Current acquisition device and battery management system

Abstract

The utility model relates to a current acquisition device and a battery management system. The current acquisition device comprises a current guide assembly, the current guide assembly comprises a first current guide part, a second current guide part and a third current guide part, and the first current guide part, the second current guide part and the third current guide part are sequentially arranged at intervals; the resistor assembly comprises a first shunt resistor and a second shunt resistor, the two ends of the first shunt resistor are connected to the first flow guide part and the second flow guide part respectively, and the two ends of the second shunt resistor are connected to the second flow guide part and the third flow guide part respectively; and the circuit board is arranged above the resistor assembly and the flow guide assembly and is connected to the first flow guide part, the second flow guide part and the third flow guide part. The battery acquisition device does not need to add a switching copper bar and a connecting bolt, so that the cost of the battery acquisition device is reduced, additional high-voltage connecting points do not need to be added, and the reliability of the battery acquisition device is improved.

Description

Technical Field

[0001] This application relates to the technical field of battery management, and particularly to a current acquisition device and a battery management system. Background Art

[0002] A battery management system is an important unit that mainly ensures the safety and stability of battery applications by collecting battery voltage, temperature, current, etc. Among them, current is an important factor affecting the estimation accuracy of the state of charge (SOC). The accuracy of SOC estimation directly affects the safety during battery charging and discharging. If the SOC accuracy is too low, it may cause safety problems such as overcharging and over-discharging of the battery, affecting the life of the battery cells, and even leading to thermal runaway of the battery cells. Therefore, the detection of current during battery charging and discharging is particularly important.

[0003] In related technologies, due to the advantages of high precision, good linearity, low temperature drift, low noise interference, high resolution, and low price of shunt resistors, current acquisition devices often use shunt resistors to collect current. To improve the safety level of the battery management system, current acquisition devices often include two shunt resistors to avoid safety problems of the battery management system caused by the failure of one of the shunt resistors. However, when arranging two shunt resistors, the two shunt resistors need to be connected through connection bolts and adapter copper bars. This connection method increases the high-voltage connection points, reduces the reliability of the current acquisition device, and increases additional materials such as adapter copper bars and connection bolts, increasing the cost of the battery acquisition device. Summary of the Invention

[0004] Based on this, it is necessary to provide a current acquisition device and a battery management system for the above technical problems to improve the reliability of the battery acquisition device and reduce the cost of the battery acquisition device.

[0005] In a first aspect, this application provides a current acquisition device. The current acquisition device includes: a diversion component, which includes a first diversion member, a second diversion member, and a third diversion member, and the first diversion member, the second diversion member, and the third diversion member are arranged at intervals in sequence; a resistance component, which includes a first shunt resistor and a second shunt resistor. The first shunt resistor is disposed between the first diversion member and the second diversion member, and both ends of the first shunt resistor are respectively connected to the first diversion member and the second diversion member. The second shunt resistor is disposed between the second diversion member and the third diversion member, and both ends of the second shunt resistor are respectively connected to the second diversion member and the third diversion member; and a circuit board, which is disposed above the resistance component and the diversion component, and the circuit board is connected to the first diversion member, the second diversion member, and the third diversion member.

[0006] In one embodiment, a sampling circuit is provided on the circuit board. A first sampling point is provided at one end of the first current guiding member close to the first shunt resistor, and a second sampling point and a third sampling point are respectively provided at both ends of the second current guiding member. A fourth sampling point is provided at one end of the third current guiding member close to the second shunt resistor. The sampling circuit is connected to the first sampling point, the second sampling point, the third sampling point, and the fourth sampling point. The sampling circuit can obtain the voltage of the first shunt resistor through the first sampling point and the second sampling point, and obtain the voltage of the second shunt resistor through the third sampling point and the fourth sampling point.

[0007] In one embodiment, a first pad is provided on the lower surface of the circuit board. The welding end of the sampling circuit is disposed on the first pad. The first sampling point, the second sampling point, the third sampling point, and the fourth sampling point are all connected to the first pad.

[0008] In one embodiment, the current acquisition device further includes a connector. The connector is disposed above the circuit board. The sampling circuit further includes an output end, and the output end is connected to the connector.

[0009] In one embodiment, the current acquisition device further includes an NTC resistor. The NTC resistor is provided on the circuit board. The connector is connected to the NTC resistor. The NTC resistor can measure the temperature of the resistor component.

