Battery pack and electric device

Abstract

The utility model discloses a battery pack and a power utilization device, the battery pack has a first direction and comprises a first end plate, a second end plate and a plurality of battery monomers, the plurality of battery monomers are arranged along the first direction to form a battery pack, the first end plate is arranged on one side of the battery pack along the first direction, and the second end plate is arranged on the other side of the battery pack; a first expansion space is formed between the first end plate and the battery monomer close to the first end plate, the second end plate is arranged on the other side of the battery pack along the first direction, and a second expansion space is formed between the second end plate and the battery monomer close to the second end plate; wherein in the first direction, the size of the first expansion space is L1, the size of the second expansion space is L2, and L2 > L1 > 0. The expansion spaces between the two end plates and the adjacent battery monomers are different, so that the absorbable expansion deformations are different, and the corresponding expansion spaces can be provided when the expansion forces of the battery monomers on the two end plate sides are different, so that the relative balance of the expansion forces of the battery monomers on the two end plate sides is realized, and the service life of the battery is better prolonged.

Description

Technical Field

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

[0002] A battery pack usually includes a plurality of battery cells arranged in a certain direction. Since the battery cells expand during charge and discharge, there needs to be an expansion space between adjacent battery cells accordingly. However, limited by the fixing method and placement position of the plurality of battery cells in the battery pack, the expansion forces of the battery cells at both ends differ greatly along the arrangement direction of the battery cells, which will reduce the service life of the battery pack. Summary of the Utility Model

[0003] Utility Model Objective: The embodiments of this application provide a battery pack, aiming to solve the problem that the large difference in the expansion forces of the battery cells in the existing battery pack reduces the service life of the battery pack; another objective of the embodiments of this application is to provide an electrical device.

[0004] Technical Solution: A battery pack described in the embodiments of this application has a first direction and includes:

[0005] A plurality of battery cells arranged in the first direction to form a battery group;

[0006] A first end plate disposed on one side of the battery group along the first direction, and there is a first expansion space between the first end plate and the battery cell adjacent to it;

[0007] A second end plate disposed on the other side of the battery group along the first direction, and there is a second expansion space between the second end plate and the battery cell adjacent to it;

[0008] Wherein, along the first direction, the size of the first expansion space is L1 mm, and the size of the second expansion space is L2 mm, satisfying:

[0009] L2 > L1 > 0.

[0010] In some embodiments, along the first direction, there is a third expansion space between two adjacent battery cells, and the size of the third expansion space is L0 mm, satisfying:

[0011] L0 ≥ L2 > L1 > 0.

[0012] In some embodiments, along the first direction, it satisfies:

[0013] 0 < L1 ≤ L0 / 2;

[0014] L1 < L2 ≤ 2L1.

[0015] In some embodiments, L0 satisfies: 0.35 < L0 < 0.9.

[0016] In some embodiments, the first end plate is provided with a first groove, an opening of the first groove faces the battery cell connected to the first end plate, and the first groove forms the first expansion space; along the first direction, a front projection of the battery cell on the first end plate covers the first groove; on a side of the first end plate facing the battery cell, a minimum distance L3 mm exists between a notch edge of the first groove and an outer edge of the first end plate, and satisfies: 5 ≤ L3 ≤ 15.

[0017] In some embodiments, the second end plate is provided with a second groove, an opening of the second groove faces the battery cell connected to the second end plate, and the second groove forms the second expansion space; along the first direction, a front projection of the battery cell on the second end plate covers the second groove;

[0018] On a side of the second end plate facing the battery cell, a minimum distance L4 mm exists between a notch edge of the second groove and an outer edge of the second end plate, and satisfies: 5 ≤ L4 ≤ 15.

[0019] In some embodiments, a separator is further included, the separator is disposed between two adjacent battery cells and is connected to the two adjacent battery cells; the separator is provided with a through hole, the through hole is disposed opposite to side surfaces of the two adjacent battery cells along the first direction, and the through hole forms the third expansion space; a minimum distance L5 mm exists between a hole wall of the through hole and an outer edge of the separator, and satisfies: 5 ≤ L5 ≤ 15.

[0020] In some embodiments, along the first direction, a connection area between the first end plate and the battery cell adjacent thereto is S1 mm 2 , a connection area between the second end plate and the battery cell adjacent thereto is S2 mm 2 , a connection area between the separator and the battery cell adjacent thereto is S3 mm 2 , and satisfies:

[0021] S1 = S2 = S3.

[0022] In some embodiments, the separator is a flexible energy absorption member.

[0023] In some embodiments, the battery pack has a second direction intersecting with the first direction, the battery pack includes two side plates spaced along the second direction, the two side plates are oppositely disposed on two sides of the battery pack along the second direction and are respectively connected to each battery cell of the battery pack.

[0024] In some embodiments, it includes:

[0025] A plurality of the battery packs, wherein two of the battery packs are arranged at intervals along the first direction;

[0026] A first plate body, extending along the second direction and disposed between two adjacent battery packs along the first direction, and the second end plate is disposed between the first plate body and the battery pack;

[0027] A second plate body, extending along the second direction and disposed on a side of the battery pack away from the first plate body; along the first direction, the first end plate is disposed between the second plate body and the battery pack;

[0028] Wherein, along the first direction, the size of the first plate body is L6 mm, and the size of the second plate body is L7mm, satisfying: L6 > L7.

