End plate assembly for battery pack and battery pack

Abstract

The utility model provides an end plate assembly for a battery pack and the battery pack, the end plate assembly comprises a first plate and a second plate which are oppositely arranged, a plurality of first supporting structures are arranged between the first plate and the second plate at intervals, and each first supporting structure is connected with the first plate and the second plate to ensure the rigidity of the end plate assembly; it is ensured that the end plate assembly can provide enough supporting strength in the normal expansion process of the battery cell; meanwhile, the first supporting structure comprises a weak part, and the weak part is configured to be broken when the first plate and / or the second plate are / is collided with the collision strength larger than or equal to the preset collision strength, so that more deformation space is provided for deformation of the end plate, the end plate can effectively buffer the collision force, the battery cell is prevented from being directly impacted, and the service life of the battery cell is prolonged. And the collision safety of the battery pack is enhanced.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an end plate assembly for a battery pack and a battery pack. Background Art

[0002] With the continuous development of power battery technology, large-capacity and large-cell batteries are increasingly being used in battery modules. The mechanical structure of the battery module is a key factor affecting battery assembly and safety. The end plates used in battery assembly must not only withstand the expansion force of the battery cells during charge and discharge cycles, but also meet mechanical requirements such as vibration, impact, and extrusion to ensure battery safety.

[0003] The deformation energy absorption space of the existing end plate is relatively small, so when the battery pack is subjected to external collision, the end plate cannot provide sufficient deformation energy absorption space, resulting in the battery cell being directly hit by the external impact, causing a fire and explosion accident. Utility Model Content

[0004] In view of this, the purpose of the present application is to propose an end plate assembly for a battery pack and a battery pack to solve or partially solve the problems raised in the background technology.

[0005] Based on the above-mentioned purpose, the first aspect of the present application provides an end plate assembly for a battery pack, comprising a first plate and a second plate arranged opposite to each other, a plurality of first support structures being spaced apart between the first plate and the second plate, each of the first support structures being connected to the first plate and the second plate, the first support structure comprising a weak portion, and the weak portion being configured to break when the first plate and / or the second plate is subjected to a collision greater than or equal to a preset collision strength.

[0006] Optionally, the first supporting structure includes a first part, a weak part and a second part arranged in sequence along a first direction, and the orthographic projection of the weak part on the first plane is located between the orthographic projection of the first part on the first plane and the orthographic projection of the second part on the first plane, so that the weak part breaks when the first plate and / or the second plate is subjected to a collision greater than or equal to a preset collision intensity, the first plane is the plane where the first plate or the second plate is located, and the first direction is perpendicular to the first plane.

[0007] Optionally, a second supporting structure is further included, wherein the second supporting structure is connected to the first supporting structure, and the second supporting structure extends along a second direction, and the second direction is the height direction of the end plate assembly.

[0008] Optionally, the weak portion is located between the second supporting structure and the second portion.

[0009] Optionally, the multiple first support structures include a first substructure and multiple second substructures arranged in sequence from top to bottom, and the orthographic projection size of the weak part of the first substructure on the first plane is larger than the orthographic projection size of the weak part of the second substructure on the first plane.

[0010] Optionally, the length of the first substructure in the third direction is smaller than the length of the second substructure in the third direction, and the third direction is the length direction of the end plate assembly.

[0011] Optionally, the weak portion is a rectangular parallelepiped structure, an arc-shaped structure, an S-shaped structure or a Z-shaped structure.

[0012] Optionally, a ratio of a length of the weak portion in the first direction to a length of the first supporting structure in the first direction is 1:10 to 1:4.

[0013] Optionally, the length of the weak portion in the first direction is 1 to 5 mm.

[0014] Optionally, the cross-sectional area S of the weak portion on the second plane and the force strength f of the weak portion satisfy the condition: α≦f / S≦2α, where α is the material strength of the material used to make the weak portion, and the second plane is perpendicular to the first plane.

[0015] The second aspect of the present application provides a battery pack, characterized in that it includes a cell stack and two end plate assemblies as described in any one of the first aspects above, the two end plate assemblies are respectively located on opposite sides of the cell stack, and the first part of the end plate assembly is arranged close to the cell stack.

[0016] Optionally, the first portion is connected to the first plate, and the battery pack further includes a buffer layer, which is located between the battery cell stack and the first plate.

[0017] Optionally, a lower box body is further included, in which a storage space for accommodating the battery cell stack is provided. The lower box body includes a first crossbeam, a first longitudinal beam, a second crossbeam and a second longitudinal beam connected in sequence end to end. The first crossbeam and the second crossbeam extend along the first direction, and the end plate assembly is located between the battery cell stack and the first longitudinal beam or the second longitudinal beam.

