BMS of lithium battery and electrical equipment

Abstract

The invention discloses a BMS (Battery Management System) of a lithium battery and electrical equipment, which are applied to the field of lithium battery charging and comprise a power supply circuit, a voltage stabilizing circuit, a comparison circuit, an activation circuit and a single chip microcomputer. When a charging power supply is connected during shutdown, the power supply circuit carries out voltage reduction processing on charging voltage and then transmits the charging voltage to the voltage stabilizing circuit, then the voltage stabilizing circuit outputs reference voltage after voltage division, the comparison circuit outputs a result to the activation circuit based on comparison of external power supply voltage and the reference voltage, and the activation circuit outputs an activation signal to the single-chip microcomputer. The single-chip microcomputer activates the lithium battery to charge. The whole BMS is completed based on a hardware circuit, compared with the scheme that charging activation control is carried out on the BMS of the lithium battery through an MCU, the lithium battery activation and charging failure caused by unsuccessful power supply to the MCU is avoided, the application scene is wider, the charging activation reliability is higher, and the activation energy consumption and the preparation cost are reduced.

Description

Technical Field

[0001] The present invention relates to the field of lithium battery charging, and in particular to a BMS and electrical equipment of a lithium battery. Background Art

[0002] Driven by modern technology, lithium batteries have become the preferred energy medium for various electric devices and energy storage systems. However, lithium batteries have a series of potential safety hazards during charging and discharging. At the same time, their performance and life are also subject to some limitations. In order to solve these problems, the lithium battery management system (BMS) came into being. BMS is an intelligent battery management solution that uses various sensors, controllers and complex algorithms to achieve precise monitoring and intelligent control of batteries. It can detect external power input within the rechargeable voltage range without human intervention, and wake up the charging module of the lithium battery for charging.

[0003] Currently, most lithium battery BMS activation relies on a microcontroller unit (MCU). However, the MCU cannot work directly with the voltage and current provided by an external power supply, and requires additional configuration of the MCU power supply device. In actual operation, the MCU startup process requires a lot of energy consumption, which does not meet the energy consumption restrictions of some low-power products. Therefore, the MCU power supply device cannot wake up the MCU, which greatly reduces the probability of lithium battery charging activation. At the same time, the MCU solution is costly. Therefore, the current problems of low battery activation rate, high power consumption and high cost of charging activation control in lithium battery BMS need to be solved urgently. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a BMS and electrical equipment for lithium batteries, which effectively solves the current high power consumption and high cost BMS charging activation control problem of lithium batteries. The specific scheme is as follows:

[0005] In a first aspect, the present application provides a BMS for a lithium battery, comprising: a power supply circuit, a voltage stabilizing circuit, a comparison circuit, an activation circuit and a single-chip microcomputer;

[0006] The input end of the power supply circuit is connected to the positive electrode of the external power supply, and the output end of the power supply circuit is connected to the voltage stabilizing circuit and the comparison circuit, so as to provide an input electrical signal to the voltage stabilizing circuit and power the comparison circuit;

[0007] The output terminal of the voltage stabilizing circuit is connected to the first input terminal of the comparison circuit, and is used to provide a reference voltage to the comparison circuit;

[0008] The second input terminal of the comparison circuit is connected to the positive electrode of the external power supply;

[0009] The output end of the comparison circuit is connected to the activation circuit, and is used to provide the activation circuit with a comparison result of comparing the positive voltage of the external power supply and the reference voltage;

[0010] The output end of the activation circuit is connected to the single-chip microcomputer, and is used to provide an activation signal to the single-chip microcomputer when the comparison result of the comparison circuit is a high level;

[0011] The single chip microcomputer is used to activate the entire BMS after receiving the activation signal, so that the lithium battery can be charged.

[0012] Optionally, the voltage stabilization circuit includes: a voltage stabilizer, a first resistor, a second resistor, a third resistor and a first capacitor;

[0013] The cathode of the voltage stabilizer, the second end of the first resistor and the first end of the second resistor are connected, and the common end of the three is used as the output end of the voltage stabilization circuit to output the reference voltage;

[0014] The reference end of the voltage regulator, the second end of the second resistor and the first end of the third resistor are connected;

[0015] The second end of the third resistor and the first end of the first capacitor are connected to the negative electrode of the battery pack;

[0016] The second end of the first capacitor, the first end of the first resistor and the output end of the power supply circuit are connected.

