Battery packs and electrical equipment

Abstract

The present application discloses a battery pack and an electrical device, belonging to the field of battery technology. The battery pack includes: a single cell; a thermal management component, the thermal management component is in contact with the single cell, and the contact area is S; the thermal management component includes a liquid cooling part and a heat conduction part, the liquid cooling part and the single cell are spaced apart, and the distance between the liquid cooling part and the single cell is d; the heat conduction part is filled between the liquid cooling part and the single cell; the battery pack satisfies: #imgabs0#, where α is a design constant; the unit of S is m 2 ; d is in m; W is the heating power of the single cell, in w; γ is the thermal conductivity of the heat conducting part, in W / mK; δ is the correction factor, when δ is 3×10 5 When α is designed, it satisfies 1≤α≤300. Since the battery pack satisfies the above relationship, it effectively avoids the overflow of the thermal management component performance of the battery pack, which means that both performance and cost are taken into consideration, achieving a better balance between the performance and cost of the entire battery pack.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a battery pack and electrical equipment. Background Art

[0002] With the development of battery systems, liquid cooling solutions have become the mainstream technical solution for battery packs. The performance and cost of thermal management components are also key factors that restrict the overall performance and cost of the entire system. Since the liquid cooling solution sets up a corresponding liquid cooling plate to contact the battery for heat dissipation, the contact area between the liquid cooling plate and the battery will affect the heat dissipation efficiency of the entire battery pack. When the heat dissipation area is increased, the mass and volume of the liquid cooling plate will also increase, which may cause the energy density of the battery pack to decrease. In addition, for some battery packs with lower heat generation power, adding more liquid cooling plates will cause performance overflow and a decrease in the battery pack energy density, and also increase costs. Therefore, how to achieve the relationship between battery pack energy density, heat dissipation effect and cost has become a difficult problem that needs to be overcome. Summary of the Invention

[0003] Purpose of the invention: An embodiment of the present application provides a battery pack, aiming to resolve the conflicting relationship between the energy density, heat dissipation requirements and cost of the liquid cooling system and the battery pack in the prior art; another purpose of the embodiment of the present application is to provide an electrical device.

[0004] Technical solution: The battery pack described in the embodiment of the present application includes:

[0005] Multiple single cells;

[0006] Thermal management components,

[0007] The thermal management component includes a liquid cooling part and a heat conducting part. The liquid cooling part and the single battery are spaced apart, and the minimum distance between the liquid cooling part and the single battery is dm. The heat conducting part is arranged between the liquid cooling part and the single battery and connects the single battery and the liquid cooling part, and the contact area between the heat conducting part and the plurality of single batteries is Sm. 2 The thermal conductivity of the heat conducting portion is γW / mK; the heating power of the single cell is Ww;

[0008] The battery pack satisfies the following relationship:

[0009]

[0010] Among them, α is the design constant; δ is the correction coefficient, δ = 3 × 10 5 , the design constant α satisfies 1≤α≤300.

[0011] In some embodiments, the maximum charge rate of the battery pack is η, and the battery pack satisfies the following relationship:

[0012] 0.001C≤η / α≤1.5C.

[0013] In some embodiments, when the maximum charge rate η of the battery pack satisfies: 0.3C≤η<1.5C, the design constant α satisfies: 1≤α≤20;

[0014] When the maximum charging rate η satisfies: 1.5C≤η<8C, the design constant α satisfies 20<α≤300.

[0015] In some embodiments, the discharge rate of the battery pack is The battery pack satisfies the following relationship:

[0016]

[0017] In some embodiments, when the discharge rate of the battery pack is satisfy: The design constant α satisfies: 20≤α≤100;

[0018] When the discharge rate of the battery pack satisfy: For the battery pack, the design constant α satisfies: 1.5≤α<20.

[0019] In some embodiments, the battery pack satisfies: 0.5≤S≤6, preferably 1≤S≤4.

[0020] In some embodiments, the battery pack satisfies: 6000≤W≤20000, preferably 10000≤W≤16000.

[0021] In some embodiments, the battery pack satisfies: 0.1≤γ≤3.5, preferably 1≤γ≤2.

[0022] In some embodiments, the battery pack satisfies: 0.0008≤d≤0.003, preferably 0.001≤d≤0.002.

[0023] In some embodiments, the battery cell includes a top cover, a bottom wall, and four side walls connected between the top cover and the bottom wall, and the thermal management component is connected to at least one of the bottom wall, at least one of the side walls, and the top cover.

[0024] In some embodiments, the design constant α satisfies: 1≤α≤20, the thermal management component is connected to the bottom wall, the area of the bottom wall is S', and satisfies: 0.85≤S / S'≤1.

[0025] In other embodiments, the design constant α satisfies: 20<α≤300, and the thermal management component is connected to at least two of the bottom wall, at least one of the side walls, and the top cover.

[0026] In other embodiments, the design constant α satisfies: 20<α≤300, and the thermal management component is connected to at least two of the four side walls.

[0027] In some embodiments, there are multiple liquid cooling parts, each of which extends along a first direction, and the multiple liquid cooling parts are arranged at intervals along the second direction, and the first direction intersects the second direction; at least one single battery is arranged between two adjacent liquid cooling parts, and the design constant α satisfies: 20<α≤300.

[0028] Accordingly, an electrical device described in an embodiment of the present application includes the battery described in any of the above embodiments.

