Pouch-type lithium-ion polymer battery cell module and method of manufacturing the same

Abstract

The present disclosure provides a soft package lithium ion polymer battery cell module and a preparation method thereof. The soft package lithium ion polymer battery cell module comprises a shell, two soft package battery cells and a protection plate. The two soft package battery cells are arranged side by side in the shell, and the protection plate is arranged at the same end of the two soft package battery cells. Each soft package battery cell comprises an aluminum plastic shell, a bare battery cell, a tab sheet, a tab sealing layer and a curing member. The tab sheet comprises a packaging section, a first bending section and a second bending section connected in sequence. The packaging section is led out from the aluminum plastic packaging part. The first bending section is bent towards the direction of the bare battery cell and is clamped between the protection plate and the aluminum plastic packaging part. The second bending section is perpendicular to the first bending section. Two curing members are arranged on opposite sides of the packaging section. The tab sheet bending utilizes the gap between the protection plate and the aluminum plastic packaging part, and the protection plate is close to the end face of the aluminum plastic packaging part, thereby improving the volume energy density. The curing member and the tab sealing layer form a seal to block the infiltration of external moisture into the battery cell.

Description

Technical Field

[0001] This disclosure relates to the technical field of lithium-ion batteries, and in particular to a soft-pack lithium-ion polymer cell module and its preparation method. Background Technology

[0002] A pouch cell module consists of a housing and cells. To achieve higher voltage or capacity within a limited housing space and to optimize the module's structural layout and energy density, pouch cells are connected in parallel to increase the module's energy and meet range requirements. During the production of a pouch cell module, tabs with attached adhesive are encapsulated within an aluminum-plastic film housing and heat-sealed to form the pouch cell. Subsequently, the cell tabs are soldered to corresponding pads on the protection board, and the tabs are bent to complete the module assembly.

[0003] However, when assembling the pouch cells with the control board, the solder pads are located on the side of the control board away from the cell slots. When the tabs are connected to the solder pads and bent, both the solder pads and the bent tabs occupy the limited internal height of the pouch battery module, which leads to an increase in the overall size of the module and a decrease in the overall energy density of the module. Furthermore, during the bending process of the tabs, the stress generated by the bending moment is mainly concentrated at the root of the tabs. Repeated or excessive bending can easily cause micro-cracks or peeling at the interface, allowing external moisture to easily seep into the cell along the joint, thus affecting the long-term cycle life and safety of the cell. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a soft-pack lithium-ion polymer battery module that reduces space occupation, increases energy density, and blocks the intrusion of external moisture, as well as its preparation method.

[0005] The purpose of this disclosure is achieved through the following technical solution: A soft-pack lithium-ion polymer battery module includes a housing, two soft-pack batteries and a protection board. The two soft-pack batteries are arranged side by side in the housing. The protection board is disposed at the same end of the two soft-pack batteries, and a solder pad is provided on the side of the protection board adjacent to the soft-pack battery. Each of the aforementioned soft-pack battery cells includes an aluminum-plastic shell, a bare battery cell, tabs, a tab sealing layer, and a curing component. The aluminum-plastic shell is heat-pressed and encapsulated over the bare battery cell, forming an aluminum-plastic encapsulation portion. The tab includes a sequentially connected encapsulation segment, a first bending segment, and a second bending segment. The encapsulation segment is soldered to the bare battery cell and extends out from the aluminum-plastic encapsulation portion. The first bending segment bends towards the bare battery cell, is parallel to the thickness direction of the protective plate, and is sandwiched between the protective plate and the aluminum-plastic encapsulation portion. The second bending segment extends in a direction perpendicular to the first bending segment and is soldered to the pad. Two curing components are disposed on opposite sides of the encapsulation segment. The tab sealing layer is attached to the outer surface of the encapsulation segment and the curing component. The end face of the tab sealing layer and the curing component facing away from the bare battery cell is flush with the end face of the aluminum-plastic encapsulation portion.

[0006] In one embodiment, the included angle between the first bending segment and the encapsulation segment is 165°-180°.

[0007] In one embodiment, each of the aluminum-plastic shells has a sealing edge on both sides, and the two sealing edges are respectively attached to both sides of the protective plate along its length.

[0008] In one embodiment, the sum of the widths of the two edge banding portions is less than the width of the protective plate.

[0009] In one embodiment, the extension direction of the cured member is parallel to the lead-out direction of the tab, and the projection of the cured member in the thickness direction of the tab covers the encapsulation segment.

[0010] In one embodiment, the tabs of the two pouch cells are arranged symmetrically along the length of the protection plate.

[0011] In one embodiment, the outer surface of the first bent section is covered with an insulating protective layer, which is a polyimide tape or a heat-shrinkable insulating sleeve.

