Lithium ion battery module with equalization capability and equalization method

Abstract

The invention provides a lithium ion battery module with equalization capability and an equalization method, the lithium ion battery module comprises a shell, n groups of battery cell group strings are arranged in the shell, and the battery cell group strings are connected in parallel; the battery cell group string comprises embedded digital energy network cards and a battery cell string, the battery cell string is electrically connected with the embedded digital energy network cards, the embedded digital energy network cards can communicate with each other, and the battery cell string is formed by connecting a plurality of battery cells in series; the embedded digital energy network card can collect voltage and current information of the battery cell strings, 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; according to the arrangement, when the battery module is discharged or charged, the working state of each group of battery cell strings can be controlled according to the voltage and current information of the battery cell strings, so that the voltage balance among the battery cell strings in the parallel connection direction is ensured, and the service life of the battery module is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of new energy power technology, and in particular to a lithium-ion battery module with balancing capability and a balancing method. Background Art

[0002] As a high-performance energy storage device, lithium iron phosphate battery packs have been widely used in the communications field, especially in key communications energy storage scenarios such as communication base stations and central computer rooms, due to their advantages such as 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 battery management system (BMS), which work together to ensure the stability and reliability of power supply.

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

[0004] In this context, the traditional way of connecting cells inside battery modules - one parallel and multiple strings (i.e. a parallel group contains multiple series cells) has gradually failed to meet the needs of battery manufacturers and end users. In order to improve the overall performance and flexibility of the battery pack, the combination of two parallel and multiple strings or even multiple parallel and multiple strings of cells has been widely used in battery modules. This design not only improves the energy density and power output capacity of the battery pack, but also enhances the redundancy and reliability of the system.

[0005] However, with the complexity of battery cell combinations, the problem of balancing between battery cells within the battery module has become increasingly prominent, especially in the parallel direction. Since there may be slight performance differences and manufacturing process errors between battery cells, their voltage changes during charging and discharging are inconsistent. This voltage imbalance phenomenon will not only affect the overall performance and life of the battery pack, but may also cause safety problems such as overheating and short circuit.

[0006] The prior art often uses a passive balancing method to balance the cell voltages in a battery module, such as patent CN107516922A. However, this method has a small balancing current, a weak balancing capability, and also causes a waste of power through the balancing resistor.

[0007] Therefore, how to solve the problem of voltage balance between battery strings in the parallel direction when the battery module is discharging or charging has become a key technical problem that needs to be solved urgently in the current design and maintenance of lithium iron phosphate battery packs. Summary of the invention

[0008] In view of this, the present invention aims to provide a lithium-ion battery module with balancing capability and a balancing method to solve the problem in the prior art that the battery module cannot effectively ensure voltage balance between battery strings in the parallel direction when discharging or charging.

[0009] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0010] A lithium-ion battery module with balancing capability comprises a housing, wherein n groups of battery cell strings are arranged in the housing, and the battery cell strings are connected in parallel;

[0011] The battery cell string comprises an embedded digital energy network card and a battery cell string, the battery cell string is electrically connected to the embedded digital energy network card, the embedded digital energy network cards can communicate with each other, and the battery cell string is composed of a plurality of battery cells connected in series;

[0012] The embedded digital energy network card can collect voltage and current information of the battery 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 battery cell strings according to the collected information.

[0013] This setting can enhance the voltage consistency between groups of battery strings when the battery module is discharged or charged, ensure the voltage balance between groups of battery strings in the parallel direction, and avoid overcharging or discharging of the battery strings, thus reducing the subsequent maintenance costs and extending the service life of the battery module without energy loss.

[0014] Furthermore, 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 the voltage information of the battery string and send it to the main control chip. The current sampling circuit is used to collect the current information of the battery string and send it to the main 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 main control chip. 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 balance the battery cells with abnormal voltage according to the voltage and current information of the battery cells.

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

[0016] Furthermore, the embedded digital energy network card of the first group of battery cell strings is the host. 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.

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

[0018] Furthermore, 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 to the battery + terminal, the negative electrode of the battery cell string is electrically connected to the battery - terminal and the total - terminal respectively, the negative terminals of each group of battery cell strings are electrically connected, and the total + terminal is electrically connected to the power + terminal of each group of battery cell strings respectively.

[0019] By electrically connecting the battery + terminal, 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 modifications. It has strong adaptability and facilitates the expansion and customization of battery modules.

