Battery assembly and electric device

Abstract

Provided in the embodiments of the present application are a battery assembly and an electric device. In the battery assembly provided in the embodiments of the present application, a parameter relationship between a battery cell and a heat-absorbing member is defined, such that the designed thickness of the heat-absorbing member can be optimized while achieving a relatively good thermal diffusion suppression effect, thereby reducing the production costs of the battery assembly and ensuring a relatively high energy density of the battery assembly.

Description

Battery assembly and electric device

[0001] The present application claims priority to the Chinese patent application No. 202410844035.7, filed on June 26, 2024, and entitled "Battery assembly and electric device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, in particular to a battery assembly and an electric device. BACKGROUND

[0003] In the electric device with high energy consumption demand and the energy storage system, the battery assembly generally includes a plurality of single batteries arranged in series or in parallel. Although the safety performance of the single battery is relatively high at present, the occurrence of extreme working conditions (for example, violent impact, etc.) may cause one or more single batteries in the battery assembly to have thermal runaway. At this time, it is extremely important to inhibit the spread of heat emitted by the runaway single battery in the battery assembly. Therefore, it is urgent to provide a battery assembly design scheme for inhibiting heat diffusion. SUMMARY

[0004] In view of this, the present application embodiments provide a battery assembly and an electric device. The battery assembly provided by the present application embodiments defines the parameter relationship between the single battery and the heat absorption member, can optimize the design thickness of the heat absorption member while taking into account the relatively optimal heat diffusion inhibition effect, reduce the production cost of the battery assembly, and ensure that the energy density is relatively high.

[0005] The first aspect of the present application embodiments provides a battery assembly, comprising:

[0006] a plurality of single batteries, the plurality of single batteries are arranged along a first direction, and each single battery includes a shell and an electric core accommodated in the shell;

[0007] a heat absorption member, the heat absorption member is arranged between at least part of adjacent single batteries, the heat absorption member has a heat absorption main material, the heat absorption main material is adapted to absorb heat generated by the single battery; on a side of the single battery close to the heat absorption member, there is a gap between the electric core and the shell;

[0008] wherein the size of the heat absorption main material in the first direction is δ PCM m;

[0009] the size of the electric core in the first direction is δ c m;

[0010] the size of the gap in the first direction is δ g m;

[0011] The volume density of the heat absorption main material is p kg / m 3 ;

[0012] The heat absorption amount of the heat absorption main material per unit mass from 25°C to the process of completing the phase change of the heat absorption main material is H J / kg;

[0013] The battery assembly satisfies:

[0014] 0.7≤δ PCM / (((-1.823×10 5 )+(2.467×10 8 )δ c +(-5.576×10 8 )δ g +(-3.491×10 10 )δ c δ g ) / ρH)≤1.3.

[0015] When one or several single batteries are in thermal runaway, the battery assembly has a small risk of thermal spread and high thermal safety performance, and has a high energy density.

[0016] In some embodiments of the present application, 5×10 -3 ≤δ c ≤60×10 -3 .

[0017] In some embodiments of the present application, 0.2×10 -3 ≤δ g ≤2×10 -3 .

[0018] In some embodiments of the present application, p≥500.

[0019] In some embodiments of the present application, H≥5×10 5 .

[0020] In some embodiments of the present application, the heat absorption main material comprises a framework and a heat absorption material carried on the framework, and the thickness of the heat absorption material in a first direction is greater than or equal to the thickness of the framework in the first direction.

[0021] In some embodiments of the present application, the framework has a hole, and the heat absorption material is filled in the hole.

[0022] In some embodiments of the present application, the heat absorption member further comprises a packaging member, and the heat absorption main material is accommodated in the packaging member.

[0023] In some embodiments of the present application, the monomer battery is a square monomer battery, and the heat absorption member is arranged close to a large surface of the monomer battery.

