Battery pack and electric device

Abstract

The embodiment of the application discloses a battery pack and an electric device, and belongs to the technical field of batteries. The main body part of the heat insulation part is spaced apart from the first side surface of the single battery, the edge part of the heat insulation part protrudes towards the first side surface relative to the main body part, and is connected with the first side surface. When the single battery circulates and expands, the gap between the main body part and the first side surface can form a reserved expansion space, reducing the extrusion on the single battery. By arranging the avoiding groove on the side of the main body part towards the first side surface, the reserved expansion space is increased. The maximum depth of the avoiding groove satisfies: H max =1 / 2(L0-AL)-L GAP , which can meet the demand of the uneven expansion of the single battery in the circulation process for space, make the expansion pressure received by the single battery uniform, keep the expansion pressure in a proper range, avoid the performance diving caused by the out-of-range expansion pressure, and guarantee the circulation performance of the single battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a battery pack and a power consumption equipment. BACKGROUND

[0002] In the battery pack, a heat insulation structure is generally arranged between adjacent single batteries to block heat diffusion, reduce the possibility of thermal runaway of the battery pack, and improve the safety performance of the battery pack. The current heat insulation structure cannot adapt to the uneven expansion of the single battery in the cycle process, resulting in rapid attenuation of the battery performance. SUMMARY

[0003] The application embodiments provide a battery pack, which aims to overcome the technical problem that the current heat insulation structure cannot adapt to the uneven expansion of the single battery in the cycle process, resulting in rapid attenuation of the battery performance. Another object of the application embodiments is to provide a power consumption equipment.

[0004] TECHNICAL SOLUTION The application embodiments provide a battery pack, which comprises:

[0005] A single battery has a first direction, and the single battery comprises a first side surface intersecting the first direction;

[0006] A heat insulation member is arranged on one side of the single battery in the first direction, and the heat insulation member comprises a main body part and an edge part. The main body part is spaced apart from the first side surface and is provided with a relief groove facing the first side surface. The edge part is arranged around the circumferential edge of the main body part and protrudes towards the first side surface relative to the main body part, and the edge part is connected to the first side surface.

[0007] The single battery is configured to deform towards the relief groove when swelling occurs;

[0008] In the first direction, the maximum depth of the relief groove is H max mm, the minimum distance between the main body part and the first side surface of the single battery in the initial state of life is L GAP mm, the swelling amount of the single battery when cycled to the end-of-life state in the battery pack is L0 mm, and the deviation amount of the swelling amount of the single battery when cycled to the end-of-life state in the battery pack and the swelling amount of the single battery when cycled to the end-of-life state in the free swelling condition is AL mm; it is satisfied that H max =1 / 2(L0-AL)-L GAP .

[0009] In some embodiments, the monomer battery has a preset pressure P (in MPa) at which the monomer battery circulates in the battery pack, and an equivalent Young's modulus E (in MPa) of the monomer battery, and in the first direction, a second size L of the monomer battery when cycled to an end-of-life state under free expansion conditions is E mm; and satisfies:

[0010] ΔL = P * L E / E.

[0011] In some embodiments, the battery pack further satisfies:

[0012] 0.1≤P≤1.5, and / or, 50≤E≤90.

[0013] In some embodiments, in the first direction, a first size L of the monomer battery when in a start-of-life state is B mm, and a second size L of the monomer battery when cycled to an end-of-life state under free expansion conditions is E mm; and satisfies: L0= L E -L B ;

[0014] wherein, 20.3≤L E ≤128, 20≤L B ≤120.

[0015] In some embodiments, the battery pack further satisfies:

[0016] 0.3≤L0≤8.

[0017] In some embodiments, the battery pack further satisfies:

[0018] 0<H max ≤3.

[0019] In some embodiments, the battery pack further satisfies:

[0020] 0<L GAP ≤4.

[0021] In some embodiments, the battery pack includes a plurality of the monomer batteries arranged along the first direction, and the thermal insulation member is arranged between two adjacent monomer batteries.

[0022] The main body part is provided with the avoidance slot on both sides in the first direction, and the edge part protrudes towards the adjacent monomer battery with respect to the main body part and is connected with the first side of the adjacent monomer battery.

[0023] In some embodiments, in the first direction, the avoidance slot is arranged corresponding to the geometric center of the first side.

