CN117767483B - Battery cell balance management method and system - Google Patents

Battery cell balance management method and system Download PDF

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CN117767483B
CN117767483B CN202311796156.0A CN202311796156A CN117767483B CN 117767483 B CN117767483 B CN 117767483B CN 202311796156 A CN202311796156 A CN 202311796156A CN 117767483 B CN117767483 B CN 117767483B
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battery
cell
voltage
cells
adjacent
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CN117767483A (en
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赖良海
岳应军
王宪强
周贤军
徐小飞
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Shenzhen E-Tek Electronics Manufactory Ltd
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Shenzhen E-Tek Electronics Manufactory Ltd
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Abstract

The application provides a battery cell balance management method and a system, which relate to battery technology and comprise the following steps: the method comprises the steps of obtaining the voltage of each cell in a battery, calculating the voltage difference between adjacent cells according to the obtained voltage of each cell, calculating the self-adaptive voltage difference threshold of the battery according to the capacity attenuation of the battery, the temperature change of the battery and the preset basic voltage difference between each cell, judging the abnormal cells in the two adjacent cells when the voltage difference between the two adjacent cells is larger than the self-adaptive voltage difference threshold, carrying out multistage balance management on the abnormal cells, enhancing the safety of a battery system, prolonging the service life of the battery system and improving the overall performance.

Description

Battery cell balance management method and system
Technical Field
The present application relates to the field of battery technologies, and in particular, to a method and a system for balancing and managing battery cells.
Background
In battery packs, cell balancing is a key technique that involves controlling the charge and discharge process between cells to ensure electrical charge balance between the individual cells. This is critical to the performance, life and safety of the battery. When the battery cells in the storage battery pack have unbalanced electric quantity, some battery cells may be overcharged, and other battery cells may be in an overdischarged state. Such an imbalance in power can result in wasted energy because an overcharged cell cannot effectively store more energy, while an overdriven cell can result in a reduced capacity. In addition, the overcharging and overdischarging conditions of the battery cells can negatively impact the overall performance and life of the battery pack. Overcharging the battery cell may lead to uncontrolled chemical reactions inside the battery cell, generating gas and heat, causing safety risks, and even possibly causing serious accidents such as short circuits, explosions, fires, etc. of the battery pack. And the overdischarge of the battery core can lead to the capacity loss and the service life shortening of the battery core, and the available energy and the service time of the storage battery are reduced.
Therefore, it plays a vital role in the battery pack by implementing the cell balancing technique.
Disclosure of Invention
The invention provides a battery cell balance management method and system, which are used for balancing cells and prolonging the service life of a battery.
In a first aspect, a method for balancing and managing battery cells is provided. The method comprises the following steps:
acquiring the voltage of each cell in the battery, and calculating the voltage difference between adjacent cells according to the acquired voltage of each cell;
Calculating an adaptive voltage difference threshold of the battery according to capacity attenuation of the battery, temperature change of the battery and preset basic voltage difference between each battery cell;
When the voltage difference between two adjacent cells is larger than the self-adaptive voltage difference threshold value, judging abnormal cells in the two adjacent cells;
and carrying out multistage balance management on the abnormal battery cells.
In one possible design, the adaptive voltage difference threshold of the battery is calculated based on the capacity fade of the battery, the temperature change of the battery, and the preset base voltage difference between each cell, including,
Calculating a capacity fading factor of the battery according to the current capacity of the battery and the capacity of a preset new battery;
acquiring a temperature change factor of the battery according to the temperature change of the battery and a preset temperature factor table;
and calculating the product of the preset basic voltage difference between each cell and the capacity attenuation factor and the temperature change factor of the battery to obtain the self-adaptive voltage difference threshold of the battery.
In one possible design, when the voltage difference between two adjacent cells is greater than the adaptive voltage difference threshold, an abnormal cell in the two adjacent cells is identified, including,
Calculating average cell voltage according to the obtained voltage of each cell;
and judging abnormal cells in the two adjacent cells according to the average cell voltage.
Optionally, the abnormal cell in the two adjacent cells is discriminated according to the average cell voltage, including,
When the difference between the high-voltage cell and the average cell voltage in the two adjacent cells is smaller than the difference between the low-voltage cell and the average cell voltage in the two adjacent cells, judging that the high-voltage cell in the two adjacent cells is an abnormal cell;
And when the difference between the high-voltage cell and the average cell voltage in the two adjacent cells is larger than the difference between the low-voltage cell and the average cell voltage in the two adjacent cells, judging that the low-voltage cell in the two adjacent cells is an abnormal cell.
In one possible design, the abnormal cells are managed in a multi-level balanced manner, including,
Performing primary balance management on the abnormal battery cells;
After the primary balance management, judging whether the two adjacent battery cells are still in an abnormal state or not again;
And when the voltage difference between two adjacent cells is still larger than the self-adaptive voltage difference threshold value, performing secondary balance management on the abnormal cells.
