Battery thermal management method, controller, and mechanical system

Abstract

The application provides a battery thermal management method, a controller and a mechanical system. The battery thermal management method comprises the following steps: collecting the ambient temperature and the internal temperature of each branch of a plurality of branches in parallel with each other and each having a battery pack of a battery system, and determining the external-internal temperature difference of each branch based on the ambient temperature and the internal temperature of each branch; in the case that the external-internal temperature difference of each branch is greater than a temperature difference threshold, performing temperature regulation on each branch so that each branch meets a preset condition, and the preset condition comprises that the external-internal temperature difference of each branch is less than or equal to a preset temperature difference value, and the preset temperature difference value is less than or equal to the temperature difference threshold. In this way, the performance of the battery system comprising the parallel branches can be improved.

Description

Technical Field

[0001] This application relates to the field of battery thermal management technology, and in particular to a battery thermal management method, controller and mechanical system. Background Technology

[0002] With the development of the new energy industry, large-tonnage mechanical systems (such as mining trucks, port machinery, and construction machinery) are rapidly becoming electrified. The power battery systems of these mechanical systems typically consist of multiple parallel branches, each equipped with a battery pack, to provide greater power and meet higher electricity demands. Furthermore, these parallel branches are usually distributed across different locations such as the frame and chassis, at considerable distances, resulting in significant differences in ambient temperature and thermal interference.

[0003] However, in the related technologies, the influence of ambient temperature differences is not effectively considered when thermally managing these parallel branches, which can easily lead to high temperature differences between branches and affect the performance of the battery system.

[0004] The above statements are for the purpose of providing background information in relation to this application only, and do not necessarily constitute prior art. Summary of the Invention

[0005] This application aims to provide a battery thermal management method, controller, and mechanical system to improve the performance of battery systems including parallel branches.

[0006] To achieve the above objectives, the battery thermal management method provided in this application includes:

[0007] The ambient and internal temperatures of each branch in the battery system, which are connected in parallel and each has a battery pack, are collected, and the external and internal temperature differences of each branch are determined based on the ambient and internal temperatures of each branch.

[0008] When the temperature difference between the inside and outside of a branch exceeds a temperature difference threshold, the temperature of the branch is regulated to ensure that the branch meets preset conditions. The preset conditions include that the temperature difference between the inside and outside of the branch is less than or equal to a preset temperature difference value, and the preset temperature difference value is less than or equal to a temperature difference threshold.

[0009] In some embodiments, the ambient temperature and internal temperature of each branch in multiple parallel branches are collected, and the external-internal temperature difference of each branch is determined based on the ambient temperature and internal temperature of each branch, including:

[0010] Collect the internal temperature and ambient temperature of each branch at multiple points, and determine the temperature difference between the inside and outside of each branch based on the average ambient temperature and average internal temperature of each branch.

[0011] The average internal temperature of each branch is the average of the internal temperatures of each branch at multiple points, and the highest internal temperature of each branch is the maximum value of the internal temperatures of each branch at multiple points.

[0012] In some embodiments, before collecting the ambient temperature of each branch at multiple points, the multiple parallel branches are divided into multiple temperature domains according to the different ambient thermal characteristics, so that branches with consistent ambient thermal characteristics are in the same temperature domain. Consistent ambient thermal characteristics include ambient temperatures within the same temperature range. During the process of collecting the ambient temperature of each branch at multiple points, the ambient temperature of each temperature domain at multiple points is collected, and the ambient temperature of each temperature domain at multiple points is used as the ambient temperature of each branch at multiple points within each temperature domain.

[0013] In some embodiments, the preset conditions further include:

[0014] The average internal temperature of the branch is less than or equal to a preset average temperature value, wherein the average internal temperature of the branch is the average of the internal temperatures of the branch at multiple points; and / or,

[0015] The highest internal temperature of a branch is less than or equal to a preset high temperature value, wherein the highest internal temperature of a branch is the maximum value among the internal temperatures of the branch at multiple points.

[0016] In some embodiments, the battery thermal management method further includes at least one of the following:

[0017] When the average internal temperature of a branch exceeds the average temperature threshold, the branch temperature is regulated to make the branch meet the preset conditions. The preset conditions also include that the average internal temperature of the branch is less than or equal to the preset average temperature value, the preset average temperature value is less than or equal to the average temperature threshold, and the average internal temperature of the branch is the average of the internal temperatures of the branch at multiple points.

[0018] If the highest internal temperature of a branch exceeds the high temperature threshold, the branch temperature is regulated to make the branch meet the preset conditions. The preset conditions also include that the highest internal temperature of the branch is less than or equal to the preset high temperature value, the preset high temperature value is less than or equal to the high temperature threshold, and the highest internal temperature of the branch is the maximum value of the internal temperature of the branch among multiple points.

[0019] In some embodiments, temperature regulation of the branch circuit includes:

[0020] Adjust the coolant flow rate in the cooling path used for the cooling branch.

[0021] In some embodiments, adjusting the coolant flow rate in the cooling flow path for the cooling branch includes:

[0022] Adjust the opening of the control valve used to control the flow rate of coolant in the cooling flow path.

[0023] In some embodiments, during the adjustment of the opening of the control valve, the target opening of the control valve is determined based on the temperature difference between the inside and outside of the branch.

[0024] In some embodiments, when determining the target opening degree of the control valve based on the external and internal temperature difference of the branch, the external and internal temperature difference of the branch and a coefficient are used. The product of these factors determines the target opening degree of the control valve.

[0025] In some embodiments, the target opening of the control valve is also determined based on at least one of the average internal temperature of the branch, the highest internal temperature of the branch, and the basic opening of the control valve, wherein the average internal temperature of the branch is the average of the internal temperatures of the branch at multiple points, and the highest internal temperature of the branch is the maximum value of the internal temperatures of the branch at multiple points.

[0026] In some embodiments, when determining the target opening of the control valve based on the average internal temperature of the branch, the target opening of the control valve is determined based on the difference between the average internal temperature of the branch and a target value of the average internal temperature of the branch; and / or, when determining the target opening of the control valve based on the highest internal temperature of the branch, the target opening of the control valve is determined based on the difference between the highest internal temperature of the branch and a target value of the highest internal temperature of the branch.

[0027] In some embodiments, when determining the target opening degree of the control valve based on the difference between the average internal temperature of the branch and a target value of the average internal temperature of the branch, the difference between the average internal temperature of the branch and the target value of the average internal temperature of the branch and a coefficient are used. The product of the two factors determines the target opening degree of the control valve; and / or, when determining the target opening degree of the control valve based on the difference between the highest internal temperature of the branch and the target value of the highest internal temperature of the branch, the difference between the highest internal temperature of the branch and the target value of the highest internal temperature of the branch is used as the factor. The product of these factors determines the target opening degree of the control valve.

[0028] In some embodiments, the difference between the average internal temperature of the branch and the target value of the average internal temperature of the branch and the coefficient are used. The product of, the difference between the highest internal temperature of the branch and the target value of the highest internal temperature of the branch, and the coefficient. The product of the ... The sum of the products determines the target opening degree of the control valve.

