Power battery active balancing method, system and vehicle

Abstract

The application relates to the technical field of power batteries of vehicles, in particular to a power battery active balancing method and system and a vehicle, wherein the method comprises the following steps: acquiring voltages of each battery monomer of a power battery; determining the battery monomers satisfying an active balancing condition from the voltages of each battery monomer; sequentially turning on the loop of the battery monomers satisfying the active balancing condition and a storage battery; and balancing the voltages of each battery monomer through the charging and discharging between the storage battery and the battery monomers satisfying the active balancing condition. Therefore, the problems that in the related art, when the battery monomers are actively balanced, the control circuit and the control logic are complex, the balancing efficiency is low, and the battery life is short due to poor consistency of the battery monomers are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power battery of vehicle, in particular to a power battery active balancing method, system and vehicle. BACKGROUND

[0002] With the rapid development of new energy automobile industry, the demand for power batteries in the automobile field is increasing; in order to improve the endurance mileage of new energy vehicles, the series and parallel number of automobile power battery pack is increased. Therefore, it is particularly important to increase the service life and maximum available capacity of power battery.

[0003] In related technologies, the consistency of power battery monomer can be maintained by balancing the power battery monomer, wherein the balancing method can be divided into passive balancing and active balancing: passive balancing can discharge the monomer with higher voltage by resistance discharge, release the electric quantity in the form of heat, so as to realize the balancing of the whole power battery pack; active balancing can realize balancing by energy transfer, transfer part of the energy of high energy monomer to the battery with low energy, so as to realize the balancing of the whole power battery pack.

[0004] However, passive balancing is resistance energy consumption balancing, so the current is generally small and the balancing efficiency is low; active balancing involves energy transfer between each monomer of power battery, so it involves more working conditions and parameters, and the logic of balancing control is more complex, and the control cost is also relatively high. SUMMARY

[0005] One of the purposes of the present application is to provide a power battery active balancing method to solve the problems in related technologies that the control circuit and control logic are complex when the internal monomer of the battery is actively balanced, resulting in low balancing efficiency; and because the consistency of the battery monomer is poor, the battery life is short; the second purpose is to provide a power battery active balancing system; the third purpose is to provide a vehicle.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A power battery active balancing method, comprising: acquiring the voltage of each battery monomer of the power battery; determining the battery monomer satisfying the active balancing condition among the battery monomers according to the voltage of each battery monomer; sequentially turning on the loop of the battery monomer satisfying the active balancing condition and the storage battery, and balancing the voltage of each battery monomer through the mutual charging and discharging between the storage battery and the battery monomer satisfying the active balancing condition.

[0008] According to the technical means, the power battery and the storage battery can be integrated in an open manner, the power battery and the storage battery are used to realize active balancing, the integration level of the automobile parts is improved, and the control logic complexity is reduced. In addition, the power battery is used to transfer energy in the active balancing process to realize charging and discharging of the storage battery, the power feeding and overcharging of the storage battery are avoided, the power supply reliability of the storage battery is improved, the system safety is improved, and the actual use requirement is met.

[0009] Further, the balancing of the voltages of the battery cells through the charging and discharging between the storage battery and the battery cell satisfying the active balancing condition comprises: obtaining the current power of the storage battery; if the current power is less than a first preset power, controlling the battery cell satisfying the active balancing condition to charge the storage battery until the voltages of the battery cells are balanced; if the current power is greater than a second preset power, controlling the storage battery to charge the battery cell satisfying the active balancing condition until the voltages of the battery cells are balanced, wherein the second preset power is greater than the first preset power; otherwise, controlling the charging and discharging between the storage battery and the battery cell satisfying the active balancing condition until the voltages of the battery cells are balanced.

[0010] According to the technical means, the first and second preset powers are used to compare the current power of the storage battery to determine the state of the storage battery, different controls of the storage battery are realized, the active balancing process of the storage battery and the power battery is completed, the voltages of the battery cells are balanced, the power feeding and overcharging of the storage battery are avoided, the working robustness of the storage battery and the power battery is improved, and the actual use requirement is met.

[0011] Further, the controlling of the charging and discharging between the storage battery and the battery cell satisfying the active balancing condition comprises: if the current power is greater than or equal to a third preset power, controlling the storage battery to charge the battery cell satisfying the active balancing condition until the balancing of the voltage of one battery cell is completed, wherein the third preset power is less than the second preset power and greater than the first preset power; if the current power is less than the third preset power, controlling the battery cell satisfying the active balancing condition to charge the storage battery until the balancing of the voltage of one battery cell is completed; after the balancing of the voltage of one battery cell is completed, the operation is repeated until the balancing of the voltages of the battery cells is completed.

[0012] According to the technical means, the third preset power is used to determine the power of the storage battery to control the storage battery to further charge or discharge the power battery, the balancing of the voltages of the battery cells is realized, the power supply reliability of the storage battery is improved, and the actual use requirement is met.

[0013] Further, before repeating the above operation until the voltages of the battery cells are balanced, the method comprises: if the current power is less than a first preset power, controlling the battery cell satisfying the active balancing condition to charge the battery until the balancing of the voltage of one battery cell is completed; and if the current power is greater than a second preset power, controlling the battery to charge the battery cell satisfying the active balancing condition until the balancing of the voltage of one battery cell is completed.

