Box body structure of battery pack and battery pack

Abstract

The utility model provides a box body structure of a battery pack and the battery pack, the box body structure comprises a bottom plate, two oppositely-arranged cross beams and two oppositely-arranged longitudinal beams, the bottom plate, the two cross beams and the two longitudinal beams define a containing space, and a buffer layer and a reinforcing plate are sequentially arranged on the side, close to the containing space, of each longitudinal beam; the reinforcing plate, the buffer layer and the longitudinal beam jointly form an energy absorption layer, and the energy absorption layer is configured to deform to absorb collision energy when being collided, so that when the box body structure is subjected to side collision (namely collision perpendicular to the plane where the longitudinal beam is located), the energy absorption layer deforms under extrusion of side collision, the deformation can absorb the collision energy, and the collision energy can be absorbed. And the collision force reaching the side surface of the battery cell stack body is greatly reduced, so that the effect of protecting the battery cells is achieved, and the side surface collision safety of the battery cells is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and particularly relates to a battery pack box structure and a battery pack. BACKGROUND

[0002] Most of the existing battery pack boxes are provided with multiple middle beams to improve the side extrusion resistance of the battery pack. The middle beams can increase the side crash resistance, so the side crash safety of the battery cell close to the middle beam is higher, and the side crash safety of the battery cell far from the middle beam is poor, which leads to inconsistent side crash safety of each battery cell and affects the overall safety of the battery pack. Therefore, how to uniformly improve the side crash safety of all battery cells is a problem to be solved. CONTENT OF THE UTILITY MODEL

[0003] Therefore, the present application aims to provide a battery pack box structure and a battery pack to solve or partially solve the problems in the background art.

[0004] To achieve the above purpose, the first aspect of the present application provides a battery pack box structure, which comprises a bottom plate, two oppositely arranged beams and two oppositely arranged longitudinal beams. The bottom plate, the two beams and the two longitudinal beams jointly form a containing space for containing a battery cell stack. The side of the longitudinal beam close to the containing space is sequentially provided with a buffer layer and a reinforcing plate. The reinforcing plate, the buffer layer and the longitudinal beam jointly form an energy absorption layer configured to deform to absorb collision energy when subjected to a collision.

[0005] Optionally, the reinforcing plate is rigidly connected with the longitudinal beam, and the reinforcing plate comprises a connecting portion rigidly connected with the longitudinal beam. The connecting portion comprises a weak sub-portion configured to break when the energy absorption layer is subjected to a collision greater than or equal to a preset collision intensity.

[0006] Optionally, the reinforcing plate comprises a main body portion arranged along a first direction and the connecting portion arranged along a second direction. The first direction is the height direction of the box structure, and the second direction is the extension direction of the beam. The connecting portion comprises a first sub-portion, the weak sub-portion and a second sub-portion connected in sequence. The size of the orthographic projection of the first sub-portion in the first direction and the size of the orthographic projection of the second sub-portion in the first direction are both greater than the size of the orthographic projection of the weak sub-portion in the first direction.

[0007] Optionally, the reinforcing plate comprises a connecting portion, and the connecting portion and the longitudinal beam are both connected with the buffer layer, and the connecting portion does not contact the longitudinal beam.

[0008] Optionally, the reinforcing plate comprises a main body portion arranged along a first direction, the main body portion comprises at least one support sub-portion for supporting a side surface of the cell stack, the first direction is a height direction of the box structure, and a ratio of a sum of sizes of orthographic projections of all the support sub-portions in the first direction to a size of an orthographic projection of the longitudinal beam in the first direction is greater than or equal to 1:2.

[0009] Optionally, the main body portion further comprises a protruding sub-portion protruding towards a side close to the buffer layer, a ratio of a size of an orthographic projection of the protruding sub-portion in a second direction to a size of an orthographic projection of the buffer layer in the second direction is greater than 0.5:10 and less than or equal to 3:10, and the second direction is an extension direction of the cross beam.

[0010] Optionally, the main body portion comprises two support sub-portions, and the protruding sub-portion is located between the two support sub-portions.

[0011] Optionally, the main body portion further comprises an inclined sub-portion, the inclined sub-portion comprises a free end and a fixed end, the free end is arranged in a spaced manner with the longitudinal beam, and the fixed end is connected with the support sub-portion, a distance between the free end and the longitudinal beam is less than a distance between the fixed end and the longitudinal beam.

