Same-port positive end and negative end charging and discharging control circuit of multiple groups of sodium ion batteries

Abstract

The invention provides a same-port positive end and negative end charging and discharging control circuit for multiple groups of sodium ion batteries, which comprises a main charging and discharging loop controlled by an AFE (Active Feedback End) and a secondary protection circuit controlled by a main control MCU (Microprogrammed Control Unit), the secondary protection circuit comprises a secondary protection chip U1 connected with a plurality of sodium ion batteries of the sodium battery module, an MOS tube Q1 connected to the output end of the secondary protection chip U1, a state feedback MOS tube Q4 and a one-time fusing three-terminal fuse F1, and the one-time fusing three-terminal fuse F1 is controlled by the MOS tube Q1 to be fused; and a secondary protection circuit is introduced, so that the safety protection of multiple groups of sodium ion batteries is realized, the use safety of the batteries is enhanced, the problem of high-temperature thermal runaway of the sodium ion batteries is effectively solved, and the low-temperature cruising ability is improved.

Description

Technical Field

[0001] The invention relates to the field of circuits, and in particular to a charge and discharge control circuit for the same positive and negative terminals of multiple groups of sodium ion batteries. Background Art

[0002] Most of the battery management systems on the market are currently designed for lithium batteries. However, the lithium ore resources required for the positive electrode material of lithium-ion batteries are scarce, and the use of lithium-ion batteries themselves has safety risks, especially in high-temperature driving and charging scenarios. There is a great risk of thermal runaway, and the discharge efficiency is low in low-temperature environments below -20°C. In comparison, sodium-ion batteries have a larger internal resistance than lithium-ion batteries, are less likely to produce thermal runaway at high temperatures, have better low-temperature discharge performance, and have a wider discharge voltage platform, with the lowest discharge voltage reaching 2V, so they have better application effects in devices used in outdoor scenarios.

[0003] However, most of the battery management systems on the market are designed for lithium-ion batteries in series, and cannot fully adapt to the management of sodium-ion batteries; although there are a small number of technical studies on battery management of sodium-ion battery packs in series, such as the existing technology such as announcement number CN221531029U, which discloses 5 sodium-ion series protection boards, including battery overcharge and over-discharge protection modules, battery temperature protection modules and battery overcurrent protection modules. This technology is a battery hardware protection solution, but there is an inaccurate battery SOC current estimation. In terms of charging protection, only one protection is considered, and the secondary charging protection in the case of protection chip failure is not considered, which poses a charging risk. For another example, announcement number CN116979659B discloses 15 sodium-ion series BMS protection boards, and the analog front-end chip only performs voltage acquisition, lacks balancing, temperature detection and secondary charging protection functions, and in the case of analog front-end failure, there is a hidden danger of charging protection failure, and this technology can only support the use of 48V sodium battery PACK, and cannot be used for battery protection of more sodium-ion battery packs. Summary of the invention

[0004] The purpose of the present invention is to provide a charge and discharge control circuit for the same positive and negative ends of multiple groups of sodium ion batteries, introduce a secondary protection circuit to achieve safety protection for the multiple groups of sodium ion batteries, and enhance the safety of battery use.

[0005] To achieve the above objectives, the present technical solution provides a common positive terminal charge and discharge control circuit for multiple groups of sodium ion batteries, which is connected between the sodium battery modules of the multiple groups of sodium ion batteries and the load circuit, comprising: A current sampling circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load circuit is used to detect the current between the sodium battery module and the load circuit; The analog front-end chip AFE connected to the sodium battery module and the current sampling circuit is used to collect battery parameter data of the sodium battery module and analyze the battery parameter data to obtain a charge and discharge protection strategy; A main charge and discharge circuit and a main control MCU are communicatively connected to the analog front-end chip AFE, wherein the main charge and discharge circuit includes a charge control circuit and a discharge control circuit connected in series between the positive terminal of the sodium battery module and the load circuit, wherein a MOSFET QC1 is provided on the charge control circuit to control the on and off of the charge path, a MOSFET QC2 is provided on the discharge control circuit to control the on and off of the discharge path, a pre-discharge circuit is connected in parallel to the discharge control circuit, a MOS tube Q5 and a positive temperature coefficient thermistor F2 are provided on the pre-discharge circuit to absorb the instantaneous current of the sodium ion battery module when it is turned on, so as to pre-charge the capacitor on the load circuit and prevent the main discharge circuit MOSFET QC2 from being broken down by the surge current; A secondary protection circuit is communicatively connected to the sodium ion module and the main control MCU, wherein the secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium ion batteries of the sodium battery module, and a MOS tube Q1 connected to the output end of the secondary protection chip U1, a state feedback MOS tube Q4, and a one-time three-terminal fuse F1. The one-time three-terminal fuse F1 is controlled by the MOS tube Q1 at the output end to achieve melting.