[0024] In some embodiments, the first direction is a thickness direction of the single battery, and the first side is a largest-area side of the single battery.

[0025] In some embodiments, the main body part comprises a second side facing the first side, and a profile pattern of the avoiding groove formed on the second side is one of a polygon, a circle, and an ellipse.

[0026] Correspondingly, the power consumption device provided by the embodiments of the present application comprises the battery pack described in any of the above embodiments.

[0027] Beneficial effects: In the battery pack of the embodiments of the present application, the heat insulation member is arranged on one side of the single battery. When the single battery is in thermal runaway, the heat insulation member can block the heat diffusion and reduce the heat diffusion to the nearby single battery, thereby reducing the possibility of overall thermal runaway of the battery pack. By arranging the main body part of the heat insulation member to be spaced apart from the first side of the single battery, the edge part of the heat insulation member protrudes towards the first side relative to the main body part and is connected with the first side, so that when the single battery is cyclically expanded, the gap between the main body part and the first side can form a reserved expansion space, reducing the extrusion on the single battery and improving the safety of the single battery in the cyclic process. By arranging the avoiding groove on the side of the main body part facing the first side, the reserved expansion space is increased, and by arranging the maximum depth H max satisfies: H max = 1 / 2 (L0- AL) - L GAP , the uneven expansion of the single battery in the cyclic process can meet the demand for space, the expansion pressure on the single battery becomes uniform, the expansion pressure can be kept within a suitable range, the performance jump caused by the out-of-range expansion pressure is avoided, and the cyclic performance of the single battery is ensured.

[0028] Compared with the prior art, the power consumption device of the embodiments of the present application can comprise all the technical features and beneficial effects of the above battery pack, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 FIG. 1 is a connection structure diagram of a single battery and a heat insulation member in a battery pack of some embodiments of the present application;

[0031] Figure 2Structure diagram of a single battery in a life starting state for some embodiments of the present application;

[0032] Figure 3 Structure diagram of a single battery in a life ending state for some embodiments of the present application;

[0033] Figure 4 Structure diagram of a single battery and a thermal insulation piece in a battery pack for some embodiments of the present application;

[0034] Figure 5 Structure diagram of a thermal insulation piece for some embodiments of the present application;

[0035] Figure 6 Structure diagram of a thermal insulation piece for some embodiments of the present application along the A-A line; Figure 5 Structure diagram of a thermal insulation piece for some embodiments of the present application along the A-A line;

[0036] Figure 7 Structure diagram of a thermal insulation piece for some embodiments of the present application along the A-A line; Figure 5 Structure diagram of a thermal insulation piece for some embodiments of the present application along the A-A line;

[0037] Figure 8 Structure diagram of a thermal insulation piece for some embodiments of the present application;

[0038] Figure 9 Structure diagram of a thermal insulation piece for some embodiments of the present application along the B-B line; Figure 8 Structure diagram of a thermal insulation piece for some embodiments of the present application along the B-B line;

[0039] Figure 10 Structure diagram of a thermal insulation piece for some embodiments of the present application along the B-B line; Figure 8 Structure diagram of a thermal insulation piece for some embodiments of the present application along the B-B line;

[0040] Figure 11 Structure diagram of a thermal insulation piece for some embodiments of the present application;

[0041] Figure 12 Structure diagram of a thermal insulation piece for some embodiments of the present application along the C-C line; Figure 11 Structure diagram of a thermal insulation piece for some embodiments of the present application along the C-C line;

[0042] Figure 13 Structure diagram of a thermal insulation piece for some embodiments of the present application along the C-C line; Figure 11 Structure diagram of a thermal insulation piece for some embodiments of the present application along the C-C line;

[0043] Figure 14 Structure diagram of a battery pack for some embodiments of the present application;

[0044] Figure 15 Structure diagram of a preset pressure measurement for a single battery cycle;

[0045] Reference numerals: 100 - single battery; 110 - first side surface; 200 - thermal insulation member; 210 - main body portion; 211 - avoiding groove; 212 - second side surface; 220 - edge portion; 300 - thin film pressure sensor. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative work fall within the scope of protection of the present application.

[0047] In the description of the present application, it should be understood that the terms "thickness", "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, the meaning of "a plurality of" is two or more, and at least one refers to one, two or more, unless otherwise explicitly specified. The terms "mounting", "connecting", "connecting" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features.

