Battery temperature control method and system based on new energy automobile

Abstract

The invention relates to the technical field of battery temperature control, and particularly discloses a battery temperature control method and system based on a new energy automobile, and the method comprises the following steps: S1, determining different working conditions based on a preset power node and a preset duration node; constructing a three-dimensional space model of the battery, determining a reference point acquisition point, and determining a contour line of the temperature when the battery operates under different working conditions; s2, determining projection points, and connecting the projection points on the surface of the three-dimensional space model to obtain projection lines; grouping the projection lines, determining representative lines, and sorting the representative lines to obtain a first sequence; determining a target sorting position in the first sorting, and determining a target line in the representative lines; and S3, determining a target range according to the representative line, and controlling the average temperature in the target range to be within the temperature range. According to the invention, the problem of local overheating / supercooling in the working process of the battery can be avoided, and the safety of the new energy automobile is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery temperature control, and in particular to a battery temperature control method and system based on new energy vehicles. Background Art

[0002] With the continuous advancement of science and technology and the increasing awareness of environmental protection, the new energy vehicle industry has ushered in unprecedented development opportunities. As one of the core components of new energy vehicles, the performance of batteries directly affects the safety of new energy vehicles.

[0003] Batteries generate heat due to charging and discharging during operation, and the performance, life and safety of the battery are closely related to its operating temperature. Excessively high temperatures will accelerate battery performance degradation and increase the risk of thermal runaway; excessively low temperatures will reduce the battery's available capacity and discharge capacity, affecting the vehicle's endurance and charging efficiency.

[0004] Conventional battery temperature control methods, such as liquid cooling control, intelligently adjust the temperature through the coolant flow rate control system (pump speed and valve) according to the battery temperature changes. When the battery temperature is too high, the coolant flow rate is increased; when the temperature is close to the normal range, the pump speed is reduced to save energy, thereby ensuring that the battery temperature is within an appropriate range. However, in actual use, the temperature of different parts of the battery may also be different. In this case, increasing the coolant flow rate may cause the battery temperature at a certain position to be too low, or reducing the coolant flow rate may cause the battery temperature at a certain position to be too high. Summary of the invention

[0005] The purpose of the present invention is to provide a battery temperature control method and system based on new energy vehicles to solve the following technical problems: The temperature of different parts of the battery may be different. In this case, increasing the coolant flow rate may cause the battery temperature at a certain position to be too low, or reducing the coolant flow rate may cause the battery temperature at a certain position to be too high.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A battery temperature control method based on a new energy vehicle comprises the following steps: S1: Set a number of power nodes and duration nodes in the preset output power interval and battery single working time interval, and determine N different working conditions. Different working conditions correspond to different power nodes and / or duration nodes. The target number , n1 and n2 represent the total number of power nodes and duration nodes respectively; Constructing a three-dimensional space model of the battery, setting a plurality of collection points at preset distance intervals in the three-dimensional space model, obtaining the temperature at the collection points after the battery is operated in the ath working condition, and drawing temperature contour lines; S2: Determine the projection point of any point on the contour line on the reference surface, the reference surface being the surface in the three-dimensional space model that is closest to the point on the contour line, and connect the projection points on the surface of the three-dimensional space model to obtain a projection line; The projection lines are grouped, and the similarity between any two projection lines in the group is greater than a preset similarity threshold value P, a preset screening step is performed to determine a representative line in the group, and the representative lines are sorted in descending order according to the size of the judgment quantity to obtain a first sort, where the judgment quantity represents the total number of projection lines in the group corresponding to the representative line; Determine a target sorting position m in the first sorting, wherein the target sorting position m satisfies the constraint: and , represents the total length of the first m representative lines in the first sorting, Lys represents a preset total length threshold, and the representative lines at the first m sorting positions in the first sorting are taken as target lines; S3: With point A on the target line as the center, draw a circle with a radius of a preset value R, and use it as the target circle. The target circle is within the target surface, and the target surface is the plane where point A is located in the three-dimensional space model. The target circles are merged to obtain the target range; A cooling pipe is installed on the battery surface along the target line, the average temperature within the target range is obtained in real time, and the flow rate of the coolant in the cooling pipe is controlled based on the PID control algorithm to ensure that the average temperature within the target range is within a preset temperature range.

