Charging and discharging control method, device and equipment, and storage medium

Abstract

Embodiments of the present application provide a charging and discharging control method, device, equipment and storage medium. The method is applied to a charging system, the charging system includes at least two charging devices, the at least two charging devices are connected with batteries respectively, and the method includes the following steps. When at least one of the at least two batteries requests discharging, the discharging path of the battery requesting discharging is determined according to the charging and discharging parameters of the currently connected battery. The application autonomously controls the discharging path according to the charging and discharging parameters of the battery, which helps to shorten the discharging path, so that the electric quantity discharged by the battery requesting discharging at the same time can be directly charged into the battery requesting charging through the DC bus, the conversion path of the part of electric quantity is very short, the charging efficiency is improved, the electric quantity loss is reduced by shortening the discharging path, energy is saved, and the charging cost increased due to the electric quantity loss is reduced. In addition, the polarization problem of lithium and the battery is relieved through discharging, the charging safety is improved, the charging rate is also improved, and the effect of safe fast charging is realized.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a charging and discharging control method, apparatus, device, and storage medium. Background Technology

[0002] During the charging process of a lithium-ion battery, lithium ions migrate from the positive electrode to the negative electrode. As the charging process continues, lithium ions accumulate at the negative electrode. This limits the charging current on the one hand, and continuous charging with a large current can easily cause lithium plating in the cell, shortening the battery's lifespan and even causing safety issues.

[0003] Currently, related technologies incorporate low-rate discharge during high-rate charging to alleviate the lithium plating problem in battery cells. However, in these technologies, the current released by the battery is fed back into the power grid, and then recharged during the charging phase. This results in a long current path for the released energy, leading to low charging efficiency, energy loss, and increased charging costs. Summary of the Invention

[0004] This application provides a charging and discharging control method, apparatus, device, and storage medium. When a charging system establishes charging and discharging connections with multiple batteries simultaneously, it can automatically determine the discharge path of the battery requesting discharge based on the charging and discharging parameters of the connected batteries when a battery is discharging. This enables autonomous control of the discharge path, thereby helping to shorten the battery's discharge path and improve charging efficiency.

[0005] In a first aspect, embodiments of this application provide a charging and discharging control method applied to a charging system, the charging system including at least two charging devices, each of the at least two charging devices being connected to a battery, the method including:

[0006] When at least one of the at least two batteries requests discharge, the discharge path of the battery requesting discharge is determined based on the charge and discharge parameters of the currently connected battery.

[0007] In this embodiment, when the charging system is connected to multiple batteries, when at least one battery requests to discharge, the discharge path of the battery requesting discharge is automatically determined based on the battery's charging and discharging parameters, thereby achieving autonomous control of the discharge path. This helps to shorten the battery's discharge path, improve charging efficiency, reduce power loss, save energy, and reduce the increased battery charging cost due to power loss.

[0008] In some embodiments of this application, determining the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected battery includes:

[0009] Based on the charging and discharging parameters of each currently connected battery and preset power conditions, the discharge path of the battery requesting discharge is determined; the preset power conditions include that the total charging power of all currently connected batteries is greater than or equal to the total discharging power.

[0010] In this embodiment, since the electrical energy released by the battery requesting discharge can only be charged to the battery requesting charging via the DC bus when the total charging power is greater than or equal to the total discharging power, without needing to be fed back into the grid, the total charging power being greater than or equal to the total discharging power is used as a preset power condition. Determining the discharge path of the battery requesting discharge based on the battery's charging and discharging parameters and this preset power condition helps to determine a discharge path that directly charges the battery requesting charging via the DC bus. This reduces the possibility of the discharge path including flow to the grid or the energy storage device of the charging system, shortens the battery's discharge path, improves charging efficiency, and reduces energy loss caused by the released energy flowing through this discharge path, saving energy and reducing the charging cost of electrical equipment.

[0011] In some embodiments of this application, determining the discharge path of the battery requesting discharge based on the charging and discharging parameters of each currently connected battery and preset power conditions includes:

[0012] Based on the charging and discharging parameters of each currently connected battery, determine whether the preset power conditions are met.

[0013] If so, the discharge path of the battery requesting discharge is determined to be from the battery requesting discharge to the battery requesting charging via the DC bus.

[0014] If not, the battery requesting discharge will pause its discharge.

[0015] In this embodiment, if the preset power condition is met, meaning the total charging power of all batteries is greater than or equal to the total discharging power, it indicates that the amount of electricity released by the battery requesting discharge can be fully received by the battery requesting charging. Therefore, the discharge path is determined to be from the battery requesting discharge to the battery requesting charging via the DC bus. The battery requesting discharge is controlled to discharge according to this path. In this case, the released electricity does not need to be fed back to the grid or stored in the energy storage device of the charging system. The discharge path is short, improving charging efficiency and avoiding power loss caused by an excessively long discharge path. However, if the current total charging power is determined to be less than the total discharging power, it indicates that if the battery requesting discharge discharges, the released electricity cannot be fully received by the battery requesting charging, resulting in redundant electricity. This redundant electricity needs to be fed back to the grid or stored in the energy storage device of the charging system, leading to an excessively long discharge path. To reduce this situation, this embodiment controls the battery requesting discharge to pause discharging when the preset power condition is not met, so that the battery can be controlled to discharge again when the preset power condition is met later, thereby shortening its discharge path.

[0016] In some embodiments of this application, after the battery requesting discharge is paused, the following steps are further included:

[0017] Periodically determine whether the preset power condition is met within a preset time period; or,

[0018] Within a preset time period, whenever a battery is detected switching from a discharging state to a charging state, it is determined whether the preset power condition is currently met.

[0019] In this embodiment, periodically determining whether a preset power condition is met helps to promptly control the paused battery discharge when the condition is met, avoiding excessively long pauses in battery discharge. Alternatively, when a battery switches to a charging state, the total amount of charging power that the entire system can accept increases, making it more likely that the preset power condition will be met. This reduces the number of repeated checks and saves computing resources for the charging equipment.

[0020] In some embodiments of this application, the method further includes:

[0021] If the preset power condition is still not met when the duration of the paused discharge of the requested battery reaches the preset duration, then the discharge path is determined to be from the requested battery to the power grid and / or the energy storage device in the charging system.

[0022] In this embodiment, if the preset power condition is not met when the discharge pause duration reaches the preset duration, the battery is directly controlled to release electrical energy into the grid and / or the energy storage device of the charging system. This can prevent the battery from being in a pause state for a long time and avoid the total charging time of the battery from being too long.

[0023] In some embodiments of this application, determining whether a preset power condition is met based on the charging and discharging parameters of each currently connected battery includes:

[0024] Calculate the total discharge power of all currently connected batteries based on the discharge parameters of the current discharging battery and the discharge request parameters of the battery currently requesting discharge.

[0025] Calculate the total charging power of all currently connected batteries based on the charging parameters of the current battery.

[0026] Based on the total charging power and the total discharging power, determine whether the preset power condition is currently met.

[0027] In this embodiment, based on the charging and discharging parameters of each currently connected battery, the total charging power and total discharging power of all currently connected batteries can be quantitatively calculated. Based on the calculated total charging power and total discharging power, it can be accurately determined whether the preset power conditions are met, and thus accurately determine the discharge path of the battery currently requesting discharge.

[0028] In some embodiments of this application, calculating the total discharge power of all currently connected batteries based on the discharge parameters of the current discharging battery and the discharge request parameters of the battery currently requesting discharge includes:

[0029] Calculate the discharge power of all currently discharging batteries based on their discharge parameters.

[0030] Calculate the requested discharge power of the battery currently requesting discharge based on its discharge request parameters.

