Current collection self-checking circuit and method based on bms applications

Abstract

The application discloses a current collection self-checking circuit and method based on BMS application, the circuit comprising a battery unit, a positive electrode port, a negative electrode port, a current detection resistor RS, a switching circuit, a control circuit and a collection circuit, the positive electrode of the battery unit is electrically connected with the positive electrode port, the negative electrode is electrically connected with the negative electrode port through the current detection resistor RS, the switching circuit is arranged in parallel between the positive electrode port and the negative electrode port, the control circuit is used for collecting the battery voltage Vbat of the battery unit and is used for turning on the switching circuit, so that the battery unit, the switching circuit and the current detection resistor RS jointly constitute a collection loop, the collection circuit is used for collecting the current detection voltage Vrs flowing through the current detection resistor RS, and the control circuit is used for detecting the current collection accuracy of the collection circuit according to the difference between the current detection voltage Vrs and the theoretical current detection voltage VO; the detection of the defective product collection circuit does not need manual intervention, the missed detection of the defective product collection circuit caused by human intervention is avoided, and the safety hidden danger caused by the missed detection of the defective product collection circuit is effectively prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of current acquisition self-verification, and in particular to a current acquisition self-verification circuit and method based on BMS application. Background Art

[0002] In BMS applications, current acquisition accuracy significantly impacts the system, directly affecting its ability to correct SOX (lithium-ion battery management system) errors. Existing BMS-based current acquisition accuracy calibration solutions typically involve an on-line calibration process, relying on manual or machine input of multiple-point current correction values.

[0003] However, when defective products appear but are missed, they flow into the market, which may bring major quality risks, such as the failure of the BMS due to large deviations in current collection accuracy.

[0004] In addition, the existing BMS-based current acquisition accuracy calibration solution cannot automatically identify faults when the current detection resistor network system is short-circuited or open-circuited, and there is a risk that defective products will flow into the market. Summary of the Invention

[0005] The purpose of the present invention is to provide a current acquisition self-checking circuit and method based on BMS application, in which the detection process of the defective acquisition circuit does not require human intervention, avoiding the missed detection of the defective acquisition circuit due to human intervention, and effectively preventing the safety hazards caused by the missed detection of the defective acquisition circuit.

[0006] In order to achieve the above-mentioned objectives, the present invention discloses a current acquisition self-verification circuit based on BMS application, which includes a battery cell, a positive port, a negative port, a current sensing resistor RS, a switching circuit, a control circuit and an acquisition circuit. The positive pole of the battery cell is electrically connected to the positive port, and the negative pole is electrically connected to the negative port through the current sensing resistor RS. The switching circuit is arranged in parallel between the positive port and the negative port. The control circuit is used to acquire the battery voltage Vbat of the battery cell and to turn on the switching circuit so that the battery cell, the switching circuit and the current sensing resistor RS together constitute an acquisition loop. The acquisition circuit is used to acquire the current sensing voltage Vrs flowing through the current sensing resistor RS. The control circuit is used to detect the current acquisition accuracy of the acquisition circuit based on the difference between the current sensing voltage Vrs and the theoretical current sensing voltage VO.

[0007] Preferably, the switching circuit includes a first resistor R1 and a switching unit, one end of the switching unit is electrically connected between the positive electrode and the positive port of the battery cell through the first resistor R1, and the other end is electrically connected between the negative port and the current sensing resistor RS.

[0008] Preferably, the control circuit includes a control unit, and the control unit includes a first acquisition terminal and a control terminal, the first acquisition terminal is used to acquire the battery voltage Vbat of the battery unit, and the control terminal is used to control the on and off of the switch unit.

[0009] Preferably, the control circuit further includes a fourth resistor R4 and a fifth resistor R5, one end of the fourth resistor R4 is electrically connected between the positive electrode of the battery cell and the switching circuit, and the other end is grounded through the fifth resistor R5, and the first acquisition end is electrically connected between the fourth resistor R4 and the fifth resistor R5.

[0010] Preferably, the switch unit is a MOS tube, the drain of the switch unit is electrically connected between the positive electrode and the positive port of the battery unit through the first resistor R1, the source is electrically connected between the negative port and the current sensing resistor RS, and the gate is electrically connected to the control end.

[0011] Preferably, the acquisition circuit includes an acquisition unit, the acquisition unit includes an acquisition terminal group and a first communication terminal, the control unit also includes a second communication terminal, the acquisition terminal group is used to acquire the current sensing voltage Vrs of the current sensing resistor RS, and the first communication terminal is electrically connected to the second communication terminal.

