A battery pack charge and discharge balance control method and system

Abstract

The present invention discloses a battery pack charge and discharge balance control method and system, which relates to the field of battery charge and discharge control. In the system, the pth first gate switch in the first FPGA is connected in parallel with the pth battery cell. When the battery pack is to be used to discharge to the load, the current remaining maximum capacity of the battery cell is determined to determine the predicted remaining life; based on the predicted remaining life, the on-off time function of the battery cell is determined and the on and off of the first gate switch corresponding to the battery cell is controlled according to the on-off time function, so that the total discharge power of the battery pack reaches the target output power; in the process of charging or discharging the battery pack, when it is determined that the battery cell is in a state to be stopped from charging and discharging, the corresponding first gate switch is controlled to be turned on to avoid damage to the corresponding battery cell. The present application can realize charge and discharge control according to the actual situation of the battery cell, and effectively realize the precise control of each battery cell and the balanced control of the entire battery pack.

Description

Technical Field

[0001] The present invention relates to the technical field of battery charge and discharge control, and in particular to a battery pack charge and discharge balance control method and system. Background Art

[0002] Electric vehicles have become a means of transportation that occupies a considerable market share. Research on the long and short battery life issues of electrochemical batteries in electric vehicles is of considerable value and will help better promote the development of sustainable electric vehicle technology.

[0003] Specifically, electric vehicles use a battery pack consisting of multiple battery cells as a power source to meet the voltage and power requirements of the motor and other electrical systems and accessories on the electric vehicle. After several charge and discharge cycles, the material properties of the electrochemical battery may change slightly due to chemical reactions, resulting in an imbalance in voltage and charge between the battery cells. This imbalance may cause abnormal charging and discharging and excessive aging of some battery cells. The performance and chemical properties of the battery cells may be damaged. Continuing to repeat the charge and discharge cycle in this unbalanced state is likely to affect the performance of the entire battery pack and shorten the service life of the battery cells and the entire battery pack. To this end, the following methods are mainly used in the prior art to achieve balanced control:

[0004] The first method is centralized control, please refer to Figure 1 , using a controller for centralized control and various control algorithms to balance the battery cells. This control scheme is simple in structure, but there are certain differences in the states of the battery cells, and as the number of charge and discharge cycles increases, this difference gradually increases. Therefore, in practical applications, it is usually necessary to design a fairly complex algorithm to achieve balance.

[0005] The second method is distributed control, please refer to Figure 2 A separate controller is designed for each battery cell, and a supervisory controller is set up to monitor each battery cell and the entire battery pack. However, the design and implementation costs of this method are huge, and it is difficult to promote and apply it effectively.

[0006] Therefore, how to design a more effective control scheme to monitor the status of each battery cell in a battery pack to achieve charge and discharge balance is a problem that needs to be solved urgently. Summary of the invention

[0007] The problem solved by the present invention is to provide a battery pack charge and discharge balance control method and system, which can realize charge and discharge control according to the actual situation of the battery unit, and finally effectively realize accurate control of each battery unit and balance control of the entire battery pack.

[0008] To solve the above problems, the present invention provides a battery pack charge and discharge balance control method, which is applied to a control module in a battery pack charge and discharge balance control system. The battery pack charge and discharge balance control system also includes a first FPGA connected to the control module, the first FPGA includes A first gate switches, the battery pack includes B battery cells connected in series, the pth first gate switch is connected in parallel with the pth battery cell, A is an integer not less than B, B is an integer greater than 1, 1≤p≤B and p is an integer, and the battery pack charge and discharge balance control method includes:

[0009] When the battery pack is to be used to discharge to a load, determining the current remaining maximum capacity of the battery unit;

[0010] Determining the predicted remaining life of the battery cell according to the remaining maximum capacity and a preset life prediction strategy;

[0011] Determine an on-off time function of the battery unit based on the predicted remaining life, and control the on and off of a first gate-controlled switch corresponding to the battery unit according to the on-off time function, so that the total discharge power of the battery pack reaches a target output power;

[0012] During the process of charging or discharging the battery pack, characteristic information corresponding to the battery cell in the current charging and discharging state is obtained, so that when it is determined according to the characteristic information that the battery cell is in the state to stop charging and discharging, the corresponding first gate switch is controlled to be turned on.

