Battery pack and electric device

Abstract

The utility model relates to battery technical field discloses battery pack and electric device. Battery pack includes: box, a plurality of electric core, through structural glue and side bond in the box, electric core includes electric core shell and the insulating film of wrapping electric core shell outer surface, the side surface of insulating film towards structural glue is undulate, along the Z direction of box, structural glue is located between the bottom surface of a plurality of electric core and the bottom surface of box, the bonding area of any electric core bottom surface and structural glue is S3, insulating film is equipped with opening, the area of opening is S2, part structural glue is bonded with electric core shell through opening, the bonding strength between structural glue and insulating film is gamma, the bonding strength between structural glue and electric core shell is beta, S3, S2, gamma, beta between satisfy: 1.7*10 4 N≤(S3-S2)*gamma+S2*beta≤5.0*10 4 N. Through reasonable limitation related parameter, can effectively promote the bonding force between insulating film and structural glue.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, 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. Utility Model Content

[0006] In view of this, the present invention provides a battery pack and power supply 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, this utility model provides a battery pack, comprising:

[0008] Box;

[0009] 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.

[0010] Along the Z-direction of the housing, the structural adhesive is located between the bottom surfaces of the plurality of battery cells and the bottom surface of the housing; the bonding surface area between the bottom surface of any battery cell and the structural adhesive is S3; the insulating film located on the bottom surface of the battery cell has an opening, the area of ​​which is S2; a portion of the structural adhesive is bonded to the battery cell housing through the opening;

[0011] The bonding strength between the structural adhesive and the insulating film is γ, and the bonding strength between the structural adhesive and the battery cell casing is β; S3, S2, γ, and β satisfy the following relationship: 1.7 × 10⁻⁶. 4 N≤(S3-S2)×γ+S2×β≤5.0×10 4 N.

[0012] 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. By creating openings in the insulating film, this invention allows some of the structural adhesive to directly bond to the cell casing through these openings, providing a double layer of protection for the connection between the structural adhesive and the cell. Specifically, the structural adhesive not only bonds indirectly to the cell through the insulating film but also directly to the cell casing via the openings. This combination of two bonding methods significantly improves the overall reliability of the connection between the structural adhesive and the cell. Furthermore, the range defined by (S3-S2)×γ+S2×β ensures that when the entire battery pack is subjected to external forces such as vibration and impact, each part of the structural adhesive provides sufficient adhesive strength, allowing the cells to be securely installed within the casing. This reduces relative displacement between cells and between the cells and the casing, thereby lowering the risk of internal structural damage caused by cell movement and improving the overall safety and lifespan of the battery pack. Furthermore, this design, by rationally allocating the bonding surface area of ​​different structural adhesive layers and utilizing the bonding strength characteristics between different materials, can optimize the amount of structural adhesive used while ensuring connection strength, avoiding unnecessary material waste, and achieving a balance between performance and cost.

[0013] In one optional embodiment, the battery cell is a blade battery cell, S3 = W1 × L1 × K - S2 × (K - 1), where W1 is the width of the bonding portion between the structural adhesive and the battery cell in the X direction of the housing; L1 is the length of the bonding portion between the structural adhesive and the battery cell in the Y direction of the housing, and the value range of L1 is: 350mm ≤ L1 ≤ 470mm; K is the ratio of the surface area of ​​the insulating film facing the structural adhesive to the contour area corresponding to that surface area, and the value range of K is: 1.3 ≤ K ≤ 1.6.

[0014] Beneficial Effects: For blade-shaped battery cells, this invention quantifies the bonding area between the structural adhesive and the battery cell by clearly defining the specific calculation method for S3. This provides a basis for the rational placement and dosage control of the structural adhesive, ensuring that the bonding of the structural adhesive at different parts of the battery cell better conforms to the cell's shape characteristics. Furthermore, by limiting the specific value ranges of W1 and L1, the calculation of the bonding area can be made more closely aligned with the actual size characteristics of the blade-shaped battery cell. This ensures sufficient bonding surface area between the structural adhesive layer and the battery cell to provide stable adhesion, preventing the battery cell from being poorly fixed due to insufficient area. It also prevents excessive bonding area from leading to excessive structural adhesive usage, increasing the weight and cost of the battery pack. Simultaneously, standardized dimensional parameters help improve the consistency of battery pack assembly and production efficiency, further optimizing the overall performance of the battery pack.