[0012] Optionally, a thickness of the main body portion in a second direction is 0.8-15 mm, and the second direction is the extension direction of the cross beam.

[0013] Optionally, the longitudinal beam comprises a longitudinal beam main body and a protruding portion, the protruding portion is located on a side of the longitudinal beam main body away from the accommodation space, the longitudinal beam main body comprises a support portion and a recessed portion, and a distance between the support portion and the main body portion is less than a distance between the recessed portion and the main body portion.

[0014] Optionally, a ratio of a size of an orthographic projection of the buffer layer in a first direction to a size of an orthographic projection of the longitudinal beam in the first direction is greater than or equal to 1:2, and a thickness of the buffer layer in a second direction is 5-30 mm, the first direction is the height direction of the box structure, and the second direction is the extension direction of the cross beam.

[0015] Optionally, the buffer layer is a foamed adhesive layer, a foam layer and / or a foamed aluminum layer.

[0016] The second aspect of the present application provides a battery pack, comprising the box structure of any one of the first aspect, and a cell stack is arranged in the accommodation space of the box structure.

[0017] It can be seen from the above that the battery pack provided by the application has the box structure and the battery pack, the box structure comprises a bottom plate, two beams arranged oppositely and two longitudinal beams arranged oppositely, the bottom plate, the two beams and the two longitudinal beams enclose a containing space, the longitudinal beam close to one side of the containing space is sequentially provided with a buffer layer and a reinforcing plate, the reinforcing plate, the buffer layer and the longitudinal beam jointly constitute an energy absorption layer, the energy absorption layer is configured to deform to absorb collision energy when subjected to a collision, thus, when the box structure is subjected to a side collision (i.e. a collision perpendicular to the plane where the longitudinal beam is located), the energy absorption layer deforms under the extrusion of the side collision, and this part of deformation can absorb the collision energy, so that the collision force reaching the side of the cell stack is greatly reduced, thereby playing a role in protecting the cell and improving the side collision safety of the cell. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0019] Figure 1 A top view of the box structure of the battery pack of the embodiment of the present application is shown;

[0020] Figure 2 A first cross-sectional view of the box structure of the embodiment of the present application in the B-B section is shown; Figure 1 A partial enlarged view of A in the above figure is shown;

[0021] Figure 3 A second cross-sectional view of the box structure of the embodiment of the present application in the B-B section is shown;

[0022] Figure 4 A partial enlarged view of C in the above figure is shown; Figure 3

[0023] A third cross-sectional view of the box structure of the embodiment of the present application in the B-B section is shown; Figure 5 Figure 4 A partial enlarged view of D in the above figure is shown;

[0024] Figure 6 A fourth cross-sectional view of the box structure of the embodiment of the present application in the B-B section is shown;

[0025] Figure 7 A partial enlarged view of E in the above figure is shown; Figure 6

[0026] A partial enlarged view of F in the above figure is shown. Figure 8 Figure 7

[0027] ​​​In the figure: 1, box structure; 11, cross beam; 12, energy absorption layer; 121, longitudinal beam; 1211, longitudinal beam main body; 12111, support part; 12112, inward part; 1212, protruding part; 122, buffer layer; 123, reinforcing plate; 1231, main part; 12311, support subpart; 12312, protruding subpart; 12313, inclined subpart; 123131, free end; 123132, fixed end; 1232, connecting part; 12321, first subpart; 12322, weak subpart; 12323, second subpart; 13, bottom plate. DETAILED DESCRIPTION

[0028] To make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the embodiments and the accompanying drawings.

[0029] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the common meanings understood by those with ordinary skills in the art to which the present application belongs. The terms "first", "second" and similar terms used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, without excluding other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0030] Most of the existing battery pack boxes are provided with multiple middle cross beams to improve the side extrusion resistance of the battery pack. The middle cross beams can increase the side crash performance, so the side crash safety of the battery cells close to the middle cross beams is higher, and the side crash safety of the battery cells far from the middle cross beams is poor, which leads to inconsistent side crash safety of each battery cell, affecting the overall safety of the battery pack.

