groove is located at each first electrical measurement point and does not penetrate the copper busbar. The groove is used to connect to a voltage measurement pin, which is used to measure the total voltage of the shunt and the copper busbar.

[0009] By adopting the above technical solution, a non-penetrating groove is set at the first electrical measurement point of the copper busbar, so that the voltage measurement pin can be connected in the groove. In this way, when measuring the total voltage including the shunt section and part of the copper busbar voltage drop, the temperature coefficient of the copper busbar is effectively introduced to couple with the temperature coefficient of the shunt section (such as alloy), realizing the active control of the temperature coefficient of the resistance of the measurement path, and providing a physical basis for reducing the overall temperature drift.

[0010] Specifically, most of the current flowing through the copper busbar bypasses the groove and flows directly to the shunt, or from the shunt to other components via the copper busbar. The remaining portion flows directly into the groove, which does not penetrate the copper busbar. The current flowing into the groove is then divided into two parts: one flows directly to the shunt section, and the other surges to the voltage measurement pins. Thus, by using a non-penetrating groove, the current flowing through the copper busbar between the voltage measurement pins is reduced, thereby stabilizing the overall resistance of the resistor and reducing the adverse effects of temperature drift in the shunt section on the overall current sensing.

[0011] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a resistor, wherein the groove includes a bottom wall formed by the copper busbar, and the voltage measurement pin is connected to the bottom wall.

[0012] By employing the above technical solution, it is clearly defined that the bottom wall of the groove is formed by the copper busbar itself and connected to it, ensuring that the current must flow from the bottom of the groove through the pins. This structure forcibly alters the local current density distribution, constraining and extending the current path through the measurement point, thereby effectively reducing the current flowing through the copper busbar between the voltage measurement pins.

[0013] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a resistor including a first current path and a second current path, wherein the first current path is formed by the bottom wall and the voltage measurement pin, and the second current path is formed by the copper busbar and the current shunt, wherein the current flowing through the first current path is less than the current flowing through the second current path.

[0014] By employing the above technical solution, the current in the first current path (e.g., through the bottom wall and pins) is explicitly limited to be less than that in the second current path (e.g., through the main copper busbar and the shunt). This directly quantifies and confirms the design effect of the groove structure, which successfully guides most of the measured current to the shunt for accurate sensing, while allowing only a small portion of the current to flow through the measurement point. This minimizes the adverse effects of the copper busbar's resistance and its large positive temperature coefficient on the overall measurement accuracy, achieving optimized allocation of the current path.

[0015] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a resistor in which the groove and the shunt portion have a first distance.

[0016] By adopting the above technical solution, by limiting the first distance between the groove and the shunt section, the design freedom to adjust the current path and coupling effect is provided, enabling technicians to finely design and optimize the temperature coefficient of the shunt for different application requirements or material properties.

[0017] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a resistor, wherein the copper busbar includes a first part and a second part, the current shunt is connected in series between the first part and the second part, the first electrical measurement point includes a first point and a second point, and the groove includes a first groove and a second groove;

[0018] The first groove is located at the first point, and the second groove is located at the second point. Both the first groove and the second groove are separated from the diversion section by the first distance.

[0019] By employing the above technical solution, a balanced and symmetrical measurement structure is achieved by symmetrically arranging the first and second slots on both sides of the current shunt section and maintaining a first distance from the current shunt section. This design ensures that the electrical environment of the two voltage measurement points is consistent, avoiding measurement errors introduced by the asymmetry of the unilateral structure. At the same time, dual-point measurement can more stably and reliably obtain the total voltage including the voltage drop of the copper busbars on both sides, improving the symmetry and overall stability of the current measurement.

[0020] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a resistor, wherein the shunt section includes an alloy resistor block having a negative temperature coefficient and the copper busbar having a positive temperature coefficient.

