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

Abstract

The invention discloses a battery control method, a vehicle-mounted controller, a battery control system and an automobile. The method comprises the following steps: acquiring a current state of a battery pack and actually 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 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; and controlling the battery pack to work based on the target power limit value. According to the method, the current state of the battery pack and the measured data corresponding to the current state are considered, the low-temperature power limit value and the high-temperature power limit value corresponding to the current state are compared, the target power limit value corresponding to the current state is determined, the minimum power limit value of the battery pack can be accurately determined, and the method has high application value.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a battery control method, a vehicle-mounted controller, a battery control system and a vehicle. Background Art

[0002] As the power capacity of battery packs in electric vehicles continues to increase, the heat generated by battery packs also increases. It is usually necessary to cool the battery pack to enhance the heat dissipation capacity of the battery pack. The current mainstream cooling method will cause a large temperature difference between the bottom and top of the battery pack, and the large temperature difference will lead to different charging and discharging capabilities between different cells and between different parts of the same cell. When driving under severe working conditions or fast charging in a high temperature environment, it is easy for individual positions of the battery pack to exceed the charging and discharging capacity, which will not only reduce the life of the battery pack, but also easily cause safety risks such as lithium plating in the negative electrode of the battery cell, reducing the working performance and safety performance of the battery pack.

[0003] Therefore, it is necessary to set a power limit for the battery pack and control each position of the battery pack to be below the power limit for charging and discharging, so as to increase the 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 cells 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 more accurately determine the power limit of the battery pack is a technical problem that needs to be solved urgently. Summary of the invention

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

[0005] A battery control method, comprising: Acquire the current state of the battery pack and measured data corresponding to the current state; 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; Determine the smaller value of the low temperature power limit and the high temperature power limit as the target power limit of the battery pack; Based on the target power limit, the battery pack is controlled to operate.

[0006] Preferably, the measured data includes the lowest top temperature and the highest top temperature; The determining, based on the current state and the measured data, a low temperature power limit value and a high temperature power limit value of the battery pack includes: Determining a low temperature power limit of the battery pack based on a current state of the battery pack, a minimum top temperature, and a preset temperature difference; A high temperature power limit of the battery pack is determined based on a maximum top temperature of the battery pack.

[0007] Preferably, the measured data also includes the measured remaining power; The determining, based on the current state and the measured data, a low temperature power limit value and a high temperature power limit value of the battery pack further includes: Determining a 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 a preset temperature difference; A high temperature power limit of the battery pack is determined based on the maximum top temperature of the battery pack and the measured remaining power.

[0008] Preferably, 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: Determining a first power limit value based on the lowest top temperature of the battery pack and the measured remaining power; determining a second power limit value of the battery pack based on the lowest top temperature of the battery pack, the measured remaining power, and a preset temperature difference; A low temperature power limit of the battery pack is determined based on a current state of the battery pack, the first power limit, and the second power limit.

[0009] Preferably, determining the second power limit of the battery pack based on the lowest top temperature of the battery pack, the measured remaining power and a preset temperature difference includes: Determining a minimum bottom temperature of the battery pack based on the minimum top temperature and the preset temperature difference; A second power limit value of the battery pack is determined based on the lowest bottom temperature of the battery pack and the measured remaining power.

[0010] Preferably, 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 includes: If the current state is not in the cooling state, determining the low temperature power limit value of the battery pack to be the first power limit value; If the duration of the current state entering the cooling state is less than the first duration, determining that the low temperature power limit of the battery pack is transitioned from the first power limit to the second power limit; If the duration of the current state entering the cooling state is greater than or equal to the first duration, determining the low temperature power limit value of the battery pack to be the second power limit value; If the duration of the current state exiting the cooling state is less than a second duration, determining that the low temperature power limit of the battery pack transitions from the second power limit to the first power limit; If the duration of the current state exiting the cooling state is greater than or equal to the second duration, the low temperature power limit value of the battery pack is determined to be the first power limit value.

[0011] Preferably, before obtaining the current state and measured data of the battery pack, the battery control method further includes: Testing a battery pack to obtain a top test temperature and a bottom test temperature of the battery pack; Based on the top test temperature and the bottom test temperature, determine a maximum test temperature difference after the battery pack enters a cooling state and a first duration corresponding to the maximum test temperature difference, and determine a minimum test temperature difference after the battery pack exits a cooling state and a second duration corresponding to the minimum test temperature difference; The maximum test temperature difference is determined as the preset temperature difference, and the preset temperature difference, the first time length, and the second time length are stored.