[0029] In some embodiments, temperature regulation of the branch is performed for a maximum duration. If time If the branch circuit still fails to meet the preset conditions, then temperature control of the branch circuit will be stopped.

[0030] In some embodiments, It is a constant; or, determined based on at least one of the branch's average internal temperature and highest internal temperature. The average internal temperature of a branch is the average of the internal temperatures of the branch at multiple points, and the highest internal temperature of a branch is the maximum internal temperature of the branch at multiple points.

[0031] In some embodiments, when t is determined based on the average internal temperature of the branch, t is determined based on the difference between the average internal temperature of the branch and the target value of the average internal temperature of the branch; and / or, when t is determined based on the highest internal temperature of the branch, t is determined based on the difference between the highest internal temperature of the branch and the target value of the highest internal temperature of the branch.

[0032] In some embodiments, when determining t based on the difference between the average internal temperature of the branch and a target value of the average internal temperature of the branch, the coefficient is... The product of and determines t; and / or, when determining t based on the difference between the highest internal temperature of the branch and the target value of the highest internal temperature of the branch, the difference between the highest internal temperature of the branch and the target value of the highest internal temperature of the branch and the coefficient. The product of and determines t.

[0033] In some embodiments, it is also based on a base time. ,Sure .

[0034] In some embodiments, the difference between the average internal temperature of the branch and the target value of the average internal temperature of the branch and the coefficient are used. The product of the highest internal temperature of the branch and the difference between the highest internal temperature of the branch and the target value of the highest internal temperature of the branch, and the coefficient. At least one of the products of the base time The sum, determine .

[0035] In some embodiments, if time If the branch still fails to meet the preset conditions, then the temperature control of the branch is stopped, and the current is distributed among the branches to make each branch meet the preset conditions.

[0036] In some embodiments, when distributing current among branches, the current of a branch is determined based on at least one of the branch's average internal temperature and remaining charge; and / or, a PID algorithm is used to distribute current among branches.

[0037] In some embodiments, when determining the current of a branch based on at least one of the average internal temperature of the branch and the remaining charge of the branch, the current of the branch is determined based on at least one of the difference between the average internal temperature of all parallel branches and the average internal temperature of the branch and the difference between the average remaining charge of all branches and the remaining charge of the branch.

[0038] In some embodiments, when determining the branch current based on the difference between the average internal temperature of all branches and the average remaining charge of all branches and the difference between the remaining charge of all branches, the branch current is determined according to the following formula. :

[0039]

[0040] in, It equals the total current divided by the number of branches. The average internal temperature of all branches, The average internal temperature of the branch is The average remaining power of all branches. The remaining power of the branch circuit. , and These are PID parameters.

[0041] In some embodiments, if current distribution among branches still fails to make each branch meet the preset conditions, one of the following methods—current limiting, power-off of abnormal branches, and power-off of the battery system—is used to isolate the abnormal branches.

[0042] In some embodiments, the three methods of current limiting, abnormal branch power-off, and battery system power-off are adopted when the fault level of the abnormal branch is a first-level fault, a second-level fault, and a third-level fault, respectively, with the types of abnormalities corresponding to the first-level fault, the second-level fault, and the third-level fault increasing in that order.

[0043] In addition, the controller provided in this application includes a memory and a processor coupled to the memory, the processor being configured to execute the battery thermal management method of any embodiment based on instructions stored in the memory.

[0044] In addition, the mechanical system provided in this application includes a battery system, which includes multiple parallel branches, each branch including a battery pack with individual cells, and the mechanical system also includes a controller according to any embodiment.

[0045] In some embodiments, the battery system further includes a converter electrically connected between the branch and the load terminal and / or the charging terminal.

[0046] In the process of thermal management of a battery system including parallel branches, this application effectively considers the impact of the difference in ambient temperature between branches, which can reduce the temperature difference amplification effect between parallel branches, improve the consistency between parallel branches, extend the life of each branch in the parallel branches, and improve the performance of the battery system.

[0047] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0048] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0049] Figure 1 This is an electrical architecture diagram of the battery system in an embodiment of this application.

[0050] Figure 2 This is a schematic diagram showing the coordination of the temperature acquisition module, electrical acquisition module, and branch circuit in an embodiment of this application.

[0051] Figure 3 This is a schematic diagram illustrating the division of the temperature domain in an embodiment of this application.

[0052] Figure 4 This is a schematic flowchart of the battery thermal management method in the embodiments of this application.

[0053] Explanation of reference numerals in the attached figures:

[0054] 10. Battery system;

[0055] 1. Branch circuit; 21. Temperature acquisition module; 22. Electrical acquisition module; 3. Converter; 4. Load terminal; 5. Temperature domain; 51. First temperature domain; 52. Second temperature domain; 53. Third temperature domain; 6. Sunlight; 7. Obstruction; 8. Airflow. Detailed Implementation

[0056] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.

[0057] In the description of this application, the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0058] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0059] In the description of this application, "multiple" means at least two, that is, including two, three or more.

[0060] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0061] High-capacity battery systems typically consist of multiple parallel branches. For example, in some mechanical systems, the battery capacity exceeds 1000kWh, and the number of branches reaches more than 20. Due to the structural limitations of mechanical systems, these parallel branches are usually distributed at considerable distances, facing complex operating conditions such as large fluctuations in ambient temperature and strong vibrations and shocks. In this case, the large distance between branches leads to significant differences in environmental thermal interference, easily exacerbating the temperature amplification effect between parallel branches. The temperature amplification effect between parallel branches refers to the vicious cycle of "increased temperature - decreased internal resistance - increased shunt current - increased temperature" that can easily be triggered by local temperature differences between parallel branches, affecting the performance of the battery system. For example, when the temperature of a battery pack on a certain branch rises sharply due to poor ventilation, its internal resistance may decrease by 15% compared to a lower-temperature branch, its shunt current may increase by 20%, and the temperature difference with other branches may increase by more than 10°C within 30 minutes, directly leading to a sharp reduction in the cycle life of that branch.

[0062] It is evident that the multiple parallel branches of the battery system are characterized by large distances between their locations, significant differences in ambient temperature, substantial differences in environmental thermal interference, obvious temperature difference amplification effect, and poor consistency, which poses a significant challenge to battery thermal management.

[0063] In related technologies, the thermal management of these parallel branches does not effectively consider the impact of ambient temperature differences, which can easily lead to high temperature differences between branches, affecting the cycle life of the branches and the performance of the battery system.

[0064] In view of the above, this application provides a battery thermal management method to effectively manage the thermal of a battery system including parallel branches and improve the performance of the battery system including parallel branches.

[0065] Figure 4The battery thermal management method of this application is illustrated by way of example.

[0066] See Figure 4 In this application, the battery thermal management method includes:

[0067] S100: Collect the ambient temperature and internal temperature of each branch 1 in the multiple parallel branches 1 of the battery system 10, each of which has a battery pack, and determine the external and internal temperature difference of each branch 1 based on the ambient temperature and internal temperature of each branch 1.

