Parallel battery equalization discharge circuit and control method

Abstract

The invention provides a parallel battery equalization discharge circuit and a control method, the parallel battery equalization discharge circuit comprises a plurality of batteries arranged in parallel, and the positive electrode of each battery is connected with a battery management module; the battery management module comprises a voltage comparison circuit, a current acquisition circuit, a voltage reference circuit, an overcurrent detection circuit, an overcurrent protection circuit, an AND gate circuit and a battery output control circuit; one input end of the voltage comparison circuit is connected with the battery, and the other input end is connected with the voltage reference circuit; the input end of the current acquisition circuit is connected with the battery; one input end of the overcurrent detection circuit is connected with the voltage reference circuit, and the other input end of the overcurrent detection circuit is connected with the current acquisition circuit; the over-current detection circuit is connected with the over-current protection circuit; and one input end of the AND gate circuit is connected with the voltage comparison circuit, the other input end is connected with the overcurrent protection circuit, and the output end is connected with the battery output control circuit. The method has the advantages that the voltage of each battery can be well balanced, and the abnormal condition caused by sudden increase of the current can be prevented.

Description

[Technical field]

[0001] The present invention relates to the technical field of battery charging and discharging, and in particular to a parallel battery equalization discharge circuit and a control method. [Background technology]

[0002] At present, many high-power electronic devices rely on multi-battery parallel technology to enhance their endurance. However, there is a key problem in the actual use of multi-battery parallel technology, that is, the inconsistency of battery voltage. This inconsistency will cause the higher voltage battery to charge the lower voltage battery, which in turn causes the low-voltage battery to bear a larger current during both charging and discharging, which not only increases the load on the battery connection line, but also may cause abnormal conditions in the equipment and have a negative impact on the battery's service life. In view of the above-mentioned problems, the inventor of this case conducted an in-depth study on the problem, which led to the creation of this case. [Summary of the invention]

[0003] The technical problem to be solved by the present invention is to provide a parallel battery balanced discharge circuit and control method, so as to solve the problem that when the voltages of the batteries are inconsistent, the battery with higher voltage will charge the battery with lower voltage, thereby causing the low-voltage battery to bear a larger current during charging and discharging, which not only increases the load on the battery connection line, but also may cause abnormal conditions in the equipment and have a negative impact on the service life of the battery.

[0004] The present invention is achieved in that:

[0005] In a first aspect, a parallel battery balanced discharge circuit includes a plurality of batteries arranged in parallel; a positive electrode of each of the batteries is connected to a battery management module;

[0006] The battery management module includes a voltage comparison circuit, a current acquisition circuit, a voltage reference circuit, an overcurrent detection circuit, an overcurrent protection circuit, an AND gate circuit and a battery output control circuit; one input end of the voltage comparison circuit is connected to the positive electrode of the battery, and the other input end of the voltage comparison circuit is connected to the voltage reference circuit; the input end of the current acquisition circuit is connected to the positive electrode of the battery, one input end of the overcurrent detection circuit is connected to the voltage reference circuit, and the other input end of the overcurrent detection circuit is connected to the output end of the current acquisition circuit; the output end of the overcurrent detection circuit is connected to the input end of the overcurrent protection circuit; one input end of the AND gate circuit is connected to the output end of the voltage comparison circuit, the other input end of the AND gate circuit is connected to the output end of the overcurrent protection circuit, and the output end of the AND gate circuit is connected to the input end of the battery output control circuit.

[0007] Further, the voltage comparison circuit includes a first voltage comparator constructed using a first operational amplifier and an inverter;

[0008] The inverting input terminal of the first voltage comparator is connected to the positive pole of the battery, and the non-inverting input terminal of the first voltage comparator is connected to the voltage reference circuit; the output terminal of the first voltage comparator is connected to the input terminal of the inverter, and the output terminal of the inverter is connected to an input terminal of the AND gate circuit.

[0009] Furthermore, the current acquisition circuit includes a sampling resistor, an isolation amplifier and a second operational amplifier;

[0010] The sampling resistor is connected to the positive electrode of the battery; one end of the sampling resistor is connected to an input end of the isolation amplifier, and the other end of the sampling resistor is connected to another input end of the isolation amplifier; an output end of the isolation amplifier is connected to the positive input end of the second operational amplifier, and the other output end of the isolation amplifier is connected to the negative input end of the second operational amplifier; the output end of the second operational amplifier is connected to the overcurrent detection circuit.

