Battery control method, vehicle-mounted controller, battery control system, and automobile

Abstract

The application discloses a battery control method, a vehicle-mounted controller, a battery control system and a car. The method comprises the following steps: acquiring a current state of a battery pack and measured data corresponding to the current state; determining a low-temperature power limit value and a high-temperature power limit value of the battery pack based on the current state and the measured data; determining a smaller value between the low-temperature power limit value and the high-temperature power limit value as a target power limit value of the battery pack; and controlling the battery pack to work based on the target power limit value. The method considers the current state of the battery pack and the measured data corresponding to the current state, compares the low-temperature power limit value corresponding to the current state with the high-temperature power limit value, and determines the target power limit value corresponding to the current state, so that the minimum power limit value of the battery pack can be determined more accurately, and the method has high application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a battery control method, a vehicle-mounted controller, a battery control system and an automobile. BACKGROUND

[0002] With the continuous increase of the power capability of the battery pack in the electric vehicle, the heat generation of the battery pack also increases, and the battery pack usually needs to be cooled to enhance the heat dissipation capability of the battery pack. The current mainstream cooling method will cause a large temperature difference between the bottom and the top of the battery pack, and the large temperature difference will cause different charging and discharging capabilities between different battery cells and different parts of the same battery cell. In severe driving conditions or in a high-temperature environment, fast charging, the individual positions of the battery cells in the battery pack are prone to exceed the charging and discharging capacity, which not only reduces the service life of the battery pack, but also easily causes safety risks such as lithium precipitation of the negative electrode of the battery cell, and reduces the working performance and safety performance of the battery pack.

[0003] Therefore, it is necessary to limit the power of the battery pack, control the charging and discharging work of each position of the battery pack below the power limit, so as to improve the service life of the battery pack and improve the working performance and safety performance of the battery pack. In the prior art, the power limit of the battery pack is usually estimated directly by the temperature of the battery cell in the battery pack. However, this direct estimation method is relatively rough and cannot accurately obtain the power limit of the battery pack, and thus cannot reasonably control the power of the battery pack. Therefore, how to accurately determine the power limit of the battery pack is a technical problem to be solved at present. SUMMARY

[0004] The embodiments of the present application provide a battery control method, a vehicle-mounted controller, a battery control system and an automobile to solve the problem of how to accurately determine the power limit of the battery pack.

[0005] A battery control method comprises:

[0006] obtaining a current state of a battery pack and measured data corresponding to the current state;

[0007] determining a low-temperature power limit and a high-temperature power limit of the battery pack based on the current state and the measured data;

[0008] determining the smaller one of the low-temperature power limit and the high-temperature power limit as a target power limit of the battery pack;

[0009] controlling the battery pack to work based on the target power limit.

[0010] Preferably, the measured data comprises a lowest top temperature and a highest top temperature.

[0011] The determining the low-temperature power limit value and the high-temperature power limit value of the battery pack based on the current state and the measured data comprises:

[0012] The determining the low-temperature power limit value of the battery pack based on the current state, the lowest top temperature and the preset temperature difference;

[0013] The determining the high-temperature power limit value of the battery pack based on the highest top temperature of the battery pack.

[0014] Preferably, the measured data further comprises a measured remaining capacity;

[0015] The determining the low-temperature power limit value and the high-temperature power limit value of the battery pack based on the current state and the measured data further comprises:

[0016] The determining the low-temperature power limit value of the battery pack based on the current state, the lowest top temperature, the measured remaining capacity and the preset temperature difference;

[0017] The determining the high-temperature power limit value of the battery pack based on the highest top temperature of the battery pack and the measured remaining capacity.

[0018] Preferably, the determining the low-temperature power limit value of the battery pack based on the current state, the lowest top temperature, the measured remaining capacity and the preset temperature difference comprises:

[0019] The determining a first power limit value based on the lowest top temperature of the battery pack and the measured remaining capacity;

[0020] The determining a second power limit value of the battery pack based on the lowest top temperature of the battery pack, the measured remaining capacity and the preset temperature difference;

[0021] The determining the low-temperature power limit value of the battery pack based on the current state, the first power limit value and the second power limit value.

[0022] Preferably, the determining the second power limit value of the battery pack based on the lowest top temperature of the battery pack, the measured remaining capacity and the preset temperature difference comprises:

[0023] The determining a lowest bottom temperature of the battery pack based on the lowest top temperature and the preset temperature difference;

[0024] The determining the second power limit value of the battery pack based on the lowest bottom temperature of the battery pack and the measured remaining capacity.

[0025] Preferably, the determining the low-temperature power limit value of the battery pack based on the current state, the first power limit value and the second power limit value comprises:

[0026] if the current state is not in the cooling state, determining the low-temperature power limit of the battery pack as the first power limit;

[0027] if the current state is in the cooling state for a time less than a first time, determining the low-temperature power limit of the battery pack to transition from the first power limit to the second power limit;

[0028] if the current state is in the cooling state for a time greater than or equal to the first time, determining the low-temperature power limit of the battery pack as the second power limit;

[0029] if the current state is out of the cooling state for a time less than a second time, determining the low-temperature power limit of the battery pack to transition from the second power limit to the first power limit;

[0030] if the current state is out of the cooling state for a time greater than or equal to the second time, determining the low-temperature power limit of the battery pack as the first power limit.

[0031] Preferably, before the current state and the measured data of the battery pack are obtained, the battery control method further comprises:

[0032] testing the battery pack to obtain a top test temperature and a bottom test temperature of the battery pack;

[0033] based on the top test temperature and the bottom test temperature, determining a maximum test temperature difference after the battery pack enters the cooling state and a first time corresponding to the maximum test temperature difference, and determining a minimum test temperature difference after the battery pack exits the cooling state and a second time corresponding to the minimum test temperature difference;

[0034] determining the maximum test temperature difference as the preset temperature difference, and storing the preset temperature difference, the first time and the second time.