[0068] The internal temperature of branch 1, also known as the self-temperature of branch 1, refers to the temperature inside branch 1 (or its own temperature), which can be determined by collecting the temperature of the individual cells in the battery pack on branch 1. The ambient temperature of branch 1 refers to the temperature of the environment in which branch 1 is located, i.e., the external temperature of branch 1. The temperature difference between the inside and outside of branch 1 is determined based on the difference between the ambient temperature and the internal temperature of branch 1. For example, in some embodiments, the temperature difference between the inside and outside of branch 1 is the difference between the ambient temperature and the internal temperature of branch 1 at a single point, that is, the temperature difference between the inside and outside of branch 1 is equal to the ambient temperature of branch 1 at a single point minus the internal temperature of branch 1 at a single point; or, the temperature difference between the inside and outside of branch 1 is the difference between the average of the ambient temperature of branch 1 at multiple points and the average of the internal temperature of branch 1 at multiple points, that is, the temperature difference between the inside and outside of branch 1 is equal to the average of the ambient temperature of branch 1 at multiple points minus the average of the internal temperature of branch 1 at multiple points.

[0069] In this application, the average internal temperature of branch 1 at multiple points is called the average internal temperature of branch 1. It can be obtained by collecting temperature data at multiple points inside branch 1 and then taking the average value. Similarly, the average ambient temperature of branch 1 at multiple points is called the average ambient temperature of branch 1. It can be obtained by collecting temperature data at multiple points in the environment where branch 1 is located and then taking the average value.

[0070] Compared to collecting the ambient and internal temperatures of branch 1 at a single point, collecting the ambient and internal temperatures of branch 1 at multiple points allows for a more accurate determination of these temperatures. This, in turn, facilitates more precise temperature control of branch 1 and enables more effective battery thermal management. For example, determining the external-internal temperature difference of each branch 1 based on its average ambient and internal temperatures allows for a more accurate assessment of this difference. Consequently, based on step S200, this facilitates more precise temperature regulation of branch 1 and more effectively reduces the impact of ambient temperature variations.

[0071] The ambient temperature of each branch 1 at multiple points can be determined by collecting temperature data at multiple points in the environment where each branch 1 is located; alternatively, before collecting the ambient temperature of each branch 1 at multiple points, the multiple parallel branches 1 can be divided into multiple temperature domains 5 according to the different environmental thermal characteristics, so that branches 1 with consistent environmental thermal characteristics are in the same temperature domain 5. Consistent environmental thermal characteristics include ambient temperatures within the same temperature range. Then, during the process of collecting the ambient temperature of each branch 1 at multiple points, the ambient temperature of each temperature domain 5 at multiple points is also collected, and the ambient temperature of each temperature domain 5 at multiple points is taken as the ambient temperature of each branch 1 at multiple points within each temperature domain 5. In the latter method, it is not necessary to set up multiple temperature collection points in the environment of each branch 1 to determine the multi-point ambient temperature of each branch 1. Instead, it is only necessary to divide the branches with similar ambient temperatures into the same temperature domain, set up multiple temperature collection points in each temperature domain, and use the collected multi-point ambient temperatures of the temperature domain as the multi-point ambient temperatures of each branch 1 in the same temperature domain. This method can determine the multi-point ambient temperature of each branch 1 more accurately, and requires fewer ambient temperature collection points, which can reduce the number of temperature sensors and the amount of data collected, and reduce the difficulty of data processing. Therefore, it can simplify the structure and save costs, enabling accurate determination of the multi-point ambient temperature and average ambient temperature of each branch 1 based on a simpler structure and lower cost.

[0072] S200. When the temperature difference between the outside and inside of branch 1 is greater than the temperature difference threshold, the temperature of branch 1 is adjusted so that branch 1 meets the preset conditions. The preset conditions include that the temperature difference between the outside and inside of branch 1 is less than or equal to the preset temperature difference value, and the preset temperature difference value is less than or equal to the temperature difference threshold.

[0073] The temperature difference threshold is the preset upper limit of the external and internal temperature difference of branch 1. The preset temperature difference value is the maximum value of the external and internal temperature difference of branch 1 when the preset temperature control meets the standard. Since the preset temperature difference value is less than or equal to the temperature difference threshold, making the external and internal temperature difference of branch 1 less than or equal to the preset temperature difference value will ensure that the external and internal temperature difference of branch 1 is less than or equal to the temperature difference threshold and does not exceed the limit.

[0074] In steps S100 and S200, during battery thermal management, the ambient temperature of the parallel branches is taken into consideration. Not only is the ambient temperature of each branch 1 in the parallel branch 1 collected, but also the external-internal temperature difference of each branch is determined based on the ambient and internal temperatures of each branch 1. Temperature regulation is applied to branches 1 whose external-internal temperature difference is greater than a temperature difference threshold, so that the corresponding branch 1 meets the preset condition that the external-internal temperature difference of the branch 1 is less than or equal to a preset temperature difference value. In this way, the external-internal temperature difference of each branch 1 is less than or equal to the preset temperature difference value, effectively reducing the impact of the difference in ambient temperature between parallel branches, mitigating the temperature difference amplification effect between parallel branches, improving the consistency between parallel branches (e.g., the consistency of internal resistance between parallel branches), and preventing some branches from falling into a vicious cycle of "temperature rise-increase internal resistance-increase current-increase temperature rise" and thus drastically shortening their lifespan. Therefore, the performance of the battery system 10 can be effectively improved.

[0075] As can be seen, steps S100 and S200 can effectively take into account the difference in ambient temperature between branches during the thermal management of the battery system 10 including parallel branches, reduce the temperature difference amplification effect between parallel branches, improve the consistency between parallel branches, extend the life of each branch in the parallel branches, and improve the performance of the battery system 10.

[0076] In some embodiments, the preset conditions include not only that the external and internal temperature difference of branch 1 is less than or equal to a preset temperature difference value, but also that the average internal temperature of branch 1 is less than or equal to a preset average temperature value, and / or that the highest internal temperature of branch 1 is less than or equal to a preset high temperature value. Wherein, the highest internal temperature of branch 1 is the maximum value among multiple points of internal temperature of branch 1. The preset average temperature value and the preset high temperature value are the maximum values ​​of the average internal temperature and the highest average temperature of branch 1, respectively, when the temperature control meets the target.

