Charging and discharging device and method of charging a battery

Abstract

The embodiment of the present application provides a charging and discharging device and a battery charging method, which can guarantee the safety performance of a battery. The device comprises a bidirectional DC / DC converter and a control unit; the control unit is used for receiving a first charging current sent by a battery management system (BMS) of the battery, and controlling the bidirectional DC / DC converter to charge the battery by means of an energy storage battery based on the first charging current; receiving a first discharging current sent by the BMS, and controlling the bidirectional DC / DC converter to release the electric quantity of the battery into the energy storage battery based on the first discharging current; receiving a second charging current sent by the BMS, and controlling the bidirectional DC / DC converter to charge the battery by means of the energy storage battery based on the second charging current.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 202180076650.2, filed on July 29, 2021, entitled "Charging and Discharging Device and Method for Charging a Battery". Technical Field

[0002] This application relates to the field of batteries, and in particular to a charging and discharging device and a method for charging batteries. Background Technology

[0003] 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.

[0004] 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

[0005] This application provides a charging and discharging device and a method for charging a battery, which can ensure the safety performance of the battery.

[0006] In a first aspect, a charging and discharging device is provided, comprising: a bidirectional DC / DC converter and a control unit; the control unit is configured to: receive a first charging current sent by a battery management system (BMS) of the battery, and based on the first charging current, control the bidirectional DC / DC converter to charge the battery through an energy storage battery; receive a first discharging current sent by the BMS, and based on the first discharging current, control the bidirectional DC / DC converter to release the battery's charge into the energy storage battery, 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 battery cell does not exceed the full charge voltage of the single battery cell; receive a second charging current sent by the BMS, and based on the second charging current, control the bidirectional DC / DC converter to charge the battery through the energy storage battery, 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 a first cumulative discharge threshold.

[0007] 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, 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. This avoids battery safety issues caused by heat generation and lithium ion accumulation, such as battery combustion or explosion, thus ensuring battery safety performance. Furthermore, by charging and discharging the battery through an energy storage battery, the fast charging needs of the battery in different situations can be met.

[0008] In some embodiments, the control unit is further configured to: receive a second discharge current sent by the BMS, and based on the second discharge current, control the bidirectional DC / DC converter to release the battery's charge into the energy storage battery, wherein the second discharge current is the discharge current sent by the BMS when the battery's second cumulative charge is greater than or equal to a second cumulative charge threshold and the voltage of a single battery cell does not exceed the single battery cell's full charge voltage.

[0009] The technical solution implemented in this way, through information interaction between the BMS and the charging / discharging system, 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.

[0010] In some embodiments, the control unit is further configured to: determine, based on the first discharge current, that the discharge power demand of the battery is less than a discharge power threshold; and control the bidirectional DC / DC converter to release the battery's charge into the energy storage battery.

[0011] By releasing the battery's charge into the secondary battery, on the one hand, the discharge process can be increased during the battery charging process, eliminating lithium ion accumulation and improving the charging speed; on the other hand, the secondary battery can be charged, avoiding energy waste.

[0012] In some embodiments, the control unit is further configured to: determine, based on the first discharge current, that the discharge power demand of the battery is greater than or equal to a discharge power threshold; control the bidirectional DC / DC converter to release the first discharge power demand amount to the energy storage battery, and control the bidirectional DC / DC converter to release the second discharge power demand amount to the power grid through a second charging and discharging device, wherein the sum of the first discharge power demand and the second discharge power demand is equal to the discharge power demand.

[0013] In this embodiment, when the discharge power of the battery exceeds the discharge power threshold of the secondary battery, the charging and discharging device can release part of the power into the power grid, thereby ensuring the safety of the secondary battery while discharging during the charging process.

[0014] In some embodiments, the control unit is further configured to: acquire the state of charge (SOC) value of the energy storage battery; determine that the SOC is greater than or equal to a state of charge threshold, and control the bidirectional DC / DC converter to charge the battery through the energy storage battery based on the first charging current.

[0015] Before charging the battery, the charging and discharging device in this embodiment can determine the state of charge of the energy storage battery, and will only charge the battery when the energy storage battery has sufficient power.

[0016] In some embodiments, the control unit is further configured to: acquire the state of charge (SOC) value of the energy storage battery; specifically, the control unit is configured to: determine that the SOC is less than a state of charge threshold; send a charging request message to the second charging and discharging device, causing the second charging and discharging device to charge the energy storage battery through the power grid; determine that the SOC is greater than or equal to the state of charge threshold, and control the bidirectional DC / DC converter to charge the battery through the energy storage battery based on the first charging current.

[0017] When it is determined that the energy storage battery is low on power, the charging and discharging device in this embodiment can send a charging request message so that the power grid can charge the secondary battery. When the secondary battery is fully charged, it can then be used to charge the main battery, thereby improving charging efficiency.

[0018] In some embodiments, the control unit is further configured to: receive a charging stop command sent by the BMS and stop 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.

[0019] The charging and discharging device in this embodiment can adjust the switching of the charging and discharging process of the battery in a timely manner according to the real-time needs of the BMS, and determine whether to continue charging the battery, thereby improving charging efficiency.

[0020] In some embodiments, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0021] 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.

[0022] 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.

[0023] In some embodiments, the discharge rate of the first discharge current ranges from 0.1C to 1C.

[0024] 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.

[0025] In some embodiments, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

[0026] By using this technical solution, the ratio of the cumulative discharge threshold during the discharge process to the cumulative charging threshold during the charging process can be set to better control the amount of charge generated during charging and the amount of discharge generated during discharging, resulting in a smaller discharge amount and preventing excessive loss of the charged amount in the battery.

[0027] In some embodiments, 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.

[0028] 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.

[0029] In some embodiments, the control unit is specifically configured to: periodically receive the first charging current sent by the BMS; and / or periodically receive the first discharging current sent by the BMS; and / or periodically receive the second charging current sent by the BMS.

[0030] 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.

[0031] In some embodiments, 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 request message; and / or, receive a first discharging voltage sent by the BMS, wherein the first discharging voltage and the first discharging current are carried in a second battery charging request message; and / or, receive 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 request message.

[0032] In this implementation, the communication between the BMS and the charging / discharging device is compatible with the existing communication protocol between the charging pile and the BMS. Therefore, the communication between the BMS and the charging / discharging device is easy to implement and has good application prospects.

[0033] Secondly, a method for charging a battery is provided, which is applied to a charging and discharging device. The method includes: the charging and discharging device receiving a first charging current sent by a battery management system (BMS) of the battery, and controlling a bidirectional DC / DC converter in the charging and discharging device to charge the battery through an energy storage battery based on the first charging current; the charging and discharging device receiving a first discharging current sent by the BMS, and controlling the bidirectional DC / DC converter to release the battery's charge into the energy storage 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 battery cell does not exceed the full charge voltage of the single battery cell; the charging and discharging device receiving a second charging current sent by the BMS, and controlling the bidirectional DC / DC converter to charge the battery through the energy storage 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.

[0034] 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.

[0035] Fourthly, 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 / discharging device, so that the charging / discharging device charges the battery based on the first charging current; if the 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 / discharging device, so that the charging / 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 acquiring a second charging current and sending the second charging current to the charging / discharging device, so that the charging / discharging device charges the battery based on the second charging current.

