Patent Description:
With the development of the times, electric vehicles have huge market prospects and can effectively promote energy saving and emission reduction, which is beneficial to the development and progress of society due to their high environmental protection, low noise, low cost of use, and other advantages.

For electric vehicles and related fields, battery technology is an important factor related to their development, especially the safety performance of batteries, which affects the development and application of battery-related products and the acceptance of electric vehicles by the public. Therefore, how to ensure the safety performance of the battery is a technical problem to be solved.

<CIT> discloses a method of providing power to an electronic device in an energy-efficient manner includes transitioning between power states corresponding to charging and discharging a battery. The state of charge of the battery is detected. Upon detecting a high threshold state of charge, an external power source such as an AC-to-DC adapter is disabled, and the battery to provides primary power to the electronic device. Upon a low threshold state of charge, the AC-to-DC adapter is controlled to provide a high current output to charge the battery and provide primary power to the electronic device. The power states, when cycled over time based on the state of the battery, provide for an energy-efficient method of powering the electronic device.

<CIT> discloses a battery system comprising plurality of batteries and a battery management system software controlling the operations of the battery system, function together with a vehicle charging system that charges electric vehicles using one or both of stored power provided by a battery system, and power provided by a utility power grid. The battery system uses the power grid to charge the batteries therein.

<CIT> discloses a lithium battery charging method and a related device. The method comprises: charging a lithium battery to be charged according to a first preset current (<NUM>); acquiring a cathode voltage of the lithium battery (<NUM>); determining whether the cathode voltage satisfies a first preset condition according to the cathode voltage (<NUM>); if the cathode voltage satisfies the first preset condition, discharging the lithium battery according to a second preset current until the cathode voltage satisfies a second preset condition (<NUM>), wherein the second preset current is not greater than the first preset current; and repeating the steps. The method can improve the charging efficiency while ensuring the safety performance of the battery.

In order to more clearly explain the technical solution of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly described below, and it will be apparent that the drawings described below are only some embodiments of the present application, and other drawings may be obtained from the drawings without exerting creative effort by those of ordinary skill in the art.

Implementations of the present application are described in further detail below in conjunction with the accompanying drawings and embodiments. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, i.e., the present application is not limited to the described embodiments.

In the description of this application, it should be noted that, unless otherwise indicated, "a plurality of" means more than two; the terms "up", "down", "left", "right", "inside", "outside" and the like indicate orientations or positional relationships for ease of description and simplification of the description only, and are not intended to indicate or imply that the device or element in question must have a particular orientation, be constructed and operated in a particular orientation and therefore cannot be construed as limiting to the present application. Furthermore, the terms "first", "second", "third", etc. are used for descriptive purposes only and cannot be understood to indicate or imply relative importance.

In the field of new energy, power battery can be used as the main power source of power consumption apparatus (such as vehicle, ship or spacecraft, etc.), while energy storage battery can be used as the charging source of power consumption apparatus, both of which are self-evident. By way of example and not limitation, in some application scenarios the power battery may be a battery in the power consumption apparatus and the energy storage battery may be a battery in a charging device. Hereinafter both the power battery and the energy storage battery may be collectively referred to as a battery for convenience of description.

At present, most of the batteries on the market are rechargeable batteries, and the most common ones are lithium batteries, such as lithium-ion batteries or lithium-ion polymer batteries. In the charging process, generally, the battery is charged by continuous charging, however, continuous charging of the battery will cause lithium plating and heat generation, which will not only degrade the performance of the battery, greatly shorten the cycle life, but also limit the fast charge capacity of the battery, and may cause disastrous consequences such as burning and explosion, resulting in serious safety problems.

In order to ensure the safety performance of the battery, the present application provides a new method for charging battery and charging system.

<FIG> shows an architecture diagram of a charging system applicable to the embodiments of the present application.

As shown in <FIG>, a charging system <NUM> may include a charging and discharging device <NUM> and a battery system <NUM>. Optionally, the battery system <NUM> may be a battery system in an electric vehicle (including a pure electric vehicle and a pluggable hybrid electric vehicle) or a battery system in other application scenarios.

Optionally, at least one battery pack may be provided in the battery system <NUM>, and the entirety of at least one battery pack may be collectively referred to as battery <NUM>. In terms of the type of battery, the battery <NUM> may be any type of battery, including but not limited to: a lithium ion battery, a lithium metal battery, a lithium sulfur battery, a lead acid battery, a nickel cadmium battery, a nickel hydrogen battery, a lithium air battery, and the like. In terms of battery scale, the battery <NUM> in the embodiment of the present application may be a cell/battery cell, a battery module or a battery pack, each of which may be formed by a plurality of batteries in series and parallel. In the embodiments of the present application, the specific type and scale of the battery <NUM> are not specifically limited.

In addition, in order to intelligently manage and maintain the battery <NUM>, prevent over-charging and over-discharging of the battery, and prolong the service life of the battery, the battery system <NUM> is generally provided with a battery management system (BMS) <NUM> for monitoring the state of the battery <NUM>. Optionally, the BMS <NUM> may be integrated with the battery <NUM> in the same device/apparatus, or the BMS <NUM> may be disposed outside the battery <NUM> as an independent device/apparatus.

Specifically, the charging and discharging device <NUM> is a device for supplementing electric energy for the battery <NUM> in the battery system <NUM> and/or controlling the discharge of the battery <NUM>.

Optionally, the charging and discharging device <NUM> in the embodiments of the present application may be an ordinary charging pile, a super charging pile, a charging pile supporting a vehicle to grid (V2G) mode, or a charging and/or discharging device/ apparatus capable of charging and/or discharging a battery, etc. Embodiments of the present application are not limited to specific types and specific application scenarios of the charging and discharging device <NUM>.

Optionally, as shown in <FIG>, the charging and discharging device <NUM> may be connected to the battery <NUM> through a electric wire <NUM> and to the BMS <NUM> through a communication line <NUM> for realizing information interaction between the charging and discharging device <NUM> and the BMS.

By way of example, the communication line <NUM> includes, but is not limited to, a control area network (CAN) communication bus or a daisy chain communication bus.

Optionally, the charging and discharging device <NUM> can communicate with the BMS <NUM> through a wireless network in addition to the communication line <NUM>. Embodiments of the present application are not particularly limited to the type of wired communication or the type of wireless communication between the charging and discharging device and the BMS <NUM>.

<FIG> shows a schematic flow block diagram of a battery charging method <NUM> according to the embodiments of the present application. Optionally, the method <NUM> of the embodiments of the present application may be applied to the charging and discharging device <NUM> and the battery system <NUM> shown above in <FIG>.

As shown in <FIG>, the battery charging method <NUM> may include the following steps.

Step <NUM>: the Battery Management System BMS acquires a first charging current.

Step <NUM>: the BMS sends the first charging current to the charging and discharging device.

Step <NUM>: the charging and discharging device charges the battery based on the first charging current.

Step <NUM>: if a first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and a voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell, the BMS acquires a first discharging current.

Step <NUM>: the BMS sends a first discharging current to the charging and discharging device.

Step <NUM>: the charging and discharging device controls the battery to be discharged based on the first discharging current.

