Battery packs and electrical devices

Abstract

This utility model relates to the field of batteries and discloses a battery pack and an electrical device. The battery pack includes a housing, multiple battery cells, and structural adhesive. Each battery cell includes a shell and an insulating film. The outer surface of the insulating film is grid-like or striped. The insulating film includes a first outer surface and a second outer surface. The second outer surface of the battery cell is bonded to the bottom wall, the first outer surface of the battery cell near the side wall is bonded to the side wall, and the first outer surfaces of two adjacent battery cells are bonded together with structural adhesive. The bonding surface area between the first outer surface and the structural adhesive is S1, and the bonding surface area between the second outer surface and the structural adhesive is S2. Along the second direction, the height of the structural adhesive above the second outer surface is H. Along the third direction, the shear strength between the insulating film and the structural adhesive is σ, which satisfies 800 mm. 2 ≤S1≤3500mm 2 3000mm 2 ≤S2≤10000mm 2 , 3Mpa≤σ≤4.5Mpa, 2mm≤H≤5mm, 4.0*10 4 N·mm≤(S1+S2)*σ*H≤1.5*10 5 N·mm. By using a reasonable amount of structural adhesive, the bonding strength between the insulating film and the structural adhesive is ensured, reducing the risk of cell detachment and lowering costs.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to battery packs and electrical devices. Background Technology

[0002] Battery packs are widely used in various fields such as transportation power supply, power storage, new energy storage power supply, aerospace and military industries due to their advantages such as large capacity, high operating voltage, strong charge retention capability and long cycle life.

[0003] A battery pack typically consists of a housing and multiple battery cells housed within it. Each cell is covered with an insulating film (such as a blue film) to provide insulation and protection. The cells are secured together with structural adhesive to reduce the risk of collisions. However, when the battery pack is subjected to mechanical vibration or impact, the adhesion between the insulating film and the structural adhesive can fail, leading to cell detachment. Utility Model Content

[0004] In view of this, the present invention provides a battery pack and power supply device, which ensures the bonding strength between the insulating film and the structural adhesive by using a reasonable amount of structural adhesive, thereby reducing the risk of battery cell detachment and reducing costs.

[0005] In a first aspect, this utility model provides a battery pack, comprising: a housing, including a bottom wall and two side walls connected to opposite sides of the bottom wall along a first direction; a plurality of battery cells disposed within the housing and arranged along the first direction, each battery cell including a shell and an insulating film enclosing the shell, the outer surface of the insulating film being grid-like or striped, the insulating film including a first outer surface and a second outer surface, the first outer surface corresponding to the surface with the largest area of ​​the shell, and the first outer surfaces of two adjacent battery cells facing each other along the first direction; and structural adhesive, between the second outer surface of each battery cell and the bottom wall, near... The first outer surface of the cell in the sidewall and the sidewall, as well as the first outer surfaces of two adjacent cells, are bonded and fixed by the structural adhesive. The bonding surface area between the first outer surface and the structural adhesive is S1, and the bonding surface area between the second outer surface and the structural adhesive is S2. Along the second direction, the height of the structural adhesive above the second outer surface is H. Along the third direction, the shear strength between the insulating film and the structural adhesive is σ. The first direction, the second direction, and the third direction are mutually perpendicular, and the third direction is the length direction of the cell, satisfying 800mm. 2 ≤S1≤3500mm 2 3000mm 2 ≤S2≤10000mm 2 , 3Mpa≤σ≤4.5Mpa, 2mm≤H≤5mm, 4.0*104 N·mm≤(S1+S2)*σ*H≤1.5*10 5 N·mm.

[0006] Beneficial effects: When the outer surface of the insulating film is grid-like or striped and meets the above parameter requirements, the insulating film and structural adhesive can be reliably bonded with a reasonable amount of adhesive, thereby achieving reliable fixation of the battery cell. At the same time, it can also reduce the overall weight of the battery pack and reduce costs.

[0007] In one optional embodiment, the battery cell is a blade battery cell. Along the first direction, the width of the battery cell is W, 14.5mm≤W≤23mm; along the second direction, the height of the battery cell is H1, 85mm≤H1≤180mm; along the third direction, the length of the battery cell is L, 350mm≤L≤550mm, and the first direction, the second direction, and the third direction are perpendicular to each other; wherein, the structural adhesive completely covers the second outer surface.