[0077] Based on the above settings, when the external and internal temperature difference of branch 1 is greater than the temperature difference threshold, the temperature of branch 1 is regulated. This not only makes the external and internal temperature difference of branch 1 less than or equal to the preset temperature difference value, but also makes the average temperature of branch 1 less than or equal to the preset average temperature value, and / or makes the highest internal temperature of branch 1 less than or equal to the preset high temperature value. In this way, not only can the external and internal temperature difference of each branch 1 be controlled to be less than or equal to the preset temperature difference value, reducing the difference in external and internal temperature difference between branches 1, but also the average internal temperature of each branch 1 can be controlled to be less than or equal to the preset average temperature value and / or the highest internal temperature can be controlled to be less than or equal to the preset high temperature value, reducing the difference in average internal temperature and / or highest internal temperature between branches 1. This further reduces the temperature difference between each parallel branch 1, improves the consistency between each parallel branch 1, reduces the temperature difference amplification effect between parallel branches, extends the life of each branch in the parallel branches, and improves the performance of the battery system 10.

[0078] Furthermore, in some embodiments, temperature regulation is applied to branch 1 not only when the external and internal temperature difference of branch 1 exceeds a temperature difference threshold to ensure branch 1 meets preset conditions, but also when the average internal temperature of branch 1 exceeds a uniform temperature threshold and / or the highest internal temperature of branch 1 exceeds a high temperature threshold. This provides richer and more comprehensive activation conditions for temperature regulation, more effectively reducing temperature differences between parallel branches 1, improving consistency among parallel branches 1, mitigating the temperature difference amplification effect between parallel branches, extending the lifespan of each branch in the parallel network, and improving the performance of the battery system 10.

[0079] When the average internal temperature of branch 1 exceeds the average temperature threshold, i.e., when branch 1 is temperature-regulated to meet preset conditions, these preset conditions may include the average internal temperature of branch 1 being less than or equal to a preset average temperature value. This is to more effectively reduce the average internal temperature difference between branches 1, improve the consistency between parallel branches 1, mitigate the temperature difference amplification effect between parallel branches, extend the lifespan of each branch in the parallel branches, and improve the performance of the battery system 10. In this case, the preset average temperature value is less than or equal to the average temperature threshold.

[0080] When the highest internal temperature of branch 1 exceeds the high-temperature threshold, i.e., when branch 1 is temperature-regulated to meet preset conditions, these preset conditions may include the highest internal temperature of branch 1 being less than or equal to a preset high-temperature value. This is to more effectively reduce the difference in the highest internal temperature between branches 1, improve the consistency between parallel branches 1, mitigate the temperature difference amplification effect between parallel branches, extend the lifespan of each branch in the parallel branches, and improve the performance of the battery system 10. In this case, the preset high-temperature value is less than or equal to the high-temperature threshold.

[0081] In the foregoing embodiments, temperature control of branch 1 may include:

[0082] Adjust the coolant flow rate in the cooling path used for cooling branch 1.

[0083] By adjusting the coolant flow rate in the cooling flow path used for cooling branch 1, the cooling intensity of the cooling flow path on branch 1 can be adjusted, thereby adjusting the temperature of branch 1.

[0084] Specifically, in some embodiments, adjusting the coolant flow rate in the cooling path for cooling branch 1 includes:

[0085] Adjust the opening of the control valve used to control the flow rate of coolant in the cooling flow path.

[0086] The opening degree of the control valve used to control the flow rate of coolant in the cooling flow path affects the flow rate of coolant in the cooling flow path, and thus affects the cooling intensity. Therefore, adjusting the control valve opening degree can achieve temperature control of branch 1.

[0087] When the temperature of branch 1 is controlled by adjusting the opening of the control valve, it is crucial to determine the target opening of the control valve (i.e., the opening that the control valve needs to be adjusted to). This directly affects the accuracy of temperature control in branch 1, and consequently, whether the consistency between branches can be effectively improved, thus enhancing the performance of the battery system 10.

[0088] In some embodiments, during the adjustment of the control valve opening, the temperature difference between the inside and outside of branch 1 is used as a basis. Determine the target opening degree of the control valve. Specifically, in some embodiments, based on the temperature difference between the inside and outside of branch 1. Determine the target opening degree of the control valve. At that time, based on the temperature difference between the inside and outside of branch 1 With coefficient The product (i.e.) Determine the target opening degree of the control valve. In this way, the target opening degree of the control valve is... Temperature difference between the inside and outside of branch 1 The size is related, which can more effectively adjust the temperature difference between the outside and inside of the branch 1, and make it easier to adjust the temperature difference between the outside and inside of the branch 1 to be less than or equal to the preset temperature difference value, reduce the temperature difference between the outside and inside of the branches, improve the consistency between the branches, and improve the performance of the battery system 10.

[0089] Furthermore, in some embodiments, it is not only based on the temperature difference between the inside and outside of branch 1. To determine the target opening degree of the control valve Furthermore, it is based on the average internal temperature of branch 1. The highest internal temperature of branch 1 and the basic opening of the control valve To determine the target opening degree of the control valve, at least one of the following must be selected. In this way, the target opening degree of the control valve is... Not only the temperature difference between the inside and outside of branch 1 The size is related to, and also to, the average internal temperature of branch 1. The highest internal temperature of branch 1 and the basic opening of the control valve The temperature of branch 1 can be more effectively adjusted by at least one of the following: it is not only easier to adjust the temperature difference between the outside and inside of branch 1 to be less than or equal to the preset temperature difference value, but also easier to adjust at least one of the average internal temperature and the highest internal temperature of branch 1 to the required value. Therefore, it is more conducive to reducing the temperature difference between branches, improving the consistency between branches, and improving the performance of battery system 10.

[0090] Specifically, in some embodiments, based on the average internal temperature of branch 1 Determine the target opening degree of the control valve. At that time, based on the average internal temperature of branch 1 The target value of the average internal temperature of branch 1 The difference (i.e.) Determine the target opening degree of the control valve. For example, in some embodiments, based on the average internal temperature of branch 1... The target value of the average internal temperature of branch 1 The difference determines the target opening degree of the control valve. At that time, based on the average internal temperature of branch 1 The target value of the average internal temperature of branch 1 Difference and coefficient The product (i.e.) Determine the target opening degree of the control valve. In this way, the target opening degree of the control valve is related to the difference between the average internal temperature of branch 1 and the target value of the average internal temperature of branch 1, making it easier to adjust the average internal temperature of branch 1 to the required level. Therefore, it is more conducive to reducing the temperature difference between branches, improving the consistency between branches, and improving the performance of battery system 10.

[0091] Additionally, in some embodiments, based on the highest internal temperature of branch 1 Determine the target opening degree of the control valve. At that time, based on the highest internal temperature of branch 1 The target value of the highest internal temperature of branch 1 The difference (i.e.) Determine the target opening degree of the control valve. For example, in some embodiments, based on the highest internal temperature of branch 1... The target value of the highest internal temperature of branch 1 The difference (i.e.) Determine the target opening degree of the control valve. At that time, based on the highest internal temperature of branch 1 The target value of the highest internal temperature of branch 1 Difference and coefficient The product (i.e.) Determine the target opening degree of the control valve. In this way, the target opening degree of the control valve is related to the difference between the highest internal temperature of branch 1 and the target value of the highest internal temperature of branch 1, making it easier to adjust the highest internal temperature of branch 1 to the required value. Therefore, it is more conducive to reducing the temperature difference between branches, improving the consistency between branches, and improving the performance of battery system 10.

