Battery management circuit and electric equipment

Abstract

The invention relates to the technical field of vehicle power supply management, and discloses a battery management circuit and electric equipment, the battery management circuit comprises a main positive switch, a main negative switch and a voltage conversion circuit, the voltage conversion circuit comprises a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a transformer and a power supply control chip; the first connecting end of the first switching tube is connected with the positive end of the battery pack, the second connecting end of the first switching tube is connected with the first connecting end of the second switching tube and one end of the transformer, and the second connecting end of the second switching tube is connected with one end of the main negative switch and the negative end of the battery pack; the first connecting end of the third switching tube is connected with the other end of the transformer, and the second connecting end of the third switching tube is connected with the second connecting end of the fourth switching tube and the storage battery; the control end of the third switch tube and the control end of the fourth switch tube are connected with the power supply control chip. The battery pack continuously supplies power to the storage battery, and the situation that electric equipment is difficult to start is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle power management, and in particular to a battery management circuit and power-consuming equipment. Background Art

[0002] As electric vehicles become more intelligent and networked, they are increasingly being equipped with onboard devices, such as cameras, Bluetooth modules, and remote terminals. After an electric vehicle is powered off, some onboard devices need to continue functioning, as they often require functions like sentry mode, welcome mode, remote vehicle search, and remote air conditioning. After the vehicle is powered off, the battery continues to power these devices, but the battery's capacity is limited. Prolonged parking can lead to a depleted battery, making it difficult to start the vehicle. Summary of the Invention

[0003] In view of this, the present invention provides a battery management circuit and an electrical device to solve the problem that a vehicle may be parked for too long, which may cause the battery to be depleted, thereby making it difficult for the electric vehicle to start normally.

[0004] In a first aspect, the present invention provides a battery management circuit, which includes a main positive switch, a main negative switch and a voltage conversion circuit. The voltage conversion circuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a transformer and a power control chip; one end of the main positive switch is connected to the positive end of the battery pack, and one end of the main negative switch is connected to the negative end of the battery pack; the first connection end of the first switch tube is connected to the positive end of the battery pack and one end of the main positive switch, the second connection end of the first switch tube is connected to the first connection end of the second switch tube and one end of the transformer, the second connection end of the second switch tube is connected to one end of the main negative switch and the negative end of the battery pack, the control end of the first switch tube and the control end of the second switch tube are both connected to the power control chip, and the power control chip is communicatively connected to the main control chip of the electrical equipment; the first connection end of the third switch tube is connected to the other end of the transformer, the second connection end of the third switch tube is connected to the second connection end of the fourth switch tube and the battery; the control end of the third switch tube and the control end of the fourth switch tube are both connected to the power control chip, and the first connection end of the fourth switch tube is also connected to the other end of the transformer.

[0005] The battery management circuit provided in this embodiment adds a voltage conversion circuit between the battery pack and the battery. This allows the battery pack to power the battery after a power-consuming device loses power, preventing the device from starting up after a battery is depleted and improving battery safety. Furthermore, by implementing the voltage conversion circuit through a transformer and a switching tube, it can isolate electrical interference between different circuits, block noise transmission between circuits, improve the electromagnetic compatibility of the battery management circuit, and flexibly adjust the voltage based on the switching frequency to accommodate different power requirements. Furthermore, the power control chip and the main control chip can be mutually awakened or put into sleep mode, reducing power consumption while ensuring safety.

[0006] In an optional embodiment, the voltage conversion circuit also includes a first driver chip and a second driver chip; the control end of the first switch tube and the control end of the second switch tube are both connected to the power control chip through the first driver chip, and the control end of the third switch tube and the control end of the fourth switch tube are both connected to the power control chip through the second driver chip; the first driver chip is used to control the on and off of the first switch tube and the second switch tube according to the drive signal generated by the power control chip, and the second driver chip is used to control the on and off of the third switch tube and the fourth switch tube according to the drive signal generated by the power control chip.

[0007] In this embodiment, the power control chip controls the corresponding switch tube through an additional driver chip, which can provide a stronger driving current and reduce the performance requirements of the power control chip.

[0008] In an optional embodiment, the voltage conversion circuit also includes a first capacitor, a second capacitor and a first inductor; one end of the first capacitor is connected to the first connection end of the first switching tube, the other end of the first capacitor is connected to one end of the primary coil in the transformer and one end of the second capacitor, the other end of the second capacitor is connected to the second connection end of the second switching tube, and the other end of the primary coil is connected to the second connection end of the first switching tube and the first connection end of the second switching tube; one end of the secondary coil in the transformer is connected to the first connection end of the third switching tube, the other end of the secondary coil is connected to the first connection end of the fourth switching tube, and the tap of the secondary coil is connected in series with the first inductor and then connected to the positive end of the battery.

[0009] In this embodiment, the first and second capacitors act as energy storage units, rapidly providing or absorbing current at the instant the switch is switched on and off, preventing voltage drops or spikes. The first inductor also acts as an energy storage unit, suppressing output voltage ripple and making the DC output smoother.

[0010] In an optional embodiment, the voltage conversion circuit also includes a third capacitor, a first resistor and a second resistor, and the power control chip also includes a first voltage sampling pin; one end of the third capacitor is connected to the positive terminal of the battery, and the other end of the third capacitor is grounded; one end of the first resistor is connected to the positive terminal of the battery and one end of the third capacitor, the other end of the first resistor is connected to one end of the second resistor and the first voltage sampling pin, and the other end of the second resistor is connected to the second connection end of the third switch tube, the second connection end of the fourth switch tube and the negative terminal of the battery; the first voltage sampling pin is used to detect the output voltage of the voltage conversion circuit, so that the power control chip determines the power level of the battery and adjusts the output voltage of the voltage conversion circuit according to the power level of the battery.

[0011] In this embodiment, obtaining the output voltage of the voltage conversion circuit via the first voltage sampling pin creates a feedback mechanism. This allows the power control chip to adjust the drive signal in real time based on the feedback of the voltage conversion circuit's output voltage, thereby adjusting the switching frequency of the switching transistor to ensure that the output voltage of the voltage conversion circuit is at the target voltage. The power control chip can also determine the battery charge level via the first voltage sampling pin and adjust the output voltage of the voltage conversion circuit accordingly to ensure that the battery is fully charged as quickly as possible while ensuring safety.

[0012] In an optional embodiment, the second connection end of the third switching tube and the second connection end of the fourth switching tube are also connected to the negative end of the vehicle power supply and the ground line of the main control chip, and the tap of the secondary coil is connected in series with the first inductor and is also connected to the positive end of the vehicle power supply and the power supply line of the main control chip.

