Battery pack

Abstract

The utility model discloses a battery pack, which comprises a heat management device and a single battery, the heat management device is attached to the outer wall of the single battery, the heat management device comprises a substrate, a heat exchange tube group is arranged in the substrate, the heat exchange tube group comprises a plurality of first heat exchange tubes, the plurality of first heat exchange tubes are graded, the total stage number of the plurality of first heat exchange tubes is N, the first-stage first heat exchange tubes are communicated with the outside of the substrate, the number of the (n-1) th-stage first heat exchange tubes is smaller than that of the nth-stage first heat exchange tubes, the (n-1) th-stage first heat exchange tubes are communicated with the nth-stage first heat exchange tubes, and heat exchange fluid is conveyed to the nth-stage first heat exchange tubes from the (n-1) th-stage first heat exchange tubes; a phase change energy storage layer is arranged between the first heat exchange tube and the inner wall surface of the substrate, N and n are natural numbers, and N is Ngt; 3, 1lt; n < = N. The battery pack is small in pressure drop of the heat exchange fluid, low in energy consumption, high in heat exchange efficiency and uniform in heat transfer.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a battery pack. Background Art

[0002] Lithium-ion batteries are very sensitive to temperature. Working at too high or too low temperatures will damage the cycle life, reliability and safety of the batteries, and seriously impair their charging and discharging capabilities. During the operation of the batteries, polarization reactions and chemical reactions will generate a large amount of heat. If this part of the heat is not removed in time, it will cause the temperature of the batteries to rise rapidly, thus affecting the safe use of the batteries.

[0003] Currently, the methods applied to battery thermal management systems mainly include air cooling, liquid cooling, and phase change cooling. The air-cooling structure is simple, but the heat dissipation efficiency is average. Phase change cooling uses the heat absorption during the phase change process of phase change materials to achieve the purpose of temperature control. However, in the case of pure phase change cooling, after complete phase change occurs, overheating will occur because the latent heat of phase change has reached the maximum value, which will lead to the loss of the phase change cooling effect, and the batteries may continue to heat up or even experience thermal runaway. The liquid cooling plate is the most widely used method. The liquid cooling plate exchanges heat between the coolant flowing through the heat exchange tubes inside the plate and the inner wall to take away the heat transferred by the batteries to achieve the purpose of cooling. Therefore, the design of the heat exchange tubes is directly related to the cooling efficiency. At present, although the traditional straight-channel cold plate has a certain cooling effect on the heat dissipation of lithium-ion batteries, it has the disadvantages of high pressure drop, high energy consumption, and temperature non-uniformity. Summary of the Utility Model

[0004] This application provides a battery pack to solve the technical problems of high pressure drop, high energy consumption, and temperature non-uniformity existing in the straight-channel cold plate. The technical solutions are as follows:

[0005] The battery pack of the embodiment of this application includes a thermal management device and single cells. The thermal management device is attached to the outer wall of the single cells.

[0006] The thermal management device includes a substrate. An accommodation cavity is provided inside the substrate. A first heat exchange tube group is provided in the accommodation cavity. The first heat exchange tube group includes a plurality of first heat exchange tubes. The plurality of first heat exchange tubes are classified. The total number of levels of the plurality of first heat exchange tubes is N. The first-level first heat exchange tube is communicated with the outside of the substrate. The number of the (n - 1)-level first heat exchange tubes is less than the number of the n-level first heat exchange tubes. The (n - 1)-level first heat exchange tubes are respectively communicated with a plurality of n-level first heat exchange tubes. The heat exchange fluid is transported from the (n - 1)-level first heat exchange tube to the n-level first heat exchange tube. The substrate has an inner wall surface. A phase change energy storage layer is provided between the first heat exchange tube and the inner wall surface.

[0007] Wherein, N and n are natural numbers, and N > 3, 1 < n ≤ N.

[0008] Optionally, the first heat exchange tube of the nth stage is inclined with respect to the flow direction of the heat exchange fluid in the first heat exchange tube of the (n-1)th stage, and the inclination angle is an acute angle.

[0009] Optionally, a second heat exchange tube is further arranged in the accommodation cavity. The second heat exchange tube communicates with the outside of the substrate. The first heat exchange tube of the Nth stage communicates with the second heat exchange tube, and a phase change energy storage layer is arranged between the second heat exchange tube and the inner wall surface.

