Battery charging method and circuit, battery device, power utilization device and energy storage device

Abstract

The invention provides a battery charging method and circuit, a battery device, a power utilization device and an energy storage device, and belongs to the technical field of batteries. The method comprises the steps that the batteries are controlled to be in N first charging stages in sequence according to the charge states of the batteries, N is an integer and is larger than or equal to 2, the number of the batteries is two, the two batteries are connected in series, the two batteries are connected to an external charging device after being connected in series, and the batteries are further connected to a first module; the SOC of the battery in the (n + 1) th first charging stage is greater than the SOC of the battery in the nth first charging stage, n is an integer, 1 < = n < = N-1, each first charging stage comprises a constant-current charging stage and a pulse charging stage, the constant-current charging current corresponding to the (n + 1) th first charging stage is less than the constant-current charging current corresponding to the nth first charging stage, and the pulse charging stage is less than the constant-current charging current corresponding to the nth first charging stage. The pulse charging stage comprises the steps of controlling the first module, and enabling the two batteries to discharge mutually. According to the battery charging method, the charging efficiency of the battery can be improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery charging method, circuit, battery device, power device and energy storage device. Background Art

[0002] Energy conservation and emission reduction are the key to sustainable social development. Rechargeable batteries have the characteristics of storing or releasing energy as needed, so they are widely used in various electrical devices or energy storage systems, and are an important part of promoting energy transformation and sustainable development. For the new energy industry, battery technology is an important factor in its development.

[0003] During the charging process, due to the influence of the chemical reaction inside the battery and the movement of current, when the battery SOC (State of Charge) is closer to the full charge state, the chemical reaction inside the battery is close to equilibrium, and the migration of lithium ions becomes difficult. In addition, as the battery SOC increases, the polarization phenomenon of the battery gradually intensifies. This polarization phenomenon may cause the battery energy density to decrease, the charging time to become longer, and the battery charging efficiency to decrease. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the background technology. To this end, one purpose of the present application is to provide a battery charging method, circuit, battery device, power device and energy storage device to solve the problem of low battery charging efficiency in the related technology.

[0005] An embodiment of the first aspect of the present application provides a battery charging method, comprising: controlling the battery to be in N first charging stages in sequence according to the charge state of the battery, N is an integer, N≥2, two batteries are connected in series, and the two batteries are connected to an external charging device after being connected in series, and the battery is also connected to a first module; wherein the SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, n is an integer, 1≤n≤N-1, each first charging stage includes: a constant current charging stage and a pulse charging stage, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage includes: controlling the first module to cause the two batteries to discharge each other.

[0006] In the technical solution of the embodiment of the present application, when the SOC is low, it can withstand a large charging current, so the lower the SOC, the larger the constant current charging current of the corresponding first charging stage, so that the battery can quickly replenish the power. As the SOC gradually increases, the chemical reaction inside the battery tends to be more balanced, and polarization will occur, which reduces the battery's acceptance of the charging current. Based on this, as the SOC gradually increases, the corresponding constant current charging current of the first charging stage is lower, so that it can not only ensure a certain charging speed, but also avoid damage to the battery caused by overcharging to a certain extent. At the same time, each first charging stage includes a pulse charging stage, in which the two batteries discharge each other, so that in the pulse charging stage, the current flowing through the two batteries includes positive pulse current and negative pulse current, which can realize the self-discharge of the battery. During the discharge process, the charge accumulated on the electrode of the battery is rapidly reduced, which can improve the polarization phenomenon of the battery and enhance the battery's acceptance of the charging current, thereby increasing the charging current of the next first charging stage and shortening the charging time of the battery. Furthermore, since the two batteries discharge each other, the two batteries can be depolarized without wasting the existing power of the two batteries, thereby further shortening the battery charging time and improving the battery charging efficiency as a whole.

[0007] In some embodiments, in each first charging stage, the constant current charging stage is controlled to be executed before the pulse charging stage. Thus, when the previous first charging stage is about to switch to the next first charging stage, the battery is placed in the pulse charging stage, so that before the battery switches to the next first charging stage, the battery is depolarized, and the battery's acceptance of the charging current is improved, which is conducive to improving the maximum current that can be used to charge the battery in the next first charging stage, so that in the next first charging stage, a larger constant current can be used to charge the battery, further shortening the charging time and improving the charging efficiency.

[0008] In some embodiments, the method further includes: obtaining the temperature of the battery during the charging process; in response to the battery temperature being greater than or equal to a first threshold, controlling the battery to be in N first charging stages in sequence according to the battery's state of charge; in response to the battery temperature being less than the first threshold, and the battery's SOC being greater than the first SOC threshold, controlling the battery to be in a heating stage, and in the heating stage, using a pulse current to heat the battery. Thus, when the battery temperature is less than the first threshold, the battery's own temperature is relatively low, and at this time, a pulse current is used to heat the battery to increase the battery's temperature. When the battery temperature reaches the first threshold, the activity of the battery's electrode material increases, and the battery's overall charge and discharge performance improves. At this time, the battery is controlled to be in N first charging stages in sequence, which is beneficial to further improve the battery's charging efficiency during each first charging stage.

[0009] In some embodiments, in the first charging stage, the two batteries are respectively the first battery and the second battery. During the mutual discharge between the first battery and the second battery, the charging device is also controlled to charge the first battery and the second battery, and the charging current of the charging device to the first battery and the second battery is less than the discharge current from the first battery to the second battery, and less than the discharge current from the second battery to the first battery. By controlling the charging current of the charging device to the first battery and the second battery to be less than the discharge current from the first battery to the second battery, and less than the discharge current from the second battery to the first battery, during the mutual discharge between the first battery and the second battery, the current flowing through the first battery and the second battery can form a negative pulse current to depolarize the first battery and the second battery. At the same time, since the mutual discharge between the first battery and the second battery is essentially an energy exchange, it can not only achieve the depolarization of the first battery and the second battery, but also will not consume the original power of the first battery and the second battery. On this basis, the charging device charges the first battery and the second battery, which can further shorten the charging time and further improve the charging efficiency.

[0010] In some embodiments, the two batteries are respectively a first battery and a second battery, and the method further includes: obtaining the temperature of the first battery and the second battery during the charging process; in response to the temperature of the first battery and the second battery being greater than or equal to the first threshold, controlling the first battery and the second battery to be in N first charging stages in sequence according to the charge state of the first battery and the second battery; in response to the temperature of any one of the first battery and the second battery being less than the first threshold, and the SOC of the first battery and the second battery being greater than the first SOC threshold, controlling the first battery and the second battery to be in a heating stage, and the heating stage includes: controlling the first module to discharge the first battery and the second battery to each other. By controlling the first module to discharge the first battery and the second battery to each other, the first battery and the second battery exchange energy, realize self-heating during the energy exchange process, and keep the power balance of the first battery and the second battery at the same time, without wasting the existing power of the first battery and the second battery, which is conducive to shortening the charging time of the first battery and the second battery and improving the charging efficiency.

[0011] In some embodiments, the heating stage further includes: during the period when the first battery and the second battery discharge each other, controlling the charging device to charge the first battery and the second battery, and the charging current of the charging device to the first battery and the second battery is less than the discharge current of the first battery to the second battery, and less than the discharge current of the second battery to the first battery. In this way, the battery can be heated, and the first battery and the second battery can be charged by the charging device during the heating stage, so that the battery is heated and charged at the same time, further improving the charging efficiency.

[0012] In some embodiments, the heating stage further includes: in response to the temperature of either the first battery or the second battery being less than the first threshold and greater than or equal to the second threshold, during the mutual discharge of the first battery and the second battery, controlling the charging device to charge the first battery and the second battery based on the first current, the second threshold being less than the first threshold; in response to the temperature of either the first battery or the second battery being less than the second threshold, during the mutual discharge of the first battery and the second battery, controlling the charging device to charge the first battery and the second battery based on the second current, wherein the first current is greater than the second current, and the first current is less than the discharge current of the first battery to the second battery, and less than the discharge current of the second battery to the first battery. When the battery temperature is too low, the battery's acceptance of the charging current is too low. In order to reduce damage to the battery, in response to the temperature of either the first battery or the second battery being less than the second threshold, the first battery and the second battery are charged with a relatively small second current. When the battery temperature gradually rises to the first threshold, the battery's acceptance of the charging current is improved. Based on this, in response to the temperature of either the first battery or the second battery being greater than or equal to the second threshold and less than the first threshold, the first battery and the second battery are charged with a relatively large first current to improve the charging efficiency.

[0013] In some embodiments, when the two batteries are respectively a first battery and a second battery, the first module includes a switch circuit and a first energy storage circuit, the negative electrode of the first battery is connected to the positive electrode of the second battery, the positive electrode of the first battery is connected to the first end of the switch circuit, the negative electrode of the second battery is connected to the second end of the switch circuit, the switch circuit is also connected to the first end of the first energy storage circuit, the second end of the first energy storage circuit is connected to the midpoint of the first battery and the second battery, and controlling the first module to make the first battery and the second battery discharge each other includes: performing at least one step of the first battery discharging to the first energy storage circuit and the first energy storage circuit discharging to the second battery through the switch circuit, so that the first battery discharges to the second battery, and performing at least one step of the second battery discharging to the first energy storage circuit and the first energy storage circuit discharging to the first battery through the switch circuit, so that the second battery discharges to the first battery. The first energy storage circuit plays the role of temporarily storing energy. Through the first energy storage circuit, the discharge speed of the first battery and the second battery can be controlled so that the discharge amount of the first battery and the second battery each time is not too much, reducing the probability of the first battery and the second battery being out of power. Furthermore, in the pulse charging stage and the heating stage of the first charging stage, when the control device charges the first battery and the second battery, since the first energy storage circuit plays the role of temporarily storing energy, the current flowing through the first battery during the discharge of the first battery to the first energy storage circuit is negative, and the current flowing through the first battery during the discharge of the first energy storage circuit to the second battery is positive, thereby forming a pulse current in the first battery, and similarly, forming a pulse current in the second battery, thereby respectively achieving depolarization and heating of the first battery and the second battery.

[0014] In some embodiments, the two ends of the first battery and the second battery connected in series are further connected in parallel with a second energy storage circuit, and the method further includes: through a switch circuit, the first battery is discharged to the first energy storage circuit and the second energy storage circuit is discharged to the second battery at the same time, and the first energy storage circuit is discharged to the second battery and the first battery is discharged to the second energy storage circuit at the same time; and / or, through a switch circuit, the second battery is discharged to the first energy storage circuit and the second energy storage circuit is discharged to the first battery at the same time, and the first energy storage circuit is discharged to the first battery and the second battery is discharged to the second energy storage circuit at the same time. Thus, during the period when the first battery is discharged to the second battery and the period when the second battery is discharged to the first battery, current continues to flow through the first battery and the second battery, which is conducive to maintaining the stability of the circuit.

[0015] In some embodiments, the switch circuit includes: a bridge arm, including an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm is connected to the positive electrode of the first battery, the lower bridge arm is connected to the negative electrode of the second battery, and the first end of the first energy storage circuit is connected between the upper bridge arm and the lower bridge arm; through the switch circuit, the step of performing at least one discharge of the first battery to the first energy storage circuit and the first energy storage circuit to the second battery includes: alternately performing the first step and the second step in sequence, and through the switch circuit, the step of performing at least one discharge of the second battery to the first energy storage circuit and the first energy storage circuit to the first battery includes: alternately performing the second step and the first step in sequence; wherein the first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; the second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off. Thus, by controlling the alternating conduction of the upper bridge arm and the lower bridge arm, the mutual charging and discharging of the first battery and the second battery can be realized, the operation is simple, and the battery charging control method is simplified.

[0016] The embodiment of the second aspect of the present application provides a battery charging control circuit, the number of batteries is two, the two batteries are connected in series, and the two batteries are connected to an external charging device after being connected in series, the charging control circuit includes: a first module, connected to the battery; a controller, connected to the charging device in communication, the controller is configured to: control the charging device to charge the battery, and control the battery to be in N first charging stages in sequence according to the state of charge of the battery, N is an integer greater than 1: wherein the SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, n is an integer, 1≤n≤N-1, each first charging stage includes: a constant current charging stage and a pulse charging stage, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage includes: controlling the first module to discharge the two batteries to each other. As the SOC gradually increases, the corresponding constant current charging current of the first charging stage is lower, so that a certain charging speed can be guaranteed and overcharging can be avoided to a certain extent. Damage to the battery. At the same time, each first charging stage includes a pulse charging stage, in which the two batteries discharge each other, so that in the pulse charging stage, the current flowing through the two batteries includes positive pulse current and negative pulse current to achieve self-discharge of the battery. During the discharge process, the charge accumulated on the electrodes of the battery decreases rapidly, which can improve the polarization phenomenon of the battery and enhance the battery's acceptance of the charging current, thereby increasing the charging current of each first charging stage compared to the case without the pulse charging stage, further shortening the battery's charging time and improving the battery's charging efficiency. In addition, since the two batteries discharge each other, the depolarization of the two batteries can be achieved without consuming the existing power of the two batteries, thereby further shortening the battery's charging time and improving the battery's charging efficiency as a whole.