[0017] Optionally, the comparison circuit includes: a fourth resistor, a fifth resistor, a sixth resistor, a comparator and a second capacitor;

[0018] The first end of the fourth resistor is connected to the positive electrode of the external power supply;

[0019] The second end of the fourth resistor and the first end of the fifth resistor are connected to the same-direction input end of the comparator;

[0020] The second end of the fifth resistor is connected to the negative electrode of the battery pack;

[0021] The first end of the sixth resistor, the positive power supply end of the comparator and the output end of the power supply circuit are connected;

[0022] The second end of the sixth resistor is connected to the output end of the comparator;

[0023] The first end of the second capacitor and the output end of the voltage stabilizing circuit are connected to the inverting input end of the comparator;

[0024] The second end of the second capacitor and the negative power supply end of the comparator are connected to the negative electrode of the battery pack.

[0025] Optionally, the activation circuit includes an isolation switch and a first diode;

[0026] The control end of the isolation switch is connected to the output end of the comparison circuit;

[0027] The first end of the isolation switch is connected to the anode of the first diode;

[0028] The second end of the isolation switch is connected to the output end of the battery management chip through a resistor;

[0029] The cathode of the diode is connected to the single chip microcomputer.

[0030] Optionally, the isolation switch is a phototransistor optical coupler, including an infrared emitting diode and a phototransistor detector;

[0031] The anode of the infrared emitting diode is connected to the output end of the comparison circuit;

[0032] The cathode of the infrared emitting diode is connected to the negative electrode of the battery pack;

[0033] The first end of the phototransistor detector is connected to the single chip microcomputer;

[0034] The second end of the phototransistor detector is connected to the output end of the battery management chip through a resistor.

[0035] Optionally, the power supply circuit includes: a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first inductor, a second inductor, a third capacitor, a fourth capacitor, a fifth capacitor, a second diode D2 and a DC-DC chip;

[0036] A first end of the seventh resistor is connected to the positive electrode of the external power supply, and a second end of the seventh resistor is connected to the first end of the first inductor;

[0037] The second end of the first inductor, the input pin of the DC-DC chip, the first end of the eighth resistor and the first end of the third capacitor are connected;

[0038] The second end of the third capacitor is connected to the negative electrode of the battery pack;

[0039] The second end of the eighth resistor is connected to the enable control pin of the DC-DC chip;

[0040] The start pin of the DC-DC chip is connected to the first end of the fourth capacitor, and the ground pin of the DC-DC chip is connected to the negative electrode of the battery pack;

[0041] The second end of the fourth capacitor, the cathode of the second diode D2, and the first end of the second inductor are connected to the inductor pin of the DC-DC chip;

[0042] The anode of the second diode D2 is connected to the negative electrode of the battery pack;

[0043] The second end of the second inductor, the first end of the ninth resistor, and the first end of the fifth capacitor are connected to the output end of the power supply circuit;

[0044] The second end of the ninth resistor and the first end of the tenth resistor are connected to the output feedback pin of the DC-DC chip;

[0045] The second end of the tenth resistor is connected to the negative electrode of the battery pack.

[0046] Optionally, the power supply circuit further includes: a third diode and a fourth diode;

[0047] A common end of the cathodes of the third diode and the fourth diode is connected to the positive electrode of the external power supply;

[0048] A common terminal of anodes of the third diode and the fourth diode is connected to the first terminal of the first inductor.

[0049] Optionally, the power supply circuit further includes: a sixth capacitor and a seventh capacitor;

[0050] The first end of the sixth capacitor and the first end of the seventh capacitor are connected to the output end of the power supply circuit;

[0051] The second end of the sixth capacitor and the second end of the seventh capacitor are connected to the negative electrode of the battery pack.

[0052] Optionally, it also includes: a protection circuit;

[0053] The protection circuit includes a relay, a triode, an eleventh resistor, a twelfth resistor, a fifth diode and an eighth capacitor; the relay includes a coil and a single-pole double-gate switch;

[0054] The first end of the single-pole double-gate switch of the relay, the first end of the eighth capacitor, the third voltage-stabilizing source and the positive electrode of the external power supply are connected;

[0055] The second end of the single-pole double-gate switch of the relay and the second end of the eighth capacitor are connected to the input end of the comparison circuit;

[0056] The third end of the single-pole double-gate switch of the relay is suspended;

[0057] The first end of the coil of the relay, the second voltage stabilizing source and the cathode of the fifth diode are connected;

[0058] The second end of the coil of the relay, the anode of the fifth diode and the collector of the transistor are connected;

[0059] The base of the transistor, the first end of the twelfth resistor and the second end of the eleventh resistor are connected;

[0060] The first end of the eleventh resistor is connected to the load removal signal terminal of the single chip microcomputer;

[0061] The second end of the twelfth resistor and the emitter of the transistor are grounded.