[0011] Furthermore, the voltage reference circuit includes a plurality of voltage followers constructed using a third operational amplifier and a plurality of equal-resistance resistors; the positive electrode of each of the batteries is connected to the same-direction input terminal of a voltage follower, the reverse input terminal of each of the voltage followers is connected to the output terminal of the voltage follower, and the output terminal of each of the voltage followers is connected to one of the equal-resistance resistors; the voltage output by each of the equal-resistance resistors in parallel serves as the reference base voltage of each battery.

[0012] Further, the overcurrent detection circuit includes a second voltage comparator constructed using a fourth operational amplifier;

[0013] The output end of the voltage reference circuit is connected to the non-inverting input end of the second voltage comparator, the output end of the current acquisition circuit is connected to the reverse input end of the second voltage comparator, and the output end of the second voltage comparator is connected to the overcurrent protection circuit.

[0014] Furthermore, the overcurrent protection circuit includes a latch circuit formed by a first transistor and a second transistor and a protection circuit formed by a first MOS transistor and an optical coupler;

[0015] The output end of the overcurrent detection circuit and the latch circuit are connected to the G pole of the first MOS tube, the S pole of the first MOS tube is grounded, the latch circuit and the D pole of the first MOS tube are connected to the input end of the optocoupler, and the output end of the optocoupler is connected to the AND gate circuit; when the overcurrent detection circuit detects an overcurrent condition, the first MOS tube is kept in a closed state through the latch circuit.

[0016] Furthermore, it also includes an MCU control circuit; the latch circuit is connected to the MCU control circuit, and the MCU control circuit sends an overcurrent protection release signal to the latch circuit, so that the latch circuit clears the latch state to realize the current output of the battery.

[0017] Furthermore, the battery output control circuit includes a second MOS tube and a third MOS tube and a fourth MOS tube which are arranged in series back to back; the output end of the AND gate circuit is connected to the G pole of the second MOS tube, the S pole of the second MOS tube is grounded, and the D pole of the second MOS tube is connected to the G poles of the third MOS tube and the fourth MOS tube; the S pole of the third MOS tube is connected to the S pole of the fourth MOS tube, the D pole of the third MOS tube is connected to the positive pole of the battery, and the D pole of the fourth MOS tube is connected to the load device.

[0018] In a second aspect, a control method based on the parallel battery balanced discharge circuit is provided, the control method comprising the following steps:

[0019] Control the overcurrent detection circuit to detect the current of the battery, and trigger the output current abnormality signal when an abnormal situation is detected; at the same time, control the voltage comparison circuit to compare the voltage of the battery;

[0020] When an overcurrent condition is detected in a certain battery, the overcurrent protection circuit outputs a low-level signal to the AND gate circuit. The battery enable signal output by the AND gate circuit after processing is a low-level signal. The battery output control circuit controls the corresponding battery to stop output according to the low-level signal.

[0021] When it is detected that the current is normal but there is a voltage difference between the batteries connected in parallel, the overcurrent protection circuit outputs a high-level signal to the AND gate circuit; after the voltage comparison circuit compares the voltage, if the voltage comparison circuit finally outputs a low-level signal to the AND gate circuit, the battery enable signal output after the AND gate circuit is processed is a low-level signal, and the battery output control circuit controls the corresponding battery to suspend output according to the low-level signal; if the voltage comparison circuit finally outputs a high-level signal to the AND gate circuit, the battery enable signal output after the AND gate circuit is processed is a high-level signal, and the battery output control circuit controls the corresponding battery to power the load device according to the high-level signal;

[0022] When it is detected that the current is normal and the voltages of the batteries in parallel have reached a balanced state, the overcurrent protection circuit and the voltage comparison circuit both output high-level signals to the AND gate circuit. The battery enable signal output by the AND gate circuit after processing is a high-level signal. The battery output control circuit controls the batteries in parallel to power the load equipment at the same time according to the high-level signal.

[0023] Furthermore, the control method further comprises the following steps:

[0024] The current situation detected by the overcurrent detection circuit is fed back to the MCU control circuit in real time; when the overcurrent detection circuit detects that the battery has an overcurrent situation, the latch circuit in the overcurrent protection circuit is used to keep the first MOS tube in a closed state, so that the overcurrent protection circuit keeps outputting a low-level signal; when the battery current returns to normal, the MCU control circuit sends an overcurrent protection release signal to the latch circuit in the overcurrent protection circuit, so that the latch circuit clears the latch state to realize the battery current output.