[0017] In some embodiments, the controller is further configured to: control the constant current charging stage to be executed before the pulse charging stage. Thus, when the previous first charging stage is about to switch to the next first charging stage, the battery is placed in the pulse charging stage, so that before the battery switches to the next first charging stage, the battery is depolarized, and the battery's acceptance of the charging current is improved, which is conducive to improving the maximum current that can be used to charge the battery in the next first charging stage, so that in the next first charging stage, a larger constant current can be used to charge the battery, further shortening the charging time and improving the charging efficiency.

[0018] In some embodiments, the controller is further configured to: obtain the temperature of the battery during the charging process; in response to the battery temperature being greater than or equal to a first threshold, control the battery to be in N first charging stages in sequence according to the battery's state of charge; in response to the battery temperature being less than the first threshold, and the battery's SOC being greater than the first SOC threshold, control the battery to be in a heating stage, and in the heating stage, use a pulse current to heat the battery. When the battery temperature is less than the first threshold, the battery's own temperature is low, and at this time, a pulse current is used to heat the battery to increase the battery's temperature. When the battery temperature reaches the first threshold, the activity of the battery's electrode material increases, and the battery's overall charge and discharge performance improves. At this time, the battery is controlled to be in N first charging stages in sequence, which is conducive to further improving the battery's charging efficiency during each first charging stage.

[0019] In some embodiments, the controller is further configured as follows: the two batteries are respectively a first battery and a second battery, and in the first charging stage, during the period when the first battery and the second battery discharge each other, the charging device is controlled to charge the first battery and the second battery, and the charging current of the charging device to the first battery and the second battery is less than the discharge current from the first battery to the second battery, and less than the discharge current from the second battery to the first battery. As a result, during the period when the first battery and the second battery discharge each other, the current flowing through the first battery and the second battery can form a negative pulse current to depolarize the first battery and the second battery. At the same time, since the mutual discharge of the first battery and the second battery is essentially an energy exchange, it can not only achieve the depolarization of the first battery and the second battery, but also will not consume the energy of the first battery and the second battery. On this basis, the charging device charges the first battery and the second battery, which can further shorten the charging time and further improve the charging efficiency.

[0020] In some embodiments, the two batteries are respectively a first battery and a second battery, and the controller is further configured to: obtain the temperature of the first battery and the second battery during the charging process; in response to the temperature of the first battery and the second battery being greater than or equal to the first threshold, control the first battery and the second battery to be in N first charging stages in sequence according to the charge state of the first battery and the second battery; in response to the temperature of either the first battery and the second battery being less than the first threshold, and the SOC of the first battery and the second battery being greater than the first SOC threshold, control the first battery and the second battery to be in the heating stage, and the heating stage includes: controlling the first module to make the first battery and the second battery discharge each other. By controlling the first module to make the first battery and the second battery discharge each other, the first battery and the second battery exchange energy, realize self-heating during the energy exchange process, and keep the power balance of the first battery and the second battery at the same time, without wasting the existing power of the first battery and the second battery, which is conducive to shortening the charging time of the first battery and the second battery and improving the charging efficiency.

[0021] In some embodiments, the controller is further configured to: during the heating stage, while the first battery and the second battery are discharging from each other, control the charging device to charge the first battery and the second battery, and the charging current of the charging device to the first battery and the second battery is less than the discharge current of the first battery to the second battery, and less than the discharge current of the second battery to the first battery. In this way, the battery can be heated, and the first battery and the second battery can be charged by the charging device during the heating stage, so that the battery is heated and charged at the same time, further improving the charging efficiency.

[0022] In some embodiments, the controller is further configured to: in the heating stage, in response to the temperature of either the first battery and the second battery being less than the first threshold and greater than or equal to the second threshold, during the mutual discharge of the first battery and the second battery, control the charging device to charge the first battery and the second battery based on the first current, and the second threshold is less than the first threshold; in response to the temperature of either the first battery and the second battery being less than the second threshold, during the mutual discharge of the first battery and the second battery, control the charging device to charge the first battery and the second battery based on the second current, wherein the first current is greater than the second current, and the first current is less than the discharge current of the first battery to the second battery, and less than the discharge current of the second battery to the first battery. In the case where the temperature of either the first battery and the second battery is less than the second threshold, a relatively small second current is used to charge the first battery and the second battery to reduce damage to the battery. When the temperature of the battery gradually rises to the first threshold, in response to the temperature of either the first battery and the second battery being greater than or equal to the second threshold and less than the first threshold, a relatively large first current is used to charge the first battery and the second battery to improve the charging efficiency.

[0023] In some embodiments, when the two batteries are the first battery and the second battery, the negative electrode of the first battery is connected to the positive electrode of the second battery, and the first module includes: a switch circuit, the positive electrode of the first battery is connected to the first end of the switch circuit, and the negative electrode of the second battery is connected to the second end of the switch circuit; a first energy storage circuit, the first end of the first energy storage circuit is connected to the switch circuit, and the second end is connected to the midpoint of the first battery and the second battery; the controller is configured to: through the switch circuit, perform at least one step of the first battery discharging to the first energy storage circuit and the first energy storage circuit discharging to the second battery, so that the first battery discharges to the second battery, and, through the switch circuit, perform at least one step of the second battery discharging to the first energy storage circuit and the first energy storage circuit discharging to the first battery, so that the second battery discharges to the first battery. In this way, a pulse current can be formed in the first battery and the second battery, and then the first battery and the second battery can be depolarized and heated respectively.

[0024] In some embodiments, the battery charging control circuit further includes: a second energy storage circuit connected in parallel with the first battery and the second battery connected in series; the controller is further configured to: through a switch circuit, simultaneously execute the discharge of the first battery to the first energy storage circuit and the discharge of the second energy storage circuit to the second battery, and simultaneously execute the discharge of the first energy storage circuit to the second battery and the discharge of the first battery to the second energy storage circuit; and / or, through a switch circuit, simultaneously execute the discharge of the second battery to the first energy storage circuit and the discharge of the second energy storage circuit to the first battery, and simultaneously execute the discharge of the first energy storage circuit to the first battery and the discharge of the second battery to the second energy storage circuit. By setting the second energy storage circuit, during the discharge of the first battery to the second battery and the discharge of the second battery to the first battery, current continues to flow through the first battery and the second battery, which is conducive to maintaining the stability of the circuit.

[0025] In some embodiments, the first energy storage circuit includes at least one inductor, and the second energy storage circuit includes a capacitor. The inductor can store a large amount of electricity, which can improve the energy transfer efficiency from the first battery to the second battery, thereby improving the heating efficiency of the battery. Compared with the inductor, the capacitor is smaller in size, and the capacitor can achieve rapid charging and discharging, so that during the entire period when the first battery and the second battery discharge each other, there is always current flowing through the first battery and the second battery, which is conducive to maintaining the stability of the current flowing through the first battery and the second battery, and at the same time, keeping the volume of the circuit for heating the battery small, saving costs.

[0026] In some embodiments, the switch circuit includes: a bridge arm, including an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm is connected to the positive electrode of the first battery, the lower bridge arm is connected to the negative electrode of the second battery, and the first end of the first energy storage circuit is connected between the upper bridge arm and the lower bridge arm; the controller is configured to: alternately perform the first step and the second step in sequence to make the first battery discharge to the second battery, and alternately perform the second step and the first step in sequence to make the second battery discharge to the first battery; wherein the first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; the second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off. By controlling the alternating conduction of the upper bridge arm and the lower bridge arm, the mutual charging and discharging of the first battery and the second battery can be realized, the operation is simple, and the battery charging control circuit is simplified.

[0027] An embodiment of a third aspect of the present application provides a battery device, which includes the battery charging control circuit in the above embodiment.

[0028] An embodiment of the fourth aspect of the present application provides an electrical device, which includes the battery device in the above embodiment, and the battery device is used to provide electrical energy.

[0029] An embodiment of the fifth aspect of the present application provides an energy storage device, which includes the battery device in the above embodiment, and the battery device is used to store electrical energy.

[0030] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0032] Figure 1 This is one of the current waveform schematic diagrams for controlling the battery to be in N first charging stages in sequence in the battery charging method of some embodiments of the present application; Figure 2 This is a second current waveform schematic diagram of controlling a battery to be in N first charging stages in sequence in a battery charging method in some embodiments of the present application; Figure 3 This is one of the functional block diagrams of the battery charging control circuit in some embodiments of the present application; Figure 4 One of the flow charts of the battery charging method according to some embodiments of the present application; Figure 5 This is one of the current waveform schematic diagrams for controlling a battery to be in a heating stage in a battery charging method in some embodiments of the present application; Figure 6 This is a second schematic diagram of a current waveform for controlling a battery to be in a heating stage in a battery charging method according to some embodiments of the present application; Figure 7 This is a second flowchart of a battery charging method according to some embodiments of the present application; Figure 8 This is a third flowchart of a battery charging method according to some embodiments of the present application; Fig. 9 This is the second functional block diagram of the battery charging control circuit of some embodiments of the present application; Fig.10 This is the third functional block diagram of the battery charging control circuit of some embodiments of the present application; Fig.11 A schematic diagram of a current path corresponding to executing the first step in the battery charging method in some embodiments of the present application to discharge the first battery into the first energy storage circuit; Fig.12 A schematic diagram of a current path corresponding to executing the second step in the battery charging method of some embodiments of the present application to enable the first energy storage circuit to discharge to the second battery; Fig.13 A schematic diagram of a current path corresponding to executing the second step in the battery charging method of some embodiments of the present application to discharge the second battery into the first energy storage circuit; Fig.14 A schematic diagram of a current path corresponding to executing the first step in the battery charging method of some embodiments of the present application to enable the first energy storage circuit to discharge to the first battery.

[0033] Description of reference numerals: A switch circuit 1021, a first energy storage circuit 1022, and a second energy storage circuit 1023; Charging device 101, first module 102; A first battery 11, a second battery 12; Bridge arm 20, current sensor 23, first connector 24, second connector 25; First freewheeling diode D1, second freewheeling diode D2, first switch K1, second switch K2, third switch K3, first inductor L1, second inductor L2, first resistor R1, constant current charging stage S1, pulse charging stage S2, upper bridge arm switch tube V1, lower bridge arm switch tube V2, fourth switch V3. DETAILED DESCRIPTION

[0034] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0036] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0037] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0039] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0040] During the charging process of the battery, due to the influence of the chemical reaction inside the battery and the movement of current, the closer the battery SOC is to the full charge state, the closer the chemical reaction inside the battery is to equilibrium, and the migration of lithium ions becomes difficult. In addition, as the battery SOC increases, the polarization phenomenon of the battery gradually intensifies. One of the reasons for the polarization of the battery is that when a large current flows through the electrode, charges will accumulate on the positive and negative electrodes of the battery, causing the potential of the electrode to deviate from the equilibrium potential, resulting in a difference between the actual potential of the battery and the equilibrium potential. This difference leads to a polarization voltage, and the greater the charging current, the more charges accumulate on the electrodes of the battery, and the greater the polarization voltage. The presence of polarization voltage will increase the resistance of the battery, making the current flowing through the battery smaller, thereby reducing the charging efficiency of the battery.

[0041] Based on the above considerations, a battery charging method is designed, comprising: controlling the battery to be in N first charging stages in sequence according to the state of charge of the battery, N is an integer, N≥2, the number of batteries is two, the two batteries are connected in series, and the two batteries are connected to an external charging device after being connected in series, and the battery is also connected to a first module; wherein, the SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, n is an integer, 1≤n≤N-1, each first charging stage comprises: a constant current charging stage and a pulse charging stage, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage comprises: controlling the first module to cause the two batteries to discharge each other.

[0042] When the SOC is low, the corresponding constant current charging current of the first charging stage is large, so that the battery can quickly replenish the power. As the SOC gradually increases, the corresponding constant current charging current of the first charging stage is lower, so that a certain charging speed can be guaranteed and overcharging can be avoided to a certain extent. Damage to the battery. At the same time, each first charging stage includes a pulse charging stage, in which the two batteries discharge each other, so that in the pulse charging stage, the current flowing through the two batteries includes positive pulse current and negative pulse current, which can realize the self-discharge of the battery. During the discharge process, the charge accumulated on the electrode of the battery is rapidly reduced, which can improve the polarization phenomenon of the battery and enhance the battery's acceptance of the charging current, thereby increasing the charging current of the next first charging stage, shortening the battery's charging time, and improving the battery's charging efficiency. In addition, since the two batteries discharge each other, it is possible to achieve depolarization of the two batteries without consuming the existing power of the two batteries, thereby further shortening the battery's charging time and improving the battery's charging efficiency as a whole.