[0010] Optionally, a second heat exchange tube group is further arranged in the accommodation cavity. The second heat exchange tube group includes a plurality of second heat exchange tubes. The plurality of second heat exchange tubes are classified. The total number of stages of the plurality of second heat exchange tubes is I. The first-stage second heat exchange tube communicates with the outside of the substrate. The number of the (i-1)th stage second heat exchange tubes is less than the number of the ith stage second heat exchange tubes. The (i-1)th stage second heat exchange tubes are respectively connected to a plurality of ith stage second heat exchange tubes. The Ith stage second heat exchange tube is connected to the first heat exchange tube of the Nth stage. The heat exchange fluid is transported from the ith stage second heat exchange tube to the (i-1)th stage second heat exchange tube.

[0011] Wherein, I and i are natural numbers, and I>1, 1<i≤I.

[0012] Optionally, the Ith stage second heat exchange tube is connected to the first heat exchange tube of the Nth stage in a one-to-one correspondence.

[0013] Optionally, the substrate has a first end wall and a second end wall arranged opposite to each other and a side wall surrounding the first end wall and the second end wall. The side wall is respectively connected to the first end wall and the second end wall. The first-stage first heat exchange tube communicates with the outside of the substrate at the side wall.

[0014] Optionally, the substrate has a first end wall and a second end wall arranged opposite to each other and a side wall surrounding the first end wall and the second end wall. The side wall is respectively connected to the first end wall and the second end wall. The second heat exchange tube communicates with the outside of the substrate at the side wall.

[0015] Optionally, the substrate has a first end wall and a second end wall arranged opposite to each other and a side wall surrounding the first end wall and the second end wall. The side wall includes a first wall portion, a second wall portion, a third wall portion and a fourth wall portion respectively connected to the first end wall and the second end wall. One end of the first wall portion is connected to one end of the second wall portion to form a first corner portion. One end of the third wall portion is connected to one end of the fourth wall portion to form a second corner portion. The first corner portion and the second corner portion are arranged diagonally. The first-stage first heat exchange tube communicates with the outside of the substrate at the first corner portion. The second heat exchange tube communicates with the outside of the substrate at the second corner portion.

[0016] Optionally, the second-stage first heat exchange tube is located in the middle of the substrate. The second-stage second heat exchange tube of the second heat exchange tube group is located outside the second-stage first heat exchange tube. The nth-stage first heat exchange tube is located between the second-stage first heat exchange tube and the second-stage second heat exchange tube.

[0017] Among them, n > 2.

[0018] Optionally, the single battery has a first direction and a second direction arranged vertically, and a pole column is arranged at one end of the single battery along the first direction;

[0019] The thermal management device is arranged on the end side of the single battery facing away from the pole column; or

[0020] The thermal management device is arranged on one side of the single battery in the second direction.

[0021] The battery pack of the present application has at least the following beneficial effects:

[0022] 1. For the battery pack of the present application, by arranging a heat exchange tube group including at least four - stage heat exchange tubes in the substrate, the upper - level heat exchange tubes are communicated with a plurality of lower - level heat exchange tubes, thus creating a multi - branch heat exchange tube group structure in the substrate, which can reduce the pressure loss of the heat exchange fluid in the heat exchange tube group, resulting in a smaller pressure drop, contributing to energy consumption savings and improved heat exchange efficiency;

[0023] 2. For the battery pack of the present application, by arranging a phase - change energy storage layer between the heat exchange tube and the inner wall surface of the substrate, the characteristic that the phase - change energy storage material absorbs heat during the phase - change process can be utilized, thereby reducing the battery temperature and improving the temperature uniformity; the combination of the phase - change energy storage material and the heat exchange tube group realizes the reduction of the battery temperature, combining the advantages of both, which can increase the contact area and distribution uniformity between the heat exchange tube and the single battery, effectively improve the dissipation capacity, is conducive to uniform and rapid heat transfer to the single battery, and the flow of the heat exchange fluid can also reduce the failure of the phase - change energy storage material after reaching the phase - change temperature. Description of the Drawings

[0024] The following, in combination with the drawings, through a detailed description of the specific embodiments of the present application, will make the technical solutions and other beneficial effects of the present application obvious.