[0013] The beneficial effects of the present invention are as follows: the first FPGA used in this application has high logic density and high reliability, which is conducive to programming control and cost reduction; through the cooperation of the first FPGA and the method logic, charging and discharging control can be achieved according to the actual situation of the battery cell, and ultimately, precise control of each battery cell and balanced control of the entire battery pack can be effectively achieved, which is conducive to practical application.

[0014] Further, determining the predicted remaining life corresponding to the battery unit according to the remaining maximum capacity and a preset life prediction strategy includes:

[0015] Determine the total number of charge and discharge cycles of the battery cell at the remaining maximum capacity according to the corresponding relationship between the preset capacity and the number of cycles of the battery cell;

[0016] The difference between the total number of charge and discharge cycles that can be cycled and the current number of charge and discharge cycles corresponding to the battery cell is determined as the predicted remaining life of the battery cell.

[0017] Furthermore, the preset capacity-cycle number correspondence relationship corresponding to the p-th battery cell is determined based on a first preset relationship, and the first preset relationship is:

[0018] ,

[0019] in, It represents the maximum remaining capacity of the p-th battery cell after the current k-th charge and discharge cycle. is the first fitting parameter, is the second fitting parameter, and The remaining maximum capacity matrix is ​​determined by least square fitting, wherein the remaining maximum capacity matrix is ​​obtained based on q remaining maximum capacities determined after q charge and discharge cycles within the basic use time, where q is an integer greater than 1.

[0020] Furthermore, it also includes:

[0021] Determine the distance from the last update and Whether the preset cycle number threshold has been exceeded;

[0022] If so, re-fit the remaining maximum capacity determined within the preset cycle number threshold to determine the and , so as to re-determine the and The preset capacity-cycle number correspondence is updated.

[0023] In this scheme, the above settings can be used to update the fitted and , which is conducive to correcting the preset capacity-cycle number correspondence and more accurately determining the predicted remaining life of the battery cell.

[0024] Further, determining that the battery unit is in a state to be stopped from charging and discharging according to the characteristic information includes:

[0025] Determine whether any one of the first event, the second event, the third event or the fourth event occurs; the first event is that the charging voltage of the battery cell is greater than a preset saturation voltage, the second event is that the charging current of the battery cell is greater than a preset current threshold, the third event is that the current temperature at the location of the battery cell is greater than a preset temperature threshold, and the fourth event is that the temperature rise rate corresponding to the battery cell exceeds a preset speed threshold;

[0026] If so, it is determined that the battery unit is in a state to be stopped from charging and discharging; if not, the original state is maintained.

[0027] In this solution, the above-mentioned settings can better monitor the status of each battery cell, facilitate accurate charge and discharge control, and facilitate protection of the battery cells.

[0028] Furthermore, it also includes:

[0029] Determine whether there is a target battery cell, and the sum of a first historical number of occurrences of the third event and a second historical number of occurrences of the fourth event in the target battery cell is greater than a preset allowable threshold;

[0030] If so, shorten the conduction time corresponding to the target battery cell and extend the conduction time of the remaining battery cells to ensure that the total discharge power of the battery pack reaches the target output power; if not, do not take any intervention measures.

[0031] In this solution, the above settings can protect the target battery cell to the greatest extent, which is beneficial to improving the service life of the entire battery pack.

[0032] Further, determining the on-off time function of the battery unit based on the predicted remaining life includes:

[0033] An evaluation parameter characterizing the aging degree of the battery cell is determined based on the predicted remaining life of the battery cell and a second preset relationship, wherein the second preset relationship is:

[0034] ,

[0035] in, is the evaluation parameter, is the predicted remaining life, represents the sum of the predicted remaining lifespans corresponding to the battery cells;

[0036] The on-off time function is determined according to the on-off time ratio and the frequency parameter characterizing the on-off switching situation, wherein the on-off time ratio and the frequency parameter are both negatively correlated with the evaluation parameter.

[0037] In this solution, the above settings can be used to implement output control of the battery cells in combination with the aging degree of the battery cells, thereby avoiding overcharging or over-discharging of severely aged battery cells, thereby avoiding unnecessary safety problems and helping to increase the service life of the entire battery pack.

[0038] The present invention also provides a battery pack charge and discharge balance control system, comprising a control module and a first FPGA connected to the control module;

[0039] The first FPGA includes A first gate-controlled switches, the battery pack includes B battery cells connected in series, the pth first gate-controlled switch is connected in parallel with the pth battery cell, A is an integer not less than B, B is an integer greater than 1, 1≤p≤B and p is an integer;

[0040] The control module is used to implement the steps of the battery pack charge and discharge balance control method as described above when executing a computer program.

