A lithium ion battery module with equalization capability and an equalization method

Abstract

The application provides a lithium ion battery module with equalization capability and an equalization method, which comprises a shell, n groups of cell string groups are arranged in the shell and are connected in parallel between the cell string groups; the cell string group comprises an embedded digital energy network card and a cell string, the cell string is electrically connected with the embedded digital energy network card, the embedded digital energy network cards can communicate with each other, and the cell string is composed of a plurality of cells connected in series; the embedded digital energy network card can collect voltage and current information of the cell string, when the battery module is in a charging or discharging state, the embedded digital energy network card can adjust the charging or discharging state of each group of cell strings according to the collected information; when the battery module is discharged or charged, the working state of each group of cell strings can be controlled according to the voltage and current information of the cell string, the voltage balance between the cell strings in the parallel direction is ensured, and the service life of the battery module is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy power, in particular to a lithium ion battery module with balancing capability and a balancing method. BACKGROUND

[0002] As a high-performance energy storage device, lithium iron phosphate battery packs have been widely used in communication fields, especially in key communication energy storage scenarios such as communication base stations and central machine rooms, due to their high safety performance, strong stability, high energy conversion efficiency, and long cycle life. These battery packs are usually composed of multiple battery modules and a set of battery management systems (BMS) that work together to ensure the stability and reliability of power supply.

[0003] With the continuous progress of communication technology and the increasing diversification of application scenarios, more challenges have been posed to the design of lithium iron phosphate battery packs. On the one hand, in order to meet the stringent requirements of different devices for battery energy density and space utilization, the design of battery systems needs to be more compact and efficient; on the other hand, considering cost-effectiveness and the convenience of operation and maintenance, the production and maintenance costs of battery packs also need to be effectively controlled.

[0004] Under such circumstances, the traditional internal cell connection method of battery modules - one-to-many series (i.e., one parallel group contains multiple series of cells) has gradually become difficult to meet the needs of battery manufacturers and end users. In order to improve the overall performance and flexibility of battery packs, two-to-many series or even multi-to-multi series of cell combinations have been widely used in battery modules. This design not only improves the energy density and power output capability of battery packs, but also enhances the redundancy and reliability of the system.

[0005] However, with the complication of cell combination methods, the balancing problem between cells inside the battery module has become increasingly prominent, especially in the parallel direction. Due to the possible small performance differences and manufacturing process errors between cells, their voltage changes during charging and discharging are inconsistent. This voltage imbalance not only affects the overall performance and life of the battery pack, but also may cause safety problems such as overheating, short circuit, etc.

[0006] Existing technologies often use passive balancing methods to balance the voltage of cells inside the battery module, such as patent CN107516922A. However, this method has small balancing current, weak balancing capability, and also causes power waste through balancing resistors.

[0007] Therefore, how to solve the voltage balancing problem between parallel direction cell strings during discharging or charging of the battery module has become a key technical problem to be solved in the design and maintenance of lithium iron phosphate battery packs. SUMMARY

[0008] Therefore, the present application aims to provide a lithium ion battery module with equalization capability and an equalization method to solve the problem that the battery module cannot effectively ensure the voltage balance between the cell strings in parallel direction when discharging or charging in the prior art.

[0009] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0010] A lithium ion battery module with equalization capability comprises a shell, and n groups of cell string groups are arranged in the shell and connected in parallel between the cell string groups.

[0011] The cell string group comprises embedded digital energy network cards and cell strings, the cell strings are electrically connected with the embedded digital energy network cards, the embedded digital energy network cards can communicate with each other, and the cell strings are composed of a plurality of cell strings in series.

[0012] The embedded digital energy network card can collect voltage and current information of the cell string, and when the battery module is in a charging or discharging state, the embedded digital energy network card can adjust the charging or discharging state of each group of cell strings according to the collected information.

[0013] This arrangement can not only enhance the voltage consistency between each group of cell strings and ensure the voltage balance between each group of cell strings in parallel direction when the battery module is discharging or charging, but also can avoid overcharging or discharging of the cell string, reduce the maintenance cost in the later period, prolong the service life of the battery module, and has no energy loss.

