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 casing, multiple battery cells, and structural adhesive. Each battery cell includes a shell and an insulating film. The insulating film is corrugated and includes a first outer surface and a second outer surface. 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. The shear strength between the insulating film and the structural adhesive is σ, the pull-out strength is γ, the height of the structural adhesive above the second outer surface is H, and the bonding length between the insulating film and the structural adhesive is L, satisfying: 1.5mm ≤ H ≤ 4mm, 600mm. 2 ≤S1≤2500mm 2 4000mm 2 ≤S2≤8000mm 2 With 3MPa≤σ≤4.5MPa and 3.5MPa≤γ≤5MPa, by using a reasonable amount of structural adhesive, the bonding strength can be ensured, the risk of battery cell detachment can be reduced, and the cost can also be reduced.

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 adhesive between the insulating film and the structural adhesive may fail, causing the cells to detach. Utility Model Content

[0004] In view of this, the present invention provides a battery pack and power supply device that, by using a reasonable amount of structural adhesive, ensures the bonding strength between the insulating film and the structural adhesive, reduces the risk of battery cell detachment, and also reduces 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 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; structural adhesive, between the second outer surface of each battery cell and the bottom wall, between the first outer surface of the battery cell near the side wall and the side wall, and... In two adjacent battery cells, the first outer surfaces are bonded and fixed together 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 shear strength between the insulating film and the structural adhesive is σ, and the pull-out strength is γ. Along the third direction, the bonding length between the insulating film and the structural adhesive is L. The first direction, the second direction, and the third direction are all perpendicular to each other. The second direction is the height direction of the battery cell, satisfying: 1.5mm ≤ H ≤ 4mm, 120mm ≤ L ≤ 430mm, 600mm 2 ≤S1≤2500mm 2 4000mm 2 ≤S2≤8000mm 2,3Mpa≤σ≤4.5Mpa, 3.5Mpa≤γ≤5Mpa,

[0006] Beneficial effects: When the insulating layer of the insulating film is wavy and meets the above parameter requirements, it can not only increase the bonding surface area between the insulating film and the structural adhesive and improve the bonding strength, but also control the reasonable amount of structural adhesive, reduce the overall weight of the battery pack and reduce costs.

[0007] In one optional embodiment, the battery cell is a blade battery cell, and along the first direction, the width of the battery cell is W1, 14.5mm≤W1≤23mm; along the second direction, the height of the battery cell is H1, 85mm≤H1≤180mm; the structural adhesive completely covers the second outer surface.

[0008] Beneficial effects: For blade cells, apply slightly more structural adhesive to the side closest to the bottom wall to maximize bonding strength and reduce the risk of blade cells falling off.

[0009] In one alternative implementation, 250mm ≤ L ≤ 430mm, 1000mm 2 ≤S1≤2500mm 2 4000mm 2 ≤S2≤6500mm 2 ,

[0010] Beneficial effects: Meeting the above parameters can improve the bonding strength of the blade battery cell and control the amount of structural adhesive used, thereby reducing costs.

[0011] In one optional embodiment, the battery cell is a prismatic cell, and along the first direction, the width of the battery cell is W2, 25mm≤W2≤65mm; along the second direction, the height of the battery cell is H2, 90mm≤H2≤130mm.

[0012] Beneficial effects: For prismatic cells within the aforementioned width and height range, the bonding strength of the prismatic cells can also be improved, and the amount of structural adhesive used can be controlled, thus reducing costs.

[0013] In one alternative implementation, 120mm≤L≤260mm, 1.5mm≤H≤3.5mm, 600mm 2 ≤S1≤1200mm 2 4000mm 2 ≤S2≤8000mm 2 ,

[0014] Beneficial effects: Meeting the above parameters can improve the bonding strength of the square-shell battery cells and control the amount of structural adhesive used, thereby reducing costs.

[0015] In one optional embodiment, along the third direction, the total length of the battery cell is L1, 150mm≤L1≤380mm; the structural adhesive portion covers the second outer surface.