[0006] On the other hand, the present invention provides a common negative terminal charge and discharge control circuit for multiple groups of sodium ion batteries, which is connected between the sodium battery modules of the multiple groups of sodium ion batteries and a load circuit, and includes: A current sampling circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load circuit is used to detect the current between the sodium battery module and the load circuit; The analog front-end chip AFE connected to the sodium battery module and the current sampling circuit is used to collect battery parameter data of the sodium battery module and analyze the battery parameter data to obtain a charge and discharge protection strategy; A main charge and discharge circuit and a main control MCU are communicatively connected to the analog front-end chip AFE, wherein the main charge and discharge circuit includes a discharge control circuit and a charge control circuit connected in series between the negative terminal of the sodium battery module and the load circuit, wherein a MOSFET QC1 is provided on the charge control circuit to control the on and off of the charge path, a MOSFET QC2 is provided on the discharge control circuit to control the on and off of the discharge path, a pre-discharge circuit is connected in parallel to the discharge control circuit, a MOS tube Q5 and a positive temperature coefficient thermistor F2 are provided on the pre-discharge circuit to absorb the instantaneous current of the sodium ion battery module when it is turned on; A secondary protection circuit is communicatively connected to the sodium ion module and the main control MCU, wherein the secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium ion batteries of the sodium battery module, and a MOS tube Q1 connected to the output end of the secondary protection chip U1, a state feedback MOS tube Q4, and a one-time three-terminal fuse F1. The one-time three-terminal fuse F1 is controlled by the MOS tube Q1 at the output end to achieve melting.

[0007] Compared with the prior art, this technical solution has the following characteristics and beneficial effects: 1. This solution is designed for the complex scenario of multiple groups of sodium-ion batteries connected in series, and the solution designs a dual mechanism of AFE primary protection and secondary protection. When the AFE chip fails to trigger the overcharge protection due to a fault, the secondary protection circuit monitors the battery voltage in real time through the secondary protection chip U1. Once the overvoltage is triggered, the one-time three-terminal fuse F1 is blown, completely cutting off the charging circuit. Compared with the traditional single-stage protection solution, this design can avoid the risk of battery overcharge explosion caused by AFE failure or charging MOS tube breakdown, and is particularly suitable for the stringent safety requirements of 10-30 strings of high-voltage sodium battery packs.

[0008] 2. In response to the common startup surges, hot-swap spikes, short-circuit shocks and other problems in the application of multiple battery groups in parallel / series, the solution integrates triple protection: pre-discharge circuit: PTC thermistor F2 and MOS tube Q5 are used to achieve instant current limiting at startup to protect the main MOS from being broken down by hundreds of amperes of surges; TVS + capacitor combination: TVS2 is set at the load end to suppress static electricity, and C6 / C7 absorbs hot-swap voltage spikes; reverse freewheeling design: TVS1 guides the residual charge to generate heat during a short circuit to avoid energy backflow and damage to the circuit.

[0009] 3. The same-port charging and discharging architecture is adopted. The AFE chip collects various battery parameter data of multiple groups of sodium-ion batteries in real time to accurately generate charging and discharging protection strategies. With the coordinated control of the main / pre-charging MOS tube, it can achieve: three-level dynamic protection of overcharge / over-discharge / over-current, automatic switching of the main charging circuit and the pre-charging circuit during charging, and synchronous management of the output of multiple groups of batteries during discharging. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a module schematic diagram of the same-port positive terminal control circuit of multiple groups of sodium-ion batteries.

[0011] Figure 2 It is a module schematic diagram of the same-port negative terminal control circuit of multiple groups of sodium-ion batteries.

[0012] Figure 3 It is a circuit diagram of a charging control circuit in a same-port positive and negative terminal control circuit.

[0013] Figure 4 It is a circuit diagram of a discharge control loop in a positive terminal and a negative terminal control circuit of the same port.

[0014] Figure 5 It is a circuit diagram of a pre-discharge circuit in a control circuit of the positive and negative ends of the same port.

[0015] Figure 6 It is a circuit diagram of a secondary protection circuit in the positive and negative terminal control circuit of the same port. DETAILED DESCRIPTION

[0016] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0017] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0018] Embodiment 1 like Figure 1 As shown, the present invention provides a common positive terminal charge and discharge control circuit for multiple groups of sodium ion batteries, which is connected between the sodium battery modules of the multiple groups of sodium ion batteries and the load circuit, and includes: A current sampling circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load circuit is used to detect the current between the sodium battery module and the load circuit; The analog front-end chip AFE connected to the sodium battery module and the current sampling circuit is used to collect battery parameter data of the sodium battery module and analyze the battery parameter data to obtain a charge and discharge protection strategy; A main charge and discharge circuit and a main control MCU are communicatively connected to the analog front-end chip AFE, wherein the main charge and discharge circuit includes a charge control circuit and a discharge control circuit connected in series between the positive terminal of the sodium battery module and the load circuit, wherein a MOSFET QC1 is provided on the charge control circuit to control the on and off of the charge path, a MOSFET QC2 is provided on the discharge control circuit to control the on and off of the discharge path, a pre-discharge circuit is connected in parallel to the discharge control circuit, a MOS tube Q5 and a positive temperature coefficient thermistor F2 are provided on the pre-discharge circuit to absorb the instantaneous current of the sodium ion battery module when it is turned on; A secondary protection circuit is communicatively connected to the sodium ion module and the main control MCU, wherein the secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium ion batteries of the sodium battery module, and a MOS tube Q1 connected to the output end of the secondary protection chip U1, a state feedback MOS tube Q4, and a one-time three-terminal fuse F1. The one-time three-terminal fuse F1 is controlled by the MOS tube Q1 at the output end to achieve melting.

