Battery cell module and battery pack

Abstract

This invention relates to the field of battery technology and discloses a cell module and battery pack, comprising: multiple pouch cells arranged along the X direction of the cell module, with an end plate located on the outer side of the multiple pouch cells along the X direction; the end plate includes a plate body and several perforated holes on the plate body, the plate body having an inner side surface near the pouch cells and an outer side surface opposite to the inner side surface, the outer side surface being a convex surface that gradually bulges outward from both ends in the Y direction towards the center of the plate body, the convex surface including a central top surface and inclined surfaces that transition to both sides of the central top surface, the inclined surfaces on both sides of the central top surface being connected to the two ends of the inner side surface along the Y direction via side connections. This invention, by increasing the thickness of the middle part of the end plate and reducing the thickness of both ends, makes the stress of the end plate along the Y direction more uniform, which can effectively improve the structural strength of the end plate to stably constrain the expansion of the pouch cells; moreover, the perforated holes help reduce the overall material usage of the end plate to reduce the weight of the end plate and improve the energy density of the battery module.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a cell module and a battery pack. Background Technology

[0002] As an important type of lithium-ion battery, pouch cells have the following key advantages: pouch cells are packaged with aluminum-plastic film, which makes them lighter than steel or aluminum-cased batteries, while also having higher volumetric and gravimetric energy densities, which helps improve the driving range of electric vehicles and the efficiency of portable devices; in the event of safety issues such as thermal runaway, pouch cells usually bulge rather than explode, effectively reducing the risk of accidents and giving users more reaction time.

[0003] In the battery cell module, the module end plate can provide stable structural support for the battery cell module, effectively resist the superimposed expansion force generated by the soft-pack battery cell during the charge and discharge cycle, and prevent the module from deforming; and when the vehicle encounters extreme working conditions such as vibration, impact or extrusion, the end plate can protect the soft-pack battery cell and connector inside the module.

[0004] In related technologies, the end plate structure has low rigidity. During battery pack compression tests, the module end plate is prone to breakage, which can puncture the pouch cells and lead to internal or external short circuits, insulation failure, or leakage from the pouch cells, affecting the safety of the battery pack. Moreover, during daily use, the expansion force of the pouch cells can cause the end plate to break and fail, affecting the cycle life of the battery pack. Summary of the Invention

[0005] In view of this, the present invention provides a cell module and a battery pack to solve the problems of battery pack compression, expansion force, and end plate breakage caused by low end plate stiffness, resulting in short circuits or leakage of soft-pack cells.

[0006] In a first aspect, the present invention provides a battery cell module, comprising: Multiple pouch cells are arranged along the X direction of the cell module; An end plate is located on the outer side of a plurality of pouch cells along the X direction. The end plate includes a plate body and a plurality of perforated holes on the plate body. The plurality of perforated holes are arranged along the X and Y directions. The plate body has an inner side surface near the pouch cell and an outer side surface opposite to the inner side surface. The outer side surface is a convex surface that gradually bulges outward from both ends in the Y direction toward the middle of the plate body. The convex surface includes a central top surface and inclined surfaces that transition to both sides of the central top surface. The inclined surfaces on both sides of the central top surface are connected to the two ends of the inner side surface along the Y direction through side connections.

[0007] Beneficial Effects: By arranging several perforations along the X and Y directions of the plate, the overall material usage of the end plate can be effectively reduced, thus lowering its weight. The outer surface of the plate gradually bulges outward from the two sides along the Y direction towards the center, causing the plate thickness to gradually increase from the two sides along the Y direction towards the center. This results in a cross-section that is thinner at both ends and thicker in the middle, with a smooth transition in thickness from both ends to the middle. The bending moment is large in the middle region of the plate, so increasing the thickness in the middle region increases the moment of inertia of the cross-section. The bending moment is small at both ends, so thinning the thickness at both ends saves material. This makes the maximum stress along the Y direction of the end plate more uniform, thereby increasing the structural strength of the end plate with the same material usage. This, in turn, more stably constrains the expansion of the pouch cells, preventing the end plate from bulging outward and losing its positioning constraint on the pouch cells. Moreover, under the same stiffness requirements, reducing the thickness at both ends of the end plate reduces the overall material usage of the end plate, further reducing its weight and increasing the energy density of the battery module. When the battery pack is subjected to external pressure or impact, the thickened structure in the middle can directly withstand greater frontal compressive force; the smooth, gradually changing thickness of the end plates avoids stress concentration caused by abrupt changes in cross-section, effectively reducing the risk of cracks and fractures in the end plates under impact loads, and improving the impact resistance reliability of the structure. This effectively solves problems such as battery pack compression and expansion forces caused by insufficient end plate stiffness, as well as end plate fractures during daily use, leading to short circuits in the battery pack or leakage from pouch cells.

[0008] In some optional embodiments, along the Y direction, the length of the pouch cell is L1, satisfying 150mm≤L1≤200mm; along the Z direction, the width of the pouch cell is W1, satisfying 75mm≤W1≤100mm. Along the Y direction, the length of the end plate is L2, satisfying 1.2L1≤L2≤1.3L1; along the Z direction, the width of the end plate is W2, satisfying 1.05W1≤W2≤1.1W1; along the X direction, the thickness from the center top surface of the plate to the inner side surface is T1, satisfying 0.12L2≤T1≤0.18L2.

[0009] Beneficial effects: By rationally setting the length and width of the end plate, space can be reserved for the tabs of the pouch cell and the installation space for the side structural components. It also ensures that the adhesive layer and cushioning material cover the end face of the pouch cell, while preventing glue and foam from overflowing onto the outside of the end plate. By rationally setting the ratio of the end plate's thickness to its length, and combining this with a gradually increasing thickness design, the thickness of the highest stress zone in the middle falls within the range of 12%-18%. This allows the end plate to withstand the long-term cyclic expansion force of the pouch cell and resist concentrated loads from external compression, effectively reducing the risk of breakage due to excessively low end plate stiffness.

[0010] In some optional embodiments, at least two rows of the perforated holes are provided on the plate along the X direction and at least two rows along the Y direction, and the two sides of the plate along the central axis in the Y direction are symmetrical about the central axis; a first cavity segment, a second cavity segment, a third cavity segment and a fourth cavity segment are provided sequentially from the side to the central axis; The width W3 of the first cavity segment satisfies 0.1L2≤W3≤0.15L2; The width W4 of the second type cavity segment satisfies 0.1L2≤W4≤0.15L2; The width W5 of the third type cavity segment satisfies 0.1L2≤W5≤0.15L2; The width W6 of the fourth type cavity segment satisfies 0.1L2≤W6≤0.15L2.

