A new energy engineering vehicle lithium battery pack heat dissipation assembly

Abstract

This invention discloses a heat dissipation component for lithium battery packs in new energy engineering vehicles, belonging to the field of lithium battery heat dissipation technology. The component includes a battery pack housing, a finned heat sink, an axial flow cooling fan, a coolant reservoir, and a liquid cooling plate, forming a closed-loop circuit. The coolant circuit output flow rate is adjusted by calculating the thermal admittance of the cold plate. The remaining heat dissipation potential energy is obtained based on the coupling relationship between the thermal admittance of the cold plate and the heat transfer capacity of the air-cooled side, and the fan speed is adjusted accordingly. Then, the effective value of the cell heat flux density vector is calculated based on the fusion relationship between the remaining heat dissipation potential energy and the root mean square relationship of the heat generation distribution of each row of cells, dynamically allocating the flow rate ratio of each channel of the liquid cooling plate. This invention can accurately sense changes in the heat dissipation system capacity and differences in the heat generation distribution of the cells, achieving proactive matching and adjustment, improving heat dissipation efficiency and temperature uniformity, reducing energy consumption, and extending battery life.

Description

Technical Field

[0001] This invention relates to the field of lithium battery heat dissipation technology, and in particular to a heat dissipation component for lithium battery packs in new energy engineering vehicles. Background Technology

[0002] Due to the unique operating environments of new energy engineering vehicles, they frequently face conditions such as high-current charging and discharging, drastic load fluctuations, and large changes in ambient temperature. The cooling system of the lithium battery pack directly determines the battery's safety, cycle life, and operational reliability. Currently, most industry-standard lithium battery cooling control solutions are based on adjusting threshold parameters directly collected, such as cell temperature and coolant temperature. Typically, a fixed temperature point is set; when the temperature exceeds the threshold, the pump and fan speeds are increased, and when it falls below the threshold, the speeds are decreased. Some solutions also incorporate sensors for flow and pressure to provide simple fault alarms.

[0003] The design logic of this type of solution only passively responds to temperature results, making it difficult to perceive changes in the cooling system's own capabilities, the matching relationship between heat generation and heat dissipation, and the differences in heat distribution within the battery cell. As a result, it has gradually become unsuitable for the high-load and highly fluctuating usage requirements of engineering vehicles. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing technology has the following drawbacks: distorted heat exchange capacity assessment, delayed fault warning, mismatch of series heat dissipation system capacity, serious energy waste, lack of heat generation distribution identification and poor temperature uniformity. To this end, we propose a heat dissipation component for lithium battery packs of new energy engineering vehicles.

[0005] The main technical solution is: a heat dissipation component for lithium battery packs in new energy engineering vehicles, including:

[0006] The battery pack housing contains two rows of lithium battery cells arranged side-by-side inside. A liquid cooling plate is installed between the two rows of lithium battery cells. Coolant passage pipes are distributed on the upper and lower sides of each lithium battery cell. A finned heat sink is fixedly installed on the outer side of the battery pack housing. An axial flow cooling fan is mounted on the finned heat sink. A coolant storage tank is installed below the finned heat sink. The coolant pipe interface is sequentially connected to the coolant passage pipes, the liquid cooling plate, the finned heat sink, and the coolant storage tank to form a closed loop.

[0007] Based on the matching relationship between the actual heat transfer flux of the liquid cooling plate on the liquid cooling side and the core liquid driving potential difference, the thermal admittance of the cold plate is calculated, and the output flow rate of the coolant circuit is adjusted with the thermal admittance of the cold plate as a reference.

[0008] Based on the coupling relationship between the thermal conductivity and admittance of the cold plate and the heat transfer capacity of the air-cooled side of the finned radiator and the heat transfer potential difference of the liquid fins, the remaining heat dissipation potential energy is calculated, and the output speed of the axial cooling fan is adjusted with the remaining heat dissipation potential energy as a reference.

[0009] Based on the root mean square fusion relationship between the remaining heat dissipation potential energy and the heat generation distribution of each column of lithium battery cells, the effective value of the cell heat flux density vector is calculated. With the effective value of the cell heat flux density vector as a reference, the flow rate ratio of each channel of the liquid cooling plate is dynamically allocated.

[0010] Preferably, the process of obtaining the thermal admittance of the cold plate includes:

[0011] The coolant mass flow rate, coolant specific heat capacity at constant pressure, first temperature difference between entering and exiting the liquid cooling plate, average cell temperature and average coolant temperature of the lithium battery cell are obtained.

[0012] Based on the product of coolant mass flow rate, coolant specific heat capacity at constant pressure and first temperature difference, the actual heat transfer flux on the liquid cooling side is obtained. The actual heat transfer flux on the liquid cooling side characterizes the total heat carried away by the coolant from the cell surface per unit time.

[0013] Based on the second temperature difference between the average temperature of the battery cell and the average temperature of the coolant, the core-liquid driving potential difference is obtained, which characterizes the power margin for heat transfer from the battery cell to the coolant.

[0014] The ratio of the actual heat transfer flux on the liquid-cooled side to the core liquid driving potential difference is denoted as the thermal admittance of the cold plate. The thermal admittance of the cold plate characterizes the effective heat transfer capacity of the liquid-cooled plate under a unit temperature difference.

[0015] Preferably, the adjustment process of the coolant circuit output flow rate with reference to the thermal admittance of the cold plate includes:

[0016] Obtain the preset rated health admittance value;

[0017] When the thermal conductivity of the cold plate is lower than 80% of the rated healthy admittance, it is determined that the flow is insufficient. The speed of the coolant pump is increased according to the proportion of the health gap, but not exceeding the rated speed of the pump.

[0018] When the thermal conductivity of the cold plate is higher than 120% of the rated healthy admittance, it is determined to be an excess flow. The coolant pump speed is reduced according to the health redundancy ratio, and the minimum speed is not lower than the minimum stable speed of the pump.

[0019] When the thermal conductivity admittance of the cold plate is lower than 50% of the rated healthy admittance value for three consecutive control cycles, it is determined to be a liquid cooling circuit fault, triggering a first-level alarm, increasing the axial cooling fan to full speed, and limiting the discharge power of the lithium battery cell to 60% of the rated value.

[0020] Preferably, the process of obtaining the remaining heat dissipation potential energy includes:

[0021] The convective heat transfer coefficient of the finned radiator surface, the effective heat transfer area of ​​the fins, the third temperature difference between the average temperature of the finned surface and the ambient temperature, and the coolant outlet temperature are obtained.

