Uninterruptible power supply system based on vehicle-mounted intelligent power supply management
By establishing a model of the relationship between the working current and temperature of lithium battery packs, dividing the battery pack into a central and semi-circular section, identifying the lithium battery packs that heat up the fastest, and setting alternating currents, the problem of uneven heat dissipation in vehicle-mounted lithium battery packs was solved, and uninterrupted power supply was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-07
AI Technical Summary
Existing vehicle-mounted lithium battery packs have difficulty in controlling heat dissipation according to the heat dissipation conditions of different locations, resulting in uneven temperature and affecting the continuity of power supply.
By establishing a model of the relationship between the working current and temperature of lithium battery packs, the battery pack is divided into a central part and two semi-circular parts. The lithium battery packs that heat up the fastest are identified, and the current is set alternately to ensure that the temperature is below the upper limit of the working temperature.
It enables targeted current control based on the heat dissipation of different lithium battery cells, avoiding overheating damage and ensuring uninterrupted power supply.
Smart Images
Figure CN121813658A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power management technology, specifically to an uninterruptible power supply system based on in-vehicle intelligent power management. Background Technology
[0002] Specialized vehicles are equipped with onboard specialized equipment. This equipment typically uses multiple lithium battery cells to form a battery pack for power. These battery cells operate with identical parameters. However, the heat dissipation of the battery cells varies depending on their location during operation. Heat dissipation is achieved through two methods: natural airflow generated by vehicle movement and control of the battery cell current. Existing battery regulation systems often use a uniform approach, making it difficult to tailor control based on varying heat dissipation levels. This results in excessively high temperatures within the battery pack, hindering continuous power supply. Summary of the Invention
[0003] To address the aforementioned technical problems, this technical solution provides an uninterruptible power supply system based on vehicle-mounted intelligent power management, which solves the problems mentioned in the background section.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Uninterruptible power supply (UPS) systems based on in-vehicle intelligent power management include: The parameter acquisition module acquires the battery pack used in the special vehicle, acquires the spatial arrangement of at least one lithium battery cell in the battery pack, and acquires a reference ratio of the area of the lithium battery cell exposed to the outside based on the spatial arrangement of the lithium battery cell. The data acquisition module obtains the upper limit of the operating temperature of the lithium battery pack and the total current usage of all lithium battery packs based on historical usage data. The model building module establishes a model of the relationship between the working current and the working temperature of the lithium battery pack, denoted as the fitting model. The data calculation module obtains the upper limit of the working current of the lithium battery block based on the fitting model and spatial arrangement position. It accumulates at least one upper limit of the working current to obtain the comprehensive upper limit of the current. The total current usage is divided by the comprehensive upper limit of the current to obtain the effective parameters. The battery control module, when the effective parameter does not exceed 1, multiplies the upper limit of the lithium battery cell's operating current by the effective parameter to obtain the actual operating current of the lithium battery cell. When the effective parameter exceeds 1, the battery pack is divided into a central part and two semi-circular parts, forming the actual operating current of the lithium battery cells in the semi-circular parts and the actual operating current of the lithium battery cells in the central part. The lithium battery cell with the fastest temperature rise in the semi-circular part is identified as the target lithium battery cell. The time it takes for the target lithium battery cell to reach the upper limit of its operating temperature is calculated as the cycle alternation time. Every cycle alternation time, the actual operating current of the lithium battery cells in the two semi-circular parts is exchanged and set, and the current output by the lithium battery cell is controlled by the battery pack to be equal to the actual operating current.
[0005] Preferably, the battery pack used in the special vehicle is obtained as follows: The battery pack integrates AC power, DC power, UPS, DC-DC conversion unit and inverter unit into one unit. It adopts an independent electrical circuit, outputs AC and DC power simultaneously, and has mechanical and electrical double interlocking functions. It replaces the UPS host with an AC power inverter and uses a DC / DC converter connected in parallel to the DC bus to replace the communication battery pack and charging equipment.
[0006] Preferably, obtaining the reference proportion of the area of the lithium battery cells exposed to the outside based on the spatial arrangement of the lithium battery cells includes the following steps: Obtain the top surface area, bottom surface area, and side surface area of the lithium battery block. Add up the top surface area, bottom surface area, and side surface area to get the total area. When there is a lithium battery block on the upper surface of the lithium battery block, the upper coefficient is 0; otherwise, the upper coefficient is 1. When a lithium battery block exists on the lower surface of the lithium battery block, the lower coefficient is 0; otherwise, the lower coefficient is 1. The number of lithium battery blocks on the side of the lithium battery block is counted and used as a characteristic value. The result of dividing the characteristic value by 8 is subtracted from 1 and the absolute value is taken to obtain the side coefficient. The exposed area of the lithium battery pack is calculated using a comprehensive formula. The reference ratio is obtained by dividing the exposed area of the lithium battery pack by the total area; The comprehensive formula is as follows: , Where A is the exposed area of the lithium battery block, B is the upper surface area, C is the lower surface area, D is the side area, b is the upper coefficient, c is the lower coefficient, and d is the side coefficient.