[0062] In the second aspect, the present application provides an electrical device, including a BMS for lithium batteries. It can be seen that the present application discloses a BMS for lithium batteries, including a power supply circuit, a voltage stabilizing circuit, a comparison circuit activation circuit and a single-chip microcomputer. When the BMS is turned off and a charging power supply is connected to the outside, the power supply circuit processes the voltage and transmits it to the voltage stabilizing circuit, so that the voltage stabilizing circuit outputs a reference voltage after voltage division, and the comparison circuit outputs the result of the comparison between the external power supply voltage and the reference voltage to the activation circuit, and the activation circuit outputs an activation signal to the single-chip microcomputer, and the single-chip microcomputer activates the entire BMS, and the lithium battery is charged. The entire BMS is completed based on a hardware circuit, and the external power input voltage is processed by the BMS of the lithium battery, and the external power supply voltage is screened by comparing the external power supply voltage and the reference voltage. Compared with the solution of using MCU to realize the charging activation control of the BMS of the lithium battery, the present application avoids the failure of lithium battery charging activation caused by unsuccessful power supply to the MCU, has a wider range of application scenarios, and has higher charging activation reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0064] Figure 1 A system framework diagram of a BMS for a lithium battery provided in an embodiment of the present application;

[0065] Figure 2 A BMS voltage stabilizing circuit diagram of a lithium battery provided in an embodiment of the present application;

[0066] Figure 3 A BMS comparison circuit diagram of a lithium battery provided in an embodiment of the present application;

[0067] Figure 4A BMS activation circuit diagram of a lithium battery provided in an embodiment of the present application;

[0068] Figure 5 A BMS power supply circuit diagram of a lithium battery provided in an embodiment of the present application;

[0069] Figure 6 A BMS protection circuit diagram of a lithium battery provided in an embodiment of the present application;

[0070] The reference numerals are as follows: 10 is a power supply circuit, 11 is a voltage stabilizing circuit, 12 is a comparison circuit, 13 is an activation circuit, and 14 is a single chip microcomputer. DETAILED DESCRIPTION

[0071] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] The core of this application is to provide a BMS and electrical equipment for lithium batteries.

[0073] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0074] Driven by modern technology, lithium batteries have become the preferred energy medium for various electric devices and energy storage systems. However, lithium batteries have a series of potential safety hazards during charging and discharging. At the same time, their performance and life are also subject to some restrictions. In order to solve these problems, lithium battery BMS came into being. In traditional lithium battery BMS, most rely on MCU to complete. However, in BMS that uses MCU to realize lithium battery charging activation, MCU cannot work directly through the voltage and current provided by the external power supply, and it is necessary to configure the MCU power supply device additionally. In the actual operation process, the MCU startup process requires a lot of energy consumption, which is inconsistent with the energy consumption of some low-power products. Subject to certain restrictions, the MCU power supply device cannot wake up the MCU, which greatly reduces the probability of lithium battery charging activation. At the same time, the cost of using MCU is high. Therefore, it is urgent to solve the low battery activation rate, high power consumption and high cost of charging activation control of lithium battery BMS.

[0075] Figure 1A system framework diagram of a lithium battery BMS provided in an embodiment of the present application. As shown in the figure, in order to solve the above problems, the present embodiment provides a lithium battery BMS, including: a power supply circuit 10, a voltage stabilizing circuit 11, a comparison circuit 12, an activation circuit 13 and a single-chip microcomputer 14;

[0076] The input end of the power supply circuit 10 is connected to the positive electrode of the external power supply, and the output end of the power supply circuit 10 is connected to the voltage stabilizing circuit 11 and the comparison circuit 12, so as to provide an input electrical signal to the voltage stabilizing circuit 11 and power the comparison circuit 12;

[0077] The output terminal of the voltage stabilizing circuit 11 is connected to the first input terminal of the comparison circuit 12, and is used to provide a reference voltage to the comparison circuit 12;

[0078] The second input terminal of the comparison circuit 12 is connected to the positive electrode of the external power supply;

[0079] The output end of the comparison circuit 12 is connected to the activation circuit 13, and is used to provide the activation circuit 13 with a comparison result of the positive voltage of the external power supply and the reference voltage;

[0080] The output end of the activation circuit 13 is connected to the single-chip computer 14, and is used to provide an activation signal to the single-chip computer 14 when the comparison result of the comparison circuit 12 is a high level;

[0081] The single chip microcomputer 14 is used to activate the entire BMS after receiving the activation signal, so that the lithium battery can be charged.