[0019] Regarding the same-port positive terminal control circuit of multiple groups of sodium-ion batteries in this solution, the main charge and discharge circuit is connected in series between the positive terminal of the sodium battery module and the load circuit, and the state of the device is activated or controlled by applying an effective signal to the positive terminal of the sodium battery module and the load circuit.

[0020] The same-port positive terminal control circuit provided in this solution is specifically designed for battery protection of multiple groups of sodium-ion batteries. When the analog front-end chip fails, the secondary protection circuit can be triggered to protect against charging overvoltage and other situations, thereby enhancing the safety of multiple groups of sodium-ion batteries.

[0021] In some embodiments, the main control MCU and the analog front-end chip AFE communicate via I2C, and no communication isolation is required. The main control MCU sends a working instruction to the analog front-end chip AFE to control the analog front-end chip AFE to enter a working state; the analog front-end chip AFE sends feedback information to the main control MCU, wherein the feedback information includes single cell voltage, maximum voltage, minimum voltage, maximum and minimum voltage difference, average voltage value, total voltage, maximum adjacent battery difference, maximum adjacent battery difference channel number, internal temperature, current value, protection state, balance state and other information.

[0022] Regarding the analog front-end chip AFE in the same-port positive terminal control circuit of the multiple groups of sodium-ion batteries: the analog front-end chip AFE enters the working state after obtaining the working instructions of the main control MCU, and then the analog front-end chip AFE collects the battery parameter data of the sodium battery module, and obtains the charging and discharging control signal based on the battery parameter data and analysis.

[0023] In some embodiments, the current sampling circuit includes a resistor R24 ​​and a resistor R25 connected to the AFE chip, a grounding resistor R26, and a current sampling resistor Rshunt1, wherein the current sampling resistor Rshunt1 is connected to the circuit between the sodium battery module and the negative electrode of the load circuit, and the resistor R24 ​​and the grounding resistor R26 are connected to the same point of the circuit between the sodium battery module and the negative electrode of the load circuit, and the point is located on the side of the current sampling resistor Rshunt1 close to the sodium battery module. The current sampling circuit detects the current between the sodium battery module and the load circuit, and sends the current information to the analog front-end chip AFE.

[0024] In some embodiments, the AFE collects battery parameter data of the sodium battery module including battery SOC, SOH, total voltage, single cell voltage, charge and discharge current, battery pack temperature, charging MOS status, and discharging MOS status, and correspondingly analyzes the charge and discharge control signals of the battery parameter data. The corresponding charge and discharge protection strategies generated include at least one of single cell overvoltage protection, single cell undervoltage protection, charge and discharge overcurrent protection, short circuit protection, overtemperature protection, charging low temperature protection, and charging timeout protection.

[0025] In some embodiments, the same positive terminal control circuit of multiple groups of sodium ion batteries in this solution can also absorb spikes during hot plugging and unplugging. Specifically, in this solution, capacitors C6 and C7 are connected in series between the positive electrode P+ / C+ and the negative electrode P- / C- of the load circuit, and capacitors C6 and C7 can absorb the voltage spikes generated instantly when the load of the load circuit is plugged in with power on.

[0026] In some embodiments, the same positive terminal control circuit of multiple groups of sodium ion batteries in this solution can also realize the electrostatic protection during charging and discharging hot plugging. Specifically, this solution connects a bidirectional transient voltage suppression diode TVS2 in series between the positive electrode P+ / C+ and the negative electrode P- / C- of the load circuit to suppress the absorption of static electricity.

[0027] In some embodiments, the same-port positive terminal control circuit of multiple groups of sodium-ion batteries in this scheme can also realize the positive and negative short-circuit continuous current protection of the load circuit. Specifically, in this scheme, an ordinary Schottky diode TVS1 is connected in series between the positive electrode P+ / C+ and the negative electrode P- / C- of the load circuit, and the ordinary Schottky diode TVS1 is reversely connected in parallel to the load circuit. Correspondingly, the polarity of the load circuit is set to be positive at the top and negative at the bottom when the load is in normal operation, and when the positive and negative electrodes of the load circuit are short-circuited, a large current will be generated, and the large current will flow through the MOSFET QC1 set on the charging control circuit and the MOSFET QC2 set on the discharge control circuit, so that the MOSFET QC1 and the MOSFET QC2 are immediately turned off. At this time, the polarity of the load circuit is changed to negative at the top and positive at the bottom, and the retained charge is consumed by the ordinary Schottky diode TVS1 continuous current in the load circuit to generate heat, so as to prevent the peak energy when the load circuit is short-circuited from entering the transient voltage suppression diode TVS2 or the capacitor C6 or the capacitor C7.

