Battery pack

Abstract

This utility model relates to the field of battery technology and discloses a battery pack, including a housing; multiple battery cells, which are bonded side-by-side to the housing along the X direction of the housing using structural adhesive; each battery cell includes a cell shell and an insulating film wrapped around the outer surface of the cell shell; the adhesive force between the insulating film and the structural adhesive is F; a first structural adhesive layer is located between the bottom surface of the multiple battery cells and the bottom surface of the housing, and a second structural adhesive layer is located between two adjacent battery cells and between the battery cells at both ends and the corresponding inner sidewalls of the housing; the volume of the structural adhesive bonded to any battery cell is V, and the bonding area of ​​the structural adhesive bonded to any battery cell is S. The relationship between S, F, and V satisfies: 0.4N ≤ V×F / S ≤ 1.2N. Controlling the ratio of V×F / S within the range of 0.4N to 1.2N not only avoids material waste caused by excessive structural adhesive but also prevents insufficient adhesive strength caused by insufficient structural adhesive.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a battery pack. Background Technology

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

[0003] A battery pack typically consists of multiple battery cells, which are fixed inside the pack's casing. A battery cell generally includes a cover, casing, electrode assembly, electrode assembly end plates, bare cell insulating sheets, insulating film (such as blue film), and a cover plate top patch. The cover is welded to the casing and forms a sealed space protecting the electrode assembly. The bare cell insulating sheets cover the electrode assembly to protect it and prevent short circuits caused by contact between the electrode assembly and the casing. The electrode assembly end plates secure the tabs and provide space for their protection. The insulating film mainly covers the outside of the casing, providing external insulation.

[0004] In general, in order to securely assemble multiple cells inside the battery pack, structural adhesive is usually applied between two adjacent cells and between multiple cells and the inner wall of the battery pack, so as to bond and fix the cells inside the battery pack.

[0005] However, during the use of the battery pack, the bonding between the insulating film and the structural adhesive may fail due to insufficient adhesion, thus affecting the long-term reliability of the battery cells. Utility Model Content

[0006] In view of this, the present invention provides a battery pack to solve the problem of bonding failure of the insulating film and structural adhesive on the outside of conventional battery cells due to insufficient adhesion.

[0007] This utility model provides a battery pack, comprising:

[0008] Box;

[0009] Multiple battery cells are bonded side-by-side to the housing along the X direction of the housing using structural adhesive; each battery cell includes a cell housing and an insulating film wrapped around the outer surface of the cell housing; the adhesive force between the insulating film and the structural adhesive is F;

[0010] The structural adhesive includes a first structural adhesive layer and a second structural adhesive layer. The first structural adhesive layer is located between the bottom surface of the plurality of battery cells and the bottom surface of the housing. The second structural adhesive layer is located between two adjacent battery cells and between the battery cells at both ends and the corresponding inner sidewalls of the housing.

[0011] The volume of the structural adhesive bonded to any of the battery cells is V, and the bonding area of ​​the structural adhesive bonded to any of the battery cells is S. The relationship between S, F and V satisfies: 0.4N≤V×F / S≤1.2N.

[0012] Beneficial Effects: This invention controls the V×F / S ratio within the range of 0.4N to 1.2N, which not only avoids material waste and tight cell assembly space caused by excessive structural adhesive, but also prevents insufficient bonding strength due to insufficient structural adhesive. Thus, it ensures a stable fit between the cell and the housing while achieving efficient use of structural adhesive and rational cell assembly. Secondly, this invention arranges multiple cells side-by-side within the cavity, making rational use of the internal space of the housing and improving the overall energy density of the battery pack. Furthermore, through the synergistic effect of the first and second structural adhesive layers, this invention forms multi-dimensional fixed constraints on the cells, ensuring tight bonding between the cells and the bottom of the housing, between adjacent cells, and between the cells and the inner sidewall of the housing. This improves the overall structural strength and impact and vibration resistance of the battery pack, effectively reducing the possibility of relative displacement and collision of cells within the battery pack under dynamic operating conditions.

[0013] In one optional embodiment, the battery cell is a blade battery cell, where the value of F ranges from 0.4 N / mm ≤ F ≤ 0.8 N / mm, and S = (2H + W1) × L, where H is the height of the second structural adhesive layer in the Z direction of the housing, and the value of H ranges from 3 mm ≤ H ≤ 8 mm; W1 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W1 ranges from 14 mm ≤ W1 ≤ 25 mm; and L is the length of the bonding portion between the first and second structural adhesive layers and the battery cell in the Y direction of the housing, and the value of L ranges from 220 mm ≤ L ≤ 400 mm.

[0014] Beneficial effects: This invention controls the bonding force F between the insulating film and the structural adhesive to between 0.4 N / mm and 0.8 N / mm. This ensures sufficient connection strength between the two, effectively resisting external forces generated by the battery pack under dynamic operating conditions (such as vibration and impact), avoiding separation or detachment due to insufficient adhesion, and ensuring stable fixing and reliable insulation of the blade battery cell. It also avoids excessive adhesion force that would make separation difficult during subsequent maintenance or disassembly, balancing structural safety during use with ease of later operation. Furthermore, by quantifying the bonding area S of the structural adhesive using a clear formula, and combining the value ranges of H, W1, and L, it can adapt to the shape characteristics of the blade battery cell, ensuring a stable bond.