[0025] By adopting the technical solution of the present invention, at least the following beneficial effects are achieved:

[0026] 1. Each battery is equipped with a battery management module, and the battery management module uses an AND gate circuit to perform a logical "AND" operation on the output results of the voltage comparison circuit and the overcurrent detection circuit, that is, the voltage comparison circuit and the overcurrent detection circuit work together to determine whether to control the battery to power the load device; so that in the specific use process, not only can the voltages of each battery be well balanced, that is, when the battery voltages are inconsistent, the battery with a higher voltage is preferentially controlled to power the load device, and when all the battery voltages are basically consistent, all the batteries in parallel are controlled to power the load device at the same time, thereby effectively preventing the battery with a higher voltage from charging the battery with a lower voltage, and reducing the load of the battery connection line; and the dual protection mechanism of the voltage comparison circuit and the overcurrent detection circuit working together can not only realize the balanced discharge function, but also effectively prevent abnormal conditions caused by a sudden increase in current, which can effectively improve the reliability of use, reduce damage to the load device caused by battery abnormalities, and at the same time increase the service life of the battery.

[0027] 2. The entire battery management module adopts a hardware structure design, and the hardware structure has the ability to respond quickly. It can quickly respond and cut off through hardware logic circuits under abnormal circumstances; therefore, compared with software implementation methods, it can not only effectively improve the response speed, but also prevent the occurrence of software false alarms and wrong alarms, and can improve the reliability of use.

Brief Description of the Drawings

[0028] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0029] Figure 1 It is a principle block diagram of a parallel battery equalization discharge circuit of the present invention;

[0030] Figure 2 It is a specific circuit structure diagram of the MCU control circuit in the present invention;

[0031] Figure 3 The present invention is a specific circuit structure diagram of a parallel battery equalization discharge circuit after removing the MCU control circuit.

[0032] Description of reference numerals:

[0033] Battery 100;

[0034] Voltage comparison circuit 200;

[0035] Current collection circuit 300;

[0036] Voltage reference circuit 400;

[0037] Overcurrent detection circuit 500;

[0038] Overcurrent protection circuit 600;

[0039] AND gate circuit 700;

[0040] Battery output control circuit 800;

[0041] MCU controls the circuit 900. [Specific implementation method]

[0042] In order to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0043] It should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing these embodiments and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. In addition, the terms "first", "second", etc., etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0044] Example 1

[0045] See also Figures 1 to 3As shown, a parallel battery equalization discharge circuit of the present invention includes a plurality of batteries 100 arranged in parallel; the positive electrode of each battery 100 is connected to a battery management module, so that each battery management module can manage a battery 100 separately. In the specific implementation, the number of batteries 100 connected in parallel in different application scenarios is different, and the specific number can be set according to actual needs; in order to better understand the technical solution of the present invention, the present invention is described in detail below by taking two batteries 100 (i.e., including two batteries BAT1 and BAT2) arranged in parallel as an example:

[0046] The battery management module includes a voltage comparison circuit 200, a current acquisition circuit 300, a voltage reference circuit 400, an overcurrent detection circuit 500, an overcurrent protection circuit 600, an AND gate circuit 700 and a battery output control circuit 800; wherein the battery 100 is used to power a load device, the voltage comparison circuit 200 is used to compare the voltage of the battery 100, the current acquisition circuit 300 is used to collect the current of the battery 100, the voltage reference circuit 400 is used to provide a reference voltage as a reference, the overcurrent detection circuit 500 is used to perform overcurrent detection on the battery 100, the overcurrent protection circuit 600 is used to implement an overcurrent protection function, the AND gate circuit 700 is used to perform a logical "AND" operation on the voltage comparison circuit 200 and the overcurrent protection circuit 600, and the battery output control circuit 800 is used as a switch to control the battery 100 to power on or off.

[0047] One input end of the voltage comparison circuit 200 is connected to the positive electrode of the battery 100, and the other input end of the voltage comparison circuit 200 is connected to the voltage reference circuit 400, so that the voltage comparison circuit 200 can compare the voltage of the battery 100 with the reference voltage provided by the voltage reference circuit 400; the input end of the current acquisition circuit 300 is connected to the positive electrode of the battery 100, one input end of the overcurrent detection circuit 500 is connected to the voltage reference circuit 400, and the other input end of the overcurrent detection circuit 500 is connected to the output end of the current acquisition circuit 300, so that the overcurrent detection circuit 500 can compare the current signal of the battery 100 with the voltage reference circuit 400 is used for comparison; the output end of the overcurrent detection circuit 500 is connected to the input end of the overcurrent protection circuit 600; one input end of the AND gate circuit 700 is connected to the output end of the voltage comparison circuit 200, the other input end of the AND gate circuit 700 is connected to the output end of the overcurrent protection circuit 600, and the output end of the AND gate circuit 700 is connected to the input end of the battery output control circuit 800, so that the AND gate circuit 700 can output the battery enable signal of the battery 100 to the battery output control circuit 800, so as to facilitate the battery output control circuit 800 to control the corresponding battery 100 to supply power or cut off power according to the battery enable signal.

