Method for charging a battery, battery management system and charging and discharging device

Abstract

Embodiments of the present application provide a battery charging method, a battery management system and a charging and discharging device, which can guarantee the safety performance of the battery. The battery charging method comprises the following steps: a battery management system BMS acquires a first charging current and sends the first charging current to a charging and discharging device, so that the charging and discharging device charges the battery based on the first charging current; if a first cumulative charging amount of the battery is greater than or equal to a first cumulative charging amount threshold and a voltage of a battery cell of the battery does not exceed a full charging voltage of the battery cell, the BMS acquires a first discharging current and sends the first discharging current to the charging and discharging device, so that the charging and discharging device controls the battery to discharge based on the first discharging current; if a first cumulative discharging amount of the battery is greater than or equal to a first cumulative discharging amount threshold, the BMS acquires a second charging current and sends the second charging current to the charging and discharging device, so that the charging and discharging device charges the battery based on the second charging current.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a method for charging a battery, a battery management system, and a charging and discharging device. Background Technology

[0002] With the development of the times, electric vehicles have huge market prospects due to their advantages such as high environmental friendliness, low noise, and low operating costs. They can also effectively promote energy conservation and emission reduction, which is beneficial to social development and progress.

[0003] For electric vehicles and related fields, battery technology is a crucial factor in their development, especially battery safety, which affects the development and application of battery-related products and public acceptance of electric vehicles. Therefore, ensuring battery safety is a technical problem that needs to be solved. Summary of the Invention

[0004] This application provides a battery charging method, a battery management system, and a charging and discharging device, which can ensure the safety performance of the battery.

[0005] In a first aspect, a method for charging a battery is provided, comprising: a battery management system (BMS) acquiring a first charging current and sending the first charging current to a charging and discharging device, so that the charging and discharging device charges the battery based on the first charging current; if a first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell, the BMS acquiring a first discharge current and sending the first discharge current to the charging and discharging device, so that the charging and discharging device controls the battery to discharge based on the first discharge current; if a first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS acquiring a second charging current and sending the second charging current to the charging and discharging device, so that the charging and discharging device charges the battery based on the second charging current.

[0006] The technical solution of this application provides a charging method that can be implemented between a charging and discharging device and a BMS. During the charging process of the battery, the charging and discharging device can charge and discharge the battery based on the first charging current and the first discharging current sent by the BMS, thereby avoiding problems such as heat generation and lithium ion accumulation caused by continuous charging, and thus avoiding battery safety problems caused by heat generation and lithium ion accumulation, such as battery combustion or explosion, and ensuring the safety performance of the battery.

[0007] In one possible implementation, the method further includes: if the second cumulative charge of the battery is greater than or equal to the second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS acquires the second discharge current and sends the second discharge current to the charging and discharging device so that the charging and discharging device controls the battery discharge based on the second discharge current.

[0008] The technical solution implemented in this way, through information interaction between the BMS and the charging / discharging device, completes the charging, discharging, and recharging of the battery, and then allows for further discharging. According to this method, embodiments of this application can further provide a multi-cycle charging / discharging method, where the charging and discharging processes are performed sequentially, achieving gradual charging of the battery while ensuring battery performance.

[0009] In one possible implementation, the method further includes: if the voltage of a single battery cell exceeds the full charge voltage of the single battery cell, the BMS sends a charging stop command to the charging and discharging device, the charging stop command being used to instruct the charging and discharging device to stop charging the battery.

[0010] In one possible implementation, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0011] With this technical solution, while ensuring the safety performance of the battery, the charging rate of the first charging current and / or the second charging current is between 2C and 10C, which can achieve high-current fast charging, thereby increasing the amount of battery charge during a single charge and achieving the purpose of fast charging.

[0012] In addition, the charging current is limited by the accumulation of lithium ions at the negative electrode during continuous charging, so it is impossible to use a continuous large current to achieve fast charging of the battery. However, the technical solution of this application uses a large current to charge the battery, and discharges the battery after a large current charge to release the lithium ions accumulated at the negative electrode of the battery during the charging process. Then, the battery can be charged again with a large current to achieve fast charging of the battery.

[0013] In one possible implementation, the discharge rate of the first discharge current ranges from 0.1C to 1C.

[0014] The technical solution of this implementation method allows the discharge rate of the first discharge current to be between 0.1C and 1C, so as to achieve small current discharge. The aim is to release the lithium ions accumulated on the negative electrode of the battery through small current discharge, without causing excessive loss of the charged power in the battery.

[0015] In one possible implementation, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

[0016] By setting the ratio of the cumulative discharge threshold during the discharge process to the cumulative charge threshold during the charging process, the charging amount of the battery during the charging process and the discharging amount of the battery during the discharging process can be better controlled, resulting in a smaller discharge amount and preventing excessive loss of the charged amount in the battery.

[0017] In one possible implementation, the BMS acquiring the first charging current includes: the BMS acquiring the battery's state parameters and determining the first charging current based on the state parameters; and / or, the BMS acquiring the first discharging current includes: the BMS acquiring the battery's state parameters and determining the first discharging current based on the state parameters; and / or, the BMS acquiring the second charging current includes: the BMS acquiring the battery's state parameters and determining the second charging current based on the state parameters; wherein the battery's state parameters include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge, and battery health status.

[0018] With this technical solution, when at least one of the first charging current, the second charging current, and the first discharging current is a current determined according to the battery's state parameters, it can better adapt to the current state parameters of the battery, improve the charging efficiency and / or discharging efficiency of the battery, and will not cause damage to the battery.

[0019] In one possible implementation, the BMS acquiring a first charging current and sending the first charging current to the charging / discharging device includes: the BMS periodically acquiring the first charging current and periodically sending the first charging current to the charging / discharging device; and / or, the BMS acquiring a first discharging current and sending the first discharging current to the charging / discharging device includes: the BMS periodically acquiring the first discharging current and periodically sending the first discharging current to the charging / discharging device; and / or, the BMS acquiring a second charging current and sending the second charging current to the charging / discharging device includes: the BMS periodically acquiring the second charging current and periodically sending the second charging current to the charging / discharging device.

[0020] In this implementation, during a single charge and / or discharge cycle, the charging and / or discharging current is periodically sent by the BMS. On the one hand, this implementation allows for periodic adjustment of the charging and / or discharging current to improve charging and discharging efficiency. On the other hand, the periodically sent charging and / or discharging current indicates that the BMS and battery are in normal condition, facilitating the charging and discharging device to continue charging the battery or control battery discharge, thereby ensuring battery safety.

[0021] In one possible implementation, the method further includes: the BMS acquiring a first charging voltage and sending the first charging voltage to the charging / discharging device, wherein the first charging current and the first charging voltage are carried in a first battery charging request (BCL) message; and / or, the method further includes: the BMS acquiring a first discharging voltage and sending the first discharging voltage to the charging / discharging device, wherein the first discharging current and the first discharging voltage are carried in a second BCL message; and / or, the method further includes: the BMS acquiring a second charging voltage and sending the second charging voltage to the charging / discharging device, wherein the second charging current and the second charging voltage are carried in a third BCL message.

[0022] In this implementation, the communication between the BMS and the charging / discharging device is compatible with the existing communication protocol between the charger and the BMS. Therefore, the communication between the BMS and the charging / discharging device is easy to implement and has good application prospects.

[0023] Secondly, a method for charging a battery is provided, comprising: a charging and discharging device receiving a first charging current sent by a battery management system (BMS) and charging the battery based on the first charging current; the charging and discharging device receiving a first discharging current sent by the BMS and controlling the battery to discharge based on the first discharging current, wherein the first discharging current is the discharging current sent by the BMS when the first cumulative charge of the battery is greater than or equal to a first cumulative charge threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell; and the charging and discharging device receiving a second charging current sent by the BMS and charging the battery based on the second charging current, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge of the battery is greater than or equal to the first cumulative discharge threshold.

[0024] In one possible implementation, the method further includes: the charging and discharging device receiving a second discharge current sent by the BMS, and controlling the battery to discharge based on the second discharge current, wherein the second discharge current is the discharge current sent by the BMS when the second cumulative charge of the battery is greater than or equal to a second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell.

[0025] In one possible implementation, the method further includes: the charging / discharging device receiving a charging stop command sent by the BMS and stopping charging the battery, wherein the charging stop command is a command sent by the BMS when the voltage of a single battery cell exceeds the full charge voltage of the single battery cell.

[0026] In one possible implementation, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0027] In one possible implementation, the discharge rate of the first discharge current ranges from 0.1C to 1C.

[0028] In one possible implementation, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

[0029] In one possible implementation, at least one of the first charging current, the first discharging current, and the second charging current is determined by the BMS based on the battery's state parameters; wherein the battery's state parameters include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge, and battery state of health.

[0030] In one possible implementation, the charging and discharging device receiving a first charging current sent by the BMS includes: the charging and discharging device periodically receiving the first charging current sent by the BMS; and / or, the charging and discharging device receiving a first discharging current sent by the BMS includes: the charging and discharging device periodically receiving the first discharging current sent by the BMS; and / or, the charging and discharging device receiving a second charging current sent by the BMS includes: the charging and discharging device periodically receiving the second charging current sent by the BMS.

