CN111371139A - State diagnosis circuit and method for equalization circuit - Google Patents
State diagnosis circuit and method for equalization circuit Download PDFInfo
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- CN111371139A CN111371139A CN202010129930.2A CN202010129930A CN111371139A CN 111371139 A CN111371139 A CN 111371139A CN 202010129930 A CN202010129930 A CN 202010129930A CN 111371139 A CN111371139 A CN 111371139A
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Abstract
The application provides a state diagnostic circuit of equalizer circuit, and regulating circuit's both ends are connected with the positive negative pole of electric core, and detection circuitry is connected with regulating circuit, and control module both ends are connected with regulating circuit, signal processing circuit respectively, and signal processing module both ends are connected with detection circuitry, power respectively, and the output signal conditioning of detection circuitry is the corresponding detected signal that control module can discern. In the state diagnosis process, the control module controls the equalizing circuit to be opened or closed, the battery management system obtains a first voltage and a first level state of the battery core when the equalizing circuit is opened, and a second voltage and a second level state when the equalizing circuit is closed, and then the battery management system compares the voltage difference between the first voltage and the second voltage, the first level state and the second level state with a preset threshold value and the level state corresponding to the opening and closing state of the equalizing circuit, so that the specific state of the equalizing circuit is identified, and the state monitoring of the equalizing circuit is effectively realized.
Description
Technical Field
The present disclosure relates to battery management technologies, and in particular, to a status diagnostic circuit and a status diagnostic method for an equalizing circuit.
Background
Because the lithium ion battery has the characteristics of small volume, high energy density, high internal resistance, high voltage, high cycle frequency, low self-discharge rate and the like, the lithium ion battery is widely applied to occasions such as electric vehicles, traffic tracks and the like in recent years. In application, because the battery is a battery pack formed by combining a plurality of single lithium ion batteries, and the inconsistency of each single battery is considered, the single voltage deviation of the lithium ion battery is kept within an expected range by adopting a balancing measure, so that each single battery is kept in the same state in normal use.
The existing battery management system does not make extra diagnosis for the equalization circuit itself, and only relies on analog Acquisition Front End (AFE) for detection. The diagnostic function of the AFE cannot specifically diagnose the abnormal state of the equalization circuit, and only can judge whether the equalization circuit is turned on or off, and the state monitoring of the equalization circuit cannot be effectively realized.
Disclosure of Invention
The present disclosure is directed to a circuit and a method for diagnosing a state of an equalizer circuit, and aims to overcome a drawback that a specific state of the equalizer circuit cannot be diagnosed in an existing battery management system.
In order to achieve the above object, the present application provides a state diagnosis circuit of an equalization circuit, including a signal processing circuit, a control module, at least two groups of detection circuits, and at least two groups of adjustment circuits, where one group of detection circuit and adjustment circuit corresponds to one battery cell;
two ends of the regulating circuit are connected with the positive electrode and the negative electrode of the battery cell and used for regulating the voltage of the battery cell;
the detection circuit is connected with the regulating circuit and used for judging the conduction state of the regulating circuit;
one end of the control module is connected with the adjusting circuit, and the other end of the control module is connected with the signal processing circuit and used for controlling the adjusting action of the adjusting circuit and receiving the detection signal transmitted by the signal processing circuit;
one end of the signal processing circuit is connected with the detection circuit, and the other end of the signal processing circuit is connected with the power supply and used for conditioning the output signal of the detection circuit into the detection signal corresponding to the control module.
Further, the regulating circuit comprises a diagnosis resistor, an equalizing switch tube, a first diode and an equalizing resistor;
one end of the diagnosis resistor is connected with the anode of the battery cell, and the other end of the diagnosis resistor is connected with the balance switch tube and is used for diagnosing whether the balance switch tube acts or not;
the balance switch tube, the first diode, the balance resistor and the negative electrode of the battery cell are sequentially connected, the balance switch tube and the balance resistor are used for reducing the voltage of the battery cell, and the first diode is used for preventing the negative current of the battery cell from flowing backwards.
Furthermore, the balance switch tube is an MOS tube or a triode;
when the equalizing switch tube is an MOS tube, the output end of the diagnosis resistor is connected with the S pole of the equalizing switch tube, the anode of the first diode is connected with the D pole of the equalizing switch tube, and the control module is connected with the G pole of the equalizing switch tube;
when the balance switch tube is a triode, the output end of the diagnosis resistor is connected with the E pole of the balance switch tube, the anode of the first diode is connected with the C pole of the balance switch tube, and the control module is connected with the B pole of the balance switch tube.
Further, the detection circuit comprises a first resistor, a second resistor, a third resistor, a diagnosis switch tube and a second diode;
the diagnosis switch tube is an MOS tube or a triode;
when the diagnosis switch tube is an MOS tube, the D pole of the diagnosis switch tube is connected with one end of the first resistor, the G pole of the diagnosis switch tube is connected with one end of the second resistor and one end of the third resistor, and the S pole of the diagnosis switch tube is connected with the anode of the second diode and the other end of the third resistor;
when the diagnosis switch tube is a triode, the C pole of the diagnosis switch tube is connected with one end of the first resistor, the B pole of the diagnosis switch tube is connected with one end of the second resistor and one end of the third resistor, and the E pole of the diagnosis switch tube is connected with the anode of the second diode and the other end of the third resistor;
the other end of the first resistor is connected with the second resistor;
the other end of the second resistor is connected with the equalizing switch tube;
and the cathode of the second diode is connected with the signal processing circuit.