[0020] Furthermore, the embedded digital energy network card includes a driving optocoupler, a power MOS and CAN-1, the power MOS includes MOS1 and MOS2, the drain of the 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 supply + 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 accuracy of the battery module, optimize the energy transmission efficiency, improve the scalability and maintainability of the system, and enhance the safety and reliability of the battery management system.

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

[0023] This design not only simplifies wiring and reduces costs, but also enhances the reliability and scalability of the system. The support for multiple protocols and standardized interface design make the system highly compatible and adaptable, able to meet the requirements of complex battery management systems and enhance the system's intelligence and remote monitoring capabilities.

[0024] A balancing method, used for the aforementioned lithium-ion battery module with balancing capability, comprises the steps of:

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

[0026] S2: Determine the state of the battery module according to the detected information. When the battery module is in standby state, enter S3. When the battery module is in discharge state, enter S4. When the battery module is in charge state, enter S5.

[0027] S3: Execute standby mode, balance and adjust the battery cells, and enter S1;

[0028] S4: Execute the discharge mode to discharge the battery module and enter S1;

[0029] S5: Execute the charging mode, charge the battery module, and enter S1.

[0030] This balancing method can execute different processing strategies according to the status of the battery module. This dynamic adaptability can improve the management accuracy of the battery module, avoid overcharging or over-discharging of the battery string or battery cell, and thus extend the service life of the battery module.

[0031] Further, step S3 includes:

[0032] S31: Detect the voltage value of each cell in the cell string, and set the voltage value of the cell with the highest voltage as U 高 , set the voltage value of the cell with the lowest voltage to U 低 , enter S32;

[0033] S32: Detect and determine whether U 高 >U 设 If yes, go to S33, if no, go to S1;

[0034] S33: Detect and determine whether U 高 -U 低 >U 差 If yes, go to S34, if no, go to S1;

[0035] S34: Passively balance the cell with the highest voltage. 高 -U 低 ≤U 差 When , enter S31;

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

[0037] This method can dynamically process the voltage differences detected in real time, so that each battery cell will not be overcharged or over-discharged, thereby improving the operating stability of the entire battery module.

[0038] Further, step S4 includes:

[0039] S41: Detect and determine whether I 放 ≤(m / n)×I 额放 , if yes, go to S42;

[0040] S42: every time interval t, detect the voltage values ​​of n groups of battery strings, and sort the n groups of battery strings according to the voltage values, select m groups of battery strings from high to low for discharge, and cut out the remaining nm groups of battery strings, and enter S43;

[0041] S43: Detect and determine whether the voltage value of a cell string in the m groups of cell strings is lower than the set over-discharge value. If so, proceed to S44; if not, proceed to S41;

[0042] S44: Cut out the battery cell string whose voltage value is lower than the set over-discharge value, and enter S45;

[0043] S45: Detect and determine whether the number of cell strings cut out is less than nm, if so, proceed to S41, if not, control the cell strings that have not been cut out to discharge simultaneously, proceed to S46;

[0044] S46: Detect and determine whether the voltage value of a cell string among the cell strings involved in the discharge is lower than the set over-discharge value. If so, the battery module stops discharging. If not, enter S41.

[0045] In the battery module, m is the set value of the number of battery strings that are dynamically balanced and adjusted at the same time, n is the total number of battery 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 detection time interval.

[0046] This control method can not only improve the voltage consistency between groups of battery cell strings and improve the discharge capacity of the battery module, but also avoid excessive discharge of the battery cell strings and extend the service life of the battery module.

[0047] Further, step S5 includes:

[0048] S51: Detect and determine whether I 充 ≤(m / n)×I 额充 , if yes, go to S52;

[0049] S52: every time interval t, detect the voltage values ​​of n groups of battery strings, and sort the n groups of battery strings according to the voltage values, select m groups of battery strings from low to high for charging, and cut out the remaining nm groups of battery strings, and enter S53;

[0050] S53: Detect and determine whether the voltage value of a cell string in the m groups of cell strings is higher than the set overcharge value. If so, proceed to S54; if not, proceed to S51;

[0051] S54: Cut out the battery cell string whose voltage value is higher than the set overcharge value, and enter S55;

[0052] S55: Detect and determine whether the number of cell strings cut out is less than nm, if so, proceed to S51, if not, control the cell strings that have not been cut out to be charged simultaneously, proceed to S56;

[0053] S56: Detect and determine whether the voltage value of a cell string among the cell strings involved in charging is higher than the set overcharge value. If so, the battery module stops charging. If not, enter S51;

[0054] In the battery module, m is the set value of the number of battery strings that are dynamically balanced and adjusted at the same time, 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 detection time interval.