In an embodiment of that present application, a charging method which can be realized between a charging and discharging device and a BMS is provided, in the process of charging the battery, the charging and discharging device can realize charging and discharging the battery based on the first charging current and the first discharging current sent by BMS, thus avoiding the problems of heating, lithium ion accumulation and the like caused by continues charging of the battery. As heating will cause the temperature of the battery to rise, crystals produced by lithium ion accumulation may puncture the battery, causing electrolyte leakage and short circuit of the battery. The temperature rise and short circuit of the battery may cause safety problems of the battery, such as burning or explosion of the battery. Therefore, through the technical solution of the embodiment of the present application, the charging and discharging device realizes the charging and discharging of the battery based on the first charging current and the first discharging current sent by the BMS, which can ensure the safety performance of the battery. In addition, in the process of continues charging, the continuous aggregation of lithium ions will also cause lithium precipitation problems, which will affect the service life and charge capacity of the battery. Therefore, the technical solution of the embodiment of the present application can also ensure the service life and charge capacity of the battery.

Specifically, in steps <NUM> to <NUM>, the BMS may first enter a charging mode to control the charging and discharging device to charge the battery. First, the BMS acquires the first charging current, and after the BMS sends the first charging current to the charging and discharging device, the charging and discharging device charges the battery based on the received first charging current.

Optionally, the BMS may acquire the first charging current from its own functional unit (e.g., the memory unit or the processing unit), or the BMS may also acquire the first charging current from other devices. In some embodiments, the first charging current may be a preset current, the preset current may be a fixed value, or may vary over time in a preset manner. Optionally, in some other embodiments, the first charging current may also be a current determined according to a state parameter of the battery, and the first charging current varies with a change in the state parameter of the battery.

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

Further, when the charging and discharging device charges the battery based on the first charging current, the BMS can acquire the first cumulative charge amount of the battery and judge whether the first cumulative charge amount is greater than or equal to the first cumulative charge amount threshold. If the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold and the voltage of the battery unit does not exceed the full charge voltage of the battery unit, the BMS acquires the first discharging current.

In particular, as is known from the illustration of the battery in <FIG> above, the battery may include one or more battery cells, and the BMS may monitor whether the battery reaches a fully charged state by monitoring the voltages of one or more battery cells in the battery. Optionally, if the battery includes a plurality of battery cells, the voltages of the plurality of battery cells may be different, in which case it is possible to judge whether the battery reaches a full charge state by judging whether the maximum voltage of the battery cells exceeds the full charge voltage of the battery cells. Optionally, in addition to the maximum voltage of the battery cell, other voltages of the battery cell in the battery may be used to judge whether the battery reaches the full charge state.

If the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold, the BMS acquires a first discharging current, that is, for the battery, the charging mode is switched to the discharging mode on the premise that the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell, that is, the battery does not reach the full charge state.

Optionally, the above first cumulative charge amount may be a first cumulative charge capacity or may also be a first cumulative charge power amount. Correspondingly, if the first cumulative charge amount is the first accumulative charge capacity, the first cumulative charge amount threshold is the first accumulative charge capacity threshold, if the first cumulative charge amount is the first accumulative charge power amount, the first cumulative charge amount threshold is the first accumulative charge power amount threshold.

In some embodiments, the above first cumulative charge amount threshold may be a preset threshold, the preset threshold may be a fixed threshold, or may vary over time in a preset manner.

In some other embodiments, the first cumulative charge amount threshold can also be determined according to the state parameter of the battery, that is, when the state parameter of the battery changes, the first cumulative charge amount threshold also changes accordingly. Through the implementation, the first cumulative charge amount threshold can better adapt to the current state parameter of the battery, so as to better control the current charging process, improve the charging efficiency of the battery, and will not cause damage to the battery.

Further, in steps <NUM> to <NUM>, the BMS acquires a first discharging current and sends the first discharging current to the charging and discharging device, which controls the battery to be discharged based on the received first discharging current.

Optionally, the BMS may acquire the first discharging current from its own functional unit (e.g., the memory unit or the processing unit), or the BMS may also acquire the first discharging current from other devices. In some embodiments, the first discharging current may be a preset current, the preset current may be a fixed value, or may vary over time in a preset manner. Optionally, in some other embodiments, the first discharging current may also be a current determined according to a state parameter of the battery, and the first discharging current varies with a change in the state parameter of the battery. In some embodiments, electricity from the battery may be transferred to the energy storage device and/or the power grid during the discharging mode or discharging phase to facilitate the recycling of electrical energy. The energy storage device can be disposed in the charging and discharging device or outside the charging and discharging device, so as to enable the energy storage device to receive the discharging current of the battery. The embodiments of the present application do not limit the specific arrangement of the energy storage device. Optionally, in the discharging mode, the battery power can be consumed in other ways, and the embodiments of the present application do not limit the specific mode of power consumption.

Further, in the process of controlling the battery discharge by the charging and discharging device, the BMS can acquire the first cumulative discharge amount of the battery in the discharging process and judge whether the first cumulative discharge amount is greater than or equal to the first cumulative discharge amount threshold.

Optionally, the first cumulative discharge amount may be a first cumulative discharge capacity or may also be a first cumulative discharge amount. Correspondingly, if the first cumulative discharge amount is the first cumulative discharge capacity, the first cumulative discharge amount threshold is the first cumulative discharge capacity threshold, if the first cumulative discharge amount is the first cumulative discharge power amount, the first cumulative discharge amount threshold is the first cumulative discharge power amount threshold.

In some embodiments, the first cumulative discharge amount threshold may be a preset threshold, which may be a fixed threshold, or may vary over time in a preset manner.

In some other embodiments, the first cumulative discharge amount threshold can also be determined according to the state parameter of the battery, that is, when the state parameter of the battery changes, the first cumulative discharge amount threshold also changes accordingly. Through the implementation, the first cumulative discharge amount threshold can better adapt to the current state parameter of the battery, so as to better control the current discharging process, improve the discharging efficiency of the battery, and will not cause damage to the battery.

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

Through the above process, the charging and discharging device can realize charging and discharging of the battery based on the first charging current and the first discharging current sent by the BMS, thereby avoiding the problems of heating and lithium ion accumulation caused by continuous charging of the battery, and then avoiding the safety problems of the battery caused by heating and lithium ion accumulation, such as burning or explosion of the battery, and ensuring the safety performance of the battery. In addition, the battery is charged to the first cumulative charge amount based on the first charging current and then the power amount of the battery is released to the first cumulative discharge amount based on the first discharging current, so that lithium ions accumulated in the negative electrode of the battery during the charging process can be released, and the lithium precipitation problem generated during continuous charging can be prevented, thereby improving the service life and charging ability of the battery.

For battery charging, after one charge and one discharge, the battery can be recharged for the second time to continue charging the battery.

Optionally, as shown in <FIG> the battery charging method <NUM> in the embodiments of the present application may further include the following steps.

Step <NUM>: if the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS acquires a second charging current.

Step <NUM>: the BMS sends the second charging current to the charging and discharging device.

Step <NUM>: the charging and discharging device charges the battery based on the second charging current.

Specifically, in the above steps <NUM> to <NUM>, when the BMS judges that the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS acquires the second charging current and sends the second charging current to a charging and discharging device, and the charging and discharging device continues to charge the battery based on the received second charging current, i.e., for the battery, the charging mode is re-entered from the discharging mode. Optionally, other related technical solutions of steps <NUM> to <NUM> may be referred to above in relation to the description of steps <NUM> to <NUM> and will not be repeated here.

Understandably, in the above embodiments of the present application, in addition to the current information required for charging and discharging the battery, voltage information required for charging and discharging is also required. For example, in steps <NUM> to <NUM>, the BMS acquires the first charging current and the first charging voltage, and sends the first charging current and the first charging voltage to the charging and discharging device for charging the battery based on the first charging current and the first charging voltage. In steps <NUM> to <NUM>, the BMS acquires the first discharging current and the first discharging voltage and sends the first discharging current and the first discharging voltage to the charging and discharging device for discharging a battery based on the first discharging current and the first discharging voltage. The subsequent charging and discharging process can be similar to the above charging and discharging process and will not be described here.