[0012] A vehicle-mounted controller comprises 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.

[0013] A battery control system comprises 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.

[0014] A car comprises the above-mentioned battery control system.

[0015] The above-mentioned battery control method, vehicle controller, battery control system and automobile can more accurately determine the low temperature power limit and high temperature power limit corresponding to the battery pack under different current states according to the current state of the battery pack. 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 more accurately determined. Controlling the battery pack to work 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 the charging and discharging capacity, and can effectively improve the working 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, determines the target power limit corresponding to the current state, and can more accurately determine the minimum power limit of the battery pack, which has high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0017] Figure 1 is a flow chart of a battery control method in one embodiment of the present invention; Figure 2 is another flow chart of a battery control method according to an embodiment of the present invention; Figure 3 is another flow chart of a battery control method according to an embodiment of the present invention; Figure 4 is another flow chart of a battery control method according to an embodiment of the present invention; Figure 5 is another flow chart of a battery control method according to an embodiment of the present invention; Figure 6 is another flow chart of a battery control method according to an embodiment of the present invention; Figure 7 Schematic diagram of a vehicle-mounted controller according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The battery control method provided by the embodiment of the present invention can be applied to an on-board controller in a vehicle to achieve the purpose of more accurately determining the power limit of a battery pack.

[0020] In one embodiment, if Figure 1 As shown, a battery control method is provided, which is applied in Figure 7 The vehicle controller in the example is used to illustrate the process, including the following steps: S101: Acquire the current state of the battery pack and measured data corresponding to the current state; S102: Determine a low temperature power limit and a high temperature power limit of the battery pack based on the current state and measured data; S103: Determine the smaller value of the low temperature power limit and the high temperature power limit as the target power limit of the battery pack; S104: Control the battery pack to operate based on the target power limit.

[0021] The current state refers to the current working state of the battery pack, and the measured data refers to the data of the battery pack in the current state.

[0022] As an example, in step S101, the on-board 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 and stores the current state of the battery pack. When the battery thermal management system receives the identification instruction from the on-board controller, it sends the current state of the battery pack to the on-board controller, and the on-board controller obtains the current state of the battery pack. The sensors are connected to the battery pack and the on-board controller respectively. The sensors collect the measured data of the battery pack in the current state and send the measured data to the on-board controller, and the on-board controller obtains the measured data of the battery pack in the current state. In this example, the current state of the battery pack includes not entering the cooling state, entering the cooling state, and exiting the cooling state. Among them, not entering the cooling state refers to the state before the battery pack enters the cooling state. Entering the cooling state refers to the state of cooling the battery pack. Exiting the cooling state refers to the state of stopping cooling the battery pack.

[0023] In this 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 the first preset threshold a, the battery thermal management system determines that the current state of the battery pack is not in the cooling state. When the temperature of the battery pack is detected to be higher than the first preset threshold a, the battery thermal management system determines that the current state of the battery pack is in the cooling state, so as to cool the battery pack, improve the life of the battery pack, and reduce the risk caused by the excessive temperature of the battery pack. When the temperature of the battery pack is detected to be lower than the second preset threshold b, the battery thermal management system determines that the current state of the battery pack is in the exit cooling state, and there is no need to cool the battery pack. Understandably, if the temperature of the battery pack is lower than the first preset threshold a, it indicates that there is no need to cool the battery pack. At this time, the battery pack is in the non-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 too high and the battery pack needs to be cooled. It is determined that the current state of the battery pack is converted from the non-cooling state to the cooling state. If the temperature of the battery pack is detected to be lower than the second preset threshold b, it indicates that the temperature of the battery pack is reduced to a normal working level, and it is determined that the current state of the battery pack is converted from the cooling state to the exit cooling state. In this example, a cold plate is laid flat on the bottom of the battery pack. When the current state of the battery pack changes from a non-cooling state to a cooling state, the on-board controller starts the cold plate to cool the battery pack. When the current state of the battery pack changes from a cooling state to an exiting cooling state, the on-board controller controls the cold plate to stop cooling the battery pack.

[0024] Among them, the low temperature power limit refers to the power limit corresponding to the battery pack at a lower temperature. The high temperature power limit refers to the power limit corresponding to the battery pack at a higher temperature. It can be understood that since 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 and a high temperature power limit.