[0016] Beneficial effects: For square-shell battery cells, the amount of structural adhesive used on the side closest to the bottom wall can be slightly reduced, which can meet the bonding strength requirements while also reducing weight and cost.

[0017] In one optional embodiment, the insulating film includes an adhesive layer and an insulating layer, the adhesive layer being adhered between the housing and the insulating layer, the insulating layer being wavy, the amplitude of the wavy shape being A, the spacing between two adjacent peaks being B, 120μm≤B≤200μm, 15μm≤A≤40μm.

[0018] Beneficial effects: When A is greater than or equal to 15μm, the larger wave amplitude increases the bonding surface area between the insulation layer and the structural adhesive and adhesive layer, thus improving bonding strength. When A is less than or equal to 40μm, the wave amplitude is not too large, allowing for a reduction in the thickness of the insulation film, reducing space occupation, and increasing the volumetric energy density of the battery pack. When B is greater than or equal to 120μm, the larger distance between the two peaks allows the structural adhesive to make more thorough contact with the insulation layer, improving bonding reliability. When B is less than or equal to 200μm, it increases the bonding surface area between the insulation layer and the structural adhesive and adhesive layer, thus improving bonding strength.

[0019] In one optional embodiment, the thickness of the structural adhesive is T2, where 0.5mm ≤ T2 ≤ 2mm.

[0020] 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 2, the amount of structural adhesive can be used reasonably, so that the structural adhesive is not too thick, reducing space occupation and improving the volumetric energy density of the battery pack.

[0021] In one optional embodiment, the thickness of the insulating film is T1, where 0.15mm ≤ T1 ≤ 0.2mm.

[0022] Beneficial effects: When T1 is greater than or equal to 0.15mm, 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 0.2mm, the thickness of the insulating film is not too large, reducing space occupation and increasing the volumetric energy density of the battery pack.

[0023] Secondly, this utility model also provides an electrical device, including: a battery pack as described in any of the above embodiments.

[0024] 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

[0025] 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.

[0026] Figure 1 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present utility model;

[0027] Figure 2 This is an exploded view of the battery cell according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of an insulating film according to an embodiment of the present utility model;

[0029] Figure 4 for Figure 3 A cross-sectional view cut along the CC axis;

[0030] Figure 5 for Figure 1 Cross-sectional view cut along EE;

[0031] Figure 6 for Figure 5 A magnified view of part D in the middle;

[0032] Figure 7 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 the purpose of illustration;

[0033] Figure 8 for Figure 7 A structural diagram from another perspective;

[0034] Figure 9 for Figure 8 A magnified view of part F in the middle.

[0035] Explanation of reference numerals in the attached figures:

[0036] 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

[0037] 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.

[0038] 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 adhesive to fail and cause the battery cell to fall off.

[0039] 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 the appropriate amount of structural adhesive, the bonding strength can be met while also reducing the overall weight of the battery pack and lowering costs.

[0040] The following is combined Figures 1 to 9 The following describes embodiments of the present invention.

[0041] 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 insulating film 22 is wavy and 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. Along the first direction X, the first outer surfaces 221 of the insulating films 22 of two adjacent battery cells 20 are disposed opposite 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 with 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 with structural adhesive 30.

[0042] 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.

[0043] 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.

[0044] 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 attached 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 9 The 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.

[0045] 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.

[0046] 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. Understandably, the insulating film 22 is attached to the outer side of the housing 21 by the adhesive layer 223 while covering the housing 21.

[0047] The insulating film includes an adhesive layer 223 and an insulating layer 224. The adhesive layer 223 is adhered between the housing 21 and the insulating layer 224, and the insulating layer 224 is wavy. The outer surface of the insulating layer 224 is the outer surface of the insulating film 22. The wavy shape of the insulating layer 224 means that both its outer and inner surfaces have a continuous uneven structure with crests and troughs. Along the thickness direction of the insulating film 22, the side of the insulating layer 224 away from the adhesive layer 223 is the outer surface, also called the outer surface of the insulating film 22, and this outer surface is adhered to the structural adhesive 30. The wavy shape can be sinusoidal, square, sawtooth, triangular, etc. Figure 3 The sinusoidal insulating layer 224 is shown. The shape of the insulating layer 224 in the prismatic battery cell can be referenced. Figure 3 .

