Liquid-cooled power battery module

Abstract

The invention discloses a liquid-cooled power battery module which comprises a shell, an accommodating space is formed in the shell, and a fluid inlet and a fluid outlet are formed in the two ends of the shell respectively; the battery pack comprises a plurality of battery units which are attached to one another, and an overcurrent gap is reserved between the battery pack and the inner wall of the shell; the multiple heat dissipation fins are installed on the inner wall of the shell in an array mode, and the heat dissipation fins are arranged in the overflowing gaps; the heat dissipation fins are in a water drop shape, and the two ends of each heat dissipation fin are a head with the larger width and a tail with the smaller width respectively. The heat dissipation fins are arranged in the shell, so that the flowing path of cooling liquid can be changed, the flowing speed of the cooling liquid is reduced, the contact time of the cooling liquid and the battery pack is prolonged, and the heat dissipation efficiency is improved; moreover, the heat dissipation fins are in the shape of water drops and can guide the cooling liquid to be dispersed to all areas on the surface of the battery pack, so that the consistency of temperature drop is improved, and the situation of uneven heat dissipation is reduced. The invention relates to the technical field of battery thermal management.

Description

Technical Field

[0001] The present application relates to the technical field of battery thermal management, and in particular to a liquid-cooled power battery module. Background Art

[0002] The battery thermal management system is a system used to regulate and control the battery temperature, ensuring that the battery operates within a safe and efficient temperature range. Lithium-ion power batteries usually operate under high-rate discharge conditions to meet the power needs of the vehicle. Due to the high temperature sensitivity of lithium-ion power batteries, if the heat is not dissipated in time, the battery temperature will rise and become uneven, resulting in battery capacity decay and poor performance. At high temperatures, lithium batteries will self-discharge, resulting in a decrease in battery capacity and power. Solving the thermal problems of lithium-ion batteries is very important because it is closely related to their safety, performance and state estimation. When the battery is fully charged, if the battery management system cannot block the charging current in time, it will cause the battery to overcharge, which may lead to thermal runaway and its spread, and eventually a serious battery fire accident. The thermal management system manages the thermal behavior of the battery through heating, cooling and temperature monitoring to prevent overheating or overcooling, thereby improving the performance, safety and life of the battery.

[0003] In the design of the thermal management system, it is necessary to ensure the temperature uniformity of the battery pack and the single battery, that is, the temperature difference is kept within 5°C. Direct liquid cooling (immersion cooling) is a thermal management method with extremely high cooling efficiency. The battery is directly and completely immersed in the dielectric cooling liquid, and there is a large area of ​​direct contact with the coolant. The sensible or latent heat of the coolant can be used to achieve effective heat dissipation of the battery pack. This design eliminates the thermal resistance caused by the indirect contact between the cooling medium and the battery surface, thereby constructing a uniform, high heat capacity heat transfer path. Therefore, the immersion cooling system has a better cooling effect than other systems.

[0004] Currently, in immersion cooling systems, the flow of cooling liquid is mainly a relatively simple flow from the inlet through the battery module and then out of the outlet. In a traditional immersion thermal management system without an additional composite structure, the rapid flow of fluid through the battery module may cause the heat in some areas of the battery module to not be taken away, resulting in a problem of decreased temperature uniformity. In addition, the battery located near the fluid outlet cannot obtain the same heat dissipation effect as the inlet, and the effect of controlling the maximum temperature drop becomes worse. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a liquid-cooled power battery module, which can improve the consistency of the temperature drop of the battery module and improve the temperature drop effect at the fluid outlet.

[0006] The liquid-cooled power battery module according to an embodiment of the present application includes:

[0007] A shell having an accommodating space therein, and two ends of the shell are respectively provided with a fluid inlet and a fluid outlet connected to the accommodating space;

[0008] A battery pack, comprising a plurality of battery cells attached to each other, the battery pack being placed in the accommodation space, with a flow gap being left between the battery pack and the inner wall of the shell;

[0009] The heat dissipation fins are multiple and are installed in an array on the inner wall of the shell, and the heat dissipation fins are arranged in the flow gap; the heat dissipation fins are in the shape of a water drop, and the two ends of the heat dissipation fins are respectively a head with a wider width and a tail with a smaller width, and the head of the heat dissipation fin is the flow-facing end.

[0010] The liquid-cooled power battery module according to the embodiment of the present application has at least the following beneficial effects: by arranging heat dissipation fins inside the shell, the flow path of the coolant can be changed, the flow rate of the coolant can be reduced to prolong its contact time with the battery pack, and the heat dissipation efficiency can be improved; moreover, the heat dissipation fins are in the shape of water drops, which can guide the coolant to spread to various areas on the surface of the battery pack, thereby improving the consistency of temperature drop and reducing the occurrence of uneven heat dissipation.

