Battery pack and electric device

Abstract

This invention relates to the field of battery technology and discloses a battery pack and an electrical device. The battery pack includes: a housing; multiple battery cells 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 covering the outer surface of the cell shell; the surface of the insulating film facing the structural adhesive is wavy; the volume of the structural adhesive bonded to any battery cell is V, the bonding surface area of ​​the structural adhesive bonded to any battery cell is S, and the weight of any battery cell is M. The relationship between V, S, and M is 2.5 mm. 3 / g≤V / M≤7.5mm 3 / g, 3.25mm 2 / g≤S / M≤8mm 2 / g. By limiting reasonable V / M and S / M, sufficient adhesion between the structural adhesive and the insulating film can be ensured, reducing the possibility of separation or detachment of the structural adhesive and the insulating film during subsequent use of the battery pack.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a battery pack and an electrical device. 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. Summary of the Invention

[0006] In view of this, the present invention provides a battery pack and an electrical device 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] In a first aspect, the present invention provides a battery pack, comprising:

[0008] Box;

[0009] Multiple battery cells are bonded side-by-side inside the housing along the length or width direction of the housing using structural adhesive; each battery cell includes a battery cell housing and an insulating film wrapped around the outer surface of the battery cell housing; the surface of the insulating film facing the structural adhesive is wavy.

[0010] The volume of the structural adhesive bonded to any one of the battery cells is V, the bonding surface area of ​​the structural adhesive bonded to any one of the battery cells is S, and the weight of any one of the battery cells is M. The relationship between V, S, and M is: 2.5 mm³ / g ≤ V / M ≤ 7.5 mm³ / g, 3.25 mm 2 / g≤S / M≤8mm2 / g.

[0011] Beneficial Effects: This invention features a wavy surface on the side of the insulating film facing the structural adhesive, increasing the contact area between the insulating film and the structural adhesive, thus enhancing their adhesion. Arranging multiple cells side-by-side within the cavity allows for efficient use of the internal space of the housing, improving the overall energy density of the battery pack. Wrapping the outer surface of each cell housing with an insulating film prevents short circuits caused by direct contact between adjacent cell housings. Furthermore, by limiting the S / M ratio appropriately, it ensures that the structural adhesive provides sufficient adhesion to prevent cell loosening under vibration and impact conditions, while also avoiding excessive adhesion that leads to material waste or encroachment on cell arrangement space. By limiting the V / M ratio appropriately, it ensures that the thickness of the structural adhesive is sufficient to fill the gaps between the cell and the housing or between cells, achieving stable adhesion, while avoiding excessive adhesive application that increases the overall weight of the battery pack, affecting energy density, or hindering heat dissipation due to excessive adhesive layer thickness.

[0012] In one optional embodiment, 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, and 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.

[0013] Beneficial effects: Through the synergistic effect of the first and second structural adhesive layers, this invention can form a multi-dimensional fixed constraint on the battery cell, making the battery cell tightly bonded to the bottom of the casing, between adjacent battery cells, and between the battery cell and the inner side wall of the casing. This improves the overall structural strength and impact and vibration resistance of the battery pack, and effectively reduces the possibility of relative displacement and collision of the battery cells inside the battery pack under dynamic operating conditions.

[0014] In one optional embodiment, the battery cell is a blade battery cell, S = (2H + W0) × L × K, 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 2mm ≤ H ≤ 5mm; W0 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W0 is in the range of 14mm ≤ W0 ≤ 25mm; L is the length of the bonding portion of the first and second structural adhesive layers with the battery cell in the Y direction of the housing, and the value of L is in the range of 220mm ≤ L ≤ 400mm; K is the ratio of the surface area of ​​the insulating film facing the structural adhesive side to the contour area corresponding to the surface area, and the value of K is in the range of 1.3 ≤ K ≤ 1.6.

[0015] Beneficial effects: This invention quantifies the bonding surface area S of the structural adhesive through a clear formula, and combines the value ranges of H, W0 and L to adapt to the shape characteristics of the blade battery cell, ensuring a stable bonding of the battery cell.