[0029] Beneficial effect: Compared with the existing technology, this solution comprehensively considers the contact area between the liquid cooling assembly and the single battery, the thermal conductivity of the heat conducting part, the distance between the liquid cooling part and the single battery and the heating power of the single battery, and when the battery pack satisfies the relationship When the heat dissipation effect is balanced, the energy density of the battery pack can be balanced with the heat dissipation effect and cost. In the battery pack, the performance of the thermal management component can be adapted to the heat generation power of the single cell, ensuring the effectiveness of the thermal management of the battery pack and thus improving the performance of the battery pack. In addition, in the battery pack, the distance d between the single cell and the liquid cooling part, the thermal conductivity γ of the heat-conducting part, the contact area S between the thermal management component and the single cell, and the heat generation power W of the single cell are interrelated and matched. When the heat generation power of the single cell has been determined, the various parameters can be reasonably adjusted according to their mutual relationship, effectively avoiding the performance of the thermal management component of the battery pack not meeting the requirements or performance overflow, that is, taking into account both performance and cost, and achieving a better balance between the performance and cost of the entire battery pack.

[0030] Compared with the prior art, the electric device of the embodiment of the present application includes the above-mentioned battery pack. The electric device can have all the technical features and corresponding beneficial effects of the above-mentioned battery pack, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a schematic structural diagram of the battery pack according to the first embodiment of the present application from a first angle;

[0033] Figure 2 This is a schematic structural diagram of the battery pack according to the first embodiment of the present application from a second angle;

[0034] Figure 3 yes Figure 2 Schematic diagram of the local enlarged structure of area A in the middle;

[0035] Figure 4 yes Figure 1 Schematic diagram of the exploded structure of the battery pack parts; reference numerals: 100 - single cell; 101 - top cover; 102 - side wall; 200 - thermal management component; 210 - liquid cooling unit; 220 - heat conduction unit. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0037] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships 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 cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined.

[0038] It should also be noted that in the embodiments of the application, "parallel" refers to the state where the angle formed by a straight line, a straight line and a plane, or a plane and a plane is -1° to 1°. Furthermore, "perpendicular" refers to the state where the angle formed by a straight line, a straight line and a plane, or a plane and a plane is 89° to 91°. Equal distances refer to the state where the tolerance range is -1% to 1%.

[0039] The applicant noted that existing liquid cooling solutions employ liquid cooling plates that contact the battery for heat dissipation. This contact area affects the heat dissipation efficiency of the entire battery pack. Increasing the heat dissipation area also increases the mass and volume of the liquid cooling plates, potentially reducing the energy density of the battery pack. Furthermore, for battery packs with lower heat dissipation, adding more liquid cooling plates can lead to performance degradation, a decrease in battery pack energy density, and increased costs. Therefore, achieving a balance between battery pack energy density, heat dissipation, and cost remains a challenging issue.

[0040] In view of this, embodiments of the present application provide a battery pack to overcome at least one of the above-mentioned technical problems.

[0041] Please also refer to Figures 1 to 3 , Figure 1 The first angle structure of the battery pack of the first embodiment of the present application is illustrated. Figure 2 The second angle structure of the battery pack of the first embodiment of the present application is illustrated. Figure 3 Indicated Figure 2 A partial magnified structure of area A. In the first embodiment, the battery pack includes a plurality of stacked single cells 100 and a thermal management assembly 200 . The thermal management assembly 200 is in contact with the single cells 100 to cool the single cells 100 .

[0042] In the embodiment of the present application, the thermal management assembly 200 includes a liquid cooling portion 210 and a heat conducting portion 220. The liquid cooling portion 210 and the single battery 100 are spaced apart, and the minimum spacing between the liquid cooling portion 210 and the single battery 100 is dm; the heat conducting portion 220 is disposed between the liquid cooling portion 210 and the single battery 100 and connects the single battery 100 and the liquid cooling portion 210, and the contact area between the heat conducting portion 220 and the multiple battery cells is Sm. 2 In this embodiment, the heat conducting portion 220 is filled between the liquid cooling portion 210 and the single battery 100. In other words, the single battery 100 is in contact with the heat conducting portion 220 to achieve contact between the single battery 100 and the thermal management component 200. The contact area between the multiple single batteries 100 and the heat conducting portion 220 is the contact area Sm with the thermal management component 200. 2 It should be understood that the contact area Sm 2 = is the sum of the contact areas between the thermal management assembly 200 and each battery cell 100. The thermal conductivity of the heat conducting portion 220 is γW / mK; the heat generation power of the battery cell 100 is Ww.

[0043] The battery pack in this embodiment satisfies the following relationship:

[0044]

[0045] Wherein, α is the design constant; δ is the correction coefficient. In this embodiment, δ = 3×10 5 , the design constant α satisfies 1≤α≤300. In this embodiment, the correction coefficient δ is only used to facilitate the order of magnitude optimization of the value of the relationship. When it takes different values, the value of α may change accordingly.

