Pole group head of monomer lead-acid storage battery

Abstract

The invention discloses a plate group head of a monomer lead-acid storage battery, and belongs to the technical field of manufacturing of lead-acid storage batteries. The pole group head is formed by tightly combining a main body piece made of a non-polar high polymer material (such as polypropylene) and an embedded piece made of a polar high polymer material (such as ABS (Acrylonitrile Butadiene Styrene)). The surface of the main body piece is provided with convex textures (the depth is 0.5-1mm) and reinforcing ribs, so that the heat-sealing binding force and the deformation resistance of the main body piece and the sealing bag are enhanced; a multi-layer sealing structure of an annular outer cavity and a cylindrical inner cavity is designed for the embedded part, a lead pole column is fixed through a polar adhesive, and sealing bonding is achieved through a pH response type adhesive and an acid-resistant modified epoxy adhesive. The structure solves the problem of failure of the traditional mechanical seal caused by space limitation of the high-width-to-thickness-ratio battery cell, and the sealing reliability and the service life of the battery in long-term use are remarkably improved and prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of lead-acid battery manufacturing, and particularly relates to a pole group head of a single lead-acid battery. Background Art

[0002] As a key component for encapsulating the battery core, the structural sealing performance of the pole group head of a lead-acid battery directly affects the battery life and safety. In traditional solutions, a single polar material is usually used for integral injection molding, and the seal is achieved through the mechanical extrusion force between the lead pole column and the plastic. However, with the development of battery design towards a high length-width ratio (L / W≥8), the battery core tends to be thinner to improve the formation heat dissipation efficiency, and the bottlenecks of the traditional structure are becoming increasingly prominent: on the one hand, a large assembly space needs to be reserved for mechanical extrusion sealing, which cannot be implemented in thin battery cores with limited pole group head width; on the other hand, it is difficult for a single material to simultaneously meet the requirements of heat-sealing combination with a non-polar polymer material sealing bag and high-strength bonding with a lead pole column (polar material is required), and the conflict in material properties leads to a sharp increase in the risk of interface seal failure.

[0003] In addition, the strong acid environment (pH=0-4) inside the lead-acid battery continuously erodes the sealing interface. Traditional epoxy adhesives are prone to embrittlement and cracking under long-term acid corrosion, causing interface microcracks and gradually expanding, ultimately leading to electrolyte leakage. Moreover, the structural rigidity of the wide and thin pole group head is insufficient, and warping deformation is likely to occur due to stress concentration during the heat-sealing process. Coupled with the limited sealing contact area caused by the smooth surface, the leakage-proof pressure resistance value of the traditional structure is usually lower than 40 kPa, making it difficult to meet the requirements of high-reliability applications. Existing improvement technologies such as composite sealing covers or acid-resistant rubber coatings can locally improve the material tolerance, but they have not solved systematic problems such as the interface coordination of polar / non-polar materials, dynamic acid corrosion self-repair, and anti-deformation of wide and thin structures.

[0004] Therefore, there is an urgent need for a breakthrough pole group head structure that can be compatible with the space constraints of high length-width ratio battery cores, achieve efficient sealing of multi-material interfaces, and have self-repair ability in a strong acid environment, so as to fundamentally improve the long-term sealing reliability of lead-acid batteries. Summary of the Invention

[0005] The purpose of the present invention is to provide a modular and self-sealing and self-repairing soft-pack battery core encapsulation structure, and through the design of a non-polar / polar polymer material composite structure and a special adhesive, an easy-to-maintain and corrosion-resistant pole group head and battery core assembly solution are realized.

