A safety verification method for clamping battery cell modules into a box

Abstract

This invention provides a safety verification method for clamping battery cell modules into a box. The safety verification method includes the following steps: Step 1, determining the clamping force F of the clamp. 夹 A static friction test bench was built, and the static friction between the urethane block and the blue film was tested and analyzed on the test bench to determine the clamping force F of the fixture. 夹 Step 2: Determine the cumulative relative displacement ΔL of the battery cells in the module in the Z direction. 总 This safety verification method determines the minimum reliable clamping force in the Y direction by studying the static friction coefficient of the clamp on the side of the module; and determines the maximum cumulative relative displacement of the battery cell in the Z direction by studying the deformation curve of the relationship between ΔLmax and τ of the double-sided adhesive foam. This provides data support for the design of the module clamping and boxing tooling, ensuring the reliability of the clamp for module handling when the battery cell module is clamped and boxed.

Description

Technical Field

[0001] This invention relates to the field of battery pack technology, and in particular to a safety verification method for clamping battery cell modules into a box. Background Technology

[0002] In the existing CTP battery pack cell module (hereinafter referred to as module) extrusion into the box process, such as Figure 1 As shown, the cells are compressed to the specified box size along the length (X direction) of the stack. Then, the module is transported as a whole using two methods: one is to use a suction cup to pick up the top of the cells for transport, and the other is to clamp the cells in the center along the width (Y direction) for transport.

[0003] When using a suction-and-handle method, firstly, due to the significant differences in size and structure between the cell modules of different battery packs, it is difficult to ensure that the vacuum port and the top cover position of each cell are matched one-to-one when using the same suction cup, resulting in poor compatibility; secondly, vacuum suction cups are expensive, and spare parts need to be replaced frequently during use, leading to high long-term investment; finally, these suction cups are usually custom-made and outsourced parts, with long procurement cycles, making them unsuitable for short-term changeover production needs. Therefore, in actual production, suction cup suction-and-handle methods are mostly used in mass production lines.

[0004] In existing technologies, the extrusion of CTP battery pack cell modules into the box mostly involves clamping and handling. When the load weight is large (such as large multi-row modules weighing more than 100~300kgf), determining the appropriate clamping force in the Y-axis of the clamp to ensure reliable handling becomes a technical challenge. For modules formed by bonding cells with double-sided adhesive foam, it is crucial to ensure proper gripping while preventing significant deflection deformation. Figure 2 As shown, when clamping an elastic body load and a rigid body load, the deformation of the elastic body load is significantly greater than that of the rigid body load.

[0005] For the reasons mentioned above, a safety verification method for clamping battery cell modules into a box is needed, which studies the magnitude of the clamping force required by the clamp and the maximum cumulative relative displacement of the battery cells in the Z direction within multiple rows of modules. Summary of the Invention

[0006] The purpose of this invention is to provide a safety verification method for clamping battery cell modules into a box. This safety verification method verifies whether the battery cell module can be safely clamped into the box by studying the magnitude of the clamping force required by the fixture and the cumulative relative displacement of the battery cell in the Z direction within the module. It can also serve as a theoretical premise and data support for the design of battery cell module fixtures.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A safety verification method for clamping a battery cell module into a box, wherein the module includes multiple battery cells arranged sequentially along the length of the module, the sides of two adjacent battery cells are bonded together by double-sided adhesive foam, and blue film is pasted on both sides of the module in the width direction. The clamp contacts and clamps the blue film through urethane blocks.

[0009] The security verification method includes the following steps:

[0010] Step 1, determine the clamping force of the fixture. F 夹 A static friction test bench was built, and the static friction between the urethane block and the blue film was tested and analyzed on the test bench to determine the clamping force of the fixture. F 夹 ;

[0011] Step 2: Determine the cumulative relative displacement of the cells in the module in the Z direction. ΔL 总 .

[0012] Furthermore, in the above-mentioned safety verification method for clamping the battery cell module into the box, in step 1, the experimental platform includes a ramp and an adjusting rod. One end of the ramp is hinged to the ground, and the other end is supported by the adjusting rod. A handwheel is provided at the upper end of the adjusting rod. Rotating the handwheel can adjust the height of the adjusting rod, thereby adjusting the tilt angle θ of the ramp. The ramp is covered with a blue film.

