Battery pack upper and lower shell pressing method based on secondary activation

Abstract

The present invention relates to the field of battery pack preparation, and in particular to a method for pressing the upper and lower shells of a battery pack based on secondary activation, comprising: obtaining the area ratio of an effective activation area; determining an initial heating method, including a uniform traversal heating method and an accelerated traversal heating method; completing secondary activation of the glue coating; sequentially completing the pressing and pressure holding of the upper and lower shells of the battery pack; increasing the heat input power of the infrared heating device when it is determined that the pressing of the upper and lower shells does not meet the preset standard according to the uniform traversal heating method, or determining the reason why the pressing does not meet the preset standard based on the pressing characteristic area; determining that the pressing of the upper and lower shells does not meet the preset standard according to the accelerated traversal heating method, based on the bonding consistency characteristic value, the reason for not meeting the preset standard includes insufficient hot melt or substandard traversal acceleration; and eliminating adhesive stringing in battery packs whose upper and lower shells meet the preset standard. This improves the reliability of the pressing and bonding of the upper and lower shells of the battery pack.

Description

Technical Field

[0001] The present invention relates to the field of battery pack preparation, and in particular to a method for pressing upper and lower shells of a battery pack based on secondary activation. Background Art

[0002] With the rapid development of new energy vehicles and energy storage technologies, lithium-ion battery packs, as core energy carriers, face a significant impact on system safety performance due to their structural sealing and durability. During battery pack assembly, the quality of the lamination of the upper and lower shells is crucial for isolating the battery cells from the environment. Traditional adhesive lamination techniques present the following challenges: During conventional single-pass lamination, the adhesive curing process easily generates a gradient stress distribution, leading to microcracks at the shell edges; existing vacuum lamination equipment struggles to completely eliminate microbubbles in high-viscosity structural adhesives; and, due to CTE differences in the dissimilar shell materials, traditional thermal curing processes produce an interface displacement of 0.15-0.3mm.

[0003] Reactivated materials, activated by infrared light to form a closed-cell structure, exhibit high resilience and energy absorption, and are becoming a mainstream adhesive material. During the lamination process, pressure is applied through a precision mold to ensure that the reactivated adhesive adheres perfectly to the battery pack housing, eliminating interfacial gaps. During the pressure holding phase, constant pressure is applied to maintain material deformation, ensuring a stable mechanical fit between the adhesive and the housing. The creep properties of the material are also utilized to optimize interfacial stress distribution.

[0004] Since the liquid colloid applied once deforms during the curing process, the overall shape is inconsistent before the second activation. In addition, fluctuations are caused by factors such as electrical parameters and equipment aging on the production line. As a result, the stability of the colloid activation between the upper and lower shells of the battery pack is poor, which seriously affects the reliability of the pressing and bonding of the upper and lower shells of the battery pack. Summary of the Invention

[0005] To this end, the present invention provides a method for pressing the upper and lower shells of a battery pack based on secondary activation, so as to overcome the problem in the prior art that the stability of the colloid activation is poor due to fluctuations in activation parameters, which affects the reliability of the pressing and bonding of the upper and lower shells of the battery pack.

[0006] To achieve the above objectives, the present invention provides a method for pressing the upper and lower shells of a battery pack based on secondary activation, comprising:

[0007] Step S1, collecting an image of the adhesive coating surface of the battery pack lower shell to obtain the area ratio of the effective activation area;

[0008] Step S2, determining an initial heating mode based on a comparison between the effective activation area ratio and a preset ratio, wherein the initial heating mode includes a uniform traversal heating mode and an accelerated traversal heating mode;

[0009] Step S3: leaving a preset distance between the glue-coated surface of the lower shell and the surface to be bonded of the upper shell, and performing secondary activation of the glue using an infrared heating device according to the initial heating method;

[0010] Step S4, using a press to sequentially complete the pressing and pressure-maintaining of the upper and lower shells of the battery pack;