[0015] In one optional implementation, V = [W1×T3+2×(H+T3)×T2]×L, where T3 is the thickness of the first structural adhesive layer in the Z direction of the box, and the value of T3 is in the range of 0.5mm≤T3≤3mm; T2 is the thickness of the second structural adhesive layer in the X direction of the box, and the value of T2 is in the range of 0.5mm≤T2≤2mm.

[0016] Beneficial effects: By clarifying the calculation formula for the volume V of the structural adhesive and limiting T2 and T3 within a reasonable range, this utility model can quantify the amount of structural adhesive required for a single battery cell. In this way, it can avoid the problem of insufficient bonding strength caused by the structural adhesive being too thin, and also avoid the problem of excessive space occupation and heat dissipation obstruction caused by the structural adhesive being too thick.

[0017] In one optional embodiment, L1 is the length of the bottom surface of the battery cell in the Y direction of the housing, and the value range of L1 is: 380mm≤L1≤600mm; the relationship between L and L1 satisfies: 0.5≤L / L1≤0.66.

[0018] Beneficial effects: This utility model limits the ratio of L to L1 to between 0.5 and 0.66, which can ensure that the bonding length between the structural adhesive and the battery cell is sufficient to provide stable bonding force and ensure that the battery cell is not easily loosened under dynamic working conditions, while avoiding material waste or affecting the heat dissipation of the battery cell due to excessive bonding length.

[0019] In one optional implementation, H1 is the height of the battery cell in the Z direction of the housing, and the value range of H1 is: 85mm≤H1≤135mm; the relationship between H and H1 satisfies: 0.3≤10×H / H1≤0.75.

[0020] Beneficial effects: This utility model controls the ratio of 10×H to cell height H1 between 0.3 and 0.75, which can provide sufficient bonding contact area between adjacent cells and between cells and the inner side wall of the box to enhance the fixing effect, without encroaching on the internal space of the battery pack due to excessive width.

[0021] In one optional embodiment, the battery cell is a square battery cell, the value of F is in the range of 0.4N / mm≤F≤0.8N / mm, S=(2H+W1)×L, where H is the height of the second structural adhesive layer in the Z direction of the housing, and the value of H is in the range of 3mm≤H≤6mm; W1 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W1 is in the range of 25mm≤W1≤55mm; L is the length of the bonding part of the first structural adhesive layer and the second structural adhesive layer with the battery cell in the Y direction of the housing, and the value of L is in the range of 110mm≤L≤250mm; the relationship between S, F and V satisfies: 0.4N≤V×F / S≤0.9N.

[0022] Beneficial Effects: This invention controls the adhesive force F between the insulating film and the structural adhesive to between 0.4 N / mm and 0.8 N / mm. This ensures sufficient connection strength between the two, effectively resisting external forces generated by the battery pack under dynamic operating conditions (such as vibration and impact), avoiding separation or detachment due to insufficient adhesive force, and ensuring stable fixing and reliable insulation of the square battery cell. It also avoids excessive adhesive force that would make separation difficult during subsequent maintenance or disassembly, balancing structural safety during use with ease of later operation. Secondly, by quantifying the adhesive area S of the structural adhesive using a specific formula, and combining the value ranges of H, W1, and L, it can adapt to the shape characteristics of the square battery cell, ensuring a stable bond. Furthermore, this invention limits the V×F / S ratio to between 0.4 N and 0.9 N, which not only avoids material waste and tight cell assembly space due to excessive structural adhesive, but also prevents insufficient adhesive strength caused by insufficient structural adhesive.

[0023] In one optional implementation, V = [W1×T3+2×(H+T3)×T2]×L, where T3 is the thickness of the first structural adhesive layer in the Z direction of the box, and the value of T3 is in the range of 0.5mm≤T3≤2mm; T2 is the thickness of the second structural adhesive layer in the X direction of the box, and the value of T2 is in the range of 0.5mm≤T2≤1.5mm.

[0024] Beneficial effects: By clarifying the calculation formula for the volume V of the structural adhesive and limiting T2 and T3 within a reasonable range, this utility model can quantify the amount of structural adhesive required for a single battery cell. In this way, it can avoid the problem of insufficient bonding strength caused by the structural adhesive being too thin, and also avoid the problem of excessive space occupation and heat dissipation obstruction caused by the structural adhesive being too thick.

[0025] In one optional embodiment, L1 is the length of the bottom surface of the battery cell in the Y direction of the housing, and the value range of L1 is: 150mm≤L1≤300mm; the relationship between L and L1 satisfies: 0.5≤L / L1≤0.9.

[0026] Beneficial effects: This utility model limits the ratio of L to L1 to between 0.5 and 0.9, which can ensure that the bonding length between the structural adhesive and the battery cell is sufficient to provide stable bonding force and ensure that the battery cell is not easily loosened under dynamic working conditions, while avoiding material waste or affecting the heat dissipation of the battery cell due to excessive bonding length.