[0016] In one optional embodiment, the battery cell is a blade battery cell, V = [W0 × T3 + 2 × (H + T3) × T2] × L, where T3 is the thickness of the first structural adhesive layer in the Z direction of the housing, 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 housing, and the value of T2 is: 0.5mm ≤ T2 ≤ 1.5mm; W0 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W0 is: 14mm ≤ W0 ≤ 25mm; H is the height of the second structural adhesive layer in the Z direction of the housing, and the value of H is: 2mm ≤ H ≤ 5mm; L is the length of the bonding portion of the first and second structural adhesive layers with the battery cell in the Y direction of the housing, and the value of L is: 220mm ≤ L ≤ 400mm.

[0017] Beneficial effects: By clarifying the calculation formula for the volume V of the structural adhesive and limiting T2, T3, W0, H and L to a reasonable range, this invention can quantify the amount of structural adhesive required for a single battery cell. This avoids both the problem of insufficient bonding strength caused by excessively thin structural adhesive and the problem of excessive space occupation and heat dissipation obstruction caused by excessively thick structural adhesive.

[0018] In one optional embodiment, the battery cell is a blade battery cell, L0 is the length of the bottom surface of the battery cell in the Y direction of the housing, and the value range of L0 is: 380mm≤L0≤600mm; H0 is the height of the battery cell in the Z direction of the housing, and the value range of H0 is: 85mm≤H0≤135mm.

[0019] Beneficial effects: By rationally setting the length L0 and height H0 of the blade battery cell, this invention facilitates the orderly arrangement of multiple blade battery cells within the housing, improving the space utilization of the housing. On the other hand, it provides dimensional basis for the application of structural adhesive and the calculation of bonding surface area and volume, ensuring that the amount of structural adhesive and bonding effect match the battery cell size.

[0020] In one alternative embodiment, the elastic modulus E of the structural adhesive after solidification is greater than 1700 MPa.

[0021] Beneficial effects: The elastic modulus E of the structural adhesive after solidification is greater than 1700 MPa, which means that it has high rigidity and can provide stable support for the battery cells. It can effectively resist external forces such as vibration and impact that the battery pack may be subjected to during use, reduce the risk of damage to the battery cells due to displacement or deformation, and ensure the structural stability and service life of the battery pack.

[0022] In one optional embodiment, the insulating film includes a substrate layer and an adhesive layer, the insulating film being adhered to the outside of the battery cell housing via the adhesive layer, and the structural adhesive being applied to the surface of the substrate layer away from the adhesive layer; the surface of the substrate layer facing the structural adhesive is bent into a wavy shape, and / or the surface of the substrate layer facing the adhesive layer is wavy.

[0023] Beneficial effects: The present invention sets the substrate layer in a wavy shape on one or both sides facing the structural adhesive, which can increase the effective bonding surface area of ​​the substrate layer for contact with the structural adhesive and / or adhesive layer, and increase the bonding strength.

[0024] In one optional embodiment, the amplitude of the wave on the surface of the insulating film is A, and the value of A is in the range of 25μm≤A≤40μm. The distance between two adjacent wave crests in the wave is B, and the value of B is in the range of 60μm≤B≤120μm.

[0025] Beneficial effects: By limiting A to between 15μm and 40μm and B to between 120μm and 200μm, this invention can increase the contact area and friction between the structural adhesive, the adhesive layer and the substrate layer, thereby improving the strength of the bond.

[0026] In one alternative embodiment, the insulating film has one or more of the following characteristics:

[0027] The tensile strength of the insulating film is greater than 150 MPa;

[0028] The elongation of the insulating film is not less than 50%;

[0029] The puncture strength of the insulating film is greater than 200 N / mm;

[0030] The thickness T1 of the insulating film is in the range of 0.15mm ≤ T1 ≤ 0.2mm.

[0031] Beneficial effects: By controlling the thickness of the insulating film within a suitable range, this invention ensures sufficient connection strength between the insulating film and the cell casing, preventing the insulating film from detaching from the cell casing. Furthermore, it prevents the insulating film from becoming too thick, occupying excessive space, and affecting the energy density of the battery pack. By controlling the tensile strength and / or elongation of the insulating film, the connection strength between the insulating film and the structural adhesive and / or adhesive layer can be further improved.

[0032] Secondly, the present invention also provides an electrical device, comprising: a battery pack as described above.