[0018] From the above, it can be seen that the end plate assembly and battery pack for a battery pack provided in the present application, the end plate assembly includes a first plate and a second plate arranged opposite to each other, and a plurality of first support structures are arranged between the first plate and the second plate, and each first support structure is connected to the first plate and the second plate to ensure the rigidity of the end plate assembly, and ensure that the end plate assembly can provide sufficient support strength during the normal expansion of the battery cell; at the same time, the first support structure includes a weak portion, and the weak portion is configured to break when the first plate and / or the second plate is subjected to a collision greater than or equal to a preset collision strength, providing more deformation space for the deformation of the end plate, so that the end plate can effectively buffer the collision force, avoid direct impact on the battery cell, and enhance the collision safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 A first structural schematic diagram of an end plate assembly for a battery pack according to an embodiment of the present application is shown;

[0021] Figure 2 A side view of a first embodiment of an end plate assembly according to an embodiment of the present application is shown;

[0022] Figure 3 A cross-sectional schematic diagram of a first embodiment of an end plate assembly according to an embodiment of the present application is shown;

[0023] Figure 4 Shown Figure 3 A partial enlarged schematic diagram of B in the middle;

[0024] Figure 5 A cross-sectional schematic diagram of a second embodiment of an end plate assembly according to an embodiment of the present application is shown;

[0025] Figure 6 A schematic structural diagram of a second embodiment of an end plate assembly according to an embodiment of the present application is shown;

[0026] Figure 7 A schematic diagram of the structure of the end plate assembly and the battery cell stack when assembled in an embodiment of the present application is shown;

[0027] Figure 8 Shown Figure 7 A partial enlarged schematic diagram of center C;

[0028] Figure 9A schematic structural diagram of a third embodiment of an end plate assembly according to an embodiment of the present application is shown;

[0029] Figure 10 A schematic structural diagram of a battery pack equipped with an end plate assembly according to an embodiment of the present application is shown;

[0030] Figure 11 A schematic structural diagram of the lower box body of an embodiment of the present application is shown;

[0031] Figure 12 A cross-sectional schematic diagram of a first embodiment of a battery pack according to an embodiment of the present application is shown;

[0032] Figure 13 A cross-sectional schematic diagram of a second embodiment of the battery pack of the present application is shown.

[0033] In the figure: 1. End plate assembly; 11. First plate; 12. Second plate; 13. First supporting structure; 131. First part; 132. Weak part; 133. Second part; 13′, First substructure; 13″, Second substructure; 14. Second supporting structure; 15. Assembly slot; 16. Lifting slot; 17. Notch; 2. Battery cell stack; 21. Battery cell; 22. Bar; 3. Lower box; 31. First crossbeam; 32. First longitudinal beam; 33. Second crossbeam; 331. Flow channel of second crossbeam; 34. Second longitudinal beam; 35. Middle crossbeam; 351. Blocking plate; 352. Middle cavity; 353. Upper cavity; 354. Lower cavity; 4. Collection plate; 5. Cold plate; 51. Guide collector; 6. Pressure strip; 7. Protective layer; 8. Upper cover; 9. Buffer layer. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0035] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] In various cell integration designs, such as cell-to-pack (CTP), cell-to-body (CTB), and cell-to-chassis (CTC), cells are directly integrated into the casing. However, even when cells are directly integrated into the casing, a buffering, supporting, and thermally insulating structure is still required between the end cells and the casing. This structure is collectively referred to as an end plate.

[0037] At present, end plates generally adopt an integrated injection molding design. The end plates are composed of deformable fins and non-deformable transverse ribs. During the expansion process of the battery cell, the fins play an early supporting role. As the battery cell expands, the fins are squeezed and deformed by 1 to 2 mm. As the battery cell continues to expand and the pressure increases, the non-deformable transverse ribs play a supporting role.

[0038] Most existing end plates are injection-molded with high-strength plastic materials to ensure a certain degree of rigidity. Even if the fins have a deformable arc structure design, due to the characteristics of the material, their deformable space is small. When the expansion force increases in the later stage, there is still a risk of the end plate breaking, resulting in reduced support for the end plate and the risk of the battery cell diving due to uneven force.

