CN117277476A

CN117277476A - Charging and discharging control method based on parallel battery module and related equipment

Info

Publication number: CN117277476A
Application number: CN202311129806.6A
Authority: CN
Inventors: 陈正标; 覃统成; 叶慧君; 唐志伟; 沈洪智
Original assignee: Shenzhen Xinwangda Energy Technology Co ltd
Current assignee: Shenzhen Xinwangda Energy Technology Co ltd
Priority date: 2023-08-31
Filing date: 2023-08-31
Publication date: 2023-12-22

Abstract

The invention discloses a charge and discharge control method based on a parallel operation battery module and related equipment, wherein the method is applied to the battery module of a parallel operation system and comprises the following steps: acquiring current battery parameters and total power of the parallel operation system; the current battery parameters are sent to a battery module in the parallel operation system, and the battery parameters sent by the battery module of the parallel operation system are received to obtain reference battery parameters; performing power calculation on the total power, the current battery parameters and the reference battery parameters through a preset power distribution model to obtain target power; charging and discharging are carried out according to the target power, and the residual electric quantity in the charging process is collected periodically according to a preset time period, so that updated residual electric quantity is obtained; and adjusting the current in the charging and discharging process according to the preset electric quantity range and the updated residual electric quantity. The invention can lead the battery module of the parallel operation system to charge and discharge uniformly, and reduce the problem of charge/discharge of the parallel operation system.

Description

Charging and discharging control method based on parallel battery module and related equipment

Technical Field

The invention relates to the field of energy storage, in particular to a charging and discharging control method based on a parallel battery module and related equipment.

Background

With the development of new energy technology, electric energy also becomes the main driving energy of the current driving equipment, so the performance requirement of the battery module is also higher and higher. In order to improve the energy storage capacity, a plurality of battery modules are connected to the BUS section of the energy storage converter in a parallel manner to construct a parallel operation system. In the related art, the parallel operation system adopts an average power control strategy to realize charging and discharging of a plurality of battery modules, and when the electric quantity of the battery modules is inconsistent, the problem that the rated power charging/discharging cannot be satisfied may occur. For example, when the electric quantity of one battery module is too low during discharging, the undervoltage protection is triggered to exit the parallel operation system, so that the discharging power is reduced. When the battery is charged, the electric quantity of one battery module is earlier than that of other battery modules, the battery module needs to respond to discharge rapidly and can not be shut down, and the continuous charging triggers the overvoltage protection of the battery cell. Therefore, there is a need to improve the balance of the electric quantity during the charging and discharging of the battery in the parallel operation system, and reduce the charging/discharging problems of the parallel operation system.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a charge and discharge control method based on a parallel operation battery module, which can lead the battery module of the parallel operation system to charge and discharge uniformly and reduce the charge/discharge problem of the parallel operation system.

The invention also provides a battery module.

The invention also provides a parallel operation system.

The invention also proposes a computer readable storage medium.

In a first aspect, an embodiment of the present invention provides a method for controlling charge and discharge based on a parallel operation battery module, applied to a battery module of a parallel operation system, the method including:

acquiring current battery parameters and total power of the parallel operation system;

the current battery parameters are sent to a battery module in the parallel operation system, and the battery parameters sent by the battery module of the parallel operation system are received to obtain reference battery parameters;

performing power calculation on the total power, the current battery parameters and the reference battery parameters through a preset power distribution model to obtain target power;

charging and discharging are carried out according to the target power, and the residual electric quantity in the charging process is collected periodically according to a preset time period, so that updated residual electric quantity is obtained;

And adjusting the current in the charging and discharging process according to the preset electric quantity range and the updated residual electric quantity.

According to other embodiments of the present invention, the current battery parameters include: current remaining power and current battery state of health data, the reference battery parameters include: reference remaining power and reference battery state of health data; the power calculation is performed on the total power, the current battery parameter and the reference battery parameter through a preset power distribution model to obtain a target power, including:

summarizing the reference residual electric quantity and the current residual electric quantity through the power distribution model to obtain total residual electric quantity;

calculating the ratio of the current residual electric quantity to the total residual electric quantity through the power distribution model to obtain a residual electric quantity ratio;

summarizing the reference battery health state data and the current battery health state data through the power distribution model to obtain total battery health state data;

calculating the ratio of the current battery state of health data to the total battery state of health data through the power distribution model to obtain a state of health ratio;

And carrying out power distribution on the residual electric quantity ratio, the health state ratio and the total power through the power distribution model to obtain the target power.

According to other embodiments of the present invention, a method for controlling charge and discharge based on a parallel battery module, wherein the adjusting the current in the charge and discharge process according to the preset power range and the updated remaining power includes:

if the updated residual electric quantity is larger than the upper limit value of the preset electric quantity range, adjusting the current to the lower limit value of the preset current range;

if the updated residual electric quantity is within the preset electric quantity range, controlling the current to be within the preset current range;

and if the updated residual electric quantity is smaller than the lower limit value of the preset electric quantity range, adjusting the current at the upper limit value of the preset current range.

