Current precision improving circuit of battery management system

Abstract

The utility model provides a current precision improving circuit of a battery management system. The current precision improving circuit comprises a detection circuit, a battery cell group, a precision conversion circuit and an MCU processing circuit. The detection circuit is arranged in a charging and discharging loop of the battery management system; firstly, a detection circuit measures an initial voltage value by connecting positive and negative electrodes of a battery cell group, and is connected in series with a discharge and charge control module; the precision conversion circuit then processes the initial voltage value to obtain a high-precision voltage value, and finally the MCU processing circuit converts the high-precision voltage value into a high-precision current value and displays the high-precision current value through an upper computer. According to the battery management system, high-precision voltage and current detection is realized through cooperative work of the detection circuit, the precision conversion circuit and the MCU processing circuit, so that the use efficiency and the safety of the battery are effectively improved. Through the process, the system can accurately monitor the current change, the stability and safety of the battery in the charging and discharging process are ensured, and the reliability and performance of the whole battery system are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery management system technical field especially relates to a current precision improvement circuit of battery management system. BACKGROUND

[0002] With the popularity of electric vehicles, portable electronic devices and renewable energy storage applications, the current precision of the battery management system (BMS) is particularly important. The accuracy of current measurement directly affects the charging and discharging process of the battery, and thus affects its safety, performance and service life. If the current measurement precision is insufficient, it may lead to inaccurate monitoring, and the real state of the battery cannot be identified in time, thereby causing overcharging or overdischarging, increasing the risk of battery swelling or fire. In addition, inaccurate current will lead to unbalanced charging of the battery pack, causing capacity loss and energy efficiency decline, and affecting the estimation of the remaining capacity (SOC) and the health state (SOH), increasing the difficulty of fault diagnosis.

[0003] Therefore, improving the current measurement precision in the BMS is a key technical challenge to improve the efficiency of battery charging and discharging, prolong the service life and ensure safe operation. SUMMARY

[0004] Therefore, the utility model embodiment provides a current precision improvement circuit of battery management system to improve the current measurement precision in the BMS.

[0005] To achieve the above-mentioned purpose, the utility model embodiment provides the following technical scheme:

[0006] The utility model discloses a kind of current precision improvement circuits of battery management system, and the circuit includes: detection circuit, battery cell group, precision conversion circuit and MCU processing circuit;

[0007] The detection circuit is arranged in the charge-discharge loop of the battery management system;The positive pole of the battery cell group is connected to the external load by screw column;

[0008] The first end of the detection circuit is connected to the positive pole of the battery cell group, and the second end of the detection circuit is connected to the negative pole of the battery cell group;The detection circuit is connected in series with the discharge control module and the charge control module of the battery management system;One end of the charge control module is connected to the external load;

[0009] The third end of the detection circuit is connected to the discharge control module, and the fourth end of the detection circuit is connected to the charge control module;

[0010] An output end of the detection circuit is connected to an input end of the precision conversion circuit;

[0011] An output end of the precision conversion circuit is connected to a first input end of the MCU processing circuit; a second input end of the MCU processing circuit is connected to a positive electrode of the battery cell group through a DC-DC converter;

[0012] The detection circuit is configured to detect a voltage division value of itself to obtain an initial voltage value.

[0013] The precision conversion circuit is configured to process the initial voltage value to obtain a high-precision voltage value.

[0014] The MCU processing circuit is configured to convert the high-precision voltage value into a high-precision current value and display the high-precision current value through an upper computer.

[0015] Preferably, the detection circuit comprises a high-precision sampling resistor and a battery management chip.

[0016] One end of the high-precision sampling resistor is connected to a negative electrode of the battery cell group; the other end of the high-precision sampling resistor is connected to the discharge control module.

[0017] An ISP pin and an ISM pin of the battery management chip are respectively connected to two ends of the high-precision sampling resistor.

[0018] An IMON pin of the battery management chip is connected to the precision conversion circuit; an input end of the battery management chip is connected to a positive electrode of the battery cell group.

[0019] A DFET pin of the battery management chip is connected to the discharge control module; a CFET pin of the battery management chip is connected to the charge control module.