[0011] Beneficial effects: By setting at least two rows of perforated holes along both the X and Y directions on the plate, the weakening effect of the openings is dispersed across the two-dimensional plane, thus preventing the formation of continuous weak zones on the end plate. The force transmission path can be staggered through the reinforcing ribs between the holes, effectively improving the overall bending and shear strength of the end plate. By setting four cavity segments and rationally setting the width of each cavity segment, when the end plate is subjected to uniform internal expansion force or concentrated external extrusion force, the load is distributed to the walls of multiple perforated holes through the reinforcing ribs between adjacent cavity segments, significantly diluting the local load of a single cavity segment. Moreover, when the end plate is subjected to extreme loads such as impact or extrusion, after a single cavity segment undergoes plastic deformation, the remaining cavity segments can still continue to bear the force, preventing the instantaneous fracture of the entire end plate structure. This improves the impact toughness and failure safety of the end plate, thereby helping to reduce the risk of battery pack short circuits and leakage of soft-pack cells caused by end plate fracture.

[0012] In some alternative embodiments, the end plate has a first transverse reinforcing rib along the Z direction, and the width of the first transverse reinforcing rib is W7, satisfying 0.15W2≤W7≤0.25W2.

[0013] Beneficial effects: By reasonably setting the width of the first transverse stiffener, the concentrated load at the edge is evenly distributed to the overall structure of the end plate, reducing the local stress peak; under the long-term cyclic alternating expansion force of the soft-pack battery cell, the generation of fatigue cracks can be effectively reduced, thus extending the service life of the end plate.

[0014] In some alternative embodiments, along the X direction, on the side of the plate away from the center of the plate, the thickness of the plate is T2, satisfying 0.5T1≤T2≤0.8T1.

[0015] Beneficial effects: By reasonably setting the thickness of the plate on the side away from the middle of the plate, the material usage of the end plate can be effectively reduced while ensuring the load-bearing capacity of the end plate; moreover, the smooth thickness transition from the end plate to the middle makes the overall stress distribution of the end plate more uniform, which not only avoids stress concentration fracture in the middle, but also reduces the risk of failure due to excessive thinness at the end.

[0016] In some optional embodiments, along the X direction, the fourth cavity segment is provided with a first hollow segment, a second hollow segment, and a third hollow segment arranged sequentially. The first hollow segment includes a first hollow hole and an inner wall near the inner side surface. The height of the first hollow segment is H1, satisfying 0.2T1≤H1≤0.3T1. The second hollow segment has a second hollow hole and a second transverse reinforcing rib located between the first hollow hole and the second hollow hole. The height of the second hollow segment is H2, satisfying 0.2T1≤H2≤0.3T1. The third hollow segment includes a third hollow hole and a third transverse reinforcing rib located between the second hollow hole and the third hollow hole, as well as an outer wall near the outer side surface.

[0017] Beneficial effects: By reasonably setting the height of the first hollow section and / or the height of the second hollow section, the concentrated load at the end can be gradually diffused to the entire end plate section through the transverse stiffeners, effectively reducing the local stress peak on the end plate; under the long-term cyclic alternating expansion force and external impact load of the soft-pack battery cell, it can effectively suppress the occurrence of fatigue cracks on the end plate, improve the service life of the end plate and the structural fault tolerance under extreme working conditions.

[0018] In some optional embodiments, along the Y direction, a plurality of longitudinal reinforcing ribs are arranged at intervals within the plate body; a fixing hole is provided at the first cavity section, and an arc-shaped reinforcing rib is provided on the outer periphery of the fixing hole, the arc-shaped reinforcing rib being connected to the second transverse reinforcing rib and the longitudinal reinforcing rib respectively; in the first cavity section, the perforated holes are arranged irregularly; the radius r1 of the fixing hole satisfies 4mm≤r1≤10mm.

[0019] Beneficial effects: By placing the fixing holes on the second transverse and longitudinal reinforcing ribs that separate the perforated holes, and connecting the arc-shaped reinforcing ribs forming the fixing holes to the second transverse and longitudinal reinforcing ribs; the reinforcing ribs themselves have thick cross-sections and high strength, and the bolt preload can be evenly distributed to the entire end plate frame through the reinforcing ribs, avoiding problems such as hole edge tearing and stress concentration that are prone to occur when opening holes in thin-walled areas, thus achieving reliable fastening and load-bearing. Further rationally setting the radius of the fixing holes and selecting suitable bolt materials helps reduce the cost of bolt materials and makes the bolt tightening torque relatively reasonable, thereby reducing the requirements for assembly equipment and processes.

[0020] In some optional embodiments, the plate body is further provided with a weight reduction hole, which is located in the middle of the plate body, and the radius r2 of the weight reduction hole satisfies 8mm≤r2≤10mm.

[0021] Beneficial effects: By reasonably setting the radius of the weight reduction hole, the weight reduction area of ​​the end plate can be effectively controlled, ensuring that the stiffness loss of the end plate section is within an acceptable range; and under the cyclic alternating expansion force of the soft-pack battery cell or external impact load, the risk of stress concentration points at the edge of the weight reduction hole can be reduced, ensuring the fatigue life and structural integrity of the core load-bearing area.

[0022] In some optional embodiments, the side surface and the inclined surface have an included angle α, satisfying 90°≤α≤100°; the connection between the side surface and the inclined surface has a chamfer r3, the radius of the chamfer r3 satisfies r3≥2mm; each of the hollow holes has an arc-shaped chamfer inside.

[0023] Beneficial effects: By rationally setting the included angle between the side and the inclined surface, the preload or compressive force at the end can be evenly transferred to the thick section in the middle of the end plate at a reasonable angle, without stress abrupt changes, resulting in high load transfer efficiency and reducing the risk of local stress overload. Moreover, at the corner where the side and the inclined surface connect, there is no sharp angle stress concentration, and the effective cross-sectional thickness of the corner is guaranteed, which can withstand the local impact loads from assembly and collisions, reducing the risk of corner crushing or cracking. Furthermore, by setting chamfers at the connection between the side and the inclined surface and rationally setting the radius of the chamfers, the rounded chamfers can smoothly transfer stress through the arc surface. At the same time, the arc chamfers inside the hollow holes effectively reduce the peak stress at the corners, significantly improve the fatigue life of the end plate, and adapt to the alternating expansion loads throughout the entire life cycle of the soft-pack battery cell.

[0024] Secondly, the present invention also provides a battery pack, comprising: at least one cell module as described above.