[0035] A vehicle-mounted controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned battery control method when executing the computer program.

[0036] A battery control system comprising a sensor, a battery pack and the above-mentioned vehicle-mounted controller, wherein the sensor is connected to the battery pack and the vehicle-mounted controller respectively, and the battery pack is connected to the vehicle-mounted controller.

[0037] An automobile comprising the above-mentioned battery control system.

[0038] The battery control method, the vehicle-mounted controller, the battery control system and the automobile can accurately determine the low-temperature power limit value and the high-temperature power limit value corresponding to the current state of the battery pack. By comparing the low-temperature power limit value and the high-temperature power limit value corresponding to the current state of the battery pack, and determining the smaller one, the target power limit value corresponding to the current state of the battery pack can be accurately determined. Controlling the battery pack to work based on the target power limit value corresponding to the current state can avoid the risk of reducing the service life of the battery pack and the safety risk caused by exceeding the charging and discharging capacity, and can effectively improve the working performance and safety performance of the battery pack. The method takes the current state of the battery pack and the measured data corresponding to the current state into account, compares the low-temperature power limit value and the high-temperature power limit value corresponding to the current state, and determines the target power limit value corresponding to the current state, which can accurately determine the minimum power limit value of the battery pack, and has high application value. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0040] Figure 1 is a flowchart of a battery control method in an embodiment of the present application;

[0041] Figure 2 is another flowchart of a battery control method in an embodiment of the present application;

[0042] Figure 3 is another flowchart of a battery control method in an embodiment of the present application;

[0043] Figure 4 is another flowchart of a battery control method in an embodiment of the present application;

[0044] Figure 5 is another flowchart of a battery control method in an embodiment of the present application;

[0045] Figure 6 is another flowchart of a battery control method in an embodiment of the present application;

[0046] Figure 7 is a schematic diagram of a vehicle-mounted controller in an embodiment of the present application. DETAILED DESCRIPTION

[0047] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below, obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0048] The battery control method provided by the embodiments of the present application can be applied to a vehicle-mounted controller in a vehicle, and is used to achieve the purpose of more accurately determining the power limit value of a battery pack.

[0049] In an embodiment, as shown in Figure 1 , a battery control method is provided, and the vehicle-mounted controller in the vehicle is taken as an example to illustrate the method, which comprises the following steps: Figure 7

[0050] S101: obtaining a current state of the battery pack and measured data corresponding to the current state;

[0051] S102: determining a low-temperature power limit value and a high-temperature power limit value of the battery pack based on the current state and the measured data;

[0052] S103: determining the smaller one of the low-temperature power limit value and the high-temperature power limit value as a target power limit value of the battery pack;

[0053] S104: controlling the battery pack to work based on the target power limit value.

[0054] The current state refers to the current working state of the battery pack. The measured data refers to the data of the battery pack in the current state.

[0055] As an example, in step S101, the vehicle-mounted controller identifies the working state of the battery pack, determines the current state of the battery pack, and obtains the measured data of the battery pack in the current state collected by the sensor. In this example, the battery thermal management system to which the battery pack belongs manages the current working state of the battery pack, stores the current state of the battery pack, and sends the current state of the battery pack to the vehicle-mounted controller when receiving the identification instruction of the vehicle-mounted controller. The vehicle-mounted controller obtains the current state of the battery pack. The sensor is connected to the battery pack and the vehicle-mounted controller respectively, collects the measured data of the battery pack in the current state, and sends the measured data to the vehicle-mounted controller. The vehicle-mounted controller obtains the measured data of the battery pack in the current state. In this example, the current state of the battery pack includes a state of not entering a cooling state, a state of entering the cooling state and a state of exiting the cooling state. The state of not entering the cooling state refers to the state before the battery pack enters the cooling state. The state of entering the cooling state refers to the state of cooling the battery pack. The state of exiting the cooling state refers to the state of stopping cooling the battery pack. ​

[0056] In the example, the current state is determined based on the temperature of the battery pack. For example, when the temperature of the battery pack is lower than a first preset threshold a, the battery thermal management system determines that the current state of the battery pack is not entering the cooling state. When the temperature of the battery pack is monitored to be higher than the first preset threshold a, the battery thermal management system determines that the current state of the battery pack is entering the cooling state to cool the battery pack, improve the service life of the battery pack, and reduce the risk caused by the excessively high temperature of the battery pack. When the temperature of the battery pack is monitored to be lower than a second preset threshold b, the battery thermal management system determines that the current state of the battery pack is exiting the cooling state, and the cooling and temperature reduction process of the battery pack is not needed. Understandably, if the temperature of the battery pack is lower than the first preset threshold a, it indicates that the battery pack does not need to be cooled, and at this time, the battery pack is in the state of not entering the cooling state. If the temperature of the battery pack is higher than the first preset threshold a, it indicates that the temperature of the battery pack is excessively high, and the battery pack needs to be cooled and temperature-reduced, and the current state of the battery pack is determined to be converted from the state of not entering the cooling state to the state of entering the cooling state. If the temperature of the battery pack is monitored to be lower than the second preset threshold b, it indicates that the temperature of the battery pack is reduced to the normal working level, and the current state of the battery pack is determined to be converted from the state of entering the cooling state to the state of exiting the cooling state. In the example, the cold plate is laid at the bottom of the battery pack. When the current state of the battery pack is converted from the state of not entering the cooling state to the state of entering the cooling state, the vehicle-mounted controller starts the cold plate to cool and temperature-reduce the battery pack. When the current state of the battery pack is converted from the state of entering the cooling state to the state of exiting the cooling state, the vehicle-mounted controller controls the cold plate to stop cooling and temperature-reducing the battery pack.