[0031] Calculate the sum of the discharge power of all currently discharged batteries and the requested discharge power to obtain the total discharge power of all currently connected batteries.

[0032] In this embodiment, both the battery currently in the discharge phase and the battery currently requesting discharge are taken into account, making the final calculated total discharge power more accurate and improving the accuracy of subsequent judgments on whether the current preset power conditions are met, thereby enabling a more accurate determination of the battery's discharge path.

[0033] In some embodiments of this application, if there are multiple batteries to be discharged, including those currently paused and those currently requesting discharge, the total discharge power of all currently connected batteries is calculated based on the discharge parameters of the currently discharging battery and the discharge request parameters of the currently requesting battery, including:

[0034] Determine a complete combination of multiple said batteries to be discharged, wherein each combination includes at least one battery to be discharged;

[0035] Calculate the discharge power of each current discharge battery based on its discharge parameters; calculate the requested discharge power of each battery in each combination based on its discharge parameters.

[0036] Calculate the total discharge power for each combination based on the discharge power of all currently discharging batteries and the requested discharge power of the batteries to be discharged in each combination.

[0037] In this embodiment, when there are multiple batteries to be discharged, the total discharge power corresponding to each combination of these batteries is calculated. This allows for subsequent determination of whether each combination meets the preset power conditions, making charge and discharge control more flexible and helping to find the optimal combination for charge and discharge control.

[0038] In some embodiments of this application, determining whether a preset power condition is currently met based on the total charging power and the total discharging power includes:

[0039] Determine whether there exists a combination in each combination whose total discharge power is less than or equal to the total charging power;

[0040] If it exists, then it is determined that the preset power condition is currently met.

[0041] In this embodiment, when there are multiple batteries to be discharged, the entire combination of these batteries is determined, and each combination is judged on a unit basis to determine whether it meets the preset power conditions. This allows for the determination of whether one or more batteries to be discharged can be allowed to discharge based on the control of the total charging power and the total discharging power, making the control process in the case of multiple batteries to be discharged more flexible and efficient.

[0042] In some embodiments of this application, the method further includes:

[0043] If it is determined that there exists a combination where the total discharge power is less than or equal to the current total charging power, then the batteries in the determined combination are controlled to discharge; or,

[0044] If it is determined that there are multiple combinations where the total discharge power is less than or equal to the total charging power, then the target combination containing the largest number of batteries to be discharged is determined from the multiple combinations; if one target combination is determined, then each battery to be discharged in the target combination is controlled to discharge; if multiple target combinations are determined, then the target combination with the longest pause in battery discharge is selected from the multiple target combinations, and each battery to be discharged in the selected target combination is controlled to discharge.

[0045] In this embodiment, when multiple candidate combinations are identified, the combination containing the largest number of batteries to be discharged is selected. This allows for the control of more batteries to discharge, shortening the total charging time for these batteries. When multiple combinations contain the largest number of batteries to be discharged, the duration of the discharge pause for each battery in these combinations is determined. The battery with the longest pause duration is identified, and the discharge of each battery in the combination containing that battery is controlled. This ensures that the battery with the longest pause duration resumes discharge, avoiding excessively long waiting times for that battery.

[0046] In some embodiments of this application, the control of the battery requesting discharge to pause discharge includes:

[0047] The output voltage of the charging device connected to the battery requesting discharge is set to the current voltage of the battery requesting discharge; or,

[0048] The charging device connected to the battery that is requesting discharge will suspend its output.

[0049] In this embodiment, when the total charging power is less than the total discharging power, the battery requesting discharge is controlled to pause discharging, thus avoiding redundant power that cannot be accepted by the battery in the charging stage in the entire charging system. The control process is simple and efficient by controlling the charging device connected to the battery to pause output or output current to zero.

[0050] In some embodiments of this application, the method further includes:

[0051] If the charging system establishes charging and discharging connections with multiple batteries at the same time, it controls the charging devices connected to the multiple batteries to start charging functions sequentially.

[0052] In other words, although these multiple batteries establish charging and discharging connections with the charging system at the same time, the charging system controls the charging devices connected to each battery to start in a certain time sequence, so that the actual charging process of these multiple batteries starts sequentially. This makes the discharging stages of these multiple batteries not completely synchronized, reducing the possibility of the total charging power being less than the total discharging power, making the subsequent control process smoother, reducing control complexity, and improving charging efficiency.

[0053] Secondly, embodiments of this application provide a charge / discharge control device applied to a charging system, the charging system including at least two charging devices, each of which is connected to a battery, the device comprising:

[0054] A discharge path determination module is used to determine the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected battery when at least one of the at least two batteries requests discharge.

[0055] Thirdly, embodiments of this application provide a charging system, including: a control unit, a power converter, a DC bus, and multiple charging devices;

[0056] The power converter is connected to the power grid and the DC bus, respectively.

[0057] The plurality of charging devices are all connected to the DC bus, and each of the charging devices is used to connect to the battery;

[0058] The control unit is used to perform the method described in the first aspect above.

[0059] In some embodiments of this application, an energy storage device and its corresponding voltage converter are also included;

[0060] The energy storage device is connected to the DC bus via its corresponding voltage converter.

[0061] Fourthly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the method described in the first aspect.

[0062] Fifthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the first aspect.

[0063] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0064] 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.

[0065] Figure 1 This is a current waveform diagram showing an added discharge phase during the charging process provided in one embodiment of this application.

[0066] Figure 2 This is a schematic diagram of a charging system provided in one embodiment of this application.

[0067] Figure 3 This is a schematic diagram of another charging system provided in an embodiment of this application.

[0068] Figure 4 This is a schematic flowchart of a charging and discharging control method provided in an embodiment of this application.

[0069] Figure 5 This is a current waveform diagram of vehicle 1, vehicle 2 and vehicle n during the charging process provided in the embodiments of this application;

[0070] Figure 6 This is a schematic diagram of the structure of a charge and discharge control device provided in an embodiment of this application.

[0071] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0072] 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.

[0073] 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," and "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," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0074] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0075] Currently, batteries are widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. In electric transportation, military equipment, and aerospace, batteries are typically used to provide power. However, the most criticized aspect of battery-powered devices is their long charging time, which significantly limits public acceptance of such devices (e.g., electric vehicles). Improving charging speed and shortening charging time has become a crucial challenge that must be overcome in the development of these devices.

[0076] To improve charging speed and shorten charging time, existing technologies primarily rely on unidirectional charging devices (such as unidirectional charging stations). This involves simultaneously increasing the output power of the unidirectional DC charging device and the battery's maximum allowable continuous charging current. Typically, batteries are power-type cells. Improving the cell's low-temperature performance, combined with increasing the power of the DC charging device, allows the Battery Management System (BMS) to request the maximum charging current from the charging device when the battery temperature reaches the cell's optimal charging temperature, thus achieving super-fast charging.

[0077] However, lithium-ion batteries are commonly used in current batteries. From a microscopic perspective, during charging, lithium ions migrate from the positive electrode to the negative electrode and embed themselves into the negative electrode material, completing the charging process. Increasing charging speed means accelerating the migration and embedding speed of lithium ions. During continuous high-rate unidirectional charging, lithium ions accumulate at the negative electrode. This limits the charging current and, more importantly, continuous high-current charging can easily cause lithium plating within the cell, reducing the thermal stability of the negative electrode. Furthermore, the formed lithium dendrites may pierce the separator, causing a short circuit between the positive and negative electrodes, reducing the battery's lifespan, and even inducing serious safety issues such as thermal runaway. Therefore, during the aforementioned rapid charging process, the cumulative effect of lithium ions at the negative electrode cannot be eliminated in time, thus limiting the potential increase in charging speed.

