A same-port positive terminal and negative terminal charge-discharge control circuit for multiple groups of sodium-ion batteries

Abstract

The scheme provides a same-port positive end and negative end charge-discharge control circuit of multiple groups of sodium ion batteries, comprising a main charge-discharge loop controlled by an AFE and a secondary protection circuit controlled by a main control MCU, the secondary protection circuit comprising a secondary protection chip U1 connected with multiple sodium ion batteries of the same sodium battery module, a MOS tube Q1 connected at an output end of the secondary protection chip U1, a state feedback MOS tube Q4, and a one-time fusing three-terminal fuse F1, the one-time fusing three-terminal fuse F1 being controlled to fuse by the MOS tube Q1, the secondary protection circuit being introduced to realize safety protection of the multiple groups of sodium ion batteries, the safety of battery use being strengthened, and the high-temperature thermal runaway problem of the sodium ion battery and the low-temperature endurance capability being effectively solved.

Description

Technical Field

[0001] This invention relates to the field of circuits, and in particular to a charging and discharging control circuit for the positive and negative terminals of multiple sodium-ion batteries. Background Technology

[0002] Most battery management systems on the market are designed for lithium-ion batteries. However, lithium-ion batteries require scarce lithium resources for their cathode materials, and they also pose inherent safety risks, especially during high-temperature driving and charging, where they carry a significant risk of thermal runaway. Furthermore, their discharge efficiency is low at temperatures below -20°C. In contrast, sodium-ion batteries have a higher internal resistance than lithium-ion batteries, making them less prone to thermal runaway at high temperatures. They also offer better low-temperature discharge performance and a wider discharge voltage platform, with a minimum discharge voltage as low as 2V. Therefore, they are more suitable for outdoor applications.

[0003] However, most battery management systems currently on the market are designed for series-connected lithium-ion batteries and cannot fully adapt to the management of sodium-ion batteries. Although there is some research on battery management for series-connected sodium-ion battery packs, such as the existing technology disclosed in CN221531029U, which discloses a protection board with five sodium-ion batteries in series, including a battery overcharge and over-discharge protection module, a battery temperature protection module, and a battery overcurrent protection module, this technology is a battery hardware protection solution. However, it suffers from inaccurate estimation of battery SOC current and only considers primary protection in terms of charging protection, without considering secondary charging protection in the event of protection chip failure, which poses a charging hazard. Another example is CN116979659B, which discloses a BMS protection board with 15 sodium-ion batteries in series. However, the simulated front-end chip only performs voltage acquisition and lacks equalization, temperature detection, and secondary charging protection functions. In the event of simulated front-end failure, the charging protection will fail, posing a hazard. Furthermore, this technology can only support 48V sodium battery packs and cannot be used for the protection of more sodium-ion battery packs. Summary of the Invention

[0004] The purpose of this invention is to provide a charging and discharging control circuit for the positive and negative terminals of multiple sodium-ion batteries. A secondary protection circuit is introduced to achieve safety protection for multiple sodium-ion batteries and enhance the safety of battery use.

[0005] To achieve the above objectives, this technical solution provides a common-port positive terminal charge / discharge control circuit for multiple sodium-ion batteries, connected between the sodium battery module and the load circuit, including:

[0006] 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.

[0007] The analog front-end chip AFE, which is 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 charge and discharge protection strategies.

[0008] The main charging and discharging circuit and the main control MCU are connected in communication with the analog front-end chip AFE. The main charging and discharging circuit includes a charging control circuit and a discharging control circuit connected in series between the positive terminal of the sodium battery module and the load circuit. The charging control circuit is equipped with MOSFET QC1 to control the conduction and cutoff of the charging path, and the discharging control circuit is equipped with MOSFET QC2 to control the conduction and cutoff of the discharging path. A pre-discharge circuit is connected in parallel with the discharging control circuit. The pre-discharge circuit is equipped with MOSFET Q5 and positive temperature coefficient thermistor F2 to absorb the instantaneous current of the sodium-ion battery module when it is turned on, so that the capacitor on the load circuit is pre-charged and the MOSFET QC2 of the main discharge circuit is broken down by the surge current.

[0009] The secondary protection circuit is 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, a MOS transistor Q1, a status feedback MOS transistor Q4, and a one-time blow three-terminal fuse F1 connected to the output terminal of the secondary protection chip U1. The one-time blow three-terminal fuse F1 is controlled by the MOS transistor Q1 at the output terminal to achieve melting.

[0010] On the other hand, this solution provides a common-port negative-terminal charge / discharge control circuit for multiple sodium-ion batteries, connected between the sodium battery module and the load circuit of the multiple sodium-ion batteries, including:

[0011] 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.