[0013] Furthermore, in the above-mentioned safety verification method for clamping the battery cell module into the box, step 1 specifically includes:

[0014] Step 11: After the experimental platform is set up, place the urethane block on the blue film, rotate the handwheel to slowly raise the ramp, adjust the inclination angle θ of the ramp, and stop rotating the handwheel at the moment when the urethane block is about to slide down the blue film, and record the angle θ of the ramp from horizontal to this moment.

[0015] At this moment, the forces acting on the urethane block include:

[0016] gravity G and friction F f ,

[0017] gravity G Decomposed into downward force F s The force pressing against the inclined plane, and the supporting force. F n For action and reaction forces,

[0018] static friction coefficient f s ,

[0019] F f = F s ,

[0020] Gcosθ*f s = Gsinθ ,

[0021] f s = tanθ

[0022] Step 12: During the process of transferring the fixture module, the frictional force generated by the fixture holding the module needs to overcome the module's own weight G. 模块 ,

[0023] The minimum reliable clamping force F 夹 It should meet the following requirements: F 夹 ≥K *f s * G 模块 Where K is the safety factor, which is 2-3.

[0024] Furthermore, in the aforementioned safety verification method for clamping and placing the battery cell module into the box, in step 2, the module's length direction is the X-axis, width direction is the Y-axis, and height direction is the Z-axis. During the process of transferring the module by the clamp, the cumulative relative displacement of the module's battery cell in the Z-axis is ΔL. 总 The shear deformation of a single foam is ΔL n Where n is the number of cell rows, and the cumulative relative displacement ΔL 总 It is formed by the cumulative deformation of all double-sided adhesive foam within the module under shear force. When the clamp holds the cell, the static equilibrium force on the side of the cell is the shear force τ, which is generated from both ends of the module to the center by the weight G of one cell. 电芯 The shear force decreases gradually, with the maximum shear force at both ends of the module, τmax = (n-2) * 0.5G 电芯 When the number of cell rows n of the module clamped in the Y direction is greater than 3, the cumulative relative displacement ΔL generated by the module in the Z direction is... 总 for:

[0025] ΔL 总 =max{ΔL1+ΔL2+ΔL3+…+ΔL n / 2}

[0026] Then the minimum reliable cumulative relative displacement ΔL 总It should be less than 1 / 500 of the module's length in the clamping direction.

[0027] Furthermore, in the aforementioned safety verification method for clamping the battery cell module into the box, the double-sided adhesive foam is made of microporous foamed polypropylene with a thickness of 23.5 mm, a width of 25 mm, a tensile strength ≥ 3 MPa, and a shear strength ≥ 2 MPa. The double-sided adhesive foam has a compression rate ≤ 10% under 300 kPa pressure, an adhesive layer shear strength ≥ 1.5 MPa, and a 180° peel force > 10 N / 25 mm.

[0028] Analysis reveals that this invention discloses a safety verification method for clamping and placing battery cell modules into a box. This method determines the minimum reliable clamping force in the Y direction by studying the static friction coefficient (static friction coefficient between the urethane block and the blue film) of the clamp on the side extrusion surface of the module; and determines the maximum cumulative relative displacement of the battery cell in the Z direction by studying the dynamic shear force-deformation curve of the double-sided adhesive foam and analyzing the shear force on the double-sided adhesive foam. This provides data support for the design of the module clamping and boxing tooling, ensuring the reliability of the clamp for module handling when clamping and placing the battery cell module into the box. Attached Figure Description

[0029] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0030] Figure 1 A three-dimensional structural diagram illustrating the use of clamps to hoist and hold battery cell modules.

[0031] Figure 2 This is a comparison chart of deformation trends under elastic body load and rigid body load.

[0032] Figure 3 This is a schematic diagram of the static friction coefficient measurement experiment according to an embodiment of the present invention.

[0033] Figure 4 This is a diagram showing the force analysis of the module's side clamping and static equilibrium.

[0034] Figure 5 This is a curve showing the relationship between ΔLmax and τ for double-sided adhesive foam material measured on a universal testing machine.

