Control method of hybrid battery management circuit and hybrid battery management circuit

Abstract

The present application discloses a control method for a hybrid battery management circuit and a hybrid battery management circuit, relating to the field of battery management technology. The control method includes: during charging, if the total voltage of the lithium battery group is significantly higher, then the sodium battery group is charged; if the total voltage of the sodium battery group is significantly higher, then the lithium battery group is charged; if the total voltages of the two are close, then both are charged simultaneously, until the single cell voltage of any lithium battery reaches the full charge voltage and lasts for a first preset time, then the lithium battery group is controlled to stop charging first. During discharging, if the total voltage of the lithium battery group is significantly higher, then the lithium battery group is discharged; if the total voltage of the sodium battery group is significantly higher, then the sodium battery group is discharged; if the total voltages of the two are close, then both are discharged simultaneously, until the single cell voltage of any lithium battery reaches the empty voltage and lasts for a second preset time, then the lithium battery group is controlled to stop discharging first. The present application can improve the compatibility and safety of charging and discharging of different types of batteries.

Description

Technical Field

[0001] The present application relates to the technical field of battery management, and in particular to a control method for a hybrid battery management circuit and a hybrid battery management circuit. Background Art

[0002] With the growing global demand for clean energy and efficient energy storage systems, hybrid battery systems are gaining widespread attention as a solution that combines the advantages of multiple battery technologies. Connecting different types of batteries (such as lithium-ion batteries and sodium-ion batteries) in parallel has become an effective way to improve energy storage system performance. This configuration not only leverages the advantages of each battery type, such as the high energy density of lithium-ion batteries and the cost-effectiveness of sodium-ion batteries, but also achieves higher energy output, longer service life, and better environmental adaptability through optimized design.

[0003] However, due to the inherent differences in charging and discharging characteristics between lithium batteries and sodium batteries, existing hybrid battery management circuits lack effective charging and discharging management strategies, thereby reducing the performance of the overall battery system. Summary of the Invention

[0004] The main purpose of this application is to provide a control method for a hybrid battery management circuit, aiming to provide an effective hybrid battery management strategy and improve the charge and discharge performance of the hybrid battery management circuit.

[0005] To achieve the above objectives, the present application proposes a control method for a hybrid battery management circuit, wherein the hybrid battery management circuit includes a lithium battery pack and a sodium battery pack, wherein the lithium battery pack and the sodium battery pack are arranged in parallel. The control method includes:

[0006] Step S10, obtaining the first cell voltages of n lithium batteries and the second cell voltages of n sodium batteries, and determining the total voltage of the lithium battery pack and the total voltage of the sodium battery pack based on the n first cell voltages and the n second cell voltages;

[0007] Step S20: When the mixed charging condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, then control the sodium battery pack to be charged; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, then control the lithium battery to be charged; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, then control the lithium battery pack and the sodium battery pack to be charged simultaneously until the voltage of any one of the first cells reaches the full charge voltage of the lithium battery and lasts for a first preset time, then control the lithium battery pack to be stopped from being charged and control the sodium battery pack to be continued to be charged;

[0008] Step S30: When a mixed discharge condition is met, if the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is greater than a preset difference, the lithium battery group is controlled to be discharged; if the difference between the total voltage of the sodium battery group and the total voltage of the lithium battery group is greater than the preset difference, the sodium battery group is controlled to be discharged; if the absolute value of the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is not greater than the preset difference, the lithium battery group and the sodium battery group are controlled to be discharged simultaneously, until the voltage of any one of the first cells reaches the lithium battery empty voltage and lasts for a second preset time, then the lithium battery group is controlled to stop discharging, and the sodium battery group is controlled to continue discharging.

[0009] In one embodiment, before step S20, the control method further includes:

[0010] In response to a charge start instruction, obtaining an ambient temperature of an area where the lithium battery pack and the sodium battery pack are located;

[0011] If the ambient temperature is not within the safe charging temperature range of the lithium battery but is within the safe charging temperature range of the sodium battery, controlling the sodium battery pack to be charged;

[0012] If the ambient temperature is within the safe charging temperature range of the lithium battery and the safe charging temperature range of the sodium battery, it is determined that the mixed charging condition is met and step S20 is executed.

[0013] In one embodiment, before step S30, the control method further includes:

[0014] In response to a discharge start instruction, obtaining an ambient temperature of an area where the lithium battery pack and the sodium battery pack are located;

[0015] If the ambient temperature is not within the safe discharge temperature range of the lithium battery but is within the safe discharge temperature range of the sodium battery, controlling the sodium battery pack to discharge;

[0016] If the ambient temperature is within the safe discharge temperature range of the lithium battery and the safe discharge temperature range of the sodium battery, it is determined that the mixed discharge condition is met, and step S30 is executed.

[0017] In one embodiment, the hybrid battery management circuit further includes:

[0018] a first switch circuit, the first switch circuit being connected to the lithium battery pack, the first switch circuit being configured to connect the lithium battery pack when turned on, and disconnect the lithium battery pack when turned off;

[0019] a second switch circuit, the second switch circuit being connected to the first switch circuit and the sodium battery pack, respectively, the second switch circuit being configured to connect the sodium battery pack when turned on and disconnect the sodium battery pack when turned off;

[0020] a charge-discharge switch circuit, the charge-discharge switch circuit being connected to the first switch circuit and the second switch circuit respectively, the charge-discharge switch circuit being further configured to be connected to an external charging input terminal or a load, the charge-discharge switch circuit being configured to start charging and discharging the lithium battery and / or the sodium battery when turned on, and to stop charging and discharging the lithium battery and / or the sodium battery when turned off;

[0021] The step S20 specifically includes:

[0022] Step S21: When the mixed charging condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the first switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first switch circuit, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on, until the voltage of any one of the first cells reaches the full charge voltage of the lithium battery and lasts for the first preset time, at which time the first switch circuit is controlled to be turned off.

[0023] In one embodiment, step S30 specifically includes:

[0024] Step S31: When a mixed discharge condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the first switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first switch circuit, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on, until the voltage of any one of the first cells reaches the lithium battery empty voltage and lasts for the second preset time, at which time the first switch circuit is controlled to be turned off.

[0025] In one embodiment, the hybrid battery management circuit further includes:

[0026] a first temperature detection circuit, which is disposed near the lithium battery pack and is configured to detect a first ambient temperature of an area where the lithium battery pack is located and output a corresponding first temperature detection signal;

[0027] a second temperature detection circuit, the second temperature detection circuit being disposed close to the sodium battery pack and configured to detect a second ambient temperature of an area where the sodium battery pack is located and output a corresponding second temperature detection signal;

[0028] Before step S20, the control method further includes:

[0029] When the charge-discharge switch circuit is connected to the external charging input terminal, in response to the charge start instruction, obtaining the first temperature detection signal and the second temperature detection signal, and determining the first ambient temperature according to the first temperature detection signal, and determining the second ambient temperature according to the second temperature detection signal;

[0030] If the first ambient temperature is not within the safe charging temperature range of the lithium battery, and the second ambient temperature is within the safe charging temperature range of the sodium battery, controlling the second switch circuit to be connected to the charge and discharge switch circuit;

[0031] If the first ambient temperature is within the safe charging temperature range of the lithium battery and the second ambient temperature is within the safe charging temperature range of the sodium battery, it is determined that the mixed charging condition is met and step S21 is executed.

