CN115967149A - Battery charging and discharging circuit and control method thereof - Google Patents

Battery charging and discharging circuit and control method thereof Download PDF

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Publication number
CN115967149A
CN115967149A CN202211559875.6A CN202211559875A CN115967149A CN 115967149 A CN115967149 A CN 115967149A CN 202211559875 A CN202211559875 A CN 202211559875A CN 115967149 A CN115967149 A CN 115967149A
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voltage
module
charge
charging
main control
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张�雄
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Hubei Eve Power Co Ltd
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Hubei Eve Power Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

The invention provides a battery charging and discharging circuit and a control method thereof. The battery charging and discharging circuit comprises a main control module, a driving module, a charging and discharging switch module, a current acquisition module and a battery. The driving module is used for outputting a first driving voltage and a second driving voltage with adjustable voltage values under the control of the main control module; a first control end included by the charge and discharge switch module is connected to a first driving voltage, and a second control end is connected to a second driving voltage; the current acquisition module is used for acquiring loop current of the battery charging and discharging circuit and feeding the loop current back to the main control module; the main control module is used for acquiring the voltage value of the input end and the voltage value of the output end, and calculating the internal resistance of the charge and discharge switch module according to the voltage value of the input end, the voltage value of the output end and the loop current so as to judge whether the charge and discharge switch module fails or not. The invention can judge whether the charge-discharge switch module is invalid or not and simplify the circuit structure of the battery charge-discharge circuit.

Description

Battery charging and discharging circuit and control method thereof
Technical Field
The invention relates to the technical field of batteries, in particular to a battery charging and discharging circuit and a control method thereof.
Background
In a BMS (BATTERY MANAGEMENT SYSTEM), a BATTERY charging/discharging circuit generally uses a high-power high-voltage MOS Transistor (Metal-Oxide-Semiconductor Field-Effect Transistor) as a charging/discharging switching Transistor, and at the moment of switching of the circuit, a peak voltage generated by a sudden change in current may damage the charging MOS Transistor. If failure diagnosis is not carried out on the charge and discharge switching tube, if the MOS tube fails, the function failure of the charge and discharge circuit of the battery can be caused, and even safety accidents can be caused. In order to extend the lifespan of the BMS and also to consider the safety problem of the battery during the charge and discharge processes, it is necessary to perform failure diagnosis of the charge and discharge switching tube.
However, in the diagnosis scheme of the charge and discharge switch tube on the market at present, a plurality of driving modules are required to be arranged to respectively control different charge and discharge switch tubes, and the circuit structure is complex.
Disclosure of Invention
The embodiment of the invention provides a battery charging and discharging circuit and a control method thereof, wherein whether a charging and discharging switch module fails or not can be judged only by arranging a driving module, and the technical problem of complex circuit structure in the existing diagnosis scheme is solved.
In a first aspect, an embodiment of the present invention provides a battery charging and discharging circuit, including a main control module, a driving module, a charging and discharging switch module, a current collecting module, and a battery;
the driving module is connected to the main control module, and is used for outputting a first driving voltage and a second driving voltage under the control of the main control module, and the voltage value of the first driving voltage and the voltage value of the second driving voltage are both adjustable;
the charging and discharging switch module comprises a first control end, a second control end, an input end and an output end, wherein the first control end is connected to the first driving voltage, the second control end is connected to the second driving voltage, the input end is connected to the anode of the battery, the output end is connected to a first external port of the battery charging and discharging circuit, and the cathode of the battery is connected to a second external port of the battery charging and discharging circuit; the charge and discharge switch module is used for conducting a loop of the battery charge and discharge circuit under the drive of the first drive voltage and the second drive voltage;
the current acquisition module is connected to the main control module and used for acquiring loop current of the battery charging and discharging circuit and feeding the loop current back to the main control module;
the main control module is connected to the input end and the output end respectively, and is used for collecting the voltage value of the input end and the voltage value of the output end, and calculating the internal resistance of the charge and discharge switch module according to the voltage value of the input end, the voltage value of the output end and the loop current so as to judge whether the charge and discharge switch module fails.
In one embodiment, the driving module includes a driving chip, and a first voltage regulating unit and a second voltage regulating unit connected to the driving chip;
the driving chip, the first voltage regulating unit and the second voltage regulating unit are respectively connected to the main control module, and the driving chip is used for outputting a first initial driving voltage and a second initial driving voltage under the control of the main control module; the first voltage regulating unit is used for regulating the first driving voltage based on the first initial driving voltage, and the second voltage regulating unit is used for regulating the second driving voltage based on the second initial driving voltage.
In an embodiment, the first voltage regulating unit and/or the second voltage regulating unit are integrated in the driving chip.