[0035] Figure 6 This is a schematic diagram of the cumulative relative displacement of a module composed of multiple rows of battery cells. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. Indeed, those skilled in the art will recognize that modifications and variations can be made to the invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the invention encompass such modifications and variations falling within the scope of the appended claims and their equivalents.

[0037] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected," "linked," and "set up" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0038] The accompanying drawings illustrate one or more examples of the invention. The detailed description uses numerals and letters to refer to features in the drawings. Similar or analogous reference numerals in the drawings and description have been used to refer to similar or analogous parts of the invention. As used herein, the terms “first,” “second,” and “third,” etc., are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0039] like Figures 3 to 6As shown in the figure, according to an embodiment of the present invention, a safety verification method for clamping a battery cell module into a box is provided. The module includes multiple battery cells arranged sequentially along the length of the module. The sides of adjacent battery cells are bonded together by double-sided adhesive foam. Blue films are attached to both sides of the module in the width direction. The clamp contacts the blue films through urethane blocks and clamps them in a centered manner. The urethane blocks are polyurethane rubber blocks (yellow in the figure) with a Shore hardness of A70-85. The function of the urethane blocks is to increase the coefficient of friction of the contact surface, provide soft contact compression, and provide insulation. The double-sided adhesive-backed foam (item number DST-05) is made of microporous foamed polypropylene (MPP), with a thickness of 23.5mm, a width of 25mm, a tensile strength ≥3MPa, a shear strength ≥2MPa, a compression ratio ≤10% under 300kPa pressure, an adhesive layer shear strength ≥1.5MPa, a 180° peel force >10N / 25mm, a thermal conductivity ≤0.05W / m*K, an insulation resistance of 500MΩ (1000VDC, relative humidity ≤90%), an insulation withstand voltage of 2500VAC@50Hz@60s, and a leakage current ≤1mA without damage. The flame retardant properties of the double-sided adhesive-backed foam meet the UL94 HF-1 standard, and the long-term operating temperature is -40℃ to 85℃.

[0040] This safety verification method determines the minimum reliable clamping force in the length direction of the module by studying the static friction coefficient of the clamp on the side extrusion surface of the cell (the static friction coefficient between the urethane block and the blue film); and determines the maximum cumulative relative displacement of the cell in the height direction by studying the dynamic shear force-deformation curve of the double-sided adhesive foam and analyzing the shear force on the foam.

[0041] The security verification method includes the following steps:

[0042] Step 1, determine the clamping force of the fixture. F 夹 A static friction test bench was built, and the static friction between the urethane block and the blue film was tested and analyzed on the test bench to determine the clamping force of the fixture. F 夹 .

[0043] like Figure 3 As shown, the experimental platform includes a ramp and an adjusting rod. One end of the ramp is hinged to the ground, and the other end is supported by the adjusting rod. A handwheel is provided at the upper end of the adjusting rod. Rotating the handwheel can adjust the height of the adjusting rod, thereby adjusting the tilt angle θ of the ramp. The ramp is covered with a blue film.

[0044] Step 1 specifically includes:

[0045] Step 11: After the static friction test platform is set up, place the urethane block with the same material and performance as the clamp on the blue film. Rotate the handwheel to slowly raise the ramp plate and adjust the tilt angle θ of the ramp plate. Stop rotating the handwheel at the moment when the urethane block is about to slide down the blue film (the urethane block is in static equilibrium state) and record the angle θ of the ramp plate from horizontal to this moment.

[0046] At this moment, the forces acting on the urethane block include:

[0047] gravity G and friction F f ,

[0048] gravity G Decomposed into downward force F s and support F n ,

[0049] static friction coefficient f s ,

[0050] F f = F s ,

[0051] Gcosθ*f s = Gsinθ , f s = tanθ .

[0052] Step 12: During the process of transferring the fixture module, the frictional force generated by the fixture holding the module needs to overcome the module's own weight G. 模块 ,

[0053] The minimum reliable clamping force F 夹 It should meet the following requirements:

[0054] F 夹 ≥K *f s * G 模块 Where K is the safety factor, which is 2-3.