[0014] According to the above technical means, the power battery cell with an excessively large voltage difference and the battery cell with a low battery voltage can be sequentially connected to the loop for balancing charging and discharging, so that the corresponding battery cells can be sequentially operated according to the demand size, thereby avoiding redundant blind operation, and the scheme is more intelligent and meets the actual use needs.

[0015] Further, when the battery cell satisfying the active balancing condition is controlled to charge the battery, the battery cell with a voltage greater than the average voltage of the battery cells is used to charge the battery; and when the battery is controlled to charge the battery cell satisfying the active balancing condition, the battery cell with a voltage less than or equal to the average voltage of the battery cells is charged.

[0016] According to the above technical means, the battery cells in need can be operated accordingly, thereby avoiding redundant blind charging and discharging, improving efficiency and integration level, and meeting the actual use needs.

[0017] Further, after the voltages of the battery cells are balanced through the charging and discharging between the battery and the battery cell satisfying the active balancing condition, the method further comprises: if the current power is less than a first preset power, controlling the power battery to charge the battery according to a current difference between the current power and the first preset power; and if the current power is greater than a second preset power, controlling the battery to charge the power battery according to a current difference between the current power and the second preset power, wherein the second preset power is greater than the first preset power.

[0018] According to the above technical means, the capacity required for balancing to a no-power supply risk can be calculated according to the current remaining power of the battery, and the power of the battery is further controlled, thereby reducing the working risk of the battery, improving the reliability of low-voltage power supply of the battery, and meeting the actual use needs.

[0019] Further, the determining the battery monomer satisfying the active equalization condition according to the battery monomer voltage includes: calculating an average voltage according to the battery monomer voltage; if the voltage difference of the battery monomer voltage relative to the average voltage is greater than a preset voltage, the corresponding battery monomer satisfies the active equalization condition.

[0020] According to the above technical means, the embodiment of the application can determine whether the battery monomer satisfies the active equalization condition, so that the blind selection of the battery monomer to cause the charge and discharge redundancy can be avoided; and because the battery monomer satisfying the active equalization condition is screened out to perform the related operation, the battery monomer consistency can be improved, and the actual use needs can be met.

[0021] A power battery active equalization system includes a power battery and a storage battery; a voltage conversion circuit is used to realize the voltage conversion of the power battery and the storage battery; a collection module is used to collect the battery monomer voltage of the power battery; an active equalization module is used to determine the battery monomer satisfying the active equalization condition according to the battery monomer voltage, sequentially turn on the loop of the battery monomer satisfying the active equalization condition and the storage battery, and equalize the battery monomer voltage through the charge and discharge between the storage battery and the battery monomer satisfying the active equalization condition.

[0022] Further, the voltage conversion circuit includes a first sub-circuit, a second sub-circuit and an equalization switch assembly, the first sub-circuit includes a first switch assembly, a second switch assembly and a first voltage converter, and the first sub-circuit is used for the power battery to charge the storage battery; the second sub-circuit includes a third switch assembly, a fourth switch assembly and a second voltage converter, and the second sub-circuit is used for the storage battery to charge the power battery, wherein the equalization switch assembly and the first to fourth switch assemblies are each provided with a plurality of switches, and the positive and negative poles of each power battery are switched through the plurality of switches during the charge and discharge.

[0023] A car includes the power battery active equalization system according to the above embodiment.

[0024] The beneficial effects of the application are as follows:

[0025] (1) The embodiment of the application can open the integration of the power battery and the storage battery, utilize the interaction of the power battery and the storage battery to realize the active equalization, improve the integration level of the automobile parts, and reduce the control logic complexity; and the embodiment of the application can realize the monitoring of the storage battery, utilize the power battery energy transfer in the active equalization process to realize the charge and discharge of the storage battery, effectively avoid the storage battery feeding and overcharging, improve the storage battery power supply reliability, improve the system safety, and meet the actual use needs.

[0026] (2) The embodiment of the present application can compare the current battery capacity with the first and second preset capacities to determine the state of the battery, so as to achieve different control of the battery, and further complete the active balancing process of the battery and the power battery, balance the voltage of each battery cell, avoid the risk of battery feeding or overcharging, improve the working robustness of the battery and the power battery, and meet the actual use needs.

[0027] (3) The embodiment of the present application can use the third preset capacity to determine the battery capacity, so as to control the battery to further charge or discharge the power battery, and further achieve the balancing of the voltage of each battery cell, improve the reliability of the battery power supply, and meet the actual use needs.

[0028] (4) The embodiment of the present application can select the power battery cells with excessive voltage difference and the battery cells with low voltage to be connected to the circuit in turn for balancing charging and discharging. Thus, the corresponding battery cells can be operated in order according to the demand, the redundant blind operation is avoided, the scheme is more intelligent, and the actual use needs are met.

[0029] (5) The embodiment of the present application can perform corresponding operation on the battery cells in need, avoid the redundancy caused by blind charging and discharging, improve the efficiency and integration level, and meet the actual use needs.

[0030] (6) The embodiment of the present application can calculate the capacity required for balancing to the risk-free feeding according to the current remaining capacity of the battery, further control the battery capacity, reduce the working risk of the battery, improve the reliability of the low-voltage power supply of the battery, and meet the actual use needs.