[0041] Furthermore, it also includes a group B detection module, and the p-th group detection module is connected in parallel with the p-th battery unit;

[0042] The p-th group of detection modules includes a voltage detection module, a controllable switch module and a current detection module, wherein the controllable switch module is connected in series with the current detection module and the series circuit is connected in parallel with the voltage detection module; the voltage detection module, the current detection module and the controllable switch module are all connected to the control module;

[0043] The controllable switch module is used to be turned on and off according to the control instruction of the control module, and the control instruction satisfies that the controllable switch module and the first gate-controlled switch corresponding to the pth battery unit are not turned on at the same time.

[0044] In this solution, the above settings can reliably detect the current output state of the battery pack, making it easier for the control module to grasp the working conditions of the battery unit according to the detection results, and the detection process does not affect the normal operation of the battery unit.

[0045] Further, the controllable switch module in the p-th group of detection modules is the p-th second gate-controlled switch in the second FPGA, and the second FPGA includes M second gate-controlled switches and M is an integer not less than B. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a schematic diagram of a structure for realizing charge and discharge balance control of a battery pack in the prior art;

[0047] Figure 2 It is a schematic diagram of another structure for realizing balanced control of battery pack charge and discharge in the prior art;

[0048] Figure 3 A schematic structural diagram of a modular battery pack provided by the present invention;

[0049] Figure 4 A flow chart of a battery pack charge and discharge balancing control method provided by the present invention;

[0050] Figure 5 A schematic diagram of a first FPGA and a battery pack provided by the present invention;

[0051] Figure 6 A schematic diagram of the structure of a battery pack charge and discharge balance control system provided by the present invention;

[0052] Figure 7 A schematic diagram of a battery unit output state provided by the present invention;

[0053] Figure 8 A schematic diagram of a curve showing a corresponding relationship between a preset capacity and the number of cycles provided by the present invention;

[0054] Fig. 9 A working schematic diagram of a first FPGA provided by the present invention;

[0055] Fig.10 A working schematic diagram of a second FPGA 3 provided by the present invention;

[0056] Description of reference numerals:

[0057] W1-controller corresponding to battery cell 1, W2-controller corresponding to battery cell 2, W3-controller corresponding to battery cell 3, W4-controller corresponding to battery cell 4, W-supervisory controller, 1-battery pack, 11-battery cell, 12-temperature sensor, 2-first FPGA, 3-second FPGA, 21-the first first gate switch in the first FPGA, 31-the second switch in the second FPGA, 4-current detection module, 5-voltage detection module. DETAILED DESCRIPTION

[0058] 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.

[0059] The present invention provides an embodiment, a battery pack charge and discharge balance control method, which is applied to a control module in a battery pack charge and discharge balance control system, the battery pack charge and discharge balance control system also includes a first FPGA2 connected to the control module, the first FPGA2 includes A first gate switches, the battery pack 1 includes B battery cells connected in series, the pth first gate switch is connected in parallel with the pth battery cell, A is an integer not less than B, B is an integer greater than 1, 1≤p≤B and p is an integer, the battery pack charge and discharge balance control method includes:

[0060] S11: when the battery pack 1 is to be used to discharge to the load, determining the current maximum remaining capacity of the battery unit;

[0061] S12: Determine the predicted remaining life of the battery cell according to the remaining maximum capacity and the preset life prediction strategy;

[0062] S13: determining an on-off time function of the battery cell based on the predicted remaining life, and controlling the on and off of the first gate-controlled switch corresponding to the battery cell according to the on-off time function, so that the total discharge power of the battery pack 1 reaches the target output power;

[0063] S14: During the process of charging or discharging the battery pack 1 , characteristic information corresponding to the battery cell in the current charging and discharging state is obtained, so as to control the corresponding first gate switch to be turned on when it is determined that the battery cell is in the state to be stopped charging and discharging according to the characteristic information.

[0064] Specifically, the battery pack 1 is used in practical applications but is not limited to: Figure 3 The modular array shown may include multiple battery cells connected in series (to avoid confusion, Figure 3 In the figure, only the battery cell 11 in the upper left corner is used as an example for marking); in addition, in actual applications, when multiple battery packs are provided on an electric vehicle, the multiple battery packs can be used in series or in parallel to output according to power demand, and no special limitation is made here.