Furthermore, the signal processing circuit comprises a fourth resistor, a fifth resistor, a first switching tube and a capacitor;
the first switch tube is an MOS tube or a triode;
when the first switching tube is an MOS tube, the G pole of the first switching tube is connected with the negative pole of the second diode, the D pole of the first switching tube is connected with one end of the fifth resistor and the control module, and the S pole of the first switching tube is grounded;
when the first switch tube is a triode, the B pole of the first switch tube is connected with the negative pole of the second diode, the C pole of the first switch tube is connected with one end of the fifth resistor and the control module, and the E pole of the first switch tube is grounded;
one end of the fourth resistor is connected with the cathode of the second diode, and the other end of the fourth resistor is grounded;
one end of the capacitor is connected with the cathode of the second diode, and the other end of the capacitor is grounded;
the other end of the fifth resistor is connected with the power supply.
Further, the control module comprises an AFE and an MCU, and the AFE is in signal connection with the MCU;
when the balance switch tube and the first switch tube are both MOS tubes, the AFE is connected with the G pole of the balance switch tube, and the MCU is connected with the D pole of the first switch tube;
when the balance switch tube and the first switch tube are both triodes, the AFE is connected with the B pole of the balance switch tube, and the MCU is connected with the C pole of the first switch tube.
The present application further provides a state diagnosis method for an equalization circuit, based on the state diagnosis circuit for an equalization circuit in any one of the above, the method including:
respectively acquiring a first voltage and a first level state of a battery cell when the balance is started, and a second voltage and a second level state when the balance is closed;
calculating a voltage difference between the first voltage and the second voltage;
and taking the voltage difference, the first level state and/or the second level state as diagnosis parameters, and substituting the diagnosis parameters into a preset algorithm respectively to obtain the state of the equalization circuit.
Further, the step of obtaining the state of the equalization circuit by taking the voltage difference, the first level state and/or the second level state as diagnostic parameters and respectively substituting into a preset algorithm includes:
judging whether the voltage difference is smaller than a threshold value;
if the voltage difference is smaller than a threshold value, judging whether the first level state is a high level or not, or whether the second level state is a low level or not;
if the first level state is a high level, judging that the state of the equalizing circuit is open;
and if the second level state is a low level, judging that the state of the equalizing circuit is leakage.
Further, after the step of determining whether the voltage difference is smaller than the threshold, the method includes:
if the voltage difference is not less than the threshold value, judging whether the first level state and/or the second level state is a low level;
if the first level state is a low level, judging that the state of the equalizing circuit is normally started;
and if the second level state is a high level, judging that the state of the equalizing circuit is normally closed.
Preferably, the threshold is 50 mv.
According to the state diagnosis circuit and method of the equalization circuit, two ends of the adjusting circuit are connected with the positive electrode and the negative electrode of the battery cell, and electric quantity of the battery cell is consumed when equalization is started. The detection circuit is connected with the regulating circuit and can diagnose the conduction state in the regulating circuit. Two ends of the control module are respectively connected with the regulating circuit and the signal processing circuit, so that the action of the regulating circuit is controlled, and the detection signal transmitted by the signal processing circuit is received. Two ends of the signal processing module are respectively connected with the detection circuit and the power supply, and output signals of the detection circuit are conditioned into corresponding detection signals which can be identified by the control module. In the state diagnosis process, the control module controls the equalizing circuit to be opened or closed, the battery management system obtains a first voltage and a first level state of the battery core when the equalizing circuit is opened, and a second voltage and a second level state when the equalizing circuit is closed, and then the battery management system compares the voltage difference between the first voltage and the second voltage, the first level state and the second level state with a preset threshold value and the level state corresponding to the opening and closing state of the equalizing circuit, so that the specific state of the equalizing circuit is identified, and the state monitoring of the equalizing circuit is effectively realized.
Drawings
Fig. 1 is a specific circuit diagram of a status diagnosis circuit of an equalization circuit according to an embodiment of the present application;
FIG. 2 is a functional block diagram of a status diagnostic circuit of the equalization circuit in an embodiment of the present application;
fig. 3 is a flowchart illustrating a method for diagnosing a state of an equalizer circuit according to an embodiment of the present disclosure.
The implementation, functional features and advantages of the objectives of the present application will be further explained with reference to the accompanying drawings.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Referring to fig. 1 and 2, in an embodiment of the present application, a state diagnosis circuit of an equalization circuit is provided, including a signal processing circuit 3, a control module 4, at least two groups of detection circuits 2, and at least two groups of adjustment circuits 1, where one group of detection circuits 2 and one group of adjustment circuits 1 correspond to one battery cell;
two ends of the regulating circuit 1 are connected with the positive electrode and the negative electrode of the battery cell and used for regulating the voltage of the battery cell;
the detection circuit 2 is connected with the adjusting circuit 1 and is used for judging the conducting state of the adjusting circuit 1;
one end of the control module 4 is connected with the adjusting circuit 1, and the other end of the control module is connected with the signal processing circuit 3, and is used for controlling the adjusting action of the adjusting circuit 1 and receiving the detection signal transmitted by the signal processing circuit 3;
one end of the signal processing circuit 3 is connected with the detection circuit 2, and the other end is connected with the power supply, and is used for conditioning the output signal of the detection circuit 2 into the detection signal corresponding to the control module 4.