[0046] That is, the relationship between the contact area S between the thermal management assembly 200 and the plurality of battery cells 100, the heat generation power W of the battery cells 100, the thermal conductivity γ of the heat conducting portion 220, and the distance d between the liquid cooling portion 210 and the battery cells 100 satisfies the following equation:

[0047]

[0048] It can be understood that because the battery pack satisfies the above relationship, the performance of the thermal management assembly 200 in the battery pack is compatible with the individual cells 100, ensuring the effectiveness of the battery pack's thermal management, thereby improving the battery pack's performance. When the value of α is greater than 300, the performance of the thermal management assembly 200 in the battery pack is excessive. In other words, the heat dissipation performance of the thermal management assembly 200 exceeds the heat dissipation requirements of the battery pack, resulting in an overdesign of the thermal management assembly 200 in the battery pack. This causes the thermal management assembly 200 to occupy excessive space and weight in the battery pack, reducing the battery pack's energy density. When the value of α is less than 1, the performance of the thermal management assembly 200 in the battery pack is insufficient. In other words, the heat dissipation performance of the thermal management assembly 200 is less than the heat dissipation requirements of the battery pack, resulting in an underdesign of the thermal management assembly 200. This prevents the thermal management assembly 200 from dissipating heat generated by the battery pack during use, resulting in excessively high temperatures and insufficient safety performance. When the value of α is between 1 and 300, a balance between the energy density and safety requirements of the battery pack is achieved.

[0049] In addition, in this battery pack, the distance d between the single cell 100 and the liquid cooling part 210, the thermal conductivity γ of the heat conducting part 220, the contact area S between the thermal management component 200 and the single cell 100, and the heating power W of the single cell 100 are interrelated and matched. During the actual design and manufacture of the battery pack, each parameter can be reasonably adjusted according to their mutual relationship, effectively avoiding the performance overflow of the thermal management component 200 of the battery pack, or the performance not meeting the cooling requirements, thereby taking into account the battery pack performance and ensuring that the battery pack has a suitable cost, thereby achieving a better balance between the performance and cost of the entire battery pack.

[0050] In this embodiment, the heating power W is the heating power curve of the single battery 100 measured under the condition of maximum discharge current or charge current under adiabatic working conditions, and the maximum value of the heating power curve is taken; or, in other embodiments, the heating power W of the single battery 100 is I 2×R, I is the maximum charge current or maximum discharge current of the single battery 100, in A; R is the internal resistance of the single battery 100, in Ω.

[0051] In this embodiment, the contact area S can be measured by the following method: draw a line along the edge of the contact position between the heat conducting portion 220 and a single battery 100 to mark the contact surface between the single battery 100 and the heat conducting portion 220, measure the side length parameter of this contact surface, calculate the area of this contact surface, and multiply this area by the number of single batteries 100 to obtain the contact area Sm. 2 Or the above steps are performed on the remaining multiple single cells 100, and the contact area of each single cell 100 and the heat conducting portion 220 is obtained, and finally the sum is added to obtain the contact area Sm 2 .

[0052] In this embodiment, the thermal conductivity γW / mK can be measured by a laser flash method or a steady-state heat flow method.

[0053] In this embodiment, the minimum distance dm can be measured by the following method: remove the heat conducting portion 220 and use a vernier caliper or micrometer to measure the thickness of the heat conducting portion 220 in the direction from the liquid cooling portion 210 to the single battery cell 100. Repeat this measurement three or more times and calculate the average of the three smallest values. This average value can be used as the minimum distance dm.

[0054] It should be noted that, in the embodiments of this application, It can be understood that for different types of battery packs, there is a design constant α with the best thermal management performance in the battery pack. This design constant α is inversely proportional to the distance dm between the single battery 100 and the thermal management component 200, and is inversely proportional to the contact area Sm. 2 , the thermal conductivity γW / mK of the heat conducting portion 220, and the heat generation power Ww of the battery cell 100. Thus, the thermal management performance of the battery pack is correlated with the heat generation power of the battery cells 100 in the battery pack. Different thermal management performances can be designed based on the different heat generation power of the battery pack to meet actual needs. This avoids problems such as reduced battery pack energy density due to excessive thermal management performance or safety issues caused by insufficient thermal management performance.

[0055] The purpose of introducing the correction coefficient δ is to avoid the problem that the range of α values is too large due to the large data between different designs, which is not convenient for practical application. 5 , the design constant α satisfies 1≤α≤300, which can ensure that the thermal management component 200 meets the performance requirements and does not have the risk of over-design due to performance overflow.

[0056] It is understood that the value of the correction coefficient δ is not limited to 3×10 5, the value of the correction coefficient δ can be selected as needed. After determining the specific value of the correction coefficient δ, the range of the design constant α can be determined according to conventional mathematical operations. Assuming that δ' is the actual correction coefficient used and α' is the actual design constant used, then Knowing that the value of α ranges from 1 to 300, the range of the design constant α' used in practice can be determined.

[0057] Furthermore, in some embodiments, the maximum charge rate of the battery pack is η, and the battery pack satisfies the following relationship:

[0058] 0.001C≤η / α≤1.5C,

[0059] The charge rate is a measure of charging speed. It refers to the current required to charge a battery to its rated capacity in a specified time. It is numerically equal to a multiple of the battery's rated capacity: "Charging current / rated battery capacity = charge rate." For example, if a battery has a capacity of 100A and a charging current of 100A, the charge rate is 1C. If a 100A battery is consistently charged at a 1C charge rate, it can theoretically be fully charged in one hour. The charge rate affects the heat generated by the battery pack. Generally speaking, the higher the maximum charge rate, the greater the heat dissipation requirements of the battery pack, and the higher the required heat dissipation performance of the thermal management assembly 200. When the value of the above equation is greater than 1.5, the maximum charge rate η is too high compared to the heat dissipation performance of the thermal management assembly, and the thermal management assembly's heat dissipation requirements cannot meet the battery's maximum charge rate requirements. When the value of the above equation is less than 0.001, the thermal management assembly's heat dissipation performance is too high compared to the maximum charge rate η, resulting in a decrease in the battery pack's energy density and an increase in manufacturing costs.