[0048] 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 blade 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.

[0049] 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 multiple 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 multiple 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.

[0050] Because the insulating film 22 is wavy, when the battery cell 20 is pasted to the housing 10 with structural adhesive 30, and when the battery cells 20 are pasted together with structural adhesive 30, the bonding surface area between 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.

[0051] Wherein, the bonding surface area between the first outer surface 221 and the structural adhesive 30 is S1, the bonding surface area between the second outer surface 222 and the structural adhesive 30 is S2, along the second direction Z, the shear strength between the insulating film 22 and the structural adhesive 30 is σ, and the pull-out strength is γ, along the third direction Y, the bonding length between the insulating film 22 and the structural adhesive 30 is L, satisfying: 1.5mm≤H≤4mm, 120mm≤L≤430mm, 600mm 2 ≤S1≤2500mm 2 4000mm 2 ≤S2≤8000mm 2 ,3Mpa≤σ≤4.5Mpa, 3.5Mpa≤γ≤5Mpa,

[0052] The outline area corresponding to the adhesive surface area S1 is S1”. Adhesive surface area S1 = K * outline area S1”, where S1” = outline height * outline length. The outline height and length can be directly measured. K is a coefficient, determined using a 3D simulation model based on the ratio of the outer surface area of ​​the constructed insulating film to the outline area. This K value is then used to calculate the adhesive surface area S1. Here, K ranges from 1.3 to 1.6. The calculation of the adhesive surface area S2 can be performed with reference to S1. The K value can be 1.3, 1.4, 1.5, 1.6, or any value between these two ranges.

[0053] A force is applied to the cell 20 in the second direction Z away from the bottom wall 11. A shear force, σ, exists between the first outer surface 221 of the insulating film 22 and the structural adhesive 30. A pull-out force, γ, exists between the second outer surface 222 of the insulating film 22 and the structural adhesive 30. The shear strength σ and pull-out strength γ can be measured using a universal testing machine. The method for measuring the shear strength σ (GB / T 7124) is as follows: 1. Sample size: 100cm*25cm*2cm (Al 3003 sample); 2. Adhesion area: 25cm*25cm; 3. Adhesion substrate: PET blue film or PC insulating sheet; 4. Repeatedly roll with a 2kg roller at least 5 times, then let stand for 24 hours (at room temperature 23±2℃); 5. Tensile speed: 50mm / min.

[0054] The specific method for measuring shear strength γ (GB / T 6329) is as follows: 1. Sample size: square or round sample; 2. Adhesion area: 25cm*25cm; 3. Adhesion substrate: PET blue film or PC insulating sheet; 4. Roll repeatedly with a 2kg roller for more than 5 times, and let stand for 24 hours (at room temperature 23±2℃).

[0055] When the insulating film 22 is wavy and meets the above parameter requirements, it can not only increase the bonding surface area between the insulating film 22 and the structural adhesive 30 and improve the bonding strength, but also control the reasonable amount of structural adhesive, reduce the overall weight of the battery pack 100 and reduce costs.

[0056] In some embodiments, the battery cell 20 is a blade battery cell, and the structural adhesive 30 completely covers the second outer surface 222.

[0057] 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 entirely bonded to the structural adhesive 30. At this time, the length of the battery cell 20 is the bonding length between the structural adhesive 30 and the battery cell 20.

[0058] 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.

[0059] In some embodiments, refer to Figure 1 and Figure 2 Along the first direction X, the width of cell 20 is W1 ( Figure 1 As shown), 14.5mm≤W1≤23mm. Along the second direction Z, the height of cell 20 is H1, 85mm≤H1≤180mm.