[0020] The battery management chip is configured to detect a voltage division value between two ends of the high-precision sampling resistor through the ISP pin and the ISM pin, determine the initial voltage value based on a threshold voltage and the voltage division value, and send the initial voltage value to the precision conversion circuit through the IMON pin.

[0021] Preferably, the precision conversion circuit comprises an analog-to-digital converter.

[0022] An input end of the analog-to-digital converter is connected to the detection circuit; an output end of the analog-to-digital converter is connected to the MCU processing circuit.

[0023] The analog-to-digital converter is configured to process the initial voltage value through an internal delta-sigma A / D converter and a reference voltage to obtain the high-precision voltage value, and output the high-precision voltage value to the MCU processing circuit.

[0024] Preferably, the MCU processing circuit comprises a single-chip microcomputer.

[0025] The first input end of the single-chip microcomputer is connected with the positive pole of the battery cell group through the DC-DC converter; and the second input end of the single-chip microcomputer is connected with the precision conversion circuit.

[0026] The single-chip microcomputer is configured to convert the high-precision voltage value into a high-precision current value, and transmit the high-precision current value to the upper computer through a communication circuit for display; and the single-chip microcomputer is further configured to monitor the temperature of each battery in the battery cell group in real time.

[0027] Preferably, the battery cell group comprises a plurality of secondary batteries.

[0028] Preferably, the secondary battery is a lithium ion battery or a sodium ion battery or a solid-state battery.

[0029] Preferably, the material of the high-precision sampling resistor is a can alloy.

[0030] Preferably, the battery management chip is a high-precision operational amplifier with an editable amplification factor.

[0031] Preferably, the discharge control module comprises a first MOS drive and a discharge MOS; and the charge control module comprises a second MOS drive and a charge MOS.

[0032] One end of the first MOS drive is connected with a DFET pin of the battery management chip; and the other end of the first MOS drive is connected with a gate of the discharge MOS.

[0033] A source of the discharge MOS is connected with one end of the high-precision sampling resistor; and a drain of the discharge MOS is connected with a drain of the charge MOS.

[0034] One end of the second MOS drive is connected with a CFET pin of the battery management chip; the other end of the second MOS drive is connected with a gate of the charge MOS; and a source of the charge MOS is connected with a load.

[0035] Preferably, the analog-to-digital converter is a continuous self-calibration analog-to-digital converter with differential input and 16-bit resolution.

[0036] The current precision improving circuit of the battery management system provided by the embodiment of the utility model, including detection circuit, electric core group, precision conversion circuit and MCU processing circuit, detection circuit sets up in the charge-discharge loop of battery management system, the positive pole of electric core group is connected external load through screw column, the first end of detection circuit connects electric core group positive pole, the second end connects negative pole, and is connected with discharge control module and charge control module in series. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will be briefly introduced the drawing needed to be used in the embodiment or prior art description, obviously, the drawing in the following description is only the embodiment of the utility model, for the ordinary skilled person in the art, under the premise of not paying the creative labor, can also obtain other drawings according to the provided drawing.

[0038] Figure 1 The first schematic diagram of the current precision improving circuit of the battery management system provided by the embodiment of the utility model is provided;

[0039] Figure 2 The second schematic diagram of the current precision improving circuit of the battery management system provided by the embodiment of the utility model is provided;

[0040] Figure 3 The partial schematic diagram of detection circuit 1 provided by the embodiment of the utility model is provided;

[0041] Figure 4 The detailed schematic diagram of battery management chip 12 provided by the embodiment of the utility model is provided;

[0042] Figure 5 The third schematic diagram of the current precision improving circuit of the battery management system provided by the embodiment of the utility model is provided;

[0043] Figure 6 The detailed schematic diagram of analog-digital converter 31 provided by the embodiment of the utility model is provided;

[0044] Figure 7A fourth schematic view of a current precision improving circuit of a battery management system is provided in the embodiments of the present application.

[0045] Figure 8 A part of detailed schematic view of MCU processing circuit 4 is provided in the embodiments of the present application. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0047] In the present application, the term "comprising", "containing" or any other variant thereof is intended to cover the non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the sentence "including a" does not exclude the existence of other identical elements in the process, method, article or equipment including the element.

