CN113060019B - Power battery pack and control method thereof - Google Patents

Abstract

The present disclosure relates to a power battery pack and a control method thereof. The power battery pack includes N types of cells, the N types of cells are arranged alternately in sequence, the energy density of the first type of cells in the N types of cells is greater than the energy density of the second type of cells, the The thermal stability of the second type of cell is higher than that of the first type of cell, wherein, N is an integer, and N≥2. Through the above technical solution, different types of batteries with complementary energy density and thermal stability are alternately arranged in the power battery pack in sequence. Using this method of mixing and matching can make the power battery pack more powerful than a single use of the first type of batteries. Better thermal stability reduces the cost of using heat insulation materials, and has a higher energy density than the single use of the second type of battery, which improves the battery life of the vehicle to a certain extent. Using the charge and discharge control provided by this disclosure The method can safely and efficiently charge and discharge the power battery pack.

Description

Power battery pack and control method thereof

technical field

The present disclosure relates to the technical field of power battery pack structure and control, and in particular, to a power battery pack and a control method thereof.

Background technique

Divided from the differences in the structural layout of power battery packs, power battery packs can generally be divided into two types: module solutions and non-module solutions (CTP). In the module solution, the power battery pack is equipped with cells, end plates, side plates, busbars, heat insulation materials, etc. The CTP solution cancels the process of grouping the cells and directly assembles the cells into the case of the power battery pack. The battery system is usually ternary or lithium iron phosphate.

Usually the same type of battery is used in the power battery pack, for example, a ternary battery or a lithium iron phosphate battery. Among them, the energy density of the ternary battery is relatively high, but the thermal stability is poor, and thermal insulation materials such as airgel need to be arranged between the batteries to slow down the spread of thermal runaway and improve the safety of the whole package. Therefore, the thermal insulation material The dosage is larger and the cost is higher. Lithium iron phosphate batteries have good thermal stability, but the energy density is low, and the capacity of the batteries is significantly affected by temperature, and the problem of vehicle battery life attenuation in winter is relatively serious.

Contents of the invention

The purpose of the present disclosure is to provide a power battery pack with better stability and higher energy density and a control method thereof.

In order to achieve the above object, the present disclosure provides a power battery pack, the power battery pack includes N types of batteries, the N types of batteries are arranged alternately in order, and the first type of batteries in the N types of batteries The energy density is greater than the energy density of the second type of cell, and the thermal stability of the second type of cell is higher than that of the first type of cell, wherein N is an integer, and N≥2.

Optionally, the first type of battery is a ternary battery, the second type of battery is a lithium iron phosphate battery, or the first type of battery is a ternary 811 battery, and the second The similar batteries are ternary 523 batteries.

Optionally, the cell units in the N type cells are alternately arranged in sequence, wherein one cell of the same type of cell forms a cell unit, or a plurality of cells of the same type arranged together Form a cell unit.

Optionally, the same kind of batteries are electrically connected to form a battery module, and the power battery pack also includes a relay, which is used to connect the positive and negative poles of each battery module, the positive pole and the negative pole of the battery system power distribution box Turn on and off between any two.

The present disclosure also provides a method for controlling the above-mentioned power battery pack, in which similar cells are electrically connected to form a cell module, and the method includes:

Detect the status of the vehicle;

If the whole vehicle is in the driving state, it controls to connect N battery modules in series to supply power to the whole vehicle;

If the whole vehicle is in the brake feedback state, then control to connect N battery modules in series to perform feedback;

If the whole vehicle is in the state of being charged with a gun inserted, one or more of the N battery modules are controlled to be charged according to the SOC of the power battery pack.

Optionally, if the whole vehicle is in the driving state, the control connects N battery modules in series to supply power to the whole vehicle, including:

If the whole vehicle is in the driving state, then determine the target power of driving;

The N battery modules are controlled to be connected in series to supply power to the whole vehicle with the target power of the driving.

Optionally, determining the target power for driving includes:

According to the SOC of the power battery pack and the temperature of each cell module, respectively determine the available discharge power of each cell module;

The minimum value of the available discharge power of each cell module is taken as the target power of the driving.

