Current sampling circuit, battery management system, battery device and electric equipment

Abstract

The embodiment of the utility model provides a current sampling circuit, a battery management system, a battery device and electric equipment, and the current sampling circuit comprises a diverter which is connected with a detected battery cell group in series; the sampling chip is connected with the diverter in parallel and is used for collecting the voltage at the two ends of the diverter and determining the current flowing through the detected battery cell group based on the collected voltage; the first bidirectional protection assembly is connected in parallel between the diverter and the first sampling pin and is used for performing overvoltage protection on the first sampling pin in positive and negative directions; the second bidirectional protection assembly is connected in parallel between the diverter and the second sampling pin and is used for performing overvoltage protection on the second sampling pin in positive and negative directions; the first filtering assembly is connected between the bidirectional protection assembly and the flow divider in series and used for filtering common-mode noise at the two ends of the flow divider. Therefore, the safety and reliability of the current sampling circuit can be improved, faults caused by transient overvoltage and common-mode interference are reduced, and the precision of current sampling is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a current sampling circuit, a battery management system, a battery device and a power consumption equipment. BACKGROUND

[0002] This section is intended to provide background or context to the embodiments of the present application. The description herein does not constitute admission that the information provided herein is prior art.

[0003] New energy batteries are increasingly widely used in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also increasingly used in the field of energy storage and the like.

[0004] In a battery device, a current sampling circuit is a key link for realizing control and protection of a battery management system. In particular, in high-reliability application scenarios such as new energy vehicles and industrial power supplies, higher requirements are put forward for the accuracy and stability of current measurement. A common current sampling method usually adopts a shunt resistor (Shunt Resistor) in cooperation with a sampling chip to calculate the current value flowing through the circuit by detecting the voltage across the shunt resistor. However, in actual application scenarios, the safety and reliability of the current sampling circuit will be affected due to the existence of internal and external interference and the like. UTILITY MODEL CONTENT

[0005] Therefore, the embodiments of the present application expect to provide a current sampling circuit, a battery management system, a battery device and a power consumption equipment, which can effectively improve the safety and reliability of the current sampling circuit, reduce faults caused by transient overvoltage and common-mode interference, and improve the accuracy of current sampling.

[0006] The technical scheme of the embodiments of the present application is implemented as follows:

[0007] The embodiments of the present application provide a current sampling circuit, comprising:

[0008] a shunt resistor connected in series with a measured battery pack;

[0009] a sampling chip connected in parallel with the shunt resistor through a first sampling pin and a second sampling pin, configured to collect the voltage across the shunt resistor and determine the current flowing through the measured battery pack based on the collected voltage;

[0010] a bidirectional protection assembly, comprising a first bidirectional protection assembly and a second bidirectional protection assembly, the first bidirectional protection assembly being connected in parallel between the shunt resistor and the first sampling pin and configured to perform overvoltage protection in positive and negative directions on the first sampling pin, and the second bidirectional protection assembly being connected in parallel between the shunt resistor and the second sampling pin and configured to perform overvoltage protection in positive and negative directions on the second sampling pin;

[0011] The first filter assembly, connected in series between the bidirectional protection assembly and the splitter, is used to filter common-mode noise at both ends of the splitter.

[0012] Based on the aforementioned technical means, on the one hand, by setting up a first bidirectional protection component and a second bidirectional protection component to provide overvoltage protection for the first and second sampling pins in both positive and negative directions, the risk of transient overvoltages in both directions damaging the sampling chip can be effectively reduced, thus improving the safety and reliability of the current sampling circuit. On the other hand, the first filtering component can suppress common-mode noise at both ends of the shunt, thereby reducing the impact of interference signals on the current sampling accuracy and reducing the risk of the bidirectional protection component being broken down and conducting, thereby reducing the probability of inconsistency between the conduction states of the first and second bidirectional protection components, and further reducing sampling current jump problems. Thus, the safety and reliability of the current sampling circuit can be effectively improved, faults caused by transient overvoltages and common-mode interference can be reduced, and the accuracy of current sampling can be improved.

[0013] In some embodiments, the reference ground pin of the sampling chip is connected to the negative terminal of the battery cell group under test, and the shunt is connected to the negative terminal of the battery cell group under test via a connector.

[0014] The first end of the first bidirectional protection component is connected between the second end of the shunt and the first sampling pin, and the third end of the first bidirectional protection component is connected at the same potential to the reference ground pin.

[0015] The fourth terminal of the second bidirectional protection component is connected between the fifth terminal of the shunt and the second sampling pin, and the sixth terminal of the second bidirectional protection component is connected at the same potential to the reference ground pin.

[0016] Based on the aforementioned technical means, on the one hand, connecting the shunt to the negative terminal of the tested battery cell assembly via a connector improves the flexibility of the connection between the current sampling circuit and the tested battery cell assembly, providing support for integrating multiple sampling functions into the sampling chip. On the other hand, connecting the reference ground pin of the sampling chip to the negative terminal of the tested battery cell assembly, and connecting the other end of the bidirectional protection component to the reference ground pin at the same potential, further enhances the overvoltage protection effect of the sampling pin and improves the anti-interference capability of the entire circuit. Furthermore, by setting up a first bidirectional protection component and a second bidirectional protection component to provide positive and negative overvoltage protection for the first and second sampling pins respectively, the risk of damage to the sampling chip caused by transient overvoltages in the positive and negative directions due to voltage drop caused by the self-inductance reactance of the connector during the charging and discharging process of the battery cell assembly can be reduced, further improving the safety and reliability of the current sampling circuit.

[0017] In some embodiments, the first bidirectional protection component includes a first bidirectional transient voltage suppressor, and the second bidirectional protection component includes a second bidirectional transient voltage suppressor.