[0024] The second aspect of the embodiments of the present application provides a power consumption device including the battery assembly provided by the first aspect of the embodiments of the present application. Since the battery assembly provided by the first aspect of the embodiments of the present application is used to supply power for the power consumption device, the power consumption device has strong endurance and strong market competitiveness. BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a schematic structural diagram of a battery assembly provided by an embodiment of the present application;

[0026] FIG. 2 is a schematic structural diagram of a monomer battery in the battery assembly provided by an embodiment of the present application;

[0027] FIG. 3 is a schematic structural diagram of a power consumption device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0028] The embodiments of the present application provide a battery assembly. Please refer to FIG. 1. The battery assembly includes a plurality of monomer batteries arranged along a first direction and a heat absorption member between at least some adjacent monomer batteries. The heat absorption member has a heat absorption main material, and the heat absorption main material is adapted to absorb heat generated by the monomer batteries. The monomer battery includes a shell and a battery cell accommodated in the shell. There is a gap between the battery cell and the shell on the side of the monomer battery close to the heat absorption member. In the embodiments of the present application, the shell can be a commonly used shell for accommodating the battery cell in the field, for example, an aluminum plastic shell, and the thickness of the shell is not limited, and the commonly used thickness in the field can be used. It should be noted that FIG. 1 is only an example of drawing, and the number, relative position and size of the monomer batteries and the heat absorption member in FIG. 1 do not limit the embodiments of the present application. In addition, the monomer battery includes a side, a top and a bottom, wherein the side connects the top and the bottom. In addition, the surface of the monomer battery can be provided with a positive pole and a negative pole exposed outside the shell (not shown in the figure); it should be noted that the embodiments of the present application do not limit whether the above-mentioned poles are provided and the position of the poles, and the person skilled in the art can select according to the actual situation, for example: the poles can be arranged on the top, bottom or side of the monomer battery.

[0029] The size of the heat absorption main material in the first direction is δ PCM m;

[0030] The size of the battery cell in the first direction is δ c m;

[0031] The size of the gap in the first direction is δ g m;

[0032] The volume density of the heat absorption main material is ρ kg / m 3 ;

[0033] The heat absorption amount of the heat absorption main material per unit mass during the process of increasing temperature from 25℃ to the completion of the phase change of the heat absorption main material is H J / kg;

[0034] The battery assembly satisfies:

[0035] 0.7≤δ PCM / (((-1.823×10 5 )+(2.467×10 8 )δ c +(-5.576×10 8 )δ g +(-3.491×10 10 )δ c δ g ) / ρH)≤1.3.

[0036] For convenience of description, hereinafter, ((-1.823×10 5 )+(2.467×10 8 )δ c +(-5.576×10 8 )δ g +(-3.491×10 10 )δ c δ g ) / ρH) is denoted as Formula 1.

[0037] The size of the heat absorption main material in the first direction is δ PCM m; in the embodiments of the present application, the size of the heat absorption main material in the first direction can be measured by using a micrometer, specifically, the size of the heat absorption main material in the first direction is measured at 10 optional points on each heat absorption main material and the arithmetic mean value is taken as the size of the heat absorption main material in the first direction. In some embodiments of the present application, the heat absorption main material is a heat absorption material; for example, it can be a sheet-shaped heat absorption material. In other embodiments of the present application, the heat absorption main material comprises a skeleton and a heat absorption material carried on the skeleton, and the size of the heat absorption material in the first direction is greater than or equal to the size of the skeleton in the first direction. In this way, the waste of the internal space of the battery assembly can be avoided, and the volume energy density of the battery assembly can be ensured to be high. In some embodiments of the present application, the heat absorption member further comprises an encapsulation member, and the heat absorption main material is accommodated in the encapsulation member. It can be understood that the thickness of the encapsulation member is not included in δ PCM . In the embodiments of the present application, the encapsulation member can be selected from the commonly used encapsulation members of heat absorption members in the art, for example, an aluminum film, an aluminum plastic film, a polyethylene terephthalate (PET) film, etc., and the thickness of the encapsulation member can be the commonly selected thickness in the art.