[0055] Explanation of K taking values ​​of 2-3: G = f s * G 模块 It is the minimum force required to maintain static balance or uniform motion in the direction of the load's gravity.

[0056] Motion state 1: When K=1, F 夹 =1*G, just enough to maintain static balance or uniform motion in the direction of the load's gravity;

[0057] Motion state 2: When K=2, F 夹 =2*G, even if 1 / 2 of F suddenly disappears (such as the lifting rope suddenly breaks or the screw suddenly loses its self-locking), the other 1 / 2 F can still ensure static balance or uniform motion in the direction of the load gravity.

[0058] Motion state (3): When K=3, F 夹 =3*G, based on 2, the load can reach a maximum speed of 1m / s. 2 The acceleration of the motion is greater than that of ordinary hoisting and handling, which will not exceed this value.

[0059] Step 2: Determine the cumulative relative displacement of the cells in the module in the Z direction. ΔL 总 .

[0060] The module's length is in the X-axis, width in the Y-axis, and height in the Z-axis. During the fixture transfer of the module, the cumulative relative displacement of the battery cells in the module in the Z-axis is ΔL. 总 The shear deformation of a single foam is ΔL n Where n is the number of cell rows, and the cumulative relative displacement ΔL 总 It is the cumulative deformation of all double-sided adhesive foam within the module caused by shear force. Considering that the form and position tolerances cannot be too large when the module is placed horizontally into the box, the foam shear deformation amount ΔL is... n The smaller the better. According to... Figure 4 Static equilibrium force analysis of the side of the battery cell held by the clamp shows that the static equilibrium force on the side of the module during clamping is: shear force τ from both ends of the module to the center, calculated as the weight of one battery cell (G). 电芯 (Indicates) decreasing, with the maximum shear force at both ends of the module, τmax=(n-2)*0.5G 电芯 .

[0061] Figure 5 This is the "ΔLmax vs. τ deformation curve" of DST-05 double-sided adhesive foam material measured on a universal testing machine.

[0062] Figure 5The deformation curves of double-sided adhesive foam material measured at seven points are disclosed, specifically point 1 (Plot1), point 2 (Plot2), point 3 (Plot3), point 4 (Plot4), point 5 (Plot5), point 6 (Plot6), and point 7 (Plot7).

[0063] The steps to determine ΔLmax are as follows:

[0064] Based on the stress analysis of the double-sided adhesive foam material, the shear force T = 12.3 N.

[0065] τmax is the Y-axis coordinate of the curve.

[0066] Based on the Y-axis coordinate, find the maximum horizontal coordinate of the deformation curves of the double-sided adhesive foam material measured at the 7 points on the horizontal axis, which is the maximum deformation ΔLmax.

[0067] In Example 1, the number of cells in the module is 3. According to the dynamic tensile force-deformation curve, when G=2.5kgf and n=3, τmax=12.3N. Only the middle cell produces calculable displacement. At this time, the foam shear deformation (relative displacement) ΔLmax≤0.25mm (the length of the module in the clamping direction (the sum of the widths of all cells, i.e., the distance between the two urethane blocks) is 634mm). After clamping, the cumulative relative displacement of the cells in the Z direction in the module does not affect the reliability of the clamping.

[0068] Example 2, as Figure 6 As shown, when the number of cell rows n>3 in the module clamped in the Y direction, the cumulative relative displacement ΔL generated by the module in the Z direction is... 总 for:

[0069] ΔL 总 =max{ΔL1+ΔL2+ΔL3+…+ΔL n / 2}

[0070] The maximum cumulative relative displacement ΔL 总 It should be less than 1 / 500 of the module's length in the clamping direction (the sum of the widths of all cells, i.e., the distance between the two urethane blocks). That is, in the module's clamping direction (the direction perpendicular to where the cells generate relative displacement), the maximum cumulative relative displacement ΔL of the cells within every 500mm of length. 总 It should be less than 1mm. If the module's length in the clamping direction reaches 1000mm, the maximum cumulative relative displacement ΔL 总 It should be less than 2mm.

[0071] In summary, only when the minimum reliable clamping force is simultaneously satisfied... F 夹 and minimum reliable cumulative relative displacement ΔL总 Only when the analysis conditions are met can the design of the module clamping and boxing tooling be reliable.