[0021] By adopting the above technical solution, the current shunt is defined as an alloy resistor block with a negative temperature coefficient, while the copper busbar has a positive temperature coefficient. The negative temperature coefficient of the alloy and the positive temperature coefficient of the copper busbar are coupled and canceled out by a specific structure (such as setting a groove), so that the overall resistance value is more stable at different temperatures by working synergistically at the material and structural levels.

[0022] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a resistor in which the shape of the groove includes a circle, an ellipse or a rhombus.

[0023] Embodiments of the present invention also disclose a power distribution box, which includes at least the resistor described in any of the above embodiments.

[0024] An embodiment of the present invention also discloses a vehicle, comprising:

[0025] The power distribution box in any of the above embodiments;

[0026] A battery pack, wherein the power distribution box is disposed within the battery pack;

[0027] The control unit includes a voltage measurement pin, which is connected to a recess in the resistor.

[0028] The present invention also discloses a current measurement method, using the vehicle in any of the above embodiments, comprising:

[0029] Connect the resistor in series to the current circuit to be measured;

[0030] The total voltage of the shunt and the copper busbar is obtained through the voltage measurement pin;

[0031] The loop current is calculated based on the total voltage and the nominal resistance value of the shunt section.

[0032] The current measurement method provided by adopting the above technical solution is based on the calculation of the total voltage including the voltage drop across the copper busbar. This method makes full use of the technical effect brought by the aforementioned resistor structure, that is, by measuring the voltage including the voltage drop of the controlled copper busbar, the calculated current value naturally includes the temperature compensation effect, thereby simplifying or reducing the dependence on the back-end software compensation algorithm and improving the response speed and overall robustness of the measurement system. Attached Figure Description

[0033] Figure 1 A schematic diagram of a resistor provided in an embodiment of this application is shown.

[0034] Figure 2 A schematic diagram of a resistor comprising two grooves is shown in an embodiment of this application.

[0035] Figure 3 A schematic diagram showing the connection between the groove of the resistor provided in an embodiment of this application and the voltage measurement pin is shown.

[0036] Figure 4 A schematic diagram showing the distribution of multiple measurement points of the resistor provided in the embodiments of this application is shown.

[0037] Figure 5 A schematic diagram of the first current path and the superimposed current path of the resistor provided in the embodiments of this application is shown.

[0038] Figure 6 A flowchart of the current measurement method provided in an embodiment of this application is shown. Detailed Implementation

[0039] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0040] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0041] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0042] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0043] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0044] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0045] This application provides a vehicle including a power distribution box, a battery pack, and a control unit. The power distribution box is located within the battery pack, and the control unit is capable of detecting and calculating the current flowing through the power distribution box within the battery pack. This current data is crucial for calculating the battery's state of charge and health, implementing overcurrent protection, and optimizing energy management.

[0046] For example, see Figure 1 The distribution box includes a resistor, which consists of a shunt 100 and a copper busbar 200. Current from the battery pack enters the distribution box through the copper busbar 200, and the shunt 100 is soldered to the copper busbar 200. Exemplarily, the copper busbar 200 has a total current recombination (TCR) of 3900 ppm / ℃. The copper busbar 200 can be made of pure copper, while the TCR of the shunt 100 is typically much smaller than that of the copper busbar 200, for example, only 150 ppm / ℃. This application does not limit the scope of the embodiment.

[0047] In some embodiments, see Figure 1 , Figure 2 The copper busbar 200 includes at least one first electrical measurement point 210 and at least one groove 220. The current shunt 100 is connected in series with the copper busbar 200. Each groove 220 is located at each first electrical measurement point 210, and the groove 220 does not penetrate the copper busbar 200. For example, there is a first distance d1 between the groove 220 and the current shunt 100.

[0048] For example, the control unit includes a voltage measurement pin 300, which is connected to the recess 220 of the resistor and is used to measure the total voltage of the shunt section 100 and the copper busbar 200.