[0022] Based on the product of the convective heat transfer coefficient of the fin surface, the effective heat transfer area of ​​the fin and the third temperature difference, the theoretical maximum heat dissipation of the air-cooled side is obtained. The theoretical maximum heat dissipation of the air-cooled side represents the upper limit of the heat dissipation capacity of the finned heat sink at the current axial flow cooling fan speed.

[0023] The fourth temperature difference between the coolant outlet temperature and the average surface temperature of the fins is denoted as the liquid fin heat transfer potential difference, which represents the power margin for heat transfer from the coolant to the fins.

[0024] The ratio of the theoretical maximum heat dissipation of the air-cooled side to the heat transfer potential difference of the liquid fins is denoted as the heat transfer capacity per unit temperature difference of the air-cooled side. The product of the thermal admittance of the cold plate and the heat transfer capacity per unit temperature difference of the air-cooled side is denoted as the residual heat dissipation potential energy. The residual heat dissipation potential energy characterizes the maximum continuous heat dissipation power that the liquid-air-cooled series system can stably bear.

[0025] Preferably, the process of obtaining the convective heat transfer coefficient of the fin surface includes:

[0026] A calibration table of the axial cooling fan speed and convective heat transfer coefficient is pre-stored, and the calibration table is calibrated on a test bench through wind tunnel testing;

[0027] The current rotational speed of the axial cooling fan is collected in real time, and the corresponding convective heat transfer coefficient of the fin surface is obtained by looking up a table.

[0028] Preferably, the process of adjusting the output speed of the axial cooling fan with reference to the remaining heat dissipation potential energy includes:

[0029] When the remaining heat dissipation potential energy is lower than 80% of the actual heat exchange flux on the current liquid cooling side, it is determined that the air cooling capacity is insufficient, and the fan speed is increased proportionally to the heat dissipation margin gap, but not exceeding the rated fan speed.

[0030] When the remaining heat dissipation potential energy is higher than 120% of the actual heat exchange flux on the current liquid cooling side, it is determined that the air cooling redundancy is excessive, and the fan speed is reduced according to the proportion of the heat dissipation redundancy, with a minimum not lower than the minimum stable fan speed.

[0031] When the remaining heat dissipation potential energy increases by less than 2% with the increase of fan speed, it is determined that the air cooling is saturated, the speed of the axial cooling fan is locked, and the power limit threshold of the lithium battery cell is triggered.

[0032] Preferably, the process of obtaining the effective value of the cell heat flux density vector includes:

[0033] The remaining heat dissipation potential energy, the effective heat exchange area of ​​the liquid cooling plate in contact with the lithium battery cell, the cell heat flux density of each column of lithium battery cells, and the angle between the cell heat flux direction and the normal of the liquid cooling plate are obtained.

[0034] The ratio of the remaining heat dissipation potential energy to the effective heat exchange area is denoted as the allowable heat flow threshold per unit area, which represents the maximum heat flow limit that the liquid cooling plate can bear per unit contact area.

[0035] The product of the cell heat flux density of each row of cells and the cosine of the corresponding angle is denoted as the single-row effective heat flux, which represents the effective heat flux density that can be transferred to the liquid cooling plate from the heat generated by the cells in that row.

[0036] The root mean square value of the cell heat flux is obtained by taking the square root of the average of the squares of all effective heat fluxes in a single column. The root mean square value of the cell heat flux represents the equivalent uniform intensity of heat generation in multiple columns of cells and amplifies the risk weight of local high heat flux.

[0037] The product of the permissible heat flux threshold per unit area and the root mean square value of the cell heat flux is denoted as the effective value of the cell heat flux density vector. The effective value of the cell heat flux density vector represents the effective heat load of the cell that matches the current heat dissipation capacity.

[0038] Preferably, the process of obtaining the cell heat flux density includes:

[0039] The charging and discharging current of the lithium battery cells is collected in real time, and the current DC internal resistance of each column of cells is obtained by querying.

[0040] The cell heat flux density of a given cell is obtained by dividing the product of the DC internal resistance of each cell and the square of the current by the contact area between that cell and the liquid cooling plate.

[0041] Preferably, the process of dynamically allocating the flow rate ratio of each channel using the effective value of the cell heat flux density vector as a reference includes:

[0042] Based on the proportion of effective heat flow in each row of cells, the flow rate of the corresponding side channel of the liquid cooling plate is allocated accordingly.

[0043] When the temperature difference between the two rows of lithium battery cells exceeds 3°C, an additional 5%-10% flow rate is allocated to the flow channel of the row with the higher temperature until the temperature difference drops back to within 3°C.

[0044] When the effective value of the cell heat flux density vector exceeds the safety threshold corresponding to the remaining heat dissipation potential energy, the discharge power of the high heat flux column is limited first. If the safety requirements are still not met, the power limit of the entire group is then executed.

[0045] The technical effects and advantages of this invention are as follows:

[0046] In this invention, by collecting parameters such as coolant flow rate, inlet and outlet temperatures, and battery cell temperature, the total heat actually carried away by the coolant per unit time is first calculated. Then, this heat is compared with the average driving temperature difference between the battery cell and the coolant to obtain the thermal admittance of the liquid cooling plate, which is only related to the performance of the liquid cooling plate itself. This value is not affected by the current temperature difference or heat generation power, and directly reflects the heat exchange capacity of the liquid cooling plate under a unit driving temperature difference. When this characteristic value drops significantly in a short period of time, it can directly indicate a blockage or leakage fault in the flow channel, thereby improving the speed of triggering early warning. At the same time, the heat exchange saturation point of the liquid cooling plate can be identified by the trend of this characteristic value, avoiding the need for the liquid cooling pump to increase its speed unnecessarily and reducing pump energy consumption.

[0047] In this invention, based on the thermal conductivity and admittance of the cold plate, and combined with parameters such as the fin heat transfer coefficient, the temperature difference between the fins and the environment, and the temperature difference between the coolant and the fins, the heat transfer capacity per unit temperature difference on the fin side is calculated. The capacity characteristics of the two components are then normalized and fused to obtain the remaining heat dissipation potential energy. This value directly reflects the maximum heat dissipation power that the current liquid-cooled and air-cooled series system can stably handle, accurately identifying the heat dissipation bottleneck. Furthermore, when this characteristic value is higher than the actual heat load, the fan speed is reduced as needed; when it is lower than the actual heat load, the fan speed is increased as needed. Compared to existing temperature threshold control modes, this reduces the average energy consumption of the fan. Simultaneously, it allows for the prediction of heat dissipation margin before engineering vehicles climb hills or discharge with high current, enabling advance adjustment of the heat dissipation strategy and preventing cell temperature overshoot.