[0039] In addition, the deformable fins and non-deformable transverse ribs of the end plate have only 1 to 2 mm of compression space, and the rear section is a hard contact interface. That is, when the battery pack is deformed by a violent collision from the end plate surface, the only 1 to 2 mm compression space of the end plate cannot provide sufficient deformation energy absorption space, resulting in the battery cell being directly impacted by the outside, causing a fire and explosion accident.

[0040] Therefore, how to provide a new end plate that can provide more deformation and energy absorption space when subjected to external collisions to reduce the risk of the battery cell being directly squeezed or collided by the outside is an issue that needs to be solved urgently.

[0041] Based on this, the present application provides an end plate assembly for a battery pack. Figure 1 A first structural schematic diagram of an end plate assembly 1 for a battery pack is shown.

[0042] See also Figure 1 As shown, the end plate assembly 1 includes a first plate 11 and a second plate 12 arranged opposite to each other, and a plurality of first support structures 13 are spaced apart between the first plate 11 and the second plate 12. Each first support structure 13 is connected to the first plate 11 and the second plate 12, and the first support structure 13 includes a weak portion 132, which is configured to break when the first plate 11 and / or the second plate 12 is subjected to a collision greater than or equal to a preset collision strength.

[0043] Specifically, the first plate 11 and the second plate 12 can be arranged in parallel, and the first plate 11 and the second plate 12 are connected by a plurality of first support structures 13 arranged at intervals. In this way, the first plate 11, the second plate 12 and the first support structure 13 constitute the basic frame structure of the end plate assembly 1 to ensure the rigidity of the end plate assembly 1, to ensure that the end plate assembly 1 can provide sufficient support strength during the normal expansion of the battery cell 21, and to ensure that the battery cell 21 is evenly stressed.

[0044] The first supporting structure 13 includes a weak portion 132 , which is configured to break when the first plate 11 and / or the second plate 12 is subjected to a collision greater than or equal to a preset collision strength. In this way, the weak portion 132 serves to cut off the transmission of the collision load.

[0045] Due to the fracture of the weak portion 132, part of the first supporting structure 13 is also fractured, so that the first plate 11 and the second plate 12 are no longer rigidly connected, and there is more deformation space between the two due to the fracture of the weak portion 132. In this way, when the first plate 11 or the second plate 12 of the end plate is subjected to excessive external collision force, the more deformation space generated by the fracture of the weak portion 132 can provide more space for the deformation of the end plate, thereby allowing the end plate to effectively buffer the collision force, avoid direct impact on the battery cell, and enhance the collision safety of the battery pack.

[0046] The preset collision strength is a collision strength preset based on actual experience. When the collision strength is greater than or equal to the preset collision strength, if the battery cell is directly impacted by the collision force, a fire and explosion accident may occur. Therefore, in the present application, when the first plate 11 and / or the second plate 12 is subjected to a collision greater than or equal to the preset collision strength, the weak portion 132 breaks, providing more deformation space for the deformation of the end plate, so that the end plate can effectively buffer the collision force, avoid direct impact on the battery cell, and enhance the collision safety of the battery pack.

[0047] Exemplarily, the preset collision strength is 100-200 kN.

[0048] Figure 2 A first side view of the end plate assembly 1 is shown, Figure 3 A first cross-sectional schematic diagram of the end plate assembly 1 is shown, Figure 4 Shown Figure 3 A partial enlarged schematic diagram of B in the figure.

[0049] In some embodiments, see Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown, the first supporting structure 13 includes a first portion 131, a weak portion 132 and a second portion 133 arranged in sequence along a first direction, and the orthographic projection of the weak portion 132 on the first plane is located between the orthographic projection of the first portion 131 on the first plane and the orthographic projection of the second portion 133 on the first plane, so that the weak portion 132 breaks when the first plate 11 and / or the second plate 12 is subjected to a collision greater than or equal to a preset collision strength. The first plane is the plane where the first plate 11 or the second plate 12 is located, and the first direction is perpendicular to the first plane.

[0050] Specifically, the first plane is the plane where the first plate 11 or the second plate 12 is located (ie Figure 1 The first direction is perpendicular to the first plane, and the first direction is Figure 1 and Figure 3 The direction shown by W in the middle.

[0051] The first supporting structure 13 includes a first portion 131, a weak portion 132 and a second portion 133 arranged in sequence along the first direction. The first portion 131 and the second portion 133 are respectively connected to the first plate 11 and the second plate 12. In this way, the first portion 131 and the weak portion 132 can cooperate with the first plate 11 and the second plate 12 connected thereto to jointly improve the rigidity of the end plate assembly 1, ensuring that the end plate assembly 1 can provide sufficient supporting strength during the normal expansion of the battery cell, ensuring that the battery cell is evenly stressed.

