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

Abstract

The invention discloses a control method of a hybrid battery management circuit and the hybrid battery management circuit, and relates to the technical field of battery management. The control method comprises the following steps: during charging, if the total voltage of the lithium battery pack is obviously higher, charging the sodium battery pack, if the total voltage of the sodium battery pack is obviously higher, charging the lithium battery pack, and if the total voltages of the sodium battery pack and the lithium battery pack are close, charging the sodium battery pack and the lithium battery pack at the same time until the single voltage of any lithium battery reaches a full charge voltage and lasts for a first preset time; and the lithium battery pack is controlled to stop charging. During discharging, if the total voltage of the lithium battery pack is obviously higher, discharging the lithium battery pack, if the total voltage of the sodium battery pack is obviously higher, discharging the sodium battery pack, and if the total voltages of the lithium battery pack and the sodium battery pack are close, discharging the lithium battery pack and the sodium battery pack at the same time until the monomer voltage of any lithium battery reaches an emptying voltage and lasts for a second preset time; the lithium battery pack is firstly controlled to stop discharging. The charging and discharging compatibility and safety of different types of batteries can be improved.

Description

Technical Field

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

[0002] As the global demand for clean energy and efficient energy storage systems continues to grow, hybrid battery systems have received widespread attention as a solution that can combine the advantages of multiple battery technologies. Among them, connecting different types of batteries (such as lithium batteries and sodium batteries) in parallel has become an effective way to improve the performance of energy storage systems. This configuration can not only take advantage of the advantages of each battery type, such as the high energy density of lithium batteries and the cost-effectiveness of sodium batteries, but also achieve 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 the present 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 charging and discharging performance of the hybrid battery management circuit.

[0005] To achieve the above object, the present application proposes a control method for a hybrid battery management circuit, wherein the hybrid battery management circuit comprises a lithium battery group and a sodium battery group, wherein the lithium battery group and the sodium battery group are arranged in parallel, and the control method comprises:

[0006] Step S10, obtaining the first cell voltages of the n lithium batteries and the second cell voltages of the n sodium batteries, and determining the total voltage of the lithium battery group and the total voltage of the sodium battery group according to 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 group and the total voltage of the sodium battery group is greater than a preset difference, the sodium battery group is controlled 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, the lithium battery is controlled 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, the lithium battery group and the sodium battery group are controlled to be charged simultaneously until any one of the first single-cell voltages reaches the full charge voltage of the lithium battery and lasts for a first preset time, the lithium battery group is controlled to stop charging, and the sodium battery group is controlled to continue charging;

[0008] 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 one of the first single cell voltages reaches the lithium battery emptying voltage and lasts for a second preset time, 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 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 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 performed.

[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 used 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 used to connect the sodium battery pack when being turned on, and disconnect the connection of the sodium battery pack when being turned off;

[0020] A charge and discharge switch circuit, wherein the charge and discharge switch circuit is connected to the first switch circuit and the second switch circuit respectively, and the charge and discharge switch circuit is also used to connect to an external charging input terminal or a load, and the charge and discharge switch circuit is used to start the charge and discharge of the lithium battery and / or the sodium battery when it is turned on, and stop the charge and discharge of the lithium battery and / or the sodium battery when it is 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 group and the total voltage of the sodium battery group is greater than a preset difference, the second switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 first switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 first switch circuit, the second switch circuit and the charge and discharge switch circuit are controlled to be turned on, until any one of the first monomer voltages reaches the full charge voltage of the lithium battery and lasts for the first preset time, and the first switch circuit is controlled to be turned off.

[0023] In one implementation, the step S30 specifically includes:

[0024] Step S31: 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 first switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 second switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 first switch circuit, the second switch circuit and the charge and discharge switch circuit are controlled to be turned on, until any one of the first monomer voltages reaches the lithium battery empty voltage and lasts for the second preset time, and 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 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;

[0027] a second temperature detection circuit, which is disposed close to the sodium battery pack and is used 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 an external charging input terminal, in response to the charging start instruction, the first temperature detection signal and the second temperature detection signal are acquired, and the first ambient temperature is determined according to the first temperature detection signal, and the second ambient temperature is determined 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 hybrid 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, the first temperature detection signal and the second temperature detection signal are acquired, and the first ambient temperature is determined according to the first temperature detection signal, and the second ambient temperature is determined 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 used to connect to the lithium battery pack when being turned on and limit the discharge current of the lithium battery pack, and to disconnect the lithium battery pack when being turned off;

