Patent Application
20250132350
This application claims priority pursuant to 35 U.S.C. 119 (a) to Chinese Application No. 202322815222.6, filed Oct. 19, 2023, which application is incorporated herein by reference in its entirety.
The present utility model relates to the field of novel battery production, in particular to a battery current collector plate and a battery.
Battery laser welding is a highly precise welding technique that is widely used in battery manufacturing and assembly processes, for example to connect a current collector plate to a rolled core by welding. The principle of laser welding is to use a high-energy laser beam to heat a welding material, so that a surface thereof melts, and forms a stable welded connection after cooling. Compared with conventional resistance welding or ultrasonic welding, laser welding has advantages such as fast welding speed, high weld quality, and not causing thermal damage to surrounding material.
In the course of production, research and practical implementation, the inventors have found that despite the abovementioned advantages of laser welding, it is sometimes difficult to guarantee the result when laser welding a current collector plate to a rolled core; the quality of the weld is less than ideal, and the problem of weld spots not being fused, or not being fully fused, may even occur. The welding speed needs to be increased to compensate, but too fast a welding speed will result in a drop in weld quality. Thus, there is an urgent need to find the cause of poor laser welding quality, as well as a solution.
Furthermore, batteries will sometimes overheat, resulting in explosion of the rolled core, etc. The cause of this phenomenon still needs further research.
One aspect of the present utility model provides a battery current collector plate, with a weld zone of low laser reflectivity provided on the current collector plate, such that a surface of the current collector plate absorbs laser energy more effectively, thereby increasing the efficiency and precision of welding. At the same time, the weld zone of low laser reflectivity can also reduce the temperature and the amount of heat generated during laser welding, thereby safeguarding the performance and stability of a rolled core assembly.
One aspect of the present utility model provides a battery current collector plate; the current collector plate comprises a current collector plate body, the current collector plate body having a first face for contacting an end of a rolled core, and a second face opposite the first face;
In some embodiments, the weld zone is hydrophilic.
In some embodiments, the weld zone (2) is at least a portion of the second face (12) that has undergone a hydrophilic treatment, the hydrophilic treatment comprising applying a plating layer, a spray-coating layer, a dip-coating layer or a bonded layer, performing a plasma treatment, and/or performing an oxidation treatment.
In some embodiments, a material of the plating layer, spray-coating layer, dip-coating layer or bonded layer is selected from an inorganic material, the inorganic material being selected from one or more of magnesium oxide, silicon oxide, zirconium oxide, titanate and magnesium aluminum fluoride;
In some embodiments, an axial hole is provided in a middle part of the current collector plate body, the weld zone being arranged around the axial hole.
In some embodiments, the weld zone is multiple weld zones, which are distributed at an outer side of the axial hole in a centrosymmetric manner.
In some embodiments, the current collector plate further comprises a current-leading plate for leading out current, the current-leading plate being connected to the current collector plate body.
In some embodiments, the current-leading plate also comprises a weld zone.
In some embodiments, the weld zone of the current-leading plate and the weld zone of the second face are located on the same side or opposite sides of the current collector plate.
In some embodiments, the current-leading plate is connected to the current collector plate body by means of a folded current-leading region, the folded current-leading region being provided with a fusible region with a reduced current-conducting area.
In some embodiments, the folded current-leading region comprises a first fold region, a second fold region and a connecting region; the first fold region foldably connects the connecting region and the current-leading plate, and the second fold region foldably connects the connecting region and the current collector plate body.
In some embodiments, the first fold region and/or the second fold region is/are provided with a through-hole, the through-hole extending to a portion adjoining the first fold region and/or the second fold region, wherein the adjoining portion may be the current-leading plate, the connecting region and the current collector plate body;
Another aspect of the present utility model provides a battery, the battery comprising a rolled core and the current collector plate, the current collector plate being connected to an end of the rolled core by laser welding.
In some embodiments, multiple weld spots are formed on the current collector plate by irradiation with laser light, the multiple weld spots being discrete weld spots forming multiple rows.
In some embodiments, multiple weld spots are formed on the current collector plate, the multiple weld spots being consecutive weld spots, and forming a straight line, an S shape or a U shape.
Another aspect of the present utility model provides a method for preparing the current collector plate described above.
In some embodiments, a method for preparing a current collector plate for laser welding comprises: subjecting a second face of a current collector plate body to hydrophilic treatment to form a weld zone.