In this embodiment, the state diagnosis circuit includes a signal processing circuit, a control module 4, at least two sets of detection circuits 2 and at least two sets of adjustment circuits 1, one set of detection circuit 2 and one set of adjustment circuit 1 correspond to one battery cell, and the multiple sets of detection circuits 2 and the multiple sets of adjustment circuits 1 may be connected to one set of signal processing circuit 3 and the control module 4 together. Specifically, two ends of the adjusting circuit 1 are connected to the positive electrode and the negative electrode of the battery cell, and are used for discharging the battery cell, so that the voltage of the battery cell is adjusted. The detection circuit 2 is connected to the regulating circuit 1 for diagnosing the switching state in the regulating circuit 1. One end of the control module 4 is connected with the regulating circuit 1, and the other end is connected with the signal processing circuit 3, so that the regulating action of the regulating circuit 1, such as the switching of a switch, is controlled by a signal. Signal processingOne end of the circuit 3 is connected with the detection circuit 2, and the other end is connected with an external power supply. Since the detection signal directly output by the detection circuit 2 may be a high voltage, it is not allowed to be sent to the control module 4 for identification, otherwise the control module 4 may be damaged. Therefore, the detection signal output by the detection circuit 2 needs to be conditioned correspondingly by the signal processing circuit 3, so that the detection signal can be detected by the detection module and then input into the control module 4, thereby obtaining a detection result corresponding to the detection signal. Referring to fig. 1, the battery generally includes a plurality of groups of battery cells, the state diagnosis circuit of each group of battery cells includes a group of detection circuit 2 and adjustment circuit 1, and the control module 4 and the signal processing circuit 3 may be only one group, and the connection relationship of the circuits is as described above. Taking one of the battery cells as an example for explanation, when detection is performed, the MCU in the control module 4 sends a signal to the AFE through communication, and starts the equalization of the nth battery cell in the battery, at this time, the equalization switch tube Q1 in the adjustment circuit 1 is turned on, and the electric quantity of the nth battery cell is consumed through the equalization resistor R1. Meanwhile, when the equalizing switch Q1 is turned on, the diagnosing switch Q2 and the first switch Q5 are turned on sequentially, and the level signal S1 is pulled low to be "0". When the equalizing switch tube Q1 is turned off, that is, the switch tubes in the state diagnostic circuit corresponding to the nth cell are all turned off, the state of the level signal S1 is "1". Meanwhile, the control module 4 monitors the first voltage and the second voltage corresponding to the nth power core when the power core is balanced to be switched on and off, and then the state of the balancing circuit corresponding to the nth power core is obtained through diagnosis according to the voltage difference when the power core is balanced to be switched on and switched off and the state of the corresponding level signal. Referring to fig. 1, when the equalization is turned on, a voltage drop is generated across the diagnostic resistors R3, R4, and R7, and the MCU can determine whether the equalization is turned on or off by the voltage drop. Selecting reference conditions for diagnosing resistance values of the resistors: diagnosing the voltage drop V across the resistor when acting in equilibriumDSignificant changes should occur. According to the calculation formula:
R3＝VD*R1/(Vcell-VCE–VF-VD)
in the formula, VFIs D1 forward conduction voltage drop, VCETo equalize the conduction voltage drop of the switching tube Q1.
Suppose that: vD＝100mV；Vcell＝3V；VF＝0.8V；VCE0.2V; the equalization resistor value is 50 ohms, and the diagnostic resistor value can take 3 ohms.
The value of the fourth resistor R10 requires that: consider the CE leakage current I of Q2leak_CE2；
Maximum value of R10: r10max＝VQ5_th/(n*Ileak_CE2)；
In the formula: vQ5_thIs the driving voltage when Q5 is critical conducting; n is the number of battery strings;
the value of the third resistor R12 requires that: reference D1 reverse leakage current Ileak_D1And CE leakage current I of Q1leak_CE1；
Maximum value of R12: r12max＝VQ2_th/(Ileak_D1+Ileak_CE2)；
In the formula: vQ2_thIs the driving voltage when Q2 is critical conducting;
the values of R8 and R2 need to refer to the resistance values of R12 and R10, and the voltage values of R12 and R10 are calculated, so that the Q2 and Q5 can be normally conducted.
Further, the regulating circuit 1 comprises a diagnosis resistor, an equalization switching tube, a first diode and an equalization resistor;
one end of the diagnosis resistor is connected with the anode of the battery cell, and the other end of the diagnosis resistor is connected with the balance switch tube and is used for diagnosing whether the balance switch tube acts or not;
the balance switch tube, the first diode, the balance resistor and the negative electrode of the battery cell are sequentially connected, the balance switch tube and the balance resistor are used for reducing the voltage of the battery cell, and the first diode is used for preventing the negative current of the battery cell from flowing backwards.
