An equalization controller, equalization control method and electric vehicle of a power battery

Abstract

The application provides a power battery equalization controller, an equalization control method and an electric vehicle, and relates to the technical field of new energy batteries.The controller comprises an equalization control board, a plurality of equalization modules and a processor.The equalization control board comprises a plurality of equalization modules, and each equalization module comprises a plurality of equalization channels.The processor is electrically connected to each equalization module to control the conduction of each equalization channel.Each equalization channel is electrically connected to one battery cell in a battery module.The processor is used to calculate the maximum number of conduction of the equalization module according to the temperature constraint of the equalization module.The processor is also used to determine the conduction state of the equalization channel in each equalization module according to the maximum number of conduction and the required discharge capacity of each battery cell.The application can improve the equalization efficiency of the power battery and shorten the equalization time.

Description

Technical Field

[0001] This invention relates to the field of new energy battery technology, and in particular to a power battery equalization controller, equalization control method, and electric vehicle. Background Technology

[0002] With the increasing popularity of electric vehicles, the capacity and lifespan of power batteries are receiving more and more attention. Battery balancing controllers eliminate cell inconsistencies through discharge, thereby improving the overall capacity and lifespan of the battery. However, due to the relatively small discharge current and the ever-increasing capacity of power batteries, balancing efficiency has become a major challenge. Currently, traditional power battery controllers use a greedy rule to determine the switching of balancing channels. When considering the hardware constraints of the battery balancing controller, problems such as low balancing efficiency and long processing time exist. Therefore, improvements are needed. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a power battery equalization controller, equalization control method and electric vehicle, so as to solve the problems of low equalization efficiency and long time consumption of power battery controllers in the prior art.

[0004] To achieve the above and other related objectives, the present invention provides a power battery equalization controller, comprising:

[0005] An equalization control board includes multiple equalization modules, each of which includes multiple equalization channels; and

[0006] A processor is electrically connected to each of the equalization modules to control the activation of each of the equalization channels;

[0007] Each of the equalization channels is electrically connected to one cell in the battery module;

[0008] The processor is used to calculate the maximum conduction number of the equalization module based on the temperature constraint of the equalization module;

[0009] The processor is also used to determine the conduction state of the equalization channel in each equalization module based on the maximum number of conductions and the required discharge amount of each cell.

[0010] In one embodiment of the present invention, the equalization channel includes:

[0011] At least two balancing resistors are electrically connected to the positive and negative terminals of the battery cell, respectively; and

[0012] The switching transistor is electrically connected between the two equalizing resistors;

[0013] The processor is electrically connected to the control terminal of the switching transistor.

[0014] In one embodiment of the present invention, two adjacent equalization channels share one equalization resistor.

[0015] In one embodiment of the present invention, the equalization channel further includes a data interface, which is externally connected to a sampling chip to obtain the output voltage and / or output current of each of the battery cells.

[0016] In one embodiment of the present invention, the equalization module further includes a temperature sensor for detecting the temperature of each of the equalization channels.

[0017] In one embodiment of the present invention, the maximum number of conductions n of the equalization channel is... c Satisfy the following formula:

[0018]

[0019] Where round() represents the rounding operation, k represents the thermal convection coefficient, A represents the thermal convection area, and T max T represents the temperature constraint threshold. env The ambient temperature is represented by I, the discharge current is represented by R, and the resistance value of the equalization resistor is represented by r. c This indicates the duty cycle of the equalization channel.

[0020] In one embodiment of the present invention, the processor is further configured to:

[0021] The required discharge amount of each of the battery cells is obtained, and the required discharge amounts of two adjacent battery cells are summed to generate multiple power sum values;

[0022] The summation of the electrical quantities is iterated from largest to smallest, and the conduction state of each equalization channel is determined sequentially based on the maximum conduction count.

[0023] The present invention also provides a power battery balancing control method, applied to the power battery balancing controller as described above, the balancing control method comprising:

[0024] Based on the temperature constraint of the equalization module, calculate the maximum conduction number of the equalization module; and

[0025] The conduction state of the equalization channel in each equalization module is determined based on the maximum number of conductions and the required discharge amount of each cell.