[0018] Based on the above technical means, a bidirectional transient voltage suppressor (TVS) is used as a protection device, which can absorb transient overvoltages in both positive and negative directions. Compared with a unidirectional TVS, it has a more comprehensive protection effect. Especially in complex electromagnetic environments such as bulk current injection (BCI) testing, it can effectively reduce the current sampling error caused by the inconsistent conduction of TVS at both ends of the shunt, and improve the robustness of the current sampling circuit.

[0019] In some embodiments, the first filtering component includes a first inductor and a second inductor in common mode, the first inductor being connected in series between a first end of the first bidirectional protection component and a second end of the shunt, and the second inductor being connected in series between a fourth end of the second bidirectional protection component and a fifth end of the shunt.

[0020] Based on the above technical means, using a common-mode inductor as a filtering element can effectively suppress high-frequency common-mode noise while having little impact on differential-mode signals, thereby improving the anti-interference performance of the current sampling circuit while ensuring the accuracy of current sampling.

[0021] In some embodiments, the first filter assembly includes a first magnetic bead and a second magnetic bead, the first magnetic bead being connected in series between a first end of the first bidirectional protection assembly and a second end of the splitter, and the second magnetic bead being connected in series between a fourth end of the second bidirectional protection assembly and a fifth end of the splitter.

[0022] Based on the above technical means, ferrite beads are used as filtering elements. Since ferrite beads have high impedance to high-frequency noise, they can effectively filter out high-frequency common-mode noise and suppress common-mode interference. They are especially suitable for application scenarios with a lot of high-frequency pulse noise, which further improves the stability and accuracy of current sampling.

[0023] In some embodiments, the current sampling circuit further includes:

[0024] The second filtering component includes a first filter and a second filter. The first filter is disposed between the first bidirectional protection component and the first sampling pin, and the second filter is disposed between the second bidirectional protection component and the second sampling pin.

[0025] Based on the above technical means, by setting a filter between the bidirectional protection component and the sampling pin, residual interference noise is further filtered out, improving the purity of the sampling signal, thereby improving the accuracy and stability of current measurement.

[0026] In some embodiments, the first filter includes a first resistor and a first capacitor. The first resistor is connected in series between the first bidirectional protection component and the first sampling pin. One end of the first capacitor is connected between the first resistor and the first sampling pin, and the other end of the first capacitor is connected at the same potential as the reference ground pin.

[0027] The second filter includes a second resistor and a second capacitor. The second resistor is connected in series between the second bidirectional protection component and the second sampling pin. One end of the second capacitor is connected between the second resistor and the second sampling pin, and the other end of the second capacitor is connected at the same potential to the reference ground pin.

[0028] Based on the above technical means, by setting a resistor-capacitor (RC) filter between the bidirectional protection component and the sampling pin, high-frequency noise can be effectively filtered out, which can further enhance the current sampling circuit's ability to suppress interference and improve the overall reliability of the circuit.

[0029] This application provides a battery management system, which includes the current sampling circuit described in the above embodiments.

[0030] This application provides a battery device that includes the battery management system described in the above embodiments.

[0031] This application provides an electrical device that includes the battery device described in the above embodiments. Attached Figure Description

[0032] Figure 1 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure One ;

[0033] Figure 2 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Two ;

[0034] Figure 3 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Three ;

[0035] Figure 4 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Four ;

[0036] Figure 5 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Five ;

[0037] Figure 6 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Six ;

[0038] Figure 7 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Seven ;

[0039] Figure 8 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Eight ;

[0040] Figure 9 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Nine ;

[0041] Figure 10 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Ten ;

[0042] Figure 11 A schematic diagram of the composition structure of a battery management system provided in an embodiment of this application;

[0043] Figure 12 This is a schematic diagram of the composition structure of a battery device provided in an embodiment of this application;

[0044] Figure 13 This is a schematic diagram of the composition structure of an electrical device provided in an embodiment of this application. Detailed Implementation

[0045] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific implementation should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof are intended to cover non-exclusive inclusion.

[0047] In the description of the embodiments of this application, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0048] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0049] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0050] With the development of clean energy, more and more devices are using electricity as their driving force, leading to the rapid development of power batteries, such as lithium-ion batteries, which can store large amounts of electrical energy and can be repeatedly charged and discharged. These power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. As the application areas of power batteries continue to expand, the market demand is also constantly increasing.

[0051] In this embodiment, the battery device can be manufactured from battery cells and / or battery modules. A battery cell refers to a single battery cell, which is the basic unit capable of converting chemical energy into electrical energy. It can be used to manufacture battery modules or battery devices to supply power to electrical devices. A single battery cell can be a primary battery or a secondary battery. A secondary battery is a battery cell that can be recharged after discharge to reactivate its active materials and continue to be used. Battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, or lead-acid batteries, etc., and this embodiment is not limited to these types. A single battery cell can be cylindrical, cuboid, or other shapes.

[0052] A battery cell includes an electrode assembly, which comprises a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator is positioned between the positive and negative electrodes to prevent short circuits while allowing active ions to pass through.

[0053] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0054] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0055] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0056] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0057] Liquid electrolytes include electrolyte salts and solvents.

[0058] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0059] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0060] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0061] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0062] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0063] In some implementations, the electrode assembly is a stacked structure.

[0064] In battery devices, a current sampling circuit is included to collect and process the current of the battery cells. Current sampling circuits in related technologies typically employ a shunt in conjunction with a sampling chip. During the charging and discharging process of the battery device, the current flowing through the circuit is calculated by detecting the voltage across the shunt. However, in practical applications, the safety and reliability of the current sampling circuit can be affected by factors such as internal and external interference. For example, under pulsed current conditions, transient overvoltages and / or common-mode interference may occur on the current sampling pins of the sampling chip, leading to a series of safety and reliability issues.