[0008] Beneficial effects: For blade-shaped battery cells, a slightly larger amount of structural adhesive is used on the side closest to the bottom wall to maximize the bonding strength and reduce the risk of the battery cell falling off.

[0009] In one alternative implementation, 1200mm 2 ≤S1≤3500mm 2 3000mm 2 ≤S2≤6500mm 2 5.0*10 4 N·mm≤(S1+S2)*σ*H≤1.5*10 5 N·mm.

[0010] Beneficial effects: When the above parameter requirements are met, the insulating film and structural adhesive can be reliably bonded with a reasonable amount of adhesive, thereby achieving reliable fixation of the blade cell. At the same time, it can also reduce the overall weight of the battery pack and reduce costs.

[0011] In one optional embodiment, the battery cell is a prismatic cell, and the structural adhesive partially covers the second outer surface; along the first direction, the width of the battery cell is W′, 25mm≤W′≤75mm; along the third direction, the length of the battery cell is L1, 150mm≤L1≤380mm, and the bonding length between the insulating film and the structural adhesive is L2, 130mm≤L2≤270mm; along the second direction, the height of the battery cell is H2, 90mm≤H2≤130mm.

[0012] Beneficial effects: For square-shell battery cells, the amount of structural adhesive used on the side closest to the bottom wall can be reduced slightly, thus meeting the bonding strength requirements while lowering costs.

[0013] In one alternative implementation, 800mm 2 ≤S1≤1500mm 2 5000mm 2 ≤S2≤10000mm 2 2mm≤H≤4mm, 4.0*10 4 N·mm≤(S1+S2)*σ*H≤1.2*10 5 N·mm.

[0014] Beneficial effects: For prismatic battery cells, the insulation film and structural adhesive can be reliably bonded with a reasonable amount of adhesive, thereby ensuring reliable cell fixation. At the same time, it can also reduce the overall weight of the battery pack and reduce costs.

[0015] In one optional embodiment, the thickness of the structural adhesive is T2, where 0.5mm ≤ T2 ≤ 2mm.

[0016] Beneficial effects: When T2 is greater than or equal to 0.5, the structural adhesive and the outer surface of the insulating film have more sufficient contact, which can increase the contact area and improve the bonding strength; when T2 is less than or equal to 0.5, the amount of structural adhesive can be used reasonably, so that the structural adhesive is not too thick, reducing space occupation and increasing the volumetric energy density of the battery pack 100.

[0017] In one optional embodiment, the thickness of the insulating film is T1, where 0.1 mm ≤ T1 ≤ 0.15 mm.

[0018] Beneficial effects: When T1 is greater than or equal to 0.1mm, a grid or stripe structure can be easily formed on the outer surface of the insulating film, improving manufacturing efficiency and effectively protecting the battery cell; when T1 is less than or equal to 0.15mm, the thickness of the insulating film is not too large, reducing space occupation and increasing the volumetric energy density of the battery pack.

[0019] In one alternative embodiment, the outer surface of the insulating film is frosted.

[0020] Beneficial effect: The frosted surface can further increase the bonding surface area between the insulating film and the structural adhesive, thereby improving the bonding strength between the two.

[0021] In one optional embodiment, the roughness of the frosted surface is Ra, where 1 ≤ Ra ≤ 1.5.

[0022] Beneficial effects: When Ra is greater than or equal to 1, it can increase the bonding surface area between the insulating film and the structural adhesive, thereby improving the bonding strength between the two; when Ra is less than or equal to 1.5, the thickness of the insulating film does not need to be too large to form a frosted surface, making the overall thickness of the insulating film thinner, reducing space occupation, and increasing the volumetric energy density of the battery pack.

[0023] In one alternative embodiment, the housing has an opening on one side; the battery cell also includes an electrode assembly and a cover plate, the cover plate closing the opening so that the cover plate and the housing together form a closed space for accommodating the electrode assembly.

[0024] Beneficial effect: It can better protect the electrode components.

[0025] In one optional embodiment, the insulating film includes an adhesive layer and an insulating layer, the adhesive layer being bonded between the housing and the insulating layer, and the side of the insulating layer facing away from the adhesive layer being the outer surface of the insulating film along the thickness direction of the insulating film.