[0026] In one embodiment of the present invention, after determining the conduction state of each equalization channel based on the required discharge amount of each cell and the maximum conduction number, the method further includes:

[0027] The maximum conduction count is calibrated under different ambient temperatures to generate the maximum conduction count of the equalization module under any ambient temperature.

[0028] The present invention also provides an electric vehicle, including a power battery equalization controller as described in any of the above claims.

[0029] As described above, the equalization controller, equalization control method, and electric vehicle of the present invention have the following beneficial effects: the present invention can adopt the optimal discharge strategy under different ambient temperatures and different initial charge levels, which can improve the equalization efficiency of the power battery and shorten the equalization time. Attached Figure Description

[0030] Figure 1 The diagram shown is a structural schematic of a power battery equalization controller provided by the present invention.

[0031] Figure 2 The diagram shown is a circuit diagram of the equalization channel in one embodiment of the present invention.

[0032] Figure 3 The diagram shown is a flowchart illustrating a power battery balancing control method provided by the present invention.

[0033] Figure 4 Displayed as Figure 3 A flowchart illustrating a specific implementation of step S200.

[0034] Figure 5 The diagram shown is a schematic representation of an electric vehicle provided by the present invention.

[0035] Component designation explanation

[0036] 100. Equalization control board; 110. Equalization module; 111. Equalization channel; 1111. Equalization resistor; 1112. Switching transistor; 1113. Data interface; 112. Temperature sensor; 113. Data interface;

[0037] 200. Processor;

[0038] 300, battery cell;

[0039] 400. Electric vehicles; 401. Battery management system; 402. Power battery; 403. Vehicle control system. Detailed Implementation

[0040] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0041] Please see Figures 1 to 5 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness or purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0042] It should be noted that a power battery may include multiple battery modules, each of which can consist of several cells connected in series. Due to differences in manufacturing and usage processes, the cells within a battery module exhibit inconsistencies, primarily in cell capacity, internal resistance, self-discharge rate, and charge / discharge efficiency. These inconsistencies will be transmitted to the power battery pack, leading to a loss of capacity and consequently a decline in lifespan and performance. Therefore, cell equalization is necessary.

[0043] Please see Figures 1 to 5 This invention provides a power battery equalization controller, equalization control method, and electric vehicle, relating to the field of new energy battery technology. This invention can be specifically applied to the equalization processing of power batteries. Employing a near-optimal strategy, this invention can improve equalization efficiency and shorten equalization time while meeting hardware constraints. Detailed descriptions will follow through specific embodiments.

[0044] Please see Figure 1 As shown, Figure 1The diagram shown illustrates the structure of a power battery equalization controller provided by this invention. In one embodiment, the power battery equalization controller may include an equalization control board 100 and a processor 200. The equalization control board may include multiple equalization modules 110. Each equalization module may include multiple equalization channels 111. Each equalization channel 111 is electrically connected to a cell 300 in the battery module, meaning there is a one-to-one correspondence between equalization channels 111 and cell 300. Each equalization channel 111 and a cell 300 can form an equalization loop; when the loop is open, the cell 300 can discharge. The processor 200 is electrically connected to each equalization module 110 and can be used to control the conduction state of each equalization channel 111, i.e., whether each equalization channel 111 is turned on. In this embodiment, the processor 200 employs an approximately optimal strategy for control. First, it calculates the maximum number of equalization channels 111 that are on based on temperature constraints; then, it determines the conduction state of each equalization channel 111 based on the required discharge amount of each cell 300 and the maximum number of equalization channels 111 that are on.