[0048] In this invention, the heat generation intensity of each row of cells is calculated by combining parameters such as current and internal resistance. The effective heat flow transferred to the liquid cooling plate is calculated by adjusting the angle of the heat flow direction. Then, the effective value of the cell heat flux density vector is obtained using the root mean square statistical method. This amplifies the influence of local high heat flux and avoids the risk of local overheating being masked by the average temperature of the entire group. In addition, based on the effective value of the cell heat flux density vector, the flow rate of the left and right channels of the liquid cooling plate is dynamically allocated according to the proportion of effective heat flow in a single row. This allows for the control of the temperature difference between multiple rows of cells, improving cell consistency and extending cycle life. Attached Figure Description

[0049] Figure 1 This is a front view of the overall structure of the heat dissipation component for lithium battery packs in new energy engineering vehicles according to the present invention;

[0050] Figure 2 For the present invention Figure 1 Enlarged schematic diagram of the structure at point A;

[0051] Figure 3 This is a top-view internal structural distribution diagram of the heat dissipation component for the lithium battery pack of the new energy engineering vehicle according to the present invention;

[0052] Figure 4 This is a side-view and internal view structural distribution diagram of the heat dissipation component for lithium battery packs in new energy engineering vehicles according to the present invention;

[0053] Figure 5 For the present invention Figure 4 Enlarged schematic diagram of the structure at point A1;

[0054] Figure 6 This is a schematic diagram of the entire process control logic for heat dissipation of the lithium battery pack for new energy engineering vehicles according to the present invention.

[0055] In the diagram: 1-Battery pack casing, 2-Finned heat sink, 3-Axial flow cooling fan, 4-Coolant reservoir, 5-Lithium battery cell, 6-Liquid cooling plate, 7-Coolant pipe interface, 8-Coolant passage pipe. Detailed Implementation

[0056] The present invention will now be described in further detail with reference to the accompanying drawings and preferred embodiments. This embodiment provides a heat dissipation component for lithium battery packs in new energy engineering vehicles. The overall concept is as follows: by constructing a three-layer progressive characteristic parameter system of liquid cooling plate thermal conductivity admittance, remaining heat dissipation potential energy, and effective value of cell heat flux density vector, the system can accurately sense changes in the heat dissipation system's own capacity and differences in cell heat distribution, thereby achieving active decoupling and matching of liquid cooling flow rate and air cooling speed, as well as dynamic on-demand allocation of flow rate inside the liquid cooling plate. This minimizes auxiliary energy consumption while ensuring heat dissipation efficiency and cell temperature uniformity.

[0057] The application scenarios targeted by this heat dissipation component are: primarily used in new energy engineering vehicles, especially in the thermal management systems of lithium battery packs that face long-term high-current charging and discharging, drastic load fluctuations, and large changes in ambient temperature. It should be understood that the core control logic of this invention does not depend on a specific hardware structure, but the hardware components described below provide the physical basis for its implementation.

[0058] In one exemplary embodiment, the control logic of the heat dissipation component can be configured as an intelligent heat dissipation control module embedded in a battery management system (BMS). This module collects temperature sensor signals in real time from the inlet and outlet of the liquid cooling plate 6, the surface of the finned heat sink 2, the environment, and each row of lithium battery cells 5. It also acquires the speed feedback of the coolant pump and the axial cooling fan 3, as well as the charging and discharging current and internal resistance data of the battery cells. Based on these inputs, the control module calculates and outputs in real time the speed commands of the coolant pump, the axial cooling fan 3, and the opening commands of the flow distribution valves inside the liquid cooling plate 6.

[0059] Example 1, as Figures 1-6 As shown, this embodiment of the invention provides a heat dissipation component for lithium battery packs in new energy engineering vehicles, comprising:

[0060] The battery pack housing 1 has two rows of lithium battery cells 5 installed side by side inside. A liquid cooling plate 6 is installed between the two rows of lithium battery cells 5. Coolant passage pipes 8 are installed on the upper and lower sides of the lithium battery cells 5. A finned heat sink 2 is fixedly installed on the outside of the battery pack housing 1. An axial flow cooling fan 3 is mounted on the finned heat sink 2. A coolant storage tank 4 is installed below the finned heat sink 2. The coolant pipe interface 7 is connected to the coolant passage pipes 8, the liquid cooling plate 6, the finned heat sink 2 and the coolant storage tank 4 in sequence to form a closed loop.

[0061] Based on the matching relationship between the actual heat transfer flux of the liquid cooling plate 6 liquid cooling side and the core liquid driving potential difference, the thermal admittance of the cold plate is calculated, and the output flow rate of the coolant circuit is adjusted with the thermal admittance of the cold plate as a reference.

[0062] Based on the coupling relationship between the thermal conductivity and admittance of the cold plate and the heat exchange capacity of the air-cooled side of the finned heat sink 2 and the heat transfer potential difference of the liquid fins, the remaining heat dissipation potential energy is calculated, and the output speed of the axial cooling fan 3 is adjusted with reference to the remaining heat dissipation potential energy.

[0063] Based on the root mean square fusion relationship between the remaining heat dissipation potential energy and the heat generation distribution of each column of lithium battery cells 5, the effective value of the cell heat flux density vector is calculated. With the effective value of the cell heat flux density vector as a reference, the flow rate ratio of each channel of the liquid cooling plate 6 is dynamically allocated.

[0064] In the above embodiments, a three-layer progressive control architecture is constructed, from liquid cooling core capability to air cooling matching capability and then to cell heat generation distribution. Specifically: First, the interference of temperature difference is eliminated by the thermal conductivity admittance of the cold plate, directly quantifying the health status and heat exchange efficiency of the liquid cooling plate 6 itself, and adjusting the coolant flow rate accordingly to avoid meaningless idling of the pump; Second, the liquid cooling capability is coupled with the heat exchange capability per unit temperature difference of the air cooling side to obtain the remaining heat dissipation potential energy of the series system, thereby accurately identifying whether the heat dissipation bottleneck is on the liquid cooling side or the air cooling side, and realizing the on-demand adjustment of the speed of the axial cooling fan 3. Finally, considering that the heat generation of the two rows of cells may differ, the upper limit of the heat dissipation system capability and the local heat generation intensity of the cells are weighted by the effective value of the heat flux density vector, guiding the differentiated distribution of flow rate in the left and right channels of the liquid cooling plate 6.