[0025] Figure 1 is a schematic side - view structure diagram of a thermal management device provided by an embodiment of the present application;

[0026] Figure 2 is a schematic internal structure diagram of a thermal management device provided by an embodiment of the present application before setting the porous carrier and the phase - change energy storage material;

[0027] Figure 3 is a schematic internal structure diagram of a thermal management device provided by an embodiment of the present application after setting the porous carrier and the phase - change energy storage material;

[0028] Figure 4 is a schematic side - view structure diagram of a square battery provided by an embodiment of the present application;

[0029] Figure 5Schematic perspective view of the thermal management device provided by an embodiment of the present application when disposed on the side of a square battery;

[0030] Figure 6 Schematic top view of the thermal management device provided by an embodiment of the present application when disposed on the side of a square battery;

[0031] Figure 7 and Figure 8 Schematic side views of the thermal management device provided by an embodiment of the present application when disposed on the side of a square battery;

[0032] Figure 9 Schematic perspective view of the thermal management device provided by another embodiment of the present application when disposed below the square battery;

[0033] Figure 10 Schematic side view of the thermal management device provided by another embodiment of the present application when disposed below the square battery.

[0034] Reference numerals: 1 - thermal management device, 11 - substrate, 111 - accommodation cavity, 112 - inner wall surface, 113 - first end wall, 114 - second end wall, 115 - side wall, 1151 - first wall portion, 1152 - second wall portion, 1153 - third wall portion, 1154 - fourth wall portion, 1155 - first corner portion, 1156 - second corner portion, 1157 - fluid inlet, 1158 - fluid outlet, 12 - first heat exchange tube group, 121 - first heat exchange tube, 1211 - first-stage first heat exchange tube, 1212 - second-stage first heat exchange tube, 1213 - third-stage first heat exchange tube, 1214 - fourth-stage first heat exchange tube, 13 - phase change energy storage layer, 131 - phase change energy storage material, 132 - porous carrier, 14 - second heat exchange tube group, 141 - second heat exchange tube, 1411 - first-stage second heat exchange tube, 1412 - second-stage second heat exchange tube, 1413 - third-stage second heat exchange tube, 1414 - fourth-stage second heat exchange tube, 2 - single cell, 21 - terminal post, 22 - large wall surface, 3 - connection layer, Z - first direction, X - second direction. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0036] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the term "and / or" in this article is merely an association relationship describing associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after without special explanation. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0037] Please refer to Figure 2 、 Figure 5 Embodiments of the present application provide a battery pack, which includes a box body (not shown in the figure), a thermal management device 1, and single cells 2. The thermal management device 1 and the single cells 2 are disposed in the box body. The thermal management device 1 abuts against the outer wall of the single cells 2. Since the specific structure of the box body and the setting manners between the thermal management device 1 and the single cells 2 and the box body can all be realized by the prior art and are not the key points protected by the present application, they will not be elaborated in this embodiment.

[0038] The thermal management device 1 includes a substrate 11, and a receiving cavity 111 is provided in the substrate 11. A first heat exchange tube group 12 is provided in the receiving cavity 111, and the first heat exchange tube group 12 includes a plurality of first heat exchange tubes 121. The first heat exchange tubes 121 can be fixedly connected to the substrate 11 by welding or the like, or the first heat exchange tubes 121 are formed on the substrate 11 by injection molding or the like. Since the specific setting manner of the first heat exchange tubes 121 can be realized by the prior art and is not the key point protected by the present application, it will not be elaborated in the present application.