[0045] Please see Figure 2 As shown, Figure 2 This diagram illustrates a circuit of an equalization channel 111 according to an embodiment of the present invention. In one embodiment, the equalization channel 111 may include equalization resistors 1111, a switching transistor 1112, and a data interface 1113. The equalization resistors 1111 may be at least two, and may be electrically connected to the positive and negative terminals of the corresponding battery cell 300. In this embodiment, the resistance values ​​of the equalization resistors 1111 at different locations may be the same. The switching transistor 1112 may be an NMOS (N-Metal-Oxide-Semiconductor) transistor, and may be electrically connected between two equalization resistors 1111 to form an equalization loop. The processor 200 may be electrically connected to the control terminal of the switching transistor 1112. Therefore, the processor 200 can control the conduction state of the equalization loop by controlling the on / off state of the switching transistor 1112. The data interface 1113 may be multiple, and may be electrically connected between the equalization resistors 1111 and the switching transistor 1112. Data interface 1113 can be connected to an external sampling chip to obtain the output voltage and / or output current of each cell 300.

[0046] In one embodiment of the present invention, a battery module may include multiple cells connected in series, for example, the number of cells may be 64. The cells in the battery module may be divided into multiple isomorphic control regions, for example, 64 cells may be divided into 4 control regions, then each control region may include 16 cells, that is, 16 equalization channels are required. Therefore, one equalization module 110 may correspond to one control region, and one equalization channel 111 may correspond to one cell 300.

[0047] Please see Figure 1 As shown, in one embodiment of the present invention, each equalization module 110 may have 16 equalization channels 111. The number on each equalization channel 111 may represent the index of its equalization resistor 1111. For example, the Nth equalization channel 111 may use the (N-1)th column equalization resistor 1111 and the Nth column equalization resistor 1111. The 16 equalization channels 111 may be divided into two groups and disposed on the front and back sides of the equalization module 110. In this embodiment, equalization channels 4-7 and 12-16 may be located on the front side of the equalization module 110, and equalization channels 0-3 and 8-11 may be located on the back side of the equalization module 110.

[0048] Please see Figure 2 As shown, in one embodiment of the present invention, when the first equalization channel 111 is turned on, the battery cell 300 connected to it can discharge through the 0th column equalization resistor 1111 and the 1st column equalization resistor 1111, and the two sets of resistors are connected in series. According to the circuit design of the equalization channel 111, the activation of the equalization channel 111 is limited because two adjacent equalization channels 111 share the same equalization resistor 1111. For example, the first equalization channel 111 and the second equalization channel 111 share the 1st column equalization resistor 1111. Therefore, the present invention sets channel constraints, that is, hardware restrictions on simultaneously opening two adjacent equalization channels 111.

[0049] Please see Figure 1 As shown, in one embodiment of the present invention, the equalization module 110 further includes at least two temperature sensors 112 to ensure engineering redundancy. The two temperature sensors 112 can be respectively disposed at the same position on the front and back sides of the equalization module 110. When the temperature sensor 112 senses that the hardware temperature of the equalization module 110 exceeds the shutdown temperature threshold, it can feed the temperature information back to the processor 200. At this time, the processor 200 will shut down all equalization channels 111 of the equalization module 110 and keep equalization stopped. When the hardware temperature of the equalization module 110 drops to the activation temperature threshold, equalization will be restarted. Therefore, the present invention sets a temperature constraint, that is, equalization will stop when the hardware temperature exceeds the set temperature. In this embodiment, the shutdown temperature threshold can be set in the range of 100℃ to 110℃, and the activation temperature threshold can be set in the range of 85℃ to 95℃.

[0050] In one embodiment of the present invention, the equalization controller of the power battery adopts an approximately optimal strategy to control the conduction state of each equalization channel 111. As described above, the processor 200 controls the conduction of the equalization channel 111 to satisfy channel constraints and temperature constraints. The channel constraints represent that the hardware of the present invention restricts two adjacent equalization channels 111 from being turned on simultaneously, and the temperature constraints represent that all equalization channels 111 will be turned off when the hardware temperature exceeds the shutdown temperature threshold.

