Battery pack and energy storage equipment

Abstract

The embodiment of the utility model relates to the technical field of energy storage, and discloses a battery pack and energy storage equipment, the battery pack comprises a first end cover, a second end cover, a first fixing strip, a second fixing strip and a plurality of stacked battery cells; the first end cover and the second end cover are respectively positioned at the two ends of the plurality of battery cells along the stacking direction of the battery cells, and are respectively propped against the two battery cells positioned on the outermost side; one end of the first fixing strip is screwed and fixed with the first end cover through a first screwing assembly, and the other end of the first fixing strip is screwed and fixed with the second end cover through a second screwing assembly; one end of the second fixing strip is screwed and fixed with the first end cover through a third screwing assembly, and the other end of the second fixing strip is screwed and fixed with the second end cover through a fourth screwing assembly; along a second direction, the first fixing strip and the second fixing strip are respectively positioned on two sides of the plurality of battery cells, and the second direction is perpendicular to the stacking direction of the battery cells. According to the embodiment of the utility model, the assembly difficulty of the battery pack can be reduced.

Description

Technical Field

[0001] The embodiments of the utility model relate to the field of energy storage technology, and in particular to a battery pack and energy storage equipment. Background Art

[0002] As people's requirements for the capacity of energy storage devices become increasingly higher, the number of cells in the battery packs that make up the energy storage devices is also increasing. The bundling and fixation of multiple cells has gradually become a research focus.

[0003] The currently commonly used bundling and fixing method is: along the stacking direction of the battery cells, two end covers are placed at both ends of the battery cells respectively, and then the end covers and the battery cells are pressed tightly to create a pre-tightening force between the battery cells and the end covers, and then steel belts are used to bundle and fix the two end covers and the multiple battery cells between the two end covers.

[0004] During the implementation of the embodiment of the present invention, the inventors found that when the end caps and the battery cells are compressed, special tooling equipment is required to compress them and then put on steel strips for bundling, which makes assembly difficult. Utility Model Content

[0005] The main technical problem solved by the embodiments of the present invention is to provide a battery pack and an energy storage device, which can reduce the difficulty of assembling the battery pack.

[0006] In order to solve the above technical problems, a technical solution adopted in an embodiment of the present invention is: providing a battery pack, comprising a first end cover, a second end cover, a first fixing bar, a second fixing bar and a plurality of battery cells, which are stacked in sequence; along a first direction, the first end cover and the second end cover are respectively located at both ends of the plurality of battery cells, and the first end cover and the second end cover respectively abut the two battery cells located on the outermost sides, and the first direction is parallel to the direction in which the plurality of battery cells are stacked; one end of the first fixing bar is screwed and fixed to the first end cover by a first screw assembly, and the other end is screwed and fixed to the second end cover by a second screw assembly; one end of the second fixing bar is screwed and fixed to the first end cover by a third screw assembly, and the other end is screwed and fixed to the second end cover by a fourth screw assembly; wherein, along a second direction, the first fixing bar and the second fixing bar are respectively located on both sides of the plurality of battery cells, and the second direction is perpendicular to the first direction.

[0007] In some embodiments, a first through hole is provided at one end of the first fixing bar, a first screw groove is provided at the first end cover, and the first screw connection component is passed through the first through hole and screwed and fixed to the first screw groove.

[0008] In some embodiments, the first screw connection assembly includes a first reinforcement member and a first screw connection member, the first reinforcement member includes a first plug-in portion and a first abutment portion, one end of the first plug-in portion is connected to the first abutment portion; the first end cover is provided with a first receiving groove, the first screw groove is connected to the first receiving groove, the first plug-in portion is passed through the first through hole and is at least partially inserted into the first receiving groove, the first abutment portion abuts against the surface of the first fixing bar away from the first receiving groove, and the first screw connection member is passed through the first reinforcement member along the second direction and is screwed and fixed to the first screw groove.