[0036] Fifthly, a charging and discharging device is provided, including a processor and a memory for storing a computer program, and the processor for calling the computer program to execute a method as described in either of the second or any of the possible implementations of the second aspect above.

[0037] 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 methods as described in the fourth aspect and any of the possible implementations of the fourth aspect. Attached Figure Description

[0038] 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.

[0039] Figure 1 This is an architectural diagram of a charging system applicable to one embodiment of this application; Figure 2 This is a schematic flowchart of a battery charging method provided in an embodiment of this application; Figure 3 This is an architectural diagram of another charging system used in the embodiments of this application; Figure 4 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 5 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 6 This is a schematic waveform diagram of the charging current and discharging current of the battery provided in the embodiments of this application; Figure 7 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 8 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 9 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 10 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 11 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 12This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 13 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 14 This is a schematic flowchart of another battery charging method provided in an embodiment of this application; Figure 15 This is a schematic diagram of a battery charging process provided in an embodiment of this application; Figure 16 This is a schematic structural block diagram of a charging and discharging device provided in an embodiment of this application; Figure 17 This is a schematic structural block diagram of a battery management system (BMS) provided in an embodiment of this application; Figure 18 This is a schematic structural block diagram of an electronic device according to an embodiment of this application. Detailed Implementation

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] To ensure battery safety, this application proposes a new battery charging method and charging system.

[0045] Figure 1 An architecture diagram of a charging system applicable to an embodiment of this application is shown.

[0046] 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.

[0047] 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.

[0048] 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 / apparatus, or the BMS 122 can be installed as a separate device / apparatus outside the battery 121.

[0049] 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.

[0050] 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. This application embodiment does not limit the specific type or application scenario of the charging and discharging device 110.

[0051] Optionally, such as Figure 1 As shown, the charging and discharging device 110 can be connected to the battery 121 via a wire 150 and to the BMS 122 via a communication line 140, wherein the communication line 140 is used to realize information interaction between the charging and discharging device 110 and the BMS.

[0052] 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.

[0053] 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.

[0054] Figure 2 A schematic flowchart illustrating a battery charging method 200 applicable to embodiments 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.

[0055] like Figure 2 As shown, the battery charging method 200 may include the following steps.

[0056] Step 210: The Battery Management System (BMS) acquires the first charging current.

[0057] Step 220: The BMS sends the first charging current to the charging and discharging device.

[0058] Step 230: The charging and discharging device receives the first charging current and charges the battery based on the first charging current.

[0059] 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.

[0060] Step 250: The BMS sends the first discharge current to the charging and discharging device.

[0061] Step 260: The charging and discharging device receives the first discharge current and controls the battery to discharge based on the first discharge current.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Specifically, as mentioned above Figure 1 As 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 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 does not limit the specific way of consuming electrical energy.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] For battery charging, after one charge and one discharge cycle, the battery can be charged a second time to continue charging.

[0081] Optionally, such as Figure 2 As shown, the battery charging method 200 in this embodiment may further include the following steps.

[0082] 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.

[0083] Step 280: The BMS sends a second charging current to the charging and discharging device.

[0084] Step 290: The charging and discharging device receives the second charging current and charges the battery based on the second charging current.

[0085] 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.

[0086] 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.

[0087] Normally, charging and discharging devices can use the power grid to charge electric vehicles. However, in special environments such as large parking lots, further charging can be achieved... Figure 1 Based on this, an energy storage battery is added to charge the power battery, in order to meet the fast charging needs of electric vehicles in special scenarios.

[0088] Figure 3 A schematic diagram of the architecture of another charging system 30 to which embodiments of this application may be applied is shown. Figure 3 As shown, the charging system 30 may include: a charging and discharging device 310, a battery system 320, and an energy storage battery 330.

[0089] For a description of battery system 320, please refer to the above. Figure 1 Description of battery system 120 in the text.

[0090] Optionally, the energy storage battery 330 in this application embodiment can be a cascade battery, or the energy storage battery 330 can exist in the form of an energy storage station. The cascade battery or energy storage station can be charged by the grid, or it can be charged by direct current, such as photovoltaic power. This application embodiment does not limit this.

[0091] like Figure 3As shown, the charging and discharging device 310 may include a bidirectional DC / DC converter 311 and a control unit 312. In this case, the charging and discharging device 310 can be a DC charging station, which can output adjustable DC power to charge the power battery 321, such as the power battery of an electric vehicle. Specifically, the bidirectional DC / DC converter 311 in the charging and discharging device 310 can convert the power type output by the energy storage battery 330 to the power type required by the power battery 321, thereby enabling the charging of the power battery 321. The control unit 312 may include a controller and / or a processor for controlling the process of the bidirectional DC / DC converter 311 charging and discharging the power battery 321 through the energy storage battery 330, as well as the operation of other electrical components in the charging and discharging device 310.

[0092] Figure 4 A schematic flowchart of another battery charging method 400 according to an embodiment of this application is shown. Method 400 can be generated by... Figure 3 This is achieved through the charging system 30 in the middle.

[0093] like Figure 4 As shown, the battery charging method 400 includes steps 410 to 490.

[0094] and Figure 1 Compared to the charging system 10 in the previous embodiment, the charging system 30 applicable in this application embodiment has an energy storage battery 330, and the charging and discharging device 310 may include a bidirectional DC / DC converter 311 and a control unit 312. Therefore, the methods corresponding to the two charging systems are... Figure 2 and Figure 4 The charging methods may differ. The following describes the different steps in the two embodiments. The remaining steps are similar and will not be repeated in this application.

[0095] Steps 410 to 420 and Figure 2 Steps 210 to 220 are the same.

[0096] Step 430: The charging and discharging device receives the first charging current and controls the bidirectional DC / DC converter based on the first charging current to charge the battery through the energy storage battery.

[0097] Steps 440 to 450 and Figure 2 Steps 240 to 250 are the same.

[0098] Step 460: The charging and discharging device receives the first discharge current and, based on the first discharge current, controls the bidirectional DC / DC converter to release the battery's charge into the energy storage battery.

[0099] Steps 470 to 480 and Figure 2Steps 270 to 280 are the same.

[0100] Step 490: The charging and discharging device receives the second charging current and, based on the second charging current, controls the bidirectional DC / DC converter to charge the battery through the energy storage battery.

[0101] Since the current in the energy storage battery is direct current, the charging and discharging device can charge and discharge the battery through its bidirectional DC / DC converter.

[0102] The battery charging method 400 of this application embodiment allows the charging and discharging device to charge and discharge the battery based on the first charging current and the first discharging current sent by the BMS during the charging process, avoiding continuous charging and thus preventing problems such as heat generation and lithium-ion accumulation caused by continuous charging. Furthermore, the battery charging method in this application embodiment can utilize a bidirectional DC / DC converter in the charging and discharging device to charge and discharge the battery using an energy storage battery, thereby meeting the fast charging needs of power batteries in scenarios such as large parking lots.

[0103] Figure 5 A schematic flowchart of another battery charging method 500 provided in an embodiment of this application is shown.

[0104] like Figure 5 As shown, the battery charging method 500 may further include the following steps in addition to the steps 410 to 490 described above.

[0105] Step 510: 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.