[0011] Step S5, in response to the random inspection of the uniform speed traversal heating method to obtain an average value of the interface bonding strength, and determining based on the average value of the interface bonding strength that the pressing of the upper and lower shells does not meet the preset standard, increasing the heat input power of the infrared heating device, or determining based on the pressing characteristic area that the reasons for the pressing not meeting the preset standard include a pressing speed not meeting the standard and a traversal speed not meeting the standard; the pressing characteristic area is the integral area of the pressing time-upper shell displacement curve;

[0012] Step S6, in response to the random inspection of the accelerated traversal heating method to obtain an average value of the interface bonding strength, and determining based on the average value of the interface bonding strength that the pressing of the upper and lower shells does not meet the preset standard, determining based on the bonding consistency characteristic value that the reasons for not meeting the preset standard include insufficient hot melt or substandard traversal acceleration; the bonding consistency characteristic value is the difference in interface bonding strength between the initial heating area and the final heating area of the adhesive coating surface;

[0013] Step S7, removing the adhesive wires of the battery pack where the upper and lower shells are pressed together to meet the preset standards.

[0014] Furthermore, in response to the effective activation area area ratio being less than a preset ratio, the initial heating method is determined to be an accelerated traversal heating method, and in response to the effective activation area area ratio being greater than or equal to a preset ratio, the initial heating method is determined to be a uniform traversal heating method.

[0015] Furthermore, the uniform traversal heating method is that the infrared heating device covers the glue-coated surface of the lower shell of the battery pack and heats from the head end to the tail end at a uniform speed along the long-range direction of the lower shell; the accelerated traversal heating method is that the infrared heating device covers the glue-coated surface of the lower shell of the battery pack and heats from the head end to the tail end along the long-range direction of the lower shell at a preset acceleration.

[0016] Furthermore, in step S5, when the average value of the interface bonding strength is less than the second preset strength threshold, it is determined that the pressing of the upper and lower shells does not meet the preset standard; when the average value of the interface bonding strength is greater than or equal to the first preset strength threshold and less than the second preset strength threshold, the reason why the pressing does not meet the preset standard is determined based on the pressing characteristic area; and when the average value of the interface bonding strength is less than the first preset strength threshold, the heat input power of the infrared heating device for the next batch of pressing is increased.

[0017] Furthermore, the increase in the heat input power of the infrared heating device is positively correlated to the difference between the first preset intensity threshold and the average value of the interface bonding strength.

[0018] Furthermore, when the pressing feature area is smaller than the preset feature area, it is determined that the reason for not meeting the preset standard is that the pressing speed does not meet the standard; and when the pressing feature area is greater than or equal to the preset feature area, it is determined that the reason for not meeting the preset standard is that the traversal speed does not meet the standard.

[0019] Furthermore, in response to the pressing speed not meeting the standard, the pressing speed of the upper and lower shells of the next batch of battery packs is reduced, and the reduction in the pressing speed of the upper and lower shells of the next batch of battery packs is positively correlated to the difference between the preset characteristic area and the pressing characteristic area; in response to the traversing speed not meeting the standard, the traversing speed of the upper and lower shells of the next batch of battery packs is reduced, and the reduction in the traversing speed of the upper and lower shells of the next batch of battery packs is positively correlated to the difference between the pressing characteristic area and the preset characteristic area.

[0020] Furthermore, in step S6, when the average value of the interface bonding strength is less than a second preset strength threshold, it is determined that the pressing of the upper and lower shells does not meet the preset standard.

[0021] Furthermore, in step S6, when the bonding consistency characteristic value is less than the preset consistency characteristic threshold, it is determined that the reason for not meeting the preset standard is insufficient hot melt, and when the bonding consistency characteristic value is greater than or equal to the preset consistency characteristic threshold, it is determined that the reason for not meeting the preset standard is that the traversal acceleration does not meet the standard.

[0022] Furthermore, in response to insufficient hot melt, the heat input power of the next batch of pressing is increased, and the increase in the heat input power is positively correlated with the difference between the preset consistency characteristic threshold and the bonding consistency characteristic value; in response to the traversal acceleration not meeting the standard, the preset acceleration of the next batch of pressing is reduced, and the decrease in the preset acceleration is positively correlated with the difference between the bonding consistency characteristic value and the preset consistency characteristic threshold.