<FIG> is a schematic flow block diagram of another battery charging method <NUM> of the embodiments of the present application.

As shown in <FIG>, the battery charging method <NUM> may further include the following steps in addition to steps <NUM> to <NUM> described above.

Step <NUM>: if the second cumulative charge amount of the battery is greater than or equal to the second cumulative charge amount threshold and the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell, the BMS acquires the second discharging current.

Step <NUM>: the BMS sends the second discharging current to the charging and discharging device.

Step <NUM>: the charging and discharging device controls the battery to be discharged based on the second discharging current.

In the embodiment of the present application, the charging, discharging, re-charging and re-discharging of the battery are completed through the information interaction between the BMS and the charging and discharging device. In this way, the embodiments of the present application can further provide a charging and discharging method with multiple cycles, wherein the charging and discharging processes are cyclically carried out in turn, and the gradual charging of the battery is realized on the basis of ensuring the safety performance of the battery.

Specifically, in step <NUM>, when the charging and discharging device charges the battery based on the second charging current, the BMS can acquire the second cumulative charge amount of the battery and judge whether the second cumulative charge amount is greater than or equal to the second cumulative charge amount threshold.

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

Similar to the first cumulative charge amount and the first cumulative charge amount threshold described above, in the embodiments of the present application, the second cumulative charge amount may be a second cumulative charge capacity or may also be a second cumulative charge power amount. Correspondingly, if the second cumulative charge amount is the second accumulative charge capacity, the second cumulative charge amount threshold is the second accumulative charge capacity threshold, if the second cumulative charge amount is the second accumulative charge power amount, the second cumulative charge amount threshold is the second accumulative charge power amount threshold.

Optionally, in some embodiments, the above second cumulative charge amount threshold may be a preset threshold, the preset threshold may be a fixed threshold, or may vary over time in a preset manner.

In some other embodiments, the second cumulative charge amount threshold can also be determined according to the state parameter of the battery, that is, when the state parameter of the battery changes, the second cumulative charge amount threshold also changes accordingly.

Further, in step <NUM>, the BMS acquires the second discharging current when the second cumulative charge amount is greater than or equal to the second cumulative charge amount threshold, and the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell. And in steps <NUM> to <NUM>, the BMS sends the second discharging current to the charging and discharging device, and the charging and discharging device controls the battery to be discharged based on the received second discharging current.

Specifically, other related technical solutions in the above steps can be referred to the related descriptions of steps <NUM> to <NUM> above, and will not be repeated here.

As an example, <FIG> shows a schematic waveform diagram of a charging current and a discharging current of a battery provided by an embodiment of the present application.

As shown in <FIG>, in a time period from t1 to t2, the charging and discharging device charges the battery based on the first charging current, the charging continues until the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold, and the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell. In the time period from t2 to t3, the charging and discharging device controls the battery to be discharged based on the first discharging current, the discharging continues until the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, and Optionally, a duration of the first discharging current may be less than a duration of the first charging current. In the time period from t3 to t4, the charging and discharging device continuously charges the battery based on the second charging current, the charging continues until the second cumulative charge amount of the battery is greater than or equal to the second cumulative charge amount threshold and the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell. In the time period from t4 to t5, the charging and discharging device controls the battery to be discharged based on the second discharging current, the discharging continues until the second cumulative discharge amount of the battery is greater than or equal to the second cumulative discharge amount threshold, and optionally, a duration of the second charging current may be less than the duration of the first charging current. It can be understood that the charging and discharging process continues until the battery is fully charged.

It should be noted that, waveform diagrams of the first charging current, the second charging current, the first discharging current and the second discharging current are only schematically shown in <FIG>, the first charging current in the time period from t1 to t2 may be a constant current as shown in <FIG>, or may also be a time varying current, and similarly, the second charging current, the first discharging current and the second discharging current may be constant currents as shown in <FIG>, or may also be time varying currents. In addition, the magnitudes of the first charging current and the second charging current schematically shown in <FIG> are the same, and the magnitudes of the first discharging current and the second discharging current are also the same. In addition, the magnitudes of the first charging current and the second charging current may also be different, and the magnitudes of the first discharging current and the second discharging current may be different as well, which is not specifically limited by the embodiments of the present application.

Step <NUM>: if the voltage of the battery cell of the battery exceeds the full charge voltage of the battery cell, the BMS sends a charge stop command to the charging and discharging device.

Step <NUM>: the charging and discharging device stops charging the battery.

Specifically, as described above, the BMS may monitor whether the battery reaches the fully charge state by monitoring the voltages of one or more battery cells in the battery. Optionally, in some embodiments, it may be determined whether the battery reaches a full charge state by determining whether the maximum voltage of the battery cell exceeds the full charge voltage of the battery cell. When the maximum voltage of the battery cell exceeds the full charge voltage of the battery cell, it indicates that the battery reaches the full charge state, and the BMS sends the charge stop command to the charging and discharging device at this time, and the charge stop command is used to instruct the charging and discharging device to stop charging the battery, so that the charging and discharging device stops charging the battery.

Optionally, steps <NUM> and <NUM> may be performed during the charging phase of the battery. In other words, when the BMS enters the charging mode, and after the charging and discharging device receives the charging current sent by BMS, in the process of charging the battery, the BMS can acquire the voltage of the battery cell to judge whether the battery reaches the full charge state. Once the voltage of the battery cell exceeds the full charge voltage of the battery cell, the BMS sends the charge stop command to the charging and discharging device to make the charging and discharging device stop charging the battery.

Thus, <FIG> only schematically shows that step <NUM> and step <NUM> are executed after step <NUM>, i.e., executed in a process of the second charging, and it will be understood that step <NUM> and step <NUM> may also be executed during any one charging process of multiple charging and discharging processes.

Optionally, in the method embodiments described above, since the charging and discharging device is used for charging, discharging and recharging the battery, the safety problem caused by continuous charging to the battery can be prevented. Further, the charging current in the method can be a large current, so as to improve the charge amount of the battery in the single charging process and realize the purpose of rapid charging.

In addition, limited by the accumulation of lithium ions at the negative electrode during continuous charging, the charging current is also limited, therefore, it is impossible to use continuous large current to realize rapid charging of the battery, according to the technical solution of the embodiment of the present application, the battery is charged by using a large current, and the battery is discharged after a large current charging, so as to release lithium ions accumulated in the negative electrode of the battery during the charging process, and then the battery can be recharged by using a large current to realize rapid charging of the battery.

Specifically, in the above method, the first charging current and/or the second charging current may be large currents, and after the charging and discharging device charges the battery based on the second charging current, the charging current of the subsequent charging process may also be a large current.

Optionally, in order to realize large current fast charging, the charging rate of the first charging current and/or the second charging current ranges from 2C to 10C.

Furthermore, the discharging current in the embodiments of the present application is a small current, aiming at releasing lithium ions gathered in the negative electrode of the battery through the discharge of the battery with the small current, without causing excessive loss of amount of charge which has entered the battery.

Specifically, in the above method, the first discharging current and/or the second discharging current may be small currents, and after the charging and discharging device controls the battery to be discharged based on the second discharging current, the discharging current of the subsequent discharging process may also be a small current.

Optionally, in order to realize discharging at a small current, the charging rate of the first discharging current and/or the second discharging current ranges from <NUM>.

Optionally, in the above method, in order to better control the charge amount of the battery in the charging process and the discharge amount of the battery in the discharging process, a ratio of the cumulative discharge amount threshold in the discharging process and the cumulative charge amount threshold in the charging process can be set so that the discharge amount is relatively small without causing excessive loss of the amount of charge which has entered the battery.

