Battery pack

Abstract

A battery pack, characterized in that it comprises a housing, a battery assembly, and a fastening band. The housing has a bottom plate and a peripheral frame arranged around the outer periphery of the bottom plate. A receiving space is formed between the bottom plate and the peripheral frame. The fastening band is laid on the bottom plate. The battery assembly is placed in the receiving space and is fastened to the bottom plate via the fastening band. The battery assembly comprises a battery cell and an insulating film. The battery cell has a first end surface and a second end surface arranged opposite to each other, and a first side surface, a second side surface, a third side surface, and a fourth side surface arranged between the first end surface and the second end surface and connected sequentially. The first side surface is arranged opposite to the third side surface.the second side surface is arranged opposite to the fourth side surface, the regions at the two ends of the insulating film are a start section and an end section, respectively, the insulating film is applied to the outside of the first side surface, the second side surface, the third side surface and the fourth side surface, the start section is attached to the outside of the first side surface, the end section, facing away from the first side surface, is attached to a side of the start section, an overlapped region of the start section and the end section is an overlap section, a side of the battery cell arranged on the first side surface is glued to the base plate via the fastening tape, a direction from the second side surface to the fourth side surface is a first direction, in the first direction a dimension of the overlap section "L, I“ mm, a dimension of the first side surface is “L2” mm, a thickness of the insulating film is “a” mm, where 0.028≤a*(L1 / L2)≤0.12.

Description

TECHNICAL FIELD

[0001] The present utility model relates to the technical field of batteries, in particular to a battery pack. STATE OF THE ART

[0002] A battery pack comprises a casing and a battery assembly. The battery assembly is secured to the bottom wall of the casing by a fastening tape. The battery assembly is formed by stacking multiple battery cells. To protect the battery cells, an insulating film is wrapped around the outer surface of the battery cells. The insulating film has a starting section and an end section. The starting section is attached to the outer surface of the battery cells, and to wrap the battery cells, the end section then wraps around the battery cells and is stacked on the side facing away from the battery cells, on the starting section side.

[0003] The battery pack is subject to post-engineering requirements regarding its weight and dimensions, which determine the adhesive quantity used for the fastening tape and the installation height of the battery assembly. Therefore, if the insulating film is relatively thick, the fastening tape will overstretch during battery installation, resulting in significant adhesive overflow. If the insulating film is relatively thin, the fastening tape may not be able to fully cover the adhesive surface of the insulating film of the battery cells during battery installation, thereby compromising the bond strength. SUMMARY OF THE UTILITY MODEL

[0004] The subject matter of the present utility model is to provide a battery pack to ensure the stability of the battery assembly in the housing and to prevent adhesive overflow.

[0005] To solve the above technical problems, the present utility model provides the following technical solutions: A battery pack comprises a housing, a battery assembly, and a fastening band. The housing has a bottom plate and a peripheral frame arranged around the outer periphery of the bottom plate. A receiving space is formed between the bottom plate and the peripheral frame. The fastening band is laid on the bottom plate. The battery assembly is placed in the receiving space and fastened to the bottom plate via the fastening band. The battery assembly comprises a battery cell and an insulating film. The battery cell has a first end surface and a second end surface arranged opposite to each other, and a first side surface, a second side surface, a third side surface, and a fourth side surface arranged between the first end surface and the second end surface and connected sequentially. The first side surface is arranged opposite to the third side surface.The second side surface is arranged opposite the fourth side surface. The regions at the two ends of the insulating film are a starting section and an end section, respectively. The insulating film is applied to the outer side of the first side surface, the second side surface, the third side surface, and the fourth side surface. The starting section is attached to the outer side of the first side surface. The end section is attached to a side of the starting section, facing away from the first side surface. An overlapped region of the starting section and the end section is an overlap section. A side of the battery cell arranged on the first side surface is bonded to the base plate via the fastening tape. A direction from the second side surface to the fourth side surface is a first direction. In the first direction, a dimension of the overlap section is "L1" mm, a dimension of the first side surface is "L2" mm.a thickness of the insulating film “a” mm, where 0.028≤a*(L1 / L2)≤0.12.,