Alternatively, a level of balancing management, including,
When the abnormal battery cell is a battery cell with high voltage in two adjacent battery cells, connecting the battery cell with high voltage in the two adjacent battery cells with a preset first resistor;
When the abnormal battery cell is a battery cell with low voltage in the two adjacent battery cells, a control switch between a battery cell with high voltage in the two adjacent battery cells and a battery cell with low voltage in the two adjacent battery cells is opened, and charges in the battery cell with high voltage in the two adjacent battery cells are transferred to the battery cell with low voltage in the two adjacent battery cells through the control switch.
Optionally, a secondary balance management, including,
When the abnormal battery cell is a battery cell with high voltage in the two adjacent battery cells, the battery cell with high voltage in the two adjacent battery cells is connected with a preset second resistor;
When the abnormal battery cell is a battery cell with low voltage in the two adjacent battery cells, an energy transfer circuit between a battery cell with high voltage in the two adjacent battery cells and a battery cell with low voltage in the two adjacent battery cells is opened, and charges in the battery cell with high voltage in the two adjacent battery cells are transferred to the battery cell with low voltage in the two adjacent battery cells through the energy transfer circuit;
the preset second resistance value is larger than the preset first resistance value.
Optionally, characterized in that,
After primary balance management, the voltage difference between two adjacent cells is reduced to be within a self-adaptive voltage difference threshold value, a cell with high voltage in the two adjacent cells is disconnected with a preset first resistor, or a control switch between the cell with high voltage in the two adjacent cells and the cell with low voltage in the two adjacent cells is closed, so that the initial connection state between the two adjacent cells is restored;
after the secondary balance management, the voltage difference between two adjacent cells is reduced to be within the self-adaptive voltage difference threshold value, and the current connection state between the two adjacent cells is maintained;
after the secondary balance management, the voltage difference between two adjacent battery cells is still larger than the self-adaptive voltage difference threshold value, and the power supply of the battery is cut off.
In one possible design, the voltage of each cell in the battery is obtained, and the voltage difference between adjacent cells is calculated according to the obtained voltage of each cell, including,
The voltage of each cell in the battery was cyclically measured every 3 hours.
In a second aspect, a battery cell balance management system is provided. The system comprises:
The acquisition module is used for acquiring the voltage of each cell in the battery and calculating the voltage difference between the adjacent cells according to the acquired voltage of each cell;
The calculation module is used for calculating an adaptive voltage difference threshold value of the battery according to capacity attenuation of the battery, temperature change of the battery and preset basic voltage difference between each battery core;
the judging module is used for judging abnormal cells in the two adjacent cells when the voltage difference between the two adjacent cells is larger than the self-adaptive voltage difference threshold value;
and the balance management module is used for carrying out multistage balance management on the abnormal battery cells.
The invention provides a battery cell balance management method and a system, wherein the method comprises the following steps: the method comprises the steps of obtaining the voltage of each cell in a battery, calculating the voltage difference between adjacent cells according to the obtained voltage of each cell, calculating the self-adaptive voltage difference threshold of the battery according to the capacity attenuation of the battery, the temperature change of the battery and the preset basic voltage difference between each cell, judging the abnormal cells in the two adjacent cells when the voltage difference between the two adjacent cells is larger than the self-adaptive voltage difference threshold, and carrying out multistage balance management on the abnormal cells. That is, by acquiring the voltage of each cell and calculating the voltage difference between adjacent cells, the state of the battery system can be monitored; the self-adaptive voltage difference threshold is calculated according to the capacity attenuation, the temperature change and the preset basic voltage difference of the battery, the threshold can be dynamically adjusted according to actual conditions, the change of the battery system under different working conditions is adapted, and the stability of the system is improved; when the voltage difference between two adjacent cells is larger than the self-adaptive voltage difference threshold, abnormal cells in the two adjacent cells can be timely distinguished, unbalance among the cells is reduced, and the risk of overcharging or overdischarging of the cells is reduced, so that the service life of a battery system is prolonged; the abnormal cells are subjected to multistage balance management, so that the voltage between the cells can be kept within a reasonable range, the balance state between the cells is better controlled, and the stability of the system is further enhanced.
It should be understood that the description in this summary is not intended to limit the critical or essential features of the embodiments of the invention, nor is it intended to limit the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
The above and other features, advantages and aspects of embodiments of the present invention will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements.
FIG. 1 is a flow chart of a method for managing cell balance of a battery according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a battery cell imbalance structure according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an energy transfer circuit according to an embodiment of the present invention;
FIG. 4 is a flow chart of a multi-level balancing management of an embodiment of the present invention;
Fig. 5 is a schematic structural diagram of a battery cell balance management system according to an embodiment of the present invention.