[0014] Further, the embedded digital energy network card is provided with a voltage sampling circuit, a current sampling circuit, a BTU circuit and a main control chip, the voltage sampling circuit is used to collect voltage information of the cell string and send it to the main control chip, the current sampling circuit is used to collect current information of the cell string and send it to the main control chip, the current information includes current value and current direction, the BTU circuit is used to collect voltage, current and temperature information of the cell and send it to the main control chip, the main control chip adjusts the charging or discharging state of each group of cell strings according to the voltage and current information of each group of cell strings, and can control the BTU circuit to perform equalization adjustment on the cell with abnormal voltage according to the voltage and current information of the cell.

[0015] This arrangement can reduce the performance degradation of the battery module and prolong the service life of the battery module.

[0016] Further, the embedded digital energy network card of the first group of cell string groups is a host, and when the battery module is in a charging or discharging state, the host can adjust the charging or discharging state of each group of cell strings according to the voltage and current information of each group of cell strings.

[0017] This design can also reduce the complexity of the battery management system, while improving the stability and efficiency of the system.

[0018] Further, the shell is provided with a total + terminal and a total - terminal, the embedded digital energy network card is provided with a battery + terminal, a battery - terminal and a power + terminal, the positive electrode of the battery cell string is electrically connected with the battery + terminal, the negative electrode of the battery cell string is respectively electrically connected with the battery - terminal and the total - terminal, the negative electrode terminals of each group of battery cell strings are electrically connected, and the total + terminal is respectively electrically connected with the power + terminal of each group of battery cell strings.

[0019] By electrically connecting the battery + terminal, the battery - terminal and each group of battery cell strings, the number of battery cell strings can be increased or decreased as needed without large-scale modification, which is highly adaptable and facilitates the expansion and customization of the battery module.

[0020] Further, the embedded digital energy network card includes a driving optocoupler, a power MOS and a CAN-1, the power MOS includes MOS1 and MOS2, the drain electrode of the MOS1 is connected with the positive electrode of the battery cell string, the source electrode of the MOS1 is connected with the source electrode of the MOS2, the drain electrode of the MOS2 is connected with the power + terminal, and the CAN-1 is used for communication between the embedded digital energy network cards inside the battery module.

[0021] This design provides an efficient, safe and stable battery management system, which can effectively improve the charge and discharge control precision of the battery module, optimize the energy transmission efficiency, improve the expansibility and maintainability of the system, and enhance the safety and reliability of the battery management system.

[0022] Further, the shell is provided with an RJ45 interface 1 and an RJ45 interface 2, and the embedded digital energy network card 1 includes an RS485-11 / CAN-11, which is respectively electrically connected with the RJ45 interface 1 and the RJ45 interface 2.

[0023] This design not only simplifies the wiring and reduces the cost, but also enhances the reliability and expansibility of the system, and the multi-protocol support and standardized interface design make the system have strong compatibility and good adaptability, which can meet the requirements of complex battery management systems and improve the intelligentization and remote monitoring capability of the system.

[0024] An equalization method for the lithium ion battery module with equalization capability, comprising the steps of:

[0025] S1: detecting the direction information of the current in the battery module, the voltage and current information of the battery cell string, and the voltage and current information of the battery cell, and entering S2;

[0026] S2: judging the state of the battery module according to the detected information, when the battery module is in standby state, entering S3, when the battery module is in discharging state, entering S4, when the battery module is in charging state, entering S5;

[0027] S3: executing standby mode, balancing the cells, entering S1;

[0028] S4: executing discharging mode, discharging the battery module, entering S1;

[0029] S5: executing charging mode, charging the battery module, entering S1.

[0030] This balancing method can execute different processing strategies according to the state of the battery module, and this dynamic adaptation capability can improve the management accuracy of the battery module, avoid cell string or cell overcharge or overdischarge, thereby prolonging the service life of the battery module.

[0031] Further, step S3 includes:

[0032] S31: detecting the voltage values of each cell in the cell string, setting the voltage value of the cell with the highest voltage as U 高 , setting the voltage value of the cell with the lowest voltage as U 低 , and entering S32;

[0033] S32: detecting and judging whether U 高 > U 设 , if yes, entering S33, if no, entering S1;

[0034] S33: detecting and judging whether U 高 -U 低 > U 差 , if yes, entering S34, if no, entering S1;

[0035] S34: passively balancing the cell with the highest voltage, when U 高 -U 低 ≤ U 差 , entering S31;

[0036] Wherein, in any group of cell strings, U 高 is the voltage value of the cell with the highest voltage, U 低 is the voltage value of the cell with the lowest voltage, U 设 is the low voltage setting value of the cell, and U 差 is the set difference between the highest voltage value and the lowest voltage value of the cell.