[0048] As known from the background, the current precision of the battery management system directly affects the charging and discharging process of the battery, and further affects the safety, performance and service life thereof. At present, the battery BMS current precision cannot meet the use requirements, resulting in problems such as inaccurate charging and discharging process, overcharging and overdischarging, battery pack capacity loss, inaccurate battery state estimation, etc. If the measured current precision is insufficient, it may lead to inaccurate monitoring, and the real state of the battery cannot be identified in time, thereby causing overcharging or overdischarging, increasing the risk of battery swelling or fire. In addition, inaccurate current will lead to unbalanced charging of the battery pack, causing capacity loss and energy efficiency decline, and affecting the estimation of remaining capacity and health state, increasing the difficulty of fault diagnosis.

[0049] Therefore, the battery management system current precision improving circuit provided by the embodiment of the utility model can realize high-precision voltage and current detection through the cooperative work of the detection circuit, the precision conversion circuit and the MCU processing circuit, thereby effectively improving the use efficiency and safety of the battery.

[0050] Referring to Figure 1 , a first schematic diagram of a battery management system current precision improving circuit is shown.

[0051] The battery management system current precision improving circuit comprises a detection circuit 1, a battery cell group 2, a precision conversion circuit 3 and a MCU processing circuit 4.

[0052] Specifically, the detection circuit 1 is arranged in the charge-discharge circuit of the battery management system. The first end of the detection circuit 1 is connected to the positive pole of the battery cell group 2, and the second end of the detection circuit 1 is connected to the negative pole of the battery cell group 2. The positive pole of the battery cell group 2 is connected to an external load through a screw column.

[0053] It should be noted that the battery cell group 2 comprises a plurality of secondary batteries. For example, 8 to 16 battery cells are connected in series; the positive pole of the battery cell group 2 is B+, i.e. Battery+; and the negative pole of the battery cell group 2 is B-, i.e. Battery-. Figure 1 Figure 1

[0054] The secondary battery is specifically a lithium ion battery or a sodium ion battery or a solid-state battery. For example, the battery cell group 2 comprises a plurality of lithium ion batteries, or the battery cell group 2 comprises a plurality of sodium ion batteries, or the battery cell group 2 comprises a plurality of solid-state batteries. Since these types of batteries are prone to overcharging, over-discharging or explosion, etc., the battery cell group 2 must be used in combination with the battery management system.

[0055] It can be understood that the detection circuit 1 detects the voltage value of the high-precision resistor in the charge-discharge circuit (i.e. the voltage value of the high-precision resistor 11 contained in the detection circuit 1 shown in the following Figure 2 ).

[0056] ​​It should be noted that the positive electrode of the battery cell group 2 is connected to the external load using a screw column, which can improve the connection stability and overall efficiency of the battery cell group 2, and simplify the maintenance process.

[0057] Specifically, the detection circuit 1 is connected in series with the discharge control module 5 and the charging control module 6 in the battery management system. The charging control module 6 is connected to one end of the external load. The third end of the detection circuit 1 is connected to the discharge control module 5, and the fourth end of the detection circuit 1 is connected to the charging control module 6.

[0058] It should be noted that in a multi-cell system, the discharge control module 5 and the charging control module 6 can realize the charging and discharging of each battery in the battery cell group 2, improve the overall performance and service life of the battery group, and effectively improve the safety, efficiency and intelligent degree of the battery management system.

[0059] It can be understood that the detection circuit 1 is connected to the discharge control module 5 and the charging control module 6 in the battery management system, respectively, and by detecting the charging and discharging current, the MCU processing circuit 4 can timely control the conduction and turn-off of the MOS of the discharge control module 5 and the charging control module 6, to prevent safety risks such as overcharging, overdischarging and short circuit. In addition, controlling the charging and discharging MOS can effectively manage the temperature of the battery cell group 2, reduce heat generation, and prevent damage caused by overheating.

[0060] Specifically, the output end of the detection circuit 1 is connected to the input end of the precision conversion circuit 3.

[0061] It should be noted that the detection circuit 1 detects the initial voltage value by detecting the voltage value of itself, and transmits the initial voltage value to the input end of the precision conversion circuit 3 through the output end.

[0062] It can be understood that the detection circuit 1 includes a plurality of resistors and battery management chips, and the specific structure of the detection circuit 1 is described in detail in the following embodiment of the utility model Figure 2 .