In one embodiment, the current collection module comprises a sampling resistor and a current collection chip;
the sampling resistor is connected in series between the negative electrode of the battery and the second external port, and the current acquisition chip is provided with a first input pin, a second input pin and an output pin; the first input pin is connected to one end of the sampling resistor, the second input pin is connected to the other end of the sampling resistor, and the output pin is connected to the main control module.
In one embodiment, the current collection module further comprises a first resistor and a second resistor;
the first resistor is connected between the first input pin and one end of the sampling resistor in series, and the second resistor is connected between the second input pin and the other end of the sampling resistor in series; the resistance value of the first resistor is equal to the resistance value of the second resistor.
In an embodiment, the charge and discharge switch module includes a discharge switch tube and a charge switch tube, a first pole of the discharge switch tube and a first pole of the charge switch tube are connected to a node, a gate of the discharge switch tube is connected to the first control terminal, and a gate of the charge switch tube is connected to the second control terminal; the second pole of the discharge switch tube is connected to the input end, and the second pole of the charge switch tube is connected to the output end.
In one embodiment, the main control module is further connected to the node to collect a voltage value of the node;
the main control module is used for calculating the internal resistance of the discharge switch tube according to the voltage value of the input end, the voltage value of the node and the loop current so as to judge whether the discharge switch tube fails or not; the main control module is further used for calculating the internal resistance of the charging switch tube according to the voltage value of the output end, the voltage value of the node and the loop current so as to judge whether the charging switch tube fails or not.
In an embodiment, the main control module is further connected to the gate of the discharge switch tube and the gate of the charge switch tube to collect the gate voltage of the discharge switch tube and the gate voltage of the charge switch tube.
In one embodiment, the battery charging and discharging circuit further comprises a controllable fuse connected in series in a loop of the battery charging and discharging circuit;
the main control module is connected with the controllable fuse and is further used for starting the controllable fuse when the charging and discharging switch module is judged to be failed.
In a second aspect, an embodiment of the present invention provides a control method for a battery charging and discharging circuit, which is applied to the battery charging and discharging circuit described in any one of the above items, and includes:
s1, acquiring the first driving voltage and the second driving voltage;
s2, collecting loop current of the battery charging and discharging circuit based on the first driving voltage and the second driving voltage;
s3, collecting the voltage value of the input end and the voltage value of the output end, and calculating the internal resistance of the charge and discharge switch module according to the voltage value of the input end, the voltage value of the output end and the loop current;
and S4, judging whether the charge and discharge switch module fails or not according to the internal resistance.
In an embodiment, step S4 specifically includes:
and judging whether the charge and discharge switch module fails or not according to the internal resistance and the characteristic curve of the charge and discharge switch module.
In an embodiment, before step S4, the method further includes:
s5, adjusting the voltage value of the first driving voltage and the voltage value of the second driving voltage;
repeating steps S2-S3 at least twice;
the step S4 specifically comprises the following steps:
and judging whether the charge and discharge switch module fails or not according to the internal resistance obtained by at least two times of calculation.
The embodiment of the invention has the following beneficial effects:
in the embodiment of the invention, the battery charging and discharging circuit comprises a main control module, a driving module, a charging and discharging switch module, a current collecting module and a battery, the voltage values of the input end and the output end of the charging and discharging switch module are respectively collected through the main control module, the loop current of the battery charging and discharging circuit is collected through the current collecting module, the internal resistance of the charging and discharging switch module can be calculated, and whether the charging and discharging switch module fails or not is judged according to the calculated internal resistance, so that whether the charging and discharging switch module fails or not can be judged in the charging and discharging state of the battery, and the safety and reliability of the battery charging and discharging circuit in the application process are further improved. In the embodiment of the invention, whether the charge and discharge switch module fails can be judged only by arranging the driving module, so that the circuit structure of the battery charge and discharge circuit is simplified.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a battery charging and discharging circuit provided in an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of a battery charging/discharging circuit provided by an embodiment of the present invention;
fig. 3 is a schematic flowchart of a control method of a battery charging/discharging circuit according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a characteristic curve of a MOS transistor according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Furthermore, it should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, and are not intended to limit the present invention.
In the present invention, unless otherwise expressly stated or limited, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, releasably connected, or integral to one another; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.
Referring to fig. 1, a battery charging/discharging circuit 100 is provided according to an embodiment of the present invention. The battery charging and discharging circuit 100 includes a main control module 10, a driving module 20, a charging and discharging switch module 30, a current collecting module 40, and a battery 50.
The driving module 20 is connected to the main control module 10. The driving module 20 is configured to output a first driving voltage V1 and a second driving voltage V2 under the control of the main control module 10. The voltage value of the first driving voltage V1 and the voltage value of the second driving voltage V2 are both adjustable.