[0037] This method can dynamically process according to the real-time detected voltage difference, so that each cell will not overcharge or overdischarge, and the working stability of the entire battery module is improved.

[0038] Further, the step S4 comprises:

[0039] S41: detecting and judging whether I 放 ≤ (m / n) x I 额放 , if yes, entering S42;

[0040] S42: detecting voltage values of n groups of battery cell strings every interval t, and sorting n groups of battery cell strings according to the high and low of voltage values, selecting m groups of battery cell strings from high to low to discharge, cutting out the remaining n-m groups of battery cell strings, and entering S43;

[0041] S43: detecting and judging whether the voltage value of a battery cell string in m groups of battery cell strings is lower than the set over-discharge value, if yes, entering S44, if no, entering S41;

[0042] S44: cutting out the battery cell string with the voltage value lower than the set over-discharge value, and entering S45;

[0043] S45: detecting and judging whether the number of cut-out battery cell strings is less than n-m, if yes, entering S41, if no, controlling the battery cell strings not cut out to discharge at the same time, and entering S46;

[0044] S46: detecting and judging whether the voltage value of a battery cell string in the battery cell string participating in discharging is lower than the set over-discharge value, if yes, the battery module stops discharging, if no, entering S41;

[0045] Wherein, in the battery module, m is the set value of the number of battery cell strings simultaneously performing dynamic equalization adjustment, n is the total number value of battery cell strings, m < n, I 放 is the discharge current value of the battery module, I 额放 is the rated discharge current value of the battery module, and t is the time interval length of detection.

[0046] The control method can improve the voltage consistency between each group of battery cell strings, improve the discharge capacity of the battery module, avoid over-discharge of the battery cell string, and prolong the service life of the battery module.

[0047] Further, the step S5 comprises:

[0048] S51: detecting and judging whether I 充 ≤ (m / n) x I 额充 , if yes, entering S52;

[0049] S52: detecting voltage values of n groups of battery cell strings every interval t, and sorting n groups of battery cell strings according to the high and low of voltage values, selecting m groups of battery cell strings from low to high to charge, cutting out the remaining n-m groups of battery cell strings, and entering S53;

[0050] S53: Detect and determine whether the voltage value of the battery string in the m groups of battery strings is higher than the set overcharge value, if yes, go to S54, if no, go to S51;

[0051] S54: Cut out the battery string with the voltage value higher than the set overcharge value, and go to S55;

[0052] S55: Detect and determine whether the number of cut-out battery strings is less than n-m, if yes, go to S51, if no, control the battery strings that have not been cut out to charge at the same time, and go to S56;

[0053] S56: Detect and determine whether the voltage value of the battery string participating in charging is higher than the set overcharge value, if yes, the battery module stops charging, if no, go to S51;

[0054] Wherein, in the battery module, m is the set value of the number of battery strings for simultaneous dynamic balancing adjustment, n is the total number of battery strings, m < n, I 放 is the charging current value of the battery module, I 额放 is the rated charging current value of the battery module, and t is the time interval length of detection.

[0055] This control method can improve the voltage consistency between each group of battery strings, improve the power storage capacity and charging efficiency of the battery module, and also avoid overcharging of the battery string, prolong the service life of the battery module.

[0056] Compared with the prior art, the lithium ion battery module with balancing capability and the balancing method have the following advantages:

[0057] 1) When the battery module is discharging or charging, the voltage consistency between each group of battery strings can be improved, the voltage balance between each group of battery strings in parallel direction can be ensured, overcharging or overdischarging of the battery string can be avoided, the maintenance cost in later period can be reduced, the service life of the battery module can be prolonged, and there is no energy loss;

[0058] 2) Dynamic processing can be performed according to the real-time detected voltage difference, so that each battery in the battery string will not be overcharged or overdischarged, and the working stability of the entire battery module is improved;

[0059] 3) The working state of each group of battery strings can be managed centrally, the overall optimization control of the entire battery module can be realized, the complexity of the battery module management is reduced, and the stability and efficiency of the battery module are improved. BRIEF DESCRIPTION OF DRAWINGS