[0063] Specifically, the output end of the precision conversion circuit 3 is connected to the first input end of the MCU processing circuit 4. The second input end of the MCU processing circuit 4 is connected to the positive electrode of the battery cell group 2 through a DC-DC converter.

[0064] It can be understood that the MCU processing circuit 4 is connected to the battery cell group 2 through a DC-DC converter (DC-DC converter). The DC-DC converter can adjust the voltage of the battery cell group 2 to the working voltage required by the MCU processing circuit 4, to ensure its stable operation. Secondly, efficient conversion can reduce energy loss, prolong the use time of the battery, and is especially suitable for battery-powered devices. In addition, the DC-DC converter has good noise suppression capability, can provide more stable power supply, and improves the anti-interference performance of the system.

[0065] It should be noted that the precision conversion circuit 3 improves the precision of the initial voltage value after receiving the initial voltage value, and obtains a high-precision voltage value. The precision conversion circuit 3 transmits the high-precision voltage value to the first input end of the MCU processing circuit 4 through the output end.

[0066] It can be understood that after the MCU processing circuit 4 receives the high-precision voltage value, the high-precision voltage value is converted into a high-precision current value, and the high-precision current value is displayed through the host computer.

[0067] It should be noted that the precision conversion circuit 3 includes an analog-to-digital converter, and the specific structure of the precision conversion circuit 3 is described in detail in the following embodiments of the utility model Figure 5 The MCU processing circuit 4 includes a single-chip microcomputer, and the specific structure of the MCU processing circuit 4 is described in detail in the following embodiments of the utility model Figure 7 .

[0068] In the embodiments of the utility model, through the cooperative work of the detection circuit, the precision conversion circuit and the MCU processing circuit, the high-precision voltage and current detection are realized, so that the use efficiency and safety of the battery are effectively improved. First, the detection circuit measures the initial voltage value of itself by connecting the positive and negative poles of the battery cell group, and is connected in series with the discharge and charge control module. The precision conversion circuit then processes the initial voltage value to obtain a high-precision voltage value, and finally the MCU processing circuit converts the high-precision voltage value into a high-precision current value and displays the high-precision current value through the host computer. Through this process, the system can accurately monitor the current change, ensure the stability and safety during the battery charging and discharging process, and improve the reliability and performance of the overall battery system.

[0069] The specific structure of the detection circuit 1 involved in the above embodiments of the utility model Figure 1 is described in detail in the following Figure 2 , which shows a second schematic diagram of the current precision improvement circuit of the battery management system according to an embodiment of the utility model. The detection circuit 1 comprises: a high-precision sampling resistor 11 and a battery management chip 12.

[0070] Specifically, one end of the high-precision sampling resistor 11 is connected to the negative pole of the battery cell group 2; the other end of the high-precision sampling resistor 11 is connected to the discharge control module 5.

[0071] In specific embodiments, the detection circuit 1 comprises a plurality of high-precision sampling resistors 11, and the high-precision sampling resistors 11 are connected in parallel. As shown in Figure 3 , the high-precision sampling resistor 11 can be a 2mΩ resistor.

[0072] In specific applications, the high-precision sampling resistor 11 can be a high-precision sampling resistor with high power and low resistance. The material of the high-precision sampling resistor 11 is an encapsulating alloy material.

[0073] Specifically, the ISP pin and the ISM pin of the battery management chip 12 are connected to the two ends of the high-precision sampling resistor 11, for example Figure 3 as shown.

[0074] It should be noted that the battery management chip 12 is a high-precision operational amplifier with an editable amplification factor. As shown in the detailed schematic diagram of the battery management chip 12 Figure 4 , the battery management chip 12 is an ML5238 type operational amplifier.

[0075] It can be understood that the battery management chip 12 detects the voltage drop between the two ends of the high-precision sampling resistor 11 through the ISP pin and the ISM pin, and specifically determines the initial voltage value according to the threshold voltage and the voltage drop.

[0076] It should be noted that the threshold voltage can be set, for example, the threshold voltage is 1.0V(typ).

[0077] Since when the battery in the battery cell group 2 is charging, the voltage difference between the ISP pin and the ISM pin is less than 1V. This indicates that the current is flowing into the battery at this time, and the voltage difference in the charging state is low, which may mean that the battery is in a low charging state. When the battery in the battery cell group 2 is discharging, the voltage difference between the ISP pin and the ISM pin is greater than 1V. This indicates that the current is flowing out of the battery at this time, and the voltage difference in the discharging state is high, indicating that the battery is providing power to the load; based on this, the battery management chip 12 determines the initial voltage value.