[0060] In this embodiment, based on the relationship between the maximum charge rate η of the battery pack and the design constant α, the value of the design constant α can be further determined after the maximum charge rate η is determined. The design constant α can then be used to further adjust the distance dm between the single battery 100 and the liquid cooling unit 210, the thermal conductivity γW / mK of the heat conducting unit 220, and the contact area Sm between the thermal management assembly 200 and the single battery 100. 2 Adjustments are made so that the heat dissipation performance of the thermal management component 200 can meet the charging performance requirements of the battery pack, avoiding overflow or deficiency of the performance of the thermal management component 200.

[0061] In this embodiment, η / α can be any value of 0.0001C, 0.0003C, 0.005C, 0.010C, 0.015C, 0.020C, 0.025C, 0.030C, 0.035C, 0.040C, 0.045C, 0.050C, 0.055C, 0.060C, 0.065C, 0.070C, 0.075C, 0.080C, 0.085C, 0.090C, 0.095C, 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 0.6C, 0.7C, 0.8C, 0.9C, 1.0C, 1.1C, 1.2C, 1.3C, 1.4C, and 1.5C, or a range between any two values. Within this range, the battery pack can be designed for fast charging and slow charging, meeting the needs of most battery pack applications.

[0062] Furthermore, when the maximum charge rate η of the battery pack satisfies: 0.3C ≤ η ≤ 1.5C, the design constant α is selected to satisfy 1 ≤ α ≤ 20. That is, the design constant α can be any value among 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or a range between any two values. Within this range, the heat dissipation performance requirements of a battery pack with a conventional charge rate are not high. Therefore, when the spacing dm is determined, the contact area Sm between the heat conducting portion 220 and the multiple single batteries 100 can be appropriately reduced. 2 , the thermal conductivity of the heat-conducting portion 220 is γW / mK, so as to reduce the manufacturing cost of the thermal management component 200 and meet the heat dissipation requirements of the battery pack at the same time.

[0063] Furthermore, when the charge rate η of the battery pack satisfies: 1.5C ≤ η ≤ 8C, the design constant α is selected to satisfy 20 < α ≤ 300. That is, the design constant α can be any value among 21, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, or a range between any two values. Within this range, fast-charging battery packs have higher requirements for heat dissipation performance. Therefore, after the spacing dm is determined, the contact area S m between the heat conducting portion 220 and the multiple single battery cells 100 can be appropriately increased. 2 , the thermal conductivity coefficient of the heat-conducting portion 220 is γW / mK, so as to improve the heat dissipation efficiency of the thermal management component 200 and ensure the safety of the battery pack during use.

[0064] Furthermore, in some embodiments, the battery pack satisfies:

[0065]

[0066] in, The maximum discharge rate of the battery pack. The discharge rate is a measure of discharge speed. It refers to the current intensity required for the battery to discharge its rated capacity within a specified time. Its numerical value is equal to a multiple of the battery's rated capacity, that is, "discharge current / battery rated capacity = discharge rate." For example, if a battery with a rated capacity of 100A is discharged at 20A, its discharge rate is 0.2C.

[0067] In this embodiment, according to the maximum discharge rate of the battery pack The relationship with the design constant α can be determined after the discharge rate is determined. Under the premise of , the value of the design constant α is determined, and then the design constant α value is used to further calculate the distance dm between the single battery 100 and the liquid cooling part 210, the thermal conductivity γW / mK of the heat conducting part 220, and the contact area Sm between the thermal management component 200 and the single battery 100. 2 Adjustments are made so that the heat dissipation performance of the thermal management assembly 200 matches the discharge rate of the battery pack.

[0068] In this embodiment, It can be any value among 0.08C, 0.09C, 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 0.6C, 0.7C, 0.8C, 0.9C, 1.0C, 5.0C, 10C, 15C, 20C, 25C, 30C, 35C, 40C, 45C, 50C, 55C, 60C, 65C, 70C or any range between any two values. When the above formula is greater than 70, the discharge rate Compared with the design constant α, the heat dissipation performance of the thermal management component 200 is not enough to take away the heat of the battery pack in time, which makes the temperature of the battery pack too high during use, affecting the safety of the battery pack. When the value of the above formula is less than 0.08, the design constant α is larger than the discharge rate. Large, that is, the performance of the thermal management component 200 is already too redundant, which will lead to a waste of battery pack manufacturing costs; therefore, when It can take into account both the heat dissipation requirements and manufacturing costs of the battery pack.

[0069] Furthermore, in some embodiments, for the discharge rate for For a battery pack, the design constant α is selected to satisfy 20≤α≤100. That is, the design constant α can be any value among 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, or a range between any two values. Within this range, the heat dissipation requirement of the battery pack is high, so the contact area Sm between the single battery 100 and the heat conducting portion 220 is appropriately increased. 2 , the thermal conductivity coefficient γW / mK of the heat-conducting portion 220, or reducing the distance dm between the liquid cooling portion 210 and the single battery 100 to increase the design constant α and meet the heat dissipation requirements of the battery pack.