[0015] In one optional embodiment, the opening includes a plurality of square holes spaced apart along the Y direction of the housing, the length direction of the square holes being consistent with the Y direction of the housing; S2 = n × W2 × L2, where n is the number of square holes and is a positive integer greater than or equal to 1, W2 is the width of the square holes, and the value range of W2 is: 8mm ≤ W2 ≤ 18mm; L2 is the length of the square holes, and the value range of L2 is: 20mm ≤ L2 ≤ 35mm.

[0016] Beneficial effects: Setting the openings to square holes, compared to other shapes such as round holes, increases the opening ratio (i.e., the ratio of S2 to S1), increasing the bonding surface area between the structural adhesive and the cell casing, and improving adhesion. Furthermore, the bonding surface area S2 between the structural adhesive and the cell casing is determined by the number of square holes n and the length L2 and width W2 of the square holes. Controlling L2 and W2 within a suitable range means controlling S2 within a suitable range. If S2 is too small, the bonding surface area between the cell casing and the structural adhesive is small. If S2 is too large, it means that the insulation effect of the insulating film on the cell casing will be poor, easily leading to insulation failure. At the same time, the manufacturing process of the insulating film will also become more difficult, easily resulting in dimensional deviations and making it difficult to guarantee yield.

[0017] In one optional embodiment, the area corresponding to the insulating film at the bottom surface of any of the battery cells is S1, S1 = W × L × K, where W is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W is in the range of 15mm ≤ W ≤ 28mm; L is the width of the bottom surface of the battery cell in the Y direction of the housing, and the value of L is in the range of 380 ≤ L ≤ 550mm; the relationship between W, W1, and W2 satisfies W2 < W1 < W; the relationship between S1 and S2 satisfies 18.75% ≤ S2 / S1 ≤ 34.62%.

[0018] Beneficial effects: In the X direction of the housing, a width range of 15mm ≤ W ≤ 28mm ensures sufficient volume for the cells to store energy while avoiding uneven distribution of structural adhesive on the bottom surface of the cells due to excessive width, which would affect the bonding effect. The W2 < W1 < W relationship ensures that the opening diameter W2 is smaller than the relevant dimension W1 of the insulating film, and W1 is smaller than the cell width W. This hierarchical relationship results in a reasonable distribution of the bonding area between the structural adhesive and the insulating film and cell shell, effectively dispersing stress and improving the overall connection strength. In the Y direction of the housing, a width range of 380 ≤ L ≤ 550mm satisfies the energy density requirements of the battery pack and provides the cells with suitable dimensions in the Y direction of the housing, facilitating the side-by-side arrangement of multiple cells along the X direction. In addition, this dimensional design optimizes the internal space utilization of the battery pack, reduces unnecessary volume waste, helps improve the overall energy density and heat dissipation performance of the battery pack, and extends the service life of the battery pack. This invention balances the bonding surface area between the structural adhesive and the insulating film, as well as between the structural adhesive and the battery cell casing, by controlling the S2 / S1 value within a suitable range. If the S2 / S1 value is too large, it means the opening area is too large, increasing the risk of insulation failure. If the S2 / S1 value is too small, it means the bonding surface area between the battery cell casing and the structural adhesive is too small, making it difficult to effectively improve the bonding strength between the two.

[0019] In one optional embodiment, along the Z direction of the housing, there is a gap between the opposite sides of the opening and the corresponding edge of the structural adhesive, and the relationship between W1 and W2 satisfies: 1.5mm≤(W1-W2) / 2≤3mm.

[0020] Beneficial effects: By limiting the gap between the opening and the corresponding edge of the structural adhesive on both sides, and specifying the relationship of 1.5mm≤(W1-W2) / 2≤3mm, this utility model can not only avoid the bonding surface area between the structural adhesive and the insulating film being too small due to the distance between the opening and the edge of the structural adhesive being too close, but also prevent the excessive amount of structural adhesive from being used due to the excessive gap, which would affect production costs and assembly space.