[0038] The dimension of the cell in the first direction is δ c m; in the embodiments of the present application, the cell can be before formation, after formation, after capacity grading, or after cycling. It should be noted that the dimension δ c of the cell in the first direction should be measured when the state of charge of the cell is less than 5% SOC. In addition, since the cell is working in the battery assembly, it is necessary to test the above δ c under the condition of applying pressure. Specifically: discharge the cell to a state of charge <5% SOC, disassemble the monomer battery, place it on the test platform, and make the first surface of the cell (the first surface and the second surface are the opposite surfaces of the cell in the first direction, and the surface should be the surface adjacent to the heat sink) face the test platform, place a steel plate on the second surface of the cell (the steel plate covers the second surface), and the steel plate applies pressure to the cell, the pressure F = 10 5 Pa x A, A is the area of the second surface, unit: m 2 ; then use laser to test the distance from the four corners of the steel plate in contact with the second surface of the cell to the test platform, δ c , which is the arithmetic mean of the four distance values measured above.

[0039] The dimension of the gap in the first direction is δ g m; it should be noted that the dimension δ g of the gap is the gap dimension between the shell of the monomer battery in the battery assembly and the cell, and not the dimension measured when the monomer battery is freely placed. The above gap refers to the gap distance between the shell on the side of the monomer battery close to the heat sink and the surface of the cell opposite to it. Specifically, the test of the dimension δ g of the above gap includes: test the sum of the dimensions of all monomer batteries (number n) in the battery assembly in the first direction, denoted as δ t m, then δ g = (δ t -n x δ c -2n x δ k ) / 2n, δ g , δ t , δ k and δ c are in the same unit, and δ k is the thickness of the shell in the first direction.

[0040] The bulk density of the heat-absorbing main material is ρ kg / m 3;In the embodiments of the present application, the drainage method is used to test the bulk density of the heat-absorbing main material. Specifically, when the heat-absorbing main material is a sheet-shaped heat-absorbing material, the bulk density of the heat-absorbing material is tested; when the heat-absorbing main material includes a skeleton and heat-absorbing material carried on the skeleton, at this time, the comprehensive density of the heat-absorbing material and the skeleton is tested, specifically: the mass of the heat-absorbing material is m1 kg, the bulk density is p1 kg / m 3 , the mass of the skeleton is m2 kg, the bulk density is p2 kg / m 3 , and then the bulk density p of the heat-absorbing main material is (m1+m2) / (m1 / p1+m2 / p2).

[0041] The heat-absorbing amount of the unit mass of the heat-absorbing main material from 25°C to the completion of the phase change of the heat-absorbing main material is H J / kg. In the embodiments of the present application, the Differential Scanning Calorimetry (DSC) method is used to test the H of the heat-absorbing main material. In the embodiments of the present application, the completion of the phase change refers to the state when the temperature of the heat-absorbing main material exceeds the phase change temperature by 10°C. Specifically, first, the mass percentage of the heat-absorbing material relative to the heat-absorbing main material is denoted as a, and the mass percentage of the skeleton relative to the heat-absorbing main material is denoted as b. First, the phase change temperature of the heat-absorbing material and the heat-absorbing amount H a of the heat-absorbing material from 25°C to the completion of the phase change are determined or calculated using DSC. Then, the heat change H b of the material of the skeleton from 25°C to the completion of the phase change of the heat-absorbing material is determined using DSC (H b can be greater than 0, less than 0, or equal to 0), and H = a x H a + b x H b . In the embodiments of the present application, the heating rate during the DSC test is 10°C / min, and the test atmosphere is air.

[0042] It can be understood that the heat-absorbing member arranged between the single batteries not only can quickly absorb heat under the condition of thermal runaway of the single battery, but also can play a certain heat-absorbing / heat-dissipating role during the normal charging and discharging of the single battery, which is beneficial to the constant working temperature of the battery assembly. In extreme working conditions, when the single battery is in thermal runaway, the larger the volume of the same battery system, the greater the heat release. The size of the heat-absorbing member in the extension direction of the battery can be the same as that of the single battery, so the thickness of the heat-absorbing member, or the thickness of the heat-absorbing material in the heat-absorbing member, is crucial, and generally increases with the increase of the thickness of the battery (i.e., d c ). However, the applicant found that the gap size (d g ) between the shell of the single battery and the battery also cannot be ignored, and it is negatively correlated with the thickness (d PCM ) of the heat-absorbing main material in the first direction, and more importantly, dc and δ g The influence of the amount of heat-absorbing material has an interaction, and specifically the product of δ g and δ c is negatively correlated with δ PCM .