[0065] Based on this, embodiments of this application provide a current sampling circuit, a battery management system, a battery device, and an electrical device, which can effectively improve the safety and reliability of the current sampling circuit, reduce faults caused by transient overvoltage and common-mode interference, and improve the accuracy of current sampling.

[0066] The following section explains some key terms and concepts involved in the embodiments of this application, in order to better understand the technical solution and innovations of this application.

[0067] 1) Shunt: A resistive element used to measure current, typically with low resistance. When current flows through a shunt, a voltage drop is generated across its terminals. This voltage drop is proportional to the current, so the current value can be calculated by measuring this voltage.

[0068] 2) A bidirectional TVS is an electronic device capable of absorbing transient overvoltages in both positive and negative directions. Compared to a unidirectional TVS, a bidirectional TVS can provide overvoltage protection over a wider voltage range, making it suitable for systems with pulse current conditions, thereby reducing the risk of damage to the sampling chip due to electrostatic overstress (EOS).

[0069] 3) Common-mode inductor: This consists of two common-mode inductors with their coils wound on the same magnetic core, having the same number of turns and phase. A common-mode inductor is a passive component used to suppress common-mode noise. It presents high impedance to common-mode signals and low impedance to differential-mode signals, thus effectively filtering out high-frequency common-mode interference without affecting the transmission of normal signals. In current sampling circuits, common-mode inductors can be used to improve the system's anti-interference capability.

[0070] 4) Ferrite Beads: Electronic components with high frequency impedance characteristics, which can be used to suppress high-frequency noise. Ferrite beads exhibit low impedance at low frequencies and high impedance at high frequencies, thus effectively absorbing high-frequency common-mode noise and improving signal purity and stability.

[0071] 5) RC Filter: A filter circuit consisting of a resistor and a capacitor, used to filter out high-frequency noise. In an RC filter, the parameters of the resistor and capacitor can be adjusted according to actual needs to optimize the filtering effect and improve sampling accuracy without affecting the dynamic response.

[0072] 6) Analog Front End (AFE) chip: This is the core component in the battery management system used to acquire and process analog signals.

[0073] 7) EOS (Electrostatic Over Stress): This is a common cause of electronic component failure. When the input terminal of an AFE chip is subjected to transient overvoltage, it may cause the internal circuitry to burn out, resulting in permanent chip damage and seriously affecting the reliability and safety of the system.

[0074] 8) Bulk Current Injection (BCI) Test: This is a test method used to evaluate the electromagnetic compatibility of electronic equipment. During this test, transient overvoltages or high-frequency noise may be introduced into the circuit, affecting the accuracy and stability of current sampling.

[0075] Figure 1 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure One ,like Figure 1 As shown, the current sampling circuit 10 includes:

[0076] Shunt 11 is connected in series with the battery cell group 20 under test;

[0077] The sampling chip 12 is connected in parallel with the shunt 11 through the first sampling pin 12a and the second sampling pin 12b. It is used to collect the voltage across the shunt 11 and determine the current flowing through the battery cell group 20 under test based on the collected voltage.

[0078] The bidirectional protection component 13 includes a first bidirectional protection component 131 and a second bidirectional protection component 132. The first bidirectional protection component 131 is connected in parallel between the shunt 11 and the first sampling pin 12a and is used to provide overvoltage protection for the first sampling pin 12a in both positive and negative directions. The second bidirectional protection component 132 is connected in parallel between the shunt 11 and the second sampling pin 12b and is used to provide overvoltage protection for the second sampling pin 12b in both positive and negative directions.

[0079] The first filter component 14 is connected in series between the bidirectional protection component 13 and the splitter 11 to filter the common-mode noise at both ends of the splitter 11.

[0080] Understandably, shunt 11 is a low-resistance resistor, typically made of materials such as copper or manganese-copper alloy. When current flows through the shunt 11, a voltage drop proportional to the current is generated across it. By measuring this voltage drop, the current flowing through the battery cell assembly can be calculated. For example, in the battery pack of a new energy vehicle, shunt 11 can be installed in the negative terminal circuit as one of the core components for current sampling. Because the resistance of shunt 11 is very small, it does not cause a significant voltage drop in the main circuit, while still providing a sufficiently accurate voltage signal for subsequent processing.

[0081] In practical implementation, the selection of the shunt 11 can take into account factors such as the shunt's rated power, temperature coefficient, and long-term stability, so that the shunt 11 can provide a reliable sampling signal under different operating conditions. In some embodiments, the installation location of the shunt 11 should also avoid the influence of electromagnetic interference; proper arrangement can improve the overall system's anti-interference capability.

[0082] The sampling chip 12 can be any suitable chip capable of acquiring the voltage across the shunt 11 and determining the current flowing through the battery cell assembly 20 under test based on the acquired voltage. For example, the sampling chip 12 can include, but is not limited to, an AFE chip.

[0083] The tested battery cell group 20 may include one or more battery cells, and multiple battery cells may be connected in series or in parallel.

[0084] The first sampling pin 12a and the second sampling pin 12b are respectively connected to the two terminals of the shunt 11. The first sampling pin 12a and the second sampling pin 12b are used to obtain the voltage across the shunt 11 to obtain the corresponding voltage difference. Based on the voltage difference across the shunt 11, the current value flowing through the tested battery cell assembly 20 can be calculated.

[0085] The bidirectional protection component 13 refers to an electronic component that can provide overvoltage protection in both positive and negative directions, and may include, but is not limited to, bidirectional TVS and / or bidirectional thyristors. For example, a bidirectional TVS can quickly conduct in both forward and reverse overvoltage situations, clamping the voltage to a set safe voltage to absorb transient overvoltages, limit voltage rise, and protect the circuit. Similarly, a bidirectional thyristor can form a low-resistance path after detecting overvoltage, dissipating excess energy and protecting sensitive components from damage.