Optionally, according to the SOC of the power battery pack and the temperature of each battery module, respectively determine the available discharge power of each battery module, including:

In the predetermined discharge corresponding relationship, the discharge power corresponding to both the current SOC of the power battery pack and the current highest cell temperature in a cell module is determined as the first discharge power, and the predetermined discharge corresponds to The relationship is the correspondence between the SOC of the power battery pack, the temperature of the battery in the battery module, and the discharge power;

In the predetermined discharge correspondence, the discharge power corresponding to both the current SOC of the power battery pack and the current lowest cell temperature in the cell module is determined as the second discharge power;

The smaller value of the first discharge power and the second discharge power is determined as the available discharge power of the cell module.

Optionally, if the whole vehicle is in the brake feedback state, then the controller connects N battery modules in series to perform feedback, including:

If the whole vehicle is in the braking feedback state, determine the target power of the braking feedback;

Controlling the series connection of the N battery modules to perform regenerative charging with the target power of the braking regenerative.

Optionally, determining the target power of braking feedback includes:

According to the SOC of the power battery pack and the temperature of each cell module, respectively determine the available feedback power of each cell module;

The minimum value of the available feedback power of each cell module is taken as the target power of the braking feedback.

Optionally, according to the SOC of the power battery pack and the temperature of each battery module, respectively determine the available feedback power of each battery module, including:

In the predetermined feedback corresponding relationship, the feedback power corresponding to both the current SOC of the power battery pack and the current highest battery temperature in a battery module is determined as the first feedback power, and the predetermined feedback corresponds to The relationship is the correspondence between the SOC of the power battery pack, the temperature of the battery in the battery module, and the feedback power;

In the predetermined feedback correspondence, the discharge power corresponding to both the current SOC of the power battery pack and the current lowest battery temperature in the battery module is determined as the second feedback power;

The smaller value of the first feedback power and the second feedback power is determined as the available feedback power of the cell module.

Optionally, if the whole vehicle is in the state of being charged with a gun plugged in, one or more of the N battery modules are controlled according to the SOC of the power battery pack to be charged, including:

If the whole vehicle is in the state of charging with a gun inserted, then determine the SOC of the power battery pack;

If the SOC of the power battery pack is less than a predetermined charging threshold, control the N battery modules to be connected in series;

Determine the target power for vehicle charging;

Controlling to charge the N battery cell modules with the target power for charging the whole vehicle.

Optionally, determining the target power for vehicle charging includes:

According to the SOC of the power battery pack and the temperature of each battery module, respectively determine the available charging power of each battery module;

The minimum value of the available charging power of each battery module is taken as the target power for charging the whole vehicle.

Optionally, according to the SOC of the power battery pack and the temperature of each battery module, the available charging power of each battery module is determined respectively, including:

In the predetermined charging correspondence, the charging power corresponding to both the current SOC of the power battery pack and the current highest cell temperature in a cell module is determined as the first charging power, and the predetermined charging corresponds to The relationship is the correspondence between the SOC of the power battery pack, the temperature of the battery in the battery module, and the charging power;

In the predetermined charging correspondence, the charging power corresponding to both the current SOC of the power battery pack and the current lowest battery temperature in the battery module is determined as the second charging power;

The smaller value of the first charging power and the second charging power is determined as the available charging power of the cell module.

Optionally, the method also includes:

If the SOC of the power battery pack is greater than or equal to the predetermined charge threshold, control is performed to charge each of the N battery modules one by one.

Through the above technical solution, different types of cells with complementary energy density and thermal stability are alternately arranged in the power battery pack in sequence. Using this mix-and-match method can make the power battery pack more powerful than a single use of the first type of cells. Better thermal stability reduces the cost of using heat insulation materials, and has a higher energy density than the single use of the second type of battery, which improves the battery life of the vehicle to a certain extent. Using the charge and discharge control provided by this disclosure The method can safely and efficiently charge and discharge the power battery pack.

