Low-string lithium battery circuit with temperature acquisition and protection functions

Abstract

The present invention discloses a low-string lithium battery circuit with temperature acquisition and protection functions, comprising a battery pack module, a battery protection circuit, a temperature detection circuit, a power control circuit, and a charge and discharge terminal CN. The battery pack module and the temperature detection circuit are both connected to the battery protection circuit, and the temperature detection circuit is connected to the battery protection circuit through the power control circuit. The battery protection circuit and the power control circuit are both connected to the charge and discharge terminal CN. The present invention has low-temperature protection and high-temperature protection, and realizes the temperature protection state of the entire BMS system; the circuit effectively solves the shortcomings of the current low-string lithium battery over-temperature protection solution, reduces the overall cost of the lithium battery pack, and can effectively adjust the over-temperature protection threshold according to different batteries, thereby increasing the safety of the battery during use and avoiding accidents and losses. At the same time, it also has the advantages of low cost and low power consumption.

Description

Technical Field

[0001] The invention relates to a low-string lithium battery circuit with temperature collection and protection functions. Background Art

[0002] With the increasing application of lithium-ion batteries, lithium-ion batteries are increasingly used in power battery systems, such as power tools, vacuum cleaners, etc.; low-string power battery packs have large output power and discharge current, and the discharge of batteries at high and low temperatures will cause irreversible damage to the battery cell body. In order to achieve safe use, it is very important to monitor the temperature of the battery in the lithium battery, so that the entire BMS system can effectively manage the protection circuit and ensure the normal service life and safety performance of the lithium battery.

[0003] Currently, there are temperature protection ICs for low-series lithium battery packs on the market, but there are not many models to choose from, and most of them only have high-temperature protection but no low-temperature protection, which makes it difficult to meet the needs of the general market. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a low-string lithium battery circuit with temperature collection and protection functions.

[0005] In order to achieve the above object, the present invention is achieved through the following technical solutions:

[0006] A low-string lithium battery circuit with temperature collection and protection functions includes a battery pack module, a battery protection circuit, a temperature detection circuit, a power control circuit, and a charge and discharge terminal CN4. The battery pack module and the temperature detection circuit are both connected to the battery protection circuit. The temperature detection circuit is connected to the battery protection circuit through the power control circuit. The battery protection circuit and the power control circuit are both connected to the charge and discharge terminal CN4. The battery pack module is composed of several lithium batteries connected in series.

[0007] Preferably, the charge and discharge terminal CN4 includes a P+ power supply and a P- terminal.

[0008] Preferably, the power control circuit includes a diode D2, a capacitor C18, a MOS tube Q5, a MOS tube Q6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a voltage regulator chip U2, wherein the positive electrode of the diode D2 is connected to the P+ power supply, the negative electrode of the diode D2 is connected to the S electrode of the MOS tube Q5, the S electrode of the MOS tube Q5 is connected to the G electrode of the MOS tube Q5 through the resistor R9, the G electrode of the MOS tube Q5 is connected to the D electrode of the MOS tube Q6 through the resistor R10, the S electrode of the MOS tube Q6 is connected to the ground signal VSS, the G electrode of the MOS tube Q6 is connected to the ground signal VSS through the resistor R8, the G electrode of the MOS tube Q6 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to the battery protection circuit, the D electrode of the MOS tube Q5 is connected to the IN end of the voltage regulator chip U2, the IN end of the voltage regulator chip U2 is connected to the ground signal VSS through the capacitor C18, the G end of the voltage regulator chip U2 is connected to the ground signal VSS, and the OUT end of the voltage regulator chip U2 outputs a 5V power supply.

[0009] Preferably, the power control circuit further includes a capacitor C19 and a capacitor C20, and the OUT terminal of the voltage stabilizing chip U2 is connected to the ground signal VSS via the capacitor C19, and the capacitor C19 is connected in parallel with the capacitor C20.

[0010] Preferably, the temperature detection circuit includes a thermistor RT1, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, an operational amplifier U3A, and an operational amplifier U3B, one end of the resistor R11 is connected to the OUT end of the voltage stabilizing chip U2, the other end of the resistor R11 is connected to the ground signal VSS through the thermistor RT1, the other end of the resistor R11 is marked as SAMP_IN, the other end of the resistor R11 is connected to one end of the resistor R17 through the resistor R16, one end of the resistor R17 is marked as SAMP_H, the other end of the resistor R17 is connected to the ground signal VSS, the same-direction input end of the operational amplifier U3B is connected to the OUT end of the voltage stabilizing chip U2 through the resistor R18, and the same-direction input end of the operational amplifier U3B is connected to the ground signal VSS through the resistor R19. The inverting input terminal of the operational amplifier U3B is connected to one end of the resistor R17, the non-inverting input terminal of the operational amplifier U3B is connected to the output terminal of the operational amplifier U3B through the resistor R20, the output terminal of the operational amplifier U3B is connected to one end of the resistor R21, the other end of the resistor R21 is connected to the battery protection circuit, the other end of the resistor R11 is connected to the non-inverting input terminal of the operational amplifier U3A through the resistor R12, the non-inverting input terminal of the operational amplifier U3A is connected to the ground signal VSS through the resistor R13, the non-inverting input terminal of the operational amplifier U3A is marked as SAMP_L, the non-inverting input terminal of the operational amplifier U3A is connected to the output terminal of the operational amplifier U3A through the resistor R14, the inverting input terminal of the operational amplifier U3A is connected to the non-inverting input terminal of the operational amplifier U3B, the output terminal of the operational amplifier U3A is connected to one end of the resistor R15, and the other end of the resistor R15 is connected to the battery protection circuit.