[0049] By adopting the above technical solution, a non-penetrating groove 220 is set at the first electrical measurement point 210 of the copper busbar 200, so that the voltage measurement pin 300 can be connected in the groove 220. Thus, when measuring the total voltage including the voltage drop of the shunt section 100 and part of the copper busbar 200, the positive temperature coefficient of the copper busbar 200 is effectively introduced to couple with the temperature coefficient of the shunt section 100 (such as an alloy), thereby realizing the active control of the resistance temperature coefficient of the measurement path and providing a physical basis for reducing the overall temperature drift.

[0050] Specifically, most of the current flowing through the copper busbar 200 bypasses the recess 220 and flows directly to the shunt. The remaining portion flows directly into the recess 220, which does not penetrate the copper busbar 200. The current flowing into the recess 220 is then divided into two parts: one flows directly to the shunt section 100, and the other surges to the voltage measurement pin 300. Thus, by using the non-penetrating recess 220, the current flowing through the copper busbar 200 between the voltage measurement pins 300 is reduced, thereby stabilizing the overall resistance of the resistor and reducing the adverse effects of temperature drift in the shunt section 100 on the overall current detection.

[0051] In some embodiments, see Figure 1 , Figure 2 , Figure 3 The copper busbar 200 includes a first portion 230 and a second portion 240. A current shunt 100 is connected in series between the first portion 230 and the second portion 240. The first electrical measurement point 210 includes a first point 2101 and a second point 2102. The groove 220 includes a first groove 2201 and a second groove 2202. For example, see [reference needed]. Figure 1 , Figure 2 , Figure 3 The first groove 2201 is located at the first point 2101, and the second groove 2202 is located at the second point 2102. Both the first groove 2201 and the second groove 2202 are separated from the shunt section 100 by a first distance d1. By limiting the groove 220 to a first distance d1 between it and the shunt section 100, the design freedom to adjust the current path and coupling effect is provided, allowing technicians to finely design and optimize the temperature coefficient of the shunt for different application requirements or material properties.

[0052] Understandably, the embodiments of this application do not limit the first distance d1, for example, it can be 0.1mm, 0.5mm, 0.68mm, 1mm, 2mm, 5mm, etc. The embodiments of this application also do not limit the number of grooves 220 and the number of first electrical measurement points.

[0053] For example, temperature coefficient of resistance Where R1 represents the resistance value at the reference temperature, R2 represents the resistance value at the actual temperature, t1 represents the reference temperature (e.g., 25°C), and t2 represents the actual temperature. Therefore, as temperature changes, the temperature coefficient of resistance may be positive or negative. For example, the shunt 100 includes an alloy resistor block with a negative temperature coefficient, and the copper busbar 200 has a positive temperature coefficient. A positive temperature coefficient means that the resistance increases with increasing temperature, while a negative temperature coefficient means that the resistance decreases with increasing temperature. The negative temperature coefficient of the alloy and the positive temperature coefficient of the copper busbar 200 are coupled and canceled out by a specific structure (e.g., a groove 220).

[0054] In some embodiments, such as Figure 4 As shown, the shunt section 100 includes a second electrical measurement point 110 and a third electrical measurement point 120. Along the first direction X (the direction of current flow), the second electrical measurement point 110 is located near the first portion 230, and the third electrical measurement point 120 is located near the second portion 240. Exemplarily, the measurement pin of the control unit directly measures the first voltage value between the second electrical measurement point 110 and the third electrical measurement point 120. At that time, due to the large temperature drift of the shunt section 100, the error of the obtained current value is large at different temperatures, according to Ohm's law (current = voltage / resistance).

[0055] Based on this, the second voltage value can be obtained by measuring the voltage drop between the first electrical measurement point 210 and the second electrical measurement point 110 introduced in the embodiments of this application. Therefore, the voltage drop between the first electrical measurement point 210 and the third electrical measurement point 120 is The total resistance along the voltage measurement path between the first electrical measurement point and the third electrical measurement point 120 .