[0078] In researching how to alleviate the problem of lithium-ion accumulation at the negative electrode during charging, it was discovered that related technologies can eliminate lithium-ion accumulation at the negative electrode of the lithium battery by adding a short-term discharge process during charging. For example... Figure 1 As shown, during the charging process, the charging current and discharging current switch back and forth. Within one charging cycle, the charging current is ReqChgI1, and the cumulative charging capacity is >= Q11. Then, it switches to the discharging state, with the discharging current being ReqDischgI1, and the cumulative discharging capacity >= Q21. This charging and discharging process repeats, and the magnitude and duration of the charging current ReqChgI1 and discharging current ReqDischgI1 are dynamically adjusted according to the battery state. The cumulative charging capacity in each cycle is greater than the cumulative discharging capacity. The discharging current within a cycle can be less than the charging current, or greater than or equal to the charging current. The discharging duration within a cycle is less than the charging duration.

[0079] By adding a low-rate discharge process during high-rate charging, the problem of lithium-ion accumulation on the negative electrode is effectively eliminated, the battery polarization phenomenon is weakened or even eliminated, the safety of battery charging is improved, and the charging rate of the battery is increased, thus achieving the goal of safe and fast battery charging.

[0080] When using the aforementioned method of adding a discharge phase during charging for fast charging, a charging device capable of both charging and discharging is required. This charging device needs to be able to release the energy discharged from the battery into the power grid or an energy storage device within the charging system. In charging system applications such as charging stations or battery swapping stations, multiple devices are typically charged simultaneously, with each device establishing a charging / discharging connection with a separate charging device. The inventors discovered that when the charging system simultaneously fast charges the batteries of multiple devices, the energy discharged by each device's battery during the discharge phase is released into the power grid or an energy storage device within the charging system. During the charging phase, the energy is then transferred from the power grid or energy storage device back into the device's battery. Therefore, the path for this portion of the energy released from the battery to be recharged back into the battery is too long, resulting in low charging efficiency and increased energy loss throughout the process. This lost energy cost is borne by the user, increasing the cost of using the device.

[0081] Based on this, the inventors of this application have designed a charging and discharging control method through in-depth research. In this method, the charging system includes at least two charging devices, which are respectively connected to the battery for charging and discharging. When at least one of the at least two batteries requests to discharge, the discharge path of the battery requesting to discharge is determined according to the charging and discharging parameters of the currently connected battery.

[0082] When a charging system connects multiple batteries, when at least one battery requests to discharge, the discharge path of the requesting battery is automatically determined based on the battery's charging and discharging parameters. This enables autonomous control of the discharge path, which helps to shorten the battery's discharge path, improve charging efficiency, reduce power loss, save energy, and reduce the increased battery charging costs due to power loss.

[0083] The charging and discharging control method provided in this application can be applied to any charging system capable of both charging and discharging batteries, and the charging system includes at least two charging devices. The charging system can be a battery swapping station, a charging station, or a photovoltaic energy storage system, etc., and the charging devices can be charging piles, charging / discharging machines, chargers, etc. The battery used for charging by this system can be a single cell, or a battery pack or battery stack composed of multiple single cells. The charging system can use the method improved in this application to charge and discharge the battery of any electrical device, which can be, but is not limited to, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc., that have batteries. Electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0084] The charging system in this embodiment can maintain charging and discharging connections with multiple batteries simultaneously, thereby charging or discharging multiple batteries at the same time. The charging system may include a control unit, a power converter, a DC bus, and multiple charging devices. The power converter is connected to both the power grid and the DC bus, the multiple charging devices are all connected to the DC bus, and the control unit is connected to both the power converter and the multiple charging devices.

[0085] A power converter can be an AC / DC (alternating current / direct current) converter, used to convert AC power from the power grid into DC power. The DC side of the power converter is called the DC bus. After converting the AC power from the power grid to DC power, the voltage converter conducts the DC power to the DC bus.

[0086] The charging device can be a voltage converter, such as a DC / DC converter, used to convert electrical energy of one voltage value to electrical energy of another voltage value in a DC circuit. In the charging system of this application embodiment, the above-mentioned charging device is used to charge the battery by reducing or increasing the voltage of the DC bus, or to release the electrical energy of the battery to the DC bus.

[0087] The control unit can be the processor of the charging system, or it can be composed of multiple controllers with smaller functions; this is not limited here. The control unit is connected to the power converter and is used to control the power converter to activate the rectification function to convert the AC power from the grid into DC power to charge the battery. Alternatively, the control unit is used to control the power converter to activate the inverter function to convert the DC power on the DC bus side into AC power to release the electrical energy released by the battery into the grid. The control unit is also connected to each charging device. In practical applications, the charging device is used to connect to the battery in the electrical appliance. The control unit controls the charging device to adjust the voltage on the DC bus side to charge the battery with electrical energy from the DC bus side, or to release the electrical energy discharged from the battery back to the DC bus.

[0088] In other embodiments, the charging system further includes an energy storage device and a voltage converter connected to the energy storage device. The energy storage device is connected to a DC bus via the voltage converter, and a control unit is also connected to the voltage converter. The control unit controls the voltage converter to adjust the voltage to store the electrical energy released from the battery onto the DC bus into the energy storage device, or to charge the battery with the electrical energy from the energy storage device via the DC bus. The energy storage device can be a battery or a photovoltaic panel, etc.

[0089] It should be noted that the energy storage device and the voltage converter connected between the energy storage device and the DC bus are not necessary. If the current converter supports bidirectional power flow, that is, it can both rectify AC power into DC power and invert DC power into AC power to feed back to the grid, then the charging system can be equipped with an energy storage device and its corresponding voltage converter, or it can be omitted.

[0090] To facilitate understanding of the structure of the charging system described above, a specific example is provided below with reference to the accompanying drawings. In this example, the electrical equipment used is an electric vehicle. Figure 2 As shown, the charging system includes a control unit, an AC / DC power converter, a DC bus, charging devices DC / DC-1, DC / DC-2...DC / DC-n, and a voltage converter DC / DC connected to both the energy storage battery and the DC bus. DC / DC-1, DC / DC-2...DC / DC-n are all used to connect to the battery of the electric vehicle. Figure 2 The dashed lines in the diagram show the connections of the control unit to AC / DC, DC / DC-1, DC / DC-2...DC / DC-n, the energy storage battery, and the corresponding DC / DC converter for the energy storage battery.

[0091] In one operating scenario of the charging system, there is only one electric vehicle to be charged, and it is assumed that this electric vehicle is connected to a DC / DC converter for charging. At the beginning of charging, the DC / DC converter transforms the electrical energy from the DC bus and outputs DC power according to the requirements of the electric vehicle's BMS. When the energy accumulated in the battery reaches the upper limit threshold W1, a rapid switching request for a certain discharge current is initiated. At this time, the DC / DC converter switches to discharge mode, and the AC / DC converter and / or the DC / DC converter connected to the energy storage battery also switch to discharge mode to release the energy released from the electric vehicle's battery into the grid, and / or to store the released energy in the energy storage battery. By adding a discharge stage during the charging process, the accumulation of lithium ions at the negative electrode of the battery is reduced, alleviating lithium plating caused by lithium ion aggregation. This allows for high-rate charging without compromising battery life, achieving super-fast charging.