[0007] As a further solution of the present invention: in the step S2, when the total length of all representative curves in the first sorting is less than the total length threshold, the following steps are performed: Step 1: Set the similarity threshold , and regroup the projection lines, and determine again the total length of all representative curves in the first sorting, Indicates the preset similarity threshold adjustment value; When the total length of all representative curves in the new first sorting is less than the total length threshold, repeat the above steps; Step 2: When the similarity threshold P≥Pmax, if the total length of all representative curves in the corresponding first sorting is still less than the total length threshold, repeat steps S1-S2 to obtain projection lines again, and group the projection lines again, and repeat step 1, where Pmax represents the preset maximum similarity value, until the total length of all representative curves in the first sorting is greater than or equal to the total length threshold.

[0008] As a further solution of the present invention: in the step S3, when the flow rate of the coolant reaches the maximum flow rate, the average temperature within the target range is still rising, and an early warning message is sent for prompting.

[0009] As a further solution of the present invention: in step S2, the process of determining the similarity of the projection lines specifically includes: A coordinate system is established with the preset position as the origin, the functional relationship of the projection line is determined, and the similarity of the projection line is determined based on the Fréchet distance.

[0010] As a further solution of the present invention: in the step S2, in the process of obtaining the first sorting, when two or more judgment numbers are the same, the representative lines corresponding to the group with a larger total length of projection lines are ranked higher.

[0011] As a further solution of the present invention: in the step S2, when the distances between the point c on the contour line C and two or more planes in the three-dimensional space model are the same and are the minimum, the following steps are performed: The plane with the same minimum distance from the three-dimensional space model to point c is taken as the undetermined plane, the proportion of the projection point corresponding to the contour line C in the undetermined plane is determined, and the undetermined plane corresponding to the maximum proportion is taken as the reference plane of point c.

[0012] As a further solution of the present invention: in the step S3, when the point A is on the intersection line B of two planes in the three-dimensional space model, a line segment with a length of R and a midpoint A is determined on the intersection line B, and it is used as the target circle corresponding to point A.

[0013] As a further solution of the present invention: in the step S2, the process of determining the representative line specifically includes: The projection line in the group is taken as the pending line, the pending line X is taken as the reference line, the total similarity PZ between the reference line and the pending line is determined, and the pending line corresponding to the maximum total similarity is taken as the representative line.

[0014] A battery temperature control system based on new energy vehicles, comprising: Acquisition module: Set several power nodes and duration nodes in the preset output power interval and battery single working time interval, determine N different working conditions, and the power nodes and / or duration nodes corresponding to different working conditions are different. The target number , n1 and n2 represent the total number of power nodes and duration nodes respectively; Constructing a three-dimensional space model of the battery, setting a plurality of collection points at preset distance intervals in the three-dimensional space model, obtaining the temperature at the collection points after the battery is operated in the ath working condition, and drawing temperature contour lines; Analysis module: determining the projection point of any point on the contour line on the reference surface, the reference surface being the surface in the three-dimensional space model that is closest to the point on the contour line, connecting the projection points on the surface of the three-dimensional space model to obtain a projection line; The projection lines are grouped, and the similarity between any two projection lines in the group is greater than a preset similarity threshold value P, a preset screening step is performed to determine a representative line in the group, and the representative lines are sorted in descending order according to the size of the judgment quantity to obtain a first sort, where the judgment quantity represents the total number of projection lines in the group corresponding to the representative line; Determine a target sorting position m in the first sorting, wherein the target sorting position m satisfies the constraint: and , represents the total length of the first m representative lines in the first sorting, Lys represents a preset total length threshold, and the representative lines at the first m sorting positions in the first sorting are taken as target lines; Control module: With point A on the target line as the center, a circle with a radius of a preset value R is drawn as the target circle, the target circle is within the target surface, and the target surface is the plane where point A is located in the three-dimensional space model, and the target circles are merged to obtain the target range; A cooling pipe is installed on the battery surface along the target line, the average temperature within the target range is obtained in real time, and the flow rate of the coolant in the cooling pipe is controlled based on the PID control algorithm to ensure that the average temperature within the target range is within a preset temperature range.