[0039] The plurality of first heat exchange tubes 121 are classified, and the total number of levels of the plurality of first heat exchange tubes 121 is N. The first-stage first heat exchange tube 1211 communicates with the outside of the substrate 11. Specifically, a fluid inlet 1157 communicating its outside and the receiving cavity 111 is provided on the substrate 11, the first-stage first heat exchange tube 1211 communicates with the fluid inlet 1157, and the heat exchange fluid is transported to the first-stage first heat exchange tube 1211 through the fluid inlet 1157. The number of the (n - 1)-stage first heat exchange tubes is less than the number of the n-stage first heat exchange tubes, and the (n - 1)-stage first heat exchange tubes respectively communicate with a plurality of n-stage first heat exchange tubes. Preferably, the diameters of the first heat exchange tubes 121 at each level are the same. The heat exchange fluid is transported from the (n - 1)-stage first heat exchange tube to the n-stage first heat exchange tube. Wherein, N and n are natural numbers, and N > 3, 1 < n ≤ N. The substrate 11 has an inner wall surface 112, and a phase change energy storage layer 13 is provided between the first heat exchange tube 121 and the inner wall surface 112.

[0040] For the battery pack of the present application, a heat exchange tube group including at least four - stage heat exchange tubes is arranged in the substrate 11. The upper - level heat exchange tubes are communicated with a plurality of lower - level heat exchange tubes, thereby creating a multi - branch heat exchange tube group structure in the substrate 11, which can reduce the pressure loss of the heat exchange fluid in the heat exchange tube group, resulting in a smaller pressure drop, helping to save energy consumption and improve the heat exchange efficiency. At the same time, by arranging a phase - change energy - storage layer 13 between the heat exchange tubes and the inner wall surface 112 of the substrate 11, the characteristic that the phase - change energy - storage layer 13 absorbs heat during the phase - change process can be utilized to reduce the battery temperature and improve the temperature uniformity. The combination of the phase - change energy - storage layer 13 and the heat exchange tube group realizes the reduction of the battery temperature. Combining the advantages of both can increase the contact area and distribution uniformity between the heat exchange tubes and the single battery 2, effectively improve the dissipation capacity, be conducive to the uniform and rapid heat transfer to the single battery 2, and the flow of the heat exchange fluid can also reduce the failure of the phase - change energy - storage material 131 after reaching the phase - change temperature.

[0041] The substrate 11 has a first end wall 113 and a second end wall 114 arranged oppositely and a side wall 115 surrounding between the first end wall 113 and the second end wall 114. The side wall 115 is respectively connected to the first end wall 113 and the second end wall 114. The first end wall 113 or the second end wall 114 is arranged oppositely to the single battery 2. In a preferred embodiment, the first - stage first heat exchange tube 1211 is preferably communicated with the outside of the substrate 11 at the side wall 115, that is, the fluid inlet 1157 is preferably arranged on the side wall 115. Such a design can be beneficial for the substrate 11 to be designed smaller, saving materials while also reducing its occupation of the internal space of the battery pack.

[0042] In a preferred embodiment, a second heat exchange tube 141 is further arranged in the accommodation cavity 111, and the second heat exchange tube 141 is communicated with the outside of the substrate 11. Specifically, a fluid outlet 1158 for communicating its outside and the accommodation cavity 111 is arranged on the substrate 11, and the second heat exchange tube 141 is communicated with the fluid outlet 1158. The N - th - stage first heat exchange tube is communicated with the second heat exchange tube 141, and the heat exchange fluid in the N - th - stage first heat exchange tube forms a confluence through the second heat exchange tube and then flows out to the outside of the substrate 11 through the fluid outlet 1158. A phase - change energy - storage layer 13 is arranged between the second heat exchange tube 141 and the inner wall surface 112. In a further preferred embodiment, the second heat exchange tube 141 is communicated with the outside of the substrate 11 at the side wall 115, that is, the fluid outlet 1158 is also preferably arranged on the side wall 115. Such a design can be beneficial for the substrate 11 to be designed smaller, saving materials while also reducing its occupation of the internal space of the battery pack.

[0043] It should be noted that the above is only a preferred solution. In specific implementation, the second heat exchange tube 141 may or may not be provided in the accommodation cavity 111. For example, the Nth-stage first heat exchange tube may be directly connected to the outside of the substrate 11, etc. In the embodiment where the second heat exchange tube 141 is provided, the number of the second heat exchange tubes 141 may be any number. For example, all the Nth-stage first heat exchange tubes may form a confluence through a second heat exchange tube 141 and then flow out through the fluid outlet 1158. Another example is that a second heat exchange tube group 14 may also be provided in the accommodation cavity 111, and the second heat exchange tube group 14 includes a plurality of second heat exchange tubes 141. The plurality of second heat exchange tubes 141 are classified, and the total number of stages of the plurality of second heat exchange tubes 141 is I. The first-stage second heat exchange tube 1411 is connected to the outside of the substrate 11. The number of the (i - 1)th-stage second heat exchange tubes is less than the number of the ith-stage second heat exchange tubes. The (i - 1)th-stage second heat exchange tubes are respectively connected to a plurality of ith-stage second heat exchange tubes. The Ith-stage second heat exchange tube is connected to the Nth-stage first heat exchange tube. The heat exchange fluid is transported from the ith-stage second heat exchange tube to the (i - 1)th-stage second heat exchange tube, where I and i are natural numbers, and I > 1, 1 < i ≤ I.