[0023] Compared to existing technologies, this invention offers significant advantages: by real-time collection and comparison of the percentage of effectively activated areas, the system can accurately identify adhesive layer distribution defects (such as adhesive breaks and bubble coverage) and dynamically select either a uniform or accelerated heating mode. Compared to traditional fixed-parameter heating, this solution significantly reduces ineffective energy loss while ensuring high adhesive layer activation coverage and consistent heating.

[0024] Furthermore, the present invention realizes the phase change control of the adhesive melting-flowing-curing by combining the infrared heating strategy with a preset spacing and high-pressure gradient pressure maintenance.

[0025] Furthermore, the present invention introduces the pressing feature area integral analysis and the bonding consistency feature value comparison to construct a multi-dimensional quality evaluation system. The feedback mechanism of periodic monitoring, feedback analysis and self-optimization reduces the process defect rate and shortens the single process debugging cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of a method for pressing the upper and lower shells of a battery pack based on secondary activation according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the adhesive coating structure of the lower shell of the battery pack according to an embodiment of the present invention;

[0028] Figure 3 A flow chart for determining the initial heating method according to an embodiment of the present invention;

[0029] Figure 4 This is a flow chart for determining whether the pressing of the upper and lower shells meets the preset standard under the uniform traversal heating method according to an embodiment of the present invention;

[0030] Figure 5 This is a flow chart for determining whether the pressing of the upper and lower shells meets preset standards under the accelerated traversal heating mode according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0032] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0033] See also Figure 1-Figure 5 , which are respectively a flow chart of a method for pressing the upper and lower shells of a battery pack based on secondary activation according to an embodiment of the present invention; a schematic diagram of the structure of the glue-coated surface of the lower shell of a battery pack according to an embodiment of the present invention; a flow chart for determining an initial heating method according to an embodiment of the present invention; a flow chart for determining whether the pressing of the upper and lower shells meets the preset standards under a uniform traversal heating method according to an embodiment of the present invention; and a flow chart for determining whether the pressing of the upper and lower shells meets the preset standards under an accelerated traversal heating method according to an embodiment of the present invention.

[0034] An embodiment of the present invention provides a method for pressing together upper and lower shells of a battery pack based on secondary activation, comprising:

[0035] Step S1, collecting an image of the adhesive coating surface of the battery pack lower shell to obtain the area ratio of the effective activation area;

[0036] Step S2, determining an initial heating mode based on a comparison between the effective activation area ratio and a preset ratio, wherein the initial heating mode includes a uniform traversal heating mode and an accelerated traversal heating mode;

[0037] Step S3: Leave a preset distance of 15 mm between the glue-coated surface of the lower shell and the surface to be bonded of the upper shell, and use an infrared heating device to perform secondary activation of the glue in accordance with the initial heating method;

[0038] Step S4, using a press to sequentially complete the pressing and pressure-maintaining of the upper and lower shells of the battery pack;

[0039] Step S5, in response to the uniform speed traversal heating method, sampling and obtaining an average interface bonding strength, and determining whether the pressing of the upper and lower shells meets a preset standard based on the average interface bonding strength; if the preset standard is not met, increasing the heat input power of the infrared heating device, or determining, based on a pressing characteristic area, that the reasons for the pressing not meeting the preset standard include a pressing speed not meeting the standard and a traversal speed not meeting the standard; the pressing characteristic area is the integral area of the pressing time-upper shell displacement curve;

[0040] Step S6, in response to the random inspection of the accelerated traversal heating method, obtaining an average value of the interface bonding strength and determining whether the pressing of the upper and lower shells meets a preset standard based on the average value of the interface bonding strength. If the preset standard is not met, the reasons for not meeting the preset standard are determined to include insufficient hot melt or substandard traversal acceleration based on a bonding consistency characteristic value; the bonding consistency characteristic value is the difference in interface bonding strength between the initial heating area and the final heating area of the adhesive coating surface;

[0041] Step S7, removing the adhesive wires of the battery pack where the upper and lower shells are pressed together to meet the preset standards.