[0009] In some embodiments, the first end cover is provided with a first reinforcing rib, and the first receiving groove is provided at one end of the first reinforcing rib.

[0010] In some embodiments, a second through hole is provided at one end of the first fixing bar away from the first end cover, a second screw groove is provided at the second end cover, and the second screw assembly is passed through the second through hole and screwed to the second screw groove.

[0011] In some embodiments, the second screw connection assembly includes a second reinforcement member and a second screw connection member, the second reinforcement member includes a second plug-in portion and a second abutment portion, one end of the second plug-in portion is connected to the second abutment portion; the second end cover is provided with a second receiving groove, the second screw groove is connected to the second receiving groove, the second plug-in portion is passed through the second through hole and is at least partially inserted into the second receiving groove, the second abutment portion abuts against the surface of the second fixing bar away from the second receiving groove, and the second screw connection member is passed through the second reinforcement member along the second direction and is screwed and fixed to the second screw groove.

[0012] In some embodiments, the second end cover is provided with a second reinforcing rib, and the second receiving groove is provided at one end of the second reinforcing rib.

[0013] In some embodiments, the battery pack further includes a first insulating member, and along the second direction, the first insulating member is located between the first fixing bar and the plurality of battery cells.

[0014] In some embodiments, the battery pack further includes a second insulating member, and along the second direction, the second insulating member is located between the second fixing bar and the plurality of battery cells.

[0015] In order to solve the above technical problems, another technical solution adopted in the embodiment of the present utility model is: to provide an energy storage device, including the above-mentioned battery pack.

[0016] The beneficial effects of the embodiments of the present invention are as follows: different from the prior art, in the embodiments of the present invention, by stacking multiple battery cells, the first end cover and the second end cover are respectively arranged at the two ends of the multiple battery cells, and the first end cover and the second end cover are respectively abutted against the two battery cells located on the outermost side, one end of the first fixing bar and the first end cover are screwed and fixed by a first screw assembly, the other end of the first fixing bar and the second end cover are screwed and fixed by a second screw assembly, one end of the second fixing bar and the first end cover are screwed and fixed by a third screw assembly, and the other end of the second fixing bar and the second end cover are screwed and fixed by a fourth screw assembly, and along the second direction, the first fixing bar and the second fixing bar are respectively located on both sides of the multiple battery cells, thereby realizing bundling and fixation between the multiple battery cells. Compared with the method of using steel belts for fixing, in this application, there is no need to use tooling equipment to compress the multiple battery cells and then put on the steel belts, which reduces the difficulty of assembling the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0018] Figure 1 This is a schematic structural diagram of a battery pack provided in an embodiment of the present invention at a first viewing angle;

[0019] Figure 2 This is a schematic diagram of the exploded structure of the battery pack provided in an embodiment of the present utility model;

[0020] Figure 3 is a schematic structural diagram of a battery pack provided in an embodiment of the present utility model at a second viewing angle;

[0021] Figure 4 is a schematic structural diagram of a battery pack provided in an embodiment of the present utility model from a third perspective;

[0022] Figure 5 yes Figure 4 Schematic diagram of the cross-section structure along the AA section;

[0023] Figure 6 yes Figure 5 Magnified view of the area shown in part A;

[0024] Figure 7 yes Figure 5 Enlarged view of the area shown in part B;

[0025] Figure 8 yes Figure 5 Enlarged view of the area shown in center C;

[0026] Figure 9 yes Figure 5 Enlarged view of the area shown in D in the middle;

[0027] Figure 10 It is a schematic diagram of the partial structure of the battery pack provided in the embodiment of the present utility model. DETAILED DESCRIPTION