Detailed Description
In order to enable a person skilled in the art to better understand the technical solutions in one or more embodiments of the present specification, the technical solutions in one or more embodiments of the present specification will be clearly and completely described below with reference to the drawings in one or more embodiments of the present specification, and it is obvious that the described embodiments are only some embodiments of the present specification, not all embodiments. All other embodiments, which can be made by one or more embodiments of the present disclosure without inventive faculty, are intended to be within the scope of the present disclosure.
It should be noted that, the description of the embodiment of the present invention is only for the purpose of more clearly describing the technical solution of the embodiment of the present invention, and does not constitute a limitation on the technical solution provided by the embodiment of the present invention.
An embodiment of the invention provides a battery cell balance management method, and fig. 1 is a flowchart of the battery cell balance management method according to the embodiment of the invention. Referring to fig. 1, the method includes:
S101, acquiring the voltage of each cell in the battery, and calculating the voltage difference between adjacent cells according to the acquired voltage of each cell.
The voltage difference can be obtained by calculating the difference between adjacent cells by using the obtained voltage value of each cell. For example, for the voltage difference between adjacent cells Vi and vi+1, Δv= |vi+1-vi| may be used for calculation, v1=3.7v, v2=3.6v, and the voltage difference between V1 and V2 is 0.1V.
In this embodiment, by calculating the voltage difference between the adjacent cells, it is possible to detect whether an abnormal or faulty cell exists in the battery, and if the voltage difference between the two adjacent cells is significantly greater than the threshold, an abnormal cell exists therein, and further balance management is required for the abnormal cell.
Optionally, the voltage of each cell in the battery is obtained, and the voltage difference between adjacent cells is calculated according to the obtained voltage of each cell, including,
The voltage of each cell in the battery was cyclically measured every 3 hours.
In this embodiment, by periodically and circularly detecting the voltage of the battery cell, state information of the battery cell in the battery can be obtained in time, and abnormal or fault of the battery cell voltage can be found, so that corresponding measures can be taken, and the safety of the battery can be enhanced.
S102, calculating an adaptive voltage difference threshold of the battery according to capacity fading of the battery, temperature change of the battery and preset basic voltage difference between each battery core.
In this embodiment, by considering the capacity attenuation of the battery, the temperature change of the battery and the basic voltage difference between each cell, the adaptive voltage difference threshold of the battery is calculated, so that the method is closer to the actual use condition of the battery, the accuracy and reliability of cell balance detection are improved, and the safety, reliability and performance of the battery pack are improved.
Optionally, an adaptive voltage difference threshold for the battery is calculated based on the capacity fade of the battery, the temperature change of the battery, and a preset base voltage difference between each cell, including,
Calculating a capacity fading factor of the battery according to the current capacity of the battery and the capacity of a preset new battery;
acquiring a temperature change factor of the battery according to the temperature change of the battery and a preset temperature factor table;
and calculating the product of the preset basic voltage difference between each cell and the capacity attenuation factor and the temperature change factor of the battery to obtain the self-adaptive voltage difference threshold of the battery.
In this embodiment, the calculation formula for calculating the capacity reduction factor of the battery according to the current capacity of the battery and the capacity of the preset new battery may be that the capacity reduction factor=the current capacity/the preset battery capacity, for example, the preset battery capacity is 1000mAh, and the current capacity of the battery is 800mAh, and the capacity reduction factor is 800mAh/1000 mah=0.8. The preset battery capacity is full capacity of the new battery when the new battery is initially used.
In this embodiment, the preset temperature factor table is a corresponding preset table between the battery temperature and the temperature change factor, and the corresponding value can be adjusted according to the actual situation. For example, when the battery temperature is 25 ℃, the temperature change factor of the battery is 1, and when the battery temperature is 50 ℃, the temperature change factor of the battery is 1.2. The following table is an example of a temperature factor table, as shown in the following table:
Battery temperature (. Degree. C.) Temperature change factor
25 1
50 1.2
70 1.5
... ...
After the capacity attenuation factor of the battery and the temperature change factor of the battery are obtained, the adaptive voltage difference threshold of the battery can be calculated by the product of the preset basic voltage difference between each electric core and the capacity attenuation factor of the battery and the temperature change factor of the battery, namely, the adaptive voltage difference threshold=the preset basic voltage difference×the capacity attenuation factor×the temperature change factor. For example, the preset basic voltage difference between each cell is 0.2V, the capacity fading factor of the battery is 0.8, and the temperature variation factor of the battery is 1.2, and the adaptive voltage difference threshold of the battery is 0.2v×0.8× 1.2=0.192V according to the calculation, and the adaptive voltage difference threshold is 0.192V according to the preset basic voltage difference, capacity fading factor and temperature variation factor.
