Battery device, energy storage device, and electric device

Abstract

The application relates to a battery device, an energy storage device and an electric equipment. The battery device comprises a battery cell assembly and a shell assembly. The battery cell assembly comprises a plurality of battery cells arranged along a first direction, and each battery cell comprises oppositely arranged upper and lower surfaces. The shell assembly comprises a fastener, which comprises at least one first fastener and at least one second fastener. The first fastener is located between the upper surface and the second fastener, and the first fastener and the second fastener are both arranged in the circumferential direction of the battery cell assembly. The length of the first fastener along a second direction is greater than the length of the second fastener along the second direction. The second direction is perpendicular to the first direction. The sum of the length of the first fastener along the second direction and the length of the second steel belt along the second direction is L, the length of the battery cell assembly along the second direction is H, and L <= 1 / 3H. The battery device can control the expansion of the top of the battery cell, balance the load pressure of the bottom and the top of the battery, and improve the structural stability of the battery device.

Description

Technical Field

[0001] This invention relates to the field of energy storage, and more specifically to a battery device, an energy storage device, and an electrical appliance. Background Technology

[0002] With the rapid development of the new energy industry, rechargeable batteries are widely used in energy storage systems and various electrical devices. Battery devices typically consist of cell assemblies and a housing assembly. The cell assemblies are housed within the housing assembly, which provides support to maintain the overall structural stability of the battery device. Currently, the reliability of the housing assembly needs improvement. Summary of the Invention

[0003] This application proposes a battery device, energy storage device, and electrical equipment that helps control the expansion of the top of the battery cell, balance the load pressure at the bottom and top of the battery cell, improve the overall structural stability of the battery device, and at the same time improve heat dissipation efficiency and reduce costs.

[0004] In a first aspect, embodiments of this application provide a battery device, the battery device comprising: A battery cell assembly, the battery cell assembly comprising a plurality of battery cells arranged along a first direction, the battery cells comprising an upper surface and a lower surface disposed opposite to each other; A housing assembly, the housing assembly including fasteners, the fasteners including at least one first fastener and at least one second fastener, the first fastener being located between the upper surface and the second fastener, the first fastener and the second fastener both surrounding the cell assembly in the circumferential direction. The length of the first fastener along the second direction is greater than the length of the second fastener along the second direction. The second direction is perpendicular to the first direction. The sum of the lengths of the first fastener along the second direction and the lengths of the second fastener along the second direction is L. The length of the battery cell assembly along the second direction is denoted as H. L≤1 / 3H.

[0005] Secondly, embodiments of this application provide an energy storage device, the energy storage device including the battery device described in the first aspect, the battery device being used to store electrical energy.

[0006] Thirdly, embodiments of this application provide an electrical device, which includes the battery device described in the first aspect, and the battery device is used to provide electrical energy.

[0007] Compared with the prior art, this technical solution has at least the following technical advantages: During the use of battery devices, due to the assembly structure and force distribution of the battery cell assembly, the expansion of the top of the battery cell in the battery cell assembly is usually greater than the expansion of the bottom of the battery cell. This embodiment of the application incorporates a first fastener and a second fastener within the housing assembly. The first fastener is positioned higher than the second fastener, and its length along the second direction is greater than that of the second fastener, meaning the width of the first fastener is greater than that of the second fastener. This design effectively limits excessive expansion deformation at the top of the battery cell assembly, and the second fastener effectively limits excessive expansion deformation at the bottom of the battery cell assembly. This balances the load pressure at the top and bottom of the battery cell assembly, improving the overall structural stability of the battery device. Simultaneously, the sum of the widths of the first and second fasteners is less than or equal to one-third of the width of the entire battery cell assembly. On one hand, the first and second fasteners provide appropriate pre-tightening force to the battery cell assembly, preventing excessive compression of the cells by overly tight fasteners and effectively constraining cell expansion, thus reducing cell gaps. On the other hand, the first and second fasteners minimize obstruction of the battery cell assembly, preventing them from excessively encroaching on the heat dissipation path and space of the cells, ensuring the heat dissipation effect of the battery device, and reducing costs. Attached Figure Description

[0008] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0009] Figure 1 A schematic diagram of the structure of a battery device provided in an embodiment of this application; Figure 2 This is an exploded view of two adjacent battery cells provided in an embodiment of this application; Figure 3 A schematic diagram of a heat insulation board and elastic structure provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of an end plate provided in an embodiment of this application; Figure 5 This is another schematic diagram of the battery device provided in the embodiments of this application; Figure 6 for Figure 5 A magnified view of a portion of region I; Figure 7 This is a schematic diagram of another structure of the end plate provided in an embodiment of this application.

[0010] Figure label: 100-Battery Unit; 1-Battery cell assembly; 11-Cell; 11A-Upper surface; 11B-Lower surface; 12-Elastic structure; 13-Insulation board; 2-Housing assembly; 21-Fastener; 211-First fastener; 212-Second fastener; 22-Frame; 23-End plate; 23A-Central area; 23B-Edge area; 231 - First mounting slot; 232 - Second mounting slot; 233-Concave structure; 24 - First insulating sleeve; 25 - Second insulating sleeve; 26 - Third insulating sleeve; 27 - Fourth insulating sleeve. Detailed Implementation

[0011] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0012] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0013] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0014] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0015] For ease of description, the length direction of the battery device is defined as the X-axis, the width direction as the Y-axis, and the thickness direction as the Z-axis. The X-axis, Y-axis, and Z-axis are all perpendicular to each other.

[0016] The directional terms such as "upper," "lower," "top," "bottom," "left," "right," "front," and "rear" used in the description of the battery device in this application are mainly based on the battery device's location in the attached... Figure 1The display orientation is described using the positive Z-axis direction as "top" or "up", the negative Z-axis direction as "bottom" or "down", the positive X-axis direction as "right", the negative X-axis direction as "left", the positive Y-axis direction as "back", and the negative Y-axis direction as "front". This does not constitute a limitation on the orientation of the battery device in actual application scenarios.

[0017] In the accompanying drawings corresponding to the embodiments of this application, the thickness of structures such as layers, films, plates, and regions is enlarged for better understanding and ease of description. The same reference numerals are used throughout the specification to refer to the same or similar elements. When describing a component (such as a layer, film, plate, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when it is mentioned that a component is "directly located" on another component, it indicates that there is no third component between the two components.

[0018] The terms "first," "second," etc., used in this application are only used to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features.

[0019] This application provides a battery device. Figure 1 This is a schematic diagram of the structure of a battery device 100 provided in an embodiment of this application, as shown below. Figure 1 As shown, the battery device 100 includes: The battery cell assembly 1 includes a plurality of battery cells 11 arranged along a first direction, and each battery cell 11 includes an upper surface 11A and a lower surface 11B disposed opposite to each other. The housing assembly 2 includes a fastener 21, which includes at least one first fastener 211 and at least one second fastener 212. The first fastener 211 is located between the upper surface 11A and the second fastener 212, and both the first fastener 211 and the second fastener 212 are wrapped around the cell assembly 1 in the circumferential direction. The length of the first fastener 211 along the second direction is greater than the length of the second fastener 212 along the second direction. The second direction is perpendicular to the first direction. The sum of the lengths of the first fastener 211 and the second fastener 212 along the second direction is L. The length of the battery cell assembly 1 along the second direction is denoted as H. L≤1 / 3H.