[0007] Preferably, establishing the relationship model between the operating current and operating temperature of the lithium battery pack includes the following steps: Based on historical data, the operating temperature range of the lithium battery pack is obtained, and the operating temperature range is divided into equal intervals to obtain at least one temperature point. The heat dissipation rate of the lithium battery cell is obtained when the temperature of the lithium battery cell is equal to the temperature point and there is no obstruction. By pairing and fitting the temperature point with the heat loss rate, a heat loss fitting function is obtained, where the temperature point is the independent variable and the heat loss rate is the dependent variable. The heat generation function of electric current is obtained. Where I is the operating current, R is the resistance of the lithium battery pack, and t is the energizing time; Taking the derivative of the heat generation function with respect to time, we obtain the function of the rate of heat increase. ; The heat increase rate function and the heat dissipation fitting function are used as the relationship model between the operating current and operating temperature of the lithium battery cell.
[0008] Preferably, obtaining the upper limit of the operating current of the lithium battery pack based on the fitted model and spatial arrangement includes the following steps: Multiply the reference ratio of the lithium battery pack by the loss fitting function to obtain the loss fitting correction function; The equation formed by the function of the rate of increase in heat being equal to the loss fitting correction function is taken as the characteristic equation; Substituting the upper limit of the operating temperature into the characteristic equation and solving it inversely yields the value of the current, which is used as the upper limit of the operating current of the lithium battery cell.
[0009] Preferably, dividing the battery pack into a central portion and two semi-circular portions includes the following steps: A feature box is drawn on the upper surface of the battery pack. The feature box and the upper surface of the battery pack are similar in that the center of the similarity is the center of the upper surface of the battery pack. The portion where the vertical projection of the feature box intersects with the battery pack is taken as the feature part; The feature portion containing exactly one-third of the lithium battery block is taken as the central part, and the part of the battery pack other than the central part is taken as the ring part; The plane perpendicular to the front and rear surfaces of the battery pack and passing through the center of the upper surface of the battery pack is taken as the feature plane; The feature plane divides the annular portion into two semi-annular portions.
[0010] Preferably, the actual operating current of the lithium battery cell in the semi-annular portion and the actual operating current of the lithium battery cell in the central portion include the following steps: The two semi-circular parts are designated as the first semi-circular part and the second semi-circular part, respectively. The upper limit of the operating current of the lithium battery block is set to the actual operating current of the lithium battery block in the central part. The upper limit of the operating current of the lithium battery block is set to the actual operating current of the lithium battery block in the second semi-circular part. The difference between the total current usage and the comprehensive current limit is used to obtain the current to be allocated; The upper limit of the working current of the lithium battery cells in the first semi-annular section is accumulated to obtain a partial current threshold. The distribution coefficient of the lithium battery cells in the first semi-circular section is obtained by dividing the upper limit of the working current of the lithium battery cells in the first semi-circular section by the partial current threshold. The current to be allocated is multiplied by the allocation coefficient of the lithium battery block in the first semi-circular part to obtain the current allocation amount of the lithium battery block in the first semi-circular part. The actual operating current of the lithium battery pack in the first semi-circular section is obtained by superimposing the current distribution of the lithium battery pack in the first semi-circular section with the upper limit of the operating current.
[0011] Preferably, identifying the lithium battery block with the fastest temperature rise in the semi-annular portion as the target lithium battery block includes the following steps: Obtain the real-time temperature of the battery pack at the current moment, use the real-time temperature and the upper limit of the operating temperature to form a feature interval, divide the feature interval at equal intervals, and obtain at least one feature point; Substituting the feature points into the heat loss fitting correction function yields the actual rate of heat loss. Substituting the actual operating current of the lithium battery block in the semi-circular section into the heat increase rate function, we obtain the actual heat increase rate. The effective rate of heat increase is obtained by subtracting the actual rate of heat increase from the actual rate of heat loss. The average rate of effective heat increase at at least one characteristic point is taken as the temperature rise index of the lithium battery block, and the lithium battery block with the largest temperature rise index is taken as the target lithium battery block.