[0025] Beneficial effects: Since the battery pack includes the aforementioned cell modules, it has the same effects as the cell modules, which will not be elaborated here. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a soft-pack battery cell in a battery cell module according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a mid-end board of a battery cell module according to an embodiment of the present invention; Figure 4 for Figure 3 Cross-sectional view along the middle AA; Figure 5 This is a side view of a mid-end plate of a battery cell module according to an embodiment of the present invention; Figure 6 This is a schematic diagram showing the markings on the end plate of a battery cell module according to an embodiment of the present invention; Figure 7 for Figure 6 A magnified view of part B in the image; Figure 8 This is a schematic diagram illustrating the mid-end board of a battery cell module according to an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures: 10. End plate; 100. Plate body; 101. Inner wall; 102. Second transverse reinforcing rib; 103. Longitudinal reinforcing rib; 104. First transverse reinforcing rib; 105. Third transverse reinforcing rib; 110. Hole; 111. First hole; 112. Second hole; 113. Third hole; 120. Inner side; 130. Outer convex surface; 131. Center top surface; 132. Inclined surface; 140. Side; 150. First cavity segment; 151. Fixing hole; 152. Arc-shaped reinforcing rib; 160. Second cavity segment; 170. Third cavity segment; 180. Fourth cavity segment; 190. Weight reduction hole; 20. Soft-pack battery cell; 30. Box body; 40. Cover plate. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] According to an embodiment of the present invention, in one aspect, such as Figures 2 to 7As shown, a battery cell module is provided, including: a plurality of soft-pack battery cells 20 arranged along the X direction of the battery cell module; an end plate 10 located outside the plurality of soft-pack battery cells 20 along the X direction; the end plate 10 includes a plate body 100 and a plurality of hollow holes 110 located on the plate body 100, the plurality of hollow holes 110 being arranged along the X and Y directions, the plate body 100 having an inner side surface 120 near the side of the soft-pack battery cells 20 and an outer side surface opposite to the inner side surface 120, the outer side surface being an outwardly convex surface 130 that gradually convexes outward from both ends of the Y direction toward the middle of the plate body 100, the outwardly convex surface 130 including a central top surface 131 and inclined surfaces 132 that are transitionally connected to both sides of the central top surface 131, the inclined surfaces 132 on both sides of the central top surface 131 being connected to the two ends of the inner side surface 120 along the Y direction via side surfaces 140.

[0031] In this embodiment, the X direction is the length direction of the cell module, i.e., the arrangement direction of the pouch cells 20, and multiple pouch cells 20 are arranged sequentially along the X direction. The Y direction is the width direction of the cell module. The Z direction is the height direction of the cell module. An end plate 10 is arranged on the outermost side of the pouch cells 20 along the X direction of the cell module to constrain the pouch cells 20 from both ends and withstand the expansion force and external extrusion force of the pouch cells 20. The end plate 10 includes a plate body 100, on which a plurality of perforated holes 110 are provided, and the plurality of perforated holes 110 are arranged along the X and Y directions of the plate body; thereby effectively reducing the overall material usage of the end plate 10, so as to reduce the weight of the end plate 10.

[0032] Along the X direction, the flat surface of the end plate 10 near the soft-pack battery cell 20 is the inner side 120, and the side wall where the inner side 120 is located is the inner wall 101. The inner wall 101 is in contact with the large surface of the soft-pack battery cell 20 to transmit expansion force. The side of the end plate 10 facing away from the soft-pack battery cell 20 is the outer side, and the side wall where the outer edge is located is the outer wall. Among them, the outer side is a convex surface 130 that gradually bulges outward from both ends towards the middle of the plate body 100 in the Y direction. That is, in the direction extending from the two sides 140 of the plate body 100 towards the middle of the plate body 100, the thickness of the plate body 100 gradually increases, so that the plate body 100 forms a cross section that is thin at both ends and thick in the middle area. At the same time, the thickness of the plate body 100 smoothly transitions from both ends to the middle. Due to the gradual design of the plate 100, which is thicker in the middle and thinner at both ends, the outer side is inclined along the Y direction. That is, the inclined surfaces 132 on both sides of the middle part of the plate 100 together form the outer contour with a gradual thickness, realizing a smooth transition from the minimum thickness of the plate 100 to the maximum thickness in the middle.

[0033] For end plate 10, the bending moment is large in the middle region of plate 100, so increasing the thickness of the middle region increases the moment of inertia of the section. The bending moment is small in the two ends of plate 100, so thinning the thickness of the two ends saves material. This makes the maximum stress of end plate 10 in the Y direction more uniform, thereby increasing the structural strength of end plate 10 with the same amount of material. This more stably constrains the expansion of the pouch cell, preventing end plate 10 from bulging outward and losing its positioning constraint on pouch cell 20. Moreover, under the same stiffness requirements, by reducing the thickness of the two ends of end plate 10, the overall material usage of end plate 10 can be reduced, thereby further reducing the weight of end plate 10 and increasing the energy density of the battery module. Furthermore, when the battery pack is subjected to external compression or collision, the thickened structure in the middle can directly withstand greater frontal compression force; the smooth and gradual thickness of end plate 10 avoids stress concentration caused by abrupt changes in the cross section, effectively reducing the risk of cracking and fracture of end plate 10 under impact load, and improving the impact resistance reliability of the structure. This effectively solves the problems caused by the low stiffness of the end plate 10, which leads to battery pack compression, expansion force, and breakage of the end plate 10 during daily use, resulting in short circuits in the battery pack or leakage of the soft-pack cells 20.

[0034] like Figure 8 As shown, in one embodiment, along the Y direction, the length of the soft-pack battery cell 20 is L1, satisfying 150mm≤L1≤200mm; along the Z direction, the width of the soft-pack battery cell 20 is W1, satisfying 75mm≤W1≤100mm; along the Y direction, the length of the end plate 10 is L2, satisfying 1.2L1≤L2≤1.3L1; along the Z direction, the width of the end plate 10 is W2, satisfying 1.05W1≤W2≤1.1W1; along the X direction, the thickness from the center top surface 131 to the inner side surface 120 of the plate 100 is T1, satisfying 0.12L2≤T1≤0.18L2.

[0035] In this embodiment, along the Y direction, the length L1 of the pouch cell 20 is the long side dimension of the large surface of the pouch cell 20, and is in the same direction as the length direction of the end plate 10 itself. The positive and negative tabs of the pouch cell 20 are led out from the two sides along the length direction. Along the Z direction, the width of the pouch cell 20 is the short side dimension of the large surface of the pouch cell 20, and is in the same direction as the width direction of the end plate 10 itself. Along the Y direction, the length L2 of the end plate 10 is the length dimension of the end plate 10 itself. Along the Z direction, the width W2 of the end plate 10 is the width dimension of the end plate 10 itself. Along the X direction, the thickness T1 from the center top surface 131 to the inner side surface 120 of the plate 100 is the dimension of the end plate 10 along the stacking direction of the pouch cells 20, referring to the maximum thickness of the middle region of the end plate 10; moreover, the thickness of the end plate 10 determines the bending stiffness of the end plate 10 along the stacking direction of the pouch cells 20.