[0011] According to some embodiments of the present application, the heat dissipation fins are attached to the battery pack.

[0012] According to some embodiments of the present application, the heat dissipation fins are divided into a plurality of heat dissipation fin groups along the x-direction, and two adjacent heat dissipation fin groups are arranged alternately.

[0013] According to some embodiments of the present application, the distance between two adjacent heat dissipation fin groups is 1 to 2 times the length of the heat dissipation fins.

[0014] According to some embodiments of the present application, the heat dissipation fins in the same heat dissipation fin group are arranged equidistantly along the y direction.

[0015] According to some embodiments of the present application, in the same heat dissipation fin group, the distance between two adjacent heat dissipation fins is 2 to 3 times the width of the heat dissipation fin.

[0016] According to some embodiments of the present application, the width of the heat dissipation fin satisfies the following relationship:

[0017] (x 2 +y 2 ) 2 -2x(x 2 +y 2 )+ny 2 =0;

[0018] Where n≥0.

[0019] According to some embodiments of the present application, the parameter equation of the width of the heat dissipation fin is:

[0020]

[0021] According to some embodiments of the present application, each of the battery cells is equipped with a pressure relief valve.

[0022] According to some embodiments of the present application, the battery pack further includes a heat insulation plate, which is installed between two adjacent battery cells and is used to isolate heat transfer between the battery cells.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide further understanding of the technical solution disclosed in the present application and constitute a part of the specification. Together with the embodiments disclosed in the present application, they are used to explain the technical solution disclosed in the present application and do not constitute a limitation on the technical solution disclosed in the present application.

[0025] Figure 1 This is a disassembled diagram of the liquid-cooled power battery module of an embodiment of the present application;

[0026] Figure 2 This is a front view of the heat exchange fins in the liquid-cooled power battery module of the embodiment of the present application;

[0027] Figure 3 This is a schematic diagram of the arrangement of heat exchange fins in a liquid-cooled power battery module according to an embodiment of the present application;

[0028] Figure 4 This is a disassembled diagram of the battery pack in the liquid-cooled power battery module of an embodiment of the present application.

[0029] Reference numerals: 100 - housing, 110 - fluid inlet, 120 - fluid outlet, 200 - battery pack, 210 - battery cell, 211 - pressure relief valve, 220 - heat shield, 300 - heat dissipation fins, 310 - head, 320 - tail. DETAILED DESCRIPTION

[0030] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0031] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0032] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0033] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0034] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0035] The battery thermal management system is a system used to regulate and control the battery temperature, ensuring that the battery operates within a safe and efficient temperature range. Lithium-ion power batteries usually operate under high-rate discharge conditions to meet the power needs of the vehicle. Due to the high temperature sensitivity of lithium-ion power batteries, if the heat is not dissipated in time, the battery temperature will rise and become uneven, resulting in battery capacity decay and poor performance. At high temperatures, lithium batteries will self-discharge, resulting in a decrease in battery capacity and power. Solving the thermal problems of lithium-ion batteries is very important because it is closely related to their safety, performance and state estimation. When the battery is fully charged, if the battery management system cannot block the charging current in time, it will cause the battery to overcharge, which may lead to thermal runaway and its spread, and eventually a serious battery fire accident. The thermal management system manages the thermal behavior of the battery through heating, cooling and temperature monitoring to prevent overheating or overcooling, thereby improving the performance, safety and life of the battery.

[0036] In the design of the thermal management system, it is necessary to ensure the temperature uniformity of the battery pack and the single battery, that is, the temperature difference is kept within 5°C. Direct liquid cooling (immersion cooling) is a thermal management method with extremely high cooling efficiency. The battery is directly and completely immersed in the dielectric cooling liquid, and there is a large area of ​​direct contact with the coolant. The sensible or latent heat of the coolant can be used to achieve effective heat dissipation of the battery pack. This design eliminates the thermal resistance caused by the indirect contact between the cooling medium and the battery surface, thereby constructing a uniform, high heat capacity heat transfer path. Therefore, the immersion cooling system has a better cooling effect than other systems.

