A battery thermal management control method based on charging rate

Abstract

The present invention discloses a battery thermal management control method based on charging rate, comprising: recording the charging current data of the battery within a time period of △t, calculating and updating the process root mean square current rate value ROC; obtaining the charging cooling strategy under the current ROC through the life simulation result confirmation table; judging the real-time obtained maximum battery temperature T according to the step charging cooling strategy Bmax and battery water inlet temperature T Win Whether the cooling system start-up conditions are met, if yes, the cooling system is turned on, otherwise the cooling system is turned off; after charging is completed, ROC update is stopped, the cooling system is turned off, and charging is ended. The present invention dynamically adjusts the start and stop conditions of the cooling system by monitoring parameters such as battery temperature and current to avoid excessively high or low battery temperature, thereby improving charging efficiency and battery life, thereby achieving the purpose of reducing energy consumption, and at the same time saving charging time.

Description

Technical Field

[0001] The present invention relates to the technical field of battery thermal management, and more specifically to a battery thermal management control method based on charging rate. Background Art

[0002] With the popularity of electric vehicles, battery technology has become one of the core technologies of electric vehicles. Battery performance directly affects the range, charging time and service life of electric vehicles, and battery thermal management is one of the important means to ensure battery performance and safety. The main purpose of battery thermal management is to ensure that the battery operates within the optimal temperature range to avoid the impact of overheating or overcooling on battery performance and life.

[0003] Existing battery thermal management technologies mainly use coolant circulation and fan heat dissipation. Coolant circulation is to flow the coolant inside the battery to take away the heat generated by the battery, and then dissipate the heat through the radiator. Fan heat dissipation is to take away the heat inside the battery through the fan and then discharge it into the outside air. In addition, some technologies use new materials such as phase change materials and thermoelectric materials to improve the thermal management effect of the battery. Although existing battery thermal management technologies can effectively reduce the operating temperature of the battery, these technologies still have some problems in practical applications.

[0004] First, most of the existing battery thermal management technologies use fixed parameter control and cannot be adjusted according to the actual working state of the battery, resulting in excessive or insufficient cooling of the battery, which not only wastes energy but also affects the performance and life of the battery. Second, during the charging process, the existing battery thermal management technology often ignores the impact of the charging rate on the temperature rise of the battery, resulting in the occupation of charging power, thus affecting the charging time. Third, the existing battery thermal management technology does not consider the state of the battery after switching from charging mode to driving mode, and often cannot adjust the cooling strategy in time, resulting in excessive battery temperature. The battery needs to be cooled immediately during driving, which affects the performance and range of the battery. Summary of the invention

[0005] The present invention provides a battery thermal management control method based on charging rate, aiming to solve the above problems existing in the existing battery thermal management technology.

[0006] The present invention adopts the following technical solution: A battery thermal management control method based on charging rate includes the following steps: S1. Continuously record the battery charging current data within the time period of △t, calculate the process root mean square current multiple value ROC and update it; S2. Obtain the charging cooling strategy under the current ROC through the life simulation result confirmation table; S3. According to the charging and cooling strategy in step S2, determine the maximum battery temperature T obtained in real time Bmax and the battery water inlet temperature T Win Whether the cooling system start-up conditions are met, if yes, the cooling system is turned on, otherwise, the cooling system is turned off; S4. After charging is completed, ROC update is stopped, the cooling system is shut down, and charging is ended.

[0007] In a preferred embodiment, the calculation formula of ROC in the above step S1 is as follows: , where I chg (i) refers to the charging current data at the i-th moment within △t; C0 and SOH are the battery rated capacity and battery health obtained at the beginning of charging, respectively.

[0008] In a preferred embodiment, the continuous recording of the battery charging current data within a period of Δt in the above step S1 is started after the battery starts to work for a period of t0 when charging begins.

[0009] In a preferred embodiment, the ROC needs to set an initial value ROC0.