[0036] The length L1 of the pouch cell 20 can be any value or a value between any two of the following: 150mm, 155mm, 160mm, 165mm, 170mm, 175mm, 180mm, 185mm, 190mm, 195mm, and 200mm. The width W1 of the pouch cell 20 can be any value or a value between any two of the following: 75mm, 80mm, 85mm, 90mm, 95mm, and 100mm.

[0037] Furthermore, the length L2 of the end plate 10 can be any value from 1.2L1, 1.21L1, 1.22L1, 1.23L1, 1.24L1, 1.25L1, 1.26L1, 1.27L1, 1.28L1, 1.29L1, and 1.3L1, or a value between any two of these values. If the length of the end plate 10 is too small, such as less than 1.2L1, the space between the tab and the connection structure may be insufficient, increasing the assembly difficulty of the pouch cell 20 and making it prone to tab interference or insufficient connection strength. If the length of the end plate 10 is too large, such as greater than 1.3L1, it will waste the lateral space of the cell module and directly reduce the volumetric energy density of the cell module.

[0038] By appropriately setting the length of the end plate 10, space can be reserved for the tabs of the pouch cell 20 and the installation space for the side structural components. The positive and negative tabs of the pouch cell 20 extend from both sides in the Y direction and need to be bent before connecting to the busbar or adapter plate. The part of the end plate 10 that extends beyond the pouch cell 20 provides a safety space for the tab bending and electrical connection components, preventing the tabs from being squeezed by the end plate 10 and causing a short circuit. The two sides 140 of the end plate 10 along the Y direction are the connection positions of the cell module frame, used to connect with the side plate or strap. The end plate 10 needs to extend beyond the main body of the pouch cell 20 to arrange the connection structure, thus forming a complete constraint frame.

[0039] The width W2 of the end plate 10 can be any value from 1.05W1, 1.06W1, 1.07W1, 1.08W1, 1.09W1, and 1.1W1, or a value between any two of these. If the width of the end plate 10 is too small, such as less than 1.05W1, the allowance in the width direction of the end plate 10 will be insufficient, and the glue may overflow. If the width of the end plate 10 is too large, such as greater than 1.1W1, it will increase the volume of the end plate 10, encroach on the installation space of the soft-pack battery cell 20, and reduce the assembly efficiency of the battery cell module.

[0040] Since structural adhesive or buffer foam and insulating sheets are usually applied between the pouch cell 20 and the end plate 10, by reasonably setting the width of the end plate 10, such as leaving a width margin of 5%-10%, it can be ensured that the adhesive layer and buffer material cover the end face of the pouch cell 20, while preventing adhesive and foam from overflowing to the outside of the end plate 10. Moreover, small components such as sampling line fixing seats, temperature sensors, and insulation limiting bosses are usually arranged on the upper and lower edges of the end plate 10 in the width direction. Therefore, the end plate 10 needs to extend slightly beyond the arrangement space of the pouch cell 20 to facilitate the installation of edge components.

[0041] The thickness T1 of the end plate 10 can be any value among 0.12L2, 0.13L2, 0.14L2, 0.15L2, 0.16L2, 0.17L2, and 0.18L2, or a value between any two of these values. If the thickness of the end plate 10 is too small, such as less than 0.12L2, the overall stiffness of the end plate 10 will be too low, resulting in excessive deformation under long-term expansion loads, and even fatigue fracture, triggering safety risks such as leakage and short circuits in the pouch cell 20. If the thickness of the end plate 10 is too large, such as greater than 0.18L2, the weight and volume of the end plate 10 will increase, the material utilization rate will decrease, and thus the energy density of the cell module will be sacrificed.

[0042] By reasonably setting the ratio of the thickness to the length of the end plate 10, and combining it with the gradual thickness design of the end plate 10, the thickness of the middle highest stress zone falls within the range of 12%-18%, enabling the end plate 10 to withstand the long-term cyclic expansion force of the soft-pack battery cell 20, and also resist the concentrated load of external extrusion, thereby effectively reducing the risk of breakage caused by the end plate 10 having too low stiffness.

[0043] In one embodiment, a plurality of perforated holes 110 are provided in at least two rows along the X direction and at least two rows along the Y direction on the plate 100, and the two sides of the plate 100 along the central axis in the Y direction are symmetrical about each other about the central axis; a first cavity segment 150, a second cavity segment 160, a third cavity segment 170 and a fourth cavity segment 180 are provided sequentially from the side 140 to the central axis; the width W3 of the first cavity segment 150 satisfies 0.1L2≤W3≤0.15L2; the width W4 of the second cavity segment 160 satisfies 0.1L2≤W4≤0.15L2; the width W5 of the third cavity segment 170 satisfies 0.1L2≤W5≤0.15L2; and the width W6 of the fourth cavity segment 180 satisfies 0.1L2≤W6≤0.15L2.

[0044] In this embodiment, by providing at least two rows of perforated holes 110 along both the X and Y directions on the plate 100, the weakening effect of the openings is dispersed onto a two-dimensional plane, thus preventing the formation of continuous weak zones on the end plate 10. The force transmission path can be staggered in the reinforcing ribs between the holes, effectively improving the overall bending and shear strength of the end plate 10. Moreover, the stress concentration range around each perforated hole 110 is small and the peak value is low. Combined with the reinforcing ribs between the perforated holes 110, a grid-like load-bearing skeleton can be formed, allowing the load to be evenly distributed, significantly improving the fatigue resistance and impact toughness of the plate 100.

[0045] The central axis O along the Y direction of the plate 100 is located at the center of the plate 100, making the plate 100 symmetrical along the central axis O. On one side of the central axis O, in the direction extending from the side 140 of the plate 100 towards the central axis O, a first cavity segment 150, a second cavity segment 160, a third cavity segment 170, and a fourth cavity segment 180 are arranged sequentially on the plate 100. Based on the symmetrical design of the end plate 10, a set of four identical cavity segments are also symmetrically arranged on the other side of the central axis O, so that the end plate 10 as a whole forms a symmetrical layout with multiple hollow holes 110 at both ends, so as to reduce the overall weight of the end plate 10.

[0046] The width W3 of the first cavity segment 150 can be any value among 0.1L², 0.11L², 0.12L², 0.13L², 0.14L², and 0.15L², or a value between any two values. The width W4 of the second cavity segment 160 can be any value among 0.1L², 0.11L², 0.12L², 0.13L², 0.14L², and 0.15L², or a value between any two values. The width W5 of the third cavity segment 170 can be any value among 0.1L², 0.11L², 0.12L², 0.13L², 0.14L², and 0.15L², or a value between any two values. The width W6 of the fourth type cavity segment 180 can be any value among 0.1L2, 0.11L2, 0.12L2, 0.13L2, 0.14L2, and 0.15L2, or a value between any two of these values.