[0033] Beneficial effects: The electrical device of the present invention includes the battery pack as described above, and has all the beneficial technical effects of the battery pack, which will not be repeated here. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present invention;

[0037] Figure 3 for Figure 2 Side view of the battery pack shown;

[0038] Figure 4 for Figure 2 The diagram shows the structure of the battery pack after one side wall has been removed.

[0039] Figure 5 for Figure 1 A schematic diagram of the insulating film shown;

[0040] Figure 6 for Figure 5 The diagram shows the bonding between the insulating film and the structural adhesive.

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

[0042] 1. Housing; 2. Structural adhesive; 201. First structural adhesive layer; 202. Second structural adhesive layer; 3. Battery cell; 301. Insulating film; 3011. Substrate layer; 3012. Adhesive layer. Detailed Implementation

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

[0044] 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 invention provides a battery pack and an electrical device.

[0045] The following is combined Figures 1 to 6 The following describes embodiments of the present invention.

[0046] According to an embodiment of the present invention, in one aspect, such as Figures 1 to 4 As shown, a battery pack is provided, including: a housing 1 and multiple battery cells 3.

[0047] Specifically, multiple battery cells 3 are bonded side-by-side to the housing 1 along its length or width using structural adhesive 2. Each battery cell 3 includes a cell housing and an insulating film 301 wrapped around its outer surface. The insulating film 301 has a wavy surface facing the structural adhesive 2. The volume of the structural adhesive 2 bonded to any battery cell 3 is V, the bonding surface area of ​​the structural adhesive 2 bonded to any battery cell 3 is S, and the weight of any battery cell 3 is M. The relationship between V, S, and M is 2.5 mm. 3 / g≤V / M≤7.5mm 3 / g, 3.25mm 2 / g≤S / M≤8mm 2 / g.

[0048] In this embodiment of the invention, the surface of the insulating film 301 facing the structural adhesive 2 is wavy, which increases the contact area between the insulating film 301 and the structural adhesive 2, thereby improving their adhesion. This embodiment of the invention arranges multiple battery cells 3 side-by-side within the cavity, making efficient use of the internal space of the housing 1 and increasing the overall energy density of the battery pack. Wrapping the outer surface of each battery cell housing with the insulating film 301 prevents short circuits caused by direct contact between adjacent battery cell housings. Furthermore, by limiting the appropriate S / M ratio, it is possible not only to ensure that the structural adhesive 2 provides sufficient adhesion to prevent the battery cells 3 from loosening under vibration, impact, or other conditions, but also to avoid excessive adhesion leading to material waste or space constraints on the battery cell arrangement. By limiting the appropriate V / M ratio, it is possible to ensure that the thickness of the structural adhesive 2 is sufficient to fill the gaps between the battery cell 3 and the housing 1 or between the battery cells 3, achieving stable adhesion, while avoiding excessive adhesive layer that increases the overall weight of the battery pack, affecting energy density, or causing heat dissipation obstruction due to excessively thick adhesive layer 3012.

[0049] 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 cells in this embodiment of the invention can be lithium-ion cells, potassium-ion cells, sodium-ion cells, lithium-sulfur cells, etc., with lithium-ion cells being particularly preferred. During battery charging and discharging, 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.

[0050] It is understandable that the V / M ratio can be, but is not limited to, 2.5mm. 3 / g, 2.56mm 3 / g, 2.81mm 3 / g, 3mm 3 / g, 3.46mm 3 / g, 3.7mm 3 / g, 4mm 3 / g, 4.48mm 3 / g, 4.71mm 3 / g, 5mm 3 / g, 5.53mm 3 / g, 5.54mm 3 / g, 5.60mm 3 / g, 6mm 3 / g, 7mm 3 / g, 7.49mm 3 / g, 7.5mm³ / g. The S / M ratio can be, but is not limited to, 3.25mm³ / g. 2 / g, 3.35mm 2 / g, 3.77mm 2 / g, 4mm 2 / g, 4.08mm 2 / g, 4.24mm 2 / g, 4.46mm 2 / g, 4.49mm 2 / g, 4.88mm 2 / g, 5mm 2 / g, 5.05mm2 / g, 5.55mm 2 / g, 5.92mm 2 / g, 6.09mm 2 / g, 6.48mm 2 / g, 6.50mm 2 / g, 6.65mm 2 / g, 7mm 2 / g, 8mm 2 / g. Furthermore, in this embodiment, the value of M can range from 1500g to 2860g.