[0031] In one possible implementation, the method further includes: the charging / discharging device receiving a first charging voltage sent by the BMS, wherein the first charging voltage and a first charging current are carried in a first battery charging demand (BCL) message; and / or, the method further includes: the charging / discharging device receiving a first discharging voltage sent by the BMS, wherein the first discharging voltage and a first discharging current are carried in a second BCL message; and / or, the method further includes: the charging / discharging device receiving a second charging voltage sent by the BMS, wherein the second charging voltage and a second charging current are carried in a third BCL message.

[0032] Thirdly, a battery management system (BMS) is provided, comprising: an acquisition unit for acquiring a first charging current; a transmission unit for transmitting the first charging current to a charging / discharging device to charge the battery based on the first charging current; a processing unit for determining that when a first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell, the acquisition unit is further configured to acquire a first discharge current; the transmission unit is further configured to transmit the first discharge current to the charging / discharging device to control the battery to discharge based on the first discharge current; the processing unit is further configured to determine that when a first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the acquisition unit is further configured to acquire a second charging current; the transmission unit is further configured to transmit the second charging current to the charging / discharging device to charge the battery based on the second charging current.

[0033] Fourthly, a charging and discharging device is provided, comprising: a receiving unit for receiving a first charging current sent by a battery management system (BMS); a processing unit for charging a battery based on the first charging current; the receiving unit is further configured to receive a first discharging current sent by the BMS, and the processing unit is further configured to control the battery to discharge based on the first discharging current, wherein the first discharging current is the discharging current sent by the BMS when the first cumulative charge of the battery is greater than or equal to a first cumulative charge threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell; the receiving unit is further configured to receive a second charging current sent by the BMS, and the processing unit is further configured to charge the battery based on the second charging current, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge of the battery is greater than or equal to the first cumulative discharge threshold.

[0034] Fifthly, a charging and discharging device is provided, comprising: a control unit and a power conversion unit, the control unit being configured to: receive a first charging current sent by a battery management system (BMS), and control the power conversion unit to charge a battery based on the first charging current; receive a first discharging current sent by the BMS, and control the power conversion unit to discharge the battery based on the first discharging current, wherein the first discharging current is a discharging current sent by the BMS when a first cumulative charge of the battery is greater than or equal to a first cumulative charge threshold and the voltage of a single cell of the battery does not exceed the full charge voltage of the single cell; and receive a second charging current sent by the BMS, and control the power conversion unit to charge the battery based on the second charging current, wherein the second charging current is a charging current sent by the BMS when a first cumulative discharge of the battery is greater than or equal to the first cumulative discharge threshold.

[0035] In one possible implementation, the power conversion unit is connected to an AC power source and a battery, wherein the power conversion unit includes an AC / DC converter and a DC / DC converter; the control unit is used to control the AC / DC converter and the DC / DC converter to charge the battery through the AC power source based on a first charging current, and the control unit is used to control the AC / DC converter and the DC / DC converter to charge the battery through the AC power source based on a second charging current.

[0036] In one possible implementation, the AC / DC converter is a bidirectional AC / DC converter, the DC / DC converter is a bidirectional DC / DC converter, and the control unit is used to control the bidirectional AC / DC converter and the bidirectional DC / DC converter based on a first discharge current to discharge the battery into the AC power source.

[0037] In one possible implementation, the control unit is further configured to: receive a second discharge current sent by the BMS, and control the bidirectional AC / DC converter and the bidirectional DC / DC converter based on the second discharge current, so that the battery discharges into the AC power supply, wherein the second discharge current is the discharge current sent by the BMS when the second cumulative charge of the battery is greater than or equal to a second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell.

[0038] In one possible implementation, the control unit is further configured to: receive a charging stop command sent by the BMS, and control the bidirectional AC / DC converter and the bidirectional DC / DC converter to stop charging the battery based on the charging stop command, wherein the charging stop command is a command sent by the BMS when the voltage of a battery cell exceeds the full charge voltage of the battery cell.

[0039] In one possible implementation, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0040] In one possible implementation, the discharge rate of the first discharge current ranges from 0.1C to 1C.

[0041] In one possible implementation, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

[0042] In one possible implementation, at least one of the first charging current, the first discharging current, and the second charging current is determined by the BMS based on the battery's state parameters; wherein the battery's state parameters include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge, and battery state of health.

[0043] In one possible implementation, the control unit is configured to periodically receive a first charging current sent by the BMS; and / or, the control unit is configured to periodically receive a first discharging current sent by the BMS; and / or, the control unit is configured to periodically receive a second charging current sent by the BMS.

[0044] Optionally, the control unit is further configured to receive a first charging voltage sent by the BMS, wherein the first charging voltage and the first charging current are carried in a first battery charging demand (BCL) message; and / or, the control unit is further configured to receive a first discharging voltage sent by the BMS, wherein the first discharging voltage and the first discharging current are carried in a second BCL message; and / or, the control unit is further configured to receive a second charging voltage sent by the BMS, wherein the second charging voltage and the second charging current are carried in a third BCL message.

[0045] In a sixth aspect, a battery management system (BMS) is provided, including a processor and a memory for storing a computer program, and the processor for calling the computer program to execute the methods described in the first aspect and any possible implementation thereof.

[0046] In a seventh aspect, a charging and discharging apparatus is provided, including a processor and a memory for storing a computer program, the processor for invoking the computer program to execute a method as described in either the second aspect or any of the possible implementations of the second aspect above. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0048] Figure 1 This is an architectural diagram of a charging system applicable to one embodiment of this application;

[0049] Figure 2 This is a schematic flowchart of a battery charging method provided in an embodiment of this application;

[0050] Figure 3 This is a schematic flowchart of another battery charging method provided in an embodiment of this application;

[0051] Figure 4 This is a schematic waveform diagram of the charging current and discharging current of the battery provided in the embodiments of this application;

[0052] Figure 5 This is a schematic flowchart of another battery charging method provided in an embodiment of this application;

[0053] Figure 6 This is a schematic flowchart of another battery charging method provided in an embodiment of this application;

[0054] Figure 7 This is a schematic flowchart of another battery charging method provided in an embodiment of this application;

[0055] Figure 8 This is a schematic flowchart of another battery charging method provided in an embodiment of this application;

[0056] Figure 9 This is a schematic structural block diagram of a battery management system (BMS) provided in an embodiment of this application;

[0057] Figure 10This is a schematic structural block diagram of a charging and discharging device provided in an embodiment of this application;

[0058] Figure 11 This is a schematic structural block diagram of another charging and discharging device provided in the embodiments of this application;

[0059] Figure 12 This is a schematic structural block diagram of the power conversion unit in the charging and discharging device provided in the embodiments of this application;

[0060] Figure 13 This is a schematic structural block diagram of an electronic device according to an embodiment of this application. Detailed Implementation

[0061] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0062] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0063] In the field of new energy, power batteries serve as the primary power source for electrical devices (such as vehicles, ships, or spacecraft), while energy storage batteries serve as the charging source for these devices; the importance of both is self-evident. As an example, and not a limitation, in some applications, power batteries can refer to the batteries within electrical devices, and energy storage batteries can refer to the batteries within charging devices. For ease of description, both power batteries and energy storage batteries will be referred to as batteries in the following text.

[0064] Currently, most batteries on the market are rechargeable rechargeable batteries, the most common being lithium batteries, such as lithium-ion batteries or lithium-ion polymer batteries. During charging, batteries are generally charged continuously. However, continuous charging can cause lithium plating and overheating. These phenomena not only degrade battery performance and significantly shorten cycle life, but also limit the battery's fast-charging capacity and may even lead to catastrophic consequences such as combustion and explosion, causing serious safety problems.

[0065] To ensure battery safety, this application proposes a new battery charging method and charging system.

[0066] Figure 1 An architecture diagram of a charging system applicable to an embodiment of this application is shown.

[0067] like Figure 1 As shown, the charging system 100 may include a charging and discharging device 110 and a battery system 120. Optionally, the battery system 120 may be a battery system in an electric vehicle (including pure electric vehicles and plug-in hybrid electric vehicles) or a battery system in other application scenarios.

[0068] Optionally, the battery system 120 may include at least one battery pack, which can be collectively referred to as battery 121. In terms of battery type, battery 121 can be any type of battery, including but not limited to: lithium-ion batteries, lithium metal batteries, lithium-sulfur batteries, lead-acid batteries, nickel-metal hydride batteries, or lithium-air batteries, etc. In terms of battery size, battery 121 in this embodiment can be a cell, a battery module, or a battery pack. A battery module or battery pack can be formed by connecting multiple batteries in series and parallel. In this embodiment, the specific type and size of battery 121 are not specifically limited.

[0069] In addition, to intelligently manage and maintain the battery 121, prevent overcharging and over-discharging, and extend the battery's lifespan, the battery system 120 generally includes a battery management system (BMS) 122 for monitoring the status of the battery 121. Optionally, the BMS 122 can be integrated with the battery 121 in the same device, or the BMS 122 can be a separate device located outside the battery 121.

[0070] Specifically, the charging and discharging device 110 is a device for replenishing electrical energy to the battery 121 in the battery system 120 and / or controlling the discharge of the battery 121.

[0071] Optionally, the charging and discharging device 110 in this application embodiment can be a regular charging pile, a supercharging pile, a charging pile supporting vehicle-to-grid (V2G) mode, or a charging and discharging device / equipment that can charge and / or discharge a battery, etc. This application embodiment does not limit the specific type or application scenario of the charging and discharging device 110.

[0072] Optionally, such as Figure 1As shown, the charging and discharging device 110 can be connected to the battery 121 via the wire 130 and to the BMS 122 via the communication line 140, wherein the communication line 140 is used to realize information interaction between the charging and discharging device 110 and the BMS.