[0012] A method for preparing a pouch-type lithium-ion polymer battery cell module, the method being used to prepare the pouch-type lithium-ion polymer battery cell module according to any of the above embodiments, comprising the following steps: The tab adhesive is coated onto the tab piece, and one end of the tab piece is soldered to the bare battery cell. Then, it is placed into an aluminum-plastic shell for thermo-press encapsulation. The aluminum-plastic shell forms an aluminum-plastic encapsulation part at the thermo-pressing position. The tab piece is led out from the aluminum-plastic encapsulation part to form the lead end of the tab piece. The encapsulation part forms an opening at the end away from the bare battery cell at the thermo-pressing position. One end of the tab adhesive is exposed in the aluminum-plastic encapsulation part and covers the lead end of the tab piece to obtain the initial battery cell. The initial battery cell is laser-cleaned to remove the opening of the aluminum-plastic shell and the portion of the tab adhesive near the opening of the lead-out end of the tab, so that the outer periphery of the aluminum-plastic shell and the outer periphery of the tab adhesive at the lead-out end of the tab are flush, thereby obtaining a soft-pack battery cell. The leads of the two tabs of the pouch cells are soldered to the pads on both sides of the protection board, respectively. The lead-out ends of the two pouch cells are bent for the first time near the protective plate so that the lead-out ends of the two pouch cells are arranged parallel to the thickness direction of the protective plate and located on both sides of the protective plate. The leads of the two pouch cells are bent a second time so that the leads of the two pouch cells are bent near the aluminum-plastic shell so that the protection plate is embedded between the hot-pressed positions of the two cells to obtain a dual-cell structure. The dual-cell structure is installed inside the housing to obtain a soft-pack lithium-ion polymer cell module.

[0013] In one embodiment, the initial tabs are laser-cleaned to remove the openings in the aluminum-plastic shell of the initial battery cell and the tab adhesive at the lead-out ends of the initial battery cell, in order to obtain a soft-pack battery cell. This includes the following steps: Laser rough cleaning is performed on the opening of the aluminum-plastic shell of the initial battery cell and the tab adhesive at the lead-out end of the tab. Laser finishing is performed on the opening of the aluminum-plastic shell of the initial battery cell and the tab adhesive at the lead end of the tab to obtain a soft-pack battery cell.

[0014] In one embodiment, the feature is that coaxial air blowing is performed simultaneously during laser rough cleaning and laser fine cleaning, the air blowing pressure of the coaxial air blowing is 0.1MPa-0.3MPa, and the angle between the air blowing direction of the coaxial air blowing and the laser beam direction of the laser cleaning is 30°-60°.

[0015] Compared with the prior art, this disclosure has at least the following advantages: In the aforementioned soft-pack lithium-ion polymer battery cell module, the first bent section of the tab is folded back towards the bare cell and sandwiched between the protection board and the aluminum-plastic encapsulation part. This fully utilizes the gap between the protection board and the aluminum-plastic encapsulation part of the bare cell. At the same time, the end face of the tab sealing layer and the curing component facing away from the bare cell is flush with the end face of the aluminum-plastic encapsulation part, allowing the protection board to be as close as possible to the end face of the aluminum-plastic encapsulation part, reducing the space occupied by the soft-pack cell in the height direction, and improving the volumetric energy density of the soft-pack lithium-ion polymer battery cell module. The curing component fills the transition area between the tab and the tab sealing layer, eliminating the interface gap in the transition area. The curing component shares the bending stress, preventing micro-cracks or peeling from forming in the aluminum-plastic encapsulation part. Under the synergistic effect of the rigid support of the curing component and the flexible sealing of the tab sealing layer, the path of external moisture seeping into the cell along the tab outlet interface is effectively blocked, thereby improving the long-term cycle life and safety of the soft-pack lithium-ion polymer battery cell module. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a soft-pack lithium-ion polymer battery module according to an embodiment; Figure 2 for Figure 1 A cross-sectional view of a soft-pack lithium-ion polymer battery module shown. Figure 3 for Figure 1 Another structural schematic diagram of the soft-pack lithium-ion polymer battery module is shown. Figure 4 This is a flowchart illustrating the steps of a method for preparing a soft-pack lithium-ion polymer battery module according to an embodiment.

[0018] Reference numerals: 10-Soft-pack lithium-ion polymer cell module; 100-Shell; 200-Soft-pack cell; 210-Aluminum-plastic shell; 211-Aluminum-plastic encapsulation part; 212-Edge sealing part; 220-Bare cell; 230-Electrical tab; 231-Encapsulation section; 232-First bending section; 2321-; 233-Second bending section; 240-Electrical tab sealing layer; 250-Curved component; 300-Protective board. Detailed Implementation

[0019] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0020] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments: Please see Figures 1 to 3 As shown, this is a soft-pack lithium-ion polymer battery cell module 10 according to an embodiment of the present invention, including a housing 100, two soft-pack battery cells 200 and a protection plate 300. The two soft-pack battery cells 200 are arranged side by side in the housing 100. The protection plate 300 is disposed at the same end of the two soft-pack battery cells 200, and a solder pad 310 is provided on the side of the protection plate 300 adjacent to the soft-pack battery cell 200. Further, each of the aforementioned soft-pack battery cells 200 includes an aluminum-plastic shell 210, a bare battery cell 220, a tab 230, a tab sealing layer 240, and a curing element 250. The aluminum-plastic shell 210 is heat-pressed and encapsulated over the bare battery cell 220. The aluminum-plastic shell 210 forms an aluminum-plastic encapsulation portion 211. The tab 230 includes an encapsulation section 231, a first bending section 232, and a second bending section 233 connected in sequence. The encapsulation section 231 is soldered to the bare battery cell 220 and leads out from the aluminum-plastic encapsulation portion 211. The first bending section 232 bends towards the bare battery cell 220. 232 is parallel to the thickness direction of the protection plate 300 and sandwiched between the protection plate 300 and the aluminum-plastic encapsulation part 211. The second bending segment 233 extends in a direction perpendicular to the first bending segment 232 and is welded to the pad 310. The two curing components 250 are disposed on opposite sides of the encapsulation segment 231. The tab sealing layer 240 is attached to the outer surface of the encapsulation segment 231 and the curing component 250. The end faces of the tab sealing layer 240 and the curing component 250 away from the bare cell 220 are flush with the end face of the aluminum-plastic encapsulation part 211.