[0021] In one optional embodiment, along the X direction of the housing, the distance between the opposite two sides of the square hole and the corresponding edge of the battery cell housing is A, and the value of A is in the range of 3.5mm≤A≤6.5mm; along the Y direction of the housing, the interval between two adjacent square holes is B, and the value of B is in the range of B≥8mm.

[0022] Beneficial effects: By limiting the distance A between the opposite sides of the square holes and the corresponding edges of the battery cell housing along the X direction of the enclosure to 3.5mm to 6.5mm, sufficient insulation protection space is reserved for the edges of the battery cell housing, avoiding safety hazards caused by insufficient insulation film coverage due to excessively small distances, and preventing waste of effective bonding surface area on the bottom of the battery cell due to excessively large distances. Setting the interval B between adjacent square holes to ≥8mm along the Y direction of the enclosure ensures that the structural adhesive at each opening is relatively independent, reducing mutual interference and making the bonding of the structural adhesive to the battery cell housing through each square hole more uniform and reliable.

[0023] In one alternative implementation, 4.5 MPa ≤ β ≤ 7 MPa.

[0024] Beneficial effects: The range of 4.5Mpa≤β≤7Mpa ensures that the shear strength of the bond between the structural adhesive and the insulating film is at a reasonable level, so that the bonding of the insulating film in the (S1-S2) section can provide stable shear force.

[0025] In one alternative implementation, 3.5 MPa ≤ γ ≤ 5 MPa.

[0026] Beneficial effects: The setting of 3.5Mpa≤γ≤5Mpa enhances the shear strength of the structural adhesive directly bonding to the cell housing through the opening, making the direct bonding contribution of the S2 part more reliable.

[0027] In one optional embodiment, the amplitude of the wave on the surface of the insulating film (301) is C, and the value of C is in the range of 15μm≤C≤40μm. The distance between two adjacent wave crests in the wave is D, and the value of D is in the range of 120μm≤D≤200μm.

[0028] Beneficial effects: By limiting C to between 15μm and 40μm and D to between 120μm and 200μm, this invention can increase the contact area and friction between the structural adhesive and the insulating film, thereby improving the bonding strength.

[0029] Secondly, this utility model also provides an electrical device, including: a battery pack as described above.

[0030] Beneficial effects: The electrical device of this utility model 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

[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 A schematic diagram of the battery cell from another perspective;

[0034] Figure 3 for Figure 1 A schematic diagram of the insulating film shown;

[0035] Figure 4 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present utility model;

[0036] Figure 5 This is a schematic diagram of the structure of a battery pack after removing one side wall, according to another embodiment of the present utility model.

[0037] Figure 6 for Figure 5 The battery pack shown is a side view.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. Housing; 2. Structural adhesive; 3. Battery cell; 301. Insulating film; 3011. Opening. Detailed Implementation

[0040] 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.

[0041] 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 and power supply device.

[0042] The following is combined Figures 1 to 6 The following describes embodiments of the present invention.

[0043] According to embodiments of the present invention, on the one hand, such as Figures 1 to 6 As shown, a battery pack is provided, including: a housing 1 and multiple battery cells 3.

[0044] Specifically, multiple battery cells 3 are bonded side-by-side to the housing 1 along the X direction of the housing 1 using structural adhesive 2. Each battery cell 3 includes a battery cell shell and an insulating film 301 wrapped around the outer surface of the battery cell shell. The surface of the insulating film 301 facing the structural adhesive 2 is wavy. Along the Z direction of the housing 1, the structural adhesive 2 is located between the bottom surfaces of the multiple battery cells 3 and the bottom surface of the housing 1. The bonding surface area between the bottom surface of any battery cell 3 and the structural adhesive 2 is S3. The insulating film 301 on the bottom surface of the battery cell 3 has an opening 3011, the area of ​​which is S2. Part of the structural adhesive 2 is bonded to the battery cell shell through the opening 3011. The bonding strength between the structural adhesive 2 and the insulating film 301 is γ, and the bonding strength between the structural adhesive 2 and the battery cell shell is β. S3, S2, γ, and β satisfy the following condition: 1.7 × 10⁻⁶. 4 N≤(S3-S2)×γ+S2×β≤5.0×10 4 N.