[0028] Regarding the charging control circuit of this solution, the structure is as follows Figure 3 As shown: In some embodiments, the charging control circuit includes a MOSFET QC1 arranged in a circuit between the positive terminal of the sodium battery module and the load circuit, and a capacitor C1 and a capacitor C2 connected in series between the S pole and the D pole of the MOSFET QC1, wherein the G pole and the D pole of the MOSFET QC1 are connected to the primary charging control circuit, the S pole of the MOSFET QC1 is connected to the No. 3 pin of the one-time three-terminal fuse F1, and the D pole is connected to the D pole of the MOSFET QD1, wherein a voltage stabilizing diode ZD1 and a resistor R1 are connected in parallel between the D pole of the MOSFET QC1 and the primary charging control circuit, and the resistor R1 is connected in series with a resistor R5 and then connected to the D pole of the MOS tube Q2 of the primary charging control circuit, the G pole of the MOS tube Q2 is connected to the AFE chip through a resistor R7, and a resistor R6 is connected in parallel between the S pole of the MOS tube Q2 and the G pole of the MOS tube Q2, and the S pole of the MOS tube Q2 is grounded.

[0029] Regarding the discharge control circuit of this scheme, the structure is as follows Figure 4 As shown: In some embodiments, the discharge control loop includes a MOSFET QD1 arranged in a circuit between a sodium battery module and a positive electrode of a load loop, and a capacitor C3 and a capacitor C4 connected in series between a source and a drain of the MOSFET QD1, wherein a G pole and an S pole of the MOSFET QD1 are connected to a primary discharge control loop, a D pole of the MOSFET QD1 is connected to a D pole of the MOSFET QC1, an S pole of the MOSFET QD1 is connected to a positive pole of the load loop, an S pole of the MOS tube Q3 is grounded, a voltage stabilizing diode ZD2 and a resistor R2 are connected in parallel between the S pole of the MOSFET QD1 and the primary discharge control loop, and the resistor R2 is further connected in series with a resistor R8 to be connected to the D pole of the MOS tube Q3 of the primary discharge control loop, a G pole of the MOS tube Q3 is connected to an AFE chip through a resistor R10, a resistor R9 is connected in series between the G pole of the MOS tube Q3 and the S pole of the MOS tube Q3, and the S pole of the MOS tube Q3 is grounded.

[0030] When the analog front-end chip AFE obtains the battery parameter data and determines that the voltage of the current sodium-ion battery module triggers the first-level charging protection threshold, the charging and discharging protection strategy of the single-cell overvoltage protection in response to the overcharge protection is triggered. At this time, the MOSFET QC1 is turned off and the MOSFET QD1 is kept open, the charging is cut off and the current of the sodium-ion battery pack is powered to the load circuit through the body diode in the MOSFETQC1. Furthermore, when the current sampling circuit detects that the current exceeds 300mA, the MOSFET QC1 is reopened to end the charging cutoff protection to reduce heat generation.

[0031] When the analog front-end chip AFE obtains the battery parameter data and determines that the voltage of the current sodium-ion battery module touches the over-discharge protection threshold, the charge and discharge protection strategy of the single-cell undervoltage protection in response to the over-discharge protection is triggered. At this time, the MOSFET QD1 is turned off and the MOSFET QC1 is kept open, the main charge and discharge circuit is disconnected to supply power to the load circuit, and at the same time, the external charger connected between the positive terminal and the negative terminal of the load circuit charges the sodium-ion battery pack, and the current passes through the body diode in the MOSFET QD1 to the positive electrode of the sodium-ion battery pack. Further, when the current sampling circuit detects that the current exceeds 300mA, the MOSFET QD1 is turned on to end the discharge cut-off protection to reduce heat generation. Further, when the analog front-end chip AFE obtains the battery parameter data and determines that the current of the current sodium-ion battery module exceeds the current protection threshold during the charge and discharge process, the charge and discharge protection strategy of the over-current protection in response to the over-current protection is triggered. At this time, the MOSFET QD1 and the MOSFET QC1 are turned off, and the positive electrode of the sodium-ion battery pack is completely disconnected from the subsequent charger or load.

[0032] Regarding the pre-discharge circuit of this scheme, the structure is as follows Figure 5As shown: In some embodiments, the pre-discharge circuit includes a MOS tube Q5 and a positive temperature coefficient thermistor F2 connected in parallel to the discharge control circuit, wherein the D pole of the MOS tube Q5 is connected to the first pin of the positive temperature coefficient thermistor F2, the second pin of the positive temperature coefficient thermistor F2 is connected to the negative terminal of the load circuit, the S pole of the MOS tube Q5 is connected to the other end of the pre-discharge circuit, the S pole of the MOS tube Q5 is connected to the G pole of the MOS tube Q5 through the resistor R21 and the voltage regulator diode Z2, and the G pole of the MOS tube Q5 is connected to the collector of the triode Q6 through the resistor R23, the emitter of the triode Q6 is grounded, and the base of the triode Q6 is connected to the main control MCU through the resistor R20 for communication, and is grounded through the resistor R22.