[0073] As an example, the communication line 140 may include, but is not limited to, a controller area network (CAN) communication bus or a daisy chain communication bus.

[0074] Optionally, in addition to communicating with the BMS 122 via the communication line 140, the charging / discharging device 110 can also communicate with the BMS 122 via a wireless network. This application embodiment does not specifically limit the wired or wireless communication type between the charging / discharging device and the BMS 122.

[0075] Figure 2 A schematic flowchart of a battery charging method 200 according to an embodiment of this application is shown. Optionally, the method 200 of this application embodiment can be applied to the above-described... Figure 1 The charging / discharging device 110 and battery system 120 are shown.

[0076] like Figure 2 As shown, the battery charging method 200 may include the following steps.

[0077] Step 210: The Battery Management System (BMS) acquires the first charging current.

[0078] Step 220: The BMS sends the first charging current to the charging and discharging device.

[0079] Step 230: The charging and discharging device charges the battery based on the first charging current.

[0080] Step 240: If the first cumulative charge of the battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS obtains the first discharge current.

[0081] Step 250: The BMS sends the first discharge current to the charging and discharging device.

[0082] Step 260: The charging and discharging device controls the battery to discharge based on the first discharge current.

[0083] This application provides a charging method that can be implemented between a charging / discharging device and a battery management system (BMS). During battery charging, the charging / discharging device can charge and discharge the battery based on a first charging current and a first discharging current sent by the BMS, avoiding continuous charging and thus preventing problems such as overheating and lithium-ion accumulation caused by continuous charging. Overheating causes the battery temperature to rise, and the crystals formed by lithium-ion accumulation may puncture the battery, causing electrolyte leakage and short circuits. Both overheating and short circuits can lead to battery safety issues, such as battery combustion or explosion. Therefore, the technical solution of this application, where the charging / discharging device charges and discharges the battery based on the first charging current and the first discharging current sent by the BMS, can ensure battery safety. Furthermore, continuous lithium-ion accumulation during charging can cause lithium plating, affecting battery lifespan and charging capacity. Therefore, the technical solution of this application also ensures battery lifespan and charging capacity.

[0084] Specifically, in steps 210 to 230, the BMS can first enter the charging mode to control the charging and discharging device to charge the battery. First, the BMS obtains the first charging current. After the BMS sends the first charging current to the charging and discharging device, the charging and discharging device charges the battery based on the received first charging current.

[0085] Optionally, the BMS may obtain the first charging current from its own functional units (e.g., storage units or processing units), or the BMS may obtain the first charging current from other devices. In some embodiments, the first charging current may be a preset current, which may be a fixed value or may vary over time according to a preset method. Alternatively, in other embodiments, the first charging current may be a current determined based on the battery's state parameters, which varies with changes in the battery's state parameters.

[0086] Optionally, the charging and discharging device can be connected to a power source, which can be an AC power source and / or a DC power source. After receiving information about the first charging current, the charging and discharging device charges the battery based on the first charging current through the AC power source and / or the DC power source.

[0087] Furthermore, during the charging and discharging process of the battery based on the first charging current, the BMS can obtain the first cumulative charge amount of the battery and determine whether the first cumulative charge amount is greater than or equal to the first cumulative charge amount threshold. If the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS obtains the first discharge current.

[0088] Specifically, as mentioned above Figure 1As described in the battery description, a battery may include one or more individual battery cells. The BMS can monitor whether the battery has reached a fully charged state by monitoring the voltage of one or more individual battery cells. Optionally, if the battery includes multiple individual battery cells, the voltages of these cells may differ. In this case, the battery can be fully charged by determining whether the maximum voltage of a single battery cell exceeds its full-charge voltage. Alternatively, in other methods, in addition to the maximum voltage of the individual battery cells, other voltages of the individual battery cells can be used to determine whether the battery has reached a fully charged state.

[0089] If the voltage of a single battery cell does not exceed the full charge voltage of that cell, meaning the battery is not fully charged, and if the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold, the BMS obtains the first discharge current, which means that the battery switches from charging mode to discharging mode.

[0090] Optionally, the first cumulative charging amount can be either a first cumulative charging capacity or a first cumulative charging quantity. Correspondingly, if the first cumulative charging amount is the first cumulative charging capacity, then the first cumulative charging amount threshold is the first cumulative charging capacity threshold; if the first cumulative charging amount is the first cumulative charging quantity, then the first cumulative charging amount threshold is the first cumulative charging quantity threshold.

[0091] In some implementations, the aforementioned first cumulative charge threshold can be a preset threshold, which can be a fixed threshold or can change over time in a preset manner.

[0092] In other embodiments, the first cumulative charge threshold can also be determined based on the battery's state parameters. That is, when the battery's state parameters change, the first cumulative charge threshold also changes. Through this embodiment, the first cumulative charge threshold can better adapt to the current state parameters of the battery, so as to better control the current charging process, improve the charging efficiency of the battery, and not cause damage to the battery.

[0093] Furthermore, in steps 240 to 260, the BMS acquires the first discharge current and sends the first discharge current to the charging and discharging device, which controls the battery to discharge based on the received first discharge current.

[0094] Optionally, the BMS can obtain the first discharge current from its own functional units (e.g., storage units or processing units), or it can obtain the first discharge current from other devices. In some embodiments, the first discharge current can be a preset current, which can be a fixed value or can vary over time according to a preset method. Alternatively, in other embodiments, the first discharge current can be a current determined based on the battery's state parameters, which varies with changes in the battery's state parameters. In some embodiments, during discharge mode or discharge phase, the battery's electricity can be transferred to an energy storage device and / or the power grid, which is beneficial for the recycling of electrical energy. The energy storage device can be located within or outside the charging and discharging device, designed to receive the battery's discharge current. This application embodiment does not limit the specific configuration of the energy storage device. Optionally, during discharge mode, the battery's charge can also be consumed in other ways. This application embodiment does not limit the specific way of consuming electrical energy.

[0095] Furthermore, during the process of the charging and discharging device controlling the battery discharge, the BMS can obtain the first cumulative discharge amount of the battery during the discharge process and determine whether the first cumulative discharge amount is greater than or equal to the first cumulative discharge amount threshold.

[0096] Optionally, the first cumulative discharge amount can be either a first cumulative discharge capacity or a first cumulative discharge quantity. Correspondingly, if the first cumulative discharge amount is the first cumulative discharge capacity, then the first cumulative discharge amount threshold is the first cumulative discharge capacity threshold; if the first cumulative discharge amount is the first cumulative discharge quantity, then the first cumulative discharge threshold is the first cumulative discharge quantity threshold.

[0097] In some implementations, the aforementioned first cumulative discharge threshold can be a preset threshold, which can be a fixed threshold or can change over time in a preset manner.

[0098] In other embodiments, the first cumulative discharge threshold can also be determined based on the battery's state parameters. That is, when the battery's state parameters change, the first cumulative discharge threshold also changes. Through this embodiment, the first cumulative discharge threshold can better adapt to the current state parameters of the battery, so as to better control the current discharge process, improve the battery's discharge efficiency, and not cause damage to the battery.

[0099] When the first cumulative discharge amount is greater than or equal to the first cumulative discharge amount threshold, the charging and discharging device controls the battery to stop discharging.

[0100] Through the above process, the charging and discharging device charges and discharges the battery based on the first charging current and the first discharging current sent by the BMS, thereby avoiding problems such as overheating and lithium-ion accumulation caused by continuous charging. This prevents battery safety issues such as combustion or explosion caused by overheating and lithium-ion accumulation, ensuring battery safety performance. Furthermore, by charging the battery to a first cumulative charge level using the first charging current and then discharging it to a first cumulative discharge level using the first discharging current, lithium ions accumulated at the negative electrode during charging can be released, preventing lithium plating problems that occur during continuous charging, thus improving battery life and charging capacity.

[0101] For battery charging, after one charge and one discharge cycle, the battery can be charged a second time to continue charging.

[0102] Optionally, such as Figure 2 As shown, the battery charging method 200 in this embodiment may further include the following steps.

[0103] Step 270: If the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS obtains the second charging current.

[0104] Step 280: The BMS sends a second charging current to the charging and discharging device.

[0105] Step 290: The charging and discharging device charges the battery based on the second charging current.

[0106] Specifically, in steps 270 to 290 above, when the BMS determines that the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS acquires the second charging current and sends the second charging current to the charging and discharging device. The charging and discharging device continues to charge the battery based on the received second charging current, that is, for the battery, it re-enters the charging mode from the discharging mode. Optionally, other related technical solutions for steps 270 to 290 can be found in the relevant descriptions of steps 210 to 230 above, and will not be elaborated further here.

[0107] Understandably, in the above-described embodiments, charging and discharging the battery requires not only the current information but also the voltage information. For example, in steps 210 to 230: the BMS acquires a first charging current and a first charging voltage, and sends the first charging current and the first charging voltage to the charging and discharging device, which charges the battery based on the first charging current and the first charging voltage; in steps 240 to 260, the BMS acquires a first discharging current and a first discharging voltage, and sends the first discharging current and the first discharging voltage to the charging and discharging device, which discharges the battery based on the first discharging current and the first discharging voltage. Subsequent charging and discharging processes are similar to the above-described charging and discharging processes and will not be described in detail here.

[0108] Figure 3 A schematic flowchart of another battery charging method 300 provided in an embodiment of this application is shown.