[0043] In addition, when the bulk density of the heat-absorbing material is greater, the heat-absorbing amount of the heat-absorbing material per unit volume is greater, and as the bulk density increases, the adaptability of reducing the thickness of the heat-absorbing main material is greater, and H is also more conducive to improving the heat-absorbing amount of the heat-absorbing material per unit volume. According to the formula 1 provided in the embodiments of the present application, δ PCM can be quickly determined, and when the heat-absorbing member and the related art heat-absorbing member achieve the same heat spread suppression effect, the thickness of the heat-absorbing main material can be sufficiently reduced, the cost is saved, and the energy density of the battery assembly is improved. In other words, under the same cost or the same energy density, a more optimal heat spread suppression effect is achieved, and it has guiding significance for the selection of the heat-absorbing member in the battery assembly and the production and assembly of the battery assembly: during the production process, engineers only need to determine δ c , δ g , and the related parameters ρ, H of the selected heat-absorbing main material, and then δ PCM can be quickly determined through the formula (1) provided in the embodiments of the present application.

[0044] In some embodiments of the present application, the morphology and size of the plurality of single batteries in the battery assembly are consistent. In other embodiments, the morphology and size of the plurality of single batteries in the battery assembly can be different, and at this time, when the heat-absorbing member is provided with single batteries on the opposite two sides in the first direction, the parameters of the single batteries on the opposite two sides and δ PCM both need to satisfy formula 1 respectively. It should be noted that FIG. 2 is only an example drawing, and the size, relative position of the battery and the shell, and other parameters in FIG. 2 do not limit the embodiments of the present application.

[0045] In some embodiments of the present application, the heat absorption member can be arranged between any two adjacent single batteries in the battery assembly. The single batteries and the heat absorption members are arranged alternately in the first direction, and thus the thickness direction of the single battery is parallel to the first direction. In this way, the heat spreading between any two single batteries can be inhibited in extreme working conditions, thereby more effectively reducing the thermal safety performance of the battery assembly in extreme working conditions. In the first direction, the heat absorption member can be arranged near the end surface of the battery assembly, or the single battery can be arranged near the end surface of the battery assembly. For example, the single battery is denoted as X, and the heat absorption member is denoted as Y. In the first direction, the battery assembly can include XYXY...Y, YXYX...Y, XYXYX...X, or YXYX...X. However, the present application is not limited thereto. For example, in some cases, the skilled in the art selects to arrange the heat absorption member between part of the adjacent two single batteries, so that the heat absorption member and the adjacent single battery satisfy formula (1), or the heat absorption member is not arranged between the remaining part of the adjacent two single batteries, or other phase change materials are arranged between the remaining part of the adjacent two single batteries.

[0046] It can be understood that, taking a square battery as an example, the thickness direction of the square battery is perpendicular to the large face (i.e., the side face with the largest area) of the square battery. When the square battery is in thermal runaway, it mainly expands in the thickness direction. Therefore, in some embodiments of the present application, when the single battery is a square battery, the heat absorption member is arranged near the large face of the single battery. In some specific embodiments, the heat absorption member is in contact with the large face of the single battery. In this way, the heat absorption member can fully absorb the heat emitted by the single battery during the normal charging and discharging cycle and the thermal runaway process, and more effectively inhibit the spreading of heat in the battery assembly, thereby improving the thermal safety performance of the battery assembly, and without occupying too much internal space of the battery assembly, which has a high cost performance. In the embodiments of the present application, the square battery includes a single battery whose size in the extension direction is much larger than its thickness direction, and the projection shape of the square battery in the first direction is not limited. The projection shape of the square battery in the first direction can be any shape, such as a rectangle, a quadrilateral, a pentagon, a hexagon, etc., such as a blade battery, etc. In the embodiments of the present application, the orthographic projection shape of the heat absorption member in the first direction can be adapted to the shape of the single battery. In addition, the size of the heat absorption member in the first direction can be determined according to the single battery, for example, the orthographic projection of the heat absorption member in the first direction overlaps or approximately overlaps with the orthographic projection of the single battery in the first direction.