[0031] (7) The embodiment of the present application can determine whether the battery cell meets the active balancing condition, so that the charging and discharging redundancy caused by blind selection of the battery cell can be avoided. Since the battery cell meeting the active balancing condition is selected for related operation, the consistency of the battery cell can be improved, and the actual use needs are met.

[0032] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The flowchart of the power battery active balancing method of the embodiment of the present application;

[0034] Figure 2 The circuit diagram of the power battery active balancing system of the embodiment of the present application;

[0035] Figure 3 The logic schematic block diagram of the active balancing control of the embodiment of the present application;

[0036] Figure 4 FIG. 1 is a schematic diagram of a power battery active balancing system according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] Other advantages and effects of the present application can be easily understood by those skilled in the art from the above description of the embodiments of the present application. The present application can also be implemented or applied in other different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application, but not for limiting the protection scope of the present application.

[0038] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present application, and only the components related to the present application are shown in the diagrams, but not drawn according to the number, shape and size of the components in actual implementation. The shape, number and proportion of each component in actual implementation can be arbitrarily changed, and the layout pattern of the components can also be more complex.

[0039] With the rapid development of the new energy vehicle industry, the demand for power batteries in the automotive field is increasing. In order to improve the cruising range of new energy vehicles, the series and parallel numbers of the automotive power battery pack are also increasing. However, the consistency of the power battery monomer is poor, which shortens the service life and maximum available capacity of the battery with the increase of the charge and discharge number. In addition, the reduction of the service life and maximum available capacity of the power battery also exacerbates the poor consistency of the power battery monomer, forming a vicious cycle, which also increases the amount of power battery scrap year by year. Therefore, it is particularly important to maintain the consistency of the power battery monomer by balancing the power battery monomer to increase the maximum available capacity of the power battery and prolong the service life of the power battery.

[0040] In the related art, the balancing method can be divided into passive balancing and active balancing. The passive balancing can discharge the monomer with higher voltage by the way of resistance discharge, release the electric quantity in the form of heat, so as to realize the balancing of the whole power battery pack, and maintain the voltage of all monomers of the power battery pack in an average range. The active balancing can realize the balancing of the whole power battery pack by transferring part of the energy of the monomer with high energy to the battery with low energy.

[0041] However, the passive balancing and the active balancing still have some defects:

[0042] (1) From the perspective of balance efficiency, active balancing is achieved in the form of energy transfer, and there is no heat generation phenomenon. The balancing current can be large without affecting heat dissipation, and the balancing efficiency is relatively high. Passive balancing is a resistance energy consumption type of balancing. All consumed energy is released in the form of heat. Therefore, a large amount of heat is generated during the balancing process, which causes the temperature of the controller of the power battery to rise. In order to prevent the temperature in the battery pack from being too high and causing a thermal safety accident, the current set by the passive balancing is generally small, and therefore the passive balancing efficiency is low.

[0043] (2) From the perspective of balancing cost, the passive balancing circuit is relatively simple, easier to implement, and has a lower implementation cost. Active balancing involves energy transfer between each single cell of the power battery, involves more working conditions and parameters, and has more complex balancing control logic and relatively high control cost.

[0044] In addition, in addition to the power battery, a 12V storage battery also exists in a new energy vehicle, which can supply power to the low-power system of the vehicle, such as the vehicle control system, the motor control system, and the battery management system. The power loss of the 12V storage battery is inevitable for the vehicle. The power supply of the small battery will cause the vehicle to be unable to start, and the vehicle cannot charge the 12V storage battery, and can only be solved by connecting to other 12V storage batteries or replacing the 12V storage battery. In addition, the power supply of the 12V storage battery will greatly shorten the service life of the small battery and increase the maintenance cost of the vehicle.

[0045] In view of the problems in the prior art that the control circuit and control logic are complex when actively balancing the internal single cells of the battery, the balancing efficiency is low, and the battery life is short due to poor consistency of the battery single cells, the present application can provide a power battery active balancing method, system and vehicle.

[0046] Specifically, Figure 1 A flowchart of a power battery active balancing method provided by an embodiment of the present application is shown in FIG. 1.

[0047] As shown in FIG. 1, the power battery active balancing method includes the following steps: Figure 1

[0048] In step S101, the voltage of each battery single cell of the power battery is acquired.

[0049] It can be understood that the embodiment of the present application can first collect and acquire the voltage of each battery single cell of the power battery. In the embodiment of the present application, the voltage of each battery single cell of the power battery can be acquired in at least one way, such as periodically collecting each battery single cell by using a voltage collection module.

[0050] ​In step S102, the battery monomer satisfying the active equalization condition is determined according to the battery monomer voltage.

[0051] It can be understood that the embodiment of the application can determine whether the battery monomer satisfies the active equalization condition by using the monomer voltage value after obtaining the battery monomer voltage; and the battery capacity can be determined according to the battery monomer voltage to determine whether the battery has a power supply risk and a capacity risk, and when there is no risk, the power battery active equalization mode is entered; wherein the active equalization condition can be set according to the actual situation, and the embodiment of the application can determine the battery monomer satisfying the active equalization condition by using the battery monomer voltage in at least one way.

[0052] As a possible implementation, the battery monomer satisfying the active equalization condition is determined according to the battery monomer voltage, including: calculating the average voltage according to the battery monomer voltage; if the voltage difference of the battery monomer voltage relative to the average voltage is greater than the preset voltage, the corresponding battery monomer satisfies the active equalization condition.