[0006] The pole group head of a single lead-acid battery includes a main body part and an embedded part. The material of the main body part is a non-polar polymer material, and the material of the embedded part is a polar polymer material. The main body part and the embedded part are tightly bonded, and the pole group head is installed on the battery cell. A sealing bag is covered outside the battery cell, and the sealing bag is also made of a non-polar polymer material. Based on the requirements of the heat-sealing process, the main body part needs to be made of a non-polar polymer material for heat-sealing combination with the sealing bag. Since the pole group head of the present invention has the structural feature of a relatively high aspect ratio of width to thickness, the traditional mechanical extrusion sealing (realizing sealing by the pressing force between the lead pole column and the non-polar polymer material) cannot be applied due to insufficient space. Therefore, a polar adhesive needs to be selected to fix the lead pole column. For this reason, the embedded part (polar polymer material) is provided to provide a bonding interface with the lead pole column and ensure a tight bonding state between the embedded part and the main body part. The pole group head of a single lead-acid battery, the width of the main body part is L, the thickness is W, and the aspect ratio of width to thickness L / W≥8. The aspect ratio of width to thickness L / W≥8 is used to adapt to and install a battery cell with an aspect ratio of width to thickness L / W>8. In the actual manufacturing process, generally, the aspect ratio of width to thickness L / W≤20. When the aspect ratio of the battery cell is larger, the battery cell will be relatively thinner, so that the water bath can more effectively take away the heat generated by the charge and discharge of the battery cell during the formation process; under appropriate width and thickness conditions, the larger the aspect ratio of the battery cell, the lower the internal temperature of the battery cell during the formation process.

[0007] The pole group head of a single lead-acid battery, the two side surfaces of the main body part are provided with raised textures. The raised textures are parallel lines, and the number of lines is at least one, and the depth range of the lines is 0.5mm - 1mm. The pole group head of the present invention is installed on the battery cell, and the heat-sealing process is used to combine the sealing bag with the pole group head to wrap the battery cell. By limiting the depth range of the raised textures, the contact area between the sealing bag and the pole group head is optimized, ensuring that the raised textures can both enhance the bonding force and will not cause a decrease in material strength due to excessive depth, balancing the sealing performance and structural reliability. When the raised texture is one, two or three, the leak-free pressure resistance values between the sealing bag and the pole group head are 40kPa, 70kPa, and 90kPa respectively. A single texture meets the basic sealing requirements, and multiple textures provide redundant sealing guarantees. Users can flexibly select the design specifications according to the battery working conditions.

[0008] The pole group head of a single lead-acid battery, the surface of the main body part is provided with a rib structure. The anti-deformation ability of the main body part is improved through the rib structure, and the integrity of the sealing interface is guaranteed. The ribs can disperse the stress generated during the encapsulation process, prevent the main body part from warping, and avoid sealing failure caused by material fatigue after long-term use.

[0009] The pole group head of a single lead-acid battery has an annular outer cavity inside the insert. There are positioning ribs in the annular outer cavity, and a through cylindrical inner cavity is provided in the middle of the insert. The insert constructs a multi-level sealed cavity structure including the annular outer cavity and the cylindrical inner cavity, realizing the separation of the functions of conduction and sealing. The annular outer cavity serves as a glue storage space to ensure the uniform distribution of glue along the surface of the insert, and the positioning ribs play a guiding and limiting role.

[0010] The pole group head of a single lead-acid battery has a lead pole post on the battery cell, and the lead pole post cooperates with the cylindrical inner cavity. Through the cooperation between the lead pole post and the cylindrical inner cavity, a conductive path is established and the welding port of the lead pole post is reserved. The tight cooperation between the lead pole post and the cylindrical inner cavity prevents acid solution from penetrating into the inside of the pole group. Before the pole group head is installed on the battery cell, a certain amount of sealing glue is first added to the cylindrical inner cavity and the annular outer cavity. The lead pole post of the battery cell cooperates with the cylindrical inner cavity filled with glue, squeezing out the internal sealing glue into the annular outer cavity. After the glue solidifies, the lead pole post is fixed.

[0011] The pole group head of a single lead-acid battery has a main body part made of polypropylene and an insert made of a terpolymer of acrylonitrile, butadiene, and styrene (ABS). The part of the pole group head in contact with the sealing bag is made of polypropylene (PP). Under certain temperature conditions, it has a high bonding force with the sealing bag during heat sealing, making it difficult for the two to peel off, ensuring the sealing of the main body inside the battery cell. The PP material can withstand a pH range of about 2 - 12 at 80°C, and the range is larger than that of the ABS material used for the covers of ordinary lead-acid battery cases (the pH tolerance range is about 4 - 10), with better acid and corrosion resistance. A single-layer or multi-layer texture structure is designed on the contact surface between the pole group head and the sealing bag to increase the heat-sealing contact surface area and enhance the bonding force between the two. The material of the contact surface between the insert and the lead pole post is ABS plastic. ABS contains acrylonitrile polar groups. Compared with non-polar plastics such as PE and PP, the surface energy of ABS is relatively high, about 36 - 42 mN / m. It is easier to form physical adsorption or chemical bonding with the lead element in the lead-acid battery. Other plastics such as PP are completely non-polar materials with low surface energy and weak bonding force with metals in their natural state. Therefore, the part of the insert in contact with the lead pole post uses ABS polar material. Further, the strength of the ABS material is higher than that of PP, which can provide better protection for the lead pole post. Compared with the traditional integrated pole group head structure, assembling the main body part and the insert with two different materials, ABS and PP, can give full play to the advantages of the two materials.