[0006] The battery pack of the present utility model has the following advantageous effects compared to the prior art: In the present utility model, the insulating film is wrapped around the outside of the battery cell, and the starting portion and ending portion of the insulating film are arranged on the first side surface of the battery cell. Therefore, when the first side surface of the battery cell is bonded with the fixing tape, warpage of the ending portion of the insulating film can be prevented and the stability of the battery cell bonded to the bottom plate can be ensured. In addition, after the battery pack design is completed, the amount of fixing tape used and the installation height of the battery assembly within the case are required. Under this premise, if the insulating film thickness is relatively thick, it is easy to overstretch the fixing tape and cause adhesive overflow, so in this case, the dimension of the overlap portion needs to be reduced.With a relatively thin insulating film thickness, this may compromise the bonding area between the battery cell and the fastening tape, so the overlap dimension needs to be increased in this case. This maintains a value of 0.028≤a*(L1 / L2)≤0.12, so that the battery assembly can be stably bonded to the base plate without causing adhesive overflow. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of the overall structure of the embodiment of the present utility model; Fig. Fig. 2 is another perspective view of the overall structure of the embodiment of the present utility model; Fig. 3 is a cross-sectional view of the overall structure of the embodiment of the present utility model; Fig. 4 is an enlarged view of part “A” in Fig. 3; Fig. 5 is a schematic diagram of a battery cell and an insulating film of the embodiment of the present utility model; Fig. 6 is an exploded view of a battery cell and an insulating film of the embodiment of the present utility model; Fig. 7 is an enlarged view of part “B” in Fig. 6; Fig. 8 is an exploded view of a battery cell and an insulating film of the embodiment of the present utility model; Fig. 9 is a front view of a battery cell of the embodiment of the present utility model; Fig. 10 is an enlarged view of part “C” in Fig. 9; Fig. 11 is a schematic diagram of the welding seam of a battery cell of the embodiment of the present utility model; Fig. 12 is a bottom view of a battery cell of the embodiment of the present utility model. In the figures:

[0007] 1. Casing; 11. Bottom plate; 12. Surrounding frame; 13. Receiving space; 2. Battery assembly; 21. Battery cell; 211. First end face; 212. Second end face; 213. First side face; 214. Second side face; 215. Third side face; 216. Fourth side face; 217. Casing; 218. Cover plate; 22. Insulating film; 221. Starting section; 222. End section; 223. Overlapping section; 3. Fixing band; 4. Weld seam. DETAILED DESCRIPTION OF EMBODIMENTS

[0008] The specific implementation of the present utility model is described in more detail below in conjunction with the attached drawings and examples. The following examples serve to illustrate the present utility model, but are not intended to limit the scope of protection of the present utility model.

[0009] It should be noted that in the description of the present utility model, the term "include / comprise" used in the specification of the present utility model refers to the presence of the features, integers, steps, operations, parts / components, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, parts / components, components, and / or groups thereof. It should be noted that when a part / component is described as being "connected" to another part / component, it may be directly connected to other parts / components, or intermediate parts / components may be present. The term "and / or" used here includes all or any unit and all combinations of one or more related recited elements.

[0010] As in the Fig. 1 to 12, the present utility model relates to a battery pack comprising a housing 1, a battery assembly 2, and a fastening band 3. The housing 1 has a bottom plate 11 and a peripheral frame 12 arranged around the outer periphery of the bottom plate 11. A receiving space 13 is formed between the bottom plate 11 and the peripheral frame 12, and the fastening band 3 is laid on the bottom plate 11. The battery assembly 2 is positioned in the receiving space 13 and adhered to the bottom plate 11 via the fastening band 3. The battery assembly 2 has a battery cell 21 and an insulating film 22.The battery cell 21 has a first end surface 211 and a second end surface 212 arranged opposite each other, and a first side surface 213, a second side surface 214, a third side surface 215, and a fourth side surface 216 arranged between the first end surface 211 and the second end surface 212 and connected sequentially. The first side surface 213 is arranged opposite the third side surface 215, and the second side surface 214 is arranged opposite the fourth side surface 216. The regions at the two ends of the insulating film 22 are a start portion 221 and an end portion 222, respectively. The insulating film 22 is applied to the outside of the first side surface 213, the second side surface 214, the third side surface 215, and the fourth side surface 216.The starting section 221 is attached to the outside of the first side surface 213, and the end section 222 is attached to a side of the starting section 221, facing away from the first side surface 213. An overlapped area of ​​the starting section 221 and the end section 222 is an overlap section 223. A side of the battery cell 21 arranged on the first side surface 213 is glued to the base plate 11 via the fastening tape 3. A direction from the second side surface to the fourth side surface is a first direction, in the first direction, a dimension of the overlap portion is “L1” mm, a dimension of the first side surface is “L2” mm, a thickness of the insulating film is “a” mm, where 0.028≤a*(L1 / L2)≤0.12, and the value of a*(L1 / L2) may be 0.04, 0.06, 0.08, or 0.1.