[0043] The battery charging control method disclosed in the embodiment of the present application can be used, but is not limited to, for charging batteries in electrical devices or energy storage devices such as vehicles, ships or aircraft.

[0044] The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0045] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0046] The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended range vehicle, etc. A battery is arranged inside the vehicle, and the battery may be arranged at the bottom, head or tail of the vehicle. The battery may be used to power the vehicle, for example, the battery may be used as an operating power source for the vehicle.

[0047] In some embodiments of the present application, the battery can be used not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0048] refer to Figures 1 to 3 , an embodiment of the present application provides a battery charging method, comprising: controlling the battery to be in N first charging stages in sequence according to the state of charge of the battery, N is an integer, N≥2, the number of batteries is two, the two batteries are connected in series, and the two batteries are connected to an external charging device 101 after being connected in series, and the two batteries are also connected to a first module 102; wherein, the SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, n is an integer, 1≤n≤N-1, each first charging stage includes: a constant current charging stage S1 and a pulse charging stage S2, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage S2 includes: controlling the first module 102 to cause the two batteries to discharge each other.

[0049] SOC refers to the ratio of the remaining power of a battery under certain conditions to the rated capacity of the battery. The number N is related to the type of battery. Different types of batteries have different charging performances. For large-capacity batteries, the number N will be greater, and for small-capacity batteries, the number N will be relatively small. In order to determine the optimal number of N, multiple rounds of charge and discharge tests can be carried out for different types of batteries in advance, and the charging time of the battery under different N values ​​can be collected and analyzed, and the N value can be determined based on the charging time.

[0050] Exemplarily, the number of N can be 4, corresponding to the first first charging stage when the SOC is 0%~30%, corresponding to the second first charging stage when the SOC is 30%~60%, corresponding to the third first charging stage when the SOC is 60%~80%, and corresponding to the fourth first charging stage when the SOC is 80%~100%. From the first first charging stage to the fourth first charging stage, the constant current charging current used gradually decreases. Constant current charging current means that the charging current remains consistent or substantially consistent.

[0051] It is understandable that in some embodiments, in response to the SOC of the battery reaching the first preset value, the battery can be controlled to be in N first charging stages in sequence. The first preset value can be 10%, 20% or 30%, etc. When the battery SOC is less than the first preset value, the chemical reaction inside the battery is rapid, a large amount of charge is injected into the battery, and the polarization degree of the battery is low. At this time, constant current charging can be used to quickly replenish the battery.

[0052] In some embodiments, in response to the SOC of the battery reaching a second preset value, the battery can be charged with a constant current. That is, in response to the SOC of the battery reaching the second preset value, the step of controlling the battery to be in N first charging stages in sequence is terminated. The second preset value can be 90%, 95% or 98%. In this way, when the battery is about to be fully charged, the battery can be accurately charged with a constant current so that the battery can reach a fully charged state.

[0053] That is to say, the N first charging stages may run through the entire charging process of the battery, or the battery may be placed in the N first charging stages in sequence only during a portion of the charging process of the battery.

[0054] When N≥3, the change amplitude of the constant current charging current corresponding to each two consecutive first charging stages may be different. For example, when the SOC is small, the decrease amplitude of the constant current charging current corresponding to the next first charging stage compared to the previous first charging stage may be smaller, and when the SOC is large, the decrease amplitude of the constant current charging current corresponding to the next first charging stage compared to the previous first charging stage may be larger. The current size used in each first charging stage may vary according to different battery types. In order to determine the optimal constant current charging current, multiple rounds of charge and discharge tests may be carried out in advance for different types of batteries, and the charging time of the battery under different constant current charging currents may be collected and analyzed, and the constant current charging current value may be determined according to the charging time.

[0055] The charging device may include but is not limited to a charging pile. In the constant current charging stage, the charging device performs constant current charging on the first battery and the second battery, so that the batteries are in the constant current charging stage. The charging device may change the output current size based on the charge state of the battery, so that the batteries are in the constant current charging stages of N first charging stages respectively.

[0056] The two batteries can be respectively recorded as a first battery 11 and a second battery 12, and the first battery 11 and the second battery 12 connected in series are connected to a charging device 101, so that the charging device 101 charges the first battery 11 and the second battery 12 connected in series. Exemplarily, the negative electrode of the first battery 11 is connected to the positive electrode of the second battery 12, the positive electrode of the first battery 11 is connected to the positive electrode of the charging device 101, and the negative electrode of the second battery 12 is connected to the negative electrode of the charging device 101, so that the charging current output by the positive electrode of the charging device 101 flows through the first battery 11 and the second battery 12 in sequence to charge the first battery 11 and the second battery 12 simultaneously.

[0057] The mutual discharge between the first battery 11 and the second battery 12 means that after the first battery 11 discharges to the second battery 12, the second battery 12 discharges to the first battery 11. During the discharge of the first battery 11 to the second battery 12, the current flowing through the first battery 11 is negative, and the current flowing through the second battery 12 is positive. During the discharge of the second battery 12 to the first battery 11, the current flowing through the first battery 11 is positive, and the current flowing through the second battery 12 is negative. That is, the current flowing through the first battery 11 alternates between positive and negative to form a pulse current, and the current flowing through the second battery 12 alternates between positive and negative to form a pulse current. In other words, in the pulse charging stage S2, the current flowing through the first battery 11 and the second battery 12 both include positive pulse current and negative pulse current. The positive pulse current refers to a current with the same charging direction as the constant current charging current, that is, the direction of the positive pulse current is that the current flows from the positive pole of the battery to the negative pole of the battery. Negative pulse current refers to a current in the opposite direction to the constant current charging current, that is, the direction of the negative pulse current is from the negative electrode of the battery to the positive electrode of the battery, so that the battery is in a short discharge state. During the discharge process, the battery can quickly reduce the charge accumulated on the electrode and improve the polarization phenomenon. The embodiment of the present application controls the mutual discharge of the first battery 11 and the second battery 12 to achieve the passage of pulse current through the first battery 11 and the second battery 12. In this way, even if the charging device does not have the function of outputting pulse current, the depolarization of the first battery 11 and the second battery 12 can be achieved, reducing the dependence and requirements on the charging device and saving equipment costs.

[0058] In some embodiments, the number of positive pulse currents may be equal to the number of negative pulse currents, and the positive pulse currents and the negative pulse currents may be alternated. Exemplarily, in the case of including a plurality of positive pulse currents and negative pulse currents, the negative pulse currents and the positive pulse currents are alternated in sequence, so that the positive pulse current can compensate for the amount of electricity consumed by the battery during discharge without consuming the existing amount of electricity in the battery.

[0059] It can be understood that, under the condition of the same current magnitude, the rate of charge released during battery discharge is greater than the rate of charge accumulation during battery charging. That is, during the period when the negative pulse current is input into the battery, the rate of charge release in the battery is greater than the rate of charge accumulation in the battery during the period when the positive pulse current is input, that is, applying a positive pulse current to the battery will not cause the charge released during the battery discharge to accumulate again, thereby effectively depolarizing the battery without consuming the existing power of the battery.

[0060] like Figure 1 As shown, in some embodiments, in the pulse charging stage S2, the number of positive pulse currents may be equal to the number of negative pulse currents. The absolute value of the positive pulse current may be equal to the absolute value of the negative pulse current.

[0061] like Figure 2 As shown, in other embodiments, in the pulse charging stage S2, the number of positive pulse currents may also be greater than the number of negative pulse currents. Exemplarily, the pulse charging stage S2 can be divided into a continuous first sub-stage and a second sub-stage, in which the negative pulse current and the positive pulse current are output alternately, and in the second sub-stage, only a plurality of positive pulse currents are included, and the plurality of positive pulse currents are output continuously, and the positive pulse current in the second sub-stage is greater than the constant current charging current of the first charging stage in which it is located. The first sub-stage may be executed before the second sub-stage, or after the second sub-stage.

[0062] In some embodiments, the first battery 11 and the second battery 12 may discharge each other once or multiple times, for example, five times.

[0063] In some embodiments, the mutual discharge of the first battery 11 and the second battery 12 may include: repeatedly and alternately performing a step of the first battery 11 discharging the second battery 12 and a step of the second battery 12 discharging the first battery 11 for a plurality of times.

[0064] In some other embodiments, the mutual discharge of the first battery 11 and the second battery 12 may also include: after the step of charging the second battery 12 with the first battery 11 is executed multiple times in succession, the step of charging the first battery 11 with the second battery 12 is executed multiple times in succession.

[0065] In some embodiments, the first module 102 can form a loop with the first battery 11 and the second battery 12 respectively. The first module 102 can include at least a capacitor, an inductor, and other components with charging and discharging functions. Capacitors or inductors both have the function of charging and discharging. When one of the first battery 11 or the second battery 12 forms a loop with the first module 102, it can temporarily store the electric energy released by one of the first battery 11 or the second battery 12. After the other of the first battery 11 and the second battery 12 forms a loop with the first module 102, the capacitor or inductor releases energy to the other of the first battery 11 and the second battery 12, thereby realizing the discharge of the first battery 11 to the second battery 12, or the discharge of the second battery 12 to the first battery 11.

[0066] In some embodiments, the pulse charging stage S2 may be performed at the end of each first charging stage, that is, the constant current charging stage S1 may be performed before the pulse charging stage S2.

[0067] In some other embodiments, the pulse charging stage S2 may also be performed in the middle of each first charging stage, that is, each first charging stage may include two constant current charging stages S1, and the two constant current charging stages S1 are performed before and after the pulse charging stage S2 respectively.

[0068] In other embodiments, for the first first charging stage, since the polarization degree is low at the beginning of charging, the pulse charging stage S2 can be set to be performed at the end of the first charging stage. For the second and subsequent first charging stages, the pulse charging stage S2 can be immediately entered at the beginning of the first charging stage, that is, for the second and subsequent first charging stages, the pulse charging stage S2 can be executed before the constant current charging stage S1. In this way, for the second and subsequent first charging stages, at the beginning of each first charging stage, the battery is depolarized to improve the polarization of the battery, so that the battery's acceptance of the charging current is improved, thereby increasing the charging current of the subsequent constant current charging stage S1.

[0069] Exemplarily, the charging device may be connected to a BMS (Battery Management System). The BMS may send a charging message to the charging device, and the charging device charges the battery based on the charging message sent by the BMS. The message data corresponding to the N first charging stages may be pre-stored in the BMS, and the message data may include data such as the voltage, current, temperature, and SOC for charging the battery. The BMS may detect the SOC of the battery, and when the SOC of the battery reaches the condition for entering the next first charging stage, it may send a message to the charging device to enter the next first charging stage. The charging device adjusts the current output to the battery based on the charging message sent by the BMS, so that the battery is in the constant current charging stage of the N first charging stages respectively.

[0070] Due to the complexity of the battery structure itself, the battery state of charge cannot be obtained by direct measurement in some cases. The battery SOC can be obtained by using relevant characteristic curves or calculation formulas based on relevant parameters such as the battery's internal resistance, temperature, and current. The method for obtaining the battery SOC is a technology well known to those skilled in the art and will not be repeated here.

[0071] In the above technical solution, when the SOC is low, it can withstand a larger charging current, so the lower the SOC, the larger the corresponding constant current charging current of the first charging stage, so that the battery can quickly replenish the power. As the SOC gradually increases, the chemical reaction inside the battery tends to be more balanced, and polarization will occur, which reduces the battery's acceptance of the charging current. Based on this, in the above technical solution, as the SOC gradually increases, the corresponding constant current charging current of the first charging stage is lower, so that it can not only ensure a certain charging speed, but also avoid damage to the battery caused by overcharging to a certain extent. At the same time, each first charging stage includes a pulse charging stage S2, and the two batteries in the pulse charging stage S2 discharge each other, so that in the pulse charging stage S2, the current flowing through the two batteries includes positive pulse current and negative pulse current to achieve self-discharge of the battery. During the discharge process, the charge accumulated on the electrode of the battery is rapidly reduced, which can improve the polarization phenomenon of the battery and enhance the battery's acceptance of the charging current, so that compared with the case without the pulse charging stage S2, the charging current of each first charging stage is increased, further shortening the charging time of the battery and improving the charging efficiency of the battery. Furthermore, since the two batteries discharge each other, the two batteries can be depolarized without wasting the existing power of the two batteries, thereby further shortening the battery charging time and improving the battery charging efficiency as a whole.