[0010] In one embodiment, a second pad is provided on the upper surface of the circuit board. The connector and the NTC resistor are both connected to the second pad.

[0011] In one embodiment, the connector is welded to the circuit board and forms a first solder joint on the second pad. The NTC resistor is welded to the circuit board and forms a second solder joint on the second pad. The current acquisition device further includes a protective coating, and the protective coating is coated on the first solder joint and the second solder joint.

[0012] In one embodiment, there are two NTC resistors. One is disposed above the first shunt resistor and can measure the temperature of the first shunt resistor, and the other is disposed above the second shunt resistor and can measure the temperature of the second shunt resistor.

[0013] In one embodiment, a first mounting hole is provided on the first current guiding member. The first mounting hole is disposed on the side of the first current guiding member away from the first shunt resistor. A second mounting hole is provided on the third current guiding member. The second mounting hole is disposed on the side of the third current guiding member away from the second shunt resistor.

[0014] In a second aspect, the present application provides a battery management system, and the battery management system includes the current acquisition device as described above.

[0015] The above battery acquisition device connects the two ends of the first shunt resistor to the first current guide and the second current guide respectively, and connects the two ends of the second shunt resistor to the second current guide and the third current guide respectively. Thus, the circuit board can acquire the voltage of the first shunt resistor through the first current guide and the second current guide, acquire the voltage of the second shunt resistor through the second current guide and the third current guide, calculate the current of the first shunt resistor by calculating the voltage and resistance value of the first shunt resistor, calculate the current of the second shunt resistor by calculating the voltage and resistance value of the second shunt resistor, avoid affecting the safety of the battery management system due to the acquisition failure of the first shunt resistor or the second shunt resistor, and this battery acquisition device does not need to add new transfer copper bars and connection bolts, reducing the cost of the battery acquisition device, and does not need to add additional high-voltage connection points, improving the reliability of the battery acquisition device. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the connection of two shunt resistors in the related art.

[0017] Figure 2 It is a schematic diagram of the current acquisition device in an embodiment of the present application. Detailed Embodiments

[0018] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0019] In the description of the present application, it should be understood that if terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0020] In addition, if the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0021] In this application, unless otherwise clearly specified and defined, if terms such as "installed", "connected", "linked", "fixed", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0022] In this application, unless otherwise clearly specified and defined, if there is a description such as a first feature being "on" or "under" a second feature, its meaning can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher horizontal level than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower horizontal level than the second feature.

[0023] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If so, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0024] Refer to Figure 1 , Figure 1The schematic diagram of the connection of two shunts 1 in the prior art is shown. In the prior art, when connecting two shunts 1, a transition copper bar 2 is directly connected to the two shunts 1. The two ends of the transition copper bar 2 are respectively connected to the current-carrying members of the two shunts 1 through two connecting bolts 3, so as to realize the connection of the two shunts 1, thereby increasing the safety of the battery management system and avoiding the influence on the acquisition of battery data due to the failure of a single shunt 1. However, the connection of the two shunts 1 requires the use of a transition copper bar 2 and two connecting bolts 3, with many components and complex tooling, increasing the weight of the battery management system and the difficulty of assembly.

[0025] Referring to Figure 2 , Figure 2 , the schematic diagram of a current acquisition device 100 in an embodiment of the present application is shown. In some embodiments, the current acquisition device 100 includes a current-carrying component, a resistance component, and a circuit board 30.

[0026] The current-carrying component is used for current transmission. The current-carrying component includes a first current-carrying member 11, a second current-carrying member 12, and a third current-carrying member 13, and the first current-carrying member 11, the second current-carrying member 12, and the third current-carrying member 13 are arranged at intervals in sequence. Optionally, the materials of the first current-carrying member 11, the second current-carrying member 12, and the third current-carrying member 13 are all purple copper, so that the current acquisition device 100 can have good overcurrent and heat dissipation performance. In other embodiments, the materials of the first current-carrying member 11, the second current-carrying member 12, and the third current-carrying member 13 can also be conductive materials with weldability such as brass, aluminum, or tinned steel.