[0012] The analog front-end chip AFE, which is 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 charge and discharge protection strategies.

[0013] The main charging and discharging circuit and the main control MCU are connected in communication with the analog front-end chip AFE. The main charging and discharging circuit includes a discharge control circuit and a charging control circuit connected in series between the negative terminal of the sodium battery module and the load circuit. The charging control circuit is equipped with MOSFET QC1 to control the conduction and cutoff of the charging path, and the discharge control circuit is equipped with MOSFET QC2 to control the conduction and cutoff of the discharge path. A pre-discharge circuit is connected in parallel with the discharge control circuit. The pre-discharge circuit is equipped with MOSFET Q5 and positive temperature coefficient thermistor F2 to absorb the instantaneous current of the sodium-ion battery module when it is turned on.

[0014] The secondary protection circuit is 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, a MOS transistor Q1, a status feedback MOS transistor Q4, and a one-time blow three-terminal fuse F1 connected to the output terminal of the secondary protection chip U1. The one-time blow three-terminal fuse F1 is controlled by the MOS transistor Q1 at the output terminal to achieve melting.

[0015] Compared with existing technologies, this technical solution has the following characteristics and beneficial effects:

[0016] 1. This solution addresses the complex scenario of multiple sodium-ion batteries connected in series, employing a dual mechanism of AFE (Active Factor Exhaust) main protection and secondary protection. When the AFE chip fails to trigger overcharge protection due to a malfunction, the secondary protection circuit monitors the battery voltage in real time through the secondary protection chip U1. Once overvoltage occurs, it triggers a one-time blowout of the three-terminal fuse F1, completely cutting off the charging circuit. Compared to traditional single-stage protection solutions, this design avoids the risk of battery explosion due to AFE failure or charging MOSFET breakdown, making it particularly suitable for the stringent safety requirements of 10-30 series high-voltage sodium battery packs.

[0017] 2. To address common issues in parallel / series battery applications such as power-on surges, hot-plug spikes, and short-circuit impacts, the solution integrates triple protection: a pre-discharge circuit using a PTC thermistor F2 and MOSFET Q5 to limit current at power-on, protecting the main MOSFET from breakdown by surges of hundreds of amps; a TVS + capacitor combination using TVS2 at the load end to suppress static electricity, and C6 / C7 to absorb hot-plug voltage spikes; and a reverse freewheeling design where TVS1 guides residual charge to dissipate heat during short circuits, preventing energy backflow and circuit damage.

[0018] 3. Adopting a same-port charging and discharging architecture, the AFE chip collects various battery parameter data of multiple sodium-ion batteries in real time to accurately generate charging and discharging protection strategies. With the coordinated control of the main / pre-charge MOSFETs, it can achieve three-level dynamic protection against overcharge / over-discharge / overcurrent, automatically switch between the main charging circuit and the pre-charge circuit during charging, and synchronously manage the output of multiple battery groups during discharging. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the control circuit for the positive terminal of multiple sodium-ion batteries.

[0020] Figure 2 This is a schematic diagram of the control circuit for the negative terminal of multiple sodium-ion batteries.

[0021] Figure 3This is a circuit diagram of the charging control loop in the positive and negative terminal control circuit of the same port.

[0022] Figure 4 This is a circuit diagram of the discharge control loop in the control circuit for the positive and negative terminals of the same port.

[0023] Figure 5 This is a circuit diagram of the pre-discharge circuit in the control circuit for the positive and negative terminals of the same port.

[0024] Figure 6 This is a circuit diagram of the secondary protection circuit in the control circuit for the positive and negative terminals of the same port. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0026] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0027] Example 1

[0028] like Figure 1 As shown, this solution provides a common-port positive terminal charge / discharge control circuit for multiple sodium-ion batteries, connected between the sodium battery module and the load circuit, including:

[0029] 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.

[0030] The analog front-end chip AFE, which is 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 charge and discharge protection strategies.

[0031] The main charging and discharging circuit and the main control MCU are connected in communication with the analog front-end chip AFE. The main charging and discharging circuit includes a charging control circuit and a discharging control circuit connected in series between the positive terminal of the sodium battery module and the load circuit. The charging control circuit is equipped with MOSFET QC1 to control the conduction and cutoff of the charging path, and the discharging control circuit is equipped with MOSFET QC2 to control the conduction and cutoff of the discharging path. A pre-discharge circuit is connected in parallel with the discharging control circuit. The pre-discharge circuit is equipped with MOSFET Q5 and positive temperature coefficient thermistor F2 to absorb the instantaneous current of the sodium-ion battery module when it is turned on.