[0072] According to some embodiments of the present application, in each first charging stage, the constant current charging stage S1 is controlled to be executed before the pulse charging stage S2.

[0073] That is, before switching to the next first charging stage, the battery is controlled to be in the pulse charging stage S2, and after the pulse charging stage S2 ends, it enters the constant current charging stage S1 of the next first charging stage.

[0074] In the above technical solution, it is possible to put the battery in the pulse charging stage S2 when the previous first charging stage is about to switch to the next first charging stage, so that before the battery switches to the next first charging stage, the battery is depolarized to improve the battery's ability to accept the charging current, which is beneficial to improve the maximum current that can charge the battery in the next first charging stage, and then in the next first charging stage, a larger constant current charging current can be used to charge the battery, further shortening the charging time and improving the charging efficiency.

[0075] refer to Figure 4 as well as Figure 5 According to some embodiments of the present application, the method further includes: Step 110, obtaining the temperature of the battery during the charging process; Step 120, in response to the temperature of the battery being greater than or equal to a first threshold, controlling the battery to be in N first charging stages in sequence according to the state of charge of the battery; Step 130 , in response to the temperature of the battery being less than a first threshold value and the SOC of the battery being greater than the first SOC threshold value, controlling the battery to be in a heating stage, in which a pulse current is used to heat the battery.

[0076] In step 110, a temperature sensor may be used to obtain the temperature of the battery. In some embodiments, the temperature sensor is in communication with the BMS, and a controller in the BMS may receive temperature information detected by the temperature sensor.

[0077] In step 120, the first threshold is a temperature value set in advance. When the temperature is less than the first threshold, it is difficult for the battery to be charged. For example, the first threshold may be minus 10°C. In response to the temperature of the battery being greater than or equal to the first threshold, the BMS may send a message to the charging device to control the battery to be in N first charging stages in sequence.

[0078] In some embodiments, the BMS may also send a message to the charging device to control the battery to be in N first charging stages in sequence in response to the SOC of the battery being greater than a first preset value and the temperature being greater than or equal to a first threshold.

[0079] In some embodiments, in step 130, in response to the temperature of the battery being less than a first threshold and the SOC of the battery being greater than the first SOC threshold, the BMS sends a message to the charging device to heat the battery, so that the charging device uses a pulse current to heat the battery. The first SOC threshold may be the SOC value corresponding to undervoltage of the battery. For example, the first SOC value may be 20%. When the battery SOC drops below 20%, undervoltage is likely to occur. If the battery is discharged at this time, it will cause damage to the battery.

[0080] like Figure 5 As shown, the pulse current used to heat the battery includes a positive pulse current and a negative pulse current, and the positive pulse current and the negative pulse current can be performed alternately, so that the battery is alternately charged and discharged to achieve self-heating.

[0081] It is worth noting that if during the execution of step 120, the temperature sensor detects that the battery temperature is less than the first threshold and the battery SOC is greater than the first SOC threshold, step 130 is executed. When it is detected that the battery temperature reaches the first threshold, step 120 is executed again.

[0082] In the above technical solution, when the battery temperature is less than the first threshold, the battery temperature itself is low, and a pulse current is used to heat the battery to increase the battery temperature. When the battery temperature reaches the first threshold, the activity of the battery electrode material increases, and the overall charge and discharge performance of the battery is improved. At this time, the battery is controlled to be in N first charging stages in sequence, which is conducive to further improving the charging efficiency of the battery during each first charging stage.

[0083] refer to Figure 6 According to some embodiments of the present application, in the first charging stage, during the period when the first battery 11 and the second battery 12 discharge each other, the charging device 101 is also controlled to charge the first battery 11 and the second battery 12, and the charging current of the charging device 101 to the first battery 11 and the second battery 12 is smaller than the discharge current of the first battery 11 to the second battery 12, and smaller than the discharge current of the second battery 12 to the first battery 11.

[0084] Figure 6 The single-dotted line in the figure represents the current waveform of the charging device charging the first battery and the second battery during the heating stage, and the double-dotted line can represent the current waveform of the first battery discharging to the second battery during the heating stage, and can also represent the current waveform of the second battery discharging to the first battery during the heating stage.

[0085] During the discharge of the first battery 11 to the second battery 12, the charging current of the charging device 101 to the first battery 11 is less than the discharge current of the first battery 11 to the second battery 12, so that the first battery 11 is in a discharge state as a whole, thereby having a good depolarization effect on the first battery 11. During the discharge of the second battery 12 to the first battery 11, the charging current of the charging device 101 to the second battery 12 is less than the discharge current of the second battery 12 to the first battery 11, so that the second battery 12 is in a discharge state as a whole, thereby having a good depolarization effect on the second battery 12.

[0086] In some embodiments, during the mutual discharge between the first battery 11 and the second battery 12 , the charging current of the charging device 101 for the first battery 11 and the second battery 12 may be equal to the constant current charging current used in the constant current charging stage S1 .

[0087] In the above technical solution, by controlling the charging current of the charging device 101 to be smaller than the discharge current of the first battery 11 to the second battery 12, and smaller than the discharge current of the second battery 12 to the first battery 11, during the mutual discharge of the first battery 11 and the second battery 12, the current flowing through the first battery 11 and the second battery 12 can form a negative pulse current to depolarize the first battery 11 and the second battery 12. At the same time, since the mutual discharge of the first battery 11 and the second battery 12 is essentially an energy exchange, not only can the depolarization of the first battery 11 and the second battery 12 be achieved, but also the original power of the first battery 11 and the second battery 12 will not be consumed. On this basis, the charging device 101 charges the first battery 11 and the second battery 12, which can further shorten the charging time and further improve the charging efficiency.

[0088] refer to Figure 7 According to some embodiments of the present application, the method further includes: Step 210, obtaining the temperature of the first battery 11 and the second battery 12 during the charging process; Step 220, in response to the temperature of the first battery 11 and the second battery 12 being greater than or equal to the first threshold, controlling the first battery 11 and the second battery 12 to be in N first charging stages in sequence according to the charge states of the first battery 11 and the second battery 12; Step 230, in response to the temperature of either the first battery 11 or the second battery 12 being less than the first threshold, and the SOC of the first battery 11 and the second battery 12 being greater than the first SOC threshold, controlling the first battery 11 and the second battery 12 to be in a heating stage, the heating stage comprising: The first module 102 is controlled to make the first battery 11 and the second battery 12 discharge each other.

[0089] Step 210 may be the same as step 110 and will not be described in detail herein.

[0090] In step 220, since the first battery 11 and the second battery 12 are connected in series, the currents passing through the first battery 11 and the second battery 12 are the same, and the charge changes experienced by the first battery 11 and the second battery 12 are consistent during the same charge and discharge time. When the first battery 11 and the second battery 12 have the same capacity, the SOCs of the first battery 11 and the second battery 12 are consistent. Based on this, the first battery 11 and the second battery 12 can be simultaneously controlled to be in N first charging stages in sequence based on the SOC of either the first battery 11 or the second battery 12.

[0091] In step 230, the definitions of the first threshold value and the first SOC threshold value can refer to the relevant description of the above embodiment, which will not be repeated here. The first battery 11 and the second battery 12 can be discharged from each other during the entire heating stage. During the process of the first battery 11 and the second battery 12 discharging from each other, pulse currents can be generated in the first battery 11 and the second battery 12, respectively, to achieve self-heating of the first battery 11 and the second battery 12.

[0092] It is worth noting that in the pulse charging stage S2 of the first charging stage, the first battery 11 and the second battery 12 can also be discharged from each other by controlling the first module 102. That is, by controlling the first module 102, the first battery 11 and the second battery 12 can be discharged from each other for depolarization in the first charging stage, and the first battery 11 and the second battery 12 can be discharged from each other for heating in the heating stage.

[0093] In the above technical solution, by controlling the first module 102, the first battery 11 and the second battery 12 discharge each other, so that the first battery 11 and the second battery 12 exchange energy, and achieve self-heating during the energy exchange process, while maintaining the power balance of the first battery 11 and the second battery 12, and will not consume the existing power of the first battery 11 and the second battery 12, which is beneficial to shortening the charging time of the first battery 11 and the second battery 12 and improving the charging efficiency.

[0094] According to some embodiments of the present application, the heating stage further comprises: During the mutual discharge of the first battery 11 and the second battery 12, the charging device 101 is controlled to charge the first battery 11 and the second battery 12, and the charging current of the charging device 101 to the first battery 11 and the second battery 12 is smaller than the discharge current of the first battery 11 to the second battery 12, and smaller than the discharge current of the second battery 12 to the first battery 11.

[0095] In other words, during the discharge of the first battery 11 to the second battery 12, the charging current of the charging device 101 to the first battery 11 is less than the discharge current of the first battery 11 to the second battery 12, so that the current flowing through the first battery 11 is negative as a whole, and the current flowing through the second battery 12 is positive. During the discharge of the second battery 12 to the first battery 11, the charging current of the charging device 101 to the second battery 12 is less than the discharge current of the second battery 12 to the first battery 11, so that the current flowing through the first battery 11 is negative as a whole, and the current flowing through the first battery 11 is positive. In this way, during the heating stage, the current flowing through the first battery 11 alternates between positive and negative to form a pulse current, and the current flowing through the second battery 12 alternates between positive and negative to form a pulse current. The pulse current can generate a more concentrated and stronger thermal effect inside the first battery 11 and the second battery 12, thereby facilitating the heating of the batteries.

[0096] In the above technical solution, the battery can be heated and the first battery 11 and the second battery 12 can be charged by the charging device 101 during the heating stage, so that the battery is charged while being heated, further improving the charging efficiency.

[0097] refer to Figure 8 According to some embodiments of the present application, the heating stage further comprises: Step 2301, in response to the temperature of either the first battery 11 or the second battery 12 being less than a first threshold and greater than or equal to a second threshold, during the mutual discharge of the first battery 11 and the second battery 12, controlling the charging device 101 to charge the first battery 11 and the second battery 12 based on a first current; Step 2302 , in response to the temperature of either the first battery 11 or the second battery 12 being less than a second threshold, during the mutual discharge of the first battery 11 and the second battery 12 , controlling the charging device 101 to charge the first battery 11 and the second battery 12 based on a second current.

[0098] The second threshold is smaller than the first threshold, the first current is larger than the second current, and the first current is smaller than the discharge current from the first battery 11 to the second battery 12 and smaller than the discharge current from the second battery 12 to the first battery 11 .

[0099] In step 2301, the current with which the charging device 101 charges the first battery 11 and the second battery 12 is greater than the current with which the charging device 101 charges the first battery 11 and the second battery 12 in step 2302. The charging and discharging operations of the first battery 11 and the second battery 12 in step 2301 and step 2302 are consistent.

[0100] Exemplarily, the second threshold may be minus 20°C, and the first threshold may be minus 10°C.

[0101] In the above technical solution, when the battery temperature is too low, the battery's acceptance of the charging current is too low. In order to reduce damage to the battery, in response to the temperature of either the first battery 11 or the second battery 12 being less than the second threshold, a relatively small second current is used to charge the first battery 11 and the second battery 12. When the battery temperature gradually rises to the first threshold, the battery's acceptance of the charging current is improved. Based on this, in response to the temperature of either the first battery 11 or the second battery 12 being greater than or equal to the second threshold and less than the first threshold, a relatively large first current is used to charge the first battery 11 and the second battery 12 to improve the charging efficiency.

[0102] refer to Fig. 9 According to some embodiments of the present application, the first module 102 includes a switch circuit 1021 and a first energy storage circuit 1022, the negative electrode of the first battery 11 is connected to the positive electrode of the second battery 12, the positive electrode of the first battery 11 is connected to the first end of the switch circuit 1021, the negative electrode of the second battery 12 is connected to the second end of the switch circuit 1021, the switch circuit 1021 is also connected to the first end of the first energy storage circuit 1022, the second end of the first energy storage circuit 1022 is connected to the midpoint of the first battery 11 and the second battery 12, and controlling the first module 102 to make the first battery 11 and the second battery 12 discharge each other includes: By means of the switch circuit 1021, at least one step of discharging the first battery 11 to the first energy storage circuit 1022 and discharging the first energy storage circuit 1022 to the second battery 12 is performed, so that the first battery 11 discharges to the second battery 12, and, Through the switch circuit 1021 , at least one step of the second battery 12 discharging to the first energy storage circuit 1022 and the first energy storage circuit 1022 discharging to the first battery 11 is performed, so that the second battery 12 discharges to the first battery 11 .