[0053] Wherein, the preset voltage can be set according to the actual situation, which is not limited here.

[0054] It can be understood that the embodiment of the application can sort the collected battery monomer voltage, and calculate the average voltage of each battery monomer and the monomer voltage difference of each battery monomer at this time; if the monomer voltage difference is small at this time and does not exceed the corresponding preset voltage, it can be considered that the active equalization condition is not satisfied; if the voltage difference is greater than the preset voltage, it can be considered that the active equalization condition is satisfied.

[0055] In step S103, the loop of the battery monomer satisfying the active equalization condition and the battery is sequentially turned on, and the battery and the battery monomer satisfying the active equalization condition are mutually charged and discharged to balance the voltage of each battery monomer.

[0056] It can be understood that the power battery pack and the battery in the embodiment of the application are composed of a plurality of battery monomers in series, each battery monomer has a certain monomer voltage, and all are numbered in the order from small to large starting from zero; the embodiment of the application can set that the power battery pack contains N battery monomers in series, and the battery contains M battery monomers in series; after confirming the battery monomer satisfying the equalization condition in the above step S102, the embodiment of the application can sequentially turn on the loop between the battery monomer satisfying the active equalization condition and the battery, so as to balance the voltage of each battery monomer by charging and discharging between them; wherein the embodiment of the application can control the loop of the battery monomer and the battery by at least one way, as follows:

[0057] As a possible implementation, as Figure 2As shown, the embodiment of the present application can set equalization switches to realize the conduction control of the battery monomer and the storage battery loop: on the equalization loop of the power battery and the storage battery, the positive and negative sides of each battery monomer contain an equalization switch, which is controlled by the equalization module to open and close the corresponding monomer, wherein, the power battery pack side has N+1 switches, the storage battery side has M+1 switches, the switch numbering mode is the same as the monomer numbering mode, and the specific switch is integrated in two multiple selection switch modules.

[0058] The embodiment of the present application can set two-way DCDC converters to realize the equalization mode in two opposite directions of charging and discharging, in the process of realizing the equalization of the battery monomer, since the DCDC converter input and output end contains positive and negative poles, in the actual equalization process, the selection of the equalization mode to the equalization loop needs to be further considered, and the problem of positive and negative pole switching caused by the adjacent monomer sharing an equalization switch also needs to be considered.

[0059] Thus, the embodiment of the present application can output the collected voltage information to the active equalization module by using the voltage collection module; the active equalization module calculates the equalization monomer number and the equalization mode of the power battery and the 12V storage battery according to the received voltage information and outputs them to the multiple selection switch module; the multiple selection switch closes the corresponding switch according to the received monomer equalization monomer number and the equalization mode.

[0060] For example, when the multiple selection switch receives the power battery equalization monomer number, the storage battery equalization monomer number and the equalization mode are n, m and equalization discharge respectively, then the n-1 and n number switches on the power battery side, the m-1 and m number switches on the storage battery side and the positive and negative switching switches of the equalization discharge loop are closed, thus the embodiment of the present application can realize the positive and negative switching by using four switches to realize the equalization discharge.

[0061] In the embodiment of the present application, the voltage of each battery monomer is equalized by charging and discharging between the storage battery and the battery monomer meeting the active equalization condition, including: acquiring the current power of the storage battery; if the current power is less than the first preset power, controlling the battery monomer meeting the active equalization condition to charge the storage battery until the voltage of each battery monomer is equalized; if the current power is greater than the second preset power, controlling the storage battery to charge the battery monomer meeting the active equalization condition until the voltage of each battery monomer is equalized, wherein the second preset power is greater than the first preset power; otherwise, controlling the storage battery and the battery monomer meeting the active equalization condition to charge and discharge with each other until the voltage of each battery monomer is equalized.

[0062] Wherein, under the premise of ensuring that the second preset power is greater than the first preset power, the first preset power and the second preset power can be set according to the actual situation, which is not limited here.

[0063] It can be understood that the embodiment of the application can set the first preset electric quantity and the second preset electric quantity, and judge the state of the electric quantity of the battery by comparing the battery with the preset electric quantity. When the electric quantity of the battery is less than the first preset electric quantity, the battery monomer can be controlled to discharge the battery; when the electric quantity of the battery is greater than the second preset electric quantity, the battery can be controlled to charge the battery monomer; until the voltage of each battery monomer is balanced.

[0064] For example, as shown in FIG. 1, the embodiment of the application can judge the capacity of the battery, set the first preset electric quantity as 35% of the full electric quantity of the battery, and set the second preset electric quantity as 85%; when the electric quantity of the battery is lower than 35%, the battery monomer with the excessively high voltage is selected to discharge the battery in turn; when the electric quantity of the battery is higher than 85%, the battery is selected to charge the battery monomer with the lower voltage in turn. Figure 3

[0065] In the embodiment of the application, the control of the charge and discharge between the battery and the battery monomer satisfying the active balancing condition comprises: if the current electric quantity is greater than or equal to the third preset electric quantity, the battery is controlled to charge the battery monomer satisfying the active balancing condition until the balancing of the voltage of one battery monomer is completed, wherein the third preset electric quantity is less than the second preset electric quantity and greater than the first preset electric quantity; if the current electric quantity is less than the third preset electric quantity, the battery monomer satisfying the active balancing condition is controlled to charge the battery until the balancing of the voltage of one battery monomer is completed; after the balancing of the voltage of one battery monomer is completed, the above operation is repeated until the balancing of the voltage of each battery monomer is completed.