[0060] Fig. 1 is a structural schematic diagram of the lithium ion battery module described in the embodiment of the application;

[0061] Fig. 2The structural schematic diagram of the embedded digital energy network card. DETAILED DESCRIPTION

[0062] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings. Embodiment 1

[0063] As shown in the drawings, a lithium ion battery module with balancing capability comprises a shell, n groups of cell string groups are arranged in the shell, and the cell string groups are connected in parallel between them; Figs. 1-2

[0064] The cell string group comprises an embedded digital energy network card and a cell string, the cell string is electrically connected with the embedded digital energy network card, the embedded digital energy network cards can communicate with each other, and the cell string is composed of a plurality of cells connected in series.

[0065] The embedded digital energy network card can collect voltage and current information of the cell string, when the battery module is in a charging or discharging state, the embedded digital energy network card can adjust the charging or discharging state of each group of cell strings according to the collected information.

[0066] Specifically, the embedded digital energy network card can detect the voltage of each group of cell strings in real time, dynamically adjust the charging and discharging state of the cell string, when the battery module is in a discharging state, the cell string with a relatively high voltage value is discharged first, and the cell string with a relatively low voltage value is discharged later, when the battery module is in a charging state, the cell string with a relatively low voltage value is charged first, and the cell string with a relatively high voltage value is charged later. This setting can not only enhance the voltage consistency between each group of cell strings and ensure the voltage balance between each group of cell strings in the parallel direction when the battery module is discharging or charging, but also can avoid overcharging or discharging of the cell string, reduce the maintenance cost in the later period, prolong the service life of the battery module, and has no energy loss.

[0067] Preferably, the cell string is composed of 20 cells connected in series.

[0068] Preferably, the structure of each embedded digital energy network card is the same.

[0069] ​As a preferred example of the present application, the embedded digital energy network card is provided with a voltage sampling circuit, a current sampling circuit, a BTU circuit and a master control chip, the voltage sampling circuit is used to collect the voltage information of the battery cell string and send it to the master control chip, the current sampling circuit is used to collect the current information of the battery cell string and send it to the master control chip, the current information includes the current value and the direction of the current, the BTU circuit is used to collect the voltage, current and temperature information of the battery cell and send it to the master control chip, the master control chip adjusts the charging or discharging state of each group of battery cell strings according to the voltage and current information of each group of battery cell strings, and can control the BTU circuit to balance and adjust the battery cell with abnormal voltage according to the voltage and current information of the battery cell.

[0070] Specifically, the master control chip adjusts the charging or discharging state of each group of battery cell strings according to the voltage and current information of each group of battery cell strings, which can ensure the voltage consistency of the battery cell string during charging or discharging, and the BTU circuit can passively balance and adjust the battery cell with high voltage in the battery cell string to prevent individual battery cell from overcharging or overdischarging. This design can reduce the performance degradation of the battery module and prolong the service life of the battery module.

[0071] As a preferred example of the present application, the embedded digital energy network card of the first group of battery cell strings is the host, and when the battery module is in a charging or discharging state, the host can adjust the charging or discharging state of each group of battery cell strings according to the voltage and current information of each group of battery cell strings.

[0072] Specifically, the host centrally manages the working state of each group of battery cell strings based on the voltage and current information of each group of battery cell strings, which can realize overall optimization control of the entire battery module. This design can also reduce the complexity of the battery management system, while improving the stability and efficiency of the system.

[0073] As a preferred example of the present application, the shell is provided with a total + terminal and a total - terminal, the embedded digital energy network card is provided with a battery + terminal, a battery - terminal and a power + terminal, the positive electrode of the battery cell string is electrically connected with the battery + terminal, the negative electrode of the battery cell string is respectively electrically connected with the battery - terminal and the total - terminal, the negative terminals of each group of battery cell strings are electrically connected, and the total + terminal is respectively electrically connected with the power + terminals of each group of battery cell strings.

[0074] Specifically, by electrically connecting the battery + terminal, the battery - terminal and each group of battery cell strings, the number of battery cell strings can be increased or decreased as needed without the need for large-scale modification, which is highly adaptable and facilitates the expansion and customization of the battery module. At the same time, this design rationally integrates multiple terminals, making the electrical layout of the battery module relatively simple, reducing complex wiring and connection, and thus reducing the design complexity of the system.