[0012] Preferably, the calculation of the time it takes for the target lithium battery block to reach its upper operating temperature limit, as the cycle alternation time, includes the following steps: Obtain the specific heat capacity and mass of the target lithium battery block, and use the specific heat capacity formula to calculate the heating energy of adjacent feature points; Substituting the average value of adjacent feature points into the heat loss fitting correction function yields the target heat loss rate. Substituting the actual operating current of the target lithium battery block into the heat increase rate function yields the target heat increase rate. The effective target rate of heat gain is obtained by subtracting the target rate of heat loss from the target rate of heat gain. The characteristic time is obtained by dividing the heating energy of adjacent feature points by the effective target velocity of the target lithium battery block. The feature times of all adjacent feature points are superimposed to obtain the cyclical alternation time; The formula for specific heat capacity is as follows: , Where Q is the heating energy of adjacent feature points, T is the difference between adjacent feature points, e is the specific heat capacity of the target lithium battery block, and m is the mass of the target lithium battery block.
[0013] Preferably, the step of exchanging the actual operating current of the lithium battery cells in the two semi-annular sections at each interval of the cycle includes the following steps: The intersection of the two semi-circular parts is taken as the plane of symmetry. The lithium battery blocks in the two semi-circular parts are established in a corresponding relationship, and the corresponding lithium battery blocks are symmetrically distributed about the plane of symmetry. At each cycle interval, the actual operating current of the corresponding lithium battery cell is switched and set.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: By establishing a fitting model, obtaining the upper limit of the working current of the lithium battery pack, forming a central part and two semi-circular parts, and implementing alternating cyclic management, different current settings can be made according to different total current usage. When the total current usage exceeds the sum of the upper limits of the working current of all lithium battery packs, the current output can still be completed through alternating cyclic operation, while ensuring that the temperature is below the upper limit of the working temperature, thus ensuring that the lithium battery pack will not be damaged. When the total current usage does not exceed the sum of the upper limits of the working current of all lithium battery packs, the heat dissipation of different lithium battery packs can be analyzed according to the spatial arrangement of the lithium battery packs, and then the actual working current of different lithium battery packs can be set accordingly. This ensures that the lithium battery packs will not overheat and be damaged when operating according to the actual working current, thus enabling uninterrupted power supply. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the uninterruptible power supply system based on vehicle-mounted intelligent power management according to the present invention. Figure 2 This is a schematic diagram illustrating the process of obtaining a reference ratio of the area of lithium battery blocks exposed to the outside based on the spatial arrangement of lithium battery blocks according to the present invention. Figure 3 This is a schematic diagram of the process for establishing the relationship model between the operating current and operating temperature of a lithium battery cell according to the present invention. Figure 4 This is a schematic diagram illustrating the process of obtaining the upper limit of the operating current of a lithium battery block based on a fitting model and spatial arrangement position according to the present invention. Figure 5This is a schematic diagram of the process of dividing the battery pack into a central part and two semi-circular parts according to the present invention. Figure 6 This is a schematic diagram showing the actual operating current of the lithium battery block in the semi-annular portion and the actual operating current of the lithium battery block in the central portion of the present invention. Figure 7 The flowchart of the present invention is shown to identify the lithium battery block with the fastest temperature rise in the semi-annular part as the target lithium battery block. Figure 8 This is a flowchart illustrating the process of calculating the time it takes for the target lithium battery block to reach its upper operating temperature limit, as described in this invention; Figure 9 This is a schematic diagram illustrating the process of exchanging the actual operating current of the lithium battery cells in the two semi-circular sections at each interval of the present invention. Detailed Implementation
[0016] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.
[0017] Reference Figure 1 As shown, the uninterruptible power supply system based on vehicle intelligent power management includes: The parameter acquisition module acquires the battery pack used in the special vehicle, acquires the spatial arrangement of at least one lithium battery cell in the battery pack, and acquires a reference ratio of the area of the lithium battery cell exposed to the outside based on the spatial arrangement of the lithium battery cell. The data acquisition module obtains the upper limit of the operating temperature of the lithium battery pack and the total current usage of all lithium battery packs based on historical usage data. The model building module establishes a model of the relationship between the working current and the working temperature of the lithium battery pack, denoted as the fitting model. The data calculation module obtains the upper limit of the working current of the lithium battery block based on the fitting model and spatial arrangement position. It accumulates at least one upper limit of the working current to obtain the comprehensive upper limit of the current. The total current usage is divided by the comprehensive upper limit of the current to obtain the effective parameters. The battery control module, when the effective parameter does not exceed 1, multiplies the upper limit of the lithium battery cell's operating current by the effective parameter to obtain the actual operating current of the lithium battery cell. When the effective parameter exceeds 1, the battery pack is divided into a central part and two semi-circular parts, forming the actual operating current of the lithium battery cells in the semi-circular parts and the actual operating current of the lithium battery cells in the central part. The lithium battery cell with the fastest temperature rise in the semi-circular part is identified as the target lithium battery cell. The time it takes for the target lithium battery cell to reach the upper limit of its operating temperature is calculated as the cycle alternation time. Every cycle alternation time, the actual operating current of the lithium battery cells in the two semi-circular parts is exchanged and set, and the current output by the lithium battery cell is controlled by the battery pack to be equal to the actual operating current.