[0052] The orthographic projection of the weak portion 132 on the first plane is located between the orthographic projection of the first portion 131 on the first plane and the orthographic projection of the second portion 133 on the first plane, that is, the cross-sectional dimension of the weak portion 132 on the first plane is smaller than the cross-sectional dimensions of the first portion 131 and the weak portion 132 on the first plane. In this way, the dimension of the weak portion 132 is smaller than the dimensions of the first portion 131 and the weak portion 132, so that the stiffness of the weak portion 132 is smaller than the stiffness of the first portion 131 and the second portion 133.

[0053] In this way, when the first plate 11 and / or the second plate 12 is subjected to a collision greater than or equal to a preset collision strength, for example, the preset collision strength can be 100-200 kN, the first part 131 and the second part 133 will not break due to their greater rigidity, while the weak part 132 will break due to its smaller rigidity. The fracture of the weak part 132 provides more deformation space for the deformation of the end plate, so that the end plate can effectively buffer the collision force, avoid direct impact on the battery cell, and enhance the collision safety of the battery pack.

[0054] At the same time, since the first part 131 and the weak part 132 located at both ends of the first support structure 13 are larger in size and have greater rigidity, the first part 131 and the weak part 132 can better improve the rigidity of the end plate assembly 1, ensuring that the end plate assembly 1 can provide sufficient support strength during the normal expansion of the battery cell, ensuring that the battery cell is evenly stressed.

[0055] It is worth noting that this embodiment does not limit the relationship between the orthographic projection of the first part 131 on the first plane and the orthographic projection of the second part 133 on the first plane. For example, the orthographic projection of the first part 131 on the first plane can completely overlap with the orthographic projection of the second part 133 on the first plane, or it can be located within the orthographic projection of the second part 133 on the first plane, or it can cover the orthographic projection of the second part 133 on the first plane, that is, the size of the first part 131 can be exactly the same as the size of the second part 133, or it can be larger than the size of the second part 133, or it can be smaller than the size of the second part 133. The size relationship between the first part 131 and the second part 133 is set according to actual needs.

[0056] In some embodiments, see Figure 1 and Figure 3 The end plate assembly 1 further includes a second support structure 14, the second support structure 14 is connected to the first support structure 13, and the second support structure 14 extends along a second direction, which is the height direction of the end plate assembly 1 (i.e. Figure 1 direction shown by H in FIG).

[0057] Specifically, the second support structure 14 extends along the height direction of the end plate assembly 1 and is connected to the first support structure 13. In this way, the second support structure 14 can further enhance the rigidity of the end plate assembly 1 to ensure that the end plate assembly 1 can provide sufficient support strength during the normal expansion of the battery cell.

[0058] In some embodiments, see Figure 3 and Figure 4 , the weak portion 132 is located between the second supporting structure 14 and the second portion 133 .

[0059] Specifically, the weak portion 132 is located between the second support structure 14 and the second portion 133, that is, the second support structure 14 is directly connected to the first portion 131. In this way, when the end plate assembly 1 is subjected to a direction from the second portion 133 toward the first portion 131 (i.e. Figure 4When the battery 100 is colliding with the first part 131 (in the direction indicated by N in the figure), since the second support structure 14 is not connected to the weak part 132 and the rigidity of the weak part 132 is small, the weak part 132 is easy to break. At the same time, since the second support structure 14 is directly connected to the first part 131, the second support structure 14 can resist the external collision force together with the first part 131, thereby preventing the first part 131 and the second support structure 14 from breaking, thereby protecting the battery cell from being directly impacted by the external collision force and improving the collision safety of the battery cell.

[0060] In a specific implementation, when the end plate assembly 1 and the battery cell are assembled into a battery pack, the first portion 131 of the end plate assembly 1 is disposed close to the battery cell, and the second portion 133 is disposed away from the battery cell.

[0061] When the battery cell expands normally, the expansion force is from the first portion 131 toward the second portion 133 (i.e. Figure 4 In the direction shown by M in FIG, at this time, since the second supporting structure 14 is directly connected to the first part 131, and the first part 131 is directly connected to the first plate 11 or the second plate 12, the first plate 11 or the second plate 12, the first part 131 and the second supporting structure 14 together provide sufficient rigidity for the side of the end plate assembly 1 close to the battery cell, so that the end plate assembly 1 can provide sufficient support strength for the normal expansion of the battery cell.