[0028] In order to facilitate the understanding of the present invention, the present invention will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "inside", "outside", "vertical", "horizontal", etc. used in this specification indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0029] Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art in the field of the present invention. The terms used in this specification are intended only to describe specific embodiments and are not intended to limit the present invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0030] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] See also Figure 1 and Figure 2The battery pack 100 includes a first end cap 12, a second end cap 13, a first fixing bar 14, a second fixing bar 15, a first screw assembly 16, a second screw assembly 17, a third screw assembly 18, a fourth screw assembly 19 and a plurality of battery cells 11. The plurality of battery cells 11 are stacked along a first direction X. Along the first direction X, the first end cap 12 and the second end cap 13 are respectively located on both sides of the plurality of battery cells 11, and the first end cap 12 and the second end cap 13 respectively abut against the two battery cells 11 located on the outermost sides. One end of the first fixing bar 14 is screwed and fixed to the first end cap 12 by the first screw assembly 16, and the other end of the first fixing bar 14 is screwed and fixed to the second end cap 13 by the second screw assembly 17. Please combine Figure 3 One end of the second fixing bar 15 is screwed and fixed to the first end cover 12 via a third screw assembly 18, and the other end of the second fixing bar 15 is screwed and fixed to the second end cover 13 via a fourth screw assembly 19. In particular, along the second direction Y, the first fixing bar 14 and the second fixing bar 15 are respectively located on both sides of the multiple battery cells 11, and the second direction Y is perpendicular to the first direction X. In other words, when viewed along the third direction Z, the first end cover 12, the first fixing bar 14, the second end cover 13, and the second fixing bar 15 collectively surround the multiple battery cells 11, and because the first end cover 12 and the second end cover 13 respectively abut the two outermost battery cells 11, the first end cover 12, the first fixing bar 14, the second end cover 13, and the second fixing bar 15 can collectively fix the multiple battery cells 11, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. In this embodiment, one end of the first fixing bar 14 is fixed to the first end cover 12 by the first screw assembly 16, the other end of the first fixing bar 14 is fixed to the second end cover 13 by the second screw assembly 17, one end of the second fixing bar 15 is fixed to the first end cover 12 by the third screw assembly 18, and the other end of the second fixing bar 15 is fixed to the second end cover 13 by the fourth screw assembly 19. Compared with the method of bundling and fixing multiple battery cells 11 with steel strips in the prior art, the present application does not need to use special tooling equipment to compress the multiple battery cells 11 and then put on steel strips during the process of assembling the battery pack 100, thereby reducing the difficulty of assembling the battery pack 100.

[0032] In some embodiments, see Figure 5 and Figure 6 A first through hole 141 is provided at one end of the first fixing bar 14, and a first screw groove 121 is provided at the first end cover 12. At least a portion of the first screw component 16 passes through the first through hole 141 and is screwed and fixed to the first screw groove 121, and at least a portion of the first screw component 16 abuts against the surface of the first fixing bar 14 facing away from the first screw groove 121, thereby achieving fixation between the first fixing bar 14 and the first end cover 12.

[0033] It is worth noting that as the battery pack 100 is used for an extended period of time, the battery cells 11 will gradually expand, especially in the first direction X. Due to the superposition of the expansion amounts of the multiple battery cells 11, the expansion amount of the battery pack 100 is the largest, which also leads to a gradual increase in the shear force along the first direction X formed between the first end cover 12 and the first fixing bar 14, between the second end cover 13 and the first fixing bar 14, between the first end cover 12 and the second fixing bar 15, and between the second end cover 13 and the second fixing bar 15. If only screws are used to fix the above-mentioned end covers and the fixing bars, the fixing bars and the end covers will easily cut off the screws under the action of the shear force, resulting in poor stability in the fixation of the multiple battery cells 11.