[0066] The third preset electric quantity can be set according to the actual situation, and the size relationship of the first, second and third preset electric quantities is that the first preset electric quantity is less than the third preset electric quantity, and the third preset electric quantity is less than the second preset electric quantity.

[0067] It can be understood that the embodiment of the application can detect the capacity of the battery. When the electric quantity of the battery is greater than the third preset electric quantity, it can be considered that the battery monomer needs to be discharged at this time; when the capacity of the battery is less than the third preset electric quantity, it can be considered that the battery monomer needs to discharge the battery at this time.

[0068] For example, as shown in FIG. 1, the embodiment of the application can judge the capacity of the battery, set the first preset electric quantity as 35% of the full electric quantity of the battery, and set the second preset electric quantity as 85%; when the electric quantity of the battery is lower than 35%, the battery monomer with the excessively high voltage is selected to discharge the battery in turn; when the electric quantity of the battery is higher than 85%, the battery is selected to charge the battery monomer with the lower voltage in turn. Figure 3

[0069] ​​In the embodiment of the present application, before the above-mentioned operation is repeated until the voltages of the battery cells are balanced, the operation includes: if the current power is less than the first preset power, controlling the battery cell satisfying the active balancing condition to charge the storage battery until the balancing of the voltage of one battery cell is completed; and if the current power is greater than the second preset power, controlling the storage battery to charge the battery cell satisfying the active balancing condition until the balancing of the voltage of one battery cell is completed.

[0070] It can be understood that the battery cells in the embodiment of the present application can discharge the storage battery in turn or charge the storage battery, that is, after the battery cell completes the operation relative to the storage battery, the voltage balancing of the next battery cell is performed.

[0071] In the embodiment of the present application, when the battery cell satisfying the active balancing condition is controlled to charge the storage battery, the battery cell with the voltage greater than the average voltage of the battery cells is used to charge the storage battery; and when the storage battery is controlled to charge the battery cell satisfying the active balancing condition, the battery cell with the voltage less than or equal to the average voltage of the battery cells is charged.

[0072] In the embodiment of the present application, the average voltage of the battery cells can be the average voltage of all the battery cells, or the average voltage of the battery cells satisfying the active balancing condition, which can be calculated and selected according to actual conditions.

[0073] It can be understood that the average voltage of the battery cells can be calculated in the embodiment of the present application, and when the storage battery needs to be controlled to charge the battery cell, the battery cell with the voltage less than or equal to the average voltage is selected to be charged among the battery cells satisfying the active balancing condition, and the battery cell with the voltage greater than the average voltage is not charged; and when the battery cell needs to be controlled to charge the storage battery, the battery cell with the voltage greater than the average voltage is selected to charge the storage battery among the battery cells satisfying the active balancing condition, and the battery cell with the voltage less than or equal to the average voltage is not operated.

[0074] In the embodiment of the present application, after the voltages of the battery cells are balanced through the charging and discharging between the storage battery and the battery cell satisfying the active balancing condition, the operation further includes: if the current power is less than the first preset power, controlling the power battery to charge the storage battery according to the current and the first preset power; and if the current power is greater than the second preset power, controlling the storage battery to charge the power battery according to the current and the second preset power, wherein the second preset power is greater than the first preset power.

[0075] It can be understood that after the charge and discharge equalization between the battery and the battery monomer meeting the active equalization condition, the application embodiment can further compare the size relationship between the current battery power and the first and second preset power; when the current battery power is less than the first preset power, the difference between the current power and the first preset power is calculated, that is, the required power for equalization to the no-feed risk is calculated according to the current remaining power of the battery, and then the battery is charged according to the difference; when the current battery power is greater than the second preset power, the difference between the current power and the second preset power is calculated, and the battery is charged by using the difference.

[0076] The active equalization method of the power battery of the application will be described below through a specific embodiment. In this embodiment, after the capacity of the battery is judged, there is a risk of overfeeding and overcapacity. The application embodiment takes the battery feeding as an example, and the case of too large battery power is not described in detail; as follows:

[0077] First step, the active equalization module sorts the monomers according to the voltage of the power battery monomers collected by the voltage collection module, and calculates the monomer voltage difference of each monomer of the power battery at this time. If the monomer voltage difference is too small and does not exceed the corresponding threshold value, go to the third step; if the voltage difference is greater than the corresponding threshold value, go to the next step;

[0078] Second step, select the monomers with large voltage difference of the power battery to be connected to the loop in turn with the lower monomers of the 12V battery in turn, start the equalization discharge of the power battery, and after the equalization of the monomers of the power battery is completed, it is necessary to judge again whether the voltage difference is greater than the threshold value. If it still does not meet the condition, the second step is repeated again; otherwise, go to the next step;

[0079] Third step, judge whether the 12V battery has the risk of too low voltage difference. If the battery power has no feeding risk, the process is ended; otherwise, go to the next step;

[0080] Fourth step, the active equalization module calculates the capacity required for equalization to the no-feed risk according to the current remaining power of the battery, and calculates the equalization time and capacity required for equalization to each monomer of the power battery. The corresponding switches of the monomers of the power battery and the 12V battery are controlled in turn, and the battery is charged. After all the monomers are equalized, the process is ended.