[0013] In this embodiment, the low voltage output by the voltage conversion circuit and the low voltage provided by the battery can serve as backup for each other. If one fails or becomes incapable of power due to a power shortage, the other can take over and provide the low voltage required by the onboard equipment, thereby supporting normal operation and providing status notifications, giving the user time to respond.

[0014] In an optional embodiment, the battery management circuit also includes a voltage management chip and a pre-charging circuit, the pre-charging circuit includes a first sampling resistor, a fifth switch tube, a freewheeling diode and a second inductor; one end of the first sampling resistor is connected to the positive end of the battery pack and one end of the main positive switch, the other end of the first sampling resistor is connected to the first connection end of the fifth switch tube, the second connection end of the fifth switch tube is connected to one end of the second inductor and the cathode of the freewheeling diode, and the control end of the fifth switch tube is connected to the switch control pin of the voltage management chip; the other end of the second inductor is connected to the other end of the main positive switch, the anode of the freewheeling diode is connected to one end of the main negative switch, and the voltage management chip is communicated with the power control chip and the main control chip.

[0015] This embodiment forms a pre-charging circuit through a first sampling resistor, a fifth switching tube, a freewheeling diode and a second inductor. Compared with the pre-charging circuit composed of a relay and a constant resistor, the switching frequency of the fifth switching tube can be adjusted through the voltage management chip, thereby adjusting the pre-charging current, switching from passive current limiting to active control, and realizing a safer, more efficient and intelligent pre-charging process.

[0016] In an optional embodiment, the battery management circuit also includes a second sampling resistor, and the voltage management chip also includes a first current detection pin and a second current detection pin; the two ends of the first sampling resistor are connected to the first current detection pin, and the two ends of the second sampling resistor are connected to the second current detection pin; the first current detection pin is used to detect the voltage across the first sampling resistor, so that the voltage management chip determines the current of the pre-charging circuit, thereby realizing overcurrent protection for the pre-charging circuit and the voltage conversion circuit; the second current detection pin is used to detect the voltage across the second sampling resistor, so that the voltage management chip determines the current of the main circuit where the battery pack is located, thereby realizing overcurrent protection for the main circuit.

[0017] In an optional embodiment, when the voltage conversion circuit and the pre-charging circuit are working simultaneously, if the current detected by the first current detection pin is greater than the threshold current, the voltage management chip adjusts the current of the pre-charging circuit by controlling the fifth switch tube, and the main control chip adjusts the pre-charging time based on the correspondence between the current of the pre-charging circuit and the pre-charging time until the pre-charging is completed within the preset time period.

[0018] In an optional embodiment, the battery management circuit also includes an insulation detection circuit, the insulation detection circuit includes a first insulation resistor, a second insulation resistor, a fourth capacitor, a fifth capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first switch, a second switch and a third switch, and the voltage management chip also includes an insulation voltage detection pin and a total voltage detection pin; one end of the first insulation resistor is connected to the positive end of the battery pack, the other end of the first insulation resistor is connected to one end of the second insulation resistor, the chassis and one end of the first switch, and the other end of the second insulation resistor is connected to the negative end of the battery pack; one end of the fourth capacitor is connected to the positive end of the battery pack, and the other end of the fourth capacitor is connected to the first insulation resistor. The other end of the insulation resistor, one end of the first switch and one end of the fifth capacitor, the other end of the fifth capacitor is connected to the negative end of the battery pack; one end of the third resistor is connected to the positive end of the battery pack, the other end of the third resistor is connected to one end of the third switch and one end of the fourth resistor, the other end of the fourth resistor is connected to the other end of the first switch and one end of the fifth resistor, the other end of the fifth resistor is connected to one end of the second switch, the other end of the second switch is connected to the insulation voltage detection pin and one end of the sixth resistor, the other end of the sixth resistor is connected to the negative end of the battery pack; one end of the seventh resistor is connected to the positive end of the battery pack, the other end of the seventh resistor is connected to the total voltage detection pin and one end of the eighth resistor, and the other end of the eighth resistor is connected to the negative end of the battery pack.

[0019] In an optional embodiment, the battery management circuit further includes a fuse and a pyrotechnic control switch; one end of the fuse is connected to the positive terminal of the battery pack and one end of the seventh resistor, the other end of the fuse is connected to one end of the pyrotechnic control switch, and the other end of the pyrotechnic control switch is connected to one end of the main positive switch.

[0020] In this embodiment, the fuse can melt to provide protection in the event of overcurrent or short circuit, and the pyrotechnic control switch can be forcibly driven by the controller to disconnect the high-voltage main circuit to provide protection in extreme cases (such as failure of the main positive switch or fuse).

[0021] In an optional embodiment, the battery management circuit further includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor, and the voltage management chip further includes a fuse voltage detection pin, a pyrotechnic control switch voltage detection pin, an output voltage detection pin, and a pyrotechnic control pin; one end of the ninth resistor is connected to the other end of the fuse, the other end of the ninth resistor is connected to one end of the tenth resistor and the fuse voltage detection pin, and the other end of the tenth resistor is connected to the negative end of the battery pack; one end of the eleventh resistor is connected to the other end of the pyrotechnic control switch, the other end of the eleventh resistor is connected to one end of the twelfth resistor and the pyrotechnic control switch voltage detection pin, the other end of the twelfth resistor is connected to the negative end of the battery pack, and the control end of the pyrotechnic control switch is connected to the pyrotechnic control pin; one end of the thirteenth resistor is connected to the other end of the main positive switch, the other end of the thirteenth resistor is connected to one end of the fourteenth resistor and the output voltage detection pin, and the other end of the fourteenth resistor is connected to one end of the main negative switch.

[0022] In this embodiment, the voltage management chip is the core chip of the high-voltage management area, which integrates high-voltage and insulation resistance acquisition, current acquisition, integration and overcurrent protection, control of fireworks control switches, automatic closed-loop control of switch tubes, overcurrent output and communication functions, and has high functional integration.

[0023] In a second aspect, the present invention provides an electrical device, which includes the battery management circuit of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in related technologies, the following briefly introduces the drawings required for use in the specific embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1is a structural diagram of a first battery management circuit according to an embodiment of the present invention;

[0026] Figure 2 is a structural diagram of a second battery management circuit according to an embodiment of the present invention;

[0027] Figure 3 is a structural diagram of a third battery management circuit according to an embodiment of the present invention;

[0028] Figure 4 is a structural diagram of a fourth battery management circuit according to an embodiment of the present invention;

[0029] Figure 5 is a structural diagram of a fifth battery management circuit according to an embodiment of the present invention.

[0030] Figure numerals: 100, voltage conversion circuit; 110, transformer; 120, power control chip; 121, first voltage sampling pin; 130, first driver chip; 140, second driver chip; 200, main control chip; 300, battery; 400, vehicle-mounted power supply; 500, voltage management chip; 600, chassis. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. According to the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of the present invention.