[0062] When the battery pack is hit from outside, the end plate assembly 1 is hit from the second portion 133 toward the first portion 131 (i.e. Figure 4 Since the second support structure 14 is not connected to the weak portion 132 and the rigidity of the weak portion 132 is relatively small, the weak portion 132 is easily broken. At the same time, since the second support structure 14 is directly connected to the first portion 131, the second support structure 14 can resist the external collision force together with the first portion 131, thereby preventing the first portion 131 and the second support structure 14 from breaking, thereby protecting the battery cell from being directly impacted by the external collision force and improving the collision safety of the battery cell.

[0063] Figure 5 A second schematic cross-sectional view of the end plate assembly 1 is shown.

[0064] In some embodiments, see Figure 1 and Figure 5 The plurality of first support structures 13 include a first substructure 13 ' and a plurality of second substructures 13 ' ' arranged in sequence from top to bottom, and the weak portion 132 of the first substructure 13 ' is on the first plane (ie Figure 1 The orthographic projection size on the plane shown by P in FIG) is larger than the orthographic projection size of the weak portion 132 of the second substructure 13ˊˊ on the first plane.

[0065] Specifically, the weak portion 132 of the first substructure 13' is on the first plane (ie Figure 1 The orthographic projection size on the plane shown by P in the figure is larger than the orthographic projection size of the weak part 132 of the second substructure 13ˊˊ on the first plane, that is, the cross-sectional size of the weak part 132 at the top on the first plane is larger than the cross-sectional size of the weak parts 132 at the middle and lower parts. In this way, the rigidity of the weak part 132 at the top is greater, the rigidity of the top of the end plate assembly 1 is improved, and the fracture of the weak part 132 due to the impact on the top of the end plate assembly 1 is avoided, thereby improving the structural stability of the battery pack.

[0066] Figure 6 A second structural diagram of the end plate assembly 1 is shown. Figure 7 It shows a schematic structural diagram of the assembly of the end plate assembly 1 and the battery cell stack 2. Figure 8 Shown Figure 7 A partial enlarged schematic diagram of C in the middle.

[0067] In some embodiments, see Figure 6 As shown, the first substructure 13 ˊ is in the third direction (ie Figure 6 The length in the direction indicated by L in the figure is smaller than the length of the second substructure 13ˊˊ in the third direction, where the third direction is the length direction of the end plate assembly 1.

[0068] Specifically, the first substructure 13 ' is in the third direction (ie Figure 6 The length in the direction indicated by L in the figure is smaller than the length of the second substructure 13ˊˊ in the third direction, that is, the length of the first substructure 13ˊ is shorter than the length of the second substructure 13ˊˊ. Since the first substructure 13ˊ is located at the top of the end plate assembly 1, the shorter first substructure 13ˊ forms a gap 17 at the top of the end plate assembly 1. The gap 17 can provide installation space for the assembly of the end plate assembly 1 and the battery cell, thereby reducing the space required for the assembly of the two.

[0069] For example, see Figure 7 and Figure 8 As shown, the notch 17 can be used as a locking groove. When the end plate assembly 1 is assembled with the battery cell, the output electrode (not shown) connected to the tab 22 at the top of the battery cell can be inserted into the locking groove and locked with a fastener such as an insert nut or a stamped nut. In this way, the provision of the notch 17 facilitates the assembly of the battery cell and the end plate assembly 1 and can reduce the space required for the assembly of the two.

[0070] In some embodiments, the weak portion 132 is a rectangular parallelepiped structure, an arc-shaped structure, an S-shaped structure, or a Z-shaped structure.

[0071] Specifically, when the weak portion 132 is a rectangular parallelepiped structure, the weak portion 132 plays a supporting role when the battery cell expands normally, and when the battery cell is hit by an external force, the weak portion 132 breaks, which better prevents the transmission of the collision load.

[0072] When the weak portion 132 is an arc-shaped structure, an S-shaped structure or a Z-shaped structure, this type of structure has a variable space, which can provide more deformation space for the weak portion 132, and thus provide more deformation space for the end plate assembly 1, which can further reduce the risk of the battery cell being directly impacted.

[0073] In some embodiments, see Figure 3 and Figure 4 As shown, the length of the weak portion 132 in the first direction (ie Figure 4 L1 in FIG) and the length of the first support structure 13 in the first direction (ie Figure 3 The ratio (shown as L2 in FIG) is 1:10 to 1:4.