[0081] In summary, the active equalization method of the power battery according to the application embodiment has at least the following advantages:

[0082] (1) The embodiment of the present application can open the integration of the power battery and the storage battery, utilize the interaction between the power battery and the storage battery to realize active balancing, improve the integration level of automobile parts, and reduce the complexity of control logic. The embodiment of the present application can realize the monitoring of the storage battery, utilize the energy transfer of the power battery in the active balancing process to realize the charging and discharging of the storage battery, effectively avoid the power feeding and overcharging of the storage battery, improve the reliability of the storage battery power supply, improve the safety of the system, and meet the actual use needs.

[0083] (2) The embodiment of the present application can compare the current power of the storage battery with the first and second preset power, judge the state of the storage battery, realize different control of the storage battery, and then complete the active balancing process of the storage battery and the power battery, balance the voltage of each battery monomer, avoid the power feeding and overcharging risk of the storage battery, improve the working robustness of the storage battery and the power battery, and meet the actual use needs.

[0084] (3) The embodiment of the present application can utilize the third preset power to judge the power of the storage battery, control the storage battery to further charge or discharge the power battery, and then realize the balancing of the voltage of each battery monomer, improve the reliability of the storage battery power supply, and meet the actual use needs.

[0085] (4) The embodiment of the present application can select the monomers with excessive voltage difference of the power battery and the monomers with low voltage of the storage battery to be connected to the loop in turn for balancing charging and discharging. Thus, the corresponding battery monomers can be operated in order according to the demand, the redundancy caused by blind operation can be avoided, the scheme is more intelligent, and the actual use needs can be met.

[0086] (5) The embodiment of the present application can perform corresponding operation on the battery monomers in need, avoid the redundancy caused by blind charging and discharging, improve the efficiency and integration level, meet the actual use needs.

[0087] (6) The embodiment of the present application can calculate the capacity required for balancing to the no power feeding risk according to the current residual power of the storage battery, further control the power of the storage battery, reduce the working risk of the storage battery, improve the reliability of the low-voltage power supply of the storage battery, and meet the actual use needs.

[0088] (7) The embodiment of the present application can determine whether the battery monomers meet the active balancing condition, so that the charging and discharging redundancy caused by blind selection of the battery monomers can be avoided. Because the battery monomers meeting the active balancing condition are selected for related operation, the consistency of the battery monomers can be improved, and the actual use needs can be met.

[0089] Secondly, the power battery active balancing system according to the embodiment of the present application is described with reference to the accompanying drawings.

[0090] Figure 4is a block schematic diagram of a power battery active balancing system according to an embodiment of the present application.

[0091] As shown in Figure 4 , the power battery active balancing system 10 comprises a power battery 100 and a storage battery 200, a voltage conversion circuit 300, an acquisition module 400 and an active balancing module 500.

[0092] The voltage conversion circuit 300 is configured to realize voltage conversion of the power battery 100 and the storage battery 200; the acquisition module 400 is configured to acquire the voltage of each battery cell of the power battery; and the active balancing module 500 is configured to determine, according to the voltage of each battery cell, a battery cell satisfying an active balancing condition among the battery cells, sequentially turn on a loop of the battery cell satisfying the active balancing condition and the storage battery, and balance the voltage of each battery cell through charging and discharging between the storage battery and the battery cell satisfying the active balancing condition.

[0093] In the embodiment of the present application, the voltage conversion circuit 300 comprises a first sub-circuit, a second sub-circuit and an equalization switch assembly, the first sub-circuit comprises a first switch assembly, a second switch assembly and a first voltage converter, the first sub-circuit is configured to charge the storage battery by the power battery; the second sub-circuit comprises a third switch assembly, a fourth switch assembly and a second voltage converter, the second sub-circuit is configured to charge the power battery by the storage battery, wherein the equalization switch assembly and the first to fourth switch assemblies are each provided with a plurality of switches, and the positive and negative poles of each power battery are switched during charging and discharging through the plurality of switches.

[0094] It can be understood that the embodiment of the present application can use the voltage acquisition module as shown in Figure 2 to acquire the single cell voltage and total voltage information of the power battery pack and the 12V storage battery in real time, and output the acquired information to the active balancing module in real time. The active balancing module calculates the power information of the corresponding single cell by judging the voltage information of the power battery pack and the single cell voltage information of the 12V storage battery, determines the corresponding balancing mode and the single cell number that needs to be turned on according to the single cell voltage of the power battery and the power of 12V, and finally controls the corresponding switch in the multi-select switch module to be turned on according to the determined information, so as to realize the balanced charging and discharging of the power battery pack and the 12V storage battery. In addition, an overcurrent protection resistor is connected in series at the output end of each of the two DC / DC converters, which can effectively protect the balancing circuit and prevent the power battery and the 12V storage battery from overcurrent during the active balancing process, so as to prevent the burning of various components on the balancing loop. The power battery and the storage battery each correspond to a voltage acquisition module.

[0095] Specifically, as shown in Figure 2As shown, the whole active balancing system mainly includes a power battery pack (power battery series-parallel connection group), a 12V storage battery pack, a power battery voltage acquisition module, a 12V storage battery voltage acquisition module, an active balancing control module, a charging DC / DC converter, a discharging DC / DC converter, a current-limiting resistor and a multi-path selection switch.