In this embodiment, the adaptive voltage difference threshold of the battery is calculated by the product of the preset basic voltage difference between each battery cell and the capacity attenuation factor and the temperature change factor of the battery, so that the influence of various external factors on the voltage difference between the battery cells in the battery is considered, the adaptive voltage difference threshold calculation is realized, the voltage difference monitoring and abnormal discrimination of the battery cells under different conditions can be adapted, and the reliability is improved.
S103, when the voltage difference between the two adjacent cells is larger than the self-adaptive voltage difference threshold value, judging the abnormal cell in the two adjacent cells.
In this embodiment, by detecting and discriminating the abnormal battery cell in time, corresponding measures can be taken in time to ensure the safety of the battery system, avoid the decrease of the overall performance of the battery system, prolong the service life of the battery, and improve the reliability and usability of the battery system.
Optionally, when the voltage difference between two adjacent cells is greater than the adaptive voltage difference threshold, discriminating between abnormal cells in the two adjacent cells, including,
Calculating average cell voltage according to the obtained voltage of each cell;
and judging abnormal cells in the two adjacent cells according to the average cell voltage.
For example, one battery pack is composed of 4 cells whose voltages are 3.6V, 3.7V, 3.5V and 3.9V, respectively, and the adaptive voltage difference threshold is 0.2V. First, the voltage difference between the 4 cells is 0.1V, 0.2V, 0.4V in sequence, and the voltage difference between the 3.5V and 3.9V cells exceeds the adaptive voltage difference threshold. Next, the average cell voltage may be calculated by adding the voltage values of all the cells and dividing by the number of cells, i.e., (3.6+3.7+3.5+3.9)/4=3.675V, resulting in an average cell voltage of 3.65V. And finally, judging the abnormal cells in the adjacent cells according to the average cell voltage, wherein the difference between the 3.9V cell and the average cell voltage of 3.675 is larger than the difference between the 3.5V cell and the average cell voltage of 3.675, and judging the 3.9V cell as the abnormal cell.
In the embodiment, the abnormal cells in the two adjacent cells are distinguished by calculating the average cell voltage, so that the abnormal cells in the battery pack are rapidly and simply detected and identified.
Optionally, the abnormal cell in the two adjacent cells is discriminated according to the average cell voltage, including,
When the difference between the high-voltage cell and the average cell voltage in the two adjacent cells is smaller than the difference between the low-voltage cell and the average cell voltage in the two adjacent cells, judging that the high-voltage cell in the two adjacent cells is an abnormal cell;
And when the difference between the high-voltage cell and the average cell voltage in the two adjacent cells is larger than the difference between the low-voltage cell and the average cell voltage in the two adjacent cells, judging that the low-voltage cell in the two adjacent cells is an abnormal cell.
Fig. 2 is a schematic diagram of an unbalanced cell structure according to an embodiment of the present invention, as shown in fig. 2.
In a battery pack, there may be a difference in voltage difference between adjacent cells, wherein the abnormal voltage difference may be caused by one of the cells, not necessarily both cells, causing a problem at the same time. Then, by observing and analyzing the asymmetry of the voltage difference, the abnormal battery cell can be deduced, and measures can be timely taken to solve the problem, so that the safety of the battery pack is ensured.
The voltage of each cell is obtained and the average cell voltage is calculated, so that a reference value can be obtained, then after the voltage difference between two adjacent cells and the adaptive voltage difference threshold are compared, two adjacent cells with the voltage difference between the two adjacent cells larger than the adaptive voltage difference threshold are selected, the difference between the cell with high voltage and the average cell voltage in the adjacent cells and the difference between the cell with low voltage and the average cell voltage are compared, when the difference between the cell with high voltage and the average cell voltage is smaller than the difference between the cell with low voltage and the average cell voltage, the cell with high voltage can be judged to be an abnormal cell, and conversely, when the difference between the cell with high voltage and the average cell voltage is larger than the difference between the cell with low voltage and the average cell voltage, the cell with low voltage can be judged to be an abnormal cell.
In the embodiment, the abnormal battery cell is rapidly and simply distinguished by comparing the difference between the battery cell with high voltage and the average battery cell voltage with the difference between the battery cell with low voltage and the average battery cell voltage, so that the safety and the reliability of the battery system are improved.
S104, carrying out multistage balance management on the abnormal battery cells.
In this embodiment, the abnormal battery cells are managed in a multistage balance manner, so that individual management and adjustment can be performed on different battery packs according to actual requirements, the effect and adaptability of battery cell management are improved, and the reliability of the whole battery system is enhanced.