[0027] In one optional implementation, H1 is the height of the battery cell in the Z direction of the housing, and the value range of H1 is: 90mm≤H1≤130mm; the relationship between H and H1 satisfies: 0.3≤10×H / H1≤0.6.

[0028] Beneficial effects: This utility model controls the ratio of 10×H to cell height H1 between 0.3 and 0.6, which can provide sufficient bonding contact area between adjacent cells and between cells and the inner side wall of the box to enhance the fixing effect, without encroaching on the internal space of the battery pack due to excessive width.

[0029] In one alternative embodiment, the surface energy of the insulating film is from 35 mN / m to 55 mN / m, and the thickness T1 of the insulating film is from 0.1 mm to 0.15 mm.

[0030] Beneficial effects: By controlling the surface energy of the insulating film between 35mN / m and 55mN / m, this invention improves the interfacial wettability and bonding strength between the insulating film and the structural adhesive, reducing problems such as separation and detachment of the insulating film and structural adhesive due to insufficient adhesion during battery pack use, thus ensuring the stability of cell fixation. Secondly, by controlling the thickness of the insulating film between 0.1mm and 0.15mm, this invention avoids increasing the overall size of the battery pack and affecting its energy density while ensuring reliable insulation performance. Attached Figure Description

[0031] 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.

[0032] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present utility model;

[0033] Figure 2 for Figure 1 The exploded view of the battery cell shown.

[0034] Figure 3 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present utility model;

[0035] Figure 4 for Figure 3 The diagram shows the structure of the battery pack after one side wall has been removed.

[0036] Figure 5 for Figure 3 Side view of the battery pack shown;

[0037] Figure 6 This is a schematic diagram of the structure of another battery cell according to an embodiment of the present invention;

[0038] Figure 7 for Figure 6 The exploded view of the battery cell shown.

[0039] Figure 8 This is a schematic diagram of another battery pack according to an embodiment of the present invention;

[0040] Figure 9 for Figure 8 The diagram shows the structure of the battery pack after one side wall has been removed.

[0041] Figure 10 for Figure 8 Top view of the battery pack shown;

[0042] Figure 11 for Figure 10 The diagram shows the structure of the battery pack as viewed from the perspective of AA.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Housing; 2. Structural adhesive; 201. First structural adhesive layer; 202. Second structural adhesive layer; 3. Battery cell; 301. Battery cell housing; 302. Insulating film. Detailed Implementation

[0045] 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.

[0046] To address the problem of bonding failure between the insulating film and structural adhesive on the outside of conventional battery cells due to insufficient adhesion, this utility model provides a battery pack.

[0047] The following is combined with Figures 1 to 11 The following describes embodiments of the present invention.

[0048] According to embodiments of the present invention, such as Figures 2 to 5 , Figures 7 to 11 As shown, a battery pack is provided, including: a housing 1 and multiple battery cells 3.

[0049] Specifically, multiple battery cells 3 are bonded side-by-side to the inside of the housing 1 along the X direction of the housing 1 using structural adhesive 2. Each battery cell 3 includes a battery cell housing 301 and an insulating film 302 wrapped around the outer surface of the battery cell housing 301. The bonding force between the insulating film 302 and the structural adhesive 2 is F. The structural adhesive 2 includes a first structural adhesive layer 201 and a second structural adhesive layer 202. The first structural adhesive layer 201 is located between the bottom surface of the multiple battery cells 3 and the bottom surface of the housing 1. The second structural adhesive layer 202 is located between two adjacent battery cells 3 and between the battery cells 3 at both ends and the corresponding inner sidewalls of the housing 1. The volume of the structural adhesive 2 bonded to any battery cell 3 is V, and the bonding area of ​​the structural adhesive 2 bonded to any battery cell 3 is S. The relationship between S, F, and V satisfies: 0.4N ≤ V × F / S ≤ 1.2N.

[0050] It should be noted that, in this embodiment of the invention, the "battery pack" is formed by electrically connecting a certain number of battery cells 3 together and placing them in the housing 1 to protect the battery cells 3 from external impacts, heat, and vibrations. The battery pack contains two or more battery cells 3, the specific number depending on the application of the battery pack and the parameters of a single battery group. In this embodiment of the invention, "battery cell 3" refers to a single battery cell capable of independent charging and discharging. The components of the battery cell 3 may include a positive electrode, a negative electrode, a separator, an electrolyte, and a housing assembly for encapsulating the positive electrode, negative electrode, separator, and electrolyte. This embodiment of the invention does not impose any particular limitations on the type or shape of the battery cell 3; it can be a blade cell, a square cell, or other types of battery cells 3. The battery cell 3 in this embodiment of the invention can be a lithium-ion cell, a potassium-ion cell, a sodium-ion cell, a lithium-sulfur cell, etc., with lithium-ion cells being particularly preferred. During the charging and discharging process of the battery, active ions repeatedly insert and extract between the positive and negative electrode plates. The electrolyte plays a role in conducting ions between the positive and negative electrode plates.