[0109] like Figure 3 As shown, in addition to steps 210 to 290 described above, the battery charging method 300 may further include the following steps.

[0110] Step 310: If the second cumulative charge of the battery is greater than or equal to the second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS obtains the second discharge current.

[0111] Step 320: The BMS sends a second discharge current to the charging and discharging device.

[0112] Step 330: The charging and discharging device controls the battery discharge based on the second discharge current.

[0113] In this embodiment, the charging, discharging, recharging, and re-discharging of the battery are completed through information interaction between the BMS and the charging / discharging device. Following this approach, this embodiment can further provide a multi-cycle charging / discharging method, where the charging and discharging processes are performed sequentially, achieving gradual charging of the battery while ensuring its safety performance.

[0114] Specifically, in step 310, during the process of the charging and discharging device charging the battery based on the second charging current, the BMS can obtain the second cumulative charge amount of the battery and determine whether the second cumulative charge amount is greater than or equal to the second cumulative charge amount threshold.

[0115] Optionally, the second cumulative charge amount may be only the amount of charge the charging and discharging device performs on the battery based on the second charging current, or the second cumulative charge amount may also be the current total charge amount of the battery. For example, the current total charge amount of the battery = the charge amount based on the first charging current + the charge amount based on the second charging current - the discharge amount based on the first discharging current. Correspondingly, the second cumulative charge amount threshold may also be a charge amount threshold based on a single charge, or the second cumulative charge amount threshold may also be a charge amount threshold based on the total charge amount.

[0116] Similar to the first cumulative charging amount and the first cumulative charging amount threshold described above, in this embodiment, the second cumulative charging amount can be either the second cumulative charging capacity or the second cumulative charging quantity. Correspondingly, if the second cumulative charging amount is the second cumulative charging capacity, then the first cumulative charging amount threshold is the second cumulative charging capacity threshold; if the second cumulative charging amount is the second cumulative charging quantity, then the second cumulative charging amount threshold is the second cumulative charging quantity threshold.

[0117] Optionally, in some embodiments, the second cumulative charge threshold can be a preset threshold, which can be a fixed threshold or can change over time in a preset manner.

[0118] In other embodiments, the second cumulative charge threshold can also be determined based on the battery's state parameters, that is, when the battery's state parameters change, the second cumulative charge threshold also changes accordingly.

[0119] Further, in step 310, when the second accumulated charge is greater than or equal to the second accumulated charge threshold, and the voltage of a single battery cell does not exceed the full charge voltage of the single cell, the BMS acquires the second discharge current. In steps 320 to 330, the BMS sends this second discharge current to the charging / discharging device, and the charging / discharging device controls the battery discharge based on the received second discharge current.

[0120] Specifically, other related technical solutions in the above steps can be found in the relevant descriptions of steps 240 to 260 above, which will not be elaborated on here.

[0121] As an example, Figure 4 A schematic waveform diagram of the charging current and discharging current of a battery provided in an embodiment of this application is shown.

[0122] like Figure 4As shown, from time period t1 to t2, the charging and discharging device charges the battery based on a first charging current, charging until the battery's first cumulative charge amount is greater than or equal to a first cumulative charge amount threshold and the voltage of a single battery cell does not exceed the full charge voltage of that single cell. From time period t2 to t3, the charging and discharging device controls the battery to discharge based on a first discharging current, discharging until the battery's first cumulative discharge amount is greater than or equal to a first cumulative discharge amount threshold. Optionally, the duration of the first discharging current may be shorter than the duration of the first charging current. From time period t3 to t4, the charging and discharging device continues to charge the battery based on a second charging current, charging until the battery's second cumulative charge amount is greater than or equal to a second cumulative charge amount threshold and the voltage of a single battery cell does not exceed the full charge voltage of that single cell. From time period t4 to t5, the charging and discharging device controls the battery to discharge based on a second discharging current, discharging until the battery's second cumulative discharge amount is greater than or equal to a second cumulative discharge amount threshold. Optionally, the duration of the second charging current may be shorter than the duration of the first charging current. It is understood that the above charging and discharging process continues until the battery is fully charged.

[0123] It should be noted that, Figure 4 The waveforms of the first charging current, the second charging current, the first discharging current, and the second discharging current are only schematically shown. The first charging current can be as follows from t1 to t2: Figure 4 The constant current shown can also be a time-varying current; similarly, the second charging current, the first discharging current, and the second discharging current can be as follows: Figure 4 The current shown can be a constant current, or it can be a changing current that varies with time. Additionally, Figure 4 The schematic diagram shows that the first charging current and the second charging current are the same in magnitude, and the first discharging current and the second discharging current are the same in magnitude. However, the magnitudes of the first charging current and the second charging current may also be different, and the magnitudes of the first discharging current and the second discharging current may also be different. This application does not specifically limit this.

[0124] Figure 5 A schematic flowchart of another battery charging method 500 provided in an embodiment of this application is shown.

[0125] like Figure 5 As shown, in addition to steps 210 to 290 described above, the battery charging method 500 may further include the following steps.

[0126] Step 510: If the voltage of a single battery cell exceeds the full charge voltage of that cell, the BMS sends a charging stop command to the charging / discharging device.

[0127] Step 520: The charging / discharging device stops charging the battery.

[0128] Specifically, as described above, the BMS can monitor whether the battery has reached a fully charged state by monitoring the voltage of one or more individual battery cells. Optionally, in some embodiments, the full charge state can be determined by whether the maximum voltage of a single battery cell exceeds its full charge voltage. When the maximum voltage of a single battery cell exceeds its full charge voltage, it indicates that the battery has reached a fully charged state. At this time, the BMS sends a charging stop command to the charging and discharging device, which instructs the device to stop charging the battery.

[0129] Optionally, steps 510 and 520 can be performed during the battery charging phase. In other words, when the BMS enters the charging mode and the charging and discharging device receives the charging current sent by the BMS, during the charging process, the BMS can obtain the voltage of the battery cells to determine whether the battery has reached a fully charged state. Once the voltage of a battery cell exceeds the full charge voltage of the battery cell, the BMS sends a charging stop command to the charging and discharging device to stop charging the battery.

[0130] therefore, Figure 5 The steps 510 and 520 are shown only schematically after step 290, i.e. during the second charging process. It can be understood that steps 510 and 520 can also be performed during any one of the multiple charging and discharging processes.

[0131] Optionally, in the above method embodiments, since the charging and discharging device is used to charge, discharge and recharge the battery, safety problems caused by continuous charging can be prevented. Furthermore, the charging current in the above method can be a large current to increase the amount of battery charge during a single charge and achieve the purpose of fast charging.

[0132] In addition, the charging current is limited by the accumulation of lithium ions at the negative electrode during continuous charging, so it is impossible to use a continuous large current to achieve fast charging of the battery. However, the technical solution of this application uses a large current to charge the battery, and discharges the battery after a large current charge to release the lithium ions accumulated at the negative electrode of the battery during the charging process. Then, the battery can be charged again with a large current to achieve fast charging of the battery.

[0133] Specifically, in the above method, the first charging current and / or the second charging current can be a large current. In addition, after the charging and discharging device charges the battery based on the second charging current, the charging current in the subsequent charging process can also be a large current.

[0134] Optionally, in order to achieve high-current fast charging, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0135] Furthermore, in this embodiment, the discharge current is a small current, which aims to release the lithium ions accumulated on the negative electrode of the battery through the discharge of a small current, without causing excessive loss of the charge already in the battery.

[0136] Specifically, the first discharge current and / or the second discharge current in the above method can be small currents. In addition, after the charging and discharging device controls the battery discharge based on the second discharge current, the discharge current in the subsequent discharge process can also be small currents.

[0137] Optionally, in order to achieve low-current discharge, the charging rate of the first discharge current and / or the second discharge current is in the range of 0.1C to 1C.

[0138] Optionally, in the above method, in order to better control the amount of charge in the battery during charging and the amount of discharge in the battery during discharging, a cumulative discharge threshold and a ratio of the cumulative charge threshold during charging can be set so that the discharge amount is small and the amount of charge already charged in the battery is not lost too much.

[0139] As an example, in the above method, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%, and / or the ratio of the second cumulative discharge threshold to the second cumulative charge threshold is less than or equal to 10%.

[0140] In addition, after the charging and discharging device charges the battery and controls the battery discharge based on the second charging current and the second discharging current, the ratio of the cumulative discharge threshold to the cumulative charge threshold in the subsequent charging and discharging process can also be less than or equal to 10%.

[0141] It should be noted that the aforementioned 10% ratio can be adjusted according to changes in application scenarios and application requirements. This application does not limit the specific value of this ratio.

[0142] Optionally, in the above method embodiments, the first charging current and the second charging current obtained by the BMS can be the same or different. The first charging current and / or the second charging current can be a preset current, or the first charging current and / or the second charging current can be a current determined based on the battery's state parameters. When the battery's state parameters change, the first charging current and / or the second charging current can be different currents corresponding to different state parameters. The battery's state parameters include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge (SOC), and battery state of health (SOH), etc.

[0143] Similarly, the first discharge current and the second discharge current acquired by the BMS can be the same or different. The first discharge current and / or the second discharge current can be a preset current, or the first discharge current and / or the second discharge current can be a current determined according to the battery's state parameters.

[0144] If at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current is a current determined based on the battery's state parameters, it can better adapt to the current state parameters of the battery, improve the battery's charging efficiency and / or discharging efficiency, and will not cause damage to the battery.