[0015] Beneficial effects of the present invention: In this solution, by selecting a number of power nodes and duration nodes at certain intervals within a preset output power range and working duration range, a plurality of different working conditions are constructed, and these working conditions cover a variety of working conditions that the battery may encounter during actual use, so that the temperature distribution characteristics of the battery can be comprehensively observed through multiple sets of data in the simulation stage to ensure that the results are not limited to a single working condition. By constructing a three-dimensional model of the battery and setting acquisition points therein to obtain temperature information, temperature contours can be obtained, so that the spatial distribution of temperature in different regions can be better understood, providing basic data and data for subsequent analysis. Reference, so that the control strategy can be formulated based on more sufficient and more realistic working condition data, improving the adaptability of the solution to actual usage scenarios; then, the projection of any point on the contour line on the reference surface is connected to obtain the projection line; it is worth noting that the reference surface is closest to the internal high-temperature area in space, and the corresponding projection line also represents the shortest heat transfer path from the internal hot spot to the external surface. Laying cooling pipes on the outside with the projection line as a guide can effectively improve the pertinence and efficiency of cooling measures, allowing the cooling medium to act on the outside of the area that needs cooling most, thereby quickly taking away the excessive internal heat on the shortest heat transfer path; then Then, representative lines are selected by grouping and similarity determination, and the target lines are sorted and determined according to the length characteristics of these representative lines, so that representative lines are selected from many possible temperature characteristic curves, so that all complex curves do not need to be processed comprehensively, but the control strategy is designed focusing on the most representative and influential curves. This screening and representative extraction process helps to determine a more reasonable cooling pipe layout direction and area, thereby achieving higher accuracy and efficiency in the execution of the control strategy; finally, a circle with a certain radius is made with a specific point on the target line as the center, and the target range is obtained by merging, so that the specific key area on the battery surface can be precisely cooled. The cooling pipe is installed near the target line, and the coolant flow rate is dynamically adjusted by the PID control algorithm to ensure that the average temperature within the target range is maintained within the preset ideal temperature range. The advantage of this point-to-surface local precise control method is that with the help of the accurate target area and representative characteristic lines provided by the previous two steps, differentiated cooling deployment can be achieved, making the cooling measures more targeted. When the target area is approximately isothermal and reasonably delineated, the PID control will be more sensitive and efficient in adjusting the fluid flow rate, thereby reducing the possibility of local deviations. The present invention can maintain the temperature field as evenly as possible within a reasonable range during the actual operation of the battery, effectively reduce the probability of local overheating or overcooling of the battery during operation, and improve the safety and performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] Figure 1 It is a flow chart of a battery temperature control method based on new energy vehicles 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 only 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] See also Figure 1 As shown, the present invention is a battery temperature control method based on a new energy vehicle, comprising the following steps: S1: Set a number of power nodes and duration nodes in the preset output power interval and battery single working time interval, and determine N different working conditions. Different working conditions correspond to different power nodes and / or duration nodes. The target number , n1 and n2 represent the total number of power nodes and duration nodes respectively; Constructing a three-dimensional space model of the battery, setting a plurality of collection points at preset distance intervals in the three-dimensional space model, obtaining the temperature at the collection points after the battery is operated in the ath working condition, and drawing temperature contour lines; S2: Determine the projection point of any point on the contour line on the reference surface, the reference surface being the surface in the three-dimensional space model that is closest to the point on the contour line, and connect the projection points on the surface of the three-dimensional space model to obtain a projection line; The projection lines are grouped, and the similarity between any two projection lines in the group is greater than a preset similarity threshold value P, a preset screening step is performed to determine a representative line in the group, and the representative lines are sorted in descending order according to the size of the judgment quantity to obtain a first sort, where the judgment quantity represents the total number of projection lines in the group corresponding to the representative line; Determine a target sorting position m in the first sorting, wherein the target sorting position m satisfies the constraint: and , represents the total length of the first m representative lines in the first sorting, Lys represents a preset total length threshold, and the representative lines at the first m sorting positions in the first sorting are taken as target lines; S3: With point A on the target line as the center, draw a circle with a radius of a preset value R, and use it as the target circle. The target circle is within the target surface, and the target surface is the plane where point A is located in the three-dimensional space model. The target circles are merged to obtain the target range; A cooling pipe is installed on the battery surface along the target line, the average temperature within the target range is obtained in real time, and the flow rate of the coolant in the cooling pipe is controlled based on the PID control algorithm to ensure that the average temperature within the target range is within a preset temperature range.