[0057] In the example, the low-temperature power limit value refers to the power limit value corresponding to the battery pack at a lower temperature. The high-temperature power limit value refers to the power limit value corresponding to the battery pack at a higher temperature. Understandably, because the temperatures of different parts of the battery pack are not the same, at the same time, the battery pack corresponds to a low-temperature power limit value and a high-temperature power limit value.

[0058] As an example, in step S102, the vehicle-mounted controller processes the measured data of the battery pack in the current state to determine the low-temperature power limit value and the high-temperature power limit value of the battery pack in the current state. For example, the measured data includes but is not limited to the temperature data corresponding to each cell in the battery pack. The vehicle-mounted controller obtains the temperature data corresponding to each cell in the battery pack in the current state, filters the temperature data corresponding to each cell, determines the lowest temperature data and the highest temperature data among all the temperature data in the current state, processes the lowest temperature data to determine the power corresponding to the lowest temperature data, and determines the power corresponding to the lowest temperature data as the low-temperature power limit value corresponding to the battery pack in the current state; processes the highest temperature data to determine the power corresponding to the highest temperature data, and determines the power corresponding to the highest temperature data as the high-temperature power limit value corresponding to the battery pack in the current state. Understandably, when the temperature is too high or too low, the charging and discharging performance of the battery pack will decrease to a certain extent. Determining the low-temperature power limit value and the high-temperature power limit value of the battery pack can facilitate subsequent comparison of the low-temperature power limit value and the high-temperature power limit value to determine the smaller power limit value, which is more accurate and convenient. In this example, the current state of the battery pack is taken into account, and the low-temperature power limit value and the high-temperature power limit value corresponding to the battery pack in different current states can be accurately determined based on the measured data corresponding to the current state.

[0059] wherein the target power limit value refers to the smallest power limit value of the battery pack in the current state.

[0060] As an example, in step S103, the vehicle-mounted controller determines the smaller value between the low-temperature power limit value and the high-temperature power limit value in the current state as the target power limit value of the battery pack in the current state. Understandably, since different cells inside the battery pack and different parts of the same cell will generate different temperatures during the operation of the battery pack in the current state, different temperatures correspond to different power limit values. In order to protect the life of the battery pack and reduce the safety risk of the battery pack, it is necessary to identify the power short board of the battery pack during charging and discharging, i.e., to determine the smallest power limit value among different power limit values and determine the smallest power limit value as the target power limit value. In this example, the vehicle-mounted controller determines the smaller value between the low-temperature power limit value and the high-temperature power limit value at each moment in the current state as the target power limit value corresponding to the battery pack at each moment in the current state. Understandably, when the temperature is too high or too low, the charging and discharging performance of the battery pack is relatively low. Therefore, the smallest power limit value corresponding to the battery pack in the current state when the temperature is too high or too low is determined as the target power limit value to limit the power during the operation of the battery pack in the current state, thereby avoiding excessive charging power of the battery pack and effectively protecting the life and safety performance of the battery pack.

[0061] In this example, the low-temperature power limit and high-temperature power limit corresponding to the battery pack in the current state are compared to determine the smaller value of the two. This can more accurately determine the power shortcoming of the battery pack in the current state, that is, determine the target power limit corresponding to the battery pack, and achieve the purpose of more accurately determining the minimum power limit of the battery pack.

[0062] As an example, in step S104, after determining the target power limit for the current state, the onboard controller controls the charge and discharge power of each battery cell in the battery pack to not exceed the target power limit for the current state. In this example, controlling the battery pack to operate based on the target power limit for the current state can avoid the risk of battery life reduction and safety risks caused by exceeding the battery pack's charge and discharge capabilities, effectively improving the battery pack's operating performance and safety.

[0063] In this embodiment, based on the current state of the battery pack, the low-temperature power limit and high-temperature power limit corresponding to the battery pack in different current states can be determined more accurately. By comparing the low-temperature power limit and high-temperature power limit corresponding to the battery pack in the current state and determining the smaller value of the two, the target power limit corresponding to the battery pack in the current state can be determined more accurately. Controlling the battery pack to operate based on the target power limit in the current state can avoid the risk of reduced battery life and safety risks caused by the battery pack exceeding its charge and discharge capabilities, and can effectively improve the operating performance and safety performance of the battery pack. This method takes into account the current state of the battery pack and the measured data corresponding to the current state, compares the low-temperature power limit and high-temperature power limit corresponding to the current state, and determines the target power limit corresponding to the current state. It can more accurately determine the minimum power limit of the battery pack and has high application value.

[0064] In one embodiment, the measured data includes a minimum top temperature and a maximum top temperature.

[0065] The minimum top temperature refers to the lowest top temperature data corresponding to the battery pack in the current state. The maximum top temperature refers to the highest top temperature data corresponding to the battery pack in the current state. In this embodiment, a sensor is installed on the top of the battery cell of the battery pack to obtain the top temperature data corresponding to each moment of the battery pack being installed.

[0066] In one embodiment, if Figure 2 As shown, step S102, i.e., determining the low-temperature power limit and the high-temperature power limit of the battery pack based on the current state and measured data, includes:

[0067] S201: Determine a low-temperature power limit of the battery pack based on the current state of the battery pack, the lowest top temperature, and a preset temperature difference;

[0068] S202: determining a high-temperature power limit value of the battery pack based on the highest top temperature of the battery pack.

[0069] The preset temperature difference is a temperature difference pre-stored in the system database and used for determining the low-temperature power limit value of the battery pack.