[0078] Specifically, the IMON pin of the battery management chip 12 is connected to the precision conversion circuit 3, and the input end of the battery management chip 12 is connected to the positive electrode of the battery cell group 2.

[0079] It can be understood that the battery management chip 12 transmits the initial voltage value to the precision conversion circuit 3 through the IMON pin.

[0080] It should be noted that the input end of the battery management chip 12 is connected to the positive electrode of the battery cell group 2. The battery cell group 2 supplies power to the battery management chip 12.

[0081] Specifically, the DFET pin of the battery management chip 12 is connected to the discharge control module 5, and the CFET pin of the battery management chip 12 is connected to the charging control module 6, as shown in Figure 3 .

[0082] It can be understood that the battery management chip 12 controls discharging and charging through the DFET pin and the CFET pin respectively, can independently manage the charging and discharging process of the battery, and realizes a more accurate protection mechanism, such as timely cutting off the current during discharging to prevent over-discharging, ensuring the safety of the battery and improving the flexibility and efficiency of the system.

[0083] Specifically, the discharging control module 5 includes a first MOS drive 51 and a discharging MOS 52; and the charging control module 6 includes a second MOS drive 61 and a charging MOS 62.

[0084] In some specific embodiments, the number of the discharging MOS 52 and the charging MOS 62 is 12 respectively.

[0085] Among them, the discharging MOS is a discharging field effect transistor; and the charging MOS is a charging field effect transistor.

[0086] Specifically, one end of the first MOS drive 51 is connected to the DFET pin of the battery management chip 12; and the other end of the first MOS drive 51 is connected to the gate of the discharging MOS 52.

[0087] Specifically, one end of the discharging MOS 52 is connected to one end of the high-precision sampling resistor 11; and the drain of the discharging MOS 52 is connected to the drain of the charging MOS 62.

[0088] Specifically, one end of the second MOS drive 61 is connected to the CFET pin of the battery management chip 12; the other end of the second MOS drive 61 is connected to the gate of the charging MOS 62; and the source of the charging MOS 62 is connected to the load.

[0089] In some embodiments, the battery management chip 12 can also be used to correct the current signal to ensure that a zero current reference value can be accurately output when there is no current flowing. Specifically, this process involves the following aspects:

[0090] The battery management chip 12 is used to sample the current of the high-precision sampling resistor 11, and will output a voltage signal proportional to the current. In actual application, zero drift may occur due to temperature changes, device characteristics differences, etc., resulting in a signal output of a biased value instead of zero when there is no current flowing. In order to eliminate this drift, a reference voltage (usually the ideal output voltage when there is no current flowing) is set, and the output of the battery management chip 12 is corrected. By correcting the zero current reference voltage, the actual charging and discharging current of the battery can be more accurately measured, thereby improving the monitoring accuracy and reliability.

[0091] In the embodiment of the utility model, the initial voltage value is determined based on the threshold voltage and the voltage division value by detecting the voltage division value at both ends of the high-precision sampling resistor. The precision conversion circuit then processes the initial voltage value to obtain a high-precision voltage value. Finally, the MCU processing circuit converts the high-precision voltage value into a high-precision current value and displays it through the upper computer. Through this process, the system can accurately monitor the current change, ensure the stability and safety during the battery charging and discharging process, and improve the reliability and performance of the overall battery system.

[0092] The specific structure of the precision conversion circuit 3 involved in the above embodiment of the utility model Figure 1 is shown in Figure 5 , which shows a third schematic diagram of the current precision improvement circuit of the battery management system according to the embodiment of the utility model. The precision conversion circuit 3 comprises an analog-to-digital converter 31.

[0093] It can be understood that the input end of the analog-to-digital converter 31 is connected to the detection circuit 1, and the output end of the analog-to-digital converter 31 is connected to the MCU processing circuit 4.

[0094] Specifically, as shown in Figure 5 , the input end of the analog-to-digital converter 31 is connected to the IMON pin of the battery management chip 12 in the detection circuit 1.