[0092] In another operating scenario of the charging system, there are multiple electric vehicles waiting to be charged, each connected to a separate DC / DC converter. For example... Figure 2As shown, there are vehicles 1, 2, ..., n, where DC / DC-1 is connected to vehicle 1, DC / DC-2 is connected to vehicle 2, and DC / DC-n is connected to vehicle n. The charging equipment performs fast charging on all vehicles, combining high-rate charging with low-rate discharging during the fast charging process. If the total discharge power of all vehicles in the circuit is greater than the total charging power, the excess electricity δW needs to be fed back to the grid via AC / DC or charged into the energy storage battery via DC / DC connected to the energy storage battery. When the charging power exceeds the discharging power in the next stage, additional electricity needs to be obtained from the grid. Taking the electricity released by the battery of vehicle 1 as an example, the overall conversion path of this electricity is: vehicle 1 battery -> DC / DC1 -> AC / DC -> grid -> AC / DC -> DC / DC1 -> vehicle 1 battery, or, vehicle 1 battery -> DC / DC1 -> energy storage battery corresponding DC / DC -> energy storage battery -> energy storage battery corresponding DC / DC -> DC / DC1 -> vehicle 1 battery. The electrical energy undergoes multiple transformations, resulting in low conversion efficiency. In this scenario, the lost electricity will ultimately be borne by the car owner, increasing the cost of car ownership.

[0093] In this embodiment of the application, in an application scenario where the charging system simultaneously connects to multiple electric vehicles, when the charging system receives a discharge request from at least one battery, it determines the discharge path of the requesting battery based on the charging and discharging parameters of the currently connected battery, thereby automatically controlling the discharge path and helping to shorten the discharge path. Taking the discharge of battery power from vehicle 1 as an example, when vehicle 1 needs to discharge to the charging system, the discharge path of vehicle 1's battery is determined based on the charging and discharging parameters of the currently connected battery, ensuring that the discharged energy is directly fed into another vehicle m that is currently charging via the DC bus. The conversion path for the energy released by vehicle 1 is: vehicle 1's battery -> DC / DC1 -> DC bus -> DC / DCm -> vehicle m's battery.

[0094] In photovoltaic energy storage application scenarios, the electrical equipment used will be illustrated using an energy storage cabinet as an example. For example... Figure 3 As shown, the charging system includes a control unit, an AC / DC power converter, a DC bus, charging devices DC / DC-1, DC / DC-2...DC / DC-n, and a voltage converter MPPT (maximum power tracker) connected to the photovoltaic panel and the DC bus. DC / DC-1, DC / DC-2...DC / DC-n are all used to connect to the batteries in the energy storage cabinet. Figure 3 The dashed lines in the diagram show the connection of the control unit to AC / DC, DC / DC-1, DC / DC-2...DC / DC-n, the photovoltaic panel, and the MPPT corresponding to the photovoltaic panel.

[0095] like Figure 3 As shown, there are energy storage cabinets 1, 2, ..., n, where DC / DC-1 is connected to energy storage cabinet 1, DC / DC-2 is connected to energy storage cabinet 2, and DC / DC-n is connected to energy storage cabinet n. DC / DC-1, DC / DC-2, ..., DC / DC-n charge and discharge energy storage cabinets 1, 2, ..., n respectively. Taking the amount of electricity released by the battery in energy storage cabinet 1 as an example, when energy storage cabinet 1 needs to discharge to the charging system, the discharge path of the battery in energy storage cabinet 1 is determined according to the charging and discharging parameters of the currently connected battery, so that the released electricity is directly charged into another energy storage cabinet m that is currently charging after passing through the DC bus. The conversion path of the electricity released by energy storage cabinet 1 is: battery in energy storage cabinet 1 -> DC / DC1 -> DC bus -> DC / DCm -> battery in energy storage cabinet m.

[0096] Based on the above combination Figure 2 and 3 As can be seen from the examples, the embodiments of this application autonomously determine the discharge path based on the battery's charging and discharging parameters, which can shorten the energy conversion path, resulting in high conversion efficiency, low power loss, and no additional cost burden on users. It can eliminate the accumulation of lithium ions on the negative electrode through discharge, weaken or even eliminate battery polarization, improve charging safety, and also help increase the battery's charging rate and efficiency, achieving safe and fast charging.

[0097] This application provides a charge / discharge control method applied to a charging system. The charging system includes at least two charging devices, each for connection to a battery. When the charging system simultaneously establishes charge / discharge connections with multiple batteries, see [link to relevant documentation]. Figure 4 The flowchart shown illustrates a charging and discharging control method, which specifically includes the following steps:

[0098] Step 101: Determine at least one of the at least two currently connected batteries that requests discharge.

[0099] The execution subject of this application embodiment is a charging system, which can be implemented by a control unit included in the charging system. The charging device in the charging system can be a device that can both charge the battery and receive battery discharge.

[0100] When the battery of an electrical device needs charging, the charging gun of the charging device is plugged into the charging port of the electrical device. The control module of the electrical device detects the insertion of the charging gun and controls the battery to enter fast charging mode with high voltage. Entering high voltage means closing the main positive and main negative relays of the battery, thus activating the charging circuit containing the battery. The control module of the electrical device also establishes a communication connection with the charging device. In this embodiment, the charging system can simultaneously establish charging and discharging connections between the batteries of multiple electrical devices using at least two charging devices.

[0101] Among them, charge-discharge connection is used to indicate the connection between the charging device and the battery, which can both charge and discharge the battery.

[0102] After the battery of the electrical device establishes a charging / discharging connection with the charging device and establishes a communication connection with the charging device, the control module of the electrical device determines the requested charging current and requested charging voltage that the battery can currently accept, and sends a charging request to the charging device. This charging request includes the battery's current voltage, the requested charging current, and the requested charging voltage. Based on the charging request sent by the electrical device, the charging device charges the battery of the electrical device using the requested charging current and requested charging voltage included in the charging request.

[0103] After the charging device charges the device for a period of time, the device's control module switches the battery from a charging state to a discharging state. At this time, the device sends a discharge request to the charging device. Since the battery switching from a charging state to a discharging state is controlled by the device's control module, the charging device cannot predict in advance when the device's battery will need to discharge. Therefore, upon receiving a discharge request from at least one battery, the following step 102 is used to determine the discharge path of the requested battery.

[0104] Step 102: Determine the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected battery.

[0105] In this embodiment of the application, a preset power condition is pre-configured in the control unit of the charging system. This preset power condition includes that the total charging power of all currently connected batteries is greater than or equal to the total discharging power. Based on the charging and discharging parameters of each currently connected battery and the preset power condition, the discharge path of the battery requesting discharge is determined. The discharge path refers to the path that the current flows through as the battery discharges and travels from the battery to the target.

[0106] Since only when the total charging power is greater than or equal to the total discharging power can the electrical energy released by the battery requesting discharge be charged to the battery requesting charging via the DC bus, without needing to be fed back into the grid, setting the total charging power to be greater than or equal to the total discharging power as a preset power condition, and determining the discharge path of the battery requesting discharge based on the battery's charging and discharging parameters and this preset power condition, helps to determine the discharge path that directly charges the battery requesting charging via the DC bus. This reduces the possibility of the discharge path including flow to the grid or energy storage devices in the charging system, shortens the battery's discharge path, improves charging efficiency, and reduces the energy loss caused by the released energy flowing through this discharge path, saving energy and reducing the charging cost of electrical equipment.

[0107] Specifically, based on the charging and discharging parameters of each currently connected battery, it is determined whether the preset power conditions are met. If so, the discharge path of the battery requesting discharge is determined to be from the battery requesting discharge to the battery requesting charging via the DC bus. If not, the battery requesting discharge is controlled to pause discharging.