[0023] In this embodiment, after the encapsulation segment 231 of the tab 230 is led out from the aluminum-plastic encapsulation part 211, the second bending segment 233 of the tab 230 is first soldered to the pad 310. Then, the end of the second bending segment 233 adjacent to the soldering area of ​​the pad 310 away from the pad 310 is bent so that it extends in a direction perpendicular to the subsequent first bending segment 232, so as to avoid the subsequent bending causing traction or deformation to this area. Then, the first bending segment 232 is bent towards the bare cell 220 so that the first bending segment 232 is parallel to the thickness direction of the protection plate 300 and sandwiched between the protection plate 300 and the aluminum-plastic encapsulation part 211. The tab 230 forms a three-segment space from the encapsulation segment 231 to the first bending segment 232 folded back, and from the first bending segment 232 to the second bending segment 233 extending laterally. During the bending process, the end faces of the two curing components 250 and the tab sealing layer 240 are flush with the end face of the aluminum-plastic encapsulation part 211. When the first bending segment 232 bends towards the bare cell 220, the stress generated by the bending is distributed and transferred through the curing component 250, preventing stress concentration at the root of the tab 230 extending from the aluminum-plastic package 211, thus preventing micro-gaps or peeling of the aluminum-plastic package 211 caused by bending stress. Simultaneously, the curing component 250 fills the transition area between the tab 230 and the tab sealing layer 240, eliminating interface gaps and forming a tight, sealed connection.

[0024] In the aforementioned soft-pack lithium-ion polymer battery module 10, the first bent section 232 of the tab 230 is folded back towards the bare battery cell 220 and sandwiched between the protection plate 300 and the aluminum-plastic encapsulation part 211. This fully utilizes the gap between the protection plate 300 and the aluminum-plastic encapsulation part 211 of the bare battery cell 220. At the same time, the end face of the tab sealing layer 240 and the curing component 250 facing away from the bare battery cell 220 is flush with the end face of the aluminum-plastic encapsulation part 211, so that the protection plate 300 is as close as possible to the end face of the aluminum-plastic encapsulation part 211, reducing the space occupied by the soft-pack battery cell 200 in the height direction. This improves the volumetric energy density of the soft-pack lithium-ion polymer cell module 10. The cured component 250 fills the transition area between the tab 230 and the tab sealing layer 240, eliminating the interface gap in the transition area. The cured component 250 shares the bending stress and prevents the aluminum-plastic package 211 from generating micro gaps or peeling. Under the synergistic effect of the rigid support of the cured component 250 and the flexible sealing of the tab sealing layer 240, the path of external moisture to seep into the cell along the tab lead-out interface is effectively blocked, thereby improving the long-term cycle life and safety of the soft-pack lithium-ion polymer cell module 10.

[0025] In one embodiment, the angle between the first bending segment 232 and the encapsulation segment 231 is 165°-180°. In this embodiment, after bending, the first bending segment 232 is close to or completely parallel to the encapsulation segment 231, so that the protective plate 300 is close to the end face of the aluminum-plastic encapsulation part 211, thereby accommodating the bent portion of the tab 230 within the gap between the protective plate 300 and the aluminum-plastic encapsulation part 211. This avoids tilting of the protective plate 300 or local stress concentration caused by excessive angular deviation, and improves the structural stability of the module after assembly.

[0026] like Figure 3 As shown, in one embodiment, each of the aluminum-plastic shells 210 has a sealing edge 212 formed on both sides, and the two sealing edge portions 212 are respectively attached to both sides of the protective plate 300 along its length. In this embodiment, the sealing edge portion 212 and the protective plate 300 form a lateral support abutment, and the sealing edge portion 212 restricts the displacement of the protective plate 300 along its width direction, so that the protective plate 300 is positioned between the two soft-pack battery cells 200, thereby improving the connection stability between the protective plate 300 and the electrode tab 230 solder joint.

[0027] like Figure 3 As shown, in one embodiment, the sum of the widths of the two edge sealing portions 212 is less than the width of the protective plate 300. In this embodiment, the sum of the widths of the two edge sealing portions 212 is less than the width of the protective plate 300, which provides sufficient clearance for the welding and bending operations of the solder pad 310 and the tab 230, and reduces the waste of edge sealing material on both sides of the aluminum-plastic shell 210.