[0033] Since the input end of the load's electronic control is equipped with a large capacitor, the sodium-ion battery pack's BMS will have several hundred amperes of instantaneous current entering the large capacitor at the moment of startup. In this way, the MOSFET QD1 and MOSFET QC1 of the main charge and discharge circuit will be at great risk and easily broken down. To avoid MOS damage, when the sodium-ion battery pack's BMS is turned on, the main control MCU controls the MOS tube Q5 to turn on for a period of time. At this time, the instantaneous large current passes through the MOS tube Q5 and is absorbed and limited by the positive temperature coefficient thermistor F2. After the large capacitor of the electronic control is fully charged, the AFE is triggered to turn on the MOSFET QD1 and turn off the MOS tube Q5, which can play a role in pre-charging when the power is turned on.

[0034] Regarding the secondary protection circuit of this solution, the structure is as follows Figure 6 As shown: The secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium ion batteries of the sodium battery module, and a MOS tube Q1, a state feedback MOS tube Q4, and a one-time three-terminal fuse F1 connected to the output end of the secondary protection chip U1. Further, the output end of the secondary protection chip U1 is connected to the G pole of the state feedback MOS tube Q4 through a resistor R17, the S pole of the state feedback MOS tube Q4 is grounded, the D pole of the state feedback MOS tube Q4 is feedback signal through R19 and is connected to the main control MCU for communication, the output end of the secondary protection chip U1 is connected to the G pole of the MOS tube Q1 through a resistor R3, the D pole of the MOS tube Q1 is connected to the No. 2 pin of the one-time three-terminal fuse F1, the S pole of the MOS tube Q1 is grounded, and the S pole and the D pole of the MOS tube Q1 are connected in parallel through a voltage stabilizing diode ZD1 and a capacitor C5, respectively, the No. 1 pin of the one-time three-terminal fuse F1 is connected to the positive pole of the sodium battery module, and the No. 3 pin is connected to the MOSFET QC1.

[0035] When the sodium-ion battery pack is in a normal charging state, the output end of the secondary protection chip U1 outputs a low level by default. At this time, the D pole and S pole of the MOS tube Q1 are disconnected, and the corresponding pins 1 and 3 of the one-time three-terminal fuse F1 are turned on, and the pin 2 is left floating. At this time, the main control MCU sends an instruction to the analog front-end chip AFE to generate a charging signal to start the normal charging process. The analog front-end chip AFE controls the D pole of the MOS tube Q2 to be turned on to the ground, so that the G pole of the MOSFET QC1 is turned on to the ground, and the D pole and S pole of the MOSFET QC1 are turned on to make the MOSFET QC1 in an turned-on state; at the same time, the analog front-end chip AFE controls the MOS tube Q3 to be turned on, so that the G pole of the MOSFET QD1 is turned on to the ground through the MOS tube Q3, and the MOSFET QD1 is turned on, so that the charging current flows from the positive pole of the load circuit through the MOSFET QD1, the MOSFET QC1 and the one-time three-terminal fuse F1 to the sodium-ion battery pack. When the sodium-ion battery pack is fully charged and the voltage triggers the overcharge first-level protection threshold, an overcharge protection signal is generated to turn off the MOSFET QC1 realizes battery protection.

[0036] When the analog front-end chip AFE fails to operate, the overcharge protection signal cannot be triggered after the battery of the sodium-ion battery pack is fully charged, and the MOSFET QC1 remains in the on state. At this time, the current of the external load continues to charge the battery of the sodium-ion battery pack. When the battery voltage continues to rise to trigger the secondary protection threshold, the output terminal C0 of the secondary protection chip U1 outputs a high level, turns on the MOS tube Q1 so that the D pole of the MOS tube Q1 is connected to the ground, and the current of the positive electrode of the sodium-ion battery pack flows from the No. 1 pin of the one-time three-terminal fuse F1 to GND, and instantly heats and fuses to protect the battery from continuous overcharging. At the same time, the secondary protection chip U1 controls the MOS tube Q4 to be connected to the ground, and the T0_MCU signal becomes a low level to notify the main control MCU that the one-time three-terminal fuse has been blown.

[0037] The same-port positive terminal control circuit for multiple groups of sodium-ion batteries provided in this solution can provide a MOS control BMS solution for the positive and negative terminals of a sodium-ion battery group of 10 to 30 strings of sodium-ion batteries, and the secondary protection circuit can make up for the shortcomings when the AFE fails and the charging protection MOS fails.