[0048] In the description of the present application, the first direction X is introduced to more clearly describe the shape and / or structure of each component in the battery pack, and the connection relationship and / or relative positional relationship between components. The first direction X is the arrangement direction of the single battery 100 and the thermal insulation member 200. In the drawings, the first direction X is indicated by an arrow marked X. It can be understood that the first direction X can also be the opposite direction of the direction indicated by the arrow. Alternatively, when the single battery 100 is a square battery, the first direction X can correspond to the thickness direction of the single battery 100, i.e., it can be the arrangement direction of the two large faces (the side with the largest area) of the single battery 100.

[0049] As a prologue of the present application, some battery packs may cause uneven expansion of the internal single batteries during the cycle process, and thus the single batteries are subjected to uneven pressure, which may cause rapid performance degradation of the single batteries. In view of this, the embodiments of the present application provide a battery pack which can effectively reduce the influence caused by uneven expansion of the single batteries, so as to make the stress of the single battery expansion uniform and protect the cycle performance.

[0050] Please refer to Figure 1 and Figure 14 The battery pack of the embodiments of the present application includes a single battery 100 and a thermal insulation piece 200.

[0051] The single battery 100 is an energy storage unit for storing and providing electric energy in the battery pack, and its structure can include a shell, an electrode assembly, positive and negative electrodes, an electrolyte, etc. The electrode assembly and the electrolyte are arranged inside the shell, and the positive and negative electrodes are arranged on the shell and electrically connected with the electrode assembly to lead out the circuit. The single battery 100 can be a lithium ion battery, a nickel-cadmium battery, a lead-acid battery, etc.

[0052] The single battery 100 includes a first side surface 110 intersecting the first direction X, which can be an outer side surface of the shell of the single battery 100 arranged towards the thermal insulation piece 200. The first side surface 110 intersects the first direction X, that is, the first side surface 110 is not parallel to the straight line extending in the first direction X, and has an included angle therebetween. Among all the straight lines extending in the first direction X, at least one straight line can intersect the first side surface 110 at a point.

[0053] Optionally, the first side surface 110 can be planar or curved. It should be noted that the first side surface 110 can not be a standard plane or curve, but only needs to be approximately planar or arc-shaped. For the planar first side surface 110, it can have slight curved features or slight geometric deformation thereon.

[0054] Optionally, the first side surface 110 is perpendicular to the first direction X, that is, the first side surface 110 can be a planar structure perpendicular to the first direction X.

[0055] The thermal insulation piece 200 is arranged on one side of the single battery 100 in the first direction X, and when the single battery 100 is in thermal runaway, the thermal insulation piece 200 can block the heat diffusion, reduce the risk of thermal runaway diffusion of the battery pack, and improve the safety of the battery pack. The thermal insulation piece 200 can be made of aerogel method, and its material can be one or a mixture of two or more of pre-oxidized silk, silica aerogel, alumina aerogel and zirconia aerogel.

[0056] The heat insulation piece 200 includes a main body part 210 and an edge part 220. The main body part 210 of the heat insulation piece 200 is spaced apart from the first side surface 110, that is, a gap is formed between the main body part 210 and the first side surface 110. When the single battery 100 is cyclically expanded, the gap between the main body part 210 and the first side surface 110 can provide an expansion space for the single battery 100, that is, the gap between the main body part 210 and the first side surface 110 can serve as an expansion gap reserved for the expansion of the single battery 100, thereby reducing the extrusion of the single battery 100 and improving the cycle performance of the single battery 100. In addition, the main body part 210 is provided with a relief groove 211 facing the first side surface 110. The relief groove 211 can effectively increase the expansion space and further improve the cycle performance of the single battery 100.

[0057] The edge part 220 of the heat insulation piece 200 is arranged around the circumferential edge of the main body part 210 and protrudes towards the first side surface 110 relative to the main body part 210, and the edge part 220 is connected to the first side surface 110. That is, the frame-shaped structure formed by the edge part 220 can surround the main body part 210 on the inner side thereof, or the frame-shaped structure formed by the edge part 220 extends along the circumferential edge contour line of the main body part 210, and the main body part 210 is arranged on the side of the edge part 220 away from the first side surface 110. The main body part 210 and the edge part 220 are connected to each other and can be an integrated structure integrally formed, or can be a split structure formed by splicing each other.