[0026] Beneficial effects: The insulating film consists of an adhesive layer and an insulating layer, which can be easily and quickly applied to the surface of the housing, improving manufacturing efficiency.

[0027] Secondly, this utility model also provides an electrical device, including: a battery pack as described in any of the above embodiments.

[0028] Beneficial effects: Since the electrical device includes a battery pack, it has the same technical effects as the battery pack, which will not be elaborated here. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present utility model;

[0031] Figure 2 This is an exploded view of the battery cell according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the outer surface of an insulating film according to an embodiment of the present invention;

[0033] Figure 4 for Figure 3 A cross-sectional view cut along the CC axis;

[0034] Figure 5 This is a schematic diagram of the outer surface of another insulating film according to an embodiment of the present invention;

[0035] Figure 6 for Figure 5 Cross-sectional view cut along the middle DD section;

[0036] Figure 7 for Figure 1 Cross-sectional view cut along EE;

[0037] Figure 8 for Figure 7 A magnified view of part A in the middle;

[0038] Figure 9 This is a schematic diagram of another battery pack according to an embodiment of the present utility model, wherein one side wall of the box has been removed for ease of illustration;

[0039] Figure 10 for Figure 9 A structural diagram from another perspective;

[0040] Figure 11 for Figure 10 A magnified view of part B in the middle.

[0041] Explanation of reference numerals in the attached figures:

[0042] 100-Battery pack; 10-Box; 11-Bottom wall; 12-Side wall; 20-Battery cell; 21-Shell; 22-Insulating film; 221-First outer surface; 222-Second outer surface; 223-Adhesive layer; 224-Insulating layer; 23-Electrode assembly; 24-Cover plate; 25-Top patch; 26-Insulating sheet; 30-Structural adhesive; X-First direction; Y-Third direction; Z-Second direction. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0044] Because the outer surface of the insulating film (such as the blue film) wrapped around the battery cell is smooth, the shear strength and pull-out strength between the structural adhesive and the insulating film are both about 1 MPa. The bonding strength between the two is low, which makes it easy for the bonding to fail and cause the battery cell to fall off.

[0045] To address this, the bonding surface area between the insulating film and the structural adhesive is increased by changing the shape of the outer surface of the insulating film, thereby improving the bonding strength between the two and reducing the risk of cell detachment. Furthermore, by using a reasonable amount of structural adhesive, the bonding strength can be met while also reducing the overall weight of the battery pack and lowering costs.

[0046] The following is combined Figures 1 to 11 The following describes embodiments of the present invention.

[0047] According to an embodiment of the present invention, a battery pack 100 is provided, including a housing 10, a plurality of battery cells 20, and structural adhesive 30. The housing 10 includes a bottom wall 11 and two side walls 12 connected to opposite sides of the bottom wall 11 along a first direction X. The plurality of battery cells 20 are disposed within the housing 10 and arranged along the first direction X. Each battery cell 20 includes a housing 21 and an insulating film 22 covering the housing 21. The outer surface of the insulating film 22 is mesh-like. Figure 3 (as shown) or striped ( Figure 5 As shown, the insulating film 22 includes a first outer surface 221 and a second outer surface 222. The first outer surface 221 corresponds to the surface with the largest area of ​​the housing 21. Along the first direction X, the first outer surfaces 221 of the insulating films 22 in two adjacent cells 20 are arranged opposite to each other. The second outer surface 222 of the insulating film 22 in each cell 20 is bonded and fixed to the bottom wall 11 by structural adhesive 30. The first outer surface 221 of the insulating film 22 in the cell 20 near the side wall 12 is bonded and fixed to the side wall 12, and the first outer surface 221 of the insulating film 22 in two adjacent cells is also bonded and fixed by structural adhesive 30.

[0048] The housing 10 is used to house and protect multiple battery cells 20. The bottom wall 11 and two side walls 12 of the housing 10 can form a receiving space for accommodating the multiple battery cells 20. As an example, the housing 10 can be generally U-shaped, with an opening on the side away from the bottom wall 11 along the second direction Z. A top cover can be installed at the opening, which can be a separate component or part of the vehicle chassis.

[0049] The battery cell 20 can be a wound structure or a stacked structure. The battery cell 20 can be a blade battery cell or a prismatic battery cell. The battery cell 20 includes a housing 21 and an electrode assembly 23 disposed within the housing 21. The electrode assembly 23 includes a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrode. The electrode assembly 23 may also be wrapped with an insulating sheet 26, which serves to isolate the electrode assembly 23 from the housing 21.