[0032] The secondary protection circuit is 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, a MOS transistor Q1, a status feedback MOS transistor Q4, and a one-time blow three-terminal fuse F1 connected to the output terminal of the secondary protection chip U1. The one-time blow three-terminal fuse F1 is controlled by the MOS transistor Q1 at the output terminal to achieve melting.

[0033] Regarding the positive terminal control circuit of the multiple sodium-ion batteries in this scheme, the main charging and discharging circuit is connected in series between the positive terminals of the sodium battery module and the load circuit. The state of the device is activated or controlled by applying an effective signal to the positive terminals of the sodium battery module and the load circuit.

[0034] The same-port positive terminal control circuit provided in this solution is specifically designed for battery protection of multiple sodium-ion batteries. It can trigger a secondary protection circuit to protect against overvoltage and other conditions in the event of a simulated front-end chip failure, thereby enhancing the safety of using multiple sodium-ion batteries.

[0035] In some embodiments, the main control MCU communicates with the analog front-end chip (AFE) via I2C without requiring communication isolation. The main control MCU sends a working command to the analog front-end chip (AFE) to control it to enter the working state; the analog front-end chip (AFE) sends feedback information to the main control MCU, including information such as individual cell voltage, maximum voltage, minimum voltage, maximum and minimum voltage difference, average voltage, total voltage, maximum adjacent cell voltage difference, maximum adjacent cell voltage difference channel number, internal temperature, current value, protection status, and equalization status.

[0036] Regarding the analog front-end chip (AFE) in the same-port positive terminal control circuit of the multiple sodium-ion batteries: After obtaining the working instructions from the main control MCU, the analog front-end chip (AFE) enters the working state. Subsequently, 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.

[0037] In some embodiments, the current sampling circuit includes resistors R24 and R25, a grounding resistor R26, and a current sampling resistor Rshunt1 connected to the AFE chip. The current sampling resistor Rshunt1 is connected in the circuit between the sodium battery module and the negative terminal of the load circuit. Resistor R24 ​​and grounding resistor R26 are connected at the same point in the circuit between the sodium battery module and the negative terminal of the load circuit, and this point is located on the side of the current sampling resistor Rshunt1 closer 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).

[0038] In some embodiments, the AFE collects battery parameter data of the sodium battery module, including battery SOC, SOH, total voltage, single cell voltage, charge / discharge current, battery pack temperature, charging MOS state, and discharging MOS state. It then analyzes the charge / discharge control signals corresponding to the battery parameter data and generates charge / discharge protection strategies, including at least one of the following: single cell overvoltage protection, single cell undervoltage protection, charge / discharge overcurrent protection, short circuit protection, overtemperature protection, low temperature charging protection, and charging timeout protection.

[0039] In some embodiments, the same-port positive terminal control circuit of the multiple sodium-ion batteries in this solution can also absorb voltage spikes during hot-swapping during charging and discharging. Specifically, in this solution, capacitors C6 and C7 are connected in series between the positive terminal P+ / C+ and the negative terminal P- / C- of the load circuit. Capacitors C6 and C7 can absorb the voltage spikes generated instantaneously by the load in the load circuit during hot-swapping.

[0040] In some embodiments, the same-port positive terminal control circuit of the multiple sodium-ion batteries in this solution can also realize electrostatic discharge protection during charging, discharging, and hot-swapping. Specifically, this solution connects a bidirectional transient voltage suppressor diode TVS2 in series between the positive terminal P+ / C+ and the negative terminal P- / C- of the load circuit to suppress static electricity absorption.

[0041] In some embodiments, the same-port positive terminal control circuit of the multiple sodium-ion batteries in this solution can also realize short-circuit freewheeling protection for the positive and negative terminals of the load circuit. Specifically, in this solution, a common Schottky diode TVS1 is connected in series between the positive terminal P+ / C+ and the negative terminal P- / C- of the load circuit, and the common Schottky diode TVS1 is connected in parallel with the load circuit in reverse. Correspondingly, the polarity of the load circuit is set to positive at the top and negative at the bottom when the load circuit is in normal operation. When a short circuit is formed between the positive and negative terminals of the load circuit, a large current is generated. The large current flows through the MOSFET QC1 set on the charging control circuit and the MOSFET QC2 set on the discharging control circuit, so that MOSFET QC1 and MOSFET QC2 are immediately turned off. At this time, the polarity of the load circuit changes to negative at the top and positive at the bottom, and the remaining charge is dissipated by heat in the load circuit through the freewheeling current of the common Schottky diode TVS1, so as to prevent the peak energy when the load circuit is short-circuited from entering the transient voltage suppression diode TVS2 or capacitor C6 or capacitor C7.