[0012] Preferably, the acquisition circuit further includes a second resistor R2 and a third resistor R3, the acquisition terminal group includes a negative acquisition terminal and a positive acquisition terminal, the negative acquisition terminal is electrically connected between the negative electrode of the battery cell and the current sensing resistor RS through the second resistor R2, and the positive acquisition terminal is electrically connected between the current sensing resistor RS and the switch unit through the third resistor R3.

[0013] Preferably, the acquisition circuit further includes a sixth resistor R6 , one end of the sixth resistor R6 is electrically connected between the second resistor R2 and the current sensing resistor RS, and the other end of the sixth resistor R6 is electrically connected between the third resistor R3 and the current sensing resistor RS.

[0014] Preferably, the current acquisition self-checking circuit based on BMS application further includes a DC-DC conversion unit, the input end of the DC-DC conversion unit is electrically connected to the positive electrode of the battery unit, and the output end is used to electrically connect to an external device.

[0015] Accordingly, the present invention further discloses a current acquisition self-verification method based on BMS application, which is applied to the current acquisition self-verification circuit based on BMS application as described above. The current acquisition self-verification method based on BMS application includes the following steps:

[0016] S1, collecting the battery voltage Vbat of the battery unit;

[0017] S2, turn on the switch circuit so that the battery unit, the switch circuit and the current-sense resistor RS together form a collection loop;

[0018] S3, collecting the current-sense voltage Vrs flowing through the current-sense resistor RS;

[0019] S4, detecting the current acquisition accuracy of the acquisition circuit according to the difference between the current detection voltage Vrs and the theoretical current detection voltage V0;

[0020] S5. If the current acquisition accuracy of the acquisition circuit does not meet the preset acquisition accuracy standard, the current acquisition circuit is marked as a defective acquisition circuit and a defect alarm is issued;

[0021] S6. If the current acquisition accuracy of the acquisition circuit meets the preset acquisition accuracy standard, then mark the current acquisition circuit as a good acquisition circuit;

[0022] S7, calculating the current sense current Irs of the current sense resistor RS corresponding to the good product acquisition circuit according to the battery voltage Vbat;

[0023] S8. According to the current sensing current Irs of the current sensing resistor RS corresponding to the good product acquisition circuit, calibrate the defective product acquisition circuit parameters and the corresponding current sensing resistor RS parameters, so that the current acquisition accuracy of the defective product acquisition circuit meets the preset acquisition accuracy standard.

[0024] Compared with the prior art, the present invention realizes independent collection of the battery voltage Vbat of the battery cell and the current sensing voltage Vrs flowing through the current sensing resistor RS by controlling the on and off of the switching circuit, and realizes detection of the defective product collection circuit based on the difference between the current sensing voltage Vrs and the theoretical current sensing voltage V0. It also corrects the defective product collection circuit parameters and the corresponding current sensing resistor RS parameters based on the current sensing current Irs of the current sensing resistor RS corresponding to the good product collection circuit, so that the current collection accuracy of the defective product collection circuit meets the preset collection accuracy standard. The detection process of the defective product collection circuit does not require manual intervention, avoiding missed detection of the defective product collection circuit due to human intervention, and effectively preventing safety hazards caused by missed detection of the defective product collection circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a circuit diagram of a current collection self-checking circuit based on BMS application of the present invention;

[0026] Figure 2 It is a flow chart of the current collection self-checking method based on BMS application of the present invention. DETAILED DESCRIPTION

[0027] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the embodiments and the accompanying drawings.

[0028] See also Figure 1 As shown, the current acquisition self-verification circuit based on BMS application of this embodiment includes a battery cell 1, a positive terminal 2, a negative terminal 3, a current sensing resistor RS, a switch circuit 4, a control circuit 5 and an acquisition circuit 6, wherein the positive terminal of the battery cell 1 is electrically connected to the positive terminal 2, and the negative terminal is electrically connected to the negative terminal 3 through the current sensing resistor RS. The switch circuit 4 is arranged in parallel between the positive terminal 2 and the negative terminal 3. The control circuit 5 is used to acquire the battery voltage Vbat of the battery cell 1 and to turn on the switch circuit 4 so that the battery cell 1, the switch circuit 4 and the current sensing resistor RS together constitute an acquisition circuit. The acquisition circuit 6 is used to acquire the current sensing voltage Vrs flowing through the current sensing resistor RS. The control circuit 5 is used to detect the current acquisition accuracy of the acquisition circuit 6 based on the difference between the current sensing voltage Vrs and the theoretical current sensing voltage V0.