[0145] In addition, after the charging and discharging device charges the battery and controls the battery to discharge based on the second charging current and the second discharging current, the charging current and / or discharging current in subsequent charging and discharging processes can also be preset currents, or they can be currents determined according to the battery's state parameters.

[0146] Figure 6 A schematic flowchart of another battery charging method 600 provided in an embodiment of this application is shown.

[0147] Based on the above Figure 2 Method 200 shown, such as Figure 6 As shown, step 210 above may include:

[0148] Step 610: The BMS acquires the battery's status parameters and determines the first charging current based on the status parameters.

[0149] Step 240 above may include:

[0150] Step 640: If the first cumulative charge of the battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS obtains the battery state parameters and determines the first discharge current based on the state parameters.

[0151] Step 270 above may include:

[0152] Step 670: If the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS obtains the battery's state parameters and determines the second charging current based on the state parameters.

[0153] In addition to the above, other steps of method 600 in the embodiments of this application can be found in the above text. Figure 2 The relevant descriptions of the embodiments shown will not be repeated here.

[0154] Specifically, in this embodiment, the first charging current, the first discharging current, and the second charging current are all currents determined based on the battery's state parameters. At different times, the BMS can acquire different state parameters of the battery and determine the current charging current and discharging current based on these state parameters.

[0155] Optionally, there are multiple ways to determine the charging and discharging currents based on the battery's state parameters. As an example, a mapping relationship between the battery's state parameters and the charging and discharging currents can be obtained. Based on this mapping relationship, the specific charging and discharging currents can be determined using the battery's state parameters. This mapping relationship can be obtained by fitting a large amount of experimental data, possessing high reliability and accuracy. Specifically, this mapping relationship can be a mapping table, mapping graph, or mapping formula, etc. Furthermore, in other examples, a dedicated neural network model can be trained based on a large amount of experimental data. This neural network model can output the charging and discharging currents based on the input battery state parameters.

[0156] Optionally, in addition to the charging current and discharging current, in the above method embodiments, the first cumulative charging threshold and the second cumulative charging threshold may be the same or different. The first cumulative discharging threshold and the second cumulative discharging threshold may be the same or different. At least one of the first cumulative charging threshold, the second cumulative charging threshold, the first cumulative discharging threshold, and the second cumulative discharging threshold may be a preset threshold. Alternatively, at least one of the first cumulative charging threshold, the second cumulative charging threshold, the first cumulative discharging threshold, and the second cumulative discharging threshold may also be a threshold determined based on the battery's state parameters.

[0157] In addition, after the charging and discharging device charges the battery and controls the battery to discharge based on the second charging current and the second discharging current, the cumulative discharge threshold and the cumulative charge threshold in the subsequent charging and discharging process can be preset thresholds or thresholds determined according to the battery's state parameters.

[0158] Through the above application embodiments, if at least one of the first cumulative charge threshold, the second cumulative charge threshold, the first cumulative discharge threshold, and the second cumulative discharge threshold is a threshold determined based on the battery's state parameters, it can better adapt to the current state parameters of the battery, so as to better control the current charging process and / or discharging process, ensure the charge and discharge amounts, and achieve efficient charging of the battery.

[0159] Optionally, in the above method embodiments, at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current can be a current acquired by the BMS periodically or irregularly. As an example, at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current can be a current determined by the BMS periodically or irregularly based on the battery's state parameters. This current changes with the changes in the battery's state parameters. Specifically, the BMS can periodically acquire the battery's state parameters to determine at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current; or, the BMS can acquire the battery's state parameters in real time, and when the state parameters change irregularly, the BMS determines at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current based on the irregularly changing state parameters.

[0160] Furthermore, based on this, the BMS periodically or irregularly sends at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current to the charging and discharging device, so that the charging and discharging device charges the battery or controls the battery to discharge based on the periodically sent current.

[0161] In this implementation, during a single charge and / or discharge cycle, the charging and / or discharging currents are periodically or irregularly transmitted by the BMS. On one hand, this implementation allows for periodic or irregular adjustment of the charging and / or discharging currents to improve charging and discharging efficiency. On the other hand, the periodically or irregularly transmitted charging and / or discharging currents indicate that the BMS and battery are in normal condition, allowing the charging and discharging device to continue charging or discharging the battery. Therefore, in this implementation, if the charging and discharging device does not receive the periodically or irregularly transmitted charging and / or discharging currents from the BMS, it can stop charging the battery and / or stop controlling battery discharge to ensure battery safety.

[0162] Figure 7 A schematic flowchart of another battery charging method 700 provided in an embodiment of this application is shown.

[0163] Based on the above Figure 2 Method 200 shown, such as Figure 7 As shown, step 210 above may include:

[0164] Step 710: The BMS periodically acquires the first charging current.

[0165] Step 220 above may include:

[0166] Step 720: The BMS periodically sends the first charging current to the charging and discharging device.

[0167] Step 240 above may include:

[0168] Step 740: If the first cumulative charge of the battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, periodically obtain the first discharge current.

[0169] Step 250 above may include:

[0170] Step 750: The BMS periodically sends the first discharge current to the charging and discharging device.

[0171] Step 270 above may include:

[0172] Step 770: If the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, periodically obtain the second charging current.

[0173] Step 280 above may include:

[0174] Step 780: The BMS periodically sends a second charging current to the charging and discharging device.

[0175] In addition to the above, other steps of method 700 in the embodiments of this application can be found in the above text. Figure 2 The relevant descriptions of the embodiments shown will not be repeated here.

[0176] In this embodiment, the BMS can periodically acquire a first charging current, a first discharging current, and a second charging current. Correspondingly, the BMS can periodically send the first charging current, the first discharging current, and the second charging current to the charging and discharging device.

[0177] Understandably, in the above embodiments, in addition to the current information required for charging and discharging, the voltage information required for charging and discharging is also required for charging and discharging the battery. The method of obtaining the voltage required for charging and discharging does not impose any limitation on the embodiments of the present invention.

[0178] Optionally, in the above method embodiments, the communication between the BMS and the charging / discharging device is compatible with the existing communication protocol between the charger and the BMS. Therefore, the communication between the BMS and the charging / discharging device is easy to implement and has good application prospects.

[0179] Specifically, based on the above method embodiments, the BMS can also acquire at least one of a first charging voltage, a second charging voltage, a first discharging voltage, and a second discharging voltage, and send at least one of the first charging voltage, the second charging voltage, the first discharging voltage, and the second discharging voltage to the charging and discharging device. The first charging current and the first charging voltage are carried in a first battery charging demand (BCL) message, and / or the first discharging current and the first discharging voltage are carried in a second BCL message, and / or the second charging current and the second charging voltage are carried in a third BCL message, and / or the second discharging current and the second discharging voltage are carried in a fourth BCL message.

[0180] In addition, after the charging and discharging device charges the battery and controls the battery discharge based on the second charging current and the second discharging current, the charging current, charging voltage, discharging current and discharging voltage in the subsequent charging and discharging process can also be carried in the BCL message and sent to the charging and discharging device through the BMS.

[0181] Figure 8 A schematic flowchart of another battery charging method 800 provided in an embodiment of this application is shown.

[0182] like Figure 8 As shown, the battery charging method 800 may include the following steps.

[0183] Step 810: The BMS acquires the first charging current and the first charging voltage.

[0184] Step 820: The BMS sends a first BCL message to the charging and discharging device, which carries the first charging current and the first charging voltage.

[0185] Step 830: The charging and discharging device charges the battery based on the first charging current and the first charging voltage.

[0186] Step 840: If the first cumulative charge of the battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS obtains the first discharge current and the first discharge voltage.

[0187] Step 850: The BMS sends a second BCL message to the charging and discharging device, which carries the first discharge current and the second discharge voltage.

[0188] Step 860: The charging and discharging device controls the battery to discharge based on the first discharge current and the second discharge voltage.

[0189] Step 870: If the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS obtains the second charging current and the second charging voltage.

[0190] Step 880: The BMS sends a third BCL message to the charging and discharging device, which carries the second charging current and the second charging voltage.

[0191] Step 890: The charging and discharging device charges the battery based on the second charging current and the second charging voltage.

[0192] In this embodiment, the battery charging request (BCL) message in the existing communication protocol between the charger and the BMS is used. The BMS sends charging current and discharging current to the charging and discharging device, and the charging and discharging device charges the battery or controls the battery to discharge based on the received charging current and discharging current.

[0193] Optionally, in the BCL message, the charging voltage (including the first charging voltage and the second charging voltage) and the discharging voltage (including the first discharging voltage and the second discharging voltage) have different ranges, and the charging current (including the first charging current and the second charging current) and the discharging current (including the first discharging current and the second discharging current) have different ranges. The charging and discharging device can determine whether the BCL message received belongs to the charging voltage and charging current or the discharging voltage and discharging current by the magnitude of the voltage and current carried therein.

[0194] Optionally, the BMS can determine the charging voltage and discharging voltage based on the battery's state parameters, or the charging voltage and discharging voltage can be preset values.

[0195] Optionally, in some embodiments, the BMS can periodically acquire charging current and charging voltage, and periodically send BCL messages carrying the charging current and charging voltage to the charging and discharging device. Similarly, the BMS can periodically acquire discharging current and discharging voltage, and periodically send BCL messages carrying the discharging current and discharging voltage to the charging and discharging device. In this embodiment, the periodic transmission method of BCL messages can be the same as the periodic transmission method of BCL messages in existing standards.