As an example, in the above method, a ratio of the first cumulative discharge amount threshold to the first cumulative charge amount threshold is less than or equal to <NUM>%, and/or a ratio of the second cumulative discharge amount threshold to the second cumulative charge amount threshold is less than or equal to <NUM>%.

In addition, after the charging and discharging device charges the battery and controls the battery to be discharged based on the second charging current and the second discharging current, the ratio of the cumulative discharge amount threshold to the cumulative charge amount threshold in the subsequent charging and discharging process may also be less than or equal to <NUM>%.

It should be noted that the above ratio of <NUM>% can also be adjusted with the change of application scenarios and application requirements, and the specific value of this ratio is not limited in the present application.

Optionally, in the method embodiments described above, the first charging current and the second charging current acquired by the BMS may be the same or different. The first charging current and/or the second charging current may be a preset current. Optionally, the first charging current and/or the second charging current may also be currents determined according to the state parameter of the battery. When the state parameter of the battery changes, the first charging current and/or the second charging current may be different currents corresponding to different state parameters. The state parameter of the battery includes at least one of the following parameters: battery temperature, battery voltage, battery current, battery state of charge (SOC), battery state of health (SOH) and the like.

Similarly, the first and second discharging currents acquired by the BMS may be the same or different. The first discharging current and/or the second discharging current may be a preset current, or the first discharging current and/or the second discharging current may also be a current determined according to the state parameter of the battery.

If at least one of the first charging current, the second charging current, the first discharging current and the second discharging current is a current determined according to the state parameter of the battery, it can better adapt to the current state parameter of the battery, improve the charging efficiency and/or discharging efficiency of the battery, and will not cause damage to the battery.

In addition, after the charging and discharging device charges the battery based on the second charging current and the second discharging current and controls the battery to be discharged, the charging current and/or the discharging current in the subsequent charging and discharging process may also be preset currents, or may be currents determined according to the state parameters of the battery.

Based on the method <NUM> shown above in <FIG>, as shown in <FIG>, step <NUM> above may include:
step <NUM>: the BMS acquiring the state parameter of the battery and determines a first charging current according to the state parameter.

Step <NUM> above may include:
step <NUM>: if a first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and a voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell, the BMS acquiring the state parameter of the battery and determines the first discharging current according to the state parameter.

Step <NUM> above may include:
step <NUM>: if the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS acquiring the state parameter of the battery and determines the second charging current according to the state parameter.

In addition, other steps of method <NUM> in the embodiments of the present application may be referred to above in relation to the description of the embodiments shown in <FIG> and will not be repeated here.

Specifically, in the embodiments of the present application, the first charging current, the first discharging current and the second charging current are all currents determined according to the state parameters of the battery. BMS can obtain different state parameters of the battery in different time periods, and determine the current charging current and discharging current according to the state parameters.

Optionally, determining the charging current and the discharging current according to the state parameters of the battery can be realized in a plurality of ways. As an example, the mapping relationships between the state parameters of the battery and each of the charging current and the discharging current can be acquired, according to the mapping relationships, the specific charging current and discharging current are determined by the state parameters of the battery, wherein the mapping relationships can be obtained by fitting a large number of experimental data, which has high reliability and accuracy, and the mapping relationship can be a mapping table, a mapping diagram or a mapping formula, etc. In addition, in other examples, a special neural network model can be trained according to a large number of experimental data, and the neural network model can output charging current and discharging current according to the input state parameters of the battery.

Optionally, in addition to the charging current and the discharging current, the first cumulative charge amount threshold and the second cumulative charge amount threshold may be the same or different in the above method embodiments. The first cumulative discharge amount threshold and the second cumulative discharge amount threshold may be the same or different. At least one of the first cumulative charge amount threshold, the second cumulative charge amount threshold, the first cumulative discharge amount threshold and the second cumulative discharge amount threshold may be a preset threshold. Optionally, at least one of the first cumulative charge amount threshold, the second cumulative charge amount threshold, the first cumulative discharge amount threshold and the second cumulative discharge amount threshold may be a threshold determined according to the state parameter of the battery.

In addition, after the charging and discharging device charges the battery based on the second charging current and the second discharging current and controls the battery to be discharged, the cumulative discharge amount threshold and the cumulative charge amount threshold in the subsequent charging and discharging process may be preset thresholds or may be thresholds determined according to the state parameters of the battery.

With the embodiments of the present application, if at least one of the first cumulative charge amount threshold, the second cumulative charge amount threshold, the first cumulative discharge amount threshold and the second cumulative discharge amount threshold is a threshold determined according to the state parameter of the battery, it can better adapt to the current state parameters of the battery, so as to better control the current charging process and/or discharging process, ensure the charge amount and discharge amount, and realize the efficient charging of the battery.

Optionally, in the method embodiments described above, at least one of the first charging current, the second charging current, the first discharging current and the second discharging current may be a current periodically or aperiodically acquired by the BMS, As an example, At least one of the first charging current, the second charging current, the first discharging current and the second discharging current may be a current periodically or aperiodically determined by the BMS based on a state parameter of the battery, The current varies with a change in a state parameter of the battery, in particular, the BMS may periodically acquire the state parameter of the battery to determine at least one of a first charging current, a second charging current, a first discharging current, and a second discharging current; Optionally, the BMS acquires a state parameter of the battery in real time, and when the state parameter varies aperiodically, the BMS determines at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current according to the aperiodically changed state parameter.

Further, on this basis, the BMS periodically or aperiodically sends at least one of the first charging current, the second charging current, the first discharging current, and the second discharging current to the charging and discharging device, such that the charging and discharging device charges the battery or controls the battery to be discharged based on the periodically or aperiodically sent current.

In this implementation, in the process of single charging and/or single discharging of the battery by the charging and discharging device, the charging current and/or discharging current are sent periodically or aperiodically by the BMS, on the one hand, the charging current and/or discharging current can be periodically or aperiodically adjusted by the embodiment to improve the charging and discharging efficiency; on the other hand, the charging current and/or discharging current sent periodically or aperiodically can indicate that the state of the BMS and the battery is normal, and the charging and discharging device can continue to charge the battery or control the battery to be discharged. Therefore, in this embodiment, if the charging and discharging device does not receive the charging current and/or discharging current sent periodically or aperiodically by the BMS, the charging and discharging device can stop charging the battery and/or stop controlling the battery to be discharged, so as to ensure the safety performance of the battery.

Based on the method <NUM> shown above in <FIG>, as shown in <FIG>, step <NUM> above may include:.

In the embodiments of the present application, the BMS can periodically acquire the first charging current, the first discharging current, and the second charging current. Correspondingly, the BMS can periodically send the first charging current, the first discharging current and the second charging current to the charging and discharging device.

It can be understood that in the above embodiments, in addition to the current information required for charging and discharging, voltage information required for charging and discharging is also required for charging and discharging the battery, and the method of acquiring the voltage required for charging and discharging is not limited to the embodiments of the present invention.

Optionally, in the embodiments of the method, the communication between the BMS and the charging and discharging device is compatible with the existing communication protocol between the charger and the BMS, so that the communication between the BMS and the charging and discharging device is easy to realize and has a good application prospect.

In particular, on the basis of the above method embodiments, the BMS may also acquire at least one of a first charging voltage, a second charging voltage, a first discharging voltage, and a second discharging voltage, and sending at least one of the first charging voltage, the second charging voltage, the first discharging voltage and the second discharging voltage to the charging and discharging device, wherein the first charging current and the first charging voltage are carried in the first battery charging lab (BCL) message, and/or the first discharging current and the first discharging voltage are carried in the second BCL message, and/or the second charging current and the second charging voltage are carried in the third BCL message, and/or the second discharging current and the second discharging voltage are carried in the fourth BCL message.