[0012] A pole group head of a single lead-acid battery, a pH-responsive adhesive is added to the bonding interface between the main body and the embedded part. The pH-responsive adhesive contains acid-responsive microcapsules. The components of the pH-responsive adhesive include borate bond prepolymer, and epoxy acrylate hybrid resin, TPO-L (ethyl 2,4,6-trimethylbenzoyl phenylphosphinate), and dicumyl peroxide can also be added. The shell material of the acid-responsive microcapsule is polymethyl methacrylate-co-maleic anhydride, and the core material is pentaerythritol triacrylate. The dynamic borate bonds in the dynamic borate bond prepolymer will trigger recombination during the acid etching of the electrolyte (pH ≤ 3). The microcapsule shell selectively ruptures when the H + concentration > 0.15 mmol / L, releasing repair monomers to quickly fill the microcracks at the interface. At the same time, the dynamic reconstruction of the borate network enhances the molecular entanglement at the interface between non-polar polymers and polar polymers, realizing the dual effects of self-repair and mechanical enhancement in an acid-etching environment. The epoxy acrylate hybrid resin provides a rigid skeleton for the adhesive and forms a dense protective layer at the same time, slowing down the erosion rate of the electrolyte; TPO-L is a UV light-triggered curing agent, and dicumyl peroxide is a heat-triggered curing agent. The two cooperate to completely cure the glue in the gradient curing process, ultimately ensuring that the bonding interface between the embedded part and the main body is tightly sealed, and ensuring the internal tightness of the battery cell after the pole group head and the sealing bag are encapsulated.

[0013] The pole group head of a single lead-acid battery has the contact surface between the lead pole column and the insert sealed with epoxy glue. The epoxy glue contains acid-resistant modification components of long-chain alkyl organosilicon compounds and tetraethoxysilane. The insert material is ABS. The epoxy glue and ABS usually exhibit a relatively high bonding strength (about 5 - 20 MPa), due to the hydrogen bonding or dipole interaction formed between the polar surface of ABS (containing acrylonitrile and styrene) and the polar groups of the epoxy glue (such as hydroxyl groups and epoxy groups). For lead, due to its low surface energy and inert oxide layer, the bonding strength is average (about 2 - 10 MPa), and the bonding performance needs to be improved by modifying the epoxy glue (such as adding toughening agents) to ensure that the lead pole column and the insert are tightly sealed, and to ensure the internal sealing of the battery cell after the pole group head and the sealing bag are encapsulated. The epoxy glue sealing layer solves the interface sealing problem between the ABS insert and the lead pole column. The epoxy glue chemically bonds with the polar surface of ABS to form a stable seal. The modified colloid adapts to the low surface energy characteristics of lead to prevent debonding. The bonding strength of the epoxy glue with ABS and lead and its principle mainly depend on the surface properties of the materials and the interfacial interactions. For ABS, the epoxy glue usually exhibits a medium to high bonding strength, and it is difficult to peel the cured epoxy glue from ABS, which benefits from the hydrogen bonding or dipole interaction formed between the polar surface of ABS (containing acrylonitrile and styrene) and the polar groups of the epoxy glue (such as hydroxyl groups and epoxy groups). For lead, due to its low surface energy and inert oxide layer, the bonding strength is low to medium, and the bonding performance needs to be improved by adding toughening agents. Adding organosilicon and silane compounds to the epoxy glue can enhance acid resistance and flexibility. Organosilicon enhances the elasticity of the colloid to adapt to temperature deformation, and silane compounds react with the acidic environment to form an inert layer to delay corrosion, which can effectively extend the service life of lead-acid batteries.