Optionally, the abnormal cells are subjected to multi-level balancing management, including,
Performing primary balance management on the abnormal battery cells;
After the primary balance management, judging whether the two adjacent battery cells are still in an abnormal state or not again;
And when the voltage difference between two adjacent cells is still larger than the self-adaptive voltage difference threshold value, performing secondary balance management on the abnormal cells.
For example, one battery pack is composed of 4 cells whose voltages are 3.6V, 3.7V, 3.5V and 3.9V, respectively, and the adaptive voltage difference threshold is 0.2V. The voltage difference between the 3.5V and 3.9V battery cells exceeds the self-adaptive voltage difference threshold, the average battery cell voltage is 3.65V through calculation, then the abnormal battery cell is 3.9V battery cell through judgment, the new voltage value obtained after the first-level balance management is 3.85V on the battery cell, the voltage of the 4 battery cells is 3.6V, 3.7V, 3.5V and 3.85V, and the voltage difference between the 3.5V and 3.9V battery cells still exceeds the self-adaptive voltage difference threshold, which means that the voltage change amplitude of the abnormal battery cell is smaller after the first-level balance management, and the second-level balance management on the abnormal battery cell is needed to be continued.
In this embodiment, after the primary balance management, whether two adjacent cells are still in an abnormal state is determined again, if the voltage difference between the two adjacent cells is still greater than the adaptive voltage difference threshold, the secondary balance management is needed, and if the primary balance management does not reach the expected condition, the secondary balance management is set to continuously manage the abnormal cells, so that the safety of the battery system is further ensured, and the balance of the battery cells is ensured.
Alternatively, a level of balancing management, including,
When the abnormal battery cell is a battery cell with high voltage in two adjacent battery cells, connecting the battery cell with high voltage in the two adjacent battery cells with a preset first resistor;
When the abnormal battery cell is a battery cell with low voltage in the two adjacent battery cells, a control switch between a battery cell with high voltage in the two adjacent battery cells and a battery cell with low voltage in the two adjacent battery cells is opened, and charges in the battery cell with high voltage in the two adjacent battery cells are transferred to the battery cell with low voltage in the two adjacent battery cells through the control switch.
For example, one battery pack is composed of 4 cells whose voltages are 3.6V, 3.7V, 3.5V, and 3.9V, respectively. When the 3.9V battery cell is an abnormal battery cell after the judgment, the battery cell is a battery cell with high voltage in two adjacent battery cells, in the primary balance management process, the battery cell with the voltage of 3.9V is connected with a preset first resistor, the voltage of the battery cell with the voltage of 3.9V is reduced to 3.8V, and the primary balance management is completed, wherein the resistance value of the preset first resistor can be set according to actual conditions; when the 3.5V battery cell is an abnormal battery cell after being judged, the battery cell is a battery cell with low voltage in two adjacent battery cells, in the primary balance management process, a control switch between the 3.5V battery cell and the 3.9V battery cell is opened, and the charge in the 3.9V battery cell is transferred to the 3.5V battery cell through the control switch, so that the voltage of the 3.5V battery cell is increased to a level close to the voltage of the 3.9V battery cell, for example, to about 3.8V.
In this embodiment, different processing manners are adopted according to different situations, so as to realize charge balance between the battery cells, and by means of connecting the battery cells with high voltage with a connection resistor and connecting the battery cells with low voltage with a control switch, the voltage difference between adjacent battery cells is effectively reduced, and the performance and safety of the battery are improved, so that the balance management effect of the battery cells in the battery is optimized.
Optionally, a secondary balance management, including,
When the abnormal battery cell is a battery cell with high voltage in the two adjacent battery cells, the battery cell with high voltage in the two adjacent battery cells is connected with a preset second resistor;
When the abnormal battery cell is a battery cell with lower voltage in the two adjacent battery cells, an energy transfer circuit between a battery cell with high voltage in the two adjacent battery cells and a battery cell with low voltage in the two adjacent battery cells is opened, and charges in the battery cell with high voltage in the two adjacent battery cells are transferred to the battery cell with low voltage in the two adjacent battery cells through the energy transfer circuit;
the preset second resistance value is larger than the preset first resistance value.
Fig. 3 is a schematic diagram of an energy transfer circuit according to an embodiment of the invention, as shown in fig. 3.
The energy transfer circuit adopts a single-inductance structure and comprises a switching element 31, an inductance 32 and a capacitance 33, wherein the inductance 32 is used for storing and transmitting energy, the capacitance 33 is used for filtering and adjusting voltage, and the switching element 31 is used for controlling the transmission and transfer of energy between two adjacent battery cells.