[0070] Furthermore, in other embodiments, for the discharge rate satisfy: In this case, the design constant α is selected to be 1.5≤α<20. That is, the design constant α can be any value among 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or a range between any two values. Within this range, the heat dissipation requirement of the battery pack is high, so the contact area Sm between the single battery 100 and the heat conducting portion 220 is appropriately increased. 2 , the thermal conductivity coefficient γW / mK of the heat-conducting portion 220, or reducing the distance dm between the liquid cooling portion 210 and the single battery 100 to increase the design constant α and meet the heat dissipation requirements of the battery pack.

[0071] In some embodiments, the battery pack satisfies: 0.5≤S≤6. That is, the contact area Sm between the thermal management component 200 and the plurality of battery cells 100 is 2 0.5m 2 ~6m 2 , where it can be understood that the contact area Sm 2 The sum of the areas of the liquid cooling unit 210 and each battery cell 100 connected through the heat conducting unit 220, for example, S can be any value among 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 or a range between any two values. 2 More than 6m 2 When the contact area Sm is less than 0.05, the surface area of the liquid cooling portion 210 will be larger accordingly. At this time, the volume and weight of the entire thermal management component 200 will increase accordingly, which will greatly affect the energy density of the battery pack. 2 Less than 0.5m 2When the temperature is too low, the surface area of the liquid cooling unit 210 will be reduced accordingly. At this point, the battery pack's most basic heat dissipation requirements cannot be met, which will seriously affect the thermal management safety of the battery pack. Therefore, in this embodiment, 0.5≤S≤6 can balance the energy density and thermal management safety performance of the battery pack; more preferably, 1≤S≤4.

[0072] In some embodiments, the battery pack satisfies the following: 6000≤W≤20000. That is, the heat generation power Ww of the single cell 100 is 6000w-20000w. For example, W can be any value among 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, or a range between any two values. When the heat generation power Ww of the single cell 100 is greater than 20000w, the thermal management level of the battery pack is too high. However, due to the range limitation of α, the contact area Sm of the thermal management component 200 is too large. 2 The smaller the range of values for the thermal conductivity γW / mK, the less likely it is that the performance of the thermal management assembly 200 will meet the heating power requirements of the single cell 100. Furthermore, the higher the heating power, the lower the energy utilization of the battery pack, resulting in significant energy waste. When the heating power Ww of the single cell 100 is less than 6000W, the performance of the battery pack in low-temperature conditions will be affected, and even rapid power loss may occur. Therefore, in this embodiment, 6000 ≤ W ≤ 20000 is selected to balance the low-temperature performance of the battery pack with the thermal management requirements and energy utilization. Preferably, 10000 ≤ W ≤ 16000 is selected.

[0073] In some embodiments, the battery pack satisfies the following: 0.1 ≤ γ ≤ 3.5. That is, the thermal conductivity γ W / mK of the heat conducting portion 220 is 0.1 W / mK to 3.5 W / mK. For example, γ can be any value among 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, or a range between any two values. When designing the battery pack, selecting the heat conducting portion 220 within this range helps ensure the accuracy of the design parameters and facilitates the accurate selection of the cooling equipment. When the thermal conductivity γW / mK of the heat-conducting portion 220 is greater than 3.5W / mK, the material price of the heat-conducting portion 220 will increase accordingly, thereby significantly increasing the overall manufacturing cost of the battery pack; when the thermal conductivity γW / mK of the heat-conducting portion 220 is less than 0.1W / mK, the thermal conductivity of the heat-conducting portion 220 is too low, and the heat of the single battery 100 cannot be effectively transferred to the liquid cooling portion 210 in a timely manner. 2 Even if the value is large enough, it will not meet the heat dissipation requirements of the battery pack, and will waste space and weight of the battery pack, affecting the energy density of the battery pack. Therefore, in this embodiment, 0.1≤γ≤3.5 can take into account the manufacturing cost of the battery pack as well as the heat dissipation requirements and energy density; more preferably, 1≤γ≤2.

[0074] In some embodiments, the battery pack satisfies the following: 0.0008≤d≤0.003. That is, the distance dm between the liquid cooling unit 210 and the battery cell 100 is 0.0008m to 0.002m. It is understood that the heat conducting portion 220 is filled between the liquid cooling unit 210 and the battery cell 100. Therefore, the distance dm is also the thickness of the heat conducting portion 220 along the spacing direction between the liquid cooling unit 210 and the battery cell 100. For example, d can be any value selected from 0.0008, 0.0009, 0.001, 0.0011, 0.0012, 0.0013, 0.0014, 0.0015, 0.0016, 0.0017, 0.0018, 0.0019, 0.002, 0.0025, and 0.003, or a range between any two values. When the distance dm between the liquid cooling section 210 and the battery cell 100 is greater than 0.002 m, the heat transfer distance between the battery cell 100 and the liquid cooling section 210 is too large, resulting in a corresponding decrease in heat transfer efficiency. Furthermore, the thickness of the heat conducting section 220 is too large, occupying excessive space in the battery pack and reducing the energy density of the battery pack. When the distance dm between the liquid cooling section 210 and the battery cell 100 is less than 0.0008 m, the thickness of the heat conducting section 220 is too small. Since the heat conducting section 220 generally also needs to connect the liquid cooling section 210 and the battery cell 100, the heat conducting section 220 generally adheres to the liquid cooling section 210 and the battery cell 100. Therefore, the thickness of the heat conducting section 220 affects the connection strength between the liquid cooling section 210 and the battery cell 100. If the thickness of the heat conducting section 220 is too small, the bonding strength is correspondingly low, and the mounting strength between the liquid cooling section 210 and the battery cell 100 is too weak, resulting in a low overall structural strength of the battery pack and reduced safety performance. In this embodiment, 0.0008≤d≤0.002 is preferred to ensure both the thermal conductivity and structural connection performance of the heat conducting portion 220. More preferably, 0.001≤d≤0.002 is preferred. In some embodiments, the single cells 100 of the battery pack can be pouch cells, prismatic cells, cylindrical cells, etc., without limitation herein.