[0014] For the pole group head of a single lead-acid battery, the two side edges of the main body part are rounded. Through the rounding treatment of the edges of the main body part, it is avoided that the soft-packing material is punctured by the sharp edges of the main body part during the heat-sealing process, resulting in the leakage of the electrolyte package being damaged.

[0015] The advantages of the present invention are as follows: It adopts a composite structure of a non-polar PP main body and a polar ABS insert. The PP main body is heat-seal compatible with the sealed bag, and the ABS insert is strongly bonded to the lead pole column through a polar adhesive, solving the problem that traditional mechanical extrusion sealing cannot be used due to insufficient space in high aspect ratio electric cores. In combination with a pH-responsive adhesive, it automatically releases repair monomers to fill cracks during electrolyte acid etching (pH ≤ 3), reconstructs the borate network, and realizes interface self-repair; the convex texture (depth 0.5 - 1 mm) on the surface of the main body provides a gradient pressure resistance capacity of 40 - 90 kPa, and the annular cavity glue storage structure ensures uniform distribution and curing of the glue, forming a triple sealing barrier of "heat-seal interface + bonding interface + dynamic repair"; the aspect ratio design improves the heat dissipation efficiency during formation, reduces the internal temperature of the electric core, the acid resistance range of the PP material is better than that of traditional ABS, and in combination with a modified epoxy adhesive (containing organosilicon / silane), it delays the corrosion of the lead pole column and extends the battery cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0017] Figure 1 Schematic diagram of the installation of the pole group head of the present invention on the electric core.

[0018] Figure 2 Schematic diagram of the structure of the electric core of the present invention.

[0019] Figure 3 Schematic diagram of the bottom of the pole group head of the present invention.

[0020] Figure 4 Data graph of the impact resistance experiment of the ABS sample in Example 2 of the present invention.

[0021] Figure 5 Aspect ratio - formation temperature difference curve of the electric core in Example 2 of the present invention.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS: 1 - main body, 2 - insert, 3 - electric core, 4 - sealed bag, 11 - convex texture, 12 - reinforcing rib, 21 - annular outer cavity, 22 - cylindrical inner cavity, 23 - positioning rib, 31 - lead pole column. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] First, the concepts involved in the present application will be described in conjunction with the accompanying drawings. It should be noted here that the descriptions of the following concepts are only for making the content of the present application easier to understand, and do not represent a limitation on the protection scope of the present application; at the same time, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0025] Embodiment 1: Referring to the attached Figure 1 As shown, a pole group head of a single lead-acid battery includes a main body member 1 and an embedded member 2. The material of the main body member 1 is a non-polar polymer material, and the material of the embedded member 2 is a polar polymer material. The main body member 1 and the embedded member 2 are tightly bonded, and the pole group head is installed on the battery cell 3. A sealing bag 4 is covered outside the battery cell 3, and the sealing bag 4 is also made of a non-polar polymer material. Based on the requirements of the heat sealing process, the main body member 1 needs to be made of a non-polar polymer material to achieve heat sealing combination with the sealing bag 4. Since the pole group head of the present invention has a structural feature of a relatively high aspect ratio of width to thickness, the traditional mechanical extrusion sealing (using the pressing force between the lead pole column 31 and the non-polar polymer material to achieve sealing) cannot be applied due to insufficient space. Therefore, a polar adhesive needs to be selected to fix the lead pole column 31. For this reason, the embedded member 2 (polar polymer material) is provided to provide a bonding interface with the lead pole column 31 and ensure that the embedded member 2 and the main body member 1 remain in a tightly bonded state.

[0026] Referring to the attached Figure 1 As shown, for a pole group head of a single lead-acid battery, the width of the main body member 1 is L, the thickness is W, and the aspect ratio of width to thickness L / W≥8. The aspect ratio of width to thickness L / W≥8 is used to adapt to and install a battery cell 3 with an aspect ratio of width to thickness L / W>8 greater than 8. When the aspect ratio of width to thickness of the battery cell 3 is larger, the battery cell 3 will be relatively thinner, so that the water bath can more effectively take away the heat generated by the charge and discharge of the battery cell 3 during the formation process; under appropriate width and thickness conditions, the larger the aspect ratio of width to thickness of the battery cell 3, the lower the internal temperature of the battery cell 3 during the formation process.