[0065] Considering that FPGA (Field-Programmable Gate Array) has high logic density and high reliability, and is convenient for user programming control, the use of this technology can reduce the design and maintenance risks of the system and help reduce the design cost. Therefore, the first FPGA2 is set in the manner described in the above embodiment, and the A first gate switches in the first FPGA2 are all controlled by the control module. Please refer to Figure 5 , taking the battery pack 1 in a modular array form as an example, the first FPGA2 will perform array encoding according to the actual physical position of the battery pack 1, that is, each first gate switch in the first FPGA2 is set correspondingly thereto, such as the first gate switch in the first FPGA2 in the row Io1 and column IoA corresponds to the battery cell in the row A and column 1 of the battery pack 1, the first gate switch in the first FPGA2 in the row Io1 and column IoB corresponds to the battery cell in the row A and column 2 of the battery pack 1, and so on, which will not be elaborated here; it can be understood that, Figure 5 The corresponding setting relationship between the first FPGA2 and the battery cells in the battery pack is mainly explained, and in order to avoid confusion in wiring, the connection relationship when the first gate switch is specifically connected in parallel with the battery cell and the connection relationship with the control module are not shown.

[0066] Please refer to Figure 6 , Figure 6As a schematic diagram, a connection schematic diagram is given when the battery pack 1 includes 4 battery cells (i.e., B=4) (due to the limitation of the picture display focus and to avoid confusion in the connection, the setting diagram of the control module is not shown. As for the connection between the control module and the first gate-controlled switch and the second gate-controlled switch in the following embodiments, please refer to the text description). Taking the first battery cell from the left as an example, a setting diagram when the first first gate-controlled switch 21 is connected in parallel with the first battery cell is given. The remaining battery cells are similar, and no further description is given to avoid confusion in the connection. It should be noted that the reason why the first FPGA2 including A first gate-controlled switches not less than B is selected here is to meet the one-to-one correspondence with the battery cells in the battery pack 1, and when A is greater than B, the first FPGA2 has some alternative options, so that there are spare switches available when any first gate-controlled switch fails.

[0067] It should also be noted that the battery pack 1 can be installed on an electric vehicle and used as a power source, and the load here can be various power loads on the electric vehicle; when the battery pack 1 is to be used to discharge to the load, the current remaining maximum capacity of the battery cell is determined, and the remaining maximum capacity represents the actual available capacity that the battery cell can reach after multiple charge and discharge cycles (the actual available capacity will decay with the cycle relative to the rated capacity at the time of leaving the factory, that is, capacity decay), and the remaining maximum capacity can be determined by determining the working power using the working voltage and working current of the battery cell during operation, and determining the remaining maximum capacity of the battery cell based on the working power, working voltage, working current and internal resistance of the battery cell.

[0068] Subsequently, considering that each battery cell is an independent individual and its life span is not uniformly decayed, S12 is used to determine the corresponding predicted remaining life span of each battery cell, so as to control the first gate switch corresponding to the battery cell according to the life span and S13. Specifically, when the first gate switch is turned on, the output or charging input of the corresponding battery cell is cut off; when the first gate switch is turned off, the corresponding battery cell can work normally; it can be understood that the on-off time functions corresponding to different battery cells are usually different, and the corresponding output states are also different, please refer to Figure 7 , Figure 7 A schematic diagram of a battery cell output state provided by the present invention; ultimately the total discharge power of the battery pack 1 reaches the target output power to realize power supply to the load; it can be understood that the total discharge power here is the sum of the product of the output voltage, output current and on-off time function of each battery cell.

[0069] During the process of charging the battery pack 1 or discharging the battery pack 1 to the load, characteristic information corresponding to the battery cell in the current charging state or discharging state is obtained, where the characteristic information is voltage information and / or current information and / or temperature information. Then, when it is determined that the battery cell is in a stop charging and discharging state based on the characteristic information, indicating that the battery cell is not suitable for further charging or discharging, the corresponding first gate switch is controlled to be turned on to achieve rapid shutdown and isolation.

[0070] In summary, the present application provides a battery pack charge and discharge balance control method, which can realize charge and discharge control according to the actual situation of the battery cell through the cooperation of the first FPGA2 and the method logic, and finally effectively realize the precise control of each battery cell and the balance control of the entire battery pack 1, which is beneficial to practical application.