[0042] It should be pointed out that the data in this embodiment are all the results obtained through preliminary experimental verification by the method described in the present invention before this preparation. The preset values can be adjusted according to the specific usage, as long as the method described in the present invention can clearly define the different specific situations in the single determination process through the obtained numerical values.

[0043] Specifically, the adhesive that needs secondary activation in this embodiment is EPP material. EPP material has very high requirements for the pressing temperature. Too high a temperature will cause the EPP rebound rate to decrease, while too low a temperature will affect the interface bonding strength. Figure 2 , the inside of the black frame is the glue-coated surface.

[0044] Specifically, the equipment used in the method of the present invention is a secondary activation pressing device, which includes an industrial computer, an infrared heating device, a slide rail, a press, an upper mold, and a lower mold. The industrial computer is respectively connected to an industrial camera for collecting images of the glue-coated surface of the lower shell of the battery pack. The industrial computer is also provided with a parameter entry unit, which should be used to enter the product parameters obtained by random inspection, including the average value of the interface bonding strength, the pressing characteristic area and the bonding consistency characteristic value. When loading, the lower shell subassembly is installed on the lower mold by a robot gripper. The upper mold must ensure that the upper shell and the lower shell maintain a certain distance and have enough space to allow the infrared heating device to enter. At this time, the infrared heating device slides in along the slide rail to perform secondary activation on the hot melt adhesive of the lower shell. After activation, the infrared heating device slides out, the press is pressed down, and pressing begins. The pressing pressure is greater than 80T and the pressing time is 60s. After completion, the pressure holding begins. The pressure holding pressure is greater than 10T and the pressure holding time is 9min.

[0045] Specifically, in response to the effective activation area area ratio being less than the preset ratio of 15.50%, the initial heating method is determined to be the accelerated traversal heating method, and in response to the effective activation area area ratio being greater than or equal to the preset ratio, the initial heating method is determined to be the uniform traversal heating method; the effective activation area area ratio is the area ratio of the glued surface in the preset area area collected on the glued surface of the battery pack lower shell; referring to the structural schematic diagram of the glued surface of the battery pack lower shell, it can be understood that the glued surface has completed the gluing, leveling and preliminary curing before the secondary activation. Due to the discontinuous uniform linear state of the glue, the shape and area of the glued surface of each battery pack lower shell are different in the top view, and the corresponding thickness is also different. In this way, for thicker glue and larger width, the heat storage capacity of the glue itself is large. Therefore, the uniform traversal heating method can ensure the consistency of the entire heating surface before bonding. For thinner glue and smaller width, the heat storage capacity of the glue itself is small, and it is heated by the accelerated traversal heating method, thereby increasing the heating speed and ensuring the consistency of the front and rear end heating surfaces before bonding.

[0046] Specifically, the uniform traversal heating method is that the infrared heating device covers the glue-coated surface of the lower shell of the battery pack and heats it from the head end to the tail end at a uniform speed along the long-range direction of the lower shell; the accelerated traversal heating method is that the infrared heating device covers the glue-coated surface of the lower shell of the battery pack and heats it from the head end to the tail end at a preset acceleration along the long-range direction of the lower shell; in this embodiment, for the uniform traversal heating method, the heat input power of the external heating device and the initial speed of the infrared heating device are not specifically limited, for example, the heat input power is 15kW, and the initial speed is 4.5m / min; for the accelerated traversal heating method, the heat input power of the external heating device and the initial speed of the infrared heating device are also not specifically limited, for example, the heat input power is 18kW, the initial speed is 4.5m / min, and the preset acceleration is 1.35m / min 2, which can be set according to the equipment and actual production conditions on site.