[0075] As a preferred example of the present application, the embedded digital energy network card includes a drive optocoupler, a power MOS, and a CAN-1, the power MOS includes MOS1 and MOS2, the drain of MOS1 is connected to the positive electrode of the battery string, the source of MOS1 is connected to the source of MOS2, the drain of MOS2 is connected to the power + terminal, and the CAN-1 is used for communication between the embedded digital energy network cards inside the battery module.

[0076] Specifically, MOS1 is used to regulate the current inflow of the battery string, and MOS2 controls the current outflow through the power + terminal. This configuration can effectively realize the charge and discharge switching of the battery string, ensure the stable operation of the system, and provide electrical isolation through the drive optocoupler to improve the safety of the system, ensure that the low-voltage control circuit is not disturbed by the high-voltage circuit, and ensure accurate transmission of the control signal. The introduction of CAN-1 enables efficient communication between the embedded digital energy network cards inside the battery module, ensuring state synchronization between the embedded digital energy network cards, realizing coordinated work of the overall battery system, and helping to improve the operation efficiency and safety of the battery module. This design provides an efficient, safe, and stable battery management system that can effectively improve the charge and discharge control accuracy of the battery module, optimize energy transmission efficiency, improve the scalability and maintainability of the system, and enhance the safety and reliability of the battery management system.

[0077] As a preferred example of the present application, the shell is provided with an RJ45 interface 1 and an RJ45 interface 2, and the embedded digital energy network card 1 includes an RS485-11 / CAN-11, which is electrically connected with the RJ45 interface 1 and the RJ45 interface 2, respectively.

[0078] Specifically, by combining the RS485 / CAN protocol module with the RJ45 interface, the system can realize efficient, flexible, and stable communication. This design not only simplifies wiring and reduces costs, but also enhances the reliability and scalability of the system. Multiple protocol support and standardized interface design make the system compatible and adaptable, meeting the requirements of complex battery management systems and improving the intelligence and remote monitoring capabilities of the system.

[0079] Preferably, the RJ45 interface 1 and the RJ45 interface 2 are also electrically connected with other battery modules or dynamic environment monitoring systems. By connecting multiple devices (such as battery modules and dynamic environment monitoring systems) to the same network through RJ45 interfaces for unified management, wiring and connection methods are simplified. The system can be expanded and connected through existing network cables, reducing the need for dedicated cables and complex wiring. When new battery modules or monitoring devices need to be added, they can be easily connected to the network through the RJ45 interface without the need for large-scale system modifications, making it easy to expand and upgrade the system.

[0080] An equalization method for the lithium ion battery module with equalization capability as described above, comprising the steps of:

[0081] S1: detecting the direction information of the current in the battery module, the voltage and current information of the cell string, and the voltage and current information of the cell, entering S2;

[0082] S2: judging the state of the battery module according to the detected information, when the battery module is in standby state, entering S3, when the battery module is in discharging state, entering S4, when the battery module is in charging state, entering S5;

[0083] S3: executing standby mode, equalizing and adjusting the cell, entering S1;

[0084] S4: executing discharging mode, discharging the battery module, entering S1;

[0085] S5: executing charging mode, charging the battery module, entering S1.

[0086] Specifically, the equalization method can execute different processing strategies according to the state of the battery module, and the dynamic adaptation capability can improve the management accuracy of the battery module, avoid overcharge or overdischarge of the cell string or the cell, and prolong the service life of the battery module.

[0087] Preferably, the temperature value of the cell and whether the circuit is short-circuited can also be detected, if the temperature value of any cell in the battery module exceeds the set temperature value, and / or the current value of the cell string exceeds the set current value, and / or the circuit is short-circuited, the charging or discharging of the battery module is stopped, and the power MOS of the embedded digital energy network card is disconnected.