[0065] Understandably, the coolant passage pipes 8 are distributed on the upper and lower sides of the battery cell, forming a three-sided surrounding heat exchange structure together with the middle liquid cooling plate 6. This structural design increases the contact area between the coolant and the battery cell. However, if only uniform flow control is used, the temperature uniformity of the middle liquid cooling plate 6 will be limited when the left and right rows of battery cells generate different amounts of heat due to aging differences or different arrangement positions. Therefore, independently controlling the internal flow channels of the liquid cooling plate 6 by partition is one of the key technical means to solve this problem in this embodiment.

[0066] Example 2, as Figure 1 , Figures 3-6 As shown, based on Example 1, this embodiment of the invention provides a process for obtaining the thermal conductivity admittance of a cold plate.

[0067] In the above embodiments, the process of obtaining the thermal admittance of the cold plate specifically involves: obtaining the coolant mass flow rate, the coolant specific heat capacity at constant pressure, the first temperature difference between the inlet and outlet of the liquid-cooled plate 6, and the average cell temperature and average coolant temperature of the lithium battery cell 5. Based on the product of the coolant mass flow rate, the coolant specific heat capacity at constant pressure, and the first temperature difference, the actual heat transfer flux on the liquid-cooled side is obtained, which characterizes the total heat carried away by the coolant from the cell surface per unit time. Based on the second temperature difference between the average cell temperature and the average coolant temperature, the core-liquid driving potential difference is obtained, which characterizes the power margin for heat transfer from the cell to the coolant. The ratio of the actual heat transfer flux on the liquid-cooled side to the core-liquid driving potential difference is denoted as the thermal admittance of the cold plate.

[0068] Therefore, the quantification method for the thermal conductivity admittance of cold plates is as follows: ;

[0069] In the formula: C ptc The real-time thermal admittance of the liquid-cooled plate 6 characterizes the maximum heat transfer capacity that the current liquid-cooled plate can withstand. cool c is the mass flow rate of the coolant. p,coolT is the specific heat capacity of the coolant at constant pressure. cool out T represents the coolant outlet temperature of liquid cooling plate 6. cool in T represents the coolant inlet temperature of liquid cooling plate 6. core avg T represents the average temperature of the battery cell. cool avg The average temperature of the coolant inside the liquid cooling plate 6.

[0070] When a fluid flows through a heat exchange component, the heat it absorbs or releases is equal to the change in the fluid's enthalpy. For a coolant flowing at constant pressure, the enthalpy change is determined solely by the temperature change; therefore, the heat exchange can be directly calculated by multiplying the flow rate, specific heat capacity, and temperature difference. This represents the total heat that the coolant can absorb for every 1 Kelvin increase in temperature (specific heat capacity is the heat required for a unit mass of fluid to rise by 1 K; multiplying this by the mass flow rate gives the total heat absorption capacity per unit time for a 1 Kelvin increase); then multiply by the temperature rise. Ultimately, we can obtain the total heat actually absorbed by the coolant per unit time, which is the actual heat exchange carried away from the battery cell by the liquid cooling plate.

[0071] Among them, the subtraction part This represents the temperature rise of the coolant after it flows through the liquid cooling plate, and is a direct macroscopic manifestation of the heat absorbed by the coolant from the battery cell. In other words, only when the outlet temperature is higher than the inlet temperature can it be said that the coolant has indeed carried away the heat from the battery cell; if this value is 0, it means that the liquid cooling plate has not exchanged heat at all.

[0072] At this point, the thermal conductivity and admittance C of the cold plate are... ptc It can eliminate temperature difference interference and quantify the heat transfer capacity per unit temperature difference. It is affected by two factors: the heat transfer capacity of the liquid cooling plate 6 itself, and the size of the temperature difference between the battery cell and the coolant. For example, with the same liquid cooling plate 6, when the battery cell is 10°C higher than the coolant, the heat transfer capacity might be 1000W; but if the battery cell is only 2°C higher than the coolant, even if the liquid cooling plate 6 itself is of good performance, the heat transfer capacity will only be 200W. In this case, it is difficult to judge the performance of the liquid cooling plate 6 based solely on the heat transfer capacity. The calculation by dividing the actual heat exchange by the average core-liquid temperature difference essentially eliminates the temperature difference-driven factor in the heat exchange. It's equivalent to normalizing all operating conditions to a standard scenario where the core-liquid temperature difference is 1K. The resulting value is the heat that the liquid coolant plate can transfer per unit temperature difference. This value is only related to the flow channel unobstructedness of the liquid coolant plate itself, the flow state of the coolant, and the performance of the thermally conductive material, and is unrelated to the actual size of the current temperature difference.

[0073] Coolant circuit output flow rate is based on the thermal admittance C of the cold plate. ptc The adjustment process for reference includes:

[0074] First, pre-store the rated healthy admittance value C of the liquid cooling plate. ptc,rated (Obtained through simulation and experimentation during the design phase, representing the admittance value of the liquid cooler plate operating in its most efficient range).

[0075] Real-time comparison of the currently calculated C ptc With C ptc,rated The ratio:

[0076] When C ptc <0.8×C ptc,rated This indicates insufficient flow rate; the liquid cooling plate has not reached its optimal heat exchange state. Increase the coolant pump speed proportionally; for every 10% increase in flow rate, adjust C accordingly. ptc It can increase by approximately 5%-8%;

[0077] When 0.8×C ptc,rated ≤C ptc ≤1.2×C ptc,rated This indicates that the liquid cooling plate is operating within its optimal range, maintaining the current pump speed unchanged.

[0078] When C ptc >0.8×C ptc,rated This indicates that the current flow rate is excessive. Reduce the coolant pump speed to reduce pump energy consumption while ensuring heat exchange capacity.

[0079] Example 3, as Figure 6 As shown, based on Example 2, this embodiment of the invention provides emergency handling measures for insufficient and excessive traffic:

[0080] 1. When C ptc <0.8×C ptc,rated When there is insufficient current traffic:

[0081] C was monitored for three consecutive control cycles (1 second per cycle). ptc Below C ptc,rated If the flow rate sensor and coolant temperature sensor malfunctions are ruled out, and the flow rate sensor and coolant temperature sensor malfunctions are ruled out, then the liquid cooling circuit can be considered abnormal.

[0082] If the coolant circuit pressure drops at the same time, it indicates that there is a leak at the coolant passage pipe 8 or the interface.

[0083] If the circuit pressure is normal, it indicates that the internal flow channels of the liquid cooling plate 6 are blocked by impurities in the coolant.

[0084] Handling measures:

[0085] Immediately report a Level 1 fault alarm to notify the driver of the abnormality in the liquid cooling system;

[0086] Automatically increase the axial cooling fan speed to full speed, activate the emergency air cooling mode, and use the external heatsink for forced air cooling assistance.