[0045] 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 the adhesion between them. By creating a hole 3011 in the insulating film 301, this embodiment allows a portion of the structural adhesive 2 to be directly bonded to the battery cell housing through the hole 3011. This provides a double layer of protection for the connection between the structural adhesive 2 and the battery cell 3. Specifically, the structural adhesive 2 is not only indirectly bonded to the battery cell 3 through the insulating film 301, but also directly bonded to the battery cell housing through the hole 3011. This combination of two bonding methods significantly improves the overall reliability of the connection between the structural adhesive 2 and the battery cell 3. The range defined by (S3-S2)×γ+S2×β ensures that the structural adhesive 2 provides sufficient bonding strength for each part of the battery pack when subjected to external forces such as vibration and impact. This allows the battery cells 3 to be securely installed within the housing 1, reducing relative displacement between the battery cells 3 and between the battery cells 3 and the housing 1. This reduces the risk of internal structural damage caused by cell 3 movement, improving the overall safety and lifespan of the battery pack. Furthermore, this design, by rationally allocating the bonding surface area of ​​different structural adhesive 2 layers and utilizing the bonding strength characteristics between different materials, optimizes the amount of structural adhesive 2 used while ensuring connection strength, avoiding unnecessary material waste and achieving a balance between performance and cost.

[0046] 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 battery cell, a square battery cell, or other types of battery cells 3. The battery cell 3 in this embodiment of the invention can be a lithium-ion battery cell, a potassium-ion battery cell, a sodium-ion battery cell, a lithium-sulfur battery cell, etc., with lithium-ion batteries 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 acts as a conductor of ions between the positive and negative electrode plates. Furthermore, in this embodiment, the X direction of the housing is the width direction of housing 1, and the Z direction is the height direction of housing 1.

[0047] Furthermore, to ensure that the structural adhesive 2 can effectively bond the battery cell 3 to the housing 1, in addition to applying the structural adhesive 3 between the bottom surface of the battery cell 3 and the housing 1, the structural adhesive 3 can also be applied between two adjacent battery cells 3 and between the two battery cells 3 at both ends and the inner wall of the housing 1.

[0048] According to one embodiment of the present invention, such as Figure 2As shown, cell 3 is a blade cell. S3 = W1 × L1 × K - S2 × (K-1), where W1 is the width of the bonding area between the structural adhesive 2 and cell 3 in the X direction of the housing; L1 is the length of the bonding area between the structural adhesive 2 and cell 3 in the Y direction of the housing, and the value range of L1 is 350mm ≤ L1 ≤ 470mm; K is the ratio of the surface area of ​​the insulating film 301 facing the structural adhesive 2 to the contour area corresponding to that surface area, and the value range of K is 1.3 ≤ K ≤ 1.6. For blade cells, this embodiment of the invention, by clarifying the specific calculation method of S3, can quantify the bonding area between the structural adhesive 2 and cell 3, providing a basis for the reasonable layout and dosage control of the structural adhesive 2, ensuring that the bonding of the structural adhesive 2 at different parts of cell 3 is more in line with the shape characteristics of cell 3. Furthermore, by limiting the specific value ranges of W1 and L1, the calculation of the bonding area can be made more in line with the actual size characteristics of the blade cell. In this way, it can ensure that there is enough bonding surface area between the structural adhesive layer 2 and the battery cell 3 to provide stable adhesion, avoiding the battery cell 3 being not firmly fixed due to insufficient area. It can also prevent excessive use of structural adhesive layer 2 due to excessive bonding area, which would increase the weight and cost of the battery pack. At the same time, standardized dimensional parameters help improve the consistency of battery pack assembly and production efficiency, and further optimize the overall performance of the battery pack.