[0047] If the width of each cavity segment is too small, such as less than 0.1L², it indicates that the structural ribs between two adjacent cavity segments are too densely arranged. On the one hand, this will increase the overall material consumption of the end plate 10, and on the other hand, it will make the mold structure more complex. During injection molding or die casting of the end plate 10, the difficulty of melt filling will increase, and molding defects such as material shortage and shrinkage cavities will easily occur, increasing the manufacturing cost of the end plate 10. If the width of each cavity segment is too large, such as greater than 0.15L², the span of the cavity segment wall is too large. When subjected to the expansion pressure of the soft-pack battery cell 20 or external extrusion pressure, the cavity is prone to local indentation, causing the cavity to fail before the battery cell module as a whole, resulting in a decrease in the load-bearing capacity of the end plate 10.

[0048] By setting four cavity segments and reasonably setting the width of each cavity segment, when the end plate 10 is subjected to internal uniform expansion force or external concentrated extrusion force, the load is distributed to the walls of multiple hollow openings through the reinforcing ribs between adjacent cavity segments, thus significantly diluting the local load of a single cavity segment. Moreover, when the end plate 10 is subjected to extreme loads such as impact or extrusion, after a single cavity segment undergoes plastic deformation, the remaining cavity segments can still continue to bear the force, preventing the overall structure of the end plate 10 from breaking instantly. This improves the impact toughness and failure safety of the end plate 10, thereby helping to reduce the risk of battery pack short circuit and leakage of the soft-pack cell 20 caused by the breakage of the end plate 10.

[0049] In one embodiment, the end plate 10 has a first transverse reinforcing rib 104, and the width of the first transverse reinforcing rib 104 along the Z direction is W7, satisfying 0.15W2≤W7≤0.25W2.

[0050] In this embodiment, the first transverse reinforcing rib 104 extends along the Y direction, penetrating from one side of the end plate to the other in the Y direction; the first transverse reinforcing rib 104 intersects with the longitudinal reinforcing ribs 103 that separate the four cavity segments, together forming a closed multi-hole grid structure 110. Along the Z direction, the width W7 of the first transverse reinforcing rib 104 can be any value among 0.15W2, 0.16W2, 0.17W2, 0.18W2, 0.19W2, 0.20W2, 0.21W2, 0.22W2, 0.23W2, 0.24W2, and 0.25W2, or a value between any two values. If the width of the first transverse reinforcing rib 104 is too small, such as less than 0.15W2, the moment of inertia of the first transverse reinforcing rib 104 itself will be too small. Under the expansion force of the soft-pack battery cell 20 or the external extrusion force, the first transverse reinforcing rib 104 will bend and deform before the cavity wall, losing its supporting function for the end plate 10. If the width of the first transverse reinforcing rib 104 is too large, such as greater than 0.25W2, the first transverse reinforcing rib 104 will significantly encroach on the area of ​​the hollow cavity, thereby relatively increasing the overall material usage of the end plate 10, which will not only increase the material cost, but also reduce the volume or weight energy density of the battery cell module.

[0051] The first transverse stiffener 104 can serve as a force transmission skeleton. By reasonably setting the width of the first transverse stiffener 104, the concentrated load at the edge can be evenly distributed to the overall structure of the end plate 10, reducing the local stress peak. Under the long-term cyclic alternating expansion force of the soft-pack battery cell 20, the generation of fatigue cracks can be effectively reduced, thus extending the service life of the end plate 10.

[0052] In one embodiment, along the X direction, on the side of the plate 100 away from the middle of the plate 100, the thickness of the plate 100 is T2, which satisfies 0.5T1≤T2≤0.8T1.

[0053] In this embodiment, T2 is the thickness of the outermost edge of the plate 100 along the Y direction, i.e., the minimum value of the gradually changing thickness of the end plate 10. From the minimum thickness T2 at the end edge, it smoothly increases along the Y direction towards the central axis O, eventually reaching the maximum thickness T1 in the middle region. On the side of the plate 100 away from the middle of the plate 100, the thickness T2 of the plate 100 can be any value among 0.5T1, 0.55T1, 0.6T1, 0.65T1, 0.7T1, 0.75T1, and 0.8T1, or a value between any two of these values.

[0054] If T2 is too small, such as less than 0.5T1, the cross-sectional strength at the connection point of the end plate 10 will be insufficient. When the module side plate, straps, or fasteners are connected to the connection point of the end plate 10, failure modes such as strap tearing, riveting detachment, or end breakage are likely to occur, thus losing the ability to constrain the soft-pack cell 20. If T2 is too large, such as greater than 0.8T1, the overall thickness difference of the end plate 10 will be too small, approaching that of a conventional end plate 10 with equal thickness. This will result in a large amount of material redundancy in the low-stress area of ​​the end plate 10, which will increase the weight of the end plate 10, increase material costs, and also encroach on the space of the cell module and reduce the volumetric energy density.

[0055] By reasonably setting the thickness of the side of the plate 100 away from the middle of the plate 100, the material usage of the end plate 10 can be effectively reduced while ensuring the end bearing capacity. Moreover, the smooth thickness transition from the end to the middle of the end plate 10 makes the overall stress distribution of the end plate 10 more uniform, which not only avoids stress concentration fracture in the middle, but also reduces the risk of failure due to excessive thinness at the end.

[0056] In one embodiment, along the X direction, a first hollow section, a second hollow section, and a third hollow section are sequentially arranged at the fourth cavity segment 180. The first hollow section includes a first hollow hole 111 and an inner wall 101 near the inner side surface 120. The height of the first hollow section is H1, satisfying 0.2T1≤H1≤0.3T1. The second hollow section has a second hollow hole 112 and a second transverse reinforcing rib 102 located between the first hollow hole 111 and the second hollow hole 112. The height of the second hollow section is H2, satisfying 0.2T1≤H2≤0.3T1. The third hollow section includes a third hollow hole 113 and a third transverse reinforcing rib 105 located between the second hollow hole 112 and the third hollow hole 113, as well as an outer wall near the outer side surface.

[0057] In this embodiment, along the X direction, a first hollow section, a second hollow section, and a third hollow section are sequentially arranged at the fourth cavity segment 180. The first hollow section is located near the inner side surface 120, the third hollow section is located near the outer side surface, and the second hollow section is located between the first and third hollow sections. The first hollow section includes a first hollow hole 111 and an inner wall 101 near the inner side surface 120; the second hollow section includes a second hollow hole 112 and a second transverse reinforcing rib 102 separating the first hollow hole 111 and the second hollow hole 112; the third hollow section includes a third hollow hole 113 and a third transverse reinforcing rib 105 separating the second hollow hole 112 and the third hollow hole 113, as well as an outer wall near the outer side surface.