[0025] As an example, in step S102, the on-board controller processes the measured data of the battery pack in the current state to determine the low-temperature power limit and high-temperature power limit 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 battery cell in the battery pack. The on-board controller obtains the temperature data corresponding to each battery cell in the battery pack in the current state, screens the temperature data corresponding to each battery 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, determines the power corresponding to the lowest temperature data, and determines the power corresponding to the lowest temperature data as the low-temperature power limit corresponding to the battery pack in the current state; processes the highest temperature data, determines the power corresponding to the highest temperature data, and determines the power corresponding to the highest temperature data as the high-temperature power limit corresponding to the battery pack in the current state. It can be understood that 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 and high-temperature power limit of the battery pack is more accurate and convenient, so as to directly compare the low-temperature power limit and the high-temperature power limit in the future and determine a smaller power limit. In this example, the current state of the battery pack is taken into consideration, and based on the measured data corresponding to the current state, the low-temperature power limit and high-temperature power limit corresponding to the battery pack in different current states can be determined more accurately.

[0026] The target power limit refers to the minimum power limit of the battery pack in the current state.

[0027] As an example, in step S103, the on-board controller determines the smaller value of the low-temperature power limit and the high-temperature power limit in the current state as the target power limit of the battery pack in the current state. It is understandable that, since different cells inside the battery pack and different parts of the same cell will generate different temperatures during operation in the current state, and different temperatures correspond to different power limits, in order to ensure the life of the battery pack and reduce the safety risks of the battery pack, it is necessary to identify the power short board of the battery pack during charging and discharging, that is, to determine the smallest power limit among different power limits, and determine the smallest power limit as the target power limit. In this example, the on-board controller determines the smaller value of the low-temperature power limit and the high-temperature power limit at each moment in the current state as the target power limit corresponding to the battery pack at each moment in the current state. It is understandable that when the temperature is too high or too low, the charging and discharging performance of the battery pack is low. The minimum power limit corresponding to the battery pack when the temperature is too high or too low in the current state is used as the target power limit to limit the power of the battery pack when it is working in the current state, thereby avoiding the battery pack's charging power from being too high, which can effectively ensure the life and safety performance of the battery pack.

[0028] In this example, the low-temperature power limit and the 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, thereby achieving the purpose of more accurately determining the minimum power limit of the battery pack.

[0029] As an example, in step S104, after determining the target power limit value in the current state, the onboard controller controls the charge and discharge power of each cell in the battery pack to be no higher than the target power limit value in the current state. In this example, controlling the battery pack to operate based on the target power limit value in the current state can avoid the risk of reduced battery life and safety risks caused by exceeding the charge and discharge capacity of the battery pack, and can effectively improve the working performance and safety performance of the battery pack.

[0030] In this embodiment, according to 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 the charging and discharging capacity, and can effectively improve the working 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.

[0031] In one embodiment, the measured data includes a minimum top temperature and a maximum top temperature.

[0032] The lowest top temperature refers to the lowest top temperature data corresponding to the battery pack in the current state. The highest 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 under each current installation.

[0033] 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 the measured data, includes: S201: Determine a low temperature power limit of the battery pack based on a current state of the battery pack, a minimum top temperature, and a preset temperature difference; S202: Determine a high temperature power limit of the battery pack based on the highest top temperature of the battery pack.

[0034] The preset temperature difference refers to the temperature difference pre-stored in the system database, which is used to determine the low temperature power limit of the battery pack.

[0035] As an example, in step S201, the onboard 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 corresponding to the battery pack in the current state. For example, the onboard controller screens the top temperature data in the current state to obtain the lowest top data of the battery pack in the current state, analyzes and processes 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, and the onboard controller analyzes and processes 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 processed 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 determined more accurately according to the lowest top temperature corresponding to the current state and the preset temperature difference.

[0036] As an example, in step S202, the onboard controller obtains the highest top temperature of the battery pack in each current state, analyzes and processes the highest top temperature of the battery pack in each current state, and obtains the high temperature power limit of the battery pack in each current state. In this example, the onboard controller queries the system database for a two-dimensional mapping relationship table pre-stored between temperature data and power limit values ​​according to the highest top temperature in each current state, and determines the high temperature power limit corresponding to the highest top temperature in each current state. In this example, the onboard controller obtains all temperature data corresponding to each moment of the battery pack in the current state collected by at least one sensor connected to the top of the battery pack, and screens all temperature data to obtain the highest temperature data, which is 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. It can be understood that 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 limitations of the assembly process, the cold plate is laid on the bottom of the battery pack. When cooling the battery pack, the bottom of the battery pack is cooled first. The top of the battery pack is generally at a higher temperature than the bottom. In the current state, the highest top temperature is generally not lower than the highest bottom temperature. Therefore, based on the highest top temperature in each current state, the high temperature power limit of the battery pack in each current state can be determined more accurately.