[0060] W1 can be 14.5mm, 15.5mm, 16mm, 17mm, 18.5mm, 19.5mm, 20.5mm, 23mm or any value between the two.

[0061] H1 can be 85mm, 90mm, 95mm, 100mm, 150mm, 160mm, 180mm, or any value between two of these.

[0062] In some embodiments, 250mm≤L≤430mm, 1000mm 2 ≤S1≤2500mm 2 4000mm 2 ≤S2≤6500mm 2 ,

[0063] Table 1 shows the first embodiment of this utility model ( Figures 1 to 6 When the insulating film 22 is wavy, different DOE tests are used to track the adhesion failure of the insulating film (blue film) and structural adhesive after vibration testing. The vibration test standard is "Safety Requirements for Power Batteries for Electric Vehicles" (GB 38031-2020). The results are as follows:

[0064] Table 1

[0065]

[0066] 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 either simulation analysis or actual vibration testing. In Comparative Example 1... If the thickness is less than 5.5 N·mm, the amount of structural adhesive used is insufficient, leading to tearing failure at the bonding point between the blue film and the structural adhesive. In Comparative Example 2, H is less than 1.5 and S1 is less than 1000 mm. 2 The amount of structural adhesive used was insufficient, resulting in tearing and failure at the bonding point between the blue film and the structural adhesive. In Comparative Example 3, S1 was greater than 2500 mm. 2 , If the amount of adhesive applied exceeds 13 N·mm, it will increase the weight and cost of the battery pack by 100%.

[0067] Therefore, when the insulating layer 224 of the insulating film 22 is wavy 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.

[0068] In other embodiments, cell 20 is a prismatic cell, as shown in the reference. Figures 7-9 , refer to Figure 7 Along the third direction Y, the total length of the cell 20 is L1, 150mm≤L1≤380mm; the structural adhesive 30 partially covers the second outer surface 222.

[0069] L1 can be 150mm, 160mm, 170mm, 180mm, 200mm, 250mm, 300mm, 360mm, 380mm or any value between two of these.

[0070] 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.

[0071] 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.

[0072] In some embodiments, along the first direction X, the width of the cell 20 is W2, where 25mm ≤ W2 ≤ 65mm. Along the second direction Z, the height of the cell 20 is H2, where 90mm ≤ H2 ≤ 130mm.

[0073] W2 can be 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm or any value between the two.

[0074] H2 can be 90mm, 100mm, 105mm, 110mm, 120mm, 130mm or any value between the two.

[0075] In some embodiments, 120mm≤L≤260mm, 1.5mm≤H≤3.5mm, 600mm 2 ≤S1≤1200mm 2 4000mm 2 ≤S2≤8000mm 2 ,

[0076] The methods for measuring shear strength σ and shear strength γ can refer to the first embodiment described above.

[0077] Table 2 shows the second embodiment of this utility model ( Figures 7-9 When the insulating film 22 is wavy, different DOE tests are used to track the adhesion failure of the insulating film (blue film) and structural adhesive after vibration testing. The vibration test standard is "Safety Requirements for Power Batteries for Electric Vehicles" (GB 38031-2020). The results are as follows:

[0078] Table 2

[0079]

[0080] 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.

[0081] In Comparative Example 1, S2 is less than 4000 mm 2 , If the amount of structural adhesive is less than 2.4 N·mm, the required amount is insufficient, leading to tearing failure at the bonding point between the blue film and the structural adhesive. In Comparative Example 2, if H is less than 1.5, tearing failure also occurs at the bonding point between the blue film and the structural adhesive. In Comparative Example 3, if S1 is greater than 1200 mm... 2 , If the amount of adhesive applied exceeds 7.6 N·mm, it will increase the weight and cost of the battery pack by 100%.

[0082] In some embodiments, refer to Figure 4 The amplitude of the wave is A, the distance between two adjacent wave crests is B, 120μm≤B≤200μm, 15μm≤A≤40μm.

[0083] B can be 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm or any value between the two.