[0032] In one embodiment, before step S30, the control method further includes:

[0033] When the charge-discharge switch circuit is connected to a load, in response to a discharge start instruction, obtaining the first temperature detection signal and the second temperature detection signal, and determining the first ambient temperature according to the first temperature detection signal, and determining the second ambient temperature according to the second temperature detection signal;

[0034] If the first ambient temperature is not within the safe discharge temperature range of the lithium battery, and the second ambient temperature is within the safe discharge temperature range of the sodium battery, controlling the second switch circuit to be connected to the charge and discharge switch circuit;

[0035] If the first ambient temperature is within the safe discharge temperature range of the lithium battery and the second ambient temperature is within the safe discharge temperature range of the sodium battery, it is determined that the mixed discharge condition is met and step S31 is executed.

[0036] In one embodiment, the hybrid battery management circuit further includes:

[0037] a first current limiting switch circuit, the first current limiting switch circuit being connected to the lithium battery pack and the charge and discharge switch circuit, respectively, the first current limiting switch circuit being configured to connect to the lithium battery pack when turned on and limit the discharge current of the lithium battery pack, and to disconnect the lithium battery pack when turned off;

[0038] a second current limiting switch circuit, the second current limiting switch circuit being connected to the sodium battery pack and the charge and discharge switch circuit, respectively, the second current limiting switch circuit being configured to connect to the sodium battery pack when turned on and limit the discharge current of the sodium battery pack, and to disconnect the sodium battery pack when turned off;

[0039] The step S31 includes:

[0040] When the mixed discharge condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the first current limiting switch circuit and the charge-discharge switch circuit are controlled to be turned on, and after a third preset time, the first current limiting switch circuit is turned off and the first switch circuit is turned on. If the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the second current limiting switch circuit and the charge-discharge switch circuit are controlled to be turned on, and after the third preset time, the second current limiting switch circuit is turned off and the second switch circuit is turned on. If the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first current limiting switch circuit, the second current limiting switch circuit, and the charge-discharge switch circuit are controlled to be turned on, and after the third preset time, the first current limiting switch circuit and the second current limiting switch circuit are turned off, and the first switch circuit and the second switch circuit are turned on. This process continues until the voltage of any one of the first cells reaches the lithium battery discharge voltage and lasts for the second preset time, at which point the first switch circuit is controlled to be turned off.

[0041] In one embodiment, the hybrid battery management circuit further includes:

[0042] Voltage detection control signal input terminal;

[0043] a NOT gate circuit, wherein an input terminal of the NOT gate circuit is connected to the voltage detection control signal input terminal;

[0044] a first gating switch circuit, the first gating switch circuit being connected to n of the lithium batteries, the controlled end of the first gating switch circuit being connected to the output end of the NOT gate circuit, the first gating switch circuit being configured to connect the n lithium batteries when turned on to output a lithium battery voltage detection signal, and to disconnect the n lithium batteries when turned off to stop outputting the lithium battery voltage detection signal; wherein the lithium battery voltage detection signal is configured to indicate the voltages of the n first cells;

[0045] a second gate switch circuit, the second gate switch circuit being connected to the n sodium batteries, the controlled terminal of the second gate switch circuit being connected to the voltage detection control signal input terminal, the second gate switch circuit being configured to connect the n sodium batteries to output a sodium battery voltage detection signal when turned on, and disconnect the n sodium batteries to stop outputting the sodium battery voltage detection signal when turned off; wherein the sodium battery voltage detection signal is configured to indicate the voltages of the n second cells;

[0046] The step S10 specifically includes:

[0047] Outputting a first control signal to the voltage detection control signal input terminal to control the second selection switch circuit to be turned on, obtaining the sodium battery voltage detection signal, and calculating the total voltage of the sodium battery group;

[0048] Output a second control signal that is in phase with the first control signal to the voltage detection control signal input terminal to control the first selection switch circuit to be turned on, obtain the lithium battery voltage detection signal, and calculate the total voltage of the lithium battery pack.

[0049] The present application also proposes a hybrid battery management circuit, which applies the control method of the hybrid battery management circuit as described above.

[0050] The technical solution of the present application adopts a control method for a hybrid battery management circuit, the control method comprising: step S10, obtaining first cell voltages of n lithium batteries and second cell voltages of n sodium batteries, and determining the total voltage of the lithium battery pack and the total voltage of the sodium battery pack based on the n first cell voltages and the n second cell voltages. Step S20, when a hybrid charging condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, controlling the sodium battery pack to be charged; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, controlling the lithium battery to be charged; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, controlling the lithium battery pack and the sodium battery pack to be charged simultaneously, until any first cell voltage reaches the full charge voltage of the lithium battery and lasts for a first preset time, controlling the lithium battery pack to stop charging and controlling the sodium battery pack to continue charging. In step S30, when the mixed discharge condition is met, if the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is greater than a preset difference, the lithium battery group is controlled to be discharged; if the difference between the total voltage of the sodium battery group and the total voltage of the lithium battery group is greater than the preset difference, the sodium battery group is controlled to be discharged; if the absolute value of the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is not greater than the preset difference, the lithium battery group and the sodium battery group are controlled to be discharged simultaneously until any first cell voltage reaches the lithium battery empty voltage and lasts for a second preset time, at which time the lithium battery group is controlled to stop discharging and the sodium battery group is controlled to continue discharging. In this way, the present application can balance the voltage between the lithium battery group and the sodium battery group and ensure that both types of batteries are in a safe operating state throughout the entire charge and discharge cycle, thereby improving the compatibility and safety of the hybrid battery management circuit during charge and discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0052] Figure 1 This is a schematic flow chart of an embodiment of a control method for a hybrid battery management circuit provided by the present application;

[0053] Figure 2 A schematic structural diagram of an embodiment of a hybrid battery management circuit provided by this application;

[0054] Figure 3 This is an electronic circuit diagram of an embodiment of the hybrid battery management circuit provided by this application.

[0055] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0057] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0058] In addition, the descriptions of "first", "second", etc. in this application are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0059] It should be noted that due to the inherent differences in charging and discharging characteristics between lithium and sodium batteries, existing hybrid battery management circuits lack effective charge and discharge management strategies, thereby reducing the performance of the overall battery system. Specifically, the safe charging temperature range for lithium batteries is 0°C to 45°C, and the safe discharging temperature range for lithium batteries is -10°C to 50°C. The safe charging temperature range for sodium batteries is -20°C to 70°C, and the safe discharging temperature range for sodium batteries is -30°C to 70°C. The full charge voltage of a single lithium battery is 3.7V, and the full charge voltage of a single sodium battery is 4.0V. The discharge voltage of a single lithium battery is 2.5V, and the discharge voltage of a single sodium battery is 2.2V.