[0051] It should be noted that because the surface shape of the insulating film 301 facing the structural adhesive 2 is wavy, the surface area of ​​the insulating film 301 is larger than its outline area. Specifically, surface area = K * outline area, where the outline area is equal to the length L0 of the insulating film 301 multiplied by the width W0 of the insulating film 301. After the insulating film 301 wraps the battery cell 3, the length and width of the insulating film 301 located on a certain side of the battery cell 3 are equal to the length and width of that side of the battery cell 3. In other words, the length and width of the insulating film 301 can be directly measured. K is a coefficient, which is obtained by constructing the shape of the insulating film using a three-dimensional simulation model, calculating its outline area and adhesive surface area, and then dividing the adhesive surface area by the outline area. It can be understood that the value of K is affected by the wave amplitude of the insulating film surface and the distance between two adjacent wave peaks.

[0052] According to one embodiment of the present invention, such as Figure 3 and Figure 4 As shown, 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 plurality of 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. Through the synergistic effect of the first structural adhesive layer 201 and the second structural adhesive layer 202, this embodiment of the invention 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 sidewalls 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.

[0053] It should be noted that the dynamic operating conditions mentioned above refer to the non-static states experienced by the battery pack during use, transportation, or testing. Specifically, these include scenarios where the battery pack is subjected to mechanical vibration (such as the bumps when the vehicle is driving or the vibration when the equipment is running), mechanical impact (such as collisions during handling or 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.

[0054] According to one embodiment of the present invention, such as Figure 3 and Figure 4 As shown, cell 3 is a blade cell, S = (2H + W0) × L × K, 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 in the range of 2mm ≤ H ≤ 5mm; W0 is the width of the bottom surface of cell 3 in the X direction of the housing, and the value of W0 is in the range of 14mm ≤ W0 ≤ 25mm; 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 in the range of 220mm ≤ L ≤ 400mm; K is the ratio of the surface area of ​​the insulating film 301 facing the structural adhesive 2 to the contour area corresponding to the surface area, and the value of K is in the range of 1.3 ≤ K ≤ 1.6. This embodiment of the invention quantifies the bonding surface area S of the structural adhesive 2 through a clear formula, and, combined with the value ranges of H, W0, and L, can adapt to the shape characteristics of the blade cell, ensuring a stable bond to cell 3.

[0055] According to one embodiment of the present invention, such as Figure 3 and Figure 4 As shown, cell 3 is a blade cell, V = [W0 × 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 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 of T2 is: 0.5mm ≤ T2 ≤ 1.5mm; W0 is the width of the bottom surface of cell 3 in the X direction of the housing, and the value of W0 is: 14mm ≤ W0 ≤ 25mm; H is the height of the second structural adhesive layer 202 in the Z direction of the housing, and the value of H is: 2mm ≤ H ≤ 5mm; 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: 220mm ≤ L ≤ 400mm. By defining the calculation formula for the volume V of the structural adhesive 2 and limiting T2, T3, W0, H and L to a reasonable range, the amount of structural adhesive 2 required for a single battery cell 3 can be quantified. This avoids both the problem of insufficient bonding strength caused by the structural adhesive 2 being too thin and the problem of excessive space occupation and heat dissipation obstruction caused by the structural adhesive 2 being too thick.

[0056] It should be noted that in this embodiment, V refers to the volume of structural adhesive 2 located between the wave crests of the waves on the surface of the insulating film 301 and the cell casing after the structural adhesive 2 fills the wave troughs on the surface of the insulating film 301. The amount of structural adhesive 2 filling the wave troughs is negligible. During the battery pack assembly process, after the structural adhesive 2 comes into contact with the cell 3, it will deform under the pressure of the cell 3. Since the shape of the deformed structural adhesive 2 is irregular, to reduce calculation errors, T2, T3, H, and L in this embodiment are all average values. Furthermore, W0 is the distance between two opposite surfaces of the cell 3 in the X direction of the casing, and W0 is the width of the insulating film 302 located at the bottom surface of the cell in the X direction of the casing.