[0047] Specifically, in step S5, when the average value of the interface bonding strength is less than the second preset strength threshold, it is determined that the pressing of the upper and lower shells does not meet the preset standard; when the average value of the interface bonding strength is greater than or equal to the second preset strength threshold, it is determined that the pressing of the upper and lower shells meets the preset standard; when the average value of the interface bonding strength is greater than or equal to the first preset strength threshold and less than the second preset strength threshold, the reason why the pressing does not meet the preset standard is determined based on the pressing characteristic area, and when the average value of the interface bonding strength is less than the first preset strength threshold, the heat input power of the infrared heating device for the next batch of pressing is increased; the increase in the heat input power of the infrared heating device is positively correlated with the difference between the first preset strength threshold and the average value of the interface bonding strength; wherein, the average value of the interface bonding strength is the average value of the interface bonding strengths of several bonding points, and the interface bonding strength of the sample is measured by a shear test; wherein, the second preset strength threshold is set to 2.50MPa, and the first preset strength threshold is set to 2.35MPa. It can be understood that when the average value of the interface bonding strength is greater than or equal to the second preset strength threshold of 2.50MPa, it is determined that the pressing of the upper and lower shells meets the preset standard, the sampling inspection is directly determined to be qualified and the production parameters in the sampling inspection cycle are determined to continue to be used in the next sampling inspection cycle. When the average value of the interface bonding strength is less than the second preset strength threshold of 2.50MPa, it is determined that the pressing of the upper and lower shells does not meet the preset standard. And, when the average value of the interface bonding strength is greater than or equal to the first preset strength threshold of 2.35MPa and less than the second preset strength threshold of 2.50MPa, it is preliminarily determined that the pressing of the upper and lower shells does not meet the preset standard. It is necessary to verify the reasons for not meeting the preset standards based on some features in the pressing process. In this embodiment, the pressing feature area is selected. The pressing feature area represents the reaction force exerted on the upper mold during the pressing process, thereby indirectly reflecting the uniformity and soft and hard state of the colloid after the secondary activation; if the average value of the interface bonding strength is less than the first preset strength threshold 2 .35MPa, it is directly determined that the reason for not meeting the preset standard is insufficient activation of the colloid, thereby directly increasing the heat input power of the infrared heating device for the next batch of pressing; the increase in the heat input power of the infrared heating device is positively correlated with the difference between the first preset strength threshold and the mean value of the interface bonding strength. It can be understood that the positive correlation can be a linear positive correlation or a nonlinear positive correlation, and is not specifically limited. The slope of the linear positive correlation is also not specifically limited. For example, under linear positive correlation adjustment, the increase in the heat input power is set to △I, and the difference between the first preset strength threshold and the mean value of the interface bonding strength is set to △Φ, then △I=α×△Φ, α is the linear adjustment coefficient of the heat input power, and α is set to 1.02, which satisfies the condition that the greater the difference between the first preset strength threshold and the mean value of the interface bonding strength, the greater the increase in the heat input power of the infrared heating device for the next batch of pressing.

[0048] Specifically, when the pressing characteristic area is smaller than the preset characteristic area, it is determined that the reason for not meeting the preset standard is that the pressing speed does not meet the standard, and when the pressing characteristic area is greater than or equal to the preset characteristic area, it is determined that the reason for not meeting the preset standard is that the traversal speed does not meet the standard; here, the pressing characteristic area characterizes the reaction force exerted on the upper mold during the pressing process, thereby indirectly reflecting the uniformity and soft and hard state of the colloid after the secondary activation. When the pressing characteristic area is smaller than the preset characteristic area, the colloid after the secondary activation is relatively soft, and if the corresponding pressing speed is too fast, the colloid cannot fully dissipate heat and effectively deform the adhesion. When the pressing characteristic area is smaller than the preset characteristic area, the colloid after the secondary activation is relatively soft. When the characteristic area is greater than or equal to the preset characteristic area, the hardness of the colloid core after the secondary activation is higher, so appropriately reducing the traversal speed can overcome this problem. Here, the pressing characteristic area is the integral area of the pressing time-upper shell displacement curve. The pressing time-upper shell displacement curve uses the pressing time as the horizontal coordinate and the upper shell displacement as the vertical coordinate. The unit of the pressing time is s, and the upper shell displacement is mm. The upper shell displacement of the pressing stroke is set to 3mm, and the pressing time is set to the time of the stroke to 5s. The preset characteristic area is, for example, 7.5mm·s. The preset characteristic area can also be specifically set according to the equipment and actual production conditions on site.