[0108] If the current preset power condition is met, meaning the total charging power of all batteries is greater than or equal to the total discharging power, it indicates that the amount of electricity released by the battery requesting discharge can be fully received by the battery requesting charging. Therefore, the discharge path is determined to be from the battery requesting discharge to the battery requesting charging via the DC bus. The battery requesting discharge is controlled to discharge according to this path. In this case, the released electricity does not need to be fed back to the grid or stored in the energy storage device of the charging system. The discharge path is very short, improving charging efficiency and avoiding power loss caused by an excessively long discharge path. However, if the current total charging power is determined to be less than the total discharging power, it indicates that if the battery requesting discharge discharges, the released electricity cannot be fully received by the battery requesting charging, resulting in redundant electricity. This redundant electricity needs to be fed back to the grid or stored in the energy storage device of the charging system, which would lead to an excessively long discharge path. To reduce this situation, in this embodiment, when it is determined that the preset power condition is not met, the battery requesting discharge is controlled to pause discharging first, so that the battery can be controlled to discharge again when the preset power condition is met later, thereby shortening its discharge path.

[0109] In this embodiment, when the battery requesting discharge is paused, the duration of the paused discharge is also recorded. A preset duration is pre-configured in the control unit of the charging system; this preset duration is the maximum allowed duration for the battery to pause discharge, and can be 4 minutes, 5 minutes, or 6 minutes, etc.

[0110] If the battery requesting discharge is paused, as one implementation method, it is periodically determined whether the preset power condition is met within a preset time period. The duration of one cycle can be 0.2s, 0.5s, or 1s, etc. The determination process for each cycle is the same as the determination process for whether the preset power condition is met, and will not be repeated here. Periodically determining whether the preset power condition is met helps to control the paused battery discharge in a timely manner when the condition is met, avoiding the battery discharge pause time being too long.

[0111] Alternatively, as another implementation, within a preset time period, whenever a battery is detected switching from a discharging state to a charging state, it is determined whether the preset power condition is met. Since the amount of charging power that the entire system can accept increases when a battery switches to a charging state, it is more likely that the preset power condition will be met, reducing the number of repeated checks and saving the computing resources of the charging equipment.

[0112] In some embodiments, the charging device compares the duration of the battery pause with a preset duration at regular intervals. If the battery pause duration is less than the preset duration, the battery continues to be paused from discharging, and the device determines whether the preset power condition is met as described above. If the battery pause duration reaches the preset duration but the preset power condition is still not met, the discharge path is determined to be from the battery requesting discharge to the power grid and / or the energy storage device in the charging system, and the battery is controlled to discharge according to the determined discharge path.

[0113] If the preset power condition is not met even after the preset discharge duration has elapsed, the battery will be directly controlled to release electrical energy into the grid and / or the energy storage device of the charging system. This will prevent the battery from being in a paused state for a long time and avoid the total charging time of the battery from being too long.

[0114] If the battery's discharge pause duration does not meet the preset power requirements after a preset time, the charging system activates the discharge function of the charging equipment connected to the battery. Based on the battery's discharge request parameters, including the requested discharge current and voltage, the system controls the battery to begin discharging. Simultaneously, the charging system also activates the inverter function of the power converter to release the discharged energy into the power grid. And / or, the charging system activates the voltage converter corresponding to the energy storage device within the charging system to store the discharged energy in the energy storage device. After discharging, the battery can switch to charging mode to continue charging, preventing the battery from remaining uncharged for extended periods.

[0115] The above method determines whether the preset power conditions are met based on the charging and discharging parameters of each currently connected battery, specifically including:

[0116] Based on the discharge parameters of the current discharging battery and the discharge request parameters of the battery currently requesting discharge, calculate the total discharge power of all currently connected batteries; based on the charging parameters of the current charging battery, calculate the total charging power of all currently connected batteries; based on the total charging power and total discharging power, determine whether the preset power conditions are met.

[0117] The term "currently discharging battery" refers to a battery currently in the discharging stage. Its discharge parameters include the actual discharge current and voltage output by the charging device connected to the currently discharging battery in response to its discharge request. The term "currently requesting discharge battery" refers to a battery that has sent a discharge request to the charging device but has not yet discharged. Its discharge request parameters include the discharge request current and voltage carried in its discharge request. The term "currently charging battery" includes batteries currently in the charging stage and batteries currently requesting charging, where the battery requesting charging has not yet started charging. The charging parameters of a battery currently in the charging stage include the actual charging current and voltage output by the charging device in response to its charging request. The charging parameters of a battery currently requesting charging include the charging request current and voltage carried in its current charging request.

[0118] Based on the charging and discharging parameters of each currently connected battery, the total charging power and total discharging power of all currently connected batteries can be quantitatively calculated. Based on the calculated total charging power and total discharging power, it can be accurately determined whether the preset power conditions are met, and thus accurately determine the discharge path of the battery currently requesting discharge.

[0119] To calculate the total charging power, we can multiply the actual charging current and actual charging voltage of each battery currently charging to obtain its charging power. We can also calculate the product of the requested charging current and requested charging voltage of the battery currently requesting charging to obtain its requested charging power. Finally, we calculate the sum of the charging power of each battery currently charging and the requested charging power of each battery currently requesting charging to obtain the total charging power of all currently connected batteries.

[0120] For the total discharge power, the discharge power of all currently discharging batteries is calculated based on their discharge parameters. Specifically, the discharge power of the current discharging battery is calculated by multiplying its actual discharge current by its actual discharge voltage. The requested discharge power of the battery currently requesting discharge is calculated based on its discharge request parameters. Specifically, the requested discharge power of the battery currently requesting discharge is calculated by multiplying its requested discharge current by its requested discharge voltage. The total discharge power of all currently discharging batteries is obtained by summing the discharge power of all currently discharging batteries with their requested discharge power.

[0121] By taking into account both the battery currently in the discharge phase and the battery currently requesting discharge, the final calculated total discharge power is more accurate, improving the accuracy of subsequent judgments on whether the current power conditions are met, and thus enabling a more accurate determination of the battery's discharge path.

[0122] To facilitate understanding of the control process provided in the embodiments of this application, the charging and discharging process of the charging system for multiple batteries will be described below starting from the charging initiation stage. In the charging initiation stage, all electrical devices begin charging, so at this time, the total charging power Wc ≥ the total discharging power Wdisc, meaning that the preset power condition is met in the charging initiation stage. Therefore, each electrical device can immediately enter the charging stage after establishing a charging / discharging connection and communication connection with the charging device.

[0123] The control unit of the charging system detects in real time whether it receives a discharge request from the battery of the device. When a discharge request is detected, it determines the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected battery. Since the control process of the charging device is the same for any battery discharge request, this embodiment of the application uses a first battery as an example for explanation. The first battery is any one of the multiple batteries that have established a charging and discharging connection with the charging device.

[0124] Specifically, the charging device receives a discharge request from the first battery, which includes the current voltage of the first battery, the requested discharge current, and the requested discharge voltage. Based on the current charging power of the charging battery, the current discharging power of the discharging battery, and the requested discharge power of the first battery, the charging device determines whether the preset power conditions are met.

[0125] When the charging system receives a discharge request from a battery, it calculates the total charging and discharging power based on the charging and discharging parameters of all batteries. Based on this calculation, it determines whether the requested battery is allowed to discharge and establishes its discharge path. This ensures that the total charging power of the connected batteries is greater than or equal to the total discharging power, allowing the energy released by all discharging batteries to be directly charged into the charging batteries via the DC bus, without needing to undergo multiple conversion stages before being discharged to the grid or the charging system's energy storage device. This results in a very short conversion path for the released energy, improving charging efficiency, eliminating lithium-ion buildup on the negative electrode during discharge, enhancing charging safety, and minimizing energy loss, thus avoiding additional costs for the user.