[0028] like Figure 3As shown, in one embodiment, the extending direction of the curing element 250 is parallel to the lead-out direction of the tab 230, and the projection of the curing element 250 in the thickness direction of the tab 230 covers the encapsulation segment 231. In this embodiment, the projection of the curing component 250 on the thickness direction of the tab 230 covers the encapsulation section 231, so that the curing component 250 supports the connection interface between the tab 230 and the aluminum-plastic encapsulation part 211. The curing component 250 bears and disperses stress along the length direction, avoiding stress concentration at the interface between the encapsulation section 231 and the aluminum-plastic encapsulation part 211, preventing cracking or micro-peeling of the aluminum-plastic encapsulation part 211 due to deformation of the tab 230, thereby maintaining the airtight integrity of the aluminum-plastic shell 210 body 100. The curing component 250 is tightly attached to both sides of the interface of the encapsulation section 231, so that the tab sealing layer 240 forms a covering seal on the outer surface of the tab 230, preventing moisture from penetrating into the interior of the soft-pack battery cell 200, and improving the safety performance of the soft-pack lithium-ion polymer battery cell module 10.

[0029] like Figure 2 As shown, in one embodiment, the tabs 230 of the two pouch cells 200 are symmetrically arranged along the length of the protection plate 300. In this embodiment, the connection points of the two tabs 230 to the pads 310 of the protection plate 300 are distributed symmetrically on both sides of the length of the protection plate 300, making the lengths of the output paths from the two pouch cells 200 to the protection plate 300 equal, thereby balancing the charging and discharging currents of the two parallel cells and improving the electrochemical consistency of the parallel pouch cells 200 in the pouch lithium-ion polymer cell module 10. The symmetrical arrangement ensures that the forces exerted by the two tabs 230 on both sides of the protection plate 300 after bending are opposite in direction and equal in magnitude, forming a torque balance, thereby improving the structural stability of the pouch lithium-ion polymer cell module 10 after assembly.

[0030] like Figure 2 As shown, in one embodiment, the outer surface of the first bending segment 232 is covered with an insulating protective layer 2321, which is a polyimide tape or a heat-shrinkable insulating sleeve. In this embodiment, the first bending segment 232 is sandwiched between the protection plate 300 and the aluminum-plastic encapsulation part 211. The space is small and it is close to the electronic components on the protection plate 300. The insulating protective layer protects the first bending segment 232, which significantly improves the electrical safety performance of the soft-pack lithium-ion polymer cell module 10.

[0031] like Figure 4 As shown, this application also provides a method for preparing a soft-pack lithium-ion polymer battery module 10, comprising the following steps: S101, Obtain a tab sheet with tab adhesive covering a metal tab, and inject curing adhesive into the opposite sides of the tab sheet through an adhesive injection device to form a cured part on both sides of the tab sheet; S103, one end of the electrode tab is welded to the bare battery cell, and then it is put into an aluminum-plastic shell for thermo-press encapsulation. The encapsulation position of the aluminum-plastic shell forms an aluminum-plastic encapsulation part; the electrode tab is led out from the aluminum-plastic encapsulation part to obtain the initial battery cell. S105, Laser cleaning is performed on the initial battery cell to remove the aluminum-plastic packaging part and the tab adhesive layer away from the bare battery cell end of the initial battery cell, so that the end of the aluminum-plastic packaging part and the tab adhesive layer are flush, so as to obtain a soft-pack battery cell. S107, the tab leads of the two soft-pack cells are respectively soldered to the pads on both sides of the protection board; S109, the tabs of the two soft-pack cells are bent for the first time near the pads, so that the lead-out ends of the tabs form a first bent section and a second bent section, the second bent section being perpendicular to the first bent section; S111, the tabs of the two soft-pack cells are bent a second time near the aluminum-plastic package, so that the first bending section bends toward the bare cell, and the protection plate is embedded between the hot-pressed positions of the two cells to obtain a dual-cell structure. S113, The dual-cell structure is installed inside the housing to obtain a soft-pack lithium-ion polymer cell module.

[0032] Understandably, the tab adhesive layer is pre-coated onto the surface of the tab 230, and the tab adhesive is fused with the inner hot melt adhesive of the aluminum-plastic shell 210 by hot pressing with a hot press mold to form a sealed and insulating structure. When the aluminum-plastic shell 210 end and the tab adhesive are laser cleaned by scanning with a pulsed laser beam, the laser energy is instantly absorbed by the residual tab adhesive overflow, oxide film or contaminants on the surface, causing them to heat up rapidly, vaporize or peel off. At the same time, the substrate remains intact due to its high reflectivity or low heat-affected threshold, thereby achieving selective cleaning to obtain a clean and residue-free lead-out end of the tab 230.

[0033] Understandably, the first bend causes the second bend to bend along the thickness direction of both sides of the protection board 300 at the adjacent pad 310 of the protection board 300; the second bend causes the first bend section 232 to bend again toward the bare cell 220, so that the first bend section 232 of the tab 230 is attached to the inner wall of the aluminum-plastic encapsulation part 211; through the two bends combined with the opening and tab adhesive residue removed by laser cleaning, the protection board 300 is embedded in the hot-pressed position between the two cells, forming a structure in which the protection board 300 is semi-enclosed by the cells.