In some embodiments, the hydrophilic treatment for example comprises the following steps: making up a weld zone inorganic coating; optionally subjecting the second face of the current collector plate body to a passivation treatment, for example polishing or etching, etc.; then putting the inorganic coating on a surface of the second face of the current collector plate body, for example using a method such as film-coating, spray-coating, dip-coating or bonding; then curing the inorganic coating, for example drying for 10-14 hours at a temperature of 80-120° C., such that a dispersion medium volatilizes, to obtain a weld zone formed on the second face of the current collector plate body.
In some embodiments, the inorganic coating is selected from one or more of magnesium oxide, silicon oxide, zirconium oxide, titanate and magnesium aluminum fluoride.
Another aspect of the present utility model provides a method for preparing a battery.
In an embodiment, the current collector plate described above may be arranged at a positive electrode or a negative electrode of the battery.
In an embodiment, the current collector plate described above is arranged at the negative electrode of the battery, and the preparation method specifically comprises the following steps: stacking a casing, a negative electrode current collector plate and a rolled core, and performing a laser welding operation; fitting the first face of the current collector plate body in any one of the embodiments above to a positive electrode end of the rolled core, wherein an axis of the rolled core is aligned with an axial hole of the current collector plate body and tight pressing is performed; subjecting the weld zone of the second face of the current collector plate body to a laser welding operation; and injecting electrolyte into the rolled core.
In an embodiment, the preparation method further comprises: bending a first fold region and a second fold region in opposite directions, so as to fold the current collector plate body and a current-leading plate; covering the top of the current-leading plate with a positive electrode terminal and sealing the battery.
To better understand the above and other objectives, features, advantages and functions of the present utility model, the preferred embodiments shown in the drawings may be referred to. In the drawings, identical reference signs denote identical components. Those skilled in the art should understand that the drawings are intended to clarify schematically preferred embodiments of the present utility model, without limiting the scope of the present utility model in any way, and the various components in the drawings are not drawn to scale.
Before any embodiment is explained in detail, it should be understood that applications of embodiments are not limited to the details of the configurations and arrangements of components expounded in the description below or shown in the drawings. Embodiments may be put into practice or implemented in various ways. The embodiments described here are merely preferred embodiments according to the present utility model; based on these preferred embodiments, those skilled in the art will be able to think of other solutions capable of realizing the present utility model, which likewise fall within the scope of the present utility model.
Unless otherwise defined, all technical and scientific terms used in the present utility model have the same meanings as commonly understood by those skilled in the art. In case of conflict, the present utility model (including definitions) shall prevail. Only exemplary methods and materials are described below; methods and materials similar or equivalent to those described in the present utility model may be used in experiments or tests of the present utility model. The materials, methods and examples disclosed in the present utility model are merely illustrative, and not intended to be limiting. The statement of a numerical range in the present utility model explicitly allows for every intermediate number with the same precision within said range.
In the course of production, research and practical implementation, the inventors found that the problem of reduced weld quality will occasionally occur in the process of laser welding current collector plates. After eliminating a large number of causes, it was found that in an existing laser welding process, slight differences in the laser reflectivity of the current collector plate surface across different batches will result in reflection and scattering of much of the laser energy at the metal surface; consequently, full utilization of the laser energy is not possible, and the problem of weld spots not being fused, or not being fully fused, may even occur, resulting in a drop in production yield.
In response to the above technical problem, the present utility model provides a battery current collector plate, which can avoid the above problems. Now referring to
In general, opposite surfaces of a current collector plate 200 have similar laser reflectivities; to reduce the reflection of laser light for welded surfaces during laser welding, the weld zone 2 with lower reflectivity is used to cover the second face 12, thus achieving the convergence of energy and reducing dissipation, and increasing the stability of the laser welding process, preventing the problems caused by differences in current collector plate surface reflectivity across different batches, and increasing the production yield.
In the present utility model, the first face 11 and the second face 12 are opposite each other; the first face is configured to contact the rolled core 100, while the second face 12 is at the back of the first face 11, and configured to contact an end of an electrode. For details, the illustrative positions in
Any existing usable material may be chosen as a material of the current collector plate; in an embodiment, a material of the current collector plate body 1 is selected from copper, tin or aluminum.