The charge and discharge switch module 30 includes a first control terminal C, a second control terminal D, an input terminal a, and an output terminal B. The first control terminal C is connected to the first driving voltage V1. The second control terminal D is connected to the second driving voltage V2. The input terminal a is connected to the positive electrode of the battery 50. The output terminal B is connected to the first external port P of the battery charging and discharging circuit 100 + . The negative electrode of the battery 50 is connected to the second external port P of the battery charge and discharge circuit 100 - . The charge and discharge switch module 30 is configured to operate under the control of the first driving voltage V1 and the second driving voltage V2. The charge and discharge switch module 30 is used for conducting a loop of the battery charge and discharge circuit 100 under the driving of the first driving voltage V1 and the second driving voltage V2.
It should be noted that the input terminal a and the output terminal B of the charge and discharge switch module 30 are relative. When the battery 50 is in two different states of charging and discharging, the input end a and the output end B of the charging and discharging switch module 30 can be interchanged.
The current collection module 40 is connected to the main control module 10. The current collecting module 40 is configured to collect a loop current I of the battery charging and discharging circuit 100, and feed back the loop current I to the main control module 10.
The main control module 10 is connected to the input terminal a and the output terminal B. The main control module 10 is configured to collect a voltage value of the input end a and a voltage value of the output end B, and calculate an internal resistance of the charge and discharge switch module 30 according to the voltage value of the input end a, the voltage value of the output end B, and the loop current I, so as to determine whether the charge and discharge switch module 30 fails.
It can be understood that according to ohm's law, the calculation formula of the internal resistance of the charge and discharge switch module 30 is: r0= (UA-UB)/I.
Wherein r0 represents the internal resistance of the charge and discharge switch module 30, UA represents the voltage value of the input terminal a, and UB represents the voltage value of the output terminal B.
Specifically, in an embodiment, the internal resistance of the charge and discharge switch module 30 may be obtained by calculation only by sampling once; then, the main control module 10 determines whether the charge and discharge switch module 30 is failed according to the calculated internal resistance of the charge and discharge switch module 30 and the characteristic curve of the charge and discharge switch module 30.
The characteristic curve of the charge and discharge switch module 30 may represent a relationship curve between the first driving voltage V1 and the second driving voltage V2 and the internal resistance of the charge and discharge switch module 30. Therefore, on the premise that the voltage values of the first driving voltage V1 and the second driving voltage V2 are determined, whether the internal resistance obtained by sampling calculation is within the normal range can be determined according to the corresponding internal resistance value in the curve, so as to determine whether the charge and discharge switch module 30 is in failure.
It should be noted that the characteristic curve of the charge/discharge switch module 30 can be stored in the main control module 10 or an individual storage unit through a test in advance, which is convenient for the main control module 10 to call.
Of course, in an embodiment, the internal resistances of the charge and discharge switch module 30 may also be obtained by sampling at least twice and calculating. For example, the driving module 20 may adjust the voltage values of the first driving voltage V1 and the second driving voltage V2 under the control of the main control module 10, so as to obtain at least two internal resistances of the charge and discharge switch module 30 through sampling and calculation under the driving of the different first driving voltage V1 and the second driving voltage V2, and then determine whether the charge and discharge switch module 30 fails according to the change conditions of the first driving voltage V1 and the second driving voltage V2 and the change conditions of the two internal resistances. For example, when the charge/discharge switch module 30 is short-circuited, even if the voltage values of the first driving voltage V1 and the second driving voltage V2 are changed, the internal resistance values obtained through multiple calculations are not changed.
In the embodiment of the invention, the main control module 10 is used for respectively acquiring the voltage values of the input end A and the output end B of the charge-discharge switch module 30, and the current acquisition module 40 is used for acquiring the loop current of the battery charge-discharge circuit 100, so that the internal resistance of the charge-discharge switch module 30 can be calculated, and whether the charge-discharge switch module 30 fails or not can be judged according to the calculated internal resistance, therefore, whether the charge-discharge switch module 30 fails or not can be judged in the battery charge-discharge state, and the safety and reliability of the battery charge-discharge circuit 100 in the application process are improved. In the embodiment of the invention, only one driving module 20 is needed to be arranged, so that whether the charge and discharge switch module 30 fails or not can be judged, and the circuit structure of the battery charge and discharge circuit 100 is simplified.
As can be seen from the above, the diagnosis mechanism for determining whether the charge and discharge switch module 30 is failed in the embodiment of the present invention is simple, the diagnosis circuit is simple, the diagnosis time is fast, the diagnosis condition is not limited, and the diagnosis can be completed as long as the battery charge and discharge circuit 100 is powered on and has a certain current.
In one embodiment, the main control module 10 includes, but is not limited to, a single chip, an embedded chip, and the like. For example, the main control module 10 may employ an MCU (Micro-controller Unit).
In one embodiment, the first external port P of the battery charging/discharging circuit 100 + And a second external port P - Can be connected with an external power supply or a load. The battery charging and discharging circuit 100 may charge the battery 50 by an external power source. When the external power supply is interrupted, the battery 50 is in a discharged state to backup power supply to the load.