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

Step <NUM>: the BMS acquires a first charging current.

Step <NUM>: the BMS sends a first BCL message to the charging and discharging device, the first BCL message carrying a first charging current and a first charging voltage.

Step <NUM>: the charging and discharging device charges the battery based on the first charging current and the first charging voltage.

Step <NUM>: if a first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and a voltage of the battery cell of the battery does not exceed a full charge voltage of the battery cell, the BMS acquires a first discharging current and a first discharging voltage.

Step <NUM>: the BMS sends a second BCL message to the charging and discharging device, the second BCL message carrying the first discharging current and a first discharging voltage.

Step <NUM>: the charging and discharging device controls the battery to be discharged based on the first discharging current and the first discharging voltage.

Step <NUM>: if the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the BMS acquires the second charging current and the second charging voltage.

Step <NUM>: the BMS sends the third BCL message to the charging and discharging device, the third BCL message carrying the second charging current and the second charging voltage.

Step <NUM>: the charging and discharging device charges the battery based on the second charging current and the second charging voltage.

In the embodiments of the present application, the BMS sends a charging current and a discharging current to a charging and discharging device using a BCL message in a communication protocol between the existing charger and the BMS, and the charging and discharging device charges or controls the battery to be discharged based on the received charging current and the discharging current.

Optionally, in the BCL message, the charging voltage (including the first charging voltage and the second charging voltage) and the discharging voltage (including the first discharging voltage and the second discharging voltage) have different ranges, and the charging current (including the first charging current and the second charging current) and the discharging current (including the first discharging current and the second discharging current) have different ranges. In the BCL message received by the charging and discharging device, it can be judged whether it belongs to charging voltage and charging current or discharging voltage and discharging current by the magnitude of the voltage and current carried in it.

Optionally, the BMS may determine the charging voltage and the discharging voltage according to the state parameter of the battery, or the charging voltage and the discharging voltage may be preset values.

Optionally, in some embodiments, the BMS may periodically acquire a charging current and a charging voltage and periodically send a BCL message carrying the charging current and the charging voltage to the charging and discharging device, and similarly, the BMS may periodically acquire a discharging current and a discharging voltage and periodically send a BCL message carrying the discharging current and the discharging voltage to the charging and discharging device. In the implementation, the periodic sending mode of the BCL message can be the same as the periodic sending mode of the BCL message in the prior art standard.

The above example is illustrated by the information interaction message of charging and discharging current and/or voltage, it can be understood that in order to realize the charging and discharging of the battery, besides the processing in the charging and discharging stage, it can also include the handshake interaction between the vehicle and the charger before charging and discharging, the parameter configuration interaction of charging and discharging, etc. The embodiments of the present invention do not specifically limit this.

Optionally, communication protocols between the charger and the BMS include vehicle to grid (V2G) mode and grid to vehicle (G2V) mode.

Specific embodiments of the battery charging method provided by the present application have been described above with reference to <FIG>, and the specific embodiments of the related device provided by the present application will be described below with reference to <FIG>. It can be understood that the related description in the following device embodiments can refer to the foregoing embodiments and will not be repeated here for the sake of brevity.

<FIG> shows a schematic structural block diagram of a battery management system BMS <NUM> according to one embodiment of the present application. As shown in <FIG>, the BMS <NUM> includes an acquisition unit <NUM>, a sending unit <NUM> and a processing unit <NUM>.

In one embodiment of the present application, the acquisition unit <NUM> is used for acquiring a first charging current; the sending unit <NUM> is used for sending the first charging current to the charging and discharging device, so that the charging and discharging device charges the battery based on the first charging current; when the processing unit <NUM> is used for determining that a first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and a voltage of a battery cell of the battery does not exceed the full charge voltage of the battery cell, the acquisition unit <NUM> is also used for acquiring a first discharging current; the sending unit <NUM> is further used for sending the first discharging current to the charging and discharging device, so that the charging and discharging device controls the battery discharge based on the first discharging current. Optionally, when the processing unit <NUM> is further used for determining that when the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, the acquisition unit <NUM> is further used for acquiring a second charging current; and the sending unit <NUM> is further used for sending the second charging current to the charging and discharging device, so that the charging and discharging device charges the battery based on the second charging current.

Optionally, when the processing unit <NUM> is further used for determining that a second cumulative charge amount of the battery is greater than or equal to a second cumulative charge amount threshold and a voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell, the acquisition unit <NUM> is further used for acquiring a second discharging current; and the sending unit <NUM> is further used for sending the second discharging current to the charging and discharging device, so that the charging and discharging device controls the battery to be discharged based on the second discharging current.

Optionally, the processing unit <NUM> is further used for determining that the voltage of the battery cell of the battery exceeds the full charge voltage of the battery cell, and the sending unit <NUM> is further used for sending a charge stop command to the charging and discharging device for instructing the charging and discharging device to stop charging the battery.

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

Optionally, the discharging rate of the first discharging current and/or the second discharging current ranges from <NUM>.

Optionally, a ratio of the first cumulative discharge amount threshold to the first cumulative charge amount threshold is less than or equal to <NUM>%, and/or a ratio of the second cumulative discharge amount threshold to the second cumulative charge amount threshold is less than or equal to <NUM>%.

Optionally, the acquisition unit <NUM> is used for acquiring a state parameter of the battery and determining a first charging current according to the state parameter; and/or the acquisition unit <NUM> is used for acquiring a state parameter of the battery and determining a first discharging current according to the state parameter; and/or the acquisition unit <NUM> is used for acquiring a state parameter of the battery and determining a first discharging current according to the state parameter, wherein the state parameter of the battery includes at least one of a battery temperature, a battery voltage, a battery current, a battery state of charge, and a battery state of health.

Optionally, the acquisition unit <NUM> is used for periodically acquiring the first charging current, and the sending unit <NUM> is used for periodically sending the first charging current to the charging and discharging device; and/or, the acquisition unit <NUM> is used for periodically acquiring the first discharging current, and the sending unit <NUM> is used for periodically sending the first discharging current to the charging and discharging device; and/or, the acquisition unit <NUM> is used for periodically acquiring the second charging current, and the sending unit <NUM> is used for periodically sending the second charging current to the charging and discharging device.

Optionally, the acquisition unit <NUM> is further used for acquiring a first charging voltage, and the sending unit <NUM> is further used for send the first charging voltage to the charging and discharging device, wherein the first charging current and the first charging voltage are carried in the first BCL message; and/or, the acquisition unit <NUM> is further used for acquiring a first discharging voltage, and the sending unit <NUM> is further used for sending the first discharging voltage to the charging and discharging device, wherein the first discharging current and the first discharging voltage are carried in the second BCL message; and/or, the acquisition unit <NUM> is further used for acquiring a second charging voltage, the sending unit <NUM> is further used for sending the second charging voltage to the charging and discharging device, wherein the second charging current and the second charging voltage are carried in the third BCL message, and/or, the acquisition unit <NUM> is also used for acquiring the second discharging voltage, and the sending unit <NUM> is also used for sending the second discharging voltage to the charging and discharging device, wherein the second discharging current and the second discharging voltage are carried in the fourth BCL message.

<FIG> shows a schematic structural block diagram of a charging and discharging device <NUM> according to one embodiment of the present application. As shown in <FIG>, the charging and discharging apparatus <NUM> includes a receiving unit <NUM> and a processing unit <NUM>.