[0095] It should be noted that the analog-to-digital converter 31 is a continuous self-calibration analog-to-digital converter with differential input and 16-bit resolution.

[0096] It can be understood that the analog-to-digital converter 31 processes the initial voltage value through an internal delta-sigma A / D converter and a reference voltage to obtain a high-precision voltage value and outputs it to the MCU processing circuit 4.

[0097] For example Figure 6 , as shown in the detailed schematic diagram of the analog-to-digital converter 31, the analog-to-digital converter 31 is U7 as shown in Figure 6 , which measures the voltage difference between the positive and negative analog inputs (i.e. the voltage difference between pin 1 and pin 6 of U7 as shown in Figure 6 , that is, the voltage difference between the initial voltage value output by the IMON pin of the battery management chip 12 and the voltage value to ground) through the internal modulator, compares it with the reference voltage, improves the voltage precision, obtains a high-precision voltage value, and outputs it to the MCU processing circuit 4.

[0098] It can be understood that the U7 self-calibration analog-digital converter can automatically adjust the internal parameters (such as the reference voltage) to improve the conversion accuracy, reduce the system error, and provide more accurate voltage readings. In addition, the U7 self-calibration analog-digital converter can be flexibly configured according to application requirements to meet the accuracy requirements of different voltage measurements. Based on this, the use of the U7 self-calibration analog-digital converter can significantly improve the accuracy of voltage measurement and the stability of the system.

[0099] In the embodiment of the utility model, the initial voltage value is improved in precision by the self-calibration analog-digital converter to obtain a high-precision voltage value, which helps to reduce system error, provide more accurate voltage readings, and significantly improve the accuracy of voltage measurement and the stability of the system.

[0100] The above embodiment of the utility model Figure 1 relates to the specific structure of the MCU processing circuit 4, which is described in detail in the following Figure 7 , which shows a fourth schematic diagram of a current precision improvement circuit of a battery management system according to an embodiment of the utility model. The MCU processing circuit 4 comprises: a single-chip microcomputer 41.

[0101] It can be understood that the first input end of the single-chip microcomputer 41 is connected to the positive electrode of the battery cell group 2 through a DC-DC converter; and the second input end of the single-chip microcomputer 41 is connected to the precision conversion circuit 3.

[0102] Specifically, the second input end of the single-chip microcomputer 41 is connected to the analog-digital converter 31. The single-chip microcomputer 41 is used to convert the high-precision voltage value transmitted by the analog-digital converter 31 into a high-precision current value, and transmit the high-precision current value to the upper computer through the communication circuit (485) for display.

[0103] For example Figure 8 As shown in the partial detailed schematic diagram of the MCU processing circuit 4, the PB14 pin and the PB15 pin of the single-chip microcomputer 41 are connected to the pin 3 and the pin 4 of the U7 self-calibration analog-digital converter to receive the high-precision voltage value sent by the U7 self-calibration analog-digital converter.

[0104] In some specific embodiments, the single-chip microcomputer 41 is further used to monitor the temperature of each battery in the battery cell group 2 in real time.

[0105] In the embodiment of the utility model, the high-precision voltage value is converted into a high-precision current value by the single-chip microcomputer, and then displayed by the upper computer, which helps to improve the use efficiency and safety of the battery, prolong the service life of the battery, and thus improve the reliability and performance of the entire battery system, and ensure the overall performance and service life of the battery cell group.

[0106] The various embodiments described in this specification are described in progressive order, and each embodiment can be understood in relation to the others. Each embodiment is directed to the differences between that embodiment and the others. In particular, the system or system embodiments are described with less detail than the method embodiments, as they are substantially similar to the method embodiments. The system and system embodiments described above are merely illustrative, and the units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located at one place or distributed over multiple network units. Some or all of the modules can be selected to achieve the purposes of the embodiments according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0107] The skilled person will further appreciate that the elements of an example described in relation to the embodiments disclosed herein can be implemented in electronic hardware, computer software, or combinations of both. These elements and algorithms described in the above description with reference to an example are implemented as, what in technology terms, is known as "functions". Whether these functions are implemented as hardware or software depends on the particular applications and design constraints. The skilled person can implement the described functions in varying ways for each particular application, but such implementation does not bring a contribution to the scope of the present invention.