In an embodiment, the battery 50 may be a storage battery such as a lithium battery capable of charging and discharging, which is not particularly limited in this application.
Referring to fig. 2, in an embodiment, the driving module 20 includes a driving chip 21, and a first voltage regulating unit 22 and a second voltage regulating unit 23 connected to the driving chip 21.
The driving chip 21, the first voltage regulating unit 22 and the second voltage regulating unit 23 are respectively connected to the main control module 10. The driving chip 21 is configured to output a first initial driving voltage Vin1 and a second initial driving voltage Vin2 under the control of the main control module 10. The first voltage regulating unit 22 is configured to regulate the first initial driving voltage Vin1 to a first driving voltage V1 under the control of the main control module 10. The second voltage regulating unit 23 is configured to regulate the second initial driving voltage Vin2 to a second driving voltage V2 under the control of the main control module 10.
It should be noted that, in some embodiments, the first initial driving voltage Vin1 and the second initial driving voltage Vin2 may be the same initial driving voltage.
Specifically, the main control module 10 may output a control signal EN to the driving chip 21, and the driving chip 21 outputs a first initial driving voltage Vin1 and a second initial driving voltage Vin2 under the trigger of the control signal EN. The main control module 10 can also output a first voltage-regulating signal AS1 to the first voltage-regulating unit 22, and output a second voltage-regulating signal AS2 to the second voltage-regulating unit 23. The first voltage regulating unit 22 regulates the first initial driving voltage Vin1 to a first driving voltage V1 under the control of the first voltage regulating signal AS 1. The second voltage regulating unit 23 regulates the second initial driving voltage Vin2 to a second driving voltage V2 under the control of the second voltage regulating signal AS 2.
When the first voltage-regulating signal VS1 and the second voltage-regulating signal VS2 output by the main control module 10 change, the voltage value of the first driving voltage V1 and the voltage value of the second driving voltage V2 may also be changed accordingly.
It should be noted that, when the voltage value of the input terminal a and the voltage value of the output terminal B are collected, the charge and discharge switch module 30 operates under the control of the first driving voltage V1 and the second driving voltage V2, so as to turn on the circuit of the battery charge and discharge circuit 100. After the acquisition is completed, the main control module 10 may adjust the first voltage regulating signal VS1 and the second voltage regulating signal VS2, so that the charge and discharge switch module 30 works under the control of the first initial driving voltage Vin1 and the second initial driving voltage Vin 2; it can also be understood that the first driving voltage V1 is equal to the first initial driving voltage Vin1, and the second driving voltage V2 is equal to the second initial driving voltage Vin2.
In the related art, in order to diagnose whether the charge/discharge switch module 30 fails, a driving chip is usually added to control different charge/discharge switch tubes, which is relatively costly. In the embodiment of the present invention, only one driving chip 21 needs to be provided, and then the driving voltage is adjusted by the first voltage regulating unit 22 and the second voltage regulating unit 23, so that the production cost can be reduced.
In an embodiment, the first voltage regulating unit 22 and the second voltage regulating unit 23 may each include an adjustable resistance, such as a potentiometer. Under the control of the main control module 10, the voltage values of the first driving voltage V1 and the second driving voltage V2 can be adjusted according to the voltage division principle by adjusting the resistance value of the adjustable resistor.
In an embodiment, the first voltage regulating unit 22 and the second voltage regulating unit 23 may each include a single chip or a dedicated DAC (Digital to Analog Converter) chip having a DAC function to regulate the driving voltage output of the driving chip 21.
In an embodiment, the first voltage regulating unit 22 and/or the second voltage regulating unit 23 are integrated within the driving chip 21. That is, the driving chip 21 itself has a function of adjusting the output voltage, thereby further simplifying the circuit structure of the battery charging and discharging circuit 100.
Referring to fig. 2, in an embodiment, the current collecting module 40 includes a sampling resistor R0 and a current collecting chip 41. The sampling resistor R0 is connected in series with the negative electrode of the battery 50 and the second external port P - Between the mouths. The current collection chip 41 has a first input pin 41a, a second input pin 41b, and an output pin 41c. The first input pin 41a is connected to one end of the sampling resistor R0. The second input pin 41b is connected to the other end of the sampling resistor R0. The output pin 41c is connected to the main control module 10.
The resistance value of the sampling resistor R0 is small, the milliohm level is taken as the main value, and the precision is high. Since the resistance of the sampling resistor R0 is very small, it does not substantially affect the original circuit.