Referring to fig. 1, in this embodiment, the adjusting circuit 1 includes a diagnostic resistor R3, an equalizing switch Q1, a first diode D1, and an equalizing resistor R1, specifically, one end of the diagnostic resistor R3 is connected to the positive electrode of the battery cell, and the other end of the diagnostic resistor R3 is connected to the equalizing switch Q1, when the equalizing circuit is turned on, that is, the equalizing switch Q1 is turned on, a voltage drop is generated across the diagnostic resistor R3, so that the control module 4 can diagnose whether the equalizing switch Q1 is turned on or off according to a change in the voltage drop across the diagnostic resistor R3. However, the diagnostic resistor R3 can only be used to diagnose whether the equalizing switch Q1 is activated, and it is impossible to determine whether the equalizing switch Q1 is not turned on or off. The end of the equalizing switch tube Q1, which is not connected with the diagnostic resistor R3, is connected with the anode of the first diode D1, the cathode of the first diode D1 is connected with one end of the equalizing resistor R1, and the other end of the equalizing resistor R1 is sequentially connected with the cathode of the battery cell. When the voltage of the battery cell communicated by the regulating circuit 1 is higher and the electric energy needs to be consumed, the equalizing switch tube Q1 is switched on, and the equalizing resistor R1 consumes the electric energy to discharge electricity to the battery cell, so that the voltage reduction of the battery cell is realized. The diode D1 can prevent the voltage of the negative electrode of the battery cell from flowing back to the regulating circuit 1, and if the first diode D1 is not provided, the voltage of the negative electrode of the battery cell can also turn on the diagnosis switch Q2, so that the state diagnosis of the equalizing circuit cannot be realized.
Furthermore, the balance switch tube is an MOS tube or a triode;
when the equalizing switch tube is an MOS tube, the output end of the diagnosis resistor is connected with the S pole of the equalizing switch tube, the anode of the first diode is connected with the D pole of the equalizing switch tube, and the control module 4 is connected with the G pole of the equalizing switch tube;
when the equalizing switch tube is a triode, the output end of the diagnosis resistor is connected with the E pole of the equalizing switch tube, the anode of the first diode is connected with the C pole of the equalizing switch tube, and the control module 4 is connected with the B pole of the equalizing switch tube.
In this embodiment, the equalizing switch tube may be an MOS tube or a triode. Specifically, when the equalizing switch tube Q1 is a MOS tube, the S-pole of the equalizing switch tube Q1 is connected to the output end of the diagnostic resistor R3; the D pole of the equalizing switch tube Q1 is connected with the positive pole of a first diode D1; the G pole of the equalizing switch Q1 is connected to the control module 4. When the equalizing switch tube Q1 is a triode, the E pole of the equalizing switch tube Q1 is connected to the output end of the diagnostic resistor R3, the C pole is connected to the positive pole of the first diode D1, and the B pole is connected to the control module 4. The equalizing switch tube Q1 receives the control signal of the control module 4 to perform a corresponding opening and closing action, so as to open and close the equalizing circuit corresponding to the battery cell.
Further, the detection circuit 2 comprises a first resistor, a second resistor, a third resistor, a diagnosis switch tube and a second diode;
the diagnosis switch tube is an MOS tube or a triode;
when the diagnosis switch tube is an MOS tube, the D pole of the diagnosis switch tube is connected with one end of the first resistor, the G pole of the diagnosis switch tube is connected with one end of the second resistor and one end of the third resistor, and the S pole of the diagnosis switch tube is connected with the anode of the second diode and the other end of the third resistor;
when the diagnosis switch tube is a triode, the C pole of the diagnosis switch tube is connected with one end of the first resistor, the B pole of the diagnosis switch tube is connected with one end of the second resistor and one end of the third resistor, and the E pole of the diagnosis switch tube is connected with the anode of the second diode and the other end of the third resistor;
the other end of the first resistor is connected with the second resistor;
the other end of the second resistor is connected with the equalizing switch tube;
the cathode of the second diode is connected with the signal processing circuit 3.
Referring to fig. 1, in the present embodiment, the detection circuit 2 includes a first resistor R2, a second resistor R8, a third resistor R12, a diagnostic switch Q2, and a second diode D2, wherein the diagnostic switch Q2 may be a MOS transistor or a triode. Specifically, when the diagnostic switch Q2 is a MOS transistor, the D-pole of the diagnostic switch Q2 is connected to one end of the first resistor R2, the G-pole of the diagnostic switch Q2 is connected to one end of the second resistor R8 and one end of the third resistor R12, and the S-pole of the diagnostic switch Q2 is connected to the anode of the second diode D2 and the other end of the third resistor R12. When the diagnosis switch tube Q2 is a triode, the C pole of the diagnosis switch tube Q2 is connected with one end of the first resistor R2, the B pole of the diagnosis switch tube Q2 is connected with one end of the second resistor R8 and one end of the third resistor R12, and the E pole of the diagnosis switch tube Q2 is connected with the anode of the second diode D2 and the other end of the third resistor R12. The other end of the first resistor R2 is connected with a second resistor R8; the other end of the second resistor R8 is connected with a balanced switch tube Q2; the cathode of the second diode D2 is connected to the signal processing circuit 3. When the equalizing switch Q1 is turned on, the current flows through the equalizing switch Q1 to the second resistor R8, so that the diagnostic switch Q2 is turned on, and the current flows through the second diode D2 to turn on the first switch Q5, so that the output level signal S1 is changed in state. In the process, the control module 4 diagnoses the conducting state of the equalizing switch tube Q1 by detecting the current flowing state of the circuit 2 through the first resistor R2 and the third resistor R12, so as to determine whether the equalizing switch tube Q1 is currently on or off.