[0048] By adopting the above technical solution of the present invention, at least the following beneficial effects are achieved:

[0049] 1. Each battery 100 is equipped with a battery management module, and the battery management module uses an AND gate circuit 700 to perform a logic "AND" operation on the output results of the voltage comparison circuit 200 and the overcurrent detection circuit 500, that is, the voltage comparison circuit 200 and the overcurrent detection circuit 500 work together to determine whether to control the battery 100 to power the load device; so that in the specific use process, not only can the voltage of each battery 100 be well balanced, that is, when the voltage of the battery 100 is inconsistent, the battery 100 with a higher voltage is preferentially controlled to power the load device, and when all batteries 100 are in a state of being ... 00 voltages are basically the same, then all the batteries 100 in parallel are controlled to power the load equipment at the same time, thereby effectively preventing the battery 100 with a higher voltage from charging the battery 100 with a lower voltage, and reducing the load on the battery 100 connection line; and the dual protection mechanism of the voltage comparison circuit 200 and the overcurrent detection circuit 500 can not only realize the balanced discharge function, but also effectively prevent abnormal situations caused by sudden increase in current, which can effectively improve the reliability of use, reduce damage to the load equipment due to abnormal battery 100, and at the same time increase the service life of the battery 100.

[0050] 2. The entire battery management module adopts a hardware structure design, and the hardware structure has the ability to respond quickly. It can quickly respond and cut off through hardware logic circuits under abnormal circumstances; therefore, compared with software implementation methods, it can not only effectively improve the response speed, but also prevent the occurrence of software false alarms and wrong alarms, and can improve the reliability of use.

[0051] In an embodiment of the present invention, the voltage comparison circuit 200 includes a first voltage comparator constructed using a first operational amplifier U1A (U7A) and an inverter U11 (U6), wherein the first voltage comparator can generate one of the enable signals of the battery after comparison, and the inverter is used to invert the enable signal output by the first voltage comparator;

[0052] The inverting input terminal of the first voltage comparator is connected to the positive pole of the battery 100, and the non-inverting input terminal of the first voltage comparator is connected to the voltage reference circuit 400; the output terminal of the first voltage comparator is connected to the input terminal of the inverter U11 (U6), and the output terminal of the inverter U11 (U6) is connected to an input terminal of the AND gate circuit 700.

[0053] When the voltage comparison circuit 200 is in operation, when the voltage of the battery 100 exceeds the reference voltage VREF provided by the voltage reference circuit 400, the output of the first voltage comparator is a low-level signal, which is inverted by the inverter U11 (U6) and outputs a high-level signal to the gate circuit 700; and when the voltage of the battery 100 is lower than the reference voltage VREF provided by the voltage reference circuit 400, the output of the first voltage comparator is a high-level signal, which is inverted by the inverter U11 (U6) and outputs a low-level signal to the gate circuit 700.

[0054] In an embodiment of the present invention, the current acquisition circuit 300 includes a sampling resistor R10 (R37), an isolation amplifier U19 (U9) and a second operational amplifier U1B (U7B), wherein the sampling resistor R10 (R37) is used to collect the current of the battery 100; the isolation amplifier U19 (U9) is used to provide electrical isolation between the input, output and power supply during signal transmission, thereby preventing the propagation of interference signals, protecting the device, and ensuring the quality and accuracy of the signal; the second operational amplifier U1B (U7B) is used to amplify the signal;

[0055] The sampling resistor R10 (R37) is connected to the positive electrode of the battery 100, so that the sampling resistor R10 (R37) can collect current from the battery 100; one end of the sampling resistor R10 (R37) is connected to an input end of the isolation amplifier U19 (U9), and the other end of the sampling resistor R10 (R37) is connected to another input end of the isolation amplifier U19 (U9), so that the voltage across the sampling resistor R10 (R37) is first isolated and amplified by the isolation amplifier U19 (U9); an output end of the isolation amplifier U19 (U9) is connected to the positive input end of the second operational amplifier U1B (U7B), and the other output end of the isolation amplifier U19 (U9) is connected to the negative input end of the second operational amplifier U1B (U7B); the output end of the second operational amplifier U1B (U7B) is connected to the overcurrent detection circuit 500.