[0088] As a preferred example of the present application, step S3 comprises:

[0089] S31: detecting the voltage value of each cell in the cell string, setting the voltage value of the cell with the highest voltage as U 高 , and setting the voltage value of the cell with the lowest voltage as U 低 , entering S32;

[0090] S32: detecting and judging whether U 高 > U 设 , if yes, entering S33, if no, entering S1;

[0091] S33: detecting and judging whether U 高 -U 低 > U 差 , if yes, entering S34, if no, entering S1;

[0092] S34: passive equalization is performed on the cell with the highest voltage, when U 高 -U 低 ≤U 差 , enter S31;

[0093] wherein, within any group of cell strings, U 高 is the voltage value of the cell with the highest voltage, U 低 is the voltage value of the cell with the lowest voltage, U 设 is the low voltage setting value of the cell, and U 差 is the set difference between the highest voltage value and the lowest voltage value of the cell.

[0094] Specifically, for each cell in the cell string, this method can dynamically process according to the real-time detected voltage difference, so that each cell will not be overcharged or overdischarged, and the working stability of the entire battery module is improved.

[0095] As a preferred example of the present application, step S4 includes:

[0096] S41: detect and determine whether I 放 ≤(m / n) x I 额放 , if yes, enter S42;

[0097] S42: every interval t, detect the voltage values of the n groups of cell strings, and sort the n groups of cell strings according to the voltage values from high to low, select m groups of cell strings for discharging, cut out the remaining n-m groups of cell strings, and enter S43;

[0098] S43: detect and determine whether there is a cell string in the m groups of cell strings whose voltage value is lower than the set overdischarge value, if yes, enter S44, if no, enter S41;

[0099] S44: cut out the cell string whose voltage value is lower than the set overdischarge value, and enter S45;

[0100] S45: detect and determine whether the number of cut-out cell strings is less than n-m, if yes, enter S41, if no, control the cell strings that have not been cut out to discharge at the same time, and enter S46;

[0101] S46: detect and determine whether there is a cell string in the cell strings participating in discharging whose voltage value is lower than the set overdischarge value, if yes, the battery module stops discharging, if no, enter S41;

[0102] wherein, within the battery module, m is the set value of the number of cell strings simultaneously subjected to dynamic equalization adjustment, n is the total number of cell strings, m 放 is the discharge current value of the battery module, I 额放 is the rated discharge current value of the battery module, and t is the time interval length of detection.

[0103] Specifically, in the discharging process of the battery module, the control method can dynamically adjust the battery cell strings participating in the discharging according to the change of the voltage value of each group of battery cell strings, so that the battery cell strings with relatively high voltage value are discharged first, and the battery cell strings with relatively low voltage value are discharged later. When the voltage value of a group of battery cell strings is lower than the set over-discharge value, it can be cut out in time to avoid over-discharge of the battery cell strings. When the number of battery cell strings with voltage value lower than the set over-discharge value exceeds the set value, the battery module can be controlled to stop discharging. This control method can not only improve the voltage consistency between each group of battery cell strings and the discharging capacity of the battery module, but also avoid over-discharge of the battery cell strings and prolong the service life of the battery module.

[0104] As a preferred example of the present application, step S5 comprises:

[0105] S51: detecting and determining whether I 充 ≤ (m / n) x I 额充 , if yes, entering S52;

[0106] S52: detecting the voltage values of the n groups of battery cell strings every interval t, and sorting the n groups of battery cell strings according to the voltage values from low to high, selecting m groups of battery cell strings for charging, cutting out the remaining n-m groups of battery cell strings, and entering S53;

[0107] S53: detecting and determining whether the voltage value of any battery cell string in the m groups of battery cell strings is higher than the set over-charge value, if yes, entering S54, and if no, entering S51;

[0108] S54: cutting out the battery cell string with voltage value higher than the set over-charge value, and entering S55;

[0109] S55: detecting and determining whether the number of cut-out battery cell strings is less than n-m, if yes, entering S51, and if no, controlling the battery cell strings that have not been cut out to charge simultaneously, and entering S56;

[0110] S56: detecting and determining whether the voltage value of any battery cell string participating in the charging is higher than the set over-charge value, if yes, the battery module stops charging, and if no, entering S51;

[0111] Wherein, in the battery module, m is the set value of the number of battery cell strings simultaneously participating in dynamic equalization adjustment, n is the total number of battery cell strings, m < n, I 放 is the charging current value of the battery module, I 额放 is the rated charging current value of the battery module, and t is the time interval length for detection.