[0032] The present invention provides a battery management circuit and an electrical device. By providing a voltage conversion circuit between a battery pack and a storage battery, the battery pack can continuously supply power to the storage battery after the electrical device is powered off, thereby avoiding the situation where the electrical device is difficult to start after the storage battery is depleted, and improving the safety of the storage battery.

[0033] The battery management circuit can be applied to electrical equipment containing a battery pack (power battery), and the electrical equipment can be an electric vehicle or a backup power supply device, etc.

[0034] The battery management circuit and the electrical equipment provided by the present invention are described in detail below with reference to the accompanying drawings.

[0035] like Figure 1As shown, the battery management circuit includes a main positive switch K1, a main negative switch K2 and a voltage conversion circuit 100. The voltage conversion circuit 100 includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a transformer 110 and a power control chip 120.

[0036] Among them, one end of the main positive switch K1 is connected to the positive terminal PACK+ of the battery pack BAT, one end of the main negative switch K2 is connected to the negative terminal PACK- of the battery pack BAT, one end of the main positive switch K1 is connected to the positive terminal PO+ of the high-voltage output, and the other end of the main negative switch K2 is connected to the negative terminal PO- of the high-voltage output.

[0037] For example, high voltage may refer to a voltage above 48V, and the control end of the main positive switch K1 and the control end of the main negative switch K2 may both be connected to the main control chip 200 of the power-consuming device.

[0038] Specifically, the main control chip 200 can be a control chip of a battery management system (BMS), a microcontroller unit (MCU), or a digital signal processor (DSP). The main control chip 200 is provided with control pins. The main control chip 200 can control the main positive switch K1 to be on or off (conducting or shutting down) through the control pin connected to the control end of the main positive switch K1, and can control the main negative switch K2 to be on or off through the control pin connected to the control end of the main negative switch K2. This can provide power to the subsequent circuit when the power-consuming device is running, or cut off the connection between the battery pack and the subsequent circuit when the power-consuming device is abnormal, thereby preventing damage to the subsequent circuit.

[0039] A first connection end of the first switch tube Q1 is connected to the positive terminal PACK+ of the battery pack BAT and one end of the main positive switch K1. A second connection end of the first switch tube Q1 is connected to the first connection end of the second switch tube Q2 and one end of the transformer 110. A second connection end of the second switch tube Q2 is connected to one end of the main negative switch K2 and the negative terminal PACK- of the battery pack BAT. The control end of the first switch tube Q1 and the control end of the second switch tube Q2 are both connected to the power control chip 120, and the power control chip 120 is communicatively connected to the main control chip 200.

[0040] A first connection end of the third switch tube Q3 is connected to the other end of the transformer 110. A second connection end of the third switch tube Q3 is connected to the second connection end of the fourth switch tube Q4 and the battery 300. A control end of the third switch tube Q3 and a control end of the fourth switch tube Q4 are both connected to the power control chip 120. A first connection end of the fourth switch tube Q4 is also connected to the other end of the transformer 110.

[0041] Specifically, the power control chip 120 is also provided with control pins, and the first switch transistor Q1, the second switch transistor Q2, the third switch transistor Q3, and the fourth switch transistor Q4 can all be connected to the power control chip 120 via the control pins. For example, the power control chip 120 can be a DSP chip or a dedicated switching power supply control chip, which is not specifically limited in the present invention.

[0042] The voltage conversion circuit 100 is used to convert the high voltage across the battery pack to the low voltage required by the battery 300. The low voltage can be, for example, below 24V or below 12V. Specifically, when the power-consuming device is turned off, the main control chip 200 can wake up the power control chip 120. The power control chip 120 generates a drive signal based on the target voltage required by the battery 300. This drive signal is used to control the on and off of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 to adjust the duty cycle of the switches, thereby converting the battery pack voltage to the target voltage, allowing the battery pack to charge the battery 300.

[0043] Specifically, the drive signal generated by the power control chip 120 may be a pulse width modulation (PWM) signal. The target voltage is the charging voltage of the battery 300. For example, when the power consumption device is a passenger vehicle, the target voltage may be within 12V; when the power consumption device is a commercial vehicle, the target voltage may be within 24V. It should be understood that the target voltage can be flexibly changed.

[0044] Among them, after the electric device is turned off, the main control chip 200 can sleep after waking up the power control chip 120. During the operation of the electric device, the power control chip 120 can be in sleep state and the main control chip 200 is in wake-up state.

[0045] Exemplarily, the first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 and the fourth switch tube Q4 may be switching devices such as metal-oxide-semiconductor field-effect transistors (MOS) or triodes. Figure 1 Taking the example of, but not limited to, the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 being N-type MOS transistors, the first connection terminal of the switching transistor may be a drain (D), the second connection terminal of the switching transistor may be a source (S), and the control terminal of the switching transistor may be a gate (G).

[0046] The battery management circuit provided in this embodiment adds a voltage conversion circuit 100 between the battery pack and the battery 300. This allows the battery pack to power the battery 300 after a power-consuming device loses power, preventing the device from starting up after a depleted battery 300 and improving the safety of the battery 300. Furthermore, by implementing the voltage conversion circuit 100 through the transformer 110 and the switching transistor, it can isolate electrical interference between different circuits, block noise transmission between circuits, improve the electromagnetic compatibility of the battery management circuit, and flexibly adjust the voltage based on the switching frequency to meet different power requirements. Furthermore, the power control chip 120 and the main control chip 200 can mutually wake up or put them into sleep mode, reducing power consumption while ensuring safety.

[0047] Furthermore, if Figure 1 As shown, the voltage conversion circuit 100 may further include a first capacitor C1, a second capacitor C2 and a first inductor L1.

[0048] Specifically, one end of the first capacitor C1 is connected to the first connection terminal of the first switching transistor Q1. The other end of the first capacitor C1 is connected to one end of the primary coil of the transformer 110 and one end of the second capacitor C2. The other end of the second capacitor C2 is connected to the second connection terminal of the second switching transistor Q2. The other end of the primary coil is connected to the second connection terminal of the first switching transistor Q1 and the first connection terminal of the second switching transistor Q2. One end of the secondary coil of the transformer 110 is connected to the first connection terminal of the third switching transistor Q3, and the other end of the secondary coil is connected to the first connection terminal of the fourth switching transistor Q4. The second connection terminals of the third switching transistor Q3 and the second connection terminals of the fourth switching transistor Q4 are connected to the negative terminal of the battery 300. The tap of the secondary coil is connected in series with the first inductor L1 and then connected to the positive terminal of the battery 300.