[0050] In some embodiments, the battery cell 20 may further include a cover plate 24, which can close an opening on one side of the housing 21 to form a closed space for accommodating the electrode assembly 23. This closed space may also contain electrolyte or the like. The cover plate 24 may be provided with electrode posts, explosion-proof valves, and injection holes. A top patch 25 may also be bonded to the cover plate 24. In blade battery cells, refer to... Figure 1 and Figure 2 The casing 21 has an opening on one side along the third direction Y, and the cover plate 24 is located on the opening side, meaning the cell 20 is horizontally positioned. In a prismatic cell, refer to... Figure 9The housing 21 has an opening on the side away from the bottom wall 11 along the second direction Z, and the cover plate 24 is located on the opening side, that is, the battery cell 20 is upright.

[0051] Multiple battery cells 20 are arranged along a first direction X, which can be the width direction (thickness direction) of the battery cells 20. Among the multiple battery cells 20, the surfaces with the largest area in the housing 21 of the battery cell 20 are arranged face-to-face along the first direction X. In this invention, the second direction Z can be the height direction of the battery cell 20, and the third direction Y can be the length direction of the battery cell 20. The first direction X, the second direction Z, and the third direction Y are perpendicular to each other. The cover plate 24 can be disposed on one side of the housing 21 along the third direction Y.

[0052] The insulating film 22 can cover the outer side of the housing 21 and the end face away from the cover plate 24 along the third direction Y, that is, completely cover the housing 21. Of course, the insulating film 22 can also only cover the outer side of the housing 21.

[0053] When the outer surface of the insulating film 22 is grid-like, the grid can be a square grid, a triangular grid, a diamond grid, a circular grid, or an irregularly shaped grid, etc. Figure 3 The example shown is a square grid. The shapes of the grid cells can be the same or different. The depths of the grid cells can be the same or different. When the outer surface of the insulating film 22 is striped, the stripes can be straight stripes, curved stripes, etc. Figure 5 The example shows the case of straight stripes. The shapes of the stripes can be the same or different, and the depths of the stripes can be the same or different. When the stripes are straight stripes, they can be parallel to the length direction of the cell 20, or they can be at an angle to the length direction of the cell 20, i.e., oblique stripes.

[0054] Figure 3 and Figure 5 The diagram shows the grid-like and striped patterns on the outer surface of the insulating film 22 in a blade-shaped battery cell. The shape of the outer surface of the insulating film 22 in a prismatic battery cell can be found by referring to... Figure 3 and Figure 5 Shape of the outer surface of the insulating film 22 in the blade battery cell.

[0055] The outer surface of the insulating film 22 is grid-like or striped, making the outer surface of the insulating film 22 non-smooth and having an uneven structure.

[0056] The insulating film 22 includes a first outer surface 221 and a second outer surface 222. The first outer surface 221 corresponds to the surface of the housing 21 with the largest area. The second outer surface 222 corresponds to the side of the housing 21 near the bottom wall 11 along the second direction Z. As an example, in the square battery cell 20, the housing 21 has two large surfaces opposite each other along the first direction X, two narrow surfaces opposite each other along the second direction Z, and an end face along the third direction Y. The insulating film 22 can cover the two large surfaces, two narrow surfaces, and one end face of the housing 21, with the first outer surface 221 corresponding to the large surface of the housing 21 and the second outer surface 222 corresponding to the narrow surface of the housing 21. The insulating film 22 can be a blue film. Of course, it can also be other films with insulating functions. As an example, see [reference needed]. Figure 4 and Figure 6 The insulating film 22 includes an adhesive layer 223 and an insulating layer 224. The adhesive layer 223 bonds the housing 21 and the insulating layer 224. The side of the insulating layer 224 away from the adhesive layer 223 is the outer surface of the insulating film 22. Figure 4 and Figure 6 The illustration shows a double-layer insulating film 22; however, a single-layer or multi-layer insulating film 22 may be used if necessary. For ease of explanation, Figure 4 and Figure 6 The cross-sectional diagram includes an additional section for structural adhesive 30.