The weld zone 2 is provided in the present utility model so that the laser reflectivity of the current collector plate surface is reduced and substantially the same, preventing a drop in production yield due to deviation across different batches. In an embodiment, the weld zone 2 is hydrophilic; for example, the weld zone 2 is at least a portion of the second face 12 that has undergone a hydrophilic treatment. As a result of subjecting a surface of the second face 12 to hydrophilic treatment to form the weld zone 2, the hydrophilicity thereof is greater than that of a surface (e.g. the second face 12) of the current collector plate body 1, and at the same time, the laser reflectivity is reduced. The hydrophilic treatment is related to the laser reflectivity of the second face 12; in general, a smoother flat surface has lower hydrophilicity (e.g. smooth glass), whereas a rougher flat surface has higher hydrophilicity (e.g. frosted glass). Increasing the hydrophilicity (roughness) of the weld zone by hydrophilic treatment achieves the effect of reducing the laser reflectivity.
In some embodiments, the hydrophilic treatment comprises applying a plating layer, a spray-coating layer, a dip-coating layer or a bonded layer, performing a plasma treatment, and/or performing an oxidation treatment. The weld zone 2 may be provided on the surface of the second face 12 by a known method; generally, materials and/or methods that reduce the laser reflectivity are preferred.
In an embodiment, the hydrophilic coating is insulating, and will not react with electrolyte, and furthermore, will not produce other impurities during welding. Therefore, the hydrophilic surface coating is more preferably an inorganic material treatment layer; an organic material is generally not preferred, due to the fact that it will undergo carbonization and produce impurities during high-temperature welding.
In an embodiment, a material of the plating layer, spray-coating layer, dip-coating layer or bonded layer is selected from inorganic metal materials and inorganic non-metal materials, wherein inorganic metal materials include but are not limited to one or more of the group consisting of the following: magnesium oxide, silicon oxide, zirconium oxide, titanate, magnesium aluminum fluoride, etc.; and inorganic non-metal materials include but are not limited to the group consisting of the following: diatomite, kaolin, glass, ceramic, etc.
The method of measuring the laser reflectivity is known in the art; for example, a reflectivity measuring instrument is used for measurement. In an embodiment, the laser reflectivity of the weld zone 2 is lower than 70% of the laser reflectivity of the first face 11; in a preferred embodiment, the laser reflectivity of the weld zone 2 is lower than 60% of the laser reflectivity of the first face 11; in a more preferred embodiment, the laser reflectivity of the weld zone 2 is lower than 50% of the laser reflectivity of the first face 11; and in a most preferred embodiment, the laser reflectivity of the weld zone 2 is lower than 40% of the laser reflectivity of the first face 11.
In general, if the current collector plate body has not undergone special treatment, the laser reflectivities of the first face 11 and the second face 12 thereof should be the same or essentially the same (differing by preferably ±10%, more preferably ±5%, and further preferably ±2%). Therefore, in the case where the second face 12 is completely covered by the weld zone 2, measurement and comparison of the laser reflectivities of the first face 11 and the weld zone 2 is more convenient and quicker.
The dimensions of the current collector plate may be set according to actual production needs, and adjusted according to the dimensions of the battery. In an embodiment, the current collector plate has a thickness of 0.1-0.5 mm, preferably 0.1-0.3 mm, more preferably 0.15-0.25 mm, and most preferably 0.18-0.22 mm.
The thickness of the weld zone 2 is not subject to any particular requirements, but should not be too thick, in which case penetration by laser light would be affected, and should not be too thin, in which case the absorption of laser light would be affected. In an embodiment, the thickness of the weld zone 2 is less than 10% of the thickness of the current collector plate body 1, preferably less than 8% of the thickness of the current collector plate body 1, more preferably less than 5% of the thickness of the current collector plate body 1, and most preferably less than 3% of the thickness of the current collector plate body 1.
In an embodiment, referring to
In an embodiment, the weld zone may be connected to the end of the rolled core by electric welding or by whole-body welding. Preferably, each weld zone 2 comprises multiple weld spots in an array, multiple discrete weld spots, or multiple consecutive weld spots. A single weld spot in the array is irradiated by laser light, to bind the weld zone 2 to the rolled core by welding. Preferably, the multiple weld spots are consecutive weld spots, forming a straight line, an S shape or a U shape.
In an embodiment, each weld zone 2 comprises 8 or more weld spots, preferably 12 or more weld spots, and more preferably 16 or more weld spots.
Now referring to
In the process of battery assembly, to reduce the height of a battery cap structure and maximize the capacity for active substances, the amount of space occupied by the current-leading plate 3 in the axial direction should be minimized. For example, as shown in
In one configuration of the current-leading plate, as shown in
In some situations, the battery will sometimes overheat, resulting in explosion of the rolled core, etc. It has been found through troubleshooting and experiment that overheating sometimes readily occurs when there is excessive current at the current collector plate, resulting in explosion of the rolled core, etc. To solve this problem, the folded current-leading region is provided with a fusible region with a reduced current-conducting area; the fusible region has increased resistance due to the reduction in the current-conducting area, and therefore heats up and melts through more easily, thus serving a safety function. The present utility model does not impose any specific limitations on the configuration of the fusible region, as long as the abovementioned function can be achieved.