[0011] Preferably, the battery protection circuit includes a chip U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor RS1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a MOS tube Q1, a MOS tube Q2, a MOS tube Q3, a MOS tube Q4, a fuse F1, and a diode D1. The VDD end of the chip U1 is connected to the ground signal VSS through the capacitor C1, the VC end of the chip U1 is connected to the ground signal VSS through the capacitor C2, and the The VSS terminal is connected to the ground signal VSS, the DO terminal of the chip U1 is connected to the other end of the resistor R7, the DO terminal of the chip U1 is connected to the S pole of the MOS tube Q3, the S pole of the MOS tube Q3 is connected to the G pole of the MOS tube Q3 through the resistor R5, the G pole of the MOS tube Q3 is connected to the other end of the resistor R15, the D pole of the MOS tube Q3 is connected to the S pole of the MOS tube Q4, the S pole of the MOS tube Q4 is connected to the G pole of the MOS tube Q4 through the resistor R6, and the G pole of the MOS tube Q4 is connected to the other end of the resistor R21. The S pole of the MOS tube Q3 is connected to the D pole of the MOS tube Q4 through the diode D1, the D pole of the MOS tube Q4 is connected to the G pole of the MOS tube Q1, the D pole of the MOS tube Q4 is connected to the S pole of the MOS tube Q1 through the resistor R4, the S pole of the MOS tube Q1 is connected to the ground signal VSS through the resistor RS1, the D pole of the MOS tube Q1 is connected to the D pole of the MOS tube Q2, the G pole of the MOS tube Q2 is connected to the CO terminal of the chip U1, the S pole of the MOS tube Q2 is connected to one end of the capacitor C3 through the capacitor C4, and the The other end of the capacitor C3 is connected to the S pole of the MOS tube Q1, the VM end of the chip U1 is connected to the S pole of the MOS tube Q2 through the resistor R3, the VDD end of the chip U1 is connected to one end of the battery pack module through the resistor R1, the VC end of the chip U1 is connected to one end of the battery pack module through the resistor R2, the other end of the battery pack module is connected to the ground signal VSS, one end of the battery pack module is connected to the P+ power supply through the fuse F1, the P+ power supply is connected to one end of the capacitor C5 through the capacitor C6, and the other end of the capacitor C5 is connected to the P- end.

[0012] Preferably, the chip U1 is a Seiko S-8252 series chip.

[0013] The beneficial effects of the present invention are as follows: the present invention collects and compares the resistance value of the thermistor RT1 through a temperature detection circuit, and at the same time confirms the temperature conditions of several lithium batteries in the current battery pack module according to the acquired temperature value to control the MOSFET state, with low temperature protection and high temperature protection, to achieve the temperature protection state of the entire BMS system; the circuit effectively solves the shortcomings of the current low-string lithium battery over-temperature protection solution, reduces the overall cost of the lithium battery pack, and can effectively adjust the over-temperature protection threshold according to different batteries, thereby increasing the safety of the battery during use and avoiding accidents and losses. At the same time, it also has the advantages of low cost and low power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a module connection diagram of the present invention;

[0015] Figure 2 is a circuit schematic diagram of a power supply control circuit;

[0016] Figure 3 It is the circuit schematic diagram of the temperature detection circuit;

[0017] Figure 4 This is the circuit schematic diagram of the battery protection circuit;

[0018] Figure 5 This is the circuit schematic diagram of the battery protection circuit when the battery pack module consists of two lithium batteries. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described below in conjunction with the accompanying drawings:

[0020] Embodiment 1:

[0021] like Figure 1 As shown, a low-string lithium battery circuit with temperature collection and protection functions includes a battery pack module 1, a battery protection circuit 3, a temperature detection circuit 2, a power control circuit 5, and a charge and discharge terminal CN4. The battery pack module 1 and the temperature detection circuit 2 are both connected to the battery protection circuit 3, and the temperature detection circuit 2 is connected to the battery protection circuit 3 through the power control circuit 5. The battery protection circuit 3 and the power control circuit 5 are both connected to the charge and discharge terminal CN4, and the battery pack module 1 is composed of a number of lithium batteries connected in series.

[0022] like Figures 1 to 4 As shown, the charge and discharge terminal CN4 includes a P+ power supply and a P- terminal. The P+ power supply is 6V-8.4V.

[0023] like Figure 2As shown, the power control circuit 5 includes a diode D2, a capacitor C18, a MOS tube Q5, a MOS tube Q6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a voltage stabilizing chip U2. The positive electrode of the diode D2 is connected to the P+ power supply, the negative electrode of the diode D2 is connected to the S electrode of the MOS tube Q5, the S electrode of the MOS tube Q5 is connected to the G electrode of the MOS tube Q5 through the resistor R9, the G electrode of the MOS tube Q5 is connected to the D electrode of the MOS tube Q6 through the resistor R10, and the MOS tube Q The S pole of the MOS tube Q6 is connected to the ground signal VSS, the G pole of the MOS tube Q6 is connected to the ground signal VSS through the resistor R8, the G pole of the MOS tube Q6 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to the battery protection circuit 3, the D pole of the MOS tube Q5 is connected to the IN end of the voltage regulator chip U2, the IN end of the voltage regulator chip U2 is connected to the ground signal VSS through the capacitor C18, the G end of the voltage regulator chip U2 is connected to the ground signal VSS, and the OUT end of the voltage regulator chip U2 outputs a 5V power supply. The model of the voltage regulator chip U2 is SGM2203-5.0, or other LDO chips that can output 5V voltage.

[0024] like Figure 2 As shown, the power control circuit 5 further includes a capacitor C19 and a capacitor C20. The OUT terminal of the voltage stabilizing chip U2 is connected to the ground signal VSS via the capacitor C19. The capacitor C19 is connected in parallel with the capacitor C20.