[0058] The height H1 of the first hollowed-out section can be any value from 0.2T1, 0.21T1, 0.22T1, 0.23T1, 0.24T1, 0.25T1, 0.26T1, 0.27T1, 0.28T1, 0.29T1, 0.3T1, or a value between any two values. The height H2 of the second hollowed-out section can be any value from 0.2T1, 0.21T1, 0.22T1, 0.23T1, 0.24T1, 0.25T1, 0.26T1, 0.27T1, 0.28T1, 0.29T1, 0.3T1, or a value between any two values.

[0059] If the height of the first or second hollow section is too small, such as less than 0.2T1, it indicates that the horizontal layered ribs are arranged too densely, which increases the material usage of the end plate 10 and leads to higher material costs. Moreover, in injection molding and die casting, the narrow cavity has high melt flow resistance, which easily leads to defects such as material shortage, shrinkage cavities, and uneven filling, resulting in a decrease in mass production yield. If the height of the first or second hollow section is too large, such as greater than 0.3T1, since the cavity wall has no supporting span in the thickness direction, when a single cavity is too high, the thin plate of the cavity wall is prone to local depressions, buckling deformation, etc. under the expansion force of the soft-pack battery cell 20 or external extrusion force, thus losing the load-bearing capacity of the end plate 10.

[0060] By reasonably setting the height of the first hollow section and / or the height of the second hollow section, the concentrated load at the end can be gradually diffused to the entire cross section of the end plate 10 through the horizontal layered ribs, effectively reducing the local stress peak on the end plate 10; under the long-term cyclic alternating expansion force and external impact load of the soft-pack battery cell 20, the occurrence of fatigue cracks on the end plate 10 can be effectively suppressed, improving the service life of the end plate 10 and the structural fault tolerance under extreme working conditions.

[0061] In one embodiment, along the Y direction, a plurality of longitudinal reinforcing ribs 103 are arranged at intervals within the plate 100; a fixing hole 151 is provided at the first cavity section 150, and an arc-shaped reinforcing rib 152 is provided on the outer periphery of the fixing hole 151, the arc-shaped reinforcing rib 152 being connected to the second transverse reinforcing rib 102 and the longitudinal reinforcing rib 103 respectively; in the first cavity section 150, the hollow holes 110 are irregularly arranged; the radius of the fixing hole 151 satisfies 4mm≤r1≤10mm.

[0062] In this embodiment, the longitudinal stiffener 103 is the main force-transmitting component of the end plate 10, bearing the main bending stress and shear load. It also serves as the mounting base for the fixing hole 151 and the side plate connection position. The fixing hole 151 is formed on the longitudinal stiffener 103 and the second transverse stiffener 102 of the first cavity section 150, and the fixing hole 151 penetrates the end plate 10 along the Z direction, serving as a mechanical fastening mounting position for the battery cell module. The fixing hole 151 is the through hole for the battery cell module tie rod bolt. The matching bolt and nut can tighten the end plates 10 at both ends, forming a continuous clamping constraint on the soft-pack battery cell 20, providing preload force for the soft-pack battery cell 20, and serving as the mechanical connection basis for the end plate 10 to achieve anti-expansion and anti-compression functions.

[0063] An arc-shaped reinforcing rib 152 is provided on the outer periphery of the fixing hole 151, forming the fixing hole 151. The arc-shaped reinforcing rib 152 is connected to the second transverse reinforcing rib 102 and the longitudinal reinforcing rib 103 respectively. In order to better set the fixing hole 151 on the plate 100, the shape of the hollow hole 110 around the fixing hole 151 is adaptively changed, so that the hollow hole 110 near the fixing hole 151 is recessed inward, thereby making the hollow hole 110 in the first cavity section 150 irregularly arranged, thus reserving enough space for the opening of the fixing hole 151.

[0064] The radius r1 of the fixing hole 151 can be any value among 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, and 10mm, or any value between two of these. If the radius of the fixing hole 151 is too small, such as less than 4mm, the tensile and shear strength of the bolt section will be insufficient. Under long-term alternating loads, the bolt is prone to fatigue fracture, preload decay, and loosening, which will eventually cause the end plate 10 to lose its clamping constraint on the soft-pack battery cell 20, triggering safety problems such as uncontrolled expansion, displacement, and leakage of the soft-pack battery cell 20. Moreover, the smaller the hole diameter, the smaller the contact area between the bolt end face and the end plate 10, and the higher the local compressive stress at the hole edge under preload. This can easily lead to crushing of the hole perimeter ribs and plastic deformation, resulting in clamping force failure.

[0065] If the radius of the fixing hole 151 is too large, such as greater than 10mm, it will excessively weaken the strength of the end structure. The width of the first cavity section 150 itself is only within the range of 0.1L2-0.15L2, and it is located in the thin end region. An excessively large opening will cut off the effective cross-section of the reinforcing ribs around the fixing hole 151, causing the stress concentration around the fixing hole 151 to increase. This will make the end plate 10 prone to tearing failure along the fixing hole 151, which will damage the reliability of the end plate 10 connection. Moreover, an excessively large fixing hole 151 means that larger bolt materials are required, resulting in higher costs and a significant increase in the required tightening torque. This will also increase the requirements for assembly equipment and processes, which is not conducive to reducing material costs during mass production.

[0066] By creating fixing holes 151 on the second transverse reinforcing rib 102 and longitudinal reinforcing rib 103 of the separating perforated holes 110, and connecting the arc-shaped reinforcing rib 152 forming the fixing holes 151 with the second transverse reinforcing rib 102 and longitudinal reinforcing rib 103, the reinforcing ribs themselves have thick cross-sections and high strength. The bolt preload can be evenly distributed to the entire end plate 10 frame through the reinforcing ribs, avoiding problems such as hole edge tearing and stress concentration that are prone to occur when opening holes in thin-walled areas. This achieves reliable fastening and load bearing. Further rationally setting the radius of the fixing holes 151 and selecting suitable bolt materials helps to reduce the cost of bolt materials and make the bolt tightening torque relatively reasonable, thereby reducing the requirements for assembly equipment and processes.