[0086] In some implementations, both the first bidirectional protection component 131 and the second bidirectional protection component 132 are bidirectional TVS devices, capable of absorbing transient overvoltages in both positive and negative directions, thereby comprehensively protecting the sampling chip from EOS (Effective Voltage Regulator). Compared to traditional unidirectional TVS, bidirectional TVS offers a wider protection range, making it particularly suitable for scenarios involving pulsed currents. For example, during BCI testing, transient overvoltages or high-frequency noise may be introduced. In such cases, the first bidirectional protection component 131 and the second bidirectional protection component 132 can quickly respond to and absorb these abnormal voltages, preventing them from affecting the normal operation of the sampling chip.

[0087] In actual implementation, the selection of the first bidirectional protection component 131 and the second bidirectional protection component 132 needs to be optimized based on factors such as the operating voltage range of the sampling chip, the maximum allowable clamping voltage, and the response time, so as to ensure that the first bidirectional protection component 131 and the second bidirectional protection component 132 can provide stable overvoltage protection under various extreme working conditions.

[0088] The primary function of the first filtering component 14 is to suppress common-mode noise and improve the anti-interference capability of current sampling. The first filtering component 14 presents a high impedance to common-mode signals and a low impedance to differential-mode signals, thus effectively filtering out common-mode interference without affecting the transmission of normal signals. For example, the first filtering component 14 may include, but is not limited to, at least one of a common-mode inductor, a ferrite bead, etc.

[0089] In actual implementation, the parameters of the first filtering component 14 can be adjusted according to the frequency characteristics of the current sampling circuit (such as the noise frequency band to be filtered out) so as to suppress common-mode interference without causing excessive attenuation of the differential-mode signal.

[0090] Based on the aforementioned technical means, on the one hand, by setting up a first bidirectional protection component and a second bidirectional protection component to provide overvoltage protection for the first and second sampling pins in both positive and negative directions, the risk of transient overvoltages in both directions damaging the sampling chip can be effectively reduced, thus improving the safety and reliability of the current sampling circuit. On the other hand, the first filtering component can suppress common-mode noise at both ends of the shunt, thereby reducing the impact of interference signals on the current sampling accuracy and reducing the risk of the bidirectional protection component being broken down and conducting, thereby reducing the probability of inconsistency between the conduction states of the first and second bidirectional protection components, and further reducing sampling current jump problems. Thus, the safety and reliability of the current sampling circuit can be effectively improved, faults caused by transient overvoltages and common-mode interference can be reduced, and the accuracy of current sampling can be improved.

[0091] In some embodiments, such as Figure 2 As shown, the reference ground pin 12c of the sampling chip 12 is connected to the negative terminal of the battery cell group 20 under test, and the shunt 11 is connected to the negative terminal of the battery cell group 20 under test through the connector 30.

[0092] The first end 131a of the first bidirectional protection component 131 is connected between the second end 11a of the shunt 11 and the first sampling pin 12a, and the third end 131b of the first bidirectional protection component 131 is connected at the same potential to the reference ground pin 12c.

[0093] The fourth terminal 132a of the second bidirectional protection component 132 is connected between the fifth terminal 11b of the shunt 11 and the second sampling pin 12b, and the sixth terminal 132b of the second bidirectional protection component 132 is connected at the same potential to the reference ground pin 12c.

[0094] The reference ground pin 12c of the sampling chip 12 is an important terminal used to define the zero voltage reference point in the circuit system. The reference ground pin 12c of the sampling chip 12 is connected to the negative terminal of the battery cell group 20 under test to ensure the stability of the sampling signal.

[0095] The connector 30 can be made of a material with low resistance, such as a wire, solder joint, copper busbar, or copper bar, and is used to reliably connect one end of the shunt to the negative terminal of the battery pack.

[0096] Understandably, in order to ensure measurement accuracy, the shunt 11 must have a good electrical connection with the negative terminal of the battery cell assembly 20 under test, so as to avoid errors caused by poor contact or parasitic resistance in the electrical connection between the shunt 11 and the battery cell assembly 20 under test.

[0097] By connecting the reference ground pin 12c of the sampling chip 12 to the negative terminal of the battery cell group 20 under test, and using the connector 30 to reliably connect the shunt 11 to the negative terminal of the battery cell group 20 under test, the common-mode noise of the first sampling pin 12a and the second sampling pin 12b can be effectively reduced, thereby improving the stability and accuracy of current sampling.

[0098] It should be noted that the first end 131a of the first bidirectional protection component 131 is connected between the second end 11a of the shunt 11 and the first sampling pin 12a, while the third end 131b of the first bidirectional protection component 131 is at the same potential as the reference ground pin 12c, forming a symmetrical protection loop. Similarly, the second bidirectional protection component 132 is connected in a similar manner between the fifth end 11b of the shunt 11 and the second sampling pin 12b, and the sixth end 132b of the second bidirectional protection component 132 is at the same potential as the reference ground pin 12c. The arrangement of the first bidirectional protection component 131 and the second bidirectional protection component 132 ensures that regardless of the direction of the transient overvoltage, the voltage can be quickly absorbed and discharged to ground, thereby effectively preventing damage to the sampling chip.

[0099] Based on the aforementioned technical means, on the one hand, connecting the shunt to the negative terminal of the tested battery cell assembly via a connector improves the flexibility of the connection between the current sampling circuit and the tested battery cell assembly, providing support for integrating multiple sampling functions into the sampling chip. On the other hand, connecting the reference ground pin of the sampling chip to the negative terminal of the tested battery cell assembly, and connecting the other end of the bidirectional protection component to the reference ground pin at the same potential, further enhances the overvoltage protection effect of the sampling pin and improves the anti-interference capability of the entire circuit. Furthermore, by setting up a first bidirectional protection component and a second bidirectional protection component to provide positive and negative overvoltage protection for the first and second sampling pins respectively, the risk of damage to the sampling chip caused by transient overvoltages in the positive and negative directions due to voltage drop caused by the self-inductance reactance of the connector during the charging and discharging process of the battery cell assembly can be reduced, further improving the safety and reliability of the current sampling circuit.