[0126] Upon receiving a discharge request from the first battery, the total discharge power is calculated by summing the discharge power of all currently discharging batteries with the requested discharge power of the first battery. Similarly, the total charging power is calculated by summing the charging power of all currently charging batteries with the requested charging power of the currently requesting battery. The total charging power is then determined to be greater than or equal to the total discharge power. If so, the discharge path for the first battery is determined to be from the first battery through the DC bus to the battery in the charging phase, and the first battery is controlled to discharge according to the determined discharge path. If not, the first battery is controlled to pause discharging.

[0127] Specifically, after establishing charging and discharging connections with multiple batteries, the charging system continuously monitors the actual current and voltage values ​​output by the charging device connected to each battery. For each currently discharging battery, the charging system detects the actual current and voltage values ​​output by the charging device connected to that battery, calculates the product of these current and voltage values, and obtains the discharge power of that battery. The discharge power of each currently discharging battery can be calculated in the same way. The requested discharge current and requested discharge voltage of the first battery are extracted from its discharge request, and their product is calculated to obtain the requested discharge power of the first battery. The sum of the discharge power of each currently discharging battery and the requested discharge power of the first battery is then calculated to obtain the current total discharge power.

[0128] For each currently charging battery, the charging system also detects the charging device connected to it, detects the actual current and voltage values ​​output by the charging device, and calculates the product of these current and voltage values ​​to obtain the charging power of the current battery. For each battery currently requesting charging, the charging system extracts the requested charging current and requested charging voltage from the charging request, calculates the product of the requested charging current and requested charging voltage to obtain the requested charging power of the current battery. The total charging power is obtained by summing the charging power of each currently charging battery with the requested charging power of each battery. It should be noted that for each charging request from a currently requesting battery, the charging device connected to that battery will respond immediately according to the requested charging current and requested charging voltage carried in the charging request.

[0129] If the preset power condition is met (total charging power greater than or equal to total discharging power), it indicates that if the first battery is allowed to discharge, the released electrical energy can be accepted by the battery in the charging stage. Therefore, the charging system activates the discharge function of the charging device connected to the first battery. Based on the requested discharge current and voltage included in the first battery's discharge request, the system controls the first battery to discharge. At this time, current flows from the first battery, through the DC bus, and directly into the battery in the charging stage. If the preset power condition is not met (total charging power less than total discharging power), it indicates that if the first battery is allowed to discharge, the released electrical energy will not be accepted by the battery in the charging stage. Therefore, the charging system controls the first battery to pause discharging.

[0130] The charging system calculates the total charging power and total discharging power of all batteries by detecting the current and voltage output of each charging device. Through automatic power calculation and the judgment logic of the magnitude of the total charging power and total discharging power, it automatically determines whether the first battery is allowed to discharge, so that the electrical energy released by the battery can be directly charged to the battery in the charging stage through the DC bus, thereby improving charging efficiency and reducing power loss.

[0131] To pause the discharge of a battery requesting discharge, in one implementation, the current voltage of the battery can be obtained from the battery's discharge request. The output voltage of the charging device connected to the battery can then be set to the current voltage of the battery. Once the output voltage of the charging device is the same as the current voltage of the battery, the potential of the charging device and the battery are the same, thus making the output current of the charging device zero. In another implementation, the charging devices all have a built-in pause function. The charging system can control the charging device connected to the battery to activate the pause function, thus pausing the output current.

[0132] When the total charging power is less than the total discharging power, the battery requesting discharge is controlled to pause discharging to avoid redundant power that cannot be accepted by the battery in the charging stage in the entire charging system. The control process is simple and efficient by controlling the charging device connected to the battery to pause output or output current to zero.

[0133] In some embodiments of this application, there may be multiple batteries in a paused discharge state at the same time, and multiple discharge requests may be received from batteries at the same time. For ease of description, the embodiments of this application refer to both batteries in a paused discharge state and batteries currently requesting discharge as batteries awaiting discharge. In application scenarios where there are multiple batteries awaiting discharge in the system, the system periodically determines whether a preset power condition is met, or determines whether to control these batteries awaiting discharge to discharge, either when a battery is detected to be switching from a discharge state to a charging state.

[0134] In determining whether to control the discharge of these batteries, the first step is to identify all possible combinations of batteries to be discharged, with each combination including at least one battery to be discharged. For example, assuming that batteries A, B, and C are currently in a paused discharge state, the possible combinations of these three batteries include battery A, battery B, battery C, (battery A, battery B), (battery A, battery C), (battery B, battery C), and (battery A, battery B, battery C), for a total of 7 possible combinations.

[0135] For each of the above combinations, the discharge power of each current discharge battery is calculated based on its discharge parameters; the requested discharge power of each battery to be discharged in each combination is calculated based on its discharge parameters. The total discharge power for each combination is then calculated based on the discharge power of all current discharge batteries and the requested discharge power of the batteries to be discharged in each combination.

[0136] The charging system detects the actual current and voltage values ​​output by the charging device currently connected to each battery, calculates the product of the current and voltage values ​​for each battery in a discharging state, and obtains the discharge power of each discharging battery. It then calculates the product of the requested discharge current and requested discharge voltage for each battery in the current combination, obtaining the requested discharge power for each battery in the combination. Finally, it calculates the discharge power of each discharging battery and the requested discharge power of each battery in the combination to obtain the current total discharge power for the combination. For each battery in a charging state, it calculates the product of the current and voltage values ​​output by the corresponding charging device to obtain the charging power of that battery. Finally, it calculates the sum of the charging power of each charging battery to obtain the current total charging power.

[0137] When there are multiple batteries to be discharged, the total discharge power corresponding to each combination of these batteries is calculated. This allows us to determine whether each combination meets the preset power conditions, making charge and discharge control more flexible and helping to find the optimal combination for charge and discharge control.

[0138] For each combination, it is determined whether a preset power condition is met, i.e., whether the current total charging power is greater than or equal to the total discharging power corresponding to the combination. If so, the combination is determined to meet the preset power condition and is considered a candidate combination. For each combination in the entire set, the above procedure is followed to determine whether there is a combination in the entire set whose total discharging power is less than or equal to the current total charging power.

[0139] If one or more candidate combinations are determined through the above method, the discharge path of the battery that is allowed to discharge is determined based on the determined combination, and the discharge of the battery that is allowed to discharge is controlled.

[0140] When there are multiple batteries to be discharged, the entire combination of these batteries is determined, and each combination is judged to see if it meets the preset power conditions. Based on the control of the total charging power and the total discharging power, it is possible to determine whether one or more batteries can be allowed to discharge, making the control process more flexible and efficient when there are multiple batteries to be discharged.

[0141] In some embodiments, if it is determined that there is only one combination where the total discharge power is less than or equal to the current total charging power, then the batteries to be discharged in the determined combination are controlled to discharge, and the discharge path is from the batteries to be discharged in the combination through the DC bus to the batteries in the charging stage. In other embodiments, if it is determined that there are multiple combinations where the total discharge power is less than or equal to the current total charging power, then a target combination containing the most batteries is determined from the determined combinations; if a target combination is determined, then each battery to be discharged in the target combination is controlled to discharge. If multiple target combinations are determined, then the target combination with the longest pause time for battery discharge is selected from the multiple target combinations, and each battery to be discharged in the selected target combination is controlled to discharge.

[0142] When multiple candidate combinations are identified, the combination containing the largest number of batteries to be discharged is selected. This allows for control of the discharge of more batteries, shortening the total charging time. If multiple combinations contain the largest number of batteries to be discharged, the duration of the discharge pause for each battery in each of these combinations is determined. The battery with the longest pause is identified, and the discharge of each battery in the combination containing that battery is controlled. This ensures that the battery with the longest pause resumes discharge, preventing it from waiting too long.