[0034] To solve the above problems, in some embodiments, refer to Figure 5 and Figure 6 The first screw assembly 16 includes a first reinforcement 161 and a first screw 162. The first reinforcement 161 includes a first plug-in portion 1611 and a first abutment portion 1612. One end of the first plug-in portion 1611 is connected to the first abutment portion 1612. The first end cover 12 is provided with a first receiving groove 122. Along the second direction Y, the first screw groove 121 is located on the side of the first receiving groove 122 away from the first fixing bar 14, and the first screw groove 121 is connected to the first receiving groove 122. When viewed along the second direction Y, the diameter of the first receiving groove 122 is larger than the nominal diameter of the first screw groove 121. The first plug-in portion 1611 passes through the first through hole 141 and is inserted into the first receiving groove 122. The first abutment portion 1612 abuts against the surface of the first fixing bar 14 away from the first receiving groove 122. The first reinforcement 161 is also provided with a first fixing hole 1613, which passes through the first plug-in portion 1611 and the second abutment portion 1712 along the second direction Y. The first screw member 162 passes through the first fixing hole 1613 and the first receiving groove 122 in sequence and is screwed and fixed to the first screw groove 121, thereby fixing the first fixing strip 14, the first reinforcement 161 and the first end cover 12 to each other. Among them, the diameter of the first plug-in portion 1611 is roughly equal to that of the first receiving groove 122, so that the first plug-in portion 1611 can be inserted into the first receiving groove 122, and the first receiving groove 122 can limit the movement of the first plug-in portion 1611 perpendicular to the second direction Y. When the battery cell 11 expands, the shear force along the first direction X formed between the first end cover 12 and the first fixing bar 14 can directly act on the first reinforcement 161, thereby reducing the shear force borne by the first screw connector 162, reducing the risk of the first screw connector 162 being cut off under the action of the shear force after the battery cell 11 expands, and improving the stability of the fixation between the first fixing bar 14 and the first end cover 12.

[0035] In some embodiments, see Figure 1The first end cap 12 is provided with a first reinforcing rib 123, which extends from one end of the first end cap 12 to the other end along the second direction Y. The first screw groove 121 and the first receiving groove 122 are both provided at one end of the first reinforcing rib 123. In this embodiment, the provision of the first reinforcing rib 123 can reduce the risk of deformation of the first end cap 12, increase the strength of the first end cap 12, and thus improve the pressure-bearing capacity of the first end cap 12.

[0036] In some embodiments, see Figure 1 The first reinforcing ribs 123 are provided in a plurality, and are spaced apart along the third direction Z. Furthermore, the first reinforcing ribs 123 extend from one end of the first end cap 12 to the other end along the second direction Y. In this embodiment, the provision of the plurality of first reinforcing ribs 123 further enhances the strength of the first end cap 12, thereby further enhancing the compressive strength of the first end cap 12.

[0037] In some embodiments, see Figure 7 A second through hole 142 is provided at the end of the first fixing strip 14 away from the first end cover 12, and a second screw groove 131 is provided at the second end cover 13. At least a portion of the second screw component 17 passes through the second through hole 142 and is screwed and fixed to the second screw groove 131, and at least a portion of the second screw component 17 abuts against the surface of the second fixing strip 15 away from the second screw groove 131, thereby achieving fixation between the second fixing strip 15 and the second end cover 13.

[0038] In some embodiments, see Figure 7The second screw assembly 17 includes a second reinforcement member 171 and a second screw member 172. The second reinforcement member 171 includes a second plug-in portion 1711 and a second abutment portion 1712. One end of the second plug-in portion 1711 is connected to the second abutment portion 1712. The second end cover 13 is provided with a second receiving groove 132. Along the second direction Y, the second screw groove 131 is located on the side of the second receiving groove 132 away from the first fixing bar 14, and the second screw groove 131 is connected to the second receiving groove 132. When viewed along the second direction Y, the diameter of the second receiving groove 132 is larger than the nominal diameter of the second screw groove 131. The second plug-in portion 1711 passes through the second through hole 142 and is inserted into the second receiving groove 132. The second abutment portion 1712 abuts against the surface of the first fixing bar 14 away from the second receiving groove 132. The second reinforcement 171 is also provided with a second fixing hole 1713, which passes through the second plug-in portion 1711 and the second abutment portion 1712 along the second direction Y. The second screw member 172 passes through the second fixing hole 1713 and the second receiving groove 132 in sequence and is screwed and fixed to the second screw groove 131, thereby fixing the first fixing strip 14, the second reinforcement 171 and the second end cover 13 to each other. Among them, the diameters of the second plug-in portion 1711 and the second receiving groove 132 are roughly equal, so that the second plug-in portion 1711 can be inserted into the second receiving groove 132, and the second receiving groove 132 can limit the movement of the second plug-in portion 1711 perpendicular to the second direction Y. When the battery cell 11 expands, the shear force along the first direction X formed between the second end cover 13 and the first fixing bar 14 can directly act on the second reinforcement 171, thereby reducing the shear force borne by the second screw connector 172, reducing the risk of the second screw connector 172 being cut off under the action of the shear force after the battery cell 11 expands, and improving the stability of the fixation between the first fixing bar 14 and the second end cover 13.