According to other embodiments of the present invention, the preset electric quantity range includes: a first electrical quantity range, a second electrical quantity range, and a third electrical quantity range; the first electric quantity range is smaller than the second electric quantity range, and the second electric quantity range is larger than the third electric quantity range; the preset current range includes: a first current value, a second current value, and a third current value, the first current value being greater than the second current value, the second current value being greater than the third current value; and if the updated remaining capacity is within the preset capacity range, controlling the current within the preset current range, including:

If the updated remaining capacity is in the first capacity range, limiting the current to the first current value;

if the updated remaining capacity is in the second capacity range, limiting the current to the second current value;

and if the updated residual electric quantity is in the second electric quantity range, limiting the current to the third current value.

According to further embodiments of the present invention, the current battery parameter further includes a current voltage value, the reference battery parameter further includes a reference voltage value, and after the current during the charging and discharging is adjusted according to the preset power range and the updated remaining power, the method further includes:

performing difference calculation on the current voltage value and the reference voltage value to obtain a voltage difference value;

if the voltage difference value is larger than a preset voltage difference range, exiting the parallel operation system;

and if the voltage difference value is in the voltage difference range, entering the parallel operation system.

In a second aspect, an embodiment of the present invention provides a battery module disposed in a parallel operation system, the battery module including:

the acquisition module is used for acquiring the current battery parameters and the total power;

The transmission module is used for transmitting the current battery parameters to a battery module in the parallel operation system and receiving the battery parameters transmitted by the battery module of the parallel operation system to obtain reference battery parameters;

the power calculation module is used for carrying out power calculation on the total power, the current battery parameters and the reference battery parameters through a preset power distribution model to obtain target power;

the charging and discharging control module is used for executing charging and discharging according to the target power, and periodically collecting the residual electric quantity in the charging process according to a preset time period to obtain updated residual electric quantity;

and the current adjusting module is used for adjusting the current in the charging and discharging process according to the preset electric quantity range and the updated residual electric quantity.

According to other embodiments of the present invention, a battery module includes:

a battery pack;

the DC-DC unit end is connected with the battery pack;

a BMS module electrically connecting the DC-DC unit and the battery pack; wherein the DC-DC unit includes: the transformer comprises a low-voltage side unit, a high-voltage side unit, a resonance unit and a transformer, wherein the low-voltage side unit is electrically connected with one end of the transformer, the other end of the transformer is connected with one end of the resonance unit, and the other end of the resonance unit is connected with the high-voltage side unit.

In a third aspect, an embodiment of the present invention provides a parallel operation system, including:

a battery module for performing the parallel battery module-based charge and discharge control method according to the first aspect;

the energy storage converter is provided with a connecting end and is connected with the battery module through the connecting end;

and the switching box is electrically connected between the battery module and the energy storage converter and is used for collecting and forwarding battery parameters of each battery module.

In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the parallel battery module-based charge and discharge control method according to the first aspect.

According to the parallel battery module-based charge and discharge control method and the related equipment, the current battery parameters and the total power are obtained, the battery parameters of other battery modules in the parallel battery system are obtained to obtain the reference battery parameters, so that the current battery parameters and the reference battery parameters are subjected to power distribution through the power distribution model to determine the target power of the battery modules in the charging process, the distributed target power is determined according to the battery parameters of each battery module, and balanced battery power distribution is realized. When the power distribution is carried out according to the target power, the residual electric quantity is collected regularly to be used as the updated residual electric quantity, so that the current in the charging process of the battery module is adjusted according to the preset electric quantity range and the updated residual electric quantity, and the sectional current limiting strategy is adopted, so that the current of the battery module in each time period is effectively controlled, each battery module in the parallel operation system is beneficial to being filled at a similar moment, and the problem of overcharging of the battery is effectively solved.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

FIG. 1 is a system architecture diagram of an embodiment of a method for controlling charge and discharge based on a parallel battery module according to an embodiment of the present invention;

FIG. 2 is a flow chart of a method for controlling charge and discharge based on a parallel battery module according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating the step S203 in FIG. 2;

FIG. 4 is a flowchart illustrating the step S305 of FIG. 3;

FIG. 5 is a flowchart illustrating the step S205 in FIG. 2;

FIG. 6 is a flowchart of step S503 in FIG. 5;

FIG. 7 is a flowchart of another embodiment of a method for controlling charge and discharge based on a parallel battery module according to an embodiment of the present invention;

fig. 8 is a block diagram illustrating an exemplary embodiment of a battery module according to an embodiment of the present invention;

fig. 9 is a block diagram illustrating another embodiment of a battery module according to an embodiment of the present invention;

Fig. 10 is a schematic circuit diagram of an embodiment of a DC-DC unit in accordance with an embodiment of the present invention.

Detailed Description

The conception and the technical effects produced by the present invention will be clearly and completely described in conjunction with the embodiments below to fully understand the objects, features and effects of the present invention. It is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and that other embodiments obtained by those skilled in the art without inventive effort are within the scope of the present invention based on the embodiments of the present invention.

In the description of the present invention, if an orientation description such as "upper", "lower", "front", "rear", "left", "right", etc. is referred to, it is merely for convenience of description and simplification of the description, and does not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the invention. If a feature is referred to as being "disposed," "secured," "connected," or "mounted" on another feature, it can be directly disposed, secured, or connected to the other feature or be indirectly disposed, secured, connected, or mounted on the other feature.