[0044] In a further preferred embodiment, it is preferred that the Ith-stage second heat exchange tube and the Nth-stage first heat exchange tube are connected in a one-to-one correspondence. The side wall 115 preferably includes a first wall portion 1151, a second wall portion 1152, a third wall portion 1153, and a fourth wall portion 1154 respectively connected to the first end wall 113 and the second end wall 114. One end of the first wall portion 1151 is connected to one end of the second wall portion 1152 to form a first corner portion 1155. One end of the third wall portion 1153 is connected to one end of the fourth wall portion 1154 to form a second corner portion 1156. The first corner portion 1155 and the second corner portion 1156 are diagonally arranged. For example Figures 1 to 3As shown schematically in a preferred embodiment, the substrate 11 has a rectangular plate-like structure. In the accommodation cavity 111, a four-stage first heat exchange tube group 12 and a four-stage second heat exchange tube group 14 are provided, that is, N and I are both 4. The first heat exchange tube group 12 includes a first-stage first heat exchange tube 1211, a second-stage first heat exchange tube 1212, a third-stage first heat exchange tube 1213, and a fourth-stage first heat exchange tube 1214. The second heat exchange tube group 14 includes a first-stage second heat exchange tube 1411, a second-stage second heat exchange tube 1412, a third-stage second heat exchange tube 1413, and a fourth-stage second heat exchange tube 1414. One end of the first-stage first heat exchange tube 1211 communicates with the outside of the substrate 11 at the first corner portion 1155, and the other end extends toward the second corner portion 1156; one end of the first-stage second heat exchange tube 1411 communicates with the outside of the substrate 11 at the second corner portion 1156, and the other end extends toward the first corner portion 1155, that is, the fluid inlet 1157 and the fluid outlet 1158 are arranged diagonally, and the first-stage first heat exchange tube 1211 and the first-stage second heat exchange tube 1411 are arranged to extend along the diagonal direction between the first corner portion 1155 and the second corner portion 1156.

[0045] The first-stage first heat exchange tube 1211 communicates with two second-stage first heat exchange tubes 1212. The two second-stage first heat exchange tubes 1212 are located in the middle of the substrate 11 and on both sides of the diagonal between the first corner portion 1155 and the second corner portion 1156. A part of the tube body of the second-stage first heat exchange tube 1212 is arranged in parallel and spaced from the diagonal between the first corner portion 1155 and the second corner portion 1156, and the other part of the tube body is bent toward the direction close to the diagonal between the first corner portion 1155 and the second corner portion 1156 and then communicates with the first-stage first heat exchange tube 1211.