The energy transfer circuit connects the inductor to the higher voltage cell 34 to obtain energy from the high voltage cell 34, and controls connection and disconnection between the inductor and the lower voltage cell 35 through the switching element 31. When the energy transfer circuit is turned on (i.e. the switching element 31 is turned off), the inductor 32 absorbs energy from the high-voltage battery cell 34 and transmits the energy to the battery cell 35 with lower voltage, so that charge balance is realized, and redundant energy in the high-voltage battery cell 34 is transferred to the battery cell 35 with lower voltage, so that charge distribution of the whole battery pack is more balanced, energy utilization efficiency of the battery pack is improved, and service life of the battery pack is prolonged. When the energy transfer circuit is disconnected (i.e. the switching element 31 is connected), the inductor 32 is disconnected from the cell 35 with lower voltage, so as to prevent energy from flowing backward, ensure that energy is only transmitted when needed, avoid energy waste and unnecessary loss, and by accurately controlling the on and off of the switching element 31, the energy transfer circuit can flexibly adjust the energy transfer process according to the state between two adjacent cells, so as to realize the optimal charge balance effect. In addition, the capacitor 33 plays a role in filtering in the energy transfer circuit, can smooth voltage fluctuation in the circuit, keeps stability of the circuit, and can eliminate voltage peaks and interference through the filtering function of the capacitor 33, provide stable power supply output and ensure normal operation of other electronic equipment and systems.
In this embodiment, on the basis of the primary balance management, the secondary balance management is performed, when the abnormal battery cell is a battery cell with a high voltage in two adjacent battery cells, the voltage in the battery cell with the high voltage is reduced by connecting the second resistor, compared with the preset first resistor, the resistance value of the preset second resistor is larger, and the flow speed of charges can be limited by the secondary balance management with stronger control force than the primary balance management, so that more gentle charge balance is realized.
Optionally, characterized in that,
After primary balance management, the voltage difference between two adjacent cells is reduced to be within a self-adaptive voltage difference threshold value, a cell with high voltage in the two adjacent cells is disconnected with a preset first resistor, or a control switch between the cell with high voltage in the two adjacent cells and the cell with low voltage in the two adjacent cells is closed, so that the initial connection state between the two adjacent cells is restored;
after the secondary balance management, the voltage difference between two adjacent cells is reduced to be within the self-adaptive voltage difference threshold value, and the current connection state between the two adjacent cells is maintained;
after the secondary balance management, the voltage difference between two adjacent battery cells is still larger than the self-adaptive voltage difference threshold value, and the power supply of the battery is cut off.
In this embodiment, since the primary balance management adjusts the voltage of the abnormal cell only by a low-power manner, if the voltage difference between two adjacent cells is restored to be within the adaptive voltage difference threshold after the primary balance management, the primary balance management proves to be effective, and the effective balance management can be achieved by a weak adjustment manner, so that the adjustment does not need to be continuously maintained.
In this embodiment, since the second-level balancing management adjusts the voltage of the abnormal cell by a high-power manner, if the voltage difference between two adjacent cells is restored to be within the adaptive voltage difference threshold after the second-level balancing management, the adjustment manner still needs to be maintained.
In this embodiment, after the primary balance management, when the voltage difference between two adjacent cells is reduced to be within the adaptive voltage difference threshold, no additional charge transfer is required, and the energy loss and heat generation can be reduced by recovering the initial connection state between the two adjacent cells, so as to enhance the efficiency of the battery; after the secondary balance management, when the voltage difference between two adjacent cells is reduced to be within the self-adaptive voltage difference threshold, the current connection state between the two adjacent cells is maintained, so that frequent charge transfer can be reduced, and the service life of the battery is prolonged; after the secondary balance management, the voltage difference between two adjacent battery cells is still larger than the self-adaptive voltage difference threshold value, the power supply of the battery is cut off, the safety of the battery is protected, and the stability and the reliability of the battery are ensured.
FIG. 4 is a flow chart of multi-level balancing management according to an embodiment of the present invention. How to perform multi-level balancing management on the abnormal cells is described in detail below with reference to fig. 4.
Step 1, performing primary balance management on abnormal battery cells;
Step 2, judging that the voltage difference between two adjacent cells is still larger than the self-adaptive voltage difference threshold, if yes, turning to step 3, and if not, recovering the initial connection state between the two adjacent cells;
step3, performing secondary balance management on the abnormal battery cells;
Step 4, judging that the voltage difference between two adjacent cells is still larger than the self-adaptive voltage difference threshold, if yes, turning to step 5, and if not, maintaining the connection state between the two adjacent cells;
and 5, cutting off the power supply of the battery to prevent the battery from being further damaged by the abnormal battery cell.