[0020] During the use of the battery device 100, due to the assembly structure and force distribution of the cell assembly 1, the expansion of the top of the cell 11 in the cell assembly 1 is usually greater than the expansion of the bottom of the cell 11. In this embodiment, by providing a first fastener 211 and a second fastener 212 in the housing assembly 2, the first fastener 211 is positioned higher than the second fastener 212, and the length of the first fastener 211 along the second direction is greater than the length of the second fastener 212 along the second direction, i.e., the width of the first fastener 211 is greater than the width of the second fastener 212. The first fastener 211 can effectively limit the excessive expansion deformation of the top of the cell assembly 1, and the second fastener 212 can effectively limit the excessive expansion deformation of the bottom of the cell assembly 1, thereby balancing the load pressure on the bottom and top of the cell assembly 1 and improving the overall structural stability of the battery device 100; simultaneously, the first fastener 211... The sum of the widths of the first fastener 211 and the second fastener 212 is less than or equal to 1 / 3 of the width of the entire cell assembly 1. On the one hand, the first fastener 211 and the second fastener 212 provide appropriate pre-tightening force for the cell assembly 1, which can prevent the first fastener 211 and the second fastener 212 from excessively compressing the cell 11 inside the cell assembly 1, and can also effectively constrain the expansion of the cell 11 and reduce the gap between the cell 11. On the other hand, the first fastener 211 and the second fastener 212 obstruct the cell assembly 1 less, which can prevent the first fastener 211 and the second fastener 212 from excessively encroaching on the heat dissipation path and space of the cell 11, thus ensuring the heat dissipation effect of the battery device 100 and reducing costs.

[0021] The battery device 100 provided in this application embodiment can be widely used in battery fields requiring high energy density and long cycle life, achieving a comprehensive improvement in energy density, cycle life, and safety performance. Especially in the field of long-term energy storage, the battery device 100 can stably meet continuous discharge requirements of 4 hours or more, and easily cover energy storage conditions of 5 hours, 6 hours, or even more than 8 hours. Long-term energy storage refers to the ability to continuously discharge for 4 hours or even longer at rated power, or to achieve large-scale, low-cost energy storage for several days or months.

[0022] The embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0023] Combination Figure 1 This application provides a battery device 100, which includes a cell assembly 1 and a housing assembly 2. The battery device 100 has intersecting and perpendicular first, second, and third directions, wherein the first direction is defined as the length direction of the battery device 100, i.e. Figure 1 The X-axis direction shown is defined as the direction of the height of the battery device 100, i.e. Figure 1 The Z-axis direction shown is defined as the width direction of the battery device 100, i.e. Figure 1 The Y-axis direction is shown.

[0024] Continue as Figure 1 As shown, the battery cell assembly 1 includes a plurality of battery cells 11 arranged along the X-axis direction. The battery cells 11 serve as the basic units for storing and releasing electrical energy in the battery device 100.

[0025] In some embodiments, the battery cell 11 of this application can be a secondary battery, a rechargeable battery, or a storage battery, wherein a secondary battery refers to a battery that can recharge itself after discharging to activate its internal active materials and restore electrical energy.

[0026] In some embodiments, the battery cell 11 includes at least one of lithium iron phosphate battery (LFP), ternary lithium battery (NMC or Nickel Cobalt Aluminum, NCA), sodium-ion battery (SIB), or lithium manganate battery (LMO).

[0027] In some embodiments, the number of battery cells 11 can be set according to actual needs. For example, the number of multiple battery cells 11 can be 4, 8, 12, 16 or 24, and no specific limitation is made here.

[0028] In some embodiments, the battery cell 11 has a square shell structure, and its regular shape is conducive to tight stacking in the X-axis direction, thereby improving the space utilization and energy density of the battery device 100.

[0029] In some embodiments, the cell assembly 1 further includes an electrode connection assembly (not shown in the figures), which is disposed between and electrically connected to two adjacent cells 11, for transmitting the parameters or status electrical signals of the cell 11 to an external circuit.

[0030] Continue as Figure 1 As shown, the housing assembly 2 includes a fastener 21, which includes at least one first fastener 211 and at least one second fastener 212. The first fastener 211 and the second fastener 212 are both surrounding the cell assembly 1 in the circumferential direction, providing a circumferential rigid constraint force for the entire cell assembly 1.

[0031] The battery cell 11 includes an upper surface 11A and a lower surface 11B disposed opposite to each other. A first fastener 211 is located between the upper surface 11A and a second fastener 212. The first fastener 211 is used to provide a rigid constraint force for the top of the battery cell 11, and the second fastener 212 is used to provide a rigid constraint force for the bottom of the battery cell 11. The first fastener 211 is simply referred to as the top steel strip, and the second fastener 212 is simply referred to as the bottom steel strip.

[0032] It should be noted that "top" and "bottom" are two different and relative concepts. The top is close to the upper surface 11A of the battery cell 11, and the bottom is close to the lower surface 11B of the battery cell 11. This application only defines the approximate positions of the first fastener 211 and the second fastener 212, and does not define the precise positions of the first fastener 211 and the second fastener 212.

[0033] Continue as Figure 1 As shown, the second direction is defined as the direction parallel to the Z-axis of the battery device 100. The length of the first fastener 211 along the second direction is the width of the first fastener 211, and the length of the second fastener 212 along the second direction is the width of the second fastener 212. The width of the first fastener 211 is greater than the width of the second fastener 212. The wider first fastener 211 can provide a stronger constraint force for the cell assembly 1, while the narrower second fastener 212 can provide a weaker constraint force for the cell assembly 1. The first fastener 211 and the second fastener 212 work together to constrain the expansion of the top of the cell while balancing the load pressure at the bottom and top of the cell assembly 1, ensuring the overall structural stability of the battery device 100.

[0034] The sum of the lengths of the first fastener 211 and the second fastener 212 along the second direction is L. The length of the battery cell assembly 1 along the second direction is denoted as H, where L ≤ 1 / 3H. Specifically, L can be 1 / 3H, 1 / 5H, 1 / 7H, 1 / 10H, 1 / 13H, 1 / 15H, 1 / 20H, etc. Optionally, 1 / 10H ≤ L ≤ 1 / 3H.

[0035] In this application, L is the total width of the first fastener 211 and the second fastener 212, and H is the height of the cell assembly 1. By controlling L≤1 / 3H, on the one hand, the first fastener 211 and the second fastener 212 provide appropriate pre-tightening force for the cell assembly 1, which can avoid excessive compression of the cell assembly 1 by the first fastener 211 and the second fastener 212 due to excessive tightness, and can also effectively constrain the volume expansion of the cell assembly 1 and reduce the gap between the cells 11; on the other hand, the first fastener 211 and the second fastener 212 block the cell assembly 1 less, avoiding excessive encroachment of the heat dissipation path and space of the cell 11 by the first fastener 211 and the second fastener 212, ensuring the heat dissipation effect of the battery device 100, while reducing costs.