[0027] The resistance component is used for current measurement. The resistance component includes a first shunt resistor 21 and a second shunt resistor 22. The first shunt resistor 21 is disposed between the first current-carrying member 11 and the second current-carrying member 12, and the two ends of the first shunt resistor 21 are respectively connected to the first current-carrying member 11 and the second current-carrying member 12. The second shunt resistor 22 is disposed between the second current-carrying member 12 and the third current-carrying member 13, and the two ends of the second shunt resistor 22 are respectively connected to the second current-carrying member 12 and the third current-carrying member 13.

[0028] Preferably, the materials of the first shunt resistor 21 and the second shunt resistor 22 are both manganese copper alloy. Manganese copper alloy has good temperature stability and low temperature coefficient, so that the resistance component can maintain a stable resistance value at different temperatures, ensuring the stability, accuracy, and reliability of the circuit.

[0029] The circuit board 30 is used for collecting the voltage of the resistance component and calculating the current of the resistance component through the voltage of the resistance component and the resistance value of the resistance component. The circuit board 30 is disposed above the resistance component and the current-carrying component, and the circuit board 30 is connected to the first current-carrying member 11, the second current-carrying member 12, and the third current-carrying member 13.

[0030] The two ends of the first shunt resistor 21 are respectively connected to the first current guiding member 11 and the second current guiding member 12, and the two ends of the second shunt resistor 22 are respectively connected to the second current guiding member 12 and the third current guiding member 13. Thus, the circuit board 30 can collect the voltage of the first shunt resistor 21 through the first current guiding member 11 and the second current guiding member 12, and collect the voltage of the second shunt resistor 22 through the second current guiding member 12 and the third current guiding member 13. By calculating the voltage and resistance value of the first shunt resistor 21, the current of the first shunt resistor 21 can be obtained, and by calculating the voltage and resistance value of the second shunt resistor 22, the current of the second shunt resistor 22 can be obtained, avoiding affecting the safety of the battery management system due to the acquisition failure of the first shunt resistor 21 or the second shunt resistor 22. And this battery acquisition device does not need to newly add a transfer copper row 2 and a connecting bolt 3, reducing the cost of the battery acquisition device, and does not need to newly add additional high-voltage connection points, improving the reliability of the battery acquisition device.

[0031] Further, a sampling circuit is provided on the circuit board 30. A first sampling point is provided at one end of the first current guiding member 11 close to the first shunt resistor 21, second sampling points and third sampling points are respectively provided at both ends of the second current guiding member 12, and a fourth sampling point is provided at one end of the third current guiding member 13 close to the second shunt resistor 22. The sampling circuit is connected to the first sampling point, the second sampling point, the third sampling point and the fourth sampling point. The sampling circuit can obtain the voltage of the first shunt resistor 21 through the first sampling point and the second sampling point and obtain the voltage of the second shunt resistor 22 through the third sampling point and the fourth sampling point, so as to obtain the current of the circuit through the voltage and resistance of the first shunt resistor 21 and the voltage and resistance value of the second shunt resistor 22.

[0032] Preferably, the resistance values of the first shunt resistor 21 and the second shunt resistor 22 are the same, so that the influence of the first shunt resistor 21 and the second shunt resistor 22 on the circuit is more balanced, which helps to maintain the stability of the circuit and helps to calculate the current of the circuit.

[0033] Feasibly, the thicknesses of the first shunt resistor 21 and the second shunt resistor 22 are less than the thicknesses of the first current guiding member 11, the second current guiding member 12 and the third current guiding member 13, so that there can be a gap between the first shunt resistor 21, the second shunt resistor 22 and the circuit board 30. Thus, the heat of the first shunt resistor 21 and the second shunt resistor 22 can be dissipated through the gap, improving the heat dissipation capacity of the current acquisition device 100.

[0034] In some embodiments, a first pad is provided on the lower surface of the circuit board 30. The welding end of the sampling circuit is disposed on the first pad. The first sampling point, the second sampling point, the third sampling point, and the fourth sampling point are connected to the first pad. Thus, the sampling circuit can collect the voltage of the first shunt resistor 21 through the first sampling point and the second sampling point and collect the voltage of the second shunt resistor 22 through the third sampling point and the fourth sampling point.

[0035] Specifically, the first current guiding member 11 includes a first connecting portion 111 and a first welding portion 112 connected to each other. The first connecting portion 111 is used to connect the battery module. The first welding portion 112 is closer to the first shunt resistor 21 than the first connecting portion 111. The first sampling point is disposed on the first welding portion 112. The first welding portion 112 is connected to the circuit board 30 and the first shunt resistor 21. Feasibly, the first welding portion 112 is connected to the first shunt resistor 21 by electron beam welding, and the first sampling point is welded to the first pad by a vapor phase flow welding process.