[0051] In one embodiment of the present invention, to meet temperature constraints, an approximate optimal solution for the discharge of a single battery cell can first be obtained to determine the fastest discharge strategy for a single battery cell. In this embodiment, heat conduction between multiple equalization channels 111 during the discharge of multiple battery cells 300 is ignored, and the two columns of equalization resistors 1111 in a single equalization channel 111 and the control board nearby are approximated as a single heat capacity, defined as the equivalent heat capacity of the equalization channel. The temperature change of this equivalent heat capacity of the equalization channel can satisfy the following formula:

[0052]

[0053] Where t represents the discharge time, i.e., the time during which the equalization channel 111 is turned on; I represents the discharge current when the equalization channel 111 is turned on; r(t) represents the closing and opening of the equalization channel 111, r(t) = 0 or 1. Within one control cycle, r(t) can be represented by the duty cycle, where r(t) ∈ [0, r max R represents the resistance of the equalization resistor 1111; k represents the thermal convection coefficient; A represents the thermal convection area; T(t) represents the temperature of the equivalent heat capacity of the equalization channel, which is also the temperature measured by the temperature sensor 112; T env T represents ambient temperature. env However, a constant temperature, such as the constant temperature of a battery pack; c represents specific heat capacity; m represents the mass of the heat capacity.

[0054] In this embodiment, assuming the discharge starts at t=0 and ends at t=t′, the discharge charge q of a single cell can satisfy the following formula:

[0055]

[0056] Integrating the temperature change formula of the equilibrium channel 111 over time and combining it with the above equation, we can obtain:

[0057]

[0058] It should be noted that the strategy that maximizes the discharge capacity of a single cell during the time interval from 0 to t′ is the fastest discharge strategy. As shown in the above formula, the discharge capacity q depends on the temperature T(t) and the final temperature T(t′). Therefore, when the temperature T(t) is at its maximum value at any time t, the discharge capacity q is also at its maximum value, which is the fastest discharge strategy.

[0059] In this embodiment, it is assumed that the conduction state of the equalization channel 111 is constant within the minimum control period, that is, the duty cycle is constant. At this time, r(t) = r. Solving the differential equation analytically, we know that the temperature T(t) satisfies the following formula:

[0060]

[0061] According to the above formula, the discharge strategy is the duty cycle r. (It is known that...) And when t>0, In the above formula, T(0) refers to the initial temperature within a certain minimum control cycle, not the initial temperature at the very beginning of the discharge. Therefore, depending on the situation of T(0), the following two cases can be included: First, when T(0) of two different strategies is the same, if the duty cycle r of a certain strategy is the largest, then the T(t) of that strategy is the largest; Second, when the T(0) of a certain strategy is the largest among all strategies, then as long as the largest duty cycle r is used based on this strategy, then T(t) will still be the largest. Therefore, as long as the largest duty cycle r = r is used in each minimum control cycle, max If the temperature T(t) is at its maximum value at any time t, then the above strategy is the fastest discharge strategy.

[0062] It should be noted that when the hardware temperature reaches the shutdown temperature threshold T... max If the temperature continues to rise, a temperature constraint will be triggered. The processor 200 will shut down the equalization channel 111 and keep equalization stopped until the hardware temperature drops to the activation temperature threshold, at which point equalization will restart. In this embodiment, the shutdown temperature threshold T... max =105℃, activation temperature threshold T rs =95℃. Therefore, T(t) cannot remain at its maximum value T indefinitely. max Therefore, when the temperature T(t) reaches T max At 105℃, in order to keep the temperature consistently at T max This allows the duty cycle r to satisfy the following formula:

[0063]

[0064] r in the above formula c ∈[0,r max That is, to keep the temperature T(t) at T maxThe required duty cycle. From this, we can derive the fastest discharge strategy for a single cell: when T(t) <T max At that time, r(t) = r max When T(t) = T max At that time, r(t) = r c The fastest discharge strategy ensures that the temperature T(t) is at its maximum value at any time t.