In the description of the embodiments of the present invention, if "several" is referred to, it means more than one, if "multiple" is referred to, it is understood that the number is not included if "greater than", "less than", "exceeding", and it is understood that the number is included if "above", "below", "within" is referred to. If reference is made to "first", "second" it is to be understood as being used for distinguishing technical features and not as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

Noun interpretation:

and (3) a battery module: the lithium ion battery cells are combined in a series-parallel connection mode, and a single battery monitoring and managing device is additionally arranged to form an intermediate product of the battery cells and pack. The structure of the battery cell has to play roles in supporting, fixing and protecting the battery cell, and can be summarized into 3 major items: mechanical strength, electrical properties, thermal properties and fault handling capability.

SOC (State Of Charge): is the state of charge of the battery, i.e., the remaining capacity. SOC means the ratio of the amount of dischargeable charge to the amount of full charge after a battery is used for a period of time or stored for a long period of time.

SOH (State Of Health): refers to the state of health of the battery, i.e., the degree of performance degradation of the battery during use. SOH reflects the percentage of remaining capacity of a battery relative to its initial design capacity.

LLC resonant topology: the resonant cavity is formed by connecting two inductance devices and one capacitance device in series, wherein one inductance device is a resonant inductor Lr, the other inductance device is a transformer (primary inductance is Lm) and the other inductance device is a resonant capacitor Cr.

CAN (Controller Area Network) bus: is one of buses, and is one of the most widely used field buses internationally.

Along with the development of new energy sources, electric automobiles also use electric energy as driving energy. Because the energy demand of electric automobile is great, form the parallel operation system through the group of battery module to provide the energy for electric automobile through the parallel operation system. The parallel operation system mainly comprises an energy storage converter, a DC/DC unit, a BMS module, a battery pack and the like. The DC/DC unit, the BMS module and the battery pack form an independent battery module together, and the battery modules are connected to the BUS end of the energy storage converter in parallel to form a parallel operation system. The traditional parallel operation system adopts an average power control strategy, and under certain working conditions, the problem that the full-rated power charge/discharge cannot be realized exists. For example, when the electric quantity of a certain battery module is too low during discharging, the undervoltage protection is triggered to exit the parallel operation system, so that the discharging power is reduced. When the battery module is charged, the electric quantity of one battery module is earlier than that of other battery modules, and the battery module can not be shut down due to the need of quick response discharge, and the continuous charging can trigger the overvoltage protection of the battery cell. Therefore, how to equalize the power variation between the battery modules during charge and discharge is called a problem to be solved.

Based on the above, the embodiment of the invention provides a charging and discharging control method based on a parallel battery module and related equipment, wherein the current battery parameter and the total power are obtained, and the battery parameters of other battery modules in the parallel battery system are obtained to obtain the reference battery parameter, so that the current battery parameter and the reference battery parameter are subjected to power distribution through a power distribution model to determine the target power of the battery module in the charging process, and the target power distributed by the battery module is determined according to the battery parameters of each battery module, so that balanced power distribution is realized. When the power distribution is carried out according to the target power, the residual electric quantity is collected regularly to serve as the updated residual electric quantity, so that the current in the charging process of the battery module is adjusted according to the preset electric quantity range and the updated residual electric quantity, the sectional current limiting strategy is adopted, the current of the battery module in each time period is effectively controlled, the battery module in the parallel operation system is favorable to be filled at the similar moment, and the problem of overcharging of the battery is effectively solved.

Referring to fig. 1, a system architecture diagram based on an application of a method for controlling charge and discharge of a parallel battery module in an embodiment of the present invention is shown. It should be noted that the charge and discharge control method based on the parallel operation battery module is applied to the battery module 101 of the parallel operation system, and the parallel operation system includes at least two battery modules 101, an energy storage converter 102 and a junction box 103, each battery module 101 is electrically connected to the junction box 103, and each battery module 101 is connected to the BUS end of the energy storage converter 102 in parallel. The adapter box 103 is electrically connected to the energy storage converter 102 and the battery modules 101, and the adapter box 103 is responsible for collecting and forwarding data of each battery module 101. Therefore, the data of the battery module 101 is transmitted through the adapter case 103 to transmit the battery parameters of the battery module 101 to an external server. It should be noted that, the plurality of battery modules 101 are implemented through CAN bus communication, so as to implement mutual transmission of battery parameters between the battery modules 101 through the CAN bus.

Referring to fig. 2, fig. 2 is a flowchart illustrating a method for controlling charge and discharge based on a parallel battery module according to an embodiment of the present invention. In some embodiments, a battery module of a parallel operation system is applied to a battery module of a parallel operation system, and the embodiment of the invention discloses a battery module of a parallel operation system, which may include, but is not limited to, steps S201 to S205:

step S201, obtaining current battery parameters and total power of a parallel operation system;

step S202, current battery parameters are sent to a battery module in a parallel operation system, and the battery parameters sent by the battery module of the parallel operation system are received to obtain reference battery parameters;

step S203, performing power calculation on the total power, the current battery parameters and the reference battery parameters through a preset power distribution model to obtain target power;

step S204, charging and discharging are executed according to the target power, and the residual electric quantity in the charging process is collected periodically according to a preset time period, so that updated residual electric quantity is obtained;

step S205, current in the charging and discharging process is adjusted according to the preset electric quantity range and the updated residual electric quantity.