[0049] by Figure 1 For example, the coil on the left side of the transformer 110 is the primary coil, and the coil on the right side is the secondary coil. The tap is a terminal connected at a specific position of the coil. By changing the connection method of the tap, the turns ratio between the primary coil and the secondary coil can be flexibly adjusted, thereby adjusting the output voltage.

[0050] In this embodiment, the first capacitor C1 and the second capacitor C2 act as energy storage units, rapidly providing or absorbing current at the moment the switch is switched on and off, thereby preventing voltage drops or spikes. The first inductor L1 also acts as an energy storage unit, suppressing output voltage ripple and making the DC output smoother.

[0051] Exemplarily, the second connection end of the third switch tube Q3 and the second connection end of the fourth switch tube Q4 are also connected to the negative end of the vehicle power supply 400 and the ground line of the main control chip 200, and the tap of the secondary coil is connected in series with the first inductor L1 and is also connected to the positive end of the vehicle power supply 400 and the power supply line of the main control chip 200.

[0052] In this embodiment, the low voltage output by the voltage conversion circuit and the low voltage provided by the battery can serve as backup for each other. If one fails or becomes incapable of power due to a power shortage, the other can take over and provide the low voltage required by the onboard equipment, thereby supporting normal operation and providing status notifications, giving the user time to respond.

[0053] Alternatively, as Figure 2 As shown, the voltage conversion circuit 100 further includes a first driver chip 130 and a second driver chip 140 .

[0054] Specifically, the control ends of the first switch tube Q1 and the second switch tube Q2 are connected to the power control chip 120 through the first driver chip 130, and the control ends of the third switch tube Q3 and the fourth switch tube Q4 are connected to the power control chip 120 through the second driver chip 140.

[0055] The first driver chip 130 is used to control the on / off of the first switch tube Q1 and the second switch tube Q2 according to the driving signal generated by the power control chip 120 . The second driver chip 140 is used to control the on / off of the third switch tube Q3 and the fourth switch tube Q4 according to the driving signal generated by the power control chip 120 .

[0056] Exemplarily, both the first driver chip 130 and the second driver chip 140 may be isolated MOS driver chips or non-isolated MOS driver chips, which may be determined by designers based on actual needs.

[0057] In this embodiment, the power control chip controls the corresponding switch tube through an additional driver chip, which can provide a stronger driving current and reduce the performance requirements of the power control chip.

[0058] For example, Figure 2 As shown, the voltage conversion circuit 100 may further include a third capacitor C3, a first resistor R1 and a second resistor R2, and the power control chip 120 may further include a first voltage sampling pin 121. The first voltage sampling pin 121 is used to detect the output voltage of the voltage conversion circuit 100, that is, the input voltage of the battery 300, so that the power control chip 120 determines the power level of the battery 300 and adjusts the output voltage of the voltage conversion circuit 100 according to the power level of the battery.

[0059] Specifically, one end of the third capacitor C3 is connected to the positive terminal of the battery 300, and the other end of the third capacitor C3 is grounded. The voltage of the third capacitor C3 can be the voltage U of the battery 300. LVOne end of the first resistor R1 is connected to the positive terminal of the battery 300 and one end of the third capacitor C3, the other end of the first resistor R1 is connected to one end of the second resistor R2 and the first voltage sampling pin 121, and the other end of the second resistor R2 is connected to the second connection end of the third switch tube Q3, the second connection end of the fourth switch tube Q4, and the negative terminal of the battery 300.

[0060] It should be understood that the way in which the power control chip 120 determines the power level of the battery 300 based on the output voltage of the voltage conversion circuit 100 is a conventional way of predicting power level in the art and will not be described in detail here.

[0061] In this embodiment, the output voltage of the voltage conversion circuit 100 is obtained through the first voltage sampling pin 121, and a feedback mechanism can be formed, so that the power control chip 120 can adjust the driving signal in real time based on the feedback output voltage of the voltage conversion circuit 100, and then adjust the switching frequency of the switching tube to ensure that the output voltage of the voltage conversion circuit 100 is the target voltage.

[0062] The power control chip 120 predicts the charge level of the battery 300 based on the sampled value of the first voltage sampling pin 121 and adjusts the output voltage of the voltage conversion circuit 100 according to the charge level of the battery 300. This allows the battery 300 to be fully charged as quickly as possible while ensuring safety. The charge level of the battery 300 can be determined by the state of charge (SOC).

[0063] Specifically, the charging process of the battery 300 can be divided into two stages: constant current charging and constant voltage charging. The switching between the constant current charging stage and the constant voltage charging stage is determined based on the power level of the battery 300. For example, when the power level of the battery 300 is more than 80% of the full power, the constant current charging stage can be switched to the constant voltage charging stage. During the constant current charging stage, the charging current is maintained constant by the voltage conversion circuit 100. At this time, rapid charging at the maximum allowable current can be achieved, shortening the charging time. The terminal voltage of the battery 300 gradually increases as the SOC increases. During the constant voltage charging stage, the charging voltage is maintained constant by the voltage conversion circuit 100. Under constant voltage conditions, the current gradually decreases as the SOC increases to avoid overcharging.

[0064] In some embodiments, as Figure 3 As shown, the battery management circuit further includes a voltage management chip 500 and a pre-charging circuit. The pre-charging circuit includes a first sampling resistor SHUNT1, a fifth switch tube Q5, a freewheeling diode D1 and a second inductor L2.

[0065] Specifically, one end of the first sampling resistor SHUNT1 is connected to the positive terminal PACK+ of the battery pack BAT and one end of the main positive switch K1, the other end of the first sampling resistor SHUNT1 is connected to the first connection end of the fifth switch tube Q5, the second connection end of the fifth switch tube Q5 is connected to one end of the second inductor L2 and the cathode of the freewheeling diode D1, and the control end of the fifth switch tube Q5 is connected to the switch control pin D1 of the voltage management chip 500. Rmos The other end of the second inductor L2 is connected to the other end of the main positive switch K1 , the anode of the freewheeling diode D2 is connected to one end of the main negative switch K2 , and the voltage management chip 500 is in communication with the power control chip 120 and the main control chip 200 .

[0066] The other end of the first sampling resistor SHUNT1 is also connected to the first connection terminal of the first switching transistor Q1 and one end of the first capacitor C1. The second inductor L2 can suppress surge current spikes, smoothing the current rise and reducing the impact on subsequent circuits. When the second inductor L2 turns off the fifth switching transistor Q5, it generates a reverse electromotive force. The freewheeling diode D1 provides a discharge path for the current in the second inductor L2, preventing high-voltage spikes from breaking down the MOS transistor or other components, thereby improving circuit reliability.