[0031] If the side collision safety of all the battery cells inside the battery pack is to be improved, many middle crossbeams need to be arranged. However, due to the limitation of the overall size of the battery pack, the number of middle crossbeams arranged is usually kept at 1-5, and the number of middle crossbeams arranged cannot be increased unlimitedly. Therefore, in order to ensure that the battery cells far away from the middle crossbeams are not subjected to local extrusion, a gap needs to be reserved between the battery cells on the two side edges of the battery pack and the longitudinal beams of the battery pack, so as to avoid the problem that the battery cells are subjected to excessive local force during side collision extrusion. In addition, the battery cells can also be better protected by increasing the number of middle crossbeams to reduce the distance between the crossbeams, or increasing the reserved gap between the battery cells and the longitudinal beams.

[0032] However, both of the above two ways will result in low utilization of the internal space of the box, and only the position of the middle crossbeam is supported during side collision, and the rigidity of other areas is low, the energy absorption is weak, and the battery cells are prone to excessive local force, which finally leads to inconsistent side collision safety of each battery cell.

[0033] Therefore, how to uniformly support and protect each battery cell in the box without reducing the utilization of the internal space of the box and improve the side collision safety of all the battery cells is a problem to be solved.

[0034] Based on this, the application provides a battery pack and a box structure of the battery pack. Figure 1 A top view of the box structure of the battery pack of the embodiment of the application is shown, Figure 2 A partial enlarged view of the middle A is shown. Figure 1

[0035] Referring to Figure 1 and Figure 2 As shown, the box structure 1 of the battery pack includes a bottom plate 13, two oppositely arranged crossbeams 11 and two oppositely arranged longitudinal beams 121. The bottom plate 13, the two crossbeams 11 and the two longitudinal beams 121 form a containing space, and the containing space is used to contain a battery cell stack. The side of the longitudinal beam 121 close to the containing space is sequentially provided with a buffer layer 122 and a reinforcing plate 123. The reinforcing plate 123, the buffer layer 122 and the longitudinal beam 121 together constitute an energy absorption layer 12, which is configured to deform to absorb collision energy when subjected to collision.

[0036] Specifically, the bottom plate 13, the two crossbeams 11 and the two longitudinal beams 121 form a containing space, and the containing space is used to contain a battery cell stack. The battery pack can be used for a vehicle. When the battery pack is used for a vehicle, the arrangement direction of the longitudinal beam 121 can be the length direction of the vehicle, and the arrangement direction of the crossbeam 11 can be the width direction of the vehicle.

[0037] ​A buffer layer 122 and a reinforcing plate 123 are sequentially arranged on the side of the longitudinal beam 121 near the storage space. In other words, the reinforcing plate 123 is positioned close to the storage space. In practice, the reinforcing plate 123 can directly contact the side of the battery cell stack within the storage space, or a buffer gap can be left between the sides of the battery cell stack.

[0038] The reinforcing plate 123, the buffer layer 122 and the longitudinal beam 121 together constitute the energy-absorbing layer 12. The energy-absorbing layer 12 is configured to deform when subjected to a collision to absorb the collision energy. In this way, when the box structure 1 is subjected to a side collision (i.e., a collision perpendicular to the plane where the longitudinal beam 121 is located), the energy-absorbing layer 12 is deformed under the extrusion of the side collision. This part of the deformation can absorb the collision energy, thereby greatly reducing the collision force reaching the side of the battery cell stack, thereby playing a role in protecting the battery cells and improving the side collision safety of the battery cells.

[0039] In addition, since the entire longitudinal beam 121 is sequentially provided with a buffer layer 122 and a reinforcement plate 123 on the side close to the accommodating space, the reinforcement plate 123, the buffer layer 122 and the longitudinal beam 121 together constitute the energy absorption layer 12. Therefore, the energy absorption layer 12 can provide uniform protection and anti-collision effects on the sides of all battery cells, uniformly improving the side collision safety of all battery cells, and avoiding the problem of insufficient support in the area without cross beams of the traditional box, which causes the battery cells to be easily subjected to local excessive force.

[0040] At the same time, because the energy-absorbing layer 12 can provide uniform protection and collision protection for the sides of all battery cells, the present box structure 1 can be provided with no intermediate crossbeams, or the number of intermediate crossbeams can be reduced. The reduced number of intermediate crossbeams can free up space within the box structure 1, thereby improving the space utilization of the entire battery pack. Furthermore, in a specific implementation of the present box structure 1, the reserved gap between the sides of the battery cell stack and the reinforcement plate 123 can be reduced or eliminated, thereby further improving the space utilization of the entire battery pack.