[0042] The structure of the charging control circuit in this scheme is as follows: Figure 3 As shown:

[0043] In some embodiments, the charging control circuit includes a MOSFET QC1 disposed in the circuit between the positive terminal of the sodium battery module and the load circuit, and capacitors C1 and C2 connected in series between the source (S) and drain (D) of the MOSFET QC1. The gate (G) and drain (D) of the MOSFET QC1 are connected to the primary charging control circuit. The source (S) of the MOSFET QC1 is connected to pin 3 of a one-time blown three-terminal fuse F1, and the drain (D) is connected to the drain (D) of the MOSFET QD1. A Zener diode ZD1 and a resistor R1 are connected in parallel between the drain (D) of the MOSFET QC1 and the primary charging control circuit. The resistor R1 is connected in series with a resistor R5 and then connected to the drain (D) of the MOSFET Q2 in the primary charging control circuit. The gate (G) of the MOSFET Q2 is connected to the AFE chip through a resistor R7. A resistor R6 is connected in parallel between the source (S) and gate (G) of the MOSFET Q2, and the source (S) of the MOSFET Q2 is grounded.

[0044] The structure of the discharge control circuit in this scheme is as follows: Figure 4 As shown:

[0045] In some embodiments, the discharge control circuit includes a MOSFET QD1 disposed in the circuit between the sodium battery module and the positive terminal of the load circuit, and capacitors C3 and C4 connected in series between the source and drain of MOSFET QD1. The gate and source of MOSFET QD1 are connected to the primary discharge control circuit, the drain of MOSFET QD1 is connected to the drain of MOSFET QC1, the source of MOSFET QD1 is connected to the positive terminal of the load circuit, the source of MOSFET Q3 is grounded, a Zener diode ZD2 and a resistor R2 are connected in parallel between the source of MOSFET QD1 and the primary discharge control circuit, and the resistor R2 is further connected in series with a resistor R8 to the drain of MOSFET Q3 in the primary discharge control circuit. The gate of MOSFET Q3 is connected to the AFE chip through a resistor R10, and a resistor R9 is connected in series between the gate and the source of MOSFET Q3. The source of MOSFET Q3 is grounded.

[0046] When the analog front-end chip (AFE) obtains battery parameter data and determines that the voltage of the current sodium-ion battery module triggers the first-level charging protection threshold, it triggers the charge and discharge protection strategy that responds to the single-cell overvoltage protection in response to overcharge protection. At this time, MOSFET QC1 is turned off while MOSFET QD1 remains on, charging is cut off, and the current of the sodium-ion battery pack is supplied to the load circuit through the body diode in MOSFET QC1. Furthermore, when the current sampling circuit detects that the current exceeds 300mA, MOSFET QC1 is turned on again to end the charging cut-off protection and reduce heat generation.

[0047] When the analog front-end chip (AFE) acquires battery parameter data and determines that the voltage of the current sodium-ion battery module has reached the over-discharge protection threshold, it triggers a charge / discharge protection strategy that responds to over-discharge protection and individual cell undervoltage protection. At this time, MOSFET QD1 is turned off while MOSFET QC1 remains on, disconnecting the main charge / discharge circuit to supply power to the load circuit. Simultaneously, an external charger connected between the positive and negative terminals of the load circuit charges the sodium-ion battery pack. Current flows through the body diode in MOSFET QD1 to the positive terminal of the sodium-ion battery pack. Furthermore, when the current sampling circuit detects a current exceeding 300mA, MOSFET QD1 is turned on to end the discharge cutoff protection and reduce heat generation. Further, when the analog front-end chip (AFE) acquires battery parameter data and determines that the current in the current-ion battery module exceeds the current protection threshold during charging / discharging, it triggers a charge / discharge protection strategy that responds to overcurrent protection. At this time, MOSFET QD1 and MOSFET QC1 are turned off, completely disconnecting the positive terminal of the sodium-ion battery pack from the downstream charger or load.

[0048] Regarding the pre-discharge circuit of this scheme, the structure is as follows: Figure 5As shown:

[0049] In some embodiments, the pre-discharge circuit includes a MOSFET Q5 and a positive temperature coefficient thermistor F2 connected in parallel with the discharge control circuit. The drain (D) of the MOSFET Q5 is connected to pin 1 of the positive temperature coefficient thermistor F2, and pin 2 of the positive temperature coefficient thermistor F2 is connected to the negative terminal of the load circuit. The source (S) of the MOSFET Q5 is connected to the other end of the pre-discharge circuit. The source of the MOSFET Q5 is connected to the gate (G) of the MOSFET Q5 through resistor R21 and Zener diode Z2. Meanwhile, the gate of the MOSFET Q5 is connected to the collector of transistor Q6 through resistor R23. The emitter of transistor Q6 is grounded, and the base of transistor Q6 is connected to the main control MCU through resistor R20 and grounded through resistor R22.

