A charge and discharge protection circuit for multi-section batteries

Abstract

The present invention relates to a charge-discharge protection circuit for multiple batteries. The charge-discharge protection circuit includes batteries, a processing device, a power transistor, and a control transistor. The multiple batteries are connected in series, each connected to the processing device via a corresponding power transistor. The processing device is configured to control the power transistor on or off based on battery charge / discharge status data. The processing device is also connected to the control transistor, which is configured to control the on / off state of the charge or discharge path of the charge-discharge protection circuit. The charge-discharge protection circuit of the present invention utilizes an internal battery level contact detection method. When one or more batteries exhibit an abnormality, the circuit can accurately and promptly determine the battery's status and immediately issue an alarm signal, thereby disconnecting or short-circuiting the corresponding battery to enable the protection circuit to continue operating.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a charge and discharge protection circuit for multiple batteries. Background Art

[0002] With the rapid development of smart homes and the Internet of Things, there are more and more occasions for mobile power supply, such as smart robot series equipment, drone series equipment, etc. These devices are equipped with multi-cell batteries for power supply, which provide sufficient energy for various application devices; in addition, there are also mobile power supply devices in currently popular power tools, such as electric bicycles equipped with mobile power supplies, which all use multi-cell batteries.

[0003] However, the core technology of the matching battery protection circuit is in the hands of TI and a few foreign companies. The multi-cell battery protection circuits developed by several domestic companies only focus on charging detection, overcharge and over-discharge detection, but do not provide protection for abnormalities in the series-connected batteries. When an abnormality occurs in the multi-cell batteries in series, such as poor contact of one of the batteries due to external reasons, the series path will be disconnected and the power supply to the entire system will be cut off; if it is a drone, it will crash; if it is an electric car, it will experience an instantaneous cut-off phenomenon, posing a very great danger to the user. Summary of the Invention

[0004] In view of this, the present invention provides a charge and discharge protection circuit for multiple batteries. The charge and discharge protection circuit uses internal battery level contact detection to promptly determine the status of the battery itself and the contact status with the multiple battery protection system, thereby making a timely emergency response so that the protection circuit can continue to work. At the same time, it can also issue an alarm signal for the user to make timely corrections.

[0005] The technical solution of the present invention is:

[0006] An embodiment of the present invention provides a charge and discharge protection circuit for multiple batteries, the charge and discharge protection circuit including a battery, a processing device, a power tube, and a control tube;

[0007] Wherein, a plurality of the batteries are connected in series, and each battery is connected to a processing device via a corresponding power tube, and the processing device is used to control the opening or closing of the power tube according to the charge / discharge status data of the battery;

[0008] The processing device is also connected to a control tube, which is used to control the on and off of the charging or discharging path of the charge and discharge protection circuit.

[0009] Furthermore, the processing device includes a voltage control device and a level analysis device;

[0010] The voltage control device is used to detect the charge / discharge status data of each battery to determine whether the battery is abnormal;

[0011] The level analysis device is connected to the voltage control device and the power tube respectively, and is used to control the output signal of the voltage control device through the power tube.

[0012] Furthermore, when the battery is in charging mode:

[0013] If one of the batteries is abnormal, the voltage control device controls the power tube corresponding to the battery to turn on, while continuing to charge the other batteries.

[0014] Furthermore, when the battery is in charging mode:

[0015] If the initial voltage of one of the batteries during charging is greater than the initial voltage of the other batteries during charging, the voltage control device turns on the power tube corresponding to the battery and short-circuits the battery;

[0016] If the level of one of the batteries does not increase within a preset time range, the voltage control device determines that the battery is a dead battery, and then the voltage control device turns on the power tube corresponding to the battery and sends a determination signal to the level analysis device through the power tube.

[0017] Furthermore, the processing device is also used to detect the voltage across each battery and calculate the difference between the voltages across each battery. If the difference is higher than a preset voltage threshold, it is determined that the batteries are different types of batteries.