[0047] In some embodiments of the present application, 5×10 -3 ≤δ c ≤60×10 -3 That is, the size of the battery cell in the first direction is 5 mm-60 mm. Specifically, the above δ c For example, it can be 5×10-3 , 10x10 -3 , 15x10 -3 , 20x10 -3 , 25x10 -3 , 30x10 -3 , 35x10 -3 , 40x10 -3 , 45x10 -3 , 50x10 -3 , 55x10 -3 , 60x10 -3 , etc. Controlling the dimension of the cell in the first direction within the above range is both industrially easy to obtain and beneficial to the heat release amount of the cell itself in the thermal runaway state, and thus is beneficial to improving the thermal safety performance of the battery assembly. In some embodiments, 5x10 -3 ≤ δ c ≤ 40x10 -3 .

[0048] It can be understood that, for a liquid monomer battery using a liquid electrolyte, the gap between the cell and the shell generally also accommodates electrolyte. Considering that δ g and the thickness of the heat-absorbing material are negatively correlated, and the cell size δ c and the gap size δ g between the cell and the shell have an interaction on the effect of the heat spread suppression of the battery assembly, and the accommodation amount of the electrolyte, in some embodiments of the present application, 0.1x10 -3 ≤ δ g ≤ 2x10 -3 , that is, the gap size between the shell and the cell of the monomer battery in the first direction is 0.1mm-2mm. In this way, it is more beneficial to balance the performance of the monomer battery and the thermal safety performance and energy density of the final battery assembly. Specifically, the above δ g may be, for example, 0.1x10 -3 , 0.2x10 -3 , 0.5x10 -3 , 0.8x10 -3 , 1.0x10 -3 , 1.2x10 -3 , 1.5x10 -3 , 1.8x10 -3 , 2.0x10 -3 , etc. In some embodiments, 0.2x10 -3 ≤ δ g ≤ 1x10 -3 .

[0049] In some embodiments of the present application, the heat-absorbing main component is a sheet-shaped heat-absorbing material, which includes but is not limited to a composite material of a phase change material and a matrix, such as a composite material of heat-absorbing particles and a heat-insulating matrix, a mechanical reinforcing material, etc. In some other embodiments, the heat-absorbing main component includes a skeleton and heat-absorbing material carried on the skeleton, and the heat-absorbing material includes but is not limited to a material containing a liquid phase change medium. In this way, the heat-absorbing effect can be achieved by the phase change of the liquid phase change medium, and the heat-absorbing main component has a certain compression resistance. The liquid phase change medium includes at least one of water, ethanol, ethylene glycol, etc. The composite material can be a composite material of a hydrogel or a hydrated salt and other materials (such as a flame retardant), etc. Taking the hydrogel as an example, a high molecular material with a network structure can be used as the matrix of the hydrogel, and water can be used as the liquid phase change medium. In the embodiments of the present application, the material of the skeleton includes but is not limited to polypropylene (PP), polyethylene terephthalate (PET), glass fiber, metal, etc., and the present application does not limit the same.

[0050] In some embodiments of the present application, the skeleton includes a plurality of holes, and the holes are filled with the heat-absorbing material. In some specific embodiments, the skeleton has a plurality of holes penetrating through the skeleton along the thickness direction (i.e., the first direction) of the skeleton, and the holes are filled with the heat-absorbing material, and the thickness of the heat-absorbing material is greater than or equal to the thickness of the skeleton. In this way, the skeleton not only gives the heat-absorbing component a higher compression resistance, but also plays a role in carrying the heat-absorbing material and shaping the heat-absorbing component, and the heat-absorbing effect is better. The embodiments of the present application do not limit the shape of the holes of the skeleton. The shape of the holes can be triangular, quadrangular, pentagonal, hexagonal (such as honeycomb), trapezoidal, etc. In the embodiments of the present application, the arrangement mode and size of the holes in the skeleton are not limited, and a person skilled in the art can select them according to the actual production needs, and the design structure of the skeleton commonly used in the art can be used.