[0056] When the current acquisition circuit 300 is working, the current value of the battery 100 can be calculated according to Ohm's law (i.e., i=U / R). The voltage across the sampling resistor R10 (R37) is first isolated and amplified by the isolation amplifier U19 (U9), and then output to the second operational amplifier U1B (U7B) for further amplification, thereby obtaining the final current acquisition results VCC1 and VCC2, which are used as sampling voltages for overcurrent protection; wherein, the calculation formula of the sampling voltage is U=I (current flowing through the sampling resistor)*R (resistance of the sampling resistor)*amplification factor (fixed gain of the isolation amplifier)*amplification factor (adjustable gain of the second operational amplifier).

[0057] In an embodiment of the present invention, the voltage reference circuit 400 includes a plurality of voltage followers constructed using a third operational amplifier and a plurality of equal-resistance resistors. Since the present invention takes two batteries 100 as an example, the voltage reference circuit 400 includes two voltage followers constructed using a third operational amplifier U4A (U4B) and two equal-resistance resistors R20 (R25); the positive electrode of each of the batteries 100 is connected to the same-direction input terminal of the voltage follower, the reverse input terminal of each of the voltage followers is connected to the output terminal of the voltage follower, and the output terminal of each of the voltage followers is connected to one of the equal-resistance resistors; the voltage output by each of the equal-resistance resistors in parallel serves as the reference base voltage of each battery 100.

[0058] The present invention outputs the voltage of each battery 100 by using a voltage follower designed with an operational amplifier, and the voltages output by all the batteries 100 are connected in parallel through resistors of equal resistance, and the voltage output in parallel is used as a reference voltage for each battery 100, so that when the voltages of the parallel batteries 100 are inconsistent, the battery 100 with a higher voltage can be preferentially controlled to power the load device, while the battery 100 with a lower voltage stops powering the load device, so that the voltages of each battery 100 can be restored to be consistent.

[0059] In an embodiment of the present invention, the overcurrent detection circuit 500 includes a second voltage comparator constructed by using a fourth operational amplifier U5A (U14A), that is, the present invention uses an operational amplifier to construct a voltage comparator to achieve the issuance of an overcurrent protection signal;

[0060] The output end of the voltage reference circuit 400 is connected to the non-inverting input end of the second voltage comparator, the output end of the current acquisition circuit 300 is connected to the inverting input end of the second voltage comparator, and the output end of the second voltage comparator is connected to the overcurrent protection circuit 600.

[0061] Taking BAT1 battery as an example, the current signal output by the current acquisition circuit 300 is compared with the reference voltage VREF1 provided by the voltage reference circuit 400 through the fourth operational amplifier U5A, thereby outputting the comparison result; wherein, the reference voltage VREF1 is connected to the non-inverting input terminal of the fourth operational amplifier U5A, and the current signal to be compared is connected to the inverting input terminal of the fourth operational amplifier U5A, thereby forming a comparison circuit. Taking the current of 10.2A, the sampling resistor of 10mΩ, and the reference voltage of 2.5V as an example, the sampling voltage U=10.2A (current flowing through the sampling resistor R10)*0.01Ω (resistance of the sampling resistor R10)*8.2 (fixed gain of the isolation amplifier U9)*3 (the second operational amplifier U1B amplifies 3 times)=2.51V; when the sampling voltage U of the overcurrent protection exceeds the reference voltage 2.5V, the first pin of the fourth operational amplifier U5A will output a low-level signal to trigger the overcurrent protection function.

[0062] In an embodiment of the present invention, the overcurrent protection circuit 600 includes a latch circuit formed by a first transistor Q11A (Q10A) and a second transistor Q11B (Q10B) and a protection circuit formed by a first MOS transistor Q6 (Q12) and an optocoupler U3 (U12); wherein the latch circuit is used to ensure that the first MOS transistor Q6 (Q12) can continue to remain in a closed state when an overcurrent occurs; and the protection circuit is used to shut down the output of the battery 100 when an overcurrent occurs.

[0063] The output end of the overcurrent detection circuit 500 and the latch circuit are connected to the G pole of the first MOS tube Q6 (Q12), the S pole of the first MOS tube Q6 (Q12) is grounded, the latch circuit and the D pole of the first MOS tube Q6 (Q12) are connected to the input end of the optocoupler U3 (U12), and the output end of the optocoupler U3 (U12) is connected to the AND gate circuit 700; when the overcurrent detection circuit 500 detects an overcurrent condition, the first MOS tube Q6 (Q12) is kept in a closed state through the latch circuit.

[0064] When the overcurrent protection circuit 600 of the present invention is working, taking the BAT1 battery as an example, when an overcurrent occurs in BAT1, the G pole voltage of the first MOS tube Q6 will decrease, causing the first MOS tube Q6 to be continuously turned off and the optocoupler U3 to be non-conductive; at the same time, the latch circuit is maintained by the inter-stage conduction voltage of the first transistor Q11A and the second transistor Q11B, thereby ensuring that the first MOS tube Q6 is continuously kept in a closed state, so that the battery 100 cannot output.