[0036] In some embodiments, H is 90mm~220mm, specifically 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm.

[0037] In some embodiments, the number of first fasteners 211 is greater than or equal to 1, for example, it can be 1, 2, 3, 4, 5, etc. The number of second fasteners 212 is greater than or equal to 1, for example, it can be 1, 2, 3, 4, 5, etc.

[0038] When the number of first fasteners 211 is 1 and the number of second fasteners 212 is 1, L is the sum of the widths of one first fastener 211 and one second fastener 212. When the number of first fasteners 211 is ≥2 and the number of second fasteners 212 is ≥2, L is the sum of the widths of all first fasteners 211 and the sum of the widths of all second fasteners 212.

[0039] In some embodiments, the first fastener 211 and the second fastener 212 may be made of LH201 stainless steel strip, 304 stainless steel strip, etc.

[0040] In some embodiments, Figure 2 This is a schematic diagram of the explosion of two adjacent battery cells, as shown below. Figure 1 and Figure 2 As shown, at least some adjacent cells 11 are provided with an elastic structure 12. The elastic structure 12 can absorb the expansion force of the cells 11, which helps to reduce the load pressure of the fastener 21.

[0041] In some embodiments, the elastic structure 12 is foam, which is a sheet-like material sandwiched between adjacent battery cells 11. At least one surface of the foam is provided with adhesive, which is used to bond the foam and the battery cells 11. In the battery cell assembly 1, after multiple battery cells 11 are stacked, the foam completely fills the gaps between the battery cells 11 to buffer the expansion of the battery cells 11 during charging and discharging.

[0042] In some embodiments, the thermal conductivity of the elastic structure 12 is 0.020 W / m / K to 0.080 W / m / K, specifically it can be any value within the range of 0.020 W / m / K, 0.030 W / m / K, 0.040 W / m / K, 0.050 W / m / K, 0.060 W / m / K, 0.070 W / m / K, 0.080 W / m / K, or any two of the above values. Controlling the thermal conductivity of the elastic structure 12 within the above range results in a lower thermal conductivity, which is beneficial for controlling the propagation of thermal runaway between adjacent cells 11. Optionally, the thermal conductivity of the elastic structure 12 is 0.020 W / m / K to 0.030 W / m / K.

[0043] It should be noted that the thermal conductivity of the elastic structure 12 was tested at 24±1℃.

[0044] In some embodiments, the thickness of the elastic structure 12 is 0.7 mm to 20 mm, specifically it can be 0.7 mm, 1 mm, 3 mm, 5 mm, 7 mm, 10 mm, 13 mm, 15 mm, 18 mm, 20 mm or any value within the range of any two of the above values.

[0045] In some embodiments, the elastic structure 12 comprises a polypropylene material, further comprising a flame-retardant grade polypropylene microporous foam material.

[0046] In some embodiments, the elastic structure 12 includes a ceramicized silicone foam material, which maintains a certain elasticity at room temperature and transforms into a dense and hard ceramic material at high temperature, thus blocking the propagation of thermal runaway between the battery cells 11.

[0047] In some embodiments, the compressive force of the elastic structure 12 under a compressive deformation of 20% to 40% is F1 (N). When the battery cell assembly 1 is fully charged, the first fastener 211 has a binding force F2 (N), where F1 / F2 = 0.5 to 1.5. Specifically, F1 / F2 can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, or any value within the range of any two of the above values. By controlling F1 / F2 within the above range, the first fastener 211 can tolerate the normal expansion deformation of the battery cell assembly 1 during charging and discharging, while ensuring that the overall structure of the battery device 100 remains unchanged and does not loosen. This helps to achieve a balance between the controllability of the expansion of the battery cell 11 and the stability of the structure.

[0048] It should be noted that "fully charged state" refers to the state of charge (SOC) of cell component 1 at 90%~100%.

[0049] The testing procedure for the compressive force F1 of the elastic structure 12 under 20%~40% compressive deformation includes: taking the test of the compressive force F1 of the elastic structure 12 under 20% compressive deformation as an example, firstly, a standard elastic structure specimen (e.g., 50mm×50mm×25mm) with a smooth and defect-free surface is prepared and placed in a standard laboratory environment (23±2℃, 50±5%RH) for at least 16 hours. Using a universal testing machine, the compression speed is set to 100mm / min, and the specimen is pre-compressed twice (usually compressed to 75%~80% of the initial thickness and then unloaded) to eliminate the influence of stress history. Then, the compression test is performed again, and the compressive force value of the elastic structure 12 when the compressive deformation reaches 20% is recorded. The average value of at least three specimens is taken as the final compressive force F1 result.

[0050] The binding force F2 of the first fastener 211 is tested using a force sensor and a direct tension test method. The specific test steps include: First, using a servo constant tension test system or a dedicated tension force tester equipped with a high-precision force sensor (such as a tension / compression sensor); After the equipment is turned on and preheated and stabilized, the system is zeroed in an unstressed state to eliminate the interference of initial residual stress; then, the battery cell assembly bundled with the first fastener is placed stably on the test platform, the force-bearing end of the sensor is connected to the initial binding force point of the fastener (such as the overlap or the test hole reserved on the end plate), and the position is adjusted to ensure that the line of action of the tension is collinear with the tension direction of the first fastener; finally, the test program is started, and a reverse tension is applied at a very low constant speed (such as 1 mm / min ~ 5 mm / min) or a static holding mode is used. When the force curve of the sensor reaches the first stable peak, the force value is recorded as the binding force F2. Usually, the test is repeated 3 times and the arithmetic mean is taken to ensure the reliability of the data.

[0051] This application defines the total number of battery cell cycles as N. The total number of battery cell cycles N refers to the number of complete charge-discharge cycles that the battery cell can complete before its capacity decays to a specific threshold (usually 80% of the initial capacity) after multiple charge-discharge cycles. N = 8000~15000, optionally, N = 8000~12000.

[0052] Cell assembly 1 has a first state, a second state, and a third state, wherein: The first state is the state corresponding to when the number of cycles of cell assembly 1 is the first number of cycles, which is (0~1 / 2). N. It should be noted that when the first cycle count is 0, cell assembly 1 is in an unused state.

[0053] The second state is the state corresponding to the number of cycles of cell assembly 1 being the second number of cycles, which is (1 / 2~2 / 3). N.

[0054] The third state corresponds to the state when the number of cycles for cell assembly 1 is the third cycle number, which is (2 / 3~1). N. It should be noted that when the third cycle number is N, that is, when cell assembly 1 is at the end of its life (EOL).

[0055] In some embodiments, Figure 3 A schematic diagram of a structure for an insulation panel and an elastic structure is shown, such as... Figures 1-3 As shown, a heat insulation plate 13 is provided between at least some of the adjacent battery cells 11, and an elastic structure 12 is provided on the heat insulation plate 13 to further enhance the heat insulation effect between adjacent battery cells 11, which is conducive to blocking the thermal runaway propagation between adjacent battery cells 11, while ensuring the fixation effect of the elastic structure 12.