[0096] The adjacent odd-numbered battery monomers are spaced by one battery monomer, and the negative poles of the odd-numbered battery monomers are connected in series with the positive poles of the even-numbered battery monomers in turn; the balancing switch assembly includes power battery balancing switches and storage battery balancing switches, the number of the power battery balancing switches is one more than the number of the battery monomers, and the cost is saved through the shared switches, that is, the negative pole switch of the odd-numbered battery monomers is reused as the positive pole switch of the even-numbered battery monomers, for example, the negative pole switch of the first battery monomer is also the positive pole switch of the second battery monomer. The storage battery balancing switches include switches K51 to K55.

[0097] In the first sub-circuit, the first switch assembly can include switches K11 to K14, one end of K11 and one end of K13 are connected with the positive poles and the negative poles of the odd-numbered battery monomers in the battery monomer sequence, one end of K12 and one end of K14 are connected with the negative poles and the positive poles of the even-numbered battery monomers in the battery monomer sequence; the other end of K11 and the other end of K14 are both connected with one end of the input end of the charging DC / DC converter, the other end of K12 and the other end of K13 are both connected with the other end of the input end of the charging DC / DC converter. The second switch assembly can include switches K21 to K24, one end of K21 and one end of K23 are connected with the positive poles and the negative poles of the odd-numbered battery monomers in the battery monomer sequence of the storage battery, one end of K22 and one end of K24 are connected with the negative poles and the positive poles of the even-numbered battery monomers in the battery monomer sequence of the storage battery; the other end of K21 and the other end of K24 are both connected with one end of the output end of the charging DC / DC converter, the other end of K22 and the other end of K23 are both connected with the other end of the output end of the charging DC / DC converter. In the first sub-circuit, K21 is the output end of the charging DC / DC converter, and is connected in series with an overcurrent protection resistor, which can effectively protect the balancing circuit and prevent the power battery and the 12V storage battery from overcurrent in the active balancing process to cause burning of various components on the balancing circuit.

[0098] For example, if the positive pole switch K61 and the negative pole switch K62 of the first battery monomer are both closed, then K11 and K13 are closed, and K21 and K23 are closed; if the positive pole switch K62 and the negative pole switch K63 of the second battery monomer are both closed, then K12 and K14 are closed.

[0099] In the second sub-circuit, the third switch assembly can include switches K31-K34, one end of K31 and one end of K33 are connected with the positive electrode and the negative electrode of the odd-numbered battery cell in the battery cell sequence, one end of K32 and one end of K34 are connected with the negative electrode and the positive electrode of the even-numbered battery cell in the battery cell sequence; the other end of K31 and the other end of K34 are both connected with one end of the input end of the discharging DC / DC converter, the other end of K32 and the other end of K33 are both connected with the other end of the input end of the discharging DC / DC converter. The fourth switch assembly can include switches K41-K44, one end of K41 and one end of K43 are connected with the positive electrode and the negative electrode of the odd-numbered battery cell in the battery cell sequence of the storage battery, one end of K42 and one end of K44 are connected with the negative electrode and the positive electrode of the even-numbered battery cell in the battery cell sequence of the storage battery; the other end of K41 and the other end of K44 are both connected with one end of the input end of the discharging DC / DC converter, the other end of K42 and the other end of K43 are both connected with the other end of the input end of the discharging DC / DC converter. In the second sub-circuit, K41 is the output end of the discharging DC / DC, and is connected in series with an overcurrent protection resistor, which can effectively protect the equalization circuit and prevent overcurrent from occurring in the active equalization process of the power battery and the 12V storage battery, so as to cause burning of various components on the equalization circuit.

[0100] For example, if the positive electrode switch K66 and the negative electrode switch K67 of the fifth battery cell are both closed, K31 and K33 are closed, and K41 and K43 are closed; if the positive electrode switch K67 and the negative electrode switch K68 of the sixth battery cell are both closed, K32 and K34 are closed, and K42 and K44 are closed.

[0101] It should be noted that the foregoing description of the embodiment of the active equalization method of the power battery also applies to the active equalization system of the power battery of the embodiment, which will not be described here again.

[0102] The active equalization system of the power battery according to the embodiment of the present application can integrally open the power battery and the storage battery, realize active equalization by the interaction between the power battery and the storage battery, improve the integration level of automobile parts, and reduce the complexity of the control logic; and the embodiment of the present application can realize monitoring of the storage battery, and realize charging and discharging of the storage battery by the power battery in the active equalization process, effectively avoid the conditions of power feeding and overcharging of the storage battery, improve the reliability of power supply of the storage battery, improve the safety of the system, and meet the actual use needs.

[0103] The embodiment of the present application also provides a vehicle comprising the active equalization system of the power battery according to the above-described embodiment.

[0104] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms is not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or N embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0105] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "N" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0106] Any process or method descriptions in flow charts or otherwise described herein can be understood as representing code modules, segments, or portions of code that include one or more executable instructions for implementing the specified logical functions or steps, and the preferred embodiments of the present application include additional implementations in which the functions described with the flow charts are implemented with different orderings of the steps, overlapping or entirely separate steps performed in parallel, or with the functions being performed at different times, as will be appreciated by those skilled in the art.