[0075] In particular, see Figure 4 , Figure 4 Indicated Figure 1The exploded structure of the battery pack components; in the first embodiment, the single battery cell 100 is square and includes a top cover 101, a bottom wall, and four side walls 102 connected between the top cover 101 and the bottom wall. The thermal management assembly 200 is connected to at least one of the bottom wall, at least one side wall 102, and the top cover 101. In other words, the thermal management assembly 200 can dissipate heat from the battery pack by contacting the bottom wall, by contacting one or more side walls 102, by contacting the top cover, or by contacting the bottom wall, side walls 102, and the top cover simultaneously. The number of walls that the thermal management assembly 200 contacts can be determined based on specific design parameters.

[0076] In some embodiments, the design constant α satisfies: 1≤α≤20, at which point the thermal management component 200 is connected to the bottom wall, wherein the area of the bottom wall is S', and satisfies 0.8≤S / S'≤1. That is, when the bottom wall and the thermal management component 200 are in contact, S' is the area of the bottom wall; for example, S / S' can be any value among 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 0.1, or a range between any two values. Within this range, on the one hand, the uniformity of cooling can be ensured, and on the other hand, it is helpful for reference in selecting the liquid cooling unit 210, which is conducive to accurate selection. When the value of S / S' is less than 0.8, only the heat conducting portion 220 contacts a portion of the bottom wall of the single cell 100. Due to the presence of the heat conducting portion 220, the distance between the liquid cooling portion 210 and the single cell 100 is determined by the thickness of the heat conducting portion 220. If the area of contact between the heat conducting portion 220 and the bottom wall of the single cell 100 is less than 0.8, the distance between the liquid cooling portion 210 and the single cell 100 will not be fully utilized, thereby wasting space in the battery pack.

[0077] In another embodiment, the design constant α satisfies: 20<α≤300. In this case, the heat dissipation requirement of the battery pack is relatively large, and the thermal management component 200 is connected to at least two of the bottom wall, at least one side wall 102 and the top cover 101 to meet the requirement of increasing the contact area S.

[0078] Alternatively, in other embodiments, the design constant α satisfies: 20 < α ≤ 300, and the thermal management assembly 200 is connected to at least two of the four sidewalls 102. In this case, the liquid cooling unit 210 is connected only to the sidewalls 102 of the battery cell 100, simplifying the structure of the thermal management assembly while meeting the contact area S requirement.

[0079] In this embodiment, there are multiple liquid cooling parts 210, and the liquid cooling parts 210 extend along the first direction (i.e., the length direction of the single cell 100). The multiple liquid cooling parts 210 are arranged at intervals along the second direction (i.e., the thickness direction of the single cell). At least one single cell 100 is arranged between two adjacent liquid cooling parts 210, and the design constant α satisfies: 20<α≤300.

[0080] In some embodiments, the liquid cooling portion 210 is a harmonica tube, that is, a plurality of flow channels for the circulation of liquid cooling medium are opened in the liquid cooling portion 210 , and the harmonica tube is connected to the single battery 100 through the heat conducting portion 220 .

[0081] Accordingly, embodiments of the present application further provide an electrical device comprising the aforementioned battery pack. The electrical device may be an electric vehicle (EV), a hybrid electric vehicle (HEV), a range-extended electric vehicle (REEV), or a plug-in hybrid electric vehicle (PHEV). It is understood that the electrical device may have all the technical features and corresponding beneficial effects of the aforementioned battery pack, which will not be further elaborated herein.

[0082] Next, specific embodiments of the battery pack of the present application are provided, and the present application is described in more detail through specific embodiments. It can be seen from the following embodiments that, in actual implementation, when the battery pack satisfies the relationship of the present application, the heat dissipation effect and energy density of the battery pack can be in an optimal state at the same time.

[0083] Example 1: EV-Pack solution design. This EV-Pack product uses ordinary lithium iron phosphate material, with a maximum charge rate η of 0.7C and a maximum discharge rate The heat dissipation requirement of this material system is not high. A conventional structural adhesive with a thermal conductivity coefficient γW / mK of 0.2W / mK is selected as the heat conducting part 220. The actual heating power Ww of the single battery 100 is about 6000w through experimental measurement. The distance d between the single battery 100 and the liquid cooling part 210 is 0.002. The contact area Sm between the thermal management component 200 and the single battery 100 is 2 0.53m 2In this case, the thermal management assembly 200 is connected to the bottom wall of the single cell 100, and the calculated design constant α is 1.06. At this point, the battery pack has an energy density of 140Wh / kg, and the heat dissipation effect (i.e., the performance of the thermal management assembly 200) is 0.3°C / min. The heat dissipation efficiency is measured under pure cooling conditions. In this embodiment, heat dissipation efficiency / energy density = 0.0021, meaning the heat dissipation efficiency per unit energy density is 0.0021°C / min. With this design, the battery pack achieves balanced performance across all aspects.