[0082] like Figure 1 As shown, when the lithium battery device is in the shutdown state, the external power supply or load is connected to the lithium battery system through the screw column. When the external power supply is charging the lithium battery, the external power input is transmitted as a signal and power supply to the comparison circuit 12 and the power supply circuit 10 in the BMS of the lithium battery. The light-colored lines in the figure are signals, and the dark-colored lines are power supply. At this time, the power supply circuit 10 processes the external power supply voltage and outputs it to the voltage stabilizing circuit 11 and the comparison circuit 12 as a signal and power supply. After receiving the voltage signal of the power supply circuit 10, the voltage stabilizing circuit outputs a stable voltage to the comparison circuit 12 as a reference voltage. At this time, the comparison circuit 12 compares the received external power supply voltage with the reference voltage output by the voltage stabilizing circuit 11. When the external power supply voltage is higher than the reference voltage output by the voltage stabilizing circuit 11, the comparison circuit 12 transmits the comparison result to the activation circuit 13 in the form of an electrical signal. After receiving it, the activation circuit 13 transmits the signal for activating battery charging to the single-chip microcomputer 14. The single-chip microcomputer 14 turns on the entire system and charges the lithium battery. It can be understood that the activation circuit 13 here is equivalent to a controllable switch. When the signal transmitted to the activation circuit 13 by the comparison circuit 12 meets the preset condition, the activation circuit 13 is turned on.

[0083] In this embodiment, when the external power supply voltage enters the BMS of the lithium battery, the external power supply voltage can directly power the BMS, so that the BMS can start working at the moment the external power supply voltage is connected. At the same time, the BMS has a certain screening effect on the external power supply voltage. Only the external power supply voltage that meets the lithium battery charging activation voltage condition will turn on the activation circuit 13.

[0084] It can be seen that a lithium battery BMS provided in the embodiment of the present application includes: a power supply circuit, a voltage stabilizing circuit, a comparison circuit, an activation circuit and a single-chip microcomputer. When an external charging power supply is connected, the power supply circuit 10 processes the voltage and passes it to the voltage stabilizing circuit, so that the voltage stabilizing circuit outputs a reference voltage after voltage division, and the comparison circuit outputs the result of the comparison between the external power supply voltage and the reference voltage to the activation circuit, and the activation circuit outputs an activation signal to the single-chip microcomputer based on the high-level output result, and the single-chip microcomputer activates the entire BMS based on the activation signal to charge the lithium battery. The whole process is completed based on the hardware circuit, and the external power input voltage is processed by the voltage stabilizing circuit to control the voltage input when the lithium battery is charged, and the external power input voltage is screened by the comparison circuit so that the lithium battery charging voltage is within a reasonable charging voltage range. Compared with the scheme of using MCU to realize the charging activation control of the BMS of the lithium battery, the present application greatly reduces the energy consumption and cost investment in the charging activation control process of the BMS of the lithium battery, has a wider range of application scenarios, and has higher charging activation reliability.

[0085] Figure 2 A BMS voltage stabilizing circuit diagram of a lithium battery provided in an embodiment of the present application, such as Figure 2 As shown, this embodiment provides a specific solution, the voltage stabilizing circuit 11 includes: a voltage stabilizer, a first resistor R1, a second resistor R2, a third resistor R3 and a first capacitor C1;

[0086] The cathode of the voltage stabilizer, the second end of the first resistor R1 and the first end of the second resistor R2 are connected, and the common end of the three is used as the output end of the voltage stabilizer circuit 11 to output the reference voltage;

[0087] The reference end of the voltage regulator, the second end of the second resistor R2 and the first end of the third resistor R3 are connected;

[0088] The second end of the third resistor R3 and the first end of the first capacitor C1 are connected to the negative electrode of the battery pack;

[0089] The second end of the first capacitor C1, the first end of the first resistor R1 and the output end V1 of the power circuit are connected.

[0090] like Figure 2As shown, the power circuit output terminal V1 is the voltage signal provided by the power circuit 10 to the voltage stabilizing circuit 11. In actual use, there are multiple voltage levels for charging and discharging lithium batteries. According to product requirements, the resistance values ​​of the second resistor R2 and the third resistor R3 can be adjusted to control the voltage stabilizing circuit 11 to divide the power circuit output terminal V1 to output the reference voltage value of the output terminal Vref. Figure 2 As shown, Figure 2 The intermediate regulator U1 can be a three-terminal adjustable parallel regulator, including a multi-pole amplifier circuit, a bias circuit, a compensation and protection circuit, which enables the regulator U1 to have excellent temperature characteristics and a low temperature drift coefficient through a relatively simple peripheral circuit design, and output a stable reference voltage for the comparison circuit 12.

[0091] It can be seen that in a BMS for a lithium battery provided in an embodiment of the present application, the voltage stabilizing circuit is an indispensable part, which provides a reference voltage for the comparison circuit. The reference voltage is used as a benchmark to enable the BMS to screen the external power supply voltage, thereby improving the probability of charging and activating the lithium battery.

