Current collector structure and battery pack

Abstract

Current collector structure, characterized in that it comprises a positive current collector (1), wherein the positive current collector comprises a current collector body (11) and a current collector exit lug (12) which are connected to each other; wherein the current collector body (11) is provided with a central underflow hole (13) which extends through the current collector body (11) in the thickness direction thereof, and an entire surface of a surface of the current collector body (11) in the thickness direction is a welding surface for welding to a positive lug of a coil core.

Description

Technical FieldThe present disclosure relates to the technical field of current collectors, and more particularly, to a current collector structure and a battery pack.Prior ArtCompared with conventional batteries such as nickel-cadmium and lead-acid batteries, lithium-ion batteries offer advantages such as high energy density, high operating voltage, low self-discharge rate, long life, high charging and discharging efficiency, wide operating temperature range, and low environmental pollution. At present, lithium ion batteries are widely used in mobile phones, notebooks, and other 3C devices, as well as new energy vehicles, and also have wide applications in civil aircraft, drones, space probes, and other areas of aerospace.Currently, laser welding is often used with lithium ion batteries to weld the positive current collector and the exposed positive tab of the coil core. However, the positive current collector forming process in the related technology is relatively complicated, with arcuate, flange-shaped, and other structures, and there are multiple protrusions and one or more of the slot structures, resulting in a small welding area that is susceptible to problems in welding, enabling potential improvements.Disclosure of Utility ModelAn object of the present disclosure is to provide a current collector structure having a large welding area to reduce the problem of poor welds.In a first aspect, in the present disclosure, there is provided a current collector structure including a positive current collector, the positive current collector including a current collector body and a current collector lead-out tab connected to each other.The current collector body is provided with a central underflow hole extending through the current collector body in the thickness direction, and the entire surface of the current collector body in the thickness direction is a welding surface for welding to a positive tab of a coil core.In one implementation, one or more circumferential underflow holes are spaced along a circumference of the current collector body on the outside.In one implementation, the current collector body is provided with an inner underflow hole in the thickness direction of the current collector body, and the inner underflow hole is disposed on a side of the central underflow hole.In one implementation, a welding surface of the current collector body is welded by laser spin welding or laser spot welding to form one or more laser spin welds or one or more laser spot welds.In one implementation, one or more of the laser weld seams form an outer and an inner weld boundary. The outer screw welding boundary and the inner screw welding boundary are circular and provided concentrically with the central underflow hole, and a center of the circle of the inner underflow hole is located on the outer screw welding boundary.Alternatively, one or more of the laser spot welds may form an outer and an inner spot weld boundary. The outer and inner spot welding boundaries are circular and concentric with the central underflow hole, and a center of the circle of the inner underflow hole is on the outer spot welding boundary.In one implementation, two surfaces of the current collector body in the thickness direction of the current collector body are provided with a protrusion and a corresponding groove, the groove and the protrusion being aligned and formed in the same shape, the protrusion being disposed on a welding surface, and at least a part of the protrusion extending up to the edges of the current collector body.In one implementation, one or more of the protrusions are provided that are arc-shaped, with two ends of each of the protrusions extending to an edge of the current collector body to form a positive current collecting region around an edge portion of the current collector body, and one or more of the circumferential underflow holes are provided on one or more of the positive current collecting regions, respectively.In one implementation, the current collector body is provided with one or more of the positive electrolyte electrode infiltration channels through the current collector body in its thickness direction.In one implementation, one or more of the positive electrolyte electrode infiltration channels are distributed in an annular array centered about the central underflow hole; and a region between the central underflow hole and one or more of the positive electrolyte electrode infiltration channels is welded by laser screw welding or laser spot welding to form one or more laser screw welds or one or more laser spot welds.In one implementation, one or more of the laser weld seams form an outer and an inner weld boundary. The outer and inner screw weld restrictions are circular and concentric with the central underflow hole, and one or more of the positive