[0067] Illustratively, the voltage management chip 500 may be a high-voltage management chip used in the art for performing insulation detection on the battery pack BAT, and the fifth switch tube Q5 may be a switching device such as a MOS tube or a transistor. Figure 3 Taking the fifth switch transistor Q5 as an N-type MOS transistor as an example, but not limited thereto, the first connection terminal of the fifth switch transistor Q5 may be a drain (D), the second connection terminal of the fifth switch transistor Q5 may be a source (S), and the control terminal of the fifth switch transistor Q5 may be a gate (G).

[0068] In this embodiment, the first sampling resistor SHUNT1, the fifth switch tube Q5, the freewheeling diode D1 and the second inductor L2 form a pre-charging circuit. Figure 4 The pre-charging circuit composed of the relay K3 and the constant resistor R0 shown can adjust the switching frequency of the fifth switch tube Q5 through the voltage management chip 500, and then adjust the pre-charging current, switching from passive current limiting to active control, to achieve a safer, more efficient and intelligent pre-charging process.

[0069] Optionally, in order to avoid reverse current backflow, the pre-charging circuit may further include a forward diode connected in series with the second inductor L2.

[0070] In some embodiments, the control terminals of the main positive switch K1 and the main negative switch K2 may also be connected to the control pins of the voltage management chip 500 , and the voltage management chip 500 controls the on and off of the main positive switch K1 and the main negative switch K2 .

[0071] Furthermore, if Figure 3 As shown, the battery management circuit further includes a second sampling resistor SHUNT2 , and the voltage management chip 500 further includes a first current detection pin I1 and a second current detection pin I2 .

[0072] Specifically, both ends of the first sampling resistor SHUNT1 are connected to the first current detection pin I1 , and both ends of the second sampling resistor SHUNT2 are connected to the second current detection pin I2 .

[0073] The first current detection pin I1 is used to detect the voltage across the first sampling resistor SHUNT1, so that the voltage management chip 500 can determine the current of the pre-charging circuit and implement overcurrent protection for the pre-charging circuit and the voltage conversion circuit; the second current detection pin I2 is used to detect the voltage across the second sampling resistor SHUNT2, so that the voltage management chip 500 can determine the current of the main circuit where the battery pack is located and implement overcurrent protection for the main circuit.

[0074] The voltage management chip 500 uses the second current detection pin I2 to monitor the current status of the battery pack's main circuit in real time and implement overcurrent protection for the main circuit. The voltage management chip 500 uses the first current detection pin I1 to detect the current in the pre-charge circuit and the current in the voltage conversion circuit 100, implementing overcurrent protection for both the pre-charge circuit and the voltage conversion circuit 100. Furthermore, the voltage management chip 500 can adjust the output duty cycle of the fifth switch Q5 based on the pre-charge circuit current detected in real time, ensuring that the pre-charge current operates within an appropriate current range.

[0075] Specifically, when the voltage conversion circuit 100 or the pre-charge circuit is operating independently, the current of the first sampling resistor SHUNT1 is collected in real time to control the output current of the load to ensure that no overcurrent occurs during operation. The pre-charge current control is regulated by the switching duty cycle of the fifth switch Q5, while the current of the voltage conversion circuit 100 is regulated by the switching duty cycles of the first switch Q1 and the second switch Q2.

[0076] For example, when the voltage conversion circuit 100 and the pre-charging circuit are working simultaneously, if the current detected by the first current detection pin I1 is greater than the threshold current, the voltage management chip 500 adjusts the current of the pre-charging circuit by controlling the fifth switch tube Q5, and the main control chip 200 adjusts the pre-charging time based on the correspondence between the current of the pre-charging circuit and the pre-charging time until the pre-charging is completed within the preset time period.

[0077] Wherein, threshold current is a current critical value preset. When the actual current in the circuit exceeds the threshold current, the risks such as equipment damage and circuit overheating increase. The corresponding relationship between the current (i.e., pre-charge current) of the pre-charge circuit and the pre-charge time can be configured in advance in the main control chip 200 by the designer. The current of the pre-charge circuit and the pre-charge time are negatively correlated. The larger the current of the pre-charge circuit, the shorter the pre-charge time. The smaller the current of the pre-charge circuit, the longer the pre-charge time.

[0078] That is, when the voltage conversion circuit 100 and the pre-charge circuit are working simultaneously, the voltage conversion circuit 100 is the main one. When an overcurrent occurs, the pre-charge current is limited first to reduce the pre-charge current. The main control chip 200 synchronously extends the pre-charge time according to the relationship between the current size and the pre-charge time until the pre-charge is completed within the specified time. The pre-charge completion status can be judged by the voltage management chip 500 based on the voltage difference across the main positive switch K1. If the pre-charge fails, the pre-charge can be restarted. If the current still exceeds the current threshold after the pre-charge is turned off, the pre-charge is prohibited again. Among them, the current threshold can be determined by the designer based on the needs.

[0079] The current monitoring function enables current data acquisition, overcurrent identification, and current integration. Because overcurrent conditions require high timeliness to ensure battery safety, each current acquisition unit must be paired with at least one overcurrent hardwired output port connected to the power control chip or main control chip. In this embodiment, current sampling inputs and overcurrent outputs at different levels can be added as needed, and other data can be exchanged in real time via communication.

[0080] For example, in order to improve current accuracy and independent current control, a sampling resistor can be arranged in the pre-charging circuit and the voltage conversion circuit 100 respectively and collected by the voltage management chip 500. The sampling resistor of the pre-charging circuit is used to control the pre-charging current and form a closed-loop control with the fifth switch tube Q5, and the sampling resistor of the voltage conversion circuit 100 is used to form a closed-loop control with the first switch tube Q1 and the second switch tube Q2.

[0081] like Figure 5 As shown, the battery management circuit also includes an insulation detection circuit, which includes a first insulation resistor Rx, a second insulation resistor Ry, a fourth capacitor C4, a fifth capacitor C5, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first switch S1, a second switch S2 and a third switch S3. The voltage management chip 500 also includes an insulation voltage detection pin U isoAD and the total voltage detection pin U PACKAD .

[0082] Specifically, taking the electrical equipment as an electric vehicle as an example, the first insulation resistor Rx can be the insulation resistance of the positive terminal PACK+ of the battery pack BAT to the vehicle body, and the second insulation resistor Ry can be the insulation resistance of the negative terminal PACK- of the battery pack BAT to the vehicle body. The first insulation resistor Rx and the second insulation resistor Ry are generally unknown values, and the third resistor R3 to the eighth resistor R8 are generally known values.