[0092] Figure 3 A BMS comparison circuit diagram of a lithium battery provided in an embodiment of the present application, such as Figure 3 As shown, this embodiment provides a specific solution, the comparison circuit 12 includes: a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a comparator Cmp and a second capacitor C2;

[0093] A first end of the fourth resistor R4 is connected to the positive electrode of the external power supply;

[0094] The second end of the fourth resistor R4 and the first end of the fifth resistor R5 are connected to the same-direction input end of the comparator Cmp;

[0095] The second end of the fifth resistor R5 is connected to the negative electrode of the battery pack;

[0096] A first end of the sixth resistor R6 is connected to the positive power supply end of the comparator Cmp and the output end V1 of the power supply circuit;

[0097] The second end of the sixth resistor R6 is connected to the output end of the comparator Cmp;

[0098] The first end of the second capacitor C2 and the output end of the voltage stabilizing circuit 11 are connected to the inverting input end of the comparator Cmp;

[0099] The second end of the second capacitor C2 and the negative power supply end of the comparator Cmp are connected to the negative electrode of the battery pack.

[0100] like Figure 3As shown, at this time, the power circuit output terminal V1 provided by the power circuit 10 is used as a power supply to the comparator Cmp power supply, and the voltage-stabilized power supply output terminal Vref is used as a signal input terminal to provide a reference voltage for the comparator Cmp. At this time, the external power supply voltage is connected to the same-direction input terminal of the comparator Cmp after being divided by the fourth resistor R4 and the fifth resistor R5, and is compared with the reference voltage output by Vref. When the voltage at the same-direction input terminal of the comparator Cmp is greater than the voltage at the reverse input terminal of the comparator Cmp, that is, the aforementioned external power supply voltage meets the lithium battery charging voltage standard, the output terminal of the comparator Cmp outputs a high level to the activation circuit 13; when the voltage at the same-direction input terminal of the comparator Cmp is less than the voltage at the reverse input terminal of the comparator Cmp, that is, the aforementioned external power supply voltage does not meet the lithium battery charging voltage standard, the output terminal of the comparator Cmp outputs a low level to the activation circuit 13. The sixth resistor R6 limits the current flowing through the output terminal of the comparator Cmp here to prevent the comparator Cmp from being damaged in the event of a short circuit or other abnormal conditions at the output terminal of the comparator Cmp.

[0101] It can be seen that in a BMS for a lithium battery provided in an embodiment of the present application, the comparison circuit determines whether to input the external power supply voltage into the lithium battery for charging by comparing the numerical values ​​of the external power supply voltage after voltage division and the reference voltage provided by the voltage stabilizing circuit, thereby providing a more reliable voltage input for the charging process of the lithium battery and greatly improving the service life of the lithium battery.

[0102] According to the above embodiment, this embodiment provides a specific solution, the activation circuit 13 includes an isolation switch and a first diode D1;

[0103] The control end of the isolating switch is connected to the output end of the comparison circuit 12;

[0104] The first end of the isolation switch is connected to the anode of the first diode D1;

[0105] The second end of the isolation switch is connected to the output end of the battery management chip through the resistor R;

[0106] The cathode of the diode is connected to the single chip computer 14 .

[0107] In this embodiment, the function of the activation circuit 13 is mainly realized by the isolation switch. The output end of the aforementioned comparison circuit 12 is connected to the control end of the isolation switch in the activation circuit 13. When the control end receives a high-level signal, the isolation switch is turned on, and when the control end receives a low-level signal, the isolation switch is turned off. The isolation switch is connected to the single-chip computer 14 through the first diode D1, and the unidirectional conductivity of the diode is used to prevent the pin signal of the single-chip computer 14 from affecting the circuit.

[0108] In a specific embodiment, Figure 4A BMS activation circuit diagram of a lithium battery provided in an embodiment of the present application, such as Figure 4 As shown, the isolation switch is a phototransistor optocoupler, including an infrared emitting diode LED and a phototransistor detector PT;

[0109] The anode of the infrared emitting diode LED is connected to the output end of the comparison circuit 12;

[0110] The cathode of the infrared emitting diode LED is connected to the negative terminal of the battery pack;

[0111] The first end of the phototransistor detector is connected to the single chip microcomputer 14;

[0112] The second terminal of the phototransistor detector is connected to the output terminal of the battery management chip through a resistor.