[0057] It is understood that, in the embodiments of the present invention, the value of W0 can be, but is not limited to, 14mm, 14.5mm, 15mm, 16mm, 16.2mm, 17mm, 18mm, 19mm, 20mm, 21mm, 21.8mm, 22mm, 23mm, 24mm, and 25mm. The value of T3 can be, but is not limited to, 0.5mm, 0.55mm, 0.6mm, 0.8mm, 1mm, 1.3mm, 1.5mm, 1.65mm, 1.8mm, and 2mm. The value of T2 can be, but is not limited to, 0.5mm, 0.55mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.3mm, 1.4mm, and 1.5mm. The value of H can be, but is not limited to, 2mm, 2.35mm, 3mm, 3.3mm, 3.5mm, 3.52mm, 4mm, 4.03mm, 4.1mm, 4.2mm, 4.3mm, and 5mm. The value of L can be, but is not limited to, 220mm, 245mm, 250mm, 255mm, 270mm, 275mm, 280mm, 295mm, 300mm, 310mm, 315mm, 330mm, 335mm, 350mm, 370mm, 375mm, 380mm, 390mm, and 400mm.

[0058] According to one embodiment of the present invention, such as Figure 3 and Figure 4As shown, cell 3 is a blade cell. L0 is the length of the bottom surface of cell 3 in the Y direction of the housing, and the value range of L0 is 380mm≤L0≤600mm; H0 is the height of cell 3 in the Z direction of the housing, and the value range of H0 is 85mm≤H0≤135mm. This embodiment of the invention, by reasonably setting the length L0 and height H0 of the blade cell, on the one hand, facilitates the orderly arrangement of multiple blade cells within the housing 1, improving the space utilization of the housing 1; on the other hand, it provides dimensional basis for the layout of structural adhesive 2 and the calculation of the bonding surface area and volume, ensuring that the amount of structural adhesive 2 and the bonding effect match the size of cell 3.

[0059] It is understood that, in the embodiments of the present invention, the value of L0 can be, but is not limited to, 380mm, 400mm, 420mm, 430mm, 440mm, 450mm, 460mm, 470mm, 500mm, 510mm, 530mm, 535mm, 540mm, 550mm, 570mm, 580mm, and 600mm. The value of H0 can be, but is not limited to, 85mm, 88mm, 90mm, 95mm, 100mm, 107mm, 110mm, 121mm, 130mm, and 135mm.

[0060] It should be noted that L0 is the distance between two opposite surfaces of the battery cell 3 in the Y direction of the housing, and L0 is the length of the insulating film 302 located on the bottom surface of the battery cell in the Y direction of the housing; H0 is the distance between two opposite surfaces of the battery cell 3 in the Z direction of the housing, and H0 is the height of the insulating film 302 located on the side surface of the battery cell in the Z direction of the housing.

[0061] According to one embodiment of the present invention, the elastic modulus E of the structural adhesive 2 after solidification is greater than 1700 MPa. It can be understood that the elastic modulus E of the structural adhesive 2 after solidification being greater than 1700 MPa means that it has high rigidity, can provide stable support for the battery cell 3, effectively resist external forces such as vibration and impact that the battery pack may be subjected to during use, reduce the risk of damage to the battery cell 3 due to displacement or deformation, and ensure the structural stability and service life of the battery pack.

[0062] According to one embodiment of the present invention, such as Figure 5 and Figure 6As shown, the insulating film 301 includes a substrate layer 3011 and an adhesive layer 3012. The insulating film 301 is adhered to the outside of the battery cell housing via the adhesive layer 3012. Structural adhesive 2 is coated on the surface of the substrate layer 3011 away from the adhesive layer 3012. The substrate layer 3011 is made of polyethylene terephthalate or polypropylene; the adhesive layer 3012 is made of acrylic adhesive. Since polyethylene terephthalate or polypropylene has good mechanical strength, insulation properties, and high-temperature resistance, this embodiment of the invention selects polyethylene terephthalate or polypropylene as the material of the substrate layer 3011. This ensures that the substrate layer 3011 has good strength, providing stable structural support for the adhesive layer 3012, and also allows the insulating film 301 to be well-suited to the working environment of the battery cell 3. Furthermore, the use of acrylic adhesive as the adhesive layer 3012 utilizes the excellent bonding properties of acrylic adhesive to ensure a stable connection between the insulating film 301 and the battery cell housing. This avoids direct contact between the cell casing and the casing of the adjacent cell 3, and ensures that the cell 3 maintains a stable position during the use of the battery pack.