[0057] In each battery cell 20, the second outer surface 222 of its respective insulating film 22 is bonded and fixed to the bottom wall 11 of the housing 10 by structural adhesive 30. That is, each battery cell 20 is bonded and fixed to the bottom wall 11 by the second outer surface 222 of its insulating film 22. In a plurality of battery cells 20, the first outer surfaces 221 of the insulating films 22 of adjacent battery cells 20 are bonded and fixed to the side wall 12 by structural adhesive 30. In a plurality of battery cells 20, the first outer surfaces 221 of the first and last battery cells 20 located along the first direction X near the side wall 12 are bonded and fixed to the side wall 12 by structural adhesive 30. The structural adhesive 30 can be, for example, epoxy resin, polyurethane, acrylic, etc.

[0058] Since the outer surface of the insulating film 22 is grid-like or striped, when the battery cell 20 is bonded to the housing 10 by the structural adhesive 30, and when the battery cells 20 are bonded to each other by the structural adhesive 30, the bonding surface area between the outer surface of the insulating film 22 and the structural adhesive 30 can be increased, the bonding strength can be improved, the risk of cracking between the structural adhesive 30 and the insulating film 22 can be reduced, and the firmness of the battery cell 20 can be improved.

[0059] Wherein, the bonding surface area between the first outer surface 221 and the structural adhesive 30 is S1, and the bonding surface area between the second outer surface 222 and the structural adhesive 30 is S2. Along the second direction Z, the height of the structural adhesive 30 above the second outer surface 222 is H. Along the third direction Y, the shear strength between the insulating film 22 and the structural adhesive 30 is σ. The first direction, the second direction, and the third direction are all perpendicular to each other. The third direction is the length direction of the battery cell 20, which satisfies: 800mm. 2 ≤S1≤3500mm 2 3000mm 2 ≤S2≤10000mm 2 , 3Mpa≤σ≤4.5Mpa, 2mm≤H≤5mm, 4.0*10 4 N·mm≤(S1+S2)*σ*H≤1.5*10 5 N·mm.

[0060] The bonding surface area S1 between the first outer surface 221 and the structural adhesive 30, and the bonding surface area S2 between the second outer surface 222 and the structural adhesive 30 are the outline area of ​​the insulating film 22, which can be obtained by multiplying the width of the insulating film by the length of the insulating film. Considering that the grid groove and stripe groove are relatively small and mainly serve to improve the roughness of the outer surface of the insulating film 22, the bonding surface area in the grid groove and stripe groove can be ignored in the calculation.

[0061] A force along the third direction Y is applied to the cell 20. There is a shear force between the first outer surface 221 of the insulating film 22 and the structural adhesive 30, and between the second outer surface 222 of the insulating film 22 and the structural adhesive 30. The shear strength is σ.

[0062] The shear strength σ can be measured using a universal testing machine. The method for measuring shear strength σ (GB / T 7124) is as follows: 1. Sample size: 100cm*25cm*2cm (Al 3003 specimen); 2. Adhesion area: 25cm*25cm; 3. Adhesion substrate: PET blue film or PC insulating sheet; 4. Repeatedly roll with a 2kg roller for more than 5 times, and let stand for 24 hours (at room temperature 23±2℃); 5. Tensile speed: 50mm / min.

[0063] When the above parameter requirements are met, the insulating film 22 and the structural adhesive 30 can be reliably bonded with a reasonable amount of adhesive, thereby achieving reliable fixation of the blade cell 20. At the same time, the overall weight of the battery pack 100 can be reduced, and costs can be lowered.

[0064] In some embodiments, refer to Figure 1 and Figure 2 Cell 20 is a blade cell, and along the first direction X, the width of cell 20 is W ( Figure 1As shown), 14.5mm≤W≤23mm; along the third direction Y, the length of cell 20 is L ( Figure 1 As shown), 350mm≤L≤550mm. Along the second direction Z, the height of cell 20 is H1, 85mm≤H1≤180mm.

[0065] H1 can be 85mm, 90mm, 95mm, 100mm, 130mm, 150mm, 180mm or any value between two of these.

[0066] W can be 14.5mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 23mm or any value between the two.

[0067] L can be 350mm, 400mm, 410mm, 450mm, 480mm, 500mm, 520mm, 550mm, or any value between the two.

[0068] Therefore, this method is applicable to blade batteries, solving the problem of battery cells easily falling off.