[0107] It should be understood that portions of the present application can be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the N steps or methods can be implemented with software or firmware stored in a memory and executed by a suitable instruction execution system. As in another embodiment, if implemented with hardware, any of the following technologies known in the art or their combinations can be used: discrete logic circuit with logic gate circuit for implementing logical functions on data signals, application specific integrated circuit with suitable combination logic gate circuit, programmable gate array, field programmable gate array, etc.

[0108] Those skilled in the art of the present technology can understand that all or part of the steps carried out by the above-described embodiment method can be completed by a program instructing the relevant hardware, and the program can be stored in a computer readable storage medium. The program, when executed, includes one or a combination of steps of the method embodiment.

[0109] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that changes, modifications, substitutions and variations can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A method for active balancing of power batteries, characterized in that, Includes the following steps: Obtain the voltage of each individual cell in the power battery; The battery cells that meet the active balancing conditions are determined based on the voltage of each battery cell. The circuits of the battery cells that meet the active balancing conditions and the storage battery are sequentially connected, and the voltage of each battery cell is balanced by the charging and discharging of the storage battery and the battery cells that meet the active balancing conditions. The step of balancing the voltage of each battery cell by charging and discharging the battery and the battery cells that meet the active balancing conditions includes: obtaining the current charge level of the battery; if the current charge level is less than a first preset charge level, controlling the battery cells that meet the active balancing conditions to charge the battery until the voltage of each battery cell is balanced; if the current charge level is greater than a second preset charge level, controlling the battery to charge the battery cells that meet the active balancing conditions until the voltage of each battery cell is balanced, wherein the second preset charge level is greater than the first preset charge level; otherwise, controlling the charging and discharging of the battery and the battery cells that meet the active balancing conditions until the voltage of each battery cell is balanced. The charging and discharging between the controlled storage battery and the individual battery cells that meet the active balancing conditions includes: If the current power level is greater than or equal to the third preset power level, the battery is controlled to charge the battery cells that meet the active balancing conditions until the voltage of one battery cell is balanced. The third preset power level is less than the second preset power level and greater than the first preset power level. If the current power level is less than the third preset power level, the battery cells that meet the active balancing conditions are controlled to charge the battery until the voltage of one battery cell is balanced. After the voltage of one battery cell is equalized, the operation is repeated until the voltage of all battery cells is equalized. Before repeating the above operation until the voltage of each battery cell is balanced, the operation includes: if the current power level is less than a first preset power level, controlling the battery cell that meets the active balancing condition to charge the battery until the voltage of one battery cell is balanced. If the current battery level is greater than the second preset battery level, the battery is controlled to charge the battery cells that meet the active balancing conditions until the voltage of a battery cell is balanced.

2. The active balancing method for power batteries according to claim 1, characterized in that, When controlling the battery cells that meet the active balancing conditions to charge the battery, the battery is charged using the battery cells whose voltage is greater than the average voltage of the battery cells that meet the active balancing conditions; when controlling the battery to charge the battery cells that meet the active balancing conditions, the battery cells whose voltage is less than or equal to the average voltage of the battery cells that meet the active balancing conditions are charged.

3. The active balancing method for power batteries according to claim 1, characterized in that, After equalizing the voltage of each battery cell through charging and discharging between the battery and the battery cells that meet the active equalization conditions, the method further includes: If the current power level is less than the first preset power level, the power battery is controlled to charge the storage battery according to the current difference between the current power level and the first preset power level. If the current power level is greater than the second preset power level, the storage battery is controlled to charge the power battery according to the current difference between the current power level and the second preset power level, wherein the second preset power level is greater than the first preset power level.

4. The active balancing method for power batteries according to claim 1, characterized in that, The step of determining which battery cells meet the active balancing conditions based on the voltage of each battery cell includes: Calculate the average voltage based on the voltage of each individual battery cell; If the voltage difference between the individual battery cell voltage and the average voltage is greater than a preset voltage, then the corresponding individual battery cell meets the active balancing condition.

5. A power battery active balancing system, characterized in that, For implementing the active balancing method for power batteries as described in claim 1, the active balancing system for power batteries includes: Power batteries and storage batteries; A voltage conversion circuit is used to realize voltage conversion between the power battery and the storage battery; The acquisition module is used to acquire the voltage of each individual cell of the power battery; An active balancing module is used to determine which battery cells meet the active balancing conditions based on the voltage of each battery cell, sequentially connect the circuit between the battery cells that meet the active balancing conditions and the storage battery, and balance the voltage of each battery cell through the charging and discharging of the storage battery and the battery cells that meet the active balancing conditions.

6. The active balancing system for power batteries according to claim 5, characterized in that, The voltage conversion circuit includes: The system comprises a first sub-circuit, a second sub-circuit, and an equalization switch assembly. The first sub-circuit includes a first switch assembly, a second switch assembly, and a first voltage converter. The first sub-circuit is used by the power battery to charge the storage battery. The second sub-circuit includes a third switch assembly, a fourth switch assembly, and a second voltage converter. The second sub-circuit is used by the storage battery to charge the power battery. The equalization switch assembly and the first to fourth switch assemblies are each equipped with multiple switches, which enable the switching of the positive and negative terminals of each power battery during charging and discharging.

7. A vehicle, characterized in that, Including the active balancing system for power batteries as described in claim 5 or 6.

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