[0103] The switch circuit 1021 may include a first connection point, a second connection point, and a third connection point connected to each other through a switch element. The first connection point may be connected to the positive electrode of the first battery 11, the second connection point may be connected to the negative electrode of the second battery 12, and the third connection point may be connected to the first end of the first energy storage circuit 1022. The first connection point may be a node between the first switch circuit 1021 and the positive electrode of the first battery 11, the second connection point may be a node between the switch circuit 1021 and the negative electrode of the second battery 12, and the third connection point may be a node between the first energy storage circuit 1022 and the switch circuit 1021.

[0104] The first connection point, the second connection point and the third connection point are connected to each other through a switch element, that is, any two of the first connection point, the second connection point and the third connection point can be connected through a switch element. Exemplarily, when the first connection point and the third connection point are turned on, the first energy storage circuit 1022 and the first battery 11 form a loop, and when the second connection point and the third connection point are turned on, the first energy storage circuit 1022 and the second battery 12 form a loop.

[0105] It can be understood that the first connection point, the second connection point and the third connection point can also be connected.

[0106] Through the switch circuit 1021, the first battery 11 and the first energy storage circuit 1022 can form a loop, the first battery 11 first releases energy to the first energy storage circuit 1022, and the first energy storage circuit 1022 then releases energy to the second battery 12, so that the first battery 11 discharges to the second battery 12. Similarly, the first energy storage circuit 1022 and the second battery 12 form a loop, the first energy storage circuit 1022 plays the role of temporarily storing energy, and the first energy storage circuit 1022 is used to discharge the second battery 12 to the first battery 11.

[0107] Exemplarily, the steps of discharging the first battery 11 to the first energy storage circuit 1022 and discharging the first energy storage circuit 1022 to the second battery 12 can be continuously performed multiple times through the switching circuit 1021 to maintain the discharge of the first battery 11 to the second battery 12, and the steps of discharging the second battery 12 to the first energy storage circuit 1022 and discharging the first energy storage circuit 1022 to the first battery 11 can be continuously performed multiple times through the switching circuit 1021 to maintain the discharge of the second battery 12 to the first battery 11.

[0108] In the pulse charging stage S2 of the first charging stage, the steps of discharging the first battery 11 to the first energy storage circuit 1022 and the first energy storage circuit 1022 to the second battery 12 can be performed 3 to 5 times, and the steps of discharging the second battery 12 to the first energy storage circuit 1022 and the first energy storage circuit 1022 to the first battery 11 can be performed 3 to 5 times.

[0109] In the heating stage, the steps of discharging the first battery 11 to the first energy storage circuit 1022 and the first energy storage circuit 1022 to the second battery 12 and the steps of discharging the second battery 12 to the first energy storage circuit 1022 and the first energy storage circuit 1022 to the first battery 11 may be performed 5 times or more. Exemplarily, the heating stage may include a first heating stage and a second heating stage, in which the steps of discharging the first battery 11 to the first energy storage circuit 1022 and the first energy storage circuit 1022 to the second battery 12 are repeated multiple times, and in the second heating stage, the steps of discharging the second battery 12 to the first energy storage circuit 1022 and the first energy storage circuit 1022 to the first battery 11 are repeated multiple times. The first heating stage and the second heating stage may be performed alternately multiple times to improve the heating efficiency.

[0110] In both the pulse charging stage S2 and the heating stage of the first charging stage, the charging device 101 can be controlled to charge the first battery 11 and the second battery 12 .

[0111] refer to Figure 6 , in the process of the first battery 11 releasing energy to the first energy storage circuit 1022, the current flowing through the first battery 11 is the current obtained by superimposing the charging current input by the charging device 101 to the first battery 11 and the discharge current of the first battery 11 to the first energy storage circuit 1022. In the case where the charging current input by the charging device 101 to the first battery 11 is less than the discharge of the first battery 11 to the first energy storage circuit 1022, the current of the first battery 11 during this period is a negative current. In the process of the first energy storage circuit 1022 releasing current to the second battery 12, the discharge current of the first battery 11 is zero, and the current flowing through the first battery 11 is the charging current input by the charging device 101 to the first battery 11, which is a positive current. In the case of performing the steps of discharging the first battery 11 to the first energy storage circuit 1022 and discharging the first energy storage circuit 1022 to the second battery 12 multiple times, the current flowing through the first battery 11 alternates between a negative current and a positive current, thereby forming a pulse current.

[0112] Similarly, in the pulse charging stage S2 and the heating stage of the first charging stage, the charging device 101 charges the first battery 11 and the second battery 12, and performs the steps of discharging the second battery 12 to the first energy storage circuit 1022 and discharging the first energy storage circuit 1022 to the first battery 11 multiple times. The current flowing through the second battery 12 alternates between negative current and positive current, forming a pulse current.

[0113] In the pulse charging stage S2 and the heating stage of the first charging stage, when the charging device 101 is controlled to charge the first battery 11 and the second battery 12, the current flowing through the first battery 11 can refer to Figure 2 . Figure 2The current flowing through the first battery 11 in the pulse charging phase S2 or the heating phase of the first charging phase can be characterized. Figure 2 In the stage where multiple negative pulse currents and multiple positive pulse currents alternate, the first battery 11 discharges to the second battery 12, and the stage where multiple positive pulse currents are continuous is the stage where the second battery 12 discharges to the first battery 11. For the current flowing through the second battery 12 in the pulse charging stage S2 or the heating stage of the first charging stage, it is only necessary to Figure 2 The order of the stage in which multiple positive pulse currents are continuous and the stage in which multiple negative pulse currents and multiple positive pulse currents alternate is swapped, that is, the stage in which multiple positive pulse currents are continuous is in the front, and the stage in which multiple negative pulse currents and multiple positive pulse currents alternate is in the back.

[0114] In some embodiments, in step 2302, the absolute value of the discharge current of the first battery 11 to the second battery 12 is twice the absolute value of the second current, and the absolute value of the discharge current of the second battery 12 to the first battery 11 is twice the absolute value of the second current. In this way, during the discharge process of the first battery 11 to the second battery 12, the absolute values ​​of the alternating positive current and negative current flowing through the first battery 11 are equal, so that the energy loss during the discharge process of the first battery 11 to the second battery 12 is provided by the charging device 101. Similarly, during the discharge process of the second battery 12 to the first battery 11, the energy loss of the second battery 12 is provided by the charging device 101, which can effectively shorten the charging time.

[0115] In the above technical solution, the first energy storage circuit 1022 plays the role of temporarily storing energy. Through the first energy storage circuit 1022, the discharge speed of the first battery 11 and the second battery 12 can be controlled, so that the discharge amount of the first battery 11 and the second battery 12 each time is not too much, and the probability of the first battery 11 and the second battery 12 being out of power is reduced. In addition, in the pulse charging stage S2 and the heating stage of the first charging stage, when the control device charges the first battery 11 and the second battery 12, since the first energy storage circuit 1022 plays the role of temporarily storing energy, the current flowing through the first battery 11 during the discharge of the first battery 11 to the first energy storage circuit 1022 is negative, and the current flowing through the first battery 11 during the discharge of the first energy storage circuit 1022 to the second battery 12 is positive, so that a pulse current can be formed in the first battery 11, and similarly, a pulse current can be formed in the second battery 12, thereby respectively realizing depolarization and heating of the first battery 11 and the second battery 12.

[0116] refer to Fig.10 According to some embodiments of the present application, a second energy storage circuit 1023 is connected in parallel to both ends of the first battery 11 and the second battery 12 connected in series, and the method further includes: Through the switch circuit 1021, the first battery 11 discharges to the first energy storage circuit 1022 and the second energy storage circuit 1023 discharges to the second battery 12, and the first energy storage circuit 1022 discharges to the second battery 12 and the first battery 11 discharges to the second energy storage circuit 1023; and / or, Through the switch circuit 1021, the second battery 12 discharges to the first energy storage circuit 1022 and the second energy storage circuit 1023 discharges to the first battery 11 at the same time, and the first energy storage circuit 1022 discharges to the first battery 11 and the second battery 12 discharges to the second energy storage circuit 1023 at the same time.

[0117] Since the switch circuit 1021 is also connected in parallel with the first battery 11 and the second battery 12 connected in series, it is equivalent to that the second energy storage circuit 1023 is connected in parallel with the switch circuit 1021, and the switch circuit 1021 is connected with the first energy storage circuit 1022. In this way, the second energy storage circuit 1023 can be connected to the midpoint of the first battery 11 and the second battery 12 through the switch circuit 1021 and the first energy storage circuit 1022, and then the above steps can be performed.

[0118] During the period when the first battery 11 and the first energy storage circuit 1022 form a loop so that the first battery 11 discharges to the first energy storage circuit 1022, the second energy storage circuit 1023 can form a loop with the second battery 12 so that the second energy storage circuit 1023 discharges to the second battery 12, so that current flows through the second battery 12. During the period when the first energy storage circuit 1022 and the second battery 12 form a loop so that the first energy storage circuit 1022 discharges to the second battery 12, the second energy storage circuit 1023 can form a loop with the first battery 11 so that the first battery 11 discharges to the second energy storage circuit 1023, so that current flows through the first battery 11.

[0119] During the period when the second battery 12 and the first energy storage circuit 1022 form a loop so that the second battery 12 discharges to the first energy storage circuit 1022, the second energy storage circuit 1023 can form a loop with the first battery 11 so that the second energy storage circuit 1023 discharges to the first battery 11, thereby allowing current to flow through the first battery 11. During the period when the first energy storage circuit 1022 and the first battery 11 form a loop so that the first energy storage circuit 1022 discharges to the first battery 11, the second energy storage circuit 1023 can form a loop with the second battery 12 so that the second battery 12 discharges to the second energy storage circuit 1023, thereby allowing current to flow through the second battery 12.

[0120] The second energy storage circuit 1023 may include, but is not limited to, a capacitor.

[0121] In the above technical solution, during the period when the first battery 11 discharges to the second battery 12 and during the period when the second battery 12 discharges to the first battery 11, current continues to flow through the first battery 11 and the second battery 12, which is beneficial to maintaining the stability of the circuit.

[0122] refer to Figures 11 to 14 According to some embodiments of the present application, the switch circuit 1021 includes: a bridge arm 20, including an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm is connected to the positive electrode of the first battery 11, the lower bridge arm is connected to the negative electrode of the second battery 12, and the first end of the first energy storage circuit 1022 is connected between the upper bridge arm and the lower bridge arm; The step of performing at least one of discharging the first battery 11 to the first energy storage circuit 1022 and discharging the first energy storage circuit 1022 to the second battery 12 through the switch circuit 1021 includes: alternately performing the first step and the second step in sequence, The step of performing at least one of discharging the second battery 12 to the first energy storage circuit 1022 and discharging the first energy storage circuit 1022 to the first battery 11 through the switch circuit 1021 includes: alternately performing the second step and the first step in sequence; wherein, The first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; The second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

[0123] The upper bridge arm includes an upper bridge arm switch tube V1, and the lower bridge arm includes a lower bridge arm switch tube V2. The upper bridge arm can be turned on / off by turning on / off the upper bridge arm switch tube V1, and the lower bridge arm can be turned on / off by turning on / off the lower bridge arm switch tube V2. The types of the upper bridge arm switch tube V1 and the lower bridge arm switch tube V2 include but are not limited to MOS tubes (Metal-Oxide-Semiconductor Field-Effect Transistor) or IGBT tubes (Insulate-Gate Bipolar Transistor, insulated gate bipolar transistors), etc. The upper bridge arm switch tube and the lower bridge arm switch tube can be the switching elements in the above-mentioned switching circuit 1021.

[0124] By controlling the conduction time of the upper bridge arm switch tube or the lower bridge arm switch tube, the current magnitude of the discharge from the first battery 11 to the second battery 12 can be controlled, and the current magnitude of the discharge from the second battery 12 to the first battery 11 can be controlled.

[0125] In the step of discharging the first battery 11 to the second battery 12, the first step is first performed, and then the second step is performed, and the first step and the second step are performed alternately. The first step is performed so that the first battery 11 forms a loop through the upper bridge arm and the first energy storage circuit 1022, so that the first battery 11 discharges to the first energy storage circuit 1022. The second step is performed so that the second battery 12 forms a loop with the first energy storage circuit 1022 through the lower bridge arm, so that the first energy storage circuit 1022 discharges to the second battery 12.

[0126] In some embodiments, the first energy storage circuit 1022 is an inductor. Fig.11 As shown, the first step is performed, the upper bridge arm is turned on, the lower bridge arm is turned off, the first battery 11, the upper bridge arm and the inductor form a loop, the current flows from the positive electrode of the first battery 11 through the upper bridge arm and the inductor, and then flows back to the negative electrode of the first battery 11, and the inductor stores energy. Fig.11 The solid line with an arrow in the middle shows the current path for discharging the first battery 11 to the inductor.