[0029] Correspondingly, an electrical device according to an embodiment of the present application includes a battery pack as described in any one of the foregoing embodiments.

[0030] Beneficial effects: Compared with the prior art, a battery pack according to an embodiment of the present application has a first direction, includes a first end plate, a second end plate and a plurality of battery cells, and the plurality of battery cells are arranged along the first direction to form a battery pack. The first end plate is disposed on one side of the battery pack along the first direction, and there is a first expansion space between the first end plate and the adjacent battery cell. The second end plate is disposed on the other side of the battery pack along the first direction, and there is a second expansion space between the second end plate and the adjacent battery cell; wherein, along the first direction, the size of the first expansion space is L1 mm, and the size of the second expansion space is L2 mm, satisfying: L2 > L1 > 0. By setting different expansion spaces between the two end plates and the adjacent battery cells, the absorbed expansion deformations are also different. Therefore, corresponding expansion spaces can be provided when the expansion forces of the battery cells on both end plate sides are different, so as to achieve relatively balanced expansion forces of the battery cells on both end plate sides, reduce the expansion force difference between the battery cells on both end plate sides, and thus better extend the battery service life.

[0031] Compared with the prior art, an electrical device according to an embodiment of the present application includes a battery pack as described in any one of the foregoing embodiments. It can be understood that the electrical device according to the embodiment of the present application can have all the technical features and corresponding beneficial effects of the above battery pack, which will not be elaborated herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 is a schematic structural diagram of a battery pack according to an embodiment of the present application;

[0034] Figure 2 is an exploded view of a battery pack according to an embodiment of the present application;

[0035] Figure 3 is a cross-sectional view of a battery pack according to an embodiment of the present application;

[0036] Figure 4 is a cross-sectional view of a battery pack according to an embodiment of the present application;

[0037] Figure 5 is a schematic structural diagram of the first end plate according to an embodiment of the present application;

[0038] Figure 6 is a right view of the first end plate according to an embodiment of the present application;

[0039] Figure 7 is a schematic structural diagram of the second end plate according to an embodiment of the present application;

[0040] Figure 8 is a left view of the second end plate according to an embodiment of the present application;

[0041] Figure 9 is a schematic structural diagram of the separator according to an embodiment of the present application;

[0042] Figure 10 is a left view of the separator according to an embodiment of the present application;

[0043] Figure 11 is a schematic structural diagram of another battery pack according to an embodiment of the present application;

[0044] Figure 12 is Figure 11 a cross-sectional view of the battery pack in;

[0045] Figure 13 is Figure 12 an enlarged view of part A in;

[0046] Figure 14 is Figure 12 an enlarged view of part B in.

[0047] Reference numerals: 1, battery pack; 11, battery cell; 2, first end plate; 21, first groove; 3, second end plate; 31, second groove; 4, first expansion space; 5, second expansion space; 6, third expansion space; 7, separator; 71, through hole; 8, side plate; 9, first plate body; 10, second plate body; X, first direction; Y, second direction. Detailed implementation

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0049] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality of" means two or more, and at least one means one, two or more, unless otherwise specifically defined. In the description of the present application, "vertical" means completely vertical at 90° or almost completely vertical. For example, within the range of an included angle of 80° to 100°, it is considered vertical. Similarly, "parallel" means completely parallel or almost completely parallel. For example, within a range of 10° of complete parallelism, it is considered parallel.

[0050] It should also be noted that in the accompanying drawings of the present application, the arrow marked with X indicates the first direction X, and the arrow marked with Y indicates the second direction Y. In the embodiments of the present application, the first direction X is the direction in which a plurality of battery cells 11 are arranged, which can also be said to be the length direction of the battery pack; the second direction Y is the extending direction of the first plate body and the second plate body, which can also be said to be the width direction of the battery pack; the introduction of the first direction X and the second direction Y is to facilitate the description of the structural position relationship of the various components of the battery pack, and thus facilitate the understanding of its structure. In the embodiments of the present application, the first direction X and the second direction Y are preferably perpendicular to each other.

[0051] In order to have better endurance, a power battery pack usually arranges a plurality of battery cells in a first direction to form a battery pack, and end plates are arranged at both ends of the battery pack. During the daily use of the battery pack, the battery cells will start to expand due to continuous charging and discharging. Due to the fixing method of the battery pack and the different placement positions in the battery pack housing, there will be a problem that the expansion forces of the two battery cells connected to the end plates are quite different.

[0052] In view of this, an embodiment of the present application proposes a battery pack aimed at solving the above problems.