[0106] Step 520: The BMS sends a second discharge current to the charging and discharging device.

[0107] Step 530: The charging and discharging device receives the second discharge current and controls the bidirectional DC / DC converter based on the second discharge current to release the charge of the battery into the energy storage battery.

[0108] 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 system. 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.

[0109] Specifically, in step 510, when the charging and discharging device charges the battery using the energy storage 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] Further, in step 510, 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 520 to 530, the BMS sends this second discharge current to the charging / discharging device, and the charging / discharging device controls the bidirectional DC / DC converter to release the energy into the energy storage battery based on the received second discharge current.

[0115] 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.

[0116] As an example, Figure 6 A schematic waveform diagram of the charging current and discharging current of a battery provided in an embodiment of this application is shown.

[0117] like Figure 6 As 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.

[0118] It should be noted that, Figure 6 The diagram only schematically shows the waveforms of the first charging current, the second charging current, the first discharging current, and the second discharging current. The first charging current can be as follows from t1 to t2: Figure 6 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 6 The current shown can be a constant current, or it can be a changing current that varies with time. Additionally, Figure 6 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.

[0119] exist Figure 4 and Figure 5 In the charging method, the charging and discharging device controls the bidirectional DC / DC converter to release the battery's charge based on the first discharge current. Optionally, the charging and discharging device can release all the charge to be released into the energy storage battery, or it can release part of the charge into the energy storage battery and the other part into the power grid.

[0120] Specifically, as one implementation method, Figure 7 This illustration shows another schematic diagram of a battery charging and discharging process provided in an embodiment of this application.

[0121] like Figure 7As shown, the charge / discharge process 700 includes steps 410 to 490, wherein steps 410 to 450 and 470 to 490 are the same as the aforementioned steps. Steps 461 and 462 may correspond to the aforementioned step 460.

[0122] Step 761: The charging and discharging device determines, based on the first discharge current, that the battery's discharge power requirement is less than the discharge power threshold.

[0123] Step 762: The charging and discharging device controls the bidirectional DC / DC converter to release the battery's charge into the energy storage battery.

[0124] It should be understood that the discharge power threshold in the embodiments of this application is the discharge power threshold of the energy storage battery. When it is determined that the discharge power demand of the power battery is less than the threshold of the energy storage battery, the power battery can release its charge into the energy storage battery. On the one hand, this can achieve the discharge of the power battery during the charging process, thus eliminating the lithium ion accumulation phenomenon. On the other hand, it can ensure that the amount of charge released by the power battery is within the range that the energy storage battery can accept, thereby ensuring the normal use of the energy storage battery. Moreover, the amount of charge released by the power battery can also charge the energy storage battery, avoiding energy waste.

[0125] It should be understood that the power threshold required for battery discharge can be calculated based on the battery's discharge current and discharge voltage.

[0126] Optionally, the charging and discharging system 30 in this embodiment may further include a second charging and discharging device 360 ​​and a power grid 370, wherein the second charging and discharging device 360 ​​may include a bidirectional AC / DC converter. Optionally, the second charging and discharging device 360 ​​may be connected to the energy storage battery 330 and the power grid 370 respectively via a high-voltage line 350.

[0127] Optionally, the second charging / discharging device 360 ​​may also include a control unit, which can interact with the charging / discharging device via a communication line 340.

[0128] As another implementation method Figure 8 This illustration shows another schematic diagram of a battery charging and discharging process provided in an embodiment of this application. For example... Figure 8 As shown, the battery discharge process 800 includes steps 410 to 490, wherein steps 410 to 450 and 470 to 490 are the same as the aforementioned steps. The following only describes the different steps.

[0129] Step 861: The charging and discharging device determines, based on the first discharge current, that the battery's discharge power requirement is greater than or equal to the discharge power threshold.

[0130] Step 862: Control the bidirectional DC / DC converter to release the first discharge power required by the energy storage battery. Step 863, and control the bidirectional DC / DC converter to release the second discharge demand power to the power grid through the second charging and discharging device. Wherein, the sum of the first discharge demand power and the second discharge demand power is equal to the discharge demand power.

[0131] When the discharge power demand of the power battery in this embodiment exceeds the discharge power threshold of the energy storage battery, the charging and discharging device can control the release of a portion of the power battery's charge into the energy storage battery and release the remaining power battery's charge into the power grid, such as... Figure 3 The power grid 370 is shown in the figure. Specifically, for example, the discharge power demand of the power battery can be Wsum, the discharge power threshold of the energy storage battery can be WDischglmt, the amount of the first discharge power demand can be the amount of the difference between the discharge power demand Wsum and the discharge power threshold WDischglmt, i.e., Wsum-WDischgLmt, and the second discharge power demand can be the same amount of the discharge power threshold, i.e., WDischgLmt. In this way, the power battery can achieve the discharge process during the charging process.

[0132] It should be understood that when the charging and discharging device in the embodiments of this application only includes a bidirectional DC / DC converter, it is a DC charging device, that is, it can only convert DC power into DC power of different power levels, but cannot perform AC power conversion. Therefore, in order to release the power battery's charge into the power grid, the charging and discharging device in the embodiments of this application can also control the bidirectional DC / DC converter to discharge through a second charging and discharging device. Optionally, the second charging and discharging device may include a bidirectional AC / DC converter. Specifically, for example, the charging and discharging device can release the power battery's charge into the power grid through the bidirectional DC / DC converter and the bidirectional AC / DC converter in the second charging and discharging device.

[0133] Since the charging system in this embodiment utilizes an energy storage battery to charge and discharge the battery, and the energy storage battery cannot charge the battery when its power is insufficient, this is one implementation method. Figure 9 A flowchart illustrating another battery charging method according to an embodiment of this application is provided.

[0134] like Figure 9 As shown, the battery charging and discharging process 900 includes steps 410 to 490, of which only the different steps are described below.

[0135] Step 931: The charging and discharging device acquires the state of charge (SOC) value of the energy storage battery.

[0136] Step 932: The charging and discharging device determines that the SOC is greater than or equal to the state of charge threshold, and controls the bidirectional DC / DC converter to charge the battery through the energy storage battery based on the first charging current.

[0137] It should be understood that the energy storage battery in this application embodiment can charge the power battery only when its own power is greater than or equal to a certain threshold, and when its own power is less than the threshold, it can replenish its own power first and then charge the power battery.

[0138] and Figure 9 Conversely, as another implementation method, Figure 10 A flowchart illustrating another battery charging method according to an embodiment of this application is provided.

[0139] like Figure 10 As shown, the battery charging and discharging process 1000 includes steps 410 to 490, of which only the different steps are described below.

[0140] Step 1031: Obtain the state of charge (SOC) value of the energy storage battery.

[0141] Step 1032: Determine that the SOC is less than the state of charge threshold.

[0142] Step 1033: Send a charging request message to the second charging and discharging device, so that the second charging and discharging device charges the energy storage battery through the power grid.

[0143] Step 1034: Determine that the SOC is greater than or equal to the state of charge threshold, and based on the first charging current, control the bidirectional DC / DC converter to charge the battery through the energy storage battery.