In one embodiment of the present application, the receiving unit <NUM> is used for receiving a first charging current sent by the battery management system BMS; the processing unit <NUM> is used for charging the battery based on the first charging current; the receiving unit <NUM> is further used for receiving a first discharging current sent by the BMS, the processing unit <NUM> is further used for controlling battery discharge based on a first discharging current, wherein the first discharging current is a discharging current sent by the BMS when the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold and the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell; the receiving unit <NUM> is further used for receiving a second charging current sent by the BMS, and the processing unit <NUM> is further used for charging the battery based on the second charging current, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold.

Optionally, the receiving unit <NUM> is further used for receiving a second discharging current sent by the BMS, the processing unit <NUM> is further used for controlling battery to be discharged based on a second discharging current, wherein the second discharging current is a discharging current sent by the BMS when the second cumulative charge amount of the battery is greater than or equal to the second cumulative charge amount threshold and the voltage of the battery cells of the battery does not exceed the full charge voltage of the battery cells.

Optionally, the receiving unit <NUM> is further used for receiving a charge stop command sent by the BMS, and the processing unit <NUM> is used for stopping charging the battery, wherein the charge stop command is a command sent by the BMS when the voltage of the battery cell of the battery exceeds the full charge voltage of the battery cell.

Optionally, at least one of the first charging current, the first discharging current, and the second charging current is determined by the BMS according to the state parameter of the battery, wherein the state parameter of the battery includes at least one of a battery temperature, a battery voltage, a battery current, a battery state of charge, and a battery state of health.

Optionally, the receiving unit <NUM> is used for periodically receiving the first charging current sent by the BMS; and/or, the receiving unit <NUM> is configured to periodically receive the first discharging current sent by the BMS; and/or, the receiving unit <NUM> is used for periodically receiving the second charging current sent by the BMS.

Optionally, the receiving unit <NUM> is further used for receiving a first charging voltage sent by the BMS, wherein the first charging voltage and the first charging current are carried in the first BCL message; and/or, the receiving unit <NUM> is further used for receiving a first discharging voltage sent by the BMS, wherein the first discharging voltage and the first discharging current are carried in the second BCL message; and/or, the receiving unit <NUM> is further used for receiving a second charging voltage sent by the BMS, wherein the second charging voltage and the second charging current are carried in the third BCL message; and/or, the receiving unit <NUM> is further used for receiving a second discharging voltage sent by the BMS, wherein the second discharging voltage and the second discharging current are carried in the fourth BCL message.

Embodiments of a method and device for charging a battery based on information interaction between the charging and discharging device and the BMS provided by the present application are described above in connection with <FIG>, for which charging and controlling the discharge of the battery can be realized through different hardware architectures.

<FIG> shows a schematic structural block diagram of another charging and discharging device provided by the embodiments of the present application.

As shown in <FIG>, the charging and discharging device <NUM> may include a control unit <NUM> and a power conversion unit <NUM>.

In one embodiment, the control unit <NUM> is used for receiving a first charging current sent by the BMS and control the power conversion unit <NUM> to charge the battery based on the first charging current; the control unit <NUM> is further used for receiving a first discharging current sent by the BMS, and controlling the power conversion unit <NUM> to discharge the battery based on a first discharging current, wherein the first discharging current is a discharging current sent by the BMS when the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold and the voltage of the battery cells of the battery does not exceed the full charge voltage of the battery cells. The control unit <NUM> is further used for receiving a second charging current sent by the BMS and controlling the power conversion unit <NUM> to charge the battery based on the second charging current, wherein the second charging current is the charging current sent by the BMS when the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold.

Specifically, the power conversion unit <NUM> may include a high-voltage device for realizing power conversion of a high power, while the control unit <NUM> may include a low-voltage circuit for realizing a control function of the high-voltage device in the power conversion unit <NUM>. In addition, the control unit <NUM> may also establish a communication connection with the BMS, for example, by way of example but not limitation, the control unit <NUM> may establish a communication connection with the BMS through a communication bus, or the control unit <NUM> may also establish a communication connection with the BMS through a wireless network.

Optionally, as an example, <FIG> shows a schematic structural block diagram of the power conversion unit <NUM> provided by the embodiments of the present application.

As shown in <FIG>, the power conversion unit <NUM> may be connected to an alternating current (AC) power source and a battery, where the power conversion unit <NUM> includes a unidirectional alternating current/direct current (AC/DC) converter <NUM> and a first direct current/direct current (DC/DC) converter <NUM>. The first DC/DC converter <NUM> is a unidirectional DC/DC converter.

As can be seen from <FIG>, a first end of the unidirectional AC/DC converter <NUM> may be connected to an AC power source, a second end of the unidirectional AC/DC converter <NUM> may be connected to a first end of the first DC/DC converter <NUM>, and a second end of the first DC/DC converter <NUM> may be connected to a battery to achieve current transfer between the battery and the AC power source.

In this case, the BMS may send a first charging current to the control unit <NUM>, and accordingly, the control unit <NUM> may be used for receiving the first charging current sent by the BMS and control the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> based on the first charging current to charge the battery through by the AC power source.

Also, when the first cumulative charge amount of the battery is greater than or equal to the first cumulative charge amount threshold and the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell, the BMS may send a first discharging current to the control unit <NUM>, which may be used for receiving the first discharging current and controlling the battery to release power based on the first discharging current.

In the process of charging the battery, the charging and discharging device can realize charging and discharging the battery based on the first charging current and the first discharging current sent by the BMS, thereby avoiding continuous charging of the battery, thereby avoiding problems such as heating and lithium ion accumulation caused by continuous charging of the battery. As heating will cause the temperature of the battery to rise, crystals produced by lithium ion accumulation may puncture the battery, causing electrolyte leakage and short circuit of the battery. The temperature rise and short circuit of the battery may cause safety problems of the battery, such as burning or explosion of the battery. Therefore, the charging and discharging device realizes the charging and discharging of the battery based on the first charging current and the first discharging current sent by the BMS, which can ensure the safety performance of the battery. In addition, in the process of continuous charging, the continuous aggregation of lithium ions will also cause lithium precipitation problems, which will affect the service life and charge capacity of the battery. Therefore, charging and discharging device can also ensure the service life and charge capacity of the battery.

Further, the charging and discharging device includes a unidirectional AC/DC converter and a unidirectional DC/DC converter, namely, the structure of the charging and discharging device of the embodiments of the application is the same as that of the existing charging pile, that is to say, the charging and discharging of the battery can be realized without changing the prior charging pile structure, and the charging cost is greatly reduced.

When the first cumulative discharge amount of the battery is greater than or equal to the first cumulative discharge amount threshold, optionally, the control unit <NUM> may also be used for receiving the second charging current sent by the BMS and control the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to charge the battery through the AC power source based on the second charging current.

When the control unit <NUM> controls the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to charge a battery through the AC power source, the control unit <NUM> may sequentially control the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM>.

In addition to the first charging current, the first discharging current and the second charging current, when the second cumulative charge amount of the battery is greater than or equal to the second cumulative charge amount threshold and the voltage of the battery cell of the battery does not exceed the full charge voltage, the BMS may also send a second discharging current to the control unit <NUM>, and accordingly, the control unit <NUM> may also be used for receiving the second discharging current sent by the BMS and controlling the battery release power based on the second discharging current.

When the voltage of the battery cell of the battery exceeds the full charge voltage during the cycle of charging and discharging the battery, the BMS may send a charge stop command to the control unit <NUM>, which is used for instructing the charging and discharging device to stop charging the battery. Accordingly, the control unit <NUM> is used for receiving a charge stop command sent by the BMS, and based on the charge stop command, controlling the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> so that the AC power source stops charging the battery.