[0071] As a preferred embodiment, determining the predicted remaining life of the battery cell according to the remaining maximum capacity and the preset life prediction strategy includes:

[0072] Determine the total number of cyclic charge and discharge times of the battery cell at the remaining maximum capacity according to the corresponding relationship between the preset capacity and the number of cycles of the battery cell;

[0073] The difference between the total number of charge and discharge cycles that can be cycled and the current number of charge and discharge cycles corresponding to the battery cell is determined as the predicted remaining life of the battery cell.

[0074] Specifically, the preset capacity-cycle number correspondence of different battery cells is different, and the correspondence includes but is not limited to being displayed in the form of a curve during the actual storage process. Please refer to Figure 8 , Figure 8 Three battery cells are taken as an example for explanation, wherein the star curve represents the curve graph corresponding to the first battery cell, the dotted line represents the curve graph corresponding to the second battery cell, and the solid line represents the curve graph corresponding to the third battery cell. Assuming that the remaining maximum capacity corresponding to the three battery cells is 80% of the full capacity state, the total number of cyclic charge and discharge cycles corresponding to each of them is different, and the corresponding predicted remaining life is different.

[0075] As a preferred embodiment, the preset capacity-cycle number corresponding to the p-th battery cell is determined based on a first preset relationship, and the first preset relationship is:

[0076] ,

[0077] in, It represents the maximum remaining capacity of the p-th battery cell after the current k-th charge and discharge cycle. is the first fitting parameter, is the second fitting parameter, and The remaining maximum capacity matrix is ​​determined by least square fitting, and the remaining maximum capacity matrix is ​​obtained by q remaining maximum capacities determined after q charge and discharge cycles within the basic use time, where q is an integer greater than 1.

[0078] Specifically, a total of q remaining maximum capacities are determined after q charge-discharge cycles within the basic use time, and the q remaining maximum capacities form a remaining maximum capacity matrix, so that the least squares method is used to fit the matrix to determine the remaining maximum capacity. and , thus obtaining the first preset relationship.

[0079] As a preferred embodiment, it also includes:

[0080] Determine the distance from the last update and Whether the preset cycle number threshold has been exceeded;

[0081] If so, re-fit and determine the remaining maximum capacity determined within the preset cycle number threshold and , so that based on the re-determined and Update the preset capacity-cycle number correspondence.

[0082] In this embodiment, although the capacity decay process of lithium batteries is irreversible, the causes of capacity decay, such as decomposition of positive electrode materials, damage to SEI (Solid Electrolyte Interface) on the electrode surface, loss of electrolyte, blockage or damage of diaphragm, shedding of positive and negative electrode materials, etc., may change during use, and the corresponding first preset relationship should also be continuously updated. Specifically, it is determined that the current distance to the last update and Whether the preset cycle number threshold has been exceeded, if not, the predicted remaining life can still be determined based on the currently determined first preset relationship; if so, refit according to the above steps to determine and , to obtain a new first preset relationship, so as to determine the predicted remaining life according to the new first preset relationship and restart the accumulation of the number of cycles.

[0083] It can be seen that the present application can update the fitted and , which is conducive to correcting the preset capacity-cycle number correspondence, more accurately determining the predicted remaining life of the battery cell, and adjusting the output of the battery cell.

[0084] As a preferred embodiment, determining that the battery cell is in a state to be stopped from charging and discharging according to the characteristic information includes:

[0085] Determine whether any one of the first event, the second event, the third event or the fourth event occurs; the first event is that the charging voltage of the battery cell is greater than a preset saturation voltage, the second event is that the charging current of the battery cell is greater than a preset current threshold, the third event is that the current temperature of the location of the battery cell is greater than a preset temperature threshold, and the fourth event is that the heating speed corresponding to the battery cell exceeds a preset speed threshold;

[0086] If so, it is determined that the battery unit is in a state to be stopped from charging and discharging.

[0087] Specifically, if it is determined that the battery cell is in a stop charging and discharging state, the corresponding first gate switch will be turned on to quickly isolate the battery cell, while other battery cells in a normal charging and discharging state will still work normally; the method for obtaining the temperature here can be referred to as Figure 3 As shown, a temperature sensor connected to the control module is provided for each battery cell (such as a temperature sensor 12 is provided for the battery cell 11); it can be understood that a detection device for monitoring the temperature of a certain area can also be installed, and then when the temperature rise rate in a certain area exceeds a preset threshold, the first gate switches corresponding to the battery cells in the control area are all turned on to achieve rapid isolation of the area.