[0011] In the present utility model, the insulating film 22 is wrapped around the outside of the battery cell 21, and the starting portion 221 and the end portion 222 of the insulating film 22 are arranged on the first side surface 213 of the battery cell 21. Therefore, when the first side surface 213 of the battery cell 21 is bonded to the fixing tape 3, warpage of the end portion 222 of the insulating film 22 can be prevented and the stability of the battery cell 21 bonded to the bottom plate 11 can be ensured. Furthermore, after the battery pack design is completed, the amount of the fixing tape 3 used and the installation height of the battery assembly 2 in the case 1 are required. Under this premise, if the insulating film 22 is relatively thick, it is easy to overstretch the fixing tape 3 and cause adhesive overflow, so in this case, the dimension of the overlap portion 223 needs to be reduced.If the thickness of the insulating film 22 is relatively small, this may impair the bonding area between the battery cell 21 and the fixing tape 3, so the dimension of the overlap portion 223 needs to be increased in this case. This maintains 0.028≤a*(L1 / L2)≤0.12, so that the battery assembly 2 can be stably bonded to the base plate 11 without causing adhesive overflow.

[0012] Note that the area at one end of the insulating film 22 is the starting portion 221, and the area at the other end of the insulating film 22 is the ending portion 222. When applying the insulating film 22 to the outside of the battery cell 21, first, the starting portion 221 of the insulating film 22 is attached to the first side surface 213, and then the ending portion 222 of the insulating film 22 sequentially passes the second side surface 214, the third side surface 215, and the fourth side surface 216, and is finally attached to the side of the starting portion 221 on the first side surface 213, facing away from the first side surface 213. The area where the starting portion 221 and the ending portion 222 overlap is the overlap portion 223.

[0013] In some embodiments, 4mm≤L1≤40mm, 8mm≤L2≤80mm. The value of "L1" can be 8mm, 13mm, 18mm, 22mm, 29mm, 33mm, or 38mm, and the value of "L2" can be 15mm, 25mm, 35mm, 45mm, 65mm, or 75mm.

[0014] In some embodiments, 0.05≤L1 / L2≤0.95. The value of "L1 / L2" may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9.

[0015] In some embodiments, 0.05 mm≤A≤0.5 mm. The value of "a" can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.45 mm.

[0016] In some embodiments, 0.04≤a*(L1 / L2)≤0.11.

[0017] In the present embodiment, the thickness of the fastening tape 3 is “c” mm, 0.3 mm≤c≤3 mm, 0.05 mm≤a≤0.2 mm, and the value of “c” may be 0.6 mm, 0.9 mm, 1.2 mm, 1.8 mm, 2.2 mm, 2.6 mm or 2.8 mm.

[0018] If the thickness of the insulating film 22 is relatively thick, the thermal conductivity will be low, so the thickness of the fixing tape 3 must be thinner to allow easy heat dissipation from the battery cell 21; if the thickness of the insulating film 22 is relatively thin, the thermal conductivity will be better. In this case, the thickness of the fixing tape 3 can be appropriately increased to improve the adhesion strength of the battery assembly 2. Therefore, 0.3 mm ≤ c ≤ 3 mm, 0.05 mm ≤ a ≤ 0.2 mm is maintained to meet the adhesion strength requirements of the battery assembly 2 and the thermal conductivity requirements of the battery assembly 2.

[0019] In the present embodiment, the battery cell 21 includes a casing 217 and a cover plate 218. The two ends of the casing 217 are openings. Two cover plates 218 are arranged, and the two cover plates 218 are designed to cover the openings at the two ends of the casing 217, respectively, and the first end surface 211 and the second end surface 212 are formed accordingly. The four sides of the casing 217 correspond to the first side surface 213, the second side surface 214, the third side surface 215, and the fourth side surface 216. The casing 217 is arranged with a weld line 4 on the first side surface 213 in a direction from the first end surface 211 to the second end surface 212.