[0070] As an example, in step S201, the vehicle-mounted controller processes the lowest top temperature corresponding to the current state and the preset temperature difference pre-stored in the system database to obtain the low-temperature power limit value of the battery pack in the current state. For example, the vehicle-mounted controller performs screening processing on the top temperature data in the current state to obtain the lowest top data of the battery pack in the current state, and performs analysis processing on the lowest top data and the pre-stored preset temperature difference to obtain the low-temperature power limit value of the battery pack in the current state. In this example, a two-dimensional mapping relationship table between temperature data and power limit values is pre-stored in the system database, the vehicle-mounted controller performs analysis processing on the lowest top data and the pre-stored preset temperature difference to obtain the temperature data corresponding to the battery pack, and queries the two-dimensional mapping relationship table pre-stored in the system database according to the obtained temperature data to determine the corresponding low-temperature power limit value. In this example, the current state of the battery pack is taken into account, and the low-temperature power limit value of the battery pack can be accurately determined according to the lowest top temperature corresponding to the current state and the preset temperature difference.

[0071] As an example, in step S202, the vehicle-mounted controller obtains the highest top temperature of the battery pack in each current state, and performs analysis processing on the highest top temperature of the battery pack in each current state to obtain the high-temperature power limit value of the battery pack in each current state. In this example, the vehicle-mounted controller queries the two-dimensional mapping relationship table between temperature data and power limit values pre-stored in the system database according to the highest top temperature in each current state to determine the high-temperature power limit value corresponding to the highest top temperature in each current state. In this example, the vehicle-mounted controller obtains all temperature data corresponding to each moment in the current state of the battery pack collected by at least one sensor connected to the top of the battery pack, screens all the temperature data to obtain the highest temperature data, i.e., the highest top temperature. In this example, at least one first sensor is connected to the top of at least one battery cell to collect at least one temperature data of the top of the battery pack. Understandably, since the charging power of different parts of each battery cell in the battery pack is different, the temperature data of different parts of each battery cell is also different. In this example, due to the limitation of assembly process, the cold plate is laid at the bottom of the battery pack, and the bottom of the battery pack is cooled first when the battery pack is cooled, and the top of the battery pack is usually higher in temperature than the bottom. Therefore, the high-temperature power limit value of the battery pack in each current state can be accurately determined according to the highest top temperature in each current state.

[0072] In this embodiment, the current state of the battery pack is considered, and the low-temperature power limit of the battery pack can be determined more accurately. According to the highest top temperature of the battery pack in each current state, the high-temperature power limit of the battery pack in each current state can be determined more accurately.

[0073] In an embodiment, the measured data further includes a measured remaining capacity.

[0074] The measured remaining capacity refers to the remaining capacity of the battery pack detected in real time in the current state.

[0075] In another embodiment, as shown in FIG. 1, step S102, i.e., determining the low-temperature power limit and the high-temperature power limit of the battery pack based on the current state and the measured data, further includes: Figure 3

[0076] S301: determining the low-temperature power limit of the battery pack based on the current state of the battery pack, the lowest top temperature, the measured remaining capacity, and a preset temperature difference;

[0077] S302: determining the high-temperature power limit of the battery pack based on the highest top temperature of the battery pack and the measured remaining capacity.

[0078] As an example, in step S301, the vehicle-mounted controller processes the corresponding lowest top temperature, the measured remaining capacity, and the preset temperature difference in the current state to obtain the low-temperature power limit of the battery pack in the current state. In this example, a three-dimensional mapping relationship table between temperature data, remaining capacity, and power limit is pre-stored in the system database. The vehicle-mounted controller analyzes and processes the lowest top data and the pre-stored preset temperature difference to obtain the corresponding temperature data of the battery pack. According to the processed temperature data and the measured remaining capacity, the three-dimensional mapping relationship table pre-stored in the system database is queried to determine the low-temperature power limit corresponding to the current state. In this example, the current state of the battery pack and the measured remaining capacity of the battery pack are considered, and the low-temperature power limit of the battery pack can be determined more accurately.

[0079] As an example, in step S302, the vehicle-mounted controller obtains the highest top temperature and the measured remaining capacity of the battery pack in each current state, and analyzes and processes the highest top temperature and the measured remaining capacity of the battery pack in each current state to obtain the high-temperature power limit of the battery pack in each current state. In this example, the vehicle-mounted controller queries a three-dimensional mapping relationship table between temperature data, remaining capacity, and power limit pre-stored in the system database according to the highest top temperature in each current state, and can more accurately determine the high-temperature power limit corresponding to the highest top temperature and the measured remaining capacity in each current state.

[0080] ​In this embodiment, the current state of the battery pack and the measured remaining power of the battery pack are considered, and the low-temperature power limit and the high-temperature power limit of the battery pack can be determined more accurately.

[0081] In an embodiment, as shown in FIG. 3, step S301 of determining the low-temperature power limit of the battery pack based on the current state of the battery pack, the lowest top temperature, the measured remaining power, and the preset temperature difference includes: Figure 4

[0082] S401: determining a first power limit based on the lowest top temperature and the measured remaining power of the battery pack;

[0083] S402: determining a second power limit of the battery pack based on the lowest top temperature, the measured remaining power, and the preset temperature difference of the battery pack;

[0084] S403: determining the low-temperature power limit of the battery pack based on the current state of the battery pack, the first power limit, and the second power limit.

[0085] The first power limit refers to the power limit of the battery pack determined based on the lowest top temperature.

[0086] As an example, in step S401, the vehicle-mounted controller obtains the lowest top temperature and the measured remaining power of the battery pack under each current state, processes the lowest top temperature and the measured remaining power under each current state, obtains the power limit corresponding to the lowest top temperature and the measured remaining power under each current state, and determines the power limit as the first power limit of the battery pack under each current state. For example, the vehicle-mounted controller can query a three-dimensional mapping relationship table between the temperature data, the measured remaining power, and the power limit pre-stored in the system database according to the lowest top temperature and the measured remaining power of the battery pack under the current state, determine the first power limit corresponding to the lowest top temperature and the measured remaining power of the battery pack under the current state, and be more convenient and fast. In this example, the current state includes but is not limited to not entering the cooling state, entering the cooling state, and exiting the cooling state.