electrolyte electrode infiltration channels are provided outside the outer screw weld restriction.Alternatively, one or more of the laser spot welds may form an outer and an inner spot weld boundary. The outer and inner spot welding boundaries are circular and concentric with the central underflow hole, and one or more of the positive electrolyte electrode infiltration channels are provided outside the outer spot welding boundary.In one implementation, two surfaces of the current collector body in the thickness direction of the current collector body are provided with a protrusion and a corresponding groove, the groove and the protrusion being aligned and formed in the same shape, and the protrusion being disposed on a welding surface.One or more of the protrusions are provided and have an arc shape, two ends of each of the protrusions extend to an edge of the current collector body, and an infiltration channel for positive electrolyte electrodes is provided between two adjacent protrusions.In an implementation, the current collector structure further includes a negative current collector, wherein the negative current collector is provided with a center solder set at a center of a surface in a thickness direction thereof, the solders of the center solder set are distributed in at least two rows in a first direction, the solders in each row are distributed at an interval, and the solders in adjacent rows are obliquely aligned.In one implementation, the negative current collector is provided with one or more of the infiltration channels for negative electrolyte electrodes through the negative current collector in the thickness direction thereof.In one implementation, one or more of the negative electrolyte electrode infiltration channels are distributed in an annular array centered on the central braze set; and a region between two adjacent negative electrolyte electrode infiltration channels is welded by laser welding or laser spot welding to form one or more laser screw welds or one or more laser spot welds.In a second aspect, the present disclosure also provides a battery pack including the above current collector structure.In summary, the technical solutions of the present disclosure have the following positive effects:According to the embodiments of the present disclosure, due to the presence of a plurality of protrusions and one or more of the grooves in the present current collector, it is not possible to weld to the protrusions and grooves, which may result in a smaller welding area. However, the present current collector structure is simplified. In addition to setting the required central underflow holes, an entire surface of the current collector body itself may be used for welding to the positive tabs of the coil core. An increase in the welding area can effectively result in an increase in the contact area with the positive tabs of the coil core, which in turn leads to an increase in the current-carrying region, whereby the power rate of the tabs is effectively improved, the current capacity of the battery is increased and the heat generation is reduced. Moreover, the full-area welding technology is applied to the current collector body, which promotes the welding stability of the current collector structure and reduces the occurrence of poor welds.Brief Description of the DrawingsFIG. 1 is a schematic plan view of the current collector structure of Embodiment I of the present disclosure; FIG. 2 is a sectional view of A-A in FIG. 1 ; FIG. 3 is a schematic plan view of the laser screw welding in the current collector structure of Embodiment I of the present disclosure; FIG. 4 is a schematic plan view of the laser spot welds in the current collector structure of Embodiment I of the present disclosure; FIG. 5 is a schematic plan view of a surface having a groove structure in the current collector structure of Embodiment II of the present disclosure; FIG. 6 is a sectional view of B-B in FIG. 5 ; FIG. 7 is a schematic plan view of a surface of a protrusion structure in the current collector structure of Embodiment II of the present disclosure; FIG. 8 is a sectional view of C-C in FIG. 7 ; FIG. 9 is a schematic plan view of the current collector structure of Embodiment III of the present disclosure; FIG. 10 is a schematic plan view of the current collector structure of Embodiment IV of the present disclosure; FIG. 11 is a schematic plan view of the current collector structure of Embodiment V of the present disclosure; and FIG. 12 is another schematic plan view of the current collector structure of Embodiment V of the present disclosure.Indicia: 1 positive current collector; 11 current collector body; 111 positive current collecting areas; 12 current collector lead-out tab; 13 central underflow hole; 14 circumferential underflow hole; 15 inner underflow hole; 16 protrusion; 17 groove; 18 positive infiltration channel for electrolyte; 2 laser weld; 21 outer laser weld boundary; 22 inner laser weld boundary; 3 laser weld; 31 outer spot weld boundary; 32 inner spot weld boundary; 4 negative current collector; 41 central braze set; 42 negative infiltration channel for electrolyte.Embodiment(s)In describing the present disclosure, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "upper", "lower", "inner", "outer" and other orientation or position relationships are based on the orientation or position relationships illustrated in the attached drawings. They are intended merely to facilitate the description of the present disclosure and to simplify the description, but do not indicate or imply that said device or element has a particular orientation or is constructed and operated in a particular orientation. Therefore, they should not be understood as limiting the present disclosure.Hereinafter, the current collector structure and the battery according to the embodiments of the present disclosure will be described with reference to FIGS. 1-12. Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Without conflicts, the following embodiments and the features in the embodiments can be combined with one another.Compared with conventional batteries such as nickel-cadmium and lead-acid batteries, lithium-ion batteries offer advantages such as high energy density, high operating voltage, low self-discharge rate, long life, high charging and discharging efficiency, wide operating temperature range, and low environmental pollution. At present, lithium ion batteries are widely used in mobile phones, notebooks, and other 3C devices, as well as new energy vehicles, and also have wide applications in civil aircraft, drones, space probes, and other areas of aerospace.At present, laser welding is often applied to lithium ion secondary batteries to weld the positive current collector 1 and the exposed positive tab of the coil core. However, the positive current collector forming process in the prior art is relatively complicated, with arcuate, flange-shaped, and other structures, and there are multiple protrusions and one or more of the slot structures, resulting in a small welding area that is susceptible to problems in welding, enabling potential improvements.In view of this, in the embodiments of the present disclosure, a current collector structure is proposed that improves the structure of the positive current collector 1, increases the welding contact area of the positive current collector 1 and the positive tab of the coil core, promotes the welding stability of the positive current collector 1, and reduces the occurrence of bad welds.Various specific embodiments will be described below.Embodiment IReferring to FIGS. 1 to 4, the current collector structure proposed in Embodiment I of the present disclosure includes a positive current collector 1. the positive current collector 1 includes a current collector body 11 and a current collector lead-out tab 12 connected to each other. The current collector body 11 is provided with a central underflow hole 13 extending through the current collector body 11 in the thickness direction, and the entire surface of the current collector body 11 in the thickness direction is a welding surface for welding to a positive tab of a coil core.According to the present embodiment I, due to the presence of a plurality of protrusions and one or more of the grooves in the present current collector, it is not possible to weld to the protrusions and grooves, which may result in a smaller welding area. However, the present current collector structure is simplified. In addition to setting the required central underflow holes 13, an entire surface of the current collector body 11 itself may be used for welding to the positive tabs of the coil core. An increase in the welding area can effectively result in an increase in the contact area with the positive tabs of the coil core, which in turn leads to an increase in the current-carrying region, whereby the power rate of the tabs is effectively improved, the current capacity of the battery is increased and the heat generation is reduced. Moreover, the full-area welding technology is applied to the current collector body 11, which promotes the welding stability of the current collector structure and reduces the occurrence of poor welds. At the same time, the current current collector structure is not only simple in structure, but also leads to improvement in manufacturing efficiency and cost reduction.In particular, the central underflow hole 13 is aligned with the central hole of the coil core, whereby a liquid flow which is as uniform as possible can be ensured. Additionally and optionally, a diameter of the central underflow hole 13 is consistent with that of the central hole of the spool core.Specifically, the current collector lead-out tab 12 is joined to a cap in a cover plate assembly by laser welding, and the current collector body 11 is welded to a positive tab surface of the coil core by laser line welding. Additionally and optionally, the positive current collector 1 consists of aluminum, for example 1060-O-aluminum.Further, as shown in FIGS. 1 to 4, one or more of the circumferential underflow holes 14 are arranged at intervals along a circumference of the current collector body 11 on the outside. According to the present embodiment I, sub-circumferential holes 14 are provided at one side of the current collector body 11. During the injection process, the electrolyte first reaches the current collector body 11 and then enters the coil core through the central underflow hole 13. In the present embodiment, in addition to the center underflow hole 13, the circumferential underflow hole 14 is also provided. Therefore, the electrolyte can simultaneously flow from the central underflow hole 13 and the circumferential underflow hole 14 into the coil core, which can contribute to the improvement of the liquid flow capacity. Additionally and optionally, the shape of the circumferential underflow hole 14 is semicircular. Additionally, in