[0034] The above-described method for preparing a soft-pack lithium-ion polymer battery module 10 involves laser cleaning to remove the aluminum-plastic shell 210 and the exposed tabs 230, preventing residual tab adhesive and the openings of the aluminum-plastic shell 210 from hindering the bending process of the tabs 230 leads and preventing interference with the protection plate 300 embedded between the two soft-pack cells 200. This results in a compact structure between the protection plate 300 and the soft-pack cells 200, thereby improving the module's energy density. By folding the tabs 230 into the gaps and sidewalls of the soft-pack cells 200 through two bending operations, redundant length of the tabs 230 extending outwards is saved, making the module's projected area in both length and width directions close to the size of a single cell, significantly improving the volumetric energy density. Through the first bending and the second bending... The secondary bending allows the protection plate 300 to be embedded in the aluminum-plastic encapsulation part 211 between the two cells, forming a structure in which the aluminum-plastic shell 210 semi-encloses the protection plate 300. This reduces the exposed area of ​​the protection plate 300 and the impact it receives, thereby improving the safety performance of the battery. The curing component 250 fills the transition area between the tab 230 and the tab sealing layer 240, eliminating the interface gap in the transition area. The curing component 250 shares the bending stress, preventing the aluminum-plastic encapsulation part 211 from developing micro-gaps or peeling. Under the synergistic effect of the rigid support of the curing component 250 and the flexible sealing of the tab sealing layer 240, the path of external moisture seeping into the cell along the tab lead-out interface is effectively blocked, thereby improving the long-term cycle life and safety of the soft-pack lithium-ion polymer cell module 10.

[0035] In one embodiment, the initial battery cell is laser-cleaned to remove the aluminum-plastic encapsulation portion 211 and the tab adhesive layer at the end of the tab 230 facing away from the bare battery cell 220, so that the ends of the aluminum-plastic encapsulation portion 211 and the tab adhesive layer are flush, thereby obtaining a soft-pack battery cell 200. This includes the following steps: Laser rough cleaning is performed on the opening of the aluminum-plastic shell 210 of the initial battery cell and the tab adhesive at the lead end of the tab 230. The opening of the aluminum-plastic shell 210 of the initial battery cell and the tab adhesive at the lead end of the tab 230 are laser-refined to obtain the soft-pack battery cell 200. In this embodiment, a high-energy laser beam is used to quickly remove most of the overflow, oxide layer and contaminants from the opening and the surface of the tab adhesive. A lower-energy laser beam is used to laser-refine the residual micro burrs, thin layer of residual adhesive and edge debris, avoiding the residue problems caused by the first cleaning. During the second laser refinement, a low-energy-density laser is used to reduce heat input and prevent the hot melt adhesive in the inner layer of the aluminum-plastic shell 210 from remelting or deforming, thereby maintaining the sealing effect of the aluminum-plastic shell 210 at the hot pressing position. The lead end surface of the tab 230 after laser refinement is smooth and burr-free, so that the tab path is unobstructed during the first and second bends, and interference with the embedding of the protection plate 300 is avoided, improving the structural compactness and assembly consistency of the module.

[0036] In one embodiment, the pulse width of the laser cleaning is 20ns-80ns, the power of the laser cleaning is 40W-140W, the laser frequency is 100kHz-200kHz during laser rough cleaning, and the line spacing of the rough cleaning is 0.035mm-0.05mm; during laser finishing, the laser frequency is 300kHz-400kHz. In this embodiment, the short pulse width of 20ns-80ns concentrates the laser energy on the surface of the contaminants, resulting in a small thermal impact depth. By adjusting the laser cleaning power to 40W-140W, it is possible to remove aluminum-plastic shells 210 and tab adhesive of different thicknesses or materials. This ensures thorough removal of contaminants while avoiding oxidation, discoloration, or pinhole damage to the aluminum layer of the aluminum-plastic shell 210. The laser cleaning overlap rate is 60%-70%. The coarse cleaning uses a medium frequency of 100kHz-200kHz with a line spacing of 0.035mm-0.05mm. Under the premise of a moderate spot overlap rate, it quickly vaporizes and removes large pieces of overflow and thick layers of contaminants from the opening and the surface of the tab adhesive. The fine cleaning uses a high-frequency laser of 300kHz-400kHz, which results in lower pulse energy and lower peak power, thereby gently peeling off the thin layer of residual adhesive and micro-burrs remaining after the coarse cleaning.

[0037] In one embodiment, coaxial air blowing is performed simultaneously during laser rough cleaning and laser fine cleaning. The air blowing pressure of the coaxial air blowing is 0.1MPa-0.3MPa, and the angle between the air blowing direction of the coaxial air blowing and the laser beam direction of the laser cleaning is 30°-60°. In this embodiment, during the laser cleaning process, when coaxially blowing air, the airflow and the laser beam are sprayed along the same axis. The coaxial blowing air forms a ring or inclined airflow around the laser beam, effectively blowing the vaporized particles away from the cleaning area and preventing them from re-condensing on the cleaned opening or tab surface, thus ensuring that the surface is free from secondary pollution after cleaning. At the lower pressure limit of 0.1 MPa, the airflow is suitable for thin-layer contaminants or heat-sensitive areas. When the pressure is close to the upper limit of 0.3 MPa, the airflow is suitable for quickly removing thick layers of overflow or highly adhesive residues. The blowing direction is at an angle of 30°-60° to the laser beam to avoid 0° blowing interfering with the optical path or causing laser scattering, or when blowing vertically at 90°, the airflow rebounds and forms turbulence, guiding the splashes towards the collection device and preventing contamination of adjacent cell areas.