[0029] It should be noted that the switch circuit 4 is in the off state by default and only switches from the off state to the on state after receiving a turn-on signal from the control circuit 5. Thus, the battery cell 1, the switch circuit 4, and the current-sense resistor RS together form a data acquisition circuit. The theoretical current-sense voltage V0 can be understood as the voltage generated across the current-sense resistor RS when the circuit accuracy is optimal.

[0030] Preferably, the switch circuit 4 includes a first resistor R1 and a switch unit Q1 , one end of the switch unit Q1 is electrically connected between the positive electrode of the battery unit 1 and the positive terminal 2 through the first resistor R1 , and the other end is electrically connected between the negative terminal 3 and the current sensing resistor RS.

[0031] Preferably, the control circuit 5 includes a control unit U1, which includes a first acquisition terminal and a control terminal. The first acquisition terminal is used to acquire the battery voltage Vbat of the battery unit 1, and the control terminal is used to control the on and off of the switch unit Q1. The control unit U1 here is a processing chip with data processing capabilities.

[0032] Preferably, the control circuit 5 also includes a fourth resistor R4 and a fifth resistor R5, one end of the fourth resistor R4 is electrically connected between the positive pole of the battery unit 1 and the switching circuit 4, and the other end is grounded through the fifth resistor R5, and the first acquisition end is electrically connected between the fourth resistor R4 and the fifth resistor R5.

[0033] Preferably, the first resistor R1 , the fourth resistor R4 and the fifth resistor R5 are all precision resistors. It is understandable that the error between the resistance values ​​of the precision resistors and the actual measured values ​​can be ignored.

[0034] The fourth resistor R4 and the fifth resistor R5 together form a voltage divider network. The control unit U1 actually collects the precise voltage value of the fifth resistor R5. The control unit U1 can accurately calculate the battery voltage Vbat of the battery unit 1 through the voltage divider ratio of the voltage divider network.

[0035] Preferably, the switch unit Q1 is a MOS transistor, the drain of the switch unit Q1 being electrically connected between the positive electrode of the battery cell 1 and the positive terminal 2 via the first resistor R1, the source being electrically connected between the negative terminal 3 and the current-sense resistor RS, and the gate being electrically connected to the control terminal. Of course, in other embodiments, the switch unit Q1 can be other types of switching elements that can be triggered on and off by the control terminal, which is not limited here.

[0036] After collecting the battery voltage Vbat of the battery cell 1, the control unit U1 outputs a high-level signal (i.e., the above-mentioned conduction signal) to the gate of the switch unit Q1. At this time, the switch unit Q1 is turned on, so that the battery cell 1, the switch circuit 4 and the current sensing resistor RS together constitute an acquisition loop.

[0037] Preferably, the acquisition circuit 6 includes an acquisition unit U2, which includes an acquisition terminal group and a first communication terminal. The control unit U1 also includes a second communication terminal. The acquisition terminal group is used to acquire the current-sense voltage Vrs of the current-sense resistor RS, and the first communication terminal is electrically connected to the second communication terminal. The acquisition unit U2 is a current acquisition chip.

[0038] Preferably, the acquisition circuit 6 further includes a second resistor R2 and a third resistor R3, and the acquisition terminal group includes a negative acquisition terminal and a positive acquisition terminal. The negative acquisition terminal is electrically connected between the negative electrode of the battery unit 1 and the current sensing resistor RS through the second resistor R2, and the positive acquisition terminal is electrically connected between the current sensing resistor RS and the switch unit Q1 through the third resistor R3.

[0039] Preferably, the acquisition circuit 6 further includes a sixth resistor R6 , one end of the sixth resistor R6 is electrically connected between the second resistor R2 and the current sensing resistor RS, and the other end of the sixth resistor R6 is electrically connected between the third resistor R3 and the current sensing resistor RS.

[0040] Preferably, the sixth resistor R6 is a precision resistor. When the switch unit Q1 is turned on so that the battery unit 1, the switch circuit 4, and the current-sense resistor RS together form a collection loop, the first resistor R1 generates a terminal voltage, and the current in the collection loop flows through the first resistor R1, the current-sense resistor RS, and the sixth resistor R6. At this time, the current-sense current I flowing through the current-sense resistor RS is Vbat / ((R1+R6) / RS), that is, the current-sense current I flowing through the current-sense resistor RS can be accurately calculated.