[0018] The heat generated by a lithium battery pack is mainly determined by its output current. Since there are many lithium battery packs in the pack, they will be stacked. The exposure of lithium battery packs to the air varies in different locations, resulting in different heat dissipation conditions and therefore different maximum operating currents. Therefore, different current settings can be made according to their characteristics to ensure that the temperature does not get too high. For lithium battery packs, the most important factor is whether the total current usage of all lithium battery packs exceeds the overall current limit. When it does not exceed the limit, the requirement can be met through conventional current distribution. However, once it does exceed the limit, no matter how the current is distributed, it will not be possible to achieve the desired result. In this solution, the battery pack is divided into a central section and two semi-circular sections. By setting the current of one semi-circular section higher and the current of the other semi-circular section and the central section lower, the temperature gradually increases and will not immediately reach the upper limit of the operating temperature. Therefore, time space is left for adjustment. When the temperature of the semi-circular section with the higher current setting reaches the upper limit of the operating temperature, the current of the two semi-circular sections is swapped. Since the semi-circular section with the higher current setting is the highest, when its temperature has not reached the upper limit of the operating temperature, the rest of the section has not reached the upper limit either. After the current settings are swapped, the temperature of the semi-circular section with the higher current setting will decrease. Since it is located on the outside, and such devices usually have ventilation and heat dissipation devices around them, the temperature can drop relatively quickly. The steps to achieve this effect will be explained in detail later in this solution.
[0019] The specific details of the battery pack used in the special-purpose vehicle are as follows: The battery pack integrates AC power, DC power, UPS, DC-DC conversion unit and inverter unit into one unit. It adopts an independent electrical circuit, outputs AC and DC power simultaneously, and has mechanical and electrical double interlocking functions. It replaces the UPS host with an AC power inverter and uses a DC / DC converter connected in parallel to the DC bus to replace the communication battery pack and charging equipment.
[0020] Reference Figure 2 As shown, obtaining a reference proportion of the area of lithium battery cells exposed to the outside, based on the spatial arrangement of the lithium battery cells, includes the following steps: Obtain the top surface area, bottom surface area, and side surface area of the lithium battery block. Add up the top surface area, bottom surface area, and side surface area to get the total area. When there is a lithium battery block on the upper surface of the lithium battery block, the upper coefficient is 0; otherwise, the upper coefficient is 1. When a lithium battery block exists on the lower surface of the lithium battery block, the lower coefficient is 0; otherwise, the lower coefficient is 1. The number of lithium battery blocks on the side of the lithium battery block is counted and used as a characteristic value. The result of dividing the characteristic value by 8 is subtracted from 1 and the absolute value is taken to obtain the side coefficient. The exposed area of the lithium battery pack is calculated using a comprehensive formula. The reference ratio is obtained by dividing the exposed area of the lithium battery pack by the total area; The comprehensive formula is as follows: , Where A is the exposed area of the lithium battery block, B is the upper surface area, C is the lower surface area, D is the side area, b is the upper coefficient, c is the lower coefficient, and d is the side coefficient.
[0021] The situation regarding the top and bottom surfaces of the lithium battery pack is easy to understand; if there is obstruction, these areas cannot dissipate heat. For the sides of the lithium battery pack, consider inserting all lithium battery packs into a 3x3 grid. The lithium battery pack in the center of the grid is surrounded by eight other lithium battery packs within the grid. Each of the eight lithium battery packs can be considered to have a similar level of obstruction to heat dissipation. Heat dissipation occurs through the unobstructed portions. Dividing the eigenvalue by 8 describes the obstructed portion, while the side coefficient obtained by subtracting from 1 and taking the absolute value describes the exposed portion. The subsequent fitting model describes the situation without obstruction, i.e., complete exposure. Therefore, its heat dissipation differs from that of different exposed areas, and this difference needs to be characterized to utilize the results of the fitting model.