[0067] In some feasible implementations, along the Y direction, the width of each cavity segment is formed by the combination of the length of the perforated hole 110 and the longitudinal reinforcing rib 103. Specifically, the perforated hole 110 eliminates redundant material in low-stress areas, directly reducing the weight and material cost of the end plate 10. Through the combination of the perforated hole 110 and the longitudinal reinforcing rib 103, each cavity segment simultaneously achieves the goals of load-bearing and weight reduction, avoiding the problems of insufficient rigidity of a purely large perforated hole 110 and excessive weight of a purely solid structure. The thickness T3 of the longitudinal reinforcing rib 103 satisfies 2mm ≤ T3 ≤ 4mm. Specifically, the thickness T3 of the longitudinal reinforcing rib 103 can be any value from 2mm, 2.5mm, 3mm, 3.5mm, and 4mm, or a value between any two of these. By rationally setting the thickness of the longitudinal reinforcing rib 103, the overall structural strength of the end plate 10 can be effectively increased, enhancing its load-bearing capacity, and preventing an increase in the overall weight of the end plate 10 due to excessively thick longitudinal reinforcing ribs 103.

[0068] In one embodiment, the plate 100 is also provided with a weight reduction hole 190, which is located in the middle of the plate 100. The radius r2 of the weight reduction hole 190 satisfies 8mm≤r2≤10mm.

[0069] In this embodiment, the two sides of the central axis O of the plate 100 correspond to the left and right cavity sections in the Y direction of the end plate, respectively. The solid central section in the middle of the plate 100 is the load-bearing section where the end plate 10 has the greatest thickness and the peak bending moment. The weight-reducing hole 190 is usually a circular hole opened in the middle of the plate 100 and on the outer side of the end plate 10 away from the soft-pack battery cell 20. The circular hole structure has good load-bearing capacity and helps to reduce the weight of the end plate 10. Similarly, a second arc-shaped reinforcing rib is provided on the outer periphery of the weight-reducing hole 190. The second arc-shaped reinforcing rib is connected to the third transverse reinforcing rib 105 and the longitudinal reinforcing rib 103. The shape of the second hollow hole 112 is adapted to fit the weight-reducing hole 190, so that the second hollow hole 112 is recessed inward near the weight-reducing hole 190, thereby reserving enough space for the opening of the weight-reducing hole 190.

[0070] The radius r2 of the circular hole can be any value from 8mm, 8.5mm, 9mm, 9.5mm, and 10mm, or any value between two of these. If the radius of the circular hole is too small, such as less than 8mm, under the alternating expansion force or external extrusion force of the pouch cell 20, a severe stress concentration effect will occur at the edge of the circular hole, making fatigue cracks more likely to appear in the high-stress central region, thus making the edge of the circular hole a weak point in the end plate 10 structure. If the radius of the circular hole is too large, such as greater than 10mm, the circular hole will excessively reduce the effective load-bearing cross section in the central region, resulting in a significant decrease in the moment of inertia of the cross section, directly weakening the bending stiffness of the end plate 10, offsetting the strength gain of the gradually thickened design, and even causing fracture in the central region.

[0071] By reasonably setting the radius of the weight reduction hole 190, the weight reduction area of ​​the end plate 10 can be effectively controlled, ensuring that the stiffness loss of the end plate 10 section is within an acceptable range; and under the cyclic alternating expansion force or external impact load of the soft-pack battery cell 20, the risk of stress concentration points at the edge of the weight reduction hole 190 can be reduced, thus ensuring the fatigue life and structural integrity of the core load-bearing area.

[0072] In one embodiment, there is an included angle α between the side surface 140 and the inclined surface 132, which satisfies 90°≤α≤100°; the connection between the side surface 140 and the inclined surface 132 is chamfered, and the radius of the chamfer r3 satisfies r3≥2mm; each hollow hole 110 is provided with an arc-shaped chamfer inside.

[0073] In this embodiment, the included angle α between the side surface 140 and the inclined surface 132 can be any value among 90°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99°, and 100°, or a value between any two of these values. By reasonably setting the included angle between the side surface 140 and the inclined surface 132, the inclined wall where the inclined surface 132 is located can uniformly transfer the preload or extrusion force at the end to the thick section in the middle of the end plate 10 at a reasonable angle, without stress abrupt changes, resulting in high load transfer efficiency and reducing the risk of local stress overload. Moreover, at the corner where the side surface 140 and the inclined surface 132 connect, there is no sharp angle stress concentration, and the effective section thickness of the corner is guaranteed, which can withstand the local impact load caused by assembly and collision, reducing the risk of corner crushing or cracking.

[0074] Furthermore, the chamfer radius represents the radius of the rounded transition between the inner side 140 and the inclined surface 132 of the end plate 10, in order to eliminate stress concentration at the sharp corners of the inner side of the end plate 10 and reduce the risk of cracking of the end plate 10. The radius of the chamfer r3 can be any value or a value between any two of the following: 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, and 4mm; and the radius of the chamfer can also be any value greater than 4mm. By setting chamfers at the connection between the side 140 and the inclined surface 132 and reasonably setting the radius of the chamfer, the rounded chamfer can smoothly transition stress through the arc surface, which can effectively reduce the peak stress at the corner, significantly improve the fatigue life of the end plate 10, and adapt to the alternating expansion load of the soft-pack battery cell 20 throughout its entire life cycle.

[0075] Furthermore, the corners of each perforated hole are rounded chamfers. By setting rounded chamfers at the corners inside the perforated holes, stress can be smoothly transferred, effectively reducing the peak stress at the corners, significantly improving the fatigue life of the end plate, and adapting to the alternating expansion loads throughout the entire life cycle of the soft-pack battery cell.

[0076] As shown in Tables 1 and 2, experiments were conducted on the battery cell module provided in this invention, and the experimental results are as follows.

[0077] Table 1

[0078] Table 2

[0079] As shown in Tables 1 and 2, and in conjunction with Examples 1 to 6, the end plate 10 has sufficient strength to meet the usage requirements and works seamlessly with the soft-pack battery cell 20, thereby improving the volumetric energy density of the battery cell module; and the overall weight of the end plate 10 is reduced.

[0080] As shown in Comparative Examples 1 and 2, when L2 / L1 is 1 and W2 / W1 is 1, the allowance in the width direction of the end plate 10 is insufficient, resulting in glue overflow during assembly; due to assembly tolerances or cell expansion, the aluminum-plastic film sealing edge is squeezed; and the electrode tab connection strength is low. When L2 / L1 is 1.5 and W2 / W1 is 1.3, the volumetric energy density of the cell module decreases, the grouping efficiency decreases, and the risks of drop and random vibration conditions increase.

[0081] As shown in Comparative Examples 3 and 4, when T1 / L2 is 0.1 and W7 / W2 is 0.13, the stiffness of end plate 10 is too low. Under long-term expansion load, excessive deformation will occur, leading to a rapid decrease in the module assembly force and a reduction in the overall cycle life of the package; fatigue fracture will occur in end plate 10. When T1 / L2 is 0.2 and W7 / W2 is 0.28, end plate 10 meets the stiffness requirements, but the overall weight and volume of end plate 10 increase, the cost increases, and the energy density of the entire package decreases.