[0027] Referring to the attached Figure 1 and the attached Figure 3As shown in the figure, a pole group head of a single lead-acid battery has raised textures 11 on both side surfaces of the main body part 1. The raised textures 11 are parallel lines, and the number of lines is at least one, and the depth range of the lines is 0.5 mm - 1 mm. The pole group head of the present invention is installed on the battery cell 3, and a heat-sealing process is used to combine the sealing bag 4 with the pole group head to wrap the battery cell 3. By limiting the depth range of the raised textures 11, the contact area between the sealing bag 4 and the pole group head is optimized, ensuring that the raised textures 11 can both enhance the bonding force and will not cause a decrease in material strength due to excessive depth, balancing the sealing performance and structural reliability. When the raised texture 11 is one, two, or three, the leak-free pressure resistance values between the sealing bag 4 and the pole group head are 40 kPa, 70 kPa, and 90 kPa respectively. A single texture meets the basic sealing requirements, and multiple textures provide redundant sealing protection, and users can flexibly select the design specifications according to the battery working conditions.

[0028] Refer to the attached Figure 1 As shown in the figure, a pole group head of a single lead-acid battery has a reinforcing rib 12 structure on the surface of the main body part 1. The anti-deformation ability of the main body part 1 is improved through the reinforcing rib 12 structure, and the integrity of the sealing interface is guaranteed. The reinforcing rib 12 structure can disperse the stress generated during the encapsulation process, prevent the main body part 1 from warping, and avoid sealing failure caused by material fatigue after long-term use.

[0029] Refer to the attached Figure 3 As shown in the figure, a pole group head of a single lead-acid battery has an annular outer cavity 21 inside the insert 2, a positioning rib 23 is arranged inside the annular outer cavity 21, and a through cylindrical inner cavity 22 is arranged in the middle of the insert 2. The insert 2 constructs a multi-level sealed cavity structure, the annular outer cavity 21 and the cylindrical inner cavity 22, to realize the separation of the conductive and sealing functions. The annular outer cavity 21 serves as a glue storage space to ensure that the glue is evenly distributed along the surface of the insert 2, and the positioning rib 23 plays a guiding and limiting role.

[0030] Refer to the attached Figure 1 and the attached Figure 2 As shown in the figure, a pole group head of a single lead-acid battery has a lead pole column 31 on the battery cell 3, and the lead pole column 31 cooperates with the cylindrical inner cavity 22. Through the cooperation of the lead pole column 31 and the cylindrical inner cavity 22, a conductive path is established and the welding port of the lead pole column 31 is reserved. The lead pole column 31 and the cylindrical inner cavity 22 are tightly fitted to prevent acid solution from penetrating into the pole group. Before the pole group head is installed on the battery cell 3, a certain amount of sealing glue is first added to the cylindrical inner cavity 22 and the annular outer cavity 21. The lead pole column 31 of the battery cell 3 cooperates with the cylindrical inner cavity 22 filled with glue, and the internal sealing glue is extruded into the annular outer cavity 21. After the glue solidifies, the lead pole column 31 is fixed.

[0031] Refer to the attached Figure 1As shown in the figure, a pole group head of a single lead-acid battery, the material of the main body 1 is polypropylene, and the material of the embedded part 2 is ABS. The parts of the pole group head in contact with the sealing bag 4 are all polypropylene (PP). Under certain temperature conditions, the heat sealing combination with the sealing bag 4 has a high bonding force, making it difficult for the two to peel off, ensuring the sealing of the internal main body of the battery cell 3. The PP material can withstand a pH range of about 2 - 12 at 80 °C, and the range is larger than that of the ABS material used for the cover of the ordinary lead-acid battery cell (the pH tolerance range is about 4 - 10), and it has better acid and corrosion resistance. A single-layer or multi-layer raised texture 11 structure is designed on the contact surface between the pole group head and the sealing bag 4 to increase the heat sealing contact surface area and improve the bonding force between the two. The material of the contact surface between the embedded part 2 and the lead pole 31 inside is ABS plastic. ABS contains acrylonitrile polar groups. Compared with non-polar plastics such as PE and PP, the surface energy of ABS is relatively high, about 36 - 42 mN / m. It is easier to form physical adsorption or chemical bonding with the lead element in the lead-acid battery. Other plastics such as PP are completely non-polar materials with low surface energy and weak bonding force with metals in the natural state. Therefore, the contact part between the embedded part 2 and the lead pole 31 uses ABS polar material. Further, the strength of the ABS material is higher than that of PP, which can play a better protective role for the lead pole 31. Compared with the traditional integrated pole group head structure, the main body 1 and the embedded part 2 are assembled using two different materials, ABS and PP, which can give full play to the advantages of the two materials.