[0053] Please refer to Figures 1-4 , a battery pack provided by an embodiment of the present application has a first direction X, and includes a first end plate 2, a second end plate 3, and a plurality of battery cells 11. The plurality of battery cells 11 are arranged in the first direction X to form a battery pack 1. The first end plate 2 is arranged on one side of the battery pack 1 along the first direction X. There is a first expansion space 4 between the first end plate 2 and the adjacent battery cell 11. The second end plate 3 is arranged on the other side of the battery pack 1 along the first direction X. There is a second expansion space 5 between the second end plate 3 and the adjacent battery cell 11. Among them, along the first direction X, the size of the first expansion space 4 is L1 mm, and the size of the second expansion space 5 is L2 mm, satisfying: L2 > L1 > 0.

[0054] In the embodiment of the present application, by setting different expansion spaces between the two end plates and the adjacent battery cells 11, the absorbable expansion deformations are also different. Therefore, when the expansion forces of the battery cells 11 on both end plate sides are different, corresponding expansion spaces can be provided to achieve relatively balanced expansion forces of the battery cells 11 on both end plate sides, reduce the expansion force difference between the battery cells 11 on both end plate sides, and thus better extend the battery service life.

[0055] Specifically, in the embodiments of the present application, multiple battery cells 11 are arranged along the first direction X, and two adjacent batteries along the first direction X are adhesively fixed. After continuous charging and discharging of the battery pack, some of the battery cells 11 begin to expand. Since the multiple battery cells 11 are adhesively formed into a battery pack 1, when one or more battery cells 11 in the battery pack 1 expand and deform, it will be transmitted to the adjacent battery cells 11. Therefore, the expansion and deformation of the battery cells 11 will be transmitted to both sides of the battery cells 11 along the first direction X. Since the battery cells 11 located in the middle of the battery pack 1 may be squeezed by the expansion and deformation of the batteries on both sides, the expansion force generated by the expansion and deformation will be transmitted between the battery cells 11 in the battery pack 1. Correspondingly, the battery cells 11 located in the middle of the battery pack 1 are relatively capable of receiving the expansion force. However, when the expansion force is transmitted to the battery cells 11 at both ends along the first direction X, the end plates absorb the expansion force by providing an expansion space between the end plates and the battery cells 11. Due to the different fixed positions and fixing methods of the battery pack 1 in the battery pack housing, the working conditions corresponding to the first end plate 2 and the second end plate 3 are different, resulting in the first end plate 2 being able to provide deformation in the direction away from the battery cells 11 along the first direction X, while the second end plate 3 cannot provide deformation in the direction away from the battery cells 11 along the first direction X. At this time, there may be a situation where the expansion forces received by the battery cells 11 at both ends of the battery pack 1 along the first direction X are different or even vary greatly. The battery cells 11 with a larger expansion force will have a shorter service life, which correspondingly affects the service life of the battery pack. Therefore, in the present application, a first expansion space 4 is provided between the first end plate 2 and the adjacent battery cells 11, and a second expansion space 5 is provided between the second end plate 3 and the adjacent battery cells 11, which are respectively used to absorb the expansion and deformation of the battery cells 11. Along the first direction X, the size of the first expansion space 4 is smaller than the size of the second expansion space 5. At this time, the second expansion space 5 can absorb more expansion force compared to the first expansion space 4, so as to achieve relatively balanced expansion forces on the battery cells 11 at both ends of the battery pack 1 along the first direction X, and avoid the problem that the expansion and deformation of the battery cells 11 on the second end plate 3 side cannot be absorbed, resulting in a large expansion force in the battery cells 11 and a reduction in the service life of the battery cells 11.

[0056] Therefore, in the embodiments of the present application, by setting different expansion spaces between the first end plate 2 and the second end plate 3 and the battery cells 11 to absorb different amounts of expansion deformation of the battery cells 11, the gap in the expansion forces received by the battery cells 11 connected to the first end plate 2 and the second end plate 3 is reduced, so as to achieve relatively balanced expansion forces on the battery cells 11 in the battery pack 1 when the battery cells 11 expand during charging and discharging of the battery pack, and ensure the service life of the battery pack.

[0057] It should be noted that in specific use, the first end plate 2 is arranged on the side with relatively small external anti-deformation force, and the second end plate 3 is arranged on the side with relatively large external anti-deformation force. Therefore, when the battery cell 11 in the battery pack expands and deforms, the first end plate 2 may deform in the direction away from the battery cell 11 to further absorb the expansion force of the battery cell 11. The second end plate 3 cannot deform in the direction away from the battery cell 11. Therefore, it is correspondingly necessary to set the second expansion space 5 between the second end plate 3 and the battery cell 11 to be larger than the first expansion space 4 between the first end plate 2 and the battery cell 11, so as to directly absorb the expansion force of the battery cell 11 by using the second expansion space 5.

[0058] In some embodiments, along the first direction X, there is a third expansion space 6 between two adjacent battery cells 11. The size of the third expansion space 6 is L0 mm, satisfying: L0≥L2>L1>0.

[0059] In the embodiments of the present application, by setting a third expansion space 6 between two adjacent battery cells 11, the deformation generated by the expansion of the battery cell 11 can be absorbed, the expansion force inside the battery cell 11 can be reduced, and the extrusion force between adjacent battery cells 11 can also be reduced.