[0037] Currently, in immersion cooling systems, the flow of cooling liquid is mainly a relatively simple flow from the inlet through the battery module and then out of the outlet. In a traditional immersion thermal management system without an additional composite structure, the rapid flow of fluid through the battery module may cause the heat in some areas of the battery module to not be taken away, resulting in a problem of decreased temperature uniformity. In addition, the battery located near the fluid outlet cannot obtain the same heat dissipation effect as the inlet, and the effect of controlling the maximum temperature drop becomes worse.

[0038] In this regard, the present application proposes a liquid-cooled power battery module. By arranging heat dissipation fins 300 inside the shell 100, the flow path of the coolant can be changed, the flow rate of the coolant can be reduced to prolong its contact time with the battery pack 200, and the heat dissipation efficiency can be improved; moreover, the heat dissipation fins 300 are in the shape of water drops, which can guide the coolant to spread to various areas on the surface of the battery pack 200, thereby improving the consistency of temperature drop and reducing the occurrence of uneven heat dissipation.

[0039] Reference Figure 1 The liquid-cooled power battery module in the embodiment of the present application includes a shell 100, a battery pack 200 and heat dissipation fins 300. The shell 100 and the battery pack 200 are the main structures of the liquid-cooled power battery module. The shell 100 is a closed box structure for accommodating the battery pack 200 and containing coolant. The coolant can flow in the shell 100 and take away the heat emitted by the battery pack 200 when working, thereby playing a role in cooling the battery pack 200. The heat dissipation fins 300 are arranged on the inner wall of the shell 100 to guide the flow direction of the coolant and to disturb the coolant, thereby reducing the flow rate of the coolant, so that the coolant is in full contact with the battery pack 200, and the heat dissipation efficiency is improved.

[0040] Specifically, the shell 100 is composed of a plurality of plates, and adjacent plates are connected by welding to ensure sealing. A housing space is provided inside the shell 100, and a fluid inlet 110 and a fluid outlet 120 connected to the housing space are respectively provided at both ends of the shell 100. During normal operation, the coolant enters the housing space from the fluid inlet 110 to exchange heat with the battery pack 200. After the heat exchange is completed, the heated coolant is discharged from the fluid outlet 120, thereby taking away the heat from the battery pack 200. The discharged coolant enters the external coolant circulation system for cooling again, and then is re-input into the fluid inlet 110 to complete the circulation of the coolant.

[0041] It is worth noting that the height of the fluid inlet 110 on the housing 100 is lower than the height of the fluid outlet 120 , so that the flow path of the coolant in the housing 100 is from bottom to top, and can fully exchange heat with the battery pack 200 .

[0042] The battery pack 200 includes a plurality of battery cells 210 that are attached to each other, and each battery cell 210 supplies power to an external power-consuming device, including but not limited to an electric car, an electric motorcycle, an electric bicycle or other electric vehicles. The battery pack 200 is placed in the accommodation space, but it is worth noting that the surface of the battery pack 200 is not completely attached to the inner wall of the housing 100, and a flow gap is left between the battery pack 200 and the inner wall of the housing 100 for the flow of coolant.

[0043] There are multiple heat dissipation fins 300 installed in an array on the inner wall of the housing 100, and the heat dissipation fins 300 are arranged in the flow gap. In some embodiments, the heat dissipation fins 300 are not attached to the battery pack 200, and there is still a gap between the heat dissipation fins 300 and the battery pack 200, and the coolant can flow through the gap between the heat dissipation fins 300 and the battery pack 200; in other embodiments, the heat dissipation fins 300 are attached to the battery pack 200, and the coolant can only flow through the gaps between the heat dissipation fins 300, thereby simplifying the flow path of the coolant and reducing turbulence and turbulence.

[0044] It is worth noting that referring to Figure 2 The heat dissipation fin 300 is in the shape of a water drop. When water flows through the side of the heat dissipation fin 300, its water drop shape can reduce the generation of turbulence and turbulence. The two ends of the heat dissipation fin 300 are respectively a head 310 with a larger width and a tail 320 with a smaller width. The head 310 of the heat dissipation fin 300 is the flow-facing end. The water first contacts the head 310 and flows along the side of the heat dissipation fin 300 to the tail 320.

[0045] Further, for the specific arrangement of the heat dissipation fins 300, refer to Figure 3The heat dissipation fins 300 are divided into a plurality of heat dissipation fin groups along the x direction, and two adjacent heat dissipation fin groups are arranged in a staggered manner. Thus, the flow path of the coolant becomes tortuous through each staggered heat dissipation fin group, extending the flow distance of the coolant, thereby increasing the heat exchange time between the coolant and the battery pack 200 and improving the heat exchange efficiency.