[0088] It can be seen that the above settings can better monitor the status of each battery cell, facilitate accurate charge and discharge control, and protect the battery cells.

[0089] As a preferred embodiment, it also includes:

[0090] Determine whether there is a target battery cell, and the sum of a first historical number of occurrences of the third event and a second historical number of occurrences of the fourth event in the target battery cell is greater than a preset allowable threshold;

[0091] If so, the conduction time corresponding to the target battery cell is shortened and the conduction time of the remaining battery cells is prolonged to ensure that the total discharge power of the battery pack 1 reaches the target output power.

[0092] Specifically, during the charging and discharging process of the battery cells, especially during the continuous high-current discharge process, if it is determined that there is a target battery cell (the target battery cell is one or more of the battery cells), it means that the battery cell cannot tolerate high-speed charging and discharging, so the conduction time corresponding to the target battery cell is shortened and the conduction time of the remaining battery cells is extended to ensure that the total discharge power of the battery pack 1 reaches the target output power. It can be seen that the above setting can protect the target battery cell to the greatest extent, which is beneficial to improve the service life of the entire battery pack 1.

[0093] As a preferred embodiment, determining the on-off time function of the battery cell based on the predicted remaining life includes:

[0094] An evaluation parameter characterizing the degree of aging of the battery cell is determined based on the predicted remaining life of the battery cell and a second preset relationship, where the second preset relationship is:

[0095] ,

[0096] in, To evaluate the parameters, To predict the remaining life, represents the sum of the predicted remaining lifespans corresponding to each battery cell;

[0097] The on-off time function is determined according to the on-off time ratio and the frequency parameter characterizing the on-off switching situation, wherein the on-off time ratio and the frequency parameter are negatively correlated with the evaluation parameter.

[0098] To elaborate, the larger the evaluation parameter is, the higher the aging degree of the battery cell is and the more serious the aging is; the larger the on-off time ratio is, the longer the on-time of the battery cell is; the frequency parameter is a parameter used to characterize the on-off switching situation, the larger the frequency parameter is, the more frequent the on-off switching of the battery cell is; then, for some battery cells with serious aging, the on-off time ratio and frequency parameter should not be too high; as an example, assuming that the current target output power is 60% of the full output power of the battery pack, the on-off time ratio of each battery cell can be close to 60% as a whole, but the actual on-off time ratio of each battery cell is also affected by its corresponding evaluation parameter, for example, if the evaluation parameter is greater than 1, the corresponding on-off time ratio is greater than 60%, and if the evaluation parameter is less than 1, the corresponding on-off time ratio is less than 60%.

[0099] It can be understood that the second preset relationship used to determine the evaluation parameter You can also replace it with the factory life of the battery pack given by the manufacturer.

[0100] It can be seen that the above settings can realize output control of the battery cells in combination with the aging degree of the battery cells, avoid overcharging or over-discharging of severely aged battery cells, avoid causing unnecessary safety problems, and help to improve the service life of the entire battery pack 1.

[0101] The present invention also provides a battery pack charge and discharge balance control system, comprising a control module and a first FPGA2 connected to the control module;

[0102] The first FPGA 2 includes A first gate-controlled switches, the battery pack 1 includes B battery cells connected in series, the pth first gate-controlled switch is connected in parallel with the pth battery cell, A is an integer not less than B, B is an integer greater than 1, 1≤p≤B and p is an integer;

[0103] The control module is used to implement the steps of the battery pack charge and discharge balance control method as described above when executing the computer program.

[0104] For an introduction to the battery pack charge and discharge balance control system provided in the present invention, please refer to the embodiment of the battery pack charge and discharge balance control method described above, which will not be elaborated here.

[0105] As a preferred embodiment, it further comprises a B group of detection modules, and the p-th group of detection modules is connected in parallel with the p-th battery unit;

[0106] The detection module of the pth group includes a voltage detection module 5, a controllable switch module and a current detection module 4, the controllable switch module and the current detection module 4 are connected in series, and the circuit after the series connection is connected in parallel with the voltage detection module 5; the voltage detection module 5, the current detection module 4 and the controllable switch module are all connected to the control module;

[0107] The controllable switch module is used to be turned on and off according to the control instruction of the control module, and the control instruction satisfies that the controllable switch module and the first gate-controlled switch corresponding to the pth battery unit are not turned on at the same time.