[0100] In some embodiments, such as Figure 3 As shown, the sampling chip 12 also includes at least one third sampling pin 12d, which is used to acquire the voltage of at least one cell in the battery cell group 20 under test.

[0101] In this embodiment, the sampling chip 12 not only has current sampling capability, but also voltage sampling function, so as to realize independent monitoring of the voltage of a single cell.

[0102] Based on the above technical means, by adding a third sampling pin, the sampling chip can not only collect current information, but also cell voltage, realizing comprehensive monitoring of multiple parameters, which is conducive to improving the overall control accuracy and safety of the battery management system.

[0103] In some embodiments, such as Figure 4 As shown, the first bidirectional protection component 131 includes a first bidirectional transient voltage suppressor (TVS1), and the second bidirectional protection component 132 includes a second bidirectional transient voltage suppressor (TVS2).

[0104] Understandably, the first bidirectional transient voltage suppressor (TVS1) and the second bidirectional transient voltage suppressor (TVS2) can absorb overvoltage energy in both positive and negative directions, thereby preventing the AFE chip from being damaged by EOS. In the battery management system, the first bidirectional transient voltage suppressor (TVS1) and the second bidirectional transient voltage suppressor (TVS2) can effectively address the potential mismatch problem caused by the copper contacts and other connections between the negative terminal of the tested cell group 20 and the shunt 11.

[0105] For example, in the BMS system of new energy vehicles, when the large current changes rapidly, the copper bars and other connecting parts between the negative terminal of the tested battery cell group 20 and the shunt 11 may generate a large voltage drop due to self-inductance reactance, which may lead to transient overvoltage at the current sampling pin of the AFE chip. When the voltage drop is caused by the rapid change of large current, the first bidirectional transient voltage suppressor TVS1 and the second bidirectional transient voltage suppressor TVS2 can quickly respond and absorb the overvoltage energy, thereby reducing the risk of damage to the AFE chip.

[0106] Based on the above technical means, using a bidirectional TVS as a protective device can absorb transient overvoltage in both positive and negative directions. Compared with a unidirectional TVS, it has a more comprehensive protection effect. Especially in complex electromagnetic environments such as BCI testing, it can effectively reduce the current sampling error caused by the inconsistent conduction of TVS at both ends of the shunt, and improve the robustness of the current sampling circuit.

[0107] In some embodiments, such as Figure 5 As shown, the first filter assembly 14 includes a common-mode first inductor L1 and a second inductor L2. The first inductor L1 is connected in series between the first end 131a of the first bidirectional protection assembly 131 and the second end 11a of the shunt 11. The second inductor L2 is connected in series between the fourth end 132a of the second bidirectional protection assembly 132 and the fifth end 11b of the shunt 11.

[0108] Here, common-mode noise refers to the voltage or current signal with the same direction and amplitude relative to ground between two conductors in a circuit. In the embodiments of this application, common-mode noise is caused by electromagnetic interference (EMI) and is typically present on power lines and signal lines. Common-mode noise affects the sampling accuracy of the sampling chip. Using two common-mode inductors as part of the first filtering component can suppress common-mode noise.

[0109] It is understandable that the first inductor L1 and the second inductor L2 together form a common-mode filter circuit. This common-mode filter circuit can effectively suppress common-mode noise in both positive and negative directions without affecting the transmission of normal current signals. In actual implementation, the first inductor L1 and the second inductor L2 are located in different branches, but they work together to achieve bidirectional common-mode noise suppression, thus improving the overall filtering effect.

[0110] By connecting the first inductor L1 in series between the first terminal 131a of the first bidirectional protection component 131 and the second terminal 11a of the shunt 11, and connecting the second inductor L2 between the fourth terminal 132a of the second bidirectional protection component 132 and the fifth terminal 11b of the shunt 11, high-frequency noise can be further filtered out before the signal passes through the first bidirectional protection component 131 and the second bidirectional protection component 132, reducing the risk of interference signals breaking down the first bidirectional protection component 131 and the second bidirectional protection component 132, thereby protecting the normal operation of the sampling chip.

[0111] Based on the above technical means, using a common-mode inductor as a filtering element can effectively suppress high-frequency common-mode noise while having little impact on differential-mode signals, thereby improving the anti-interference performance of the current sampling circuit while ensuring the accuracy of current sampling.

[0112] In some embodiments, such as Figure 6 As shown, the first filter assembly 14 includes a first magnetic bead FB1 and a second magnetic bead FB2. The first magnetic bead FB1 is connected in series between the first end 131a of the first bidirectional protection assembly 131 and the second end 11a of the diverter 11. The second magnetic bead FB2 is connected in series between the fourth end 132a of the second bidirectional protection assembly 132 and the fifth end 11b of the diverter 11.

[0113] The first ferrite bead FB1 and the second ferrite bead FB2 are electronic components with high impedance characteristics, which can be used to suppress high-frequency noise, especially common-mode noise. The first ferrite bead FB1 and the second ferrite bead FB2 can be made of ferrite material, exhibiting low impedance at low frequencies and significantly increasing impedance at high frequencies, thereby effectively absorbing and suppressing high-frequency interference signals. The first ferrite bead FB1 and the second ferrite bead FB2 can isolate high-frequency noise in the current sampling circuit, helping to improve the sampling accuracy of the sampling chip and the system stability. Depending on the actual operating conditions, the first ferrite bead FB1 and the second ferrite bead FB2 with different resistance values ​​and frequency characteristics can be selected to optimize the filtering effect; this application does not limit this.