[0058] The heat insulation piece 200 is connected to the first side surface 110 of the single battery 100 through the edge part 220 thereof, and the main body part 210 is spaced apart from the first side surface 110 of the single battery 100 through the edge part 220 thereof, so as to maintain the expansion gap between the main body part 210 and the first side surface 110.

[0059] The single battery 100 is configured to deform towards the inside of the relief groove 211 when expanding. It should be noted that when the single battery 100 expands, the first side surface 110 thereof deforms to protrude towards one side, and the protruding direction points to the relief groove 211. When the expansion is relatively slight, the protruding deformation is small and can be outside the relief groove 211. As the expansion gradually intensifies, the protruding deformation becomes large to a certain extent and can enter the relief groove 211.

[0060] In the embodiment of the present application, as shown in FIG. 1, Figure 1 the maximum depth of the relief groove 211 in the first direction X is H maxmm. It should be noted that the depth of each position in the avoidance groove 211 is as follows: taking the side of the main body part 210 closest to the first side surface 110 as the reference surface, the distance between the corresponding inner wall of the avoidance groove 211 and the reference surface in the first direction X is the depth of the position, and the depths of each position in the avoidance groove 211 can be the same or different. The maximum depth H max of the avoidance groove 211 is the maximum value of the depths of all positions. The maximum depth can be measured by a vernier caliper, a micrometer, a laser range finder, or other optical distance measuring devices.

[0061] Optionally, 0 < H max ≤ 3, that is, the maximum depth of the avoidance groove 211 in the first direction X can be controlled within 3 mm, for example, H max may be any value or a range value between any two values of 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0. In this way, it can not only ensure that the single battery 100 has enough expansion space for cycle expansion, but also keep the pressure of the heat insulation part 200 on the first side surface 110 within a suitable range, thereby promoting the cycle performance of the single battery 100. In addition, it can also reduce the occupation of the internal space of the battery pack, thereby ensuring the volume energy density of the battery pack.

[0062] As shown in FIG. 1, Figure 1 the minimum distance L GAP mm between the main body part 210 and the first side surface 110 of the single battery 100 in the beginning of life state. It should be noted that the beginning of life state is a state in which the single battery 100 is stored at room temperature for ≤30 days after being taken offline, and has not undergone cycle or small current (≤1 / 3C) cycle for less than 3 times. The minimum distance L GAP is the minimum distance between the above-mentioned reference surface and the first side surface 110 in the first direction X when the single battery 100 is in the beginning of life state. The minimum distance L GAP may also be measured by a vernier caliper, a micrometer, a laser range finder, or other optical distance measuring devices when the single battery 100 is in the beginning of life state.

[0063] Optionally, 0 < L GAP ≤ 4, that is, the minimum distance L GAP between the main body part 210 and the first side surface 110 of the single battery 100 in the beginning of life state can be controlled within 4 mm, for example, L may be any value or a range value between any two values of 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0. In this way, it can not only reserve a gap for the cycle expansion of the single battery 100, but also reduce the occupation of the internal space of the battery pack, thereby ensuring the volume energy density of the battery pack.

[0064] Please refer to Figure 2 and Figure 3 As shown in FIG. 1, the expansion amount of the single battery 100 when cycled to the end of life state under the free expansion condition is L0 mm. It should be noted that the free expansion condition is the cycle state of the single battery 100 without the constraint or limitation of the heat insulation member 200 and other components, and when the single battery 100 is cycled under the free expansion condition, the first side surface 110 of the single battery 100 is not subjected to external force or subjected to external force which has little effect on the cycle and can be ignored; the end of life state is a state in which the capacity of the single battery 100 decays to 70% of the capacity at the start of life.

[0065] Optionally, 0.3≤L0≤8, that is, the expansion amount of the single battery 100 when cycled to the end of life state under the free expansion condition can be controlled within 0.3 mm to 8 mm, for example, L0 can be any value in 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0 or a range value between any two values, controlling the expansion amount of the single battery 100 when cycled to the end of life state under the free expansion condition within the above range can enable the single battery 100 to meet most application scenarios of the battery pack.

[0066] The expansion amount L0 can be measured by respectively measuring the first dimension L B mm of the single battery 100 at the start of life in the first direction X, and the second dimension L E mm of the single battery 100 when cycled to the end of life state under the free expansion condition in the first direction X, and L E -L B L0 is calculated.