In step S201 to step S205 illustrated in this embodiment, the battery module obtains its own battery parameters to obtain current battery parameters, and obtains the total power of the entire parallel system, and simultaneously sends the current battery parameters to other battery modules of the parallel system, and receives the battery parameters from other battery modules in the parallel system to obtain reference battery parameters. Therefore, each battery module can carry out power distribution on the current battery parameter, the reference battery parameter and the total power through the power distribution model to obtain target power, so that the power of each battery module in the charging and discharging process can be distributed according to the requirement, and the charging and discharging operation is carried out according to the target power. Meanwhile, the battery module collects the residual electric quantity in a preset time period in a target power charging process to obtain updated residual electric quantity, and adjusts the current in the charging process according to the preset electric quantity range and the updated residual electric quantity, so that the current in the charging process of the battery module is effectively controlled, each battery module in the parallel operation system is guaranteed to be full at a similar moment, the problem of the battery process is effectively solved, and the power of the battery module in the charging and discharging processes is balanced.

In steps S201 to S202 of some embodiments, the current battery parameter is a battery parameter of the battery module itself, and if the current battery parameter is sent to other battery modules in the parallel system, the other battery modules define the current battery parameter as a reference battery parameter. It should be noted that, the reference battery parameters obtained from other battery modules are also the current battery parameters of other battery modules. Meanwhile, the total power of the parallel operation system is obtained, so that the amount of power required to be distributed by the battery module in the whole parallel operation system can be determined according to the total power to meet the total power demand. Specifically, the current battery parameters of each battery module are sent to other battery modules in the parallel operation system through the CAN bus.

For example, as shown in fig. 1, if the current battery module is a battery module #1, the battery module #1 collects its own battery parameters to obtain the current battery parameters, and sends the current battery parameters to the battery module #2, the battery module #3 and the battery module #4 through the CAN bus. And simultaneously receiving the battery parameters sent from the battery module #2, the battery module #3 and the battery module #4 to obtain the reference battery parameters. Therefore, the mutual transmission of battery parameters is realized through the CAN bus, each battery module only needs to acquire the current battery parameters of the battery module and the received reference battery parameters to calculate the power which CAN be distributed by the battery module, only needs to load a power distribution model on each battery module, does not need to rely on a server of a third party to distribute the power, reduces equipment connection and cost, ensures that the power distribution is simpler, and has lower equipment cost.

In some embodiments, the current battery parameters include: the current remaining power and the current battery state of health data, the reference battery parameters include: reference remaining power and reference battery state of health data. Note that, the current remaining power is SOC _n And the current battery state of health data is SOH _n . Because the residual electric quantity of each battery module is different, power is required to be distributed according to different residual electric quantities in the charging and discharging process, and power distribution according to the requirements is realized, so that the battery modules in the parallel operation system can realize power balance in the charging and discharging process, and the process conditions of partial battery modules are reduced, or the conditions of partial battery modules are not full. Meanwhile, as the service time of the battery module is prolonged, the battery module has aging conditions, so that the power distribution of the residual electric quantity of the battery has deviation, and the battery health state data is obtained, so that the deviation of the power distribution caused by the aging of the battery is compensated according to the battery health state data, and the power distribution is more accurate.

In some embodiments, referring to fig. 3, step S203 may include, but is not limited to, steps S301 to S305:

step S301, summarizing the reference residual capacity and the current residual capacity through a power distribution model to obtain total residual capacity;

Step S302, calculating the ratio of the current residual electric quantity to the total residual electric quantity through a power distribution model to obtain a residual electric quantity ratio;

step S303, summarizing the reference battery health status data and the current battery health status data through a power distribution model to obtain total battery health status data;

step S304, calculating the ratio of the current battery state of health data to the total battery state of health data through a power distribution model to obtain a state of health ratio;

and step S305, performing power distribution on the remaining capacity ratio, the health state ratio and the total power through a power distribution model to obtain target power.

In step S301 of some embodiments, the reference remaining power and the current remaining power are first assembled into a total remaining power by a power distribution model. It should be noted that, there are a plurality of reference remaining capacities, the reference remaining capacity is the remaining capacity of other battery modules in the parallel operation system, the total remaining capacity is obtained by summing the plurality of reference remaining capacities and the current remaining capacity, and the total remaining capacity is the remaining capacity of the whole parallel operation system at the current moment.

For example, if the current discharge is the discharge, the current remaining power at the time of the discharge is SOC _n Then the total remaining capacity calculation formula at the time of discharge is shown as formula (1):

SOC _{total (S)} ＝SOC ₁ +SOC ₂ +…+SOC _n +…+SOC _N (1)

If the current charge is the charging, the current residual electric quantity in the charging is SOC ^* _n Then the calculation formula of the total remaining capacity at the time of charging is as shown in formula (2):

SOC ^* ₁ +SOC ^* ₂ +…+SOC ^* _n +…+SOC ^* _N (2)

wherein N represents the total number of battery modules in the parallel operation system, N represents the number of the current battery module and SOC ^* ＝1-SOC。

In step S302 of some embodiments, after the calculation of the total remaining power is completed, the current remaining power is divided by the total remaining power by the power distribution module to obtain a remaining power ratio, and the remaining power ratio is the power ratio of the entire parallel operation system, so the remaining power ratio can be used as main reference data of power distribution.