[0065] In an embodiment of the present invention, the battery management module also includes an MCU control circuit 900; the latch circuit is connected to the MCU control circuit 900, and the MCU control circuit 900 sends an overcurrent protection release signal to the latch circuit, so that the latch circuit clears the latch state to realize the current output of the battery 100.

[0066] The present invention designs the battery management module to also include an MCU control circuit 900, and connects the latch circuit to the MCU control circuit 900, so that during specific operation, the current condition detected by the overcurrent detection circuit 500 can be fed back to the MCU control circuit 900; and when an overcurrent condition occurs in the battery 100, only when the MCU control circuit 900 sends an overcurrent protection release signal to the latch circuit, can the latch circuit clear the latch state, thereby allowing the battery 100 to output current.

[0067] In an embodiment of the present invention, the battery output control circuit 800 includes a second MOS transistor Q3 (Q8) and a third MOS transistor Q1 (Q5) and a fourth MOS transistor Q2 (Q7) which are arranged in series back to back; the output end of the AND gate circuit 700 is connected to the G pole of the second MOS transistor Q3 (Q8), the S pole of the second MOS transistor Q3 (Q8) is grounded, and the D pole of the second MOS transistor Q3 (Q8) is connected to the G poles of the third MOS transistor Q1 (Q5) and the fourth MOS transistor Q2 (Q7); the S pole of the third MOS transistor Q1 (Q5) is connected to the S pole of the fourth MOS transistor Q2 (Q7), the D pole of the third MOS transistor Q1 (Q5) is connected to the positive pole of the battery 100, and the D pole of the fourth MOS transistor Q2 (Q7) is connected to the load device. When the battery output control circuit 800 of the present invention is working, taking the BAT1 battery as an example, when the output of the AND gate circuit 700 is a high-level signal, the second MOS transistor Q3 will be turned on, and then the third MOS transistor Q1 and the fourth MOS transistor Q2 connected back to back will also be turned on, so that BAT1 can supply power to the back-end load device; and when the output of the AND gate circuit 700 is a low-level signal, the second MOS transistor Q3 will not be turned on, and then the third MOS transistor Q1 and the fourth MOS transistor Q2 connected back to back will also be turned on, and at this time, BAT1 cannot supply power to the back-end load device.

[0068] The present invention forms a bidirectional electronic switch by utilizing a third MOS tube Q1 (Q5) and a fourth MOS tube Q2 (Q7) which are arranged in series back to back and a second MOS tube Q3 (Q8), which can reliably prevent the batteries 100 from charging each other due to a voltage difference, thereby better protecting the batteries 100 and improving the service life of the batteries 100.

[0069] In the present invention, the AND gate circuit 700 is implemented by the AND gate chip U2 (U8). When the AND gate circuit 700 is working, only when the outputs of the voltage comparison circuit 200 and the overcurrent detection circuit 500 are both high-level signals, the AND gate circuit 700 will generate a high-level signal output, so that the battery output control circuit 800 can control the battery 100 to supply power to the load device. By adopting the design of the AND gate circuit 700, the possible misjudgment of a single hardware circuit can be effectively avoided, thereby improving the reliability of hardware protection.

[0070] Example 2

[0071] See also Figures 1 to 3 As shown, the present invention provides a control method for a parallel battery equalization discharge circuit, wherein the specific circuit structure of the parallel battery equalization discharge circuit is described in detail in Embodiment 1, so it will not be described in detail here; the control method comprises the following steps:

[0072] The overcurrent detection circuit 500 is controlled to detect the current of the battery 100, and triggers the output current abnormality signal when an abnormal situation (i.e., an overcurrent situation) is detected; at the same time, the voltage comparison circuit 200 is controlled to compare the voltage of the battery 100 to determine whether the voltages of the batteries 100 connected in parallel are consistent;

[0073] When an overcurrent condition is detected in a certain battery 100, the overcurrent protection circuit 600 outputs a low-level signal to the AND gate circuit 700. The battery enable signal output by the AND gate circuit 700 after processing is a low-level signal. The battery output control circuit 800 controls the corresponding battery 100 to stop output according to the low-level signal. Since the present invention adopts a battery management module independently set for each battery 100, when an overcurrent condition occurs in a certain battery 100, the battery management module controller corresponding to the battery 100 can be used to stop output, while other normal batteries 100 can continue to output normally;