[0083] One end of the first insulation resistor Rx is connected to the positive terminal PACK+ of the battery pack BAT. The other end of the first insulation resistor Rx is connected to one end of the second insulation resistor Ry, the chassis 600, and one end of the first switch S1. The other end of the second insulation resistor Ry is connected to the negative terminal PACK- of the battery pack BAT. One end of the fourth capacitor C4 is connected to the positive terminal PACK+ of the battery pack BAT. The other end of the fourth capacitor C4 is connected to the other end of the first insulation resistor Rx, one end of the first switch S1, and one end of the fifth capacitor C5. The other end of the fifth capacitor C5 is connected to the negative terminal PACK- of the battery pack BAT.

[0084] One end of the third resistor R3 is connected to the positive terminal PACK+ of the battery pack BAT, the other end of the third resistor R3 is connected to one end of the third switch S3 and one end of the fourth resistor S4, the other end of the fourth resistor S4 is connected to the other end of the first switch S1 and one end of the fifth resistor R5, the other end of the fifth resistor R5 is connected to one end of the second switch S2, and the other end of the second switch S2 is connected to the insulation voltage detection pin U isoAD and one end of a sixth resistor R6 , and the other end of the sixth resistor R6 is connected to the negative terminal PACK− of the battery pack BAT.

[0085] One end of the seventh resistor R7 is connected to the positive terminal PACK+ of the battery pack BAT, and the other end of the seventh resistor R7 is connected to the total voltage detection pin U PACKAD and one end of the eighth resistor R8, and the other end of the eighth resistor R8 is connected to the negative terminal PACK- of the battery pack BAT.

[0086] Exemplarily, the first switch S1 , the second switch S2 , and the third switch S3 may all be high-voltage isolation switches, such as optocoupler relays, photo-MOS relays, or electromagnetic relays.

[0087] Specifically, for example, in the case of electric vehicles, battery packs typically use high voltage. If the insulation between the high-voltage system and the vehicle body is damaged or destroyed, the insulation performance will be degraded, seriously endangering the safety of the occupants. Therefore, insulation testing of the battery pack is necessary.

[0088] In this embodiment, the third resistor R3 to the sixth resistor R6 form an insulation monitoring loop. By controlling the three switches (the first switch S1, the second switch S2, and the third switch S3), the voltage management chip 500 synchronously collects the insulation detection voltage and the total voltage to calculate the resistance value of the first insulation resistor Rx and the resistance value of the second insulation resistor Ry. isoAD The voltage collected is the total voltage detected by the pin U PACKAD The collected voltage.

[0089] In one example, the voltage management chip 500 first collects and determines the first insulation voltage and the first total voltage after controlling the first switch S1 and the second switch S2 to be closed and the third switch S3 to be open, and then collects and determines the second insulation voltage and the second total voltage after controlling the first switch S1, the second switch S2, and the third switch S3 to be closed.

[0090] The first insulation voltage is the insulation voltage detection pin U after the first switch S1 and the second switch S2 are closed. isoAD The voltage collected is the total voltage detected at the pin U after the first switch S1 and the second switch S2 are closed. PACKAD The collected voltage, the second insulation voltage is the insulation voltage detection pin U after the first switch S1, the second switch S2 and the third switch are all closed. isoAD The collected voltage, the second total voltage is the total voltage detection pin U after the first switch S1, the second switch S2 and the third switch S3 are all closed. PACKAD The collected voltage.

[0091] After obtaining the first insulation voltage, the first total voltage, the second insulation voltage, and the second total voltage, the voltage management chip 500 can calculate the resistance value of the first insulation resistor Rx and the resistance value of the second insulation resistor Ry using the following formulas (1) and (2):

[0092]

[0093] In formula (1), V p Represents the upper arm voltage, V n Represents the lower bridge arm voltage, R x Indicates the resistance of the first insulation resistor Rx, R y represents the resistance of the second insulation resistor Ry, R3 represents the resistance of the third resistor R3, R4 represents the resistance of the fourth resistor R4, R5 represents the resistance of the fifth resistor R5, R6 represents the resistance of the sixth resistor R6, and U p1 represents the first total voltage, and U1 represents the first insulation voltage.

[0094] In formula (2), U p2represents the second total voltage, and U2 represents the second insulation voltage.

[0095] For example, Figure 5 As shown, the battery management circuit further includes a fuse FUSE and a pyrotechnic control switch PSS.

[0096] Specifically, one end of the fuse FUSE is connected to the positive terminal PACK+ of the battery pack BAT and one end of the seventh resistor R7, the other end of the fuse FUSE is connected to one end of the pyrotechnic control switch PSS, the other end of the pyrotechnic control switch PSS is connected to one end of the main positive switch K1, and the control end of the pyrotechnic control switch PSS can be connected to the voltage management chip or the main control chip.

[0097] In this embodiment, the fuse FUSE can melt to provide protection when overcurrent or short circuit occurs, and the pyrotechnic control switch PSS can be forcibly driven by the controller to disconnect the high-voltage main circuit to provide protection in extreme cases (such as failure of the main positive switch K1 or failure of the fuse FUSE).

[0098] In some embodiments, as Figure 5 As shown, the battery management circuit further includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14, and the voltage management chip further includes a fuse voltage detection pin U FUSEAD , Fireworks control switch voltage detection pin U PSSAD , output voltage detection pin U POAD and the fireworks control pin C PSS .

[0099] Specifically, one end of the ninth resistor R9 is connected to the other end of the fuse FUSE, and the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the fuse voltage detection pin U FUSEAD The other end of the tenth resistor R10 is connected to the negative terminal PACK- of the battery pack BAT. One end of the eleventh resistor R11 is connected to the other end of the pyrotechnic control switch PSS. The other end of the eleventh resistor R11 is connected to one end of the twelfth resistor R12 and the pyrotechnic control switch voltage detection pin U PSSAD The other end of the twelfth resistor R12 is connected to the negative terminal PACK- of the battery pack BAT, and the control end of the pyrotechnic control switch PSS is connected to the pyrotechnic control pin C PSS One end of the thirteenth resistor R13 is connected to the other end of the main positive switch K1, and the other end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14 and the output voltage detection pin U POAD The other end of the fourteenth resistor R14 is connected to one end of the main negative switch K2.

[0100] In this embodiment, the ninth resistor R9 to the fourteenth resistor R14 are high voltage sampling circuits at different nodes, which are measured by the voltage management chip. The voltage management chip detects the voltage of the fuse through the fuse voltage detection pin U FUSEAD The terminal voltage of the fuse can be detected and determined, and then the working state of the fuse can be determined to be abnormal. The voltage management chip controls the switch voltage through the pyrotechnics detection pin U PSSAD The terminal voltage of the pyrotechnic control switch can be detected and determined, and then the working state of the pyrotechnic control switch can be determined to be abnormal. The voltage management chip detects the terminal voltage of the pyrotechnic control switch through the output voltage detection pin U POAD The output voltage of the battery pack can be detected and determined, and further, whether there is any abnormality in the working state of the battery pack can be determined.