[0022] Reference Figure 3 As shown, establishing a model for the relationship between the operating current and operating temperature of a lithium battery pack includes the following steps: Based on historical data, the operating temperature range of the lithium battery pack is obtained, and the operating temperature range is divided into equal intervals to obtain at least one temperature point. The heat dissipation rate of the lithium battery cell is obtained when the temperature of the lithium battery cell is equal to the temperature point and there is no obstruction. By pairing and fitting the temperature point with the heat loss rate, a heat loss fitting function is obtained, where the temperature point is the independent variable and the heat loss rate is the dependent variable. The heat generation function of electric current is obtained. Where I is the operating current, R is the resistance of the lithium battery pack, and t is the energizing time; Taking the derivative of the heat generation function with respect to time, we obtain the function of the rate of heat increase. ; The heat increase rate function and the heat dissipation fitting function are used as the relationship model between the operating current and operating temperature of the lithium battery cell.
[0023] The temperature of a lithium battery pack is mainly related to its operating current and its heat dissipation rate. The operating current generates heat, which leads to an increase in temperature. The higher the temperature, the faster the heat dissipation. Eventually, the rate of heat dissipation and the rate of heat generation reach equilibrium, thus yielding its steady-state temperature. Therefore, we construct a heat increase rate function and a heat dissipation fitting function to calculate subsequent related data. For example, based on the upper limit of the lithium battery pack's operating temperature, we can estimate the upper limit of the lithium battery pack's operating current.
[0024] Reference Figure 4 As shown, based on the fitted model and spatial arrangement, the upper limit of the operating current of the lithium battery pack is obtained through the following steps: Multiply the reference ratio of the lithium battery pack by the loss fitting function to obtain the loss fitting correction function; The equation formed by the function of the rate of increase in heat being equal to the loss fitting correction function is taken as the characteristic equation; Substituting the upper limit of the operating temperature into the characteristic equation and solving it inversely yields the value of the current, which is used as the upper limit of the operating current of the lithium battery cell.
[0025] Since the heat dissipation of lithium battery cells varies at different locations, the amount of heat generated is determined by the current. However, the heat dissipation will vary due to different barriers. Since a dissipation fitting function has been established, heat dissipation can be predicted. However, the different barriers also need to be considered. Therefore, the dissipation fitting function is multiplied by the reference ratio of the lithium battery cell to obtain the dissipation fitting correction function for subsequent calculations. Since the upper limit of the operating current of the lithium battery cell also varies, it is necessary to calculate the upper limit of the operating current of the lithium battery cell. Thus, as long as the operating current of the lithium battery cell does not exceed the upper limit of the operating current of the lithium battery cell, it can be ensured that it will not overheat.
[0026] Reference Figure 5 As shown, dividing the battery pack into a central section and two semi-circular sections includes the following steps: A feature box is drawn on the upper surface of the battery pack. The feature box and the upper surface of the battery pack are similar in that the center of the similarity is the center of the upper surface of the battery pack. The portion where the vertical projection of the feature box intersects with the battery pack is taken as the feature part; The feature portion containing exactly one-third of the lithium battery block is taken as the central part, and the part of the battery pack other than the central part is taken as the ring part; The plane perpendicular to the front and rear surfaces of the battery pack and passing through the center of the upper surface of the battery pack is taken as the feature plane; The feature plane divides the annular portion into two semi-annular portions.
[0027] By using two semi-circular sections, high current can be switched, and when the temperature reaches the upper limit of the lithium battery cell's operating temperature, the current is switched to prevent overheating.
[0028] Reference Figure 6 As shown, the actual operating current of the lithium battery cells in the semi-annular portion and the actual operating current of the lithium battery cells in the central portion include the following steps: The two semi-circular parts are designated as the first semi-circular part and the second semi-circular part, respectively. The upper limit of the operating current of the lithium battery block is set to the actual operating current of the lithium battery block in the central part. The upper limit of the operating current of the lithium battery block is set to the actual operating current of the lithium battery block in the second semi-circular part. The difference between the total current usage and the comprehensive current limit is used to obtain the current to be allocated; The upper limit of the working current of the lithium battery cells in the first semi-annular section is accumulated to obtain a partial current threshold. The distribution coefficient of the lithium battery cells in the first semi-circular section is obtained by dividing the upper limit of the working current of the lithium battery cells in the first semi-circular section by the partial current threshold. The current to be allocated is multiplied by the allocation coefficient of the lithium battery block in the first semi-circular part to obtain the current allocation amount of the lithium battery block in the first semi-circular part. The actual operating current of the lithium battery pack in the first semi-circular section is obtained by superimposing the current distribution of the lithium battery pack in the first semi-circular section with the upper limit of the operating current.