[0038] Furthermore, in one embodiment, when coaxial air blowing is used to assist laser cleaning, a slightly cooled inert gas is used for blowing. The inert gas is argon or nitrogen, with a temperature of 5°C-15°C, a pressure of 0.2MPa-0.5MPa, and a flow rate of 5L / min-15L / min. In this embodiment, the slightly cooled inert gas carries away the accumulated heat generated by the pulsed laser, reducing the temperature rise of the aluminum-plastic shell 210 and the tab adhesive substrate, preventing thermal deformation at the hot-pressing position of the aluminum-plastic shell 210, thereby maintaining the sealing of the hot-pressing position of the aluminum-plastic shell 210. The slightly cooled airflow, with a pressure of 0.2MPa-0.5MPa and a flow rate of 5L / min-15L / min, quickly blows away the tab adhesive overflow, smoke, and other byproducts generated by laser vaporization from the cleaning area, preventing them from re-condensing and adhering to the cleaned surface, thereby obtaining a clean lead-out end of the tab 230.

[0039] Furthermore, in one embodiment, before the initial tabs are laser-cleaned to remove the openings of the aluminum-plastic shell 210 of the initial battery cell and the tab adhesive at the lead-out ends of the initial battery cell's tab plates 230, the following steps are also included: A mixture of argon and hydrogen is introduced to perform plasma reduction treatment on the lead-out end of the tab 230, wherein the volume content of the hydrogen is 3%-10%. In this embodiment, after laser cleaning, the copper-plated nickel, aluminum, or nickel tabs have an oxide layer. The lead-out end of the tab 230 is subjected to plasma reduction treatment with hydrogen to remove the oxide on the surface of the lead-out end of the tab 230. Then, the lead-out end of the tab 230 is welded to the pad 310 of the protection plate 300. The absence of an oxide layer on the tab surface improves the welding strength between the lead-out end of the tab 230 and the protection plate 300.

[0040] In one embodiment, during the second bend, the angle between the first bending segment 232 and the encapsulation segment 231 is 165°-180°. In this embodiment, after laser cleaning, the opening and tab adhesive are completely removed, creating conditions for a large-angle bend of 165°-180°, allowing the tab to be as close as possible to the cell surface, thereby improving the volumetric energy density of the soft-pack lithium-ion polymer cell module 10. After the second bend, the lead end of the tab 230, adjacent to the aluminum-plastic shell 210, is folded and close to the cell sidewall or end face, thereby shortening the exposed length of the tab, making the projected area of ​​the module in the length and width directions close to that of a single cell. The relative positions of the bending mold and the tab are deviated, and the tab metal has elastic rebound after bending. The included angle between the first bending section 232 and the encapsulation section 231 is 165°-180°, so that the included angle between the first bending section 232 and the surface of the aluminum-plastic shell 210 after the tab 230 is bent is less than 15°. The height of the tab 230 after bending is controllable, so that the end of the tab 230 fits against the inner side wall of the aluminum-plastic shell 210, avoiding interference between the tab 230 and the control board or occupying the space of the control board.

[0041] In one embodiment, during the second bend, a bending die with an radius (R) greater than 0.5 mm is used, and the bending process is completed through several step-by-step bends, each with an angle of 40°-90°. In this embodiment, a die with an R angle greater than 0.5 mm is used, thereby increasing the radius of curvature of the bending areas of the first bending segment 232 and the encapsulation segment 231, avoiding micro-cracks or metal fatigue generated during bending. The number of bending processes is 2-4 times. Through step-by-step bending combined with die limiting, the bending angle of each step is precisely controlled, ensuring that the embedded position of the protective plate 300 remains consistent. During each bend, a holding time is set to relax the stress of the tab material, thereby eliminating the elastic recovery and internal stress of the tab, improving the long-term reliability of the tab bending.

[0042] Further, the tabs 230 of the two pouch cells 200 are bent near the pads 310 to form a first bent section 232 and a second bent end at the lead-out end of the tabs 230, with the second bent end perpendicular to the first bent section 232. Then, the tabs 230 of the two pouch cells 200 are bent near the aluminum-plastic package 211 to bend the first bent section 232 toward the bare cell 220. Before the protection plate 300 is embedded between the hot-pressed positions of the two cells to obtain a dual-cell structure, the following steps are also included: The bending area at the connection between the first bending segment 232 and the encapsulation segment 231 is preheated at a temperature of 80℃-100℃ for 3s-5s. In this embodiment, preheating raises the temperature of the metal tab 230 and lowers its yield strength, resulting in a more uniform stress distribution in the bending area during the second bending process and preventing the tab 230 from breaking. The short preheating time and low temperature prevent the temperature from being conducted through the tab 230 to the aluminum-plastic shell 210 and affecting the sealing interface at the hot-pressing position of the aluminum-plastic encapsulation part 211.