[0055] This control method can not only improve the voltage consistency between groups of battery cell strings, improve the battery module's storage capacity and charging efficiency, but also avoid overcharging of the battery cell strings and extend 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 described in the present invention have the following advantages:

[0057] 1) When the battery module is discharged or charged, it can not only enhance the voltage consistency between the groups of battery strings, ensure the voltage balance between the groups of battery strings in the parallel direction, but also avoid overcharging or discharging of the battery strings, reduce the subsequent maintenance costs, and extend the service life of the battery module without energy loss;

[0058] 2) It can dynamically process the voltage difference detected in real time, so that each cell in the cell string will not be overcharged or over-discharged, thus improving the working stability of the entire battery module;

[0059] 3) Centralized management of the working status of each group of battery strings can achieve overall optimization control of the entire battery module, reduce the complexity of battery module management, and improve the stability and efficiency of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a schematic diagram of the structure of a lithium-ion battery module according to an embodiment of the present invention;

[0061] Figure 2It is a schematic diagram of the structure of the embedded digital energy network card described in an embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Example 1

[0063] like Figure 1-2 As shown, a lithium-ion battery module with balancing capability includes a housing, wherein n groups of battery cell strings are arranged in the housing, and the battery cell strings are connected in parallel;

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

[0065] The embedded digital energy network card can collect voltage and current information of the battery 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 battery cell strings according to the collected information.

[0066] Specifically, the embedded digital energy network card can detect the voltage of each group of battery cell strings in real time and dynamically adjust the charging and discharging status of the battery cell strings. When the battery module is in a discharging state, the battery cell strings with relatively high voltage values ​​can be discharged first, and the battery cell strings with relatively low voltage values ​​can be discharged later. When the battery module is in a charging state, the battery cell strings with relatively low voltage values ​​can be charged first, and the battery cell strings with relatively high voltage values ​​can be charged later. This setting can not only enhance the voltage consistency between the groups of battery cell strings and ensure the voltage balance between the groups of battery cell strings in the parallel direction when the battery module is discharged or charged, but also avoid overcharging or discharging of the battery cell strings, reduce the later maintenance costs, and extend the service life of the battery module without energy loss.

[0067] Preferably, the battery cell string consists of 20 battery cells connected in series.

[0068] Preferably, the structures of the embedded digital energy network cards are 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 main control chip. The voltage sampling circuit is used to collect the voltage information of the battery string and send it to the main control chip. The current sampling circuit is used to collect the current information of the battery string and send it to the main 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 main control chip. 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 balance the battery cells with abnormal voltage according to the voltage and current information of the battery cells.

[0070] Specifically, the main control chip adjusts the charging or discharging status of each group of battery strings according to the voltage and current information of each group of battery strings, which can ensure the voltage consistency of the battery strings during the charging or discharging process, and the BTU circuit can passively balance the cells with high voltage in the battery string to prevent overcharging or over-discharging of individual cells. This setting can reduce the performance degradation of the battery module and extend 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. 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 status of each group of battery strings based on the voltage and current information of each group of battery strings, which can achieve 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 pole of the battery cell string is electrically connected to the battery + terminal, the negative pole of the battery cell string is electrically connected to the battery - terminal and the total - terminal respectively, the negative terminals of each group of battery cell strings are electrically connected, and the total + terminal is electrically connected to the power + terminal of each group of battery cell strings respectively.

[0074] Specifically, by electrically connecting the battery + terminal and the battery - terminal to each group of battery cell strings, the number of battery cell strings can be increased or decreased as needed without large-scale modifications. It has strong adaptability and is convenient for expansion and customization of battery modules. At the same time, this design reasonably integrates multiple terminals electrically, making the electrical layout of the battery module relatively simple, reducing complex wiring and connections, 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 driving optocoupler, a power MOS and CAN-1, the power MOS includes MOS1 and MOS2, the drain of the MOS1 is connected to the positive electrode of the battery cell string, the source of MOS1 is connected to the source of MOS2, the drain of MOS2 is connected to the power supply + terminal, and the CAN-1 is used for communication between embedded digital energy network cards inside the battery module.