[0046] The first-stage second heat exchange tube 1411 communicates with two second-stage second heat exchange tubes 1412. The two second-stage second heat exchange tubes 1412 are located on the periphery of the second-stage first heat exchange tube 1212. One end of one second-stage second heat exchange tube 1412 facing away from the first-stage second heat exchange tube 1411 extends towards the direction close to the first wall portion 1151, and one end of the other second-stage second heat exchange tube 1412 facing away from the first-stage second heat exchange tube 1411 extends towards the direction close to the second wall portion 1152. Each second-stage first heat exchange tube 1212 communicates with three third-stage first heat exchange tubes 1213 respectively. The three third-stage first heat exchange tubes 1213 are spaced apart along the diagonal direction between the first corner portion 1155 and the second corner portion 1156. One end of the third-stage first heat exchange tube 1213 facing away from the second-stage first heat exchange tube 1212 extends towards the direction close to the second-stage second heat exchange tube 1412 on the same side. Each second-stage second heat exchange tube 1412 communicates with three third-stage second heat exchange tubes 1413 spaced apart along the extending direction of the second-stage second heat exchange tube 1412 respectively. One end of the third-stage second heat exchange tube 1413 facing away from the second-stage second heat exchange tube 1412 extends towards the direction close to the second-stage first heat exchange tube 1212 on the same side. Each third-stage first heat exchange tube 1213 communicates with two fourth-stage first heat exchange tubes 1214 respectively, and each third-stage second heat exchange tube 1413 communicates with two fourth-stage second heat exchange tubes 1414 respectively. The fourth-stage first heat exchange tubes 1214 and the fourth-stage second heat exchange tubes 1414 on the same side of the diagonal between the first corner portion 1155 and the second corner portion 1156 are in one-to-one correspondence and communicate with each other. With such a design, the heat exchange tubes can be laid more widely in the accommodation cavity 111 of the substrate 11, and the heat exchange efficiency of the heat management device 1 can be improved. Of course, the above is only a preferred solution. In other embodiments, the first-stage second heat exchange tube and the N-stage first heat exchange tube may not be in one-to-one correspondence and communication, that is, the first-stage second heat exchange tube may communicate with multiple N-stage first heat exchange tubes, or some of the first-stage second heat exchange tubes communicate with some of the N-stage first heat exchange tubes in one-to-one correspondence, while the other part of the first-stage second heat exchange tubes communicate with multiple N-stage first heat exchange tubes, etc. The communication mode between the N-stage first heat exchange tube and the first-stage second heat exchange tube is not limited in this embodiment and can be designed according to specific needs. In addition, in other embodiments, the number of stages of the first heat exchange tubes 121 in the first heat exchange tube group 12 is not limited to four, and may also be five, six or more stages. The n-stage first heat exchange tube is preferably located between the second-stage first heat exchange tube 1212 and the second-stage second heat exchange tube 1412, where n > 2; the number of stages of the second heat exchange tubes 141 in the second heat exchange tube group 14 is not limited to four, and may also be two, three, five or more stages. The i-stage second heat exchange tube is preferably located between the second-stage first heat exchange tube 1212 and the second-stage second heat exchange tube 1412, where i > 2.In addition, the substrate 11 can also be a plate-like structure of other shapes. For example, in other embodiments, the substrate 11 can also be a plate-like structure of other polygons such as a triangle, a pentagon, etc., or a plate-like structure of other quadrilaterals such as a parallelogram. Additionally, in other embodiments, the fluid inlet 1157 or the fluid outlet 1158 can also be provided at other non-corner positions on the side wall 115.

[0047] In a preferred embodiment, the nth-stage first heat exchange tube is inclined with respect to the flow direction of the heat exchange fluid in the (n - 1)th-stage first heat exchange tube, and the inclination angle is an acute angle, preferably 35° - 60°. This inclination angle can be any value among 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, 55°, 56°, 57°, 58°, 59°, 60° or the range between any two values. Designed in this way, the resistance of the heat exchange tube group to the heat exchange fluid can be reduced, which helps to reduce the pressure loss of the heat exchange fluid in the heat exchange tube group and lower the pressure drop. Similarly, in the embodiment where the second heat exchange tube group 14 is provided, the ith-stage second heat exchange tube is also preferably inclined with respect to the flow direction of the heat exchange fluid in the (i - 1)th-stage second heat exchange tube, and the inclination angle is an obtuse angle, preferably 120° - 145°. This inclination angle can be any value among 120°, 121°, 122°, 123°, 124°, 125°, 126°, 127°, 128°, 129°, 130°, 131°, 132°, 133°, 134°, 135°, 136°, 137°, 138°, 139°, 140°, 141°, 142°, 143°, 144°, 145° or the range between any two values.