The current collection chip 41 may be a chip having an analog-to-digital conversion function. It can be understood that, because the loop current will form a corresponding voltage on the sampling resistor R0, the current in the circuit can be successfully obtained by converting the current into a voltage signal and then quantizing the voltage signal into a corresponding digital signal by using a chip with an analog-to-digital conversion function, thereby completing the sampling process. Of course, in some embodiments, if the sampled voltage needs to be amplified first, the current collecting chip 41 may also be a chip having functions of an operational amplifier and the like, which is not specifically limited in this application.
Further, in some embodiments, the current collection module 40 further includes a first resistor R1 and a second resistor R2. The first resistor R1 is connected in series between one end of the sampling resistor R0 and the first input pin 41 a. The second resistor R2 is connected in series between the other end of the sampling resistor R0 and the second input pin 41 b.
The first resistor R1 and the second resistor R2 play a role in limiting current. The voltage values of the first resistor R1 and the second resistor R2 are equal to avoid influencing sampling precision.
Referring to fig. 2, in an embodiment, the charge/discharge switch module 30 includes a discharge switch Q1 and a charge switch Q2. The first pole of the discharge switch Q1 and the first pole of the charge switch Q2 are connected to a node s. The gate g1 of the discharge switching tube Q1 is connected to a first driving voltage V1. The gate g2 of the charging switch tube Q2 is connected to the second driving voltage V2. The second pole of the discharge switch Q1 is connected to the input terminal a. The second pole of the charging switch Q2 is connected to the output terminal B.
The discharge switching tube Q1 and the charge switching tube Q2 are both N-type MOS tubes, but the application is not limited thereto.
The discharge switch tube Q1 and the charge switch tube Q2 may be connected in series by a common source or in series by a common drain. That is, when the first pole is the source, the second pole is the drain; when the first pole is the drain, the second pole is the source. In the embodiments of the present invention, the first electrode is a source electrode, and the second electrode is a drain electrode, but the present invention is not limited thereto.
A first parasitic diode D1 connected in reverse parallel is integrated between the drain and the source of the discharge switching tube Q1. A second parasitic diode D2 connected in reverse parallel is integrated between the drain and the source of the charging switch tube Q2.
In one embodiment, when the battery charging and discharging circuit 100 is in a charging state or a discharging state, the discharging switch Q1 and the charging switch Q2 are both turned on, so that the power consumption of the circuit can be reduced. At this time, because the discharge switch tube Q1 and the charge switch tube Q2 are connected in series in common source, the voltage value of the first driving voltage V1 is equal to the voltage value of the second driving voltage V2, and it can be ensured that the discharge switch tube Q1 and the charge switch tube Q2 are simultaneously turned on.
In one embodiment, when the battery charging/discharging circuit 100 is in a charging state, the charging switch Q2 and the first parasitic diode D1 are turned on. When the battery charging and discharging circuit 100 is in a discharging state, the discharging switch tube Q1 and the second parasitic diode D2 are turned on.
In the embodiment of the present invention, since the discharge switch Q1 operates under the control of the first driving voltage V1, and the charge switch Q2 operates under the control of the second driving voltage V2, the two are independent of each other. Therefore, when the charging function of the battery charging and discharging circuit 100 is abnormal, the charging switch Q2 can be turned off by the second driving voltage V2, so that the battery 50 is normally discharged. When the discharging function of the battery charging and discharging circuit 100 is abnormal, the discharging switch Q1 can be turned off by the first driving voltage V1, so that the battery 50 is normally charged.
In one embodiment, the main control module 10 is further connected to the node s to collect a voltage value of the node s. The main control module 10 is further configured to calculate an internal resistance of the discharge switching tube Q1 according to the voltage value of the input end a, the voltage value of the node s, and the loop current I, so as to determine whether the discharge switching tube Q1 fails. The main control module 10 is further configured to calculate an internal resistance of the charging switch Q2 according to the voltage value of the output terminal B, the voltage value of the node s, and the loop current I, so as to determine whether the charging switch Q2 is failed.
According to ohm's law, the calculation formula of the internal resistance of the discharge switch tube Q1 is: r1= (Ud 1-Us)/I; the calculation formula of the internal resistance of the charging switch tube Q2 is as follows: r2= (Ud 2-Us)/I.
Wherein r1 represents the internal resistance of the discharge switching tube Q1; ud1 represents the voltage value of the input terminal a (i.e. the drain d1 of the discharge switch tube Q1); ud2 represents the voltage value of the output terminal B (i.e. the drain d2 of the charging switch tube Q2); us represents the voltage value of the node s (i.e., the source of the discharge switch Q1/the charge switch Q2).
In this embodiment, the internal resistance r1 of the discharge switch tube Q1 and the internal resistance r2 of the charge switch tube Q2 can be respectively calculated, so as to respectively determine whether the discharge switch tube Q1 and the charge switch tube Q2 are invalid, thereby further improving the safety performance of the battery charging and discharging circuit 100.