[0108] Specifically, the voltage detection module 5 is used to detect the output voltage of the corresponding battery unit, and the current detection module 4 is used to detect the output current of the corresponding battery unit. Figure 6 As shown, in order to ensure safe and reliable operation of the circuit, a detection resistor R2 can also be set, and the detection resistor R2 is connected in series with the current detection module 4 for current limiting; the controllable switch module and its corresponding first gate switch are not turned on at the same time, so as to reliably realize the detection of the output state of the battery cell without affecting the normal operation of the battery cell.

[0109] It is understandable that in actual applications, the first FPGA 2 and the controllable switch module can be coordinated to detect the working status of each battery unit using the detection module in a polling manner.

[0110] As a preferred embodiment, the controllable switch module in the p-th group of detection modules is the p-th second gate-controlled switch in the second FPGA3, and the second FPGA3 includes M second gate-controlled switches, and M is an integer not less than B.

[0111] Specifically, by utilizing the programmable characteristics of FPGA, the second gate switch in the second FPGA3 is used as a controllable switch module, and the second FPGA3 is connected to the control module. Figure 6When the first gate switch 21 in the first FPGA2 is controlled to be turned off, the second gate switch 31 in the second FPGA3 can be controlled to be turned on. At this time, the first battery cell still maintains output, so the output voltage and current of the first battery cell can be monitored; when the first gate switch 21 in the first FPGA2 is controlled to be turned off and the second gate switch 31 in the second FPGA3 is controlled to be turned off, the first battery cell works normally to supply power to the load R1. When the first gate switch 21 in the first FPGA2 is controlled to be turned on and the second gate switch 31 in the second FPGA3 is turned off, the output of the first battery cell is cut off.

[0112] Please refer to Fig. 9 and Fig.10 It is understandable that if Fig.10 As shown, still taking the modular array form of the battery pack 1 as an example, the second FPGA3 performs array encoding according to the actual physical position of the battery pack 1, that is, each second gate switch in the second FPGA3 is set correspondingly, such as the second gate switch in the Io1th row and IoAth column in the second FPGA3 corresponds to the battery cell in the Ath row and the 1st column in the battery pack 1, the second gate switch in the Io1th row and the IoBth column in the second FPGA3 corresponds to the battery cell in the Ath row and the 2nd column in the battery pack 1, and so on, which are not elaborated here; when the second gate switch in the Io1th row and the IoAth column in the second FPGA3 is turned on (such as Fig.10 As shown, the check mark indicates conduction), the first gate switch in the first FPGA2 in the row Io1 and column IoA is turned off (as shown in FIG. Fig. 9 as shown, with a cross indicating shutdown).

[0113] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

[0114] It should also be noted that, in this specification, relational terms such as first, second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not imply any actual relationship or order between these entities or operations.

Claims

1. A battery pack charge and discharge balance control method, characterized in that: A control module applied to a battery pack charge and discharge balancing control system, the battery pack charge and discharge balancing control system further comprising a first FPGA connected to the control module, the first FPGA comprising A first gated switches, the battery pack comprising B battery cells connected in series, the pth first gated switch being connected in parallel with the pth battery cell, A being an integer not less than B, B being an integer greater than 1, 1≤p≤B and p being an integer, the battery pack charge and discharge balancing control method comprising: When the battery pack is to be used to discharge to a load, determining the current remaining maximum capacity of the battery unit; Determining the predicted remaining life of the battery cell according to the remaining maximum capacity and a preset life prediction strategy; Determine an on-off time function of the battery unit based on the predicted remaining life, and control the on and off of a first gate-controlled switch corresponding to the battery unit according to the on-off time function, so that the total discharge power of the battery pack reaches a target output power; During the process of charging or discharging the battery pack, acquiring characteristic information corresponding to the battery cell in the current charging and discharging state, so as to control the corresponding first gate switch to be turned on when it is determined according to the characteristic information that the battery cell is in the state to be stopped from charging and discharging; Determining the predicted remaining life of the battery cell according to the remaining maximum capacity and a preset life prediction strategy includes: Determine the total number of charge and discharge cycles of the battery cell at the remaining maximum capacity according to the corresponding relationship between the preset capacity and the number of cycles of the battery cell; Determine the difference between the total number of charge and discharge cycles that can be cycled and the current number of charge and discharge cycles corresponding to the battery cell as the predicted remaining life of the battery cell; The preset capacity-cycle number correspondence relationship corresponding to the p-th battery cell is determined based on a first preset relationship, and the first preset relationship is: ， in, It represents the maximum remaining capacity of the p-th battery cell after the current k-th charge and discharge cycle. is the first fitting parameter, is the second fitting parameter, and The remaining maximum capacity matrix is ​​determined by least square fitting, wherein the remaining maximum capacity matrix is ​​obtained based on q remaining maximum capacities determined after q charge and discharge cycles within the basic use time, where q is an integer greater than 1.