[0048] In a preferred embodiment, the phase change energy storage layer 13 preferably includes a phase change energy storage material 131 and a porous carrier 132. The phase change energy storage material 131 includes an inorganic phase change material, an organic phase change material, and a composite phase change material. The phase change temperature range of the phase change energy storage material 131 is preferably between 35°C and 45°C. The phase change energy storage material 131 preferably adopts an organic phase change material such as paraffin, polyol, and fatty acid, or an inorganic phase change material such as sodium acetate trihydrate and sodium thiosulfate pentahydrate. The porous carrier 132 preferably adopts expanded graphite or porous alumina, etc. After the phase change energy storage material 131 is attached to the porous carrier 132, it is filled between the first heat exchange tube 121 and the inner wall surface 112. By providing the porous carrier 132, the phase change energy storage material 131 can be better restricted, so that the phase change energy storage material 131 can be more stably maintained at the corresponding position during phase change. At the same time, the porous carrier 132 can also improve the thermal conductivity and enhance the heat exchange efficiency of the heat management device 1.

[0049] In a preferred embodiment, the substrate 11 is preferably made of a metal or metal alloy with high thermal conductivity, such as aluminum, copper, aluminum alloy, copper alloy, etc.

[0050] In a preferred embodiment, the heat exchange fluid is preferably a coolant fluid with high specific heat capacity such as water, ethylene glycol, or a mixture thereof.

[0051] In order to describe the technical solution more clearly, the following Figure 5 The first direction Z and the second direction X are perpendicular to each other. The first direction Z corresponds to the axial direction of the single cell 2, and the second direction X corresponds to the radial direction of the single cell 2. A pole 21 is provided at one end of the single cell 2 along the first direction Z. In this embodiment, taking a square battery as an example, the second direction X is also the direction of the large wall surface 22 of the single cell 2. In other embodiments where the single cell 2 is a cylindrical battery, the second direction X is also the radial direction of the cylindrical battery.

[0052] In one embodiment, the thermal management device 1 may be disposed on one side of the single battery 2 in the second direction X. Figures 5 to 8 As shown in , the battery pack includes a plurality of square batteries distributed along the second direction X, the thermal management device 1 is arranged between adjacent square batteries, and the first end wall 113 and the second end wall 114 of the substrate 11 face the large wall surfaces 22 of the two square batteries respectively.

[0053] In another embodiment, the thermal management device 1 may also be arranged on the end side of the single battery 2 away from the pole 21, for example Figure 9 and Figure 10 As shown in FIG. 1 , the first end wall 113 or the second end wall 114 of the base plate 11 faces the single battery 2 .

[0054] In a further preferred embodiment, a connection layer 3 is preferably provided between the thermal management device 1 and the single battery 2. The connection layer 3 may be a thermally conductive adhesive layer, or a layer of a material having heat insulation and compressibility such as aerogel or glass fiber. A thermally conductive adhesive layer is preferably used, which can reduce the interface thermal resistance between the single battery 2 and the thermal management device 1.

[0055] The above description is only a partial implementation method of the embodiments of the present application and does not constitute any form of limitation on the application. The protection scope of the embodiments of the present application is not limited thereto. Any simple modifications, equivalent changes and modifications that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the embodiments of the present application should be covered within the protection scope of the embodiments of the present application.

Claims

1. A battery pack, characterized in that: The battery pack comprises a thermal management device (1) and a single battery (2), wherein the thermal management device (1) is attached to the outer wall of the single battery (2). The thermal management device (1) comprises a substrate (11), wherein a receiving cavity (111) is arranged in the substrate (11), wherein a first heat exchange tube group (12) is arranged in the receiving cavity (111), wherein the first heat exchange tube group (12) comprises a plurality of first heat exchange tubes (121), wherein the plurality of first heat exchange tubes (121) are graded, wherein the total number of the plurality of first heat exchange tubes (121) is N, wherein the first heat exchange tube (1211) of the first stage is connected to the outside of the substrate (11), wherein the number of the first heat exchange tubes of the n-1 stage is less than the number of the first heat exchange tubes of the n-1 stage, wherein the first heat exchange tube of the n-1 stage is respectively connected to the plurality of first heat exchange tubes of the n-1 stage, and wherein the heat exchange fluid is transported from the first heat exchange tube of the n-1 stage to the first heat exchange tube of the n-1 stage; wherein the first heat exchange tube (121) of the first stage is provided with a phase change energy storage layer (13) between the first heat exchange tube (121) and the inner wall surface (112), Where N and n are natural numbers, and N>3,1 <n≤N。 2. The battery pack according to claim 1, characterized in that: The n-th stage first heat exchange tube is arranged to be inclined relative to the flow direction of the heat exchange fluid in the n-1-th stage first heat exchange tube, and the inclination angle is an acute angle.