[0051] This embodiment of the invention controls the V×F / S ratio within the range of 0.4N to 1.2N, which not only avoids material waste and tight assembly space for the battery cells 3 due to excessive structural adhesive 2, but also prevents insufficient bonding strength caused by insufficient structural adhesive 2. Thus, it ensures a stable fit between the battery cells 3 and the housing 1 while achieving efficient utilization of the structural adhesive 2 and rational assembly of the battery cells 3. Secondly, this embodiment of the invention arranges multiple battery cells 3 side-by-side within the cavity, which can rationally utilize the internal space of the housing 1 and improve the overall energy density of the battery pack. Furthermore, this embodiment of the invention, through the synergistic effect of the first structural adhesive layer 201 and the second structural adhesive layer 202, can form multi-dimensional fixed constraints on the battery cells 3, ensuring a tight bond between the battery cells 3 and the bottom of the housing 1, between adjacent battery cells 3, and between the battery cells 3 and the inner sidewall of the housing 1. This improves the overall structural strength and impact and vibration resistance of the battery pack, effectively reducing the possibility of relative displacement and collision of the battery cells 3 within the battery pack under dynamic operating conditions.

[0052] Specifically, the dynamic operating conditions mentioned above refer to the non-static states experienced by the battery pack during use, transportation, or testing. These include scenarios such as mechanical vibration (e.g., bumps when the vehicle is in motion, vibrations when the equipment is running), mechanical impact (e.g., collisions during handling, accidental drops), and dynamic stress generated by expansion and contraction during the charging and discharging of the battery cell 3. These states will subject the battery cell 3 to continuous or instantaneous forces, which may cause changes in its position or stress state.

[0053] Furthermore, it is understood that the ratio of V×F / S in this embodiment can be, but is not limited to, 0.4N, 0.41N, 0.42N, 0.43N, 0.44N, 0.45N, 0.46N, 0.47N, 0.48N, 0.49N, 0.5N, 0.51N, 0.52N, 0.53N, 0.54N, 0.55N, 0.56N, 0.57N, 0.58N, 0.59N, 0.6N, 0.61N, 0.62N, 0.63N, 0.64N, 0.65N, 0.66N, 0.67N, 0.68N, 0.69N, 0.7N, 0.71N, and 0.72N. , 0.73N, 0.74N, 0.75N, 0.76N, 0.77N, 0.78N, 0.79N, 0.8N, 0.81N, 0.82N, 0.83N, 0.84N, 0.85N, 0.86N, 0.87N, 0.88N, 0.89N, 0.9N, 0.91 N, 0.92N, 0.93N, 0.94N, 0.95N, 0.96N, 0.97N, 0.98N, 0.99N, 1N, 1.11N, 1.12N, 1.13N, 1.14N, 1.15N, 1.16N, 1.17N, 1.18N, 1.19N, 1.2N.

[0054] According to one embodiment of the present invention, such as Figure 1 and Figure 5 As shown, cell 3 is a blade cell. The value of F is 0.4 N / mm ≤ F ≤ 0.8 N / mm, and S = (2H + W1) × L. Where H is the height of the second structural adhesive layer 202 in the Z direction of the housing, and the value of H is 3 mm ≤ H ≤ 8 mm; W1 is the width of the bottom surface of cell 3 in the X direction of the housing, and the value of W1 is 14 mm ≤ W1 ≤ 25 mm; L is the length of the bonding part between the first structural adhesive layer 201 and the second structural adhesive layer 202 and cell 3 in the Y direction of the housing, and the value of L is 220 mm ≤ L ≤ 400 mm. This embodiment of the invention controls the bonding force F between the insulating film 302 and the structural adhesive 2 between 0.4 N / mm and 0.8 N / mm. This ensures sufficient connection strength between the two, effectively resisting external forces generated by the battery pack under dynamic operating conditions (such as vibration and impact), and avoiding separation or detachment due to insufficient bonding force, thus ensuring stable fixing and reliable insulation of the blade battery cell. It also avoids excessive bonding force that would make separation difficult during subsequent maintenance or disassembly, balancing structural safety during use with ease of later operation. Furthermore, by quantifying the bonding area S of the structural adhesive 2 using a specific formula, and combining the value ranges of H, W1, and L, it can adapt to the shape characteristics of the blade battery cell, ensuring a stable bond to the battery cell 3.

[0055] It should be noted that in this embodiment, the adhesive force F between the insulating film 302 and the structural adhesive 2 is equal to the peel force between them per unit width. W1 is the distance between two opposite surfaces of the blade cell in the X direction of the housing, and W1 is the width of the insulating film 302 located at the bottom surface of the blade cell in the X direction of the housing.

[0056] It is understood that, in this embodiment, the adhesive force F between the insulating film 102 and the structural adhesive 2 can be, but is not limited to, 0.4 N / mm, 0.41 N / mm, 0.42 N / mm, 0.45 N / mm, 0.47 N / mm, 0.5 N / mm, 0.55 N / mm, 0.6 N / mm, 0.65 N / mm, 0.68 N / mm, 0.7 N / mm, 0.75 N / mm, and 0.8 N / mm. The value of W1 can be, but is not limited to, 14 mm, 14.5 mm, 15 mm, 16 mm, 16.2 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 21.8 mm, 22 mm, 23 mm, 24 mm, and 25 mm. The value of H can be, but is not limited to, 3mm, 4mm, 4.2mm, 5mm, 5.1mm, 5.8mm, 6mm, 6.3mm, 6.6mm, 7mm, 7.5mm, and 8mm. The value of L can be, but is not limited to, 220mm, 245mm, 255mm, 270mm, 295mm, 300mm, 310mm, 335mm, 350mm, 370mm, 375mm, 380mm, 390mm, and 400mm.