[0060] The present application proposes a control method for a hybrid battery management circuit.

[0061] See also Figure 1In one embodiment of the present application, the hybrid battery management circuit includes a lithium battery group and a sodium battery group, the lithium battery group includes n lithium batteries, the sodium battery group includes n sodium batteries, the lithium battery group and the sodium battery group are arranged in parallel, and the control method of the hybrid battery management circuit includes steps S10 to S30:

[0062] Step S10, obtaining first cell voltages of n lithium batteries and second cell voltages of n sodium batteries, and determining the total voltage of the lithium battery pack and the total voltage of the sodium battery pack based on the n first cell voltages and the n second cell voltages;

[0063] Step S20: When the mixed charging condition is met, if the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is greater than a preset difference, then control the sodium battery group to be charged; if the difference between the total voltage of the sodium battery group and the total voltage of the lithium battery group is greater than the preset difference, then control the lithium battery to be charged; if the absolute value of the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is not greater than the preset difference, then control the lithium battery group and the sodium battery group to be charged simultaneously until any first cell voltage reaches the full charge voltage of the lithium battery and continues for a first preset time, then control the lithium battery group to be stopped from charging and control the sodium battery group to continue charging;

[0064] Step S30: When the mixed discharge condition is met, if the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is greater than a preset difference, the lithium battery group is controlled to be discharged; if the difference between the total voltage of the sodium battery group and the total voltage of the lithium battery group is greater than the preset difference, the sodium battery group is controlled to be discharged; if the absolute value of the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is not greater than the preset difference, the lithium battery group and the sodium battery group are controlled to be discharged simultaneously until the voltage of any one of the first cells reaches the lithium battery empty voltage and lasts for a second preset time, at which time the lithium battery group is controlled to stop discharging and the sodium battery group is controlled to continue discharging.

[0065] It should be noted that n is a positive integer greater than or equal to 1. The total voltage of a lithium battery pack is the total voltage obtained by superimposing the voltages of n first cells, and the total voltage of a sodium battery pack is the total voltage obtained by superimposing the voltages of n second cells. Hybrid charging conditions may include conditions such as the ambient temperature range, battery health status, or power supply stability, while hybrid discharging conditions may include conditions such as the ambient temperature range, battery health status, or load demand, and are not limited here. For example, when the ambient temperature is between 0°C and 45°C, which is within the common safe charging temperature range for lithium and sodium batteries, both types of batteries are considered to meet the hybrid charging conditions, and step S20 can be executed. When the ambient temperature is between -10°C and 50°C, which is within the common safe discharging temperature range for lithium and sodium batteries, both types of batteries are considered to meet the hybrid discharging conditions, and step S30 can be executed.

[0066] In this embodiment, when mixed charging conditions are met, if the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is greater than a preset difference, it indicates that the total voltage of the lithium battery group is significantly higher than the total voltage of the sodium battery group. To balance the voltages between the lithium battery group and the sodium battery group during charging, the sodium battery group is controlled to be charged first. If the difference between the total voltage of the sodium battery group and the total voltage of the lithium battery group is greater than a preset difference, it indicates that the total voltage of the sodium battery group is significantly higher than the total voltage of the lithium battery group. To balance the voltages between the lithium battery group and the sodium battery group during charging, the lithium battery group is controlled to be charged first. If the absolute value of the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is not greater than the preset difference, it indicates that the total voltage of the lithium battery group and the total voltage of the sodium battery are relatively close, and the lithium battery group and the sodium battery group are in a voltage equilibrium state, and then the lithium battery group and the sodium battery group are controlled to be charged simultaneously. It is understandable that, since the full charge voltage of a single lithium battery is 3.7V, the full charge voltage of a single sodium battery is 4.0V, and the number of cells in both the lithium battery pack and the sodium battery pack is n, during the simultaneous charging of the lithium battery pack and the sodium battery pack, the lithium battery pack is fully charged before the sodium battery pack. When the voltage of any first cell reaches the full charge voltage of the lithium battery and persists for a first preset time, for example, 3.7V for 2 seconds, the lithium battery pack is considered fully charged. At this point, charging of the lithium battery pack is controlled to stop to prevent overcharging, while charging of the sodium battery pack continues. Similarly, when the voltage of any second cell reaches the full charge voltage of the sodium battery and persists for a first preset time, for example, 4.0V for 2 seconds, the sodium battery pack is considered fully charged and charging of the sodium battery pack is controlled to stop. Therefore, in one feasible embodiment, after the step of controlling the lithium battery pack to stop charging and the sodium battery pack to continue charging until the voltage of any first cell reaches the full charge voltage of the lithium battery and lasts for the first preset time, the control method may further include controlling the sodium battery pack to stop charging when the voltage of any second cell reaches the full charge voltage of the lithium battery and lasts for the first preset time.

[0067] In this embodiment, when mixed discharge conditions are met, if the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is greater than a preset difference, it indicates that the total voltage of the lithium battery group is significantly higher than the total voltage of the sodium battery group. To balance the voltages between the lithium battery group and the sodium battery group during discharge, the lithium battery group is controlled to be discharged first. If the difference between the total voltage of the sodium battery group and the total voltage of the lithium battery group is greater than a preset difference, it indicates that the total voltage of the sodium battery group is significantly higher than the total voltage of the lithium battery group. To balance the voltages between the lithium battery group and the sodium battery group during discharge, the sodium battery group is controlled to be discharged first. If the absolute value of the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is not greater than the preset difference, it indicates that the total voltage of the lithium battery group and the total voltage of the sodium battery are relatively close, and the lithium battery group and the sodium battery group are in a voltage equilibrium state, and the lithium battery group and the sodium battery group are controlled to be discharged simultaneously. It is understood that since the full charge voltage of a single lithium battery is 2.5V, the full charge voltage of a single sodium battery is 2.2V, and the number of cells in both the lithium battery pack and the sodium battery pack is n, during the simultaneous discharge of the lithium battery pack and the sodium battery pack, the lithium battery pack reaches a fully discharged state before the sodium battery pack. When the voltage of any first cell reaches the lithium battery empty voltage and persists for a first preset time, for example, 2.5V for 2 seconds, the lithium battery pack is considered fully discharged. At this point, discharge of the lithium battery pack is controlled to stop to prevent over-discharge, while discharge of the sodium battery pack continues. Similarly, when the voltage of any second cell reaches the sodium battery empty voltage and persists for a first preset time, for example, 2.5V for 2 seconds, the sodium battery pack is considered fully discharged, and discharge of the sodium battery pack is controlled to stop. Therefore, in another feasible embodiment, after the steps of controlling the lithium battery pack to stop discharging until the voltage of any first cell reaches the empty voltage of the lithium battery and lasts for a second preset time, and controlling the sodium battery pack to continue discharging, the control method further includes controlling the sodium battery pack to stop discharging when the voltage of any second cell reaches the empty voltage of the sodium battery and lasts for a second preset time.