[0060] It should be noted that since the third expansion space 6 is located between two adjacent battery cells 11 along the first direction X, it is necessary to provide an expansion space for the two adjacent battery cells 11 to reduce the extrusion force between the two adjacent battery cells 11. And the battery cells 11 at both ends of the battery pack 1 along the first direction X are connected to the end plates. Correspondingly, the first expansion space 4 and the second expansion space 5 only need to provide an expansion space for one battery cell 11. Therefore, in the present application, the size of the third expansion space 6 along the first direction X is set to be larger than the size of the second expansion space 5 along the first direction X, which is larger than the size of the first expansion space 4 along the first direction X. This can not only ensure that the battery cell 11 has a certain expansion space, but also avoid the first expansion space 4 and the second expansion space 5 being too large and occupying too much space inside the battery pack, which is beneficial to improving the battery energy density and can ensure the safety and service life of the battery pack.

[0061] Furthermore, in some embodiments, along the first direction X, it satisfies: 0<L1≤L0 / 2; L1<L2≤2L1.

[0062] In the embodiment of the present application, since the third expansion space 6 is used to provide an expansion space for two adjacent battery cells 11, its size is relatively large correspondingly and can meet the expansion requirements of the battery cells 11 in the battery pack. Therefore, the present application preferably sets the size of the first expansion space 4 to be less than or equal to one-half of the size of the third expansion space 6, and correspondingly, it can meet the expansion requirements of one battery cell 11. At the same time, since the battery cell 11 in the middle not only expands by itself, but may also be subjected to the extrusion force generated by the expansion and deformation of the adjacent battery cells 11, the side of the squeezed battery cell 11 opposite to the squeezed side will further deform to buffer and absorb the expansion force in the battery cell 11. Therefore, the size of the third expansion space 6 is relatively large. At the same time, the battery cell 11 in the middle of the battery pack 1 has a higher possibility of expanding than the battery cell 11 at the end. Therefore, the present application sets the size of the first expansion space 4 to be less than or equal to one-half of the size of the third expansion space 6, which can not only meet the requirement of absorbing the expansion force of each battery cell 11 in the battery pack 1, but also effectively save the internal space of the battery pack and the material usage cost, and is beneficial to improving the volume energy density of the battery pack while ensuring the service life of the battery pack. At the same time, if the first expansion space 4 is not sufficient to completely absorb the expansion of the battery cell 11, the first end plate 2 can also deform in a direction away from the battery cell 11 to further absorb the expansion force of the battery cell 11.

[0063] Further, in the embodiment of the present application, L1 < L2 ≤ 2L1, combined with 0 < L1 ≤ L0 / 2, which is equivalent to L1 < L2 ≤ L0. Similarly, the second expansion space 5 only needs to provide an expansion space for one battery cell 11. Therefore, the size of the second expansion space 5 along the first direction X can be set to be less than the size of the third expansion space 6 along the first direction X. However, since the second end plate 3 usually has a relatively large anti-deformation force against the deformation of the second end plate 3 under the corresponding working conditions, only the second expansion space 5 can be used to absorb the expansion force of the battery cell 11. Therefore, by setting the size of the second expansion space 5 along the first direction X to be greater than the size of the first expansion space 4 along the first direction X at the same time, more expansion force of the battery cell 11 can be absorbed by the second expansion space 5, thereby realizing the relative balance of the internal expansion forces of each battery cell 11 in the battery pack 1 and avoiding the situation that the battery cell 11 on the side of the second end plate 3 is squeezed due to insufficient expansion space and the internal expansion force cannot be absorbed, thus effectively improving the safety of the battery cells 11 in the battery pack and the service life of the battery pack.

[0064] In some embodiments, L0 satisfies: 0.35 < L0 < 0.9.

[0065] In the embodiments of the present application, under normal circumstances, the size of the third expansion space 6 between adjacent battery cells 11 in the battery pack along the third direction is controlled within the range of 0.35 to 0.9 mm, which can achieve a better effect of absorbing the expansion deformation of the battery cells 11 when the battery cells 11 in the battery pack expand, realize relatively balanced expansion forces between the battery cells 11 in the battery pack, and ensure the service life of the battery pack.

[0066] It should be noted that the larger the value of L0, the larger the size of the corresponding third expansion space 6, and more expansion deformation of adjacent battery cells 11 can be absorbed. At this time, the sizes of the corresponding first expansion space 4 and second expansion space 5 are also larger, and more expansion deformation of the battery cells 11 located at both ends of the battery pack 1 along the first direction X can be absorbed, thereby ensuring the service life of the battery pack.

[0067] It should also be noted that in the embodiments of the present application, the value of L0 is within the range of 0.35 to 0.9, that is, this value can be any value among 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 or the range value between any two values.

[0068] It should also be noted that in the embodiments of the present application, the corresponding sizes L0, L1, and L2 can all be directly measured with a size measuring tool such as a ruler, vernier caliper, micrometer, etc.