For example, if discharging, the formula of dividing the current remaining power at the time of discharging by the total remaining power is shown as formula (3):

if the battery is charged, the formula of dividing the current electric quantity by the total residual electric quantity during charging is shown as formula (4):

in steps S303 to S305 of some embodiments, when the battery is aged, power distribution imbalance may be caused by only the power distribution of the remaining battery power. Therefore, the power compensation is performed according to the battery state of health data, so that the power distribution is more accurate. The method comprises the steps of summing battery health status data of all battery modules in a parallel operation system to obtain total battery health status data, and calculating the ratio of the current battery health status data and the total battery health status data of each battery module to obtain a health status ratio, wherein the health status ratio represents the duty ratio of the current battery module in the whole parallel operation system.

For example, during a discharging process or a charging process, the state of health ratio is obtained by dividing the current battery state data by the total battery state data as shown in formula (5):

in step S305 of some embodiments, after the remaining power ratio and the health status ratio are calculated, the total power is distributed to each battery module by using the remaining power ratio and the health status ratio as distribution reference data through a power distribution model, so as to obtain the target power.

In steps S301 to S305 illustrated in this embodiment, a remaining power ratio is obtained by calculating a remaining power ratio of the current battery module in the entire parallel operation system, and a health status ratio is obtained by calculating a duty ratio of battery health status data of the current battery module in the entire parallel operation system. And finally, distributing total power according to the ratio of the residual electric quantity and the visible state ratio, realizing power distribution in the charging and discharging process, and carrying out power compensation by considering battery aging, so that the power distribution is more accurate.

In some embodiments, referring to fig. 4, step S305 may include, but is not limited to including, step S401 to step S402:

step S401, performing sum calculation on the ratio of the residual electric quantity and the ratio of the health state through a power distribution model to obtain a power distribution ratio;

Step S402, dividing power distribution proportion and total power into power through a power distribution model to obtain target power; the formula for dividing the power distribution proportion and the total power by the power distribution model is as follows:wherein P is _l For power distribution ratio, P _{_all} Is the total power.

In step S401 of some embodiments, the remaining capacity ratio is a remaining capacity ratio of the current battery module in the entire parallel operation system, and the health status ratio is a health status data ratio of the current battery module in the entire parallel operation system. And the power distribution ratio is obtained by summing the ratio of the residual electric quantity and the ratio of the health state, so that the battery aging problem is considered in the power distribution ratio, and the power distribution is more accurate based on the power distribution ratio.

In step S402 of some embodiments, the target power is obtained by multiplying the power allocation proportion and the total power, so that the calculation of the target power is easy. Specifically, a formula of the power distribution model for dividing the power distribution ratio and the total power is shown in a formula (6):

wherein P is _l For power distribution ratio, P _{_all} Is the total power, and during the discharging process, the power distribution ratio P _l ＝r _SOC +r _SOH If charging is performed, the power distribution ratio

In steps S401 to S402 illustrated in the present embodiment, by adding the remaining power ratio and the health status ratio as the power distribution ratio, the calculated power distribution ratio is more accurate. Therefore, the target power of the battery module is calculated based on the power distribution ratio and the total power, so that the power distribution not only considers the remaining capacity ratio but also considers the battery aging problem, and the target power distributed by the battery module is more accurate.

In step S204 of some embodiments, after each battery module calculates the target power that can be allocated by itself, charging or discharging is performed according to the target power, so as to dynamically allocate the power in the charging or discharging process according to the remaining capacity of the battery module and the battery health status data, so as to ensure that the parallel operation system can charge/discharge at the maximum rated power at any time, and compensate the influence caused by the battery aging to a certain extent. Although the power of each battery module is dynamically distributed, it is difficult for the battery modules to be filled at similar times. The method comprises the steps of collecting the residual electric quantity in the charging process according to a preset time period to obtain updated residual electric quantity, and accurately controlling the current of the battery modules in the charging process according to the updated residual electric quantity as a reference for current control, so that each battery module is guaranteed to finish charging at a similar moment.

Referring to fig. 5, in some embodiments, step S205 may include, but is not limited to, steps S501 to S503:

step S501, if the updated residual power is greater than the upper limit value of the preset power range, adjusting the current to the lower limit value of the preset current range;

step S502, if the updated residual electric quantity is within the preset electric quantity range, controlling the current within the preset current range;

in step S503, if the updated remaining power is smaller than the lower limit value of the preset power range, the current is adjusted to the upper limit value of the preset current range.

In step S501 of some embodiments, the preset power range is a power range set in advance, and is used as a reference power range for whether the battery module is overcharged. It should be noted that the control of the current is implemented by a controller in the DC-DC unit, and the DC-DC unit adopts a control strategy (except for a fault) that does not shut down. And comparing the updated residual electric quantity with a preset electric quantity range through a controller in the DC-DC unit, and if the updated residual electric quantity is larger than the upper limit value of the preset electric quantity range, representing that the battery module is about to be fully charged, so that the current of the battery module is limited to be at the lower limit value of the preset current range, and other battery modules can be charged more.