Further, the signal processing circuit 3 includes a fourth resistor, a fifth resistor, a first switch tube and a capacitor;
the first switching tube Q5 is an MOS tube or a triode;
when the first switching tube is an MOS tube, the G pole of the first switching tube is connected to the negative pole of the second diode, the D pole of the first switching tube is connected to one end of the fifth resistor and the control module 4, and the S pole of the first switching tube is grounded;
when the first switch tube is a triode, the B pole of the first switch tube is connected with the negative pole of the second diode, the C pole of the first switch tube is connected with one end of the fifth resistor and the control module 4, and the E pole of the first switch tube is grounded;
one end of the fourth resistor is connected with the cathode of the second diode, and the other end of the fourth resistor is grounded;
one end of the capacitor is connected with the cathode of the second diode, and the other end of the capacitor is grounded;
the other end of the fifth resistor is connected with the power supply.
In this embodiment, the signal processing circuit 3 includes a fourth resistor R10, a fifth resistor R11, a first switch Q5, and a capacitor C1, wherein the first switch Q5 may be a MOS transistor or a triode. Specifically, when the first switch Q5 is a MOS transistor, the G-pole of the first switch Q5 is connected to the negative electrode of the second diode D2, the D-pole of the first switch Q5 is connected to one end of the fifth resistor R11 and the control module 4, and the S-pole of the first switch Q5 is grounded. When the first switch tube Q5 is a triode, the B pole of the first switch tube Q5 is connected to the negative pole of the second diode D2, the C pole of the first switch tube Q5 is connected to one end of the fifth resistor R11 and the control module 4, and the E pole of the first switch tube Q5 is grounded. One end of the fourth resistor R10 is connected to the cathode of the second diode D1, and the other end is grounded. One end of the capacitor C1 is connected with the cathode of the second diode D2, and the other end is grounded; the other end of the fifth resistor R11 is connected with a power supply. The output voltage of the diagnostic switch Q2 may be a relatively high voltage that is not allowed to be directly sent to the control module 4 for detection, and therefore must be converted to a safe voltage. Specifically, when the equalizing switch Q1 is turned on, the base of the diagnosing switch Q2 has a voltage, which makes the diagnosing switch Q2 turned on, and at the same time, the base of the first switch Q5 also has a voltage, so that the first switch Q5 is also turned on, and at this time, the state of the level signal S1 changes to "0", that is, the output voltage is smaller than a first preset threshold, for example, 0.3V. When the equalizing switch Q1 is turned off, the diagnosing switch Q2 and the first switch Q5 are also turned off, and the level signal changes to be in the state "1", i.e., the output voltage is higher than the second preset threshold and smaller than the third preset threshold. Preferably, the second preset threshold is 0.7V, and the third preset threshold is 1.0V. The fourth resistor R10 is a base pull-down resistor of the first switch Q5, and the capacitor C1 is a base pull-down capacitor of the first switch Q5, both of which are used to prevent the Q5 from being turned on by mistake. The fifth resistor R11 is a pull-up resistor of the level signal S1, and when the first switch Q5 is turned on, the level signal S1 is pulled down by the Q5 to assume a state "0"; when the first switch Q5 is turned off, the level signal S1 is pulled high by the fifth resistor R11, and the state "1" is assumed.
Further, the control module 4 comprises an AFE and an MCU, and the AFE is in signal connection with the MCU;
when the balance switch tube and the first switch tube are both MOS tubes, the AFE is connected with the G pole of the balance switch tube, and the MCU is connected with the D pole of the first switch tube;
when the balance switch tube and the first switch tube are both triodes, the AFE is connected with the B pole of the balance switch tube, and the MCU is connected with the C pole of the first switch tube.
In this embodiment, the control module 4 includes an AFE and an MCU, wherein the AFE and the MCU are in signal connection. When the equalizing switch tube Q1 and the first switch tube Q5 are MOS tubes, the AFE is connected to the G-pole of the equalizing switch tube Q1, and the MCU is connected to the D-pole of the first switch tube Q5. When the equalizing switch tube Q1 and the first switch tube Q5 are both triodes, the AFE is connected with the B pole of the equalizing switch tube Q1, and the MCU is connected with the C pole of the first switch tube Q5. In the state diagnosis process, the MCU sends a control signal to the AFE through communication, so that the equalizing circuit of the nth cell in the battery is turned on or off through the AFR. And after receiving the output voltage conditioned by the signal processing circuit 3, the MCU obtains a level signal corresponding to the equalization circuit of the nth cell after being turned on or off, thereby facilitating subsequent state diagnosis of the equalization circuit.