[0092] As an example, in some embodiments, the difference between the average internal temperature of branch 1 and the target value of the average internal temperature of branch 1 and the coefficient are used. The product (i.e.) The difference between the highest internal temperature of branch 1 and the target value of the highest internal temperature of branch 1, and the coefficient. The product (i.e.) and the basic opening degree of the control valve At least one of them has a temperature difference between the inside and outside of branch 1 and a coefficient. The product (i.e.) The sum of these factors determines the target opening degree of the control valve. This allows for more convenient and precise adjustment of the control valve opening, regulation of the temperature of branch 1, reduction of temperature differences between branches, improvement of consistency between branches, and enhancement of the performance of the battery system 10.

[0093] In some embodiments, the temperature of branch 1 is regulated for a maximum duration. If time If branch 1 still fails to meet the preset conditions, then temperature control of branch 1 is stopped. This limits the time of temperature control, ensuring that the temperature control time does not exceed the set time. Convenient for time If internal temperature control fails to achieve the desired control effect, temperature control should be stopped immediately and other measures should be taken.

[0094] In some embodiments, It is a constant; or, based on the average internal temperature of branch 1. and highest internal temperature At least one of them, determine Among them, when based on the average internal temperature of branch 1 and highest internal temperature At least one of them, determine Time It is not a constant, but varies with the average internal temperature of branch 1. and highest internal temperature At least one of the changes in is determined in this way. The value is more in line with actual needs and makes it easier and more accurate to control the maximum time for temperature regulation of branch 1.

[0095] In some embodiments, based on the average internal temperature of branch 1 When t is determined, the average internal temperature of branch 1 is used as the basis. The target value of the average internal temperature of branch 1 The difference (i.e.) ), determine t. For example, in some embodiments, the average internal temperature of branch 1 is... The target value of the average internal temperature of branch 1 The difference, when t is determined, is based on the average internal temperature of branch 1. The target value of the average internal temperature of branch 1 Difference and coefficient The product (i.e.) ), and determine t. In this way, time t is related to the difference between the average internal temperature of branch 1 and the target value of the average internal temperature of branch 1, making it easier to accurately control the maximum time for temperature regulation of branch 1.

[0096] Additionally, in some embodiments, based on the highest internal temperature of branch 1 When t is determined, the highest internal temperature of branch 1 is used as the basis. The target value of the highest internal temperature of branch 1 The difference (i.e.) ), determine t. For example, in some embodiments, at the highest internal temperature of branch 1 The target value of the highest internal temperature of branch 1 The difference, when t is determined, is based on the highest internal temperature of branch 1. The target value of the highest internal temperature of branch 1 Difference and coefficient The product (i.e.) ), determine t. Thus, time t is related to the highest internal temperature of branch 1. The target value of the highest internal temperature of branch 1 The difference makes it easier and more accurate to control the maximum time for temperature regulation of branch 1.

[0097] In some embodiments, it is based not only on the average internal temperature of branch 1 and highest internal temperature At least one of them, determine Moreover, it is based on base time. ,Sure For example, in some embodiments, the difference between the average internal temperature of branch 1 and the target value of the average internal temperature of branch 1 is used as a coefficient. The product of the product and the difference between the highest internal temperature of branch 1 and the target value of the highest internal temperature of branch 1, and the coefficient. At least one of the products of the base time The sum, determine That is, based on and At least one of them is related to the base time. The sum, determine This allows for more accurate and convenient time determination. The size of the branch effectively controls the longest time for temperature regulation of branch 1.

[0098] In some embodiments, if time If branch 1 still fails to meet the preset conditions after this process, not only will temperature control of branch 1 be stopped, but current will also be distributed among branches 1 to ensure that each branch 1 meets the preset conditions. This allows for adjustments to the temperature control duration. If the consistency between branches still fails to meet requirements, and there are significant temperature differences, resistance differences, and current differences between branches, temperature control should be stopped immediately. Instead, active current distribution between branches should be implemented to reduce current differences and improve consistency. This forms a hierarchical control system of first controlling temperature (also known as temperature compensation) and then distributing current (also known as current compensation). In this way, the battery thermal management process can consider not only the impact of ambient temperature differences but also the impact of charging and discharging processes on the thermal characteristics of the battery pack. This effectively solves the problem of battery self-heating coupled with ambient temperature during charging and discharging, and the inability of traditional current distribution strategies to adapt to real-time internal resistance changes. It can effectively improve consistency between branches, avoid the bottleneck effect of abnormal branches, extend battery life, and improve battery system performance.

[0099] In some embodiments, when distributing current among branches 1, the average internal temperature of branch 1 is used as a basis. and remaining battery power Determine the current in branch 1 from at least one of the following. Specifically, in some embodiments, based on the average internal temperature of branch 1... and remaining battery power Determine the current in branch 1 from at least one of the following. At that time, based on the average internal temperature of all parallel branches 1 Average internal temperature of branch 1 The difference (i.e.) - ) and the average remaining power of all branches 1 Remaining power of branch 1 The difference (i.e.) Determine the current in branch 1 from at least one of the following: In this way, during the current distribution process, the current of each branch is related to its own internal average temperature and remaining charge, which can more accurately determine the current required to be distributed to each branch, more effectively improve the consistency between branches, and improve the performance of the battery system 10.

[0100] In addition, in some embodiments, a PID algorithm is used to distribute current among the branches 1. For example, in some embodiments, the current of branch 1 is determined according to the following formula. :

[0101]

[0102] in, The base current is equal to the total current divided by the number of branches. The average internal temperature of all branches 1, The average internal temperature of branch 1, The average remaining power of all branch 1, The remaining power of branch 1, , and These are PID parameters.

[0103] In the above embodiment, based on the average internal temperature of all parallel branches 1 Average internal temperature of branch 1 The difference (i.e.) - ), average remaining power of all branch 1 Remaining power of branch 1 The difference (i.e.) and base current The PID algorithm is used to dynamically adjust the current of branch 1 to realize the distribution of current among branches. This can more effectively improve the current consistency among branches, extend the life of battery system 10, and improve the performance of battery system 10.

[0104] See Figure 1 In order to achieve the current compensation in the above embodiments, a converter 3 can be set between branch 1 and load terminal 4 or charging terminal (not shown) to isolate branch 1 from load terminal 4 or charging terminal (not shown). The current is distributed through converter 3 so that the current of branch 1 is no longer completely affected by load terminal 4 or charging terminal, but can be actively distributed.

[0105] In some embodiments, if current distribution among branches 1 still fails to meet preset conditions, the abnormal branch 1 is isolated using one of the following methods: current limiting, powering off the abnormal branch 1, or powering off the battery system 10. This allows for timely cessation of current distribution and initiation of active isolation of the abnormal branch when current distribution fails to meet the required consistency. This prevents the abnormal branch from exacerbating differences between branches, forming a tiered control system: first temperature regulation (also known as temperature compensation), then current distribution (also known as current compensation), and finally offline isolation. This approach more effectively and promptly avoids the bottleneck effect of abnormal branches, extending battery system life and improving battery system performance.