[0056] In some embodiments, a plurality of sheet-like elastic structures are provided on one side surface of the heat insulation plate 13, such as... Figure 3 As shown, three elastic structures 12 are provided on one side surface of the heat insulation board 13. The three elastic structures 12 are located at the top, middle and bottom of the heat insulation board 13, respectively. In this way, the elastic structures 12 can provide excellent expansion buffering effect and reduce the use of elastic structures 12, thereby reducing costs.

[0057] In some embodiments, the elastic structure 12 is bonded to one side surface of the heat insulation plate 13, and the other side of the heat insulation plate 13 is bonded to the side wall of the battery cell 11.

[0058] In some embodiments, the main material of the heat insulation board 13 is silicon dioxide, which has good heat insulation effect and good insulation and pressure resistance.

[0059] In some embodiments, continue as follows Figure 1 As shown, housing assembly 2 also includes an adhesive layer (not on) Figure 1 As shown in the figure, the frame 22 supports and fixes multiple battery cells 11 together in an orderly manner through multiple connecting plates, mounting plates and other structures to form a complete protective support frame. The first fastener 211 and the second fastener 212 are arranged around the frame 22 in the circumferential direction. The multiple battery cells 11 are fixed to the frame 22 by an adhesive layer. The first fastener 211 and the second fastener 212 are used to bind the frame 22, which contains multiple battery cells 11, as a whole.

[0060] In some embodiments, the adhesive layer is made of thermally conductive polyurethane structural adhesive, thermally conductive silicone, thermally conductive epoxy structural adhesive, and acrylic structural adhesive, etc. The adhesive layer can not only effectively fix the battery cell 11 and absorb the expansion stress of the battery cell 11 during the expansion process, and alleviate the bottom expansion of the battery cell assembly 1, but also serve as a buffer component between the battery cell 11 and the frame 22, reducing the cracking and deformation of the battery cell 11.

[0061] In some embodiments, the thickness of the adhesive layer is 0.3 mm to 1.0 mm, specifically 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1.0 mm, or any value within the range of any two of the above values.

[0062] In some embodiments, when the ratio of the length of the first fastener 211 along the second direction to the length of the second fastener 212 along the second direction is greater than or equal to 1.5, the shear strength at the point where the adhesive layer adheres to the plurality of battery cells 11 and the frame 22 is T (N / mm²). 2 The peel strength at the bonding point between the adhesive layer and multiple battery cells 11 and frame 22 is P (N / mm), and T / P ≥ 3.

[0063] When the ratio of the length of the first fastener 211 along the second direction to the length of the second fastener 212 along the second direction is greater than or equal to 1.5, T / P can specifically be 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, or any value within the range of any two of the above values. Controlling T / P ≥ 3 indicates that under the synergistic restraint of the first fastener 211 and the second fastener 212, the shear strength of the adhesive layer is greater than or equal to 3 times the peel strength. On the one hand, the larger shear strength can firmly fix the bottom of the battery cell assembly 1 to the frame 22, effectively controlling the slippage of the battery cell assembly 1 during expansion; on the other hand, the smaller peel strength can effectively buffer the expansion of the top of the battery cell assembly 1, allowing the adhesive layer to produce slight deformation to release stress when the battery cell assembly 1 expands excessively. Furthermore, when the cell assembly 1 expands dramatically, the adhesive layer is more likely to undergo cohesive failure, causing it to tear rather than peel off from the cell 11 or the frame 22. This helps maintain a tight fit between the adhesive layer and the multiple cells 11 and the frame 22, thus improving the structural rigidity, vibration and impact resistance, and lateral displacement resistance of the battery device 100. Optionally, 10 ≥ T / P ≥ 3.

[0064] The shear strength at the interface between the adhesive layer and multiple battery cells 11 and the frame 22 refers to the adhesive layer's ability to resist external forces parallel to the bonding interface direction of the battery cells 11 and the frame 22. For example, the shear strength can be tested using the following method: A sample containing the adhesive layer, battery cells 11, and frame 22 (width 25±0.2 mm, overlap length 12.5±0.2 mm) is cut from the battery device. A tensile load is applied at a constant loading rate of 1 mm / min to 2 mm / min using a universal testing machine until the adhesive layer completely fails. The maximum failure load (F) is recorded, and the shear strength is calculated using the formula τ=F / (b×l) (where b is the sample width and l is the overlap length). The arithmetic mean of at least five samples is taken as the final result.

[0065] The peel strength at the point where the adhesive layer is bonded to multiple battery cells 11 and the frame 22 refers to the maximum force required to peel the adhesive layer from the point where it is bonded to the battery cells 11 and the frame 22 at a 90° angle. It measures the adhesive layer's ability to resist external forces perpendicular to the bonding interface. For example, the peel strength can be tested as follows: a sample (typically 25 mm wide) containing the adhesive layer, battery cells 11, and frame 22 is cut from the battery device. One end of the adhesive layer is peeled from the frame 22 at a 90° right angle. A tensile force is applied at a constant rate of 50–200 mm / min using a universal testing machine. The force value during the peeling process is continuously recorded. The average peel force during the stable peeling phase is divided by the sample width (N / mm) to obtain the peel strength result. At least 5 samples should be tested and the average value taken to ensure data reliability.

[0066] It should be noted that the units of shear strength T and peel strength P are different. The range of the T / P ratio is an empirical threshold obtained by the applicant based on a large number of battery device 100 expansion mechanical tests. It is intended to make the adhesive layer have sufficient anti-slip ability in the direction parallel to the adhesive surface, while retaining a moderate degree of flexibility and buffer in the direction perpendicular to the adhesive surface, thereby effectively releasing the local stress generated by the expansion of the cell 11.

[0067] The first fastener 211 has a first binding force F when the cell assembly 1 is in the first state. 10 The first fastener 211 has a second binding force F when the cell assembly 1 is in the second state. 11 The first fastener 211 has a third binding force F when the cell assembly 1 is in the third state. 12 The second fastener 212 has a fourth binding force F when the cell assembly 1 is in the first state. 20 The second fastener 212 has a fifth binding force F when the cell assembly 1 is in the second state. 21 The second fastener 212 has a sixth binding force F when the cell assembly 1 is in the third state. 22 .

[0068] In this invention, the aforementioned "first binding force" and "fourth binding force" refer to the initial assembly tension applied by the first fastener 211 and the second fastener 212 after binding the battery cell assembly 1, and the initial force of pre-compression binding formed between the first fastener 211 and the battery cell assembly 1 and the frame 22. This force is the first binding force. The initial force of pre-compression binding formed between the second fastener 212 and the battery cell assembly 1 and the frame 22 is the second binding force. The aforementioned forces always exist during subsequent charging and discharging changes and the expansion and contraction of the battery cell 11, but the magnitude of the force changes dynamically with the deformation of the battery cell 11.

[0069] In this application, the binding force of the first fastener 211 under different states is tested using the following method: The length of the first fastener 211 under different states is measured using tools such as a laser displacement sensor and a mechanical measuring ruler. A steel strip of the same specification is then taken and placed in a tensile testing machine. The steel strip is stretched at a tensile speed of 50 mm / min until it reaches the same elongation as the first fastener 211 under different states. The tensile force value recorded by the tensile testing machine is the binding force of the first fastener 211 under the corresponding state. The binding force of the second fastener 212 is tested using the same method.