[0050] Because the input terminal of the load's electronic control is equipped with a large capacitor, the sodium-ion battery pack's BMS will experience a sudden current of several hundred amps flowing into the large capacitor at the moment of power-on. This will put the MOSFETs QD1 and QC1 in the main charging and discharging circuit at great risk and make them prone to breakdown. To avoid damage to the MOSFETs, when the sodium-ion battery pack's BMS is powered on, the main control MCU controls MOSFET Q5 to be turned on for a period of time. During this time, the instantaneous large current passing through MOSFET Q5 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 MOSFET QD1 and turn off MOSFET Q5. This can serve as a pre-charging function at power-on.

[0051] The structure of the secondary protection circuit in this solution is as follows: Figure 6 As shown:

[0052] The secondary protection circuit includes a secondary protection chip U1 connected to multiple sodium-ion batteries in the sodium battery module, and a MOSFET Q1, a status feedback MOSFET Q4, and a one-time blown three-terminal fuse F1 connected to the output of the secondary protection chip U1. Further, the output of the secondary protection chip U1 is connected to the gate (G) of the status feedback MOSFET Q4 via resistor R17. The source (S) of the status feedback MOSFET Q4 is grounded, and the drain (D) of the status feedback MOSFET Q4 is connected to the main control MCU via resistor R19 for feedback signal communication. The output of the secondary protection chip U1 is connected to the gate (G) of the MOSFET Q1 via resistor R3. The drain (D) of the MOSFET Q1 is connected to pin 2 of the one-time blown three-terminal fuse F1. The source (S) of the MOSFET Q1 is grounded, and the source and drain of the MOSFET Q1 are connected in parallel via a Zener diode ZD1 and a capacitor C5, respectively. Pin 1 of the one-time blown three-terminal fuse F1 is connected to the positive terminal of the sodium battery module, and pin 3 is connected to MOSFET QC1.

[0053] When the sodium-ion battery pack is in normal charging mode, the output of the secondary protection chip U1 is low by default. At this time, the drain and source of MOSFET Q1 are disconnected, and pins 1 and 3 of the corresponding one-time blown three-terminal fuse F1 are turned on, while pin 2 is left floating. The main control MCU sends a command to the analog front-end chip AFE to generate a charging signal to initiate the normal charging process. The analog front-end chip AFE controls the drain of MOSFET Q2 to conduct to ground, thereby turning on the gate of MOSFET QC1. The drain and source of MOSFET QC1 are also turned on, putting MOSFET QC1 in an open state. Simultaneously, the analog front-end chip AFE controls MOSFET Q3 to conduct, so that the gate of MOSFET QD1 is turned on through MOSFET Q3, turning MOSFET QD1 on. This allows the charging current to flow from the positive input of the load circuit through MOSFET QD1, MOSFET QC1, and the one-time blown 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 protection threshold, an overcharge protection signal is generated to turn off the MOSFETs. QC1 enables battery protection.

[0054] When the analog front-end chip (AFE) fails, the overcharge protection signal cannot be triggered after the sodium-ion battery pack is fully charged. MOSFET QC1 remains on, and the external load current continues to charge the sodium-ion battery pack. When the battery voltage continues to rise to trigger the secondary protection threshold, the output C0 of the secondary protection chip U1 outputs a high level, turning on MOSFET Q1 so that its drain (D) is connected to ground. The current from the positive terminal of the sodium-ion battery pack flows from pin 1 of the one-time blown three-terminal fuse F1 to GND, instantly heating up and blowing the fuse to protect the battery from continuous overcharging. At the same time, the secondary protection chip U1 controls MOSFET Q4 to conduct to ground, and the T0_MCU signal goes low to notify the main control MCU that the one-time blown three-terminal fuse has blown.

[0055] The solution provides a common-port positive terminal control circuit for multiple sodium-ion batteries, which can provide a MOS control BMS scheme for the positive and negative terminals of sodium-ion battery packs with 10 to 30 series sodium-ion batteries. Furthermore, the secondary protection circuit can compensate for the deficiencies when the AFE fails or the charging protection MOS breaks down.