[0049] Specifically, in response to the pressing speed not meeting the standard, the pressing speed of the upper and lower shells of the next batch of battery packs is reduced, and the reduction amplitude of the pressing speed of the upper and lower shells of the next batch of battery packs is positively correlated to the difference between the preset characteristic area and the pressing characteristic area; here, it is only necessary to satisfy that the greater the difference between the preset characteristic area and the pressing characteristic area, the greater the reduction amplitude of the pressing speed of the upper and lower shells of the next batch of battery packs. The positive correlation can be referred to increasing the heat input power of the infrared heating device for pressing the next batch, which will not be repeated here; in response to the traversal speed not meeting the standard, the traversal speed of the upper and lower shells of the next batch of battery packs is reduced, and the reduction amplitude of the traversal speed of the upper and lower shells of the next batch of battery packs is positively correlated to the difference between the pressing characteristic area and the preset characteristic area. Here, it is only necessary to satisfy that the greater the difference between the pressing characteristic area and the preset characteristic area, the greater the reduction amplitude of the traversal speed of the upper and lower shells of the next batch of battery packs, which will not be repeated here.

[0050] Specifically, in step S6, when the average value of the interface bonding strength is less than the second preset strength threshold, it is determined that the pressing of the upper and lower shells does not meet the preset standard; when the average value of the interface bonding strength is greater than or equal to the second preset strength threshold, it is determined that the pressing of the upper and lower shells meets the preset standard, wherein the second preset strength threshold is set to 2.50 MPa.

[0051] Specifically, in step S6, when the bonding consistency characteristic value is less than the preset consistency characteristic threshold, it is determined that the reason for not meeting the preset standard is insufficient hot melt, and when the bonding consistency characteristic value is greater than or equal to the preset consistency characteristic threshold, it is determined that the reason for not meeting the preset standard is that the traversal acceleration does not meet the standard; the bonding consistency characteristic value is the difference in interface bonding strength between the initial heating area and the termination heating area of the glue coating surface. It can be understood that the smaller the bonding consistency characteristic value, the higher the consistency of the secondary activation of the front and rear end heating surfaces. On the contrary, the larger the bonding consistency characteristic value, the poorer the consistency of the secondary activation of the front and rear end heating surfaces. The preset consistency characteristic threshold is set to 0.08MPa.

[0052] Specifically, in response to insufficient hot melting, the heat input power of the next batch of pressing is increased, and the increase in the heat input power is positively correlated with the difference between the preset consistency characteristic threshold and the bonding consistency characteristic value; here, the adjustment of the increase in the heat input power refers to the adjustment of the increase in the heat input power of the infrared heating device for the next batch of pressing, which will not be repeated here; in response to the traversal acceleration not meeting the standard, the preset acceleration of the next batch of pressing is reduced, and the reduction in the preset acceleration is positively correlated with the difference between the bonding consistency characteristic value and the preset consistency characteristic threshold; here, the adjustment of the reduction in the preset acceleration also refers to the adjustment of the increase in the heat input power of the infrared heating device for the next batch of pressing, which will not be repeated here.