[0143] In this embodiment, considering the scenario where multiple batteries establish charging / discharging connections with the charging device simultaneously, it is easy for multiple batteries to be simultaneously in the charging and discharging stages. When multiple batteries are simultaneously in the discharging stage, the total charging power of the entire system is likely to be less than the total discharging power, thus causing multiple batteries to be in a paused discharging state at the same time. Therefore, in this embodiment, if the charging system detects that multiple batteries have established charging / discharging connections simultaneously, the charging system controls the charging device connected to each of these batteries to start its charging function sequentially.

[0144] like Figure 5 As shown, vehicles 1, 2, and n are connected to the charging equipment simultaneously, but the actual charging starts sequentially from vehicle 1 to vehicle n. This allows the discharge phases of vehicles 1, 2, and n to be staggered, avoiding multiple vehicles discharging simultaneously in the same time period.

[0145] In other words, although these multiple batteries establish charging and discharging connections with the charging system at the same time, the charging system controls the charging devices connected to each battery to start in a certain time sequence, so that the actual charging process of these multiple batteries starts sequentially. This makes the discharging stages of these multiple batteries not completely synchronized, reducing the possibility of the total charging power being less than the total discharging power, making the subsequent control process smoother, reducing control complexity, and improving charging efficiency.

[0146] In this embodiment, when the charging system simultaneously establishes charging and discharging connections with multiple batteries, the charging system determines the discharge path of the battery requesting discharge based on the charging and discharging parameters of these multiple batteries. This helps ensure that the electricity released by the battery requesting discharge at the same time can be directly charged into the battery requesting charging through the DC bus, resulting in a very short conversion path for this portion of the electricity, maximizing the efficient use of electrical energy, and achieving the highest energy conversion efficiency. In this embodiment, when performing continuous fast charging at ultra-high rates, a rapid switch to discharge mode is adopted to eliminate lithium-ion accumulation at the battery's negative electrode, eliminating the risk of lithium plating in the cell, reducing or even eliminating battery polarization, effectively delaying battery life degradation, ensuring the battery pack is charged in a healthy state, and improving charging safety. The addition of a discharge step during the charging process greatly increases the charging rate and shortens the overall charging time. Even at low temperatures, the alternating charging and discharging mode avoids the situation in traditional unidirectional charging where the battery pack temperature must be heated first before gradually increasing the charging current. Moreover, because the conversion path of the electricity released by the battery is very short, the power loss is minimal, and it does not impose additional cost burdens on the user. It fully considers commercial needs, reducing charging costs for car owners, lowering charging station operating costs, and promoting energy conservation and environmental protection.

[0147] To facilitate understanding of the charging and discharging control method proposed in the embodiments of this application, the following description is provided in conjunction with specific examples. For instance... Figure 2 As shown, assume that vehicles 1, 2, and n are currently charging or about to start charging. After vehicle 1 is physically connected to the DC / DC1 in the charging system, the DC / DC1 establishes a communication connection with vehicle 1 and completes the configuration of charging parameters to enter the charging process. The control unit of the charging system starts the charging functions of the AC / DC and DC / DC1, and outputs according to the BMS requirements of vehicle 1.

[0148] After time t1, while vehicle 1 is charging, vehicle 2 also establishes a physical connection with the charging system. DC / DC2 establishes a communication connection with vehicle 2 and completes the configuration of charging parameters, entering the charging process. During the charging of vehicles 1 and 2, if a discharge request is received from vehicle 2, the total charging power Wc and total discharge power Wdisc are calculated. If Wc ≥ Wdisc, the control unit directly activates the discharge function of DC / DC2. DC / DC2 outputs according to the requested discharge current and voltage carried in the discharge request from vehicle 3. The discharge path is: vehicle 2's battery → DC / DC2 → DC bus → DC / DCm in the charging stage → vehicle m's battery. Otherwise, DC / DC2 maintains a zero-current output state and periodically calculates Wc and Wdisc until Wc ≥ Wdisc, at which point the discharge function of DC / DC2 is activated again.

[0149] After time t2, when vehicle n is charging vehicle 1 and vehicle 2, it establishes a physical connection with DC / DCn. DC / DCn establishes a communication connection with vehicle n and completes the configuration of charging parameters to enter the charging process. During the charging process of vehicle 1, vehicle 2 and vehicle n, if a discharge request is received from vehicle n, Wc and Wdisc are calculated. If Wc ≥ Wdisc, the control unit directly starts the discharge function of DC / DCn. Otherwise, DC / DCn maintains a zero current output state and periodically calculates Wc and Wdisc until Wc ≥ Wdisc, at which point the discharge function of DC / DCn is started again.

[0150] When a charging system simultaneously establishes charging and discharging connections with multiple batteries, it determines the discharge path of the battery requesting discharge based on the battery's charging and discharging parameters. This ensures that the electricity discharged by the battery requesting discharge at the same time can be directly charged into the battery requesting charging via the DC bus. This results in a very short conversion path for the electricity, which not only eliminates the accumulation of lithium ions on the negative electrode through discharge, reducing or even eliminating battery polarization and improving charging safety, but also helps to increase the battery's charging rate and efficiency, achieving safe and fast charging. Moreover, because the conversion path of the electricity released by the battery is very short, the power loss is minimal, and it does not impose any additional cost burden on the user.

[0151] This application also provides a charge / discharge control device for use in a charging system. The charging system includes at least two charging devices, each connected to a battery. This device is used to execute the charge / discharge control methods provided in the above embodiments, such as... Figure 6 As shown, the device includes:

[0152] The discharge path determination module 201 is used to determine the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected batteries when at least one of at least two batteries requests discharge.

[0153] The discharge path determination module 201 is used to determine the discharge path of the battery requesting discharge based on the charging and discharging parameters of each currently connected battery and preset power conditions; the preset power conditions include that the total charging power of all currently connected batteries is greater than or equal to the total discharging power.

[0154] The discharge path determination module 201 is used to determine whether the preset power conditions are met based on the charging and discharging parameters of each currently connected battery; if yes, the discharge path of the battery requesting discharge is determined to be from the battery requesting discharge to the battery requesting charging via the DC bus; if no, the battery requesting discharge is controlled to pause discharging.

[0155] The discharge path determination module 201 is used to periodically determine whether the current preset power condition is met within a preset time period; or, within a preset time period, to determine whether the current preset power condition is met whenever a battery that has switched from a discharge state to a charging state is detected.

[0156] The discharge path determination module 201 is used to determine the discharge path as flowing from the battery requesting discharge to the energy storage device in the power grid and / or charging system if the battery requesting discharge is suspended for a preset duration and still does not meet the preset power condition.

[0157] The discharge path determination module 201 is used to calculate the total discharge power of all currently connected batteries based on the discharge parameters of the current discharging battery and the discharge request parameters of the battery currently requesting discharge; calculate the total charging power of all currently connected batteries based on the charging parameters of the current charging battery; and determine whether the preset power conditions are met based on the total charging power and the total discharge power.

[0158] The discharge path determination module 201 is used to calculate the discharge power of all currently discharging batteries based on the discharge parameters of the currently discharging battery; calculate the requested discharge power of the currently requested battery based on the discharge request parameters of the currently requested battery; and calculate the sum of the discharge power of all currently discharging batteries and the requested discharge power to obtain the total discharge power of all currently connected batteries.

[0159] The discharge path determination module 201 is used to determine the full combination of multiple batteries to be discharged, wherein each combination includes at least one battery to be discharged; calculate the discharge power of each current battery based on the discharge parameters of each current battery; calculate the requested discharge power of each battery to be discharged in each combination based on the discharge parameters of the batteries to be discharged in each combination; and calculate the total discharge power corresponding to each combination based on the discharge power of all current batteries and the requested discharge power of the batteries to be discharged in each combination.