[0065] Furthermore, when all cells in a control area need to be discharged and balanced, the maximum conduction number of the balancing channels 111 in the balancing module 110 needs to be calculated. Specifically, the heat capacity of all balancing channels 111 in a balancing module 110 is approximately equivalent to one heat capacity, and defined as the equivalent heat capacity of the balancing module. The temperature change of the equivalent heat capacity of the balancing module can satisfy the following formula:

[0066]

[0067] Where r′(t) represents the equivalent duty cycle, r′(t)=r(t)n B (t), n B (t)∈[0,n max [(t)] represents the total number of equalization modules 110 that are turned on within the equalization module 110. I represents the discharge current when the equalization channel 111 is turned on; R represents the resistance value of the equalization resistor 1111; k represents the thermal convection coefficient; A represents the thermal convection area; T(t) represents the temperature of the equivalent heat capacity of the equalization module, which is also the temperature measured by the temperature sensor 112; T env Here, c represents the ambient temperature; c represents the specific heat capacity; and m represents the mass of the heat capacity. Based on the above channel constraints, the hardware of this invention limits the simultaneous opening of two adjacent equalization channels 111. Therefore, at any given time, the maximum number of equalization channels 111 that can be opened is n. max (t) is equal to half the total number of equalization channels 111 in equalization module 110. For example, when the total number of equalization modules 110 is 16, n max (t) = 8. Since the equalization channel 111 of cell 300, which has already finished discharging, will not be turned on, the maximum number of cells turned on is n. max (t) will change with time, therefore r′(t)∈[0,r max n max (t)].

[0068] In this embodiment, the discharge problem of all cells within a control region is mathematically equivalent to that of a single cell. Therefore, the optimal strategy for the discharge problem of a control region is:

[0069] When T(t) <T max At that time, r′(t)=r max n max(t);

[0070] When T(t) = T max hour,

[0071] In this embodiment, the maximum number of conductions n c The following formula can be satisfied:

[0072]

[0073] Where round is the integer operation, r c ≠0.

[0074] In this embodiment, the duty cycle r c The following formula can be satisfied:

[0075]

[0076] Where, n c ∈[1,n max (t)].

[0077] Therefore, in one embodiment of the present invention, when the entire battery module needs to undergo discharge equalization, the equalization channels 111 of multiple equalization modules 110 can be equivalent to one heat capacity. The temperature T(t) of this equivalent heat capacity is taken as the highest value of the temperature sensor in each equalization module 110 at time t. B (t) represents the total number of channels open in each equalization module 110. Based on n B The maximum number of channels turned on in each equalization module 110 is allocated based on the sum of the required discharge quantities for each control region (t) and the quantity of discharge demanded in each control region. The control region with a larger required discharge quantity will have a larger maximum number of channels turned on in its corresponding equalization module 110.

[0078] It should be noted that when the hardware, power requirements, and control strategies of each balancing module 110 are similar, the heat capacity temperature of each balancing module is also similar, resulting in minimal heat conduction. Therefore, when considering the discharge of all cells 300 in the battery module simultaneously, it can be approximated that no heat conduction occurs between the balancing modules.

[0079] Furthermore, based on the maximum number of conductions in the equalization module 100 and the required discharge amount of each cell within the corresponding control area, the conduction state of each equalization channel 111 is determined. Specifically, after determining the maximum number n of conductions in the equalization channel 111 of the equalization module 100... c Next, it is necessary to decide which channels to open. Due to hardware limitations, two adjacent equalization channels 111 can be opened simultaneously. Therefore, the theoretically shortest discharge time depends on the maximum sum of the required discharge amounts of two adjacent cells 300. That is, the theoretically shortest discharge time satisfies the following formula:

[0080]

[0081] Where, q N This represents the required discharge amount of cell 300 corresponding to the Nth equalization channel 111, with `max` indicating the maximum value. The actual discharge time is greater than or equal to `t`. min Therefore, the required discharge quantities of the two adjacent equalization channels 111 at the current moment are summed, and the sums are iterated in descending order. Then, in each summation, it is determined whether the equalization channel 111 with the larger required discharge quantity can be opened. If it can, it is confirmed to be open; otherwise, it is determined whether the equalization channel 111 with the smaller required discharge quantity can be opened. If it can, it is confirmed to be open. This process is repeated to determine the next set of equalization channels 111 for summation, until n equalization channels 111 are opened. c The process involves summing the values ​​of each channel or all groups. The conditions for determining whether equalization channel 111 can be opened include channel constraints and whether the equalization channel 111 has completed the required discharge.