[0056] in, This indicates the current value flowing through the 200Ω copper busbar. This indicates the TCR of the 200 copper busbar. This indicates the TCR of the shunt section 100. This indicates the resistance value of the copper busbar 200 between the first electrical measurement point and the second electrical measurement point 110. This indicates the resistance value of the shunt section 100 between the second electrical measurement point 110 and the third electrical measurement point 120. This indicates the temperature during the measurement period. According to the formula above, the total resistance between the first and third electrical measurement points (120) is... Will be affected , Due to factors such as [various factors], Ohm's law (current = voltage / resistance) states that when the total resistance tends to stabilize, the measured current [will be higher / lower / lower]. This will make the measurement more accurate. The technical solution provided in this application embodiment, through an improved design of the copper busbar 200 structure, enables the surge of energy to the measurement pins to be more accurate. This reduces the total resistance between the first electrical measurement point and the third electrical measurement point 120, thereby decreasing the resistance between them. The impact.

[0057] In some embodiments, see Figure 2 , Figure 3 , Figure 4 The groove 220 includes a bottom wall 2203 and side walls (not shown in the figure). The bottom wall 2203 is formed by copper busbars 200. The voltage measurement pins 300 are connected to the bottom wall 2203. Due to the presence of the groove 220, current cannot flow directly through the groove 220, ensuring that the current must flow from the bottom of the groove 220 through the pins. This structure forcibly changes the local current density distribution, constraining and lengthening the current path through the measurement point, thereby effectively reducing the current flowing through the copper busbars 200 between the voltage measurement pins 300.

[0058] For example, see Figure 3 , Figure 4 , Figure 5 The resistor includes a first current path S1 and a second current path S2. The first current path S1 is formed by a bottom wall 2203 and a voltage measurement pin 300, and the second current path S2 is formed by a copper busbar 200 and a shunt section 100. The current flowing through the first current path S1 is less than the current flowing through the second current path S2. For example, due to the presence of the groove 220, most of the current bypasses the groove 220 and flows directly to the shunt section 100 through the second current path S2, or flows from the shunt section 100 to other components through the copper busbar 200. Only a small portion of the current flows through the first current path S1. Furthermore, since the groove 220 provided in this embodiment does not penetrate the copper busbar 200, the current flowing through the first current path S1 is further separated. Most of the current flows to the shunt section 100 through the bottom wall 2203, leaving only a smaller portion of the current flowing up to the voltage measurement pin 300, thereby reducing the current flowing up to the measurement pin. Keep it at a small value.

[0059] For example, suppose the total measured current is 100A. In a standard copper busbar 200 without the recess 220, the current between the measurement pins may be close to the total current, for example, up to tens of amperes, causing the resistance of the copper busbar 200 and its large positive temperature coefficient to significantly affect the total resistance of the measurement path. When a non-penetrating recess 220 is provided at the measurement point, the current path is forcibly changed. Most of the main current, for example, about 98A, will flow directly from the main body of the copper busbar 200 below the recess 220 (i.e., the second current path S2) through the shunt 100 (alloy resistance block). Since the recess 220 is non-penetrating, the current cannot flow through the sidewall of the recess 220, and only a small portion of the current, for example, about 2A, is forced to flow from the bottom wall 2203 of the recess 220 through the voltage measurement pin 300 (i.e., the first current path S1), forming the current flowing through the copper busbar 200 between the measurement points. Therefore, the current flowing through the copper busbar 200 between the measurement points... The value has decreased dramatically from what could have been a high value to a very low level.

[0060] According to the aforementioned theoretical formula, The significant reduction directly lowers the value in the formula. This factor has a weight in the overall resistance calculation. This means that, despite the temperature coefficient of the copper busbar material itself... The current distribution is significant, but its actual contribution to the overall measured resistance temperature drift is structurally weakened. This change in current distribution is key to achieving the effect of reducing the temperature coefficient.