[0082] As shown in Comparative Examples 5 and 6, when H1 / T1 and H2 / T1 are both 0.15, the increased material usage of end plate 10 leads to an increase in the overall weight of end plate 10. Excessive stiffness and small deformation result in excessive expansion force in the module, causing a drop in cell capacity. When H1 / T1 and H2 / T1 are both 0.35, the hollow section is too high, causing localized depressions and buckling deformation. The bending stiffness of end plate 10 decreases, its load-bearing capacity is reduced, and localized cracking occurs.

[0083] According to an embodiment of the present invention, on the other hand, such as Figure 1 As shown, a battery pack is also provided, including at least one cell module, a housing 30, and a cover plate 40. Specifically, several cell modules are regularly arranged within the housing 30 to ensure efficient space utilization of the battery pack; multiple cell modules can be connected in series, parallel, or mixed via a busbar to form a battery pack. Each cell module has several pouch cells 20 arranged sequentially along the X-direction, and end plates 10 are provided at both ends of the cell module. Side plates are provided on both sides of the cell module to protect the pouch cells 20. The cover plate 40 is located above the cell module and is fixedly connected to the housing 30, thereby sealing the cell module within the housing 30.

[0084] According to an embodiment of the present invention, another aspect provides an electrical device including a battery pack. The technical solutions described in the embodiments of the present invention are applicable to various electrical devices using battery packs.

[0085] Electrical equipment can be vehicles, ships, spacecraft, etc. Vehicles can be gasoline-powered vehicles, natural gas-powered vehicles, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. This invention does not impose any special limitations on the aforementioned electrical equipment.

[0086] For ease of explanation, the following embodiments use a vehicle as an example of an electrical device according to an embodiment of the present invention.

[0087] The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery pack is installed inside the vehicle, and the battery pack can be located at the bottom, front, or rear of the vehicle. The battery pack can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The vehicle may also include a controller and a motor. The controller is used to control the battery pack to power the motor, for example, to meet the power needs of starting, navigation, and driving the vehicle. In other embodiments of the invention, the battery pack can not only serve as the vehicle's operating power source but also as the vehicle's drive power source, replacing or partially replacing gasoline or natural gas to provide driving force for the vehicle.

[0088] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell module, characterized in that, include: Multiple pouch cells are arranged along the X direction of the cell module; An end plate is located on the outer side of a plurality of pouch cells along the X direction. The end plate includes a plate body and a plurality of perforated holes on the plate body. The plurality of perforated holes are arranged along the X and Y directions. The plate body has an inner side surface near the pouch cell and an outer side surface opposite to the inner side surface. The outer side surface is a convex surface that gradually bulges outward from both ends in the Y direction toward the middle of the plate body. The convex surface includes a central top surface and inclined surfaces that transition to both sides of the central top surface. The inclined surfaces on both sides of the central top surface are connected to the two ends of the inner side surface along the Y direction through side connections.

2. The battery cell module according to claim 1, characterized in that, Along the Y direction, the length of the pouch cell is L1, which satisfies 150mm≤L1≤200mm; along the Z direction, the width of the pouch cell is W1, which satisfies 75mm≤W1≤100mm. Along the Y direction, the length of the end plate is L2, satisfying 1.2L1≤L2≤1.3L1; along the Z direction, the width of the end plate is W2, satisfying 1.05W1≤W2≤1.1W1; along the X direction, the thickness from the center top surface of the plate to the inner side surface is T1, satisfying 0.12L2≤T1≤0.18L2.

3. The cell module according to claim 2, characterized in that, The plate has at least two rows of perforations along the X direction and at least two rows along the Y direction. The two sides of the plate along the central axis in the Y direction are symmetrical about the central axis. A first cavity segment, a second cavity segment, a third cavity segment, and a fourth cavity segment are provided sequentially from the side to the central axis. The width W3 of the first cavity segment satisfies 0.1L2≤W3≤0.15L2; The width W4 of the second type cavity segment satisfies 0.1L2≤W4≤0.15L2; The width W5 of the third type cavity segment satisfies 0.1L2≤W5≤0.15L2; The width W6 of the fourth type cavity segment satisfies 0.1L2≤W6≤0.15L2.

4. The cell module according to claim 2, characterized in that, The end plate has a first transverse reinforcing rib along the Z direction, and the width of the first transverse reinforcing rib is W7, satisfying 0.15W2≤W7≤0.25W2.

5. The cell module according to claim 2, characterized in that, Along the X direction, on the side of the plate away from the middle of the plate, the thickness of the plate is T2, which satisfies 0.5T1≤T2≤0.8T1.

6. The cell module according to claim 3, characterized in that, Along the X direction, the fourth cavity segment is provided with a first hollow segment, a second hollow segment, and a third hollow segment arranged sequentially. The first hollow segment includes a first hollow hole and an inner wall near the inner side surface. The height of the first hollow segment is H1, satisfying 0.2T1≤H1≤0.3T1. The second hollow segment has a second hollow hole and a second transverse reinforcing rib located between the first hollow hole and the second hollow hole. The height of the second hollow segment is H2, satisfying 0.2T1≤H2≤0.3T1. The third hollow segment includes a third hollow hole, a third transverse reinforcing rib located between the second hollow hole and the third hollow hole, and an outer wall near the outer side surface.

7. The cell module according to claim 6, characterized in that, Along the Y direction, a plurality of longitudinal reinforcing ribs are arranged at intervals within the plate body; a fixing hole is provided at the first cavity section, and an arc-shaped reinforcing rib is provided on the outer periphery of the fixing hole, the arc-shaped reinforcing rib being connected to the second transverse reinforcing rib and the longitudinal reinforcing rib respectively; in the first cavity section, the hollow holes are arranged irregularly; the radius r1 of the fixing hole satisfies 4mm≤r1≤10mm.

8. The cell module according to any one of claims 1 to 7, characterized in that, The plate is also provided with a weight reduction hole, which is located in the middle of the plate. The radius r2 of the weight reduction hole satisfies 8mm≤r2≤10mm.

9. The cell module according to any one of claims 1 to 7, characterized in that, The side surface and the inclined surface have an included angle α, which satisfies 90°≤α≤100°; the connection between the side surface and the inclined surface has a chamfer r3, and the radius of the chamfer r3 satisfies r3≥2mm; each of the hollow holes has an arc-shaped chamfer inside.

10. A battery pack, characterized in that, include: At least one battery cell module as described in any one of claims 1 to 9.

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