[0018] Furthermore, the processing device is also used to detect the voltage across each battery and calculate the difference between the voltages across each battery. If the difference between the voltages across each battery is less than a preset difference threshold, the processing device determines that the battery is in charging mode.

[0019] Furthermore, the protection circuit also includes a resistor, which is connected to the battery and the control tube respectively, and the resistor is used to sample the current in the protection circuit.

[0020] Furthermore, when the battery is in discharge mode:

[0021] When the current sampled by the resistor exceeds a preset current threshold, the processing device starts overcurrent protection and closes the discharge path of the protection circuit.

[0022] Furthermore, when the battery is in discharge mode:

[0023] If the voltage control device detects that the voltage of the battery has reached a preset voltage threshold, the control tube shuts off the discharge path of the protection circuit;

[0024] If the voltage of one of the batteries reaches a preset voltage threshold after discharge, and the voltages of the other batteries are higher than the preset voltage threshold, the voltage control device turns on the power tube and short-circuits the path of the battery;

[0025] If one of the batteries is abnormal, the voltage control device turns on the power tube and short-circuits the path of the battery.

[0026] Furthermore, the voltage control device includes a comparator and a level processor;

[0027] The comparator is connected to the battery and a pin of the processing device, and is used to compare the level value of the pin of the processing device with the reference voltage;

[0028] The level processor is used to compare the level values between different pins of the processing device and send the comparison result to the level analysis device.

[0029] A charge and discharge protection circuit for multiple batteries of the present invention adopts an internal battery level contact detection method. When an abnormality occurs in one or more batteries, the status of the battery itself and the contact status between the battery and the protection system can be accurately and timely determined. The multiple battery protection circuit can immediately make an emergency response, such as disconnecting the corresponding battery or short-circuiting it to enable the protection circuit to continue working; and an alarm signal is sent to an external MCU control module through a level analysis device to facilitate timely maintenance and processing by the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a charge and discharge protection circuit for multiple batteries provided according to an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of the structure of a processing device provided in an embodiment of the present invention;

[0032] Figure 3 A circuit diagram of a first voltage control device provided by an embodiment of the present invention;

[0033] Figure 4 A circuit diagram of a control tube provided in an embodiment of the present invention.

[0034] Among them, the processing device 100, the first voltage control device 110, the second voltage control device 120, the third voltage control device 130, the level analysis device 140; the first comparator 111; the second comparator 112

[0035] First battery 210, second battery 220, third battery 230;

[0036] First power tube-N1, second power tube-N2, third power tube-N3, fourth power tube-N4, fifth power tube-N5;

[0037] Resistor - 300, control tube - 400. DETAILED DESCRIPTION

[0038] The present invention is described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in this field based on these embodiments are all within the scope of protection of the present invention.

[0039] Certain words are used in this specification and claims to refer to specific components, and those with ordinary knowledge in the field should be understandable. Hardware manufacturers may use different terms to refer to the same component. This specification and the scope of subsequent patent applications do not use the difference in name as a way to distinguish components, but rather use the difference in function of the components as the criterion for distinction. The word "including" mentioned throughout the specification and claims is an open-ended term and should be interpreted as "including but not limited to". In addition, the word "coupled" here includes any direct and indirect electrical connection means. Therefore, if the text describes a first circuit coupled to a second circuit, it means that the first circuit can be directly electrically connected to the second circuit, or indirectly connected to the second circuit through other components such as resistors, etc.

[0040] This embodiment provides a charge and discharge protection circuit for multiple batteries, the charge and discharge protection circuit including a battery, a processing device, a power tube, and a control tube;

[0041] Wherein, a plurality of the batteries are connected in series, and each battery is connected to a processing device via a corresponding power tube, and the processing device is used to control the opening or closing of the power tube according to the charge / discharge status data of the battery;

[0042] The processing device is also connected to a control tube, which is used to control the on and off of the charging or discharging path of the charge and discharge protection circuit.