[0039] In some embodiments, see Figure 3 The second end cap 13 is provided with a second reinforcing rib 133, which extends from one end of the second end cap 13 to the other end along the second direction Y. The second screw groove 131 and the second receiving groove 132 are both provided at one end of the second reinforcing rib 133. In this embodiment, the provision of the second reinforcing rib 133 can reduce the risk of deformation of the second end cap 13, increase the strength of the second end cap 13, and thus improve the pressure-bearing capacity of the second end cap 13.

[0040] In some embodiments, see Figure 3The second reinforcing ribs 133 are provided in a plurality, and are spaced apart along the third direction Z. Furthermore, the second reinforcing ribs 133 extend from one end of the second end cap 13 to the other end along the second direction Y. In this embodiment, the provision of the plurality of second reinforcing ribs 133 further enhances the strength of the second end cap 13, thereby further enhancing the compressive strength of the second end cap 13.

[0041] In some embodiments, see Figure 1 and Figure 2 There are multiple first fixing bars 14, first screw assemblies 16, and second screw assemblies 17. The multiple first fixing bars 14 are spaced apart along the third direction Z. One end of each first fixing bar 14 is screwed and fixed to the first end cover 12 via a first screw assembly 16, and the other end of each first fixing bar 14 is screwed and fixed to the second end cover 13 via a second screw assembly 17. In this embodiment, by providing multiple first fixing bars 14, the stability of the fixation of the multiple battery cells 11 can be improved. When the battery cells 11 expand, the shear force between the first fixing bars 14 and the first end cover 12 and between the first fixing bars 14 and the second end cover 13 can be dispersed to the multiple first screw assemblies 16 or the multiple second screw assemblies 17, thereby further reducing the risk of the first screw assembly 16 or the second screw assembly 17 being severed under the action of the shear force.

[0042] In some embodiments, see Figure 8A third through hole 151 is provided at one end of the second fixing bar 15, and a third screw groove 124 and a third receiving groove 125 are provided at the end of the first end cap 12 away from the first receiving groove 122. The third screw groove 124 is connected to the bottom of the third receiving groove 125. The third screw assembly 18 includes a third reinforcement member 181 and a third screw member 182. The third reinforcement member 181 includes a third plug-in portion 1811 and a third abutment portion 1812. One end of the third plug-in portion 1811 is connected to the third abutment portion 1812. When viewed along the second direction Y, the diameter of the third receiving groove 125 is larger than the nominal diameter of the third screw groove 124. The third plug-in portion 1811 passes through the third through hole 151 and is inserted into the third receiving groove 125. The third abutment portion 1812 abuts against the surface of the second fixing bar 15 away from the third receiving groove 125. The third reinforcement 181 is also provided with a third fixing hole 1813, and the third fixing hole 1813 passes through the third plug-in portion 1811 and the third abutment portion 1812 along the second direction Y. The third screw member 182 passes through the third fixing hole 1813 and the third receiving groove 125 in sequence and is screwed and fixed with the third screw groove 124, thereby fixing the second fixing strip 15, the third reinforcement 181 and the first end cover 12 to each other. Among them, the diameter of the third plug-in portion 1811 is roughly equal to that of the third receiving groove 125, so that the third plug-in portion 1811 can be inserted into the third receiving groove 125, and the third receiving groove 125 can limit the movement of the third plug-in portion 1811 perpendicular to the second direction Y. When the battery cell 11 expands, the shear force along the third direction Z formed between the first end cover 12 and the second fixing bar 15 can directly act on the third reinforcement 181, thereby reducing the shear force borne by the third screw connector 182, reducing the risk of the third screw connector 182 being cut off under the action of the shear force after the battery cell 11 expands, and improving the stability of the fixation between the second fixing bar 15 and the first end cover 12.