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

[0039] The step S31 comprises:

[0040] 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 the preset difference, the first current limiting switch circuit is controlled to be turned on with the charge and discharge switch circuit, and after the 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 group and the total voltage of the lithium battery group is greater than the preset difference, the second current limiting switch circuit is controlled to be turned on with the charge and discharge switch circuit, 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 group and the total voltage of the sodium battery group is not greater than the preset difference, the first current limiting switch circuit, the second current limiting switch circuit and the charge and 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, until any one of the first monomer voltages reaches the lithium battery empty voltage and lasts for the second preset time, and 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, wherein the first gating switch circuit is connected to n of the lithium batteries, a controlled end of the first gating switch circuit is connected to an output end of the NOT gate circuit, the first gating switch circuit is used to connect the n lithium batteries when turned on to output a lithium battery voltage detection signal, and 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 used to indicate the voltage of the n first monomers;

[0045] a second gating switch circuit, wherein the second gating switch circuit is connected to the n sodium batteries, the controlled end of the second gating switch circuit is connected to the voltage detection control signal input end, the second gating switch circuit is used to connect the n sodium batteries when it is turned on to output a sodium battery voltage detection signal, and disconnect the n sodium batteries when it is turned off to stop outputting the sodium battery voltage detection signal; wherein the sodium battery voltage detection signal is used to indicate the voltage of the n second monomers;

[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] A second control signal which is inverted with the first control signal is output 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, and the hybrid battery management circuit 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 of a hybrid battery management circuit, which includes: step S10, obtaining the first single-cell voltage of n lithium batteries and the second single-cell voltage of n sodium batteries, and determining the total voltage of the lithium battery group and the total voltage of the sodium battery group according to the n first single-cell voltages and the n second single-cell voltages. Step S20, when the hybrid 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 the 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 one of the first single-cell voltages reaches the full charge voltage of the lithium battery and lasts for the first preset time, then control the lithium battery group to stop charging, and control the sodium battery group to continue charging. 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 the 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 single cell voltage reaches the lithium battery empty voltage and lasts for a second preset 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 the two types of batteries are in a safe working state throughout the entire charge and discharge cycle, and can improve the compatibility and safety of the hybrid battery management circuit for charging and discharging. 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 A schematic flow chart of an embodiment of a control method for a hybrid battery management circuit provided in the present application;

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

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

[0055] The realization of the purpose, 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 the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work 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 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 only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. 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 batteries and sodium batteries, the existing hybrid battery management circuit lacks an effective charging and discharging management strategy, which reduces the performance of the overall battery system. Specifically, the safe charging temperature range of lithium batteries is 0℃~45℃, the safe discharging temperature range of lithium batteries is -10℃~50℃, the safe charging temperature range of sodium batteries is -20℃~70℃, and the safe discharging temperature range of sodium batteries is -30℃~70℃. 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 empty voltage of a single lithium battery is 2.5V, and the empty voltage of a single sodium battery is 2.2V.

[0060] The present application provides 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 a total voltage of the lithium battery group and a total voltage of the sodium battery group according to 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 the preset difference, the sodium battery group is controlled 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, the lithium battery is controlled 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, the lithium battery group and the sodium battery group are controlled to be charged simultaneously, until any one of the first single cell voltages reaches the full charge voltage of the lithium battery and lasts for a first preset time, the lithium battery group is controlled to stop charging, and the sodium battery group is controlled 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 the 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 one of the first single cell voltages reaches the lithium battery emptying voltage and lasts for a second preset 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 the lithium battery pack is the total voltage obtained by superimposing the voltages of n first cells, and the total voltage of the sodium battery pack is the total voltage obtained by superimposing the voltages of n second cells. The mixed charging condition may be conditions such as the ambient temperature range, the battery health status, or the stability of the power supply, and the mixed discharge condition may be conditions such as the ambient temperature range, the battery health status, or the load demand, which are not limited here. For example, when the ambient temperature is between 0°C and 45°C, the ambient temperature is within the common safe charging temperature range of the lithium battery and the sodium battery, then the two types of batteries can be considered to meet the mixed charging conditions, and step S20 can be executed. When the ambient temperature is between -10°C and 50°C, the ambient temperature is within the common safe discharge temperature range of the lithium battery and the sodium battery, then the two types of batteries can be considered to meet the mixed discharge conditions, and step S30 can be executed.