[0069] As Figure 5 and Figure 6 As shown, in some embodiments, the first end plate 2 is provided with a first groove 21. The opening of the first groove 21 faces the battery cell 11 connected to the first end plate 2, and the first groove 21 forms the first expansion space 4; along the first direction X, the orthographic projection of the battery cell 11 on the first end plate 2 covers the first groove 21; on the side of the first end plate 2 facing the battery cell 11, the minimum distance between the notch edge of the first groove 21 and the outer edge of the first end plate 2 is L3 mm, satisfying: 5 ≤ L3 ≤ 15.

[0070] In the embodiments of the present application, by providing the first groove 21 on the first end plate 2, the first groove 21 faces the large surface of the battery cell 11 and is covered by the large surface of the battery cell 11, and the first groove 21 forms the first expansion space 4. At this time, when the battery cell 11 expands, it will expand and deform into the first groove 21 to absorb part of the expansion force of the battery cell 11.

[0071] It should be noted that since the size and shape of the battery cell 11 may vary in different embodiments, the shape of the first end plate 2 corresponds to the size of the large surface of the battery cell 11, and at the same time, the size of the first end plate 2 is not greater than the size of the large surface of the battery cell 11. In this application, by setting the minimum distance L3 between the notch edge of the first groove 21 and the outer edge of the first end plate 2 to satisfy: 5 ≤ L3 ≤ 15, at this time, both the thickness and structural strength of the edge of the first groove 21 of the first end plate 2 can be ensured, avoiding the fracture of the groove wall of the first groove 21, and at the same time, the energy absorption effect on the expansion of the battery cell 11 can be ensured, thereby ensuring the service life of the battery pack.

[0072] It should be noted that in the embodiments of this application, the value of L3 is in the range of 5 to 15, that is, this value can be any value among 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15 or the range value between any two values. When the value of L3 is less than 5, the structural strength of the groove wall of the first groove 21 will be insufficient, and it is easy to fracture during the long-term use of the battery pack. When the value of L3 is greater than 15, since the shape and size of the first end plate 2 correspond to the shape and size of the large surface of the battery cell 11, it is easy to cause the notch size of the first groove 21 to be insufficient, affecting the energy absorption effect on the expansion of the battery cell 11 and resulting in a decrease in the service life of the battery cell 11. Therefore, this application preferably sets the value of L3 in the range of 5 to 15.

[0073] It should also be noted that in the embodiments of this application, the corresponding dimension L3 can be directly measured with a dimension measuring tool such as a ruler, vernier caliper, micrometer, etc.

[0074] As Figure 7 and Figure 8 shown, in some embodiments, the second end plate 3 is provided with a second groove 31, the opening of the second groove 31 faces the battery cell 11 connected to the second end plate 3, and the second groove 31 forms a second expansion space 5; along the first direction X, the orthographic projection of the battery cell 11 on the second end plate 3 covers the second groove 31; on the side of the second end plate 3 facing the battery cell 11, there is a minimum distance L4 mm between the notch edge of the second groove 31 and the outer edge of the second end plate 3, satisfying: 5 ≤ L4 ≤ 15.

[0075] In the embodiments of this application, by providing the second groove 31 on the second end plate 3, the second groove 31 faces the large surface of the battery cell 11 and is covered by the large surface of the battery cell 11, and the second groove 31 forms a second expansion space 5. At this time, when the battery cell 11 expands, it will expand and deform into the second groove 31 to absorb part of the expansion force of the battery cell 11.

[0076] It should be noted that since the sizes and shapes of the battery cells 11 may vary in different embodiments, the shape of the second end plate 3 corresponds to the size of the large surface of the battery cell 11, and at the same time, the size of the second end plate 3 is not greater than the size of the large surface of the battery cell 11. In this application, by setting the minimum distance L4 between the notch edge of the second groove 31 and the outer edge of the second end plate 3 to satisfy: 5 ≤ L4 ≤ 15, at this time, both the thickness and structural strength of the edge of the second groove 31 of the second end plate 3 can be ensured, avoiding the fracture of the groove wall of the second groove 31, and at the same time, the energy absorption effect on the expansion of the battery cell 11 can be ensured, thereby ensuring the service life of the battery pack.

[0077] It should be noted that in the embodiments of this application, the value of L4 is within the range of 5 to 15, that is, this value can be any value within 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15 or the range value between any two values. When the value of L4 is less than 5, the structural strength of the groove wall of the second groove 31 will be insufficient and it is easy to break during the long-term use of the battery pack. When the value of L4 is greater than 15, since the shape and size of the second end plate 3 correspond to the shape and size of the large surface of the battery cell 11, it is easy to cause the notch size of the second groove 31 to be insufficient, affecting the energy absorption effect on the expansion of the battery cell 11 and resulting in a decrease in the service life of the battery cell 11. Therefore, this application preferably sets the value of L4 within the range of 5 to 15.

[0078] It should also be noted that in the embodiments of this application, the corresponding dimension L4 can be directly measured with a dimension measuring tool such as a ruler, vernier caliper, micrometer, etc.