In this embodiment, the balance adjustment is performed on the abnormal battery cells by the hierarchical management measures of the primary balance management and the secondary balance management, so that the balance effect of the battery cells is improved. Whether the voltage difference between the two adjacent electric cores is restored to the self-adaptive voltage difference threshold value is continuously judged, and corresponding treatment can be carried out on connection between the two adjacent electric cores in time according to whether the voltage difference between the two adjacent electric cores is restored to the self-adaptive voltage difference threshold value, so that negative effects on the performance and safety of the whole battery caused by long-time balance management are avoided. When the abnormal battery cell still cannot reach a proper voltage range through secondary balance management, a measure of cutting off a battery power supply is adopted, so that the abnormal battery cell can be prevented from further damaging the battery, and the safety of the whole system is ensured.
According to the battery cell balance management method provided by the embodiment, the voltage of each cell in the battery is obtained, the voltage difference between the adjacent cells is calculated according to the obtained voltage of each cell, the self-adaptive voltage difference threshold of the battery is calculated according to the capacity attenuation of the battery, the temperature change of the battery and the preset basic voltage difference between each cell, when the voltage difference between the two adjacent cells is larger than the self-adaptive voltage difference threshold, the abnormal cell in the two adjacent cells is judged, and the abnormal cell is subjected to multistage balance management. That is, by acquiring the voltage of each cell and calculating the voltage difference between adjacent cells, the state of the battery system can be monitored; the self-adaptive voltage difference threshold is calculated according to the capacity attenuation, the temperature change and the preset basic voltage difference of the battery, the threshold can be dynamically adjusted according to actual conditions, the change of the battery system under different working conditions is adapted, and the stability of the system is improved; when the voltage difference between two adjacent cells is larger than the self-adaptive voltage difference threshold, abnormal cells in the two adjacent cells can be timely distinguished, unbalance among the cells is reduced, and the risk of overcharging or overdischarging of the cells is reduced, so that the service life of a battery system is prolonged; the abnormal cells are subjected to multistage balance management, so that the voltage between the cells can be kept within a reasonable range, the balance state between the cells is better controlled, and the stability of the system is further enhanced.
The method for managing cell balance of a battery provided by the embodiment of the application is described in detail above with reference to fig. 1 to 4. The following describes in detail a battery cell balance management apparatus for executing the battery cell balance management method provided by the embodiment of the present application with reference to fig. 5.
Fig. 5 is a schematic structural diagram of a battery cell balance management system according to an embodiment of the present invention. Referring to fig. 5, the system includes:
The acquisition module 501 is configured to acquire a voltage of each cell in the battery, and calculate a voltage difference between adjacent cells according to the acquired voltage of each cell;
a calculating module 502, configured to calculate an adaptive voltage difference threshold of the battery according to a capacity fade of the battery, a temperature change of the battery, and a preset basic voltage difference between each of the battery cells;
A discriminating module 503, configured to discriminate an abnormal cell of the two adjacent cells when the voltage difference between the two adjacent cells is greater than the adaptive voltage difference threshold;
the balance management module 504 is configured to perform multi-level balance management on the abnormal cells.
The technical effects of the battery cell balance management system refer to the technical effects of the battery cell balance management method, and are not described herein.
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The units or modules involved in the embodiments of the present invention may be implemented in software or in hardware. The described units or modules may also be provided in a processor, for example, as: a processor includes an acquisition module 501, a calculation module 502, a discrimination module 503, and a balance management module 504, where the names of these modules do not in some cases define the module itself.
The above description is only illustrative of the preferred embodiments of the present invention and of the principles of the technology employed. It will be appreciated by persons skilled in the art that the scope of the invention referred to in the present invention is not limited to the specific combinations of the technical features described above, but also covers other technical features formed by any combination of the technical features described above or their equivalents without departing from the inventive concept. Such as the above-mentioned features and the technical features disclosed in the present invention (but not limited to) having similar functions are replaced with each other.

Claims (9)

1. A method for managing cell balance of a battery, the method comprising:
Acquiring the voltage of each cell in the battery, and calculating the voltage difference between adjacent cells according to the acquired voltage of each cell;
Calculating an adaptive voltage difference threshold of the battery according to the capacity attenuation of the battery, the temperature change of the battery and the preset basic voltage difference between each battery core;
when the voltage difference between two adjacent cells is larger than the self-adaptive voltage difference threshold, judging abnormal cells in the two adjacent cells;
performing multistage balance management on the abnormal battery cells;
Said calculating an adaptive voltage difference threshold for said battery based on a capacity fade of said battery, a temperature change of said battery, and a preset base voltage difference between said each cell, comprising,
Calculating a capacity fading factor of the battery according to the current capacity of the battery and the capacity of a preset new battery;
Acquiring a temperature change factor of the battery according to the temperature change of the battery and a preset temperature factor table;
And calculating the product of the preset basic voltage difference between each battery core, the capacity attenuation factor of the battery and the temperature change factor of the battery to obtain the self-adaptive voltage difference threshold of the battery.