In the technical solution, when the voltage of the battery cell exceeds the full charge voltage, the control unit controls the AC/DC converter and the first DC/DC converter by receiving the charge stop command to make the AC power source stop charging the battery, thus preventing the battery from overcharging and further ensuring the safety performance of the battery.

Optionally, as shown in <FIG>, the power conversion unit <NUM> may also include a second DC/DC converter <NUM>. Specifically, the second end of the second DC/DC converter <NUM> may be connected to the battery and the second end of the first DC/DC converter <NUM>, respectively.

Based on this, the control unit <NUM> may specifically be used for controlling the second DC/DC converter <NUM> to release the power of the battery into the energy storage unit based on the first discharging current. In the above technical solution, the power of the battery is released into the energy storage unit, so that the energy storage unit can perform other operations based on the received power, thus avoiding the waste of power.

Optionally, the energy storage unit may be a low-power energy storage unit. For example, the energy storage unit may be a super battery or a lithium carbonate battery. By setting the energy storage unit as a low-power energy storage unit, the cost of the charging system can be reduced.

Optionally, the energy storage unit may be provided independently of the charging and discharging device <NUM>, or the charging and discharging device <NUM> may also include the energy storage unit. When the charging and discharging device includes an energy storage unit, as shown in <FIG>, the energy storage unit may be a part of the power conversion unit <NUM>, or may be a unit independent of the power conversion unit <NUM> and connected to the power conversion unit <NUM> through a wire, which is not specifically limited in the embodiments of the present application.

For convenience of description, a solution of the embodiments of the present application is described below taking the energy storage unit <NUM> as a part of the power conversion unit <NUM> as an example.

As can be seen from <FIG>, in the power conversion unit <NUM>, a first end of the unidirectional AC/DC converter <NUM> is connected to an AC power source, a second end is connected to a first end of the first DC/DC converter <NUM>, the second end of the first DC/DC converter <NUM> is respectively connected to a battery and a second end of the second DC/DC converter <NUM>, and the first end of the second DC/DC converter <NUM> is connected to an energy storage unit <NUM>.

Further, before discharging the battery, the control unit <NUM> may control the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to turn off the mode of charging the battery, and control the second DC/DC converter <NUM> to turn on the mode of discharging the energy storage unit <NUM>.

In one implementation, the second DC/DC converter <NUM> may be a unidirectional DC/DC converter.

In another implementation, given that the battery releases the power into the energy storage unit, since the power that can be stored by the energy storage power source is limited, the power of the energy storage unit may reach full capacity, resulting in the battery being unable to release the power. Thus, referring again to <FIG>, the second DC/DC converter <NUM> may be a bidirectional DC/DC converter.

In this case, in addition to controlling the second DC/DC converter <NUM> to discharge the power of the battery into the energy storage unit <NUM>, the control unit <NUM> may control the second DC/DC converter <NUM> to charge the battery through the energy storage unit <NUM> while controlling the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to charge the battery through the AC power source based on the first charging current. Or, the control unit <NUM> may also control the second DC/DC converter <NUM> to charge the battery through the energy storage unit <NUM> while controlling the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to charge the battery through the AC power source based on the second charging current.

According to the above technical solution, the energy storage unit can not only receive the power released by the battery, but can also charge the battery. On the one hand, it avoids the problem of not being able to continue releasing the power from the battery to the energy storage unit because the power in the energy storage unit has reached the full amount, and ensures that the charging process is carried out normally. On the other hand, the energy storage unit charges the battery by using the received power released by the battery, which realizes the recycling of the battery power and saves electric energy. On yet another hand, the AC power source and the energy storage unit charge the battery at the same time, which is beneficial to improve the charging rate of the battery and save the charging time.

Optionally, the first charging current and the current at which the energy storage unit <NUM> charges the battery may be different, and similarly, the second charging current may be different from the current at which the energy storage unit <NUM> charges the battery. Illustratively, the first charging current may be greater than the current at which the energy storage unit <NUM> charges the battery. For example, the charging rate at which the energy storage unit <NUM> charges the battery may be less than <NUM> C1, C1 is the capacity of the energy storage unit <NUM>.

When charging a battery based on the power conversion unit <NUM> of <FIG>, as a possible embodiment, under any conditions, the control unit <NUM> may control the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to charge the battery through an AC power source, and control the second DC/DC converter <NUM> to charge the battery through the energy storage unit <NUM>.

In another possible embodiment, the control unit <NUM> may first acquire the SOC of the energy storage unit <NUM>, and then determine the AC power source to charge the battery based on the SOC of the energy storage unit <NUM>, or determine that the AC power source and the energy storage unit <NUM> charge the battery simultaneously based on the SOC of the energy storage unit <NUM>.

Optionally, the energy storage unit <NUM> may send a first message including the SOC of the energy storage unit <NUM> to the control unit <NUM>, so that the control unit <NUM> may acquire the SOC of the energy storage unit <NUM>.

Optionally, the energy storage unit <NUM> may store the SOC to the cloud such that the control unit <NUM> may acquire the SOC of the energy storage unit <NUM> from the cloud.

Specifically, if the SOC of the energy storage unit <NUM> is greater than or equal to the state of charge threshold, the control unit <NUM> may control not only the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to charge the battery through the AC power source, but also the second DC/DC converter <NUM> to charge the battery through the energy storage unit <NUM>.

If the SOC of the energy storage unit <NUM> is less than the state of charge threshold, the control unit <NUM> may control only the unidirectional AC/DC converter <NUM> and the first DC/DC converter <NUM> to charge the battery through the AC power source. Optionally, when the SOC of the energy storage unit <NUM> is less than the state of charge threshold, the control unit <NUM> may send a charging request message to other devices to cause other devices to charge the energy storage unit <NUM> until the SOC of the energy storage unit <NUM> is greater than or equal to the state of charge threshold. After that, the AC power source and the energy storage unit <NUM> can charge the battery at the same time.

The state of charge threshold can be a fixed value. Optionally, the state of charge threshold can be a variable. For example, the state of charge threshold can vary with time, environment (such as temperature) and other factors.

The state of charge threshold may be preset on the control unit <NUM> or may be sent to the control unit <NUM> by the energy storage unit.

According to the above technical solution, whether the energy storage unit is used to assist the AC power source to charge the battery together is determined according to the SOC of the energy storage unit, so that the charging efficiency of the charging and discharging device can be improved when the power stored by the energy storage unit is sufficient.

In the process of simultaneously charging the battery by the AC power source and the energy storage unit <NUM>, the first charging power for charging the battery by the energy storage unit <NUM> is W1, and the second charging power for charging the battery by the AC power source is W2, W3 is a difference between the charging demand power of the battery and W1. Optionally, the first charging power W1 may be determined prior to the second charging power W2.

W1 may be determined according to the discharge capability of the energy storage unit <NUM>. In addition, W1 may also be determined according to the state of the energy storage unit <NUM> at the current time, for example, the ampere-hour of the energy storage unit <NUM>, the temperature of the energy storage unit <NUM>, and the like.

Optionally, the AC power source includes, but is not limited to, a power grid that can be used to provide three-phase AC power, and the power grid can not only provide enough power to charge the battery, but also receive more power released by the battery.

Optionally, in other implementations, the AC power source may also be a single-phase AC power source. Embodiments of the present application are not limited to specific types of AC power sources.

In addition, the related technical solutions of charging current, discharging current, cumulative charge amount, cumulative discharge amount, cumulative charge amount threshold, cumulative discharge amount threshold and the like in the embodiments of the present application can be referred to the relevant description above, and will not be repeated here.