[0032] Refer to the appendix Figure 1 As shown in the figure, a pole group head of a single lead-acid battery, a pH-responsive adhesive is added to the bonding interface between the main body 1 and the embedded part 2. The pH-responsive adhesive contains acid-responsive microcapsules. The components of the pH-responsive adhesive include borate bond prepolymer, epoxy acrylic hybrid resin, TPO-L, and dicumyl peroxide. The shell material of the acid-responsive microcapsule is polymethyl methacrylate-co-maleic anhydride, and the core material is pentaerythritol triacrylate. The dynamic borate bonds in the dynamic borate bond prepolymer will trigger recombination during the acid etching of the electrolyte (pH ≤ 3). The microcapsule shell selectively ruptures when the H + concentration > 0.15 mmol / L, releasing the repair monomer to quickly fill the interface microcracks. At the same time, the dynamic reconstruction of the borate network enhances the molecular entanglement at the non-polar polymer / polar polymer interface, realizing the dual effects of self-repair and mechanical enhancement in the acid etching environment. The epoxy acrylic hybrid resin provides a rigid skeleton for the adhesive and forms a dense protective layer at the same time, slowing down the erosion rate of the electrolyte; TPO-L is a UV light-triggered curing agent, and dicumyl peroxide is a heat-triggered curing agent. The two work together to completely cure the adhesive in the gradient curing process, ultimately ensuring the tight sealing of the bonding interface between the embedded part 2 and the main body 1, and ensuring the internal sealing of the battery cell 3 after the pole group head and the sealing bag 4 are encapsulated.

[0033] Refer to the appendix Figure 1As shown in the figure, for the pole group head of a single lead-acid battery, the contact surface between the lead pole 31 and the insert 2 is sealed with epoxy glue. The epoxy glue contains acid-resistant modification components of long-chain alkyl organosilicon compounds and tetraethoxysilane. The material of the insert 2 is ABS. The epoxy glue and ABS usually exhibit relatively high bonding strength (about 5 - 20 MPa). The hydrogen bonds or dipole interactions are formed between the polar surface of ABS (containing acrylonitrile and styrene) and the polar groups of the epoxy glue (such as hydroxyl groups and epoxy groups). For lead, due to its low surface energy and inert oxide layer, the bonding strength is average (about 2 - 10 MPa). It is necessary to modify the epoxy glue (such as adding toughening agents) to improve the bonding performance, so as to ensure that the lead pole 31 and the insert 2 are tightly sealed, and to ensure the internal sealing performance of the battery cell 3 after the pole group head and the sealing bag 4 are encapsulated. The interface sealing problem between the ABS insert 2 and the lead pole 31 is solved through the epoxy glue sealing layer. The epoxy glue is chemically bonded to the polar surface of ABS to form a stable seal. The modified colloid adapts to the low surface energy characteristics of lead to prevent glue peeling. The bonding strength of the epoxy glue with ABS and lead and its principle mainly depend on the surface properties of the materials and the interfacial interactions. For ABS, the epoxy glue usually exhibits medium to high bonding strength. It is difficult to peel the epoxy glue from the ABS after curing, which benefits from the hydrogen bonds or dipole interactions formed between the polar surface of ABS (containing acrylonitrile and styrene) and the polar groups of the epoxy glue (such as hydroxyl groups and epoxy groups). For lead, due to its low surface energy and inert oxide layer, the bonding strength is low to medium, and it is necessary to add toughening agents to improve the bonding performance. Adding organosilicon and silane compounds to the epoxy glue can improve the acid resistance and flexibility. The organosilicon enhances the elasticity of the colloid to adapt to temperature deformation. The silane compound reacts with the acidic environment to generate an inert layer to delay corrosion, which can effectively extend the service life of the lead-acid battery.

[0034] Example 2: Step 1: Preparation of the pole group head structure Refer to the appendix Figure 1 As shown in the figure, prepare the main body 1 and the insert 2. The main body 1 is injection-molded with PP, with a thickness of 2.5 mm. Single-strip raised textures 11 are processed on both sides of the surface, and the texture depth is 0.8 mm. The insert 2 is made of ABS material, and the width of the annular outer cavity 21 is 2.0 mm, which is used to store the sealing glue.