[0020] It should be noted that by selecting several power nodes and duration nodes at certain intervals within the preset output power range and working time range, a number of different working conditions are constructed. These working conditions cover a variety of working conditions that the battery may encounter during actual use. In the simulation stage, multiple sets of data are used to comprehensively observe the temperature distribution characteristics of the battery to ensure that the results are not limited to a single working condition. By constructing a three-dimensional model of the battery and setting collection points in it to obtain temperature information, temperature contours are obtained, which can better understand the spatial distribution of temperature in different areas, provide basic data and reference for subsequent analysis, and make the control The control strategy can be formulated based on more sufficient and more realistic working condition data, improving the adaptability of the solution to actual usage scenarios; then, the projection of any point on the contour line on the reference surface is connected to obtain the projection line; it is worth noting that the reference surface is closest to the internal high-temperature area in space, and the corresponding projection line represents the shortest heat transfer path from the internal hot spot to the external surface. Laying cooling pipes on the outside with the projection line as a guide can effectively improve the pertinence and efficiency of cooling measures, allowing the cooling medium to act on the outside of the area that needs cooling the most, thereby quickly taking away the excessive internal heat on the shortest heat transfer path; then, through Representative lines are selected by grouping and similarity judgment, and the target lines are sorted and determined according to the length characteristics of these representative lines, so that representative lines are selected from many possible temperature characteristic curves, so that all complex curves do not need to be processed comprehensively, but the control strategy is designed focusing on the most representative and influential curves. This screening and representative extraction process helps to determine a more reasonable cooling pipe layout direction and area, thereby achieving higher accuracy and efficiency in the execution of the control strategy; finally, a circle with a certain radius is made with a specific point on the target line as the center, and the target range is obtained by merging, so that the specific key area on the battery surface can be precisely cooled. The cooling pipe is installed near the target line, and the coolant flow rate is dynamically adjusted by the PID control algorithm to ensure that the average temperature within the target range is maintained within the preset ideal temperature range. The advantage of this point-to-surface local precise control method is that with the help of the accurate target area and representative characteristic lines provided by the previous two steps, differentiated cooling deployment can be achieved, making the cooling measures more targeted. When the target area is approximately isothermal and reasonably delineated, the PID control will be more sensitive and efficient in adjusting the fluid flow rate, thereby reducing the possibility of local deviations.