[0144] It should be understood that the energy storage battery in this application can be charged via AC power when its charge is insufficient. Optionally, for example, the control unit can send a charging request message to the second charging and discharging device via a communication line, requesting the second charging and discharging device to charge the energy storage battery through the power grid. In this case, the second charging and discharging device may include an AC / DC converter. Alternatively, the energy storage battery in the embodiments of this application can also be charged via DC power. In this case, the energy storage battery can be charged via DC power, such as photovoltaic power, using the DC / DC converter in the second charging and discharging device. This application does not limit the charging method of the energy storage battery.

[0145] Optionally, the power battery in this application embodiment can also be directly charged by the power grid. For example, the power grid can directly charge the power battery through a second charging and discharging device (such as the bidirectional AC / DC converter therein) and the charging and discharging device in this application (such as the bidirectional DC / DC converter therein).

[0146] Figure 11 A schematic flowchart of another battery charging method 1100 provided in an embodiment of this application is shown.

[0147] like Figure 11 As shown, in addition to steps 410 to 490 described above, the battery charging method 1100 may further include the following steps.

[0148] Step 1110: 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.

[0149] Step 1120: The charging / discharging device stops charging the battery.

[0150] 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.

[0151] Optionally, steps 1110 and 1120 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 individual battery cells to determine whether the battery has reached a fully charged state. Once the voltage of the individual battery cells exceeds the full charge voltage of the individual battery cells, the BMS sends a charging stop command to the charging and discharging device to stop charging the battery.

[0152] therefore, Figure 11 The steps 1110 and 1120 are shown only schematically after step 490, i.e. during the second charging process. It can be understood that steps 1110 and 1120 can also be performed during any one of the multiple charging and discharging processes.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] Furthermore, in this embodiment, the discharge current is a small current, which is intended 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.

[0158] 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.

[0159] 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.

[0160] Optionally, in the above method, in order to better control the amount of battery charging during charging and the amount of battery discharging during discharging, a cumulative discharge threshold and a ratio of the cumulative charging threshold during charging can be set to make the discharge amount smaller and prevent excessive loss of the charged amount in the battery.

[0161] 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%.

[0162] 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%.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] Figure 12 A schematic flowchart of another battery charging method 1200 provided in an embodiment of this application is shown.

[0169] Based on the above Figure 4 Method 400 shown, such as Figure 12 As shown, step 410 above may include: Step 1210: The BMS acquires the state parameters of the battery and determines the first charging current based on the state parameters.

[0170] Step 240 above may include: Step 1240: 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 state parameters of the battery and determines the first discharge current based on the state parameters.

[0171] Step 470 above may include: Step 1270: 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 state parameters of the battery and determines the second charging current based on the state parameters.

[0172] In addition, other steps of method 1200 in this application embodiment can be found above. Figure 4 The relevant descriptions of the embodiments shown will not be repeated here.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] Figure 13 A schematic flowchart of another battery charging method 1300 provided in an embodiment of this application is shown.

[0182] Based on the above Figure 4 Method 400 shown, such as Figure 13 As shown, step 410 above may include: Step 1310: BMS periodically acquires the first charging current.

[0183] Step 220 above may include: Step 1320: The BMS periodically sends a first charging current to the charging and discharging device.

[0184] Step 240 above may include: Step 1340: 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 first discharge current is periodically acquired.

[0185] Step 250 above may include: Step 1350: The BMS periodically sends a first discharge current to the charging and discharging device.

[0186] Step 270 above may include: Step 1370: 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.

[0187] Step 280 above may include: Step 1380: The BMS periodically sends a second charging current to the charging and discharging device.

[0188] In addition, other steps of method 1300 in this application embodiment can be found above. Figure 4 The relevant descriptions of the embodiments shown will not be repeated here.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] Figure 14 A schematic flowchart of another battery charging method 1400 provided in an embodiment of this application is shown.

[0195] like Figure 14 As shown, the battery charging method 1400 may include the following steps.

[0196] Step 1410: The BMS acquires the first charging current and the first charging voltage.

[0197] Step 1420: The BMS sends a first BCL message to the charging and discharging device, which carries a first charging current and a first charging voltage.

[0198] Step 1430: The charging and discharging device charges the battery based on the first charging current and the first charging voltage.

[0199] Step 1440: 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.

[0200] Step 1450: The BMS sends a second BCL message to the charging and discharging device, which carries the first discharge current and the second discharge voltage.

[0201] Step 1460: The charging and discharging device controls the battery to discharge based on the first discharge current and the second discharge voltage.

[0202] Step 1470: 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.

[0203] Step 1480: The BMS sends a third BCL message to the charging and discharging device, which carries the second charging current and the second charging voltage.

[0204] Step 1490: The charging and discharging device charges the battery based on the second charging current and the second charging voltage.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] To further illustrate the charging and discharging process in the embodiments of this application, the following will be used as an example. Figure 15 The following is an example of a charging and discharging process diagram of an embodiment of this application, as shown in the figure. The charging and discharging device and BMS can be found in [reference needed]. Figure 4 A description of the charging and discharging system 30. (e.g.) Figure 15 As shown, the charging and discharging process includes: S1501a: After the user inserts the charging gun, the BMS enters the charging state according to the DC charging control process.

[0212] At the same time, the charging and discharging device can also sense the insertion status and proceed to step S1501b: After the user inserts the charging gun, the charging and discharging device enters the charging process state according to the DC charging control process. More specifically, this refers to the control unit in the charging and discharging device, such as... Figure 2 The control unit controls the charging and discharging device to enter the charging process state.

[0213] For ease of understanding, the battery in this application is described using the power battery in an electric vehicle as an example, but the embodiments of this application are not limited to this.

[0214] As an optional electrical connection method, the energy storage battery is equipped with a first charging gun, and the charging and discharging device can be equipped with a first charging socket corresponding to the first charging gun to receive electrical energy transferred from the energy storage battery. In addition, the charging and discharging device is also equipped with a second charging gun, which is used to electrically connect with a second charging socket on the electric vehicle to realize the transfer of electrical energy from the charging and discharging device to the battery of the electric vehicle.

[0215] To adapt to the electrical connection between existing charging and discharging devices and the battery system of electric vehicles, optionally, the specific type and structure of the second charging gun on the charging and discharging device can be the same as the specific type and structure of the first charging gun on the energy storage battery. Correspondingly, the specific type and structure of the first charging socket on the charging and discharging device can be the same as the specific type and structure of the second charging socket on the electric vehicle. Of course, the aforementioned second charging gun and first charging gun, as well as the first charging socket and second charging socket, can also be different. This application embodiment does not specifically limit this, aiming only to achieve electrical connection between the charging gun and its corresponding charging socket.

[0216] S1502, the BMS can obtain the battery cumulative charging capacity threshold QChgLmt based on the battery pack's status parameters and enter charging mode.

[0217] Optionally, the state parameters in the embodiments of this application may include the voltage, temperature, and SOH of a single cell. The BMS can obtain the cumulative charging capacity threshold for charging and discharging by looking up a table based on the above battery state parameters.

[0218] S1503, the BMS obtains the battery's charging current ReqChg_I and charging voltage demand based on the battery pack's state parameters.

[0219] It should be understood that the charging current demand obtained by the BMS can be the maximum charging current that the battery can allow under the current battery state. The charging current demand and charging voltage demand can also be obtained by the BMS through table lookup. Specifically, the BMS can obtain them by looking up the monitored battery state parameters.