[0068] In this way, the control method of this embodiment can be compatible with the differences in charging and discharging characteristics between lithium batteries and sodium batteries. Compared with the existing technology, the control method of this embodiment can balance the voltage between the lithium battery pack and the sodium battery pack and ensure that they are in a safe working state throughout the entire charge and discharge cycle, which can improve the compatibility and safety of the hybrid battery management circuit during charging and discharging.

[0069] In the present application, a control method for a hybrid battery management circuit includes: step S10, obtaining first cell voltages of n lithium batteries and second cell voltages of n sodium batteries, and determining a total voltage of a lithium battery pack and a total voltage of a sodium battery pack based on the n first cell voltages and the n second cell voltages. Step S20, when a hybrid charging condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, controlling charging of the sodium battery pack; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, controlling charging of the lithium battery; and if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, controlling simultaneous charging of the lithium battery pack and the sodium battery pack until any one of the first cell voltages reaches the full charge voltage of the lithium battery and lasts for a first preset time, controlling charging of the lithium battery pack to stop and controlling charging of the sodium battery pack to continue. In step S30, when the mixed discharge condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the lithium battery pack is controlled to be discharged; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the sodium battery pack is controlled to be discharged; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the lithium battery pack and the sodium battery pack are controlled to be discharged simultaneously until the voltage of any of the first cells reaches the lithium battery empty voltage and lasts for a second preset time, at which time the lithium battery pack is controlled to stop discharging and the sodium battery pack is controlled to continue discharging. In this way, the present application can balance the voltages between the lithium battery pack and the sodium battery pack, ensure that both types of batteries are in a safe operating state throughout the entire charge and discharge cycle, and improve the compatibility and safety of the hybrid battery management circuit during charge and discharge.

[0070] In one embodiment of the present application, before step S20, the control method further includes steps S01 to S03:

[0071] Step S01, in response to a charge start instruction, obtaining the ambient temperature of the area where the lithium battery pack and the sodium battery pack are located;

[0072] Step S02: If the ambient temperature is not within the safe charging temperature range of the lithium battery but is within the safe charging temperature range of the sodium battery, then control the sodium battery pack to be charged;

[0073] Step S03: If the ambient temperature is within the safe charging temperature range of the lithium battery and the safe charging temperature range of the sodium battery, it is determined that the mixed charging condition is met, and step S20 is executed.

[0074] Before step S30, the control method further includes steps S04 to S06:

[0075] Step S04, in response to the discharge start instruction, obtaining the ambient temperature of the area where the lithium battery pack and the sodium battery pack are located;

[0076] Step S05: If the ambient temperature is not within the safe discharge temperature range of the lithium battery but is within the safe discharge temperature range of the sodium battery, then control the sodium battery pack to discharge;

[0077] Step S06: If the ambient temperature is within the safe discharge temperature range of the lithium battery and the safe discharge temperature range of the sodium battery, it is determined that the mixed discharge condition is met, and step S30 is executed.

[0078] In this embodiment, the ambient temperature of the area where the lithium battery pack and the sodium battery pack are located is obtained. During charging, if the ambient temperature is not between -20°C (inclusive) and 0°C (excluding 0°C) or between 45°C (excluding 45°C) and 70°C (inclusive), the ambient temperature is not within the safe charging temperature range of 0°C to 45°C for lithium batteries, but is within the safe charging temperature range of -20°C to 70°C for sodium batteries, so charging of the sodium battery pack is controlled. If the ambient temperature is between 0°C and 45°C, the ambient temperature is within both the safe charging temperature range of 0°C to 45°C for lithium batteries and the safe charging temperature range of -20°C to 70°C for sodium batteries, so it is considered that the ambient temperature meets the mixed charging conditions, and the charging process executes steps S10 and S20, ensuring the safety of the charging process.

[0079] During discharge, if the ambient temperature is not within the safe discharge temperature range of -30°C (inclusive) to -10°C (excluding -10°C) or 50°C (excluding 50°C) to 70°C (inclusive), the ambient temperature is not within the safe discharge temperature range of -10°C to 50°C for lithium batteries, but is within the safe charging temperature range of -30°C to 70°C for sodium batteries, so the sodium battery pack is controlled to discharge. If the ambient temperature is between -10°C and 50°C, the ambient temperature is within both the safe charging temperature range of -10°C to 50°C for lithium batteries and the safe charging temperature range of -30°C to 70°C for sodium batteries, so it is considered that the ambient temperature meets the mixed discharge condition, and the charging step executes steps S10 and S30, ensuring the safety of the discharge process.

[0080] See also Figure 2 In one embodiment of the present application, the hybrid battery management circuit further includes:

[0081] a first switch circuit, the first switch circuit being connected to the lithium battery pack, and the first switch circuit being used to connect the lithium battery pack when turned on and disconnect the lithium battery pack when turned off;

[0082] a second switch circuit, the second switch circuit being connected to the first switch circuit and the sodium battery pack, respectively, and the second switch circuit being configured to connect the sodium battery pack when turned on and disconnect the sodium battery pack when turned off;

[0083] A charge and discharge switch circuit, the charge and discharge switch circuit being connected to the first switch circuit and the second switch circuit respectively, and the charge and discharge switch circuit being further configured to be connected to an external charging input terminal or a load, and the charge and discharge switch circuit being configured to start charging and discharging the lithium battery and / or the sodium battery when turned on, and to stop charging and discharging the lithium battery and / or the sodium battery when turned off;

[0084] Step S20 specifically includes:

[0085] Step S21: When the mixed charging condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than the preset difference, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the first switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first switch circuit, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on, until the voltage of any one of the first cells reaches the full charge voltage of the lithium battery and lasts for a first preset time, at which time the first switch circuit is controlled to be turned off.

[0086] Step S30 specifically includes:

[0087] Step S31: When the mixed discharge condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the first switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first switch circuit, the second switch circuit, and the charge-discharge switch circuit are controlled to be turned on, until the voltage of any one of the first cells reaches the lithium battery empty voltage and lasts for a second preset time, at which time the first switch circuit is controlled to be turned off.

[0088] In this embodiment, the charge and discharge process of the lithium battery pack can be independently controlled by the first switch circuit and the charge and discharge switch circuit, and the charge and discharge process of the sodium battery pack can be independently controlled by the second switch circuit and the charge and discharge switch circuit, so that the charge and discharge behavior of the hybrid battery management circuit can be accurately adjusted.

[0089] In one feasible embodiment, after the step of controlling the first switch circuit to turn off until the voltage of any one of the first cells reaches the full charge voltage of the lithium battery and lasts for a first preset time, the control method further includes: controlling the second switch circuit and the charge and discharge switch circuit to turn off until the voltage of any one of the second cells reaches the full charge voltage of the sodium battery and lasts for the first preset time.

[0090] In another feasible embodiment, after the step of controlling the first switch circuit to turn off until the voltage of any one of the first cells reaches the empty voltage of the lithium battery and lasts for a second preset time, the control method further includes: controlling the second switch circuit and the charge-discharge switch circuit to turn off until the voltage of any one of the second cells reaches the empty voltage of the sodium battery and lasts for a second preset time.