[0038] Embodiment 2 like Figure 2 As shown, the present solution provides a common negative terminal control circuit for multiple groups of sodium ion batteries, connected between the sodium battery modules of the multiple groups of sodium ion batteries and the load circuit, including: A current sampling circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load circuit is used to detect the current between the sodium battery module and the load circuit; An analog front-end chip AFE connected to a sodium battery module and a current sampling circuit, which is used to collect battery parameter data of the sodium battery module and analyze the battery parameter data to obtain a charge and discharge protection strategy; A main charge and discharge circuit and a main control MCU communicatively connected to the analog front-end chip AFE. The main charge and discharge circuit includes a discharge control circuit and a charge control circuit connected in series between the negative terminal of the sodium battery module and the load circuit. A MOSFET QC1 is provided on the charge control circuit to control the on and off of the charge path, and a MOSFET QC2 is provided on the discharge control circuit to control the on and off of the discharge path. A pre-discharge circuit is connected in parallel to the discharge control circuit. A MOS transistor Q5 and a positive temperature coefficient thermistor F2 are provided on the pre-discharge circuit to absorb the instantaneous current when the sodium ion battery module is powered on; A secondary protection circuit communicatively connected to the sodium ion module and the main control MCU. The secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium ion batteries of the sodium battery module, and a MOS transistor Q1, a status feedback MOS transistor Q4, and a one-time fuse three-terminal fuse F1 connected to the output terminal of the secondary protection chip U1. The one-time fuse three-terminal fuse F1 is controlled by the MOS transistor Q1 at the output terminal to achieve fusing.

[0039] It should be noted that the difference between the same-port negative terminal control circuit of the multiple groups of sodium ion batteries and the same-port positive terminal control circuit of the multiple groups of sodium ion batteries is that the charge control circuit and the discharge control circuit on the main charge and discharge circuit are connected in series between the negative terminal of the sodium battery module and the load circuit, and the state of the device is activated or controlled by applying an effective signal to the negative terminal of the sodium battery module and the load circuit. Therefore, the content same as that in Embodiment 1 will not be repeated here, and only the differences will be described below: In some embodiments, an isolation circuit module is additionally added to the part where the main control MCU communicates with the outside to prevent the high voltage generated by the load from damaging the MCU communication pin when the negative terminal MOS is turned off.

[0040] Regarding the discharge control circuit of this solution: In some embodiments, the discharge control loop includes a MOSFET QD1 arranged in a circuit between a sodium battery module and a negative electrode of a load loop, and a capacitor C3 and a capacitor C4 connected in series between a source and a drain of the MOSFET QD1, wherein a G pole and an S pole of the MOSFET QD1 are connected to a primary discharge control loop, a D stage of the MOSFET QD1 is connected to an output end of a current sampling circuit, an S pole of the MOSFET QD1 is connected to a negative electrode terminal of the load loop, an S pole of the MOS tube Q3 is grounded, a voltage stabilizing diode ZD2 and a resistor R2 are connected in parallel between the S pole of the MOSFET QD1 and the primary discharge control loop, and the resistor R2 is further connected in series with a resistor R8 to be connected to the D pole of the MOS tube Q3 of the primary discharge control loop, a G pole of the MOS tube Q3 is connected to an AFE chip through a resistor R10, and a resistor R9 is connected in series between the G pole of the MOS tube Q3 and the S pole of the MOS tube Q3, and the S pole of the MOS tube Q3 is grounded.

[0041] About the charging control circuit of this solution: In some embodiments, the charging control loop includes a MOSFET QC1 arranged in a circuit between a sodium battery module and a negative terminal of a load loop, and a capacitor C1 and a capacitor C2 connected in series between an S pole and a D pole of the MOSFET QC1, wherein the G pole and the D pole of the MOSFET QC1 are connected to a primary charging control loop, the S pole of the MOSFET QC1 is connected to the S pole of the MOSFET QD1, and the D pole of the MOSFET QC1 is connected to the negative terminal of the load loop, wherein a voltage stabilizing diode ZD1 and a resistor R1 are connected in parallel between the D pole of the MOSFET QC1 and the primary charging control loop, and the resistor R1 is connected in series with a resistor R5 and then connected to the D pole of the MOS tube Q2 of the primary charging control loop, the G pole of the MOS tube Q2 is connected to the AFE chip through a resistor R7, and a resistor R6 is connected in parallel between the S pole of the MOS tube Q2 and the G pole of the MOS tube Q2, and the S pole of the MOS tube Q2 is grounded.

[0042] The same positive terminal / same negative terminal charge and discharge control circuit for multiple groups of sodium ion batteries provided in this solution can be applied to the sodium battery BMS of electric two-wheeled vehicles using multiple groups of sodium ion batteries. Compared with traditional lithium ion batteries, sodium ion batteries can effectively solve the problem of high-temperature thermal runaway of sodium ion batteries and improve low-temperature endurance. The current lithium battery platform voltage range of outdoor smart travel electric two-wheeled vehicles is between 32V and 96V, that is, the number of battery cells in series is between 10 and 30, and the sodium ion battery platform voltage is similar to that of lithium ion batteries. Therefore, a BMS protection board that supports 30 strings is also required to be compatible with conventional two-wheeled vehicle batteries to ensure the safe use of sodium ion batteries. The same positive terminal / same negative terminal charge and discharge control circuit for multiple groups of sodium ion batteries provided in this solution can be used on the BMS protection board to protect the normal operation of sodium ion batteries.