[0076] Specifically, MOS1 is used to regulate the current inflow of the battery string, while MOS2 controls the current outflow through the power + terminal. This configuration can effectively realize the charging and discharging switching of the battery string and ensure the stable operation of the system. The driving optocoupler can provide electrical isolation, improve the safety of the system, ensure that the low-voltage control circuit is not interfered by the high-voltage circuit, and ensure the 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, ensures the state synchronization between each embedded digital energy network card, realizes the coordinated work of the overall battery system, and helps to improve the operating efficiency and safety of the battery module. The design provides an efficient, safe and stable battery management system, which can effectively improve the charging and discharging control accuracy of the battery module, optimize the 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 RS485-11 / CAN-11, and the RS485-11 / CAN-11 is electrically connected to 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 achieve 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 highly compatible and adaptable, which can meet the requirements of complex battery management systems and enhance the intelligence and remote monitoring capabilities of the system.

[0079] Preferably, the RJ45 interface 1 and the RJ45 interface 2 are also electrically connected to other battery modules or dynamic environment monitoring systems. By connecting multiple devices (such as battery modules, dynamic environment monitoring systems, etc.) to the same network and managing them uniformly through the RJ45 interface, the 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 equipment need to be added, the new equipment only needs to be connected to the network through the RJ45 interface. There is no need to make large-scale changes to the system, and the system can be easily expanded and upgraded.

[0080] A balancing method, used for the aforementioned lithium-ion battery module with balancing capability, comprises the steps of:

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

[0082] S2: Determine the state of the battery module according to the detected information. When the battery module is in standby state, enter S3. When the battery module is in discharge state, enter S4. When the battery module is in charge state, enter S5.

[0083] S3: Execute standby mode, balance and adjust the battery cells, and enter S1;

[0084] S4: Execute the discharge mode to discharge the battery module and enter S1;

[0085] S5: Execute the charging mode, charge the battery module, and enter S1.

[0086] Specifically, this balancing method can execute different processing strategies according to the state of the battery module. This dynamic adaptation capability can improve the management accuracy of the battery module, avoid overcharging or over-discharging of the battery string or battery cell, and thus extend the service life of the battery module.

[0087] Preferably, the temperature value of the battery cell and whether a short circuit occurs in the circuit can also be detected. If the temperature value of any battery cell in the battery module exceeds the set temperature value, and / or the current value of the battery cell string exceeds the set current value, and / or a short circuit occurs in the circuit, charging or discharging 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 includes:

[0089] S31: Detect the voltage value of each cell in the cell string, and set the voltage value of the cell with the highest voltage as U 高 , set the voltage value of the cell with the lowest voltage to U 低 , enter S32;

[0090] S32: Detect and determine whether U 高 >U 设 If yes, go to S33, if no, go to S1;

[0091] S33: Detect and determine whether U 高 -U 低 >U 差 If yes, go to S34, if no, go to S1;

[0092] S34: Passively balance the cell with the highest voltage. 高 -U 低 ≤U 差 When , enter S31;

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

[0094] Specifically, for each battery cell in the battery string, this method can perform dynamic processing based on the voltage difference detected in real time, so that each battery cell will not be overcharged or over-discharged, thereby improving the working stability of the entire battery module.

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

[0096] S41: Detect and determine whether I 放 ≤(m / n)×I 额放 , if yes, go to S42;

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

[0098] S43: Detect and determine whether the voltage value of a cell string in the m groups of cell strings is lower than the set over-discharge value. If so, proceed to S44; if not, proceed to S41;

[0099] S44: Cut out the battery cell string whose voltage value is lower than the set over-discharge value, and enter S45;

[0100] S45: Detect and determine whether the number of cell strings cut out is less than nm, if so, proceed to S41, if not, control the cell strings that have not been cut out to discharge simultaneously, proceed to S46;

[0101] S46: Detect and determine whether the voltage value of a cell string among the cell strings involved in the discharge is lower than the set over-discharge value. If so, the battery module stops discharging. If not, enter S41.

[0102] In the battery module, m is the set value of the number of battery strings that are dynamically balanced and adjusted at the same time, n is the total number of battery 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 detection time interval.