[0057] Furthermore, such as Figure 1 , Figure 4 as well as Figure 5 As shown, V = [W1×T3+2×(H+T3)×T2]×L, where T3 is the thickness of the first structural adhesive layer 201 in the Z direction of the housing, and the value range of T3 is: 0.5mm≤T3≤3mm; T2 is the thickness of the second structural adhesive layer 202 in the X direction of the housing, and the value range of T2 is: 0.5mm≤T2≤2mm. This embodiment of the invention, by clarifying the calculation formula for the volume V of the structural adhesive 2 and limiting T2 and T3 to a reasonable range, can quantify the amount of structural adhesive 2 required for a single battery cell 3. This avoids both insufficient bonding strength caused by excessively thin structural adhesive 2 and excessive space occupation and heat dissipation obstruction caused by excessively thick structural adhesive 2.

[0058] Similarly, the value of T3 can be, but is not limited to, 0.5mm, 0.6mm, 0.8mm, 1mm, 1.3mm, 1.5mm, 1.8mm, 2mm, 2.3mm, 2.5mm, and 3mm. The value of T2 can be, but is not limited to, 0.5mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.3mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, and 2mm.

[0059] It should be noted that during the battery pack assembly process, after the structural adhesive 2 comes into contact with the battery cell 3, the structural adhesive 2 will deform under the pressure of the battery cell 3. Since the shape of the structural adhesive 2 after deformation is irregular, in order to reduce calculation errors, T2, T3, H and L in this embodiment are all average values.

[0060] According to one embodiment of the present invention, such as Figure 4 As shown, L1 is the length of the bottom surface of the battery cell 3 in the Y direction of the housing. The value range of L1 is: 380mm≤L1≤600mm; the relationship between L and L1 satisfies: 0.5≤L / L1≤0.66. In this embodiment of the invention, the ratio of L to L1 is limited to between 0.5 and 0.66, which ensures that the bonding length between the structural adhesive 2 and the battery cell 3 is sufficient to provide stable adhesion, ensuring that the battery cell 3 is not easily loosened under dynamic working conditions, while avoiding material waste or affecting the heat dissipation of the battery cell 3 due to excessive bonding length.

[0061] Similarly, in this embodiment, the value of L1 can be, but is not limited to, 380mm, 400mm, 420mm, 430mm, 440mm, 450mm, 460mm, 470mm, 500mm, 510mm, 530mm, 540mm, 550mm, 570mm, 580mm, and 600mm. The ratio of L / L1 can be, but is not limited to, 0.5, 0.51, 0.52, 0.53, 0.56, 0.58, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, and 0.66.

[0062] It should be noted that L1 is the distance between two opposite surfaces of the blade cell in the Y direction of the housing, and L1 is the length of the insulating film 302 located on the bottom surface of the blade cell in the Y direction of the housing.

[0063] According to one embodiment of the present invention, such as Figure 1 As shown, H1 is the height of cell 3 in the Z direction of the housing, and the value range of H1 is: 85mm≤H1≤135mm; the relationship between H and H1 satisfies: 0.3≤10×H / H1≤0.75. This embodiment of the invention controls the ratio of 10×H to the height H1 of cell 3 between 0.3 and 0.75, which provides sufficient bonding contact area between adjacent cells 3 and between cell 3 and the inner wall of housing 1 to enhance the fixing effect, while avoiding excessive width that would encroach on the internal space of the battery pack.

[0064] Similarly, in this embodiment, the value of H1 can be, but is not limited to, 85mm, 88mm, 90mm, 95mm, 100mm, 107mm, 110mm, 121mm, 130mm, and 135mm. The ratio of 10×H to H1 can be, but is not limited to, 0.3, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.46, 0.47, 0.48, 0.5, 0.55, 0.56, 0.57, 0.58, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.7, 0.71, 0.73, and 0.75.

[0065] It should be noted that H1 is the distance between two opposite surfaces of the blade cell in the Z direction of the housing, and H1 is the height of the insulating film 302 located on the side of the blade cell in the Z direction of the housing.