[0036] The second current guiding member 12 includes a second connecting portion 122, a second welding portion 121, and a third welding portion 123. The second welding portion 121 and the third welding portion 123 are respectively connected to two ends of the second connecting portion 122. The second sampling point is disposed on the second welding portion 121, and the third sampling point is disposed on the third welding portion 123. Feasibly, the second welding portion 121 is connected to the first shunt resistor 21 by electron beam welding, the third welding portion 123 is connected to the second shunt resistor 22 by electron beam welding, and the second sampling point and the third sampling point are welded to the first pad by a vapor phase flow welding process.

[0037] The third current guiding member 13 includes a third connecting portion 131 and a fourth welding portion 132 connected to each other. The third connecting portion 131 is used to connect the relay module. The fourth welding portion 132 is closer to the second shunt resistor 22 than the third connecting portion 131. The fourth sampling point is disposed on the fourth welding portion 132. The fourth welding portion 132 is connected to the circuit board 30 and the first shunt resistor 21. Feasibly, the fourth welding portion 132 is connected to the second shunt resistor 22 by electron beam welding, and the fourth sampling point is welded to the first pad by a vapor phase flow welding process.

[0038] Further, a first mounting hole 113 is provided on the first current guiding member 11. The first mounting hole 113 is disposed on the side of the first current guiding member 11 away from the first shunt resistor 21, that is, the first mounting hole 113 is provided on the first connecting portion 111. The first mounting hole 113 enables the first connecting portion 111 to be connected to the battery module; a second mounting hole 133 is provided on the third current guiding member 13. The second mounting hole 133 is disposed on the side of the first current guiding member 11 away from the second shunt resistor 22, that is, the second mounting hole 133 is provided on the third connecting portion 131. The second mounting hole 133 enables the third connecting portion 131 to be connected to the relay module, so that the current acquisition device 100 is configured on the circuit of the battery management system, and thus the current acquisition device 100 can acquire the current of the circuit.

[0039] In some embodiments, the current acquisition device 100 further includes a connector 40. The connector 40 is disposed above the circuit board 30. The sampling circuit further includes an output terminal, and the output terminal is connected to the connector 40. After being connected, the sampling circuit can transmit the voltages and temperature signals of the first shunt resistor 21 and the second shunt resistor 22 to the connector 40, and transmit them to the battery management system through the connector 40. The battery management system completes the correction of the resistance values of the first shunt resistor 21 and the second shunt resistor 22 and the calculation of the current.

[0040] Further, the current acquisition device 100 further includes an NTC resistor 50. The NTC resistor 50 is disposed on the circuit board 30. The connector 40 is connected to the NTC resistor 50. The NTC resistor 50 changes its resistance value with the change of temperature. Thus, the NTC resistor 50 can measure the temperature of the resistor component, and the battery management system can correct the resistance value of the resistor component through the temperature of the resistor component detected by the NTC resistor 50 to correct the temperature drift of the resistor component.

[0041] Specifically, two NTC resistors 50 are configured. One of them is disposed above the first shunt resistor 21 and can measure the temperature of the first shunt resistor 21, and the other is disposed above the second shunt resistor 22 and can measure the temperature of the second shunt resistor 22.

[0042] In some embodiments, a second pad is provided on the upper surface of the circuit board 30. Both the connector 40 and the NTC resistor 50 are connected to the second pad. Feasibly, both the connector 40 and the NTC resistor 50 are soldered to the second pad by SMT soldering. It should be noted that the present application does not limit the soldering processes of the current guiding component and the resistor component, the current guiding component and the circuit board 30, the connector 40 and the circuit board 30, and the NTC resistor 50 and the circuit board 30. One of the soldering processes such as ultrasonic soldering, resistance soldering, and laser soldering can be used for soldering.

[0043] Further, the connector 40 is welded to the circuit board 30 to form a first solder joint on the second pad, the NTC resistor 50 is welded to the circuit board 30, and a second solder joint is formed on the second pad. The current acquisition device 100 further includes a protective coating (not shown), and the protective coating is coated on the first solder joint and the second solder joint to protect the first solder joint and the second solder joint.