[0074] When it is detected that the current is normal but there is a voltage difference between the batteries 100 connected in parallel, the overcurrent protection circuit 600 outputs a high-level signal to the AND gate circuit 700; after the voltage comparison circuit 200 compares the voltage, if the voltage comparison circuit 200 finally outputs a low-level signal to the AND gate circuit 700, the battery enable signal output after processing by the AND gate circuit 700 is a low-level signal, and the battery output control circuit 800 controls the corresponding battery 100 to suspend output according to the low-level signal; if the voltage comparison circuit 200 finally outputs a high-level signal to the AND gate circuit 700, the battery enable signal output after processing by the AND gate circuit 700 is a high-level signal, and the battery output control circuit 800 controls the corresponding battery 100 to power the load device according to the high-level signal; that is, when the present invention is working, when the voltage comparison circuit 200 outputs a low-level signal, it means that the voltage of the battery 100 is low, and at this time, the battery 100 will be controlled to suspend output first, so as to give priority to using the battery 100 with a higher voltage to power the load device, so as to achieve the purpose of balancing the voltages of the batteries 100;

[0075] When it is detected that the current is normal and the voltages of the batteries 100 connected in parallel have reached a balanced state, the overcurrent protection circuit 600 and the voltage comparison circuit 200 both output high-level signals to the AND gate circuit 700, that is, when the current is normal and the voltages of the batteries 100 are consistent, the overcurrent protection circuit 600 and the voltage comparison circuit 200 both output high-level signals; the battery enable signal output by the AND gate circuit 700 after processing is a high-level signal, and the battery output control circuit 800 controls the batteries 100 connected in parallel according to the high-level signal to simultaneously power the load device.

[0076] In an embodiment of the present invention, the control method further comprises the following steps:

[0077] The current condition detected by the overcurrent detection circuit 500 is fed back to the MCU control circuit 900 in real time; when the overcurrent detection circuit 500 detects that the battery 100 has an overcurrent condition, the latch circuit in the overcurrent protection circuit 600 is used to keep the first MOS tube in a closed state, so that the overcurrent protection circuit 600 keeps outputting a low-level signal to ensure that the battery 100 cannot output current; when the current of the battery 100 returns to normal, the MCU control circuit 900 sends an overcurrent protection release signal to the latch circuit in the overcurrent protection circuit 600, so that the latch circuit clears the latch state to achieve current output of the battery 100.

[0078] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A parallel battery balanced discharge circuit, comprising a plurality of batteries arranged in parallel; characterized in that: The positive electrode of each battery is connected to a battery management module; The battery management module includes a voltage comparison circuit, a current acquisition circuit, a voltage reference circuit, an overcurrent detection circuit, an overcurrent protection circuit, an AND gate circuit and a battery output control circuit; one input end of the voltage comparison circuit is connected to the positive electrode of the battery, and the other input end of the voltage comparison circuit is connected to the voltage reference circuit; the input end of the current acquisition circuit is connected to the positive electrode of the battery, one input end of the overcurrent detection circuit is connected to the voltage reference circuit, and the other input end of the overcurrent detection circuit is connected to the output end of the current acquisition circuit; the output end of the overcurrent detection circuit is connected to the input end of the overcurrent protection circuit; one input end of the AND gate circuit is connected to the output end of the voltage comparison circuit, the other input end of the AND gate circuit is connected to the output end of the overcurrent protection circuit, and the output end of the AND gate circuit is connected to the input end of the battery output control circuit.

2. The parallel battery equalization discharge circuit according to claim 1, characterized in that: The voltage comparison circuit includes a first voltage comparator constructed by a first operational amplifier and an inverter; The inverting input terminal of the first voltage comparator is connected to the positive pole of the battery, and the non-inverting input terminal of the first voltage comparator is connected to the voltage reference circuit; the output terminal of the first voltage comparator is connected to the input terminal of the inverter, and the output terminal of the inverter is connected to an input terminal of the AND gate circuit.

3. The parallel battery equalization discharge circuit according to claim 1, characterized in that: The current acquisition circuit includes a sampling resistor, an isolation amplifier and a second operational amplifier; The sampling resistor is connected to the positive electrode of the battery; one end of the sampling resistor is connected to an input end of the isolation amplifier, and the other end of the sampling resistor is connected to another input end of the isolation amplifier; an output end of the isolation amplifier is connected to the positive input end of the second operational amplifier, and the other output end of the isolation amplifier is connected to the negative input end of the second operational amplifier; the output end of the second operational amplifier is connected to the overcurrent detection circuit.