[0043] In some embodiments, see Figure 9A fourth through hole 152 is provided at the end of the second fixing bar 15 away from the first end cap 12, and a fourth screw groove 134 and a fourth receiving groove 135 are provided at the end of the second end cap 13 away from the second receiving groove 132. The fourth screw groove 134 is connected to the bottom of the fourth receiving groove 135. The fourth screw assembly 19 includes a fourth reinforcement member 191 and a fourth screw member 192. The fourth reinforcement member 191 includes a fourth plug-in portion 1911 and a fourth abutting portion 1912. One end of the fourth plug-in portion 1911 is connected to the fourth abutting portion 1912. When viewed along the second direction Y, the diameter of the fourth receiving groove 135 is larger than the nominal diameter of the fourth screw groove 134. The fourth plug-in portion 1911 passes through the fourth through hole 152 and is inserted into the fourth receiving groove 135. The fourth abutting portion 1912 abuts against the surface of the second fixing bar 15 facing away from the fourth receiving groove 135. The fourth reinforcement 191 is also provided with a fourth fixing hole 1913, and the fourth fixing hole 1913 passes through the fourth plug-in portion 1911 and the fourth abutment portion 1912 along the second direction Y. The fourth screw member 192 passes through the fourth fixing hole 1913 and the fourth receiving groove 135 in sequence and is screwed and fixed with the fourth screw groove 134, thereby fixing the second fixing strip 15, the fourth reinforcement 191 and the second end cover 13 to each other. Among them, the diameters of the fourth plug-in portion 1911 and the fourth receiving groove 135 are roughly equal, so that the fourth plug-in portion 1911 can be inserted into the fourth receiving groove 135, and the fourth receiving groove 135 can limit the movement of the fourth plug-in portion 1911 perpendicular to the second direction Y. When the battery cell 11 expands, the shear force along the fourth direction formed between the second end cover 13 and the second fixing bar 15 can directly act on the fourth reinforcement 191, thereby reducing the shear force borne by the fourth screw member 192, reducing the risk of the fourth screw member 192 being cut off under the action of the shear force after the battery cell 11 expands, and improving the stability of the fixation between the second fixing bar 15 and the second end cover 13.

[0044] In some embodiments, see Figure 2 and Figure 3 There are multiple second fixing bars 15, third screw assemblies 18, and fourth screw assemblies 19. The multiple second fixing bars 15 are spaced apart along the third direction Z. One end of a second fixing bar 15 is screwed and fixed to the first end cap 12 via a third screw assembly 18, and the other end of a second fixing bar 15 is screwed and fixed to the second end cap 13 via a fourth screw assembly 19. In this embodiment, by providing multiple second fixing bars 15, the stability of the fixation of the multiple battery cells 11 can be improved. When the battery cells 11 expand, the shear force between the second fixing bars 15 and the first end cap 12 and between the second fixing bars 15 and the second end cap 13 can be dispersed to the multiple third screw assemblies 18 or the multiple fourth screw assemblies 19, thereby further reducing the risk of the third screw assemblies 18 or the fourth screw assemblies 19 being severed under the action of the shear force.

[0045] In some embodiments, see Figure 6 The battery pack 100 further includes a first insulating member 20 , which is generally plate-shaped. Along the second direction Y, the first insulating member 20 is located between the first fixing bar 14 and the plurality of battery cells 11 , thereby reducing the risk of the first fixing bar 14 short-circuiting the plurality of battery cells 11 .