[0160] The discharge path determination module 201 is used to determine whether there is a combination in each combination whose total discharge power is less than or equal to the total charging power; if so, it is determined that the current preset power condition is met.

[0161] The discharge path determination module 201 is used to control the discharge of batteries in a combination if it is determined that the total discharge power is less than or equal to the current total charging power; or, if it is determined that there are multiple combinations with a total discharge power less than or equal to the total charging power, it determines the target combination containing the most batteries in the multiple combinations; if a target combination is determined, it controls the discharge of each battery in the target combination; if multiple target combinations are determined, it selects the target combination with the longest pause in the discharge of batteries in the multiple target combinations and controls the discharge of each battery in the selected target combination.

[0162] The discharge path determination module 201 is used to control the output voltage of the charging device connected to the battery requesting discharge to be the current voltage of the battery requesting discharge; or, control the charging device connected to the battery requesting discharge to suspend output.

[0163] The discharge path determination module 201 is used to control the charging devices connected to the multiple batteries to start the charging function sequentially if the charging system establishes charging and discharging connections with multiple batteries at the same time.

[0164] The charging and discharging control device provided in the above embodiments of this application and the charging and discharging control method provided in the embodiments of this application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application stored therein.

[0165] Figure 7 A schematic block diagram of an electronic device 700 according to an embodiment of this application is shown. Figure 7 As shown, the electronic device 700 includes a processor 710. Optionally, the electronic device 700 also includes a memory 720, wherein the memory 720 is used to store a computer program, and the processor 710 is used to read the computer program and execute the charge and discharge control methods of the various embodiments of the present application based on the computer program.

[0166] This application also provides a computer-readable storage medium for storing a computer program that, when executed by a processor, implements the methods described in the various embodiments of this application.

[0167] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0168] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0169] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0170] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0171] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0172] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, essentially, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0173] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A charging and discharging control method, characterized in that, The method is applied to a charging system, the charging system comprising at least two charging devices, each of which is connected to a battery, and the method includes: When at least one of the at least two batteries requests discharge, the discharge path of the battery requesting discharge is determined based on the charge and discharge parameters of the currently connected battery. The step of determining the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected battery includes: Based on the charging and discharging parameters of each currently connected battery and preset power conditions, the discharge path of the battery requesting discharge is determined; the preset power conditions include that the total charging power of all currently connected batteries is greater than or equal to the total discharging power; under the preset power conditions, the electrical energy released by the battery requesting discharge can be charged into the battery requesting charging via the DC bus.

2. The method according to claim 1, characterized in that, The step of determining the discharge path of the battery requesting discharge based on the charging and discharging parameters of each currently connected battery and preset power conditions includes: Based on the charging and discharging parameters of each currently connected battery, determine whether the preset power conditions are met. If so, the discharge path of the battery requesting discharge is determined to be from the battery requesting discharge to the battery requesting charging via the DC bus. If not, the battery requesting discharge will pause its discharge.

3. The method according to claim 2, characterized in that, After the battery requesting discharge is paused, the following steps are also included: Periodically determine whether the preset power condition is met within a preset time period; or, Within a preset time period, whenever a battery is detected switching from a discharging state to a charging state, it is determined whether the preset power condition is currently met.

4. The method according to claim 3, characterized in that, The method further includes: If the preset power condition is still not met when the duration of the paused discharge of the requested battery reaches the preset duration, then the discharge path is determined to be from the requested battery to the power grid and / or the energy storage device in the charging system.

5. The method according to any one of claims 2-4, characterized in that, The step of determining whether the preset power condition is met based on the charging and discharging parameters of each currently connected battery includes: Calculate the total discharge power of all currently connected batteries based on the discharge parameters of the current discharging battery and the discharge request parameters of the battery currently requesting discharge. Calculate the total charging power of all currently connected batteries based on the charging parameters of the current charging battery. Based on the total charging power and the total discharging power, determine whether the preset power condition is currently met.

6. The method according to claim 5, characterized in that, The step of calculating the total discharge power of all currently connected batteries based on the discharge parameters of the current discharging battery and the discharge request parameters of the battery currently requesting discharge includes: Calculate the discharge power of all currently discharging batteries based on their discharge parameters. Calculate the requested discharge power of the battery currently requesting discharge based on its discharge request parameters. Calculate the sum of the discharge power of all currently discharged batteries and the requested discharge power to obtain the total discharge power of all currently connected batteries.

7. The method according to claim 5, characterized in that, If there are multiple batteries that are paused from discharging and currently requesting discharge, the total discharge power of all currently connected batteries is calculated based on the discharge parameters of the currently discharging battery and the discharge request parameters of the currently requesting battery, including: Determine a complete combination of multiple said batteries to be discharged, wherein each combination includes at least one battery to be discharged; Calculate the discharge power of each current discharge battery based on its discharge parameters; calculate the requested discharge power of each battery in each combination based on its discharge parameters. Calculate the total discharge power for each combination based on the discharge power of all currently discharging batteries and the requested discharge power of the batteries to be discharged in each combination.

8. The method according to claim 7, characterized in that, Based on the total charging power and the total discharging power, determine whether the preset power condition is currently met, including: Determine whether there exists a combination in each combination whose total discharge power is less than or equal to the total charging power; If it exists, then it is determined that the preset power condition is currently met.

9. The method according to claim 8, characterized in that, The method further includes: If it is determined that there exists a combination where the total discharge power is less than or equal to the current total charging power, then the batteries in the determined combination are controlled to discharge; or, If it is determined that there are multiple combinations where the total discharge power is less than or equal to the total charging power, then the target combination containing the largest number of batteries to be discharged is determined from the multiple combinations; if one target combination is determined, then each battery to be discharged in the target combination is controlled to discharge; if multiple target combinations are determined, then the target combination with the longest pause in battery discharge is selected from the multiple target combinations, and each battery to be discharged in the selected target combination is controlled to discharge.

10. The method according to any one of claims 2-9, characterized in that, The control request to suspend battery discharge includes: The output voltage of the charging device connected to the battery requesting discharge is set to the current voltage of the battery requesting discharge; or, The charging device connected to the battery that is requesting discharge will suspend its output.

11. The method according to any one of claims 1-10, characterized in that, The method further includes: If the charging system establishes charging and discharging connections with multiple batteries at the same time, it controls the charging devices connected to the multiple batteries to start charging functions sequentially.

12. A charging and discharging control device, characterized in that, The device is applied to a charging system, the charging system including at least two charging devices, each of which is connected to a battery, and the device includes: A discharge path determination module is used to determine the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected battery when at least one of the at least two batteries requests discharge. The step of determining the discharge path of the battery requesting discharge based on the charging and discharging parameters of the currently connected battery includes: Based on the charging and discharging parameters of each currently connected battery and preset power conditions, the discharge path of the battery requesting discharge is determined; the preset power conditions include that the total charging power of all currently connected batteries is greater than or equal to the total discharging power; under the preset power conditions, the electrical energy released by the battery requesting discharge can be charged into the battery requesting charging via the DC bus.

13. A charging system, characterized in that, include: Control unit, power converter, DC bus and multiple charging devices; The power converter is connected to the power grid and the DC bus, respectively. The plurality of charging devices are all connected to the DC bus, and each of the charging devices is used to connect to the battery; The control unit is configured to perform the method described in any one of claims 1-11.

14. The charging system according to claim 13, characterized in that, It also includes energy storage devices and their corresponding voltage converters; The energy storage device is connected to the DC bus via the voltage converter.

15. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1-11.

16. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1-11.

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