[0069] In some embodiments, refer to Figure 7 and Figure 8 Structural adhesive 30 completely covers the second outer surface 222.

[0070] Understandably, the second outer surface 222 corresponds to the side of the housing 21 closest to the bottom wall 11 along the second direction Z. The structural adhesive 30 between the insulating film 22 and the bottom wall 11 completely covers the second outer surface 222, so that the second outer surface 222 is fully bonded to the structural adhesive 30.

[0071] Therefore, for blade cells, the amount of structural adhesive used on the side closest to the bottom wall 11 is slightly larger to maximize the bonding strength and reduce the risk of cell 20 falling off.

[0072] In some embodiments, 1200mm 2 ≤S1≤3500mm 2 3000mm 2 ≤S2≤6500mm 2 5.0*10 4 N·mm≤(S1+S2)*σ*H≤1.5*10 5 N·mm.

[0073] Table 1 shows the first embodiment of this utility model ( Figures 1 to 8When the outer surface of the insulating film 22 is grid-like or striped, the adhesion failure of the insulating film (blue film) to the structural adhesive after vibration testing was tracked through different DOE tests. The vibration test standard is "Safety Requirements for Power Batteries for Electric Vehicles" (GB 38031-2020). The results are as follows:

[0074] Table 1

[0075]

[0076]

[0077] As can be seen from Table 1, all parameters in Examples 1-10 meet the above requirements, and no tearing failure problem occurred at the bonding point between the blue film and the structural adhesive in the simulation analysis and actual vibration test.

[0078] In both Comparative Example 1 and Comparative Example 2, (S1+S2)*σ*H is less than 5.0*10. 4 In Comparative Example 3, the amount of structural adhesive 30 was insufficient, resulting in tearing failure at the bonding interface between the blue film and the structural adhesive. In Comparative Example 4, H was greater than 5 mm, and (S1+S2)*σ*H was greater than 1.5*10. 5 Excessive application of adhesive (N·mm) will increase the weight and cost of the battery pack by 100.

[0079] Therefore, when the outer surface of the insulating film 22 is grid-like or striped and meets the above parameter requirements, the insulating film 22 and the structural adhesive 30 can be reliably bonded with a reasonable amount of adhesive, thereby achieving reliable fixation of the battery cell 20, while also reducing the overall weight of the battery pack and lowering costs.

[0080] In other embodiments, reference is made to Figures 9-11 The battery cell 20 is a square-shell battery cell, and the structural adhesive 30 partially covers the second outer surface 222; along the first direction X, the width of the battery cell 20 is W′, 25mm≤W′≤75mm; along the second direction Z, the height of the battery cell 20 is H2, 90mm≤H2≤130mm; along the third direction Y, the length of the battery cell 20 is L1, 150mm≤L1≤380mm, and the bonding length between the insulating film 22 and the structural adhesive 30 is L2, 130mm≤L2≤270mm.

[0081] W′ can be 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm or any value between the two.

[0082] H2 can be 90mm, 95mm, 100mm, 120mm, 130mm or any value between the two.

[0083] L1 can be 150mm, 200mm, 250mm, 270mm, 300mm, 350mm, 360mm, 380mm, or any value between two of these.

[0084] L2 can be 130mm, 140mm, 150mm, 200mm, 260mm, 270mm or any value between the two.

[0085] The structural adhesive 30 between the insulating film 22 and the bottom wall 11 partially covers the second outer surface 222, so that the second outer surface 222 is partially bonded to the structural adhesive 30.

[0086] Therefore, for square-shell battery cells, the amount of structural adhesive 30 used on the side closest to the bottom wall 11 is slightly less, which satisfies the bonding strength while reducing costs.

[0087] In some embodiments, 800mm 2 ≤S1≤1500mm 2 5000mm 2 ≤S2≤10000mm 2 2mm≤H≤4mm, 4.0*10 4 N·mm≤(S1+S2)*σ*H≤1.2*10 5 N·mm.

[0088] The methods for measuring shear strength σ and shear strength γ can refer to the first embodiment described above.