[0037] In this embodiment, the current state of the battery pack is taken into account, so the low-temperature power limit of the battery pack can be determined more accurately, and the high-temperature power limit of the battery pack in each current state can be determined more accurately based on the highest top temperature of the battery pack in each current state.

[0038] In one embodiment, the measured data also includes the measured remaining power.

[0039] The actual remaining power refers to the remaining power of the battery pack detected in real time under the current state.

[0040] In another embodiment, if Figure 3 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 the measured data, also includes: S301: determining a 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; S302: Determine a high temperature power limit of the battery pack based on the maximum top temperature of the battery pack and the measured remaining power.

[0041] As an example, in step S301, the on-board controller processes the lowest top temperature, the measured remaining power, and the preset temperature difference corresponding to the current state to obtain the low-temperature power limit corresponding to the battery pack in the current state. In this example, a three-dimensional mapping relationship table between temperature data, remaining power, and power limit is pre-stored in the system database. The on-board controller analyzes and processes the lowest top data and the pre-stored preset temperature difference to obtain the temperature data corresponding to the battery pack, and queries the three-dimensional mapping relationship table pre-stored in the system database based on the processed temperature data and the measured remaining power to determine the low-temperature power limit corresponding to the current state. In this example, taking into account the current state of the battery pack and the measured remaining power of the electromagnetic pack, the low-temperature power limit of the battery pack can be determined more accurately.

[0042] As an example, in step S302, the vehicle controller obtains the highest top temperature and the measured remaining power of the battery pack in each current state, analyzes and processes the highest top temperature and the measured remaining power of the battery pack in each current state, and obtains the high temperature power limit of the battery pack in each current state. In this example, the vehicle controller queries the system database pre-stored with a three-dimensional mapping relationship table between temperature data, remaining power and power limit 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 power in each current state.

[0043] In this embodiment, the current state of the battery pack and the actually measured remaining power of the battery pack are taken into consideration, so that the low temperature power limit and the high temperature power limit of the battery pack can be determined more accurately.

[0044] In one embodiment, if Figure 4 As shown, step S301, i.e., 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: S401: Determine a first power limit value based on the lowest top temperature of the battery pack and the measured remaining power; S402: Determine a second power limit value of the battery pack based on the lowest top temperature of the battery pack, the measured remaining power, and the preset temperature difference; S403: Determine a 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.

[0045] The first power limit refers to the power limit of the battery pack determined based on the lowest top temperature.

[0046] As an example, in step S401, the vehicle controller obtains the lowest top temperature and the measured remaining power of the battery pack in each current state, processes the lowest top temperature and the measured remaining power in each current state, obtains the power limit value corresponding to the lowest top temperature and the measured remaining power in each current state, and determines the power limit value as the first power limit value of the battery pack in each current state. For example, the vehicle controller can query the three-dimensional mapping relationship table between the temperature data, the measured remaining power and the power limit value pre-stored in the system database according to the lowest top temperature and the measured remaining power of the battery pack in the current state, and determine the first power limit value corresponding to the lowest top temperature and the measured remaining power of the battery pack in the current state, which is relatively convenient and quick. 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.

[0047] The second power limit refers to the power limit of the battery pack determined based on the lowest top temperature and a preset temperature difference.

[0048] As an example, in step S402, the onboard controller obtains the lowest top temperature and the measured remaining power of the battery pack in each current state, and obtains the preset temperature difference stored in the system database, processes the lowest top temperature, the measured remaining power and the preset temperature difference in each current state, obtains the power limit value corresponding to the lowest top temperature, the measured remaining power 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 onboard 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 remaining power and the power limit value pre-stored in the system database according to the lowest temperature data and the measured remaining power of the battery pack in the current state, and determines the second power limit value corresponding to the lowest temperature data and the measured remaining power of the battery pack in the current state in the current state. In this 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, and the lowest temperature data is used to characterize the lowest temperature of the entire battery pack, so as to facilitate the determination of the second power limit value from the three-dimensional perspective of the entire battery pack. 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.

[0049] As an example, in step S403, the onboard 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 to obtain the low temperature power limit value of the battery pack in the current state. For example, the onboard controller compares the first power limit value in the current state with 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.

[0050] In this embodiment, based on the lowest top temperature of the battery pack and the measured remaining power, the first power limit at the top of the battery pack can be determined more accurately. Based on the preset temperature difference, the lowest top temperature and the measured remaining power, the second power limit under low temperature conditions corresponding to the battery pack can be determined more accurately from the three-dimensional perspective of the entire battery pack.