[0070] In some embodiments, the first fastener 211 is released from the first binding force F 10 Increase to the second binding force F 11 The growth rate is W 11 The second fastener 212 is subjected to the fourth binding force F 20 Increase to the fifth binding force F 21 The growth rate is W 21 W 11 ≥2W 21 , specifically, W 11 It can be 2 W 11 2.5 W 11 3 W 11 3.5 W 11 4 W 11 4.5 W 11 5 W 11 5.5 W 11 6 W 11 6.5 W 11 7W 11 Or any value within the range formed by any two of the above values.

[0071] Control W 11 ≥2W 21 This indicates that during the initial and middle stages of use of the battery device 100, as the cell assembly 1 transitions from the first state to the second state, the preload of the first fastener 211 increases significantly, and the difference in the preload growth rates between the first fastener 211 and the second fastener 212 is substantial. The first fastener 211 effectively constrains the expansion of the top of the cell 11, while the forces on the first fastener 211 and the second fastener 212 are relatively balanced, achieving a balance between controllable cell expansion and structural stability, thereby improving the safety and lifespan of the battery device. Optionally, 4W... 21 ≥W 11 ≥2W 21 .

[0072] It should be noted that the growth rate W 11 =(F 11 -F10 ) / F 10 100%, growth rate W 11 Used to measure the drastic change in the binding force of the first fastener 211. Correspondingly, the growth rate W 21 =(F 21 -F 20 ) / F 20 100%.

[0073] In some embodiments, the first fastener 211 is subjected to a second binding force F 11 Increase to the third binding force F 12 The growth rate is W 12 The second fastener 212 is subjected to the fifth binding force F. 21 Increase to the sixth binding force F 22 The growth rate is W 22 W 22 <W 12 ≤1.8W 22 . Specifically, W 12 It can be 1.1 W 22 1.2W 22 1.3W 22 1.4W 22 1.5W 22 1.6 W 22 1.7W 22 1.8 W 22 Or any value within the range formed by any two of the above values.

[0074] Control W 22 <W 12 ≤1.8 W 22 This indicates that during the later stages of use of the battery device 100, as the cell assembly 1 transitions from the second state to the third state, the growth rate of the pre-tightening force of the first fastener 211 is greater than that of the second fastener 212, and the difference between the growth rates of the pre-tightening forces of the first fastener 211 and the second fastener 212 is small. Both the first fastener 211 and the second fastener 212 have a good binding effect on the cell 11. The first fastener 211 can control the expansion of the top of the cell 11, and under the synergistic binding effect of the adhesive layer, the forces on the first fastener 211 and the second fastener 212 are balanced, which is beneficial to improving the overall structural stability of the cell 11 module, thereby improving the safety and service life of the battery device.

[0075] The first fastener 211 has a first length L when the cell assembly 1 is in the first state. 10 The first fastener 211 has a second length L when the cell assembly 1 is in the second state.11 The first fastener 211 has a third length L when the cell assembly 1 is in the third state. 12 The second fastener 212 has a fourth length L when the cell assembly 1 is in the first state. 20 The second fastener 212 has a fifth length L when the cell assembly 1 is in the second state. 21 The second fastener 212 has a sixth length L when the cell assembly 1 is in the third state. 22 .

[0076] In this application, tools such as laser displacement sensors and mechanical measuring rulers can be used to measure the lengths of the first fastener 211 and the second fastener 212 in different states.

[0077] In some embodiments, the first fastener 211 extends from the first length L 10 Increase to the second length L 11 The growth rate is D 11 The second fastener 212 extends from the fourth length L 20 Increased to the fifth length L 21 The growth rate is D 21 , 0 < D 11 -D 21 ≤0.3. Specifically, D 11 -D 21 It can be any value within the range of 0.01, 0.05, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, or any two of the above values.

[0078] Control 0 < D 11 -D 21 ≤0.3 indicates that during the initial and middle stages of use of the battery device 100, as the cell assembly 1 transitions from the first state to the second state, the difference in the length growth rate of the first fastener 211 and the second fastener 212 is not significant. During the expansion of the cell assembly 1, the first fastener 211 and the second fastener 212 can deform synchronously, avoiding stress transmission imbalance caused by excessive difference in length growth rate. This makes the shear stress distribution on the contact surface between the adhesive layer and the cell 11 and the frame 22 more uniform, significantly reducing the risk of local stress concentration and improving the overall structural stability of the battery device 100.

[0079] It should be noted that the growth rate D 11 =(L 11 -L 10 ) / L 10 100%, growth rate D 11 Used to measure the degree of length variation of the first fastener 211. Correspondingly, the growth rate D... 21 =(L 21- L 20 ) / L 20 100%.

[0080] In some embodiments, L 11 -L 10 =0.7cm~1.5cm, specifically, L 11 -L 10 The value can be any value within the range of 0.7cm, 0.8cm, 0.9cm, 1.0cm, 1.1cm, 1.2cm, 1.3cm, 1.4cm, 1.5cm, or any two of the above values. Control L 11 -L 10 Within the aforementioned range, it is indicated that in the initial stage of the cycle of the battery device 100, the length change of the first fastener 211 is small, and the first fastener 211 can effectively control the expansion of the top of the cell 11, which is beneficial to improving the overall structural stability of the cell 11 module.

[0081] In some embodiments, the first fastener 211 extends from the second length L 11 Increase to the third length L 12 The growth rate is D 12 The second fastener 212 extends from the fifth length L 21 Increased to the sixth length L 22 The growth rate is denoted as D 22 , 0 < D 12 -D 22 ≤0.5, specifically, D 21 -D 22 It can be any value within the range of 0.01, 0.05, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or any two of the above values.

[0082] Control 0 < D 12 -D 22 ≤0.5 indicates that during the middle and later stages of use of the battery device 100, in the process of the cell assembly 1 changing from the second charge state to the third charge state, the difference in the length growth rate of the first fastener 211 and the second fastener 212 is small. The first fastener 211 can effectively control the expansion of the top of the cell 11, which is beneficial to improving the overall structural stability and service life of the cell 11 module.

[0083] In some embodiments, when the battery cell assembly 1 is at a battery health level of 65% to 75%, the first fastener 211 bears a tension of 60,000 N to 130,000 N generated by the expansion of the battery cell assembly 1. Specifically, it can be any value within the range of 60,000 N, 65,000 N, 70,000 N, 75,000 N, 80,000 N, 85,000 N, 90,000 N, 95,000 N, 100,000 N, 110,000 N, 120,000 N, 130,000 N, or any two of the above values. Within the above range, it is beneficial to control the expansion deformation of the battery cell assembly 1 and prevent the battery cell assembly 1 from becoming loose or overloaded.

[0084] It should be noted that battery health (State of Health, SOH) is a percentage indicator that measures the battery's current performance compared to its brand-new condition at the time of manufacture. Specifically, it is the ratio of the battery's current fully charged energy (or capacity) to its rated nominal capacity (or energy) at the time of manufacture. When cell assembly 1 is at 70% battery health, it means that the battery can currently store and release only 70% of the amount of electricity it had in its brand-new state.