[0103] Specifically, during the discharge process of the battery module, this control method can dynamically adjust the battery cell strings involved in the discharge as the voltage values ​​of each group of battery cell strings change, so that the battery cell strings with relatively higher voltage values ​​are discharged first, and the battery cell strings with relatively lower voltage values ​​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 excessive discharge of the battery cell strings, and when the number of battery cell strings with voltage values ​​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 groups of battery cell strings and improve the discharge capacity of the battery module, but also avoid excessive discharge of the battery cell strings and extend the service life of the battery module.

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

[0105] S51: Detect and determine whether I 充 ≤(m / n)×I 额充 , if yes, go to S52;

[0106] S52: every time interval t, detect the voltage values ​​of n groups of battery strings, and sort the n groups of battery strings according to the voltage values, select m groups of battery strings from low to high for charging, and cut out the remaining nm groups of battery strings, and enter S53;

[0107] S53: Detect and determine whether the voltage value of a cell string in the m groups of cell strings is higher than the set overcharge value. If so, proceed to S54; if not, proceed to S51;

[0108] S54: Cut out the battery cell string whose voltage value is higher than the set overcharge value, and enter S55;

[0109] S55: Detect and determine whether the number of cell strings cut out is less than nm, if so, proceed to S51, if not, control the cell strings that have not been cut out to be charged simultaneously, proceed to S56;

[0110] S56: Detect and determine whether the voltage value of a cell string among the cell strings involved in charging is higher than the set overcharge value. If so, the battery module stops charging. If not, enter S51;

[0111] In the battery module, m is the set value of the number of battery strings that are dynamically balanced and adjusted at the same time, 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 detection time interval.

[0112] Specifically, during the charging process of the battery module, this control method can dynamically adjust the battery cell strings involved in the charging as the voltage values ​​of each group of battery cell strings change, so that the battery cell strings with relatively low voltage values ​​are charged first, and the battery cell strings with relatively high voltage values ​​are charged later. When the voltage value of a group of battery cell strings is higher than the set overcharge value, it can be cut out in time to avoid overcharging of the battery cell strings, and when the number of battery cell strings with voltage values ​​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 groups 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 extend the service life of the battery module.

[0113] In summary, the lithium-ion battery module with balancing capability and the balancing method described in the present application have the following advantages: 1) When the battery module is discharged or charged, it can not only enhance the voltage consistency between each group of battery cell strings and ensure the voltage balance between each group of battery cell strings in the parallel direction, but also avoid overcharging or discharging of the battery cell strings, reduce the subsequent maintenance costs, and extend the service life of the battery module without energy loss; 2) It can dynamically process the voltage difference detected in real time, so that each battery cell in the battery cell string will not be overcharged or over-discharged, thereby improving the working stability of the entire battery module; 3) Centralized management of the working status of each group of battery cell strings can achieve overall optimization control of the entire battery module, reduce the complexity of battery module management, and improve the stability and efficiency of the battery module.

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

Claims

1. A lithium-ion battery module with balancing capability, characterized in that: It comprises a shell, in which n groups of battery cell strings are arranged, and the battery cell strings are connected in parallel; The battery cell string comprises an embedded digital energy network card and a battery cell string, the battery cell string is electrically connected to the embedded digital energy network card, the embedded digital energy network cards can communicate with each other, and the battery cell string is composed of a plurality of battery cells connected in series; The embedded digital energy network card can collect voltage and current information of the battery 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 battery cell strings according to the collected information.

2. The lithium-ion battery module with balancing capability according to claim 1, characterized in that: 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 the voltage information of the battery string and send it to the main control chip. The current sampling circuit is used to collect the current information of the battery string and send it to the main 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 main control chip. 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 balance the battery cells with abnormal voltage according to the voltage and current information of the battery cells.

3. The lithium-ion battery module with balancing capability according to claim 1, characterized in that: The embedded digital energy network card of the first group of battery cell strings is the host. When the battery module is in the 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.

4. The lithium-ion battery module with balancing capability according to claim 1, characterized in that: 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 to the battery + terminal, the negative electrode of the battery cell string is electrically connected to the battery - terminal and the total - terminal respectively, the negative terminal of each group of battery cell strings is electrically connected, and the total + terminal is electrically connected to the power + terminal of each group of battery cell strings respectively.