[0049] It is understood that the value of L1 can be, but is not limited to, 350mm, 360mm, 370mm, 380mm, 390mm, 397mm, 428mm, 429mm, 452mm, 470mm or any value between the two.

[0050] It should be noted that, furthermore, 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, W1 and L1 in this embodiment are both average values ​​to reduce calculation errors. In addition, in this embodiment, the Y direction of the housing is the length direction of the housing 1.

[0051] It should be further explained 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 of the insulating film 301 multiplied by its width. After the insulating film 301 wraps around 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.

[0052] It should be noted that the value of K is also affected by the wave amplitude on the surface of the insulating film and the distance between two adjacent wave crests.

[0053] According to one embodiment of the present invention, such as Figure 2 As shown, the opening 3011 includes multiple square holes spaced apart along the Y direction of the housing 1, with the length direction of the square holes aligned with the Y direction of the housing 1; S2 = n × W2 × L2, where n is the number of square holes and is a positive integer greater than or equal to 1, W2 is the width of the square holes, with a value range of 8mm ≤ W2 ≤ 18mm; L2 is the length of the square holes, with a value range of 20mm ≤ L2 ≤ 35mm. In this embodiment, the opening 3011 is set as a square hole, which, compared to other shapes of opening 3011 such as round holes, can increase the opening ratio (i.e., the ratio of S2 to S1), increase the bonding surface area between the structural adhesive 2 and the battery cell housing, and improve the bonding strength. Furthermore, the bonding surface area S2 between the structural adhesive 2 and the battery cell housing is determined by the number of square holes n and the length L2 and width W2 of the square holes. Controlling L2 and W2 within a suitable range also means controlling S2 within a suitable range. If S2 is too small, the bonding surface area between the cell casing and the structural adhesive 2 will be small. If S2 is too large, it means that the insulation effect of the insulating film 301 on the cell casing will be worse, and poor insulation is likely to occur. At the same time, the manufacturing process of the insulating film 301 will also become more difficult, making it easier for dimensional deviations to occur and the yield rate to be difficult to guarantee.

[0054] Understandably, the value of W2 can be, but is not limited to, 8mm, 9mm, 9.5mm, 10mm, 12mm, 15mm, 18mm or any value between two of these; the value of L2 can be, but is not limited to, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26.1mm, 27mm, 29mm, 30mm, 31mm, 32mm, 33mm, 35mm or any value between two of these.

[0055] Furthermore, the number of circular holes can be between 12 and 18. Specifically, adaptive adjustments can be made according to design needs, and this utility model does not impose any special limitations on this.

[0056] Understandably, the shape of the opening 3011 can also be polygonal or elliptical, and specific adjustments can be made as needed.

[0057] According to one embodiment of the present invention, such as Figure 1As shown, the area corresponding to the insulating film 301 at the bottom surface of any cell 3 is S1, where S1 = W × L × K, where W is the width of the bottom surface of cell 3 in the X direction of the housing, and the value of W is in the range of 15mm ≤ W ≤ 28mm; L is the width of the bottom surface of cell 3 in the Y direction of the housing, and the value of L is in the range of 380 ≤ L ≤ 550mm; the relationship between W, W1, and W2 satisfies W2 < W1 < W; the relationship between S1 and S2 satisfies 18.75% ≤ S2 / S1 ≤ 34.62%. In the X direction of the housing 1, the width range of 15mm ≤ W ≤ 28mm ensures that cell 3 has sufficient volume to store energy, while avoiding uneven distribution of structural adhesive 2 on the bottom surface of cell 3 due to excessive width, which would affect the bonding effect. The W2 < W1 < W relationship ensures that the diameter W2 of the opening 3011 is smaller than the relevant dimension W1 of the insulating film 301, while W1 is smaller than the width W of the cell 3. This hierarchical relationship results in a reasonable distribution of the bonding areas between the structural adhesive 2 and the insulating film 301 and the cell shell, effectively dispersing stress and improving the overall connection strength. In the Y direction of the housing 1, a width range of 380 ≤ L ≤ 550 mm satisfies the energy density requirements of the battery pack and provides the cell 3 with suitable dimensions in the Y direction, facilitating the side-by-side arrangement of multiple cells 3 along the X direction. Furthermore, this dimensional design optimizes the internal space utilization of the battery pack, reduces unnecessary volume waste, helps improve the overall energy density and heat dissipation performance of the battery pack, and extends the battery pack's lifespan. This embodiment of the invention, by controlling the values ​​of S2 / S1 within a suitable range, can balance the bonding surface area between the structural adhesive 2 and the insulating film 301, as well as the bonding surface area between the structural adhesive 2 and the cell shell. If the value of S2 / S1 is too large, it means that the area of ​​the opening 3011 is too large, which may lead to the risk of insulation failure. If the value of S2 / S1 is too small, it means that the bonding surface area between the cell shell and the structural adhesive 2 is too small, making it difficult to effectively improve the bonding strength between the two.