[0041] Figure 3 A first cross-sectional schematic diagram of the box structure 1 of the embodiment of the present application on the BB section is shown. Figure 4 Shown Figure 3 A partial enlarged schematic diagram of C in the middle. Figure 5 Shown Figure 4 A partial enlarged schematic diagram of D in the middle.

[0042] In some embodiments, see Figure 3 、 Figure 4 and Figure 5As shown, the reinforcing plate 123 is rigidly connected with the longitudinal beam 121, the reinforcing plate 123 comprises a connecting portion 1232 rigidly connected with the longitudinal beam 121, the connecting portion 1232 comprises a weak sub-portion 12322 configured to be broken when the energy-absorbing layer 12 is subjected to a collision with a strength greater than or equal to a preset collision strength.

[0043] Specifically, the rigid connection of the reinforcing plate 123 with the longitudinal beam 121 can mean that the reinforcing plate 123 is welded with the longitudinal beam 121, or can mean that the reinforcing plate 123 and the longitudinal beam 121 are integrally formed.

[0044] When the reinforcing plate 123 is rigidly connected with the longitudinal beam 121, the connecting position of the reinforcing plate 123 and the longitudinal beam 121 cannot be deformed even when subjected to a collision and extrusion, and therefore, in order to ensure that the energy-absorbing layer 12 has an effective energy-absorbing effect, in the present application, the connecting portion 1232 comprises a weak sub-portion 12322 configured to be broken when the energy-absorbing layer 12 is subjected to a collision with a strength greater than or equal to a preset collision strength, so that when the box structure 1 is subjected to a collision with a strength greater than or equal to the preset collision strength, the weak sub-portion 12322 is broken, more energy-absorbing space is released, the energy-absorbing layer 12 can have a good energy-absorbing effect, and the collision force reaching the side of the battery cell stack is greatly reduced, thereby protecting the battery cell and improving the side collision safety of the battery cell.

[0045] For example, the preset collision strength can be 50 kN or 45 kN, etc.

[0046] In specific implementation, when the inside of the reinforcing plate 123 is supported by a rigid wall and a 150 mm diameter cylinder is extruded vertically to the longitudinal beam 121 from the outside of the longitudinal beam 121, the weak sub-portion 12322 is required to withstand a load of less than 50 kN, and the weak sub-portion 12322 is damaged to release the energy-absorbing space when the load exceeds the load.

[0047] In some embodiments, continuing to refer to Figure 3 , Figure 4 and Figure 5 As shown, the reinforcing plate 123 comprises a main body portion 1231 arranged along a first direction (i.e., the direction indicated by W in Figure 3 ) and a connecting portion 1232 arranged along a second direction (i.e., the direction indicated by Q in Figure 3 ), the first direction is the height direction of the box structure 1, and the second direction is the extension direction of the cross beam 11, the connecting portion 1232 comprises a first sub-portion 12321, a weak sub-portion 12322 and a second sub-portion 12323 connected in sequence, the size of the orthographic projection of the first sub-portion 12321 in the first direction and the size of the orthographic projection of the second sub-portion 12323 in the first direction are both greater than the size of the orthographic projection of the weak sub-portion 12322 in the first direction.

[0048] Specifically, the size of the orthographic projection of the first sub-part 12321 in the first direction and the size of the orthographic projection of the second sub-part 12323 in the first direction are both greater than the size of the orthographic projection of the weak sub-part 12322 in the first direction, that is, the thickness of the first sub-part 12321 and the second sub-part 12323 in the first direction are both greater than the thickness of the weak sub-part 12322, and the collision strength that the first sub-part 12321 and the second sub-part 12323 can withstand is greater than the collision strength that the weak sub-part 12322 can withstand. Therefore, when the energy absorption layer 12 is subjected to a collision greater than or equal to the preset collision strength, the weak sub-part 12322 breaks to release the energy absorption space, ensuring that the energy absorption layer 12 can effectively absorb energy. At the same time, the first sub-part 12321 and the second sub-part 12323 do not break to maintain the rigidity of the energy absorption layer 12, ensuring the structural strength of the overall energy absorption layer 12, and avoiding the overall energy absorption layer 12 from being broken to damage the battery cell stack in the accommodation space.

[0049] In the present application, by limiting the structure and size of the first sub-part 12321, the weak sub-part 12322 and the second sub-part 12323, the energy absorption effect and structural strength of the energy absorption layer 12 can be considered, and damage to the battery cell stack in the accommodation space can be avoided.