[0051] In one embodiment, if Figure 5 As shown, step S402, i.e. determining a second power limit of the battery pack based on the lowest top temperature of the battery pack, the measured remaining power and the preset temperature difference, includes: S501: Determine the lowest bottom temperature of the battery pack based on the lowest top temperature and a preset temperature difference; S502: Determine a second power limit value of the battery pack based on the lowest bottom temperature of the battery pack and the measured remaining power.

[0052] The minimum bottom temperature refers to the lowest temperature at the bottom of the battery pack in the current state.

[0053] As an example, in step S501, the vehicle 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. and preset temperature difference The vehicle controller sets the lowest top temperature in the current state and preset temperature difference Perform difference processing to obtain the lowest bottom temperature under the current state for: Understandably, the preset temperature difference is used to characterize the maximum temperature difference between the top and bottom of the battery pack. If the preset temperature difference is processed by using the lowest top temperature corresponding to the top of the battery pack, 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.

[0054] As an example, in step S502, the vehicle controller analyzes and processes the lowest bottom temperature and the measured remaining power of the battery pack in the current state, and determines the second power limit value corresponding to the lowest bottom temperature and the measured remaining power in the current state. For example, the vehicle controller queries the three-dimensional mapping relationship table between the temperature data, the measured remaining power and the power limit value pre-stored in the system database according to the lowest bottom temperature and the remaining power of the battery pack in the current state, determines the power limit value corresponding to the lowest bottom temperature and the remaining power of the battery pack in the current state, and determines the power limit value as the second power limit value. Understandably, due to the limitation of the assembly process, the cold plate is laid at the bottom of the battery pack. When cooling the battery pack, the bottom of the battery pack is cooled first. The top of the battery pack is usually at a higher temperature than the bottom. In the current state, the highest top temperature is usually not lower than the highest bottom temperature. Therefore, in each current state, the lowest bottom temperature corresponding to the battery pack can more accurately reflect the lowest temperature of the battery pack in the three-dimensional plane of the whole pack. According to the lowest bottom temperature of the battery pack in the current state and the measured remaining power in the current state, the second power limit value in the current state can be more accurately determined from the three-dimensional plane of the whole pack of the battery pack. 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.

[0055] In this embodiment, the minimum bottom temperature of the battery pack in the current state is determined according to the minimum top temperature in the current state and the preset temperature difference. Based on the minimum bottom temperature of the battery pack in the current state and the measured remaining power, the second power limit corresponding to the battery pack in the current state can be more accurately determined from the three-dimensional perspective of the entire pack.

[0056] In one embodiment, step S403, i.e., 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, includes: S4031: If the current state is not in the cooling state, determine the low temperature power limit of the battery pack to be the first power limit; S4032: If the duration of the current state entering the cooling state is less than the first duration, determining that the low temperature power limit of the battery pack is transitioned from the first power limit to the second power limit; S4033: If the current state is a cooling state for a time period greater than or equal to the first time period, determining the low temperature power limit of the battery pack to be a second power limit; S4034: If the duration of the current state exiting the cooling state is less than the second duration, determining that the low temperature power limit of the battery pack transitions from the second power limit to the first power limit; S4035: If the duration of the current state exiting the cooling state is greater than or equal to the second duration, determine that the low temperature power limit of the battery pack is the first power limit.

[0057] As an example, in step S4031, when the onboard controller determines that the battery pack is in a non-cooling state, the first power limit is determined as the low temperature power limit of the battery pack. In this example, when the onboard controller determines that the battery pack is not in a cooling state, it obtains the lowest temperature of the battery pack in the non-cooling state, 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 in a cooling state. It can be understood that when the battery pack is not in a cooling state, the cold plate laid on the bottom of the battery pack is not working, and the temperature difference between the top and 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 three-dimensional space of the entire pack. The first power limit determined based on the lowest bottom temperature is determined as the low temperature power limit when the current state is not in a cooling state, and the low temperature power limit of the battery pack when it is not in a cooling state can be determined more accurately in the three-dimensional space of the entire pack.

[0058] The first time duration is the time duration from when the battery pack enters the cooling state to when the maximum temperature difference is generated. The maximum temperature difference refers to the maximum temperature difference between the top and bottom of the battery pack.