[0058] It is understood that the value of W can be, but is not limited to, 15mm, 16.2mm, 17.2mm, 18mm, 18.7mm, 19.5mm, 21.6mm, 25mm, 28mm or any value between two of these; the value of L can be, but is not limited to, 380mm, 410mm, 445mm, 465mm, 495mm, 520mm, 550mm or any value between two of these.

[0059] It should be noted that W is the distance between two opposite surfaces of the battery cell 3 in the X direction of the housing, and W is the width of the insulating film 301 located on the bottom surface of the battery cell in the X direction of the housing; L is the distance between two opposite surfaces of the battery cell 3 in the Y direction of the housing, and L is the length of the insulating film 301 located on the bottom surface of the battery cell in the Y direction of the housing.

[0060] According to one embodiment of this utility model, along the Z direction of the housing 1, a gap is left between the opposite sides of the opening 3011 and the corresponding edge of the structural adhesive 2, and the relationship between W1 and W2 satisfies: 1.5mm≤(W1-W2) / 2≤3mm. By limiting the gap between the opposite sides of the opening 3011 and the corresponding edge of the structural adhesive 2, and clearly defining the relationship of 1.5mm≤(W1-W2) / 2≤3mm, this embodiment of the utility model can not only avoid the bonding surface area between the structural adhesive 2 and the insulating film 301 being too small due to the distance between the opening 3011 and the edge of the structural adhesive 2 being too close, but also prevent the excessive amount of structural adhesive 2 from being used due to excessively large gaps, which would affect production costs and assembly space.

[0061] According to one embodiment of the present invention, such as Figure 2 As shown, along the X direction of the housing 1, the distance between the opposite sides of the square hole and the corresponding edge of the battery cell housing is A, and the value of A is in the range of 3.5mm≤A≤6.5mm; along the Y direction of the housing 1, the interval between two adjacent square holes is B, and the value of B is in the range of B≥8mm. Limiting the distance A between the opposite sides of the square hole and the corresponding edge of the battery cell housing to 3.5mm to 6.5mm along the X direction of the housing provides sufficient insulation protection space for the edge of the battery cell housing, avoiding safety hazards caused by insufficient coverage of the insulation film 301 due to excessively small distances, and also preventing the waste of effective bonding surface area on the bottom surface of the battery cell 3 due to excessively large distances. Setting the interval B≥8mm between adjacent square holes along the Y direction of the housing ensures that the structural adhesive 2 at each opening 3011 is subjected to relatively independent force, reducing mutual interference and making the bonding of the structural adhesive 2 to the battery cell housing through each square hole more uniform and reliable.

[0062] It is understood that the value of A can be, but is not limited to, 3.5mm, 4.1mm, 4.35mm, 4.6mm, 4.75mm, 5mm, 5.8mm, 6.5mm or any value between two of these; the value of B can be, but is not limited to, 8mm, 8.1mm, 8.4mm, 8.9mm, 9.7mm, 9.8mm, 10mm, 10.5mm, 10.8mm or 11mm.

[0063] According to one embodiment of this utility model, 4.5 MPa ≤ β ≤ 7 MPa. It can be understood that the range of 4.5 MPa ≤ β ≤ 7 MPa ensures that the shear strength of the bond between the structural adhesive 2 and the insulating film 301 is at a reasonable level, so that the bonding of the insulating film 301 in the (S1-S2) portion can provide stable shear force.