Other features and advantages of the present disclosure will be described in detail in the detailed description that follows.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present disclosure, and constitute a part of the description, together with the following specific embodiments, are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the attached picture:

Fig. 1 is a schematic diagram of a power battery pack provided by an exemplary embodiment;

Fig. 2 is a schematic diagram of a power battery pack provided by another exemplary embodiment;

Fig. 3 is a flowchart of a control method for a power battery pack provided by an exemplary embodiment;

Fig. 4a is a schematic diagram of the connection relationship of each terminal in the power distribution box of the battery system provided by an exemplary embodiment;

Fig. 4b is a schematic diagram of the connection relationship of each terminal in the BDU provided by another exemplary embodiment;

Fig. 4c is a schematic diagram of the connection relationship of each terminal in the BDU provided by another exemplary embodiment;

Fig. 5 is a flowchart of a control method for a power battery pack provided by another exemplary embodiment.

Detailed ways

Specific embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

The present disclosure provides a power battery pack, which includes N types of cells, and the N types of cells are alternately arranged in sequence. The energy density of the first type of cells in the N type of cells is greater than the energy density of the second type of cells, and the thermal stability of the second type of cells is higher than that of the first type of cells. Wherein, N is an integer, and N≥2.

Some cells have a complementary relationship in terms of energy density and thermal stability. For example, a power battery pack includes two types of cells: the first type of cells and the second type of cells. If all the first-type batteries are used in the power battery pack, although it has a relatively high energy density, its thermal stability is poor, and it is easy to cause thermal runaway to spread. If all the second-type batteries are used in the power battery pack, although the thermal stability is better, the energy density is poor, resulting in poor endurance of the vehicle. By arranging these two types of cells alternately, the first type of cells is separated by the second type of cells, which slows down the spread of thermal runaway. As for the electrical connection relationship of the N-type batteries, various possible connection methods can be adopted under the premise of ensuring safety.

Through the above technical solution, different types of cells with complementary energy density and thermal stability are alternately arranged in the power battery pack in sequence. Using this mix-and-match method can make the power battery pack more powerful than a single use of the first type of cells. Better thermal stability reduces the cost of using heat insulation materials, and has a higher energy density than the single use of the second type of battery, which improves the battery life of the vehicle to a certain extent. Using the charge and discharge control provided by this disclosure The method can safely and efficiently charge and discharge the power battery pack.

For example, N=2, the first type of battery can be a ternary battery, and the second type of battery can be a lithium iron phosphate battery. Alternatively, the first type of battery is a ternary 811 battery, and the second type of battery is a ternary 523 battery.

Fig. 1 is a schematic diagram of a power battery pack provided by an exemplary embodiment. As shown in Figure 1, a single ternary cell 1 and a single lithium iron phosphate cell 2 are alternately arranged to form an "ABAB" layout.

In another embodiment, the cell units in N types of cells are alternately arranged in sequence, wherein one cell of the same type of cell forms one cell unit, or, a plurality of cells of the same type arranged together The cells form a cell unit. Figure 1 shows the situation where one battery cell of the same type forms one battery cell unit.

Fig. 2 is a schematic diagram of a power battery pack provided by another exemplary embodiment. As shown in Figure 2, two ternary cells 1 are used as a cell unit, and two lithium iron phosphate cells 2 are used as a cell unit. The cell units of the two types of cells are arranged alternately to form an "AABBAABB" layout.

If N=3, the N-type batteries may include ternary 811 batteries, ternary 523 batteries and lithium iron phosphate batteries. The energy density of lithium iron phosphate battery, ternary 523 battery and ternary 811 battery gradually increases in turn, and the thermal stability of lithium iron phosphate battery, ternary 523 battery and ternary 811 battery gradually decreases. The form of "ABCABC" or "AABBCC" can be used in the layout of the three types of cells.

Regarding the electrical connection relationship between the various cells, the same type of cells can be electrically connected through bus bars to form a cell module. Each cell module can be connected in series to output power supply, or each cell module can be connected in parallel to output power supply, or a mixed connection method of parallel and series can be adopted. The connection relationship between each cell module can be fixed, or can be set to be adjustable by setting a relay. In yet another embodiment, the power battery pack may further include a relay, and the relay is used to connect any two of the positive pole and the negative pole of each cell module, the positive pole and the negative pole of the battery system distribution unit (Battery System Distribution Unit, BDU) between conduction and disconnection. In this way, the vehicle can be powered by the positive and negative poles of the BDU.