[0044] Preferably, the protective coating is a three-proof paint. The three-proof paint usually has the characteristics of moisture-proof and dust-proof, and can effectively protect the solder joints from the influence of a humid environment or dust, improving the reliability and stability of the circuit. The three-proof paint can effectively resist corrosion, play a good protective role for the solder joints, extend the service life of the connector 40, the NTC resistor 50 and the circuit board 30, has good insulation performance, and the three-proof paint can prevent short circuits or leakage between the solder joints or between the solder joints and the surrounding environment, improving the safety of the circuit.

[0045] As the same concept, on the other hand, the present application provides a battery management system. The battery management system includes a current acquisition device 100, and the current acquisition device 100 is the current acquisition device 100 in the above embodiment.

[0046] Through the arrangement of the diversion component and the resistance component, the battery management system avoids the safety problems of the battery management system caused by the failure of one of the shunt resistors, and there is no need to newly add the connecting bolt 3 and the adapter copper bar 2, reducing the overall cost of the current acquisition device 100, and further helping to reduce the overall weight of the battery management system and shorten the assembly time of the battery management system.

[0047] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0048] The above embodiments only represent several implementation manners of the present application, and the description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A current collection device, characterized in that: The current collection device comprises: A flow guide assembly, the flow guide assembly comprising a first flow guide member, a second flow guide member and a third flow guide member, wherein the first flow guide member, the second flow guide member and the third flow guide member are arranged in sequence and at intervals; a resistor assembly, the resistor assembly comprising a first shunt resistor and a second shunt resistor, the first shunt resistor being arranged between the first flow guide and the second flow guide, and the two ends of the first shunt resistor being respectively connected to the first flow guide and the second flow guide, the second shunt resistor being arranged between the second flow guide and the third flow guide, and the two ends of the second shunt resistor being respectively connected to the second flow guide and the third flow guide; and A circuit board is arranged above the resistor component and the flow guide component and is connected to the first flow guide member, the second flow guide member and the third flow guide member.

2. The current collection device according to claim 1, characterized in that: A sampling circuit is provided on the circuit board, a first sampling point is provided on one end of the first flow guide member close to the first shunt resistor, a second sampling point and a third sampling point are provided at both ends of the second flow guide member, a fourth sampling point is provided on one end of the third flow guide member close to the second shunt resistor, the sampling circuit is connected to the first sampling point, the second sampling point, the third sampling point and the fourth sampling point, and the sampling circuit can obtain the voltage of the first shunt resistor through the first sampling point and the second sampling point and obtain the voltage of the second shunt resistor through the third sampling point and the fourth sampling point.

3. The current collection device according to claim 2, characterized in that: A first pad is provided on the lower surface of the circuit board, a welding end of the sampling circuit is arranged on the first pad, and the first sampling point, the second sampling point, the third sampling point and the fourth sampling point are all connected to the first pad.

4. The current collection device according to claim 2, characterized in that: The current collection device further includes a connector, which is arranged above the circuit board. The sampling circuit further includes an output end, which is connected to the connector.

5. The current collection device according to claim 4, characterized in that: The current collection device further includes an NTC resistor, which is disposed on the circuit board, the connector is connected to the NTC resistor, and the NTC resistor can measure the temperature of the resistor component.

6. The current collection device according to claim 5, characterized in that: A second pad is provided on the upper surface of the circuit board, and the connector and the NTC resistor are both connected to the second pad.

7. The current collection device according to claim 6, characterized in that: The connector is welded to the circuit board and forms a first welding point on the second welding pad, and the NTC resistor is welded to the circuit board and forms a second welding point on the second welding pad; the current collection device also includes a protective coating, and the protective coating is applied to the first welding point and the second welding point.

8. The current collection device according to claim 5, characterized in that: The NTC resistors are configured with two, one of which is arranged above the first shunt resistor and can measure the temperature of the first shunt resistor, and the other is arranged above the second shunt resistor and can measure the temperature of the second shunt resistor.

9. The current collection device according to claim 1, characterized in that: The first flow guide is provided with a first mounting hole, which is arranged on a side of the first flow guide away from the first shunt resistor; the third flow guide is provided with a second mounting hole, which is arranged on a side of the third flow guide away from the second shunt resistor.

10. A battery management system, characterized in that: The battery management system comprises the current acquisition device according to any one of claims 1-9.

Images