[0066] In this embodiment, 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 the preset difference, it means that the total voltage of the lithium battery group is significantly higher than the total voltage of the sodium battery group. In order to balance the voltage between the lithium battery group and the sodium battery group during the charging process, 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 the preset difference, it means that the total voltage of the sodium battery group is significantly higher than the total voltage of the lithium battery group. In order to balance the voltage between the lithium battery group and the sodium battery group during the charging process, 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 means that the total voltage of the lithium battery is close to the total voltage of the sodium battery, and the lithium battery group and the sodium battery group are in a voltage balance state, then the lithium battery group and the sodium battery group are controlled to be charged at the same time. 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 batteries in the lithium battery group and the sodium battery group is n, during the synchronous charging process of the lithium battery group and the sodium battery group, the lithium battery group is fully charged before the sodium battery group. When the voltage of any first single cell reaches the full charge voltage of the lithium battery and lasts for the first preset time, for example, when it reaches 3.7V and lasts for 2 seconds, it can be considered that the lithium battery group is in a fully charged state. At this time, the lithium battery group is controlled to stop charging to prevent the lithium battery group from being in an overcharged state, and the sodium battery group is continued to be controlled to be charged. Similarly, when the voltage of any second single cell reaches the full charge voltage of the sodium battery and lasts for the first preset time, for example, when it reaches 4.0V and lasts for 2 seconds, it is considered that the sodium battery group is in a fully charged state. At this time, the sodium battery group is controlled to stop charging. Therefore, in a feasible implementation manner, after the step of controlling the lithium battery pack to stop charging and controlling the sodium battery pack to continue charging until any first single cell voltage 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 any second single cell voltage reaches the full charge voltage of the lithium battery and lasts for the first preset time.

[0067] In this embodiment, 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 the preset difference, it means that the total voltage of the lithium battery group is significantly higher than the total voltage of the sodium battery group. In order to balance the voltage between the lithium battery group and the sodium battery group during the discharge process, the lithium battery group is first 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, it means that the total voltage of the sodium battery group is significantly higher than the total voltage of the lithium battery group. In order to balance the voltage between the lithium battery group and the sodium battery group during the discharge process, the sodium battery group is first 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, it means that the total voltage of the lithium battery is relatively close to the total voltage of the sodium battery, and the lithium battery group and the sodium battery group are in a voltage balance state, then the lithium battery group and the sodium battery group are simultaneously controlled to be discharged. It is understandable 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 batteries in the lithium battery group and the sodium battery group is n, during the synchronous discharge process of the lithium battery group and the sodium battery group, the lithium battery group reaches the fully discharged state before the sodium battery group. When the voltage of any first single cell reaches the empty voltage of the lithium battery and lasts for the first preset time, for example, when it reaches 2.5V and lasts for 2 seconds, it is considered that the lithium battery group is in a fully discharged state. At this time, the lithium battery group is controlled to stop discharging to prevent the lithium battery group from being in an over-discharge state, and the sodium battery group is continued to be controlled to discharge. Similarly, when the voltage of any second single cell reaches the empty voltage of the sodium battery and lasts for the first preset time, for example, when it reaches 2.5V and lasts for 2 seconds, it can be considered that the sodium battery group is in a fully discharged state. At this time, the sodium battery group is controlled to stop discharging. Therefore, in another feasible implementation manner, after the steps of controlling the lithium battery pack to stop discharging until any one of the first single-cell voltages reaches the empty voltage of the lithium battery and lasts for the 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 any one of the second single-cell voltages reaches the empty voltage of the sodium battery and lasts for the 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 prior art, the control method of this embodiment can balance the voltage between the lithium battery group and the sodium battery group and ensure that they are in a safe working state throughout the entire charging and discharging cycle, which can improve the compatibility and safety of the hybrid battery management circuit for charging and discharging.

[0069] In the present application, the control method of the hybrid battery management circuit includes: step S10, obtaining the first single-cell voltages of n lithium batteries and the second single-cell voltages of n sodium batteries, and determining the total voltage of the lithium battery group and the total voltage of the sodium battery group according to the n first single-cell voltages and the n second single-cell voltages. Step S20, when the hybrid 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 the preset difference, then control the charging of the sodium battery group; 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 charging of the lithium battery; 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 simultaneous charging of the lithium battery group and the sodium battery group, until any one of the first single-cell voltages reaches the full charge voltage of the lithium battery and lasts for a first preset time, then control the charging of the lithium battery group to stop, and control the charging of the sodium battery group to continue. 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 the 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 one of the first single cell voltages reaches the lithium battery empty voltage and lasts for a second preset 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 the two types of batteries are in a safe working state throughout the entire charge and discharge cycle, and can improve the compatibility and safety of the hybrid battery management circuit for charging and discharging.