In the state diagnosis circuit of the equalization circuit provided in this embodiment, two ends of the adjusting circuit 1 are connected to the positive electrode and the negative electrode of the battery cell, and the electric quantity of the battery cell is consumed when the equalization is started. The detection circuit 2 is connected in parallel to the regulator circuit 1, and can diagnose the switching state inside the regulator circuit 1. Two ends of the control module 4 are respectively connected with the adjusting circuit 1 and the signal processing circuit 3, so as to control the action of the adjusting circuit 1 and receive the detection signal transmitted by the signal processing circuit 3. Two ends of the signal processing module are respectively connected with the detection circuit 2 and the power supply, and the output signal of the detection circuit 2 is conditioned into a corresponding detection signal which can be identified by the control module 4. In the state diagnosis process, the control module 4 controls the equalizing circuit to be opened or closed, the battery management system obtains a first voltage and a first level state of the battery cell when the equalizing circuit is opened, and a second voltage and a second level state when the equalizing circuit is closed, and then the battery management system compares the voltage difference between the first voltage and the second voltage, the first level state and the second level state with a preset threshold value and a level state corresponding to the opening and closing state of the equalizing circuit, so that the specific state of the equalizing circuit is identified, and the state monitoring of the equalizing circuit is effectively realized.
Referring to fig. 2, an embodiment of the present application further provides a state diagnosis method for an equalization circuit, where the method includes:
s1: respectively acquiring a first voltage and a first level state of a battery cell when the balance is started, and a second voltage and a second level state when the balance is closed;
s2: calculating a voltage difference between the first voltage and the second voltage;
s3: and taking the voltage difference, the first level state and/or the second level state as diagnosis parameters, and substituting the diagnosis parameters into a preset algorithm respectively to obtain the state of the equalization circuit.
In this embodiment, the MCU in the control module 4 sends the control signal to the AFE through communication, and the AFE correspondingly turns on and/or off the equalization of the nth power saving core after receiving the control signal. In the on/off process of the balancing circuit, a first voltage and a first level state of the battery cell during the on balancing are respectively obtained. And when the nth battery cell is balanced in a closed state, acquiring the current second voltage and the current second level state of the battery cell. The first voltage and the second voltage can be obtained by monitoring two ends of the regulating circuit 1, and can be obtained by measuring through a built-in or external voltage monitoring instrument. The first level state and the second level state can be detected by the detection circuit 2, and are subjected to corresponding signal conditioning by the signal processing circuit 3, so that the first level state and the second level state are converted into detection signals which can be identified by the control module 4, and the control module 4 can obtain the level states corresponding to the equalization circuit when the equalization circuit is opened and closed. The specific level signal detection and conditioning processes are as described above and will not be described in detail here. A preset algorithm for state diagnosis is arranged in the control module 4, and the state of the equalization circuit needs to be diagnosed according to the voltage difference between the first voltage and the second voltage, the first level state and the second level state, wherein the preset algorithm is recorded by a designer. The control module 4 calculates a voltage difference between the first voltage and the second voltage according to the first voltage and the second voltage. Then, the control module 4 uses the voltage difference, the first level state when the equalization is turned on, and/or the second level state when the equalization is turned off as diagnosis parameters, and substitutes the diagnosis parameters into a preset algorithm respectively, so as to obtain the state of the equalization circuit through diagnosis. Specifically, the control module 4 first determines whether the voltage difference is less than a threshold value. If the voltage difference is smaller than the threshold value, whether the first level state or the second level state is a high level is judged. And if the first level state is high level, judging that the state of the equalizing circuit is open. And if the second level state is low level, judging that the state of the equalizing circuit is leakage. If the voltage difference is not less than the threshold, whether the first level state or the second level state is a low level is judged. And if the first level state is a low level, judging that the state of the equalizing circuit is normally started. And if the second level state is a high level, judging that the state of the equalizing circuit is normally closed. The control module 4 completes the state diagnosis of the equalization circuit corresponding to the nth power core according to the preset algorithm and the diagnosis parameter.
Further, the step of obtaining the state of the equalization circuit by taking the voltage difference, the first level state and/or the second level state as diagnostic parameters and respectively substituting into a preset algorithm includes:
s301: judging whether the voltage difference is smaller than a threshold value;
s302: if the voltage difference is smaller than a threshold value, judging whether the first level state is a high level or not, or whether the second level state is a low level or not;
s303: if the first level state is a high level, judging that the state of the equalizing circuit is open;
s304: and if the second level state is a low level, judging that the state of the equalizing circuit is leakage.