[0043] For details, see Figure 1 , Figure 1This is a schematic structural diagram of a charge and discharge protection circuit for a multi-cell battery according to an embodiment of the present invention. The multi-cell battery protection circuit includes a processing device 100, a first battery 210, a second battery 220, a third battery 230, a first power transistor N1, a second power transistor N2, a third power transistor N3, a resistor 300, and a control transistor 400.

[0044] Wherein, the first battery 210, the second battery 220 and the third battery 230 are connected in series;

[0045] The positive electrode of the first battery 210 is connected to the source electrode of the first power transistor N1 and the first pin of the processing device 100 respectively; the first battery 210 is also connected to the first external input terminal P1, and the first external input terminal P1 is connected to the external load;

[0046] The negative electrode of the first battery 210 is connected to the drain of the first power transistor N1, the second and third pins of the processing device 100, and the source of the second power transistor N2 respectively;

[0047] The positive electrode of the second battery 220 is connected to the drain of the first power transistor N1, the source of the second power transistor N2, and the third pin of the processing device 100 respectively;

[0048] The negative electrode of the second battery 220 is connected to the drain of the second power transistor N2, the fourth and fifth pins of the processing device 100, and the source of the third power transistor 330 respectively;

[0049] The positive electrode of the third battery 230 is connected to the drain of the second power transistor N2, the source of the third power transistor N3, and the fifth pin of the processing device 100 respectively;

[0050] The negative electrode of the third battery 230 is connected to the drain of the third power transistor N3, the sixth and seventh pins of the processing device 100, and one end of the resistor 300 respectively;

[0051] The other end of the resistor 300 is connected to the input end of the control tube 400; the first output end of the control tube 400 is connected to the processing device 100, and the second output end of the control tube 400 is connected to the second external input end P2, and the second external input end P2 is connected to the external load; the control tube 400 is used to control the on / off of the charging or discharging path of the multi-cell battery protection circuit.

[0052] For further information, see Figure 2 , Figure 2 This is a structural diagram of a processing device provided in an embodiment of the present invention. The processing device 100 includes a first voltage control device 110, a second voltage control device 120, a third voltage control device 130 and a level analysis device 140;

[0053] The first input terminal of the first voltage control device 110 is connected to the positive electrode of the first battery 210, the second input terminal of the first voltage control device 110 is connected to the negative electrode of the first battery 210, and the output terminal of the first voltage control device 110 is connected to the first input terminal of the level analysis device 140. The first voltage control device 110 is used to detect charge / discharge status data of the first battery 210, including overvoltage detection data, undervoltage detection data, charging speed, and discharging speed of the first battery 210, to determine whether the first battery 210 is abnormal.

[0054] A first input terminal of the second voltage control device 120 is connected to the positive electrode of the second battery 220, a second input terminal of the second voltage control device 120 is connected to the negative electrode of the second battery 220, and an output terminal of the second voltage control device 120 is connected to the second input terminal of the level analysis device 140. The second voltage control device 120 is used to detect charge / discharge status data of the second battery 220, including overvoltage detection data, undervoltage detection data, charging speed, and discharging speed of the second battery 220, so as to determine whether the second battery 220 is damaged.

[0055] The first input terminal of the third voltage control device 130 is connected to the positive electrode of the third battery 230, the second input terminal of the third voltage control device 130 is connected to the negative electrode of the third battery 230, and the output terminal of the third voltage control device 130 is connected to the third input terminal of the level analysis device 140; the third voltage control device 130 is used to detect the charge / discharge status data of the third battery 230, and the charge / discharge status data of the third battery 230 includes the overvoltage detection data, undervoltage detection data, charging speed, and discharging speed of the third battery 230, so as to determine whether the second battery 220 is damaged. ; The first output end of the level analysis device 140 is connected to the gate of the first power tube N1, the second output end of the level analysis device 140 is connected to the gate of the second power tube N2, and the third output end of the level analysis device 140 is connected to the gate of the third power tube N3; the level analysis device 140 is used to control the output signals of the first voltage control device 110, the second voltage control device 120 and the third voltage control device 130; further, the level analysis device 140 also generates an alarm signal and transmits the alarm signal to the external MCU control module, and the MCU control module issues the alarm signal.