[0089] Table 2 shows the second embodiment of this utility model ( Figures 9-11 When the outer surface of the insulating film 22 is grid-like or striped, the adhesion failure of the insulating film (blue film) to the structural adhesive after vibration testing was tracked through different DOE tests. The vibration test standard is "Safety Requirements for Power Batteries for Electric Vehicles" (GB 38031-2020). The results are as follows:

[0090] Table 2

[0091]

[0092]

[0093] As can be seen from Table 2, all parameters in Examples 1-10 meet the above requirements, and no tearing failure problem occurred at the bonding point between the blue film and the structural adhesive in the simulation analysis and actual vibration test.

[0094] In both Comparative Example 1 and Comparative Example 2, (S1+S2)*σ*H is less than 4.0*10. 4 The amount of structural adhesive (N·mm) was insufficient, resulting in tearing failure at the bonding point between the blue film and the structural adhesive.

[0095] In Comparative Example 3, H is less than 2 mm, resulting in tearing failure at the bond between the blue film and the structural adhesive. In Comparative Example 4, (S1+S2)*σ*H is greater than 1.2*10. 5 Excessive application of adhesive (N·mm) will increase the weight and cost of the battery pack by 100.

[0096] In some embodiments, the thickness of the structural adhesive 30 is T2 ( Figure 8 As shown), 0.5mm≤T2≤2mm.

[0097] The thickness T2 of structural adhesive 30 is the minimum thickness of structural adhesive 30, ignoring the portion of structural adhesive 30 embedded in the grid or stripes. T2 can be 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.6mm, 1.7mm, 2mm, or any value between the two.

[0098] When T2 is greater than or equal to 0.5mm, the structural adhesive 30 has more sufficient contact with the outer surface of the insulating film 22, which can increase the contact area and improve the bonding strength. When T2 is less than or equal to 2mm, the amount of structural adhesive 30 can be used reasonably, so that the structural adhesive 30 is not too thick, reducing space occupation and increasing the volumetric energy density of the battery pack 100.

[0099] In some embodiments, the thickness of the insulating film 22 is T1 ( Figure 8 As shown), 0.1mm≤T1≤0.15mm.

[0100] T1 can be 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, or any value between two of these.

[0101] When T1 is greater than or equal to 0.1 mm, a grid or stripe structure can be easily formed on the outer surface of the insulating film 22, improving manufacturing efficiency and effectively protecting the battery cell 20; when T1 is less than or equal to 0.15 mm, the thickness of the insulating film 22 is not too large, reducing space occupation and increasing the volumetric energy density of the battery pack 100.

[0102] In some embodiments, the outer surface of the insulating film 22 is frosted.

[0103] Sandblasting can be used on PET / PP surfaces to increase surface roughness and create a frosted surface.

[0104] The frosted surface can further increase the bonding surface area between the insulating film 22 and the structural adhesive 30, thereby improving the bonding strength between the two.

[0105] In some embodiments, the roughness of the frosted surface is Ra, where 1 ≤ Ra ≤ 1.5. Ra can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, or any value between the two.

[0106] Roughness Ra Measurement Method: The Tokyo Seimitsu roughness tester uses the stylus method (probe method) for measurement. During measurement, the diamond stylus on the sensor maintains perpendicular contact with the surface being measured (the outer surface of the insulating film), and the sensor is dragged at a constant speed by a driver. The contour peaks and valleys of the surface being measured cause the stylus to move up and down. This displacement is synchronized with the magnetic core of the fulcrum, thereby changing the inductance of the differential inductor coil, and thus the roughness Ra is measured.

[0107] When Ra is greater than or equal to 1, the bonding surface area between the insulating film 22 and the structural adhesive 30 can be increased, thereby improving the bonding strength between the two. When Ra is less than or equal to 1.5, the thickness of PET / PP does not need to be too large to form a frosted surface, making the overall thickness of the insulating film 22 thinner, reducing space occupation, and increasing the volumetric energy density of the battery pack 100.

[0108] According to an embodiment of the present invention, in another aspect, an electrical device is provided, including the battery pack 100 mentioned above.

[0109] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, 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. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0110] A battery pack 100 is installed inside the vehicle, and the battery pack 100 can be located at the bottom, front, or rear of the vehicle. The battery pack 100 can be used to power the vehicle; for example, the battery pack 100 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 100 to supply power to the motor, for example, for the vehicle's starting, navigation, and operating power needs. In some embodiments of this application, the battery pack 100 can not only serve as the vehicle's operating power source but also as the vehicle's drive power source, replacing or partially replacing fuel or natural gas to provide driving force for the vehicle.