[0046] In some embodiments, see Figure 8 The battery pack 100 further includes a second insulating member 21 , which is generally plate-shaped. Along the second direction Y, the second insulating member 21 is located between the second fixing bar 15 and the plurality of battery cells 11 , thereby reducing the risk of the second fixing bar 15 short-circuiting the plurality of battery cells 11 .

[0047] To help readers better understand the concept of this application, the following is a force analysis of the battery pack 100 at the connection between the first end cap 12, the first fixing bar 14 and the first screw assembly 16. Readers should understand that the forces at other locations (such as the second screw assembly 17) are similar to those at the first screw assembly 16. The force analysis at other screw assemblies will not be described in detail in this article. Figure 10 When the battery cell 11 expands, the first end cap 12 tends to move along the first direction X relative to the first fixing bar 14, so that the first reinforcement 161 is subjected to a shear force F1 exerted by the first end cap 12. The friction force between the first fixing bar 14, the first end cap 12, and the first screw assembly 16 is F2. Assuming that the expansion force of the battery cell 11 is F3, and the total number of the first screw assembly 16, the second screw assembly 17, the third screw assembly 18, and the fourth screw assembly 19 is a, then F1, F2, and F3 satisfy the following relationship:

[0048] F3=a*(F1+F2)

[0049] From the perspective of material mechanics, F1 is the ultimate shear force of a single first reinforcement member 161 to restrain the expansion of the battery cell 11, which can be calculated by the following formula:

[0050] F1=τ*A=τ*π*(Rr) 2

[0051] When the first fixing bar 14 is pulled by the expansion force, there is a friction force F2 between the contact surface of the first end cover 12 and the first screw component 16. F2 can be regarded as the static friction force at normal state. Assuming that the locking force of the first screw component 162 is N and the deadweight is ignored, the calculation formula of the friction force F2 is:

[0052] F2=μ*N

[0053] Wherein, a is the total number of the first screw assembly 16, the second screw assembly 17, the third screw assembly 18 and the fourth screw assembly 19, τ is the ultimate shear stress of the first plug-in portion 1611, A is the cross-sectional area of the first plug-in portion 1611 in the first reinforcement 161, R is the outer radius of the first plug-in portion 1611, r is the radius of the first fixing hole 1613, and μ is the friction coefficient between the first screw assembly 16, the first end cover 12 and the first fixing bar 14.

[0054] The above force analysis indicates that the ultimate shear stress [τ] of the first plug-in connector 1611 is related to the maximum expansion force of the battery pack 100. When this maximum expansion force is exceeded, the first plug-in connector 1611 deforms or breaks, and the subsequent expansion force of the battery cell 11 is borne by the first screw connector 162. Once the expansion force exceeds the ultimate shear stress of the first screw connector 162, a cross-section fracture may occur, damaging the structure of the battery pack 100 and potentially leading to the risk of short circuits, fire, or even explosion.

[0055] Therefore, in order to reduce the risk of cross-sectional fracture of the first screw connector 162, on the one hand, the cross-sectional area A of the first plug-in portion 1611 can be increased; on the other hand, a material with high yield strength can be selected to make the first reinforcement 161, such as chromium, tungsten, titanium, nickel alloy carbon steel, etc.

[0056] In an embodiment of the present invention, a plurality of battery cells 11 are stacked, a first end cap 12 and a second end cap 13 are respectively arranged at both ends of the plurality of battery cells 11, and the first end cap 12 and the second end cap 13 are respectively abutted against the two outermost battery cells 11, one end of the first fixing bar 14 is screwed and fixed to the first end cap 12 by a first screw assembly 16, the other end of the first fixing bar 14 is screwed and fixed to the second end cap 13 by a second screw assembly 17, one end of the second fixing bar 15 is screwed and fixed to the first end cap 12 by a third screw assembly 18, and the other end of the second fixing bar 15 is screwed and fixed to the second end cap 13 by a fourth screw assembly 19, and along the second direction Y, the first fixing bar 14 and the second fixing bar 15 are respectively located on both sides of the plurality of battery cells 11, thereby achieving bundling and fixation between the plurality of battery cells 11. Compared with the method of fixing with steel strips, in the present application, there is no need to use tooling equipment to compress the plurality of battery cells 11 and then put on the steel strips, thereby reducing the difficulty of assembling the battery pack 100.