[0020] During the manufacture of the housing 217, two ends of the planar structure are welded together to form the housing 217. In this case, a weld seam 4 is formed on one side of the housing 217. The weld seam 4 is arranged on the first side surface 213 of the housing 217, and the first side surface 213 of the housing 217 is bonded to the fastening tape 3, so that the fastening tape 3 can be used to reinforce the strength of the weld seam 4 to improve the structural stability of the battery cell 21.

[0021] In one embodiment, there is no overlap of the positive projection of the overlap portion 223 on the first side surface 213 with the positive projection of the weld seam 4 on the first side surface 213. In this case, 0.05≤a*(L1 / L2)≤0.12 is maintained.

[0022] Since the weld seam 4 also protrudes from the first side surface 213, if the overlap portion 223 covers the weld seam 4, the overlap portion 223 will protrude too far from the first side surface 213, so that it will cause a strong adhesive overflow after bonding with the fastening tape 3.

[0023] In another embodiment, there is an overlap of the orthogonal projection of the overlap portion 223 on the first side surface 213 with the orthogonal projection of the weld seam 4 on the first side surface 213. In this case, 0.028≤a*(L1 / L2)≤0.1 is maintained.

[0024] Since there are many burrs on the weld seam 4, when the overlap portion 223 covers the weld seam 4, double protection can be formed to prevent the burrs from piercing the insulating film 22 and reduce the risk of insulation failure.

[0025] As in Fig.12, in the present embodiment, in the direction from the first end face 211 to the second end face 212, a dimension of the insulating film 22 is “L3” mm and a dimension of the battery cell 21 is “L4” mm, where 0.6≤L3 / L4≤1, 0.05≤a*(L1 / L2)≤0.12, and the value of “L3 / L4” may be 0.65, 0.7, 0.75, 0.8, 0.85, or 0.9.

[0026] When "L3 / L4" is small, the battery cell 21 is partially exposed outside the insulating film 22, and the exposed part of the battery cell 21 is bonded to the fixing tape 3, and the adhesion strength is also good. Therefore, the values ​​of "a" and "L1 / L2" can be smaller, which can improve the stability of the battery assembly 2 in the casing 1; when "L3 / L4" is large, the exposed part of the battery cell 21 is small, and the adhesion strength of the battery cell 21 is also poor. Therefore, the values ​​of "a" and "L1 / L2" must be larger, while maintaining 0.05≤a*(L1 / L2)≤0.12, to improve the stability of the battery assembly 2 in the casing 1.

[0027] In the present embodiment, the insulating film 22 is made of PP, PE, PET or PC.

[0028] In one embodiment, the insulating film 22 is hot-melt bonded to the outside of the battery cell 21.

[0029] That is, the insulating film 22 is applied to the outside of the battery cell 21 and hot-melt bonded, and the end portion 222 of the insulating film 22 is hot-melt bonded to one side of the start portion 221 of the insulating film 22, facing away from the battery cell 21, in order to improve the stability of the insulating film 22 outside the battery cell 21.

[0030] In another embodiment, the starting portion 221 of the insulating film 22 is hot-melt bonded to the outside of the first side surface 213, and the end portion 222 of the insulating film 22 is hot-melt bonded to one side of the starting portion 221 of the insulating film 22, facing away from the first side surface 213.

[0031] That is, only the starting portion 221 of the insulating film 22 is hot-melt bonded to the first side surface 213 of the battery cell 21, and then the end portion 222 of the insulating film 22, facing away from the first side surface 213, is hot-melt bonded to one side of the starting portion 221 of the insulating film 22. The area between the starting portion 221 and the end portion 222 of the insulating film 22 is tightly wrapped around the battery cell 21, so that the insulating film 22 can also be applied to the outside of the battery cell 21.

[0032] In other embodiments, the starting portion 221 of the insulating film 22 is attached to the first side surface 213. After the insulating film 22 has been wrapped around the second side surface 214, the third side surface 215, and the fourth side surface 216, the insulating film 22 is tightened such that the end portion 222 of the insulating film 22, facing away from the first side surface 213, is hot-melt bonded to one side of the starting portion 221, so that the insulating film 22 is tightly applied to the outside of the battery cell 21.