5. The lithium-ion battery module with balancing capability according to claim 4, characterized in that: The embedded digital energy network card includes a driving optical coupler, a power MOS and a CAN-1. The power MOS includes MOS1 and MOS2. The drain of the MOS1 is connected to the positive electrode of the battery string, the source of the MOS1 is connected to the source of the MOS2, and the drain of the MOS2 is connected to the power supply + terminal. The CAN-1 is used for communication between the embedded digital energy network cards inside the battery module.

6. The lithium-ion battery module with balancing capability according to claim 1, characterized in that: The housing is provided with an RJ45 interface 1 and an RJ45 interface 2, and the embedded digital energy network card 1 includes RS485-11 / CAN-11, and the RS485-11 / CAN-11 is electrically connected to the RJ45 interface 1 and the RJ45 interface 2 respectively.

7. A balancing method, used for the lithium-ion battery module with balancing capability as claimed in any one of claims 1 to 6, characterized in that: Includes steps: S1: Detect the direction information of the current in the battery module, the voltage and current information of the battery string, and the voltage and current information of the battery cell, and enter S2; S2: Determine the state of the battery module according to the detected information. When the battery module is in standby state, enter S3. When the battery module is in discharge state, enter S4. When the battery module is in charge state, enter S5. S3: Execute standby mode, balance and adjust the battery cells, and enter S1; S4: Execute the discharge mode to discharge the battery module and enter S1; S5: Execute the charging mode, charge the battery module, and enter S1.

8. The equalization method according to claim 7, characterized in that: Step S3 includes: S31: Detect the voltage value of each cell in the cell string, and set the voltage value of the cell with the highest voltage as U 高 , set the voltage value of the cell with the lowest voltage to U 低 , 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: Passively balance the cell with the highest voltage. 高 -U 低 ≤U 差 When , enter S31; Among them, in any group of battery strings, U 高 is the voltage value of the cell with the highest voltage, U 低 is the voltage value of the battery cell with the lowest voltage, U 设 is the low voltage setting value of the battery cell, U 差 It is the set difference between the highest voltage value and the lowest voltage value of the battery cell.

9. The equalization method according to claim 7, characterized in that: Step S4 includes: S41: Detect and determine whether I 放 ≤(m / n)×I 额放 , if yes, go to S42; S42: every time interval t, detect the voltage values ​​of n groups of battery strings, and sort the n groups of battery strings according to the voltage values, select m groups of battery strings from high to low for discharge, and cut out the remaining nm groups of battery strings, and enter S43; S43: Detect and determine whether the voltage value of a cell string in the m groups of cell strings is lower than the set over-discharge value. If so, proceed to S44; if not, proceed to S41; S44: Cut out the battery cell string whose voltage value is lower than the set over-discharge value, and enter S45; S45: Detect and determine whether the number of cell strings cut out is less than nm, if so, proceed to S41, if not, control the cell strings that have not been cut out to discharge simultaneously, proceed to S46; S46: Detect and determine whether the voltage value of a cell string among the cell strings involved in the discharge is lower than the set over-discharge value. If so, the battery module stops discharging. If not, enter S41. In the battery module, m is the set value of the number of battery strings that are dynamically balanced and adjusted at the same time, n is the total number of battery 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 detection time interval.

10. The equalization method according to claim 7, characterized in that: Step S5 includes: S51: Detect and determine whether I 充 ≤(m / n)×I 额充 , if yes, go to S52; S52: every time interval t, detect the voltage values ​​of n groups of battery strings, and sort the n groups of battery strings according to the voltage values, select m groups of battery strings from low to high for charging, and cut out the remaining nm groups of battery strings, and enter S53; S53: Detect and determine whether the voltage value of a cell string in the m groups of cell strings is higher than the set overcharge value. If so, proceed to S54; if not, proceed to S51; S54: Cut out the battery cell string whose voltage value is higher than the set overcharge value, and enter S55; S55: Detect and determine whether the number of cell strings cut out is less than nm, if so, proceed to S51, if not, control the cell strings that have not been cut out to be charged simultaneously, proceed to S56; S56: Detect and determine whether the voltage value of a cell string among the cell strings involved in charging is higher than the set overcharge value. If so, the battery module stops charging. If not, enter S51; In the battery module, m is the set value of the number of battery strings that are dynamically balanced and adjusted at the same time, 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 detection time interval.

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