Fig. 3 is a flowchart of a control method for a power battery pack provided by an exemplary embodiment. As shown in Fig. 3, the method may include the following steps.

Step S11, detecting the state of the whole vehicle.

Step S12, if the whole vehicle is in the driving state, control to connect N battery modules in series to supply power to the whole vehicle.

Step S13, if the whole vehicle is in the brake feedback state, control to connect N battery modules in series to perform feedback.

Step S14, if the whole vehicle is in the charging state with the plug in, control one or more of the N battery modules to charge according to the SOC of the power battery pack.

Wherein, the driving state refers to other driving states except the brake feedback. In this embodiment, in the driving state and braking feedback state, N battery modules are connected in series, the positive pole after series connection is connected to the positive pole of BDU, and the negative pole after series connection is connected to the negative pole of BDU. When the whole vehicle is in the charging state, the connection relationship between each battery module and the positive and negative poles of the BDU needs to be controlled according to the SOC of the power battery pack. In this embodiment, according to the size of the SOC of the power battery pack, the N battery modules are charged more reasonably, which not only considers the charging efficiency, but also avoids overcharging of a certain battery module.

Fig. 4a is a schematic diagram of the connection relationship of each terminal in the power distribution box of the battery system provided by an exemplary embodiment. As shown in Figure 4a, the positive electrode A+ of the battery module corresponding to the first type of battery (hereinafter referred to as the first battery module) and the battery module corresponding to the second type of battery (hereinafter referred to as the second battery module) The negative pole B- of the first battery module is connected to the negative pole (-) of the BDU, and the positive pole B+ of the second battery module is connected to the positive pole (+) of the BDU. Through this connection method, the first battery module and the second battery module can be connected in series to supply power to the outside together, or the charging gun can charge the first battery module and the second battery module together.

Fig. 4b is a schematic diagram of the connection relationship of each terminal in the BDU provided by another exemplary embodiment. As shown in FIG. 4b, the positive pole A+ of the first battery module is connected to the positive pole (+) of the BDU, and the negative pole A- of the first battery module is connected to the negative pole (-) of the BDU. Through this connection, the charging gun can charge the first battery module independently.

Fig. 4c is a schematic diagram of the connection relationship of each terminal in the BDU provided by yet another exemplary embodiment. As shown in FIG. 4c, the positive pole B+ of the second battery module is connected to the positive pole (+) of the BDU, and the negative pole B- of the second battery module is connected to the negative pole (-) of the BDU. Through this connection mode, the charging gun can charge the second battery module independently. For example, the battery management system (Battery Management System, BMS) can control the opening and closing of multiple relays in the power battery pack according to the status of the vehicle to realize the connection relationship in Figure 4a-Figure 4c.

In yet another embodiment, on the basis of Fig. 3, if the whole vehicle is in the driving state, the step of controlling the connection of N battery modules in series to supply power to the whole vehicle (step S12) may include: if the whole vehicle is in the driving state , then determine the target power for driving; control the series connection of N battery modules to supply power to the whole vehicle with the target power for driving.

If the whole vehicle is in the driving state and N=2, the BDU can control the opening and closing of the relay to connect the two battery modules according to the connection method in Figure 4a, and then supply power to the whole vehicle through the positive and negative poles of the BDU. A variety of methods can be used to determine the target power for driving, and the power battery pack is used to supply power to the vehicle at the target power for driving to ensure safety and efficient output of power.

Wherein, the above-mentioned step of determining the target power for driving may include: respectively determining the available discharge power of each battery module according to the SOC of the power battery pack and the temperature of each battery module; As the driving target power.

Since N battery modules are connected in series, if the available discharge power of each battery module is different, the minimum value of the available discharge power of each battery module can be taken as the target power for driving, thus ensuring a smaller available discharge power If the battery module can be safely discharged, then the battery module with larger available discharge power can also be safely discharged. This solution can ensure the safety of power battery discharge.