[0127] like Fig.12 As shown, the second step is executed, the lower bridge arm is turned on, the upper bridge arm is turned off, the inductor, the lower bridge arm and the second battery 12 form a loop, and the current flows from the inductor through the positive electrode of the second battery 12, the negative electrode of the second battery 12 and the lower bridge arm and then flows back to the inductor, that is, the inductor releases energy to the second battery 12. Fig.12 The solid line with an arrow in the middle shows the current path for discharging the inductor to the second battery 12 .

[0128] In the step of the second battery 12 discharging to the first battery 11, the second step is first performed, and then the first step is performed, and the second step and the first step are performed alternately. The second step is performed so that the second battery 12 forms a loop through the upper bridge arm and the first energy storage circuit 1022, so that the second battery 12 discharges to the first energy storage circuit 1022. The first step is performed so that the first battery 11 forms a loop with the first energy storage circuit 1022 through the lower bridge arm, so that the first energy storage circuit 1022 discharges to the first battery 11.

[0129] In some embodiments, the first energy storage circuit 1022 is an inductor. Fig.13 As shown, the second step is performed, the lower bridge arm is turned on, the upper bridge arm is turned off, the second battery 12, the lower bridge arm and the inductor form a loop, the current flows from the positive electrode of the second battery 12 through the lower bridge arm and the inductor, and then flows back to the negative electrode of the second battery 12, and the inductor stores energy. Fig.13 The solid line with an arrow in it shows the current path for discharging the second battery 12 to the inductor.

[0130] like Fig.14As shown, the first step is executed, the upper bridge arm is turned on, the lower bridge arm is turned off, the first energy storage circuit 1022, the upper bridge arm and the first battery 11 form a loop, and the current flows from the inductor through the positive electrode of the first battery 11, the negative electrode of the first battery 11 and the upper bridge arm and then flows back to the inductor, that is, the inductor releases energy to the first battery 11. Fig.14 The solid line with an arrow in the middle shows the current path for discharging the inductor to the first battery 11 .

[0131] In some embodiments, the upper bridge arm switch tube V1 is correspondingly provided with a first freewheeling diode D1, and the lower bridge arm switch tube V2 is correspondingly provided with a second freewheeling diode D2. In the gap between the first step switching to the second step, that is, when the upper bridge arm switches from on to off, the current can flow from the first freewheeling diode D1, so that during the period from the first step switching to the second step, the current is always kept flowing through the inductor. Similarly, during the period from the second step switching to the first step, the current can flow from the second freewheeling diode D2, so that during the period from the second step switching to the first step, the current is always flowing through the inductor, so that the rate of change of the current passing through the inductor is small, and the frequency of the current flowing through the inductor is kept low. In the case where the number of inductors is multiple, and the multiple inductors are three-phase inductors in the motor, the problem of high-frequency howling of the motor caused by excessive current flowing through the motor can be greatly improved, and the performance of the motor can be kept relatively stable to improve the heating efficiency of the battery.

[0132] In some embodiments, there may be multiple bridge arms 20 connected in parallel, and the first energy storage circuit 1022 may include multiple first inductors L1 connected in parallel, and the multiple first inductors L1 are connected to the multiple bridge arms 20 in a one-to-one correspondence.

[0133] In some embodiments, the first energy storage circuit 1022 further includes a second inductor L2, and a plurality of first inductors L1 are connected in parallel and then connected in series with the second inductor L2. In the first step, the first battery 11 discharges to the plurality of first inductors L1 and the second inductor L2. In the second step, the plurality of first inductors L1 and the second inductor L2 discharge to the second battery 12.

[0134] In some embodiments, the second energy storage circuit 1023 is a capacitor, a first end of the capacitor is connected to the positive electrode of the first battery 11 , and a second end of the capacitor is connected to the negative electrode of the second battery 12 .

[0135] During the discharge of the first battery 11 to the second battery 12, the first step is performed, the upper bridge arm is turned on, the lower bridge arm is turned off, and the capacitor forms a loop with the second battery 12 through the upper bridge arm and the inductor to discharge to the second battery 12. Then the second step is performed, the lower bridge arm is turned on, the upper bridge arm is turned off, and the capacitor forms a loop with the first battery 11 through the lower bridge arm and the inductor to discharge the first battery 11 to the inductor.

[0136] During the discharge of the second battery 12 to the first battery 11, the second step is performed, the lower bridge arm is turned on, the upper bridge arm is turned off, and the capacitor forms a loop with the first battery 11 through the lower bridge arm and the inductor to discharge to the first battery 11. Then the first step is performed, the upper bridge arm is turned on, the lower bridge arm is turned off, and the capacitor forms a loop with the second battery 12 through the upper bridge arm and the inductor to discharge the second battery 12 to the inductor.

[0137] In some embodiments, when the first energy storage circuit 1022 is an inductor, during the pulse charging stage S2 and the heating stage of the first charging stage, the inductor satisfies the volt-second product balance.

[0138] During the execution of the first step and the second step, the charging device can continuously charge the first battery and the second battery to form alternating positive pulse current and negative pulse current in the first battery and the second battery. The current path of the charging device for charging the first battery and the second battery is as follows: Figures 11 to 14 Indicated by the dashed line with arrow.

[0139] In the above technical solution, by controlling the alternating conduction of the upper bridge arm and the lower bridge arm, the mutual charging and discharging of the first battery 11 and the second battery 12 can be realized, which is simple to operate and simplifies the battery charging control method.

[0140] The embodiment of the present application provides a battery charging control circuit, wherein the number of batteries is two, the two batteries are connected in series, and the two batteries are connected in series to an external charging device 101, the charging control circuit comprises: a first module, connected to the battery; a controller, communicatively connected to the charging device 101, the controller being configured to: control the charging device 101 to charge the battery, and control the battery to be in N first charging stages in sequence according to the charge state of the battery, N being an integer greater than 1: wherein the SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, n is an integer, 1≤n≤N-1, each first charging stage comprises: a constant current charging stage S1 and a pulse charging stage S2, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage S2 comprises: controlling the first module 102 to discharge the two batteries to each other.

[0141] The controller can pre-store instructions and control the charging device 101 to charge the battery based on the pre-stored instructions, so as to execute the step of controlling the battery to be in N first charging stages in sequence according to the charge state of the battery. The method for the controller to execute this step can refer to the relevant description of the above embodiment, which will not be repeated here.

[0142] In some embodiments, the BMS may include, but is not limited to, a MCU (Microcontroller Unit) of a vehicle, or a controller in a BMS of a battery.

[0143] In the above technical solution, as the SOC gradually increases, the corresponding constant current charging current of the first charging stage becomes lower, so that a certain charging speed can be guaranteed and overcharging can be avoided to a certain extent to cause damage to the battery. At the same time, each first charging stage includes a pulse charging stage S2, in which the two batteries discharge each other, so that in the pulse charging stage S2, the current flowing through the two batteries includes a positive pulse current and a negative pulse current, which can achieve self-discharge of the battery. During the discharge process, the charge accumulated on the electrode of the battery decreases rapidly, which can improve the polarization phenomenon of the battery and enhance the battery's acceptance of the charging current, so that compared with the case without the pulse charging stage S2, the charging current of each first charging stage is increased, further shortening the charging time of the battery and improving the charging efficiency of the battery. In addition, since the two batteries discharge each other, it is possible to achieve depolarization of the two batteries without consuming the existing power of the two batteries, thereby further shortening the charging time of the battery and improving the charging efficiency of the battery as a whole.

[0144] According to some embodiments of the present application, the controller is further configured to: control the constant current charging stage S1 to be executed before the pulse charging stage S2.

[0145] That is, before switching to the next first charging stage, the battery is controlled to be in the pulse charging stage S2, and after the pulse charging stage S2 ends, it enters the constant current charging stage S1 of the next first charging stage.

[0146] In the above technical solution, it is possible to put the battery in the pulse charging stage S2 when the previous first charging stage is about to switch to the next first charging stage, so that before the battery switches to the next first charging stage, the battery is depolarized to improve the battery's ability to accept the charging current, which is beneficial to improve the maximum current that can charge the battery in the next first charging stage, and then in the next first charging stage, a larger constant current charging current can be used to charge the battery, further shortening the charging time and improving the charging efficiency.

[0147] According to some embodiments of the present application, the controller is also configured to: obtain the temperature of the battery during the charging process; in response to the battery temperature being greater than or equal to a first threshold, control the battery to be in N first charging stages in sequence according to the battery's state of charge; in response to the battery temperature being less than the first threshold and the battery's SOC being greater than a first SOC threshold, control the battery to be in a heating stage, and in the heating stage, use a pulse current to heat the battery.

[0148] That is to say, the controller can execute steps 110 to 130 in the above embodiment. The execution method of steps 110 to 130 can refer to the relevant description of the above embodiment, which will not be repeated below.

[0149] In the above technical solution, when the battery temperature is less than the first threshold, the battery temperature itself is low, and a pulse current is used to heat the battery to increase the battery temperature. When the battery temperature reaches the first threshold, the activity of the battery electrode material increases, and the overall charge and discharge performance of the battery is improved. At this time, the battery is controlled to be in N first charging stages in sequence, which is conducive to further improving the charging efficiency of the battery during each first charging stage.

[0150] According to some embodiments of the present application, the two batteries are respectively a first battery 11 and a second battery 12, and the controller is further configured to: in a first charging stage, during the period when the first battery 11 and the second battery 12 discharge each other, control the charging device 101 to charge the first battery 11 and the second battery 12, and the charging current of the charging device 101 to the first battery 11 and the second battery 12 is less than the discharge current of the first battery 11 to the second battery 12, and less than the discharge current of the second battery 12 to the first battery 11.

[0151] The method for the controller to execute the above steps can refer to the relevant description in the above embodiment, which will not be repeated here.

[0152] In the above technical solution, by controlling the charging current of the charging device 101 to be smaller than the discharge current of the first battery 11 to the second battery 12, and smaller than the discharge current of the second battery 12 to the first battery 11, during the mutual discharge of the first battery 11 and the second battery 12, the current flowing through the first battery 11 and the second battery 12 can form a negative pulse current to depolarize the first battery 11 and the second battery 12. At the same time, since the mutual discharge of the first battery 11 and the second battery 12 is essentially an energy exchange, not only can the depolarization of the first battery 11 and the second battery 12 be achieved, but also the original power of the first battery 11 and the second battery 12 will not be consumed. On this basis, the charging device 101 charges the first battery 11 and the second battery 12, which can further shorten the charging time and further improve the charging efficiency.

[0153] According to some embodiments of the present application, the controller is further configured to: obtain the temperature of the first battery 11 and the second battery 12 during the charging process; in response to the temperature of the first battery 11 and the second battery 12 being greater than or equal to a first threshold, control the first battery 11 and the second battery 12 to be in N first charging stages in sequence according to the charge state of the first battery 11 and the second battery 12; in response to the temperature of either the first battery 11 and the second battery 12 being less than the first threshold, and the SOC of the first battery 11 and the second battery 12 being greater than the first SOC threshold, control the first battery 11 and the second battery 12 to be in a heating stage, and the heating stage includes: controlling the first module 102 to cause the first battery 11 and the second battery 12 to discharge each other.

[0154] That is to say, the controller can execute the above steps 210 to 230. For the method of executing the above steps 210 to 230, reference can be made to the relevant description in the above embodiment, which will not be repeated here.

[0155] In the above technical solution, by controlling the first module 102, the first battery 11 and the second battery 12 discharge each other, so that the first battery 11 and the second battery 12 exchange energy, and achieve self-heating during the energy exchange process, while maintaining the power balance of the first battery 11 and the second battery 12, and will not consume the existing power of the first battery 11 and the second battery 12, which is beneficial to shortening the charging time of the first battery 11 and the second battery 12 and improving the charging efficiency.

[0156] According to some embodiments of the present application, the controller is further configured to: in the heating stage, during the period when the first battery 11 and the second battery 12 discharge each other, control the charging device 101 to charge the first battery 11 and the second battery 12, and the charging current of the charging device 101 to the first battery 11 and the second battery 12 is smaller than the discharge current of the first battery 11 to the second battery 12, and smaller than the discharge current of the second battery 12 to the first battery 11.

[0157] In other words, during the period when the first battery 11 discharges to the second battery 12, the charging current of the charging device 101 to the first battery 11 is less than the discharging current of the first battery 11 to the second battery 12, so that the current flowing through the first battery 11 is negative as a whole, and the current flowing through the second battery 12 is positive. During the period when the second battery 12 discharges to the first battery 11, the charging current of the charging device 101 to the second battery 12 is less than the discharging current of the second battery 12 to the first battery 11, so that the current flowing through the first battery 11 is negative as a whole, and the current flowing through the first battery 11 is positive.