some other embodiments, the circumferential underflow hole 14 may have a square or semi-elongated shape.Specifically, as shown in FIG. 1, two sub-circumferential holes 14 are provided, and the two sub-circumferential holes 14 are provided on an upper side and a lower side of the current collector body 11, respectively.Further, as shown in FIGS. 1 to 4, the current collector body 11 is provided with an inner underflow hole 15 in the thickness direction of the current collector body 11, and the inner underflow hole 15 is disposed on one side of the central underflow hole 13. According to the present embodiment I, inner underflow holes 15 are provided on the current collector body 11. During the injection process, the electrolyte first reaches the current collector body 11 and then enters the coil core through the central underflow hole 13. In the present embodiment, in addition to the center underflow hole 13, the inner underflow hole 15 is also provided. Therefore, the electrolyte can simultaneously flow from the central underflow hole 13 and the inner underflow hole 15 into the coil core, which can contribute to the improvement of the liquid flow capacity. Additionally and optionally, the inner underflow hole 15 is circular. Incidentally, the inner underflow hole 15 may have a square or elongated shape in some other embodiments.Note that, according to the present embodiment I, the entire surface of a current collector body 11 in the thickness direction is a welding surface, which means that, except for the central underflow hole 13, the circumferential underflow hole 14, and the inner underflow hole 15 on the current collector body 11, the remaining surfaces of the current collector body 11 are used for welding to the positive tabs of the coil core.Further, as shown in FIG. 4, a welding surface of the current collector body 11 is welded by laser screw welding to form one or more laser screw welds 2. According to the present embodiment I, since one or more of the laser screw welds 2 can effectively increase the welding area by forming a plurality of circular welded joints between the welded joints of the screw weld, deformation of the current collector body 11 can be suppressed and rigidity of the current collector body 11 can be improved due to increase of the welding area. In addition, the welding energy is uniform, the shape, penetration depth and strength of the welded joints are consistent, the appearance is smooth and pleasing without deformation, and the weld is strong and reliable.Specifically, the one or more of the laser welds 2 form an outer screw weld boundary 21 and an inner screw weld boundary 22, and a center of the circle of the inner underflow hole 15 is located on the outer screw weld boundary 21, The outer screw weld boundary 21 and the inner screw weld boundary 22 are both circular and concentrically provided with the central underflow hole 13. The outer screw weld restrictor 21, the inner screw weld restrictor 22, and the center underflow hole 13 are sequentially arranged from the inside to the outside. Additionally and optionally, inner underflow holes 15 are provided between two adjacent laser spin welds 2.Incidentally, in some other embodiments, as shown in FIG. 3, a welding surface of the current collector body 11 may also be welded by laser spot welding to form one or more laser spot welds 3. Laser spot welding offers advantages such as high speed, high accuracy, low heat input, low deformation of the workpiece, precise control, small spot light, high positioning accuracy, and simple automation.Specifically, one or more of the laser spot welds 3 form an outer spot weld boundary 31 and an inner spot weld boundary 32, and a center of the inner underflow hole 15 is located on the outer spot weld boundary 31. The outer spot welding boundary 31, the inner spot welding boundary 32, and the center underflow hole 13 are sequentially arranged from the inside to the outside. Additionally and optionally, inner underflow holes 15 are provided between two adjacent laser spot welds 3.In the present embodiment of the disclosure, not only a current collector structure but also a battery pack including the above-mentioned current collector structure is proposed.Working Example IIReferring to FIGS. 5 to 8, the current collector structure proposed in Embodiment II of the present disclosure includes a positive current collector 1. the positive current collector 1 includes a current collector body 11 and a current collector lead-out tab 12 connected to each other. The current collector body 11 is provided with a central underflow hole 13 extending through the current collector body 11 in the thickness direction, and the entire surface of the current collector body 11 in the thickness direction is a welding surface for welding to a positive tab of a coil core.According to the present embodiment II, due to the presence of a plurality of protrusions and one or more of the grooves in the present current collector, it is not possible to weld to the protrusions and grooves, which may result in a smaller welding area. However, the present current collector structure is simplified. In addition to setting the required central underflow holes 13, an entire surface of the current collector body 11 itself may be used for welding to the positive tabs of the coil core. An increase in the welding area can effectively result in an increase in the contact area with the positive tabs of the coil core, which in turn