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

[0071] Step S01, in response to a charging 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 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 hybrid 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 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. When charging is performed, if the ambient temperature is not between -20°C (including -20°C) and 0°C (excluding 0°C) or between 45°C (excluding 45°C) and 70°C (including 70°C), the ambient temperature is not within the safe charging temperature range of 0°C to 45°C for lithium batteries, but within the safe charging temperature range of -20°C to 70°C for sodium batteries, so the sodium battery pack is controlled to be charged. 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 step executes steps S10 and S20 to ensure the safety of the charging process.

[0079] When performing discharge, if the ambient temperature is not in the range of -30°C (including -30°C) to -10°C (excluding -10°C) or 50°C (excluding 50°C) to 70°C (including 70°C), the ambient temperature is not in the safe discharge temperature range of -10°C to 50°C for lithium batteries, but is in the safe charging temperature range of -30°C to 70°C for sodium batteries, so the sodium battery pack is controlled to be discharged. If the ambient temperature is in the range of -10°C to 50°C, the ambient temperature is in 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 step S10 and step S30, thereby 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 is connected to the lithium battery pack, and the first switch circuit is used to connect the lithium battery pack when it is turned on, and disconnect the lithium battery pack when it is 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 used to connect the sodium battery pack when being turned on, and disconnect the connection of the sodium battery pack when being turned off;

[0083] A charge and discharge switch circuit, the charge and discharge switch circuit is connected to the first switch circuit and the second switch circuit respectively, the charge and discharge switch circuit is also used to connect to an external charging input terminal or a load, and the charge and discharge switch circuit is used to start the charge and discharge of the lithium battery and / or the sodium battery when it is turned on, and stop the charge and discharge of the lithium battery and / or the sodium battery when it is 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 group and the total voltage of the sodium battery group is greater than the preset difference, the second switch circuit and the charge and discharge switch circuit are controlled to be turned on; 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 first switch circuit and the charge and discharge switch circuit are controlled to be turned on; 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 first switch circuit, the second switch circuit and the charge and discharge switch circuit are controlled to be turned on, until any one of the first monomer voltages reaches the full charge voltage of the lithium battery and lasts for the first preset time, and 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 group and the total voltage of the sodium battery group is greater than the preset difference, the first switch circuit and the charge and discharge switch circuit are controlled to be turned on; 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 second switch circuit and the charge and discharge switch circuit are controlled to be turned on; 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 first switch circuit, the second switch circuit and the charge and discharge switch circuit are controlled to be turned on, until any one of the first monomer voltages reaches the lithium battery empty voltage and lasts for the second preset time, and the first switch circuit is controlled to be turned off.

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

[0089] In a feasible implementation manner, after the step of controlling the first switch circuit to be turned off 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, the control method further includes: controlling the second switch circuit and the charge and discharge switch circuit to be turned 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 implementation manner, after the step of controlling the first switch circuit to turn off until any one of the first monomer voltages 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 and discharge switch circuit to turn off until any one of the second monomer voltages 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 arranged 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 close to 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 the charging start instruction, a first temperature detection signal and a second temperature detection signal are obtained, and a first ambient temperature is determined according to the first temperature detection signal, and a second ambient temperature is determined 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 to be turned on with the charge and discharge switch circuit;

[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 the load, in response to the 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, then controlling the second switch circuit to be turned on with the charge and discharge switch circuit;

[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 result is 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 is connected to the lithium battery pack and the charge and discharge switch circuit respectively, the first current limiting switch circuit is used to connect the lithium battery pack when it is turned on and limit the discharge current of the lithium battery pack, and disconnect the lithium battery pack when it is turned off;

[0105] a second current limiting switch circuit, the second current limiting switch circuit being connected to the sodium battery group and the charge and discharge switch circuit respectively, the second current limiting switch circuit being used to connect to the sodium battery group when being turned on and limit the discharge current of the sodium battery group, and to disconnect the connection of the sodium battery group when being 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 group and the total voltage of the sodium battery group is greater than the preset difference, the first current limiting switch circuit and the charge and discharge switch circuit are controlled to be turned on, and after the 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 group and the total voltage of the lithium battery group is greater than the preset difference, the second current limiting switch circuit and the charge and 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 group and the total voltage of the sodium battery group is not greater than the preset difference, the first current limiting switch circuit, the second current limiting switch circuit and the charge and 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, until any one of the first monomer voltages reaches the lithium battery empty voltage and lasts for the second preset time, and the first switch circuit is controlled to be turned off.