[0114] The first ferrite bead FB1 and the second ferrite bead FB2 are arranged on different paths, which can independently suppress common-mode noise on two independent signal paths, thereby enhancing the anti-interference capability of the entire system.

[0115] Understandably, compared to using common-mode inductors, using ferrite beads not only simplifies the circuit structure and reduces manufacturing costs, but also improves the overall circuit reliability. Furthermore, compared to common-mode inductors, ferrite beads can filter out higher-frequency noise. In addition, ferrite beads are smaller in size, making them easier to integrate into compact circuit boards, which suits the space utilization requirements of modern BMS (Browser Management Systems).

[0116] The first magnetic bead FB1 is connected in series between the first end 131a of the first bidirectional protection component 131 and the second end 11a of the shunt 11. The first magnetic bead FB1 can further filter out high-frequency noise before the signal passes through the first bidirectional protection component 131, reduce the risk of interference signal breaking down the first bidirectional protection component 131, and thus protect the normal operation of the sampling chip.

[0117] Similarly, by connecting the second ferrite bead FB2 between the fourth end 132a of the second bidirectional protection component 132 and the fifth end 11b of the shunt 11, the second ferrite bead FB2 can further filter out high-frequency noise before the signal passes through the second bidirectional protection component 132, reducing the risk of interference signals breaking down the second bidirectional protection component 132, thereby protecting the normal operation of the sampling chip.

[0118] In some implementations, considering that the overcurrent capability of the magnetic beads may not be strong enough, a third bidirectional TVS can be set between the first magnetic bead FB1 and the shunt 11, and a fourth bidirectional TVS can be set between the second magnetic bead FB2 and the shunt 11 to provide surge protection for the first magnetic bead FB1 and the second magnetic bead FB2, thereby further improving the safety and stability of the current sampling circuit.

[0119] Based on the above technical means, ferrite beads are used as filtering elements. Since ferrite beads have high impedance to high-frequency noise, they can effectively filter out high-frequency common-mode noise and suppress common-mode interference. They are especially suitable for application scenarios with a lot of high-frequency pulse noise, which further improves the stability and accuracy of current sampling.

[0120] In some embodiments, such as Figure 7 As shown, the current sampling circuit 10 also includes:

[0121] The second filtering component 15 includes a first filter 151 and a second filter 152. The first filter 151 is disposed between the first bidirectional protection component 131 and the first sampling pin 12a, and the second filter 152 is disposed between the second bidirectional protection component 132 and the second sampling pin 12b.

[0122] The second filtering component 15 can be used to further suppress high-frequency noise and improve the accuracy and stability of current sampling. In the second filtering component 15, the first filter 151 and the second filter 152 correspond to the first bidirectional protection component 131 and the second bidirectional protection component 132, respectively. The first filter 151 is connected between the first bidirectional protection component 131 (e.g., bidirectional TVS) and the first sampling pin 12a of the sampling chip 12, while the second filter 152 is connected between the second bidirectional protection component 132 and the second sampling pin 12b of the sampling chip. This symmetrical structure improves the consistency of signals on the sampling paths of the first sampling pin 12a and the second sampling pin 12b, and enhances the anti-interference capability.

[0123] Both the first filter 151 and the second filter 152 can be at least one of, but not limited to, RC filters, low-pass filters, etc. The design parameters (such as resistance and capacitance values) of the first filter 151 and the second filter 152 can be optimized according to the operating frequency and noise characteristics of the sampling chip. By appropriately selecting the design parameters of the first filter 151 and the second filter 152, designers can effectively attenuate high-frequency noise components without affecting the dynamic response of the signal. Furthermore, the first filter 151 and the second filter 152 can also reduce voltage fluctuations caused by transient overvoltage events, thereby improving the stability and reliability of the input signal of the sampling chip.

[0124] In some implementations, when the tested battery cell assembly 20 generates a pulse current during charging and discharging, the presence of self-inductance in the copper contacts between the negative terminal of the tested battery cell assembly 20 and the shunt 11 may introduce transient voltage spikes across the shunt 11. When the pulse current causes a transient voltage spike, the first bidirectional protection component (such as a bidirectional TVS) absorbs the overvoltage energy, and the first filter 151 further smooths the voltage waveform, thereby suppressing high-frequency noise from entering the first sampling pin 12a of the sampling chip 12. Similarly, the second filter 152 smooths the voltage waveform and suppresses high-frequency noise, just like the first filter 151. Thus, the dual-path protection mechanism consisting of the first bidirectional protection component 131, the second bidirectional protection component 132, the first filter 151, and the second filter 152 significantly improves the robustness of the circuit.

[0125] Based on the above technical means, by setting a filter between the bidirectional protection component and the sampling pin, residual interference noise is further filtered out, improving the purity of the sampling signal, thereby improving the accuracy and stability of current measurement.

[0126] In some embodiments, such as Figure 8 As shown, the first filter 151 includes a first resistor R1 and a first capacitor C1. The first resistor R1 is connected in series between the first bidirectional protection component 131 and the first sampling pin 12a. One end of the first capacitor C1 is connected between the first resistor R1 and the first sampling pin 12a, and the other end of the first capacitor is connected to the reference ground pin 12c at the same potential.

[0127] The second filter 152 includes a second resistor R2 and a second capacitor C2. The second resistor R2 is connected in series between the second bidirectional protection component 132 and the second sampling pin 12b. One end of the second capacitor C2 is connected between the second resistor R2 and the second sampling pin 12b, and the other end of the second capacitor C2 is connected to the reference ground pin 12c at the same potential.