leads to an increase in the current-carrying region, whereby the power rate of the tabs is effectively improved, the current capacity of the battery is increased and the heat generation is reduced. Moreover, the full-area welding technology is applied to the current collector body 11, which promotes the welding stability of the current collector structure and reduces the occurrence of poor welds. At the same time, the current current collector structure is not only simple in structure, but also leads to improvement in manufacturing efficiency and cost reduction.In particular, the central underflow hole 13 is aligned with the central hole of the coil core, whereby a liquid flow which is as uniform as possible can be ensured. Additionally and optionally, a diameter of the central underflow hole 13 is consistent with that of the central hole of the spool core.Specifically, the current collector lead-out tab 12 is joined to a cap in a cover plate assembly by laser welding, and the current collector body 11 is welded to a positive tab surface of the coil core by laser line welding. Additionally and optionally, the positive current collector 1 consists of aluminum, for example 1060-O-aluminum.Further, as shown in FIGS. 5 to 8, one or more of the circumferential underflow holes 14 are arranged at intervals along a circumference of the current collector body 11 on the outside. According to the present embodiment II, underflow circumferential holes 14 are provided on one side of the current collector body 11. During the injection process, the electrolyte first reaches the current collector body 11 and then enters the coil core through the central underflow hole 13. In the present embodiment, in addition to the center underflow hole 13, the circumferential underflow hole 14 is also provided. Therefore, the electrolyte can simultaneously flow from the central underflow hole 13 and the circumferential underflow hole 14 into the coil core, which can contribute to the improvement of the liquid flow capacity. Additionally and optionally, the shape of the circumferential underflow hole 14 is semicircular. Additionally, in some other embodiments, the circumferential underflow hole 14 may have a square or semi-elongated shape.Further, as shown in FIGS. 5 to 8, two surfaces of the current collector body 11 in the thickness direction of the current collector body 11 are provided with a protrusion 16 and a corresponding groove 17, the groove 17 and the protrusion 16 are aligned and formed in the same shape, the protrusion 16 is disposed on a welding surface, and at least a part of the protrusion 16 extends up to the edges of the current collector body 11. According to the present embodiment II, by setting the projection 16 as the welding surface, the contact area between the projection 16 and the positive tab of the coil core is large enough, that is, the sufficient welding surface between the current collector body 11 and the positive tab of the coil core can be maintained, and the problem of poor welding can be effectively avoided. At the same time, welding efficiency can also be improved as compared with full-area welding, thereby improving manufacturing efficiency. Moreover, the groove 17 on the surface of the current collector body 11 plays a positioning role between the current collector body 11 and the coil core, which is convenient for the person skilled in the art to observe the position of the protrusion 16 for welding.Further, as shown in FIGS. 5 to 8, one or more of the protrusions 16 are provided which are arc-shaped, both ends of each of the protrusions 16 extend to an edge of the current collector body 11 to form a positive current collecting portion 111 around an edge portion of the current collector body 11, and one or more of the circumferential underflow holes 14 are provided on one or more of the positive current collecting portions 111, respectively. According to the present embodiment II, the sub-circumferential hole 14 contributes to improvement of the liquid flow capacity, and the groove 17 plays a positioning role between the current collector body 11 and the coil core. In order to avoid the problem of poor welding caused by welding the protrusion 16 corresponding to the groove 17, the underflow circumferential hole 14 is not disposed on the groove 17 but provided in the positive current collecting portion 111, which can contribute to improvement of the liquid flow capacity and also ensure a sufficiently large contact area.Specifically, as shown in FIGS. 5 to 8, three protrusions 16 are provided on an upper side, a left side and a lower side of the current collector body 11, and the three protrusions 16 are arranged in an annular configuration with the central underflow hole 13 as a center. Also, three grooves 17 are provided, and the three grooves 17 are also respectively disposed on the upper side, the left side, and the lower side of the current collector body 11, and the three grooves 17 are also respectively disposed in an annular arrangement with the central underflow hole 13 as the center. Accordingly, three positive current collecting regions 111 surrounded by the three protrusions 16 and the three grooves 17 are also provided. In addition, three sub-circumferential holes 14 are also provided, and the three sub-circumferential holes 14 are provided one after another on the three positive current collecting portions 111.In the present embodiment of the disclosure, not only a current collector