[0196] The above embodiments use information exchange messages of charging and discharging current and / or voltage as an example for illustration. It can be understood that in order to realize the charging and discharging of the battery, in addition to the processing during the charging and discharging stage, it may also include handshake interaction between the vehicle and the charger before charging and discharging, parameter configuration interaction during charging and discharging, etc. The embodiments of the present invention do not make specific limitations in this regard.

[0197] Optionally, the communication protocol between the charger and the BMS includes communication protocols in vehicle-to-grid (V2G) mode and grid-to-vehicle (G2V) mode.

[0198] The above text combined Figures 2 to 8Specific embodiments of the battery charging method provided in this application are illustrated below. Figures 9 to 12 The following describes specific embodiments of the related devices provided in this application. It is understood that the relevant descriptions in the following device embodiments can be referred to the foregoing method embodiments, and for the sake of brevity, they will not be repeated.

[0199] Figure 9 A schematic structural block diagram of a battery management system (BMS) 900 according to an embodiment of this application is shown. Figure 9 As shown, the BMS 900 includes: an acquisition unit 910, a transmission unit 920, and a processing unit 930.

[0200] In one embodiment of this application, the acquisition unit 910 is used to acquire a first charging current; the sending unit 920 is used to send the first charging current to the charging and discharging device so that the charging and discharging device charges the battery based on the first charging current; the processing unit 930 is used to determine that when the first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the acquisition unit 910 is further used to acquire a first discharge current; the sending unit 920 is further used to send the first discharge current to the charging and discharging device so that the charging and discharging device controls the battery to discharge based on the first discharge current; optionally, when the processing unit 930 determines that the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the acquisition unit 910 is further used to acquire a second charging current; the sending unit 920 is further used to send the second charging current to the charging and discharging device so that the charging and discharging device charges the battery based on the second charging current.

[0201] Optionally, when the processing unit 930 determines that the second cumulative charge of the battery is greater than or equal to the second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the acquisition unit 910 is further configured to acquire the second discharge current; the sending unit 920 is further configured to send the second discharge current to the charging and discharging device so that the charging and discharging device controls the battery discharge based on the second discharge current.

[0202] Optionally, the processing unit 930 is further configured to determine that the voltage of a single battery cell exceeds the full charge voltage of the single battery cell, and the sending unit 920 is further configured to send a charging stop command to the charging and discharging device, the charging stop command being used to instruct the charging and discharging device to stop charging the battery.

[0203] Optionally, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0204] Optionally, the discharge rate of the first discharge current and / or the second discharge current ranges from 0.1C to 1C.

[0205] Optionally, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%, and / or the ratio of the second cumulative discharge threshold to the second cumulative charge threshold is less than or equal to 10%.

[0206] Optionally, the acquisition unit 910 is used to acquire the state parameters of the battery and determine a first charging current based on the state parameters; and / or, the acquisition unit 910 is used to acquire the state parameters of the battery and determine a first discharging current based on the state parameters; and / or, the acquisition unit 910 is used to acquire the state parameters of the battery and determine a first discharging current based on the state parameters; wherein, the state parameters of the battery include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge, and battery health state.

[0207] Optionally, the acquisition unit 910 is used to periodically acquire a first charging current, and the transmission unit 920 is used to periodically transmit the first charging current to the charging and discharging device; and / or, the acquisition unit 910 is used to periodically acquire a first discharging current, and the transmission unit 920 is used to periodically transmit the first discharging current to the charging and discharging device; and / or, the acquisition unit 910 is used to periodically acquire a second charging current, and the transmission unit 920 is used to periodically transmit the second charging current to the charging and discharging device.

[0208] Optionally, the acquisition unit 910 is further configured to acquire a first charging voltage, and the sending unit 920 is further configured to send the first charging voltage to the charging and discharging device, wherein the first charging current and the first charging voltage are carried in a first battery charging demand (BCL) message; and / or, the acquisition unit 910 is further configured to acquire a first discharging voltage, and the sending unit 920 is further configured to send the first discharging voltage to the charging and discharging device, wherein the first discharging current and the first discharging voltage are carried in a second BCL message; and / or, the sending unit 920 is further configured to acquire a second charging voltage, and the sending unit 920 is further configured to send the second charging voltage to the charging and discharging device, wherein the second charging current and the second charging voltage are carried in a third BCL message; and / or, the acquisition unit 910 is further configured to acquire a second discharging voltage, and the sending unit 920 is further configured to send the second discharging voltage to the charging and discharging device, wherein the second discharging current and the second discharging voltage are carried in a fourth BCL message.

[0209] Figure 10 A schematic structural block diagram of a charging and discharging device 1000 according to one embodiment of this application is shown. Figure 10 As shown, the charging and discharging device 1000 includes a receiving unit 1010 and a processing unit 1020.

[0210] In one embodiment of this application, the receiving unit 1010 is used to receive a first charging current sent by the battery management system (BMS); the processing unit 1020 is used to charge the battery based on the first charging current; the receiving unit 1010 is also used to receive a first discharging current sent by the BMS, and the processing unit 1020 is also used to control the battery to discharge based on the first discharging current, wherein the first discharging current is the discharging current sent by the BMS when the first cumulative charge of the battery is greater than or equal to a first cumulative charge threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell; the receiving unit 1010 is also used to receive a second charging current sent by the BMS, and the processing unit 1020 is also used to charge the battery based on the second charging current, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge of the battery is greater than or equal to a first cumulative discharge threshold.

[0211] Optionally, the receiving unit 1010 is further configured to receive a second discharge current sent by the BMS, and the processing unit 1020 is further configured to control the battery discharge based on the second discharge current, wherein the second discharge current is the discharge current sent by the BMS when the second cumulative charge of the battery is greater than or equal to the second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell.

[0212] Optionally, the receiving unit 1010 is further configured to receive a charging stop command sent by the BMS, and the processing unit 1020 is configured to stop charging the battery. The charging stop command is a command sent by the BMS when the voltage of a single battery cell exceeds the full charge voltage of the single battery cell.

[0213] Optionally, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0214] Optionally, the discharge rate of the first discharge current and / or the second discharge current ranges from 0.1C to 1C.

[0215] Optionally, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%, and / or the ratio of the second cumulative discharge threshold to the second cumulative charge threshold is less than or equal to 10%.

[0216] Optionally, at least one of the first charging current, the first discharging current, and the second charging current is determined by the BMS based on the battery's state parameters; wherein the battery's state parameters include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge, and battery health status.

[0217] Optionally, the receiving unit 1010 is used to periodically receive a first charging current sent by the BMS; and / or, the receiving unit 1010 is used to periodically receive a first discharging current sent by the BMS; and / or, the receiving unit 1010 is used to periodically receive a second charging current sent by the BMS.

[0218] Optionally, the receiving unit 1010 is further configured to receive a first charging voltage sent by the BMS, wherein the first charging voltage and the first charging current are carried in a first battery charging demand (BCL) message; and / or, the receiving unit 1010 is further configured to receive a first discharging voltage sent by the BMS, wherein the first discharging voltage and the first discharging current are carried in a second BCL message; and / or, the receiving unit 1010 is further configured to receive a second charging voltage sent by the BMS, wherein the second charging voltage and the second charging current are carried in a third BCL message; and / or, the receiving unit 1010 is further configured to receive a second discharging voltage sent by the BMS, wherein the second discharging voltage and the second discharging current are carried in a fourth BCL message.

[0219] The above text combined Figures 2 to 10 This application describes a method and apparatus embodiment for battery charging based on information interaction between a charging / discharging device and a BMS. For the charging / discharging device, different hardware architectures can be used to charge the battery and control its discharge.

[0220] Figure 11 A schematic structural block diagram of another charging and discharging device provided in an embodiment of this application is shown.

[0221] like Figure 11 As shown, the charging and discharging device 1100 may include a control unit 1110 and a power conversion unit 1120.

[0222] In one embodiment, the control unit 1110 is configured to receive a first charging current sent by the BMS and, based on the first charging current, control the power conversion unit 1120 to charge the battery; the control unit 1110 is also configured to receive a first discharging current sent by the BMS and, based on the first discharging current, control the power conversion unit 1120 to discharge the battery, wherein the first discharging current is the discharging current sent by the BMS when the first cumulative charge of the battery is greater than or equal to a first cumulative charge threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell; the control unit 1110 is also configured to receive a second charging current sent by the BMS and, based on the second charging current, control the power conversion unit 1120 to charge the battery, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge of the battery is greater than or equal to the first cumulative discharge threshold.

[0223] Specifically, the power conversion unit 1120 may include high-voltage devices for high-power energy conversion, while the control unit 1110 may include low-voltage circuits for controlling the high-voltage devices in the power conversion unit 1120. In addition, the control unit 1110 may establish a communication connection with the BMS. For example, by way of example but not limitation, the control unit 1110 may establish a communication connection with the BMS via a communication bus, or it may establish a communication connection with the BMS via a wireless network.

[0224] Alternatively, as an example, Figure 12 A schematic structural block diagram of a power conversion unit 1120 provided in an embodiment of this application is shown.

[0225] like Figure 12 As shown, the power conversion unit 1120 can be connected to an alternating current (AC) power source and a battery. The power conversion unit 1120 includes an alternating current / direct current (AC / DC) converter 1210 and a direct current / direct current (DC / DC) converter 1220. The first terminal of the AC / DC converter 1210 is connected to the AC power source, the second terminal of the AC / DC converter 1210 is connected to the first terminal of the DC / DC converter 1220, and the second terminal of the DC / DC converter 1220 is connected to the battery to realize current transfer between the battery and the AC power source.