[0084] A can be 15μm, 18μm, 20μm, 25μm, 28μm, 30μm, 36μm, 38μm, 40μm or any value between the two.

[0085] Amplitude A is the vertical distance between the crest and the trough. Spacing B between two adjacent crests is the horizontal distance between two adjacent crests.

[0086] When A is greater than or equal to 15 μm, the wavy amplitude is larger, which increases the bonding surface area between the insulating layer 224 and the structural adhesive 30 and adhesive layer 223, thus improving the bonding strength. When A is less than or equal to 40 μm, the wavy amplitude is not too large, which reduces the thickness of the insulating film, reduces space occupation, and increases the volumetric energy density of the battery pack. When B is greater than or equal to 120 μm, the distance between the two peaks is larger, allowing the structural adhesive to make more sufficient contact with the insulating layer, thus improving the bonding reliability. When B is less than or equal to 200 μm, the distance between the two peaks is not too large, which increases the bonding surface area between the insulating layer and the structural adhesive and adhesive layer, thus improving the bonding strength.

[0087] In some embodiments, the thickness of the structural adhesive 30 is T2 ( Figure 6 and Figure 8 As shown), 0.5mm≤T2≤2mm.

[0088] 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.

[0089] When T2 is greater than or equal to 0.5, the structural adhesive 30 makes 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 0.5, 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.

[0090] In some embodiments, the thickness of the insulating film 22 is T1 ( Figure 8 As shown), 0.15mm≤T1≤0.2mm.

[0091] T1 can be 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, or any value between the two.

[0092] When T1 is greater than or equal to 0.15mm, a grid or striped 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 0.2mm, 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.

[0093] According to an embodiment of the present invention, in another aspect, an electrical device is provided, including the battery pack 100 mentioned above.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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 insulating film is wavy and 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. Along the first direction, the first outer surfaces of two adjacent battery cells face each other. 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 shear strength between the insulating film and the structural adhesive is σ, the pull-out strength is γ, and the height of the structural adhesive above the second outer surface is H; along the third direction, the bonding length between the insulating film and the structural adhesive is L, the first direction, the second direction, and the third direction are mutually perpendicular, the second direction is the height direction of the battery cell, satisfying: 1.5mm≤H≤4mm, 120mm≤L≤430mm, 600mm 2 ≤S1≤2500mm 2 4000mm 2 ≤S2≤8000mm 2 ,3Mpa≤σ≤4.5Mpa, 3.5Mpa≤γ≤5Mpa, 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 W1, 14.5mm≤W1≤23mm; Along the second direction, the height of the battery cell is H1, 85mm≤H1≤180mm; The structural adhesive completely covers the second outer surface.

3. The battery pack according to claim 2, characterized in that, 250mm≤L≤430mm,1000mm 2 ≤S1≤2500mm 2 ,4000mm 2 ≤S2≤6500mm 2 , 4. The battery pack according to claim 1, characterized in that, The battery cell is a square-shell battery cell, and along the first direction, the width of the battery cell is W2, 25mm≤W2≤65mm; 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, 120 mm < L < 260 mm, 1.5 mm < H < 3.5 mm, 600 mm 2 ≤ S1 < 1200 mm 2 , 4000 mm 2 ≤ S2 < 8000 mm 2 , 6. The battery pack according to claim 4, characterized in that, Along the third direction, the total length of the battery cell is L1, 150mm≤L1≤380mm; The structural adhesive partially covers the second outer surface.

7. The battery pack according to any one of claims 1-6, 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. The insulating layer is wavy. The waveform amplitude of the wavy insulating layer is A, and the distance between two adjacent peaks is B. 120μm≤B≤200μm, 15μm≤A≤40μm.

8. The battery pack according to any one of claims 1-6, characterized in that, The thickness of the insulating film is T1, where 0.15mm ≤ T1 ≤ 0.2mm; The thickness of the structural adhesive is T2, where 0.5mm ≤ T2 ≤ 2mm.

9. The battery pack according to any one of claims 1-6, 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.

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

Images