[0035] Step 2: Preparation and coating of the adhesive Prepare a pH-responsive adhesive. Its ingredients include: dynamic borate prepolymer (60-65wt%), acid-responsive microcapsules (15wt%, shell material: polymethyl methacrylate-co-maleic anhydride), epoxy-acrylic hybrid resin (20-25wt%), TPO-L (2.5-3wt%), and dicumyl peroxide (1.5-2wt%). Apply the adhesive using a three-roll transfer mechanism to a thickness of 18-23μm. Add 0.8-1.2wt% of a benzotriazole derivative to enhance pH sensitivity. Inject the prepared adhesive into the interface between main component 1 and insert 2.

[0036] Step 3: Gradient curing process execution First, a 385nm UV light source (115mW / cm²) was used to vertically irradiate the adhesive layer for 11 seconds, achieving a surface crosslinking degree of over 83%. Within 0.5 seconds, the system switched to mid-wave infrared radiation, controlling the peak temperature at 75±3°C for 30 seconds to complete deep cationic polymerization, ensuring a ≤8% difference in curing between the inner and outer layers.

[0037] Step 4: Assemble the pole group head and lead pole Refer to the attached Figure 1 , Attachment Figure 3 As shown, the lead pole 31 is inserted into the cylindrical inner cavity 22 of the insert 2. The annular outer cavity 21 is pre-injected with 1.5 mL of epoxy sealant, and the gap is evenly filled with the glue by squeezing.

[0038] Step 5: Sealing and heat sealing Refer to the attached Figure 1 As shown, a heat seal is performed on the contact surface between the main body 1 and the PP sealing bag 4. The heating plate temperature is set to 180°C and the pressure is 0.3 MPa for 5 seconds. The 0.8 mm deep raised texture 11 on the surface of the main body 1 increases the heat seal contact area by 40%, increasing the seal strength to 90 kPa. The sealing bag 4 and the main body 1 are sealed together, ultimately completely covering the battery cell 3.

[0039] Step 6: Performance Verification Test ABS protection performance test for lead pole 31: ABS samples were tested with a width of 10mm, a thickness of 4.05mm, a gauge length of 50mm, and a tensile speed of 200mm / min. The tensile strength of the ABS samples was greater than 50MPa, and the impact strength was greater than 20KJ / m 2 , has good impact resistance and can better protect the lead pole 31. The test results are shown in Table 1 and Appendix Figure 4 shown.

[0040] Table 1. Strength test results

[0041] Sealing test: When there are one, two or three raised textures 11 on the surfaces of both sides of the pole group head, it is guaranteed that there is no leakage between the sealing bag 4 and the pole group head under pressures of 40kPa, 70kPa and 90kPa; Mechanical strength test: Apply 10N·m torque to the ABS support layer to verify that there is no deformation; Environmental resistance test: The initial temperature is 25℃, dropped to -40℃, kept warm for 6 hours, then raised to 120℃, kept warm for 6 hours. The time from -40℃ to 120℃ is set to 90 minutes. After 100 cycles, there is no structural deformation and the integrity meets the protection requirements. Acid resistance test: The electrode group head was immersed in a sulfuric acid solution with a pH of 1 for 200 cycles. The pH test paper dipped in pure water was used to detect the lead electrode 31 position and the interface between the main part 1 and the embedded part 2. It was found that the pH test paper did not change color, and there was no crack or electrolyte penetration on the interface.