[0064] It is understood that the value of β can be, but is not limited to, 4.5 MPa, 4.8 MPa, 5 MPa, 5.1 MPa, 5.3 MPa, 5.5 MPa, 5.6 MPa, 6.3 MPa, 6.5 MPa, 7 MPa, or any value between the two.

[0065] According to one embodiment of this utility model, 3.5 MPa ≤ γ ≤ 5 MPa. This setting of 3.5 MPa ≤ γ ≤ 5 MPa enhances the shear strength of the structural adhesive 2 directly bonded to the battery cell casing through the opening 3011, making the direct bonding contribution of the S2 part more reliable.

[0066] It is understood that the value of γ can be, but is not limited to, 3.5 MPa, 3.6 MPa, 3.7 MPa, 3.8 MPa, 4.3 MPa, 5 MPa or any value between the two.

[0067] According to one embodiment of the present invention, such as Figure 3 As shown, the amplitude of the wave on the surface of the insulating film 301 is C, and the value of C ranges from 15μm to 40μm. The distance between two adjacent wave crests is D, and the value of D ranges from 120μm to 200μm. This embodiment of the invention limits C to between 15μm and 40μm and D to between 120μm and 200μm, which increases the contact area and friction between the structural adhesive 2 and the insulating film 301, thereby improving the bonding strength.

[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 this embodiment 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 this utility model 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" (GB38031-2020).

[0073] Table 1

[0074]

[0075]

[0076] As can be seen, after simulation analysis and vibration testing, the insulating film 301 of the battery packs in Examples 1 to 10 did not exhibit any tearing problems, and the insulating film 301 and structural adhesive 2 were not easily separated. After insulation withstand voltage testing, the battery packs in Examples 1 to 10 did not exhibit any insulation defects. However, after the cell 3 withstand voltage test, the battery pack in Comparative Example 1 exhibited insulation defects due to a small A value. The battery pack in Comparative Example 2, due to a small B value, experienced deformation of the openings 3011 on the insulating film 301 caused by unstable belt tension during the production process, leading to a higher defect rate in the area and edge distance of the openings 3011 after cell 3 encapsulation. After simulation analysis and vibration testing, the battery pack in Comparative Example 3 exhibited tearing problems at the insulating film 301, and the insulating film 301 was easily separated from the structural adhesive 2. The reason is that the A value is too large, resulting in insufficient area of ​​the opening 3011, which in turn leads to insufficient bonding strength between the structural adhesive 2 and the battery cell 3. The battery pack of Comparative Example 3 did not exhibit insulation failure after the insulation withstand voltage test. It should be noted that the insulating film 301 wrapped around the battery cell 3 in the battery packs of 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] It should be noted that the insulation withstand voltage test process for the battery packs in the above embodiments and the comparative battery packs is as follows:

[0078] First, a DC withstand voltage test is performed, applying a voltage of 3500VDC for 2 seconds. During this process, the leakage current must be monitored and must be less than 2mA. Next, an AC withstand voltage test is performed, applying a voltage of 2350VAC for 2 seconds, again with the leakage current controlled to be less than 2mA. Throughout the entire testing process, it is essential to ensure stable voltage application, precise time control, and close monitoring of leakage current changes to comprehensively verify whether the cell's insulation withstand voltage performance meets the standards.

[0079] It should be noted that, in this embodiment, γ and β along the X direction of housing 1 can be obtained using measuring tools such as a universal tensile testing machine. Specifically, the testing standard for obtaining γ and β is GB / T7124.