[0108] It should be noted that, during the initial discharge process of the battery, due to the low internal impedance of the battery, a large instantaneous current is easily generated, thereby causing circuit damage or triggering a circuit protection mechanism, which is not conducive to the safe discharge process. In this embodiment, by connecting the first current limiting switch circuit in parallel with the first switch circuit, during the initial discharge process of the lithium battery, the initial current is limited by the first current limiting switch circuit, thereby improving the safety of the lithium battery discharge. By connecting the second current limiting switch circuit in parallel with the second switch circuit, during the initial discharge process of the sodium battery, the initial current is limited by the second current limiting switch circuit, thereby improving the safety of the 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 gating switch circuit, the first gating switch circuit is connected to n lithium batteries, the controlled end of the first gating switch circuit is connected to the output end of the NOT gate circuit, the first gating switch circuit is used to connect the n lithium batteries when it is turned on to output a lithium battery voltage detection signal, and disconnect the n lithium batteries when it is turned off to stop outputting the lithium battery voltage detection signal; wherein the lithium battery voltage detection signal is used to indicate the voltages of the n first cells;

[0113] a second gating switch circuit, the second gating switch circuit is connected to n sodium batteries, a controlled end of the second gating switch circuit is connected to a voltage detection control signal input end, the second gating switch circuit is used to connect the n sodium batteries when it is turned on to output a sodium battery voltage detection signal, and disconnect the n sodium batteries when it is turned off to stop outputting the sodium battery voltage detection signal; wherein the sodium battery voltage detection signal is used to indicate the voltages of the n second monomers;

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

[0115] Step S11, outputting a first control signal to a 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 a total voltage of the sodium battery group;

[0116] Step S12, outputting a second control signal which is inverted with 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 can be output first to control the second gate switch circuit to be turned on, and then the control module is connected to n sodium batteries, and the battery voltage of each of the n sodium batteries can be detected, and the corresponding sodium battery voltage detection signal can be obtained to obtain n second single-cell voltages, and then the total voltage of the sodium battery group is obtained by superposition calculation. Then, a low-level first control signal is output to control the first gate switch circuit to be turned on, and then the control module is connected to n lithium batteries, and the battery voltage of each of the n lithium batteries can be detected, and the corresponding lithium battery voltage detection signal can be obtained to obtain n first single-cell voltages, and then the total voltage of the lithium battery group is obtained by superposition calculation. In this way, in this embodiment, only one type of battery is connected for detection at a time, which can reduce mutual interference between different battery types and ensure that the voltage measurement of each battery single cell is more accurate. When performing detection, only necessary circuit parts are activated, which reduces unnecessary power consumption and improves the energy efficiency of the system.