[0056] Example 2

[0057] like Figure 2 As shown, this solution provides a common-port negative terminal control circuit for multiple sodium-ion batteries, connected between the sodium battery module and the load circuit, including:

[0058] 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.

[0059] The analog front-end chip AFE, which is 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 charge and discharge protection strategies.

[0060] The main charging and discharging circuit and the main control MCU are connected in communication with the analog front-end chip AFE. The main charging and discharging circuit includes a discharge control circuit and a charging control circuit connected in series between the negative terminal of the sodium battery module and the load circuit. The charging control circuit is equipped with MOSFET QC1 to control the conduction and cutoff of the charging path, and the discharge control circuit is equipped with MOSFET QC2 to control the conduction and cutoff of the discharge path. A pre-discharge circuit is connected in parallel with the discharge control circuit. The pre-discharge circuit is equipped with MOSFET Q5 and positive temperature coefficient thermistor F2 to absorb the instantaneous current of the sodium-ion battery module when it is turned on.

[0061] The secondary protection circuit is 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, a MOS transistor Q1, a status feedback MOS transistor Q4, and a one-time blow three-terminal fuse F1 connected to the output terminal of the secondary protection chip U1. The one-time blow three-terminal fuse F1 is controlled by the MOS transistor Q1 at the output terminal to achieve melting.

[0062] It should be noted that the control circuit for the negative terminal of the multiple sodium-ion batteries differs from the control circuit for the positive terminal of the multiple sodium-ion batteries in that the charging control circuit and the discharging control circuit on the main charging and discharging circuit are connected in series between the negative terminals of the sodium battery module and the load circuit. The state of the device is activated or controlled by applying a valid signal to the negative terminals of the sodium battery module and the load circuit. Therefore, the content similar to Embodiment 1 will not be repeated; only the differences will be explained below:

[0063] In some embodiments, an additional isolation circuit module is added to the part of the main control MCU that communicates with the external system to prevent the excessive voltage generated by the load from damaging the MCU communication pins when the negative terminal MOS is turned off.

[0064] Regarding the discharge control circuit of this scheme:

[0065] In some embodiments, the discharge control circuit includes a MOSFET QD1 disposed in the circuit between the sodium battery module and the negative terminal of the load circuit, and capacitors C3 and C4 connected in series between the source and drain of the MOSFET QD1. The gate and source of the MOSFET QD1 are connected to the primary discharge control circuit. The drain of the MOSFET QD1 is connected to the output terminal of the current sampling circuit. The source of the MOSFET QD1 is connected to the negative terminal of the load circuit. The source of the MOSFET Q3 is grounded. A Zener diode ZD2 and a resistor R2 are connected in parallel between the source of the MOSFET QD1 and the primary discharge control circuit. The resistor R2 is further connected in series with a resistor R8 to the drain of the MOSFET Q3 in the primary discharge control circuit. The gate of the MOSFET Q3 is connected to the AFE chip through a resistor R10. A resistor R9 is connected in series between the gate and the source of the MOSFET Q3. The source of the MOSFET Q3 is grounded.

[0066] Regarding the charging control circuit of this solution:

[0067] In some embodiments, the charging control circuit includes a MOSFET QC1 disposed in the circuit between the sodium battery module and the negative terminal of the load circuit, and capacitors C1 and C2 connected in series between the source (S) and drain (D) of MOSFET QC1. The gate (G) and drain (D) of MOSFET QC1 are connected to the primary charging control circuit, the source (S) of MOSFET QC1 is connected to the source (S) of MOSFET QD1, and the drain (D) of MOSFET QC1 is connected to the negative terminal of the load circuit. A Zener diode ZD1 and a resistor R1 are connected in parallel between the drain (D) of MOSFET QC1 and the primary charging control circuit. The resistor R1 is connected in series with a resistor R5 and then connected to the drain (D) of MOSFET Q2 in the primary charging control circuit. The gate (G) of MOSFET Q2 is connected to the AFE chip through a resistor R7. A resistor R6 is connected in parallel between the source (S) and gate (G) of MOSFET Q2, and the source (S) of MOSFET Q2 is grounded.

[0068] The multi-cell sodium-ion battery charging / discharging control circuit provided in this solution can be applied to the sodium battery BMS of electric two-wheelers using multiple sodium-ion batteries. Compared with traditional lithium-ion batteries, sodium-ion batteries can effectively solve the problem of high-temperature thermal runaway and improve low-temperature range. Currently, the lithium battery platform voltage range of outdoor smart electric two-wheelers is between 32V and 96V, that is, the number of cells connected in series is between 10 and 30. Since the sodium-ion battery platform voltage is similar to that of lithium-ion batteries, a BMS protection board that supports 30 cells is also needed to ensure compatibility with conventional two-wheeler batteries and ensure the safe use of sodium-ion batteries. The multi-cell sodium-ion battery charging / discharging control circuit provided in this solution can be used on the BMS protection board to protect the normal operation of sodium-ion batteries.