[0085] In some embodiments, when the cell assembly 1 is at 60% battery health, the first fastener 211 is subjected to a tension of less than or equal to 130,000 N generated by the expansion of the cell assembly 1.

[0086] In some embodiments, when the cell assembly 1 is at 65% battery health, the first fastener 211 is subjected to a tension of less than or equal to 105000N generated by the expansion of the cell assembly 1.

[0087] In some embodiments, when the cell assembly 1 is at 70% battery health, the first fastener 211 is subjected to a tension of less than or equal to 80,000 N generated by the expansion of the cell assembly 1.

[0088] In some embodiments, continue as follows Figure 1 As shown, the housing assembly 2 also includes an end plate 23. The end plate 23 is disposed at both ends of the cell assembly 1 to clamp all the cells 11. The end plate 23 is disposed in the area enclosed by the first fastener 211 and the second fastener 212. That is, the first fastener 211 and the second fastener 212 surround the end plate 23 and the multiple cells 11 to bind them together to form a stable module as a whole.

[0089] Figure 4 This application provides a schematic diagram of the structure of an end plate according to an embodiment of the present application. Figure 1 and Figure 4As shown, the side of the end plate 23 away from the cell assembly 1 includes at least one first mounting groove 231 recessed towards the cell assembly 1 and at least one second mounting groove 232 recessed towards the cell assembly 1. A first fastener 211 is located within the first mounting groove 231, and a second fastener 212 is located within the second mounting groove 232. The arrangement of the first mounting groove 231 and the second mounting groove 232 facilitates the fixing of the positions of the first fastener 211 and the second fastener 212, reducing movement of the first fastener 211 and the second fastener 212 during operation.

[0090] In some embodiments, the length of the first mounting groove 231 along the second direction is 15mm to 50mm, specifically it can be 15mm, 18mm, 20mm, 23mm, 25mm, 28mm, 30mm, 35mm, 40mm, 45mm, 50mm or any value within the range of any two of the above values.

[0091] In some embodiments, the length of the second mounting groove 232 along the second direction is 15mm to 22mm, specifically it can be 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm or any value within the range of any two of the above values.

[0092] It should be noted that the width of the first mounting slot 231 is the width of the first fastener 211, and the width of the second mounting slot 232 is the width of the second fastener 212.

[0093] In some embodiments, Figure 5 This is another schematic diagram of the battery device provided in the embodiments of this application. Figure 6 for Figure 5 A magnified view of a portion of region I, as shown below. Figure 5 and Figure 6 As shown, the first fastener 211 and the second fastener 212 have a length direction and a width direction, with the length direction being parallel to the width direction. Figure 5 The direction of the X-axis is parallel to the width direction. Figure 5 The direction of the Y-axis in the diagram.

[0094] In the length direction, a first insulating sleeve 24 is fitted on the first fastener 211. The first insulating sleeve 24 covers the battery cell assembly 1 in the first direction (length direction) to isolate the first fastener 211 and the battery cell assembly 1, and to ensure the insulation between the multiple battery cells 11 in the battery cell assembly 1 and the first fastener 211.

[0095] In the length direction, a second insulating sleeve 25 is provided on the second fastener 212. The second insulating sleeve 25 covers the cell assembly 1 in the first direction (length direction) to isolate the second fastener 212 and the cell assembly 1, and to ensure the insulation of the multiple cells 11 in the cell assembly 1 and the second fastener 212.

[0096] In some embodiments, the first fastener 211 is formed by welding the ends of a long strip of stainless steel. One end and the other end of the first fastener 211 at least partially overlap to form a first overlapping portion. The depth of the first mounting groove 231 corresponding to the first overlapping portion is greater than the depth of at least a portion of the first mounting groove 231 that does not correspond to the first overlapping portion. This application, by differentiating the depth of the first mounting groove 231, makes the groove corresponding to the first overlapping portion deeper, providing greater accommodating space for the first fastener 211 and the first insulating sleeve 24. This helps to keep the surface of the end plate 23 facing away from the cell assembly flush, ensuring the overall flatness and compactness of the battery device 100.

[0097] In some embodiments, the second fastener 212 is formed by welding the ends of a long strip of stainless steel. One end and the other end of the second fastener 212 at least partially overlap to form a second overlapping portion. The depth of the second mounting groove 232 corresponding to the second overlapping portion is greater than the depth of at least a portion of the second mounting groove 232 that does not correspond to the second overlapping portion. This application, by differentiating the depth of the second mounting groove 232, makes the depth of the second mounting groove 232 corresponding to the second overlapping portion deeper, providing greater accommodating space for the second fastener 212 and the second insulating sleeve 25. This helps to keep the surface of the end plate 23 facing away from the cell assembly flush, ensuring the overall flatness and compactness of the battery device 100.

[0098] In one embodiment, at least a portion of the first overlapping portion is welded together to form a first welded portion. The first welded portion is fitted with a third insulating sleeve 26. The third insulating sleeve 26 is at least partially disposed between the first fastener 211 and the end plate 23, which can effectively prevent the leakage risk caused by the rusting of the first welded portion.

[0099] In one embodiment, the depth of the groove in the first mounting groove 231 corresponding to the third insulating sleeve 26 is greater than the depth of at least a portion of the grooves in the first mounting groove 231 that do not correspond to the third insulating sleeve 26. This application, by differentiating the groove depth of the first mounting groove 231, makes the groove in the first mounting groove 231 corresponding to the third insulating sleeve 26 deeper, providing greater accommodating space for the first fastener 211 and the third insulating sleeve 26. This helps to keep the surface of the end plate 23 facing away from the cell assembly flush, ensuring the overall flatness and compactness of the battery device 100.

[0100] In one embodiment, the depth of the groove in the first mounting groove 231 corresponding to the third insulating sleeve 26 is greater than the depth of at least a portion of the groove in the first mounting groove 231 corresponding to the first overlapping portion but not corresponding to the third insulating sleeve 26. This application differentiates the groove depth of the first mounting groove 231, making the groove in the first mounting groove 231 corresponding to the third insulating sleeve 26 the deepest. This provides ample embedded space for the third insulating sleeve 26, ensuring that the third insulating sleeve 26 is completely submerged within the first mounting groove 231. This avoids interference caused by the third insulating sleeve protruding above the side surface of the end plate 23 away from the cell assembly, and also utilizes the sidewall of the first mounting groove 231 to form a circumferential limit on the third insulating sleeve 26, enhancing the positional stability of the third insulating sleeve 26 under thermal expansion or pressure. The groove depth of the first mounting groove 231 corresponding to the first overlapping portion but not corresponding to the third insulating sleeve 26 is the next deepest, which facilitates effective contact between the first fastener 211 and the first mounting groove 231, while avoiding a decrease in the load-bearing capacity of the end plate 23 due to excessive grooving. The first mounting groove 231 has the shallowest depth, which is not the groove corresponding to the first overlapping part. This helps to maintain the rigidity of the end plate 23 and reduce the risk of local stress concentration.