[0066] According to one embodiment of the present invention, such as Figure 6 and Figure 11 As shown, cell 3 is a square cell. The value of F is 0.4 N / mm ≤ F ≤ 0.8 N / mm, and S = (2H + W1) × L. Where H is the height of the second structural adhesive layer 202 in the Z direction of the housing, and the value of H is 3 mm ≤ H ≤ 6 mm; W1 is the width of the bottom surface of cell 3 in the X direction of the housing, and the value of W1 is 25 mm ≤ W1 ≤ 55 mm; L is the length of the bonding part between the first structural adhesive layer 201 and the second structural adhesive layer 202 and cell 3 in the Y direction of the housing, and the value of L is 110 mm ≤ L ≤ 250 mm; the relationship between S, F and V satisfies: 0.4 N ≤ V × F / S ≤ 0.9 N. This embodiment of the invention controls the bonding force F between the insulating film 302 and the structural adhesive 2 between 0.4 N / mm and 0.8 N / mm. This ensures sufficient connection strength between the two, effectively resisting external forces generated by the battery pack under dynamic operating conditions (such as vibration and impact), avoiding separation or detachment due to insufficient bonding force, and ensuring stable fixing and reliable insulation of the square battery cell. It also avoids excessive bonding force that would make separation difficult during subsequent maintenance or disassembly, balancing structural safety during use with ease of later operation. Secondly, by quantifying the bonding area S of the structural adhesive 2 using a specific formula, and combining the value ranges of H, W1, and L, it can adapt to the shape characteristics of the square battery cell, ensuring a stable bond. Furthermore, this embodiment of the invention limits the V×F / S ratio to between 0.4 N and 0.9 N, which not only avoids material waste and tight assembly space for the battery cell 3 due to excessive structural adhesive 2, but also prevents insufficient bonding strength due to insufficient structural adhesive 2.

[0067] It should be noted that in this embodiment, the adhesive force F between the insulating film 302 and the structural adhesive 2 is equal to the peel force between them per unit width. W1 is the distance between two opposite faces of the square battery cell in the X direction of the housing, and W1 is the width of the insulating film 302 located at the bottom surface of the square battery cell in the X direction of the housing.

[0068] It is understood that, in this embodiment, the adhesive force F between the insulating film 102 and the structural adhesive 2 can be, but is not limited to, 0.4 N / mm, 0.41 N / mm, 0.42 N / mm, 0.45 N / mm, 0.47 N / mm, 0.5 N / mm, 0.55 N / mm, 0.6 N / mm, 0.65 N / mm, 0.68 N / mm, 0.7 N / mm, 0.75 N / mm, and 0.8 N / mm. The value of W1 can be, but is not limited to, 25 mm, 28 mm, 30 mm, 33 mm, 35 mm, 40 mm, 45 mm, 50 mm, 52 mm, and 55 mm. The value of H can be, but is not limited to, 3 mm, 3.5 mm, 4 mm, 4.2 mm, 4.8 mm, 5 mm, 5.1 mm, 5.3 mm, 5.5 mm, 5.6 mm, 5.8 mm, and 6 mm. The value of L can be, but is not limited to, 110mm, 115mm, 120mm, 125mm, 130mm, 135mm, 140mm, 142mm, 145mm, 150mm, 155mm, 160mm, 165mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 225mm, 230mm, 240mm, and 250mm.

[0069] Furthermore, such as Figure 6 , Figure 9 as well as Figure 11 As shown, V = [W1×T3+2×(H+T3)×T2]×L, where T3 is the thickness of the first structural adhesive layer 201 in the Z direction of the housing, and the value range of T3 is: 0.5mm≤T3≤2mm; T2 is the thickness of the second structural adhesive layer 202 in the X direction of the housing, and the value range of T2 is: 0.5mm≤T2≤1.5mm. This embodiment of the invention, by clarifying the calculation formula for the volume V of the structural adhesive 2 and limiting T2 and T3 to a reasonable range, can quantify the amount of structural adhesive 2 required for a single battery cell 3. This avoids both insufficient bonding strength caused by an excessively thin structural adhesive 2 and excessive space occupation and heat dissipation obstruction caused by an excessively thick structural adhesive 2.

[0070] It is understood that in this embodiment, the value of T2 can be, but is not limited to, 0.5mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.3mm, 1.4mm, and 1.5mm. The value of T3 can be, but is not limited to, 0.5mm, 0.6mm, 0.8mm, 1mm, 1.3mm, 1.5mm, 1.6mm, 1.8mm, and 2mm.

[0071] It should be noted that during the battery pack assembly process, after the structural adhesive 2 comes into contact with the battery cell 3, the structural adhesive 2 will deform under the pressure of the battery cell 3. Since the shape of the structural adhesive 2 after deformation is irregular, in order to reduce calculation errors, T2, T3, H and L in this embodiment are all average values.

[0072] According to one embodiment of the present invention, such as Figure 9 As shown, L1 is the length of the bottom surface of the battery cell 3 in the Y direction of the housing. The value range of L1 is: 150mm≤L1≤300mm; the relationship between L and L1 satisfies: 0.5≤L / L1≤0.9. In this embodiment of the invention, the ratio of L to L1 is limited to between 0.5 and 0.9, which ensures that the bonding length between the structural adhesive 2 and the battery cell 3 is sufficient to provide stable adhesion, ensuring that the battery cell 3 is not easily loosened under dynamic working conditions, while avoiding material waste or affecting the heat dissipation of the battery cell 3 due to excessive bonding length.

[0073] It is understood that the ratio of L / L1 in this embodiment can be, but is not limited to, 0.5, 0.51, 0.52, 0.53, 0.56, 0.58, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.7, 0.71, 0.72, 0.73, 0.75, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, and 0.9. The value of L1 can be, but is not limited to, 150mm, 158mm, 165mm, 170mm, 185mm, 190mm, 200mm, 220mm, 250mm, 280mm, and 300mm.