[0087] Limit the maximum discharge power of the battery cell to 60% of its rated value to reduce the heat generation rate;

[0088] If the highest temperature of the battery cell exceeds 55°C within the next 10 minutes, a level 2 alarm will be triggered, and it is recommended to stop the machine immediately for inspection and repair.

[0089] 2. When C ptc >0.8×C ptc,rated This indicates that there is currently excess traffic.

[0090] When the coolant pump flow rate is gradually increased, C under three consecutive flow rate gradients ptc If the increase is less than 2%, it indicates that the heat exchange capacity of the liquid cooling plate has reached its limit. Further increasing the flow rate will not increase the heat exchange capacity, but will only increase the power consumption of the pump.

[0091] Handling measures:

[0092] The coolant pump speed is locked at the current value and will not be increased further.

[0093] If the cell temperature continues to rise at this point, shift the adjustment focus to the air-cooled side, according to F. hdp Increasing the speed of the axial cooling fan 3 enhances the heat dissipation capacity of the external fins of the finned heat sink 2, reduces the inlet temperature of the coolant, and indirectly improves the heat exchange efficiency of the liquid cooling plate 6.

[0094] If the cell temperature still exceeds 50°C after the axial cooling fan 3 reaches full speed, the power limit will be triggered, and the discharge power will be gradually reduced to ensure that the battery temperature is maintained within a safe range.

[0095] Understandably, existing methods, which rely solely on heat exchange or temperature difference for control, suffer from significant lag and misjudgment. For instance, when the cell temperature difference is small, even if the liquid cooling plate 6 performs optimally, its heat exchange will be very low. Reducing the pump speed based on this could lead to insufficient heat dissipation under subsequent high-temperature conditions. The liquid cooling plate's thermal conductivity admittance, however, eliminates the influence of temperature difference driving force through ratio calculations, accurately reflecting the efficiency of the liquid cooling plate 6 under current operating conditions. When this value consistently falls below 50% of the rated healthy value, it can be directly identified as a hardware fault such as flow channel blockage or leakage, without waiting for the temperature to rise to a threshold to trigger an alarm, thus achieving early fault warning.

[0096] Example 4, as Figures 1-6 As shown, based on Example 3, this embodiment of the invention provides a process for obtaining the remaining heat dissipation potential energy.

[0097] In the above embodiments, the process of obtaining the remaining heat dissipation potential energy specifically involves: obtaining the convective heat transfer coefficient of the finned surface of the finned radiator 2, the effective heat transfer area of ​​the fins, the third temperature difference between the average temperature of the finned surface and the ambient temperature, and the coolant outlet temperature. Based on the product of the convective heat transfer coefficient of the finned surface, the effective heat transfer area of ​​the fins, and the third temperature difference, the theoretical maximum heat dissipation on the air-cooled side is obtained. This theoretical maximum heat dissipation on the air-cooled side represents the upper limit of the heat dissipation capacity of the finned radiator 2 at the current speed of the axial cooling fan 3. The fourth temperature difference between the coolant outlet temperature and the average temperature of the finned surface is denoted as the liquid-fin heat transfer potential difference, which represents the power margin for heat transfer from the coolant to the fins.

[0098] Therefore, the remaining heat dissipation potential energy can be quantified as follows: ;

[0099] In the formula: F hdp h represents the remaining heat dissipation potential energy of the finned radiator 2, characterizing the maximum additional heat that the current air-cooling system can remove. fin A is the convective heat transfer coefficient of the fin surface. fin T represents the effective heat exchange area of ​​the fins. fin avg T represents the average surface temperature of the fins. amb The ambient temperature.

[0100] The calculation logic is based on the thermal resistance matching principle of a series heat exchange stage—the heat carried away by the coolant from the liquid cooling plate 6 needs to be transferred to the finned heat sink 2 first, and then dissipated into the environment through fin convection heat transfer. The two stages are in series, and the overall heat dissipation capacity is determined by the bottlenecks of both stages. Specifically:

[0101] Based on Newton's law of cooling (the fundamental formula for convective heat transfer), this is the standard method for calculating the theoretical maximum heat transfer on the air-cooled side:

[0102] h fin It is the convective heat transfer coefficient of the fin surface, representing the heat transfer capacity when air flows over the fins, and is positively correlated with the fan speed; A fin It is the total effective heat transfer area of ​​the fins, which is an inherent structural parameter and can be determined during the design phase. It is the driving temperature difference between the fin surface and the ambient air, which is the driving force for heat to dissipate from the fins to the environment. Multiplying these three factors together gives the theoretical maximum amount of heat that the finned heat sink 2 can dissipate to the environment at the current speed of the axial cooling fan 3, which is the theoretical maximum heat exchange capacity of the air-cooled side.

[0103] The difference is the difference between the temperature of the coolant entering the finned radiator 2 and the average temperature of the fins, representing the driving temperature difference for heat transfer from the coolant to the fins. The larger the difference, the stronger the driving force for heat transfer from the coolant to the fins, and the more heat can be transferred to the fins per unit time; the smaller the difference, the closer the temperatures of the coolant and the fins are, and the weaker the driving force for heat transfer. Even if the fins have a strong heat dissipation capacity to the environment, they cannot transfer the heat from the coolant.

[0104] The ratio is the heat transfer admittance on the fin side, which is essentially the same as... C represents the heat dissipation capacity of the air-cooled side, normalized to a standard scenario where the temperature difference between the coolant and the fins is 1K. It represents the amount of heat that the current air-cooled system can remove under a unit coolant-fin temperature difference, and is the heat transfer capacity per unit temperature difference on the air-cooled side in a series heat exchange process. ptc It refers to the heat transfer capacity per unit temperature difference on the liquid-cooled side. What we obtain is the heat transfer capacity per unit temperature difference on the air-cooled side. These two values ​​represent the capabilities of the two upstream and downstream components of the liquid-cooled-air-cooled series heat exchange system. The overall heat transfer capacity of the series system is determined by the matching relationship between the two components, not simply by the weakest link. Therefore, multiplying these two values ​​physically means multiplying the heat transfer capacity on the liquid-cooled side by the heat transfer capacity per unit temperature difference on the air-cooled side, ultimately yielding the maximum heat dissipation power that the entire liquid-cooled + air-cooled series system can currently stably handle, which is the fin heat dissipation potential energy F. hdp .

[0105] In one embodiment, on a wind tunnel test bench, the axial cooling fan 3 is controlled to operate at different speeds, and the convective heat transfer coefficient h on the fin surface is measured. fin This allows for the establishment of a speed-heat transfer coefficient calibration table, which is then pre-stored in the controller.