[0059] As an example, in step S4032, when the vehicle controller determines that the current state is the cooling state and the duration of entering the cooling state is less than the first duration, the low temperature power limit of the battery pack at each moment in the time period when the duration of entering the cooling state is less than the first duration is determined according to the linear relationship between the first power limit value and the second power limit value relative to the first duration. In this example, the first power limit value To the second power limit Relative to the first duration The linear relationship is: , when the battery pack enters the cooling state for a period of time that is less than the first period, the low-temperature power limit corresponding to each moment controlled by the on-board controller is: + ,in, The time period during which the battery pack enters the cooling state is less than the first time period. Moments, 0≤ ≤ . Understandably, 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. When the battery pack does not enter the cooling state, the low-temperature power limit of the battery pack is the first power limit. When the battery pack enters the cooling state, the low-temperature power limit gradually increases because the battery pack is cooled down until the maximum temperature difference is reached between the bottom and the top of the battery pack, corresponding to the second power limit. Therefore, when the battery pack enters the cooling state, the low-temperature power limit of the battery pack is between the first power limit and the second power limit, and linearly transitions from the first power limit to the second power limit.

[0060] As an example, in step S4033, when the onboard controller determines that the current state of the battery pack is in the cooling state and the duration of entering the cooling state is greater than or equal to the first duration, the second power limit is determined as the low temperature power limit of the battery pack at each moment after the duration of entering the cooling state is greater than or equal to the first duration. It can be understood that the moment when the battery pack enters the cooling state and reaches the first duration corresponds to the second power limit, and after the duration of the battery pack entering the cooling state is greater than or equal to the first duration, the bottom and top of the battery pack reach the maximum temperature difference, that is, the overall temperature area of ​​the battery pack is stable, and at this time, the second power limit is maintained as the low temperature power limit of the battery pack.

[0061] The second time duration is the time duration from when the battery pack exits the cooling state to when the minimum temperature difference is generated. The minimum temperature difference refers to the minimum temperature difference between the top and bottom of the battery pack.

[0062] As an example, in step S4034, when the onboard controller determines that the current state of the battery pack is the exit cooling state and the duration of the exit 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 the battery pack exits 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 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 during the period of time not reaching the second time length Moments, 0≤ ≤ . Understandably, during the period when the battery pack exits the cooling state and does not reach the second time period, since the cold plate at the bottom of the battery pack stops working, the temperature difference between the top and the bottom of the battery pack becomes smaller. 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 entering 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 does not exit 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 does not reach 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 linearly transitions from the first power limit to the second power limit.

[0063] As an example, in step S4035, after determining that the current state of the battery pack is the exit cooling state and the duration of the exit cooling state is greater than or equal to the second duration, the on-board controller determines the second power limit 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. It can be understood that at the moment when the duration of the battery pack exiting the cooling state is equal to the second duration, the low temperature power limit of the battery pack transitions to the second power limit, at which time the bottom and top of the battery pack reach the minimum temperature difference, and the temperature difference between the bottom and top of the battery pack tends to be constant, and the second power limit obtained by the transition is 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.

[0064] In this embodiment, based on the different current states of the battery pack, as well as the first time period corresponding to the maximum temperature difference between the top and bottom of the battery pack and the second time period corresponding to the minimum temperature difference between the top and bottom of the battery pack, the purpose of more accurately determining the low-temperature power limit of the battery pack from the three-dimensional perspective of the entire pack is achieved. This can overcome the defect of the existing method of only being able to determine the power limit of the battery pack in a two-dimensional plane, so that the target power limit corresponding to the different current states of the battery pack can be determined more reliably and stably based on the precise low-temperature power limit.

[0065] In another embodiment, if Figure 6As shown, before step S101, that is, before obtaining the current state and measured data of the battery pack, the battery control method further includes: S601: Testing the battery pack to obtain a top test temperature and a bottom test temperature of the battery pack; S602: Based on the top test temperature and the bottom test temperature, determine the maximum test temperature difference after the battery pack enters the cooling state and the first time duration corresponding to the maximum test temperature difference, and determine the minimum test temperature difference after the battery pack exits the cooling state and the second time duration corresponding to the minimum test temperature difference; S603: Determine the maximum test temperature difference as the preset temperature difference, and store the preset temperature difference, the first time duration, and the second time duration.

[0066] 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.