<FIG> illustrates a schematic flow diagram of a method <NUM> for charging battery of embodiments of the present application. The method <NUM> may be applied to a charging and discharging device including a first direct current/direct current DC/DC converter and a unidirectional alternating current/direct current AC/DC converter, for example, may be applied to a charging and discharging device including a unidirectional AC/DC converter <NUM> and a first DC/DC converter <NUM> in <FIG>. It should be understood that method embodiments and device embodiments correspond to each other, and the similar descriptions may refer to the device embodiments.

As shown in <FIG>, the method <NUM> for charging battery <NUM> may include the following steps:.

Optionally, in some embodiments, the method <NUM> further includes receiving a second discharging current sent by the BMS, and controlling the battery to release power based on the second discharging current, where the second discharging current is a discharging current sent by the BMS when a second cumulative charge amount of the battery is greater than or equal to a second cumulative charge amount threshold and the voltage of the battery cell of the battery does not exceed the full charge voltage of the battery cell.

Optionally, in some embodiments, the method <NUM> further includes receiving a charge stop command sent by the BMS; and controlling, based on the charge stop command, the unidirectional AC/DC converter and the first DC/DC converter to cause the AC power source to stop charging the battery, where the charge stop command is a command sent by the BMS when the voltage of the battery cell of the battery exceeds the full charge voltage.

Optionally, in some embodiments, the charging and discharging device further includes a second DC/DC converter such as the second DC/DC converter <NUM> in <FIG> and <FIG>. Controlling the battery to release power based on the first discharging current includes controlling the second DC/DC converter to release the power of the battery into an energy storage unit based on the first discharging current.

Optionally, in some embodiments, the second DC/DC converter is a bidirectional DC/DC converter, and the method <NUM> further includes controlling the second DC/DC converter to charge the battery through the energy storage unit while controlling the unidirectional AC/DC converter and the first DC/DC converter to charge the battery through the AC power source based on the first charging current; and/or controlling the second DC/DC converter to charge the battery through the energy storage unit when controlling the unidirectional AC/DC converter and the first DC/DC converter to charge the battery through the AC power source based on the second charging current.

Optionally, in some possible embodiments, a first charging power of the energy storage unit to charge the battery is determined according to a discharge capability of the energy storage unit, and a second charging power of the AC power source to charge the battery is a difference between a charging demand power of the battery and the first charging power.

Optionally, in some embodiments, charging the battery includes: acquiring a battery state of charge SOC value of the energy storage unit; under a condition that the SOC is greater than a SOC threshold, controlling the second DC/DC converter to charge the battery through the energy storage unit, and controlling the unidirectional AC/DC converter and the first DC/DC converter to charge the battery through the AC power source based on the first charging current; and/or under a condition that the SOC is greater than a SOC threshold, controlling the second DC/DC converter to charge the battery through the energy storage unit and controlling the unidirectional AC/DC converter, the first DC/DC converter to charge the battery through the AC power source based on the second charging current.

Optionally, in some embodiments, the charging rate of the first charging current and/or the second charging current ranges from 2C to 10C.

Optionally, in some embodiments, the discharging rate of the first discharging current ranges from <NUM> C to <NUM> C.

Optionally, in some embodiments, the ratio of the first cumulative discharge amount threshold to the first cumulative charge amount threshold is less than or equal to <NUM>%.

Optionally, in some embodiments, at least one of the first charging current, the first discharging current, and the second charging current is determined according to a state parameter of the battery; where the state parameter of the battery includes at least one of a battery temperature, a battery voltage, a battery current, a battery state of charge, and a battery state of health.

Optionally, in some embodiments, receiving a first charging current sent by the BMS of the battery includes periodically receiving the first charging current sent by the BMS; and/or, receiving the first discharging current sent by the BMS includes: periodically receiving the first discharging current sent by the BMS; and/or, receiving the second charging current sent by the BMS includes periodically receiving the second charging current sent by the BMS.

Optionally, in some embodiments, the method <NUM> further includes receiving a first charging voltage sent by the BMS, where the first charging voltage and the first charging current are carried in the first BCL message; and/or receiving a first discharging voltage sent by the BMS, where the first discharging voltage and the first discharging current are carried in the second BCL message; and/or, receiving a second charging voltage sent by the BMS, where the second charging voltage and the second charging current are carried in the third BCL message.

<FIG> shows a schematic structural block diagram of an electronic device <NUM> of one embodiment of the present application. As shown in <FIG>, the electronic device <NUM> includes a memory <NUM> and a processor <NUM>. The memory <NUM> is used for storing a computer program, and the processor <NUM> is used for reading the computer program and executing the methods of various embodiments of the present application described above based on the computer program.

Optionally, the electronic device <NUM> may be used for any one or more of a BMS and a charge-discharge device. In the embodiments of the present application, in addition to the processor in the charging and discharging device reading the corresponding computer program and executing the charging method corresponding to the charging and discharging device in the aforementioned various embodiments based on the computer program, the processor in the BMS can also read the corresponding computer program and execute the charging method corresponding to the BMS in the aforementioned various embodiments based on the computer program.

In addition, the embodiment of the present application also provides a readable storage medium for storing a computer program, and the computer program is used for executing the aforementioned methods of various embodiments of the present application. Optionally, the computer program may be a computer program in the charging and discharging device and/or BMS.

It should be understood that the specific examples herein are only intended to assist those skilled in the art to better understand the embodiments of the present application and are not intended to limit the scope of the embodiments of the present application.

It should also be understood that in various embodiments of the present application, the serial number of each process does not mean the sequence of execution, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Claim 1:
A charging and discharging device, the charging and discharging device being a charging pile, the charging and discharging device comprising a first direct current/direct current, DC/DC, converter (<NUM>), a unidirectional alternating current/direct current, AC/DC, converter (<NUM>) and a control unit, the first DC/DC converter (<NUM>) being a unidirectional DC/DC converter, and the control unit being configured to:
receive a first charging current sent by a battery management system, BMS, of a battery, and control the unidirectional AC/DC converter (<NUM>) and the first DC/DC converter (<NUM>) to charge the battery through an alternative current, AC, power source based on the first charging current, the battery being a power battery;
receive a first discharging current sent by the BMS, and control the battery to release power based on the first discharging current, wherein the first discharging current is a discharging current sent by the BMS when a first cumulative charge amount of the battery is greater than or equal to a first cumulative charge amount threshold and a voltage of a battery cell of the battery does not exceed a full charge voltage of the battery cell; and
receive a second charging current sent by the BMS, and control the unidirectional AC/DC converter (<NUM>) and the first DC/DC converter (<NUM>) to charge the battery through the AC power source based on the second charging current, wherein the second charging current is a charging current sent by the BMS when a first cumulative discharge amount of the battery is greater than or equal to a first cumulative discharge amount threshold;
wherein a first end of the unidirectional AC/DC converter (<NUM>) is connected to an AC power source, a second end of the unidirectional AC/DC converter (<NUM>) is connected to a first end of the first DC/DC converter (<NUM>), and a second end of the first DC/DC converter (<NUM>) is connected to the battery;
wherein the charging and discharging device further comprises a second DC/DC converter (<NUM>); and
the control unit is specifically configured to:
control, based on the first discharging current, the second DC/DC converter (<NUM>) to release the power of the battery into an energy storage unit;
wherein a second end of the second DC/DC converter (<NUM>) is connected to the battery and the second end of the first DC/DC converter (<NUM>), and a first end of the second DC/DC converter (<NUM>) is connected to an energy storage unit.