[0087] The second power limit refers to the power limit of the battery pack determined based on the lowest top temperature and the preset temperature difference.

[0088] ​As an example, in step S402, the vehicle-mounted controller acquires the lowest top temperature and the measured residual capacity of the battery pack in each current state, acquires the preset temperature difference stored in the system database, processes the lowest top temperature, the measured residual capacity and the preset temperature difference in each current state, obtains the power limit value corresponding to the lowest top temperature, the measured residual capacity and the preset temperature difference in each current state, and determines the power limit value as the second power limit value of the battery pack in each current state. For example, the vehicle-mounted controller determines the lowest temperature data of the battery pack in the current state according to the lowest top temperature and the preset temperature difference, queries the three-dimensional mapping relationship table between the temperature data, the residual capacity and the power limit value pre-stored in the system database according to the lowest temperature data of the battery pack in the current state and the measured residual capacity, and determines the second power limit value corresponding to the lowest temperature data of the battery pack in the current state and the measured residual capacity in the current state. In the example, the lowest temperature data of the battery pack in the current state is determined according to the lowest top temperature and the preset temperature difference, which is used to represent the lowest temperature of the whole battery pack, so as to facilitate the determination of the second power limit value from the three-dimensional whole battery pack. In the example, the current state includes but is not limited to not entering the cooling state, entering the cooling state and exiting the cooling state.

[0089] As an example, in step S403, the vehicle-mounted controller processes the first power limit value in the current state and the second power limit value in the current state according to the current state of the battery pack, and obtains the low-temperature power limit value of the battery pack in the current state. For example, the vehicle-mounted controller compares the first power limit value in the current state and the second power limit value in the current state, and determines the smaller power limit value as the low-temperature power limit value of the battery pack in the current state.

[0090] In the embodiment, the first power limit value of the top of the battery pack can be accurately determined based on the lowest top temperature and the measured residual capacity of the battery pack, and the second power limit value of the battery pack under the low-temperature condition can be accurately determined from the three-dimensional whole battery pack based on the preset temperature difference, the lowest top temperature and the measured residual capacity.

[0091] In an embodiment, as shown in Figure 5 Step S402, i.e., determining the second power limit value of the battery pack based on the lowest top temperature, the measured residual capacity and the preset temperature difference of the battery pack, includes:

[0092] S501: determining the lowest bottom temperature of the battery pack based on the lowest top temperature and the preset temperature difference;

[0093] S502: determining the second power limit value of the battery pack based on the lowest bottom temperature and the measured residual capacity of the battery pack.

[0094] The lowest bottom temperature refers to the lowest temperature of the bottom of the battery pack in the current state.

[0095] As an example, in step S501, the vehicle-mounted controller performs difference processing on the lowest top temperature in the current state and the preset temperature difference to obtain the lowest bottom temperature in the current state. In this example, for the lowest top temperature in the current state and the preset temperature difference , the vehicle-mounted controller performs difference processing on the lowest top temperature in the current state and the preset temperature difference to obtain the lowest bottom temperature in the current state as follows: Understandably, the preset temperature difference is used to represent the maximum temperature difference between the top and bottom of the battery pack. If the lowest top temperature corresponding to the top of the battery pack is used to perform difference processing on the preset temperature difference, the bottom temperature of the battery pack with the largest difference from the lowest top temperature can be obtained, and the bottom temperature of the battery pack with the largest difference is the lowest bottom temperature.

[0096] As an example, in step S502, the vehicle-mounted controller analyzes and processes the lowest bottom temperature of the battery pack in the current state and the measured remaining capacity to determine a second power limit value corresponding to the lowest bottom temperature and the measured remaining capacity in the current state. For example, the vehicle-mounted controller queries a three-dimensional mapping relationship table between temperature data, measured remaining capacity, and power limit value pre-stored in the system database according to the lowest bottom temperature in the current state and the remaining capacity of the battery pack to determine a power limit value corresponding to the lowest bottom temperature and the remaining capacity of the battery pack in the current state, and determines the power limit value as the second power limit value. Understandably, due to the limitations of assembly process, the cold plate is laid on the bottom of the battery pack, and the bottom of the battery pack is cooled first when the battery pack is cooled, and the top of the battery pack is usually higher in temperature than the bottom. In the current state, the highest top temperature is usually not lower than the highest bottom temperature, so in each current state, the lowest bottom temperature corresponding to the battery pack can accurately reflect the lowest temperature of the battery pack in the three-dimensional whole package, and the second power limit value in the current state can be accurately determined from the three-dimensional whole package of the battery pack according to the lowest bottom temperature of the battery pack in the current state and the measured remaining capacity in the current state. In this example, the current state includes but is not limited to not entering the cooling state, entering the cooling state, and exiting the cooling state.

[0097] In this embodiment, the lowest bottom temperature corresponding to the battery pack in the current state is determined according to the lowest top temperature in the current state and the preset temperature difference, and the second power limit value corresponding to the battery pack in the current state can be accurately determined from the three-dimensional whole package based on the lowest bottom temperature corresponding to the battery pack in the current state and the measured remaining capacity.