[0067] Wherein, the first dimension L B may be the average thickness of the single battery 100 in the first direction X at the start of life, and the second dimension L E may be the maximum thickness of the single battery 100 in the first direction X when cycled to the end of life state under the free expansion condition. The two dimensions can be directly measured by using a dimension measuring tool under the corresponding state and condition, for example, the first dimension L B is directly measured by a vernier caliper at the start of life of the single battery 100, and the second dimension L EAlternatively, the first side surface 110 can be divided into a plurality of lattice regions in an array. In a life starting state of the single battery 100, the thickness of the central lattice region is measured by the height gauge as the first size L B In a life ending state of the single battery 100, the thickness of each lattice region is measured by the height gauge, and the maximum thickness is taken as the second size L E Alternatively, L0may also be calculated by simulation.

[0068] In some embodiments, 20.3≤L E ≤128, 20≤L B ≤120. That is, the first size can be controlled to be 20.3 mm to 128 mm, for example, L B may be any value in 20.3, 22.8, 25.3, 27.8, 30.3, 32.8, 35.3, 37.8, 40.3, 42.8, 45.3, 47.8, 50.3, 52.8, 55.3, 57.8, 60.3, 62.8, 65.3, 67.8, 70.3, 72.8, 75.3, 77.8, 80.3, 82.8, 85.3, 87.8, 90.3, 92.8, 95.3, 97.8, 100.3, 102.8, 105.3, 107.8, 110.3, 112.8, 115.3, 117.8, 120.3, 122.8, 125.3, 127.8, 128, or a range value between any two values. The second size can be controlled to be 20 mm to 120 mm, for example, L E may be any value in 20, 22.5, 25, 27.5, 30, 32.5, 35, 37.5, 40, 42.5, 45, 47.5, 50, 52.5, 55, 57.5, 60, 62.5, 65, 67.5, 70, 72.5, 75, 77.5, 80, 82.5, 85, 87.5, 90, 92.5, 95, 97.5, 100, 102.5, 105, 107.5, 110, 112.5, 115, 117.5, 120, or a range value between any two values. Controlling the first size and the second size in the above range respectively can meet the application scenarios of most battery packs, and also enable the single battery 100 to have better cycle performance.

[0069] The difference between the expansion amount of the single battery 100 when cycled to the end-of-life state in the battery pack and the expansion amount of the single battery 100 when cycled to the end-of-life state under free expansion conditions is ΔL mm, and the difference ΔL in the expansion amount can be obtained by measuring the expansion amount of the single battery 100 when cycled to the end-of-life state in the battery pack and the expansion amount of the single battery 100 when cycled to the end-of-life state under free expansion conditions, respectively, and then calculating. It can also be calculated in a simulated manner.

[0070] The battery pack satisfies: H max = 1 / 2 (L0- ΔL) - L GAP The avoidance groove 211 can meet the demand of space for the uneven expansion of the single battery 100 during the cycling process, and the expansion pressure received by the single battery 100 becomes uniform, and the expansion pressure can be kept within a suitable range, avoiding the expansion pressure out of range and causing performance to drop, and ensuring the cycling performance of the single battery 100.

[0071] In some embodiments, the single battery 100 can be a square battery, and the first direction X corresponds to the thickness direction of the single battery 100, and the first side surface 110 is the largest surface (large surface) of the single battery 100. For a square battery, the expansion phenomenon of the large surface is more serious than that of other side surfaces, and by arranging the heat insulation member 200 on the side of the large surface, and using the main body part 210 to separate the large surface and the main body part 210, and the avoidance groove 211 of the main body part 210, space is reserved for the expansion of the large surface, which can more effectively improve the cycling performance of the single battery 100.

[0072] In some embodiments, in the first direction X, the avoidance groove 211 is arranged corresponding to the geometric center of the first side surface 110. It should be noted that in the present application, the geometric center is the intersection position of each diagonal line of the first side surface 110, and the geometric center can not only refer to the center point of the first side surface 110, but also include a central region extending from the center point to the edge. The expansion of the geometric center of the first side surface 110 is more serious than that of the edge position during the cycling of the single battery 100, and the position of the avoidance groove 211 is arranged corresponding to the geometric center of the first side surface 110, so that it can more match the expansion deformation region of the first side surface 110, more accurately reserve space for expansion, and make the expansion of the single battery 100 more uniform, and further improve the cycling performance.