[0079] As Figure 9 and Figure 10 shown, in some embodiments, a separator 7 is further included. The separator 7 is disposed between two adjacent battery cells 11 and is connected to the two adjacent battery cells 11; the separator 7 is provided with a through hole 71. The through hole 71 is disposed opposite to the side surfaces of the two adjacent battery cells 11 along the first direction X, and the through hole 71 forms a third expansion space 6; there is a minimum distance L5 mm between the hole wall of the through hole 71 and the outer edge of the separator 7, satisfying: 5 ≤ L5 ≤ 15.

[0080] In the embodiments of this application, by providing the through hole 71 in the separator 7, the through hole 71 is opposite to the large surfaces of the battery cells 11 on both sides of the separator 7 and is covered by the large surfaces of the battery cells 11 on both sides to form a third expansion space 6. At this time, when the battery cell 11 expands, it will expand and deform into the through hole 71 to absorb part of the expansion force of the battery cell 11.

[0081] It should be noted that since the size and shape of the battery cell 11 may vary in different embodiments, the shape of the separator 7 corresponds to the size of the large surface of the battery cell 11, and at the same time, the size of the separator 7 is not greater than the size of the large surface of the battery cell 11, which facilitates the assembly of the battery pack and avoids the occupation of invalid volume inside the battery pack. In this application, the minimum distance L5 between the hole wall of the through hole 71 and the outer edge of the separator 7 satisfies: 5 ≤ L5 ≤ 15. At this time, both the thickness and structural strength of the through hole 71 of the separator 7 can be ensured, the outer frame of the separator 7 (i.e., the hole wall of the through hole 71) can be prevented from breaking, and at the same time, the energy absorption effect on the expansion of the battery cell 11 can be ensured, thereby ensuring the service life of the battery pack.

[0082] It should be noted that in the embodiments of this application, the value of L5 is in the range of 5 to 15, that is, this value can be any value in 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15 or the range value between any two values. When the value of L5 is less than 5, the structural strength of the outer frame of the separator 7 will be insufficient and it is easy to break during the long-term use of the battery pack. When the value of L5 is greater than 15, since the shape and size of the separator 7 correspond to the shape and size of the large surface of the battery cell 11, it is easy to cause the insufficient size of the through hole 71, affecting the energy absorption effect on the expansion of the battery cell 11 and resulting in a decrease in the service life of the battery cell 11. Therefore, this application preferably sets the value of L5 in the range of 5 to 15.

[0083] It should also be noted that in the embodiments of this application, the corresponding size L5 can be directly measured with a size measuring tool such as a ruler, vernier caliper, micrometer, etc.

[0084] Furthermore, in some embodiments, on the basis of the width dimension range provided in the above embodiments, along the first direction X, the connection area between the first end plate 2 and the battery cell 11 close to it is S1 mm2, the connection area between the second end plate 3 and the battery cell 11 close to it is S2 mm2, and the connection area between the separator 7 and the battery cell 11 close to it is S3 mm2, satisfying: S1 = S2 = S3.

[0085] In the embodiments of this application, the contact areas of the battery cell 11 with the separator 7, the first end plate 2, and the second end plate 3 are the same. Correspondingly, it can ensure that the force conditions on the edges of the battery cells 11 at both ends of the battery pack 1 along the first direction X are the same as those of the battery cells 11 in the middle of the battery pack 1, ensuring the force uniformity and at the same time ensuring the consistency of the expansion area. It avoids the uneven local battery force caused by different expansion space areas and affects the safety of the battery cell 11.

[0086] In some embodiments, the separator 7 is a flexible energy-absorbing member. This can further improve the buffering and energy-absorbing effect between two adjacent battery cells 11, and further improve the safety and service life of the battery pack.

[0087] As Figure 1 and Figure 2 As shown, in some embodiments, the battery pack has a second direction Y intersecting the first direction X. The battery pack includes two side plates 8 spaced along the second direction Y. The two side plates 8 are oppositely arranged on both sides of the battery pack 1 along the second direction Y and are respectively connected to each battery cell 11 of the battery pack 1.

[0088] In the embodiments of the present application, by providing two side plates 8, the positions of multiple battery cells 11 in the battery pack 1 can be adhesively fixed along the second direction Y, ensuring the stability of the battery cells 11 fixed in the battery pack, thereby improving the safety and service life of the battery pack.

[0089] It should be noted that the first end plate 2, the second end plate 3 and the side plate 8 of the present application can be made of plastic material or metal material. When made of metal material, it needs to be insulated, such as spraying an insulating material on the surface or covering an insulating film.

[0090] As Figures 11-14 As shown, in some embodiments, it includes a first plate body 9, a second plate body 10 and multiple battery packs 1. At least two of the multiple battery packs 1 are spaced along the first direction X. The first plate body 9 extends along the second direction Y and is arranged between two adjacent battery packs 1 along the first direction X. The second end plate 3 is arranged between the first plate body 9 and the battery pack 1; the second plate body 10 extends along the second direction Y and is arranged on the side of the battery pack 1 away from the first plate body 9; along the first direction X, the first end plate 2 is arranged between the second plate body 10 and the battery pack 1; wherein, along the first direction X, the size of the first plate body 9 is L6 mm, and the size of the second plate body 10 is L7 mm, satisfying: L6 > L7.