[0025] like Figure 3As shown, the temperature detection circuit 2 includes a thermistor RT1, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, an operational amplifier U3A, and an operational amplifier U3B. One end of the resistor R11 is connected to the OUT end of the voltage stabilizing chip U2, and the other end of the resistor R11 is connected to the ground signal VSS through the thermistor RT1. The other end of the resistor R11 is marked as SAMP_IN, and the other end of the resistor R11 is connected to one end of the resistor R17 through the resistor R16. One end of the resistor R17 is marked as SAMP_H, and the other end of the resistor R17 is connected to the ground signal VSS. The same-direction input end of the operational amplifier U3B is connected to the OUT end of the voltage stabilizing chip U2 through the resistor R18, and the same-direction input end of the operational amplifier U3B is connected to the ground signal VSS through the resistor R19. The inverting input terminal of the operational amplifier U3B is connected to one end of the resistor R17, the non-inverting input terminal of the operational amplifier U3B is connected to the output terminal of the operational amplifier U3B through the resistor R20, the output terminal of the operational amplifier U3B is connected to one end of the resistor R21, the other end of the resistor R21 is connected to the battery protection circuit 3, the other end of the resistor R11 is connected to the non-inverting input terminal of the operational amplifier U3A through the resistor R12, the non-inverting input terminal of the operational amplifier U3A is connected to the ground signal VSS through the resistor R13, the non-inverting input terminal of the operational amplifier U3A is marked as SAMP_L, the non-inverting input terminal of the operational amplifier U3A is connected to the output terminal of the operational amplifier U3A through the resistor R14, the inverting input terminal of the operational amplifier U3A is connected to the non-inverting input terminal of the operational amplifier U3B, the output terminal of the operational amplifier U3A is connected to one end of the resistor R15, and the other end of the resistor R15 is connected to the battery protection circuit 3.

[0026] like Figure 4As shown, the battery protection circuit 3 includes a chip U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor RS1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3, a MOS transistor Q4, a fuse F1, and a diode D1. The VDD end of the chip U1 is connected to the ground signal VSS through the capacitor C1, the VC end of the chip U1 is connected to the ground signal VSS through the capacitor C2, and the VSS end of the chip U1 is connected to the ground signal VSS. The DO end of the chip U1 is connected to the other end of the resistor R7, the DO end of the chip U1 is connected to the S pole of the MOS tube Q3, the S pole of the MOS tube Q3 is connected to the G pole of the MOS tube Q3 through the resistor R5, the G pole of the MOS tube Q3 is connected to the other end of the resistor R15, the D pole of the MOS tube Q3 is connected to the S pole of the MOS tube Q4, the S pole of the MOS tube Q4 is connected to the G pole of the MOS tube Q4 through the resistor R6, the G pole of the MOS tube Q4 is connected to the other end of the resistor R21, the S pole of the MOS tube Q3 is connected to the G pole of the MOS tube Q4 through the resistor R6, the G pole of the MOS tube Q4 is connected to the other end of the resistor R21, and the S pole of the MOS tube Q3 is connected to the G pole of the MOS tube Q4 through the resistor R21. The pole tube D1 is connected to the D pole of the MOS tube Q4, the D pole of the MOS tube Q4 is connected to the G pole of the MOS tube Q1, the D pole of the MOS tube Q4 is connected to the S pole of the MOS tube Q1 through the resistor R4, the S pole of the MOS tube Q1 is connected to the ground signal VSS through the resistor RS1, the D pole of the MOS tube Q1 is connected to the D pole of the MOS tube Q2, the G pole of the MOS tube Q2 is connected to the CO terminal of the chip U1, the S pole of the MOS tube Q2 is connected to one end of the capacitor C3 through the capacitor C4, and the other end of the capacitor C3 is connected to the S pole of the MOS tube Q1, The VM end of the chip U1 is connected to the S pole of the MOS tube Q2 through the resistor R3, the VDD end of the chip U1 is connected to one end of the battery pack module 1 through the resistor R1, the VC end of the chip U1 is connected to one end of the battery pack module 1 through the resistor R2, the other end of the battery pack module 1 is connected to the ground signal VSS, one end of the battery pack module 1 is connected to the P+ power supply through the fuse F1, the P+ power supply is connected to one end of the capacitor C5 through the capacitor C6, and the other end of the capacitor C5 is connected to the P-end. The model of the chip U1 is the Seiko S-8252 series chip.

[0027] a. Battery pack module; composed of several lithium batteries connected in series;

[0028] b. Battery protection circuit; monitors and protects the charging and discharging voltage and current of the lithium battery in the battery pack module. When the charging and discharging voltage and current of the lithium battery exceed the protection threshold, the charging and discharging Mosfet is disconnected.

[0029] c. Temperature detection circuit: The high and low temperature of the lithium battery is monitored and protected through the thermistor RT1. When the battery temperature exceeds the high and low temperature protection threshold, the discharge MOSFET is cut off to achieve over-temperature protection of the entire battery.

[0030] d. Power control circuit; when the battery is discharged for protection, the power control circuit is cut off and the temperature detection circuit is disabled, so as to realize low power consumption of the entire battery in standby mode.

[0031] e. Charge and discharge terminal CN4: This terminal can be used as both a charging port and a discharging port.

[0032] The connection relationship of each part is as follows: after several lithium batteries are connected in series, each node is connected to the corresponding voltage acquisition circuit of each section in the battery protection circuit, and voltage and current monitoring protection is performed; the output end of the battery protection circuit is connected to the charge and discharge terminal; the input end of the power control circuit is connected to the battery protection circuit and the positive pole of the charge and discharge terminal; the output end of the power control circuit is connected to the temperature detection circuit and supplies power to it; the control end of the temperature detection circuit is connected to the battery protection circuit, and when over-temperature protection occurs, the control signal is output through the control port to control the loop shutdown of the battery protection circuit.