[0021] In another preferred embodiment of the present invention, in step S2, when the total length of all representative curves in the first sorting is less than the total length threshold, the following steps are performed: Step 1: Set the similarity threshold , and regroup the projection lines, and determine again the total length of all representative curves in the first sorting, Indicates the preset similarity threshold adjustment value; When the total length of all representative curves in the new first sorting is less than the total length threshold, repeat the above steps; Step 2: When the similarity threshold P≥Pmax, if the total length of all representative curves in the corresponding first sorting is still less than the total length threshold, repeat steps S1-S2 to obtain projection lines again, and group the projection lines again, and repeat step 1, where Pmax represents the preset maximum similarity value, until the total length of all representative curves in the first sorting is greater than or equal to the total length threshold.

[0022] It can be understood that by dynamically adjusting the similarity threshold P and repeating steps S1-S2 when necessary, it is ensured that the finally selected representative curve set (i.e., the representative curves in the first sorting) can meet the preset total length threshold requirement. When the total length of all representative curves obtained under the original similarity threshold is still insufficient to meet the total length threshold, the similarity threshold P will be increased by a preset increment. , so as to classify and group the projection lines more broadly or strictly (depending on the changes in the classification results caused by the increase of P), and then re-determine the total length of all representative curves in the first sorting. Through this iterative method, different similarity grouping standards are constantly tried to obtain more or more suitable representative curves (that is, while ensuring the similarity between curves, the total length of the representative curves can be ensured to reach the target standard). If the total length threshold requirement is still not met after gradually increasing P until Pmax (the preset maximum similarity threshold upper limit), it will return to the previous link and repeat steps S1-S2 to obtain new projection line data, group and select again until the total length threshold is reached. Through such adaptive adjustment and circulation, the method can flexibly optimize the selection process of representative curves under different conditions, ensuring that the final representative curve set has sufficient reference value and robustness for the subsequent determination and execution of cooling strategies.

[0023] In another preferred embodiment of the present invention, in step S3, when the flow rate of the coolant reaches the maximum flow rate and the average temperature within the target range is still rising, an early warning message is sent for prompting.

[0024] In another preferred embodiment of the present invention, in step S2, the process of determining the similarity of the projection lines specifically includes: A coordinate system is established with the preset position as the origin, the functional relationship of the projection line is determined, and the similarity of the projection line is determined based on the Fréchet distance.

[0025] It should be noted that Fréchet distance is a geometric indicator used to measure the similarity between two curves (or paths). Different from the general point-to-point distance measurement, Fréchet distance not only considers the spatial distance relationship between points on the curve, but also considers the order and matching method of the two curves moving along their respective parameter directions.

[0026] In another preferred embodiment of the present invention, in the step S2, in the process of obtaining the first sorting, when two or more judgment numbers are the same, the representative lines corresponding to the group with a larger total length of projection lines are ranked higher.

[0027] In another preferred embodiment of the present invention, in step S2, when the distances between point c on the contour line C and two or more planes in the three-dimensional space model are the same and are minimum, the following steps are performed: The plane with the same distance from the three-dimensional model and point c and with the minimum value is taken as the undetermined plane, the proportion of the projection point corresponding to the contour line C in the undetermined plane is determined, and the undetermined plane corresponding to the maximum proportion is taken as the reference plane of point c In another preferred embodiment of the present invention, in the step S3, when the point A is on the intersection line B of two planes in the three-dimensional space model, a line segment with a length of R and a midpoint A is determined on the intersection line B and is used as the target circle corresponding to the point A.

[0028] In another preferred embodiment of the present invention, in step S2, the process of determining the representative line specifically includes: The projection line in the group is taken as the pending line, the pending line X is taken as the reference line, the total similarity PZ between the reference line and the pending line is determined, and the pending line corresponding to the maximum total similarity is taken as the representative line.