[0108] The above description of disclosed embodiments enables a person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A current accuracy improvement circuit of a battery management system, characterized by, The circuit comprises a detection circuit, a battery cell group, a precision conversion circuit and an MCU processing circuit; The detection circuit is arranged in a charge-discharge loop of a battery management system; a positive electrode of the battery cell group is connected to an external load through a screw column; A first end of the detection circuit is connected to a positive electrode of the battery cell group, and a second end of the detection circuit is connected to a negative electrode of the battery cell group; the detection circuit is connected in series with a discharge control module and a charge control module of the battery management system; one end of the charge control module is connected to the external load; A third end of the detection circuit is connected to the discharge control module, and a fourth end of the detection circuit is connected to the charge control module; An output end of the detection circuit is connected to an input end of the precision conversion circuit; An output end of the precision conversion circuit is connected to a first input end of the MCU processing circuit; a second input end of the MCU processing circuit is connected to a positive electrode of the battery cell group through a DC-DC converter; The detection circuit is configured to detect a voltage division value of itself to obtain an initial voltage value; The precision conversion circuit is configured to process the initial voltage value to obtain a high-precision voltage value; The MCU processing circuit is configured to convert the high-precision voltage value into a high-precision current value and display the high-precision current value on a host computer.

2. The circuit of claim 1, wherein, The detection circuit comprises a high-precision sampling resistor and a battery management chip; One end of the high-precision sampling resistor is connected to a negative electrode of the battery cell group; the other end of the high-precision sampling resistor is connected to the discharge control module; ISP and ISM pins of the battery management chip are respectively connected to two ends of the high-precision sampling resistor; An IMON pin of the battery management chip is connected to the precision conversion circuit, and an input end of the battery management chip is connected to a positive electrode of the battery cell group; A DFET pin of the battery management chip is connected to the discharge control module, and a CFET pin of the battery management chip is connected to the charge control module; The battery management chip is configured to detect a voltage division value between two ends of the high-precision sampling resistor through the ISP and ISM pins, determine the initial voltage value based on a threshold voltage and the voltage division value, and send the initial voltage value to the precision conversion circuit through the IMON pin.

3. The circuit of claim 1, wherein, The precision conversion circuit comprises an analog-to-digital converter; An input end of the analog-to-digital converter is connected to the detection circuit, and an output end of the analog-to-digital converter is connected to the MCU processing circuit; The analog-to-digital converter is configured to process the initial voltage value through an internal delta-sigma A / D converter and a reference voltage to obtain the high-precision voltage value and output the high-precision voltage value to the MCU processing circuit.

4. The circuit of claim 1, wherein, The MCU processing circuit comprises a single-chip microcomputer; A first input end of the single-chip microcomputer is connected to a positive electrode of the battery cell group through the DC-DC converter; a second input end of the single-chip microcomputer is connected to the precision conversion circuit; The single-chip microcomputer is configured to convert the high-precision voltage value into the high-precision current value and transmit the high-precision current value to the host computer through a communication circuit for display; the single-chip microcomputer is also configured to monitor temperatures of each battery in the battery cell group in real time.

5. The circuit of claim 1, wherein, The battery cell group comprises a plurality of secondary batteries.

6. The circuit of claim 5, wherein, The secondary batteries are lithium ion batteries or sodium ion batteries or solid-state batteries.

7. The circuit of claim 2, wherein, The material of the high-precision sampling resistor is a sealing alloy.

8. The circuit of claim 2, wherein, The battery management chip is a high-precision operational amplifier with an editable magnification.

9. The circuit of claim 2, wherein, The discharge control module comprises a first MOS drive and a discharge MOS; the charge control module comprises a second MOS drive and a charge MOS; One end of the first MOS drive is connected to a DFET pin of the battery management chip; the other end of the first MOS drive is connected to a gate of the discharge MOS; A source of the discharge MOS is connected to one end of the high-precision sampling resistor; a drain of the discharge MOS is connected to a drain of the charge MOS; One end of the second MOS drive is connected to a CFET pin of the battery management chip; the other end of the second MOS drive is connected to a gate of the charge MOS; a source of the charge MOS is connected to a load.

10. The circuit of claim 3, wherein, The analog-to-digital converter is a continuous self-calibration analog-to-digital converter with differential input and 16-bit resolution.

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