[0080] Taking the bonding strength γ between insulating film 301 and structural adhesive 2 as an example, the process of obtaining its specific value using a universal tensile testing machine is as follows:

[0081] Shear specimens were prepared according to GB / T7124. Two shear specimens with dimensions of 100mm × 25mm × 2mm were cut. Structural adhesive 2 was applied to one side of the insulating film 301 of both shear specimens, with a bonding area of ​​25mm × 25mm between the insulating film 301 and the structural adhesive 2. The two shear specimens were then fixed together. Al3003 test pieces were used for the shear specimens, and PET film was used for the insulating film 301. The shear specimens were repeatedly rolled with a 2kg roller at least five times and then left to stand at room temperature (23±2℃) for 24 hours. Testing then began. The two bonded shear specimens were fixed to fixtures, and a universal tensile testing machine was used to stretch the upper end of one shear specimen and the lower end of the other at a stretching speed of 50mm / min. The stress on the shear specimen was divided by the bonding surface area of ​​25mm × 25mm to obtain the bond strength γ.

[0082] 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 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. Along the Z-direction of the housing, the structural adhesive is located between the bottom surfaces of the plurality of battery cells and the bottom surface of the housing; the bonding surface area between the bottom surface of any battery cell and the structural adhesive is S3; the insulating film located on the bottom surface of the battery cell has an opening, the area of ​​which is S2; a portion of the structural adhesive is bonded to the battery cell housing through the opening; The adhesive strength between the structural adhesive and the insulating film is γ, and the adhesive strength between the structural adhesive and the cell case is β; S3, S2, γ, and β satisfy: 1.7 x 10 4 N ≤ (S3 - S2) x γ + S2 x β ≤ 5.0 x 10 4 N.

2. The battery pack of claim 1, wherein, The battery cell is a blade battery cell, S3 = W1 × L1 × K - S2 × (K - 1), where W1 is the width of the bonding part between the structural adhesive and the battery cell in the X direction of the housing; L1 is the length of the bonding part between the structural adhesive and the battery cell in the Y direction of the housing, and the value range of L1 is: 350mm ≤ L1 ≤ 470mm; K is the ratio of the surface area of ​​the insulating film facing the structural adhesive to the contour area corresponding to the surface area, and the value range of K is: 1.3 ≤ K ≤ 1.

6.

3. The battery pack of claim 2, wherein, The opening includes a plurality of square holes spaced apart along the Y direction of the housing, the length direction of the square holes being consistent with the Y direction of the housing; S2 = n × W2 × L2, where n is the number of square holes and is a positive integer greater than or equal to 1, W2 is the width of the square holes, and the value range of W2 is: 8mm ≤ W2 ≤ 18mm; L2 is the length of the square holes, and the value range of L2 is: 20mm ≤ L2 ≤ 35mm.

4. The battery pack of claim 3, wherein, The area corresponding to the insulating film at the bottom surface of any of the battery cells is S1; S1 = W × L × K, where W is the width of the bottom surface of the battery cell in the X direction of the housing, and the value of W is in the range of 15mm ≤ W ≤ 28mm; L is the width of the bottom surface of the battery cell in the Y direction of the housing, and the value of L is in the range of 380 ≤ L ≤ 550mm; the relationship between W, W1, and W2 satisfies W2 < W1 < W; the relationship between S1 and S2 satisfies 18.75% ≤ S2 / S1 ≤ 34.62%.

5. The battery pack of claim 4, wherein, Along the Z direction of the box body, there is a gap between the opposite sides of the opening and the corresponding edge of the structural adhesive, and the relationship between W1 and W2 satisfies: 1.5mm≤(W1-W2) / 2≤3mm.

6. The battery pack of claim 3, wherein, Along the X direction of the housing, the distance between the opposite two sides of the square hole and the corresponding edge of the battery cell housing is A, and the value of A is in the range of 3.5mm≤A≤6.5mm; along the Y direction of the housing, the interval between two adjacent square holes is B, and the value of B is in the range of B≥8mm.

7. The battery pack of any one of claims 1-6, wherein, 4.5 MPa ≤ β ≤ 7 MPa.

8. The battery pack of any one of claims 1-6, wherein, 3 MPa ≤ γ ≤ 5 MPa.

9. The battery pack of any one of claims 1-6, wherein, The amplitude of the wave on the surface of the insulating film is C, and the value of C is in the range of 15μm≤C≤40μm. The distance between two adjacent wave crests in the wave is D, and the value of D is in the range of 120μm≤D≤200μm.

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

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