[0106] The three methods used to isolate abnormal branches are current limiting, abnormal branch power-off, and battery system power-off. These methods can be used when the fault level of abnormal branch 1 is a first-level fault, a second-level fault, and a third-level fault, respectively. The types of abnormalities in branch 1 corresponding to the first-level fault, second-level fault, and third-level fault increase in that order.

[0107] For example, in some embodiments, the types of abnormalities that may occur in a branch include: (1) the average temperature of the branch is too high; (2) the temperature of a single cell in the branch is too high; (3) the cumulative temperature rise of the branch is too high; (4) the temperature rise rate of the branch is too fast; (5) the temperature difference between clusters is too large; and (6) communication abnormality or interruption, etc. According to the order of the number of abnormalities in the branch from few to many, the fault level is divided into a first fault level, a second fault level and a third fault level from light to severe, and the first fault level, the second fault level and the third fault level correspond to the three isolation methods of current limiting, abnormal branch power-off and battery system power-off, respectively.

[0108] In the above embodiments, the isolation methods are selected sequentially according to the severity of the abnormal branch faults, from lightest to most severe, following the order of current limiting – power-off of the abnormal branch – power-off of the battery system. When there are few types of branch faults and the fault level is low (corresponding to the first fault level), current limiting is used for isolation. When there are medium types of branch faults and the fault level is medium (corresponding to the second fault level), power-off of the abnormal branch is used for isolation. When there are many types of branch faults and the fault level is high (corresponding to the third fault level), power-off of the battery system is used for isolation. This allows for the implementation of corresponding isolation measures according to the fault level, achieving a graded response mechanism in cases of rapid temperature rise or communication abnormalities. This effectively reduces the risk of battery system failure under extreme conditions and improves the safety performance of the battery system.

[0109] Based on the battery thermal management methods of the foregoing embodiments, this application also provides a controller. The controller includes a memory and a processor coupled to the memory, the processor being configured to execute the battery thermal management method of any embodiment based on instructions stored in the memory.

[0110] Additionally, this application provides a mechanical system including a battery system 10 and a controller according to any embodiment. Furthermore, in some embodiments, the battery system 10 further includes a converter 3 electrically connected between the branch 1 and the load terminal 4 and / or the charging terminal. The mechanical system can be a large-tonnage piece of equipment such as construction machinery, and its battery system 10 can be a high-capacity battery system.

[0111] The following will provide further details. Figures 1-4 The example shown.

[0112] like Figures 1-2As shown, in this embodiment, the mechanical system is an engineering vehicle, and its battery system 10 includes multiple parallel branches 1 (eight in this example). These parallel branches 1 are distributed in different locations such as the frame and chassis, where the ambient temperature varies considerably, and each branch includes a battery pack with individual cells. The number of battery packs on each branch can be the same or different; for example, in some embodiments, some branches have a single battery pack, while others have multiple battery packs connected in series. Figure 1 In the diagram, these parallel branches are labeled 1#, 2#, ..., and can be referred to as branch 1, branch 2, ... for ease of description.

[0113] To facilitate thermal management of each branch 1, such as Figure 2 As shown, in this embodiment, the battery system 10 further includes a temperature acquisition module 21 and an electrical acquisition module 22, which respectively acquire the temperature signal and electrical signal of the branch 1. The temperature acquisition module 21 includes a temperature sensor (which may be called an ambient temperature sensor) disposed in the environment for acquiring the ambient temperature, and a temperature sensor (which may be called an internal temperature sensor) disposed inside the branch 1 for acquiring the internal temperature of the branch.

[0114] And, as Figure 2 As shown, in this embodiment, a converter 3 is provided between branch 1 and load terminal 4 to isolate branch 1 and load terminal 4, facilitating current distribution. Figure 2 In this circuit, there is not a one-to-one correspondence between branch 1 and converter 3. Instead, some branches 1 share a single converter 3. However, it is understandable that this is not the only way to configure converter 3.

[0115] right Figures 1-2 The battery system 10, in this embodiment, employs a three-level control strategy of "temperature compensation – current compensation – fault isolation" based on temperature domain division for battery thermal management. The battery thermal management method combines... Figures 3-4 This will be explained.

[0116] (I) Temperature Domain Division

[0117] like Figure 3 As shown, based on the physical distribution of multiple parallel branches 1 on the vehicle (considering the sunlight 6, the obstruction 7, and the airflow 8 at the distribution locations) and the temperature field distribution results of the vehicle thermal simulation, the multiple parallel branches 1 are divided into several independent temperature domains 5 (e.g., Figure 3 The first temperature domain 51, the second temperature domain 52, and the third temperature domain 53 shown have branches within each temperature domain 5 that have consistent (identical or similar) environmental thermal characteristics. For example, Figure 3In the first temperature domain 51, the ambient temperature of each branch 1 is within a temperature range greater than or equal to the first temperature value. In the second temperature domain 52, the ambient temperature of each branch 1 is within a temperature range less than the first temperature value but greater than or equal to the second temperature value. In the third temperature domain 53, the ambient temperature of each branch 1 is within a temperature range less than the second temperature value. In this case, the first temperature domain 51, the second temperature domain 52, and the third temperature domain 53 can also be referred to as the high-temperature domain, the medium-temperature domain, or the low-temperature domain, respectively. In other embodiments, the environmental thermal characteristics are consistent, including not only that the ambient temperature is within the same temperature range, but also that the ambient temperature changes are similar, for example, the changes in ambient temperature throughout the day are not significantly different.

[0118] For each temperature range 5, ambient temperature sensors are deployed at multiple typical locations to collect the ambient temperature within that range, thus obtaining the ambient temperature at multiple points. Marked as ( =1, 2, 3… , This represents the number of ambient temperature monitoring points in temperature domain 5. =1, 2, 3… , (This refers to the number of temperature domains 5 in the battery system 10). Furthermore, multiple internal temperature sensors are installed inside each branch 1 to collect the temperature of multiple cells on each branch 1, obtaining the internal temperature of each branch 1 at multiple points. Marked as ( =1, 2, 3… , The number of temperature detection points in branch 1; =1, 2, 3… , (This refers to the number of branch 1s in temperature domain 5).

[0119] Define temperature range The average ambient temperature is: =( ) / .

[0120] Define temperature range Middle Branch Road The average internal temperature is: =( ) / .

[0121] Define temperature range Middle Branch Road The highest temperature is: .

[0122] Define temperature range Middle Branch Road The temperature difference between the inside and outside is: .

[0123] (II) Primary Regulation: Temperature Compensation

[0124] Each branch 1 is equipped with an independent liquid-cooled branch and a control valve (e.g., a solenoid valve). The opening degree of the control valve can be adjusted by analog or digital signals.

[0125] Conditions for triggering temperature compensation:

[0126] 1) The average internal temperature of the branch circuit exceeds the limit: ( (The preset average temperature threshold).