In an embodiment, as shown in
In an embodiment, as shown in
In a preferred embodiment, the first fold region 31 and/or the second fold region 32 is/are provided with a through-hole 34, the through-hole extending to a portion adjoining the first fold region 31 and/or the second fold region 32; for example, the through-hole may span the fold region and the connecting region, or the fold region and the current-leading plate, enabling melt-through at a point of connection.
In an embodiment, as shown in
In a particular embodiment, the first fold region 31 and the second fold region 32, as well as a narrow region extending between the first fold region 31 and the second fold region 32, are present between the current-leading plate 3 and the current collector plate body 1. The first fold region 31 separates the current-leading plate 3 from the narrow region, and the second fold region 32 separates the narrow region from the current collector plate body 1. Thus, the narrow region can form an overcurrent protection device, such as a fusible device, which is integral with the current-leading plate 3 and the current collector plate body 1, such that the narrow region can melt through in response to a current exceeding a predetermined value, and thereby interrupt the current between the current-leading plate 3 and the current collector plate body 1. For example, when the current exceeds a predetermined value (e.g. a rated current of a material forming the narrow region), the narrow region will melt through. In an embodiment, the predetermined value may be 101%, preferably 110%, and more preferably 120% of a nominal rated current of a battery unit.
In the process of battery assembly, to reduce the height of the battery cap structure and maximize the capacity for active substances, it is generally necessary to stack the current-leading plate 3 and the current collector plate body 1. This is achieved by bending in opposite directions at the first fold region 31 and the second fold region 32. In some embodiments, the first fold region 31 and the second fold region 32 each have a bending radius and/or tolerance that allows the current collector plate body 1 and the current-leading plate 3 to deform into an S shape. In some embodiments, the narrow region may be provided with an insulator (e.g. an insulating coating or thin insulating tape) on at least one surface thereof. Insulation of this type is used to prevent short-circuiting between the narrow region and the current collector plate body 1 or the current-leading plate 3.
Now referring to
As shown in
Now referring to
In a particular embodiment, the hydrophilic treatment is performed by forming a weld zone 2 on a surface of the current collector plate body 1, specifically comprising: making up an inorganic coating for forming the weld zone 2, making up a solvent from an alcohol and water in the ratio 1:5-5:1, selecting a mixture of the inorganic metal coating and/or inorganic non-metal coating according to the present utility model and said solvent in a mass ratio of 1:1-1:5, and performing treatment in a constant-temperature water bath at 20° C.-80° C., stirring thoroughly and maintaining the temperature to obtain an inorganic sol coating. A passivating liquid for metal surface treatment is used to subject a second face 12 of the current collector plate body 1 to passivation treatment for 4-8 hours at a temperature of 60° C.-100° C., wherein the passivating liquid for metal surface treatment may be purchased commercially. The inorganic sol coating is loaded on the passivated second face 12, wherein forms of loading include but are not limited to film-coating, spray-coating and dip-coating of the surface of the current collector plate body 1, bonding thereto, etc. Drying is then performed at a temperature of 80-120° C. for 10-14 hours, and the loading and drying steps are repeated 1-3 times to obtain the weld zone 2 covering the second face of the current collector plate body 1. In an embodiment, the thickness of the weld zone 2 is less than 10% of the thickness of the current collector plate body 1, preferably less than 8% of the thickness of the current collector plate body 1, more preferably less than 5% of the thickness of the current collector plate body 1, and most preferably less than 3% of the thickness of the current collector plate body 1.
In an embodiment, the current collector plate described above may be arranged at a positive electrode or a negative electrode of the battery. Now referring to
The above description of various embodiments of the present disclosure is provided to a person skilled in the art for descriptive purposes. The present utility model is not intended to be exclusive or limited to a single disclosed embodiment. Based on the above, a person skilled in the field of the above teaching will understand various substitutes for and variants of the present utility model. Therefore, although some alternative embodiments have been specifically described, a person skilled in the art will understand, or develop with relative ease, other embodiments. The present disclosure is intended to include all alternatives, modifications and variants of the present utility model described here, as well as other embodiments falling within the spirit and scope of the present utility model described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202322815222.6 | Oct 2023 | CN | national |