[0029] A battery temperature control system based on new energy vehicles, comprising: Acquisition module: Set several power nodes and duration nodes in the preset output power interval and battery single working time interval, determine N different working conditions, and the power nodes and / or duration nodes corresponding to different working conditions are different. The target number , n1 and n2 represent the total number of power nodes and duration nodes respectively; Constructing a three-dimensional space model of the battery, setting a plurality of collection points at preset distance intervals in the three-dimensional space model, obtaining the temperature at the collection points after the battery is operated in the ath working condition, and drawing temperature contour lines; Analysis module: determining the projection point of any point on the contour line on the reference surface, the reference surface being the surface in the three-dimensional space model that is closest to the point on the contour line, connecting the projection points on the surface of the three-dimensional space model to obtain a projection line; The projection lines are grouped, and the similarity between any two projection lines in the group is greater than a preset similarity threshold value P, a preset screening step is performed to determine a representative line in the group, and the representative lines are sorted in descending order according to the size of the judgment quantity to obtain a first sort, where the judgment quantity represents the total number of projection lines in the group corresponding to the representative line; Determine a target sorting position m in the first sorting, wherein the target sorting position m satisfies the constraint: and , represents the total length of the first m representative lines in the first sorting, Lys represents a preset total length threshold, and the representative lines at the first m sorting positions in the first sorting are taken as target lines; Control module: With point A on the target line as the center, a circle with a radius of a preset value R is drawn as the target circle, the target circle is within the target surface, and the target surface is the plane where point A is located in the three-dimensional space model, and the target circles are merged to obtain the target range; A cooling pipe is installed on the battery surface along the target line, the average temperature within the target range is obtained in real time, and the flow rate of the coolant in the cooling pipe is controlled based on the PID control algorithm to ensure that the average temperature within the target range is within a preset temperature range.

[0030] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A battery temperature control method based on new energy vehicles, characterized in that: The following steps are involved: S1: Set a number of power nodes and duration nodes within the preset output power range and battery single working time range, and determine N different working conditions. Different working conditions correspond to different power nodes and / or duration nodes. The target number , n1 and n2 represent the total number of power nodes and duration nodes respectively; Constructing a three-dimensional spatial model of the battery, setting a plurality of collection points at preset intervals in the three-dimensional spatial model, obtaining the temperature at the collection points after the battery is operated under the a-th operating condition, and drawing temperature contour lines; S2: Determine the projection point of any point on the contour line on a reference surface, where the reference surface is the surface in the three-dimensional space model that is closest to the point on the contour line, and connect the projection points on the surface of the three-dimensional space model to obtain a projection line; The projection lines are grouped, and if the similarity between any two projection lines in the group is greater than a preset similarity threshold P, a preset screening step is performed to determine a representative line in the group, and the representative lines are sorted in descending order according to the number of judgments to obtain a first sort, where the number of judgments represents the total number of projection lines in the group corresponding to the representative line; Determine a target sort position m in the first sort, where the target sort position m satisfies the constraint: and , represents the total length of the first m representative lines in the first sorting, Lys represents a preset total length threshold, and the representative lines at the first m sorting positions in the first sorting are used as target lines; S3: With point A on the target line as the center, draw a circle with a radius of a preset value R, and use it as the target circle. The target circle is within the target surface, and the target surface is the plane where point A is located in the three-dimensional space model. The target circles are merged to obtain the target range; A cooling pipe is installed on the battery surface along the target line, the average temperature within the target range is obtained in real time, and the flow rate of the coolant in the cooling pipe is controlled based on the PID control algorithm to ensure that the average temperature within the target range is within the preset temperature range.

2. A battery temperature control method based on new energy vehicles according to claim 1, characterized in that: In step S2, when the total length of all representative curves in the first sorting is less than the total length threshold, the following steps are performed: Step 1: Let the similarity threshold , and regroup the projection lines, and determine again the total length of all representative curves in the first sorting, Indicates the preset similarity threshold adjustment value; When the total length of all representative curves in the new first sorting is less than the total length threshold, repeat the above steps; Step 2: When the similarity threshold P ≥ Pmax, if the total length of all representative curves in the corresponding first sort is still less than the total length threshold, repeat steps S1-S2 to obtain projection lines again, group the projection lines again, and repeat step 1, where Pmax represents the preset maximum similarity value, until the total length of all representative curves in the first sort is greater than or equal to the total length threshold.