[0220] It should be understood that the BMS can monitor the battery's state parameters in real time and obtain the real-time charging current and voltage requirements by looking up the data obtained from the monitoring. For example, the BMS can obtain the real-time charging current and voltage requirements according to a certain time period.

[0221] S1504, the BMS sends the charging current and charging voltage requirements obtained above to the charging and discharging device.

[0222] It should be understood that the BMS may also carry other relevant information, such as charging power demand, in the messages carrying charging current and charging voltage demand. This application embodiment does not limit this.

[0223] Optionally, the BMS can transmit the charging current and charging voltage information to the charging and discharging device via CAN communication, using the national standard charging standard.

[0224] After the charging and discharging device performs step S1501b and enters the charging state, it can obtain the current power status of the energy storage battery, such as the secondary battery, i.e., in S1505, obtain the SOC value of the secondary battery.

[0225] It should be understood that SOC here refers to the State of Charge (SOC), and the SOC value can reflect the available state of the remaining charge in the battery.

[0226] S1506, the charging and discharging device confirms whether it has received the charging demand information sent by the BMS, that is, the information sent by the BMS including the charging demand voltage and the charging demand current.

[0227] Optionally, the steps of obtaining the SOC of the secondary battery and determining whether a charging request from the BMS has been received can be performed simultaneously. Alternatively, the charging device can first determine that a charging request has been received and then obtain the SOC value of the secondary battery. This application embodiment does not limit this.

[0228] S1507, after obtaining the SOC value of the secondary battery, the charging and discharging device can first determine whether the SOC value of the secondary battery is greater than the SOC threshold (SOC) of the secondary battery.uplimit ).

[0229] By determining the relationship between the SOC of the secondary battery and the threshold, it can be ensured that the secondary battery is charged when it has sufficient power.

[0230] S1508, when the SOC value is greater than SOC uplimit At that time, the charging and discharging device can control the bidirectional DC / DC converter to start discharging, with an output power of W. SUM Specifically, the voltage output of the secondary battery can be converted using a bidirectional DC / DC converter to charge the battery.

[0231] S1509, or, when the charging / discharging device determines that the SOC value is less than or equal to the SOC value. uplimit At this time, the charging and discharging device can draw power from the grid through an AC / DC converter to charge the secondary battery until the SOC value of the secondary battery is greater than the SOC value. uplimit .

[0232] Optionally, as described above, when the charging and discharging device in this embodiment only includes a bidirectional DC / DC converter, in order to achieve the purpose of drawing power from the grid to charge the secondary battery, the charging and discharging device can send a charging request message to other charging and discharging devices, including AC / DC converters, requesting the other charging and discharging devices to charge the secondary battery through the grid. Alternatively, when the charging and discharging device includes not only a bidirectional DC / DC converter but also an AC / DC converter, the charging and discharging device can directly control the AC / DC converter to draw power from the grid and charge the secondary battery.

[0233] S1510, the charging and discharging device converts the DC current in the secondary battery into the DC current required by the battery.

[0234] S1511, the charging and discharging device outputs DC current to the battery according to the requirements of the BMS to charge the battery.

[0235] S1512, the BMS calculates the cumulative charging capacity Qchg in real time during the charging process by using the current on the battery bus, where Qchg=I*t, and I is the charging current during the charging process.

[0236] Optionally, the aforementioned busbar may refer to Figure 2 The high-voltage line is 250.

[0237] S1513, the BMS determines whether the battery has reached a fully charged state based on the battery's maximum charging voltage, i.e., Ucell_max > Ucell_FullChg, where Ucell_max is the maximum charging voltage that the battery can be allowed to charge, and Ucell_FullChg is the voltage value at which the battery reaches a fully charged state.

[0238] S1514, When the BMS determines that the battery has reached full charge, it determines to end the charging process.

[0239] S1515, after the BMS determines that charging has ended, it sends a charging stop request command to the charging and discharging device.

[0240] S1516, The charging / discharging device determines whether it has received a charging stop request command.

[0241] S1517, if the charging / discharging device confirms that it has received a charging stop request command, it will proceed with the normal power-off process and end the charging process.

[0242] S1518, if the BMS determines that the maximum allowable charging voltage of the battery is less than the full charge voltage of the battery, then it further determines whether the cumulative charging capacity Qchg is greater than or equal to the charging capacity threshold Qchglmt.

[0243] If the BMS determines that the cumulative charging capacity Qchg is less than the charging capacity threshold Qchglmt, the BMS re-enters step 1503 and, based on the latest acquired charging current, enables the charging and discharging device to continue charging the battery.

[0244] Alternatively, in S1519, if the BMS determines that the cumulative charging capacity is greater than or equal to the charging capacity threshold, it can look up the cumulative discharge capacity threshold in a table based on the battery's state parameters and control the battery to enter the discharge mode.

[0245] S1520, the BMS further obtains the discharge demand current ReqDischg_I by looking up a table based on the battery's state parameters.

[0246] Optionally, the discharge demand current can be the maximum allowable discharge current, which can be obtained by acquiring the battery's state parameters and looking up a table at different temperatures.

[0247] S1521, the BMS sends a message to the charging and discharging device including the discharge demand current and discharge demand voltage, wherein the discharge demand power is Wsum_dischg.

[0248] S1522, after the charging and discharging device determines in step S1516 that it has not received a charging stop request command, or after the charging and discharging device receives the aforementioned discharge request current and discharge request voltage sent by the BMS, the charging and discharging device can determine whether it has received a discharge request message, i.e., the aforementioned information including the discharge request current and discharge request voltage.

[0249] If the charging and discharging device does not receive a discharge request message, it returns to step S1505.

[0250] S1523, if the charging and discharging device receives a discharge demand message, it determines whether the discharge demand power Wsum_dischg is greater than or equal to the discharge power threshold WDischgLmt, where the discharge power threshold is the threshold of the cascade battery.

[0251] S1524, if Wsum_dischg is greater than or equal to WDischgLm, the charging and discharging device releases the first discharge power required to the secondary battery and the second discharge power required to the power grid, wherein the first discharge power required is Wsum_dischg-WDischgLmt and the second discharge power required is WDischgLmt.

[0252] It should be understood that, as described above, to release the DC power from the battery into the power grid, the DC power needs to be converted into AC power. The charging and discharging device in this application embodiment can release the battery power into the power grid through a bidirectional DC / DC converter included in the charging and discharging device and a bidirectional AC / DC converter included in other charging and discharging devices. Alternatively, when the charging and discharging device includes a bidirectional AC / DC converter, the charging and discharging device can directly control the bidirectional DC / DC converter and the bidirectional AC / DC converter to release the battery power into the power grid.

[0253] S1525, or, when Wsum_dischg is less than WDischgLm, the charging and discharging device can release all the battery's charge into the secondary battery through a bidirectional DC / DC converter, with a discharge power of Wsum_dischg.

[0254] S1526, the charging and discharging device discharges the battery according to the requirements of the BMS.

[0255] S1527, the charging and discharging device outputs DC current according to the requirements of the BMS.

[0256] S1528, the BMS calculates the cumulative discharge capacity QDischg in real time by using the current on the battery bus, where QDischg=I*t, and I is the discharge demand current.