[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 also 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 tube Qd and a charge MOS tube Qc, the first temperature detection circuit includes a temperature sensor NTCL of the lithium battery pack and a gate switch SNTCL, the second temperature detection circuit includes a temperature sensor NTCN of the sodium battery pack and a gate switch SNTCN, 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, 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), the present embodiment also includes the filter resistor RN1...RN(n+1) of the sodium battery pack, the filter resistor RL1...RL(n+1) and the filter capacitor 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 single-chip computer U2 is awakened, and an instruction is sent to close the SPOW switch, and the power module U4 is powered on. After voltage stabilization by U7, the single-chip computer U2 is powered on. 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] Then, the voltages of n second monomers are obtained, U2 outputs a high-level first control signal, controls the second selection switch SN1...SN(n+1) and the selection switch SNTCN to be closed, and the temperature sensor NTCN outputs a second temperature detection signal. At the same time, the logic NOT gate U3 outputs a low level, and the first selection switch SL1...SL(n+1) and the selection switch SNTCL are in an open state. U2 sends an instruction to read the voltages of N sodium batteries BN1...BNn and read the second ambient temperature to the analog front end U1. U1 collects the sodium battery voltage detection signal and the second temperature detection signal and reports them to U2. Next, the voltages of n first monomers are obtained, and U2 outputs a low-level second control signal, controls the second selection switch SN1...SN(n+1) and the selection switch SNTCN to be opened. At the same time, the logic NOT gate U3 outputs a high level, and the first selection switch SL1...SL(n+1) and the selection switch SNTCL are in a closed state. U2 sends an instruction to read the voltages of N lithium batteries BL1...BLn and the first ambient temperature to the analog front end U1. 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 charging start instruction, U2 makes a judgment at this time. If the first ambient temperature condition is not within the safe charging temperature range of the lithium battery, and the second ambient temperature is within the safe discharging temperature range of the sodium battery, then the sodium battery pack is controlled to be charged. At this time, U2 outputs a high level to control the second selection switch SN1...SN(n+1) and the selection switch SNTCN to be closed, and the first selection switch SL1...SL(n+1) and the selection switch SNTCL to be opened. U2 sends an instruction to close the charging MOS tube Qc and the discharging MOS tube Qd to U1. After receiving the instruction, U1 drives U6 to output a level signal to close the charging MOS tube Qc and the discharging MOS tube Qd, and U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to be closed. At the same time, U2 outputs a high level to control the sodium battery main circuit relay RLN to be closed, and normal charging can be performed at this time. If the first ambient temperature condition 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 S20 is executed.

[0122] Specifically, the single-chip computer U2 calculates the total voltage UN1 of the sodium battery BN1 ... BNn, calculates the total voltage UL1 of the lithium battery BL1 ... BLn, and compares the size of UN1 and UL1. If UL1>UN1+△V, then the sodium battery pack is controlled to be charged, and U2 outputs a high-level first control signal to establish a sodium battery detection circuit, and outputs a low-level to control the lithium battery main circuit relay RLL to be disconnected, and outputs a high-level to control the sodium battery main circuit relay RLN to be closed. U2 sends an instruction to close the charging MOS tube Qc and the discharging MOS tube Qd to U1. After receiving the instruction, U1 drives U6 to output a level signal to close the charging MOS tube Qc and the discharging MOS tube Qd, and U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to be closed. If UN1>UL1+△V, then the lithium battery pack is controlled to be charged, and U2 outputs a low-level second control signal to establish a lithium battery detection circuit, and outputs a high-level to control the lithium battery main circuit relay RLN to be closed, and outputs a low-level to control the sodium battery main circuit relay RLL to be disconnected. U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to be closed. If -△V≤UL1-UL1≤△V, the lithium battery group and the sodium battery group are controlled to be charged simultaneously, and U2 outputs a low-level second control signal to establish a lithium battery detection circuit, and outputs a high level to control the sodium battery main circuit relay RLN to be closed, and outputs a high level to control the lithium battery main circuit relay RLL to be closed. Until it is detected that the voltage of any one of the lithium batteries BL1...BLn reaches the full charge voltage of the lithium battery and lasts for 2 seconds, the lithium battery group is controlled to stop charging, that is, the lithium battery main circuit relay RLL is controlled to be disconnected by outputting a low level. At this time, U2 outputs a high-level first control signal to establish a sodium battery detection circuit, and outputs a high level to control the second selection switch SN1...SN(n+1) and the selection switch SNTCN to be closed to continue charging. Until it is detected that the voltage of any one of the sodium batteries BN1...BNn reaches the full charge voltage of the sodium battery and lasts for 2 seconds, the sodium battery group is controlled to stop charging, U2 outputs a low level to control the sodium battery main circuit relay RLN to be disconnected, and U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to be disconnected. At this point, the charging process of the hybrid battery management circuit ends. U2 disconnects the detection loop, and the output low level control switch SPOW is disconnected, and U2 enters a dormant state, waiting for a discharge start instruction to discharge.

[0123] When the response is a discharge start instruction, U2 makes a judgment at this time. If the first ambient temperature condition 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, then the sodium battery pack is controlled to be discharged. At this time, U2 outputs a high-level first control signal to establish a sodium battery detection circuit, controls the second selection switch SN1...SN(n+1) and the selection switch SNTCN to be closed, and the first selection switch SL1...SL(n+1) and the selection switch SNTCL to be opened. U2 sends an instruction to U1 to close the charging MOS tube Qc and the discharging MOS tube Qd. After receiving the instruction, U1 drives the level signal of the charging MOS tube Qc and the discharging MOS tube Qd to U6 to close. U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to be closed. At the same time, U2 outputs a high level to control the bypass relay SRLN to close. Within the third preset time, the entire pre-discharge circuit is: sodium battery BN1...BNn, current limiting resistor RLN, charging MOS tube Qc and discharging MOS tube Qd, load U10, Rs power sampling resistor, sodium battery BN1...BNn. After the third preset time, U2 outputs a low level to control the bypass relay SRLN to open, and outputs a high level to control the sodium battery main circuit relay RLN to close, and stable discharge can be achieved at this time. If the first ambient temperature condition 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 S30 is executed.