[0101] In some embodiments, the voltage conversion circuit 100 is further provided with a negative temperature coefficient thermistor (NTC), which is used to collect the temperature of power devices such as the first switch tube Q1 to the fifth switch tube Q5. The voltage management chip 500 is also provided with a temperature detection pin T NTC , negative temperature coefficient thermistor NTC and temperature detection pin T NTC connect.

[0102] Specifically, the voltage management chip 500 can determine the temperature of the power device by measuring the resistance value of the NTC based on a specific resistance-temperature correspondence (usually calibrated and calibrated in advance), and when the temperature exceeds the temperature threshold, timely issue an early warning and take measures (such as adjusting the charging and discharging strategy, starting the cooling system, etc.) to prevent dangerous situations such as thermal runaway.

[0103] For example, in order to avoid long-term leakage of the high-voltage sampling circuit or to achieve isolation from the high voltage, a control switch, such as a MOS tube, may be added to the high-voltage circuit.

[0104] Alternatively, as Figure 5 As shown, the voltage management chip 500 may also include an overcurrent alarm (OCA) and an overcurrent circuit breaker (OCB). When the current in the circuit exceeds a set current threshold, the OCA triggers an alarm signal, notifying the main control chip 200 that there is an overcurrent risk in the circuit so that appropriate protective measures can be taken. When the OCB detects an overcurrent condition, it automatically cuts off the circuit to prevent damage to the battery pack and other circuit components.

[0105] The power control chip 120 may also include an OCB, and the main control chip 200 may also include an OCA. The OCB of the power control chip 120 is connected to the OCB of the voltage management chip 500 , and the OCA of the voltage management chip 500 is connected to the OCA of the main control chip 200 .

[0106] In this embodiment, the voltage management chip 500 is the core chip of the high-voltage management area, which integrates high-voltage and insulation resistance acquisition, current acquisition, integration and overcurrent protection, PSS control, NTC temperature sampling, high-frequency MOS automatic closed-loop control, overcurrent output and communication functions, and has high functional integration.

[0107] Specifically, taking an electric vehicle as an example of an electrical device, the working process of the voltage management circuit provided by the present invention is described in detail.

[0108] After the vehicle is started, the voltage conversion circuit does not work, and the low voltage electricity is supplied by the battery and the vehicle power supply. The main control chip notifies the power control chip to sleep through communication and other means, and the main control chip and the voltage management chip work. The voltage management chip collects the status of the high-voltage area in real time, and the main control chip controls the actions of each actuator according to the real-time data of the high-voltage area and other controller instructions.

[0109] When the detected insulation resistance values ​​(first insulation resistance Rx and second insulation resistance Ry) and the voltages at multiple high-voltage sampling points are normal, the high-voltage device is in a normal state. For example, the main control chip compares the voltages at various high-voltage points to identify that when the main positive switch K1 is disconnected, the voltage at the positive terminal PO+ of the high-voltage output should be 0. However, if the main positive switch K1 is stuck, the voltage may be consistent with the terminal voltage of the pyrotechnic control switch, which can activate the main positive switch K1 / main negative switch K2 to close. During the closing process, the main control chip first outputs a control signal to close the main negative switch K2. After closing, the main chip notifies the voltage management chip to start the pre-charge circuit until the voltage difference before and after the main positive switch K1 reaches a predetermined value. The main chip then closes the main positive switch K1, completes the power-up, stops the pre-charge operation, and turns off the fifth switch Q5. Then, during operation, the current of the second sampling resistor SHUNT2 and the voltages at various high-voltage sampling points are monitored in real time to promptly implement the protection strategy in the event of an abnormality.

[0110] When the vehicle is shut down, the main control chip wakes up the power control chip, which itself goes into hibernation. The power control chip obtains information about each power device, such as voltage, current, and temperature, from the voltage management chip via communication or hardwired signals. This allows the voltage management chip to monitor high-voltage conditions in real time and, in the event of an anomaly, wake up the main control chip to implement protection strategies. The power control chip reads current data, voltage input, and output voltage to control low-voltage safety inputs in real time, powering onboard appliances such as mobile phone chargers and refrigerators, and charging the battery.

[0111] In this embodiment, the high-voltage conversion and on-board power supply conversion components can be powered by a battery for short periods of time, while long-term power supply is provided by two power sources. This significantly reduces the battery capacity, requiring batteries under 10Ah. The voltage management chip operates continuously in both operating states and integrates I1 / I2 in real time, enabling calculation of battery capacity consumption under any power usage conditions, improving battery capacity calculation accuracy.

[0112] The present invention further provides an electrical device, which includes the battery management circuit provided by any of the above embodiments.

[0113] In one example, the electric device may be an electric vehicle.

[0114] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0115] In the description of this specification, the reference terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0116] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0117] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall all fall within the scope defined by the present invention.

Claims

1. A battery management circuit, characterized in that: The battery management circuit includes a main positive switch, a main negative switch and a voltage conversion circuit, and the voltage conversion circuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a transformer and a power control chip; One end of the main positive switch is connected to the positive end of the battery pack, and one end of the main negative switch is connected to the negative end of the battery pack; The first connection end of the first switching tube is connected to the positive end of the battery pack and one end of the main positive switch, the second connection end of the first switching tube is connected to the first connection end of the second switching tube and one end of the transformer, and the second connection end of the second switching tube is connected to one end of the main negative switch and the negative end of the battery pack. The control end of the first switching tube and the control end of the second switching tube are both connected to the power control chip, and the power control chip is communicatively connected to the main control chip of the power-consuming device; The first connection end of the third switching tube is connected to the other end of the transformer, and the second connection end of the third switching tube is connected to the second connection end of the fourth switching tube and the battery; the control end of the third switching tube and the control end of the fourth switching tube are both connected to the power control chip, and the first connection end of the fourth switching tube is also connected to the other end of the transformer.

2. The battery management circuit according to claim 1, characterized in that: The voltage conversion circuit further includes a first driver chip and a second driver chip; The control end of the first switching tube and the control end of the second switching tube are both connected to the power control chip through the first driver chip, and the control end of the third switching tube and the control end of the fourth switching tube are both connected to the power control chip through the second driver chip; The first driver chip is used to control the on and off of the first switch tube and the second switch tube according to the drive signal generated by the power control chip, and the second driver chip is used to control the on and off of the third switch tube and the fourth switch tube according to the drive signal generated by the power control chip.