[0091] See also Figure 2 In one embodiment of the present application, the hybrid battery management circuit further includes:

[0092] a first temperature detection circuit, which is disposed close to the lithium battery pack and is used to detect a first ambient temperature of an area where the lithium battery pack is located and output a corresponding first temperature detection signal;

[0093] a second temperature detection circuit, which is disposed near the sodium battery pack and is used to detect a second ambient temperature of the area where the sodium battery pack is located and output a corresponding second temperature detection signal;

[0094] Before step S20, the control method further includes steps S011 to S031:

[0095] Step S011, when the charge-discharge switch circuit is connected to the external charging input terminal, in response to a charge start instruction, obtaining a first temperature detection signal and a second temperature detection signal, and determining a first ambient temperature according to the first temperature detection signal, and determining a second ambient temperature according to the second temperature detection signal;

[0096] Step S021: If the first ambient temperature is not within the safe charging temperature range of the lithium battery and the second ambient temperature is within the safe charging temperature range of the sodium battery, controlling the second switch circuit and the charge-discharge switch circuit to be conductive;

[0097] Step S031: If the first ambient temperature is within the safe charging temperature range of the lithium battery and the second ambient temperature is within the safe charging temperature range of the sodium battery, it is determined that the hybrid charging condition is met and step S21 is executed.

[0098] Before step S30, the control method further includes steps S041 to S061:

[0099] Step S041, when the charge-discharge switch circuit is connected to a load, in response to a discharge start instruction, obtaining a first temperature detection signal and a second temperature detection signal, and determining a first ambient temperature according to the first temperature detection signal, and determining a second ambient temperature according to the second temperature detection signal;

[0100] Step S051, if the first ambient temperature is not within the safe discharge temperature range of the lithium battery and the second ambient temperature is within the safe discharge temperature range of the sodium battery, controlling the second switch circuit and the charge and discharge switch circuit to be conductive;

[0101] Step S061: If the first ambient temperature is within the safe discharge temperature range of the lithium battery and the second ambient temperature is within the safe discharge temperature range of the sodium battery, it is determined that the mixed discharge condition is met, and step S31 is executed.

[0102] In this embodiment, a first temperature detection circuit is provided to detect the ambient temperature of the lithium battery pack, and a second temperature detection circuit is provided to detect the ambient temperature of the sodium battery pack, so that the obtained temperature detection results are more accurate.

[0103] See also Figure 2 In one embodiment of the present application, the hybrid battery management circuit further includes:

[0104] a first current limiting switch circuit, the first current limiting switch circuit being connected to the lithium battery pack and the charge and discharge switch circuit, respectively; the first current limiting switch circuit being used to connect to the lithium battery pack when turned on and limit the discharge current of the lithium battery pack, and to disconnect the lithium battery pack when turned off;

[0105] a second current limiting switch circuit, the second current limiting switch circuit being connected to the sodium battery pack and the charge and discharge switch circuit, respectively. The second current limiting switch circuit is configured to connect to the sodium battery pack when turned on and limit the discharge current of the sodium battery pack, and disconnect the sodium battery pack when turned off;

[0106] Step S31 includes step S311:

[0107] Step S311: When the mixed discharge condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the first current limiting switch circuit and the charge-discharge switch circuit are controlled to be turned on, and after a third preset time, the first current limiting switch circuit is turned off, and the first switch circuit is turned on. If the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the second current limiting switch circuit and the charge-discharge switch circuit are controlled to be turned on, and after the third preset time, the second current limiting switch circuit is turned off, and the second switch circuit is turned on. If the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first current limiting switch circuit, the second current limiting switch circuit, and the charge-discharge switch circuit are controlled to be turned on, and after the third preset time, the first current limiting switch circuit and the second current limiting switch circuit are turned off, and the first switch circuit and the second switch circuit are turned on. When the voltage of any one of the first cells reaches the lithium battery discharge voltage and lasts for a second preset time, the first switch circuit is controlled to be turned off.

[0108] It should be noted that during the initial discharge of a battery, due to its low internal impedance, large transient currents are easily generated, which can damage circuits or trigger circuit protection mechanisms, compromising the safe discharge process. In this embodiment, a first current-limiting switch circuit is provided in parallel with the first switch circuit. During the initial discharge of a lithium battery, the initial current is limited by the first current-limiting switch circuit, thereby improving the safety of lithium battery discharge. A second current-limiting switch circuit is provided in parallel with the second switch circuit. During the initial discharge of a sodium battery, the initial current is limited by the second current-limiting switch circuit, thereby improving the safety of sodium battery discharge.

[0109] See also Figure 2 In one embodiment of the present application, the hybrid battery management circuit further includes:

[0110] Voltage detection control signal input terminal;

[0111] A NOT gate circuit, wherein an input terminal of the NOT gate circuit is connected to an input terminal of a voltage detection control signal;

[0112] a first selection switch circuit, the first selection switch circuit being connected to n lithium batteries, the controlled end of the first selection switch circuit being connected to the output end of the NOT gate circuit, the first selection switch circuit being configured to connect the n lithium batteries when conducting to output a lithium battery voltage detection signal, and to disconnect the n lithium batteries when shutting down to stop outputting the lithium battery voltage detection signal; wherein the lithium battery voltage detection signal is configured to indicate the voltages of the n first cells;

[0113] a second gate switch circuit, the second gate switch circuit being connected to n sodium batteries, the controlled end of the second gate switch circuit being connected to the voltage detection control signal input end, the second gate switch circuit being configured to connect the n sodium batteries when conducting to output a sodium battery voltage detection signal, and to disconnect the n sodium batteries when conducting to stop outputting the sodium battery voltage detection signal; wherein the sodium battery voltage detection signal is configured to indicate the voltages of the n second cells;

[0114] Step S10 specifically includes steps S11 to S12:

[0115] Step S11, outputting a first control signal to the voltage detection control signal input terminal to control the second selection switch circuit to be turned on, obtaining a sodium battery voltage detection signal, and calculating the total voltage of the sodium battery group;

[0116] Step S12: outputting a second control signal that is in phase opposite to the first control signal to the voltage detection control signal input terminal to control the first selection switch circuit to be turned on, obtaining the lithium battery voltage detection signal, and calculating the total voltage of the lithium battery pack.

[0117] In this embodiment, a high-level first control signal is first output to control the second gate switch circuit to conduct. The control module then connects to n sodium batteries, detects the battery voltage of each of the n sodium batteries, and obtains corresponding sodium battery voltage detection signals to obtain n second-cell voltages. These voltages are then added together to calculate the total voltage of the sodium battery pack. Then, a low-level first control signal is output to control the first gate switch circuit to conduct. The control module then connects to n lithium batteries, detects the battery voltage of each of the n lithium batteries, and obtains corresponding lithium battery voltage detection signals to obtain n first-cell voltages. These voltages are then added together to calculate the total voltage of the lithium battery pack. In this way, only one type of battery is connected for testing at a time in this embodiment, reducing interference between different battery types and ensuring more accurate voltage measurements for each battery cell. During testing, only necessary circuit components are activated, reducing unnecessary power consumption and improving system energy efficiency.