[0043] Those skilled in the art should understand that the technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A common positive terminal charge and discharge control circuit for multiple groups of sodium ion batteries, connected between the sodium battery modules of the multiple groups of sodium ion batteries and a load circuit, characterized in that: include: A current sampling circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load circuit; An analog front-end chip AFE connected to the sodium battery module and the current sampling circuit; A main charge and discharge circuit and a main control MCU are communicatively connected to the analog front-end chip AFE, wherein the main charge and discharge circuit includes a charge control circuit and a discharge control circuit connected in series between the positive terminal of the sodium battery module and the load circuit, wherein a MOSFET QC1 is arranged on the charge control circuit, a MOSFET QC2 is arranged on the discharge control circuit, a pre-discharge circuit is connected in parallel to the discharge control circuit, and a MOS tube Q5 and a positive temperature coefficient thermistor F2 are arranged on the pre-discharge circuit; A secondary protection circuit is communicatively connected to the sodium ion module and the main control MCU, wherein the secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium ion batteries of the sodium battery module, and a MOS tube Q1 connected to the output end of the secondary protection chip U1, a state feedback MOS tube Q4, and a one-time three-terminal fuse F1. The one-time three-terminal fuse F1 is controlled by the MOS tube Q1 at the output end to achieve melting.

2. The same positive terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 1, characterized in that: Capacitors C6 and C7 are connected in series between the positive electrode P+ / C+ and the negative electrode P- / C- of the load circuit; bidirectional transient voltage suppression diode TVS2 is connected in series between the positive electrode P+ / C+ and the negative electrode P- / C- of the load circuit; ordinary Schottky diode TVS1 is connected in series between the positive electrode P+ / C+ and the negative electrode P- / C- of the load circuit, and ordinary Schottky diode TVS1 is connected in reverse parallel to the load circuit.

3. The same positive terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 1, characterized in that: The charging control circuit includes a MOSFET QC1 arranged in a circuit between the positive terminal of the sodium battery module and the load circuit, and a capacitor C1 and a capacitor C2 connected in series between the S pole and the D pole of the MOSFET QC1, wherein the G pole and the D pole of the MOSFET QC1 are connected to the primary charging control circuit, the S pole of the MOSFET QC1 is connected to the No. 3 pin of the one-time three-terminal fuse F1, and the D pole is connected to the D pole of the MOSFET QD1, wherein a voltage stabilizing diode ZD1 and a resistor R1 are connected in parallel between the D pole of the MOSFET QC1 and the primary charging control circuit, and the resistor R1 is connected in series with a resistor R5 and then connected to the D pole of the MOS tube Q2 of the primary charging control circuit, the G pole of the MOS tube Q2 is connected to the AFE chip through a resistor R7, and a resistor R6 is connected in parallel between the S pole of the MOS tube Q2 and the G pole of the MOS tube Q2, and the S pole of the MOS tube Q2 is grounded.

4. The same positive terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 1, characterized in that: The discharge control loop includes a MOSFET QD1 arranged in a circuit between a sodium battery module and a positive electrode of a load loop, and a capacitor C3 and a capacitor C4 connected in series between a source electrode and a drain electrode of the MOSFET QD1, wherein a G electrode and an S electrode of the MOSFET QD1 are connected to a primary discharge control loop, a D electrode of the MOSFET QD1 is connected to a D electrode of a MOSFET QC1, an S electrode of the MOSFET QD1 is connected to a positive electrode of the load loop, an S electrode of the MOS tube Q3 is grounded, a voltage stabilizing diode ZD2 and a resistor R2 are connected in parallel between the S electrode of the MOSFET QD1 and the primary discharge control loop, and the resistor R2 is further connected in series with a resistor R8 to be connected to the D electrode of the MOS tube Q3 of the primary discharge control loop, a G electrode of the MOS tube Q3 is connected to an AFE chip through a resistor R10, a resistor R9 is connected in series between the G electrode of the MOS tube Q3 and the S electrode of the MOS tube Q3, and the S electrode of the MOS tube Q3 is grounded.

5. The same positive terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 1, characterized in that: The pre-discharge circuit includes a MOS tube Q5 and a positive temperature coefficient thermistor F2 connected in parallel to the discharge control circuit, wherein the D pole of the MOS tube Q5 is connected to the first pin of the positive temperature coefficient thermistor F2, the second pin of the positive temperature coefficient thermistor F2 is connected to the negative terminal of the load circuit, the S pole of the MOS tube Q5 is connected to the other end of the pre-discharge circuit, the S pole of the MOS tube Q5 is connected to the G pole of the MOS tube Q5 through a resistor R21 and a voltage stabilizing diode Z2, and the G pole of the MOS tube Q5 is connected to the collector of the triode Q6 through a resistor R23, the emitter of the triode Q6 is grounded, and the base of the triode Q6 is connected to the main control MCU through a resistor R20 for communication, and is grounded through a resistor R22.