[0010] In a preferred embodiment, in the above step S2, when the current ROC=ROC1, the maximum opening temperature of the cooling system is T max1 , the target water temperature is T tar1 ; Current ROC = ROC k When the cooling system opens, the maximum temperature is T maxk , the target water temperature is T tark , k is an integer greater than 1.

[0011] In a preferred embodiment, in the above step S3, if the maximum battery temperature T Bmax When the driving mode cooling system activation conditions are exceeded, the driving mode cooling strategy is adjusted to directly start the cooling system to use the energy of the charging pile to cool the battery.

[0012] Furthermore, the above step S3 also includes a cooling system start-stop protection mechanism, that is, during the cooling process, after the cooling unit has worked continuously for t1 time, the ROC is re-judged, and the start-stop conditions of the cooling system are obtained with the new ROC; during this period, if the conditions for exiting the cooling mode are met, the ROC is directly re-judged to prevent the cooling unit from repeatedly entering the cooling mode.

[0013] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following advantages: 1. The present invention obtains the charging cooling strategy under the current ROC by calculating the process root mean square current rate value ROC and confirming the table according to the life simulation result. During the charging process, by monitoring the temperature and current and other parameters of the battery, the opening and closing conditions of the cooling system are dynamically adjusted to avoid the battery temperature being too high or too low, thereby improving the charging efficiency and battery life, thereby achieving the purpose of reducing energy consumption, and at the same time saving charging time.

[0014] 2. During the charging process, the present invention monitors the maximum temperature of the battery in real time. When the maximum temperature of the battery exceeds the driving refrigeration temperature threshold, the refrigeration is directly started and adjusted to the refrigeration strategy under the driving mode, so as to use the energy of the charging pile to cool the battery, avoiding starting the refrigeration after driving, which affects both the battery life and the endurance.

[0015] 3. In the battery cooling process of the present invention, the cooling unit of the cooling system works for a certain period of time, and then re-determines the charging rate, and performs cooling with the start and stop conditions obtained with the new rate, so as to avoid frequent start and stop of the cooling unit and protect its life. During this period, if the cooling mode is exited, the charging rate is directly re-determined to prevent the cooling unit from repeatedly entering the cooling mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0017] Refer to the following Figure 1 The specific implementation of the present invention is described. In order to fully understand the present invention, many details are described below, but for those skilled in the art, the present invention can be implemented without these details. For well-known components, methods and processes, they are not described in detail below.

[0018] This embodiment provides a battery thermal management control method based on charging rate, which specifically includes the following steps: 1. Plug in the charger to start charging, establish communication with the charger, start charging, obtain the battery rated capacity C0 and battery health SOH value, and obtain the real-time maximum battery temperature T Bmax and the battery water inlet temperature T Win .

[0019] 2. The duration of the charging operation t0, in this embodiment, is specifically set to 30s to filter out the small RMS current value caused by the initial current oscillation.

[0020] 3. Continuously record the charging current data within the duration of △t. In this embodiment, △t is specifically set to 120s, and the data is recorded once per second and written into I chg [△t], calculate the process RMS current multiplier value ROC and update it. The calculation formula of the process RMS current multiplier value ROC is as follows: , where I chg (i) refers to the charging current data at the i-th moment within △t.

[0021] In order to ensure that the battery can perform normal thermal management within the time (t0+Δt) (specifically 150s in this embodiment), an initial value of R0C needs to be set. In this embodiment, the initial value of R0C is 0.2.

[0022] 4. Establish a dynamic battery cooling control model. According to the life simulation result confirmation table, obtain the charging cooling strategy under the current ROC, and then determine T according to the corresponding activation conditions of the strategy. Bmax and T Win Whether the cooling start conditions are met, if so, turn on the cooling, and dynamically adjust the start and stop conditions of the cooling system.