[0074] It should be noted that L1 is the distance between two opposite faces of the square battery cell in the Y direction of the housing, and L1 is the length of the insulating film 302 located at the bottom of the square battery cell in the Y direction of the housing.

[0075] According to one embodiment of the present invention, such as Figure 6As shown, H1 is the height of cell 3 in the Z direction of the housing, and the value range of H1 is: 90mm≤H1≤130mm; the relationship between H and H1 satisfies: 0.3≤10×H / H1≤0.6. In this embodiment of the invention, the ratio of 10×H to the height H1 of cell 3 is controlled between 0.3 and 0.6, which can provide sufficient bonding contact area between adjacent cells 3 and between cell 3 and the inner sidewall of housing 1 to enhance the fixing effect, without compromising the internal space of the battery pack due to excessive width.

[0076] It is understood that in this embodiment, the ratio of 10×H to H1 can be, but is not limited to, 0.3, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.46, 0.47, 0.48, 0.5, 0.55, 0.56, 0.57, 0.58, and 0.6. The value of H1 can be, but is not limited to, 90mm, 92mm, 95mm, 100mm, 107mm, 110mm, 120mm, 121mm, 125mm, and 130mm.

[0077] It should be noted that H1 is the distance between two opposite faces of the square battery cell in the Z direction of the housing, and H1 is the height of the insulating film 302 located on the side of the square battery cell in the Z direction of the housing.

[0078] According to one embodiment of the present invention, the surface energy of the insulating film 302 is 35 mN / m to 55 mN / m, and the thickness T1 of the insulating film 302 is 0.1 mm to 0.15 mm. By controlling the surface energy of the insulating film 302 between 35 mN / m and 55 mN / m, this embodiment of the present invention improves its interfacial wettability and bonding strength with the structural adhesive 2, reducing problems such as separation and detachment of the insulating film 302 and the structural adhesive 2 due to insufficient adhesion during battery pack use, thus ensuring the stability of the cell 3 fixation. Secondly, by controlling the thickness of the insulating film 302 between 0.1 mm and 0.15 mm, this invention avoids increasing the overall complexity of the battery pack and affecting its energy density while ensuring reliable insulation performance.

[0079] According to one embodiment of this utility model, the insulating film 302 includes a substrate layer and an adhesive layer. The insulating film 302 is adhered to the outside of the cell housing 301 via the adhesive layer, and structural adhesive 2 is coated on the surface of the substrate layer away from the adhesive layer. The substrate layer is made of polyethylene terephthalate or polypropylene; the adhesive layer is made of acrylic adhesive. Since polyethylene terephthalate or polypropylene has good mechanical strength, insulation properties, and high-temperature resistance, this utility model selects polyethylene terephthalate or polypropylene as the material of the substrate layer. On the one hand, this ensures that the substrate layer has good strength, ensuring that it can provide stable structural support for the adhesive layer; on the other hand, it allows the insulating film 302 to be well adapted to the working environment of the cell 3. Using acrylic adhesive as the adhesive layer utilizes the excellent bonding properties of acrylic adhesive to ensure that the insulating film 302 can be firmly connected to the cell housing 301. This avoids direct contact between the cell housing 301 and the housing of adjacent cells 3, and ensures that the cells 3 maintain a stable position during the use of the battery pack.

[0080] The technical effects of this utility model will be illustrated below with reference to specific embodiments and comparative examples.

[0081] Table 1: Cell 3 in both the example battery pack and the comparative battery pack are blade cells, and the test standard is: "Safety Requirements for Power Batteries for Electric Vehicles" (GB 38031-2020).

[0082] Table 1

[0083]

[0084]

[0085] In the battery packs of Examples 1 to 10, after simulation analysis and vibration testing, no tearing problem was observed in the insulating film 302, and the insulating film 302 and structural adhesive 2 were not easily separated. In the battery packs of Comparative Examples 1 to 3, after simulation analysis and vibration testing, tearing problem occurred in the insulating film 302, and the insulating film 302 and structural adhesive 2 were easily separated. The reason for this problem in the battery pack of Comparative Example 1 was that the VF / S ratio was too small, resulting in insufficient bonding strength; the reason for this problem in the battery pack of Comparative Example 2 was that the 10*H / H1 ratio was too small, resulting in insufficient bonding strength; and the reason for this problem in the battery pack of Comparative Example 3 was that the L / L1 ratio was too small, resulting in insufficient bonding strength. In the battery packs of Comparative Examples 4 and 5, after simulation analysis and vibration testing, no tearing problem was observed in the insulating film 302, and the insulating film 302 and structural adhesive 2 were not easily separated. However, the larger 10*H / H1 ratio in the battery pack of Comparative Example 4 resulted in excessive adhesive application and increased costs; the larger L / L1 ratio in the battery pack of Comparative Example 5 also resulted in excessive adhesive application and increased costs.

[0086] Table 2: Cell 3 in both the example battery pack and the comparative battery pack are square cells, and the test standard is: "Safety Requirements for Power Batteries for Electric Vehicles" (GB 38031-2020).