[0257] S1529, BMS determines whether QDischg is greater than or equal to the cumulative discharge capacity threshold QDischgLmt.

[0258] If QDischg is less than QDischgLmt, the BMS returns to step S1520, allowing the charging and discharging device to continue discharging the battery.

[0259] S1529, if QDischg is greater than or equal to QDischgLmt, the BMS will clear the accumulated charging capacity Qchg and QDischg to zero, recalculate Qchg and QDischg, and return to step S1502 to continue the charging and discharging process switching.

[0260] The charging and discharging process described in this application embodiment allows for a short-duration, low-rate discharge step during continuous fast charging of the battery at a high rate. This effectively eliminates the accumulation of lithium ions at the negative electrode, reduces the risk of lithium plating in the battery cell, ensures safe charging, and significantly slows down battery lifespan degradation. Simultaneously, it greatly increases the charging rate, shortening the overall charging time. Furthermore, even at low temperatures, the battery can operate in an alternating charging and discharging mode, avoiding the problem of traditional unidirectional charging requiring preheating of the battery pack before gradually increasing the charging current.

[0261] On the other hand, the charging and discharging device can charge and discharge the battery using only the secondary battery, or it can be further combined with unidirectional or bidirectional AC / DC to charge and discharge the battery through the power grid. It is flexible in configuration and has strong system portability.

[0262] The above text combined Figures 2 to 15 Specific embodiments of the battery charging method provided in this application are illustrated below. Figures 16 to 17 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.

[0263] Figure 16 A schematic structural block diagram of a charging and discharging device provided in an embodiment of this application is shown.

[0264] like Figure 16 As shown, the charging and discharging device 1600 may include a bidirectional DC / DC converter 1610 and a control unit 1620.

[0265] Optionally, the control unit is configured to: receive a first charging current sent by the battery management system (BMS) of the battery, and based on the first charging current, control the bidirectional DC / DC converter to charge the battery through the energy storage battery; receive a first discharging current sent by the BMS, and based on the first discharging current, control the bidirectional DC / DC converter to release the battery's charge into the energy storage battery, wherein the first discharging current is the discharging current sent by the BMS when the battery's first cumulative charge 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; receive a second charging current sent by the BMS, and based on the second charging current, control the bidirectional DC / DC converter to charge the battery through the energy storage battery, wherein the second charging current is the charging current sent by the BMS when the battery's first cumulative discharge is greater than or equal to a first cumulative discharge threshold.

[0266] Optionally, the control unit is further configured to: receive a second discharge current sent by the BMS, and based on the second discharge current, control the bidirectional DC / DC converter to release the battery's charge into the energy storage battery, wherein the second discharge current is the discharge current sent by the BMS when the battery's second cumulative charge is greater than or equal to a second cumulative charge threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell.

[0267] Optionally, the control unit is further configured to: determine, based on the first discharge current, that the discharge power demand of the battery is less than a discharge power threshold; and control the bidirectional DC / DC converter to release the battery's charge into the energy storage battery.

[0268] Optionally, the control unit is further configured to: determine, based on the first discharge current, that the discharge power demand of the battery is greater than or equal to a discharge power threshold; control the bidirectional DC / DC converter to release the first discharge power demand amount to the energy storage battery, and control the bidirectional DC / DC converter to release the second discharge power demand amount to the power grid through a second charging and discharging device, wherein the sum of the first discharge power demand and the second discharge power demand is equal to the discharge power demand.

[0269] Optionally, the control unit is further configured to: acquire the state of charge (SOC) value of the energy storage battery; determine that the SOC is greater than or equal to the state of charge threshold, and control the bidirectional DC / DC converter to charge the battery through the energy storage battery based on the first charging current.

[0270] Optionally, the control unit is further configured to: acquire the state of charge (SOC) value of the energy storage battery; specifically, the control unit is configured to: determine that the SOC is less than a state of charge threshold; send a charging request message to the second charging and discharging device, so that the second charging and discharging device charges the energy storage battery through the power grid; determine that the SOC is greater than or equal to the state of charge threshold, and control the bidirectional DC / DC converter to charge the battery through the energy storage battery based on the first charging current.

[0271] Optionally, the control unit is further configured to: receive a charging stop command sent by the BMS and stop 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.

[0272] Optionally, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0273] Optionally, the discharge rate of the first discharge current is in the range of 0.1C to 1C.

[0274] Optionally, the ratio of the first cumulative discharge threshold to the first cumulative charge threshold is less than or equal to 10%.

[0275] 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.

[0276] Optionally, the control unit is specifically configured to: periodically receive the first charging current sent by the BMS; and / or periodically receive the first discharging current sent by the BMS; and / or periodically receive the second charging current sent by the BMS.

[0277] 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, 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, 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.

[0278] Figure 17 A schematic structural block diagram of a battery management system (BMS) 1700 according to one embodiment of this application is shown. Figure 17 As shown, the BMS 1700 includes: an acquisition unit 1710, a transmission unit 1720, and a processing unit 1630.

[0279] In one embodiment of this application, the acquisition unit is used to acquire a first charging current; the sending unit 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 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 is further used to acquire a first discharging current; the sending unit is further used to send 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; optionally, the processing unit is further used to determine that when the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the acquisition unit is further used to acquire a second charging current; the sending unit 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.

[0280] Optionally, 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 sending unit 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.

[0281] Optionally, 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.

[0282] Optionally, the charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

[0283] Optionally, the discharge rate of the first discharge current and / or the second discharge current ranges from 0.1C to 1C.

[0284] 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%.

[0285] Optionally, the acquisition unit 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 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 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.

[0286] Optionally, the acquisition unit is used to periodically acquire a 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 a first discharging current, and the sending unit is used to periodically send the first discharging current to the charging and discharging device; and / or, the acquisition unit is used to periodically acquire a second charging current, and the sending unit is used to periodically send the second charging current to the charging and discharging device.

[0287] Optionally, 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 (BCL) message; and / or, the acquisition unit is further configured to acquire a first discharging voltage, and the sending unit 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 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 BCL message; and / or, the acquisition unit is further configured to acquire a second discharging voltage, and the sending unit 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.

[0288] Figure 18 A schematic structural block diagram of an electronic device 1800 according to an embodiment of this application is shown. Figure 18 As shown, the electronic device 1800 includes a memory 1810 and a processor 1820, wherein the memory 1810 is used to store a computer program, and the processor 1820 is used to read the computer program and execute the methods of the various embodiments of the present application based on the computer program.

[0289] Optionally, the electronic device 1800 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.

[0290] 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.

[0291] 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.

[0292] 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.

[0293] 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.

[0294] 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 charging and discharging device, characterized in that, include: Bidirectional DC / DC converter and control unit; The control unit is used for: The system receives a first charging current sent by the battery management system (BMS) of the power battery, and controls the bidirectional DC / DC converter to charge the power battery through the energy storage battery based on the first charging current. The system receives a first discharge current sent by the BMS and controls the bidirectional DC / DC converter based on the first discharge current to release the power battery's charge into the energy storage battery. The first discharge current is the discharge current sent by the BMS when the first cumulative charge of the power battery is greater than or equal to a first cumulative charge threshold and the voltage of a single cell of the power battery does not exceed the full charge voltage of the single cell. The control unit is further configured to: Obtain the state of charge (SOC) value of the energy storage battery; It is determined that the SOC is less than the state of charge threshold; The energy storage battery can be charged by a DC power source; or a charging request message can be sent to a second charging and discharging device, so that the second charging and discharging device can charge the energy storage battery through the power grid. The state of charge (SOC) is determined to be greater than or equal to the state of charge threshold, and based on the first charging current, the bidirectional DC / DC converter is controlled to charge the power battery through the energy storage battery.