In step S502 of some embodiments, if the updated remaining capacity is within the preset capacity range, it is indicated that the battery module will be charged, but the current of the battery module needs to be limited within the preset current range for a certain distance from the full charge, so that the battery module is reduced from completing charging too fast. By limiting the current of the battery modules within a preset current range, other battery modules which are not fully charged can be charged more, so that each battery module in the parallel operation system can be fully charged at a similar moment.

In step S503 of some embodiments, if the updated remaining capacity is smaller than the lower limit value of the preset capacity range, it is indicated that the current remaining capacity of the battery module is full of a certain distance, so that the limiting current is within the preset current range, so that the battery module can be charged quickly, and charging can be completed at a time similar to that of other battery modules. It should be noted that, when the updated remaining power is smaller than the lower limit value of the preset power range, in order to avoid repeated switching frequency, the battery module will exit the current adjustment strategy and enter the normal frequency modulation mode, and current adjustment is only performed when the updated remaining power is larger than the lower limit value of the preset power range, so as to prevent frequent current switching from affecting the stability of the parallel operation system.

For example, if the preset power range is 97% -99%, the preset current range is 0.5-3A. If the updated residual electric quantity is more than 99%, modulating the switching frequency of the battery module into an LLC topological structure, designing a DC-DC unit to be the highest frequency, and controlling the charging current to be limited to 0.5A; if the updated residual electric quantity is within 97% -99%, controlling the charging current to be limited within 0.5-4A; if the updated remaining power is less than 97%, the current for controlling charging is limited to 4A. Therefore, through the current regulation of the stage type, the minimum current is limited when the residual electric quantity is high, and the maximum current is limited when the residual electric quantity is low, so that each battery module in the parallel operation system can be fully charged in similar time, and the problem that the unfilled battery module cannot be charged or is overcharged because a certain battery module is fully charged first can be avoided.

In some embodiments, the preset power range includes: a first electrical quantity range, a second electrical quantity range, and a third electrical quantity range; the first electric quantity range is smaller than the second electric quantity range, and the second electric quantity range is larger than the third electric quantity range; the preset current range includes: the first current value is greater than the second current value, and the second current value is greater than the third current value. It should be noted that, through setting up three electric quantity scope to and every electric quantity scope sets up corresponding current value to be convenient for charge according to updating which electric quantity scope that the surplus electric quantity falls into sets up corresponding current value, realize the current regulation in stages, make the current regulation more accurate.

Referring to fig. 6, in some embodiments, step S503 may include, but is not limited to including, step S601 to step S603:

step S601, if the updated remaining power is within the first power range, limiting the current to a first current value;

step S602, if the updated remaining power is within the second power range, limiting the current to a second current value;

in step S603, if the updated remaining power is within the third power range, the current is limited to the third current value.

In steps S601 to S603 of some embodiments, when the updated remaining capacity is within the first capacity range, it is indicated that the remaining capacity of the battery module is higher, and the charging current needs to be limited. Because the first electric quantity range is smaller than the second electric quantity range and the third electric quantity range, the limiting current is in the first current value, and the first current value is larger than the second current value and the second current value, so that the battery modules can be leveled with the battery modules with higher residual electric quantity in the charging process, and each battery module in the parallel operation system can be fully charged at a similar moment. If the updated residual electric quantity is in the second electric quantity range, the current is limited to a second current value, and if the updated residual electric quantity is in the third electric quantity range, the current is limited to a third current value. Therefore, three electric quantity ranges are set so as to pointedly limit the current value, realize the current of charging to be regulated in stages, and enable each battery module to be fully charged at similar moments.

For example, if the first power range is 97% -98%, the second power range is 98% -98.5%, and the third power range is 98.5-99%; the first current value is 3A, the second current value is 2A, the third current value is 1A, and the updated residual electric quantity is SOC _Updating . If the SOC is 97 percent or less _Updating Less than 98%, and limiting the charging current of the battery module to 3A; if the SOC is 98 percent or less _Updating Less than 98.5%, and the charging current of the battery module is limited to 2A; if the SOC is 98.5 percent or less _Updating And < 99%, and the charging current of the battery module is limited to 1A. Therefore, the charging current is adjusted in stages, so that the plurality of battery modules are fully charged at similar moments under the condition that the overcharge protection is not triggered is ensured.

In other embodiments, the ac/dc conversion of the battery module is mainly implemented by an energy storage converter, and the energy storage converter is connected between the battery module and the power grid, and the device for implementing the bidirectional conversion of electric energy by the energy storage converter can control the charging and discharging processes of the battery module to perform ac/dc conversion, so that ac can be converted into dc under the condition of no power grid.

In the steps S601 to S603 illustrated in the embodiment, by setting the current control in stages, the current of the battery module is controlled in a targeted manner, so that the battery module can be fully charged at a similar time, and the problem of overcharging of the battery module is effectively solved.

In some embodiments, referring to fig. 7, a method for controlling charge and discharge based on a parallel battery module may further include, but is not limited to, steps S701 to S703:

step S701, performing difference calculation on the current voltage value and the reference voltage value to obtain a voltage difference value;

step S702, if the voltage difference is greater than the preset voltage difference range, the parallel operation system is exited;

in step S703, if the voltage difference is within the voltage difference range, the parallel operation system is entered.