[0056] Among them, the level analysis device 140 includes an analog comparator and a digital gate circuit, the analog comparator is connected to the digital gate circuit, the digital gate circuit includes an AND gate, an OR gate and an inverter, the analog comparator is a CMOS or bipolar comparator commonly used in the prior art, and the specific device connection of the level analysis device 140 is the prior art and will not be repeated here; the model of the level analysis device 140 can be yd3358.

[0057] For further information, see Figure 3 , Figure 3 A circuit diagram of a first voltage control device provided in an embodiment of the present invention; the first voltage control device 110 includes a first comparator 111, a second comparator 112 and a level processor 113, where the level processor 113 includes an analog comparator and a digital gate circuit, the analog comparator is connected to the digital gate circuit, the digital gate circuit includes an AND gate, an OR gate and an inverter, the analog comparator is a CMOS or bipolar comparator commonly used in the prior art, and the specific device connection of the level processor 113 is prior art and will not be repeated here.

[0058] The first input terminal of the first comparator 111 is connected to the first pin A of the processing device 100, the second input terminal of the first comparator 111 is connected to the positive electrode of the first battery 210, and the output terminal of the first comparator 111 is connected to the level processor 113; the first comparator 111 is used to compare the first pin A of the processing device 100 with the reference voltage V A The level value of

[0059] The first input terminal of the second comparator 112 is connected to the second pin B of the processing device 100, the second input terminal of the second comparator 112 is connected to the positive electrode of the second battery 220, and the output terminal of the second comparator 112 is connected to the level processor 113. The second comparator 112 is used to compare the second pin B of the processing device 100 with the reference voltage V B The level value of

[0060] The level processor 113 is used to compare the levels of the first pin A and the second pin B of the processing device, and send the comparison result to the level analysis device 140 .

[0061] Furthermore, the control tube 400 may be an NMOS power tube or a PMOS power tube, or may be a plurality of NMOS power tubes connected in series or a plurality of PMOS power tubes connected in series;

[0062] Preferably, see Figure 4 , Figure 4This is a circuit diagram of a control tube provided by an embodiment of the present invention. The control tube 500 includes a fourth power tube N4 and a fifth power tube N5 connected in series. Both the fourth power tube N4 and the fifth power tube N5 can be NMOS power tubes.

[0063] The battery in this embodiment may be a lithium battery, or other types of batteries, such as a nickel-cadmium battery or a nickel-metal hydride battery, which is not limited here.

[0064] The working status of the batteries in the multi-cell battery protection circuit of this embodiment during charging is as follows:

[0065] Before charging, the voltages of the first battery 210, the second battery 220, and the third battery 230 connected in series are first tested. If the difference between the voltages of the first battery 210, the second battery 220, and the third battery 230 is less than (for example, a preset difference threshold of 200 mV), the first battery 210, the second battery 220, and the third battery 230 enter the normal charging mode.

[0066] After a fixed delay of the digital delay module inside the level processor, the first battery 210, the second battery 220, and the third battery 230 connected in series are retested. If the difference between the voltage across one battery and the voltage across the other batteries is greater than 500mV, it is determined that the first battery 210, the second battery 220, and the third battery 230 are different types of batteries. The O1, O2, and O3 terminals of the multi-cell battery protection circuit output an alarm signal to prompt the user to replace the battery.

[0067] When the first battery 210, the second battery 220, and the third battery 230 of the multi-cell battery protection circuit are charged normally, the first voltage control device 110 detects the charging status data of the first battery 210, the second voltage control device 120 detects the charging status data of the second battery 220, and the third voltage control device 130 detects the status of the charging process (trickle current, constant current, constant voltage) of the third battery 230.