[0098] In an embodiment, the step S403 of determining the low-temperature power limit of the battery pack based on the current state of the battery pack, the first power limit and the second power limit comprises:

[0099] S4031: if the current state is not entering the cooling state, determining the low-temperature power limit of the battery pack as the first power limit;

[0100] S4032: if the current state is that the time length of entering the cooling state is less than the first time length, determining the low-temperature power limit of the battery pack to be transitioned from the first power limit to the second power limit;

[0101] S4033: if the current state is that the time length of entering the cooling state is greater than or equal to the first time length, determining the low-temperature power limit of the battery pack as the second power limit;

[0102] S4034: if the current state is that the time length of exiting the cooling state is less than the second time length, determining the low-temperature power limit of the battery pack to be transitioned from the second power limit to the first power limit;

[0103] S4035: if the current state is that the time length of exiting the cooling state is greater than or equal to the second time length, determining the low-temperature power limit of the battery pack as the first power limit.

[0104] As an example, in the step S4031, the vehicle-mounted controller determines the first power limit as the low-temperature power limit of the battery pack when determining that the battery pack is not entering the cooling state. In this example, the vehicle-mounted controller obtains the lowest temperature of the battery pack when the battery pack is not entering the cooling state, and determines the first power limit based on the lowest temperature, and determines the first power limit as the low-temperature power limit of the battery pack at each moment when the battery pack is not entering the cooling state. Understandably, when the battery pack is not entering the cooling state, the cold plate laid at the bottom of the battery pack is not working, and the temperature difference between the top and the bottom of the battery pack is small, at this time, the lowest top temperature of the battery pack can represent the lowest temperature of the battery pack in the whole three-dimensional package, and the first power limit determined based on the lowest bottom temperature can be determined as the low-temperature power limit when the current state is not entering the cooling state, which can accurately determine the low-temperature power limit of the battery pack when the battery pack is not entering the cooling state in the whole three-dimensional package.

[0105] In the formula, the first time length is the time length between the time when the battery pack enters the cooling state and the time when the maximum temperature difference occurs. The maximum temperature difference refers to the maximum difference between the temperature of the top and the bottom of the battery pack.

[0106] As an example, in step S4032, when the vehicle-mounted controller determines that the current state of the battery pack is entering the cooling state and the duration of entering the cooling state is less than the first duration, the vehicle-mounted controller determines the low-temperature power limit value of the battery pack at each time point in the time period when the duration of entering the cooling state is less than the first duration according to the linear relationship of the first power limit value to the second power limit value relative to the first duration. In this example, the linear relationship of the first power limit value to the second power limit value relative to the first duration is: . In the time period when the duration of entering the cooling state is less than the first duration, the vehicle-mounted controller controls the low-temperature power limit value corresponding to each time point to be: , where t is the time point in the time period when the duration of entering the cooling state is less than the first duration, 0≤t<1, and 0 It can be understood that, since the power limit value of the battery pack is related to the temperature of the battery pack, the power limit value will change with the temperature, and when the battery pack is not in the cooling state, the low-temperature power limit value of the battery pack is the first power limit value. When the battery pack is in the cooling state, the low-temperature power limit value gradually increases until the maximum temperature difference between the bottom and the top of the battery pack is reached, corresponding to the second power limit value. Therefore, when the battery pack is in the cooling state, the low-temperature power limit value of the battery pack is between the first power limit value and the second power limit value, and linearly transitions from the first power limit value to the second power limit value.

[0107] As an example, in step S4033, when the vehicle-mounted controller determines that the current state of the battery pack is entering the cooling state and the duration of entering the cooling state is greater than or equal to the first duration, the vehicle-mounted controller determines the low-temperature power limit value of the battery pack at each time point after the duration of entering the cooling state is greater than or equal to the first duration as the second power limit value. It can be understood that, when the battery pack enters the cooling state and reaches the first duration, the second power limit value is reached. After the duration of entering the cooling state of the battery pack is greater than or equal to the first duration, the maximum temperature difference between the bottom and the top of the battery pack is reached, i.e., the overall temperature region of the battery pack is stable, and at this time, the second power limit value is maintained as the low-temperature power limit value of the battery pack.

[0108] where the second duration is the duration from the time point when the battery pack exits the cooling state to the time point when the minimum temperature difference is generated. The minimum temperature difference refers to the minimum difference between the temperature of the top and the bottom of the battery pack.

[0109] ​​​​​​As an example, in step S4034, when the onboard controller determines that the current state of the battery pack is exiting the cooling state and the duration of exiting the cooling state is less than the second duration, the onboard controller determines the low-temperature power limit value of the battery pack at each moment after exiting the cooling state and before reaching the second duration according to the linear relationship from the second power limit value to the first power limit value relative to the second duration. In this example, the second power limit value is To the first power limit Relative to the second duration The linear relationship is: When the battery pack is in the exit cooling state for a period of time that is less than the second period of time, the vehicle controller controls the low-temperature power limit corresponding to each moment to be: - ,in, The battery pack exits the cooling state and the first time within the time period that does not reach the second time period moments, 0≤ ≤ . It can be understood that, during the period when the battery pack exits the cooling state and has not reached the second time period, the temperature difference between the top and bottom of the battery pack becomes smaller because the cold plate at the bottom of the battery pack stops working. Since the power limit of the battery pack is related to the temperature of the battery pack, when the temperature changes, the power limit will also change with the temperature. Moreover, since the battery pack exits the cooling state, the battery pack temperature increases relative to when it enters the cooling state. At this time, the low-temperature power limit of the battery pack decreases relative to the second power limit until the battery pack reaches the second time period. Therefore, when the battery pack has not exited the cooling state and is greater than or equal to the first time period, the low-temperature power limit of the battery pack is the second power limit. When the battery pack exits the cooling state and has not reached the second time period, the low-temperature power limit of the battery pack is between the second power limit and the first power limit, and transitions linearly from the first power limit to the second power limit.