2. The charging and discharging device according to claim 1, characterized in that, The system receives a second charging current sent by the BMS and controls the bidirectional DC / DC converter to charge the power battery through the energy storage battery based on the second charging current. The second charging current is the charging current sent by the BMS when the first cumulative discharge amount of the power battery is greater than or equal to the first cumulative discharge amount threshold.

3. The charging and discharging device according to claim 2, characterized in that, The control unit is also used for: The system receives a second discharge current sent by the BMS and controls the bidirectional DC / DC converter based on the second discharge current to release the power battery's charge into the energy storage battery. The second discharge current is the discharge current sent by the BMS when the second cumulative charge of the power battery is greater than or equal to a second cumulative charge threshold and the voltage of a single cell of the power battery does not exceed the full charge voltage of the single cell.

4. The charging and discharging device according to any one of claims 1 to 3, characterized in that, The control unit is also used for: Based on the first discharge current, it is determined that the discharge power demand of the power battery is less than the discharge power threshold. Control the bidirectional DC / DC converter to release the power from the power battery into the energy storage battery.

5. The charging and discharging device according to any one of claims 1 to 3, characterized in that, The control unit is also used for: Based on the first discharge current, it is determined that the discharge power demand of the power battery is greater than or equal to the discharge power threshold. The bidirectional DC / DC converter is controlled to release a first discharge demand power to the energy storage battery, and the bidirectional DC / DC converter is also controlled to release a second discharge demand power to the power grid through a second charging and discharging device, wherein the sum of the first discharge demand power and the second discharge demand power is equal to the discharge demand power.

6. The charging and discharging device according to any one of claims 1 to 5, characterized in that, The control unit is also used for: Obtain the state of charge (SOC) value of the energy storage battery; The state of charge (SOC) is determined to be greater than or equal to the state of charge threshold, and based on the first charging current, the bidirectional DC / DC converter is controlled to charge the power battery through the energy storage battery.

7. The charging and discharging device according to any one of claims 1 to 6, characterized in that, The control unit is also used for: Based on the first charging current and / or the second charging current, the bidirectional AC / DC converter and the bidirectional DC / DC converter in the second charging and discharging device are controlled to charge the power battery through the power grid.

8. The charging and discharging device according to any one of claims 1 to 7, characterized in that, The control unit is also used for: The system receives a charging stop command from the BMS and stops charging the power battery. The charging stop command is sent by the BMS when the voltage of a single battery cell exceeds the full charge voltage of that cell.

9. The charging and discharging device according to any one of claims 1 to 8, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

10. The charging and discharging device according to any one of claims 1 to 9, characterized in that, The control unit is specifically used for: Periodically receive the first charging current sent by the BMS; and / or, Periodically receive the first discharge current sent by the BMS; and / or, The system periodically receives the second charging current sent by the BMS.

11. The charging and discharging device according to any one of claims 1 to 10, characterized in that, The control unit is also used for: Receive the first charging voltage sent by the BMS, wherein the first charging voltage and the first charging current are carried in the first battery charging request message; and / or, Receive the first discharge voltage sent by the BMS, wherein the first discharge voltage and the first discharge current are carried in the second battery charging request message; and / or, The second charging voltage sent by the BMS is received, wherein the second charging voltage and the second charging current are carried in the third battery charging demand message.

12. A method for charging a battery, characterized in that, Applied to a charging and discharging device, the method includes: The charging and discharging device receives a first charging current sent by the battery management system (BMS) of the power battery, and controls the bidirectional DC / DC converter in the charging and discharging device to charge the power battery through the energy storage battery based on the first charging current. The charging and discharging device receives a first discharge current sent by the BMS, and controls the bidirectional DC / DC converter based on the first discharge current to release the power battery's charge into the energy storage battery. The first discharge current is the discharge current sent by the BMS when the first cumulative charge of the power 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 acquires the state of charge (SOC) value of the energy storage battery. The charging and discharging device determines that the SOC is less than the state of charge threshold. The charging and discharging device charges the energy storage battery through a DC power supply; or sends a charging request message to the second charging and discharging device, so that the second charging and discharging device charges the energy storage battery through the power grid. The charging and discharging device determines that the SOC is greater than or equal to the state of charge threshold, and controls the bidirectional DC / DC converter to charge the power battery through the energy storage battery based on the first charging current.

13. The method according to claim 12, characterized in that, The method further includes: The charging and discharging device receives a second charging current sent by the BMS, and controls the bidirectional DC / DC converter to charge the power battery through the energy storage battery based on the second charging current. The second charging current is the charging current sent by the BMS when the first cumulative discharge amount of the power battery is greater than or equal to the first cumulative discharge amount threshold.

14. The method according to claim 13, characterized in that, The method further includes: The charging and discharging device receives a second discharge current sent by the BMS, and controls the bidirectional DC / DC converter based on the second discharge current to release the power battery's charge into the energy storage battery. The second discharge current is the discharge current sent by the BMS when the second cumulative charge of the power battery is greater than or equal to a second cumulative charge threshold and the voltage of a single battery cell does not exceed the full charge voltage of the single battery cell.

15. The method according to any one of claims 12 to 14, characterized in that, The charging and discharging device receives a first discharge current sent by the BMS, and based on the first discharge current, controls the bidirectional DC / DC converter to release the power battery's charge into the energy storage battery, including: The charging and discharging device determines, based on the first discharge current, that the discharge power demand of the power battery is less than the discharge power threshold. The charging and discharging device controls the bidirectional DC / DC converter to release the power from the power battery into the energy storage battery.

16. The method according to any one of claims 12 to 14, characterized in that, The charging and discharging device receives a first discharge current sent by the BMS, and based on the first discharge current, controls the bidirectional DC / DC converter to release the power battery's charge into the energy storage battery, including: The charging and discharging device determines, based on the first discharge current, that the discharge power demand of the power battery is greater than or equal to the discharge power threshold. The charging and discharging device controls the bidirectional DC / DC converter to release a first discharge demand power to the energy storage battery, and releases a second discharge demand power to the power grid through the second charging and discharging device, wherein the sum of the first discharge demand power and the second discharge demand power is equal to the discharge demand power.

17. The method according to any one of claims 12 to 16, characterized in that, The method further includes: The charging and discharging device acquires the state of charge (SOC) value of the energy storage battery. The step of controlling the bidirectional DC / DC converter in the charging and discharging device to charge the power battery through the energy storage battery based on the first charging current includes: The charging and discharging device determines that the SOC is greater than or equal to the state of charge threshold, and controls the bidirectional DC / DC converter to charge the power battery through the energy storage battery based on the first charging current.