[0041] The current in the acquisition loop flows through the current-sense resistor RS and the sixth resistor R6, causing the current-sense resistor RS to generate a current-sense voltage Vrs. The acquisition unit U2 acquires the current-sense voltage Vrs and feeds it back to the control unit U1. The control unit U1 processes and calculates the error between the current-sense voltage Vrs fed back by the acquisition unit U2 and the theoretical current-sense voltage V0, determining whether the error is within the allowable error range (i.e., whether it meets the preset acquisition accuracy standard). If the error is within the correct range, the product is judged to be of good quality. Otherwise, it is judged to be defective and an alarm is issued.

[0042] Preferably, the current acquisition self-checking circuit based on BMS application also includes a DC-DC conversion unit 7, the input end of the DC-DC conversion unit 7 is electrically connected to the positive pole of the battery unit 1, and the output end is used to electrically connect to an external device for subsequent circuit expansion. For example, the battery voltage Vbat collected by the acquisition unit U2 is replaced with the voltage at the output end of the DC-DC conversion unit 7. At this time, this embodiment is for current acquisition and calibration at the output end of the DC-DC conversion unit 7.

[0043] See also Figure 1 and Figure 2 Accordingly, the present invention further discloses a current acquisition self-verification method based on BMS application, which is applied to the above current acquisition self-verification circuit based on BMS application. The current acquisition self-verification method based on BMS application includes the following steps:

[0044] S1, collecting the battery voltage Vbat of battery unit 1;

[0045] S2, turning on the switch circuit 4, so that the battery unit 1, the switch circuit 4 and the current sensing resistor RS together form a collection loop;

[0046] S3, collecting the current-sense voltage Vrs flowing through the current-sense resistor RS;

[0047] S4, detecting the current collection accuracy of the collection circuit 6 according to the difference between the current detection voltage Vrs and the theoretical current detection voltage V0;

[0048] S5. If the current acquisition accuracy of the acquisition circuit 6 does not meet the preset acquisition accuracy standard, the current acquisition circuit 6 is marked as a defective acquisition circuit 6 and a defect alarm is issued;

[0049] S6. If the current acquisition accuracy of the acquisition circuit 6 meets the preset acquisition accuracy standard, mark the current acquisition circuit 6 as a good acquisition circuit 6;

[0050] S7, calculating the current sense current Irs of the current sense resistor RS corresponding to the good product acquisition circuit 6 according to the battery voltage Vbat;

[0051] S8. According to the current sensing current Irs of the current sensing resistor RS corresponding to the good product acquisition circuit 6, calibrate the parameters of the defective product acquisition circuit 6 and the corresponding current sensing resistor RS parameters, so that the current acquisition accuracy of the defective product acquisition circuit 6 meets the preset acquisition accuracy standard.

[0052] It should be noted that the above-mentioned calibration of the defective product acquisition circuit 6 parameters and the corresponding current sensing resistor RS parameters can be automatically calibrated by using an instrument or manually, which is not limited here.

[0053] Combine Figure 1 and Figure 2 The present invention realizes independent collection of the battery voltage Vbat of the battery cell 1 and the current sensing voltage Vrs flowing through the current sensing resistor RS by controlling the on and off of the switch circuit 4, and realizes detection of the defective product collection circuit 6 based on the difference between the current sensing voltage Vrs and the theoretical current sensing voltage V0. It also corrects the parameters of the defective product collection circuit 6 and the corresponding parameters of the current sensing resistor RS based on the current sensing current Irs of the current sensing resistor RS corresponding to the good product collection circuit 6, so that the current collection accuracy of the defective product collection circuit 6 meets the preset collection accuracy standard. The detection process of the defective product collection circuit 6 does not require manual intervention, avoiding missed detection of the defective product collection circuit 6 due to human intervention, and effectively preventing safety hazards caused by missed detection of the defective product collection circuit 6.

[0054] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope of the present invention.