[0082] In one embodiment of the present invention, the cells can be sorted according to their required discharge capacity, and then iterated in descending order. If the equalization channel 111 corresponding to the cell 300 can be opened, it is confirmed to be open; if it cannot be opened, the process continues to check the next equalization channel 111 until n equalization channels are opened. c One channel or all channels have been traversed. The conditions for determining whether the equalization channel 111 can be opened include channel constraints and whether the equalization channel 111 has completed the required discharge amount.

[0083] Please see Figure 3 As shown, Figure 3 The diagram shown illustrates a process flow of a power battery balancing control method provided by the present invention. This method can be applied to the balancing controller of the aforementioned power battery and may include the following steps:

[0084] Step S100: Calculate the maximum conduction number of the equalization module based on the temperature constraint of the equalization module;

[0085] Step S200: Determine the conduction state of the equalization channel in each equalization module based on the maximum number of conductions and the required discharge amount of each cell.

[0086] In one embodiment of the present invention, when step S100 is executed, the maximum conduction count of the equalization module is calculated based on the temperature constraint of the equalization module. Specifically, the equalization control board may include multiple equalization modules 110. Each equalization module may include multiple equalization channels 111. Each equalization channel 111 may be electrically connected to a cell 300 in the battery module. When all cells in a control area need to discharge, the maximum conduction count of the equalization channels 111 in the equalization module 110 needs to be calculated. Specifically, the heat capacity of all equalization channels 111 in an equalization module 110 is approximately equivalent to one heat capacity and defined as the equivalent heat capacity of the equalization module. The temperature change of the equivalent heat capacity of the equalization module can satisfy the following formula:

[0087]

[0088] Where r′(t) represents the equivalent duty cycle, r′(t)=r(t)n B (t), n B (t)∈[0,n max [(t)] represents the total number of equalization modules 110 that are turned on within the equalization module 110. I represents the discharge current when the equalization channel 111 is turned on; R represents the resistance value of the equalization resistor 1111; k represents the thermal convection coefficient; A represents the thermal convection area; T(t) represents the temperature of the equivalent heat capacity of the equalization module, which is also the temperature measured by the temperature sensor 112; T env Here, c represents the ambient temperature; c represents the specific heat capacity; and m represents the mass of the heat capacity. Based on the above channel constraints, the hardware of this invention limits the simultaneous opening of two adjacent equalization channels 111. Therefore, at any given time, the maximum number of equalization channels 111 that can be opened is n. max (t) is equal to half the total number of equalization channels 111 in equalization module 110. For example, when the total number of equalization modules 110 is 16, n max (t) = 8. Since the equalization channel 111 of cell 300, which has already finished discharging, will not be turned on, the maximum number of cells turned on is n. max (t) will change with time, therefore r′(t)∈[0,r max n max (t)].

[0089] In this embodiment, the discharge problem of all cells within a control region is mathematically equivalent to that of a single cell. Therefore, the optimal strategy for the discharge problem of a control region is:

[0090] When T(t) <T max At that time, r′(t)=r max n max (t);

[0091] When T(t) = T max hour,

[0092] In this embodiment, the maximum number of conductions n c The following formula can be satisfied:

[0093]

[0094] Where round is the integer operation, r c ≠0.

[0095] In this embodiment, the duty cycle r c The following formula can be satisfied:

[0096]

[0097] Where, n c ∈[1,n max (t)].

[0098] Please see Figure 4 As shown, Figure 4 Displayed as Figure 3 A schematic flowchart of a specific implementation of step S200 may include the following steps:

[0099] Step S201: Obtain the required discharge amount of each cell, and sum the required discharge amounts of two adjacent cells to generate multiple power sum values;

[0100] Step S202: Iterate through multiple summation values ​​of electrical charge from largest to smallest, and determine the conduction state of each equalization channel based on the maximum conduction count.