[0043] Furthermore, in one embodiment, the tabs 230 of the two pouch cells 200 are bent a second time near the aluminum-plastic package 211, so that the first bent section 232 bends toward the bare cell 220, and the protective plate 300 is embedded between the hot-pressed positions of the two cells to obtain a dual-cell structure. Before installing the dual-cell structure in the housing 100 to obtain the pouch lithium-ion polymer cell module 10, the following steps are also included: A UV-curable flexible adhesive is applied at the second bend where the first bending segment 232 connects to the encapsulation segment 231. In this embodiment, the UV-curable flexible adhesive forms an elastic buffer layer after curing. This elastic buffer layer wraps around the tab metal in the bending area and the contact interface between the tab and the aluminum-plastic shell 210, effectively dispersing stress caused by external vibration or impact, thereby preventing fatigue fracture of the tab at the root of the bend. The adhesive layer of the UV-curable flexible adhesive fills the tiny gap between the tab and the aluminum-plastic shell 210, preventing electrolyte leakage or external moisture intrusion, further enhancing sealing reliability. The UV-curable flexible adhesive maintains high elasticity after curing, thus adapting to the slight expansion and contraction during charging and discharging of the battery cell and avoiding rigid cracking. The UV-curable flexible adhesive applied at the connection between the first bending segment 232 and the encapsulation segment 231 improves the insulation performance at the connection between the first bending segment 232 and the encapsulation segment 231, preventing the tab lead from contacting the metal shell 100 and causing a short circuit, thereby improving module safety.

[0044] In one embodiment, the distance between the first bending segment 232 and the second bending end at the first bending position and the protective plate 300 is 0.5mm-2mm. In this embodiment, when the distance between the first bending segment 232 and the second bending end at the first bending position and the protective plate 300 is less than 0.5mm, interference is likely to occur. When the distance between the first bending segment 232 and the second bending end at the first bending position and the protective plate 300 is greater than 3mm, an excessively long suspended section is created between the first bending segment 232 and the second bending end and the protective plate 300, thereby reducing the structural compactness. When the distance between the first bending segment 232 and the second bending end at the first bending position and the protective plate 300 is 0.5mm-3mm, the suspended section of the tab bend is relatively short, improving the structural compactness and enhancing the consistency of the bending angle and position.

[0045] In one embodiment, the distance between the second bending segment 233 and the encapsulation segment 231 at the second bending position and the aluminum-plastic shell 210 is 1mm-3mm. In this embodiment, the distance between the second bending segment 233 and the encapsulation segment 231 at the second bending position and the aluminum-plastic shell 210 is 1mm-2mm, so that the second bending segment 233 near the aluminum-plastic shell 210 is folded and closely adheres to the inner wall of the aluminum-plastic shell 210, thereby shortening the exposed length of the tab 230, reducing the overall size of the module, and allowing the tab 230 to have a reserved bending space during bending to cooperate with a mold with an R angle greater than 0.5mm for step-by-step bending.

[0046] Compared with the prior art, this disclosure has at least the following advantages: In the aforementioned soft-pack lithium-ion polymer battery module 10, the first bent section 232 of the tab 230 is folded back towards the bare battery cell 220 and sandwiched between the protection plate 300 and the aluminum-plastic encapsulation part 211. This fully utilizes the gap between the protection plate 300 and the aluminum-plastic encapsulation part 211 of the bare battery cell 220. At the same time, the end face of the tab sealing layer 240 and the curing component 250 facing away from the bare battery cell 220 is flush with the end face of the aluminum-plastic encapsulation part 211, so that the protection plate 300 is as close as possible to the end face of the aluminum-plastic encapsulation part 211, reducing the space occupied by the soft-pack battery cell 200 in the height direction. This improves the volumetric energy density of the soft-pack lithium-ion polymer cell module 10. The cured component 250 fills the transition area between the tab 230 and the tab sealing layer 240, eliminating the interface gap in the transition area. The cured component 250 shares the bending stress and prevents the aluminum-plastic package 211 from generating micro gaps or peeling. Under the synergistic effect of the rigid support of the cured component 250 and the flexible sealing of the tab sealing layer 240, the path of external moisture to seep into the cell along the tab lead-out interface is effectively blocked, thereby improving the long-term cycle life and safety of the soft-pack lithium-ion polymer cell module 10.