[0069] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been 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.

[0070] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A same-port positive terminal charging and discharging control circuit for multiple groups of sodium-ion batteries, connected between a sodium battery module and a load circuit of multiple groups of sodium-ion batteries, 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; The analog front-end chip AFE is connected to the sodium battery module and the current sampling circuit. The main charging and discharging circuit and the main control MCU are connected in communication with the analog front-end chip AFE. The main charging and discharging circuit includes a charging control circuit and a discharging control circuit connected in series between the positive terminal of the sodium battery module and the load circuit. The discharging control circuit is equipped with a MOSFET. QC2 is a pre-discharge circuit connected in parallel to the discharge control circuit. The pre-discharge circuit includes a MOSFET Q5 and a positive temperature coefficient (PTC) thermistor F2 connected in parallel to the discharge control circuit. The drain (D) of MOSFET Q5 is connected to pin 1 of the PTC thermistor F2, and pin 2 of the PTC thermistor F2 is connected to the negative terminal of the load circuit. The source (S) of MOSFET Q5 is connected to the other end of the pre-discharge circuit. The source of MOSFET Q5 is connected to the gate (G) of MOSFET Q5 through resistor R21 and Zener diode Z2. Simultaneously, the gate of MOSFET Q5 is connected to the collector of transistor Q6 through resistor R23. The emitter of transistor Q6 is grounded, and the base of transistor Q6 is connected to the main control MCU through resistor R20 and grounded through resistor R22. The charging control circuit includes a MOSFET QC1 located between the sodium battery module and the positive terminal of the load circuit, and capacitors C1 and C2 connected in series between the source (S) and drain (D) of MOSFET QC1. The gate (G) and drain (D) of MOSFET QC1 are connected to the primary charging control circuit. The source (S) of MOSFET QC1 is connected to pin 3 of the three-terminal fuse F1, and the drain (D) is connected to the drain of MOSFET QD1. A Zener diode ZD1 and a resistor R1 are connected in parallel between the drain of MOSFET QC1 and the primary charging control circuit. Resistor R1 is connected in series with resistor R5 and then connected to the drain of MOSFET Q2 in the primary charging control circuit. The gate (G) of MOSFET Q2 is connected to the AFE chip through resistor R7. A resistor R6 is connected in parallel between the source (S) and gate (G) of MOSFET Q2. The source (S) of MOSFET Q2 is grounded. The secondary protection circuit is 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, a MOS transistor Q1, a status feedback MOS transistor Q4, and a one-time fuse F1 connected to the output terminal of the secondary protection chip U1. The one-time fuse F1 is controlled by the MOS transistor Q1 at the output terminal to achieve melting. When the analog front-end chip AFE runs invalid, the overcharge protection signal cannot be triggered after the battery of the sodium-ion battery pack is fully charged, the MOSFET QC1 remains in the on state, the battery voltage continues to rise to trigger the secondary protection threshold, and the output end C0 of the secondary protection chip U1 outputs a high level to turn on the MOS tube Q1, and the current of the positive electrode of the sodium-ion battery pack flows from the No. 1 pin of the one-time fusing three-terminal fuse F1 to GND.

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

3. The same-port positive terminal charging and discharging control circuit of the multiple groups of sodium-ion batteries according to claim 1, characterized in that, The discharge control loop comprises a MOSFET QD1 arranged on a circuit between the sodium battery module and the positive pole of the load loop and a capacitor C3 and a capacitor C4 connected in series between the source and the drain of the MOSFET QD1, wherein the G pole and the S pole of the MOSFET QD1 are connected to the primary discharge control loop, the D pole of the MOSFET QD1 is connected to the D pole of the MOSFET QC1, the S pole of the MOSFET QD1 is connected to the positive pole of the load loop, the S pole of the MOS tube Q3 is connected to the ground, the S pole of the MOSFET QD1 and the primary discharge control loop are connected in parallel with the voltage stabilizing diode ZD2 and the resistor R2, the resistor R2 is further connected in series with the resistor R8 to be connected to the D pole of the MOS tube Q3 of the primary discharge control loop, the G pole of the MOS tube Q3 is connected in communication with the AFE chip through the resistor R10, the G pole of the MOS tube Q3 and the S pole of the MOS tube Q3 are connected in series with the resistor R9, and the S pole of the MOS tube Q3 is connected to the ground.