[0068] When one of the batteries experiences an abnormality, for example, if the contact of the first battery 210 is disconnected, the first voltage control device 110 controls the first power transistor N1 to turn on and continue charging the second battery 220 and the third battery 230, and the level analysis device 140 outputs an alarm signal from the O1 terminal. Similarly, if the contact of the second battery 220 is disconnected, the level analysis device 140 outputs an alarm signal from the O2 terminal; if the contact of the third battery 230 is disconnected, the level analysis device 140 outputs an alarm signal from the O3 terminal.

[0069] When the initial voltage of one of the batteries during charging is greater than the voltages of the remaining batteries, for example, when the initial voltage of the first battery 210 during charging is greater than the initial voltages of the second battery 220 and the third battery 230 during charging, the first battery 210, the second battery 220, and the third battery 230 begin to charge normally. As the charging time increases, the voltages of the first battery 210, the second battery 220, and the third battery 230 all increase. When the first battery 210 is fully charged, the second battery 220 and the third battery 230 have not yet completed charging. In this embodiment, the first voltage control device turns on the first power tube N1 and short-circuits the first battery 210 to ensure that the second battery 220 and the third battery 230 can continue to charge.

[0070] When one of the batteries is charging, for example, the first battery 210, the level of the battery does not increase. The first voltage control device 110 determines that the first battery 210 is a dead battery. The voltage control device then turns on the power transistor corresponding to the battery and sends a determination signal to the level analysis device 140 via the first power transistor N1. The level analysis device 140 then outputs an alarm signal via the O1 terminal. The second battery 220 and the third battery 230 can continue to charge.

[0071] When the first battery 210 and the second battery 220 are charging, the voltage levels of the first battery 210 and the second battery 220 never increase. The first voltage control device 110 determines that the first battery 210 is a dead battery and sends a determination signal to the level analysis device 140 through the first power tube N1. The second voltage control device 120 determines that the second battery 220 is a dead battery and sends a determination signal to the level analysis device 140 through the second power tube N2. The level analysis device 140 outputs an alarm signal through the O1 terminal, and the third battery 230 can continue to charge.

[0072] The working states of the batteries in the multi-cell battery protection circuit during charging are merely examples, and the batteries used in the examples may be any one or more batteries in the multi-cell battery protection circuit.

[0073] The working state of the batteries in the multi-cell battery protection circuit of this embodiment during discharge is as follows:

[0074] When the first battery 210, the second battery 220, and the third battery 230 of the multi-cell battery protection circuit are discharging normally, the three batteries discharge at the same rate. The first voltage control device 110 detects the discharge status data of the first battery 210, the second voltage control device 120 detects the discharge status data of the second battery 220, and the third voltage control device 130 detects the discharge status data of the third battery 230. When it is detected that the voltages of the first battery 210, the second battery 220, and the third battery 230 are at a preset voltage threshold (for example, the preset voltage threshold is 2.8V), the control tube 400 shuts off the discharge circuit of the multi-cell battery protection circuit.

[0075] When a short circuit occurs in the external load connected to the first battery 210, the second battery 220, and the third battery 230 connected in series, the resistor 300 samples the current in the multi-cell battery protection circuit. When the sampled current exceeds a preset current threshold, the overcurrent protection is activated and the discharge path is shut down.

[0076] When the voltage of one of the batteries after discharge reaches a preset voltage threshold (for example, the preset voltage threshold is 2.8V), for example, after the first battery 210 is discharged, the first voltage control device 110 detects that the voltage of the first battery 210 reaches 2.8V, and the second voltage control device 120 detects that the voltage of the second battery 220 is higher than 2.8V, and the third voltage control device 130 detects that the voltage of the third battery 230 is higher than 2.8V, the first voltage control device 110 turns on the first power transistor N1 and short-circuits the path of the first battery 210 to ensure that the second battery 220 and the third battery 230 can discharge normally;

[0077] When one of the batteries is abnormal, for example, the first battery 210 is disconnected, the first voltage control device 110 turns on the first power transistor N1 and short-circuits the path of the first battery 210 to ensure that the second battery 220 and the third battery 230 can discharge normally.