The available discharge power of the cell module can be determined according to the temperature of each cell and the SOC of the power battery pack. In yet another embodiment, the above step of determining the available discharge power of each cell module according to the SOC of the power battery pack and the temperature of each cell module may include:

In the predetermined discharge correspondence, the discharge power corresponding to both the current SOC of the power battery pack and the current highest cell temperature in a battery module is determined as the first discharge power, and the predetermined discharge correspondence is the power battery The corresponding relationship between the SOC of the package, the temperature of the battery in the battery module, and the discharge power;

In the predetermined discharge correspondence, the discharge power corresponding to both the current SOC of the power battery pack and the current lowest cell temperature in the cell module is determined as the second discharge power;

The smaller value of the first discharge power and the second discharge power is determined as the available discharge power of the cell module.

The predetermined discharge correspondence relationship may be a predetermined discharge map. Detect the SOC of the power battery pack in real time. For a cell module, detect the temperature of multiple cells in it, and determine the maximum and minimum values of the cell temperature. The maximum values of the real-time SOC and cell temperature correspond to the first discharge power, and the real-time minimum values of the SOC and cell temperature correspond to the second discharge power. In this way, it is ensured that the battery cell corresponding to the smaller discharge power can be safely discharged, and then the battery cell with a larger discharge power can also be safely discharged, and the security of the discharge of the power battery can be guaranteed through this solution.

In yet another embodiment, on the basis of FIG. 3 , if the whole vehicle is in the braking feedback state, the step of controlling the connection of N battery modules in series and performing feedback (step S12) may include: if the whole vehicle is in the braking feedback state, In the feedback state, determine the target power of braking feedback; control the series connection of N battery modules to perform feedback charging with the target power of braking feedback.

If the whole vehicle is in the brake feedback state, and N=2, the BDU can control the opening and closing of the relay to connect the two battery modules according to the connection method in Figure 4a, and then brake through the positive and negative poles of the BDU give back. A variety of methods can be used to determine the target power of braking feedback, and control the power battery pack to perform regenerative charging at the target power of braking feedback to ensure safety and efficient power feedback.

Wherein, the above-mentioned step of determining the target power of braking feedback may include: respectively determining the available feedback power of each battery module according to the SOC of the power battery pack and the temperature of each battery module; The minimum value is used as the target power of braking feedback.

Since N battery modules are connected in series, if the available feedback power of each battery module is different, the minimum value of the available feedback power of each battery module can be taken as the target power of braking feedback, thus ensuring a minimum available feedback power. If the battery module with regenerative power can be fed back safely, then the battery module with larger available regenerative power can also be fed back safely. Through this scheme, the safety of regenerative charging of the power battery can be guaranteed.

The available feedback power of the cell module can be determined according to the temperature of each cell and the SOC of the power battery pack. In yet another embodiment, the above step of determining the available feedback power of each cell module according to the SOC of the power battery pack and the temperature of each cell module may include:

In the predetermined feedback correspondence, the feedback power corresponding to both the current SOC of the power battery pack and the current highest cell temperature in a cell module is determined as the first feedback power, and the predetermined feedback correspondence is the power battery The corresponding relationship between the SOC of the package, the temperature of the battery in the battery module, and the feedback power;

In the predetermined feedback correspondence, the discharge power corresponding to both the current SOC of the power battery pack and the current lowest battery temperature in the battery module is determined as the second feedback power;

The smaller value of the first feedback power and the second feedback power is determined as the available feedback power of the cell module.

The predetermined feedback correspondence relationship may be a predetermined feedback map. Detect the SOC of the power battery pack in real time. For a cell module, detect the temperature of multiple cells in it, and determine the maximum and minimum values of the cell temperature. The real-time maximum value of the SOC and the battery temperature corresponds to the first feedback power, and the real-time minimum value of the SOC and the battery temperature corresponds to the second feedback power. In this way, it is ensured that the battery cell corresponding to the smaller feedback power can be fed back safely, and the battery cell with larger feedback power can also be fed back safely, and the security of power battery power feedback can be guaranteed through this scheme.