[0046] Specifically, the distance between two adjacent heat sink fin groups is 1 to 2 times, preferably 1.5 times, the length of the heat sink fin 300 to avoid blocking the coolant discharge due to too small a spacing, or too fast a spacing causing the coolant to be discharged, thereby reducing the heat exchange efficiency.

[0047] Furthermore, the heat sinks 300 in the same heat sink fin group are equidistantly arranged along the y direction. Moreover, in the same heat sink fin group, the spacing between two adjacent heat sink fins 300 is 2 to 3 times, preferably 3 times, of the width of the heat sink fin 300, to avoid blocking the discharge of the coolant due to too small a spacing, or too fast discharge of the coolant due to too large a spacing, thereby reducing the heat exchange efficiency.

[0048] Furthermore, the width of the heat dissipation fin 300 satisfies the following relationship:

[0049] (x 2 +y 2 ) 2 -2x(x 2 +y 2 )+ny 2 =0;

[0050] Where n≥0. n is called the expansion coefficient of the water drop curve. When n=0, the curve is a standard circle. As n increases, the curve becomes flatter. The value of n can be adjusted according to actual conditions. The larger the n value, the thinner the shape of the heat sink fin 300, the worse the deceleration effect on the water flow, and the faster the flow rate of the coolant; the smaller the n value, the wider the shape of the heat sink fin 300, the better the deceleration effect on the water flow, and the slower the flow rate of the coolant.

[0051] Furthermore, the parameter equation of the width of the heat sink fin is:

[0052]

[0053] when When , the parametric equation has mutually symmetrical singular points.

[0054] It is easy to understand that the shape of the heat dissipation fin 300 can be scaled as a whole under the premise of meeting the above equation. At the same time, considering that the sharp geometric structure of the tail 320 is difficult to achieve in actual processing, the tail 320 can be rounded.

[0055] Further, refer to Figure 4 For the battery pack 200 , each battery cell 210 therein is installed with a pressure relief valve 211 , so that when the battery cell 210 becomes abnormally hot, the pressure relief valve 211 can urgently discharge the gas therein, thereby reducing the pressure in the battery cell 210 and protecting the battery cell 210 .

[0056] Furthermore, the battery pack 200 also includes a heat shield 220 , which is installed between two adjacent battery cells 210 to block heat transfer between the battery cells 210 . The heat shield 220 is also used to assist in suppressing the spread of thermal runaway.

[0057] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A liquid-cooled power battery module, characterized in that: include: A shell having an accommodating space therein, and two ends of the shell are respectively provided with a fluid inlet and a fluid outlet connected to the accommodating space; A battery pack, comprising a plurality of battery cells attached to each other, the battery pack being placed in the accommodation space, with a flow gap being left between the battery pack and the inner wall of the shell; The heat dissipation fins are multiple and are installed in an array on the inner wall of the shell, and the heat dissipation fins are arranged in the flow gap; the heat dissipation fins are in the shape of a water drop, and the two ends of the heat dissipation fins are respectively a head with a wider width and a tail with a smaller width, and the head of the heat dissipation fin is the flow-facing end.

2. The liquid-cooled power battery module according to claim 1, characterized in that: The heat dissipation fins are attached to the battery pack.

3. The liquid-cooled power battery module according to claim 1, characterized in that: The heat dissipation fins are divided into a plurality of heat dissipation fin groups along the x direction, and two adjacent heat dissipation fin groups are arranged alternately.

4. The liquid-cooled power battery module according to claim 3, characterized in that: The distance between two adjacent heat dissipation fin groups is 1 to 2 times the length of the heat dissipation fins.

5. The liquid-cooled power battery module according to claim 3, characterized in that: The heat dissipation fins in the same heat dissipation fin group are arranged equidistantly along the y direction.

6. The liquid-cooled power battery module according to claim 5, characterized in that: In the same heat dissipation fin group, the distance between two adjacent heat dissipation fins is 2 to 3 times the width of the heat dissipation fin.

7. The liquid-cooled power battery module according to claim 1, characterized in that: The width of the heat dissipation fins satisfies the following relationship: (x) 2 +y 2 ) 2 -2x(x 2 +y 2 )+the 2 =0; Where n≥0.

8. The liquid-cooled power battery module according to claim 7, characterized in that: The parametric equation for the width of the heat sink fin is:

9. The liquid-cooled power battery module according to claim 1, characterized in that: Each of the battery cells is equipped with a pressure relief valve.

10. The liquid-cooled power battery module according to claim 1, characterized in that: The battery pack further includes a heat insulation plate installed between two adjacent battery cells to isolate heat transfer between the battery cells.

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