[0033] The temperature acquisition circuit is composed of Figure 3 As shown, it consists of two comparison circuits U3A and U3B and RT1, R11 and other parts, among which R12, R13, R14, R15, U3A and other parts form a low temperature detection circuit; R16, R17, R20, R21, U3B and other parts form a high temperature detection circuit; R18 and R19 divide the 5V voltage in series to provide a 1V reference voltage VERF_1V for the high and low temperature detection circuit.

[0034] like Figure 3As shown, the working process of the low temperature detection circuit is as follows: the thermistor RT1 adopts an NTC with a resistance of 10K at 25℃, and the resistance of the resistor R11 is set to 10K. When the temperature of several lithium batteries in the battery pack module is at room temperature, the 5V voltage is divided in series through the resistor R11 and the resistor RT1, and a sampling input voltage SAMP_IN of about 2.5V can be output; the SAMP_IN voltage is then divided twice through the resistor R12 and the resistor R13 to obtain a low temperature sampling voltage SAMP_L; SAMP_L is connected to the non-inverting input terminal of U3A, and VERF_1V is connected to the inverting input terminal of U3A; at room temperature, the voltage value of SAMP_L is lower than the reference voltage VERF_1V, so the output terminal UTP of the operational amplifier U3A is low level; when the temperature of several lithium batteries in the battery pack module is In a low temperature environment, the resistance of RT1 increases as the temperature decreases, the voltage of SAMP_IN also increases, and the voltage of SAMP_L also increases accordingly. When the voltage of SAMP_L is greater than VERF_1V, the voltage of the in-phase terminal of the U3A op amp is higher than the voltage of the inverting terminal, and the output terminal UTP of U3B is high level; by configuring the resistance of resistors R12 and R13, a low temperature lower limit temperature threshold can be set. When the temperature of several lithium batteries in the battery pack module reaches a certain low temperature value, the voltage of SAMP_L is equal to 1V. When the temperature is lower than this temperature value, UTP outputs a high level trigger signal; the resistor R14 feedback resistor constitutes a hysteresis circuit. Only when the temperature rises to the hysteresis threshold can UTP return to a low level, which can avoid the situation where the temperature jitters at the critical point of the threshold and repeatedly triggers the switch.

[0035] like Figure 3As shown, the working process of the high temperature detection circuit is as follows: the thermistor RT1 uses an NTC with a resistance of 10K at 25℃, and the resistance of the resistor R11 is set to 10K. When the battery core temperature is at room temperature, the 5V voltage is divided in series through R11 and the thermistor RT1 to output a sampling input voltage SAMP_IN of about 2.5V; the SAMP_IN voltage is then divided twice through resistors R16 and R17 to obtain a high temperature sampling voltage SAMP_H; SAMP_H is connected to the reverse input terminal of U3B, and VERF_1V is connected to the non-inverting input terminal of U3B; at room temperature, the voltage value of SAMP_H is higher than the reference voltage VERF_1V, so the output terminal OTP of the operational amplifier U3B is low; when the battery core temperature is at high temperature, The resistance of thermistor RT1 decreases with the increase of temperature, and the voltage value of SAMP_IN also decreases, and the voltage value of SAMP_H also decreases accordingly. When the voltage value of SAMP_H is less than VERF_1V, the voltage of the in-phase terminal of the U3B op amp is higher than the voltage of the inverting terminal, and the output terminal OTP of U3B is high level; by configuring the resistance values ​​of resistors R16 and R17, a high temperature upper limit temperature threshold can be set. When the battery cell temperature reaches a certain high temperature value, the voltage value of SAMP_H is equal to 1V. When the temperature exceeds this temperature value, OTP outputs a high level trigger signal; the R20 feedback resistor constitutes a hysteresis circuit. Only when the temperature drops to the hysteresis threshold can OTP return to a low level, which can avoid the situation where the temperature jitters at the threshold critical point and repeatedly triggers the switch.

[0036] The working process of the power supply control circuit is as follows: Figure 2 , Figure 4As shown, the power control circuit provides a stable 5V working power supply for the temperature detection circuit. When the battery is working normally, the DO terminal of the battery protection circuit U1 outputs a high level. At this time, the G pole of the N-channel MOS tube Q6 is at a high level, and Q6 is in a conducting state. At this time, the G pole of the P-channel MOS tube Q5 is pulled down to a low level through the resistor R10, and Q5 is also in a conducting state. At this time, the P+ power supply is input to the input end of the voltage regulator chip U2 through D2 and Q5, and the 5V voltage regulator power supply is output from the output end of U2 to provide the working voltage for the temperature detection circuit; when the battery is undervoltage or discharge overcurrent occurs When abnormal and protected, the DO terminal of the battery protection circuit U1 outputs a low level, and the G pole of the N-channel MOS tube Q6 is at a low level, and Q6 is in the cut-off state. At this time, the G pole of the P-channel MOS tube Q5 is pulled up to a low level through the R9 resistor, and Q5 is also in the cut-off state. At this time, the P+ power supply cannot be input to the input terminal IN of the voltage regulator chip U2 through Q5, and the output terminal OUT of U2 will not be able to output 5V voltage. The temperature detection circuit stops working when it loses the working voltage, and the entire power control circuit and temperature detection circuit have no current consumption, thereby achieving the purpose of reducing power consumption. When the battery undervoltage or discharge overcurrent protection is released, the DO terminal of U1 is reset to a high level, and the power control circuit and temperature detection circuit also start working again.