[0078] The working states of the batteries in the multi-cell battery protection circuit during discharge are merely examples, and the batteries used in the examples may be any one or more batteries in the multi-cell battery protection circuit.

[0079] Beneficial effects of the present invention:

[0080] The charge and discharge protection circuit for multiple batteries of the present invention adopts an internal battery level contact detection method. When one or more batteries have an abnormality, the battery status itself and the contact status between the battery and the protection system can be accurately and timely determined. The multi-cell battery protection circuit can immediately make an emergency response, such as disconnecting the corresponding battery or short-circuiting it to enable the protection circuit to continue working; and an alarm signal is sent to the external MCU control module through the level analysis device to facilitate timely maintenance and processing by the user.

[0081] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the embodiments of the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0082] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A charge and discharge protection circuit for multiple batteries, characterized by: The charge and discharge protection circuit includes a battery, a processing device, a power tube and a control tube; Wherein, a plurality of the batteries are connected in series, and each battery is connected to a processing device via a corresponding power tube, and the processing device is used to control the opening or closing of the power tube according to the charge / discharge status data of the battery; The processing device is also connected to a control tube, which is used to control the on / off of the charging or discharging path of the charge-discharge protection circuit; The processing device includes a voltage control device and a level analysis device; The voltage control device is used to detect the charge / discharge status data of each battery to determine whether the battery is abnormal; The level analysis device is connected to the voltage control device and the power tube respectively, and is used to control the output signal of the voltage control device through the power tube; While the battery in question is in charging mode: If one of the batteries is abnormal, the voltage control device controls the power tube corresponding to the battery to turn on, while continuing to charge the other batteries; While the battery in question is in charging mode: If the initial voltage of one of the batteries during charging is greater than the initial voltage of the other batteries during charging, the voltage control device turns on the power tube corresponding to the battery and short-circuits the battery; If the level of one of the batteries does not increase within a preset time range, the voltage control device determines that the battery is a dead battery, and the voltage control device turns on the power tube corresponding to the battery and sends a determination signal to the level analysis device through the power tube; While the battery is in discharge mode: If the voltage control device detects that the voltage of the battery has reached a preset voltage threshold, the control tube shuts off the discharge path of the protection circuit; If the voltage of one of the batteries reaches a preset voltage threshold after discharge, and the voltages of the other batteries are higher than the preset voltage threshold, the voltage control device turns on the power tube and short-circuits the path of the battery; If one of the batteries is abnormal, the voltage control device turns on the power tube and short-circuits the path of the battery; The processing device is further configured to detect the voltage across each battery and calculate the difference between the voltages across the batteries. If the difference is higher than a preset voltage threshold, the batteries are determined to be different types. The processing device is further configured to detect the voltage across each battery and calculate the difference between the voltages across the batteries. If the difference between the voltages across the batteries is less than a preset difference threshold, the processing device determines that the battery is in charging mode.

2. The charge and discharge protection circuit according to claim 1, characterized in that: The protection circuit further includes a resistor, which is connected to the battery and the control tube respectively, and is used to sample the current in the protection circuit.

3. The charge and discharge protection circuit according to claim 2, characterized in that: While the battery is in discharge mode: When the current sampled by the resistor exceeds a preset current threshold, the processing device starts overcurrent protection and closes the discharge path of the protection circuit.

4. The protection circuit according to claim 1, wherein: The voltage control device includes a comparator and a level processor; The comparator is connected to the battery and a pin of the processing device, and is used to compare the level value of the pin of the processing device with the reference voltage; The level processor is used to compare the level values between different pins of the processing device and send the comparison result to the level analysis device.

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