[0106] Further adjustment logic is based on the fin heat dissipation potential energy F. hdp Compared with the current actual heat exchange Q actual Based on this as the core principle, the specific steps are as follows:

[0107] 1. Pre-calibrate basic parameters:

[0108] Two thresholds are pre-defined:

[0109] First safety redundancy coefficient k safe1 =1.2: i.e., F hdp It needs to be at least 1.2 times the current actual heat exchange, ensuring a 20% heat dissipation redundancy, and a second safety redundancy factor k. safe2 =0.8: That is, F hdp It needs to be at least 0.8 times the current actual heat exchange capacity;

[0110] Axial flow cooling fan speed adjustment step: usually 5% of the rated speed per step, to avoid excessive speed fluctuation.

[0111] 2. Adjustment rules:

[0112] Real-time calculation of the actual heat transfer flux on the liquid cooling side of liquid cooling plate 6 (Right now The numerator of the calculation formula);

[0113] Compare F hdp With k safe1 ×Q actual and k safe2 ×Q actual Size:

[0114] If F hdp >1.2×Q actual This indicates that the air cooling redundancy is sufficient; the fan speed is reduced in steps until F... hdp Approximately 1.2 × Q actual Reduce fan energy consumption;

[0115] If 0.8×Q actual ≤F hdp ≤ 1.2×Q actual This indicates that the air cooling capacity is matched, and the current fan speed remains unchanged;

[0116] If F hdp <0.8×Q actual This indicates insufficient air cooling capacity. Increase the fan speed in increments until F... hdp Return to a safe range to prevent heat buildup that could cause the coolant temperature to rise.

[0117] Therefore, it can be understood from this embodiment that liquid cooling and air cooling are connected in series, and the overall heat dissipation capacity is not determined solely by the weakest link, but rather by the degree of matching between the two. For example, if the liquid cooling plate 6 has a strong heat exchange capacity, but the fan speed is too low, preventing heat from being dissipated from the fins to the environment, then the overall heat dissipation capacity of the system will still be limited. hdp The physical meaning lies in the heat transfer capacity C per unit temperature difference on the liquid-cooled side. ptc Based on this, the heat exchange capacity of the air-cooled side per unit liquid-fin temperature difference is multiplied, and the capabilities of the two links are normalized and integrated, thereby accurately identifying the current heat dissipation bottleneck and quantifying the additional heat load that the system can still withstand.

[0118] Example 5, as Figures 1-6 As shown in Example 4, this embodiment of the invention provides a process for obtaining the effective value of the cell heat flux density vector.

[0119] In the above embodiments, the process of obtaining the effective value of the cell heat flux density vector is as follows: The remaining heat dissipation potential energy, the effective heat transfer area of ​​the liquid cooling plate 6 in contact with the lithium battery cell 5, the cell heat flux density of each row of lithium battery cells 5, and the angle between the cell heat flux direction and the normal of the liquid cooling plate are obtained. The ratio of the remaining heat dissipation potential energy to the effective heat transfer area is recorded as the allowable heat flux threshold per unit area, which represents the maximum heat flux upper limit that the liquid cooling plate 6 can bear per unit contact area. The product of the cell heat flux density of each row of cells and the cosine of the corresponding angle is recorded as the effective heat flux of a single row, which represents the effective heat flux density that can be transferred to the liquid cooling plate 6 from the heat generated by that row of cells. The square root of the squared average of all single-row effective heat fluxes is used to obtain the root mean square value of the cell heat flux, which represents the equivalent uniform intensity of heat generation by multiple rows of cells and can amplify the risk weight of local high heat flux.

[0120] Therefore, the quantization method for the effective value of the cell heat flux density vector is as follows:

[0121] ;

[0122] In the formula: A cold,plate The effective heat exchange area between the liquid cooling plate 6 and the lithium battery cell 5 is an inherent structural parameter. This calculation involves taking the calculated maximum load capacity F of the entire air-cooled system. hdp This, when distributed across the unit heat exchange area of ​​the liquid cooling plate, yields the maximum allowable heat flux density per unit area of ​​the liquid cooling plate. Essentially, this sets an upper limit per unit area for heat generation in the battery cell.

[0123] For example, F hdp It is 2000W. The heat exchange area of ​​the liquid cooling plate is 0.5m². So the unit area can only carry a maximum heat flow of 4000W / m². If it exceeds this value, the heat dissipation system will not be able to remove the heat.

[0124] The calculated value serves as a weighting coefficient to take the capacity boundary of the heat dissipation side as a weighting factor, so as to prevent the heat generation intensity of the battery cell in subsequent calculations from deviating from the actual heat dissipation capacity range, and to ensure that the result is an effective heat generation intensity that matches the heat dissipation system.

[0125] This method is based on the root mean square statistical method of AC effective value. N is the total number of battery cells, as shown in the appendix. Figure 3 and attached Figure 4 The diagram shows two rows of battery cells, i.e., N=2, corresponding to the left and right rows respectively; H fv,i Let θ be the heat flux density of the i-th column of cells. i Let be the angle between the heat flow direction of the i-th column of cells and the normal direction of the liquid cooling plate; first, calculate the effective heat flow of each column. Taking the square root of the average value yields the equivalent DC value of the effective heat flow of the two rows of cells. This effectively converts the uneven heat generation of the two rows into a uniformly distributed equivalent heat generation intensity, preventing overheating of a single row of cells from being masked by the average temperature. The included angle θ... i It refers to the angle between the direction of the line connecting the geometric center of the i-th column of battery cells and the geometric center of the liquid cooling plate 6, and the normal direction of the contact surface between the battery cells and the liquid cooling plate 6. In engineering, it can be simplified as a structural constant based on the relative position of the battery cells and the liquid cooling plate 6.

[0126] It is the upper limit of the load per unit area on the heat dissipation side. The effective heat generation intensity on the cell side is the equivalent effective heat generation intensity. Multiplying the two yields the effective value of the cell heat flux density vector H. fv,rms , is a comprehensive heat generation characteristic value that simultaneously considers the heat dissipation system capacity and the heat generation distribution of the battery cell, representing the total effective power that the heat dissipation system actually needs to bear in the current heat generation of the battery cell. H fv,rms It will neither deviate from the actual capabilities of the heat dissipation system nor ignore the unevenness of heat generation in the battery cells.