Claims

1. A current collection self-checking circuit based on BMS application, characterized by: The device comprises a battery cell, a positive electrode port, a negative electrode port, a current-sense resistor RS, a switch circuit, a control circuit, and an acquisition circuit. The positive electrode of the battery cell is electrically connected to the positive electrode port, and the negative electrode is electrically connected to the negative electrode port via the current-sense resistor RS. The switch circuit is arranged in parallel between the positive and negative electrode ports. The control circuit is used to acquire the battery voltage Vbat of the battery cell and to turn on the switch circuit so that the battery cell, the switch circuit, and the current-sense resistor RS together constitute an acquisition circuit. The acquisition circuit is used to acquire the current-sense voltage Vrs flowing through the current-sense resistor RS. The control circuit is used to detect the current acquisition accuracy of the acquisition circuit based on the difference between the current-sense voltage Vrs and the theoretical current-sense voltage VO. The current collection self-checking circuit based on the BMS application is used to perform a current collection self-checking method, which includes the following steps: Collect the battery voltage Vbat of the battery unit; Turn on the switch circuit so that the battery unit, the switch circuit and the current-sense resistor RS together form a collection loop; Collect the current-sense voltage Vrs flowing through the current-sense resistor RS; The current collection accuracy of the collection circuit is detected based on the difference between the current detection voltage Vrs and the theoretical current detection voltage V0; If the current acquisition accuracy of the acquisition circuit does not meet the preset acquisition accuracy standard, the current acquisition circuit is marked as a defective acquisition circuit and a defect alarm is issued; If the current acquisition accuracy of the acquisition circuit meets the preset acquisition accuracy standard, the current acquisition circuit is marked as a good acquisition circuit; Calculate the current sense current Irs of the current sense resistor RS corresponding to the good product acquisition circuit according to the battery voltage Vbat; According to the current sensing current Irs of the current sensing resistor RS corresponding to the good product acquisition circuit, the defective product acquisition circuit parameters and the corresponding current sensing resistor RS parameters are corrected to make the current acquisition accuracy of the defective product acquisition circuit meet the preset acquisition accuracy standard.

2. The current acquisition self-checking circuit based on BMS application according to claim 1, characterized in that: The switch circuit includes a first resistor R1 and a switch unit. One end of the switch unit is electrically connected between the positive electrode and the positive terminal of the battery unit through the first resistor R1, and the other end is electrically connected between the negative terminal and the current sensing resistor RS.

3. The current acquisition self-checking circuit based on BMS application according to claim 2, characterized in that: The control circuit includes a control unit. The control unit includes a first acquisition terminal and a control terminal. The first acquisition terminal is used to acquire the battery voltage Vbat of the battery unit. The control terminal is used to control the on and off of the switch unit.

4. The current acquisition self-checking circuit based on BMS application according to claim 3, characterized in that: The control circuit further includes a fourth resistor R4 and a fifth resistor R5. One end of the fourth resistor R4 is electrically connected between the positive electrode of the battery unit and the switching circuit, and the other end is grounded through the fifth resistor R5. The first acquisition end is electrically connected between the fourth resistor R4 and the fifth resistor R5.

5. The current acquisition self-checking circuit based on BMS application according to claim 3, characterized in that: The switch unit is a MOS tube, the drain of the switch unit is electrically connected between the positive electrode and the positive port of the battery unit through the first resistor R1, the source is electrically connected between the negative port and the current sensing resistor RS, and the gate is electrically connected to the control end.

6. The current acquisition self-checking circuit based on BMS application according to claim 3, characterized in that: The acquisition circuit includes an acquisition unit, which includes an acquisition terminal group and a first communication terminal. The control unit also includes a second communication terminal. The acquisition terminal group is used to acquire the current sensing voltage Vrs of the current sensing resistor RS. The first communication terminal is electrically connected to the second communication terminal.

7. The current acquisition self-checking circuit based on BMS application according to claim 6, characterized in that: The acquisition circuit further includes a second resistor R2 and a third resistor R3. The acquisition terminal group includes a negative electrode acquisition terminal and a positive electrode acquisition terminal. The negative electrode acquisition terminal is electrically connected between the negative electrode of the battery cell and the current sensing resistor RS through the second resistor R2. The positive electrode acquisition terminal is electrically connected between the current sensing resistor RS and the switch unit through the third resistor R3.

8. The current acquisition self-checking circuit based on BMS application according to claim 7, characterized in that: The acquisition circuit further includes a sixth resistor R6 , one end of which is electrically connected between the second resistor R2 and the current-sensing resistor RS, and the other end of which is electrically connected between the third resistor R3 and the current-sensing resistor RS.

9. The current acquisition self-checking circuit based on BMS application according to claim 1, characterized in that: It also includes a DC-DC conversion unit, the input end of the DC-DC conversion unit is electrically connected to the positive electrode of the battery unit, and the output end is used to electrically connect to an external device.

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