[0073] In some embodiments, the preset pressure of the single battery 100 when cycled in the battery pack is P MPa, the equivalent Young's modulus of the single battery 100 is E MPa, and in the first direction X, the second size of the single battery 100 when cycled to the end-of-life state under free expansion conditions is L E mm; satisfies: ΔL = P * L E / E. The equivalent Young's modulus E of the single cell 100 can be measured using the following method: The single cell 100 is placed stably, and then a compression test is performed on the single cell 100 using a compression head with the same dimensions as the first side 110 of the single cell 100. The force-displacement curve of the single cell 100 is recorded, and the result is determined based on the force-displacement curve of the single cell 100 and the first dimension L of the single cell 100 at the beginning of its lifespan. B The equivalent Young's modulus E of a single cell was calculated. Therefore, the maximum depth H of the clearance groove 211 in the battery pack is... max Satisfying H max =1 / 2(L0-P*L) E / E)-L GAP This allows the individual cell 100 to cyclically expand under a more suitable preset pressure, thereby achieving better cycle performance.

[0074] Please refer to the appendix for details. Figure 15 The preset pressure of a single cell 100 circulating within the battery pack can be measured using the following method:

[0075] (1) Record the thickness M of the heat insulation component 200 connected to the target single cell 100 inside the battery pack, and then remove the target single cell 100, the heat insulation components 200 on both sides and the single cells 100 on both sides.

[0076] (2) Assemble the target single cell 100, the heat insulation components 200 on both sides, the single cells 100 on both sides, and the thin-film pressure sensor 300. Figure 15 Stack them as shown;

[0077] (3) Place a steel plate on top of the stacked individual cells 100 and perform a compression test. Stop the compression when the thickness of the heat insulation component 200 becomes the thickness recorded in the battery pack, and record the pressure on the thin film pressure sensor 300 to obtain the preset pressure. Optionally, a universal testing machine can be used.

[0078] Optionally, the battery pack also satisfies: 0.1 ≤ P ≤ 1.5. That is, the preset pressure for cycling can be set between 0.1 MPa and 1.5 MPa. For example, P can be any value or a range between any two values ​​from 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, and 1.5. Setting the preset pressure for cycling the individual battery 100 within the battery pack within the above range can give the individual battery 100 better cycle performance.

[0079] Optionally, the battery pack also satisfies: 50≤E≤90. That is, the equivalent Young's modulus of the single battery 100 can be controlled in the range of 50Mpa to 90Mpa, for example, E can be any value in 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 or a range value between any two values, controlling the value of the equivalent Young's modulus of the single battery 100 in the above range, on the one hand, it satisfies most of the application scenarios of the battery pack, and on the other hand, it can make the single battery 100 have better cycle performance.

[0080] Please refer to Figure 4 In some embodiments, the battery pack includes a plurality of single batteries 100 arranged along the first direction X, and the heat insulation piece 200 is arranged between two adjacent single batteries 100; the main body part 210 is provided with a relief groove 211 on both sides in the first direction X, and the edge part 220 protrudes towards the adjacent two single batteries 100 with respect to the main body part 210 and is connected with the first side surface 110 of the adjacent two single batteries 100 respectively. Thus, the cycle expansion requirement of the single batteries 100 on both sides of the heat insulation piece 200 can be met, and the arrangement requirement of the whole pack is met, so that the performance of the battery pack is improved as a whole.

[0081] Please refer to Figures 5 to 13 In some embodiments, the main body part 210 includes a second side surface 212 facing the first side surface 110, and the profile pattern of the relief groove 211 formed on the second side surface 212 is one of a polygon, a circle, an ellipse, and an irregular pattern, so as to match the shape of the expansion of the first side surface 110, so that the pressure received by the cycle expansion of the single battery 100 is more uniform, and the cycle performance is further improved.