[0037] The present invention collects and compares the resistance value of thermistor RT1 through a temperature detection circuit, and at the same time confirms the temperature conditions of several lithium batteries in the current battery pack module according to the acquired temperature value to control the MOSFET state, which has low temperature protection and high temperature protection, and realizes the temperature protection state of the entire BMS system; the circuit effectively solves the shortcomings of the current over-temperature protection scheme of low-string lithium batteries, reduces the overall cost of the lithium battery pack, and can effectively adjust the over-temperature protection threshold according to different batteries, thereby increasing the safety of the battery during use and avoiding accidents and losses. At the same time, it also has the advantages of low cost and low power consumption.

[0038] Embodiment 2:

[0039] like Figure 1 As shown, a low-string lithium battery circuit with temperature collection and protection functions includes a battery pack module 1, a battery protection circuit 3, a temperature detection circuit 2, a power control circuit 5, and a charge and discharge terminal CN4. The battery pack module 1 and the temperature detection circuit 2 are both connected to the battery protection circuit 3, and the temperature detection circuit 2 is connected to the battery protection circuit 3 through the power control circuit 5. The battery protection circuit 3 and the power control circuit 5 are both connected to the charge and discharge terminal CN4, and the battery pack module 1 is composed of two lithium batteries B1 connected in series.

[0040] like Figures 1 to 3 , Figure 5 As shown, the charge and discharge terminal CN4 includes a P+ power supply and a P- terminal. The P+ power supply is 6V-8.4V.

[0041] like Figure 2 As shown, the power control circuit 5 includes a diode D2, a capacitor C18, a MOS tube Q5, a MOS tube Q6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a voltage stabilizing chip U2. The positive electrode of the diode D2 is connected to the P+ power supply, the negative electrode of the diode D2 is connected to the S electrode of the MOS tube Q5, the S electrode of the MOS tube Q5 is connected to the G electrode of the MOS tube Q5 through the resistor R9, the G electrode of the MOS tube Q5 is connected to the D electrode of the MOS tube Q6 through the resistor R10, and the MOS tube Q The S pole of the MOS tube Q6 is connected to the ground signal VSS, the G pole of the MOS tube Q6 is connected to the ground signal VSS through the resistor R8, the G pole of the MOS tube Q6 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to the battery protection circuit 3, the D pole of the MOS tube Q5 is connected to the IN end of the voltage regulator chip U2, the IN end of the voltage regulator chip U2 is connected to the ground signal VSS through the capacitor C18, the G end of the voltage regulator chip U2 is connected to the ground signal VSS, and the OUT end of the voltage regulator chip U2 outputs a 5V power supply. The model of the voltage regulator chip U2 is SGM2203-5.0, or other LDO chips that can output 5V voltage.

[0042] like Figure 2 As shown, the power control circuit 5 further includes a capacitor C19 and a capacitor C20. The OUT terminal of the voltage stabilizing chip U2 is connected to the ground signal VSS via the capacitor C19. The capacitor C19 is connected in parallel with the capacitor C20.

[0043] like Figure 3As shown, the temperature detection circuit 2 includes a thermistor RT1, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, an operational amplifier U3A, and an operational amplifier U3B. One end of the resistor R11 is connected to the OUT end of the voltage stabilizing chip U2, and the other end of the resistor R11 is connected to the ground signal VSS through the thermistor RT1. The other end of the resistor R11 is marked as SAMP_IN, and the other end of the resistor R11 is connected to one end of the resistor R17 through the resistor R16. One end of the resistor R17 is marked as SAMP_H, and the other end of the resistor R17 is connected to the ground signal VSS. The same-direction input end of the operational amplifier U3B is connected to the OUT end of the voltage stabilizing chip U2 through the resistor R18, and the same-direction input end of the operational amplifier U3B is connected to the ground signal VSS through the resistor R19. The inverting input terminal of the operational amplifier U3B is connected to one end of the resistor R17, the non-inverting input terminal of the operational amplifier U3B is connected to the output terminal of the operational amplifier U3B through the resistor R20, the output terminal of the operational amplifier U3B is connected to one end of the resistor R21, the other end of the resistor R21 is connected to the battery protection circuit 3, the other end of the resistor R11 is connected to the non-inverting input terminal of the operational amplifier U3A through the resistor R12, the non-inverting input terminal of the operational amplifier U3A is connected to the ground signal VSS through the resistor R13, the non-inverting input terminal of the operational amplifier U3A is marked as SAMP_L, the non-inverting input terminal of the operational amplifier U3A is connected to the output terminal of the operational amplifier U3A through the resistor R14, the inverting input terminal of the operational amplifier U3A is connected to the non-inverting input terminal of the operational amplifier U3B, the output terminal of the operational amplifier U3A is connected to one end of the resistor R15, and the other end of the resistor R15 is connected to the battery protection circuit 3.