2. The method of claim 1, wherein discriminating between abnormal cells in two adjacent cells when the voltage difference between the two adjacent cells is greater than the adaptive voltage difference threshold comprises,
Calculating average cell voltage according to the obtained voltage of each cell;
And judging abnormal cells in the two adjacent cells according to the average cell voltage.
3. The method of claim 2, wherein said determining abnormal cells among said two adjacent cells based on said average cell voltage comprises,
When the difference value between the high-voltage cell and the average cell voltage in the two adjacent cells is larger than the difference value between the low-voltage cell and the average cell voltage in the two adjacent cells, judging that the high-voltage cell in the two adjacent cells is an abnormal cell;
And when the difference value between the high-voltage cell and the average cell voltage in the two adjacent cells is smaller than the difference value between the low-voltage cell and the average cell voltage in the two adjacent cells, judging that the low-voltage cell in the two adjacent cells is an abnormal cell.
4. The method of claim 1, wherein said performing multi-level balancing management on said abnormal cells comprises,
Performing primary balance management on the abnormal battery cells;
after the primary balance management, judging whether the two adjacent battery cores are still in an abnormal state or not again;
and when the voltage difference between the two adjacent battery cells is still larger than the self-adaptive voltage difference threshold value, performing secondary balance management on the abnormal battery cells.
5. The method of claim 4, wherein said primary balancing management comprises,
When the abnormal battery cell is a battery cell with high voltage in the two adjacent battery cells, connecting the battery cell with high voltage in the two adjacent battery cells with a preset first resistor;
When the abnormal battery cell is a battery cell with low voltage in the two adjacent battery cells, a control switch between a battery cell with high voltage in the two adjacent battery cells and a battery cell with low voltage in the two adjacent battery cells is opened, and charges in the battery cell with high voltage in the two adjacent battery cells are transferred to the battery cell with low voltage in the two adjacent battery cells through the control switch.
6. The method of claim 4, wherein said secondary balancing management comprises,
When the abnormal battery cell is a battery cell with high voltage in the two adjacent battery cells, connecting the battery cell with high voltage in the two adjacent battery cells with a preset second resistor;
When the abnormal battery cell is a battery cell with low voltage in the two adjacent battery cells, an energy transfer circuit between a battery cell with high voltage in the two adjacent battery cells and a battery cell with low voltage in the two adjacent battery cells is opened, and charges in the battery cell with high voltage in the two adjacent battery cells are transferred to the battery cell with low voltage in the two adjacent battery cells through the energy transfer circuit;
the preset second resistance value is larger than the preset first resistance value.
7. The method for managing cell balance according to claim 5 or 6, wherein,
After the primary balance management, the voltage difference between the two adjacent electric cores is reduced to be within the self-adaptive voltage difference threshold value, the electric core with high voltage in the two adjacent electric cores is disconnected with a preset first resistor, or a control switch between the electric core with high voltage in the two adjacent electric cores and the electric core with low voltage in the two adjacent electric cores is closed, and the initial connection state between the two adjacent electric cores is restored;
After the secondary balance management, the voltage difference between the two adjacent electric cores is reduced to be within the self-adaptive voltage difference threshold value, and the current connection state between the two adjacent electric cores is maintained;
after the secondary balance management, the voltage difference between the two adjacent battery cells is still larger than the self-adaptive voltage difference threshold value, and the power supply of the battery is cut off.
8. The method of claim 1, wherein the step of obtaining the voltage of each cell in the battery and calculating the voltage difference between the adjacent cells based on the obtained voltage of each cell comprises,
The voltage of each cell in the battery was cyclically measured every 3 hours.
9. A battery cell balance management system, the system comprising:
The acquisition module is used for acquiring the voltage of each electric core in the battery and calculating the voltage difference between the adjacent electric cores according to the acquired voltage of each electric core;
The calculation module is used for calculating an adaptive voltage difference threshold value of the battery according to the capacity attenuation of the battery, the temperature change of the battery and the preset basic voltage difference between each battery core;
the judging module is used for judging abnormal cells in the two adjacent cells when the voltage difference between the two adjacent cells is larger than the self-adaptive voltage difference threshold;
The balance management module is used for carrying out multistage balance management on the abnormal battery cells;
Said calculating an adaptive voltage difference threshold for said battery based on a capacity fade of said battery, a temperature change of said battery, and a preset base voltage difference between said each cell, comprising,
Calculating a capacity fading factor of the battery according to the current capacity of the battery and the capacity of a preset new battery;
Acquiring a temperature change factor of the battery according to the temperature change of the battery and a preset temperature factor table;
And calculating the product of the preset basic voltage difference between each battery core, the capacity attenuation factor of the battery and the temperature change factor of the battery to obtain the self-adaptive voltage difference threshold of the battery.
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