[0128] Here, both the first filter 151 and the second filter 152 are RC filters. RC filters have the advantages of simple structure, low cost, and ease of implementation. RC filters can be applied in high-frequency noise suppression scenarios. By reasonably selecting the parameters of the first resistor R1, the first capacitor C1, the second resistor R2, and the second capacitor C2, designers can effectively filter out noise within a specific frequency range, thereby improving the stability and accuracy of current sampling.

[0129] Based on the above technical means, by setting an RC filter between the bidirectional protection component and the sampling pin, high-frequency noise can be effectively filtered out, which can further enhance the current sampling circuit's ability to suppress interference and improve the overall reliability of the circuit.

[0130] The following example, using the current sampling circuit of the battery cell group in the battery management system, illustrates the application of the embodiments of this application in a real-world scenario.

[0131] In modern power electronic systems, especially in new energy vehicles and industrial power systems, AFE chips are widely used in battery management systems due to their high precision, high integration, and high reliability. Current sampling, a key function of battery management systems, is used to monitor the charging and discharging current of the battery pack in real time to ensure the safe and stable operation of the system.

[0132] In related technologies, current sampling circuits based on AFE chips typically use a shunt to measure current. One end of the shunt is connected to the negative terminal of the battery pack, and the other end is connected to the current sampling pin of the AFE chip. This architecture can operate stably under steady-state conditions, but under pulsed current conditions, especially when there is a large copper electrode at the negative terminal of the battery pack, it may cause a series of problems.

[0133] Under pulsed current conditions, the copper electrode may experience a significant voltage drop due to its self-inductance, leading to a potential mismatch between the shunt and the negative terminal of the battery pack. This potential mismatch may generate transient overvoltages on the current sampling pin of the AFE chip, causing the AFE chip's EOS (Effective Current Sample) to fail. Once EOS failure occurs, the AFE chip may be permanently damaged, severely impacting the reliability and safety of the entire battery management system.

[0134] To address this issue, some solutions in related technologies add a unidirectional TVS to the current sampling circuit to protect the current sampling pin of the AFE chip. A unidirectional TVS can absorb transient overvoltages to some extent, thus protecting the AFE chip from EOS (Effective Overvoltage). However, under certain operating conditions, such as BCI (Battery Integrated Circuit) conditions, the conduction state of the unidirectional TVS in the sampling paths corresponding to the two ends of the shunt may be inconsistent, leading to abrupt changes in current sampling. These abrupt changes reduce the accuracy of current sampling, further negatively impacting the control accuracy and reliability of the entire battery management system.

[0135] Based on this, this application proposes an improved current sampling circuit. This improved current sampling circuit significantly enhances the overall anti-interference capability and stability of the circuit by introducing components such as a bidirectional TVS, a common-mode inductor, and an RC filter.

[0136] Figure 9 A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Nine ,like Figure 9As shown, the current sampling circuit 10 includes: a shunt 11, an AFE chip 121, a bidirectional TVS (including TVS1 and TVS2), a common-mode inductor (including L1 and L2), and an RC filter (including R1, C1, R2, and C2). One end of the shunt 11 is connected to the negative terminal of the battery cell assembly 20 under test via a connector 30, thus connecting in series to the negative terminal circuit of the battery cell assembly 20. The AFE chip 121 connects to the positive terminal (Sense Resistor Positive, SRP) and negative terminal (Sample Resistor) of the sampling resistor. The Negative (SRN) pin is connected in parallel with shunt 11 to measure the charging and discharging current of the battery pack. TVS1 and TVS2 are connected in parallel across shunt 11 to absorb transient overvoltages in both positive and negative directions, thus providing more comprehensive protection for AFE chip 121 from EOS. The first common-mode inductor L1 and the second common-mode inductor L2 are connected in series between TVS1 and the shunt, and between TVS2 and the shunt, respectively, to effectively suppress common-mode interference and improve the anti-interference capability of the current sampling circuit. The first resistor R1 and the first capacitor C1 form a first RC filter, which is connected between the output of TVS1 and the SRN pin. The second resistor R2 and the second capacitor C2 form a second RC filter, which is connected between the output of TVS2 and the SRP pin. The first and second RC filters are used to further filter out high-frequency noise and improve the accuracy and stability of current sampling. The SRN pin and the SRP pin correspond to the first sampling pin 12a and the second sampling pin 12b in the aforementioned embodiment, respectively.

[0137] The current sampling circuit provided in the above-described embodiments of this application has at least the following technical effects:

[0138] 1) High reliability: By using bidirectional TVS, common-mode inductor and RC filter, the reliability of current sampling circuit can be effectively improved and the failure caused by transient overvoltage and common-mode interference can be reduced.

[0139] 2) High precision: By filtering out high-frequency noise and common-mode interference, the accuracy of current sampling can be improved, thereby improving the control precision of the entire battery management system.

[0140] 3) Easy to implement: The improved current sampling circuit provided in this application embodiment has a simple structure and is easy to implement. It can be easily modified and upgraded based on the existing circuit.

[0141] Furthermore, to further expand the application scenarios of this invention, ferrite beads can be used instead of common-mode inductors to achieve similar filtering and interference suppression effects as using common-mode inductors.

[0142] Figure 10A schematic diagram of the composition structure of a current sampling circuit provided in this application embodiment. Figure Ten ,like Figure 10 As shown, the current sampling circuit 10 includes: a shunt 11, an AFE chip 121, a bidirectional TVS (including TVS1 and TVS2), a first ferrite bead FB1, a second ferrite bead FB2, and an RC filter (including R1, C1, R2, and C2). The first ferrite bead FB1 and the second ferrite bead FB2 are connected in series between TVS1 and the shunt, and between TVS2 and the shunt, respectively, to effectively suppress common-mode interference and improve the anti-interference capability of the current sampling circuit. The ferrite beads present high impedance to high-frequency signals, and their impedance can effectively filter out high-frequency common-mode noise. Therefore, this current sampling circuit can also effectively suppress common-mode interference and transient overvoltage, thereby improving the anti-interference capability and reliability of the AFE chip.