[0110] As an example, in step S4035, after the onboard controller determines that the current state of the battery pack is exiting the cooling state and that the duration of the exit from the cooling state is greater than or equal to the second duration, the second power limit is determined as the low-temperature power limit at each moment after the battery pack has exited the cooling state for a duration greater than or equal to the second duration. Understandably, at the moment when the duration of the battery pack exiting the cooling state equals the second duration, the low-temperature power limit of the battery pack transitions to the second power limit. At this time, the temperature difference between the bottom and top of the battery pack reaches a minimum, and the temperature difference between the bottom and top of the battery pack tends to remain constant. The second power limit obtained from this transition is then determined as the low-temperature power limit at each moment after the duration of the battery pack exiting the cooling state is greater than or equal to the second duration.

[0111] In this embodiment, according to different current states of the battery pack and the first time length corresponding to the maximum temperature difference between the top and bottom of the battery pack and the second time length corresponding to the minimum temperature difference between the top and bottom of the battery pack, the purpose of accurately determining the low-temperature power limit of the battery pack from the three-dimensional whole package is achieved, which can overcome the defects of the existing power limit determination of the battery pack in two-dimensional plane, so as to more reliably and stably determine the target power limit corresponding to different current states of the battery pack according to the accurate low-temperature power limit.

[0112] In another embodiment, as shown in Figure 6 Before step S101, that is, before obtaining the current state and the measured data of the battery pack, the battery control method further comprises:

[0113] S601: testing the battery pack to obtain a top test temperature and a bottom test temperature of the battery pack;

[0114] S602: determining a maximum test temperature difference and a first time length corresponding to the maximum test temperature difference after the battery pack enters the cooling state, and determining a minimum test temperature difference and a second time length corresponding to the minimum test temperature difference after the battery pack exits the cooling state based on the top test temperature and the bottom test temperature;

[0115] S603: determining the maximum test temperature difference as a preset temperature difference, and storing the preset temperature difference, the first time length and the second time length.

[0116] The top test temperature refers to the temperature data of the top of the battery pack when the battery pack is tested. The bottom test temperature refers to the temperature data of the bottom of the battery pack when the battery pack is tested.

[0117] As an example, in step S601, when the vehicle-mounted controller tests the battery pack in the vehicle, the top temperature data corresponding to each moment is obtained through the sensors at different positions of the top of the battery cell in the battery pack, and the bottom temperature data corresponding to each moment is obtained through the sensors installed at different positions of the bottom of the battery cell in the battery pack. Understandably, due to the limitation of process assembly, only temperature sensors are installed at the top of the battery cell in the battery pack under the working state of the vehicle, and sensors cannot be installed at the bottom of the battery cell, therefore, when the battery pack is tested, sensors are temporarily installed at the bottom of the battery cell of the battery pack to obtain test data including the preset temperature difference, the first time length and the second time length. In this example, under the test condition of the battery pack, sensors are installed at the top of the battery cell of the battery pack for collecting the top test temperature, and sensors are temporarily installed at the bottom of the battery cell of the battery pack for collecting the bottom test temperature. The positions of the sensors arranged at the top of the battery cell correspond to a top test temperature at each moment. The positions of the temporarily installed sensors at the bottom of the battery cell correspond to a bottom test temperature at each moment.

[0118] The maximum test temperature difference refers to the maximum value of the temperature difference between the top and the bottom of the battery pack during the test of the battery pack. The minimum test temperature difference refers to the minimum value of the temperature difference between the top and the bottom of the battery pack during the test of the battery pack.

[0119] As an example, in step S602, after determining that the current state of the battery pack during the test is entering the cooling state, the vehicle-mounted controller calculates the difference between each top test temperature and each bottom test temperature corresponding to each battery cell until the maximum difference value is obtained, determines the maximum difference value as the maximum test temperature difference after the battery pack enters the cooling state, and determines the time length between the time when the battery pack enters the cooling state and the time when the maximum difference value is generated as the first time length corresponding to the maximum test temperature difference. After determining that the current state of the battery pack during the test is exiting the cooling state, the vehicle-mounted controller calculates the difference between each top test temperature and each bottom test temperature corresponding to each battery cell until the minimum difference value is obtained, determines the minimum difference value as the minimum test temperature difference after the battery pack exits the cooling state, and determines the time length between the time when the battery pack exits the cooling state and the time when the minimum difference value is generated as the second time length corresponding to the minimum test temperature difference. Understandably, after the battery pack enters the cooling state, the temperature reduction speed of the bottom of the battery cell is higher than that of the top of the battery cell because the bottom of the battery cell is laid on the cold plate, so the difference between the top test temperature and the bottom test temperature gradually increases until the maximum difference value is reached, and the difference between the top test temperature and the bottom test temperature is stable within the controllable range corresponding to the maximum difference value, so the maximum difference value is determined as the maximum test temperature difference after the battery pack enters the cooling state. After the battery pack exits the cooling state, the temperature reduction speed of the bottom of the battery cell gradually decreases because the cold plate of the bottom of the battery cell stops cooling, and the difference between the top test temperature and the bottom test temperature gradually decreases until the minimum difference value is reached, and the difference between the top test temperature and the bottom test temperature is stable within the controllable range corresponding to the minimum difference value, so the minimum difference value is determined as the minimum test temperature difference after the battery pack enters the cooling state. In the first time length and the second time length, the difference between the top test temperature and the bottom test temperature of the battery pack is constantly changing, and the changing difference value needs to correspond to different target power limit values to ensure the performance of the battery pack, so the first time length and the second time length need to be determined to more accurately determine the target power limit value of the battery pack corresponding to the changing difference value. In this example, according to the top test temperature and the bottom test temperature corresponding to each battery cell in the battery pack, the maximum test temperature difference after the battery pack enters the cooling state and the minimum test temperature difference after the battery pack exits the cooling state can be more accurately determined.