[0044] like Figure 5As shown, the battery protection circuit 3 includes a chip U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor RS1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a MOS tube Q1, a MOS tube Q2, a MOS tube Q3, a MOS tube Q4, a fuse F1, and a diode D1. The VDD end of the chip U1 is connected to the ground signal VSS through the capacitor C1, the VC end of the chip U1 is connected to the ground signal VSS through the capacitor C2, and the VSS end of the chip U1 is connected to the ground signal VSS. The DO end of the chip U1 is connected to the other end of the resistor R7, the DO end of the chip U1 is connected to the S pole of the MOS tube Q3, the S pole of the MOS tube Q3 is connected to the G pole of the MOS tube Q3 through the resistor R5, the G pole of the MOS tube Q3 is connected to the other end of the resistor R15, the D pole of the MOS tube Q3 is connected to the S pole of the MOS tube Q4, the S pole of the MOS tube Q4 is connected to the G pole of the MOS tube Q4 through the resistor R6, the G pole of the MOS tube Q4 is connected to the other end of the resistor R21, the S pole of the MOS tube Q3 is connected to the G pole of the MOS tube Q4 through the diode D1, The D pole of the MOS tube Q4 is connected to the G pole of the MOS tube Q1, the D pole of the MOS tube Q4 is connected to the S pole of the MOS tube Q1 through the resistor R4, the S pole of the MOS tube Q1 is connected to the ground signal VSS through the resistor RS1, the D pole of the MOS tube Q1 is connected to the D pole of the MOS tube Q2, the G pole of the MOS tube Q2 is connected to the CO terminal of the chip U1, the S pole of the MOS tube Q2 is connected to one end of the capacitor C3 through the capacitor C4, the other end of the capacitor C3 is connected to the S pole of the MOS tube Q1, and the VM terminal of the chip U1 is connected to the resistor R 3 is connected to the S pole of the MOS tube Q2. The battery pack module 1 is composed of two lithium batteries B1 connected in series. The VDD end of the chip U1 is connected to one end of the battery pack module 1 through a resistor R1. The VC end of the chip U1 is connected to one end of the battery pack module 1 through a resistor R2. The other end of the battery pack module 1 is connected to the signal VSS. One end of the battery pack module 1 is connected to the P+ power supply through a fuse F1. The P+ power supply is connected to one end of the capacitor C5 through a capacitor C6. The other end of the capacitor C5 is connected to the P-end. The model of the chip U1 is a Seiko S-8252 series chip.

[0045] like Figure 5As shown, two P-channel Q3 and Q4 are connected in series between the discharge tube control terminal DO of the battery protection circuit U1 and the G pole of the discharge MOS tube Q1; wherein the S pole of Q3 is connected to the DO terminal of U1, one end of R5, and the negative pole of the diode D1; the G pole of Q3 is connected to the low temperature protection control output terminal UTP of the temperature detection circuit and the other end of R5; the D pole of Q3 is connected to the S pole of Q4 and one end of R6; the G pole of Q4 is connected to the high temperature protection control output terminal OTP of the temperature detection circuit and the other end of R6; the D pole of Q4 is connected to the G pole of the protection circuit discharge tube Q1, the anode of D1, and one end of R4; the other end of R4 is connected to the S pole of Q1; wherein Q3 and Q4 are temperature protection shutdown MOSFET tubes; R5 and R6 are Q3 and Q4 discharge resistors respectively; R4 is Q1 discharge resistor; diode D1 is a freewheeling diode when Q3 and Q4 are turned off to prevent the instantaneous spike from damaging the MOSFET.

[0046] When the battery operating temperature is normal, the UTP and OTP control signals are both low, at this time Q3 and Q4 are in the on state, and the DO terminal of U1 can normally control the switch state of Q1 through Q3 and Q4; when the battery temperature detection circuit triggers the low temperature protection, UTP outputs a high level, at this time the G pole of Q3 is a high level, Q3 is in the cut-off state, the loop between the DO terminal of U1 and the G pole of Q1 is disconnected, the G pole of Q1 is pulled down to a low level through R4, Q1 is in the cut-off state, and the entire battery will not be able to discharge; when the battery temperature detection circuit triggers the high temperature protection, OTP outputs a high level, at this time the G pole of Q4 is a high level, Q4 is in the cut-off state, the loop between the DO control pin of U1 and the G pole of Q1 is disconnected, the G pole of Q1 is pulled down to a low level through R4, Q1 is in the cut-off state, and the entire battery will not be able to discharge; the control loop between U1 and Q1 is controlled by Q3 and Q4 to control the discharge state of the battery, ensuring the safety and normal use of the lithium battery.

[0047] If charging temperature protection is required, it is only necessary to add a corresponding control MOSFET and temperature detection circuit between the CO terminal of the charging control loop of U1 and the G terminal of Q2.

[0048] The connection relationship of each part is as follows: after several lithium batteries are connected in series, each node is connected to the corresponding voltage acquisition circuit of each section in the battery protection circuit, and voltage and current monitoring protection is performed; the output end of the battery protection circuit is connected to the charge and discharge terminal; the input end of the power control circuit is connected to the battery protection circuit and the positive pole of the charge and discharge terminal; the output end of the power control circuit is connected to the temperature detection circuit and supplies power to it; the control end of the temperature detection circuit is connected to the battery protection circuit, and when over-temperature protection occurs, the control signal is output through the control port to control the loop shutdown of the battery protection circuit.

[0049] The temperature acquisition circuit is composed of Figure 3 As shown, it consists of two comparison circuits U3A and U3B and RT1, R11 and other parts, among which R12, R13, R14, R15, U3A and other parts form a low temperature detection circuit; R16, R17, R20, R21, U3B and other parts form a high temperature detection circuit; R18 and R19 divide the 5V voltage in series to provide a 1V reference voltage VERF_1V for the high and low temperature detection circuit.

[0050] like Figure 3 As shown, the working process of the low temperature detection circuit is as follows: the thermistor RT1 adopts an NTC with a resistance of 10K at 25℃, and the resistance of the resistor R11 is set to 10K. When the temperature of several lithium batteries in the battery pack module is at room temperature, the 5V voltage is divided in series through the resistor R11 and the resistor RT1, and a sampling input voltage SAMP_IN of about 2.5V can be output; the SAMP_IN voltage is then divided twice through the resistor R12 and the resistor R13 to obtain a low temperature sampling voltage SAMP_L; SAMP_L is connected to the non-inverting input terminal of U3A, and VERF_1V is connected to the inverting input terminal of U3A; at room temperature, the voltage value of SAMP_L is lower than the reference voltage VERF_1V, so the output terminal UTP of the operational amplifier U3A is low level; when the temperature of several lithium batteries in the battery pack module is In a low temperature environment, the resistance of RT1 increases as the temperature decreases, the voltage of SAMP_IN also increases, and the voltage of SAMP_L also increases accordingly. When the voltage of SAMP_L is greater than VERF_1V, the voltage of the in-phase terminal of the U3A op amp is higher than the voltage of the inverting terminal, and the output terminal UTP of U3B is high level; by configuring the resistance of resistors R12 and R13, a low temperature lower limit temperature threshold can be set. When the temperature of several lithium batteries in the battery pack module reaches a certain low temperature value, the voltage of SAMP_L is equal to 1V. When the temperature is lower than this temperature value, UTP outputs a high level trigger signal; the resistor R14 feedback resistor constitutes a hysteresis circuit. Only when the temperature rises to the hysteresis threshold can UTP return to a low level, which can avoid the situation where the temperature jitters at the critical point of the threshold and repeatedly triggers the switch.