[0113] In this embodiment, the phototransistor optocoupler has the ability to provide stable signal transmission within a wider voltage range. When the output end of the comparator Cmp provides a voltage greater than the turn-on voltage of the infrared emitting diode LED, the infrared emitting diode LED emits infrared to the phototransistor detector PT, the phototransistor detector PT is turned on, and the output signal of the output end of the battery management chip is transmitted to the microcontroller 14 through the phototransistor detector PT and the first diode D1.

[0114] It can be seen that in a lithium battery BMS provided in an embodiment of the present application, the output end of the comparison circuit is connected to the control end of the isolating switch to control the opening and closing of the isolating switch in the activation circuit. After the isolating switch is opened, there is a reliable insulation gap between the control end of the isolating switch and the closed path of the isolating switch, providing a clearly visible disconnection point. Compared with a non-isolated switch, when the isolating switch is closed, it ensures that the circuit will not damage the microcontroller due to excessive current caused by short circuit or other abnormalities.

[0115] Figure 5 A BMS power supply circuit diagram of a lithium battery provided in an embodiment of the present application, such as Figure 5 As shown, this embodiment provides a specific solution, the power supply circuit 10 includes: a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first capacitor L1, a second capacitor L2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a second diode D2 and a DC-DC chip;

[0116] A first end of the seventh resistor R7 is connected to the positive electrode of the external power supply, and a second end of the seventh resistor R7 is connected to the first end of the first capacitor L1;

[0117] The second end of the first capacitor L1, the input pin of the DC-DC chip, the first end of the eighth resistor R8 and the first end of the third capacitor C3 are connected;

[0118] The second end of the third capacitor C3 is connected to the negative electrode of the battery pack;

[0119] A second end of the eighth resistor R8 is connected to an enable control pin of the DC-DC chip;

[0120] The start pin of the DC-DC chip is connected to the first end of the fourth capacitor C4, and the ground pin of the DC-DC chip is connected to the negative electrode of the battery pack;

[0121] The second end of the fourth capacitor C4, the cathode of the second diode D2, and the first end of the second capacitor L2 are connected to the inductor pin of the DC-DC chip;

[0122] The anode of the second diode D2 is connected to the negative electrode of the battery pack;

[0123] The second end of the second capacitor L2, the first end of the ninth resistor R9, and the first end of the fifth capacitor C5 are connected to the output end V1 of the power supply circuit;

[0124] The second end of the ninth resistor R9 and the first end of the tenth resistor R10 are connected to the output feedback pin of the DC-DC chip;

[0125] A second end of the tenth resistor R10 is connected to the negative electrode of the battery pack.

[0126] In this embodiment, the first capacitor L1 is connected between the DC-DC chip and the external power supply voltage, and plays a role of freewheeling. The seventh resistor R7 plays a current limiting role and is indispensable. The third capacitor C3 plays a buffering role to the ground to prevent the external power supply voltage from damaging the DC-DC chip. The eighth resistor R8, the fourth capacitor C4, the second diode D2 and the second capacitor L2 are all peripheral protection devices of the DC-DC chip, providing a safe and reliable working environment for the DC-DC chip. The DC-DC chip performs a voltage reduction process on the external power supply voltage. The ninth resistor R9 and the tenth resistor R10 serve as the feedback pin resistors of the DC-DC chip. By adjusting the resistance values ​​of the ninth resistor R9 and the tenth resistor R10, the voltage at the output terminal V1 of the output power circuit can be controlled.

[0127] According to the above embodiment, this embodiment provides a specific solution, the power supply circuit 10 further includes: a third diode D3 and a fourth diode D4;

[0128] A common end of the cathodes of the third diode D3 and the fourth diode D4 is connected to the positive electrode of the external power supply;

[0129] A common terminal of anodes of the third diode D3 and the fourth diode D4 is connected to the first terminal of the first capacitor L1 .

[0130] like Figure 5As shown, the third diode D3 and the fourth diode D4 are connected between the external power supply voltage and the DC-DC chip. When the lithium battery supplies power to the external device, due to the unidirectional conductivity of the third diode D3 and the fourth diode D4, the impact of the external device signal on the DC-DC chip is effectively prevented. At the same time, when the lithium battery supplies power to the external device, it plays a freewheeling role.

[0131] According to the above embodiment, this embodiment provides a specific solution, the power supply circuit 10 further includes: a sixth capacitor C6 and a seventh capacitor C7;

[0132] A first end of the sixth capacitor C6 and a first end of the seventh capacitor C7 are connected to the output end V1 of the power supply circuit;

[0133] The second end of the sixth capacitor C6 and the second end of the seventh capacitor C7 are connected to the negative electrode of the battery pack.

[0134] In this embodiment, the sixth capacitor C6 and the seventh capacitor C7 play a filtering role.