In addition, by collecting the voltage value of the node s, the main control module 10 can also obtain the gate-source voltage of the discharging switch tube Q1 and the gate-source voltage of the charging switch tube Q2, so as to more conveniently judge whether the discharging switch tube Q1 and the charging switch tube Q2 are invalid or not.
In an embodiment, the main control module 10 is further connected to the gate g1 of the discharge switch Q1 and the gate g2 of the charge switch Q2 to collect the gate voltage of the discharge switch Q1 and the gate voltage of the charge switch Q2.
It can be understood that there is a loss in the signal during transmission due to wire resistance and the like. Therefore, the gate voltage output to the discharge switch Q1 and the gate voltage output to the charge switch Q2 may have errors from the ideal voltage. The gate voltage of the discharging switch tube Q1 and the gate voltage of the charging switch tube Q2 are respectively collected by the main control module 10, so that the voltage values of the first driving voltage V1 and the second driving voltage V2 can be better adjusted, and the accuracy of the driving voltage is ensured.
In one embodiment, the battery charging and discharging circuit 100 further includes a controllable fuse 60. The controllable fuse 60 is connected in series in the loop of the battery charging and discharging circuit 100. The controllable fuse 60 is connected to the main control module 10. The main control module 10 is further configured to open the controllable fuse 60 when it is determined that the charge and discharge switch module 30 is failed. Specifically, the controllable fuse 60 may be disposed at the output terminal B and the first external port P + In the meantime.
The controllable fuse 60 may be a controllable fuse, and when the main control module 10 determines that the charge/discharge switch module 30 is failed, it may send a fusing instruction to the controllable fuse, so that the controllable fuse is fused by itself, thereby protecting an external power supply or a load and improving safety.
In a second aspect, an embodiment of the present invention further provides a method for controlling a battery charging/discharging circuit, which is applied to the battery charging/discharging circuit 100 according to any of the above embodiments. Specifically, referring to fig. 2 and 3, the method for controlling the battery charging/discharging circuit includes the following steps:
s1, acquiring the first driving voltage and the second driving voltage.
Specifically, the driving module 20 outputs a first driving voltage V1 and a second driving voltage V2 under the control of the main control module 10. Therefore, the main control module 10 may obtain the voltage values of the first driving voltage V1 and the second driving voltage V2 according to the internal instruction. The charge and discharge switch module 30 operates under the control of the first driving voltage V1 and the second driving voltage V2 to turn on the circuit of the battery charge and discharge circuit 100. The battery charging and discharging circuit 100 charges the battery 50 or supplies power to a load.
And S2, acquiring loop current of the battery charging and discharging circuit based on the first driving voltage V1 and the second driving voltage V2.
Specifically, when the battery charging and discharging circuit 100 works, the current collecting module 40 collects the loop current I and feeds the loop current I back to the main control module 10.
And S3, acquiring the voltage value of the input end and the voltage value of the output end, and calculating the internal resistance of the charge-discharge switch module according to the voltage value of the input end, the voltage value of the output end and the loop current.
Specifically, the main control module 10 is connected to the input end a and the output end B. The voltage value of the input end A and the voltage value of the output end B are acquired by utilizing the acquisition function of the main control module 10, so that the circuit structure can be simplified. Then, the main control module 10 calculates the internal resistance of the charge and discharge switch module 30 according to the voltage value of the input terminal a, the voltage value of the output terminal B, and the loop current I.
The calculation formula of the internal resistance of the charge and discharge switch module 30 is: r0= (UA-UB)/I. r0 represents the internal resistance of the charge and discharge switch module 30, UA represents the voltage value of the input terminal a, and UB represents the voltage value of the output terminal B.
And S4, judging whether the charge and discharge switch module fails or not according to the internal resistance.
Specifically, in an embodiment, the step S4 specifically includes: and judging whether the charge and discharge switch module fails or not according to the internal resistance and the characteristic curve of the charge and discharge switch module.
In this embodiment, the internal resistance of the charge and discharge switch module 30 may be obtained by calculation only by sampling once; then, the main control module 10 determines whether the charge and discharge switch module 30 fails according to the calculated internal resistance and the characteristic curve of the charge and discharge switch module 30.
For example, the charge/discharge switch module 30 includes a discharge switch Q1 and a charge switch Q2. The characteristic curve of the charge/discharge switch module 30 may be a relationship curve between the gate-source voltage and the internal resistance (i.e., the resistance between the source and the drain) of the discharge switch Q1 (the charge switch Q2). For example, as shown in fig. 4, under a loop current I, the larger the gate-source voltage of the MOS transistor is, the smaller the internal resistance of the MOS transistor is. At different loop currents I (I =500mA or I =50 mA), the relationship between the gate-source voltage and the internal resistance is also different.