3. The battery pack according to claim 1, characterized in that: A second heat exchange tube (141) is also provided in the accommodating cavity (111); the second heat exchange tube (141) is connected to the outside of the substrate (11); the Nth-stage first heat exchange tube is connected to the second heat exchange tube (141); and a phase change energy storage layer (13) is provided between the second heat exchange tube (141) and the inner wall surface (112).

4. The battery pack according to claim 1, characterized in that: A second heat exchange tube group (14) is also arranged in the accommodating cavity (111), the second heat exchange tube group (14) comprising a plurality of second heat exchange tubes (141), the plurality of second heat exchange tubes (141) are graded, the total number of the plurality of second heat exchange tubes (141) is I, the first-stage second heat exchange tube (1411) is connected to the outside of the substrate (11), the number of the second heat exchange tubes of the i-1 stage is less than the number of the second heat exchange tubes of the i-1 stage, the second heat exchange tubes of the i-1 stage are respectively connected to a plurality of the second heat exchange tubes of the i-1 stage, the second heat exchange tubes of the i-1 stage are connected to the first heat exchange tubes of the N-1 stage, and the heat exchange fluid is transported from the second heat exchange tube of the i-1 stage to the second heat exchange tube of the i-1 stage. Where I and i are natural numbers, and I>1,1 <i≤I。 5. The battery pack according to claim 4, characterized in that: The second heat exchange tube of the Ith stage is connected to the first heat exchange tube of the Nth stage in a one-to-one correspondence.

6. The battery pack according to claim 1, characterized in that: The substrate (11) comprises a first end wall (113) and a second end wall (114) which are arranged opposite to each other, and a side wall (115) which is arranged between the first end wall (113) and the second end wall (114); the side wall (115) is connected to the first end wall (113) and the second end wall (114), respectively; and the first-stage first heat exchange tube (1211) is connected to the outside of the substrate (11) at the side wall (115).

7. The battery pack according to claim 3, characterized in that: The substrate (11) comprises a first end wall (113) and a second end wall (114) which are arranged opposite to each other, and a side wall (115) which is arranged between the first end wall (113) and the second end wall (114); the side wall (115) is connected to the first end wall (113) and the second end wall (114) respectively; and the second heat exchange tube (141) is connected to the outside of the substrate (11) at the side wall (115).

8. The battery pack according to claim 3, characterized in that: The substrate (11) comprises a first end wall (113) and a second end wall (114) which are arranged opposite to each other, and a side wall (115) which is arranged between the first end wall (113) and the second end wall (114); the side wall (115) comprises a first wall portion (1151), a second wall portion (1152), a third wall portion (1153) and a fourth wall portion (1154) which are respectively connected to the first end wall (113) and the second end wall (114); one end of the first wall portion (1151) is connected to the second wall portion (1152) ) are connected to form a first corner portion (1155), one end of the third wall portion (1153) is connected to one end of the fourth wall portion (1154) to form a second corner portion (1156), the first corner portion (1155) and the second corner portion (1156) are arranged diagonally, the first stage first heat exchange tube (1211) is connected to the outside of the substrate (11) at the first corner portion (1155), and the second heat exchange tube (141) is connected to the outside of the substrate (11) at the second corner portion (1156).

9. The battery pack according to claim 4, characterized in that: The second-stage first heat exchange tube (1212) is located in the middle of the substrate (11), the second-stage second heat exchange tube (1412) of the second heat exchange tube group (14) is located outside the second-stage first heat exchange tube (1212), and the nth-stage first heat exchange tube is located between the second-stage first heat exchange tube (1212) and the second-stage second heat exchange tube (1412). Among them, n>2.

10. The battery pack according to claim 1, characterized in that: The single cell (2) has a first direction (Z) and a second direction (X) arranged vertically, and a pole (21) is arranged at one end of the single cell (2) along the first direction (Z); The thermal management device (1) is arranged on the end side of the single battery (2) facing away from the pole (21); or The heat management device (1) is arranged on one side of the single battery (2) in the second direction (X).

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