In yet another embodiment, on the basis of Fig. 3, if the whole vehicle is in the state of being charged with a gun plugged in, the step of controlling one or more of the N battery modules to charge according to the SOC of the power battery pack (step S12) Can include:

If the whole vehicle is in the state of being charged with a gun, then determine the SOC of the power battery pack; if the SOC of the power battery pack is less than the predetermined charging threshold, then control N battery modules to be connected in series; determine the target power for charging the whole vehicle; The target power of car charging is used to charge N battery modules.

If the whole vehicle is in the state of plugging in and charging, and N=2, in the case that the SOC of the power battery pack is less than the predetermined charging threshold, the BDU can control the opening and closing of the relay to make the two battery modules follow the charging conditions shown in Figure 4a. The connection method is connected, and then charged through the positive and negative poles of the BDU. A variety of methods can be used to determine the target power for vehicle charging, and control the power battery pack to charge at the target power for vehicle charging to ensure safety and efficient charging.

When the SOC of the power battery pack is less than the predetermined charging threshold, it can be considered that the series charging of each battery module has better safety, and at this time, the series charging can take into account both safety and charging efficiency. The predetermined charging threshold can be determined experimentally or empirically.

Wherein, the above-mentioned step of determining the target power for charging the whole vehicle may include: respectively determining the available charging power of each battery module according to the SOC of the power battery pack and the temperature of each battery module; The minimum value is used as the target power for vehicle charging.

Since N battery modules are connected in series, if the available charging power of each battery module is different, the minimum value of the available charging power of each battery module can be taken as the target power for charging the vehicle, thus ensuring a minimum available charging power. If the battery module with charging power can be safely charged, then the battery module with larger available charging power can also be safely charged. This solution can ensure the safety of power battery charging.

The available charging power of the cell module can be determined according to the temperature of each cell and the SOC of the power battery pack. In yet another embodiment, the above-mentioned step of determining the available charging power of each battery module according to the SOC of the power battery pack and the temperature of each battery module may include:

In the predetermined charging correspondence, the charging power corresponding to both the current SOC of the power battery pack and the current highest battery temperature in a battery module is determined as the first charging power, and the predetermined charging correspondence is the power battery The corresponding relationship between the SOC of the package, the temperature of the battery in the battery module, and the charging power;

In the predetermined charging correspondence, the charging power corresponding to both the current SOC of the power battery pack and the current lowest battery temperature in the battery module is determined as the second charging power;

The smaller value of the first charging power and the second charging power is determined as the available charging power of the cell module.

The predetermined charging correspondence can be a predetermined charging map. Detect the SOC of the power battery pack in real time. For a cell module, detect the temperature of multiple cells in it, and determine the maximum and minimum values of the cell temperature. The maximum value of the real-time SOC and the battery temperature corresponds to the first charging power, and the real-time minimum value of the SOC and the battery temperature corresponds to the second charging power. In this way, it is ensured that the battery cell corresponding to a relatively small charging power can be safely charged, and naturally the battery cell with a relatively large charging power can also be safely charged. This solution can ensure the safety of power battery charging.

In yet another embodiment, the method may further include: if the SOC of the power battery pack is greater than or equal to a predetermined charging threshold, controlling to charge each of the N battery modules one by one.

If the SOC of the power battery pack is greater than or equal to the predetermined charging threshold, it can be considered that charging N battery modules in series cannot guarantee its safety, and some battery modules may be overcharged. At this point, each cell module can be charged one by one. For example, the first battery module can be controlled to be fully charged according to the connection mode of FIG. 4b first, and then the second battery module can be controlled to be fully charged according to the connection mode of FIG. 4c. Specifically, the method for charging a single battery module can be implemented with reference to the method for charging a power battery pack in the related art. In this embodiment, charging safety is ensured by sacrificing some charging efficiency.

Fig. 5 is a flowchart of a control method for a power battery pack provided by another exemplary embodiment. In this embodiment, N=2. As shown in Fig. 5, the method may include the following steps.