[0112] Specifically, in the charging process of the battery module, the control method can dynamically adjust the battery cell strings participating in the charging according to the change of the voltage value of each group of battery cell strings, so that the battery cell strings with relatively low voltage value are charged first, and the battery cell strings with relatively high voltage value are charged later, when the voltage value of the battery cell strings is higher than the set overcharge value, the battery cell strings can be cut out in time to avoid overcharging, and when the number of battery cell strings with voltage value higher than the set overcharge value exceeds the set value, the battery module can be controlled to stop charging. This control method can not only improve the voltage consistency between each group of battery cell strings, improve the power storage capacity and charging efficiency of the battery module, but also avoid overcharging of the battery cell strings and prolong the service life of the battery module.

[0113] In summary, the lithium ion battery module with equalization capability and the equalization method have the following advantages: 1) when the battery module is discharging or charging, the voltage consistency between each group of battery cell strings can be enhanced to ensure the voltage balance between each group of battery cell strings in parallel direction, and overcharging or overdischarging of the battery cell strings can be avoided to reduce the maintenance cost in later period and prolong the service life of the battery module without energy loss; 2) dynamic processing can be performed according to the real-time detected voltage difference, so that each battery cell in the battery cell string will not be overcharged or overdischarged, and the working stability of the entire battery module is improved; 3) the working state of each group of battery cell strings can be managed centrally to realize overall optimization control of the entire battery module, which reduces the complexity of battery module management and improves the stability and efficiency of the battery module.

[0114] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art, without departing from the spirit and scope of the present application, can make various changes and modifications, therefore the protection scope of the present application should be limited by the scope defined by the claims.

Claims

1. A lithium ion battery module with equalization capability, characterized by, The shell is internally provided with n groups of battery cell groups in parallel connection; The battery cell group includes embedded digital energy network cards and battery cell strings, the battery cell strings are electrically connected with the embedded digital energy network cards, the embedded digital energy network cards can communicate with each other, and the battery cell strings are composed of a plurality of battery cell monomers in series connection; The embedded digital energy network card can collect voltage and current information of the battery cell string, and when the battery module is in a charging or discharging state, the embedded digital energy network card can adjust the charging or discharging state of each group of battery cell strings according to the collected information; The embedded digital energy network card is provided with a voltage sampling circuit, a current sampling circuit, a BTU circuit and a main control chip; the voltage sampling circuit is used for collecting voltage information of the battery cell string and sending the voltage information to the main control chip, the current sampling circuit is used for collecting current information of the battery cell string and sending the current information to the main control chip, the current information includes current value and current direction, the BTU circuit is used for collecting voltage, current and temperature information of the battery cell monomer and sending the information to the main control chip, and the main control chip adjusts the charging or discharging state of each group of battery cell strings according to the voltage and current information of each group of battery cell strings, and can control the BTU circuit to perform equalization adjustment on the battery cell monomer with abnormal voltage according to the voltage and current information of the battery cell monomer; The embedded digital energy network card includes a driving optocoupler, MOS and CAN-1, the MOS includes MOS1 and MOS2, the drain electrode of the MOS1 is connected with the positive electrode of the battery cell string, the source electrode of the MOS1 is connected with the source electrode of the MOS2, the drain electrode of the MOS2 is connected with the power supply + terminal, and the CAN-1 is used for communication between the embedded digital energy network cards in the battery module.

2. The lithium-ion battery module with equalization capability of claim 1, wherein, The embedded digital energy network card of the first group of battery cell groups is a host, and when the battery module is in a charging or discharging state, the host can adjust the charging or discharging state of each group of battery cell strings according to the voltage and current information of each group of battery cell strings.

3. The lithium-ion battery module with equalization capability of claim 1, wherein, The shell is provided with a total + terminal and a total - terminal, the embedded digital energy network card is provided with a battery + terminal, a battery - terminal and a power supply + terminal, the positive electrode of the battery cell string is electrically connected with the battery + terminal, the negative electrode of the battery cell string is respectively electrically connected with the battery - terminal and the total - terminal, the negative electrodes of each group of battery cell strings are electrically connected, and the total + terminal is respectively electrically connected with the power supply + terminals of each group of battery cell strings.

4. The lithium-ion battery module with equalization capability of claim 1, wherein, The shell is provided with an RJ45 interface 1 and an RJ45 interface 2, the embedded digital energy network card includes RS485-11 / CAN-11, and the RS485-11 / CAN-11 is respectively electrically connected with the RJ45 interface 1 and the RJ45 interface 2.