[0029] When distributing the excess current, since the upper limit of the working current of the lithium battery blocks at different positions in the first semi-ring section is different, it is necessary to distribute the current according to their characteristics. This is more in line with their heat dissipation. First, the current is distributed in the first semi-ring section. Then, the currents of the first semi-ring section and the second semi-ring section are symmetrically swapped and repeated cyclically.
[0030] Reference Figure 7 As shown, the lithium battery block with the fastest temperature rise in the semi-annular portion is identified as the target lithium battery block, and the following steps are included: Obtain the real-time temperature of the battery pack at the current moment, use the real-time temperature and the upper limit of the operating temperature to form a feature interval, divide the feature interval at equal intervals, and obtain at least one feature point; Substituting the feature points into the heat loss fitting correction function yields the actual rate of heat loss. Substituting the actual operating current of the lithium battery block in the semi-circular section into the heat increase rate function, we obtain the actual heat increase rate. The effective rate of heat increase is obtained by subtracting the actual rate of heat increase from the actual rate of heat loss. The average rate of effective heat increase at at least one characteristic point is taken as the temperature rise index of the lithium battery block, and the lithium battery block with the largest temperature rise index is taken as the target lithium battery block.
[0031] When performing temperature control, it is not necessary to calculate for all lithium battery cells. It is only necessary to find the target lithium battery cell that heats up the fastest and process it. As long as the temperature of the target lithium battery cell is not too high, the other lithium battery cells will not overheat. This avoids excessive calculation.
[0032] Reference Figure 8 As shown, calculating the time it takes for the target lithium battery cell to reach its upper operating temperature limit, as the cycle time, includes the following steps: Obtain the specific heat capacity and mass of the target lithium battery block, and use the specific heat capacity formula to calculate the heating energy of adjacent feature points; Substituting the average value of adjacent feature points into the heat loss fitting correction function yields the target heat loss rate. Substituting the actual operating current of the target lithium battery block into the heat increase rate function yields the target heat increase rate. The effective target rate of heat gain is obtained by subtracting the target rate of heat loss from the target rate of heat gain. The characteristic time is obtained by dividing the heating energy of adjacent feature points by the effective target velocity of the target lithium battery block. The feature times of all adjacent feature points are superimposed to obtain the cyclical alternation time; The formula for specific heat capacity is as follows: , Where Q is the heating energy of adjacent feature points, T is the difference between adjacent feature points, e is the specific heat capacity of the target lithium battery block, and m is the mass of the target lithium battery block.
[0033] This requires calculating the time it takes for the target lithium battery block to reach its operating temperature limit, but this process is complex. In this solution, this effect is achieved through approximate calculation. By obtaining feature points, when the segmentation interval is small enough, adjacent feature points are very close. The smaller of the adjacent feature points is taken as the first feature point, and the larger of the adjacent feature points is taken as the second feature point. Therefore, it can be assumed that the rate at which the first feature point heats up to the second feature point is constant. Thus, the characteristic time from the first feature point to the second feature point can be calculated using the above method. The time for the target lithium battery block to reach its operating temperature limit is composed of all adjacent feature points. Therefore, the cycle alternation time can be approximated. Moreover, depending on the required accuracy, the distance between adjacent feature points can be reduced, i.e., the number of feature points can be increased.
[0034] Reference Figure 9 As shown, the actual operating current of the lithium battery cells in the two semi-circular sections is switched and set at each interval of the cycle, including the following steps: The intersection of the two semi-circular parts is taken as the plane of symmetry. The lithium battery blocks in the two semi-circular parts are established in a corresponding relationship, and the corresponding lithium battery blocks are symmetrically distributed about the plane of symmetry. At each cycle interval, the actual operating current of the corresponding lithium battery cell is switched and set.
[0035] Furthermore, this solution also proposes a storage medium on which a computer-readable program is stored, which, when invoked, executes the aforementioned uninterruptible power supply system based on vehicle intelligent power management.
[0036] It is understandable that the storage medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid-state drive (SSD).
[0037] In summary, the advantages of this invention are as follows: by establishing a fitting model, obtaining the upper limit of the working current of the lithium battery block, forming a central part and two semi-circular parts, and implementing alternating cyclic management, different current settings can be made according to different total current usage. This ensures that even when the total current usage exceeds the sum of the upper limits of the working current of all the lithium battery blocks, the current output can still be completed through alternating cyclic operation, while ensuring that the temperature remains below the upper limit of the working temperature, thus preventing damage to the lithium battery block. When the total current usage does not exceed the sum of the upper limits of the working current of all the lithium battery blocks, the heat dissipation of different lithium battery blocks can be analyzed based on their spatial arrangement, thereby determining the actual working current for each lithium battery block. This ensures that the lithium battery blocks will not overheat and be damaged when operating according to the actual working current.