[0061] In some embodiments, the shape of the groove 220 includes a circle, an ellipse, or a rhombus. It is understood that the embodiments of this application do not limit the shape of the groove 220; for example, it can also be rectangular. Furthermore, the embodiments of this application do not limit the position of the voltage measurement pin 300 on the bottom wall 2203.

[0062] In some embodiments, see Figure 6 and combined Figure 1 , Figure 2 , Figure 3 This application also provides a current measurement method, employing the resistor in any of the foregoing embodiments, comprising:

[0063] S100. Connect the resistor in series to the circuit of the current to be measured.

[0064] Specifically, the current-to-be-tested circuit consists of a battery pack and a distribution box. Resistors are connected in series between the battery pack and the distribution box. Current is transmitted through a copper busbar 200. The current flows from the battery pack through the copper busbar 200, the shunt section 100, and then back to the other components of the distribution box. During this process, the magnitude of the current flowing through the shunt section 100 is measured via the voltage measurement pin 300 of the control unit.

[0065] S200: Obtain the total voltage of the shunt section 100 and the copper busbar 200 through the voltage measurement pin 300;

[0066] For example, the voltage measurement pin 300 of the control unit is simultaneously connected to both the first electrical measurement point 120 and the third electrical measurement point 120 of the shunt section 100, enabling the acquisition of the total voltage of the shunt section 100 and the copper busbar 200. For example, the voltage measurement pin 300 of the control unit can also be simultaneously connected to both the first point 2101 and the second point 2102 of the first electrical measurement point, similarly enabling the acquisition of the total voltage value of the shunt section 100 and the copper busbar 200.

[0067] S300. The loop current is calculated based on the total voltage and the nominal resistance value of the shunt section 100.

[0068] For example, according to Ohm's law (current = voltage / resistance), the loop current value output by the battery pack can be obtained by dividing the measured total voltage value by the nominal resistance value of the shunt 100.

[0069] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A resistor, characterized in that, include: Branching section; A copper busbar includes at least one first electrical measurement point and at least one groove. The shunt is connected in series with the copper busbar. Each groove is located at each first electrical measurement point and does not penetrate the copper busbar. The groove is used to connect to a voltage measurement pin, which is used to measure the total voltage of the shunt and the copper busbar.

2. The resistor as claimed in claim 1, characterized in that, The groove includes a bottom wall formed by the copper busbar, and the voltage measurement pin is connected to the bottom wall.

3. The resistor as described in claim 2, characterized in that, It includes a first current path and a second current path. The first current path is formed by the bottom wall and the voltage measurement pin, and the second current path is formed by the copper busbar and the shunt section. The current flowing through the first current path is less than the current flowing through the second current path.

4. The resistor according to any one of claims 1-3, characterized in that, There is a first distance between the groove and the diversion section.

5. The resistor as claimed in claim 4, characterized in that, The copper busbar includes a first part and a second part, the current shunt is connected in series between the first part and the second part, the first electrical measurement point includes a first point and a second point, and the groove includes a first groove and a second groove. The first groove is located at the first point, and the second groove is located at the second point. Both the first groove and the second groove are separated from the diversion section by the first distance.

6. The resistor as claimed in claim 4, characterized in that, The current shunt includes an alloy resistor block having a negative temperature coefficient, and the copper busbar having a positive temperature coefficient.

7. The resistor as claimed in claim 4, characterized in that, The groove can be circular, elliptical, or rhomboid in shape.

8. A power distribution box, characterized in that, Including the resistor as described in any one of claims 1-7.

9. A vehicle, characterized in that, include: The power distribution box as described in claim 8; A battery pack, wherein the power distribution box is disposed within the battery pack; The control unit includes a voltage measurement pin, which is connected to a recess in the resistor.

10. A current measurement method, applied to the vehicle as described in claim 9, characterized in that, include: Connect the resistor in series to the current circuit to be measured; The total voltage of the shunt and the copper busbar is obtained through the voltage measurement pin; The loop current is calculated based on the total voltage and the nominal resistance value of the shunt section.

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