[0057] The present invention further provides an embodiment of an energy storage device, which includes the above-mentioned battery pack 100. The specific structure and function of the battery pack 100 can be found in the above-mentioned embodiment and will not be described in detail here.

[0058] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A battery pack, characterized in that: include: A plurality of battery cells, wherein the plurality of battery cells are stacked in sequence; a first end cap and a second end cap, wherein the first end cap and the second end cap are respectively located at two ends of the plurality of battery cells, and the first end cap and the second end cap respectively abut the two outermost battery cells along a first direction parallel to the stacking direction of the plurality of battery cells; A first fixing bar, one end of which is screwed and fixed to the first end cover via a first screw assembly, and the other end of which is screwed and fixed to the second end cover via a second screw assembly; a second fixing bar, one end of which is screwed and fixed to the first end cover via a third screw assembly, and the other end of which is screwed and fixed to the second end cover via a fourth screw assembly; Wherein, along the second direction, the first fixing bar and the second fixing bar are respectively located on both sides of the plurality of battery cells, and the second direction is perpendicular to the first direction.

2. The battery pack according to claim 1, wherein: A first through hole is provided at one end of the first fixing bar, a first screw groove is provided at the first end cover, and the first screw connection component is passed through the first through hole and screwed and fixed to the first screw groove.

3. The battery pack according to claim 2, wherein: The first screw connection assembly includes a first reinforcement member and a first screw connection member, the first reinforcement member includes a first plug-in portion and a first abutment portion, and one end of the first plug-in portion is connected to the first abutment portion; The first end cover is provided with a first receiving groove, the first screw groove is connected to the first receiving groove, the first plug-in portion is passed through the first through hole and is at least partially inserted into the first receiving groove, the first abutting portion abuts against the surface of the first fixing bar facing away from the first receiving groove, and the first screw connection member is passed through the first reinforcement member along the second direction and is screwed and fixed to the first screw groove.

4. The battery pack according to claim 3, wherein: The first end cover is provided with a first reinforcing rib, and the first receiving groove is provided at one end of the first reinforcing rib.

5. The battery pack according to claim 1, wherein: A second through hole is provided at one end of the first fixing bar away from the first end cover, a second screw groove is provided at the second end cover, and the second screw connection component is passed through the second through hole and screwed and fixed to the second screw groove.

6. The battery pack according to claim 5, characterized in that The second screw connection assembly includes a second reinforcement member and a second screw connection member, the second reinforcement member includes a second plug-in portion and a second abutment portion, and one end of the second plug-in portion is connected to the second abutment portion; The second end cover is provided with a second receiving groove, the second screw groove is connected to the second receiving groove, the second plug-in portion is passed through the second through hole and is at least partially inserted into the second receiving groove, the second abutting portion abuts against the surface of the second fixing bar facing away from the second receiving groove, and the second screw connection member is passed through the second reinforcement member along the second direction and is screwed and fixed to the second screw groove.

7. The battery pack according to claim 6, characterized in that: The second end cover is provided with a second reinforcing rib, and the second receiving groove is provided at one end of the second reinforcing rib.

8. The battery pack according to claim 1, wherein: The battery pack further includes a first insulating member. Along the second direction, the first insulating member is located between the first fixing bar and the plurality of battery cells.

9. The battery pack according to claim 1, wherein: The battery pack further includes a second insulating member. Along the second direction, the second insulating member is located between the second fixing bar and the plurality of battery cells.

10. An energy storage device, characterized in that: A battery pack comprising the battery pack according to any one of claims 1 to 9.

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