4. The same-port positive terminal charging and discharging control circuit of the 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 connected to the ground, the D pole of the state feedback MOS tube Q4 is connected in communication with the main control MCU through the R19 feedback signal, 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 fusing three-terminal fuse F1, the S pole of the MOS tube Q1 is connected to the ground, the S pole and the D pole of the MOS tube Q1 are connected in parallel through the voltage stabilizing diode ZD1 and the capacitor C5 respectively, the No. 1 pin of the one-time fusing 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.

5. A same-mouth negative terminal charging and discharging control circuit of a plurality of groups of sodium-ion batteries, connected between a sodium battery module and a load circuit of a plurality of groups of sodium-ion batteries, characterized in that, It comprises: a current sampling circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load loop; an analog front-end chip AFE connected with the sodium battery module and the current sampling circuit; and a secondary protection circuit connected in series between the positive terminal of the sodium battery module and the negative terminal of the load loop. The main charge-discharge circuit and the master control MCU are in communication connection with the analog front-end chip AFE. The main charge-discharge circuit comprises a discharge control circuit and a charge control circuit connected in series between the sodium battery module and the negative terminal of the load circuit. The MOSFET QC2 is arranged on the discharge control circuit. The pre-discharge circuit is connected in parallel on the discharge control circuit. The pre-discharge circuit comprises the MOS tube Q5 and the positive temperature coefficient thermistor F2 connected in parallel on the discharge control circuit. The D pole of the MOS tube Q5 is connected to the No. 1 pin of the positive temperature coefficient thermistor F2. The No. 2 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 resistance R21 and the voltage stabilizing diode Z2. The G pole of the MOS tube Q5 is connected to the collector of the triode Q6 through the resistance R23. The emitter of the triode Q6 is grounded. The base of the triode Q6 is in communication connection with the master control MCU through the resistance R20 and is grounded through the resistance R22. The secondary protection circuit is in communication connection with the sodium ion module and the master control MCU. The secondary protection circuit comprises the secondary protection chip U1 connected with the plurality of sodium ion batteries of the sodium battery module, the MOS tube Q1 connected at the output end of the secondary protection chip U1, the state feedback MOS tube Q4 and the one-time fuse three-terminal fuse F1. The one-time fuse three-terminal fuse F1 is controlled to be fused by the MOS tube Q1 at the output end. When the analog front-end chip AFE fails to operate, the overcharge protection signal cannot be triggered after the sodium ion battery pack is fully charged. When the MOSFET QC1 remains in the on state and the battery voltage continues to rise to trigger the secondary protection threshold, the output end CO of the secondary protection chip U1 outputs a high level, opens the MOS tube Q1, and the current of the positive terminal of the sodium ion battery pack flows from the No. 1 pin of the one-time fuse three-terminal fuse F1 to GND.

6. The same-mouth negative terminal charging and discharging control circuit of multiple groups of sodium-ion batteries according to claim 5, characterized in that, The discharge control circuit comprises a MOSFET QD1 arranged on a circuit between the sodium battery module and the negative pole of the load circuit, and a capacitor C3 and a capacitor C4 connected in series between the source and the drain of the MOSFET QD1, wherein the G pole and the S pole of the MOSFET QD1 are connected to the primary discharge control circuit, the D pole of the MOSFET QD1 is connected to the output end of the current sampling circuit, the S pole of the MOSFET QD1 is connected to the negative pole wiring end of the load circuit, the S pole of the MOS tube Q3 is grounded, the S pole of the MOSFET QD1 is connected in parallel between the primary discharge control circuit and the S pole of the MOS tube Q3, the S pole of the MOSFET QD1 is connected in series with the voltage stabilizing diode ZD2 and the resistor R2, and the resistor R2 is further connected in series with the resistor R8 to be connected to the D pole of the MOS tube Q3 of the primary discharge control circuit, the G pole of the MOS tube Q3 is connected in communication with the AFE chip through the resistor R10, the G pole of the MOS tube Q3 and the S pole of the MOS tube Q3 are connected in series with the resistor R9, and the S pole of the MOS tube Q3 is grounded.

7. The same-mouth negative terminal charging and discharging control circuit for multiple groups of sodium-ion batteries according to claim 5, 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 is connected in communication with the main control MCU through the R19 feedback signal, 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 fusing three-terminal fuse F1, the S pole of the MOS tube Q1 is grounded, the S pole and the D pole of the MOS tube Q1 are connected in parallel through the voltage stabilizing diode ZD1 and the capacitor C5 respectively, the No. 1 pin of the one-time fusing 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.

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