[0091] In the embodiments of the present application, the battery pack includes multiple battery packs 1 arranged in an array, and at least two battery packs 1 are spaced along the first direction X. At the same time, the thicker first plate body 9 is arranged between two battery packs 1 spaced along the first direction X, and the thinner second plate body 10 is arranged on the side of the battery pack 1 away from the first plate body 9. At the same time, the second end plate 3 is arranged between the first plate body 9 and the battery pack 1, and the first end plate 2 is arranged between the second plate body 10 and the battery pack 1. Such a structure setting can ensure the balance of the expansion force of the battery cells 11 in the battery pack, thereby improving the safety of the battery pack and ensuring the service life of the battery pack.

[0092] Specifically, the first plate body 9 is relatively thick, and at this time, the first plate body 9 has a relatively high structural strength and is relatively difficult to deform; the second plate body 10 is relatively thin, and the corresponding structural strength is relatively low, making it prone to deformation. In a specific embodiment, the first plate body 9 can be arranged in the middle of the battery pack box body, equivalent to an intermediate crossbeam, and its function is to ensure the stability of the internal structure of the battery pack box body and provide a good supporting effect. Therefore, battery packs 1 are arranged on both sides of the corresponding first plate body 9, and a second end plate 3 is arranged between the battery pack 1 and the first plate body 9. The second end plate 3 is respectively connected to the battery cell 11 and the first plate body 9. When the battery cell 11 connected to the second end plate 3 expands, or the battery cells 11 in the battery pack 1 expand and deform and transmit the expansion and deformation to the battery cell 11 connected to the second end plate 3, the battery cell 11 connected to the second end plate 3 preferentially expands and deforms into the second groove 31 and presses against the second end plate 3. Since the second end plate 3 is resisted by the first plate body 9, there is an anti-deformation force that inhibits the deformation of the second end plate 3, and the second end plate 3 cannot deform away from the battery cell 11 to absorb the expansion force of the battery cell 11. Therefore, the size of the corresponding second expansion space 5 is set relatively large to absorb the relatively large expansion force of the battery cell 11. The second plate body 10 is relatively thin and is arranged on the side of the battery pack 1 away from the first plate body 9. The first end plate 2 is arranged between the second plate body 10 and the battery pack 1 and is respectively connected to the second plate body 10 and the battery cell 11. When the battery cell 11 connected to the first end plate 2 expands, or some of the battery cells 11 in the battery pack 1 expand and transmit the expansion and deformation to the battery cell 11 connected to the first end plate 2, the battery cell 11 connected to the first end plate 2 preferentially expands and deforms into the first groove 21 and presses against the first end plate 2. When the expansion force of the battery cell 11 is relatively small, the first expansion space 4 formed by the first groove 21 can be used to absorb the expansion force; when the expansion force of the battery cell 11 is relatively large, the expansion of the battery cell 11 will press against the first end plate 2. Since the second plate body 10 is relatively thin, although the second plate body 10 can also provide a certain anti-deformation force, it can also deform away from the battery cell 11 to absorb the expansion force without affecting the overall structural stability of the battery pack. Therefore, the corresponding first expansion space 4 can be set relatively smaller than the second expansion space 5 to reduce the volume and material usage of the battery pack and improve the volume energy density of the battery pack. At the same time, it can ensure that the expansion force of the battery cells 11 in the battery pack is well absorbed and buffered, achieve relatively balanced expansion forces of the battery cells 11 in the battery pack, and improve the safety and service life of the battery pack.

[0093] It should be noted that in a specific embodiment, foam or potting glue can also be filled between the first end plate 2 and the second plate body 10, and between the second end plate 3 and the first plate body 9 to further protect the battery pack 1.

[0094] The following provides some embodiments and comparative examples of the battery pack of the present application, and the present application will be described in more detail through specific embodiments and comparative examples. It can be seen from the following embodiments and comparative examples that in actual implementation, when the battery pack satisfies the relational expression of the present application, the forces on the battery cells 11 at both ends of the battery pack 1 along the first direction X are relatively balanced, the expansion forces are relatively small, and the safety performance is in a preferred state, which can ensure that the battery pack has a longer service life.

[0095]

[0096]

[0097] The simulation experiment method of the above embodiment is as follows: Fix the four corners of the battery cell 11, assign the measured expansion amount data at the last stage of the usage cycle of the battery cell 11 to all the batteries as the expansion amount, and extract the stress on the large surface of the battery, which is the expansion force of the battery cell 11. It can be seen from the above embodiments and comparative examples that by comparing the magnitudes of the expansion forces received by the battery cells 11 at both ends, when the first expansion space 4 and the second expansion space 5 satisfy L2 > L1 > 0, the expansion forces received by the battery cells 11 at both ends can be balanced, thereby better extending the service life of the battery. Further, when the values of the first expansion space 4, the second expansion space 5, and the third expansion space 6 satisfy 0 < L1 ≤ L0 / 2; L1 < L2 ≤ 2L1, the difference in the expansion forces received by the batteries on both sides is relatively small, and the service life of the battery can be better extended.