[0226] In this case, the control unit 1110 can control the AC / DC converter 1210 and the DC / DC converter 1220 to charge the battery through AC power based on the first charging current, and the control unit 1110 can also control the AC / DC converter 1210 and the DC / DC converter 1220 to charge the battery through AC power based on the second charging current.

[0227] In one embodiment, AC / DC converter 1210 may be a bidirectional AC / DC converter and DC / DC converter 1220 may be a bidirectional DC / DC converter. In this case, control unit 1110 may control bidirectional AC / DC converter 1210 and bidirectional DC / DC converter 1220 based on a first discharge current so that the battery discharges into the AC power supply.

[0228] In another embodiment, AC / DC converter 1210 may be a unidirectional AC / DC converter, and DC / DC converter 1220 may be a bidirectional DC / DC converter. In this case, the bidirectional DC / DC converter may be connected to an energy storage device, such as an energy storage battery. Control unit 1110 may control bidirectional DC / DC converter 1220 to release the battery's charge into the energy storage battery based on a first discharge current.

[0229] Optionally, the aforementioned AC power source includes, but is not limited to, the power grid, which can be used to provide three-phase AC power. The power grid can provide enough power to charge the battery and can also receive a large amount of power released by the battery.

[0230] Alternatively, in other embodiments, the AC power supply described above may also be a single-phase AC power supply. This application does not limit the specific type of AC power supply in its embodiments.

[0231] It should be noted that, in the embodiments of this application, the power conversion unit 1120, in addition to being able to... Figure 12 As shown, in addition to being connected to an AC power source, it can also be connected to a DC power source. In this case, the power conversion unit 1120 may only include a DC / DC converter to realize current transfer between the battery and the DC power source.

[0232] Optionally, if the power conversion unit 1120 is connected to an AC power source and a battery, the power conversion unit 1120 includes a bidirectional AC / DC converter and a bidirectional DC / DC converter; the control unit 1110 is also used to receive a second discharge current sent by the BMS, and control the bidirectional AC / DC converter and the bidirectional DC / DC converter based on the second discharge current, so that the battery discharges into the AC power source, wherein the second discharge current is the discharge current sent by the BMS when the second cumulative charge of the battery is greater than or equal to the second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell.

[0233] Optionally, the control unit 1110 is also configured to receive a charging stop command sent by the BMS, and control the bidirectional AC / DC converter and the bidirectional DC / DC converter to stop charging the battery based on the charging stop command, wherein the charging stop command is a command sent by the BMS when the voltage of a battery cell exceeds the full charge voltage of the battery cell.

[0234] Optionally, the control unit 1110 is used to periodically receive a first charging current sent by the BMS; and / or, the control unit 1110 is used to periodically receive a first discharging current sent by the BMS; and / or, the control unit 1110 is used to periodically receive a second charging current sent by the BMS.

[0235] Optionally, the control unit 1110 is further configured to receive a first charging voltage sent by the BMS, wherein the first charging voltage and a first charging current are carried in a first battery charging demand (BCL) message, and the control unit 1110 is configured to control the power conversion unit 1120 to charge the battery based on the first charging current and the first charging voltage; and / or, the control unit 1110 is further configured to receive a first discharging voltage sent by the BMS, wherein the first discharging voltage and a first discharging current are carried in a second BCL message, and the control unit 1110 is configured to control the power conversion unit 1120 to charge the battery based on the first discharging current and the first discharging voltage. Discharging; and / or, the control unit 1110 is further configured to receive a second charging voltage sent by the BMS, wherein the second charging voltage and the second charging current are carried in a third BCL message, and the control unit 1110 is configured to control the power conversion unit 1120 to charge the battery based on the second charging current and the second charging voltage; and / or, the control unit 1110 is further configured to receive a second discharging voltage sent by the BMS, wherein the second discharging voltage and the second discharging current are carried in a fourth BCL message, and the control unit 1110 is configured to control the power conversion unit 1120 to discharge the battery based on the second discharging current and the second discharging voltage.

[0236] In addition, the technical solutions related to charging current, discharging current, cumulative charging amount, cumulative discharging amount, cumulative charging amount threshold, and cumulative discharging amount threshold in the embodiments of this application can be found in the relevant descriptions above, and will not be elaborated further here.

[0237] Figure 13 A schematic structural block diagram of an electronic device 1300 according to an embodiment of this application is shown. Figure 13 As shown, the electronic device 1300 includes a memory 1310 and a processor 1320, wherein the memory 1310 is used to store a computer program, and the processor 1320 is used to read the computer program and execute the methods of the various embodiments of the present application based on the computer program.

[0238] Optionally, the electronic device 1300 can be used in any one or more of the BMS and the charging / discharging device. In the embodiments of this application, in addition to the processor in the charging / discharging device reading the corresponding computer program and executing the charging method corresponding to the charging / discharging device in the aforementioned embodiments based on the computer program, the processor in the BMS can also read the corresponding computer program and execute the charging method corresponding to the BMS in the aforementioned embodiments based on the computer program.

[0239] Furthermore, embodiments of this application also provide a readable storage medium for storing a computer program that performs the methods described in the various embodiments of this application. Optionally, the computer program may be a computer program in the aforementioned charging / discharging device and / or BMS.

[0240] It should be understood that the specific examples in this document are only intended to help those skilled in the art better understand the embodiments of this application, and are not intended to limit the scope of the embodiments of this application.

[0241] It should also be understood that, in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0242] It should also be understood that the various implementation methods described in this specification can be implemented individually or in combination, and the embodiments of this application are not limited in this respect.

[0243] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for charging a battery, characterized in that, include: The battery management system (BMS) acquires a first charging current and sends the first charging current to the charging and discharging device so that the charging and discharging device charges the battery based on the first charging current. If the first cumulative charge of the battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS obtains the first discharge current and sends the first discharge current to the charging and discharging device so that the charging and discharging device controls the battery to discharge based on the first discharge current. If the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS obtains the second charging current and sends the second charging current to the charging and discharging device so that the charging and discharging device charges the battery based on the second charging current. Wherein, the first cumulative charge threshold and / or the first cumulative discharge threshold are determined based on the state parameters of the battery, and the state parameters of the battery include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge and battery health status. The duration of the first discharge current is shorter than the duration of the first charging current, and the duration of the second charging current is shorter than the duration of the first charging current.

2. The method according to claim 1, characterized in that, The method further includes: If the second cumulative charge of the battery is greater than or equal to the second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the BMS acquires the second discharge current and sends the second discharge current to the charging and discharging device so that the charging and discharging device controls the battery to discharge based on the second discharge current.

3. The method according to claim 1 or 2, characterized in that, The method further includes: If the voltage of a single battery cell exceeds the full charge voltage of that cell, the BMS sends a charging stop command to the charging / discharging device, which instructs the charging / discharging device to stop charging the battery.

4. The method according to any one of claims 1 to 3, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

5. The method according to any one of claims 1 to 4, characterized in that, The discharge rate of the first discharge current ranges from 0.1C to 1C.

6. The method according to any one of claims 1 to 5, characterized in that, The ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

7. The method according to any one of claims 1 to 6, characterized in that, The BMS acquires the first charging current, including: The BMS acquires the state parameters of the battery and determines the first charging current based on the state parameters; and / or, The BMS acquires the first discharge current, including: The BMS acquires the state parameters of the battery and determines the first discharge current based on the state parameters; and / or, The BMS acquires the second charging current, including: The BMS acquires the state parameters of the battery and determines the second charging current based on the state parameters; The battery's state parameters include at least one of the following: battery temperature, battery voltage, battery current, battery state of charge, and battery health status.

8. The method according to any one of claims 1 to 7, characterized in that, The BMS acquires a first charging current and sends the first charging current to the charging and discharging device, including: The BMS periodically acquires the first charging current and periodically sends the first charging current to the charging and discharging device; and / or, The BMS acquires a first discharge current and sends the first discharge current to the charging and discharging device, including: The BMS periodically acquires the first discharge current and periodically sends the first discharge current to the charging and discharging device; and / or, The BMS acquires the second charging current and sends the second charging current to the charging and discharging device, including: The BMS periodically acquires the second charging current and periodically sends the second charging current to the charging and discharging device.

9. The method according to any one of claims 1 to 8, characterized in that, The method further includes: the BMS acquiring a first charging voltage and sending the first charging voltage to the charging and discharging device, wherein the first charging current and the first charging voltage are carried in a first battery charging demand message; and / or, The method further includes: the BMS acquiring a first discharge voltage and sending the first discharge voltage to the charging and discharging device, wherein the first discharge current and the first discharge voltage are carried in a second battery charging demand message; and / or, The method further includes: the BMS acquiring a second charging voltage and sending the second charging voltage to the charging and discharging device, wherein the second charging current and the second charging voltage are carried in a third battery charging demand message.