[0082] The following provides examples and comparative examples to demonstrate the performance of the battery pack of the present application, wherein the heat insulation piece 200 can be pasted on the first side surface 110 of the single battery 100, and then two steel clamps are used to constrain the single battery 100, and the pre-tightening force is 100kgf, so as to simulate the state of the single battery 100 inside the battery pack. Then, according to the condition of 1C charging / 1C discharging, the cycle is carried out, and when the single battery 100 is cycled to the capacity retention rate of 80%, the cycle number of the battery cell is recorded. The specific example and comparative example data are shown in Table 1 below:

[0083]

[0084] As shown in the above table, the H max=1 / 2(L0-P*L E / E)-L GAP , while H max >1 / 2(L0-P*L E / E)-L GAP , while H max <1 / 2(L0-P*L E / E)-L GAP The cycle number of the monomer battery 100 of the embodiment is significantly improved compared with the cycle number of Comparative Example 1 and Comparative Example 2. In Embodiment 14 and Embodiment 15, the preset pressure is outside the range of 0.1 Mpa to 1.5 Mpa, and the preset pressure of other embodiments is within the range. Compared with Embodiments 14 and 15, the cycle number of the monomer battery 100 of other embodiments is better, and therefore the preset pressure within the range of 0.1 Mpa to 1.5 Mpa can obtain better cycle effect.

[0085] As Figure 14 The external structure of the battery pack of some embodiments of the present application is shown, which is used to store and provide electric energy, and can be applied to electric vehicles, hybrid vehicles, portable electronic devices, unmanned aerial vehicles and other electric devices. Accordingly, the electric device provided by the embodiments of the present application can be various types of devices such as new energy vehicles, computers, energy storage power supply devices, etc. It can be understood that the electric device can include all technical features and beneficial effects of the above-mentioned battery pack, which will not be described here.

[0086] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0087] The battery pack and electric device provided by the embodiments of the present application are described in detail above, and the principles and implementation modes of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the technical solutions and core ideas of the present application; those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery pack, characterized by, The battery pack comprises: a single battery having a first direction, the single battery comprising a first side surface intersecting the first direction; a thermal insulation member arranged on one side of the single battery in the first direction, the thermal insulation member comprising a main body portion and an edge portion; the main body portion is spaced apart from the first side surface and is provided with a relief groove facing the first side surface; the edge portion is arranged around the circumferential edge of the main body portion and protrudes towards the first side surface relative to the main body portion, and the edge portion is connected to the first side surface; the single battery is configured to deform towards the relief groove when swelling occurs; In the first direction, the maximum depth of the avoidance groove is H max mm, 0 < H max ≤ 3, the minimum distance between the main body part and the first side surface of the unit cell in a life start state is L GAP mm, 0 < L GAP ≤ 4, the expansion amount of the unit cell when cycled to a life end state in a free expansion condition is L0 mm, 0.3 ≤ L0 ≤ 8, and the deviation amount of the expansion amount of the unit cell when cycled to the life end state in the battery pack and the expansion amount when cycled to the life end state in the free expansion condition is ΔL mm; H max = 1 / 2(L0-ΔL)-L GAP is satisfied.

2. The battery pack of claim 1, wherein, The preset pressure of the circulation of the single battery in the battery pack is P MPa, the equivalent Young's modulus of the single battery is E MPa, and the second size of the single battery in the first direction when the single battery is circulated to the end-of-life state under the free expansion condition is L E mm; and the following conditions are met: ΔL = P x L E / E.

3. The battery pack of claim 2, wherein, the battery pack further satisfies: 0.1 ≤ P ≤ 1.5, and / or, 50 ≤ E ≤ 90.

4. The battery pack of any one of claims 1-3, wherein, In the first direction, a first dimension of the unit cells at a beginning of life state is L0 B mm, a second dimension at an end of life state under free swelling conditions is L E mm; with L0 = L E - L B ; wherein 20.3≤L E ≤128, 20≤L B ≤120.

5. The battery pack of claim 1, wherein, The battery pack comprises a plurality of single batteries arranged in the first direction, and the thermal insulation member is arranged between two adjacent single batteries; the main body portion is provided with the relief groove on both sides in the first direction, and the edge portion protrudes towards the first side surface of the adjacent single battery relative to the main body portion and is connected to the first side surface of the adjacent single battery.

6. The battery pack of claim 1, wherein, In the first direction, the relief groove is arranged corresponding to the geometric center of the first side surface.

7. The battery pack of claim 1, wherein, The first direction is the thickness direction of the single battery, and the first side surface is the largest area surface of the single battery.

8. The battery pack of claim 1, wherein, The main body portion comprises a second side surface facing the first side surface, and the profile pattern of the relief groove formed on the second side surface is one of a polygon, a circle, and an ellipse.

9. An electric device, characterized by The battery pack as claimed in any one of claims 1 to 8.

Images