[0042] Cell 3 width-to-thickness ratio test: refer to the attached Figure 5 As shown, three cells assembled with three different electrode group heads with different aspect ratios were acid-filled using an acid filling machine. Each electrode group head had the same aspect ratio (L / W) as the corresponding electrode group head, with an acid density of 1.26 g / cm³ (25°C). The acid filling volume was 290 g. The three cell aspect ratios (L / W) were as follows: ① Soft-packed single cells of the present invention, aspect ratio = 12.25 (two groups); ② Soft-packed single cells of the present invention, aspect ratio = 8 (two groups); ③ Traditional single cells, aspect ratio = 2.4. Twelve cells of each type were acid-filled. After acid filling, each cell was placed in the same formation water bath set to 25°C. The cell temperature during formation was recorded using a paperless recorder. Two temperature probes were installed on each cell with three different aspect ratios, each attached to the center of the cell's side surface to ensure accurate temperature monitoring. All three cells were charged and discharged using a "modular 85h" formation process. While the charge and discharge process was running, a paperless recorder was used to record temperature data. The formation temperature difference curve shows that the larger the cell width-to-thickness ratio, the lower the maximum temperature during the formation process. When the cell width-to-thickness ratio was 12.25, the maximum temperature during the formation process was only 38.2°C; when the modular width-to-thickness ratio was 8, the maximum temperature during the formation process was 45.1°C; and when the cell width-to-thickness ratio was 2.4, the maximum temperature during the formation process was 52.3°C. The experimental results show that when the width-to-thickness ratio of cell 3 is larger, cell 3 becomes relatively thinner, allowing the water bath to more effectively remove the heat generated by the cell charge and discharge during the formation process. Under appropriate width and thickness conditions, a larger width-to-thickness ratio of cell 3 results in a lower internal temperature during the formation process.

[0043] It should also be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application. Unless otherwise clearly specified and defined, terms such as "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0044] The above-described embodiments and / or implementation manners are only used to illustrate the preferred embodiments and / or implementation manners for implementing the technology of the present invention, and do not impose any formal restrictions on the implementation manners of the technology of the present invention. Any person skilled in the art, without departing from the scope of the technical means disclosed in the content of the present invention, may make some modifications to other equivalent embodiments, but should still be regarded as the same technology or embodiment as the present invention in essence. In this article, specific examples are used to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. The above is only the preferred implementation manner of the present application. It should be noted that due to the limitation of language expression and objectively existing infinite specific structures, for those of ordinary skill in the art, without departing from the principle of the present application, several improvements, refinements or changes can also be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should all be regarded as the protection scope of the present application.

Claims

1. The pole group head of a single lead-acid battery, characterized in that: It includes a main body part (1) and an embedded part (2). The material of the main body part (1) is a non-polar polymer material, and the material of the embedded part (2) is a polar polymer material. The main body part (1) and the embedded part (2) are tightly bonded, and the pole group head is installed on the battery cell (3).

2. The pole group head of a single lead-acid battery according to claim 1, characterized in that: The width of the main body part (1) is L, and the thickness is W, and the width-to-thickness ratio L / W ≥ 8.

3. The pole group head of a single lead-acid battery according to claim 1, characterized in that: There are raised textures (11) on both surfaces of the main body part (1). The raised textures (11) are parallel lines, and the number of lines is at least one, and the depth range of the lines is 0.5 mm - 1 mm.

4. The pole group head of a single lead-acid battery according to claim 1, characterized in that: There is a rib (12) structure on the surface of the main body part (1).

5. The pole group head of a single lead-acid battery according to claim 1, characterized in that: There is an annular outer cavity (21) inside the embedded part (2), there is a positioning rib (23) inside the annular outer cavity (21), and there is a through cylindrical inner cavity (22) in the middle of the embedded part (2).

6. The group head of a single lead-acid battery according to claim 5, characterized in that: There is a lead pole column (31) on the battery cell (3), and the lead pole column (31) and the cylindrical inner cavity (22) cooperate with each other.

7. The pole group head of a single lead-acid battery according to claim 6, characterized in that: The material of the main body part (1) is polypropylene, and the material of the embedded part (2) is ABS.

8. The pole group head of a single lead-acid battery according to claim 7, characterized in that: The contact surface between the lead pole column (31) and the embedded part (2) is sealed with an epoxy adhesive, and the epoxy adhesive contains acid-resistant modified components of long-chain alkyl organosilicon compounds and tetraethoxysilane.

9. The pole group head of a single lead-acid battery according to claim 1, characterized in that: A pH-responsive adhesive is added to the bonding interface between the main body part (1) and the embedded part (2). The pH-responsive adhesive contains acid-responsive microcapsules, and the components of the pH-responsive adhesive include a borate bond prepolymer.

10. The group head of a single lead-acid battery according to claim 9, characterized in that: The shell material of the acid-responsive microcapsule is poly(methyl methacrylate-co-maleic anhydride), and the core material is pentaerythritol triacrylate.

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