10. A method for charging a battery, characterized in that, include: The charging and discharging device receives a first charging current sent by the battery management system (BMS) and charges the battery based on the first charging current. The charging and discharging device receives a first discharge current sent by the BMS and controls the battery to discharge based on the first discharge current. The first discharge current is the discharge current sent by the BMS when the first cumulative charge of the battery is greater than or equal to a first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell. The charging and discharging device receives a second charging current sent by the BMS and charges the battery based on the second charging current, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold. Wherein, the first cumulative charge threshold and / or the first cumulative discharge threshold are determined based on the state parameters of the battery, and the state parameters of the battery include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge and battery health status. The duration of the first discharge current is shorter than the duration of the first charging current, and the duration of the second charging current is shorter than the duration of the first charging current.

11. The method according to claim 10, characterized in that, The method further includes: The charging and discharging device receives a second discharge current sent by the BMS and controls the battery to discharge based on the second discharge current. The second discharge current is the discharge current sent by the BMS when the second cumulative charge of the battery is greater than or equal to a second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell.

12. The method according to claim 10 or 11, characterized in that, The method further includes: The charging and discharging device receives a charging stop command sent by the BMS and stops charging the battery. The charging stop command is sent by the BMS when the voltage of a single battery cell exceeds the full charge voltage of the single battery cell.

13. The method according to any one of claims 10 to 12, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

14. The method according to any one of claims 10 to 13, characterized in that, The discharge rate of the first discharge current ranges from 0.1C to 1C.

15. The method according to any one of claims 10 to 14, characterized in that, The ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

16. The method according to any one of claims 10 to 15, characterized in that, At least one of the first charging current, the first discharging current and the second charging current is determined by the BMS based on the battery's state parameters; The battery's state parameters include at least one of the following: battery temperature, battery voltage, battery current, battery state of charge, and battery health status.

17. The method according to any one of claims 10 to 16, characterized in that, The charging and discharging device receives a first charging current sent by the BMS, including: The charging and discharging device periodically receives the first charging current sent by the BMS; and / or, The charging and discharging device receives the first discharge current sent by the BMS, including: The charging and discharging device periodically receives a first discharge current sent by the BMS; and / or, The charging and discharging device receives a second charging current sent by the BMS, including: The charging and discharging device periodically receives a second charging current sent by the BMS.

18. The method according to any one of claims 10 to 17, characterized in that, The method further includes: the charging and discharging device receiving a first charging voltage sent by the BMS, wherein the first charging voltage and the first charging current are carried in a first battery charging demand message; and / or, The method further includes: the charging / discharging device receiving a first discharge voltage sent by the BMS, wherein the first discharge voltage and the first discharge current are carried in a second battery charging demand message; and / or, The method further includes: the charging and discharging device receiving a second charging voltage sent by the BMS, wherein the second charging voltage and the second charging current are carried in a third battery charging demand message.

19. A battery management system (BMS), characterized in that, include: Acquisition unit, used to acquire the first charging current; A transmitting unit is configured to transmit the first charging current to a charging and discharging device so that the charging and discharging device charges the battery based on the first charging current. The processing unit is used to determine that when the first cumulative charge of the battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the acquisition unit is also used to acquire the first discharge current. The transmitting unit is further configured to transmit the first discharge current to the charging and discharging device, so that the charging and discharging device controls the battery to discharge based on the first discharge current. The processing unit is further configured to determine that when the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge threshold, the acquisition unit is further configured to acquire the second charging current. The transmitting unit is further configured to transmit the second charging current to the charging and discharging device, so that the charging and discharging device charges the battery based on the second charging current; Wherein, the first cumulative charge threshold and / or the first cumulative discharge threshold are determined based on the state parameters of the battery, and the state parameters of the battery include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge and battery health status. The duration of the first discharge current is shorter than the duration of the first charging current, and the duration of the second charging current is shorter than the duration of the first charging current.

20. The BMS according to claim 19, characterized in that, The processing unit is further configured to determine that when the second cumulative charge of the battery is greater than or equal to the second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell, the acquisition unit is further configured to acquire the second discharge current. The transmitting unit is further configured to transmit the second discharge current to the charging and discharging device, so that the charging and discharging device controls the battery to discharge based on the second discharge current.

21. The BMS according to claim 19 or 20, characterized in that, The processing unit is further configured to determine that the voltage of a single battery cell exceeds the full charge voltage of the single battery cell, and the sending unit is further configured to send a charging stop command to the charging and discharging device, the charging stop command being used to instruct the charging and discharging device to stop charging the battery.

22. The BMS according to any one of claims 19 to 21, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

23. The BMS according to any one of claims 19 to 22, characterized in that, The discharge rate of the first discharge current ranges from 0.1C to 1C.

24. The BMS according to any one of claims 19 to 23, characterized in that, The ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

25. The BMS according to any one of claims 19 to 24, characterized in that, The acquisition unit is used to acquire the state parameters of the battery and determine the first charging current based on the state parameters; and / or, The acquisition unit is used to acquire the state parameters of the battery and determine the first discharge current based on the state parameters; And / or, The acquisition unit is used to acquire the state parameters of the battery and determine the second charging current based on the state parameters; The battery's state parameters include at least one of the following: battery temperature, battery voltage, battery current, battery state of charge, and battery health status.

26. The BMS according to any one of claims 19 to 25, characterized in that, The acquisition unit is used to periodically acquire the first charging current, and the sending unit is used to periodically send the first charging current to the charging and discharging device. And / or, The acquisition unit is used to periodically acquire the first discharge current, and the sending unit is used to periodically send the first discharge current to the charging and discharging device. And / or, The acquisition unit is used to periodically acquire the second charging current, and the sending unit is used to periodically send the second charging current to the charging and discharging device.

27. The BMS according to any one of claims 19 to 26, characterized in that, The acquisition unit is further configured to acquire a first charging voltage, and the sending unit is further configured to send the first charging voltage to the charging and discharging device, wherein the first charging current and the first charging voltage are carried in a first battery charging demand message; and / or, The acquisition unit is further configured to acquire a first discharge voltage, and the sending unit is further configured to send the first discharge voltage to the charging and discharging device, wherein the first discharge current and the first discharge voltage are carried in a second battery charging demand message; and / or, The acquisition unit is further configured to acquire a second charging voltage, and the sending unit is further configured to send the second charging voltage to the charging and discharging device, wherein the second charging current and the second charging voltage are carried in a third battery charging demand message.

28. A charging and discharging device, characterized in that, include: The receiving unit is used to receive the first charging current sent by the battery management system (BMS). Processing unit, configured to charge the battery based on the first charging current; The receiving unit is further configured to receive the first discharge current sent by the BMS, and the processing unit is further configured to control the battery to discharge based on the first discharge current, wherein the first discharge current is the discharge current sent by the BMS when the first cumulative charge of the battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell. The receiving unit is further configured to receive a second charging current sent by the BMS, and the processing unit is further configured to charge the battery based on the second charging current, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge amount of the battery is greater than or equal to a first cumulative discharge amount threshold. Wherein, the first cumulative charge threshold and / or the first cumulative discharge threshold are determined based on the state parameters of the battery, and the state parameters of the battery include at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge and battery health status. The duration of the first discharge current is shorter than the duration of the first charging current, and the duration of the second charging current is shorter than the duration of the first charging current.

29. The charging and discharging device according to claim 28, characterized in that, The receiving unit is further configured to receive a second discharge current sent by the BMS, and the processing unit is further configured to control the battery discharge based on the second discharge current, wherein the second discharge current is the discharge current sent by the BMS when the second cumulative charge of the battery is greater than or equal to a second cumulative charge threshold and the voltage of the battery cell does not exceed the full charge voltage of the battery cell.

30. The charging and discharging device according to claim 28 or 29, characterized in that, The receiving unit is also used to receive a charging stop command sent by the BMS, and the processing unit is used to stop charging the battery. The charging stop command is a command sent by the BMS when the voltage of a single battery cell exceeds the full charge voltage of the single battery cell.

31. The charging and discharging device according to any one of claims 28 to 30, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

32. The charging and discharging device according to any one of claims 28 to 31, characterized in that, The discharge rate of the first discharge current ranges from 0.1C to 1C.

33. The charging and discharging device according to any one of claims 28 to 32, characterized in that, The ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

34. The charging and discharging device according to any one of claims 28 to 33, characterized in that, At least one of the first charging current, the first discharging current and the second charging current is determined by the BMS based on the battery's state parameters; The battery's state parameters include at least one of the following: battery temperature, battery voltage, battery current, battery state of charge, and battery health status.

35. The charging and discharging device according to any one of claims 28 to 34, characterized in that, The receiving unit is used to periodically receive the first charging current sent by the BMS; and / or, The receiving unit is used to periodically receive the first discharge current sent by the BMS; and / or, The receiving unit is used to periodically receive the second charging current sent by the BMS.

36. The charging and discharging device according to any one of claims 28 to 35, characterized in that, The receiving unit is further configured to receive a first charging voltage sent by the BMS, wherein the first charging voltage and the first charging current are carried in a first battery charging request message; and / or, The receiving unit is further configured to receive a first discharge voltage sent by the BMS, wherein the first discharge voltage and the first discharge current are carried in a second battery charging request message; and / or, The receiving unit is also used to receive the second charging voltage sent by the BMS, wherein the second charging voltage and the second charging current are carried in the third battery charging demand message.

37. A battery management system (BMS), characterized in that, include: It includes a processor and a memory, the memory being used to store a computer program, and the processor being used to invoke the computer program to perform a battery charging method as described in any one of claims 1 to 9.

38. A charging and discharging device, characterized in that, include: It includes a processor and a memory, the memory being used to store a computer program, and the processor being used to invoke the computer program to perform a battery charging method as described in any one of claims 10 to 18.

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