[0051] In some embodiments of the present application, ρ≥500. The heat-absorbing main component with the above-mentioned bulk density is easy to obtain, and the heat-absorbing effect is better. Specifically, the bulk density of the heat-absorbing main component can be, for example, 500 kg / m 3 , 550 kg / m 3 , 600 kg / m 3 , 650 kg / m 3 , 700 kg / m 3 , 750 kg / m 3 , 800 kg / m 3 , 850 kg / m 3 , 900 kg / m 3 , 950 kg / m 3 , 1000 kg / m 3 , 1100 kg / m 3 , 1200 kg / m 3 , 1300 kg / m3 , 1400 kg / m 3 , 1500 kg / m 3 , etc.

[0052] In some embodiments of the present application, H≥5×10 5 ; that is, the heat absorption amount of the heat absorption main material per unit mass during the process of increasing the temperature from 25°C to the completion of the phase change of the heat absorption main material is≥5×10 5 J / kg. The heat absorption main material with the above H is easy to obtain in industry and has good heat absorption effect. Specifically, the H of the heat absorption main material may, for example, be 5×10 5 , 6×10 5 , 7×10 5 , 8×10 5 , 9×10 5 , 10×10 5 , 11×10 5 , 12×10 5 , 13×10 5 , 14×10 5 , 15×10 5 , 16×10 5 , etc. In some specific embodiments, H≥12×10 5 .

[0053] In some embodiments of the present application, the battery cell includes a positive electrode, the positive electrode includes a positive electrode current collector and a positive electrode material layer arranged on at least one side surface of the positive electrode current collector, and the positive electrode material layer includes modified or unmodified lithium iron phosphate. The thermal safety performance of the lithium iron phosphate battery is relatively better, and when the lithium iron phosphate battery satisfies formula 1 defined in the embodiments of the present application, the risk of thermal spread is smaller under the same working conditions and battery component parameters.

[0054] In the embodiments of the present application, the battery component can be a battery module or a battery pack. In the above battery component, a plurality of single batteries can be connected in series, in parallel, or in a combination thereof to form a battery pack.

[0055] Please refer to FIG. 3, the embodiments of the present application also provide a power consumption device including the battery component provided by the embodiments of the present application. Since the power consumption device is powered by the battery component provided by the embodiments of the present application, the power consumption device has strong market competitiveness.

[0056] In some embodiments of the present application, the power consumption device includes, but is not limited to, a vehicle, a mobile phone, a notebook computer, a tablet computer, and other 3C electronic products, a station energy backup power system, and a smart photovoltaic power station.

[0057] The technical solutions of the present application are further described in the following embodiments.

[0058] Embodiment 1

[0059] A battery assembly is designed, which comprises five identical lithium iron phosphate single batteries and four identical heat absorption members, and the lithium iron phosphate single batteries and the heat absorption members are arranged alternately along a first direction, and any adjacent single battery is separated by a heat absorption member; wherein, δ PCM is the size of the heat absorption material in the first direction;

[0060] δ c of the single battery is 0.012, δ g of the heat absorption member is 0.0005, ρ of the heat absorption member is 1400, and H is 1.6×10 6 , δ PCM is 0.8×10 -3 .

[0061] Example 2

[0062] The difference from Example 1 is only that δ PCM is 0.9×10 -3 .

[0063] Example 3

[0064] The difference from Example 1 is only that δ PCM is 1.0×10 -3 .

[0065] Example 4

[0066] The difference from Example 1 is only that δ PCM is 1.1×10 -3 .

[0067] Example 5

[0068] The difference from Example 1 is only that δ PCM is 1.2×10 -3 .

[0069] Example 6

[0070] The difference from Example 1 is only that δ PCM is 1.3×10 -3 .

[0071] Example 7

[0072] The difference from Example 1 is only that δ c is 0.005, δ PCM is 0.3×10 -3 .

[0073] Example 8

[0074] The difference from Example 1 is only that δ c0.060, δ PCM 5.9 x 10 -3 .

[0075] Example 9

[0076] The difference from Example 1 is only that δ g 0.2 x 10 -3 , δ PCM 1.2 x 10 -3 .