[0101] In one embodiment, at least a portion of the second overlapping portion is welded together to form a second welded portion. The second welded portion is fitted with a fourth insulating sleeve 27. The fourth insulating sleeve 27 is at least partially disposed between the second fastener 212 and the end plate 23, which can effectively prevent the leakage risk caused by the rusting of the first welded portion.

[0102] In one embodiment, the depth of the second mounting groove 232 corresponding to the groove of the fourth insulating sleeve 27 is greater than the depth of at least a portion of the second mounting groove 232 corresponding to the second overlapping portion and not corresponding to the fourth insulating sleeve 27. This application, by differentiating the groove depth of the second mounting groove 232, makes the groove of the second mounting groove 232 corresponding to the fourth insulating sleeve 27 deeper, providing greater accommodating space for the second fastener 212 and the fourth insulating sleeve 27. This helps to keep the surface of the end plate 23 facing away from the cell assembly flush, ensuring the overall flatness and compactness of the battery device 100.

[0103] In one embodiment, the depth of the second mounting groove 232 corresponding to the groove of the fourth insulating sleeve 27 is greater than the depth of at least a portion of the second mounting groove 232 corresponding to the second overlapping portion but not corresponding to the fourth insulating sleeve 27. This application differentiates the groove depth of the second mounting groove 232, making the groove of the second mounting groove 232 corresponding to the fourth insulating sleeve 27 the deepest. This provides ample embedded space for the fourth insulating sleeve 27, ensuring that the fourth insulating sleeve 27 is completely submerged within the second mounting groove 232. This avoids interference caused by the fourth insulating sleeve 27 protruding above the side surface of the end plate 23 away from the cell assembly, and also utilizes the sidewall of the second mounting groove 232 to form a circumferential limit on the fourth insulating sleeve 27, enhancing the positional stability of the fourth insulating sleeve 27 under thermal expansion or pressure. The groove depth of the second mounting groove 232 corresponding to the first overlapping portion but not corresponding to the fourth insulating sleeve 27 is the next deepest, which facilitates effective contact between the second fastener 212 and the second mounting groove 232, while avoiding a decrease in the load-bearing capacity of the end plate 23 due to excessive slotting. The second mounting groove 232 has the shallowest depth, which is not the groove corresponding to the first overlapping part. This helps to maintain the rigidity of the end plate 23 and reduce the risk of local stress concentration.

[0104] In some embodiments, the first insulating sleeve 24, the second insulating sleeve 25, the third insulating sleeve 26 and the fourth insulating sleeve 27 are all tubular structures made of materials such as polyvinyl fluoride (PVF), polyolefin (PO), fluoropolymer (FP) and synthetic rubber (SR), with a thickness of 0.5 mm to 10 mm.

[0105] In some embodiments, the lengths of the third insulating sleeve 26 and the fourth insulating sleeve 27 are adaptively adjusted according to the first welding portion and the second welding portion. For example, the lengths of the third insulating sleeve 26 and the fourth insulating sleeve 27 are both 30mm to 200mm, and the thicknesses of the third insulating sleeve 26 and the fourth insulating sleeve 27 are both 0.5mm to 1.0mm.

[0106] In some embodiments, the height difference in the first direction of the surface of the end plate 23 facing away from the cell assembly 1 is less than or equal to 3 mm, specifically it can be 0 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or any value within the range of any two of the above values. The surface of the end plate 23 facing away from the cell assembly 1 has superior surface flatness, which can ensure that a uniform surface contact is formed between the end plate 23 and the fastener 21, thereby improving the uniformity of the binding force transmission and the structural stability.

[0107] In some embodiments, Figure 7 Another structural schematic diagram of the end plate provided in the embodiments of this application is shown below, as follows: Figure 1 and Figure 7 As shown, the side surface of the end plate 23 facing the cell assembly 1 includes a central region 23A and an edge region 23B located around the central region 23A. The side surface of the end plate 23 facing the cell assembly 1 has a recessed structure 233 that is recessed in the direction of the cell assembly 1. The recessed structure 233 is located in the central region 23A. In this way, the end plate 23 can reserve a certain space for buffering the expansion of the cell 11.

[0108] In some embodiments, the end plate 23 is an integral structure formed by stamping or molding. The end plate 23 has an integral recessed structure 233 located in the central region 23A of the end plate 23 and recessed relative to the edge region 23B of the end plate 23. This embodiment forms the recessed structure 233 directly in the center of the end plate 23 through an integral molding process, resulting in a simple structure and high strength.

[0109] In some embodiments, the end plate 23 is a flat structure and does not have a recessed structure 233. The recessed structure 233 is formed by an adhesive member disposed on one side of the end plate 23 and the end plate 23 together. Specifically, the edge region 23B of the end plate 23 is provided with a groove, and the adhesive member is provided in the groove. The adhesive member surrounds and forms the recessed structure 233, and the end plate 23 is bonded to the battery cell 11 through the adhesive member.

[0110] In some embodiments, the adhesive can be a layered structure of a specific shape formed by an adhesive, or it can be a double-sided tape of a specific shape. One side of the adhesive is bonded to the end plate 23 to form a recessed structure 233, and the other side of the adhesive is bonded to the battery cell 11.

[0111] This application also provides an energy storage device that uses a battery as a power source. The energy storage device includes, but is not limited to, energy storage containers, energy storage cabinets, energy storage power stations, energy storage battery packs, or portable energy storage systems.

[0112] This application provides an electrical device that uses a battery as a power source. The electrical device includes, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0113] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A battery device, characterized in that, The battery device includes: A battery cell assembly, the battery cell assembly comprising a plurality of battery cells arranged along a first direction, the battery cells comprising an upper surface and a lower surface disposed opposite to each other; A housing assembly, the housing assembly including fasteners, the fasteners including at least one first fastener and at least one second fastener, the first fastener being located between the upper surface and the second fastener, the first fastener and the second fastener both surrounding the cell assembly in the circumferential direction. The length of the first fastener along the second direction is greater than the length of the second fastener along the second direction. The second direction is perpendicular to the first direction. The sum of the lengths of the first fastener along the second direction and the lengths of the second fastener along the second direction is L. The length of the battery cell assembly along the second direction is denoted as H. L≤1 / 3H.

2. The battery device according to claim 1, characterized in that, At least some of the adjacent cells are provided with an elastic structure.

3. The battery device according to claim 2, characterized in that, The elastic structure comprises polypropylene material; and / or the thermal conductivity of the elastic structure is 0.020 W / m / K to 0.080 W / m / K.

4. The battery device according to claim 2, characterized in that, The compressive force of the elastic structure under a compression deformation of 20% to 40% is F1, in N. When the battery cell assembly is fully charged, the first fastener has a binding force F2, in N, and F1 / F2 = 0.5 to 1.

5.

5. The battery device according to claim 1, characterized in that, The housing assembly also includes an adhesive layer and a frame, with the plurality of battery cells fixed to the frame via the adhesive layer; When the ratio of the length of the first fastener along the second direction to the length of the second fastener along the second direction is greater than or equal to 1.5, the shear strength at the interface between the adhesive layer and the plurality of battery cells and the frame is T, in N / mm². 2 The peel strength of the adhesive layer at the point where it is attached to the plurality of battery cells and the frame is P, in N / mm, and T / P≥3.