[0087] Table 2

[0088]

[0089]

[0090] In the battery packs of Examples 11 to 20, no tearing occurred at the insulating film 302 after simulation analysis and vibration testing, and the insulating film 302 and structural adhesive 2 did not easily separate. In the battery packs of Comparative Examples 6 to 8, tearing occurred at the insulating film 302 after simulation analysis and vibration testing, and the insulating film 302 and structural adhesive 2 easily separated. The reason for this problem in Comparative Example 6 was insufficient bonding strength due to a low VF / S ratio; the reason for this problem in Comparative Example 7 was insufficient bonding strength due to a low 10*H / H1 ratio; and the reason for this problem in Comparative Example 8 was insufficient bonding strength due to a low L / L1 ratio. In the battery packs of Comparative Examples 9 and 10, no tearing occurred at the insulating film 302 after simulation analysis and vibration testing, and the insulating film 302 and structural adhesive 2 did not easily separate. However, the larger 10*H / H1 ratio in Comparative Example 9 battery pack resulted in excessive adhesive application and increased costs; the larger L / L1 ratio in Comparative Example 10 battery pack also resulted in excessive adhesive application and increased costs.

[0091] 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 such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery pack, characterized in that, include: Box; Multiple battery cells are bonded side-by-side to the housing along the X direction of the housing using structural adhesive; each battery cell includes a cell housing and an insulating film wrapped around the outer surface of the cell housing; the adhesive force between the insulating film and the structural adhesive is F; The structural adhesive includes a first structural adhesive layer and a second structural adhesive layer. The first structural adhesive layer is located between the bottom surface of the plurality of battery cells and the bottom surface of the housing. The second structural adhesive layer is located between two adjacent battery cells and between the battery cells at both ends and the corresponding inner sidewalls of the housing. The volume of the structural adhesive bonded to any of the battery cells is V, and the bonding area of ​​the structural adhesive bonded to any of the battery cells is S. The relationship between S, F and V satisfies: 0.4N≤V×F / S≤1.2N.

2. The battery pack according to claim 1, characterized in that, The battery cell is a blade battery cell. The value of F is in the range of 0.4 N / mm ≤ F ≤ 0.8 N / mm, and S = (2H + W1) × L, where H is the height of the second structural adhesive layer in the Z direction of the housing, and the value of H is in the range of 3 mm ≤ H ≤ 8 mm; W1 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W1 is in the range of 14 mm ≤ W1 ≤ 25 mm; L is the length of the bonding part between the first structural adhesive layer and the second structural adhesive layer and the battery cell in the Y direction of the housing, and the value of L is in the range of 220 mm ≤ L ≤ 400 mm.

3. The battery pack according to claim 2, characterized in that, V = [W1×T3+2×(H+T3)×T2]×L, where T3 is the thickness of the first structural adhesive layer in the Z direction of the box, and the value of T3 is 0.5mm≤T3≤3mm; T2 is the thickness of the second structural adhesive layer in the X direction of the box, and the value of T2 is 0.5mm≤T2≤2mm.

4. The battery pack according to claim 2, characterized in that, L1 is the length of the bottom surface of the battery cell in the Y direction of the housing. The value range of L1 is: 380mm≤L1≤600mm; the relationship between L and L1 satisfies: 0.5≤L / L1≤0.

66.

5. The battery pack according to claim 2, characterized in that, H1 is the height of the battery cell in the Z direction of the housing. The value range of H1 is: 85mm≤H1≤135mm. The relationship between H and H1 satisfies: 0.3≤10×H / H1≤0.

75.

6. The battery pack according to claim 1, characterized in that, The battery cell is a square battery cell. The value of F is in the range of 0.4N / mm≤F≤0.8N / mm, and S=(2H+W1)×L, where H is the height of the second structural adhesive layer in the Z direction of the housing, and the value of H is in the range of 3mm≤H≤6mm; W1 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W1 is in the range of 25mm≤W1≤55mm; L is the length of the bonding part between the first structural adhesive layer and the second structural adhesive layer and the battery cell in the Y direction of the housing, and the value of L is in the range of 110mm≤L≤250mm; the relationship between S, F and V satisfies: 0.4N≤V×F / S≤0.9N.

7. The battery pack according to claim 6, characterized in that, V = [W1×T3+2×(H+T3)×T2]×L, where T3 is the thickness of the first structural adhesive layer in the Z direction of the box, and the value of T3 is 0.5mm≤T3≤2mm; T2 is the thickness of the second structural adhesive layer in the X direction of the box, and the value of T2 is 0.5mm≤T2≤1.5mm.

8. The battery pack according to claim 6, characterized in that, L1 is the length of the bottom surface of the battery cell in the Y direction of the housing. The value range of L1 is: 150mm≤L1≤300mm; the relationship between L and L1 satisfies: 0.5≤L / L1≤0.

9.

9. The battery pack according to claim 6, characterized in that, H1 is the height of the battery cell in the Z direction of the housing. The value range of H1 is: 90mm≤H1≤130mm. The relationship between H and H1 satisfies: 0.3≤10×H / H1≤0.

6.

10. The battery pack according to any one of claims 1 to 9, characterized in that, The surface energy of the insulating film is 35 mN / m to 55 mN / m, and the thickness T1 of the insulating film is 0.1 mm to 0.15 mm.

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