[0023] For example, when the charging rate is 1C, the corresponding maximum opening temperature is 24°C, the target water temperature is 10°C, and the current maximum battery temperature T Bmax =26℃, T Win =20℃, the cooling start condition is met and the cooling should be turned on; when the charging rate is 0.3C, the corresponding maximum temperature is 34℃, the target water temperature is 20℃, and the current maximum battery temperature T Bmax =26℃, T Win =20℃, the cooling start condition is not met and the cooling system is in shutdown state.

[0024] At the same time, by real-time monitoring of the maximum battery temperature T Bmax , when the battery maximum temperature T Bmax If the driving mode cooling start-up conditions are exceeded, the driving mode cooling strategy is adjusted to start cooling directly to use the energy from the charging pile to cool the battery, avoiding the need to turn on cooling due to excessive battery temperature when switching from charging mode to driving mode, which consumes power and affects the vehicle's range. It also affects the battery life (getting energy directly from the charging pile can save the energy loss stored in the battery. If the battery is charged first and then powered from the battery, the battery throughput will be occupied).

[0025] This embodiment also introduces a frequent start-stop protection mechanism for the unit in the above step 4, that is, during the cooling process, after the cooling unit has worked continuously for t1 time (the specific value in this embodiment is 10 minutes), the ROC is re-judged, and the start-stop conditions of the cooling system are obtained by the new ROC to avoid frequent start-stop of the cooling unit; during this period, if the cooling mode exit is satisfied, the ROC is directly re-judged to prevent the cooling unit from repeatedly entering the cooling mode.

[0026] 5. When charging is completed, stop ROC updating, cool the unit and shut down, ending charging.

[0027] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A battery thermal management control method based on charging rate, characterized in that: The following steps are involved: S1. Continuously record the battery charging current data within the time period of △t, calculate the process root mean square current multiple value ROC and update it; S2. Obtain the charging cooling strategy under the current ROC through the life simulation result confirmation table; S3. According to the charging and cooling strategy in step S2, determine the maximum battery temperature T obtained in real time Bmax and battery water inlet temperature T Win Whether the cooling system start-up conditions are met, if yes, the cooling system is turned on, otherwise, the cooling system is turned off; S4. After charging is completed, ROC update is stopped, the cooling system is shut down, and charging is ended.

2. A battery thermal management control method based on charging rate as claimed in claim 1, characterized in that: The calculation formula of ROC in step S1 is as follows: , where I chg (i) refers to the charging current data at the i-th moment within △t; C0 and SOH are the battery rated capacity and battery health obtained at the beginning of charging, respectively.

3. A battery thermal management control method based on charging rate as claimed in claim 1, characterized in that: The step S1 continuously records the charging current data of the battery within a time period of Δt, and starts recording after the charging starts and the battery works for a time period of t0.

4. A battery thermal management control method based on charging rate as claimed in claim 1, characterized in that: The ROC needs to set an initial value ROC0.

5. The battery thermal management control method based on charging rate according to claim 1, characterized in that: In step S2, when the current ROC=ROC1, the maximum opening temperature of the cooling system is T max1 , the target water temperature is T tar1 ; Current ROC = ROC k When the cooling system opens, the maximum temperature is T maxk , the target water temperature is T tark , k is an integer greater than 1.

6. A battery thermal management control method based on charging rate as claimed in claim 1, characterized in that: In step S3, if the maximum battery temperature T Bmax When the driving mode cooling system activation conditions are exceeded, the driving mode cooling strategy is adjusted to directly start the cooling system to use the energy of the charging pile to cool the battery.

7. A battery thermal management control method based on charging rate as claimed in claim 1, characterized in that: The step S3 also includes a cooling system start-stop protection mechanism, that is, during the cooling process, after the cooling unit has worked continuously for t1 time, the ROC is re-judged, and the start-stop conditions of the cooling system are obtained with the new ROC; during this period, if the cooling mode exit condition is met, the ROC is directly re-judged to prevent the cooling unit from repeatedly entering the cooling mode.

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