2. The battery pack charge and discharge balance control method according to claim 1, characterized in that: Also includes: Determine the distance from the last update and Whether the preset cycle number threshold has been exceeded; If so, re-fit the remaining maximum capacity determined within the preset cycle number threshold to determine the and , so as to re-determine the and The preset capacity-cycle number correspondence is updated.

3. The battery pack charge and discharge balance control method according to claim 1, characterized in that: Determining, according to the characteristic information, that the battery unit is in a state to be stopped from charging and discharging, includes: Determine whether any one of the first event, the second event, the third event or the fourth event occurs; the first event is that the charging voltage of the battery cell is greater than a preset saturation voltage, the second event is that the charging current of the battery cell is greater than a preset current threshold, the third event is that the current temperature at the location of the battery cell is greater than a preset temperature threshold, and the fourth event is that the temperature rise rate corresponding to the battery cell exceeds a preset speed threshold; If so, it is determined that the battery unit is in a state to be stopped from charging and discharging; if not, the original state is maintained.

4. The battery pack charge and discharge balance control method according to claim 3, characterized in that: Also includes: Determine whether there is a target battery cell, and the sum of a first historical number of occurrences of the third event and a second historical number of occurrences of the fourth event in the target battery cell is greater than a preset allowable threshold; If so, shorten the conduction time corresponding to the target battery cell and extend the conduction time of the remaining battery cells to ensure that the total discharge power of the battery pack reaches the target output power; if not, do not take any intervention measures.

5. The battery pack charge and discharge balance control method according to any one of claims 1 to 4, characterized in that: Determining an on-off time function of the battery cell based on the predicted remaining life includes: An evaluation parameter characterizing the aging degree of the battery cell is determined based on the predicted remaining life of the battery cell and a second preset relationship, wherein the second preset relationship is: ， in, is the evaluation parameter, is the predicted remaining life, represents the sum of the predicted remaining lifespans corresponding to the battery cells; The on-off time function is determined according to the on-off time ratio and the frequency parameter characterizing the on-off switching situation, wherein the on-off time ratio and the frequency parameter are both negatively correlated with the evaluation parameter.

6. A battery pack charge and discharge balance control system, characterized in that: It includes a control module and a first FPGA connected to the control module; The first FPGA includes A first gate-controlled switches, the battery pack includes B battery cells connected in series, the pth first gate-controlled switch is connected in parallel with the pth battery cell, A is an integer not less than B, B is an integer greater than 1, 1≤p≤B and p is an integer; The control module is used to implement the steps of the battery pack charge and discharge balancing control method as described in any one of claims 1 to 5 when executing a computer program.

7. The battery pack charge and discharge balance control system according to claim 6, characterized in that: Also included is a B group detection module, the p-th group detection module is connected in parallel with the p-th battery unit; The p-th group of detection modules includes a voltage detection module, a controllable switch module and a current detection module, wherein the controllable switch module is connected in series with the current detection module and the series circuit is connected in parallel with the voltage detection module; the voltage detection module, the current detection module and the controllable switch module are all connected to the control module; The controllable switch module is used to be turned on and off according to the control instruction of the control module, and the control instruction satisfies that the controllable switch module and the first gate-controlled switch corresponding to the pth battery unit are not turned on at the same time.

8. The battery pack charge and discharge balance control system according to claim 7, characterized in that: The controllable switch module in the p-th group of detection modules is the p-th second gate-controlled switch in the second FPGA, and the second FPGA includes M second gate-controlled switches and M is an integer not less than B.

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