[0124] Specifically, the single-chip computer U2 calculates the total voltage UN1 of the sodium batteries BN1...BNn, calculates the total voltage UL1 of the lithium batteries BL1...BLn, and compares the size of UN1 and UL1. If UL1>UN1+△V, the lithium battery pack is controlled to be discharged, and a low-level second control signal is output to establish a lithium battery detection circuit, and a high-level control bypass relay SRLL is output to close, and pre-discharge is performed within a third preset time. After the third preset time, U2 outputs a low-level control bypass relay SRLL to disconnect, and outputs a high-level control lithium battery main circuit relay RLL to close. U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to close. If UN1>UL1+△V, the sodium battery pack is controlled to be discharged, and U2 outputs a high-level first control signal to establish a sodium battery detection circuit, and outputs a high-level control bypass relay SRLN to close, and pre-discharge is performed within a third preset time. After the third preset time, U2 outputs a low-level control bypass relay SRLN to disconnect, and outputs a high-level control sodium battery main circuit relay RLN to close. U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to close. If -△V≤UL1-UL1≤△V, the lithium battery group and the sodium battery group are controlled to discharge simultaneously, U2 outputs a low-level second control signal to establish a lithium battery detection circuit, and outputs a high-level control bypass relay SRLN and SRLL to close, and pre-discharge is performed within the third preset time. After the third preset time, U2 outputs a low-level control bypass relay SRLN and SRLL to disconnect, and outputs a high-level control sodium battery main circuit relay RLN and lithium battery main circuit relay RLL to close. Until it is detected that the voltage of any lithium battery among the lithium batteries BL1...BLn reaches the lithium battery emptying voltage and lasts for 2 seconds, the lithium battery group is controlled to stop discharging, that is, the low-level control main circuit relay RLL of the lithium battery is disconnected. At this time, U2 outputs a high-level first control signal to establish a sodium battery detection circuit, and controls the second selection switch SN1...SN(n+1) and the selection switch SNTCN of the second temperature detection circuit to close. Until it is detected that the voltage of any sodium battery among the sodium batteries BN1...BNn reaches the sodium battery empty voltage and lasts for 2 seconds, the sodium battery group is controlled to stop discharging, U2 outputs a low level to control the sodium battery main circuit relay RLN to disconnect, and U6 drives the charging MOS tube Qc and the discharging MOS tube Qd to disconnect. At this point, the discharge process of the hybrid battery management circuit ends, U2 disconnects the detection circuit, and outputs a low level to control the switch SPOW to disconnect, and U2 enters a dormant state, waiting for the charging start instruction to charge.

[0125] In this way, this embodiment can balance the voltage between the lithium battery group and the sodium battery group and ensure that the two 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 applies the control method of the hybrid battery management circuit in the above embodiment, which can solve the technical problem that the existing hybrid battery management circuit lacks an effective charge and discharge management strategy. Compared with the prior art, the beneficial effects of the hybrid battery management circuit provided by the present application are the same as the beneficial effects of the control method of the hybrid battery management circuit provided by the above embodiment, and other technical features in the hybrid battery management circuit are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0127] The above description is only an exemplary embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural changes made by 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 are 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, 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 includes: Step S10, obtaining the first cell voltages of the n lithium batteries and the second cell voltages of the n sodium batteries, and determining the total voltage of the lithium battery group and the total voltage of the sodium battery group according to 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 group and the total voltage of the sodium battery group is greater than a preset difference, the sodium battery group is controlled 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, the lithium battery is controlled 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, the lithium battery group and the sodium battery group are controlled to be charged simultaneously until any one of the first single-cell voltages reaches the full charge voltage of the lithium battery and lasts for a first preset time, the lithium battery group is controlled to stop charging, and the sodium battery group is controlled to continue charging; 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 one of the first single cell voltages reaches the lithium battery emptying voltage and lasts for a second preset time, the lithium battery group is controlled to stop discharging, and the sodium battery group is controlled to continue discharging.