[0143] In summary, the current sampling circuit provided in this application, by employing a bidirectional TVS, a common-mode inductor or ferrite bead, and an RC filter, can effectively improve the reliability of the current sampling circuit, reduce faults caused by transient overvoltage and common-mode interference, and possesses good practicality and promotional value. This improved current sampling circuit can be widely used in fields requiring high-precision current sampling, such as new energy vehicles and industrial power systems.

[0144] This application provides a battery management system, such as... Figure 11 As shown, the battery management system 40 includes the current sampling circuit 10 described in the above embodiments.

[0145] This application provides a battery device, such as... Figure 12 As shown, the battery device 50 includes the battery management system 40 described in the above embodiments.

[0146] Here, the battery device 50 may include, but is not limited to, a power battery device and / or an energy storage battery device, etc., and this application embodiment does not limit it.

[0147] This application provides an embodiment of an electrical device, such as... Figure 13 As shown, the electrical device 60 includes the battery device 50 described in the above embodiments.

[0148] Here, electrical equipment can be any electrical equipment, such as including but not limited to automobiles, airplanes, electric bicycles, electric motorcycles, electric boats, and / or ships.

[0149] It should be noted that the descriptions of the various embodiments above tend to emphasize the differences between them, while their similarities or commonalities can be referred to interchangeably. The descriptions of the electrical equipment embodiments above are similar to those of the battery device embodiments above, and have similar beneficial effects. For technical details not disclosed in the electrical equipment embodiments of this application, please refer to the descriptions of the battery device embodiments of this application for understanding.

[0150] It should be understood that in the description of this application, the reference to terms such as "in one embodiment," "in some embodiments," "in other embodiments," "yet another embodiment," "in some implementations," "in other implementations," or "exemplary," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the embodiments of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine the different embodiments or examples described in this application, as well as the features of the different embodiments or examples.

[0151] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0152] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and devices can be implemented in other ways. The apparatus and device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components may be combined, or integrated into another system, or some features may be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0153] The above are merely exemplary embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the protection scope of this application.

Claims

1. A current sampling circuit, characterized in that, include: The shunt is connected in series with the battery cell assembly under test. The sampling chip is connected in parallel with the shunt via a first sampling pin and a second sampling pin. It is used to collect the voltage across the shunt and determine the current flowing through the battery cell assembly under test based on the collected voltage. A bidirectional protection component includes a first bidirectional protection component and a second bidirectional protection component. The first bidirectional protection component is connected in parallel between the shunt and the first sampling pin to provide overvoltage protection for the first sampling pin in both positive and negative directions. The second bidirectional protection component is connected in parallel between the shunt and the second sampling pin to provide overvoltage protection for the second sampling pin in both positive and negative directions. The first filter assembly is connected in series between the bidirectional protection assembly and the splitter, and is used to filter the common-mode noise at both ends of the splitter.

2. The current sampling circuit according to claim 1, characterized in that, The reference ground pin of the sampling chip is connected to the negative terminal of the battery cell assembly under test, and the shunt is connected to the negative terminal of the battery cell assembly under test via a connector. The first end of the first bidirectional protection component is connected between the second end of the shunt and the first sampling pin, and the third end of the first bidirectional protection component is connected at the same potential to the reference ground pin. The fourth end of the second bidirectional protection component is connected between the fifth end of the shunt and the second sampling pin, and the sixth end of the second bidirectional protection component is connected at the same potential to the reference ground pin.

3. The current sampling circuit according to claim 1, characterized in that, The first bidirectional protection component includes a first bidirectional transient voltage suppressor, and the second bidirectional protection component includes a second bidirectional transient voltage suppressor.

4. The current sampling circuit according to claim 1, characterized in that, The first filter component includes a common-mode first inductor and a second inductor. The first inductor is connected in series between the first end of the first bidirectional protection component and the second end of the shunt, and the second inductor is connected in series between the fourth end of the second bidirectional protection component and the fifth end of the shunt.

5. The current sampling circuit according to claim 1, characterized in that, The first filter assembly includes a first magnetic bead and a second magnetic bead. The first magnetic bead is connected in series between a first end of the first bidirectional protection assembly and a second end of the splitter, and the second magnetic bead is connected in series between a fourth end of the second bidirectional protection assembly and a fifth end of the splitter.

6. The current sampling circuit according to any one of claims 1 to 5, characterized in that, Also includes: The second filtering component includes a first filter and a second filter. The first filter is disposed between the first bidirectional protection component and the first sampling pin, and the second filter is disposed between the second bidirectional protection component and the second sampling pin.

7. The current sampling circuit according to claim 6, characterized in that, The first filter includes a first resistor and a first capacitor. The first resistor is connected in series between the first bidirectional protection component and the first sampling pin. One end of the first capacitor is connected between the first resistor and the first sampling pin, and the other end of the first capacitor is connected at the same potential to the reference ground pin of the sampling chip. The second filter includes a second resistor and a second capacitor. The second resistor is connected in series between the second bidirectional protection component and the second sampling pin. One end of the second capacitor is connected between the second resistor and the second sampling pin, and the other end of the second capacitor is connected at the same potential to the reference ground pin.

8. A battery management system, characterized in that, The battery management system includes a current sampling circuit as described in any one of claims 1 to 7.

9. A battery device, characterized in that, The battery device includes the battery management system as described in claim 8.

10. An electrical appliance, characterized in that, The electrical equipment includes the battery device as described in claim 9.

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