In this embodiment, the control module 4 first determines whether a voltage difference between the first voltage and the second voltage is smaller than a threshold. The threshold value is preferably 50mv, and is recorded after corresponding calculation according to the circuit by a designer in advance. If the voltage difference is smaller than the threshold, the control module 4 determines whether the first level state corresponding to the equalization circuit is at a high level when the equalization circuit is turned on, or whether the second level state corresponding to the equalization circuit is at a low level when the equalization circuit is turned off. And if the first level state is a high level, judging that the state corresponding to the equalization circuit is an open circuit, and at the moment, the equalization cannot be started, wherein the most possible abnormality is that the equalization switch tube is broken and fails. And if the second level state is a low level, judging that the state of the equalizing circuit is leakage, and at the moment, the equalizing circuit cannot be closed, wherein the most possible abnormity is short-circuit failure of the equalizing switch tube.
Further, after the step of determining whether the voltage difference is smaller than the threshold, the method includes:
s305: if the voltage difference is not less than the threshold value, judging whether the first level state and/or the second level state is a low level;
s306: if the first level state is a low level, judging that the state of the equalizing circuit is normally started;
s307: and if the second level state is a high level, judging that the state of the equalizing circuit is normally closed.
In this embodiment, after comparing the voltage difference with the threshold, if the voltage difference is determined to be not less than the threshold, the control module 4 performs corresponding detection on the first level state and/or the second level state, and determines whether the two are low levels respectively. And if the first level state is low level at the moment, judging that the state of the equalizing circuit is normally started. And if the second level state is a high level, the state of the equalization circuit is determined to be normally closed. Namely, in the two cases, the normal operation of the equalizing circuit corresponding to the nth power saving core can be diagnosed.
In the state diagnosis method for the equalization circuit provided in this embodiment, two ends of the adjusting circuit 1 are connected to the positive electrode and the negative electrode of the battery cell, and the electric quantity of the battery cell is consumed when equalization is started. The detection circuit 2 is connected in parallel to the regulator circuit 1, and can diagnose the switching state inside the regulator circuit 1. Two ends of the control module 4 are respectively connected with the adjusting circuit 1 and the signal processing circuit 3, so as to control the action of the adjusting circuit 1 and receive the detection signal transmitted by the signal processing circuit 3. Two ends of the signal processing module are respectively connected with the detection circuit 2 and the power supply, and the output signal of the detection circuit 2 is conditioned into a corresponding detection signal which can be identified by the control module 4. In the state diagnosis process, the control module 4 controls the equalizing circuit to be opened or closed, the battery management system obtains a first voltage and a first level state of the battery cell when the equalizing circuit is opened, and a second voltage and a second level state when the equalizing circuit is closed, and then the battery management system compares the voltage difference between the first voltage and the second voltage, the first level state and the second level state with a preset threshold value and a level state corresponding to the opening and closing state of the equalizing circuit, so that the specific state of the equalizing circuit is identified, and the state monitoring of the equalizing circuit is effectively realized.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, apparatus, article, or method. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, apparatus, article, or method that includes the element.
The above description is only for the preferred embodiment of the present application and not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application, or which are directly or indirectly applied to other related technical fields, are intended to be included within the scope of the present application.
Claims (10)
1. A state diagnosis circuit of an equalization circuit is characterized by comprising a signal processing circuit, a control module, at least two groups of detection circuits and at least two groups of adjusting circuits, wherein one group of detection circuits and one group of adjusting circuits correspond to a battery cell;
two ends of the regulating circuit are connected with the positive electrode and the negative electrode of the battery cell and used for regulating the voltage of the battery cell;
the detection circuit is connected with the regulating circuit and used for judging the conduction state of the regulating circuit;
one end of the control module is connected with the adjusting circuit, and the other end of the control module is connected with the signal processing circuit and used for controlling the adjusting action of the adjusting circuit and receiving the detection signal transmitted by the signal processing circuit;
one end of the signal processing circuit is connected with the detection circuit, and the other end of the signal processing circuit is connected with the power supply and used for conditioning the output signal of the detection circuit into the detection signal corresponding to the control module.
2. The status diagnostic circuit of the equalizing circuit according to claim 1, wherein the regulating circuit comprises a diagnostic resistor, an equalizing switch tube, a first diode, and an equalizing resistor;
one end of the diagnosis resistor is connected with the anode of the battery cell, and the other end of the diagnosis resistor is connected with the balance switch tube and is used for diagnosing whether the balance switch tube acts or not;
the balance switch tube, the first diode, the balance resistor and the negative electrode of the battery cell are sequentially connected, the balance switch tube and the balance resistor are used for reducing the voltage of the battery cell, and the first diode is used for preventing the negative current of the battery cell from flowing backwards.
3. The status diagnostic circuit of the equalizing circuit according to claim 2, wherein the equalizing switch is a MOS transistor or a triode;
when the equalizing switch tube is an MOS tube, the output end of the diagnosis resistor is connected with the S pole of the equalizing switch tube, the anode of the first diode is connected with the D pole of the equalizing switch tube, and the control module is connected with the G pole of the equalizing switch tube;
when the balance switch tube is a triode, the output end of the diagnosis resistor is connected with the E pole of the balance switch tube, the anode of the first diode is connected with the C pole of the balance switch tube, and the control module is connected with the B pole of the balance switch tube.