[0074] Specifically, when the ratio is 1:10 to 1:4, the length of the weak portion 132 in the first direction is moderate, which can ensure that the weak portion 132 can break to release deformation space when subjected to an external force of a certain magnitude, and can also ensure that the first support structure 13 has sufficient rigidity to support the normal expansion of the battery cell.

[0075] When the ratio is less than 1:10, the length of the weak portion 132 is too small, resulting in the second step not being effectively broken by the external impact force. When the ratio is greater than 1:4, the length of the weak portion 132 is too long, resulting in insufficient overall rigidity of the first support structure 13, and unable to support the normal expansion of the battery cell.

[0076] For example, the ratio of the length of the weak portion 132 in the first direction to the length of the first supporting structure 13 in the first direction may be 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, etc.

[0077] Furthermore, the length of the weak portion 132 in the first direction is 1 to 5 mm. For example, the length of the weak portion 132 in the first direction can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc.

[0078] In some embodiments, the end plate assembly 1 can be integrally formed from materials such as PA6+GF or PA66+30GF through an injection molding process, wherein PA6 is nylon 6 or polyamide 6, PA66 is nylon 66 or polyamide 66, GF is glass fiber, and 30GF is a main material with 30% glass fiber added.

[0079] In some embodiments, see Figure 1 and Figure 4As shown, the weak portion 132 is in the second plane (ie Figure 1 The cross-sectional area S on the plane shown by Q in the figure and the force strength f of the weak portion 132 satisfy the condition: α≦f / S≦2α, where α is the material strength of the material used to prepare the weak portion 132, and the second plane is perpendicular to the first plane.

[0080] Specifically, the cross-sectional area S of the weak portion 132 on the second plane can be calculated as L1*L2.

[0081] The material strength α of the material used to make the weak portion 132 is the strength of the material itself. For example, if the material used to make the end plate assembly 1 is PA6+30GF, then the material strength of PA6+30GF is 160 MPa.

[0082] Only by ensuring that α≦f / S≦2α can it be ensured that the weak portion 132 will not break when the battery cell expands normally, and it can be ensured that the end plate assembly 1 can provide sufficient supporting strength when the battery cell expands normally.

[0083] Furthermore, in actual application, the force strength f of the weak portion 132 needs to satisfy: 20kN≤f≤60kN, so S can be calculated based on F and α, and then the length L1 of the weak portion 132 can be calculated based on the length ratio of the first supporting structure 13 and the weak portion 132, and finally L2 can be calculated based on S and L1, so that the final size of the weak portion 132 can be obtained.

[0084] Furthermore, when the end plate assembly 1 includes n first support structures 13, each first support structure 13 is required to be designed with a weak portion 132. The load-bearing strengths of the first support structures 13 are f1, f2, ..., fn, respectively. The overall load-bearing capacity of the end plate assembly 1 is F = f1 + f2 + ..., fn. The typical requirement is 100kN ≤ F ≤ 200kN; if there are special requirements, the range can be appropriately expanded to 50kN ≤ F ≤ 400kN to ensure that the structural strength of the end plate assembly 1 meets actual requirements.

[0085] Figure 9 A third structural schematic diagram of the end plate assembly 1 is shown.

[0086] In some embodiments, see Figure 1 、 Figure 2 and Figure 9 As shown, the side of the end plate assembly 1 away from the battery cell can be provided with an assembly slot 15 and a lifting slot 16. The assembly slot 15 can be used to install the battery cell voltage sampling and temperature sampling management control unit (CMC) acquisition board 4, which facilitates the acquisition of various battery cell parameters during actual use of the battery cell. There is no need to set up a special space for installing the CMC acquisition board 4, saving assembly space.

[0087] The hoisting groove 16 facilitates hoisting of the end plate assembly 1 and is beneficial to practical use.

[0088] Figure 10 A schematic structural diagram of a battery pack equipped with an end plate assembly 1 is shown.

[0089] See also Figure 10 The present application also provides a battery pack, comprising a cell stack 2 and two end plate assemblies 1 according to any one of the first aspects above, the two end plate assemblies 1 being located on opposite sides of the cell stack 2, and the first part 131 of the end plate assembly 1 being arranged close to the cell stack 2.

[0090] Specifically, the two end plate assemblies 1 are located on opposite sides of the cell stack 2. Thus, the two end plate assemblies 1 can provide support and cushioning for the cell stack 2 from both sides. When the cell stack 2 is subjected to an external collision, the weak portion 132 of the end plate assembly 1 breaks, providing more space for the end plate to deform. This allows the end plate to effectively cushion the impact force, preventing direct impact on the cell 21 and enhancing the collision safety of the battery pack.