[0077] Example 10

[0078] The difference from Example 1 is only that δ g 1 x 10 -3 , δ PCM 0.8 x 10 -3 .

[0079] Example 11

[0080] The difference from Example 1 is only that p is 500, δ PCM 2.9 x 10 -3 .

[0081] Example 12

[0082] The difference from Example 1 is only that H is 1.2 x 10 6 , δ PCM 1.35 x 10 -3 .

[0083] In order to highlight the beneficial effects of the embodiments of the present application, the following comparative examples are provided.

[0084] Comparative Example 1

[0085] The difference from Example 1 is only that δ PCM 0.4 x 10 -3 .

[0086] Comparative Example 2

[0087] The difference from Example 1 is only that δ PCM 0.5 x 10 -3 .

[0088] Comparative Example 3

[0089] The difference from Example 1 is only that δ PCM 0.7 x 10 -3 .

[0090] Comparative Example 4

[0091] The difference from Example 1 is only that δ PCM1.55 x 10 -3 .

[0092] Comparative Example 5

[0093] The difference from Example 1 is that δ PCM 1.6 x 10 -3 .

[0094] Comparative Example 6

[0095] The difference from Example 1 is that the battery assembly does not contain a heat sink.

[0096] Comparative Example 7

[0097] The difference from Example 1 is that δ c 0.005, and δ PCM 0.1 x 10 -3 .

[0098] Comparative Example 8

[0099] The difference from Example 1 is that δ c 0.060, and δ PCM 2.9 x 10 -3 .

[0100] Comparative Example 9

[0101] The difference from Example 1 is that δ g 0.2 x 10 -3 , and δ PCM 0.6 x 10 -3 .

[0102] Comparative Example 10

[0103] The difference from Example 1 is that δ g 1 x 10 -3 m, and δ PCM 0.4 x 10 -3 .

[0104] Comparative Example 11

[0105] The difference from Example 1 is that p is 500, and δ PCM 1.4 x 10 -3 .

[0106] Comparative Example 12

[0107] The difference from Example 1 is that H is 1.2 x 10 6 , and δ PCM 0.7 x 10 -3 .

[0108] Comparative Example 13

[0109] The difference from Example 1 is only that δ c is 0.005, δ PCM is 0.7 x 10 -3 .

[0110] Comparative Example 14

[0111] The difference from Example 1 is only that δ c is 0.060, δ PCM is 8.9 x 10 -3 .

[0112] Comparative Example 15

[0113] The difference from Example 1 is only that δ g is 0.2 x 10 -3 , δ PCM is 1.8 x 10 -3 .

[0114] Comparative Example 16

[0115] The difference from Example 1 is only that δ g is 1 x 10 -3 , δ PCM is 1.55 x 10 -3 .

[0116] Comparative Example 17

[0117] The difference from Example 1 is only that p is 500, δ PCM is 4.4 x 10 -3 .

[0118] Comparative Example 18

[0119] The difference from Example 1 is only that H is 1.2 x 10 6 , δ PCM is 2.1 x 10 -3 .

[0120] For ease of reading, the parameters of Example 1 to Example 12, Comparative Example 1 to Comparative Example 18 are summarized in Table 1, and the value of δ PCM / (((-1.823 x 10 5 ) + (2.467 x 10 8 ) δ c + (-5.576 x 10 8 ) δ g + (-3.491 x 10 10 ) δ c δ g ) / pH) is denoted as X.

[0121] Table 1

[0122] Multiple nail penetration tests were conducted on the battery modules of each embodiment and comparative example, and the test results are summarized in Table 2. Specifically, the nail penetration test included: charging the battery module to 100% SOC for each cell, and controlling the initial temperature of each individual cell to 45℃±2℃. A 5mm diameter steel needle was inserted into one individual cell of the battery module at a speed of 1mm / s until thermal runaway occurred, at which point the insertion was stopped (thermal runaway of a cell means that the cell's explosion-proof valve opens and the cell's voltage drops to less than 20% of its initial voltage). After 2 minutes, the needle was removed, with a maximum penetration depth of 80mm. The temperature of adjacent cells within the battery module was continuously observed until it was found to be less than 100℃. If the temperature of adjacent cells was less than 100℃, thermal runaway would not occur. During this process, thermal diffusion between adjacent cells was recorded (thermal diffusion was recorded when the adjacent cell's explosion-proof valve opened and the cell's voltage dropped to less than 20% of its initial voltage).