[0050] Figure 6 A second cross-sectional view of the box structure 1 of the embodiment of the present application in the B-B cross-section is shown, Figure 7 A second cross-sectional view of the box structure 1 of the embodiment of the present application in the B-B cross-section is shown, Figure 6 A second cross-sectional view of the box structure 1 of the embodiment of the present application in the B-B cross-section is shown, Figure 8 A second cross-sectional view of the box structure 1 of the embodiment of the present application in the B-B cross-section is shown, Figure 7 A second cross-sectional view of the box structure 1 of the embodiment of the present application in the B-B cross-section is shown.

[0051] In some embodiments, as shown in Figure 6 、 Figure 7 and Figure 8 , the reinforcing plate 123 includes a connecting part 1232, the connecting part 1232 and the longitudinal beam 121 are respectively connected with the buffer layer 122, and the connecting part 1232 is not in contact with the longitudinal beam 121.

[0052] Specifically, the connecting part 1232 is connected with the longitudinal beam 121 on the opposite two sides of the buffer layer 122, so that the connecting part 1232 and the longitudinal beam 121 are not in direct contact. When a side collision occurs, the non-contact connecting part 1232 and the longitudinal beam 121 will not limit the deformation of the entire energy absorption layer 12, and at this time the entire energy absorption layer 12 mainly relies on the deformation of the buffer layer 122 to achieve the energy absorption effect.

[0053] Exemplarily, as shown in Figure 8 , there can be a certain gap between the connecting part 1232 and the longitudinal beam 121 (such as Figure 8The gap can avoid the contact between the connecting part 1232 and the longitudinal beam 121 when the buffer layer 122 is deformed by the impact extrusion, so as to avoid affecting the energy absorption effect.

[0054] Further, the connecting mode between the connecting part 1232 and the longitudinal beam 121 and the buffer layer 122 can be adhesion, clamping or bolt connection and the like.

[0055] In some embodiments, continuing to refer to Figure 6 、 Figure 7 and Figure 8 As shown, the reinforcing plate 123 includes a main body part 1231 arranged along a first direction, the first direction being the height direction of the box structure 1, and the main body part 1231 includes at least one supporting sub-part 12311 for supporting the side surface of the battery cell stack, and the ratio of the sum of the sizes of the orthographic projections of all the supporting sub-parts 12311 in the first direction to the size of the orthographic projection of the longitudinal beam 121 in the first direction is greater than or equal to 1:2.

[0056] Specifically, the main body part 1231 includes at least one supporting sub-part 12311, and exemplarily, the main body part 1231 can be provided with one supporting sub-part 12311, or a plurality of supporting sub-parts 12311 can be arranged at intervals, and all the supporting sub-parts 12311 collectively support the side surface of the battery cell stack.

[0057] The side of the supporting sub-part 12311 close to the accommodating space can be a plane, so that the side of the supporting sub-part 12311 close to the side surface of the battery cell stack is a plane, so that even if the supporting sub-part 12311 directly contacts the side surface of the battery cell stack or extrudes the side surface of the battery cell stack under the action of the extrusion force when the energy absorption layer 12 is impacted, the plane arrangement will not cause damage to the side surface of the battery cell stack, ensuring the safety of the battery cell stack.

[0058] The ratio of the sum of the sizes of the orthographic projections of all the supporting sub-parts 12311 in the first direction to the size of the orthographic projection of the longitudinal beam 121 in the first direction is greater than or equal to 1:2, that is, the ratio of the sum of the heights of all the supporting sub-parts 12311 in the first direction to the height of the longitudinal beam 121 in the first direction is greater than or equal to 1:2, so that the heights of all the supporting sub-parts 12311 are sufficient to support the side surface of the battery cell stack.

[0059] If the ratio of the sum of the heights of all the supporting sub-parts 12311 to the height of the longitudinal beam 121 is less than 1:2, the sum of the heights of all the supporting sub-parts 12311 is too small to support the side surface of the battery cell stack, and the battery cell stack cannot be effectively protected.

[0060] Further, the ratio of the side area of all the support sub-sections 12311 close to the side of the battery cell stack to the side area of the battery cell stack is greater than or equal to 1:2, so as to ensure that all the support sub-sections 12311 can play a good supporting role on the side of the battery cell stack.