[0135] It can be seen that in a BMS for a lithium battery provided in an embodiment of the present application, the power supply circuit is composed of basic components and a simple DC-DC chip, and the voltage at the output terminal V1 of the output power supply circuit can be controlled by adjusting the resistance values ​​of the ninth resistor R9 and the tenth resistor R10.

[0136] Figure 6 A BMS protection circuit diagram of a lithium battery provided in an embodiment of the present application, such as Figure 6 As shown, this embodiment provides a specific solution, further comprising: a protection circuit;

[0137] The protection circuit includes a relay, a transistor, an eleventh resistor R11, a twelfth resistor R12, a fifth diode D5 and an eighth capacitor C8; the relay includes a coil and a single-pole double-gate switch;

[0138] The first end of the single-pole double-gate switch of the relay, the first end of the eighth capacitor C8, and the third voltage-stabilizing source are connected to the positive electrode of the external power supply;

[0139] The second end of the single-pole double-gate switch of the relay and the second end of the eighth capacitor C8 are connected to the input end of the comparison circuit 12;

[0140] The third terminal of the single-pole double-gate switch of the relay is left hanging;

[0141] The first end of the coil of the relay, the second voltage stabilizing source and the cathode of the fifth diode D5 are connected;

[0142] The second end of the coil of the relay, the anode of the fifth diode D5 and the collector of the transistor are connected;

[0143] The base of the transistor, the first end of the twelfth resistor R12 and the second end of the eleventh resistor R11 are connected;

[0144] A first end of the eleventh resistor R11 is connected to a load removal signal terminal of the single chip computer 14;

[0145] A second end of the twelfth resistor R12 and an emitter of the transistor are grounded.

[0146] like Figure 6 As shown, the initial state of the single-pole double-gate switch of the relay is that end 1 is connected to end 2. When there is a short circuit or reverse connection in the circuit of the BMS, the load removal signal end of the microcontroller inputs the SLF_LOD_RVM signal, and the single-pole double-gate switch state of the relay changes to end 1 connected to end 3. Since an arc will be generated during the opening and closing process of the relay, the eighth capacitor C8 is set to be connected to both ends of the relay to protect the circuit safety. The second voltage regulator in the figure is the power supply for the relay, and the setting of the fifth diode D5 can effectively prevent the second voltage regulator from reversely affecting the microcontroller 14.

[0147] It can be seen that in a lithium battery BMS provided in an embodiment of the present application, when the lithium battery BMS is short-circuited or reversely connected, the protection circuit inputs the SLF_LOD_RVM signal from the load removal signal terminal of the single-chip microcomputer to disconnect the external power supply voltage input, which effectively protects the circuit safety of the lithium battery BMS during the charging process.

[0148] The BMS and electrical equipment of the lithium battery provided by the present application are introduced in detail above. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can refer to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can refer to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

[0149] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

Claims

1. A BMS for a lithium battery, characterized in that: include: Power supply circuit, voltage stabilizing circuit, comparison circuit, activation circuit and single chip microcomputer; The input end of the power supply circuit is connected to the positive electrode of the external power supply, and the output end of the power supply circuit is connected to the voltage stabilizing circuit and the comparison circuit, so as to provide an input electrical signal to the voltage stabilizing circuit and power the comparison circuit; The output terminal of the voltage stabilizing circuit is connected to the first input terminal of the comparison circuit, and is used to provide a reference voltage to the comparison circuit; The second input terminal of the comparison circuit is connected to the positive electrode of the external power supply; The output end of the comparison circuit is connected to the activation circuit, and is used to provide the activation circuit with a comparison result of comparing the positive voltage of the external power supply and the reference voltage; The output end of the activation circuit is connected to the single-chip microcomputer, and is used to provide an activation signal to the single-chip microcomputer when the comparison result of the comparison circuit is a high level; The single chip microcomputer is used to activate the entire BMS after receiving the activation signal, so that the lithium battery can be charged.

2. The BMS for lithium battery according to claim 1, characterized in that: The voltage stabilizing circuit comprises: a voltage stabilizer, a first resistor, a second resistor, a third resistor and a first capacitor; The cathode of the voltage stabilizer, the second end of the first resistor and the first end of the second resistor are connected, and the common end of the three is used as the output end of the voltage stabilization circuit to output the reference voltage; The reference end of the voltage regulator, the second end of the second resistor and the first end of the third resistor are connected; The second end of the third resistor and the first end of the first capacitor are connected to the negative electrode of the battery pack; The second end of the first capacitor, the first end of the first resistor and the output end of the power supply circuit are connected.