[0127] 2) The maximum internal temperature of the branch circuit exceeds the limit: ( (The preset high temperature threshold).

[0128] 3) The temperature difference between the inside and outside of the branch road exceeds the limit: ( (This is a preset temperature difference threshold).

[0129] When any of the above conditions are met, increase the opening of the control valve in the corresponding branch 1. The adjustment formula is as follows:

[0130]

[0131] in, Temperature range Middle Branch Road The target opening degree of the corresponding control valve, To control the reference opening degree of the valve, Temperature range Middle Branch Road The target value for the internal average temperature, Temperature range Middle Branch Road The target value for the highest internal temperature; , and This is the proportional adjustment coefficient, obtained through experimental calibration.

[0132] Set temperature compensation time , It can be obtained through the following formula:

[0133]

[0134] in, Based on the basic compensation time, and This is the time coefficient corresponding to the temperature deviation.

[0135] In time inside, if (Preset average temperature value) (Preset high temperature value) and (If the preset temperature difference value is reached, temperature compensation will stop.)

[0136] in, , and Determined based on unit energy consumption, simulated operating conditions, and actual vehicle calibration.

[0137] If time exceeds If the above conditions are still not met, then secondary regulation will be triggered.

[0138] (III) Secondary regulation: Current compensation

[0139] When the consistency between branches is disrupted and their resistances differ, simply increasing external cooling intensity cannot effectively solve the temperature difference problem between branches, which can easily induce individual component isolation and lead to more serious consequences. To address this issue, this embodiment employs a current balancing method based on current compensation.

[0140] based on Figure 3 The converter 3 shown in this embodiment uses a PID algorithm for dynamic adjustment to achieve current distribution. For the temperature domain... Middle Branch Road The current distribution formula is as follows:

[0141]

[0142] in:

[0143] Temperature range Middle Branch Road The target current, Reference current (total current / number of branches);

[0144] The average internal temperature of all branches, The average remaining power of all branches, Temperature range Middle Branch Road The remaining battery power;

[0145] , and These are PID parameters, obtained through actual vehicle calibration.

[0146] While performing secondary regulation and balancing the current, regulation can also be combined with the consistency of electrical charge between branches. This can be achieved by adopting methods such as active balancing or active discharge to reduce the difference in electrical charge between branches during current distribution. For example, if some branches are current-limited, their remaining charge (SOC, State of Charge) may be large. In this case, the branches can be connected so that the branch with the larger SOC can compensate the branch with the smaller SOC, maintaining the consistency of SOC between branches.

[0147] (iv) Three-level control: fault isolation

[0148] When both temperature and current compensation are ineffective, considering the risk of thermal runaway induced by battery malfunction or internal problems, it is necessary to actively isolate the abnormal branch. When the branch meets one or more of the following conditions, corresponding countermeasures should be implemented in sequence according to the fault level.

[0149] The judgment conditions are as follows: 1) The average temperature of the branch is too high; 2) The temperature of a single unit in the branch is too high; 3) The cumulative temperature rise of the branch is too high; 4) The temperature rise rate of the branch is too fast; 5) The temperature difference between branches is too large; 6) Communication is abnormal or interrupted, etc. At this time, the different fault levels are handled in the order of current limiting - powering off the faulty branch - powering off the system.

[0150] As can be seen, this embodiment, in the process of thermal management of a battery system including multiple parallel branches, considers the ambient temperature differences between branches and the dynamic impact of the charging and discharging process on the thermal characteristics of the battery pack. It provides a more comprehensive understanding of the state and causes of the battery system, and by combining the division of temperature domains with a three-level control strategy of "temperature compensation - current compensation - fault isolation," it can effectively solve the following problems:

[0151] 1) Multi-branch parallel temperature difference amplification effect: When the temperature of a branch increases, the internal resistance decreases, the current shunting increases, forming a positive feedback of temperature rise, which in turn aggravates the temperature difference between branches;

[0152] 2) Dynamic interference during charging and discharging: During the charging and discharging process, the battery's self-heating is coupled with the ambient temperature, and the traditional fixed current distribution strategy cannot adapt to real-time changes in internal resistance;

[0153] 3) Risk of loss of control under extreme operating conditions: Existing temperature control methods lack a graded response mechanism when the temperature rises too quickly or communication is abnormal, which can easily lead to system-level failures.

[0154] Therefore, it can effectively avoid the bottleneck effect of abnormal branches, improve the consistency between parallel branches, and improve the performance of the battery system.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them; although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this application or equivalent substitutions can be made to some technical features, all of which should be covered within the scope of the technical solutions claimed in this application.

Claims

1. A method of battery thermal management, the method comprising: include: Collect the ambient and internal temperatures of each branch (1) of the battery system (10) which are connected in parallel and each has a battery pack, and determine the external and internal temperature difference of each branch (1) based on the ambient and internal temperatures of each branch (1). When the temperature difference between the outside and inside of the branch (1) is greater than the temperature difference threshold, the temperature of the branch (1) is adjusted so that the branch (1) meets the preset conditions. The preset conditions include that the temperature difference between the outside and inside of the branch (1) is less than or equal to the preset temperature difference value, and the preset temperature difference value is less than or equal to the temperature difference threshold.

2. The battery thermal management method of claim 1, wherein, The ambient and internal temperatures of each branch (1) in the multiple parallel branches (1) are collected, and the external and internal temperature differences of each branch (1) are determined based on the ambient and internal temperatures of each branch (1), including: Collect the internal temperature and ambient temperature of each branch (1) at multiple points, and determine the temperature difference between the inside and outside of each branch (1) based on the average ambient temperature and average internal temperature of each branch (1). Among them, the average internal temperature of each branch (1) is the average internal temperature of each branch (1) at multiple points, and the highest internal temperature of each branch (1) is the maximum internal temperature of each branch (1) at multiple points.

3. The battery thermal management method according to claim 2, characterized in that, Before collecting the ambient temperature of each branch (1) at multiple points, the multiple parallel branches (1) are divided into multiple temperature domains (5) according to the different ambient thermal characteristics, so that the branches (1) with consistent ambient thermal characteristics are in the same temperature domain (5), and the consistent ambient thermal characteristics include the ambient temperature being in the same temperature range. During the process of collecting the ambient temperature of each branch (1) at multiple points, the ambient temperature of each temperature domain (5) at multiple points is collected, and the ambient temperature of each temperature domain (5) at multiple points is used as the ambient temperature of each branch (1) at multiple points within each temperature domain (5).

4. The battery thermal management method of claim 1, wherein, The preset conditions also include: The average internal temperature of the branch (1) is less than or equal to a preset average temperature value, wherein the average internal temperature of the branch (1) is the average of the internal temperatures of the branch (1) at multiple points; and / or, The highest internal temperature of the branch (1) is less than or equal to a preset high temperature value, wherein the highest internal temperature of the branch (1) is the maximum value of the internal temperature of the branch (1) at multiple points.