6. The battery device according to claim 1, characterized in that, The first fastener has a first binding force F when the cell assembly is in the first state. 10 The first fastener has a second binding force F when the cell assembly is in the second state. 11 The second fastener has a fourth binding force F when the cell assembly is in the first state. 20 The second fastener has a fifth binding force F when the cell assembly is in the second state. 21 The first state is the state corresponding to when the number of cycles of the battery cell assembly is the first number of cycles, and the second state is the state corresponding to when the number of cycles of the battery cell assembly is the second number of cycles, wherein the second number of cycles is greater than the first number of cycles. The first fastener is subjected to the first binding force F 10 Increase to the second binding force F 11 The growth rate is W 11 The second fastener is subjected to the fourth binding force F 20 Increase to the fifth binding force F 21 The growth rate is W 21 W 11 ≥2W 21 .

7. The battery device according to claim 6, characterized in that, The first fastener has a third binding force F when the cell assembly is in the third state. 12 The second fastener has a sixth binding force F when the cell assembly is in the third state. 22 The third state is the state corresponding to the number of cycles of the battery cell assembly being the third number of cycles, wherein the third number of cycles is greater than the second number of cycles; The first fastener is subjected to the second binding force F 11 Increase to the third binding force F 12 The growth rate is W 12 The second fastener is subjected to the fifth binding force F 21 Increase to the sixth binding force F 22 The growth rate is W 22 W 22 <W 12 ≤1.8W 22 .

8. The battery device according to claim 1, characterized in that, The first fastener has a first length L when the cell assembly is in the first state. 10 The first fastener has a second length L when the cell assembly is in the second state. 11 The second fastener has a fourth length L when the cell assembly is in the first state. 20 The second fastener has a fifth length L when the cell assembly is in the second state. 21 The first state is the state corresponding to when the number of cycles of the battery cell assembly is the first number of cycles, and the second state is the state corresponding to when the number of cycles of the battery cell assembly is the second number of cycles, wherein the second number of cycles is greater than the first number of cycles. The first fastener extends from the first length L 10 Increase to the second length L 11 The growth rate is D 11 The second fastener extends from the fourth length L 20 Increased to the fifth length L 21 The growth rate is D 21 , 0 < D 11 -D 21 ≤0.

3.

9. The battery device according to claim 8, characterized in that, The first fastener has a third length L when the cell assembly is in the third state. 12 The second fastener has a sixth length L when the cell assembly is in the third state. 22 The third state is the state corresponding to the number of cycles of the battery cell assembly being the third number of cycles, wherein the third number of cycles is greater than the second number of cycles; The first fastener extends from the second length L 11 Increase to the third length L 12 The growth rate is D 12 The second fastener extends from the fifth length L 21 Increased to the sixth length L 22 The growth rate is denoted as D 22 , 0 < D 21 -D 22 ≤0.

5.

10. The battery device according to claim 8, characterized in that, L 11 -L 10 =0.7cm~1.5cm 11. The battery device according to claim 7 or 9, characterized in that, The first cycle number is (0~1 / 2). N, where the number of the second cycle is (1 / 2 to 2 / 3). N, where the number of the third cycle is (2 / 3~1). N, where N is the total number of cycles of the battery cell assembly, N=8000~15000.

12. The battery device according to claim 1, characterized in that, When the battery cell assembly is at a battery health level of 65% to 75%, the first fastener bears a tension of 60,000 N to 130,000 N caused by the expansion of the battery cell assembly.

13. The battery device according to claim 1, characterized in that, The first fastener is at least partially fitted with a first insulating sleeve, which covers the cell assembly in the first direction; and / or, the second fastener is at least partially fitted with a second insulating sleeve, which covers the cell assembly in the first direction.

14. The battery device according to claim 1, characterized in that, The housing assembly further includes end plates, which are disposed at both ends of the cell assembly and within the area enclosed by the first fastener and the second fastener; The side of the end plate away from the cell assembly includes at least one first mounting groove recessed toward the cell assembly and at least one second mounting groove recessed toward the cell assembly, wherein the first fastener is at least partially located in the first mounting groove and the second fastener is at least partially located in the second mounting groove.

15. The battery device according to claim 14, characterized in that, The length of the first mounting groove along the second direction is 15mm to 50mm, and the length of the second mounting groove along the second direction is 15mm to 22mm.

16. The battery device according to claim 14, characterized in that, One end of the first fastener overlaps at least partially with the other end to form a first overlapping portion, and the depth of the first mounting groove corresponding to the groove of the first overlapping portion is greater than the depth of at least a portion of the groove of the first mounting groove that does not correspond to the first overlapping portion; and / or, one end of the second fastener overlaps at least partially with the other end to form a second overlapping portion, and the depth of the second mounting groove corresponding to the groove of the second overlapping portion is greater than the depth of at least a portion of the groove of the second mounting groove that does not correspond to the second overlapping portion.

17. The battery device according to claim 16, characterized in that, At least a portion of the first overlapping portion is welded together to form a first welded portion, the first welded portion being fitted with a third insulating sleeve, the third insulating sleeve being at least partially disposed between the first fastener and the end plate; and / or, at least a portion of the second overlapping portion is welded together to form a second welded portion, the second welded portion being fitted with a fourth insulating sleeve, the fourth insulating sleeve being at least partially disposed between the second fastener and the end plate.

18. The battery device according to claim 17, characterized in that, The depth of the groove corresponding to the third insulating sleeve in the first mounting groove is greater than the depth of at least a portion of the grooves in the first mounting groove that do not correspond to the third insulating sleeve; and / or, The depth of the second mounting groove corresponding to the groove of the fourth insulating sleeve is greater than the depth of at least a portion of the grooves of the second mounting groove that do not correspond to the fourth insulating sleeve.

19. The battery device according to claim 17, characterized in that, The depth of the groove corresponding to the third insulating sleeve in the first mounting groove is greater than the depth of at least a portion of the groove corresponding to the first overlapping portion but not to the third insulating sleeve; and / or, The depth of the second mounting groove corresponding to the groove of the fourth insulating sleeve is greater than the depth of at least a portion of the second mounting groove corresponding to the second overlapping portion and not corresponding to the fourth insulating sleeve.

20. The battery device according to claim 14, characterized in that, The height difference between the surface of the end plate on the side opposite to the cell assembly in the first direction is less than or equal to 3 mm.

21. The battery device according to claim 14, characterized in that, The end plate has a central region and an edge region located around the central region on one side of the surface facing the battery cell assembly. The end plate has a recessed structure that is recessed toward the battery cell assembly and the recessed structure is located within the central region.

22. The battery device according to claim 21, characterized in that, The edge region of the end plate is provided with a groove, and an adhesive is provided in the groove, the adhesive surrounding the recessed structure.

23. An energy storage device, characterized in that, The energy storage device includes the battery device according to any one of claims 1 to 22, the battery device being used to store electrical energy.

24. An electrical appliance, characterized in that, The electrical device includes the battery device according to any one of claims 1 to 22, the battery device being used to provide electrical energy.

Images