3. The battery management circuit according to claim 1, characterized in that: The voltage conversion circuit further includes a first capacitor, a second capacitor and a first inductor; One end of the first capacitor is connected to the first connection end of the first switching transistor, the other end of the first capacitor is connected to one end of the primary coil of the transformer and one end of the second capacitor, the other end of the second capacitor is connected to the second connection end of the second switching transistor, and the other end of the primary coil is connected to the second connection end of the first switching transistor and the first connection end of the second switching transistor; One end of the secondary coil in the transformer is connected to the first connection end of the third switching tube, the other end of the secondary coil is connected to the first connection end of the fourth switching tube, and a tap of the secondary coil is connected in series with the first inductor and then connected to the positive terminal of the battery.

4. The battery management circuit according to claim 3, characterized in that: The voltage conversion circuit further includes a third capacitor, a first resistor and a second resistor, and the power control chip further includes a first voltage sampling pin; One end of the third capacitor is connected to the positive terminal of the battery, and the other end of the third capacitor is grounded; One end of the first resistor is connected to the positive terminal of the battery and one end of the third capacitor, the other end of the first resistor is connected to one end of the second resistor and the first voltage sampling pin, and the other end of the second resistor is connected to the second connection end of the third switch tube, the second connection end of the fourth switch tube, and the negative terminal of the battery; The first voltage sampling pin is used to detect the output voltage of the voltage conversion circuit, so that the power control chip determines the power level of the battery and adjusts the output voltage of the voltage conversion circuit according to the power level of the battery.

5. The battery management circuit according to claim 3, characterized in that: The second connection end of the third switching tube and the second connection end of the fourth switching tube are also connected to the negative end of the vehicle-mounted power supply and the ground line of the main control chip. The tap of the secondary coil is connected in series with the first inductor and is also connected to the positive end of the vehicle-mounted power supply and the power supply line of the main control chip.

6. The battery management circuit according to any one of claims 1 to 5, characterized in that: The battery management circuit further includes a voltage management chip and a pre-charging circuit, wherein the pre-charging circuit includes a first sampling resistor, a fifth switch tube, a freewheeling diode and a second inductor; One end of the first sampling resistor is connected to the positive terminal of the battery pack and one end of the main positive switch, the other end of the first sampling resistor is connected to the first connection end of the fifth switch tube, the second connection end of the fifth switch tube is connected to one end of the second inductor and the cathode of the freewheeling diode, and the control end of the fifth switch tube is connected to the switch control pin of the voltage management chip; The other end of the second inductor is connected to the other end of the main positive switch, the anode of the freewheeling diode is connected to one end of the main negative switch, and the voltage management chip is communicatively connected to the power control chip and the main control chip.

7. The battery management circuit according to claim 6, characterized in that: The battery management circuit further includes a second sampling resistor, and the voltage management chip further includes a first current detection pin and a second current detection pin; Two ends of the first sampling resistor are connected to the first current detection pin, and two ends of the second sampling resistor are connected to the second current detection pin; The first current detection pin is used to detect the voltage across the first sampling resistor, so that the voltage management chip determines the current of the pre-charging circuit, thereby realizing overcurrent protection for the pre-charging circuit and the voltage conversion circuit; the second current detection pin is used to detect the voltage across the second sampling resistor, so that the voltage management chip determines the current of the main circuit where the battery pack is located, thereby realizing overcurrent protection for the main circuit.

8. The battery management circuit according to claim 7, characterized in that: When the voltage conversion circuit and the pre-charging circuit are working simultaneously, if the current detected by the first current detection pin is greater than the threshold current, the voltage management chip adjusts the current of the pre-charging circuit by controlling the fifth switch tube, and the main control chip adjusts the pre-charging time based on the correspondence between the current of the pre-charging circuit and the pre-charging time until the pre-charging is completed within the preset time period.

9. The battery management circuit according to claim 6, characterized in that: The battery management circuit further includes an insulation detection circuit, which includes a first insulation resistor, a second insulation resistor, a fourth capacitor, a fifth capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first switch, a second switch, and a third switch. The voltage management chip further includes an insulation voltage detection pin and a total voltage detection pin; One end of the first insulation resistor is connected to the positive terminal of the battery pack, the other end of the first insulation resistor is connected to one end of the second insulation resistor, the chassis and one end of the first switch, and the other end of the second insulation resistor is connected to the negative terminal of the battery pack; One end of the fourth capacitor is connected to the positive terminal of the battery pack, the other end of the fourth capacitor is connected to the other end of the first insulation resistor, one end of the first switch, and one end of the fifth capacitor, and the other end of the fifth capacitor is connected to the negative terminal of the battery pack; One end of the third resistor is connected to the positive terminal of the battery pack, the other end of the third resistor is connected to one end of the third switch and one end of the fourth resistor, the other end of the fourth resistor is connected to the other end of the first switch and one end of the fifth resistor, the other end of the fifth resistor is connected to one end of the second switch, the other end of the second switch is connected to the insulation voltage detection pin and one end of the sixth resistor, and the other end of the sixth resistor is connected to the negative terminal of the battery pack; One end of the seventh resistor is connected to the positive end of the battery pack, the other end of the seventh resistor is connected to the total voltage detection pin and one end of the eighth resistor, and the other end of the eighth resistor is connected to the negative end of the battery pack.

10. The battery management circuit according to claim 9, characterized in that: The battery management circuit also includes a fuse and a pyrotechnic control switch; One end of the fuse is connected to the positive end of the battery pack and one end of the seventh resistor, the other end of the fuse is connected to one end of the pyrotechnic control switch, and the other end of the pyrotechnic control switch is connected to one end of the main positive switch.

11. The battery management circuit according to claim 10, characterized in that: The battery management circuit further includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor, and the voltage management chip further includes a fuse voltage detection pin, a pyrotechnic control switch voltage detection pin, an output voltage detection pin, and a pyrotechnic control pin; One end of the ninth resistor is connected to the other end of the fuse, the other end of the ninth resistor is connected to one end of the tenth resistor and the fuse voltage detection pin, and the other end of the tenth resistor is connected to the negative terminal of the battery pack; One end of the eleventh resistor is connected to the other end of the pyrotechnic control switch, the other end of the eleventh resistor is connected to one end of the twelfth resistor and the voltage detection pin of the pyrotechnic control switch, the other end of the twelfth resistor is connected to the negative terminal of the battery pack, and the control end of the pyrotechnic control switch is connected to the pyrotechnic control pin; One end of the thirteenth resistor is connected to the other end of the main positive switch, the other end of the thirteenth resistor is connected to one end of the fourteenth resistor and the output voltage detection pin, and the other end of the fourteenth resistor is connected to one end of the main negative switch.

12. An electrical device, characterized in that: The electric device comprises the battery management circuit according to any one of claims 1 to 11.

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