[0038] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.
Claims
1. An uninterruptible power supply system based on vehicle-mounted intelligent power management, characterized in that, include: The parameter acquisition module acquires the battery pack used in the special vehicle, acquires the spatial arrangement of at least one lithium battery cell in the battery pack, and acquires a reference ratio of the area of the lithium battery cell exposed to the outside based on the spatial arrangement of the lithium battery cell. The data acquisition module obtains the upper limit of the operating temperature of the lithium battery pack and the total current usage of all lithium battery packs based on historical usage data. The model building module establishes a model of the relationship between the working current and the working temperature of the lithium battery pack, denoted as the fitting model. The data calculation module obtains the upper limit of the working current of the lithium battery block based on the fitting model and spatial arrangement position. It accumulates at least one upper limit of the working current to obtain the comprehensive upper limit of the current. The total current usage is divided by the comprehensive upper limit of the current to obtain the effective parameters. The battery control module, when the effective parameter does not exceed 1, multiplies the upper limit of the lithium battery cell's operating current by the effective parameter to obtain the actual operating current of the lithium battery cell. When the effective parameter exceeds 1, the battery pack is divided into a central part and two semi-circular parts, forming the actual operating current of the lithium battery cells in the semi-circular parts and the actual operating current of the lithium battery cells in the central part. The lithium battery cell with the fastest temperature rise in the semi-circular part is identified as the target lithium battery cell. The time it takes for the target lithium battery cell to reach the upper limit of its operating temperature is calculated as the cycle alternation time. Every cycle alternation time, the actual operating current of the lithium battery cells in the two semi-circular parts is exchanged and set, and the current output by the lithium battery cell is controlled by the battery pack to be equal to the actual operating current.
2. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 1, characterized in that, The specific details of the battery pack used in the special-purpose vehicle are as follows: The battery pack integrates AC power, DC power, UPS, DC-DC conversion unit and inverter unit into one unit. It adopts an independent electrical circuit, outputs AC and DC power simultaneously, and has mechanical and electrical double interlocking functions. It replaces the UPS host with an AC power inverter and uses a DC / DC converter connected in parallel to the DC bus to replace the communication battery pack and charging equipment.
3. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 2, characterized in that, The process of obtaining a reference proportion of the area of lithium battery cells exposed to the outside based on the spatial arrangement of the lithium battery cells includes the following steps: Obtain the top surface area, bottom surface area, and side surface area of the lithium battery block. Add up the top surface area, bottom surface area, and side surface area to get the total area. When there is a lithium battery block on the upper surface of the lithium battery block, the upper coefficient is 0; otherwise, the upper coefficient is 1. When a lithium battery block exists on the lower surface of the lithium battery block, the lower coefficient is 0; otherwise, the lower coefficient is 1. The number of lithium battery blocks on the side of the lithium battery block is counted and used as a characteristic value. The result of dividing the characteristic value by 8 is subtracted from 1 and the absolute value is taken to obtain the side coefficient. The exposed area of the lithium battery pack is calculated using a comprehensive formula. The reference ratio is obtained by dividing the exposed area of the lithium battery pack by the total area; The comprehensive formula is as follows: ， Where A is the exposed area of the lithium battery block, B is the upper surface area, C is the lower surface area, D is the side area, b is the upper coefficient, c is the lower coefficient, and d is the side coefficient.
4. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 3, characterized in that, The steps involved in establishing the relationship model between the operating current and operating temperature of the lithium battery pack are as follows: Based on historical data, the operating temperature range of the lithium battery pack is obtained, and the operating temperature range is divided into equal intervals to obtain at least one temperature point. The heat dissipation rate of the lithium battery cell is obtained when the temperature of the lithium battery cell is equal to the temperature point and there is no obstruction. By pairing and fitting the temperature point with the heat loss rate, a heat loss fitting function is obtained, where the temperature point is the independent variable and the heat loss rate is the dependent variable. The heat generation function of electric current is obtained. Where I is the operating current, R is the resistance of the lithium battery pack, and t is the energizing time; Taking the derivative of the heat generation function with respect to time, we obtain the function of the rate of heat increase. ; The heat increase rate function and the heat dissipation fitting function are used as the relationship model between the operating current and operating temperature of the lithium battery cell.
5. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 4, characterized in that, The process of obtaining the upper limit of the operating current of the lithium battery pack based on the fitted model and spatial arrangement includes the following steps: Multiply the reference ratio of the lithium battery pack by the loss fitting function to obtain the loss fitting correction function; The equation formed by the function of the rate of increase in heat being equal to the loss fitting correction function is taken as the characteristic equation; Substituting the upper limit of the operating temperature into the characteristic equation and solving it inversely yields the value of the current, which is used as the upper limit of the operating current of the lithium battery cell.
6. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 5, characterized in that, The process of dividing the battery pack into a central portion and two semi-circular portions includes the following steps: A feature box is drawn on the upper surface of the battery pack. The feature box and the upper surface of the battery pack are similar in that the center of the similarity is the center of the upper surface of the battery pack. The portion where the vertical projection of the feature box intersects with the battery pack is taken as the feature part; The feature portion containing exactly one-third of the lithium battery block is taken as the central part, and the part of the battery pack other than the central part is taken as the ring part; The plane perpendicular to the front and rear surfaces of the battery pack and passing through the center of the upper surface of the battery pack is taken as the feature plane; The feature plane divides the annular portion into two semi-annular portions.
7. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 6, characterized in that, The actual operating current of the lithium battery cell in the semi-annular portion and the actual operating current of the lithium battery cell in the central portion include the following steps: The two semi-circular parts are designated as the first semi-circular part and the second semi-circular part, respectively. The upper limit of the operating current of the lithium battery block is set to the actual operating current of the lithium battery block in the central part. The upper limit of the operating current of the lithium battery block is set to the actual operating current of the lithium battery block in the second semi-circular part. The difference between the total current usage and the comprehensive current limit is used to obtain the current to be allocated; The upper limit of the working current of the lithium battery cells in the first semi-annular section is accumulated to obtain a partial current threshold. The distribution coefficient of the lithium battery cells in the first semi-circular section is obtained by dividing the upper limit of the working current of the lithium battery cells in the first semi-circular section by the partial current threshold. The current to be allocated is multiplied by the allocation coefficient of the lithium battery block in the first semi-circular part to obtain the current allocation amount of the lithium battery block in the first semi-circular part. The actual operating current of the lithium battery pack in the first semi-circular section is obtained by superimposing the current distribution of the lithium battery pack in the first semi-circular section with the upper limit of the operating current.
8. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 7, characterized in that, The process of identifying the lithium battery block with the fastest temperature rise in the semi-annular portion as the target lithium battery block includes the following steps: Obtain the real-time temperature of the battery pack at the current moment, use the real-time temperature and the upper limit of the operating temperature to form a feature interval, divide the feature interval at equal intervals, and obtain at least one feature point; Substituting the feature points into the heat loss fitting correction function yields the actual rate of heat loss. Substituting the actual operating current of the lithium battery block in the semi-circular section into the heat increase rate function, we obtain the actual heat increase rate. The effective rate of heat increase is obtained by subtracting the actual rate of heat increase from the actual rate of heat loss. The average rate of effective heat increase at at least one characteristic point is taken as the temperature rise index of the lithium battery block, and the lithium battery block with the largest temperature rise index is taken as the target lithium battery block.
9. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 8, characterized in that, The calculation of the time it takes for the target lithium battery block to reach its upper operating temperature limit, as the cycle alternation time, includes the following steps: Obtain the specific heat capacity and mass of the target lithium battery block, and use the specific heat capacity formula to calculate the heating energy of adjacent feature points; Substituting the average value of adjacent feature points into the heat loss fitting correction function yields the target heat loss rate. Substituting the actual operating current of the target lithium battery block into the heat increase rate function yields the target heat increase rate. The effective target rate of heat gain is obtained by subtracting the target rate of heat loss from the target rate of heat gain. The characteristic time is obtained by dividing the heating energy of adjacent feature points by the effective target velocity of the target lithium battery block. The feature times of all adjacent feature points are superimposed to obtain the cyclical alternation time; The formula for specific heat capacity is as follows: ， Where Q is the heating energy of adjacent feature points, T is the difference between adjacent feature points, e is the specific heat capacity of the target lithium battery block, and m is the mass of the target lithium battery block.
10. The uninterruptible power supply system based on vehicle-mounted intelligent power management according to claim 9, characterized in that, The process of exchanging the actual operating current of the lithium battery cells in the two semi-circular sections at each interval includes the following steps: The intersection of the two semi-circular parts is taken as the plane of symmetry. The lithium battery blocks in the two semi-circular parts are established in a corresponding relationship, and the corresponding lithium battery blocks are symmetrically distributed about the plane of symmetry. At each cycle interval, the actual operating current of the corresponding lithium battery cell is switched and set.