3. The battery temperature control method based on new energy vehicles according to claim 1, characterized in that: In step S3, when the flow rate of the coolant reaches the maximum flow rate and the average temperature within the target range is still rising, an early warning message is sent to prompt.

4. The battery temperature control method based on new energy vehicles according to claim 1, characterized in that: In step S2, the process of determining the similarity of the projection lines specifically includes: A coordinate system is established with the preset position as the origin, a functional relationship of the projection lines is determined, and the similarity of the projection lines is determined based on the Fréchet distance.

5. The battery temperature control method based on new energy vehicles according to claim 1, characterized in that: In the step S2, during the process of obtaining the first ranking, when two or more judgment numbers are the same, the representative line corresponding to the group with a larger total length of projection lines is ranked higher.

6. A battery temperature control method based on new energy vehicles according to claim 1, characterized in that: In step S2, when the distances between point c on the contour line C and two or more planes in the three-dimensional space model are the same and are minimum, the following steps are performed: The plane with the same minimum distance from the three-dimensional space model to point c is used as the undetermined plane, the proportion of the projection point corresponding to the contour line C in the undetermined plane is determined, and the undetermined plane corresponding to the maximum proportion is used as the reference plane of point c.

7. The battery temperature control method based on new energy vehicles according to claim 1, characterized in that: In step S3, when the point A is on the intersection line B of two planes in the three-dimensional space model, a line segment with a length of R and a midpoint of A is determined on the intersection line B, and it is used as the target circle corresponding to point A.

8. The battery temperature control method based on new energy vehicles according to claim 1, characterized in that: In step S2, the process of determining the representative line specifically includes: The projection lines in the group are taken as the pending lines, the pending line X is taken as the reference line, the total similarity PZ between the reference line and the pending line is determined, and the pending line corresponding to the maximum total similarity is taken as the representative line.

9. A battery temperature control system based on new energy vehicles, characterized in that: include: Acquisition module: Set several power nodes and duration nodes in the preset output power interval and battery single working time interval, determine N different working conditions, and the power nodes and / or duration nodes corresponding to different working conditions are different. The target number , n1 and n2 represent the total number of power nodes and duration nodes respectively; Constructing a three-dimensional spatial model of the battery, setting a plurality of collection points at preset intervals in the three-dimensional spatial model, obtaining the temperature at the collection points after the battery is operated under the a-th operating condition, and drawing temperature contour lines; Analysis module: determining the projection point of any point on the contour line on the reference surface, where the reference surface is the surface in the three-dimensional space model that is closest to the point on the contour line, and connecting the projection points on the surface of the three-dimensional space model to obtain a projection line; The projection lines are grouped, and if the similarity between any two projection lines in the group is greater than a preset similarity threshold P, a preset screening step is performed to determine a representative line in the group, and the representative lines are sorted in descending order according to the number of judgments to obtain a first sort, where the number of judgments represents the total number of projection lines in the group corresponding to the representative line; Determine a target sort position m in the first sort, where the target sort position m satisfies the constraint: and , represents the total length of the first m representative lines in the first sorting, Lys represents a preset total length threshold, and the representative lines at the first m sorting positions in the first sorting are used as target lines; Control module: With point A on the target line as the center, draw a circle with a radius of a preset value R, and use it as the target circle. The target circle is within the target surface, and the target surface is the plane where point A is located in the three-dimensional space model. The target circles are merged to obtain the target range; A cooling pipe is installed on the battery surface along the target line, the average temperature within the target range is obtained in real time, and the flow rate of the coolant in the cooling pipe is controlled based on the PID control algorithm to ensure that the average temperature within the target range is within the preset temperature range.

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