[0118] To help understand the implementation principle of this application, please refer to Figure 2 and Figure 3 In one embodiment of the present application, the hybrid battery management circuit further includes a control module. The lithium battery pack includes BL1...BLn, the sodium battery pack includes BN1...BNn, the first switch circuit includes a relay RLL of the lithium battery main circuit, the second switch circuit includes a relay RLN of the sodium battery main circuit, the charge and discharge switch circuit includes a discharge MOS transistor Qd and a charge MOS transistor Qc, the first temperature detection circuit includes a temperature sensor NTCL and a gate switch SNTCL of the lithium battery pack, the second temperature detection circuit includes a temperature sensor NTCN and a gate switch SNTCN of the sodium battery pack, the first current limiting switch circuit includes a bypass relay SRLL and a current limiting resistor RLL1 of the lithium battery, and the second current limiting switch circuit includes a sodium battery. The bypass relay SRLN and the current limiting resistor RLN1 are provided, the NOT gate circuit includes an inverter U3, the first selection switch circuit includes SL1...SL(n+1), the second selection switch circuit includes SN1...SN(n+1), and this embodiment also includes filter resistors RN1...RN(n+1) of the sodium battery pack, filter resistors RL1...RL(n+1) and filter capacitors C1...C(n+1) of the lithium battery pack. The control module includes a power sampling resistor Rs, an analog front-end chip U1, a single-chip microcomputer U2, a power module U4 and a switch SPOW of the power supply input line of U4, an isolated boost power supply U5 and a drive circuit U6, an LDO (Low Dropout Regulator, low voltage difference linear regulator) chip U7, a sleep power supply U8, a charger U9 and a load U10.

[0119] In this embodiment, in response to the charge start instruction / discharge start instruction, the microcontroller U2 is awakened and sends an instruction to close the SPOW switch. The power module U4 is powered on and supplies power to the microcontroller U2 after voltage stabilization by U7. At the same time, after isolation and voltage boosting by U5, the drive circuit U6 is powered on, preparing for U6 to provide drive signals to the charging MOS tube Qc and the discharging MOS tube Qd.

[0120] Next, after acquiring n second cell voltages, U2 outputs a high-level first control signal, closing the second select switches SN1...SN(n+1) and select switch SNTCN, causing the temperature sensor NTCN to output a second temperature detection signal. Simultaneously, the logic NOT gate U3 outputs a low-level signal, opening the first select switches SL1...SL(n+1) and select switch SNTCL. U2 sends instructions to the analog front end U1 to read the voltages of N sodium batteries BN1...BNn and the second ambient temperature. U1 collects the sodium battery voltage detection signals and the second temperature detection signal and reports them to U2. Next, after acquiring n first cell voltages, U2 outputs a low-level second control signal, opening the second select switches SN1...SN(n+1) and select switch SNTCN. Simultaneously, the logic NOT gate U3 outputs a high-level signal, closing the first select switches SL1...SL(n+1) and select switch SNTCL. U2 sends instructions to the analog front end U1 to read the voltages of N lithium batteries BL1...BLn and the first ambient temperature. U1 collects the lithium battery voltage detection signal and the first temperature detection signal and reports them to U2.

[0121] When the response is a charge start command, U2 determines if the first ambient temperature condition is not within the safe charging temperature range for lithium batteries and the second ambient temperature condition is within the safe discharging temperature range for sodium batteries, then controls charging of the sodium battery pack. At this point, U2 outputs a high level to close the second selection switches SN1...SN(n+1) and selection switch SNTCN, while opening the first selection switches SL1...SL(n+1) and selection switch SNTCL. U2 sends a command to U1 to close the charging MOSFET Qc and the discharging MOSFET Qd. Upon receiving this command, U1 drives U6 to output a level signal to close the charging MOSFET Qc and the discharging MOSFET Qd, which in turn closes the charging MOSFET Qc and the discharging MOSFET Qd. Simultaneously, U2 outputs a high level to close the sodium battery main circuit relay RLN, allowing normal charging. If the first ambient temperature condition is within the safe charging temperature range for lithium batteries and the second ambient temperature is within the safe charging temperature range for sodium batteries, then the hybrid charging condition is determined to be met, and step S20 is executed.

[0122] Specifically, microcontroller U2 calculates the total voltage UN1 of the sodium batteries BN1...BNn and the total voltage UL1 of the lithium batteries BL1...BLn, then compares UN1 and UL1. If UL1 > UN1 + ΔV, charging of the sodium battery pack is initiated. U2 outputs a high-level first control signal to establish a sodium battery detection circuit. A low-level output controls the lithium battery main circuit relay RLL to open, while a high-level output controls the sodium battery main circuit relay RLN to close. U2 sends a command to U1 to close the charging MOSFET Qc and the discharging MOSFET Qd. Upon receiving this command, U1 drives U6 to output a level signal to close the charging MOSFET Qc and the discharging MOSFET Qd. U6 then closes the charging MOSFET Qc and the discharging MOSFET Qd. If UN1 > UL1 + ΔV, charging of the lithium battery pack is initiated. U2 outputs a low-level second control signal to establish a lithium battery detection circuit. A high-level output controls the lithium battery main circuit relay RLN to close, while a low-level output controls the sodium battery main circuit relay RLL to open. U6 closes the charging MOSFET Qc and the discharging MOSFET Qd. If -ΔV ≤ UL1 - UL1 ≤ ΔV, the lithium battery pack and the sodium battery pack are charged simultaneously. U2 outputs a low-level second control signal to establish the lithium battery detection circuit and a high-level output to close the sodium battery main circuit relay RLN and the lithium battery main circuit relay RLL. If the voltage of any of the lithium batteries BL1...BLn reaches the full-charge voltage and persists for 2 seconds, charging of the lithium battery pack is stopped by outputting a low-level signal to open the lithium battery main circuit relay RLL. At this point, U2 outputs a high-level first control signal to establish the sodium battery detection circuit and a high-level output to close the second select switches SN1...SN(n+1) and select switch SNTCN, allowing charging to continue. If the voltage of any of the sodium batteries BN1...BNn reaches the full-charge voltage and persists for 2 seconds, charging of the sodium battery pack is stopped, U2 outputs a low-level signal to open the sodium battery main circuit relay RLN, and U6 drives the charging MOSFET Qc and the discharging MOSFET Qd to turn off. At this point, the charging process of the hybrid battery management circuit ends. U2 disconnects the detection loop and outputs a low-level control switch SPOW, which turns off. U2 enters a dormant state and waits for a discharge start instruction to discharge.