[0098] Correspondingly, an electrical device according to an embodiment of the present application includes a battery pack as described in any one of the foregoing embodiments.

[0099] It can be understood that the electrical device according to the embodiment of the present application can have all the technical features and corresponding beneficial effects of the above battery pack, which will not be elaborated herein.

[0100] It should be noted that the electrical device referred to in the present application may include, but is not limited to, a backup power supply, an electrode, an electric vehicle, an electric bicycle, an electric motorcycle, a large battery, etc.

[0101] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0102] The above has introduced in detail a battery pack and an electrical device provided by an embodiment of the present application, and specific examples have been used to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; 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: Having a first direction (X), comprising: A plurality of battery cells (11) are arranged along the first direction (X) to form a battery pack (1); A first end plate (2) is arranged on one side of the battery pack (1) along the first direction (X), and a first expansion space (4) is provided between the first end plate (2) and the battery cell (11) adjacent thereto; A second end plate (3) is arranged at the other side of the battery pack (1) along the first direction (X), and a second expansion space (5) is provided between the second end plate (3) and the battery cell (11) adjacent thereto; Wherein, along the first direction (X), the size of the first expansion space (4) is L1 mm, and the size of the second expansion space (5) is L2 mm, satisfying: L2>L1>0.

2. The battery pack according to claim 1, characterized in that: Along the first direction (X), a third expansion space (6) is provided between two adjacent battery cells (11), and the size of the third expansion space (6) is L0 mm, satisfying: L0≥L2>L1>0.

3. The battery pack according to claim 2, characterized in that: Along the first direction (X), it satisfies: 0<L1≤L0 / 2; L1<L2≤2L1.

4. The battery pack according to claim 3, characterized in that: L0 satisfied: 0.35 <L0<0.9。 5. The battery pack according to any one of claims 2 to 4, characterized in that: The first end plate (2) is provided with a first groove (21), the opening of the first groove (21) faces the battery cell (11) connected to the first end plate (2), and the first groove (21) forms the first expansion space (4); along the first direction (X), the orthographic projection of the battery cell (11) on the first end plate (2) covers the first groove (21); On the side of the first end plate (2) facing the battery cell (11), there is a minimum distance L3 mm between the notch edge of the first groove (21) and the outer edge of the first end plate (2), satisfying: 5≤L3≤15.

6. The battery pack according to claim 5, characterized in that: The second end plate (3) is provided with a second groove (31), the opening of the second groove (31) faces the battery cell (11) connected to the second end plate (3), and the second groove (31) forms the second expansion space (5); along the first direction (X), the orthographic projection of the battery cell (11) on the second end plate (3) covers the second groove (31); On the side of the second end plate (3) facing the battery cell (11), there is a minimum distance L4 mm between the notch edge of the second groove (31) and the outer edge of the second end plate (3), satisfying: 5≤L4≤15.

7. The battery pack according to claim 6, characterized in that: The invention also comprises a separator (7), wherein the separator (7) is arranged between two adjacent battery cells (11) and connected to the two adjacent battery cells (11); the separator (7) is provided with a through hole (71), wherein the through hole (71) is arranged opposite to the side surfaces of the two adjacent battery cells (11) along the first direction (X), and the through hole (71) forms the third expansion space (6); and there is a minimum distance L5 mm between the hole wall of the through hole (71) and the outer edge of the separator (7), satisfying the following: 5≤L5≤15.

8. The battery pack according to claim 7, characterized in that: Along the first direction (X), the connection area between the first end plate (2) and the battery cell (11) adjacent thereto is S1 mm 2 The connection area between the second end plate (3) and the battery cell (11) adjacent thereto is S2 mm 2 The connection area between the separator (7) and the battery cell (11) adjacent thereto is S3 mm 2 ,satisfy: S1=S2=S3.

9. The battery pack according to claim 7, characterized in that: The partition (7) is a flexible energy absorbing member.

10. The battery pack according to claim 1, characterized in that: The battery pack has a second direction (Y) intersecting the first direction (X), and comprises two side plates (8) arranged at intervals along the second direction (Y). The two side plates (8) are arranged oppositely on two sides of the battery pack (1) along the second direction (Y), and are respectively connected to each of the battery cells (11) of the battery pack (1).

11. The battery pack according to claim 10, characterized in that: include: A plurality of the battery packs (1), wherein two of the battery packs (1) are arranged at intervals along the first direction (X); A first plate (9) extending along the second direction (Y) and arranged between two adjacent battery groups (1) along the first direction (X); and the second end plate (3) is arranged between the first plate (9) and the battery group (1); A second plate (10) extends along the second direction (Y) and is arranged on a side of the battery pack (1) away from the first plate (9); along the first direction (X), the first end plate (2) is arranged between the second plate (10) and the battery pack (1); Wherein, along the first direction (X), the size of the first plate body (9) is L6 mm, and the size of the second plate body (10) is L7 mm, satisfying: L6>L7.

12. An electrical device, characterized in that: Comprising a battery pack as described in any one of claims 1-11.

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