[0101] In one embodiment of the present invention, when step S201 is executed, the required discharge amount of each battery cell is obtained, and the required discharge amounts of two adjacent battery cells are summed to generate multiple power sum values. Specifically, after determining the maximum number of conduction channels n in the equalization module 100, the required discharge amount of each battery cell is obtained. c Next, it is necessary to decide which channels to open. Due to hardware limitations, two adjacent equalization channels 111 can be opened simultaneously. Therefore, the theoretically shortest discharge time depends on the maximum sum of the required discharge amounts of two adjacent cells 300. That is, the theoretically shortest discharge time satisfies the following formula:

[0102]

[0103] Where, q N This represents the required discharge amount of cell 300 corresponding to the Nth equalization channel 111, with `max` indicating the maximum value. The actual discharge time is greater than or equal to `t`. minTherefore, the required discharge quantities of the two adjacent equalization channels 111 at the current moment are summed, and the summed values ​​of the generated quantities are confirmed sequentially.

[0104] In one embodiment of the present invention, when step S202 is executed, multiple summation values ​​of electrical charge are traversed sequentially from largest to smallest, and the conduction state of each equalization channel is determined sequentially based on the maximum conduction count. Specifically, the multiple summation values ​​of electrical charge generated according to step S201 are traversed sequentially from largest to smallest. Then, in each summation, it is determined whether the equalization channel 111 with the larger required discharge amount can be turned on. If it can be turned on, it is confirmed to be turned on. If it cannot be turned on, it is determined whether the equalization channel with the smaller required discharge amount can be turned on. If it can be turned on, it is confirmed to be turned on. This process continues, determining the two equalization channels 111 in the next summation, until n equalization channels are turned on. c The process involves summing the values ​​of each channel or all groups. The conditions for determining whether equalization channel 111 can be opened include channel constraints and whether the equalization channel 111 has completed the required discharge.

[0105] In one embodiment of the present invention, after completing step S200, the following steps can be performed: calibrating the maximum conduction number under different ambient temperatures to generate the maximum conduction number of the equalization module under any ambient temperature. Specifically, when adopting the above-mentioned optimal strategy, since the ambient temperature affects the maximum conduction number n... c The value of n is determined by the ambient temperature, therefore the maximum conduction number n needs to be calculated separately. c When n c When the theoretical value is inaccurate, it can be calibrated experimentally. In this embodiment, the maximum conduction number n at multiple different temperatures is first calculated. c Then, the maximum conduction number n of the equalization module under any ambient temperature is generated by linear interpolation. c .

[0106] In one embodiment of the invention, besides calibrating the initial n c0 Alternatively, PID (Proportional-Integral-Derivative) control can be used for online correction. In this embodiment, the maximum conduction number n under different ambient temperatures... c The following formula can be satisfied:

[0107]

[0108] Where, e(j) = T(j) - T max , where j represents the sampling time number. The parameters that need to be calibrated at this time include n. c0 k p k I kd .

[0109] In one embodiment of the present invention, due to the limitation of the control frequency of the equalization module 200, it is impossible to switch from r at the instant the temperature reaches the threshold. max n mac (t) instantly switches to r c n c Therefore, it is necessary to switch in advance to ensure that the temperature does not exceed the threshold. In practical applications, a linear switching method can be used as follows:

[0110] When T(t) ≤ T c At that time, r′(t)=r max n max (t);

[0111] When T(t) > T c And T(t)≤T max hour,

[0112] Among them, T c The temperature value, T, indicates when the switching should begin earlier. c <T max T c Calibration can be performed experimentally.

[0113] In one embodiment of the present invention, a step switching method can also be used to solve the limitation of the control frequency. The step switching method can be as follows:

[0114] When T(t) ≤ T c At that time, r′(t)=r max n max (t);

[0115] When T(t) > T c At that time, r′(t)=r c n c .

[0116] Furthermore, bang-bang (hysteresis) control can be used for switching:

[0117] When T(t) ≤ T c At that time, r′(t)=r max n max (t);

[0118] When T(t) > T c At that time, r′(t)=0.

[0119] In this embodiment, bang-bang control is used to maintain T. c <T maxThis control method is theoretically slightly worse than the optimal strategy, but it simplifies parameter calibration, reducing the number of parameters to be calibrated from two to one; only T needs to be calibrated. c That's all.