[0051] like Figure 3As shown, the working process of the high temperature detection circuit is as follows: the thermistor RT1 uses an NTC with a resistance of 10K at 25℃, and the resistance of the resistor R11 is set to 10K. When the battery core temperature is at room temperature, the 5V voltage is divided in series through R11 and the thermistor RT1 to output a sampling input voltage SAMP_IN of about 2.5V; the SAMP_IN voltage is then divided twice through resistors R16 and R17 to obtain a high temperature sampling voltage SAMP_H; SAMP_H is connected to the reverse input terminal of U3B, and VERF_1V is connected to the non-inverting input terminal of U3B; at room temperature, the voltage value of SAMP_H is higher than the reference voltage VERF_1V, so the output terminal OTP of the operational amplifier U3B is low; when the battery core temperature is at high temperature, The resistance of thermistor RT1 decreases with the increase of temperature, and the voltage value of SAMP_IN also decreases, and the voltage value of SAMP_H also decreases accordingly. When the voltage value of SAMP_H is less than VERF_1V, the voltage of the in-phase terminal of the U3B op amp is higher than the voltage of the inverting terminal, and the output terminal OTP of U3B is high level; by configuring the resistance values ​​of resistors R16 and R17, a high temperature upper limit temperature threshold can be set. When the battery cell temperature reaches a certain high temperature value, the voltage value of SAMP_H is equal to 1V. When the temperature exceeds this temperature value, OTP outputs a high level trigger signal; the R20 feedback resistor constitutes a hysteresis circuit. Only when the temperature drops to the hysteresis threshold can OTP return to a low level, which can avoid the situation where the temperature jitters at the threshold critical point and repeatedly triggers the switch.

[0052] The working process of the power control circuit is as follows: Figure 2 , Figure 5As shown, the power control circuit provides a stable 5V working power supply for the temperature detection circuit. When the battery is working normally, the DO terminal of the battery protection circuit U1 outputs a high level. At this time, the G pole of the N-channel MOS tube Q6 is at a high level, and Q6 is in a conducting state. At this time, the G pole of the P-channel MOS tube Q5 is pulled down to a low level through the resistor R10, and Q5 is also in a conducting state. At this time, the P+ power supply is input to the input end of the voltage regulator chip U2 through D2 and Q5, and the 5V voltage regulator power supply is output from the output end of U2 to provide the working voltage for the temperature detection circuit; when the battery is undervoltage or discharge overcurrent occurs When abnormal and protected, the DO terminal of the battery protection circuit U1 outputs a low level, and the G pole of the N-channel MOS tube Q6 is at a low level, and Q6 is in the cut-off state. At this time, the G pole of the P-channel MOS tube Q5 is pulled up to a low level through the R9 resistor, and Q5 is also in the cut-off state. At this time, the P+ power supply cannot be input to the input terminal IN of the voltage regulator chip U2 through Q5, and the output terminal OUT of U2 will not be able to output 5V voltage. The temperature detection circuit stops working when it loses the working voltage, and the entire power control circuit and temperature detection circuit have no current consumption, thereby achieving the purpose of reducing power consumption. When the battery undervoltage or discharge overcurrent protection is released, the DO terminal of U1 is reset to a high level, and the power control circuit and temperature detection circuit also start working again.

[0053] The present invention collects and compares the resistance value of thermistor RT1 through a temperature detection circuit, and at the same time confirms the temperature conditions of several lithium batteries in the current battery pack module according to the acquired temperature value to control the MOSFET state, which has low temperature protection and high temperature protection, and realizes the temperature protection state of the entire BMS system; the circuit effectively solves the shortcomings of the current over-temperature protection scheme of low-string lithium batteries, reduces the overall cost of the lithium battery pack, and can effectively adjust the over-temperature protection threshold according to different batteries, thereby increasing the safety of the battery during use and avoiding accidents and losses. At the same time, it also has the advantages of low cost and low power consumption.

[0054] It should be noted that the above is only a specific embodiment of the present invention. Obviously, the present invention is not limited to the above embodiment, and there are many variations. In short, all variations that can be directly derived or associated with the content disclosed by ordinary technicians in this field should be considered as the protection scope of the present invention.