[0158] In the above technical solution, the battery can be heated and the first battery 11 and the second battery 12 can be charged by the charging device 101 during the heating stage, so that the battery is charged while being heated, further improving the charging efficiency.

[0159] According to some embodiments of the present application, the controller is further configured to: in a heating stage, in response to the temperature of either the first battery 11 and the second battery 12 being less than a first threshold value and greater than or equal to a second threshold value, during a period in which the first battery 11 and the second battery 12 discharge each other, control the charging device 101 to charge the first battery 11 and the second battery 12 based on a first current, and the second threshold value is less than the first threshold value; in response to the temperature of either the first battery 11 and the second battery 12 being less than a second threshold value, during a period in which the first battery 11 and the second battery 12 discharge each other, control the charging device 101 to charge the first battery 11 and the second battery 12 based on a second current, wherein the first current is greater than the second current, and the first current is less than a discharge current from the first battery 11 to the second battery 12, and less than a discharge current from the second battery 12 to the first battery 11.

[0160] That is to say, the controller can execute step 2301 and step 2302 in the above embodiment. For the method of executing step 2301 and step 2302, reference can be made to the relevant description in the above embodiment, which will not be repeated here.

[0161] In the above technical solution, in response to the temperature of either the first battery 11 or the second battery 12 being less than the second threshold, the first battery 11 and the second battery 12 are charged with a relatively small second current to reduce damage to the battery. When the temperature of the battery gradually rises to the first threshold, in response to the temperature of either the first battery 11 or the second battery 12 being greater than or equal to the second threshold and less than the first threshold, the first battery 11 and the second battery 12 are charged with a relatively large first current to improve charging efficiency.

[0162] refer to Fig. 9 According to some embodiments of the present application, the negative electrode of the first battery 11 is connected to the positive electrode of the second battery 12, and the first module 102 includes: a switch circuit 1021 and a first energy storage circuit 1022. The positive electrode of the first battery 11 is connected to the first end of the switch circuit 1021, and the negative electrode of the second battery 12 is connected to the second end of the switch circuit 1021. The first end of the first energy storage circuit 1022 is connected to the switch circuit 1021, and the second end is connected to the midpoint of the first battery 11 and the second battery 12; the controller is configured to: through the switch circuit 1021, perform at least one step of the first battery 11 discharging to the first energy storage circuit 1022 and the first energy storage circuit 1022 discharging to the second battery 12, so that the first battery 11 discharges to the second battery 12, and, through the switch circuit 1021, perform at least one step of the second battery 12 discharging to the first energy storage circuit 1022 and the first energy storage circuit 1022 discharging to the first battery 11, so that the second battery 12 discharges to the first battery 11.

[0163] For the structures of the switch circuit 1021 and the first energy storage circuit 1022 and the method of charging and discharging the first battery 11 and the second battery 12 through the switch circuit 1021 and the first energy storage circuit 1022, reference may be made to the relevant descriptions in the above embodiments. The controller may control the switch circuit 1021 to be turned on and off according to the method described in the above embodiments, so that the first battery 11 and the second battery 12 are charged and discharged.

[0164] In the above technical solution, the first energy storage circuit 1022 plays the role of temporarily storing energy. Through the first energy storage circuit 1022, the discharge speed of the first battery 11 and the second battery 12 can be controlled, so that the discharge amount of the first battery 11 and the second battery 12 each time is not too much, and the probability of the first battery 11 and the second battery 12 being out of power is reduced. In addition, in the pulse charging stage S2 and the heating stage of the first charging stage, when the control device charges the first battery 11 and the second battery 12, since the first energy storage circuit 1022 plays the role of temporarily storing energy, the current flowing through the first battery 11 during the discharge of the first battery 11 to the first energy storage circuit 1022 is negative, and the current flowing through the first battery 11 during the discharge of the first energy storage circuit 1022 to the second battery 12 is positive, so that a pulse current can be formed in the first battery 11, and similarly, a pulse current can be formed in the second battery 12, thereby respectively realizing depolarization and heating of the first battery 11 and the second battery 12.

[0165] refer to Fig.10 According to some embodiments of the present application, the battery charging control circuit further includes: a second energy storage circuit 1023, which is connected in parallel with the first battery 11 and the second battery 12 connected in series; the controller is also configured to: through the switch circuit 1021, simultaneously execute the discharge of the first battery 11 to the first energy storage circuit 1022 and the discharge of the second energy storage circuit 1023 to the second battery 12, and simultaneously execute the discharge of the first energy storage circuit 1022 to the second battery 12 and the discharge of the first battery 11 to the second energy storage circuit 1023; and / or, through the switch circuit 1021, simultaneously execute the discharge of the second battery 12 to the first energy storage circuit 1022 and the discharge of the second energy storage circuit 1023 to the first battery 11, and simultaneously execute the discharge of the first energy storage circuit 1022 to the first battery 11 and the discharge of the second battery 12 to the second energy storage circuit 1023.

[0166] For the connection mode between the second energy storage circuit 1023 and the first battery 11 and the second battery 12 and the method for mutual charging and discharging of the first battery 11 and the second battery 12 through the second energy storage circuit 1023, reference may be made to the relevant description of the above embodiment, which will not be repeated here.

[0167] In the above technical solution, by setting the second energy storage circuit 1023, during the period when the first battery 11 discharges to the second battery 12, and during the period when the second battery 12 discharges to the first battery 11, current continues to flow through the first battery 11 and the second battery 12, which is beneficial to maintaining the stability of the circuit.

[0168] According to some embodiments of the present application, the first energy storage circuit 1022 includes at least one inductor, and the second energy storage circuit 1023 includes a capacitor.

[0169] In some embodiments, the first energy tank circuit 1022 may include an inductor.

[0170] In some other embodiments, the first energy storage circuit 1022 may also include a plurality of inductors, and the plurality of inductors may be connected in parallel or in series, or some of the plurality of inductors may be connected in parallel and then connected in series with the remaining inductors.

[0171] The principle and method of making the first battery 11 and the second battery 12 discharge each other through the inductor and the capacitor can refer to the relevant description in the above embodiment, which will not be repeated here.

[0172] In the above technical solution, the inductor can store a large amount of electricity, which can improve the energy transfer efficiency from the first battery 11 to the second battery 12, thereby improving the heating efficiency of the battery. Compared with the inductor, the capacitor is smaller in size, and the capacitor can achieve rapid charging and discharging, so that during the entire period when the first battery 11 and the second battery 12 discharge each other, there is always current flowing through the first battery 11 and the second battery 12, which is conducive to maintaining the stability of the current flowing through the first battery 11 and the second battery 12, and at the same time, keeping the size of the circuit for heating the battery small, saving costs.

[0173] refer to Figures 11 to 14 According to some embodiments of the present application, the switch circuit 1021 includes: a bridge arm 20, including an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm is connected to the positive electrode of the first battery 11, the lower bridge arm is connected to the negative electrode of the second battery 12, and the first end of the first energy storage circuit 1022 is connected between the upper bridge arm and the lower bridge arm; the controller is configured to: alternately perform the first step and the second step in sequence to make the first battery 11 discharge to the second battery 12, and alternately perform the second step and the first step in sequence to make the second battery 12 discharge to the first battery 11; wherein the first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; the second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

[0174] For the structure of the bridge arm 20, the method of alternately executing the first step and the second step in sequence to make the first battery 11 discharge to the second battery 12, and the method of alternately executing the second step and the first step in sequence to make the second battery 12 discharge to the first battery 11, reference can be made to the relevant description in the above embodiments, which will not be repeated here.

[0175] The upper and lower bridge arms in the bridge arm 20 can be turned on / off by a controller, and the controller can be executed according to the on / off sequence of the upper and lower bridge arms as described in the above embodiment, so that the first battery 11 and the second battery 12 discharge each other.

[0176] like Figures 11 to 14 As shown, the battery charging control circuit also includes a first switch K1 and a second switch K2. The first end of the first switch K1 is connected to the positive electrode of the first battery 11, and the second end of the first switch K1 is connected to the upper bridge arm, which is used to control the connection / disconnection between the positive electrode of the first battery 11 and the upper bridge arm. The first end of the second switch K2 is connected to the negative electrode of the second battery 12, and the second end of the second switch K2 is connected to the lower bridge arm, which is used to control the connection / disconnection between the negative electrode of the second battery 12 and the lower bridge arm. In this way, when the first battery 11 and the second battery 12 need to discharge each other, the first switch K1 and the second switch K2 can be used to control the connection between the battery and the bridge arm 20. When the first battery 11 and the second battery 12 do not need to discharge each other, the first switch K1 and the second switch K2 can be used to control the disconnection between the first battery 11 and the second battery 12 and the bridge arm 20, so as not to affect the normal performance of the first battery 11 and the second battery 12.

[0177] In some embodiments, the first switch K1 may be connected to the upper bridge arm through the first connector 24 , and the second switch K2 may be connected to the lower bridge arm through the second connector 25 .

[0178] In some embodiments, the battery charging control circuit further includes a third switch K3 and a first resistor R1 connected in parallel with the second switch K2. The third switch and the first resistor are connected in series to play a role of current limiting protection.

[0179] In some embodiments, the battery charging control circuit also includes a current sensor 23, which is connected between the first battery and the first switch K1 and is used to detect the current output by the battery, so as to facilitate the regulation of the current used for battery heating in the battery charging control circuit to produce a better heating effect on the battery.

[0180] In some embodiments, the first switch K1 , the second switch K2 , and the third switch K3 may include, but are not limited to, relays.

[0181] In some embodiments, the battery charging control circuit also includes a fourth switch V3, which connects the first energy storage circuit 1022 and the midpoint between the first battery 11 and the second battery 12, and is used to control the on and off of the first energy storage circuit 1022 and the midpoint between the first battery 11 and the second battery 12. The fourth switch V3 may include but is not limited to any one of a MOS tube or an IGBT tube.

[0182] In the above technical solution, by controlling the alternating conduction of the upper bridge arm and the lower bridge arm, the mutual charging and discharging of the first battery 11 and the second battery 12 can be realized, which is simple to operate and simplifies the battery charging control circuit.

[0183] An embodiment of the present application provides a battery device, comprising the battery charging control circuit in the above embodiment.

[0184] The battery device may include a battery connected to a battery charging control circuit. The battery device has the beneficial effects of the battery charging control circuit provided by the embodiment of the present application. For details, please refer to the specific description of the battery charging control circuit in the above embodiments, which will not be repeated here.

[0185] An embodiment of the present application provides an electrical device, including the battery device in the above embodiment, and the battery device supplies power to the electrical device.

[0186] The electrical device may refer to the relevant description in the above embodiments, which will not be described in detail below.

[0187] An embodiment of the present application provides an energy storage device, including the battery device in the above embodiment, and the battery device is used to store electrical energy.

[0188] The energy storage device can be, but is not limited to, an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable The embodiment of the present application provides a battery charging method, wherein the number of batteries is two, namely a first battery 11 and a second battery 12, the first battery 11 and the second battery 12 are connected in series, the negative electrode of the first battery 11 is connected to the positive electrode of the second battery 12, and the first battery 11 and the second battery 12 are connected in series to an external charging device 101, the first battery 11 and the second battery 12 are connected to a bridge arm 20 and an inductor, wherein the bridge arm 20 includes an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm is connected to the positive electrode of the first battery 11, and the lower bridge arm is connected to the negative electrode of the second battery 12, the first end of the inductor is connected between the upper bridge arm and the lower bridge arm, and the second end of the inductor is connected to the midpoint of the first battery 11 and the second battery 12, and the battery charging method comprises: Acquire the temperature of the first battery 11 and the second battery 12 during the charging process; In response to the temperature of the first battery 11 and the second battery 12 being greater than or equal to the first threshold, the first battery 11 and the second battery 12 are respectively controlled to be in N first charging stages in sequence according to the charge state of the first battery 11 and the second battery 12; wherein the SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, and each first charging stage includes: a constant current charging stage S1 and a pulse charging stage S2, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage S2 includes: through the bridge arm 20 and the inductor, the first battery 11 and the second battery 12 are discharged to each other; In response to the temperature of either the first battery 11 or the second battery 12 being less than the first threshold value, and the SOC of the first battery 11 or the second battery 12 being greater than the first SOC threshold value, the first battery 11 or the second battery 12 is controlled to be in a heating stage, and the heating stage includes: discharging the first battery 11 or the second battery 12 to each other through the bridge arm 20 and the inductor.