Since the gate g1 of the discharge switch tube Q1 is connected to the first driving voltage V1, the gate g2 of the charge switch tube Q2 is connected to the second driving voltage V2, and the discharge switch tube Q1 is connected to the common source of the charge switch tube Q2, on the premise that the voltage values of the first driving voltage V1 and the second driving voltage V2 are determined, whether the internal resistance obtained by sampling calculation is within a normal range can be judged according to the internal resistance in the curve, so as to judge whether the charge-discharge switch module 30 fails.
It should be noted that the characteristic curve of the charge/discharge switch module 30 can be stored in the main control module 10 or an individual storage unit through a test in advance, which is convenient for the main control module 10 to call.
In an embodiment, the following steps are further included between step S3 and step S4:
s5, adjusting the voltage value of the first driving voltage and the voltage value of the second driving voltage;
specifically, the main control module 10 controls the driving module 20 to adjust the voltage value of the first driving voltage V1 and the voltage value of the second driving voltage V2.
For example, in the first sampling, the voltage value of the first driving voltage V1 is 4V, and the voltage value of the second driving voltage V2 is 10V.
During the second sampling, the voltage value of the first driving voltage V1 may be kept unchanged, and the voltage value of the second driving voltage V2 may be adjusted; or, keeping the voltage value of the second driving voltage V2 unchanged, and adjusting the voltage value of the first driving voltage V1; or the voltage value of the first driving voltage V1 and the voltage value of the second driving voltage V2 are decreased or increased at the same time.
Repeating steps S2-S3 at least twice;
specifically, the steps S2 to S3 are repeated, and different internal resistances of the charge and discharge switch module 30 are obtained by sampling under the driving of different first driving voltages V1 and second driving voltages V2.
Further, when sampling is performed multiple times, step S4 specifically includes: and the main control module judges whether the charge and discharge switch module fails according to the internal resistance obtained by at least two times of calculation.
It can be understood that, as shown in fig. 4, the larger the gate-source voltage of the MOS transistor is, the smaller the internal resistance of the MOS transistor is under the same loop current I. Therefore, the internal resistance calculated by adjusting the voltage value of the first driving voltage V1 and the voltage value of the second driving voltage V2 in step S5 should change regularly, and if the internal resistances calculated many times have little difference or change greatly, it indicates that the discharging switch Q1 and/or the charging switch Q2 in the charging and discharging switch module 30 are/is disabled.
In an embodiment, step S3 further includes: collecting a voltage value of a node s, and calculating an internal resistance r1 of a discharge switch tube Q1 according to the voltage value of an input end A, the voltage value of the node s and a loop current I; and calculating the internal resistance r2 of the charging switch tube Q2 according to the voltage value of the output end B, the voltage value of the node s and the loop current I.
Specifically, the calculation formula of the internal resistance of the discharge switch tube Q1 is as follows: r1= (Ud 1-Us)/I; the calculation formula of the internal resistance of the charging switch tube Q2 is as follows: r2= (Ud 2-Us)/I.
In this embodiment, the internal resistance r1 of the discharge switch tube Q1 and the internal resistance r2 of the charge switch tube Q2 may be respectively calculated, so as to respectively determine whether the discharge switch tube Q1 and the charge switch tube Q2 are invalid, and further improve the safety performance of the battery charging and discharging circuit 100.
In one embodiment, before step S1, it is also necessary to detect the power supply current of the BMS, and detect other operating states of the BMS, so as to prevent the battery 50 from being overcharged and overdischarged (abnormal operating states such as overvoltage or undervoltage), and ensure the normal operation of the whole board.
The above embodiments of the present invention are described in detail, and the principle and the implementation of the present invention are explained by applying specific embodiments, and the description of the above embodiments is only used to help understanding the method of the present invention and the core idea thereof; meanwhile, for those skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims (12)

1. A battery charging and discharging circuit is characterized by comprising a main control module, a driving module, a charging and discharging switch module, a current acquisition module and a battery;
the driving module is connected to the main control module, and is used for outputting a first driving voltage and a second driving voltage under the control of the main control module, and the voltage value of the first driving voltage and the voltage value of the second driving voltage are both adjustable;
the charging and discharging switch module comprises a first control end, a second control end, an input end and an output end, wherein the first control end is connected to the first driving voltage, the second control end is connected to the second driving voltage, the input end is connected to the anode of the battery, the output end is connected to a first external port of the battery charging and discharging circuit, and the cathode of the battery is connected to a second external port of the battery charging and discharging circuit; the charge and discharge switch module is used for conducting a loop of the battery charge and discharge circuit under the drive of the first drive voltage and the second drive voltage;
the current acquisition module is connected to the main control module and used for acquiring loop current of the battery charging and discharging circuit and feeding the loop current back to the main control module;
the main control module is connected to the input end and the output end respectively, and is used for collecting the voltage value of the input end and the voltage value of the output end, and calculating the internal resistance of the charge and discharge switch module according to the voltage value of the input end, the voltage value of the output end and the loop current so as to judge whether the charge and discharge switch module fails.