[0063] Furthermore, such as Figure 5 and Figure 6 As shown, the surface of the substrate layer 3011 facing the structural adhesive 2 is wavy, and / or the surface of the substrate layer 3011 facing the adhesive layer 3012 is wavy. By making the side or both sides of the substrate layer 3011 facing the structural adhesive 2 wavy, this embodiment of the invention increases the effective bonding surface area of ​​the substrate layer 3011 for contact with the structural adhesive 2 and / or the adhesive layer 3012, thereby increasing the connection strength.

[0064] According to one embodiment of the present invention, such as Figure 5 and Figure 6 As shown, the bending amplitude of the wave on the surface of the insulating film 301 is A, and the value of A ranges from 15μm to 40μm. The distance between two adjacent wave crests is B, and the value of B ranges from 120μm to 200μm. In this embodiment of the invention, A is limited to between 15μm and 40μm, and B is limited to between 120μm and 200μm. This increases the contact area and friction between the structural adhesive 2, the adhesive layer 3012, and the substrate layer 3011, thereby improving the bonding strength.

[0065] It is understood that the value of A can be, but is not limited to, 15μm, 16μm, 18μm, 20μm, 25μm, 26μm, 27μm, 30μm, 32μm, 34μm, 36μm, 38μm, and 40μm. The value of B can be, but is not limited to, 120μm, 130μm, 150μm, 160μm, 166μm, 170μm, 174μm, 180μm, 182μm, 185μm, 190μm, 198μm, and 200μm.

[0066] According to one embodiment of the present invention, the insulating film 301 has one or more of the following characteristics: the tensile strength of the insulating film 301 is greater than 150 MPa; the elongation of the insulating film 301 is not less than 50%; the puncture strength of the insulating film 301 is greater than 200 N / mm; and the thickness T1 of the insulating film 301 is in the range of 0.15 mm ≤ T1 ≤ 0.2 mm. By controlling the thickness of the insulating film 301 within a suitable range, this embodiment of the present invention ensures sufficient connection strength between the insulating film 301 and the cell housing, preventing the insulating film 301 from detaching from the cell housing; it also prevents the insulating film 301 from being too thick, occupying too much space, and affecting the energy density of the battery pack. Furthermore, by controlling the tensile strength and / or elongation of the insulating film 301, the connection strength between the insulating film 301 and the structural adhesive 2 and / or adhesive layer 3012 can be further improved.

[0067] It should be noted that the thickness T1 of the insulating film 301 in this embodiment is the remaining thickness after removing the structural adhesive 2 (the amount of adhesive is small and can be ignored) that fills the trough of the wave.

[0068] According to an embodiment of the present invention, in another aspect, the present invention also provides an electrical device, including a battery pack as described above. The electrical device of the present invention includes the battery pack as described above, and possesses all the beneficial technical effects of the battery pack, which will not be repeated here.

[0069] It should be noted that 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.

[0070] Taking a vehicle as an example, the battery pack inside the vehicle can be located at the bottom, front, or rear of the vehicle. The battery pack can be used to power the vehicle, for example, as its operating power source. The vehicle may also include a controller and a motor. The controller controls the battery pack to supply power to the motor, for example, to meet the vehicle's power needs during starting, navigation, and driving. In some embodiments of this application, the battery pack can not only serve as the vehicle's operating power source but also as its driving power source, replacing or partially replacing fuel or natural gas to provide propulsion for the vehicle.

[0071] The technical effects of the present invention will be illustrated below with reference to specific embodiments and comparative examples.

[0072] 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).

[0073] Table 1

[0074]

[0075]

[0076] After simulation analysis and vibration testing, the insulating film 301 of the battery packs in Examples 1 to 10 did not show any tearing problems, and the insulating film 301 and structural adhesive 2 were not easily separated. However, in Comparative Examples 1 and 2, the insulating film 301 showed tearing problems after simulation analysis and vibration testing, and the insulating film 301 and structural adhesive 2 easily separated. The reason for this problem in Comparative Example 1 was that the V / M ratio was too small, resulting in insufficient bonding strength; the reason for this problem in Comparative Example 2 was that the S / M ratio was too small, resulting in insufficient bonding strength. In Comparative Examples 3 and 4, after simulation analysis and vibration testing, the insulating film 301 did not show any tearing problems, and the insulating film 301 and structural adhesive 2 were not easily separated. However, the larger V / M ratio in Comparative Example 3 led to excessive adhesive application, increasing cost; the larger S / M ratio in Comparative Example 4 also led to excessive adhesive application, increasing cost. It should be noted that the insulating film 301 wrapped by the battery cell 3 in the battery packs corresponding to the embodiments and comparative examples in the table above is the same, that is, the wave amplitude on the surface of the insulating film 301 facing the structural adhesive 2 and the spacing between two adjacent wave peaks are the same. Therefore, the value of K is the same in all embodiments and comparative examples. Specifically, the value of K in the table above is 1.3.