[0127] In summary, it can be understood that heat generation in the battery cell can be considered a heat flow vector. Since the liquid cooling plate 6 is arranged between the two rows of battery cells, the heat generated by the cells does not flow entirely perpendicularly to the liquid cooling plate 6; some heat is transferred in other directions. This is achieved through the included angle θ. i By applying the cosine value of the heat flux density, the portion of heat flux that constitutes the effective load on the liquid cooling plate 6 can be extracted. Based on this, the root mean square statistical method can be used to convert the potentially non-uniform heat generation intensity in the left and right columns into an equivalent uniformly distributed heat load. This equivalent value, compared to a simple arithmetic mean, amplifies the risks associated with high heat flux on one side, avoiding the masking of potential localized overheating due to a normal average temperature.

[0128] Example 6, as Figures 1-6 As shown, based on Example 5, this embodiment of the invention provides a dynamic allocation process for the flow rate ratio of each channel of the liquid cooling plate 6.

[0129] In the above embodiments, it should first be clarified that the liquid cooling plate 6 is internally designed with two independent flow channels, corresponding to the left and right rows of battery cells respectively. The liquid cooling plate 6 is designed with H... fv,rms The process of dynamically adjusting the flow rate based on the proportion of heat flux in a single column includes:

[0130] Total flow adjustment: First, based on H fv,rms Size, matching the thermal conductivity and admittance C of the cold plate ptc The requirement is to determine the total output flow rate of the liquid cooling pump to ensure that the total heat exchange capacity meets the overall heat production demand.

[0131] Flow distribution adjustment: Calculate the proportion of effective heat flow for each row of cells. Distribute the flow rate of the left and right channels proportionally: for example, if the heat flow rate of the left column is 60% and that of the right column is 40%, then the left channel is allocated 60% of the total flow rate and the right channel is allocated 40% of the total flow rate.

[0132] Temperature calibration: If the actual temperature difference between the two rows of cells exceeds 3°C, fine-tune the flow rate ratio, allocating 5%-10% more flow rate to the row with the higher temperature, until the temperature difference returns to within 3°C.

[0133] Finally, when the effective value of the cell heat flux density vector H fv,rms Exceeding the remaining heat dissipation potential energy F hdp When the corresponding safety threshold is reached, the discharge power of the high-thermal-flow series is limited first. If the safety requirements are still not met, the power limit of the entire group is then executed.

[0134] Understandably, through a two-stage adjustment strategy of proportional flow distribution and temperature fine-tuning, this embodiment can proactively intervene and reduce the temperature difference between the two rows of cells while ensuring overall heat dissipation requirements. This can effectively suppress the problem of poor local heat dissipation, delay the performance degradation of the entire battery pack, and thus extend the cycle life of the battery pack.

[0135] Furthermore, it is understood that the specific thresholds of 0.8 (80%), 1.2 (120%), 3℃, and 5%-10% in Examples 4 and 6 are preferred values ​​determined based on thermal simulation and bench test results of typical engineering vehicle lithium battery packs. In practical applications, these thresholds can be adaptively adjusted according to the physical properties of specific cells (such as optimal operating temperature range, heat capacity, internal resistance, etc.) and system heat dissipation requirements.

[0136] Thus, a complete set of control parameters for real-time adjustment of the coolant pump speed, axial cooling fan 3 speed, and internal flow distribution of the liquid cooling plate 6 under different operating conditions has been obtained. Through the coordinated operation of Embodiments 1 to 6, the heat dissipation component can proactively increase the fan speed based on the remaining heat dissipation potential energy when the engineering vehicle is discharging at high current, thus avoiding overshoot of the battery cell temperature. Under light load or cold conditions, it can proactively reduce the speed of the pump and fan based on the thermal conductivity admittance of the cold plate and the redundancy of the remaining heat dissipation potential energy, thereby achieving on-demand power supply and significantly reducing energy consumption.

[0137] It should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should also be within the scope of protection of this invention.

Claims

1. A heat dissipation assembly for a lithium battery pack of a new energy engineering vehicle, characterized in that, include: The battery pack housing (1) has two rows of lithium battery cells (5) installed side by side inside, and a liquid cooling plate (6) installed between the two rows of lithium battery cells (5). Cooling fluid passage pipes (8) are installed on the upper and lower sides of the lithium battery cells (5). A finned heat sink (2) is fixedly installed on the outside of the battery pack housing (1). An axial flow cooling fan (3) is mounted on the finned heat sink (2). A coolant storage tank (4) is installed below the finned heat sink (2). The coolant pipe interface (7) is connected to the coolant passage pipe (8), the liquid cooling plate (6), the finned heat sink (2), and the coolant storage tank (4) in sequence to form a closed loop. Based on the matching relationship between the actual heat transfer flux of the liquid cooling plate (6) on the liquid cooling side and the core liquid driving potential difference, the thermal admittance of the cold plate is calculated, and the output flow rate of the coolant circuit is adjusted with the thermal admittance of the cold plate as a reference. Based on the coupling relationship between the thermal conductivity and admittance of the cold plate and the heat exchange capacity of the air-cooled side of the finned heat sink (2) and the heat transfer potential difference of the liquid fin, the remaining heat dissipation potential energy is calculated, and the output speed of the axial cooling fan (3) is adjusted with the remaining heat dissipation potential energy as a reference. Based on the root mean square fusion relationship between the remaining heat dissipation potential energy and the heat generation distribution of each column of lithium battery cells (5), the effective value of the cell heat flux density vector is calculated. With the effective value of the cell heat flux density vector as a reference, the flow rate ratio of each channel of the liquid cooling plate (6) is dynamically allocated.

2. The heat dissipation assembly for a lithium battery pack of a new energy engineering vehicle according to claim 1, characterized in that, The process of obtaining the thermal admittance of the cold plate includes: The coolant mass flow rate, coolant specific heat capacity at constant pressure, first temperature difference between entering and exiting the liquid cooling plate (6), and the average cell temperature and average coolant temperature of the lithium battery cell (5) are obtained. Based on the product of coolant mass flow rate, coolant specific heat capacity at constant pressure and first temperature difference, the actual heat transfer flux on the liquid cooling side is obtained. The actual heat transfer flux on the liquid cooling side characterizes the total heat carried away by the coolant from the cell surface per unit time. Based on the second temperature difference between the average temperature of the battery cell and the average temperature of the coolant, the core-liquid driving potential difference is obtained, which characterizes the power margin for heat transfer from the battery cell to the coolant. The ratio of the actual heat transfer flux on the liquid cooling side to the core liquid driving potential difference is denoted as the thermal admittance of the cold plate. The thermal admittance of the cold plate characterizes the effective heat transfer capacity of the liquid cooling plate (6) under a unit temperature difference.