2. The battery charging and discharging circuit according to claim 1, wherein the driving module comprises a driving chip and a first voltage regulating unit and a second voltage regulating unit connected to the driving chip;
the driving chip, the first voltage regulating unit and the second voltage regulating unit are respectively connected to the main control module, and the driving chip is used for outputting a first initial driving voltage and a second initial driving voltage under the control of the main control module; the first voltage regulating unit is used for regulating the first driving voltage based on the first initial driving voltage, and the second voltage regulating unit is used for regulating the second driving voltage based on the second initial driving voltage.
3. The battery charging and discharging circuit according to claim 2, wherein the first voltage regulating unit and/or the second voltage regulating unit are integrated in the driving chip.
4. The battery charging and discharging circuit according to any one of claims 1 to 3, wherein the current collecting module comprises a sampling resistor and a current collecting chip;
the sampling resistor is connected in series between the negative electrode of the battery and the second external port, and the current acquisition chip is provided with a first input pin, a second input pin and an output pin; the first input pin is connected to one end of the sampling resistor, the second input pin is connected to the other end of the sampling resistor, and the output pin is connected to the main control module.
5. The battery charging and discharging circuit according to claim 4, wherein the current collection module further comprises a first resistor and a second resistor;
the first resistor is connected between the first input pin and one end of the sampling resistor in series, and the second resistor is connected between the second input pin and the other end of the sampling resistor in series; the resistance value of the first resistor is equal to the resistance value of the second resistor.
6. The battery charging and discharging circuit according to any one of claims 1 to 3, wherein the charging and discharging switch module comprises a discharging switch tube and a charging switch tube, a first pole of the discharging switch tube and a first pole of the charging switch tube are connected to a node, a gate of the discharging switch tube is connected to the first control terminal, and a gate of the charging switch tube is connected to the second control terminal; the second pole of the discharge switch tube is connected to the input end, and the second pole of the charge switch tube is connected to the output end.
7. The battery charging and discharging circuit according to claim 6, wherein the main control module is further connected to the node to collect a voltage value of the node;
the main control module is used for calculating the internal resistance of the discharge switch tube according to the voltage value of the input end, the voltage value of the node and the loop current so as to judge whether the discharge switch tube fails or not; the main control module is further used for calculating the internal resistance of the charging switch tube according to the voltage value of the output end, the voltage value of the node and the loop current so as to judge whether the charging switch tube fails or not.
8. The battery charging and discharging circuit according to claim 6, wherein the main control module is further connected to the gate of the discharging switch tube and the gate of the charging switch tube to collect the gate voltage of the discharging switch tube and the gate voltage of the charging switch tube.
9. A battery charging and discharging circuit according to any one of claims 1 to 3, further comprising a controllable fuse connected in series in the loop of the battery charging and discharging circuit;
the main control module is connected with the controllable fuse and is further used for starting the controllable fuse when the charging and discharging switch module is judged to be invalid.
10. A control method of a battery charging and discharging circuit applied to the battery charging and discharging circuit according to any one of claims 1 to 9, comprising:
s1, acquiring the first driving voltage and the second driving voltage;
s2, collecting loop current of the battery charging and discharging circuit based on the first driving voltage and the second driving voltage;
s3, collecting the voltage value of the input end and the voltage value of the output end, and calculating the internal resistance of the charge and discharge switch module according to the voltage value of the input end, the voltage value of the output end and the loop current;
and S4, judging whether the charging and discharging switch module fails according to the internal resistance.
11. The method for controlling the battery charging and discharging circuit according to claim 10, wherein the step S4 is specifically:
and judging whether the charge and discharge switch module fails or not according to the internal resistance and the characteristic curve of the charge and discharge switch module.
12. The method for controlling the battery charging and discharging circuit according to claim 10, further comprising, between step S3 and step S4:
s5, adjusting the voltage value of the first driving voltage and the voltage value of the second driving voltage;
repeating steps S2-S3 at least twice;
the step S4 specifically comprises the following steps:
and judging whether the charge and discharge switch module fails or not according to the internal resistance obtained by at least two times of calculation.
CN202211559875.6A 2022-12-06 2022-12-06 Battery charging and discharging circuit and control method thereof Pending CN115967149A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211559875.6A CN115967149A (en) 2022-12-06 2022-12-06 Battery charging and discharging circuit and control method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211559875.6A CN115967149A (en) 2022-12-06 2022-12-06 Battery charging and discharging circuit and control method thereof

Publications (1)

Publication Number Publication Date
CN115967149A true CN115967149A (en) 2023-04-14

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211559875.6A Pending CN115967149A (en) 2022-12-06 2022-12-06 Battery charging and discharging circuit and control method thereof

Country Status (1)

Country Link
CN (1) CN115967149A (en)

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