structure but also a battery pack including the above-mentioned current collector structure is proposed.Embodiment IIIReferring to FIG. 9, the current collector structure proposed in Embodiment III of the present disclosure includes a positive current collector 1. the positive current collector 1 includes a current collector body 11 and a current collector lead-out tab 12 connected to each other. The current collector body 11 is provided with a central underflow hole 13 extending through the current collector body 11 in the thickness direction, and the entire surface of the current collector body 11 in the thickness direction is a welding surface for welding to a positive tab of a coil core.According to the present embodiment III, due to the presence of a plurality of protrusions and one or more of the grooves in the present current collector, it is not possible to weld to the protrusions and grooves, which may result in a smaller welding area. However, the present current collector structure is simplified. In addition to setting the required central underflow holes 13, an entire surface of the current collector body 11 itself may be used for welding to the positive tabs of the coil core. An increase in the welding area can effectively result in an increase in the contact area with the positive tabs of the coil core, which in turn leads to an increase in the current-carrying region, whereby the power rate of the tabs is effectively improved, the current capacity of the battery is increased and the heat generation is reduced. Moreover, the full-area welding technology is applied to the current collector body 11, which promotes the welding stability of the current collector structure and reduces the occurrence of poor welds. At the same time, the current current collector structure is not only simple in structure, but also leads to improvement in manufacturing efficiency and cost reduction.In particular, the central underflow hole 13 is aligned with the central hole of the coil core, whereby a liquid flow which is as uniform as possible can be ensured. Additionally and optionally, a diameter of the central underflow hole 13 is consistent with that of the central hole of the spool core.Specifically, the current collector lead-out tab 12 is joined to a cap in a cover plate assembly by laser welding, and the current collector body 11 is welded to a positive tab surface of the coil core by laser line welding. Additionally and optionally, the positive current collector 1 consists of aluminum, for example 1060-O-aluminum.Further, as shown in FIG. 9, the current collector body 11 is provided with one or more of the positive infiltration passages for electrolyte 18 through the current collector body 11 in the thickness direction thereof. According to the present embodiment III, the positive infiltration passage for electrolyte 18 can result in an increase in the transfer passage of the electrolyte in the cell and the thermal runaway exhaust passage, thereby improving the injection performance and the exhaust gas rate when thermal runaway occurs in the cell.Note that, according to the present embodiment III, the entire surface of one side of the current collector body 11 in the thickness direction is the welding surface, which means that, except for the positive electrolyte infiltration channel 18, all remaining surfaces of the current collector body 11 are used for welding to the positive tab of the coil core.Further, as shown in FIG. 9, one or more of the positive electrolyte infiltration channels 18 are distributed in an annular array centered on the central underflow hole 13. A region between the central underflow hole 13 and one or more of the positive electrolyte infiltration channels 18 is welded by laser spin welding to form one or more laser spin welds 2. According to the present embodiment III, since one or more of the laser screw welds 2 can effectively increase the welding area by forming a plurality of circular welded joints between the welded joints of the screw weld, deformation of the current collector body 11 can be suppressed and rigidity of the current collector body 11 can be improved due to increase of the welding area. In addition, the welding energy is uniform, the shape, penetration depth and strength of the welded joints are consistent, the appearance is smooth and pleasing without deformation, and the weld is strong and reliable.Specifically, as shown in FIG. 9, one or more of the laser weld seams 2 form an outer screw weld boundary 21 and an inner screw weld boundary 22, and the outer screw weld boundary 21 and the inner screw weld boundary 22 are both circular and provided concentrically with the central underflow hole 13. The outer screw welding boundary 21, the inner screw welding boundary 22, and the center underflow hole 13 are sequentially arranged from inside to outside, and one or more of the positive electrolyte electrode infiltration passages 18 are provided outside the outer screw welding boundary 21.Additionally, in some other embodiments, a region between the central underflow hole 13 and one or more of the positive electrolyte infiltration channels 18 may be welded by laser spot welding to form one or more laser spot welds 3. One or more of the laser spot welds 3 form an outer spot weld boundary 31 and an inner spot weld boundary 32, the outer spot weld boundary 31 and the inner spot weld boundary 32 are circular and provided concentrically with the center underflow hole 13, and