18. The method according to any one of claims 12 to 17, characterized in that, The method further includes: Based on the first charging current and / or the second charging current, the bidirectional AC / DC converter and the bidirectional DC / DC converter in the second charging and discharging device are controlled to charge the power battery through the power grid.

19. The method according to any one of claims 12 to 18, characterized in that, The method further includes: the charging and discharging device receiving a charging stop command sent by the BMS and stopping charging the power battery, wherein the charging stop command is a command sent by the BMS when the voltage of a single battery cell of the power battery exceeds the full charge voltage of the single battery cell.

20. The method according to any one of claims 12 to 19, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

21. The method according to any one of claims 12 to 20, 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.

22. The method according to any one of claims 12 to 21, 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.

23. A battery system, comprising a power battery and a battery management system (BMS), characterized in that, The BMS includes: an acquisition unit, a transmission unit, and a processing unit; The acquisition unit is used to acquire the first charging current; The transmitting unit is used to send the first charging current to the charging and discharging device, so that the charging and discharging device controls the bidirectional DC / DC converter in the charging and discharging device to charge the power battery through the energy storage battery based on the first charging current. The processing unit is used to determine that the first cumulative charge of the power battery is greater than or equal to the first cumulative charge threshold and the voltage of the battery cell of the power battery does not exceed the full charge voltage of the battery cell. The acquisition unit is further configured 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 bidirectional DC / DC converter based on the first discharge current to release the power battery's charge into the energy storage battery.

24. The battery system according to claim 23, characterized in that, The processing unit is further configured to determine that the first cumulative discharge amount of the power battery is greater than or equal to the first cumulative discharge amount threshold. The acquisition unit is also used to acquire the second charging current; The transmitting unit is further configured to send the second charging current to the charging and discharging device, so that the charging and discharging device controls the bidirectional DC / DC converter to charge the power battery through the energy storage battery based on the second charging current.

25. The battery system according to claim 24, characterized in that, The processing unit is further configured to determine that the second cumulative charge amount of the power battery is greater than or equal to the second cumulative charge amount threshold and that the voltage of the battery cell of the power battery 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 bidirectional DC / DC converter based on the second discharge current to release the power battery's charge into the energy storage battery.

26. The battery system according to any one of claims 23 to 25, characterized in that, The transmitting unit is further configured to transmit the first charging current and / or the second charging current to the charging and discharging device, so that the charging and discharging device controls the bidirectional AC / DC converter in the second charging and discharging device and the bidirectional DC / DC converter to charge the power battery through the power grid.

27. The battery system according to any one of claims 23 to 26, characterized in that, The processing unit is also used to determine that the voltage of a single battery cell in the power battery exceeds the full charge voltage of the single battery cell. The transmitting unit is also used to send a charging stop command to the charging and discharging device so that the charging and discharging device stops charging the power battery.

28. The battery system according to any one of claims 23 to 27, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

29. The battery system according to any one of claims 23 to 28, characterized in that, The acquisition unit is specifically used to periodically acquire the first charging current, and the sending unit is specifically used to periodically send the first charging current to the charging and discharging device; and / or, The acquisition unit is specifically used to periodically acquire the first discharge current, and the sending unit is specifically used to periodically send the first discharge current to the charging and discharging device; and / or, The acquisition unit is specifically used to periodically acquire the second charging current, and the sending unit is specifically used to periodically send the second charging current to the charging and discharging device.

30. The battery system according to any one of claims 23 to 29, 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 (BCL) 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 BCL 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 BCL message; and / or, The acquisition unit is further configured to acquire a second discharge voltage, and the sending unit is further configured to send the second discharge voltage to the charging and discharging device, wherein the second discharge current and the second discharge voltage are carried in a fourth BCL message.

31. A method applied to a battery management system (BMS), characterized in that, The method includes: Obtain the first charging current; The first charging current is sent to the charging and discharging device so that the charging and discharging device controls the bidirectional DC / DC converter in the charging and discharging device to charge the power battery through the energy storage battery based on the first charging current. When the first cumulative charge of the power battery is determined to be 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 first discharge current is obtained. The first discharge current is sent to the charging and discharging device so that the charging and discharging device controls the bidirectional DC / DC converter based on the first discharge current to release the power battery into the energy storage battery.

32. The method according to claim 31, characterized in that, The method further includes: When the first cumulative discharge amount of the power battery is determined to be greater than or equal to the first cumulative discharge threshold, the second charging current is obtained; The second charging current is sent to the charging and discharging device so that the charging and discharging device controls the bidirectional DC / DC converter to charge the power battery through the energy storage battery based on the second charging current.

33. The method according to claim 32, characterized in that, The method further includes: When the second cumulative charge of the power battery is determined to be greater than or equal to the second cumulative charge threshold and the voltage of the battery cell of the power battery does not exceed the full charge voltage of the battery cell, the second discharge current is obtained. The second discharge current is sent to the charging and discharging device so that the charging and discharging device controls the bidirectional DC / DC converter based on the second discharge current to release the power battery into the energy storage battery.

34. The method according to any one of claims 31 to 33, characterized in that, The method further includes: The first charging current and / or the second charging current are sent to the charging and discharging device so that the charging and discharging device controls the bidirectional AC / DC converter in the second charging and discharging device and the bidirectional DC / DC converter to charge the power battery through the power grid.

35. The method according to any one of claims 31 to 34, characterized in that, The method further includes: When it is determined that the voltage of a single battery cell in the power battery exceeds the full charge voltage of the single battery cell, a charging stop command is sent to the charging and discharging device to stop the charging and discharging device from charging the power battery.

36. The method according to any one of claims 31 to 35, characterized in that, The charging rate of the first charging current and / or the second charging current ranges from 2C to 10C.

37. The method according to any one of claims 31 to 36, characterized in that, The process of obtaining the first charging current includes: Periodically acquire the first charging current and periodically send the first charging current to the charging and discharging device; and / or, The acquisition of the first discharge current includes: Periodically acquire the first discharge current and periodically send the first discharge current to the charging and discharging device; and / or, The process of obtaining the second charging current includes: The second charging current is periodically acquired and periodically sent to the charging and discharging device.

38. The method according to any one of claims 31 to 37, characterized in that, The method further includes: Acquire a first charging voltage and 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 request (BCL) message; and / or, Acquire a first discharge voltage and send the first discharge voltage to the charging / discharging device, wherein the first discharge current and the first discharge voltage are carried in a second BCL message; and / or, Acquire a second charging voltage and 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 second discharge voltage is acquired and sent to the charging and discharging device, wherein the second discharge current and the second discharge voltage are carried in the fourth BCL message.

39. A charging and discharging device, characterized in that, include: A processor and a memory, the memory being used to store a computer program, the processor being used to invoke the computer program to perform a battery charging method as described in any one of claims 12 to 22.

40. A system, characterized in that, include: The battery system according to any one of claims 23 to 30, and the charging and discharging device according to any one of claims 1 to 11.

41. The system according to claim 40, characterized in that, It also includes the energy storage battery.

42. The system according to claim 40 or 41, characterized in that, It also includes a second charging and discharging device.

43. An electric vehicle, characterized in that, include: The battery system as described in any one of claims 23 to 30.

44. A system, characterized in that, include: The electric vehicle as claimed in claim 43, and the charging and discharging device as claimed in any one of claims 1 to 11.

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