[0067] As an example, in step S601, when the on-board controller tests the battery pack in the whole vehicle, the top temperature data corresponding to each moment is obtained through sensors at different positions on the top of the battery cell in the battery pack, and the bottom temperature data corresponding to each moment is obtained through sensors installed at different positions on the bottom of the battery cell in the battery pack. Understandably, due to the limitation of process assembly, in the working state of the vehicle, only the temperature sensor is installed on the top of the battery cell of the battery pack, and the sensor cannot be installed on the bottom of the battery cell. Therefore, when testing the battery pack, a sensor is temporarily installed on the bottom of the battery cell of the battery pack to obtain test data including a preset temperature difference, a first duration, and a second duration. In this example, under the test condition of the battery pack, a sensor is installed on the top of the battery cell of the battery pack to collect the top test temperature of the battery pack, and a sensor is temporarily installed on the bottom of the battery cell of the battery pack to collect the bottom test temperature of the battery pack. The position where the sensor is arranged on the top of the battery cell corresponds to a top test temperature at each moment. The position where the sensor is temporarily installed on the bottom of the battery cell corresponds to a bottom test temperature at each moment.

[0068] The maximum test temperature difference refers to the maximum value of the temperature difference between the top and bottom of the battery pack when the battery pack is tested. The minimum test temperature difference refers to the minimum value of the temperature difference between the top and bottom of the battery pack when the battery pack is tested.

[0069] As an example, in step S602, after the on-board controller determines that the current state of the battery pack during the test is entering the cooling state, the on-board controller calculates the difference between each top test temperature and each bottom test temperature corresponding to each battery cell until the maximum difference is obtained, and determines the maximum difference as the maximum test temperature difference after the battery pack enters the cooling state, and determines the time from the moment the battery pack enters the cooling state to the moment the maximum difference is generated as the first time corresponding to the maximum test temperature difference. After the on-board controller determines that the current state of the battery pack during the test is exiting the cooling state, the on-board controller calculates the difference between each top test temperature and each bottom test temperature corresponding to each battery cell until the minimum difference is obtained, and determines the minimum difference as the minimum test temperature difference after the battery pack exits the cooling state, and determines the time from the moment the battery pack exits the cooling state to the moment the minimum difference is generated as the second time corresponding to the minimum test temperature difference. Understandably, after the battery pack enters the cooling state, since the cold plate is laid flat on the bottom of the battery cell in the battery pack, the temperature drop rate at the bottom of the battery cell is higher than the temperature drop rate at the top of the battery cell. Therefore, the difference between the top test temperature and the bottom test temperature gradually increases until the maximum difference is reached. The difference between the top test temperature and the bottom test temperature is stabilized within the controllable range corresponding to the maximum difference. Therefore, the maximum difference is determined as the maximum test temperature difference after the battery pack enters the cooling state. After the battery pack exits the cooling state, since the cold plate at the bottom of the battery cell stops cooling, the temperature drop rate at the bottom of the battery cell gradually decreases. The difference between the top test temperature and the bottom test temperature gradually decreases until the minimum difference is reached. The difference between the top test temperature and the bottom test temperature is stabilized within the controllable range corresponding to the minimum difference. Therefore, the minimum difference is determined as the minimum test temperature difference after the battery pack enters the cooling state. During the first time period and the second time period, the difference between the top test temperature and the bottom test temperature of the battery pack is constantly changing. The changing difference needs to correspond to different target power limits to ensure the performance of the battery pack. Therefore, it is necessary to determine the first time period and the second time period to more accurately determine the target power limit of the battery pack corresponding to the changing difference. In this example, based on the top test temperature and the bottom test temperature corresponding to each cell in the battery pack, the maximum test temperature difference of the battery pack after entering the cooling state and the minimum test temperature difference after exiting the cooling state can be more accurately determined.

[0070] As an example, in step S603, the on-board controller determines the maximum test temperature difference as the preset temperature difference, and stores the preset temperature difference, the first time duration and the second time duration in the system database, so as to more accurately determine the target power limit of the battery pack under different current states from the three-dimensional perspective of the entire pack based on the preset temperature difference, the first time duration and the second time duration.

[0071] In this embodiment, based on the top test temperature and the bottom test temperature of the battery cell obtained by testing the battery pack, the maximum test temperature difference and the first duration between the top and the bottom of the battery pack after the battery pack enters a cooling state, and the minimum test temperature difference and the second duration between the top and the bottom of the battery pack after the battery pack exits the cooling state 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 duration and the second duration of the battery pack from the three-dimensional perspective of the entire pack, and overcome the defect of the existing temperature difference that can only be determined in a two-dimensional plane, so as to more accurately determine the target power limit of the battery pack from the three-dimensional perspective of the entire pack according to the first duration and the second duration of the battery pack.