[0084] Example 2: EV-Pack solution design. The EV-Pack product supports fast charging function, that is, η is greater than 1.5. In this embodiment, the maximum charging rate η is 4C and the maximum discharge rate is The temperature is 10C, and ternary lithium materials are generally used. At this time, the heat dissipation demand is relatively large. A thermal conductive structural adhesive with a thermal conductivity coefficient γW / mK of 2W / mK is selected as the heat conducting part 220. The actual heating power Ww of the single battery 100 is about 18000w through experimental measurement. The distance dm between the single battery 100 and the liquid cooling part 210 is 0.0016m. The contact area Sm between the thermal management component 200 and the single battery 100 is 2 4.0m 2 At this point, the thermal management assembly 200 is connected to the bottom wall and three side walls 102 of the single battery cell 100. The calculated design constant α is 300. At this point, the battery pack has an energy density of 170Wh / kg and a heat dissipation efficiency of 0.8°C / min. This heat dissipation efficiency is measured under pure cooling conditions. In this embodiment, heat dissipation efficiency / energy density = 0.0047, meaning that the heat dissipation efficiency per unit energy density is 0.0047°C / min. With this design, the battery pack achieves balanced performance across all aspects.

[0085] Example 3: EV-Pack design, also supports fast charging function, with a maximum charge rate η of 2.2C and a maximum discharge rate The thermal conductivity is 8C, and a thermal conductive structural adhesive with a thermal conductivity coefficient γW / mK of 1.2W / mK is used as the heat conducting part 220. The actual heating power Ww of the single battery 100 is about 12000w through experimental measurement; the distance dm between the single battery 100 and the liquid cooling part 210 is 0.002m; the contact area Sm between the thermal management component 200 and the single battery 100 is 2 1.2m 2At this point, the thermal management assembly 200 is connected to both sidewalls 102 of the single cell 100. The calculated design constant α is 28.8. At this point, the battery pack has an energy density of 180Wh / kg and a heat dissipation efficiency of 0.7°C / min. This heat dissipation value is measured under pure cooling conditions. In this embodiment, heat dissipation efficiency / energy density = 0.0038, meaning the heat dissipation efficiency per unit energy density is 0.0038°C / min. This design achieves balanced performance across the battery pack.

[0086] Example 4: HEV-Pack design, maximum charge rate η is 1C, maximum discharge rate The temperature is 20°C, and a heat-conducting structural adhesive with a thermal conductivity coefficient γW / mK of 0.7W / mK is used as the heat-conducting part 220. The actual heating power Ww of the single battery 100 is about 8000W through experimental measurement; the distance dm between the single battery 100 and the liquid cooling part 210 is 0.002m; the contact area Sm between the thermal management component 200 and the single battery 100 is 2 0.5m 2 At this point, the thermal management assembly 200 is connected to the bottom wall of the single cell 100. The calculated design constant α is 4.66. At this point, the battery pack has an energy density of 145Wh / kg and a heat dissipation efficiency of 0.3°C / min. The heat dissipation value is measured under pure cooling conditions. In this embodiment, heat dissipation efficiency / energy density = 0.0020, meaning the heat dissipation efficiency per unit energy density is 0.0020°C / min. With this design, the battery pack achieves balanced performance across all aspects.

[0087] Examples 5-6 all use the same LFP material and the same spacing d as Example 1. The differences are the contact area S, thermal conductivity γ, and heating power. It can be seen that as the heating power W increases, the heat dissipation area S increases synchronously, and ultimately, the energy density and heat dissipation efficiency of each battery pack can be roughly equivalent. The heat dissipation performance (heat dissipation efficiency / energy density) is near the reference value of Example 1. At this time, the design constant α satisfies: 1≤α≤300.

[0088] Examples 7-15 all use ternary lithium materials, wherein:

[0089] Examples 7-9 have different heating powers Ww and contact areas Sm 2 , the spacing dm is the same, and by changing the thermal conductivity γW / mK, the energy density and heat dissipation efficiency of the three battery packs are finally made roughly equivalent, and the heat dissipation performance (heat dissipation efficiency / energy density) is near the reference value of Example 3. At this time, the design constant α satisfies: 1≤α≤300.

[0090] The heating power of Examples 10-12 is different, and the contact area Sm 2, and thermal conductivity γW / mK are the same. By changing the spacing dm, the energy density and heat dissipation efficiency of the three battery packs are ultimately made roughly equivalent. The heat dissipation performance (heat dissipation efficiency / energy density) is near the reference value of Example 2, and the design constant α satisfies: 1≤α≤300.

[0091] The heating power, thermal conductivity γW / mK and spacing dm of Examples 13-15 are the same, and the contact area Sm is changed. 2 , ultimately making the energy density and heat dissipation efficiency of the three battery packs roughly equivalent, and the design constant α satisfies: 1≤α≤300.