[0072] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0073] A safety verification method for clamping and placing battery cell modules into a box is disclosed. This method determines the minimum reliable clamping force in the Y direction by studying the static friction coefficient (static friction coefficient between the urethane block and the blue film) of the clamp on the side extrusion surface of the module. By studying the dynamic shear force-deformation curve of the double-sided adhesive foam and analyzing the shear force on the double-sided adhesive foam, the maximum cumulative relative displacement of the module in the Z direction is determined. This provides data support for the design of the module clamping and placing tooling, ensuring the reliability of the clamp for module handling when clamping and placing battery cell modules into the box.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 safety verification method for clamping a battery cell module into a box, characterized in that, The module includes multiple battery cells arranged sequentially along the length of the module. Adjacent battery cells are bonded together on their sides using double-sided adhesive foam. Blue film is adhered to both sides of the module in the width direction. A clamp uses urethane adhesive blocks to contact and center the blue film, securing it firmly. The security verification method includes the following steps: Step 1, determine the clamping force of the fixture. F 夹 , A static friction test bench was constructed, and the static friction between the urethane block and the blue film was experimentally analyzed on the test bench to determine the clamping force of the fixture. F 夹 ; Step 2: Determine the cumulative relative displacement of the cells in the module in the Z direction. ΔL 总 , In step 1, the experimental platform includes a ramp and an adjusting rod. One end of the ramp is hinged to the ground and the other end is supported by the adjusting rod. A handwheel is provided at the upper end of the adjusting rod. Rotating the handwheel can adjust the height of the adjusting rod, thereby adjusting the tilt angle θ of the ramp. The ramp is covered with a blue film. Step 1 specifically includes: Step 11: After the experimental platform is set up, place the urethane block on the blue membrane, rotate the handwheel to slowly raise the ramp, and adjust the inclination angle θ of the ramp. Stop rotating the handwheel at the instant the urethane block is about to slide downwards along the blue film, and record the angle θ at which the ramp plate rotates from horizontal to this moment; At this time, the forces acting on the urethane block include: gravity G and friction F f , gravity G Decomposed into downward force F s The force pressing against the inclined plane, and the supporting force. F n For action and reaction forces, static friction coefficient f s , F f = F s ， Gcosθ*f s = Gsinθ ， f s = tanθ Step 12: During the process of transferring the fixture module, the frictional force generated by the fixture holding the module needs to overcome the module's own weight G. 模块 , The minimum reliable clamping force F 夹 It should meet the following requirements: F 夹 ≥K *f s * G 模块 Where K is the safety factor, which is 2-3. In step 2, the length direction of the module is the X-axis, the width direction is the Y-axis, and the height direction is the Z-axis. During the clamp transfer process, the cumulative relative displacement of the battery cell in the Z direction within the module is ΔL. 总 The shear deformation of a single foam is ΔL n Where n is the number of cell rows, Cumulative relative displacement ΔL 总 It is formed by the cumulative deformation of all double-sided adhesive foam within the module due to shear force. When the clamp holds the battery cell, the static equilibrium force on the side of the cell is a shear force τ, which is applied from both ends of the module to the center by the weight G of one battery cell. 电芯 The shear force decreases gradually, with the maximum shear force at both ends of the module, τmax = (n-2) * 0.5G 电芯 , When the number of cell rows n>3 in the module clamped in the Y direction, the cumulative relative displacement ΔL generated by the module in the Z direction is... 总 for: ΔL 总 =max{ΔL1+ΔL2+ΔL3+…+ΔL n / 2 } Then the minimum reliable cumulative relative displacement ΔL 总 It should be less than 1 / 500 of the module's length in the clamping direction.

2. The safety verification method for clamping and inserting a battery cell module into a box according to claim 1, characterized in that, The double-sided adhesive-backed foam is made of microporous foamed polypropylene, with a thickness of 23.5 mm, a width of 25 mm, a tensile strength ≥3 MPa, and a shear strength ≥2 MPa. The double-sided adhesive foam has a compression rate of ≤10% under 300kPa pressure, an adhesive layer shear strength of ≥1.5MPa, and a 180° peel force of >10N / 25mm.

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