4. The status diagnostic circuit of the equalizing circuit according to claim 3, wherein the detection circuit includes a first resistor, a second resistor, a third resistor, a diagnostic switch tube, and a second diode;
the diagnosis switch tube is an MOS tube or a triode;
when the diagnosis switch tube is an MOS tube, the D pole of the diagnosis switch tube is connected with one end of the first resistor, the G pole of the diagnosis switch tube is connected with one end of the second resistor and one end of the third resistor, and the S pole of the diagnosis switch tube is connected with the anode of the second diode and the other end of the third resistor;
when the diagnosis switch tube is a triode, the C pole of the diagnosis switch tube is connected with one end of the first resistor, the B pole of the diagnosis switch tube is connected with one end of the second resistor and one end of the third resistor, and the E pole of the diagnosis switch tube is connected with the anode of the second diode and the other end of the third resistor;
the other end of the first resistor is connected with the second resistor;
the other end of the second resistor is connected with the equalizing switch tube;
and the cathode of the second diode is connected with the signal processing circuit.
5. The status diagnostic circuit of the equalizing circuit according to claim 4, wherein the signal processing circuit comprises a fourth resistor, a fifth resistor, a first switching tube and a capacitor;
the first switch tube is an MOS tube or a triode;
when the first switching tube is an MOS tube, the G pole of the first switching tube is connected with the negative pole of the second diode, the D pole of the first switching tube is connected with one end of the fifth resistor and the control module, and the S pole of the first switching tube is grounded;
when the first switch tube is a triode, the B pole of the first switch tube is connected with the negative pole of the second diode, the C pole of the first switch tube is connected with one end of the fifth resistor and the control module, and the E pole of the first switch tube is grounded;
one end of the fourth resistor is connected with the cathode of the second diode, and the other end of the fourth resistor is grounded;
one end of the capacitor is connected with the cathode of the second diode, and the other end of the capacitor is grounded;
the other end of the fifth resistor is connected with the power supply.
6. The status diagnostic circuit of the equalization circuit according to claim 5, wherein the control module comprises an AFE and an MCU, the AFE and the MCU being in signal connection;
when the balance switch tube and the first switch tube are both MOS tubes, the AFE is connected with the G pole of the balance switch tube, and the MCU is connected with the D pole of the first switch tube;
when the balance switch tube and the first switch tube are both triodes, the AFE is connected with the B pole of the balance switch tube, and the MCU is connected with the C pole of the first switch tube.
7. A state diagnosis method of an equalization circuit, based on the state diagnosis circuit of the equalization circuit according to any one of claims 1 to 6, the method comprising:
respectively acquiring a first voltage and a first level state of a battery cell when the balance is started, and a second voltage and a second level state when the balance is closed;
calculating a voltage difference between the first voltage and the second voltage;
and taking the voltage difference, the first level state and/or the second level state as diagnosis parameters, and substituting the diagnosis parameters into a preset algorithm respectively to obtain the state of the equalization circuit.
8. The method as claimed in claim 7, wherein the step of obtaining the state of the equalizing circuit by using the voltage difference, the first level state and/or the second level state as diagnosis parameters and respectively substituting them into a preset algorithm comprises:
judging whether the voltage difference is smaller than a threshold value;
if the voltage difference is smaller than a threshold value, judging whether the first level state is a high level or not, or whether the second level state is a low level or not;
if the first level state is a high level, judging that the state of the equalizing circuit is open;
and if the second level state is a low level, judging that the state of the equalizing circuit is leakage.
9. The method as claimed in claim 8, wherein the step of determining whether the voltage difference is less than a threshold value comprises:
if the voltage difference is not less than the threshold value, judging whether the first level state and/or the second level state is a low level;
if the first level state is a low level, judging that the state of the equalizing circuit is normally started;
and if the second level state is a high level, judging that the state of the equalizing circuit is normally closed.
10. The method as claimed in claim 8, wherein the threshold value is 50 mv.
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| CN202010129930.2A CN111371139A (en) | 2020-02-28 | 2020-02-28 | State diagnosis circuit and method for equalization circuit |
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| CN202010129930.2A CN111371139A (en) | 2020-02-28 | 2020-02-28 | State diagnosis circuit and method for equalization circuit |
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| CN101795010A (en) * | 2009-12-31 | 2010-08-04 | 惠州市亿能电子有限公司 | Lithium battery protection circuit and protection method thereof |
| CN106240391A (en) * | 2016-08-15 | 2016-12-21 | 惠州市蓝微新源技术有限公司 | A kind of passive equalizing circuit of battery management system |
| CN108226790A (en) * | 2017-11-30 | 2018-06-29 | 宁德时代新能源科技股份有限公司 | Equalization circuit state detection device and method, battery pack and battery management system |
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2020
- 2020-02-28 CN CN202010129930.2A patent/CN111371139A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101795010A (en) * | 2009-12-31 | 2010-08-04 | 惠州市亿能电子有限公司 | Lithium battery protection circuit and protection method thereof |
| CN106240391A (en) * | 2016-08-15 | 2016-12-21 | 惠州市蓝微新源技术有限公司 | A kind of passive equalizing circuit of battery management system |
| CN108226790A (en) * | 2017-11-30 | 2018-06-29 | 宁德时代新能源科技股份有限公司 | Equalization circuit state detection device and method, battery pack and battery management system |
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