4. The parallel battery equalization discharge circuit according to claim 1, characterized in that: The voltage reference circuit includes a plurality of voltage followers constructed using a third operational amplifier and a plurality of equal-resistance resistors; the positive electrode of each battery is connected to the same-direction input terminal of a voltage follower, the reverse input terminal of each voltage follower is connected to the output terminal of the voltage follower, and the output terminal of each voltage follower is connected to one of the equal-resistance resistors; the voltage output by each of the equal-resistance resistors in parallel serves as the reference base voltage of each battery.

5. The parallel battery equalization discharge circuit according to claim 1, characterized in that: The overcurrent detection circuit includes a second voltage comparator constructed using a fourth operational amplifier; The output end of the voltage reference circuit is connected to the non-inverting input end of the second voltage comparator, the output end of the current acquisition circuit is connected to the reverse input end of the second voltage comparator, and the output end of the second voltage comparator is connected to the overcurrent protection circuit.

6. The parallel battery equalization discharge circuit according to claim 1, characterized in that: The overcurrent protection circuit includes a latch circuit formed by a first transistor and a second transistor and a protection circuit formed by a first MOS tube and an optical coupler; The output end of the overcurrent detection circuit and the latch circuit are connected to the G pole of the first MOS tube, the S pole of the first MOS tube is grounded, the latch circuit and the D pole of the first MOS tube are connected to the input end of the optocoupler, and the output end of the optocoupler is connected to the AND gate circuit; when the overcurrent detection circuit detects an overcurrent condition, the first MOS tube is kept in a closed state through the latch circuit.

7. The parallel battery equalization discharge circuit according to claim 6, characterized in that: It also includes an MCU control circuit; the latch circuit is connected to the MCU control circuit, and the MCU control circuit sends an overcurrent protection release signal to the latch circuit, so that the latch circuit clears the latch state to realize the current output of the battery.

8. The parallel battery equalization discharge circuit according to claim 1, characterized in that: The battery output control circuit includes a second MOS tube and a third MOS tube and a fourth MOS tube which are arranged in series back to back; the output end of the AND gate circuit is connected to the G pole of the second MOS tube, the S pole of the second MOS tube is grounded, and the D pole of the second MOS tube is connected to the G poles of the third MOS tube and the fourth MOS tube; the S pole of the third MOS tube is connected to the S pole of the fourth MOS tube, the D pole of the third MOS tube is connected to the positive pole of the battery, and the D pole of the fourth MOS tube is connected to the load device.

9. A control method for a parallel battery equalization discharge circuit according to any one of claims 1 to 8, characterized in that: The control method comprises the following steps: Control the overcurrent detection circuit to detect the current of the battery, and trigger the output current abnormality signal when an abnormal situation is detected; at the same time, control the voltage comparison circuit to compare the voltage of the battery; When an overcurrent condition is detected in a certain battery, the overcurrent protection circuit outputs a low-level signal to the AND gate circuit. The battery enable signal output by the AND gate circuit after processing is a low-level signal. The battery output control circuit controls the corresponding battery to stop output according to the low-level signal. When it is detected that the current is normal but there is a voltage difference between the batteries connected in parallel, the overcurrent protection circuit outputs a high-level signal to the AND gate circuit; after the voltage comparison circuit compares the voltage, if the voltage comparison circuit finally outputs a low-level signal to the AND gate circuit, the battery enable signal output after the AND gate circuit is processed is a low-level signal, and the battery output control circuit controls the corresponding battery to suspend output according to the low-level signal; if the voltage comparison circuit finally outputs a high-level signal to the AND gate circuit, the battery enable signal output after the AND gate circuit is processed is a high-level signal, and the battery output control circuit controls the corresponding battery to power the load device according to the high-level signal; When it is detected that the current is normal and the voltages of the batteries in parallel have reached a balanced state, the overcurrent protection circuit and the voltage comparison circuit both output high-level signals to the AND gate circuit. The battery enable signal output by the AND gate circuit after processing is a high-level signal. The battery output control circuit controls the batteries in parallel to power the load equipment at the same time according to the high-level signal.

10. The control method of a parallel battery equalization discharge circuit as claimed in claim 9, characterized in that: The control method further comprises the following steps: The current situation detected by the overcurrent detection circuit is fed back to the MCU control circuit in real time; when the overcurrent detection circuit detects that the battery has an overcurrent situation, the latch circuit in the overcurrent protection circuit is used to keep the first MOS tube in a closed state, so that the overcurrent protection circuit keeps outputting a low-level signal; when the battery current returns to normal, the MCU control circuit sends an overcurrent protection release signal to the latch circuit in the overcurrent protection circuit, so that the latch circuit clears the latch state to realize the battery current output.

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