[0189] The first step and the second step are alternately performed at least once in sequence to make the first battery 11 discharge to the second battery 12, and the second step and the first step are alternately performed at least once in sequence to make the second battery 12 discharge to the first battery 11. The first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; the second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

[0190] In the first charging stage, during the period when the first battery 11 and the second battery 12 discharge each other, the charging device 101 is also controlled to charge the first battery 11 and the second battery 12, and the charging current of the charging device 101 to the first battery 11 and the second battery 12 is smaller than the discharge current of the first battery 11 to the second battery 12, and smaller than the discharge current of the second battery 12 to the first battery 11.

[0191] In the heating stage, during the mutual discharge of the first battery 11 and the second battery 12, the charging device 101 is controlled to charge the first battery 11 and the second battery 12, and in response to the temperature of either the first battery 11 and the second battery 12 being less than the first threshold and greater than or equal to the second threshold, during the mutual discharge of the first battery 11 and the second battery 12, the charging device 101 is controlled to charge the first battery 11 and the second battery 12 based on the first current, and the second threshold is less than the first threshold; in response to the temperature of either the first battery 11 and the second battery 12 being less than the second threshold, during the mutual discharge of the first battery 11 and the second battery 12, the charging device 101 is controlled to charge the first battery 11 and the second battery 12 based on the second current. The first current is greater than the second current, the first current is less than the discharge current of the first battery 11 to the second battery 12, and less than the discharge current of the second battery 12 to the first battery 11, wherein the absolute value of the discharge current of the first battery 11 to the second battery 12 is twice the absolute value of the second current, and the absolute value of the discharge current of the second battery 12 to the first battery 11 is twice the absolute value of the second current.

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery charging method, characterized in that: include: According to the state of charge of the battery, the battery is controlled to be in N first charging stages in sequence, N is an integer, N≥2, the number of the battery is two, the two batteries are connected in series, and the two batteries are connected in series to an external charging device, and the battery is also connected to the first module; wherein, The SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, n is an integer, 1≤n≤N-1, each of the first charging stages includes: a constant current charging stage and a pulse charging stage, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage includes: controlling the first module to make the two batteries discharge each other.

2. The method according to claim 1, characterized in that In each of the first charging stages, the constant current charging stage is controlled to be performed before the pulse charging stage.

3. The method according to claim 1, characterized in that The method further comprises: Obtaining the temperature of the battery during charging; In response to a temperature of the battery being greater than or equal to a first threshold, controlling the battery to be in N first charging stages in sequence according to a state of charge of the battery; In response to the temperature of the battery being less than the first threshold and the SOC of the battery being greater than a first SOC threshold, the battery is controlled to be in a heating stage, in which a pulse current is used to heat the battery.

4. The method according to claim 1, characterized in that The two batteries are respectively a first battery and a second battery. In the first charging stage, during the period when the first battery and the second battery discharge each other, the charging device is also controlled to charge the first battery and the second battery, and the charging current of the charging device for the first battery and the second battery is smaller than the discharge current of the first battery to the second battery, and smaller than the discharge current of the second battery to the first battery.

5. The method according to claim 1, characterized in that The two batteries are respectively a first battery and a second battery, and the method further comprises: Acquire temperatures of the first battery and the second battery during charging; In response to the temperature of the first battery and the second battery being greater than or equal to a first threshold, controlling the first battery and the second battery to be in N first charging stages in sequence according to the charge states of the first battery and the second battery; In response to the temperature of either the first battery or the second battery being less than the first threshold, and the SOC of the first battery or the second battery being greater than a first SOC threshold, controlling the first battery or the second battery to be in a heating stage, wherein the heating stage includes: The first module is controlled to make the first battery and the second battery discharge each other.

6. The method according to claim 5, characterized in that The heating stage also includes: During the mutual discharge of the first battery and the second battery, the charging device is controlled to charge the first battery and the second battery, and the charging current of the charging device for the first battery and the second battery is smaller than the discharge current of the first battery to the second battery, and smaller than the discharge current of the second battery to the first battery.

7. The method according to claim 6, characterized in that The heating stage also includes: In response to a temperature of either the first battery or the second battery being less than a first threshold and greater than or equal to a second threshold, during a period in which the first battery and the second battery discharge each other, controlling the charging device to charge the first battery and the second battery based on a first current, the second threshold being less than the first threshold; In response to the temperature of either the first battery and the second battery being less than the second threshold, during the mutual discharge of the first battery and the second battery, the charging device is controlled to charge the first battery and the second battery based on a second current, wherein the first current is greater than the second current, and the first current is less than a discharge current from the first battery to the second battery, and less than a discharge current from the second battery to the first battery.

8. The method according to any one of claims 1 to 7, characterized in that In the case where the two batteries are respectively a first battery and a second battery, the first module includes a switch circuit and a first energy storage circuit, the negative electrode of the first battery is connected to the positive electrode of the second battery, the positive electrode of the first battery is connected to the first end of the switch circuit, the negative electrode of the second battery is connected to the second end of the switch circuit, the switch circuit is also connected to the first end of the first energy storage circuit, the second end of the first energy storage circuit is connected to the midpoint of the first battery and the second battery, and controlling the first module to make the first battery and the second battery discharge each other includes: The switching circuit is used to perform at least one step of discharging the first battery from the first energy storage circuit and discharging the first energy storage circuit from the second battery, so that the first battery discharges from the second battery, and The steps of discharging the second battery to the first energy storage circuit and discharging the first energy storage circuit to the first battery are performed at least once through the switch circuit, so that the second battery discharges to the first battery.

9. The method according to claim 8, characterized in that A second energy storage circuit is further connected in parallel to both ends of the first battery and the second battery connected in series, and the method further includes: By means of the switch circuit, the first battery discharges to the first energy storage circuit and the second energy storage circuit discharges to the second battery at the same time, and the first energy storage circuit discharges to the second battery and the first battery discharges to the second energy storage circuit at the same time; and / or, Through the switch circuit, the second battery discharges to the first energy storage circuit and the second energy storage circuit discharges to the first battery at the same time, and the first energy storage circuit discharges to the first battery and the second battery discharges to the second energy storage circuit at the same time.

10. The method according to claim 8, characterized in that The switch circuit comprises: a bridge arm, comprising an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm is connected to the positive electrode of the first battery, the lower bridge arm is connected to the negative electrode of the second battery, and the first end of the first energy storage circuit is connected between the upper bridge arm and the lower bridge arm; The step of performing at least one of discharging the first battery to the first energy storage circuit and discharging the first energy storage circuit to the second battery through the switch circuit comprises: alternately performing the first step and the second step in sequence, The step of performing at least one of the second battery discharging to the first energy storage circuit and the first energy storage circuit discharging to the first battery through the switch circuit comprises: performing the second step and the first step alternately in sequence; wherein, The first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; The second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

11. A battery charging control circuit, characterized in that: The number of the batteries is two, the two batteries are connected in series, and the two batteries are connected in series to an external charging device, and the charging control circuit includes: A first module, connected to the battery; A controller is connected to the charging device for communication, and the controller is configured to: Control the charging device to charge the battery, and control the battery to be in N first charging stages in sequence according to the state of charge of the battery, where N is an integer greater than 1: wherein, The SOC of the battery in the n+1th first charging stage is greater than the SOC of the nth first charging stage, n is an integer, 1≤n≤N-1, each of the first charging stages includes: a constant current charging stage and a pulse charging stage, the constant current charging current corresponding to the n+1th first charging stage is less than the constant current charging current corresponding to the nth first charging stage, and the pulse charging stage includes: controlling the first module to make the two batteries discharge each other.

12. The battery charging control circuit according to claim 11, characterized in that: The controller is further configured to: control the constant current charging stage to be executed before the pulse charging stage.

13. The battery charging control circuit according to claim 11, characterized in that: The controller is also configured to: Obtaining the temperature of the battery during charging; In response to a temperature of the battery being greater than or equal to a first threshold, controlling the battery to be in N first charging stages in sequence according to a state of charge of the battery; In response to the temperature of the battery being less than the first threshold and the SOC of the battery being greater than a first SOC threshold, the battery is controlled to be in a heating stage, in which a pulse current is used to heat the battery.

14. The battery charging control circuit according to claim 11, characterized in that: The two batteries are respectively a first battery and a second battery, and the controller is further configured as follows: In the first charging stage, during the period when the first battery and the second battery discharge each other, the charging device is controlled to charge the first battery and the second battery, and the charging current of the charging device to the first battery and the second battery is smaller than the discharge current of the first battery to the second battery, and smaller than the discharge current of the second battery to the first battery.

15. The battery charging control circuit according to claim 11, characterized in that: The two batteries are respectively a first battery and a second battery, and the controller is further configured as follows: Acquire temperatures of the first battery and the second battery during charging; In response to the temperature of the first battery and the second battery being greater than or equal to a first threshold, controlling the first battery and the second battery to be in N first charging stages in sequence according to the charge states of the first battery and the second battery; In response to the temperature of either the first battery or the second battery being less than the first threshold, and the SOC of the first battery or the second battery being greater than a first SOC threshold, controlling the first battery or the second battery to be in a heating stage, the heating stage comprising: The first module is controlled to make the first battery and the second battery discharge each other.

16. The battery charging control circuit according to claim 15, characterized in that: The controller is also configured to: In the heating stage, during the period when the first battery and the second battery discharge each other, the charging device is controlled to charge the first battery and the second battery, and the charging current of the charging device to the first battery and the second battery is smaller than the discharge current of the first battery to the second battery, and smaller than the discharge current of the second battery to the first battery.

17. The battery charging control circuit according to claim 16, characterized in that: The controller is also configured to: During the heating phase, In response to a temperature of either the first battery or the second battery being less than a first threshold and greater than or equal to a second threshold, during a period in which the first battery and the second battery discharge each other, controlling the charging device to charge the first battery and the second battery based on a first current, the second threshold being less than the first threshold; In response to the temperature of either the first battery or the second battery being less than the second threshold, during the mutual discharge of the first battery and the second battery, the charging device is controlled to charge the first battery and the second battery based on a second current, wherein the first current is greater than the second current, and the first current is less than a discharge current from the first battery to the second battery, and less than a discharge current from the second battery to the first battery.

18. The battery charging control circuit according to any one of claims 11 to 17, characterized in that: When the two batteries are respectively a first battery and a second battery, the negative electrode of the first battery is connected to the positive electrode of the second battery, and the first module includes: a switch circuit, wherein the positive electrode of the first battery is connected to a first end of the switch circuit, and the negative electrode of the second battery is connected to a second end of the switch circuit; a first energy storage circuit, wherein a first end of the first energy storage circuit is connected to the switch circuit, and a second end of the first energy storage circuit is connected to a midpoint of the first battery and the second battery; The controller is configured to: The switching circuit is used to perform at least one step of discharging the first battery from the first energy storage circuit and discharging the first energy storage circuit from the second battery, so that the first battery discharges from the second battery, and The steps of discharging the second battery to the first energy storage circuit and discharging the first energy storage circuit to the first battery are performed at least once through the switch circuit, so that the second battery discharges to the first battery.

19. The battery charging control circuit according to claim 18, characterized in that: The battery charging control circuit also includes: a second energy storage circuit connected in parallel with the first battery and the second battery connected in series; The controller is also configured to: By means of the switch circuit, the first battery discharges to the first energy storage circuit and the second energy storage circuit discharges to the second battery at the same time, and the first energy storage circuit discharges to the second battery and the first battery discharges to the second energy storage circuit at the same time; and / or, Through the switch circuit, the second battery discharges to the first energy storage circuit and the second energy storage circuit discharges to the first battery at the same time, and the first energy storage circuit discharges to the first battery and the second battery discharges to the second energy storage circuit at the same time.

20. The battery charging control circuit according to claim 19, characterized in that: The first energy storage circuit includes at least one inductor, and the second energy storage circuit includes a capacitor.

21. The battery charging control circuit according to claim 18, characterized in that: The switch circuit comprises: A bridge arm, comprising an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm is connected to the positive electrode of the first battery, the lower bridge arm is connected to the negative electrode of the second battery, and the first end of the first energy storage circuit is connected between the upper bridge arm and the lower bridge arm; The controller is configured to: sequentially and alternately perform a first step and a second step to make the first battery discharge to the second battery, and sequentially and alternately perform the second step and the first step to make the second battery discharge to the first battery; in, The first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; The second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

22. A battery device, characterized in that: The battery charging control circuit comprises the battery charging control circuit as described in any one of claims 11-21.

23. An electrical device, characterized in that: It includes the battery device as described in claim 22, and the battery device supplies power to the electrical device.

24. An energy storage device, characterized in that: The energy storage device comprises a battery device as claimed in claim 22, wherein the battery device is used to store electrical energy.

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