[0091] The first part 131 of the end plate assembly 1 is arranged close to the battery cell stack 2. In this way, the first part 131 and the second support structure 14 connected to the first part 131 can jointly provide support for the side of the end plate assembly 1 close to the battery cell stack 2 with the first plate 11 or the second plate 12, and provide sufficient rigidity, so that the end plate assembly 1 can provide sufficient support strength for the normal expansion of the battery cell 21.

[0092] In some embodiments, the first portion 131 is connected to the first plate 11 , and the battery pack further includes a buffer layer 9 , which is located between the battery cell stack 2 and the first plate 11 .

[0093] Specifically, the buffer layer 9 is located between the battery cell stack 2 and the first plate 11 to further buffer the external impact force and protect the battery cell stack 2 to prevent the battery cell stack 2 from being directly impacted by the external impact force.

[0094] Furthermore, the buffer layer 9 can be made of foam. The foam can be melamine foam, foamed silicon foam, foamed polypropylene foam, etc. The thickness of the buffer layer 9 can be 0.5 to 5 mm to meet the actual buffering and protection requirements.

[0095] Figure 11 A structural schematic diagram of the lower box body 3 is shown.

[0096] In some embodiments, see Figure 10 and Figure 11As shown, the battery pack also includes a lower box 3, which is provided with a storage space for accommodating the battery cell stack 2. The lower box 3 includes a first crossbeam 31, a first longitudinal beam 32, a second crossbeam 33 and a second longitudinal beam 34 connected in sequence end to end. The first crossbeam 31 and the second crossbeam 33 are arranged along the first direction (i.e. Figure 10 The end plate assembly 1 extends between the battery cell stack 2 and the first longitudinal beam 32 or the second longitudinal beam 34.

[0097] Specifically, the first crossbeam 31 and the second crossbeam 33 extend along a first direction. When the battery pack is installed on a vehicle, the first direction may be the lateral direction of the vehicle, also referred to as the Y direction of the vehicle.

[0098] The end plate assembly 1 is located between the battery cell stack 2 and the first longitudinal beam 32 or the second longitudinal beam 34, that is, the two end plate assemblies 1 are installed in the Y direction of the vehicle. In this way, the end plate assembly 1 can buffer the collision force from both sides of the vehicle body, avoiding safety hazards caused by the collision of the battery cell stack 2 on both sides of the vehicle body, and improving the safety of the vehicle during lateral collision.

[0099] Furthermore, both ends of the first and second longitudinal beams 32, 34 can protrude beyond the crossbeam. This allows the protruding portions to connect the front and rear chassis frames when the battery pack is installed on the vehicle. Furthermore, the upper surfaces of the first and second longitudinal beams 32, 34 serve as a sealing interface between the floor and the vehicle body, and these two interfaces can be coplanar or not.

[0100] In some embodiments, the battery pack further includes at least one middle crossbeam 35, the middle crossbeam 35 extending along the first direction (ie Figure 10 The provision of the intermediate cross member 35 further enhances the strength of the battery pack in the first direction. When the battery pack is installed on a vehicle, the provision of the intermediate cross member 35 further enhances the safety of the battery pack during a lateral collision of the vehicle.

[0101] Figure 12 A first cross-sectional schematic diagram of a battery pack is shown.

[0102] In some embodiments, see Figure 10 and Figure 12 As shown, the battery pack also includes a cold plate 5. The cold plate 5 is sealed to the first crossbeam 31, first longitudinal beam 32, second crossbeam 33, second longitudinal beam 34, and middle crossbeam 35. The cold plate 5 is provided with multiple inlet and outlet nozzles, each of which is sealed to the middle crossbeam 35 to form a flow channel.

[0103] There is at least one cavity inside the middle cross beam 35 , and one of the at least one cavities must be connected to the water nozzle of the cold plate 5 to serve as a flow channel.

[0104] For example, the interior of the middle crossbeam 35 has three cavities: an upper cavity 353, a middle cavity 352, and a lower cavity 354. The upper cavity 353 is welded to the first and second longitudinal beams 32 and 34, providing structural support and requiring no sealing. The middle cavity 352 is sealed to the cold plate 5 nozzle to form a flow channel and requires sealing. The lower cavity 354 is connected to the cold plate 5 and requires no sealing.

[0105] Figure 13 A second cross-sectional schematic diagram of a battery pack is shown.