[0033] In the present embodiment, the areas of the second side surface 214 and the fourth side surface 216 are both larger than the area of ​​the first side surface 213.

[0034] Specifically, the areas of the first side surface 213 and the third side surface 215 are equal, the areas of the second side surface 214 and the fourth side surface 216 are equal, and the areas of the second side surface 214 and the fourth side surface 216 are both larger than the area of ​​the first side surface 213. That is, the first side surface 213 of the battery cell 21 is bonded to the bottom plate 11 via the fixing tape 3, which can improve the arrangement density of the battery assembly 2.

[0035] In the present embodiment, the first end surface 211 and the second end surface 212 can be a flat or a curved surface. The areas of the first side surface 213, the second side surface 214, the third side surface 215, and the fourth side surface 216 are all larger than the areas of the first end surface 211 and the second end surface 212.

[0036] The above is only a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the technical principle of the present utility model, and these improvements and substitutions should also be considered within the scope of the present utility model.

Claims

[1] Battery pack, characterized bythat it comprises a housing, a battery assembly and a fastening strap, the housing comprising a base plate and a circumferential frame arranged around the outer circumference of the base plate, a receiving space formed between the base plate and the circumferential frame, the fastening strap laid on the base plate, the battery assembly placed in the receiving space and attached to the base plate via the fastening strap, the battery assembly comprising a battery cell and an insulating film, the battery cell comprising a first end face and a second end face arranged opposite each other, and a first side face, a second side face, a third side face and a fourth side face arranged between the first end face and the second end face and sequentially connected, the first side face being arranged opposite the third side face,the second side surface is arranged opposite the fourth side surface, the areas at the two ends of the insulating film are a start section and an end section respectively, the insulating film is applied to the outside of the first side surface, the second side surface, the third side surface and the fourth side surface, the start section is attached to the outside of the first side surface, the end section, facing away from the first side surface, is attached to one side of the start section, an overlapping area of ​​the start section and the end section is an overlap section, a side of the battery cell arranged on the first side surface is bonded to the base plate via the fastening tape, a direction from the second side surface to the fourth side surface is a first direction, in the first direction a dimension of the overlap section “L, I“ mm is, a dimension of the first side surface “L2” is mm, a thickness of the insulating film “a” is mm, where 0.028≤a*(L1 / L2)≤0.

12. [2] Battery pack according to claim 1, characterized by , that 4mm≤L1≤40mm, 8mm≤L2≤80mm. [3] Battery pack according to claim 1, characterized by , that 0.05≤L1 / L2≤0.

95. [4] Battery pack according to claim 1, characterized by , that 0.05mm≤a≤0.5mm. [5] Battery pack according to claim 1, characterized by that 0.04≤a*(L1 / L2)≤0.

11. [6] Battery pack according to claim 1, characterized by , that the thickness of the fastening tape “c” is mm, 0.3mm≤c≤3mm, 0.05mm≤a≤0.2mm. [7] Battery pack according to claim 1, characterized by, that the battery cell has a housing and a cover plate, wherein two ends of the housing are openings, two cover plates are arranged and the two cover plates are covered accordingly at the openings at the two ends of the housing, and the first end surface and the second end surface are designed accordingly, the four sides of the housing correspond to the first side surface, the second side surface, the third side surface and the fourth side surface, and the housing is provided with a weld seam on the first side surface in a direction from the first end surface to the second end surface. [8] Battery pack according to claim 7, characterized by , that the orthogonal projection of the overlap section on the first side surface does not overlap the orthogonal projection of the weld seam on the first side surface, 0.05≤a*(L1 / L2)≤0.

12. [9] Battery pack according to claim 7, characterized by, that the orthogonal projection of the overlap section on the first side surface overlaps the orthogonal projection of the weld on the first side surface, and 0.028≤a*(L1 / L2)≤0.

1. [10] Battery pack according to claim 1, characterized by , that in one direction from the first end surface to the second end surface, one dimension of the insulating film “L3” is mm and one dimension of the battery cell “L4” is mm, where 0.6≤L3 / L4≤1, 0.05≤a*(L1 / L2)≤0.

12. [11] Battery pack according to claim 1, characterized by , that the areas of the second and fourth faces are both larger than the area of ​​the first face.

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