2. The control method of the hybrid battery management circuit according to claim 1, characterized in that: 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 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.

3. The control method of the hybrid battery management circuit according to claim 1, characterized in that: 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 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 performed.

4. The control method of the hybrid battery management circuit as claimed in 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 used 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 used to connect the sodium battery pack when being turned on, and disconnect the connection of the sodium battery pack when being turned off; A charge and discharge switch circuit, wherein the charge and discharge switch circuit is connected to the first switch circuit and the second switch circuit respectively, and the charge and discharge switch circuit is also used to connect to an external charging input terminal or a load, and the charge and discharge switch circuit is used to start the charge and discharge of the lithium battery and / or the sodium battery when it is turned on, and stop the charge and discharge of the lithium battery and / or the sodium battery when it is 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 group and the total voltage of the sodium battery group is greater than a preset difference, the second switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 first switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 first switch circuit, the second switch circuit and the charge and discharge switch circuit are controlled to be turned on, until any one of the first monomer voltages reaches the full charge voltage of the lithium battery and lasts for the first preset time, and the first switch circuit is controlled to be turned off.

5. The control method of the hybrid battery management circuit as claimed in claim 4, characterized in that: The step S30 specifically includes: Step S31: 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 first switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 second switch circuit is controlled to be turned on with the charge and discharge switch circuit; 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 first switch circuit, the second switch circuit and the charge and discharge switch circuit are controlled to be turned on, until any one of the first monomer voltages reaches the lithium battery empty voltage and lasts for the second preset time, and the first switch circuit is controlled to be turned off.

6. The control method of the hybrid battery management circuit as claimed in claim 4, characterized in that: The hybrid battery management circuit further includes: 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; a second temperature detection circuit, which is disposed close to the sodium battery pack and is used 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 an external charging input terminal, in response to the charging start instruction, the first temperature detection signal and the second temperature detection signal are acquired, and the first ambient temperature is determined according to the first temperature detection signal, and the second ambient temperature is determined 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 hybrid charging condition is met, and step S21 is executed.

7. The control method of the hybrid battery management circuit as claimed in claim 6, 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, the first temperature detection signal and the second temperature detection signal are acquired, and the first ambient temperature is determined according to the first temperature detection signal, and the second ambient temperature is determined 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.

8. The control method of the hybrid battery management circuit as claimed in claim 5, 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 used to connect to the lithium battery pack when being turned on and limit the discharge current of the lithium battery pack, and to disconnect the lithium battery pack when being turned off; a second current limiting switch circuit, the second current limiting switch circuit being connected to the sodium battery group and the charge and discharge switch circuit respectively, the second current limiting switch circuit being used to connect to the sodium battery group when being turned on and limit the discharge current of the sodium battery group, and to disconnect the connection of the sodium battery group when being turned off; The step S31 comprises: 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 the preset difference, the first current limiting switch circuit is controlled to be turned on with the charge and discharge switch circuit, and after the 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 group and the total voltage of the lithium battery group is greater than the preset difference, the second current limiting switch circuit is controlled to be turned on with the charge and discharge switch circuit, 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 group and the total voltage of the sodium battery group is not greater than the preset difference, the first current limiting switch circuit, the second current limiting switch circuit and the charge and 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, until any one of the first monomer voltages reaches the lithium battery empty voltage and lasts for the second preset time, and the first switch circuit is controlled to be turned off.

9. The control method of the hybrid battery management circuit as claimed in claim 4, 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, wherein the first gating switch circuit is connected to n of the lithium batteries, a controlled end of the first gating switch circuit is connected to an output end of the NOT gate circuit, the first gating switch circuit is used to connect the n lithium batteries when turned on to output a lithium battery voltage detection signal, and 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 used to indicate the voltage of the n first monomers; a second gating switch circuit, wherein the second gating switch circuit is connected to the n sodium batteries, the controlled end of the second gating switch circuit is connected to the voltage detection control signal input end, the second gating switch circuit is used to connect the n sodium batteries when it is turned on to output a sodium battery voltage detection signal, and disconnect the n sodium batteries when it is turned off to stop outputting the sodium battery voltage detection signal; wherein the sodium battery voltage detection signal is used to indicate the voltage of the n second monomers; 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; A second control signal which is inverted with the first control signal is output 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.

10. 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 9 is applied.

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