[0092] Comparative Example 1 and Comparative Example 2 are comparative examples of Example 4 and Example 5. It can be seen that when the thermal conductivity γW / mK, spacing dm, and heating power Ww are the same, reducing the contact area Sm 2 , and the design constant is made less than 1, which ultimately leads to a decrease in energy density and heat dissipation effect, and the value of heat dissipation effect / energy density is also much smaller than that of Example 4 and Example 5, indicating that the heat dissipation performance of the thermal management component 200 is insufficient.

[0093] Comparative Examples 3 and 4 are comparative examples of Examples 13-15. It can be seen that when the thermal conductivity γW / mK, spacing dm, and heating power Ww are the same, increasing the contact area Sm 2 , and makes the design constant greater than 300, which ultimately leads to a decrease in energy density, and the value of heat dissipation effect / energy density is also much greater than the values of Examples 13-15, indicating that the heat dissipation performance of the thermal management component 200 overflows, and the cost will be greatly wasted at this time.

[0094] In Examples 16-19, it can be seen that the contact area Sm 2 When any of the values of γW / mK, thermal conductivity, spacing dm, and heating power Ww is out of the preferred range, the heat dissipation performance and energy density cannot be well balanced.

[0095] Examples 1 to 19 are shown in the following table:

[0096]

[0097]

[0098] Comparative Examples 1 to 4 are shown in the following table:

[0099]

[0100] It can be seen from the above embodiments and comparative examples that when the design constant α is less than 1, the value of the heat dissipation efficiency / energy density is much smaller than the value of the heat dissipation efficiency / energy density in Examples 4-6, which means that the heat dissipation performance of the battery pack is not sufficient to support the energy density of the battery pack; when the design constant α is greater than 300, the value of the heat dissipation efficiency / energy density is much larger than the value of the heat dissipation efficiency / energy density in Examples 7-15, which means that the heat dissipation performance of the battery pack has exceeded the energy density of the battery pack, which will cause unnecessary cost waste.

[0101] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0102] The above is a detailed introduction to the battery pack and electrical equipment provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery pack, characterized in that: include: a plurality of single cells (100); A thermal management component (200) includes a liquid cooling portion (210) and a heat conducting portion (220), wherein a flow channel for circulating a liquid cooling medium is provided in the liquid cooling portion (210), the liquid cooling portion (210) and the single battery (100) are arranged at intervals, and the minimum distance between the liquid cooling portion (210) and the single battery (100) is dm; the heat conducting portion (220) is arranged between the liquid cooling portion (210) and the single battery (100) and connects the single battery (100) and the liquid cooling portion (210), and the heat conducting portion (220) contacts a plurality of the single batteries (100), and the contact area is Sm 2 The thermal conductivity of the heat conducting portion (220) is γW / mK; the heating power of the single battery (100) is Ww; The battery pack satisfies the following relationship: Where α is the design constant; δ is the correction coefficient, δ=3×10 5 , the design constant α satisfies 1≤α≤300; Moreover, 0.5≤S≤6, 6000≤W≤20000, 0.1≤γ≤3.5, 0.0008≤d≤0.

003.

2. The battery pack according to claim 1, characterized in that: The maximum charging rate of the battery pack is η, and the battery pack satisfies the following relationship: 0.001C≤η / α≤1.5C.

3. The battery pack according to claim 2, characterized in that: When the maximum charge rate η of the battery pack satisfies: 0.3C≤η<1.5C, the design constant α satisfies: 1≤α≤20; When the maximum charging rate η satisfies: 1.5C≤η<8C, the design constant α satisfies: 20<α≤300.

4. The battery pack according to claim 1, wherein: The maximum discharge rate of the battery pack is The battery pack satisfies the following relationship:

5. The battery pack according to claim 4, characterized in that: When the maximum discharge rate of the battery pack satisfy: The design constant α satisfies 20≤α≤100; When the maximum discharge rate of the battery pack satisfy: The design constant α satisfies 1.5≤α<20.

6. The battery pack according to claim 1, characterized in that: The battery pack satisfies: 1≤S≤4, 10000≤W≤16000, 1≤γ≤2, 0.001≤d≤0.

002.

7. The battery pack according to claim 1, characterized in that: The single battery (100) comprises a top cover (101), a bottom wall, and four side walls (102) connected between the top cover (101) and the bottom wall; the thermal management component (200) is connected to at least one of the bottom wall, at least one of the side walls (102), and the top cover (101).

8. The battery pack according to claim 7, characterized in that: The battery pack meets one of the following three conditions: i) the design constant α satisfies: 1≤α≤20, the thermal management component (200) is connected to the bottom wall, the area of the bottom wall is S', and satisfies: 0.8≤S / S'≤1; ii) the design constant α satisfies: 20<α≤300, and the thermal management component (200) is connected to at least two of the bottom wall, at least one of the side walls (102), and the top cover (101); iii) The design constant α satisfies: 20<α≤300, and the thermal management component (200) is connected to at least two of the four side walls (102).

9. The battery pack according to claim 1, characterized in that: There are a plurality of liquid cooling parts (210), each of which extends along a first direction, and the plurality of liquid cooling parts (210) are arranged at intervals along a second direction, wherein the first direction intersects the second direction; at least one single battery (100) is arranged between two adjacent liquid cooling parts (210), and the design constant α satisfies: 20<α≤300.

10. An electrical device, characterized in that: A battery pack comprising the battery pack according to any one of claims 1 to 9.

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