[0061] In some embodiments, continuing to refer to Figure 6 , Figure 7 and Figure 8 , the main body section 1231 further comprises a protruding sub-section 12312, which protrudes towards the side close to the buffer layer 122, and the ratio of the size of the orthographic projection of the protruding sub-section 12312 in the second direction to the size of the orthographic projection of the buffer layer 122 in the second direction (i.e. the direction indicated by Q in FIG. 12B) is greater than 0.5:10 and less than or equal to 3:10, and the second direction is the extending direction of the cross beam 11. Figure 6

[0062] Specifically, the protruding sub-section 12312 protrudes towards the side close to the buffer layer 122, so that when subjected to an impact from the outside, the impact force will first reach the protruding sub-section 12312 and then reach the support sub-section 12311 for the reinforcing plate 123, so that the protruding sub-section 12312 can further buffer the impact force to further reduce the impact force reaching the support sub-section 12311, thereby better protecting the battery cell stack.

[0063] The ratio of the size of the orthographic projection of the protruding sub-section 12312 in the second direction to the size of the orthographic projection of the buffer layer 122 in the second direction is greater than 0.5:10, so as to ensure that the protruding sub-section 12312 can effectively buffer the impact force. When the ratio is less than 0.5:10, the size of the protruding sub-section is too small to effectively buffer the impact force.

[0064] The ratio of the size of the orthographic projection of the protruding sub-section 12312 in the second direction to the size of the orthographic projection of the buffer layer 122 in the second direction is less than or equal to 3:10, so that the setting of the protruding sub-section 12312 will not affect the deformation of the buffer layer 122, and thus will not affect the energy absorption effect of the buffer layer 122. If the ratio is greater than 3:10, the size of the protruding sub-section 12312 is too large, so that the setting of the protruding sub-section 12312 occupies too much setting space of the buffer layer 122, reducing the deformation space of the buffer layer 122 when subjected to an impact, and thus reducing the energy absorption effect of the buffer layer 122.

[0065] In some embodiments, continuing to refer to Figure 6 , Figure 7 and Figure 8 ​As shown, the main body 1231 includes two support sub-sections 12311, and the protruding sub-section 12312 is located between the two support sub-sections 12311, so when impacted, the protruding sub-section 12312 in the middle is impacted first and plays a certain buffering role on the impact force, so that the impact force reaching the support sub-sections 12311 on both sides of the protruding sub-section 12312 is reduced, thereby well protecting the battery cell stack.

[0066] In some embodiments, continuing to refer to Figure 6 、 Figure 7 and Figure 8 As shown, the main body 1231 also includes an inclined sub-section 12313, which includes a free end 123131 and a fixed end 123132, the free end 123131 is arranged apart from the longitudinal beam 121, and the fixed end 123132 is connected with the support sub-section 12311, and the distance between the free end 123131 and the longitudinal beam 121 is less than the distance between the fixed end 123132 and the longitudinal beam 121.

[0067] Specifically, the free end 123131 of the inclined sub-section 12313 is not fixed, while the fixed end 123132 of the inclined sub-section 12313 is fixed, and the distance between the free end 123131 and the longitudinal beam 121 is less than the distance between the fixed end 123132 and the longitudinal beam 121, so that when impacted from the side, the free end 123131 is impacted first due to the smaller distance between the free end 123131 and the longitudinal beam 121, and after being impacted, the free end 123131 moves in the direction close to the battery cell stack under the action of the impact force, and in this process, the movement of the free end 123131 can buffer the impact force to further reduce the impact force reaching the support sub-section 12311, thereby better protecting the battery cell stack.

[0068] In some embodiments, the thickness of the main body 1231 in the second direction is 0.8-15mm, and the second direction is the extension direction of the cross beam 11, so that the strength of the main body 1231 can be ensured to ensure that the main body 1231 can well protect the battery cell stack.

[0069] For example, the thickness of the main body 1231 in the second direction can be 0.8mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc., which is not limited here.

[0070] In some embodiments, continuing to refer to Figure 6 、 Figure 7 and Figure 8As shown, the longitudinal beam 121 includes a longitudinal beam body 1211 and a protruding portion 1212. The protruding portion 1212 is located on the side of the longitudinal beam body 1211 away from the accommodating space. The longitudinal beam body 1211 includes a supporting portion 12111 and a recessed portion 12112. The distance between the supporting portion 12111 and the main body 1231 is smaller than the distance between the recessed portion 12112 and the main body 1231.