In steps S701 to S703 illustrated in the present embodiment, when the voltage difference between the battery modules in the parallel operation system is too large, a problem of circulation occurs. Obtaining a voltage difference value by calculating the difference value between the current voltage value and the reference voltage value, and enabling the battery module to exit the parallel operation system when the voltage difference value is larger than the voltage difference range; if the voltage difference is within the voltage difference range, the circulation problem does not occur between the battery modules, and the battery modules are brought into the parallel operation system. Therefore, by adding the voltage difference of the battery modules in the dynamic monitoring parallel operation system, the problem of circulation among the battery modules caused by the gain limitation of the LLC topological structure can be solved.

Specifically, since the DC-DC unit adopts an LLC topology, and the gain limitation of the LLC topology may cause a problem of circulation between battery modules. Therefore, by calculating the voltage difference between the battery modules, if the voltage difference is larger than the voltage difference range, the battery modules cannot realize the parallel operation function, and the other battery modules on the CAN bus are affected. Therefore, when the voltage difference is larger than the voltage difference range, the battery module is withdrawn from the parallel operation system, and charging/discharging actions are performed at intervals, so that the battery module with large voltage difference does not influence other battery modules, and the battery module cannot be used all the time due to the overlarge voltage difference, and resource waste is avoided. When the battery module exiting the parallel operation system is normally discharged, the voltage difference between the battery module and other battery modules is reduced, and the voltage difference is within the voltage difference range, which indicates that the battery module meets the parallel operation system condition, and the battery module can continue to be in parallel operation, so that the battery module enters the parallel operation system.

Referring to fig. 8, an embodiment of the present application further provides a battery module, which can implement the above-mentioned charge and discharge control method based on a parallel operation battery module, where the battery module is disposed in a parallel operation system, and the battery module includes:

an obtaining module 801, configured to obtain current battery parameters and total power;

the transmission module 802 is configured to send the current battery parameter to a battery module in the parallel operation system, and receive the battery parameter sent by the battery module of the parallel operation system to obtain a reference battery parameter;

the power calculation module 803 is configured to perform power calculation on the total power, the current battery parameter and the reference battery parameter through a preset power distribution model, so as to obtain a target power;

the charge-discharge control module 804 is configured to perform charge-discharge according to the target power, and periodically collect a remaining power of the charging process according to a preset time period, so as to obtain an updated remaining power;

the current adjustment module 805 is configured to adjust the current in the charging and discharging process according to the preset power range and the updated remaining power.

The specific implementation of the charging and discharging control device based on the parallel battery module is basically the same as the specific embodiment of the charging and discharging control method based on the parallel battery module, and is not repeated here.

In some embodiments, referring to fig. 9, the battery module further includes:

a battery pack 901;

a DC-DC unit 902, wherein the end of the DC-DC unit 902 is connected with a battery pack 901;

a BMS module 903, the BMS module 903 electrically connecting the DC-DC unit 902 and the battery pack 901; wherein the DC-DC unit 902 includes: the low-voltage side unit 9021, the high-voltage side unit 9022, the resonance unit 9023 and the transformer 9024, wherein the low-voltage side unit 9021 is electrically connected with one end of the transformer 9024, the other end of the transformer 9024 is connected with one end of the resonance unit 9023, and the other end of the resonance unit 9023 is connected with the high-voltage side unit.

In some embodiments, referring to fig. 10, the low-voltage side unit 9021 includes: the first capacitor C1, the first MOS transistor Q1, the second MOS transistor Q2, the third MOS transistor Q3 and the fourth MOS transistor Q4; the high-pressure side unit 9022 includes: the second capacitor C2, the fifth MOS transistor Q5, the sixth MOS transistor Q6, the seventh MOS transistor Q7 and the eighth MOS transistor Q8. One end of the first capacitor C1 is connected with the source electrode of the first MOS tube, and the other end of the first capacitor C1 is connected with the drain electrode of the first MOS tube; the source electrode of the first MOS tube Q1 is connected with the source electrode of the third MOS tube Q3 and is connected with a power supply, the drain electrode of the first MOS tube Q1 is connected with the transformer 9024, the drain electrode of the second MOS tube Q2 is connected with the source electrode of the first MOS tube Q1, and the source electrode of the fourth MOS tube Q4 is connected with the drain electrode of the third MOS tube and the transformer 9024. The resonance unit 9023 includes: the resonant inductor Lr and the resonant capacitor Cr are connected with the transformer 9024 at one end and the resonant capacitor Cr at the other end, the drain electrode of the fifth MOS transistor Q5 and the source electrode of the sixth MOS transistor Q6 are connected with the other end of the resonant capacitor Cr, the drain electrode of the seventh MOS transistor Q7 and the source electrode of the eighth MOS transistor Q8 are connected with each other, one end of the second capacitor C2 is connected with the source electrode of the seventh MOS transistor Q7, and the other end is connected with the drain electrode of the eighth MOS transistor Q8. Therefore, by constructing the LLC resonant topology structure as the DC-DC unit, and the charge and discharge control of the battery module is realized by the DC-DC unit, only the closing of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3, the fourth MOS tube Q4, the fifth MOS tube Q5, the sixth MOS tube Q6, the seventh MOS tube Q7 and the eighth MOS tube Q8 is controlled, so that the charge and discharge control and the current regulation of the battery module are realized, and the charge and discharge control and the current regulation of the battery module are simpler.