[0120] As an example, in step S603, the vehicle-mounted controller determines the maximum test temperature difference as the preset temperature difference, and stores the preset temperature difference, the first time length and the second time length in the system database, so as to determine the target power limit of the battery pack in different current states more accurately from the three-dimensional perspective of the whole pack according to the preset temperature difference, the first time length and the second time length.

[0121] In the embodiment, according to the top test temperature and the bottom test temperature of the battery cell obtained by testing the battery pack, the maximum test temperature difference between the top and the bottom of the battery pack after entering the cooling state and the first time length, and the minimum test temperature difference between the top and the bottom of the battery pack after exiting the cooling state and the second time length are determined, and the maximum test temperature difference is stored as the preset temperature difference, so as to more accurately determine the preset temperature difference, the first time length and the second time length of the battery pack from the three-dimensional perspective of the whole pack, and overcome the defect that the existing temperature difference can only be determined in the two-dimensional plane, so as to more accurately determine the target power limit of the battery pack from the three-dimensional perspective of the whole pack according to the preset temperature difference, the first time length and the second time length of the battery pack.

[0122] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0123] In an embodiment, a vehicle-mounted controller is provided, as shown in Figure 7 which includes a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the battery control method in the above embodiment when executing the computer program, for example Figure 1 S101-S104, or Figures 2 to 6 to avoid repetition, details are not repeated here.

[0124] In an embodiment, a battery control system is provided, which includes a sensor, a battery pack and the above vehicle-mounted controller, the sensor is connected to the battery pack and the vehicle-mounted controller respectively, and the battery pack is connected to the vehicle-mounted controller.

[0125] In the embodiment, the vehicle-mounted controller is connected with the battery pack, and is used for determining the low-temperature power limit value and the high-temperature power limit value of the battery pack according to the real-time acquired current state of the battery pack, determining the target power limit value of the battery pack in the current state as the smaller one of the low-temperature power limit value and the high-temperature power limit value, and controlling the battery pack to work based on the target power limit value of the battery pack in the current state, so that the working performance and safety performance of the battery pack can be effectively improved, and the application value is high.

[0126] In an embodiment, a vehicle is provided, which comprises the battery control system in the above embodiments.

[0127] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is taken as an example for illustration, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above.

[0128] The above-described embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A battery control method characterized by, The method comprises the following steps: obtaining a current state of a battery pack and measured data corresponding to the current state; determining a low-temperature power limit value and a high-temperature power limit value of the battery pack based on the current state and the measured data; the determination of the low-temperature power limit value of the battery pack comprises: determining a first power limit value based on a lowest top temperature of the battery pack and a measured remaining power; determining a lowest bottom temperature of the battery pack based on the lowest top temperature and a preset temperature difference; determining a second power limit value of the battery pack based on the lowest bottom temperature of the battery pack and the measured remaining power; determining the low-temperature power limit value of the battery pack based on the current state of the battery pack, the first power limit value and the second power limit value; determining the smaller one of the low-temperature power limit value and the high-temperature power limit value as a target power limit value of the battery pack; controlling the battery pack to work based on the target power limit value.

2. The battery control method according to claim 1, wherein The measured data comprises a lowest top temperature and a highest top temperature. The determination of the low-temperature power limit value and the high-temperature power limit value of the battery pack based on the current state and the measured data comprises: determining the low-temperature power limit value of the battery pack based on the current state of the battery pack, the lowest top temperature and the preset temperature difference; determining the high-temperature power limit value of the battery pack based on the highest top temperature of the battery pack.

3. The battery control method according to claim 2, wherein The measured data further comprises a measured remaining power. The determination of the low-temperature power limit value and the high-temperature power limit value of the battery pack based on the current state and the measured data further comprises: determining the low-temperature power limit value of the battery pack based on the current state of the battery pack, the lowest top temperature, the measured remaining power and the preset temperature difference; determining the high-temperature power limit value of the battery pack based on the highest top temperature of the battery pack and the measured remaining power.

4. The battery control method of claim 1, wherein, The determination of the low-temperature power limit value of the battery pack based on the current state of the battery pack, the first power limit value and the second power limit value comprises: if the current state is not entering a cooling state, determining the low-temperature power limit value of the battery pack as the first power limit value; if the current state is entering the cooling state for a time period less than a first time period, determining the low-temperature power limit value of the battery pack to transit from the first power limit value to the second power limit value; if the current state is entering the cooling state for a time period greater than or equal to the first time period, determining the low-temperature power limit value of the battery pack as the second power limit value; if the current state is exiting the cooling state for a time period less than a second time period, determining the low-temperature power limit value of the battery pack to transit from the second power limit value to the first power limit value; if the current state is exiting the cooling state for a time period greater than or equal to the second time period, determining the low-temperature power limit value of the battery pack as the first power limit value.

5. The battery control method according to claim 4, wherein Before the obtaining of the current state of the battery pack and the measured data, the battery control method further comprises: testing the battery pack to obtain a top test temperature and a bottom test temperature of the battery pack; determining a maximum test temperature difference after the battery pack enters the cooling state and a first time length corresponding to the maximum test temperature difference based on the top test temperature and the bottom test temperature, and determining a minimum test temperature difference after the battery pack exits the cooling state and a second time length corresponding to the minimum test temperature difference; determining the maximum test temperature difference as the preset temperature difference, and storing the preset temperature difference, the first time length and the second time length.

6. An in-vehicle controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor implements the battery control method according to any one of claims 1 to 5 when executing the computer program.

7. A battery control system characterized by comprising: The vehicle-mounted controller according to claim 6, wherein the battery pack is connected to the vehicle-mounted controller.

8. An automobile characterized by comprising: The battery control system according to claim 7.

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