3. The BMS of the lithium battery according to claim 1, characterized in that: The comparison circuit comprises: a fourth resistor, a fifth resistor, a sixth resistor, a comparator and a second capacitor; The first end of the fourth resistor is connected to the positive electrode of the external power supply; The second end of the fourth resistor and the first end of the fifth resistor are connected to the same-direction input end of the comparator; The second end of the fifth resistor is connected to the negative electrode of the battery pack; The first end of the sixth resistor, the positive power supply end of the comparator and the output end of the power supply circuit are connected; The second end of the sixth resistor is connected to the output end of the comparator; The first end of the second capacitor and the output end of the voltage stabilizing circuit are connected to the inverting input end of the comparator; The second end of the second capacitor and the negative power supply end of the comparator are connected to the negative electrode of the battery pack.

4. The BMS for lithium battery according to claim 1, characterized in that: The activation circuit includes an isolation switch and a first diode; The control end of the isolation switch is connected to the output end of the comparison circuit; The first end of the isolation switch is connected to the anode of the first diode; The second end of the isolation switch is connected to the output end of the battery management chip through a resistor; The cathode of the diode is connected to the single chip computer.

5. The BMS of the lithium battery according to claim 4, characterized in that: The isolating switch is a phototransistor optical coupler, including an infrared emitting diode and a phototransistor detector; The anode of the infrared emitting diode is connected to the output end of the comparison circuit; The cathode of the infrared emitting diode is connected to the negative electrode of the battery pack; The first end of the phototransistor detector is connected to the single chip microcomputer; The second end of the phototransistor detector is connected to the output end of the battery management chip through a resistor.

6. The BMS for lithium battery according to claim 1, characterized in that: The power supply circuit includes: a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first inductor, a second inductor, a third capacitor, a fourth capacitor, a fifth capacitor, a second diode and a DC-DC chip; A first end of the seventh resistor is connected to the positive electrode of the external power supply, and a second end of the seventh resistor is connected to the first end of the first inductor; The second end of the first inductor, the input pin of the DC-DC chip, the first end of the eighth resistor and the first end of the third capacitor are connected; The second end of the third capacitor is connected to the negative electrode of the battery pack; The second end of the eighth resistor is connected to the enable control pin of the DC-DC chip; The start pin of the DC-DC chip is connected to the first end of the fourth capacitor, and the ground pin of the DC-DC chip is connected to the negative electrode of the battery pack; The second end of the fourth capacitor, the cathode of the second diode, and the first end of the second inductor are connected to the inductor pin of the DC-DC chip; The anode of the second diode is connected to the negative electrode of the battery pack; The second end of the second inductor, the first end of the ninth resistor, and the first end of the fifth capacitor are connected to the output end of the power supply circuit; The second end of the ninth resistor and the first end of the tenth resistor are connected to the output feedback pin of the DC-DC chip; The second end of the tenth resistor is connected to the negative electrode of the battery pack.

7. The BMS of the lithium battery according to claim 6, characterized in that: The power supply circuit further includes: a third diode and a fourth diode; A common end of the cathodes of the third diode and the fourth diode is connected to the positive electrode of the external power supply; A common terminal of anodes of the third diode and the fourth diode is connected to the first terminal of the first inductor.

8. The BMS of the lithium battery according to claim 6, characterized in that: The power supply circuit further includes: a sixth capacitor and a seventh capacitor; The first end of the sixth capacitor and the first end of the seventh capacitor are connected to the output end of the power supply circuit; The second end of the sixth capacitor and the second end of the seventh capacitor are connected to the negative electrode of the battery pack.

9. The BMS for lithium batteries according to any one of claims 1 to 8, characterized in that: Also includes: Protection circuit; The protection circuit includes a relay, a triode, an eleventh resistor, a twelfth resistor, a fifth diode and an eighth capacitor; the relay includes a coil and a single-pole double-gate switch; The first end of the single-pole double-gate switch of the relay, the first end of the eighth capacitor, and the third voltage-stabilizing source are connected to the positive electrode of the external power supply; The second end of the single-pole double-gate switch of the relay and the second end of the eighth capacitor are connected to the input end of the comparison circuit; The third end of the single-pole double-gate switch of the relay is suspended; The first end of the coil of the relay, the second voltage stabilizing source and the cathode of the fifth diode are connected; The second end of the coil of the relay, the anode of the fifth diode and the collector of the transistor are connected; The base of the transistor, the first end of the twelfth resistor and the second end of the eleventh resistor are connected; The first end of the eleventh resistor is connected to the load removal signal terminal of the single chip microcomputer; The second end of the twelfth resistor and the emitter of the transistor are grounded.

10. An electrical device, characterized in that: A BMS comprising a lithium battery as claimed in any one of claims 1 to 9.

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