[0123] Table 2

[0124] Furthermore, the overall energy density of each embodiment and comparative example was calculated. Considering that heat-absorbing elements are provided between any adjacent individual cells in the battery assemblies of the embodiments and comparative examples, the mass of the heat-absorbing elements is added to the individual cells, and the overall mass energy density of the individual cells is calculated. The results of Embodiments 1-12 and Comparative Examples 4-6, and Comparative Examples 13-18 are summarized in Table 3. Specifically, the formula for calculating the overall energy density is as follows: Em=E / (m cell +m pcm )

[0125] In the above formula, E m The overall mass energy density is given by E, where E is the cell energy and m is the total mass energy density. cell For cell quality, m PCM The quality of the heat-absorbing main material.

[0126] The overall mass energy density of the battery cell is shown in the table below when using different thicknesses of the phase change material heat absorption unit.

[0127] Table 3

[0128] It can be seen from the data in Tables 2-3 that the battery assembly provided by the embodiments of the present application not only does not have thermal runaway, but also has a slightly smaller comprehensive energy volume density than the battery assembly without the heat absorption member (Comparative Example 6), indicating that the battery assembly provided by the embodiments of the present application can balance the better heat diffusion inhibition effect and the higher energy density. In addition, although the battery assemblies of Comparative Examples 4-5 and Comparative Examples 13-18 do not have thermal runaway, their comprehensive mass energy densities are not good, which is not conducive to the application of the battery assembly.

[0129] The above is an exemplary embodiment of the present application. It should be noted that those skilled in the art can make some improvements and refinements without departing from the principles of the present application, and these improvements and refinements are also considered within the scope of protection of the present application.

Claims

1. A battery assembly, wherein, The battery assembly comprises: a plurality of single batteries arranged along a first direction, each of the single batteries comprising a shell and a cell accommodated in the shell; a heat absorption member arranged between at least some of the single batteries, the heat absorption member having a heat absorption main material adapted to absorb heat generated by the single batteries, and a gap being present between the cell and the shell on a side of the single battery close to the heat absorption member; wherein the size of the heat-absorbing main material in the first direction is δ PCM m; The dimension of the cell in the first direction is δ c m; The dimension of the gap in the first direction is δ g m; The volume density of the heat-absorbing main material is p kg / m 3 ; a heat absorption amount of the heat absorption main material per unit mass from 25°C to a phase change completion of the heat absorption main material is HJ / kg; the battery assembly satisfies: 0.7 < δ PCM / (((-1.823 x 10 5 ) + (2.467 x 10 8 ) δ c + (-5.576 x 10 8 ) δ g + (-3.491 x 10 10 ) δ c δ g / pH) < 1.

3.

2. The battery assembly of claim 1, wherein, 5 x 10 -3 ≤ δ c ≤ 60 x 10 -3 .

3. The battery assembly of claim 1 or 2, wherein, 0.2 x 10 -3 ≤ δ g ≤ 2 x 10 -3 .

4. The battery assembly of any one of claims 1-3, wherein, ρ≥500.

5. The battery assembly of any one of claims 1-4, wherein, H≥5×10 5 。 6. The battery assembly of any one of claims 1-5, wherein, The heat absorption main material comprises a skeleton and a heat absorption material carried on the skeleton, and a thickness of the heat absorption material in the first direction is greater than or equal to a thickness of the skeleton in the first direction.

7. The battery assembly of claim 6, wherein, The skeleton has a hole, and the heat absorption material is filled in the hole.

8. The battery assembly of any one of claims 1-7, wherein, The heat absorption member further comprises an encapsulating member, and the heat absorption main material is accommodated in the encapsulating member.

9. The battery assembly of any one of claims 1-8, wherein, The single battery is a square single battery, and the heat absorption member is arranged close to a large face of the single battery.

10. An electrical device, comprising: The battery assembly comprises any one of claims 1-9.

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