1. BMS diagnoses the status of the vehicle;

2. If the whole vehicle is in the driving state, the BMS sends an instruction to the BDU to connect the battery cell A (first type battery cell) circuit (first battery cell module) and battery cell B (second type battery cell) circuit (second cell module) in series;

3. Determine the available discharge power PA1 of the battery module A according to the collected temperature of the battery module A (that is, the first battery module) and the SOC of the power battery pack;

4. Determine the available discharge power PB1 of the battery module B according to the collected temperature of the battery module B (that is, the second battery module) and the SOC of the power battery pack;

5. Determine the target power of driving as Min(PA1, PB1);

6. Control the power battery pack to supply power to the whole vehicle with the target power of driving;

7. If the whole vehicle is in the braking feedback state, the BMS sends an instruction to the BDU to connect the battery A circuit and the battery B circuit in series;

8. Determine the available feedback power PA2 of the battery module A according to the collected temperature of the battery module A and the SOC of the power battery pack;

9. Determine the available feedback power PB2 of the battery module B according to the collected temperature of the battery module B and the SOC of the power battery pack;

10. Determine the target power of braking feedback as Min(PA2, PB2);

11. Control the power battery pack to perform feedback charging with the target power of braking feedback;

12. If the charging gun is plugged in, and the SOC value of the power battery pack is less than the predetermined charging threshold a, the BMS sends an instruction to the BDU to connect the cell A circuit and the cell B circuit in series;

13. Determine the available charging power PA3 of the battery module A according to the collected temperature of the battery module A and the SOC of the power battery pack;

14. Determine the available charging power PB3 of the battery module B according to the collected temperature of the battery module B and the SOC of the power battery pack;

15. Request charging current from the charging pile according to Min(PA3, PB3);

16. If the charging gun is plugged in, and the SOC value of the power battery pack is greater than or equal to the predetermined charging threshold a, the BMS sends an instruction to the BDU to separately connect the battery A circuit to the BDU's total positive and total negative for charging;

17. Determine the available charging power PA3 of the battery module A according to the collected temperature and SOC of the battery module A, and request the charging current from the charging pile according to PA3;

18. If the battery cell A circuit is full, then determine the available charging power PB3 of the battery cell module B according to the collected temperature and SOC of the battery cell module B, and request the charging current from the charging pile according to PB3;

19. If the B circuit of the battery cell is fully charged and the charging is completed, the BMS sends an instruction to the BDU to connect the A circuit of the battery cell and the B circuit of the battery cell in series, and it is ready for the next discharge.

The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure. These simple modifications all belong to the protection scope of the present disclosure.

In addition, it should be noted that the various specific technical features described in the above specific implementation manners may be combined in any suitable manner if there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not further described in this disclosure.

In addition, various implementations of the present disclosure can be combined arbitrarily, as long as they do not violate the idea of the present disclosure, they should also be regarded as the content disclosed in the present disclosure.

Claims (10)