one or more of the positive electrolyte infiltration channels 18 are provided outside the outer spot weld boundary 31.In the present embodiment of the disclosure, not only a current collector structure but also a battery pack including the above-mentioned current collector structure is proposed.Exemplary Embodiment IVReferring to FIG. 10, the current collector structure proposed in Embodiment IV of the present disclosure includes a positive current collector 1. the positive current collector 1 includes a current collector body 11 and a current collector lead-out tab 12 connected to each other. The current collector body 11 is provided with a central underflow hole 13 extending through the current collector body 11 in the thickness direction, and the entire surface of the current collector body 11 in the thickness direction is a welding surface for welding to a positive tab of a coil core.According to the present embodiment IV, due to the presence of a plurality of protrusions and one or more of the grooves in the present current collector, it is not possible to weld to the protrusions and grooves, which may result in a smaller welding area. However, the present current collector structure is simplified. In addition to setting the required central underflow holes 13, an entire surface of the current collector body 11 itself may be used for welding to the positive tabs of the coil core. An increase in the welding area can effectively result in an increase in the contact area with the positive tabs of the coil core, which in turn leads to an increase in the current-carrying region, whereby the power rate of the tabs is effectively improved, the current capacity of the battery is increased and the heat generation is reduced. Moreover, the full-area welding technology is applied to the current collector body 11, which promotes the welding stability of the current collector structure and reduces the occurrence of poor welds. At the same time, the current current collector structure is not only simple in structure, but also leads to improvement in manufacturing efficiency and cost reduction.In particular, the central underflow hole 13 is aligned with the central hole of the coil core, whereby a liquid flow which is as uniform as possible can be ensured. Additionally and optionally, a diameter of the central underflow hole 13 is consistent with that of the central hole of the spool core.Specifically, the current collector lead-out tab 12 is joined to a cap in a cover plate assembly by laser welding, and the current collector body 11 is welded to a positive tab surface of the coil core by laser line welding. Additionally and optionally, the positive current collector 1 consists of aluminum, for example 1060-O-aluminum.Further, as shown in FIG. 10, the current collector body 11 is provided with one or more of the positive electrolyte electrode infiltration passages 18 through the current collector body 11 in the thickness direction thereof. According to the present embodiment IV, the positive infiltration passage for electrolyte 18 can result in an increase in the transfer passage of the electrolyte in the cell and the thermal runaway exhaust passage, thereby improving the injection performance and the exhaust gas rate when thermal runaway occurs in the cell.Further, as shown in FIG. 10, two surfaces of the current collector body 11 in the thickness direction of the current collector body 11 are provided with a protrusion 16 and a corresponding groove 17, the groove 17 and the protrusion 16 are aligned and formed in the same shape, and the protrusion 16 is disposed on a welding surface. One or more of the protrusions 16 are provided and have an arc shape, two ends of each of the protrusions 16 extend to an edge of the current collector body 11, and a positive infiltration channel for electrolyte 18 is provided between two adjacent protrusions 16. According to the present embodiment IV, the positive electrolyte infiltration passage 18 contributes to improvement of injection performance, and the groove 17 plays a positioning role between the current collector body 11 and the coil core. In order to avoid the problem of poor welding caused by welding the protrusion 16 corresponding to the groove 17, the positive electrolyte infiltration passage 18 is not disposed on the protrusion 16 but provided between two adjacent protrusions 16, which may contribute to improvement in injection efficiency and also ensure a sufficiently large contact area.In the present embodiment of the disclosure, not only a current collector structure but also a battery pack including the above-mentioned current collector structure is proposed.Embodiment VReferring to FIGS. 11 and 12, the current collector structure proposed in Embodiment V of the present disclosure includes a positive current collector 1. the positive current collector 1 includes a current collector body 11 and a current collector lead-out tab 12 connected to each other. The current collector body 11 is provided with a central underflow hole 13 extending through the current collector body 11 in the thickness direction, and the entire surface of the current collector body 11 in the thickness direction is a welding surface for welding to a positive tab of a coil core.According to the present embodiment V, due to the presence of a plurality of protrusions and one or more of the grooves in the present current collector, it is not possible to weld to the protrusions and grooves, which