[0123] When the response is a discharge start command, U2 determines if the first ambient temperature condition is not within the safe discharge temperature range for lithium batteries and the second ambient temperature condition is within the safe discharge temperature range for sodium batteries, then controls the discharge of the sodium battery pack. At this point, U2 outputs a high-level first control signal to establish a sodium battery detection circuit, closing the second selection switches SN1...SN(n+1) and the selection switch SNTCN, and opening the first selection switches SL1...SL(n+1) and the selection switch SNTCL. U2 sends a command to U1 to close the charging MOSFET Qc and the discharging MOSFET Qd. Upon receiving this command, U1 sends a level signal to U6 to drive the charging MOSFET Qc and the discharging MOSFET Qd to close. U6 then drives the charging MOSFET Qc and the discharging MOSFET Qd to close. At the same time, U2 outputs a high level to close the bypass relay SRLN. During the third preset time, the entire pre-discharge circuit consists of the following components: sodium batteries BN1…BNn, current-limiting resistor RLN, charging MOSFET Qc and discharging MOSFET Qd, load U10, power sampling resistor Rs, and sodium batteries BN1…BNn. After the third preset time expires, U2 outputs a low level to open the bypass relay SRLN and a high level to close the sodium battery main circuit relay RLN, enabling stable discharge. If the first ambient temperature condition is within the safe discharge temperature range for lithium batteries, and the second ambient temperature is also within the safe discharge temperature range for sodium batteries, then the mixed discharge condition is determined to be met, and step S30 is executed.

[0124] Specifically, microcontroller U2 calculates the total voltage UN1 of the sodium batteries BN1...BNn and the total voltage UL1 of the lithium batteries BL1...BLn, and compares UN1 with UL1. If UL1 > UN1 + ΔV, the lithium battery pack is discharged, a low-level second control signal is output to establish a lithium battery detection circuit, and a high-level control signal is output to close the bypass relay SRLL, allowing pre-discharge to proceed for a third preset time. After the third preset time, U2 outputs a low-level control signal to open the bypass relay SRLL and a high-level control signal to close the lithium battery main circuit relay RLL. U6 drives the charging MOSFET Qc and the discharging MOSFET Qd to close. If UN1 > UL1 + ΔV, the sodium battery pack is discharged, U2 outputs a high-level first control signal to establish a sodium battery detection circuit, and a high-level control signal to close the bypass relay SRLN, allowing pre-discharge to proceed for a third preset time. After the third preset time, U2 outputs a low-level control signal to open the bypass relay SRLN and a high-level control signal to close the sodium battery main circuit relay RLN. U6 drives the charging MOSFET Qc and the discharging MOSFET Qd to close. If -ΔV ≤ UL1 - UL1 ≤ ΔV, the lithium battery pack and the sodium battery pack are discharged simultaneously. U2 outputs a low-level second control signal to establish the lithium battery detection circuit and a high-level signal to close the bypass relays SRLN and SRLL, allowing pre-discharge to proceed for a third preset time. After the third preset time, U2 outputs a low-level signal to disconnect the bypass relays SRLN and SRLL, and outputs a high-level signal to close the sodium battery main circuit relays RLN and RLL. Once the voltage of any of the lithium batteries BL1...BLn reaches the empty voltage for two seconds, discharge of the lithium battery pack is stopped by disconnecting the lithium battery main circuit relay RLL. At this point, U2 outputs a high-level first control signal to establish the sodium battery detection circuit, closing the second select switches SN1...SN(n+1) and the select switch SNTCN of the second temperature detection circuit. Once the voltage of any of the sodium batteries BN1...BNn reaches the empty voltage and persists for two seconds, the battery pack is discontinued. U2 outputs a low level to disconnect the main circuit relay RLN, and U6 drives the charging MOSFET Qc and the discharging MOSFET Qd to disconnect. At this point, the hybrid battery management circuit's discharge process ends. U2 disconnects the detection circuit and outputs a low level to disconnect the switch SPOW. U2 enters a dormant state, awaiting a charge start command.

[0125] In this way, this embodiment can balance the voltage between the lithium battery pack and the sodium battery pack and ensure that both types of batteries are in a safe working state throughout the entire charge and discharge cycle, thereby improving the charging and discharging compatibility and safety of the hybrid battery management circuit.

[0126] This application also provides a hybrid battery management circuit, please refer to Figure 2 and Figure 3 The hybrid battery management circuit, applying the control method of the hybrid battery management circuit in the above-mentioned embodiment, can solve the technical problem of the existing hybrid battery management circuit lacking an effective charge and discharge management strategy. Compared with the prior art, the beneficial effects of the hybrid battery management circuit provided in this application are the same as those of the control method of the hybrid battery management circuit provided in the above-mentioned embodiment. The other technical features of the hybrid battery management circuit are the same as those disclosed in the above-mentioned embodiment method, and are not further described here.

[0127] The above description is merely an exemplary embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structural transformation made using the contents of the present application specification and drawings under the technical concept of the present application, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A control method for a hybrid battery management circuit, characterized in that: The hybrid battery management circuit includes a lithium battery group and a sodium battery group, wherein the lithium battery group includes n lithium batteries, and the sodium battery group includes n sodium batteries, and the lithium battery group and the sodium battery group are arranged in parallel. The control method includes: Step S10, obtaining the first cell voltages of n lithium batteries and the second cell voltages of n sodium batteries, and determining the total voltage of the lithium battery pack and the total voltage of the sodium battery pack based on the n first cell voltages and the n second cell voltages; Step S20: When the mixed charging condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, then control the sodium battery pack to be charged; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, then control the lithium battery to be charged; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, then control the lithium battery pack and the sodium battery pack to be charged simultaneously until the voltage of any one of the first cells reaches the full charge voltage of the lithium battery and lasts for a first preset time, then control the lithium battery pack to be stopped from being charged and control the sodium battery pack to be continued to be charged; Step S30: When a mixed discharge condition is met, if the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is greater than a preset difference, the lithium battery group is controlled to be discharged; if the difference between the total voltage of the sodium battery group and the total voltage of the lithium battery group is greater than the preset difference, the sodium battery group is controlled to be discharged; if the absolute value of the difference between the total voltage of the lithium battery group and the total voltage of the sodium battery group is not greater than the preset difference, the lithium battery group and the sodium battery group are controlled to be discharged simultaneously until the voltage of any one of the first cells reaches the lithium battery empty voltage and lasts for a second preset time, at which time the lithium battery group is controlled to stop discharging and the sodium battery group is controlled to continue discharging; Before step S20, the control method further includes: In response to a charge start instruction, obtaining an ambient temperature of an area where the lithium battery pack and the sodium battery pack are located; If the ambient temperature is not within the safe charging temperature range of the lithium battery but is within the safe charging temperature range of the sodium battery, controlling the sodium battery pack to be charged; If the ambient temperature is within the safe charging temperature range of the lithium battery and the safe charging temperature range of the sodium battery, it is determined that the mixed charging condition is met, and step S20 is executed; Before step S30, the control method further includes: In response to a discharge start instruction, obtaining an ambient temperature of an area where the lithium battery pack and the sodium battery pack are located; If the ambient temperature is not within the safe discharge temperature range of the lithium battery but is within the safe discharge temperature range of the sodium battery, controlling the sodium battery pack to discharge; If the ambient temperature is within the safe discharge temperature range of the lithium battery and the safe discharge temperature range of the sodium battery, it is determined that the mixed discharge condition is met, and step S30 is executed.