Claims

1. A low-string lithium battery circuit with temperature acquisition and protection functions, characterized in that: The invention comprises a battery pack module (1), a battery protection circuit (3), a temperature detection circuit (2), a power control circuit (5), and a charge and discharge terminal CN (4); the battery pack module (1) and the temperature detection circuit (2) are both connected to the battery protection circuit (3); the temperature detection circuit (2) is connected to the battery protection circuit (3) via the power control circuit (5); the battery protection circuit (3) and the power control circuit (5) are both connected to the charge and discharge terminal CN (4); and the battery pack module (1) is composed of a plurality of lithium batteries connected in series; The power control circuit (5) comprises a diode D2, a capacitor C18, a MOS tube Q5, a MOS tube Q6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a voltage stabilizing chip U2, wherein the positive electrode of the diode D2 is connected to the P+ power supply, the negative electrode of the diode D2 is connected to the S electrode of the MOS tube Q5, the S electrode of the MOS tube Q5 is connected to the G electrode of the MOS tube Q5 through the resistor R9, the G electrode of the MOS tube Q5 is connected to the D electrode of the MOS tube Q6 through the resistor R10, and the MOS tube Q6 The S pole of the MOS tube Q6 is connected to the ground signal VSS, the G pole of the MOS tube Q6 is connected to the ground signal VSS through the resistor R8, the G pole of the MOS tube Q6 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to the battery protection circuit (3), the D pole of the MOS tube Q5 is connected to the IN end of the voltage stabilizing chip U2, the IN end of the voltage stabilizing chip U2 is connected to the ground signal VSS through the capacitor C18, the G end of the voltage stabilizing chip U2 is connected to the ground signal VSS, and the OUT end of the voltage stabilizing chip U2 outputs a 5V power supply; The power control circuit (5) further comprises a capacitor C19 and a capacitor C20, the OUT terminal of the voltage stabilizing chip U2 is connected to a ground signal VSS via the capacitor C19, and the capacitor C19 is connected in parallel with the capacitor C20; The temperature detection circuit (2) comprises a thermistor RT1, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, an operational amplifier U3A, and an operational amplifier U3B, one end of the resistor R11 is connected to the OUT end of the voltage stabilizing chip U2, the other end of the resistor R11 is connected to the ground signal VSS through the thermistor RT1, the other end of the resistor R11 is marked as SAMP_IN, the other end of the resistor R11 is connected to one end of the resistor R17 through the resistor R16, one end of the resistor R17 is marked as SAMP_H, the other end of the resistor R17 is connected to the ground signal VSS, the same-direction input end of the operational amplifier U3B is connected to the OUT end of the voltage stabilizing chip U2 through the resistor R18, the same-direction input end of the operational amplifier U3B is connected to the ground signal VSS through the resistor R19, and the The inverting input terminal of the operational amplifier U3B is connected to one end of the resistor R17, the non-inverting input terminal of the operational amplifier U3B is connected to the output terminal of the operational amplifier U3B through the resistor R20, the output terminal of the operational amplifier U3B is connected to one end of the resistor R21, the other end of the resistor R21 is connected to the battery protection circuit (3), the other end of the resistor R11 is connected to the non-inverting input terminal of the operational amplifier U3A through the resistor R12, the non-inverting input terminal of the operational amplifier U3A is connected to the ground signal VSS through the resistor R13, the non-inverting input terminal of the operational amplifier U3A is marked as SAMP_L, the non-inverting input terminal of the operational amplifier U3A is connected to the output terminal of the operational amplifier U3A through the resistor R14, the inverting input terminal of the operational amplifier U3A is connected to the non-inverting input terminal of the operational amplifier U3B, the output terminal of the operational amplifier U3A is connected to one end of the resistor R15, and the other end of the resistor R15 is connected to the battery protection circuit (3); The battery protection circuit (3) comprises a chip U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor RS1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a MOS tube Q1, a MOS tube Q2, a MOS tube Q3, a MOS tube Q4, a fuse F1, and a diode D1. The VDD end of the chip U1 is connected to a ground signal VSS through the capacitor C1, the VC end of the chip U1 is connected to a ground signal VSS through the capacitor C2, and the VSS end of the chip U1 is connected to a ground signal VSS through the capacitor C2. The DO end of the chip U1 is connected to the ground signal VSS, the DO end of the chip U1 is connected to the other end of the resistor R7, the DO end of the chip U1 is connected to the S pole of the MOS tube Q3, the S pole of the MOS tube Q3 is connected to the G pole of the MOS tube Q3 through the resistor R5, the G pole of the MOS tube Q3 is connected to the other end of the resistor R15, the D pole of the MOS tube Q3 is connected to the S pole of the MOS tube Q4, the S pole of the MOS tube Q4 is connected to the G pole of the MOS tube Q4 through the resistor R6, the G pole of the MOS tube Q4 is connected to the other end of the resistor R21, and the MOS tube The S pole of Q3 is connected to the D pole of MOS tube Q4 through diode D1, the D pole of MOS tube Q4 is connected to the G pole of MOS tube Q1, the D pole of MOS tube Q4 is connected to the S pole of MOS tube Q1 through resistor R4, the S pole of MOS tube Q1 is connected to the ground signal VSS through resistor RS1, the D pole of MOS tube Q1 is connected to the D pole of MOS tube Q2, the G pole of MOS tube Q2 is connected to the CO terminal of chip U1, the S pole of MOS tube Q2 is connected to one end of capacitor C3 through capacitor C4, and the other end of capacitor C3 is connected to The S pole of the MOS tube Q1 is connected, the VM end of the chip U1 is connected to the S pole of the MOS tube Q2 through a resistor R3, the VDD end of the chip U1 is connected to one end of the battery pack module (1) through a resistor R1, the VC end of the chip U1 is connected to one end of the battery pack module (1) through a resistor R2, the other end of the battery pack module (1) is connected to a ground signal VSS, one end of the battery pack module (1) is connected to a P+ power supply through a fuse F1, the P+ power supply is connected to one end of a capacitor C5 through a capacitor C6, and the other end of the capacitor C5 is connected to a P- end.

2. The low-series lithium battery circuit with temperature collection and protection functions according to claim 1, characterized in that: The charging and discharging terminal CN (4) includes a P+ power supply and a P- terminal.

3. The low-number-of-series lithium battery circuit with temperature acquisition and protection functions according to claim 1, characterized in that: The model of the chip U1 is Seiko S-8252 series chip.

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