[0111] Unless otherwise stated, the values ​​of all parameters mentioned in this application can be determined using testing methods commonly used in the art. Unless otherwise stated, the test temperature for all parameters is 25°C.

[0112] Although embodiments of the present 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 present invention, and all such modifications and variations fall within the protection scope of this application.

Claims

1. A battery pack, characterized by, include: The enclosure includes a bottom wall and two side walls connected to opposite sides of the bottom wall along a first direction; Multiple battery cells are disposed in the housing and arranged along the first direction. Each battery cell includes a housing and an insulating film that wraps the housing. The outer surface of the insulating film is grid-like or striped. The insulating film includes a first outer surface and a second outer surface. The first outer surface corresponds to the surface with the largest area of ​​the housing. The first outer surfaces of two adjacent battery cells face each other along the first direction. The structural adhesive is used to bond and fix the second outer surface of each battery cell to the bottom wall, the first outer surface of the battery cell near the side wall to the side wall, and the first outer surfaces of two adjacent battery cells. Wherein, the bonding surface area between the first outer surface and the structural adhesive is S1, and the bonding surface area between the second outer surface and the structural adhesive is S2; along the second direction, the height of the structural adhesive above the second outer surface is H; along the third direction, the shear strength between the insulating film and the structural adhesive is σ, and the first direction, the second direction, and the third direction are mutually perpendicular, with the third direction being the length direction of the battery cell, satisfying: 800mm. 2 ≤S1≤3500mm 2 3000mm 2 ≤S2≤10000mm 2 , 3Mpa≤σ≤4.5Mpa, 2mm≤H≤5mm, 4.0*10 4 N·mm≤(S1+S2)*σ*H≤1.5*10 5 N·mm.

2. The battery pack according to claim 1, characterized in that, The battery cell is a blade battery cell, and along the first direction, the width of the battery cell is W, 14.5mm≤W≤23mm; Along the second direction, the height of the battery cell is H1, 85mm≤H1≤180mm; Along a third direction, the length of the battery cell is L, where 350mm ≤ L ≤ 550mm; The structural adhesive completely covers the second outer surface.

3. The battery pack according to claim 1, characterized in that, 1200mm 2 ≤S1≤3500mm 2 ,3000mm 2 ≤S2≤6500mm 2 ,5.0*10 4 N·mm≤(S1+S2)*σ*H≤1.5*10 5 N·mm。 4. The battery pack according to claim 1, characterized in that, The battery cell is a prismatic battery cell, and the structural adhesive partially covers the second outer surface; Along the third direction, the length of the battery cell is L1, 150mm≤L1≤380mm, and the bonding length between the insulating film and the structural adhesive is L2, 130mm≤L2≤270mm; Along the first direction, the width of the battery cell is W′, where 25mm≤W′≤75mm; Along the second direction, the height of the battery cell is H2, 90mm≤H2≤130mm.

5. The battery pack according to claim 4, characterized in that, 800mm 2 ≤S1≤1500mm 2 ,5000mm 2 ≤S2≤10000mm 2 ,2mm≤H≤4mm,4.0*10 4 N·mm≤(S1+S2)*σ*H≤1.2*10 5 N·mm。 6. The battery pack according to any one of claims 1-5, characterized in that, The thickness of the structural adhesive is T2, 0.5mm≤T2≤2mm; the thickness of the insulating film is T1, 0.1mm≤T1≤0.15mm.

7. The battery pack according to any one of claims 1-5, characterized in that, The outer surface of the insulating film is a frosted surface, and the roughness of the frosted surface is Ra, 1≤Ra≤1.

5.

8. The battery pack according to any one of claims 1-5, characterized in that, An opening is provided on one side of the housing; The cell also includes an electrode assembly and a cover plate, the cover plate closing the opening so that the cover plate and the housing together form a closed space for accommodating the electrode assembly.

9. The battery pack according to any one of claims 1-5, characterized in that, The insulating film includes an adhesive layer and an insulating layer. The adhesive layer is bonded between the housing and the insulating layer. Along the thickness direction of the insulating film, the side of the insulating layer facing away from the adhesive layer is the outer surface of the insulating film.

10. An electrical device, characterized by include: The battery pack as described in any one of claims 1-9.

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