5. A balancing method for the lithium-ion battery module with balancing capability according to any one of claims 1 to 4, characterized in that The method includes the following steps: S1: detecting the direction information of the current in the battery module, the voltage and current information of the battery cell string, and the voltage and current information of the battery cell monomer, and entering S2; S2: judging the state of the battery module according to the detected information, when the battery module is in a standby state, entering S3, when the battery module is in a discharging state, entering S4, and when the battery module is in a charging state, entering S5; S3: executing a standby mode to perform equalization adjustment on the battery cell monomer, and entering S1; S4: performing a discharging mode to discharge the battery module, and entering S1; S5: performing a charging mode to charge the battery module, and entering S1.

6. The equalization method of claim 5, wherein, Step S3 comprises: S31: Detect the voltage value of each battery cell monomer in the battery cell string, and set the voltage value of the battery cell monomer with the highest voltage as U 高 , set the voltage value of the battery cell monomer with the lowest voltage as U 低 , and enter S32; S32: Detect and determine whether U 高 > U 设 If yes, go to S33, if no, go to S1; S33: Detect and determine whether U 高 -U 低 > U 差 , if yes, go to S34, if no, go to S1; S34: passive balancing for the cell monomer with the highest voltage, when U 高 -U 低 ≤U 差 S31; wherein, within any group of cells strings, U 高 is the voltage value of the cell monomer with the highest voltage, U 低 is the voltage value of the cell monomer with the lowest voltage, U 设 is the low voltage set value of the cell monomer, U 差 is the set difference between the highest voltage value and the lowest voltage value of the cell monomer.

7. The equalization method of claim 5, wherein, Step S4 comprises: S41: Detect and determine whether I 放 ≤ (m / n) x I 额放 If yes, go to S42; S42: detecting voltage values of the n groups of battery cell strings every interval t, and sorting the n groups of battery cell strings according to the voltage values from high to low, selecting m groups of battery cell strings to discharge, cutting out the remaining n-m groups of battery cell strings, and entering S43; S43: detecting and judging whether the voltage value of any battery cell string in the m groups of battery cell strings is lower than the set over-discharge value, if yes, entering S44, and if no, entering S41; S44: cutting out the battery cell string with the voltage value lower than the set over-discharge value, and entering S45; S45: detecting and judging whether the number of the cut-out battery cell strings is less than n-m, if yes, entering S41, and if no, controlling the battery cell strings not cut out to discharge simultaneously, and entering S46; S46: detecting and judging whether the voltage value of any battery cell string in the battery cell strings participating in the discharge is lower than the set over-discharge value, if yes, the battery module stops discharging, and if no, entering S41; wherein, in the battery module, m is the number of battery cell strings set value for dynamic equalization adjustment at the same time, n is the total number of battery cell strings value, m < n, I 放 is the discharge current value of the battery module, I 额放 is the rated discharge current value of the battery module, t is the time interval length of detection.

8. The equalization method of claim 5, wherein, Step S5 comprises: S51: Detect and determine whether I 充 ≤ (m / n) x I 额充 If yes, go to S52; S52: detecting voltage values of the n groups of battery cell strings every interval t, and sorting the n groups of battery cell strings according to the voltage values from low to high, selecting m groups of battery cell strings to charge, cutting out the remaining n-m groups of battery cell strings, and entering S53; S53: detecting and judging whether the voltage value of any battery cell string in the m groups of battery cell strings is higher than the set over-charge value, if yes, entering S55, and if no, entering S51; S55: cutting out the battery cell string with the voltage value higher than the set over-charge value, and entering S55; S55: detecting and judging whether the number of the cut-out battery cell strings is less than n-m, if yes, entering S51, and if no, controlling the battery cell strings not cut out to charge simultaneously, and entering S56; S56: detecting and judging whether the voltage value of any battery cell string in the battery cell strings participating in the charge is higher than the set over-charge value, if yes, the battery module stops charging, and if no, entering S51; wherein, in the battery module, m is the number of battery cell strings set value for dynamic equalization adjustment at the same time, n is the total number of battery cell strings value, m < n, I 放 is the charging current value of the battery module, I 额放 is the rated charging current value of the battery module, t is the time interval length of detection.

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