[0072] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0073] In one embodiment, a vehicle-mounted controller is provided, such as Figure 7 As shown, it includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the battery control method in the above embodiment is implemented, for example Figure 1 S101-S104 as shown, or Figures 2 to 6 To avoid repetition, it will not be described here.

[0074] In one embodiment, a battery control system is provided, including a sensor, a battery pack and the above-mentioned 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.

[0075] In this embodiment, the on-board controller is connected to the battery pack and is used to obtain the current state of the battery pack in real time. The sensors are respectively connected to the battery pack and the on-board controller for collecting measured data of the battery pack in the current state, and transmitting the collected measured data in the current state to the on-board controller, so that the on-board controller can more accurately determine the low-temperature power limit and high-temperature power limit of the battery pack according to the measured data of the battery pack in the current state, determine the smaller value of the low-temperature power limit and the high-temperature power limit as the target power limit of the battery pack in the current state, and control the battery pack to operate based on the target power limit of the battery pack in the current state, which can effectively improve the working performance and safety performance of the battery pack and has high application value.

[0076] In one embodiment, a car is provided, comprising the battery control system in the above embodiment.

[0077] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0078] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A battery control method, characterized in that: include: Acquire the current state of the battery pack and measured data corresponding to the current state; 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; Determine the smaller value of the low temperature power limit and the high temperature power limit as the target power limit of the battery pack; Based on the target power limit, the battery pack is controlled to operate.

2. The battery control method according to claim 1, characterized in that: The measured data include the lowest top temperature and the highest top temperature; The determining, based on the current state and the measured data, a low temperature power limit value and a high temperature power limit value of the battery pack includes: Determining a low temperature power limit of the battery pack based on a current state of the battery pack, a minimum top temperature, and a preset temperature difference; A high temperature power limit of the battery pack is determined based on a maximum top temperature of the battery pack.

3. The battery control method according to claim 2, characterized in that: The measured data also includes the measured remaining power; The determining, based on the current state and the measured data, a low temperature power limit value and a high temperature power limit value of the battery pack further includes: Determining a 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 a preset temperature difference; A high temperature power limit of the battery pack is determined based on the maximum top temperature of the battery pack and the measured remaining power.

4. The battery control method according to claim 3, characterized in that: The 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: Determining a first power limit value based on the lowest top temperature of the battery pack and the measured remaining power; determining a second power limit value of the battery pack based on the lowest top temperature of the battery pack, the measured remaining power, and a preset temperature difference; A low temperature power limit of the battery pack is determined based on a current state of the battery pack, the first power limit, and the second power limit.

5. The battery control method according to claim 4, characterized in that: The determining the second power limit value of the battery pack based on the lowest top temperature of the battery pack, the measured remaining power and the preset temperature difference includes: Determining a minimum bottom temperature of the battery pack based on the minimum top temperature and the preset temperature difference; A second power limit value of the battery pack is determined based on the lowest bottom temperature of the battery pack and the measured remaining power.

6. The battery control method according to claim 4, characterized in that: The 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 includes: If the current state is not in the cooling state, determining the low temperature power limit value of the battery pack to be the first power limit value; If the duration of the current state entering the cooling state is less than the first duration, determining that the low temperature power limit of the battery pack is transitioned from the first power limit to the second power limit; If the duration of the current state entering the cooling state is greater than or equal to the first duration, determining the low temperature power limit value of the battery pack to be the second power limit value; If the duration of the current state exiting the cooling state is less than a second duration, determining that the low temperature power limit of the battery pack transitions from the second power limit to the first power limit; If the duration of the current state exiting the cooling state is greater than or equal to the second duration, the low temperature power limit value of the battery pack is determined to be the first power limit value.

7. The battery control method according to claim 6, characterized in that: Before obtaining the current state and measured data of the battery pack, the battery control method further includes: Testing a battery pack to obtain a top test temperature and a bottom test temperature of the battery pack; Based on the top test temperature and the bottom test temperature, determine a maximum test temperature difference after the battery pack enters a cooling state and a first duration corresponding to the maximum test temperature difference, and determine a minimum test temperature difference after the battery pack exits a cooling state and a second duration corresponding to the minimum test temperature difference; The maximum test temperature difference is determined as the preset temperature difference, and the preset temperature difference, the first time length, and the second time length are stored.

8. A vehicle-mounted controller, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the battery control method according to any one of claims 1 to 7 is implemented.

9. A battery control system, characterized in that: It comprises a sensor, a battery pack and the vehicle-mounted controller as claimed in claim 8, 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.

10. An automobile, characterized in that: Includes the battery control system as described in claim 9.

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