1. A control method for a power battery pack, characterized in that the power battery pack includes N types of cells, the N types of cells are arranged alternately in sequence, and the first type of cells in the N types of cells The energy density of the second type of cell is greater than the energy density of the second type of cell, and the thermal stability of the second type of cell is higher than the thermal stability of the first type of cell, wherein, N is an integer, N≥2; The electric cells of the same kind are electrically connected to form a cell module, and the power battery pack also includes a relay, which is used to connect any two of the positive and negative electrodes of each cell module and the positive and negative electrodes of the battery system power distribution box. between conduction and disconnection; The methods include: Detect the status of the vehicle; If the whole vehicle is in the driving state, it controls to connect N battery modules in series to supply power to the whole vehicle; If the whole vehicle is in the brake feedback state, then control to connect N battery modules in series to perform feedback; If the whole vehicle is in the state of being charged with a plug-in gun, one or more of the N battery modules are controlled to be charged according to the SOC of the power battery pack; If the whole vehicle is in the driving state, the control connects N battery modules in series to supply power to the whole vehicle, including: If the whole vehicle is in the driving state, then determine the target power of driving; Controlling the series connection of the N battery modules to supply power to the whole vehicle with the target power of the driving; Determine the target power for driving, including: According to the SOC of the power battery pack and the temperature of each cell module, respectively determine the available discharge power of each cell module; Taking the minimum value of the available discharge power of each cell module as the target power of the driving; According to the SOC of the power battery pack and the temperature of each battery module, respectively determine the available discharge power of each battery module, including: In the predetermined discharge corresponding relationship, the discharge power corresponding to both the current SOC of the power battery pack and the current highest cell temperature in a cell module is determined as the first discharge power, and the predetermined discharge corresponds to The relationship is the correspondence between the SOC of the power battery pack, the temperature of the battery in the battery module, and the discharge power; In the predetermined discharge correspondence, the discharge power corresponding to both the current SOC of the power battery pack and the current lowest cell temperature in the cell module is determined as the second discharge power; The smaller value of the first discharge power and the second discharge power is determined as the available discharge power of the cell module. 2. The method according to claim 1, characterized in that, if the whole vehicle is in the brake feedback state, then control to connect N battery modules in series to perform feedback, including: If the whole vehicle is in the braking feedback state, determine the target power of the braking feedback; Controlling the series connection of the N battery modules to perform regenerative charging with the target power of the braking regenerative. 3. The method according to claim 2, wherein determining the target power of braking feedback comprises: According to the SOC of the power battery pack and the temperature of each cell module, respectively determine the available feedback power of each cell module; The minimum value of the available feedback power of each cell module is taken as the target power of the braking feedback. 4. The method according to claim 3, wherein, according to the SOC of the power battery pack and the temperature of each battery module, the available feedback power of each battery module is respectively determined, including: In the predetermined feedback corresponding relationship, the feedback power corresponding to both the current SOC of the power battery pack and the current highest battery temperature in a battery module is determined as the first feedback power, and the predetermined feedback corresponds to The relationship is the correspondence between the SOC of the power battery pack, the temperature of the battery in the battery module, and the feedback power; In the predetermined feedback correspondence, the feedback power corresponding to both the current SOC of the power battery pack and the current lowest battery temperature in the battery module is determined as the second feedback power; The smaller value of the first feedback power and the second feedback power is determined as the available feedback power of the cell module. 5. The method according to claim 1, wherein, if the whole vehicle is in the state of being charged with a gun inserted, one or more of the N battery modules are controlled to be charged according to the SOC of the power battery pack, include: If the whole vehicle is in the state of charging with a gun inserted, then determine the SOC of the power battery pack; If the SOC of the power battery pack is less than a predetermined charging threshold, control the N battery modules to be connected in series; Determine the target power for vehicle charging; Controlling to charge the N battery cell modules with the target power for charging the whole vehicle. 6. The method according to claim 5, wherein determining the target power for charging the vehicle comprises: According to the SOC of the power battery pack and the temperature of each battery module, respectively determine the available charging power of each battery module; The minimum value of the available charging power of each battery module is taken as the target power for charging the whole vehicle. 7. The method according to claim 6, wherein, according to the SOC of the power battery pack and the temperature of each battery module, the available charging power of each battery module is respectively determined, including: In the predetermined charging correspondence, the charging power corresponding to both the current SOC of the power battery pack and the current highest cell temperature in a cell module is determined as the first charging power, and the predetermined charging corresponds to The relationship is the correspondence between the SOC of the power battery pack, the temperature of the battery in the battery module, and the charging power; In the predetermined charging correspondence, the charging power corresponding to both the current SOC of the power battery pack and the current lowest battery temperature in the battery module is determined as the second charging power; The smaller value of the first charging power and the second charging power is determined as the available charging power of the cell module. 8. The method according to claim 5, further comprising: If the SOC of the power battery pack is greater than or equal to the predetermined charging threshold, control is performed to charge each of the N battery modules one by one. 9. The method according to claim 1, wherein the first type of battery is a ternary battery, the second type of battery is a lithium iron phosphate battery, or the first type of battery is It is a ternary 811 battery, and the second type of battery is a ternary 523 battery. 10. The method according to claim 1, wherein the cell units in the N types of cells are arranged alternately in sequence, wherein one cell of the same type forms a cell unit, or, one cell unit of the same type A plurality of battery cells arranged together form a battery cell unit.

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