[0053] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0054] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for pressing the upper and lower shells of a battery pack based on secondary activation, characterized in that: include: Step S1, collecting an image of the adhesive coating surface of the battery pack lower shell to obtain the area ratio of the effective activation area; Step S2, determining an initial heating mode based on a comparison between the effective activation area ratio and a preset ratio, wherein the initial heating mode includes a uniform traversal heating mode and an accelerated traversal heating mode; Step S3: leaving a preset distance between the glue-coated surface of the lower shell and the surface to be bonded of the upper shell, and performing secondary activation of the glue using an infrared heating device according to the initial heating method; Step S4, using a press to sequentially complete the pressing and pressure-maintaining of the upper and lower shells of the battery pack; Step S5, in response to the random inspection of the uniform speed traversal heating method to obtain an average value of the interface bonding strength, and determining based on the average value of the interface bonding strength that the pressing of the upper and lower shells does not meet the preset standard, increasing the heat input power of the infrared heating device, or determining based on the pressing characteristic area that the reasons for the pressing not meeting the preset standard include a pressing speed not meeting the standard and a traversal speed not meeting the standard; the pressing characteristic area is the integral area of the pressing time-upper shell displacement curve; Step S6, in response to the random inspection of the accelerated traversal heating method to obtain an average value of the interface bonding strength, and determining based on the average value of the interface bonding strength that the pressing of the upper and lower shells does not meet the preset standard, determining based on the bonding consistency characteristic value that the reasons for not meeting the preset standard include insufficient hot melt or substandard traversal acceleration; the bonding consistency characteristic value is the difference in interface bonding strength between the initial heating area and the final heating area of the adhesive coating surface; Step S7, removing the adhesive wires of the battery pack where the upper and lower shells are pressed together and meet the preset standards; The uniform traversal heating method is that the infrared heating device covers the glue-coated surface of the lower shell of the battery pack and heats from the head end to the tail end at a uniform speed along the long-range direction of the lower shell; the accelerated traversal heating method is that the infrared heating device covers the glue-coated surface of the lower shell of the battery pack and heats from the head end to the tail end along the long-range direction of the lower shell at a preset acceleration.

2. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 1, characterized in that: In response to the effective activation area area ratio being less than the preset ratio, the initial heating method is determined to be the accelerated traversal heating method, and in response to the effective activation area area ratio being greater than or equal to the preset ratio, the initial heating method is determined to be the uniform traversal heating method.

3. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 1, characterized in that: In step S5, when the average value of the interface bonding strength is less than the second preset strength threshold, it is determined that the pressing of the upper and lower shells does not meet the preset standard; when the average value of the interface bonding strength is greater than or equal to the first preset strength threshold and less than the second preset strength threshold, the reason why the pressing does not meet the preset standard is determined based on the pressing characteristic area; and when the average value of the interface bonding strength is less than the first preset strength threshold, the heat input power of the infrared heating device for the next batch of pressing is increased.

4. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 3, characterized in that: The increase in the heat input power of the infrared heating device is positively correlated to the difference between the first preset intensity threshold and the average value of the interface bonding strength.

5. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 3, characterized in that: When the pressing feature area is smaller than the preset feature area, it is determined that the reason for not meeting the preset standard is that the pressing speed does not meet the standard; and when the pressing feature area is greater than or equal to the preset feature area, it is determined that the reason for not meeting the preset standard is that the traversing speed does not meet the standard.

6. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 5, characterized in that: In response to the pressing speed not meeting the standard, the pressing speed of the upper and lower shells of the next batch of battery packs is reduced, and the reduction in the pressing speed of the upper and lower shells of the next batch of battery packs is positively correlated with the difference between the preset characteristic area and the pressing characteristic area; in response to the traversing speed not meeting the standard, the traversing speed of the upper and lower shells of the next batch of battery packs is reduced, and the reduction in the traversing speed of the upper and lower shells of the next batch of battery packs is positively correlated with the difference between the pressing characteristic area and the preset characteristic area.

7. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 1, characterized in that: In step S6, when the average value of the interface bonding strength is less than a second preset strength threshold, it is determined that the pressing of the upper and lower shells does not meet the preset standard.

8. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 1, characterized in that: In step S6, when the bonding consistency characteristic value is less than the preset consistency characteristic threshold, it is determined that the reason for not meeting the preset standard is insufficient hot melt, and when the bonding consistency characteristic value is greater than or equal to the preset consistency characteristic threshold, it is determined that the reason for not meeting the preset standard is that the traversal acceleration does not meet the standard.

9. The method for pressing the upper and lower shells of a battery pack based on secondary activation according to claim 8, characterized in that: In response to insufficient hot melt, the heat input power of the next batch of pressing is increased, and the increase in the heat input power is positively correlated with the difference between the preset consistency characteristic threshold and the bonding consistency characteristic value; In response to the traversal acceleration not meeting the standard, the preset acceleration of the next batch of pressing is reduced, and the reduction amplitude of the preset acceleration is positively correlated with the difference between the bonding consistency characteristic value and the preset consistency characteristic threshold.

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