[0077] Although embodiments of the 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 invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery pack, characterized by, include: Box; Multiple battery cells are bonded side-by-side inside the housing along the X direction of the housing using structural adhesive; each battery cell includes a battery cell housing and an insulating film wrapped around the outer surface of the battery cell housing; the surface of the insulating film facing the structural adhesive is wavy. The volume of the structural adhesive bonded to any one of the battery cells is V, the bonding surface area of ​​the structural adhesive bonded to any one of the battery cells is S, and the weight of any one of the battery cells is M. The relationship between V, S, and M is: 2.5 mm. 3 / g≤V / M≤7.5mm 3 / g, 3.25mm 2 / g≤S / M≤8mm 2 / g.

2. The battery pack of claim 1, wherein, 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.

3. The battery pack of claim 2, wherein, The battery cell is a blade battery cell, S = (2H + W0) × L × K, 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 2mm ≤ H ≤ 5mm; W0 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W0 is in the range of 14mm ≤ W0 ≤ 25mm; L is the length of the bonding part between the first and second structural adhesive layers and the battery cell in the Y direction of the housing, and the value of L is in the range of 220mm ≤ L ≤ 400mm; K is the ratio of the surface area of ​​the insulating film facing the structural adhesive side to the contour area corresponding to the surface area, and the value of K is in the range of 1.3 ≤ K ≤ 1.

6.

4. The battery pack of claim 2, wherein, The battery cell is a blade battery cell, V = [W0 × T3 + 2 × (H + T3) × T2] × L, where T3 is the thickness of the first structural adhesive layer in the Z direction of the housing, 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 housing, and the value of T2 is: 0.5mm ≤ T2 ≤ 1.5mm; W0 is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W0 is: 14mm ≤ W0 ≤ 25mm; H is the height of the second structural adhesive layer in the Z direction of the housing, and the value of H is: 2mm ≤ H ≤ 5mm; L is the length of the bonding part of the first and second structural adhesive layers with the battery cell in the Y direction of the housing, and the value of L is: 220mm ≤ L ≤ 400mm.

5. The battery pack of any one of claims 1-4, wherein, The battery cell is a blade battery cell. L0 is the length of the bottom surface of the battery cell in the Y direction of the housing, and the value range of L0 is: 380mm≤L0≤600mm; H0 is the height of the battery cell in the Z direction of the housing, and the value range of H0 is: 85mm≤H0≤135mm.

6. The battery pack of any one of claims 1-4, wherein, The elastic modulus E of the structural adhesive after solidification is greater than 1700 MPa.

7. The battery pack of any one of claims 1-4, wherein, The insulating film includes a substrate layer and an adhesive layer. The insulating film is adhered to the outside of the battery cell housing through the adhesive layer. The structural adhesive is applied to the surface of the substrate layer away from the adhesive layer. The surface of the substrate layer facing the structural adhesive is bent into a wavy shape, and / or the surface of the substrate layer facing the adhesive layer is wavy.

8. The battery pack of claim 7, wherein, The bending amplitude of the wave on the surface of the insulating film is A, and the value of A is in the range of 15μm≤A≤40μm. The distance between two adjacent wave crests in the wave is B, and the value of B is in the range of 120μm≤B≤200μm.

9. The battery pack of any one of claims 1-4, wherein, The insulating film has one or more of the following characteristics: The tensile strength of the insulating film is greater than 150 MPa; The elongation of the insulating film is not less than 50%; The puncture strength of the insulating film is greater than 200 N / mm; The thickness T1 of the insulating film is in the range of 0.15mm ≤ T1 ≤ 0.2mm.

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

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