3. The heat dissipation assembly for a lithium battery pack of a new energy engineering vehicle according to claim 2, characterized in that, The adjustment process of the coolant circuit output flow rate with reference to the thermal admittance of the cold plate includes: Obtain the preset rated health admittance value; When the thermal conductivity of the cold plate is lower than 80% of the rated healthy admittance, it is determined that the flow is insufficient. The speed of the coolant pump is increased according to the proportion of the health gap, but not exceeding the rated speed of the pump. When the thermal conductivity of the cold plate is higher than 120% of the rated healthy admittance, it is determined to be an excess flow. The coolant pump speed is reduced according to the health redundancy ratio, and the minimum speed is not lower than the minimum stable speed of the pump. When the thermal conductivity of the cold plate is lower than 50% of the rated health admittance for three consecutive control cycles, it is determined to be a liquid cooling circuit fault, triggering a first-level alarm, increasing the axial cooling fan (3) to full speed, and limiting the discharge power of the lithium battery cell (5) to 60% of the rated value.

4. A heat dissipation component for a lithium battery pack in a new energy engineering vehicle according to claim 2, characterized in that, The process of acquiring the remaining heat dissipation potential energy includes: The convective heat transfer coefficient of the fin surface, the effective heat transfer area of ​​the fin, the third temperature difference between the average temperature of the fin surface and the ambient temperature, and the outlet temperature of the coolant of the finned radiator (2) are obtained. Based on the product of the convective heat transfer coefficient of the fin surface, the effective heat transfer area of ​​the fin and the third temperature difference, the theoretical maximum heat dissipation of the air-cooled side is obtained. The theoretical maximum heat dissipation of the air-cooled side represents the upper limit of the heat dissipation capacity of the finned heat sink (2) under the current axial flow cooling fan (3) speed. The fourth temperature difference between the coolant outlet temperature and the average surface temperature of the fins is denoted as the liquid fin heat transfer potential difference, which represents the power margin for heat transfer from the coolant to the fins. The ratio of the theoretical maximum heat dissipation of the air-cooled side to the heat transfer potential difference of the liquid fins is denoted as the heat transfer capacity per unit temperature difference of the air-cooled side. The product of the thermal admittance of the cold plate and the heat transfer capacity per unit temperature difference of the air-cooled side is denoted as the residual heat dissipation potential energy. The residual heat dissipation potential energy characterizes the maximum continuous heat dissipation power that the liquid-air-cooled series system can stably bear.

5. A heat dissipation component for a lithium battery pack in a new energy engineering vehicle according to claim 4, characterized in that, The process of obtaining the convective heat transfer coefficient of the fin surface includes: A calibration table of the rotational speed and convective heat transfer coefficient of the axial cooling fan (3) is pre-stored, and the calibration table is calibrated on a test bench through a wind tunnel test; The current speed of the axial cooling fan (3) is collected in real time, and the corresponding convective heat transfer coefficient of the fin surface is obtained by looking up the table.

6. A heat dissipation component for a lithium battery pack in a new energy engineering vehicle according to claim 4, characterized in that, The process by which the axial cooling fan (3) adjusts its output speed with reference to the remaining heat dissipation potential energy includes: When the remaining heat dissipation potential energy is lower than 80% of the actual heat exchange flux on the current liquid cooling side, it is determined that the air cooling capacity is insufficient, and the fan speed is increased proportionally to the heat dissipation margin gap, but not exceeding the rated fan speed. When the remaining heat dissipation potential energy is higher than 120% of the actual heat exchange flux on the current liquid cooling side, it is determined that the air cooling redundancy is excessive, and the fan speed is reduced according to the proportion of the heat dissipation redundancy, with a minimum not lower than the minimum stable fan speed. When the remaining heat dissipation potential energy increases by less than 2% with the increase of fan speed, it is determined that the air cooling is saturated, the speed of the axial flow cooling fan (3) is locked, and the power limit threshold of the lithium battery cell (5) is triggered.

7. A heat dissipation component for a lithium battery pack in a new energy engineering vehicle according to claim 4, characterized in that, The process of obtaining the effective value of the cell heat flux density vector includes: The remaining heat dissipation potential energy, the effective heat exchange area of ​​the liquid cooling plate (6) in contact with the lithium battery cell (5), the cell heat flux density of each column of lithium battery cells (5), and the angle between the cell heat flux direction and the normal of the liquid cooling plate are obtained. The ratio of the remaining heat dissipation potential energy to the effective heat exchange area is recorded as the allowable heat flow threshold per unit area. The allowable heat flow threshold per unit area characterizes the maximum heat flow limit that the liquid cooling plate (6) can bear per unit contact area. The product of the heat flux density of each row of cells and the cosine of the corresponding angle is recorded as the effective heat flux of a single row. The effective heat flux of a single row represents the effective heat flux density that can be transferred to the liquid cooling plate (6) in the heat generated by the cells in that row. The root mean square value of the cell heat flux is obtained by taking the square root of the average of the squares of all effective heat fluxes in a single column. The root mean square value of the cell heat flux represents the equivalent uniform intensity of heat generation in multiple columns of cells and amplifies the risk weight of local high heat flux. The product of the permissible heat flux threshold per unit area and the root mean square value of the cell heat flux is denoted as the effective value of the cell heat flux density vector. The effective value of the cell heat flux density vector represents the effective heat load of the cell that matches the current heat dissipation capacity.

8. A heat dissipation component for a lithium battery pack in a new energy engineering vehicle according to claim 7, characterized in that, The process of obtaining the cell heat flux density includes: The charging and discharging current of the lithium battery cell (5) is collected in real time, and the current DC internal resistance of each cell is obtained by querying. The cell heat flux density of a cell is obtained by dividing the product of the DC internal resistance of each cell and the square of the current by the contact area between the cell and the liquid cooling plate (6).

9. A heat dissipation component for a lithium battery pack in a new energy engineering vehicle according to claim 7, characterized in that, The process by which the liquid cooling plate (6) dynamically allocates the flow rate ratio of each channel with reference to the effective value of the cell heat flux density vector includes: Based on the proportion of effective heat flow in each row of cells, the flow rate of the corresponding side channel of the liquid cooling plate (6) is allocated accordingly. When the temperature difference between the two columns of lithium battery cells (5) exceeds 3°C, an additional 5%-10% flow rate is allocated to the flow channel of the column with the higher temperature until the temperature difference drops back to within 3°C. When the effective value of the cell heat flux density vector exceeds the safety threshold corresponding to the remaining heat dissipation potential energy, the discharge power of the high heat flux column is limited first. If the safety requirements are still not met, the power limit of the entire group is then executed.

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