Referring to fig. 1, the embodiment of the application further provides a parallel operation system, where the parallel operation system includes: a battery module 101, an energy storage converter 102 and a junction box 103; the battery module 101 is used for executing the above-mentioned charge and discharge control method based on the parallel battery module; the energy storage converter 102 is provided with a connecting end, and is connected with the battery module 101 through the connecting end; the adapter box 103 is electrically connected between the battery module 101 and the energy storage converter 102, and is used for collecting and forwarding battery parameters of each battery module.

The energy storage converter 102 includes: the inverter INV and pv are formed by arranging 4 battery modules including a battery module #1, a battery module #2, a battery module #3 and a battery module #4 and connecting the 4 battery modules to the BUS end of the energy storage inverter PCS as shown in figure 1, so that the parallel operation effect of the battery modules is achieved. It should be noted that, control of the parallel operation system is realized through communication of the CAN bus.

The embodiment of the application also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program realizes the charging and discharging control method based on the parallel battery module when being executed by a processor.

The memory, as a non-transitory computer readable storage medium, may be used to store non-transitory software programs as well as non-transitory computer executable programs. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory optionally includes memory remotely located relative to the processor, the remote memory being connectable to the processor through a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The embodiments described in the embodiments of the present application are for more clearly describing the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application, and as those skilled in the art can know that, with the evolution of technology and the appearance of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

It will be appreciated by those skilled in the art that the technical solutions shown in the figures do not constitute limitations of the embodiments of the present application, and may include more or fewer steps than shown, or may combine certain steps, or different steps.

The above described apparatus embodiments are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Those of ordinary skill in the art will appreciate that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof.

The terms "first," "second," "third," "fourth," and the like in the description of the present application and in the above-described figures, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It should be understood that in this application, "at least one" means one or more, and "a plurality" means two or more. "and/or" for describing the association relationship of the association object, the representation may have three relationships, for example, "a and/or B" may represent: only a, only B and both a and B are present, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b or c may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the above-described division of units is merely a logical function division, and there may be another division manner in actual implementation, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in part or all of the technical solution or in part in the form of a software product stored in a storage medium, including multiple instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of the various embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing a program.

Preferred embodiments of the present application are described above with reference to the accompanying drawings, and thus do not limit the scope of the claims of the embodiments of the present application. Any modifications, equivalent substitutions and improvements made by those skilled in the art without departing from the scope and spirit of the embodiments of the present application shall fall within the scope of the claims of the embodiments of the present application.

Claims

1. The charging and discharging control method based on the parallel operation battery module is characterized by being applied to a battery module of a parallel operation system, and comprises the following steps:

2. The parallel battery module-based charge and discharge control method according to claim 1, wherein the current battery parameters include: current remaining power and current battery state of health data, the reference battery parameters include: reference remaining power and reference battery state of health data; the power calculation is performed on the total power, the current battery parameter and the reference battery parameter through a preset power distribution model to obtain a target power, including:

3. The method for controlling charge and discharge based on a parallel battery module according to claim 2, wherein the performing power distribution on the remaining power ratio, the health status ratio and the total power by the power distribution model to obtain the target power comprises:

performing sum calculation on the remaining electric quantity ratio and the health state ratio through the power distribution model to obtain a power distribution ratio;

Dividing the power distribution proportion and the total power into power by the power distribution model to obtain the target power; the formula for dividing the power distribution ratio and the total power by the power distribution model is as follows:wherein P is _l For power distribution ratio, P _{_} Is the total power.

4. The parallel battery module-based charge and discharge control method according to any one of claims 1 to 3, wherein the adjusting the current of the charge and discharge process according to the preset power range and the updated remaining power includes:

5. The method for controlling charge and discharge based on a parallel battery module according to claim 4, wherein the preset power range includes: a first electrical quantity range, a second electrical quantity range, and a third electrical quantity range; the first electric quantity range is smaller than the second electric quantity range, and the second electric quantity range is larger than the third electric quantity range; the preset current range includes: a first current value, a second current value, and a third current value, the first current value being greater than the second current value, the second current value being greater than the third current value; and if the updated remaining capacity is within the preset capacity range, controlling the current within the preset current range, including:

6. A parallel battery module-based charge and discharge control method according to any one of claims 1 to 3, wherein the current battery parameter further includes a current voltage value, the reference battery parameter further includes a reference voltage value, and after the adjusting the current of the charge and discharge process according to the preset power range and the updated remaining power, the method further includes:

7. The utility model provides a battery module, its characterized in that, battery module sets up in the parallel operation system, battery module includes:

8. The battery module according to claim 7, wherein the battery module comprises:

a battery pack;

the DC-DC unit end is connected with the battery pack;

9. A parallel operation system, characterized in that the parallel operation system comprises:

a battery module for performing the parallel battery module-based charge and discharge control method according to any one of claims 1 to 6;

10. A computer-readable storage medium storing computer-executable instructions for causing a computer to perform the parallel battery module-based charge and discharge control method according to any one of claims 1 to 6.