5. The battery thermal management method of claim 1, wherein, The battery thermal management method further includes at least one of the following: When the average internal temperature of the branch (1) exceeds the average temperature threshold, the branch (1) is temperature regulated so that the branch (1) meets the preset conditions. The preset conditions also include that the average internal temperature of the branch (1) is less than or equal to the preset average temperature value, the preset average temperature value is less than or equal to the average temperature threshold, and the average internal temperature of the branch (1) is the average of the internal temperatures of the branch (1) at multiple points. When the highest internal temperature of the branch (1) exceeds the high temperature threshold, the temperature of the branch (1) is regulated so that the branch (1) meets the preset conditions. The preset conditions also include that the highest internal temperature of the branch (1) is less than or equal to a preset high temperature value, the preset high temperature value is less than or equal to the high temperature threshold, and the highest internal temperature of the branch (1) is the maximum value of the internal temperature of the branch (1) at multiple points.

6. The battery thermal management method of any one of claims 1-5, wherein, Temperature control of the branch (1) includes: Adjust the flow rate of coolant in the cooling flow path used to cool the branch (1).

7. The battery thermal management method of claim 6, wherein, Adjusting the coolant flow rate in the cooling path used to cool the branch (1) includes: Adjust the opening degree of the control valve used to control the flow rate of coolant in the cooling flow path.

8. The battery thermal management method of claim 7, wherein, During the process of adjusting the opening of the control valve, the target opening of the control valve is determined based on the temperature difference between the inside and outside of the branch (1).

9. The battery thermal management method of claim 8, wherein, When determining the target opening degree of the control valve based on the outside-inside temperature difference of the branch (1), the target opening degree of the control valve is determined based on the product of the outside-inside temperature difference of the branch (1) and a coefficient .

10. The battery thermal management method of claim 8, wherein, The target opening of the control valve is determined based on at least one of the average internal temperature of the branch (1), the highest internal temperature of the branch (1), and the basic opening of the control valve, wherein the average internal temperature of the branch (1) is the average of the internal temperatures of the branch (1) at multiple points, and the highest internal temperature of the branch (1) is the maximum value of the internal temperatures of the branch (1) at multiple points.

11. The battery thermal management method of claim 10, wherein, When determining the target opening of the control valve based on the average internal temperature of the branch (1), the target opening of the control valve is determined based on the difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1); and / or, when determining the target opening of the control valve based on the highest internal temperature of the branch (1), the target opening of the control valve is determined based on the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1).

12. The battery thermal management method of claim 11, wherein, When determining the target opening degree of the control valve based on the difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1), the difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1) and the coefficient are used. The product of the product is used to determine the target opening of the control valve; and / or, when determining the target opening of the control valve based on the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1), the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1) is used as the factor. The target opening degree of the control valve is determined by the product of the product of the two values.

13. The battery thermal management method of claim 12, wherein, The difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1) and the coefficient The product of, the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1), and the coefficient. The product of and at least one of the basic opening of the control valve and the external and internal temperature difference of the branch (1) and the coefficient The sum of the products determines the target opening degree of the control valve.

14. The battery thermal management method of any one of claims 1-5, wherein, Temperature regulation of the branch (1) for a maximum duration If time If the branch (1) still fails to meet the preset conditions, then the temperature control of the branch (1) will be stopped.

15. The battery thermal management method of claim 14, wherein, It is a constant; or, determined based on at least one of the average internal temperature and the highest internal temperature of the branch (1). The average internal temperature of the branch (1) is the average internal temperature of the branch (1) at multiple points, and the highest internal temperature of the branch (1) is the maximum internal temperature of the branch (1) at multiple points.

16. The battery thermal management method of claim 15, wherein, When t is determined based on the average internal temperature of the branch (1), t is determined based on the difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1); and / or, when t is determined based on the highest internal temperature of the branch (1), t is determined based on the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1).

17. The battery thermal management method of claim 16, wherein, When t is determined based on the difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1), the coefficient is calculated based on the difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1). The product of and , determines t; and / or, when determining t based on the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1), the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1) and the coefficient The product of and determines t.

18. The battery thermal management method of claim 15, wherein, Also based on the base time , it is determined .

19. The battery thermal management method of claim 18, wherein, The difference between the average internal temperature of the branch (1) and the target value of the average internal temperature of the branch (1) and the coefficient The product of the product and the difference between the highest internal temperature of the branch (1) and the target value of the highest internal temperature of the branch (1) and the coefficient. At least one of the products of the base time The sum of the numbers determines the outcome. .

20. The battery thermal management method of claim 14, wherein, If the time After the time, if the branch (1) still does not meet the preset condition, the temperature regulation of the branch (1) is stopped, and the current distribution among the branches (1) is performed to make the branches (1) meet the preset condition.

21. The battery thermal management method of claim 20, wherein, When distributing current among branches (1), the current of the branch (1) is determined based on at least one of the average internal temperature of the branch (1) and the remaining charge; and / or, a PID algorithm is used to distribute current among branches (1).

22. The battery thermal management method of claim 21, wherein, When determining the current of the branch (1) based on at least one of the average internal temperature and the remaining charge of the branch (1), the current of the branch (1) is determined based on at least one of the difference between the average internal temperature of all parallel branches (1) and the average internal temperature of the branch (1) and the difference between the average remaining charge of all branches (1) and the remaining charge of the branch (1).

23. The battery thermal management method of claim 22, wherein, When determining the current of a branch (1) based on the difference between the average internal temperature of all branches (1) and the average internal temperature of the branch (1), and the difference between the average remaining charge of all branches (1) and the remaining charge of the branch (1), the current of the branch (1) is determined according to the following formula. : in, It equals the total current divided by the number of branches. The average internal temperature of all branches (1) The average internal temperature of the branch (1), The average remaining charge of all branches (1), The remaining power of the branch (1) , and These are PID parameters.

24. The battery thermal management method of claim 20, wherein, If current distribution between branches (1) still fails to make each branch (1) meet the preset conditions, then one of the following methods—current limiting, power-off of abnormal branches, and power-off of the battery system—is used to isolate the abnormal branches.

25. The battery thermal management method of claim 24, wherein, The three methods of current limiting, abnormal branch power-off and battery system power-off are adopted when the fault level of the abnormal branch is a first-level fault, a second-level fault and a third-level fault, respectively. The abnormal types of the branches (1) corresponding to the first-level fault, the second-level fault and the third-level fault increase in sequence.

26. A controller characterized by The device includes a memory and a processor coupled to the memory, the processor being configured to execute the battery thermal management method as described in any one of claims 1-24 based on instructions stored in the memory.

27. A mechanical system comprising a battery system (10) comprising a plurality of parallel branches (1), each branch (1) comprising a battery pack with a single cell, characterized in that, The mechanical system also includes the controller as described in claim 26.

28. The mechanical system of claim 27, wherein, The battery system (10) also includes a converter (3) electrically connected between the branch (1) and the load terminal (4) and / or the charging terminal.

Images