[0120] In one embodiment of the present invention, the generation parameter n can be calibrated under different ambient temperatures. c and T c This minimizes the discharge time. In practical applications, based on the current ambient temperature, linear interpolation can be performed within the calibrated ambient temperature range to obtain the final n. c and T c Multiple equalization modules 110 can use the same set of parameters for equalization, or they can use different parameters.

[0121] Please see Figure 5 As shown, Figure 5 The diagram shown illustrates a vehicle provided by the present invention. The electric vehicle 400 of the present invention may include the battery equalization controller described in the above embodiments. In practical applications, the battery equalization controller may be integrated into the vehicle's Battery Management System (BMS). In this embodiment, the electric vehicle 400 may include a battery management system 401, a power battery 402, and a vehicle control system 403. The battery management system 401 is electrically connected to the power battery 402 and the vehicle control system 403. The battery management system 401 can be used to monitor the status indicators of the power battery 402 and perform cell equalization. After integrating the battery equalization controller of the present invention, the battery management system 401 can effectively improve the battery equalization efficiency and shorten the equalization time.

[0122] In summary, this invention provides a power battery equalization controller, an equalization control method, and an electric vehicle, relating to the field of new energy battery technology. Under different ambient temperatures and initial charge levels, this invention can employ an optimal discharge strategy, improving power battery equalization efficiency, shortening equalization time, and thus enhancing power battery performance and lifespan. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0123] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A power battery equalization controller, characterized in that, include: The equalization control board includes multiple equalization modules, and each equalization module includes multiple equalization channels; as well as A processor is electrically connected to each of the equalization modules to control the activation of each of the equalization channels; Each of the equalization channels is electrically connected to one cell in the battery module; The processor is used to calculate the maximum conduction number of the equalization module based on the temperature constraint of the equalization module; The processor is further configured to determine the conduction state of the equalization channel in each equalization module based on the maximum number of conductions and the required discharge amount of each cell. The equalization channel includes: At least two balancing resistors are electrically connected to the positive and negative terminals of the battery cell, respectively. A switching transistor is electrically connected between the two equalizing resistors, wherein the processor is electrically connected to the control terminal of the switching transistor; The maximum conduction number of the equalization channel Satisfy the following formula: ； Where `round()` represents the rounding operation, `k` represents the thermal convection coefficient, and `A` represents the thermal convection area. Indicates the temperature constraint threshold. The ambient temperature is represented by I, the discharge current is represented by R, and the resistance value of the equalization resistor is represented by R. This indicates the duty cycle of the equalization channel.

2. The equalization controller for a power battery according to claim 1, characterized in that, Two adjacent equalization channels share one equalization resistor.

3. The equalization controller for a power battery according to claim 1, characterized in that, The equalization channel also includes a data interface, which is connected to an external sampling chip to obtain the output voltage and / or output current of each cell.

4. The equalization controller for a power battery according to claim 1, characterized in that, The equalization module also includes a temperature sensor for detecting the temperature of each equalization channel.

5. The equalization controller for a power battery according to claim 1, characterized in that, The processor is also used to: The required discharge amount of each of the battery cells is obtained, and the required discharge amounts of two adjacent battery cells are summed to generate multiple power sum values; The summation of the electrical quantities is iterated from largest to smallest, and the conduction state of each equalization channel is determined sequentially based on the maximum conduction count.

6. A method for equalization control of a power battery, characterized in that, The equalization controller applied to the power battery as described in claim 1, wherein the equalization control method includes: Based on the temperature constraint of the equalization module, calculate the maximum conduction number of the equalization module; and The conduction state of the equalization channel in each equalization module is determined based on the maximum number of conductions and the required discharge amount of each cell.

7. The equalization control method for a power battery according to claim 6, characterized in that, After the step of determining the conduction state of each equalization channel based on the required discharge amount of each cell and the maximum conduction number, the method further includes: The maximum conduction count is calibrated under different ambient temperatures to generate the maximum conduction count of the equalization module under any ambient temperature.

8. An electric vehicle, characterized in that, The equalization controller for the power battery as described in any one of claims 1 to 5.

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