[0071] Specifically, the protruding portion 1212 is located on a side of the longitudinal beam body 1211 away from the accommodating space. Thus, when a side collision occurs, the protruding portion 1212 will be subjected to force first.

[0072] The longitudinal beam body 1211 includes a supporting portion 12111 and a recessed portion 12112. The distance between the supporting portion 12111 and the main body 1231 is smaller than the distance between the recessed portion 12112 and the main body 1231. In this way, since the distance between the recessed portion 12112 and the main body 1231 is larger, the recessed portion 12112 has more energy absorption space and can play a better energy absorption role.

[0073] The protrusion 1212 is perpendicular to the central axis of the plane where the longitudinal beam 121 is located (i.e. Figure 7 The inner recess 12112 is perpendicular to the central axis of the plane where the longitudinal beam 121 is located (ie Figure 7 The protrusion 1212 and the recessed portion 12112 can be located on a straight line, or the distance between their central axes can be less than or equal to a predetermined value. Thus, when the protrusion 1212 is first subjected to a side collision, the position of the recessed portion 12112, which can better absorb energy, coincides with the position of the protrusion 1212. Thus, the recessed portion 12112 can absorb the collision energy more directly and quickly, achieving a more effective energy absorption effect.

[0074] Furthermore, the protrusion 1212 is perpendicular to the central axis of the plane where the longitudinal beam 121 is located (i.e. Figure 7 1) and the raised sub-portion 12312 are perpendicular to the central axis of the plane where the longitudinal beam 121 is located (ie Figure 7 3) can be located on a straight line, or the distance between their central axes can be less than or equal to a predetermined value. Thus, when protrusion 1212 is first subjected to a side impact, the position of protruding sub-portion 12312 exactly corresponds to the position of protruding sub-portion 1212. Thus, protruding sub-portion 12312 can absorb the impact energy more directly and quickly, thereby providing a more effective buffering and energy absorption effect.

[0075] Furthermore, the longitudinal beam 121 may be made of extruded aluminum profiles, roll-welded steel profiles, or the like.

[0076] In some embodiments, the ratio of the size of the orthographic projection of the buffer layer 122 in the first direction to the size of the orthographic projection of the longitudinal beam 121 in the first direction is greater than or equal to 1:2, the thickness of the buffer layer 122 in the second direction is 5-30 mm, the first direction is the height direction of the box structure 1, and the second direction is the extension direction of the cross beam 11, so as to ensure that the thickness and height of the buffer layer 122 are sufficient to effectively buffer and absorb energy.

[0077] For example, the ratio of the size of the orthographic projection of the buffer layer 122 in the first direction to the size of the orthographic projection of the longitudinal beam 121 in the first direction can be 1:2, 1.5:2, 1:1, etc., which is not specifically limited here.

[0078] The thickness of the buffer layer 122 in the second direction can be 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, etc., which is not specifically limited here.

[0079] In some embodiments, the buffer layer 122 can be a foamed adhesive layer, a foam layer, and / or a foamed aluminum layer, so that the buffer layer 122 has a certain deformation capacity and can effectively absorb energy.

[0080] Further, when the buffer layer 122 is compressed to 10%, the equivalent average stress generated is not less than 2Mpa; when the buffer layer 122 is compressed to 50%, the equivalent average stress generated is not greater than 5Mpa, so as to ensure the buffering effect of the buffer layer 122.

[0081] The application also provides a battery pack comprising the box structure 1 of any of the above embodiments, and an electric core stack is arranged in the containing space of the box structure 1.

[0082] The battery pack of the application can effectively protect the electric core stack from all directions by arranging the energy-absorbing layer 12 in the box structure 1, and there is no problem of insufficient support in the area without the intermediate cross beam of the traditional box, and the box structure 1 can reduce the design of the intermediate cross beam and effectively reduce the gap between the electric core stack and the reinforcing plate 123, thereby improving the space utilization of the battery pack.

[0083] It should be understood by those skilled in the art that the above discussion of any of the embodiments is only exemplary and is not intended to limit the scope of the application (including the claims) to these examples; the technical features of the above embodiments or different embodiments can also be combined under the idea of the application, the steps can be implemented in any order, and there are many other changes of different aspects of the application as described above. In order to be brief, they are not provided in detail.

[0084] Embodiments of the application are intended to embrace all such alterations, modifications, and variations that fall within the broad scope of the appended claims. Accordingly, any one or more features of a given embodiment are not mandatory except where the claims expressly state otherwise.