[0047] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A soft-pack lithium-ion polymer battery module, characterized in that, The device includes a housing (100), two soft-pack battery cells (200) and a protection plate (300). The two soft-pack battery cells (200) are arranged side by side in the housing (100). The protection plate (300) is located at the same end of the two soft-pack battery cells (200), and a solder pad (310) is provided on the side of the protection plate (300) adjacent to the soft-pack battery cells (200). Each of the aforementioned soft-pack battery cells (200) includes an aluminum-plastic shell (210), a bare battery cell (220), a tab (230), a tab sealing layer (240), and a curing element (250). The aluminum-plastic shell (210) is heat-pressed and encapsulated over the bare battery cell (220). The aluminum-plastic shell (210) forms an aluminum-plastic encapsulation portion (211). The tab (230) includes an encapsulation section (231), a first bending section (232), and a second bending section (233) connected in sequence. The encapsulation section (231) is welded to the bare battery cell (220) and led out from the aluminum-plastic encapsulation portion (211). The first bending section (232) bends toward the bare battery cell (220). (232) Parallel to the thickness direction of the protective plate (300) and sandwiched between the protective plate (300) and the aluminum-plastic encapsulation part (211), the second bending segment (233) extends in a direction perpendicular to the first bending segment (232), and the second bending segment (233) is welded to the pad (310); the two curing elements (250) are disposed on opposite sides of the encapsulation segment (231), the tab sealing layer (240) is attached to the outer surface of the encapsulation segment (231) and the curing element (250), and the end face of the tab sealing layer (240) and the curing element (250) away from the bare cell (220) is flush with the end face of the aluminum-plastic encapsulation part (211).

2. The soft-pack lithium-ion polymer battery module according to claim 1, characterized in that, The included angle between the first bending segment (232) and the encapsulation segment (231) is 165°-180°.

3. The soft-pack lithium-ion polymer battery module according to claim 1, characterized in that, Each of the aluminum-plastic shells (210) has a sealing edge (212) on both sides, and the two sealing edges (212) are respectively attached to both sides of the protective plate (300) in the length direction.

4. The soft-pack lithium-ion polymer battery module according to claim 3, characterized in that, The sum of the widths of the two edge sealing portions (212) is less than the width of the protective plate (300).

5. The soft-pack lithium-ion polymer cell module according to claim 1, characterized in that, The extension direction of the cured component (250) is parallel to the lead-out direction of the tab (230), and the projection of the cured component (250) in the thickness direction of the tab (230) covers the encapsulation segment (231).

6. The soft-pack lithium-ion polymer cell module according to claim 1, characterized in that, The tabs (230) of the two pouch cells (200) are arranged symmetrically along the length of the protection plate (300).

7. The soft-pack lithium-ion polymer cell module according to claim 1, characterized in that, The outer surface of the first bent section (232) is covered with an insulating protective layer (2321), which is a polyimide tape or a heat-shrinkable insulating sleeve.

8. A method for preparing a soft-pack lithium-ion polymer battery cell module, characterized in that, The method for preparing the soft-pack lithium-ion polymer battery cell module according to any one of claims 1-7 includes the following steps: The tab adhesive is coated onto the tab (230), and one end of the tab (230) is welded to the bare cell (220). The tab is then placed into an aluminum-plastic shell (210) for thermo-press encapsulation. The aluminum-plastic shell (210) forms an aluminum-plastic encapsulation part (211) at the thermo-press position. The tab (230) is led out from the aluminum-plastic encapsulation part (211) to form the lead end of the tab (230). The encapsulation part forms an opening at the end away from the bare cell (220) at the thermo-press position. One end of the tab adhesive is exposed in the aluminum-plastic encapsulation part (211) and covers the lead end of the tab (230) to obtain the initial cell. The initial battery cell is laser-cleaned to remove the opening of the aluminum-plastic shell (210) and the portion of the tab adhesive near the opening of the lead end of the tab (230) so that the outer periphery of the aluminum-plastic shell (210) at the lead end of the tab (230) and the outer periphery of the tab adhesive are flush to obtain a soft-pack battery cell (200). The leads of the tabs (230) of the two pouch cells (200) are soldered to the pads (310) on both sides of the protection board (300); The leads of the tabs (230) of the two pouch cells (200) are bent for the first time near the protective plate (300) so that the leads of the tabs (230) of the two pouch cells (200) are arranged parallel to the thickness direction of the protective plate (300) and located on both sides of the protective plate (300). The leads of the tabs (230) of the two soft-pack cells (200) are bent a second time so that the leads of the two tabs (230) are bent near the aluminum-plastic shell (210) so that the protection plate (300) is embedded between the hot-pressed positions of the two cells to obtain a dual-cell structure. The dual-cell structure is installed inside the housing (100) to obtain a soft-pack lithium-ion polymer cell module.

9. The method for preparing a soft-pack lithium-ion polymer battery module according to claim 8, characterized in that, Laser cleaning is performed on the initial tabs to remove the openings of the aluminum-plastic shell (210) of the initial battery cell and the tab adhesive at the lead-out ends of the initial battery cell's tab plates (230), in order to obtain a soft-pack battery cell (200), including the following steps: Laser rough cleaning is performed on the opening of the aluminum-plastic shell (210) of the initial battery cell and the tab adhesive at the lead end of the tab (230); Laser finishing is performed on the opening of the aluminum-plastic shell (210) of the initial battery cell and the tab adhesive at the lead end of the tab (230) to obtain a soft-pack battery cell (200).

10. The method for preparing a soft-pack lithium-ion polymer battery module according to claim 8, characterized in that, During laser rough cleaning and laser fine finishing, coaxial air blowing is performed simultaneously. The air blowing pressure of the coaxial air blowing is 0.1MPa-0.3MPa, and the angle between the air blowing direction of the coaxial air blowing and the laser beam direction of the laser cleaning is 30°-60°.

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