6. The same positive terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 1, characterized in that: The output end of the secondary protection chip U1 on the secondary protection circuit is connected to the G pole of the state feedback MOS tube Q4 through the resistor R17, the S pole of the state feedback MOS tube Q4 is grounded, the D pole of the state feedback MOS tube Q4 feeds back the signal through R19 and is connected to the main control MCU for communication, the output end of the secondary protection chip U1 is connected to the G pole of the MOS tube Q1 through the resistor R3, the D pole of the MOS tube Q1 is connected to the No. 2 pin of the one-time three-terminal fuse F1, the S pole of the MOS tube Q1 is grounded, and the S pole and the D pole of the MOS tube Q1 are connected in parallel through the voltage regulator diode ZD1 and the capacitor C5 respectively, the No. 1 pin of the one-time three-terminal fuse F1 is connected to the positive pole of the sodium battery module, and the No. 3 pin is connected to the MOSFET QC1.

7. A charge and discharge control circuit for the negative terminal of multiple groups of sodium ion batteries, connected between the sodium battery modules of the multiple groups of sodium ion batteries and a load circuit, characterized in that: include: A current sampling circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load circuit; An analog front-end chip AFE connected to the sodium battery module and the current sampling circuit; A main charge and discharge circuit and a main control MCU are communicatively connected to the analog front-end chip AFE, wherein the main charge and discharge circuit includes a discharge control circuit and a charge control circuit connected in series between the negative terminal of the sodium battery module and the load circuit, wherein a MOSFET QC1 is provided on the charge control circuit, a MOSFET QC2 is provided on the discharge control circuit, a pre-discharge circuit is connected in parallel to the discharge control circuit, and a MOS tube Q5 and a positive temperature coefficient thermistor F2 are provided on the pre-discharge circuit; A secondary protection circuit is communicatively connected to the sodium ion module and the main control MCU, wherein the secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium ion batteries of the sodium battery module, and a MOS tube Q1 connected to the output end of the secondary protection chip U1, a state feedback MOS tube Q4, and a one-time three-terminal fuse F1. The one-time three-terminal fuse F1 is controlled by the MOS tube Q1 at the output end to achieve melting.

8. The same-port negative terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 7, characterized in that: The discharge control loop includes a MOSFET QD1 arranged on a circuit between a sodium battery module and a negative electrode of a load loop, and a capacitor C3 and a capacitor C4 connected in series between a source electrode and a drain electrode of the MOSFET QD1, wherein a G electrode and an S electrode of the MOSFET QD1 are connected to a primary discharge control loop, a D electrode of the MOSFET QD1 is connected to an output end of a current sampling circuit, an S electrode of the MOSFET QD1 is connected to a negative electrode connection terminal of the load loop, an S electrode of the MOS tube Q3 is grounded, a voltage stabilizing diode ZD2 and a resistor R2 are connected in parallel between the S electrode of the MOSFET QD1 and the primary discharge control loop, and the resistor R2 is further connected in series with a resistor R8 to be connected to the D electrode of the MOS tube Q3 of the primary discharge control loop, a G electrode of the MOS tube Q3 is connected to an AFE chip through a resistor R10, a resistor R9 is connected in series between the G electrode of the MOS tube Q3 and the S electrode of the MOS tube Q3, and the S electrode of the MOS tube Q3 is grounded.

9. The same negative terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 7, characterized in that: The charging control circuit includes a MOSFET QC1 arranged in a circuit between the negative terminal of the sodium battery module and the load circuit, and a capacitor C1 and a capacitor C2 connected in series between the S pole and the D pole of the MOSFET QC1, wherein the G pole and the D pole of the MOSFET QC1 are connected to the primary charging control circuit, the S pole of the MOSFET QC1 is connected to the S pole of the MOSFET QD1, and the D pole of the MOSFET QC1 is connected to the negative terminal of the load circuit, wherein a voltage stabilizing diode ZD1 and a resistor R1 are connected in parallel between the D pole of the MOSFET QC1 and the primary charging control circuit, and the resistor R1 is connected in series with a resistor R5 and then connected to the D pole of the MOS tube Q2 of the primary charging control circuit, the G pole of the MOS tube Q2 is connected to the AFE chip through a resistor R7, and a resistor R6 is connected in parallel between the S pole of the MOS tube Q2 and the G pole of the MOS tube Q2, and the S pole of the MOS tube Q2 is grounded.

10. The same-port negative terminal charge and discharge control circuit of multiple groups of sodium ion batteries according to claim 7, characterized in that: The output end of the secondary protection chip U1 on the secondary protection circuit is connected to the G pole of the state feedback MOS tube Q4 through the resistor R17, the S pole of the state feedback MOS tube Q4 is grounded, the D pole of the state feedback MOS tube Q4 feeds back the signal through R19 and is connected to the main control MCU for communication, the output end of the secondary protection chip U1 is connected to the G pole of the MOS tube Q1 through the resistor R3, the D pole of the MOS tube Q1 is connected to the No. 2 pin of the one-time three-terminal fuse F1, the S pole of the MOS tube Q1 is grounded, and the S pole and the D pole of the MOS tube Q1 are connected in parallel through the voltage regulator diode ZD1 and the capacitor C5 respectively, the No. 1 pin of the one-time three-terminal fuse F1 is connected to the positive pole of the sodium battery module, and the No. 3 pin is connected to the MOSFET QC1.

Images