Claims

1. A battery pack case structure characterized by comprising: The box structure comprises a bottom plate, two oppositely arranged cross beams and two oppositely arranged longitudinal beams, the bottom plate, the two cross beams and the two longitudinal beams jointly form a containing space for containing an electric core stack, the longitudinal beam close to one side of the containing space is sequentially provided with a buffer layer and a reinforcing plate, the reinforcing plate, the buffer layer and the longitudinal beam jointly constitute an energy absorption layer, the energy absorption layer is configured to deform to absorb collision energy when subjected to a collision.

2. The box structure according to claim 1, characterized in that: The reinforcing plate is rigidly connected with the longitudinal beam, the reinforcing plate comprises a connecting portion, the connecting portion is rigidly connected with the longitudinal beam, the connecting portion comprises a weak sub-portion, the weak sub-portion is configured to break when the energy absorption layer is subjected to a collision greater than or equal to a preset collision intensity.

3. The box structure of claim 2, wherein, The reinforcing plate comprises a main body portion arranged along a first direction and the connecting portion arranged along a second direction, the first direction is a height direction of the box structure, the second direction is an extension direction of the cross beam, the connecting portion comprises a first sub-portion, the weak sub-portion and a second sub-portion connected in sequence, the size of the orthographic projection of the first sub-portion in the first direction and the size of the orthographic projection of the second sub-portion in the first direction are both greater than the size of the orthographic projection of the weak sub-portion in the first direction.

4. The box structure of claim 1, wherein, The reinforcing plate comprises a connecting portion, the connecting portion and the longitudinal beam are both connected with the buffer layer, and the connecting portion does not contact the longitudinal beam.

5. The box structure according to any one of claims 1 to 4, characterized in that The reinforcing plate comprises a main body portion arranged along a first direction, the first direction is a height direction of the box structure, the main body portion comprises at least one supporting sub-portion for supporting a side surface of the electric core stack, the ratio of the sum of the sizes of the orthographic projections of all the supporting sub-portions in the first direction to the size of the orthographic projection of the longitudinal beam in the first direction is greater than or equal to 1:

2.

6. The box structure of claim 5, wherein, The main body portion further comprises a protruding sub-portion, the protruding sub-portion protrudes towards a side close to the buffer layer, the ratio of the size of the orthographic projection of the protruding sub-portion in a second direction to the size of the orthographic projection of the buffer layer in the second direction is greater than 0.5:10 and less than or equal to 3:10, the second direction is an extension direction of the cross beam.

7. The box structure of claim 6, wherein, The main body portion comprises two supporting sub-portions, and the protruding sub-portion is located between the two supporting sub-portions.

8. The box structure of claim 5, wherein, The main body portion further comprises an inclined sub-portion, the inclined sub-portion comprises a free end and a fixed end, the free end is arranged in a spaced manner with the longitudinal beam, and the fixed end is connected with the supporting sub-portion, the distance between the free end and the longitudinal beam is less than the distance between the fixed end and the longitudinal beam.

9. The box structure of claim 5, wherein, The thickness of the main body portion in the second direction is 0.8-15 mm, the second direction is an extension direction of the cross beam.

10. The box structure of claim 5, wherein, The longitudinal beam comprises a longitudinal beam main body and a protruding portion, the protruding portion is located on a side of the longitudinal beam main body away from the containing space, the longitudinal beam main body comprises a supporting portion and a recessed portion, the distance between the supporting portion and the main body portion is less than the distance between the recessed portion and the main body portion.

11. The box structure of claim 1, wherein, The ratio of the size of the normal projection of the buffer layer in the first direction to the size of the normal projection of the longitudinal beam in the first direction is greater than or equal to 1:2, the thickness of the buffer layer in the second direction is 5-30 mm, the first direction is the height direction of the box structure, and the second direction is the extension direction of the cross beam.

12. The box structure of claim 1, wherein, The buffer layer is a foamed glue layer, a foam layer and / or a foamed aluminum layer.

13. A battery pack, characterized by The box structure comprises a box body and a plurality of longitudinal beams and cross beams arranged in the box body, wherein the box body comprises a first buffer layer arranged on the inner wall of the box body, and the first buffer layer is arranged on the inner wall of the box body in the form of a plurality of first buffer layer pieces arranged in the box body.

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