[0106] In some embodiments, see Figure 13 As shown, the first and second crossbeams 31, 33 can also integrate water cooling. In one approach, the front and rear crossbeams can each have two or more cavities 353, with the inner cavity near the box serving as the water-cooling channel. For specific connection methods, refer to the middle crossbeam 35. In another approach, the external cold plate 5 can be fixed to the first and second crossbeams 31, 33, respectively, using adhesive or other means. The cavities in the first and second crossbeams 31, 33 serve only as spaces for the water-cooling joints.

[0107] The bottom cold plate 5 has multiple inlet and outlet water nozzles, which are connected to the flow channels of the first crossbeam 31, the second crossbeam 33, and the middle crossbeam 35. These flow channels can form parallel water cooling channels, series channels, or a combination of series and parallel. The number of nozzles is not limited, but there must be at least two main water inlets and outlets.

[0108] The battery pack provided herein utilizes a unique arrangement of the lower case 3 and cells 21 to significantly enhance safety in the event of a vehicle side impact. The crossbeam structure of the case is utilized to enhance both rigidity and space utilization. Furthermore, the crossbeam structure incorporates a water-cooling design that, when combined with the cold plate 5, increases the cooling area for the cells 21, thereby reducing overall cell 21 temperature variation, individual cell 21 temperature variation, and overall battery temperature rise.

[0109] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. Within the scope of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the above aspects of the present application, which are not provided in detail for the sake of simplicity.

[0110] The embodiments of the present application are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An end plate assembly for a battery pack, characterized in that: It includes a first plate and a second plate arranged opposite to each other, a plurality of first supporting structures are arranged at intervals between the first plate and the second plate, each of the first supporting structures is connected to the first plate and the second plate, and the first supporting structure includes a weak portion, which is configured to break when the first plate and / or the second plate is subjected to a collision greater than or equal to a preset collision strength.

2. The end plate assembly according to claim 1, wherein: The first supporting structure includes a first portion, a weak portion, and a second portion arranged in sequence along a first direction, wherein the orthographic projection of the weak portion on the first plane is located between the orthographic projection of the first portion on the first plane and the orthographic projection of the second portion on the first plane, so that the weak portion breaks when the first plate and / or the second plate is subjected to a collision greater than or equal to a preset collision strength, the first plane is the plane where the first plate or the second plate is located, and the first direction is perpendicular to the first plane.

3. The end plate assembly according to claim 2, wherein: It also includes a second supporting structure, which is connected to the first supporting structure and extends along a second direction, which is the height direction of the end plate assembly.

4. The end plate assembly according to claim 3, characterized in that The weakened portion is located between the second support structure and the second portion.

5. The end plate assembly according to claim 3, wherein: The multiple first support structures include a first substructure and multiple second substructures arranged in sequence from top to bottom, and the orthographic projection size of the weak part of the first substructure on the first plane is larger than the orthographic projection size of the weak part of the second substructure on the first plane.

6. The end plate assembly according to claim 5, wherein: The length of the first substructure in the third direction is smaller than the length of the second substructure in the third direction, and the third direction is the length direction of the end plate assembly.

7. The end plate assembly according to claim 2, wherein: The weak portion is a rectangular parallelepiped structure, an arc-shaped structure, an S-shaped structure or a Z-shaped structure.

8. The end plate assembly according to claim 2, wherein: The ratio of the length of the weak portion in the first direction to the length of the first supporting structure in the first direction is 1:10 to 1:

4.

9. The end plate assembly according to claim 2, wherein: The length of the weak portion in the first direction is 1 to 5 mm.

10. The end plate assembly according to claim 2, wherein: The cross-sectional area S of the weak portion on the second plane and the force strength f of the weak portion satisfy the condition: α≦f / S≦2α, where α is the material strength of the material used to make the weak portion, and the second plane is perpendicular to the first plane.

11. A battery pack, characterized in that: It comprises a cell stack and two end plate assemblies according to any one of claims 1 to 10, wherein the two end plate assemblies are respectively located on opposite sides of the cell stack, and the first part of the end plate assembly is arranged close to the cell stack.

12. The battery pack according to claim 11, wherein: The first portion is connected to the first plate. The battery pack further includes a buffer layer located between the battery cell stack and the first plate.

13. The battery pack according to claim 11, wherein: It also includes a lower box body, in which a storage space for accommodating the battery cell stack is provided. The lower box body includes a first crossbeam, a first longitudinal beam, a second crossbeam and a second longitudinal beam connected in sequence end to end. The first crossbeam and the second crossbeam extend along the first direction. The end plate assembly is located between the battery cell stack and the first longitudinal beam or the second longitudinal beam.

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