2. The control method of the hybrid battery management circuit according to claim 1, characterized in that: The hybrid battery management circuit further includes: a first switch circuit, the first switch circuit being connected to the lithium battery pack, the first switch circuit being configured to connect the lithium battery pack when turned on, and disconnect the lithium battery pack when turned off; a second switch circuit, the second switch circuit being connected to the first switch circuit and the sodium battery pack, respectively, the second switch circuit being configured to connect the sodium battery pack when turned on and disconnect the sodium battery pack when turned off; a charge-discharge switch circuit, the charge-discharge switch circuit being connected to the first switch circuit and the second switch circuit respectively, the charge-discharge switch circuit being further configured to be connected to an external charging input terminal or a load, the charge-discharge switch circuit being configured to start charging and discharging the lithium battery and / or the sodium battery when turned on, and to stop charging and discharging the lithium battery and / or the sodium battery when turned off; The step S20 specifically includes: Step S21: When the mixed charging condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the first switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first switch circuit, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on, until the voltage of any one of the first cells reaches the full charge voltage of the lithium battery and lasts for the first preset time, at which time the first switch circuit is controlled to be turned off.

3. The control method of the hybrid battery management circuit according to claim 2, characterized in that: The step S30 specifically includes: Step S31: When a mixed discharge condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the first switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on; if the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first switch circuit, the second switch circuit and the charge-discharge switch circuit are controlled to be turned on, until the voltage of any one of the first cells reaches the lithium battery empty voltage and lasts for the second preset time, at which time the first switch circuit is controlled to be turned off.

4. The control method of the hybrid battery management circuit according to claim 3, characterized in that: The hybrid battery management circuit further includes: a first temperature detection circuit, which is disposed near the lithium battery pack and is configured to detect a first ambient temperature of an area where the lithium battery pack is located and output a corresponding first temperature detection signal; a second temperature detection circuit, the second temperature detection circuit being disposed close to the sodium battery pack and configured to detect a second ambient temperature of an area where the sodium battery pack is located and output a corresponding second temperature detection signal; Before step S20, the control method further includes: When the charge-discharge switch circuit is connected to the external charging input terminal, in response to the charge start instruction, obtaining the first temperature detection signal and the second temperature detection signal, and determining the first ambient temperature according to the first temperature detection signal, and determining the second ambient temperature according to the second temperature detection signal; If the first ambient temperature is not within the safe charging temperature range of the lithium battery, and the second ambient temperature is within the safe charging temperature range of the sodium battery, controlling the second switch circuit to be connected to the charge and discharge switch circuit; If the first ambient temperature is within the safe charging temperature range of the lithium battery and the second ambient temperature is within the safe charging temperature range of the sodium battery, it is determined that the mixed charging condition is met and step S21 is executed.

5. The control method of the hybrid battery management circuit according to claim 4, characterized in that: Before step S30, the control method further includes: When the charge-discharge switch circuit is connected to a load, in response to a discharge start instruction, obtaining the first temperature detection signal and the second temperature detection signal, and determining the first ambient temperature according to the first temperature detection signal, and determining the second ambient temperature according to the second temperature detection signal; If the first ambient temperature is not within the safe discharge temperature range of the lithium battery, and the second ambient temperature is within the safe discharge temperature range of the sodium battery, controlling the second switch circuit to be connected to the charge and discharge switch circuit; If the first ambient temperature is within the safe discharge temperature range of the lithium battery and the second ambient temperature is within the safe discharge temperature range of the sodium battery, it is determined that the mixed discharge condition is met and step S31 is executed.

6. The control method of the hybrid battery management circuit according to claim 3, characterized in that: The hybrid battery management circuit further includes: a first current limiting switch circuit, the first current limiting switch circuit being connected to the lithium battery pack and the charge and discharge switch circuit, respectively, the first current limiting switch circuit being configured to connect to the lithium battery pack when turned on and limit the discharge current of the lithium battery pack, and to disconnect the lithium battery pack when turned off; a second current limiting switch circuit, the second current limiting switch circuit being connected to the sodium battery pack and the charge and discharge switch circuit, respectively, the second current limiting switch circuit being configured to connect to the sodium battery pack when turned on and limit the discharge current of the sodium battery pack, and to disconnect the sodium battery pack when turned off; The step S31 includes: When the mixed discharge condition is met, if the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is greater than a preset difference, the first current limiting switch circuit and the charge-discharge switch circuit are controlled to be turned on, and after a third preset time, the first current limiting switch circuit is turned off and the first switch circuit is turned on. If the difference between the total voltage of the sodium battery pack and the total voltage of the lithium battery pack is greater than the preset difference, the second current limiting switch circuit and the charge-discharge switch circuit are controlled to be turned on, and after the third preset time, the second current limiting switch circuit is turned off and the second switch circuit is turned on. If the absolute value of the difference between the total voltage of the lithium battery pack and the total voltage of the sodium battery pack is not greater than the preset difference, the first current limiting switch circuit, the second current limiting switch circuit, and the charge-discharge switch circuit are controlled to be turned on, and after the third preset time, the first current limiting switch circuit and the second current limiting switch circuit are turned off, and the first switch circuit and the second switch circuit are turned on. This process continues until the voltage of any one of the first cells reaches the lithium battery discharge voltage and lasts for the second preset time, at which point the first switch circuit is controlled to be turned off.

7. The control method of the hybrid battery management circuit according to claim 2, characterized in that: The hybrid battery management circuit further includes: Voltage detection control signal input terminal; a NOT gate circuit, wherein an input terminal of the NOT gate circuit is connected to the voltage detection control signal input terminal; a first gating switch circuit, the first gating switch circuit being connected to n of the lithium batteries, the controlled end of the first gating switch circuit being connected to the output end of the NOT gate circuit, the first gating switch circuit being configured to connect the n lithium batteries when turned on to output a lithium battery voltage detection signal, and to disconnect the n lithium batteries when turned off to stop outputting the lithium battery voltage detection signal; wherein the lithium battery voltage detection signal is configured to indicate the voltages of the n first cells; a second gate switch circuit, the second gate switch circuit being connected to the n sodium batteries, the controlled terminal of the second gate switch circuit being connected to the voltage detection control signal input terminal, the second gate switch circuit being configured to connect the n sodium batteries to output a sodium battery voltage detection signal when turned on, and disconnect the n sodium batteries to stop outputting the sodium battery voltage detection signal when turned off; wherein the sodium battery voltage detection signal is configured to indicate the voltages of the n second cells; The step S10 specifically includes: Outputting a first control signal to the voltage detection control signal input terminal to control the second selection switch circuit to be turned on, obtaining the sodium battery voltage detection signal, and calculating the total voltage of the sodium battery group; Output a second control signal that is in phase with the first control signal to the voltage detection control signal input terminal to control the first selection switch circuit to be turned on, obtain the lithium battery voltage detection signal, and calculate the total voltage of the lithium battery pack.

8. A hybrid battery management circuit, characterized in that: A control method for a hybrid battery management circuit according to any one of claims 1 to 7 is applied.

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