may result in a smaller welding area. However, the present current collector structure is simplified. In addition to setting the required central underflow holes 13, an entire surface of the current collector body 11 itself may be used for welding to the positive tabs of the coil core. An increase in the welding area can effectively result in an increase in the contact area with the positive tabs of the coil core, which in turn leads to an increase in the current-carrying region, whereby the power rate of the tabs is effectively improved, the current capacity of the battery is increased and the heat generation is reduced. With respect to the structural configuration, the full-area welding technology is applied to the current collector body 11, which promotes the welding stability of the current collector structure and reduces the occurrence of poor welds. At the same time, the current current collector structure is not only simple in structure, but also leads to improvement in manufacturing efficiency and cost reduction.In particular, the central underflow hole 13 is aligned with the central hole of the coil core, whereby a liquid flow which is as uniform as possible can be ensured. Additionally and optionally, a diameter of the central underflow hole 13 is consistent with that of the central hole of the spool core.Specifically, the current collector lead-out tab 12 is joined to a cap in a cover plate assembly by laser welding, and the current collector body 11 is welded to a positive tab surface of the coil core by laser line welding. Additionally and optionally, the positive current collector 1 consists of aluminum, for example 1060-O-aluminum.Further, as shown in FIG. 11, the current collector structure further includes a negative current collector 4, the negative current collector 4 is provided with a center solder set 41 at a center of a surface in its thickness direction, the solders of the center solder set 41 are distributed in at least two rows in a first direction, the solders in each row are distributed at an interval, and the solders in adjacent rows are obliquely aligned. The first direction refers to the up and down direction indicated by the coordinate system in FIG. 11.According to the present embodiment V, the current collector structure is simple, and the center of the negative current collector 4 is provided with a unique welding structure of misalignment emboss that maximally ensures the welding area of the negative current collector 4. In addition, the spot welding is performed by resistance welding, thereby forming strong welds with good stability.Further, as shown in FIG. 12, the negative current collector 4 is provided with one or more of the negative infiltration passages for electrolyte 42 through the negative current collector 4 in the thickness direction thereof. Additionally and optionally, four negative electrolyte infiltration channels 42 are provided, and the four negative electrolyte infiltration channels 42 are provided on the top, left side, bottom side, and right side of the negative current collector 4. According to the present embodiment V, while maintaining a sufficient welding area between the negative current collector 4 and the tab, the adjusted negative electrolyte infiltration passage 42 can result in an increase in the transfer passage of the electrolyte in the cell and the thermal breakdown outlet passage, thereby improving the injection efficiency and the discharge rate in the occurrence of the thermal breakdown in the cell.Further, as shown in FIG. 12, one or more of the negative electrolyte infiltration channels 42 are distributed in an annular arrangement centered on a center solder joint set 41, and a region between two adjacent negative electrolyte infiltration channels 42 is welded by laser screw welding to form one or more laser screw welds 2. According to the present embodiment V, since one or more of the laser screw welds 2 can effectively increase the welding area by forming a plurality of circular welded joints between the welded joints of the screw weld, deformation of the current collector body 11 can be suppressed and rigidity of the current collector body 11 can be improved due to increase of the welding area. In addition, the welding energy is uniform, the shape, penetration depth and strength of the welded joints are consistent, the appearance is smooth and pleasing without deformation, and the weld is strong and reliable.Additionally, in some other embodiments, a region between two adjacent negative electrolyte infiltration channels 42 may be welded by laser spot welding to form one or more laser spot welds 3. Laser spot welding offers advantages such as high speed, high accuracy, low heat input, low deformation of the workpiece, precise control, small spot light, high positioning accuracy, and simple automation.In particular, the one or more of the negative electrolyte infiltration channels 42 are circular, a negative infiltration channel boundary is formed by joining the circular centers of one or more of the negative electrolyte infiltration channels 42, and one or more of the laser threaded welds 2 or one or more of the laser spot welds 3 pass through the negative infiltration channel boundary.In the present embodiment of the disclosure, not only a current collector structure but also a battery pack including the above-mentioned current collector structure is proposed.

Claims

A current collector structure characterized by comprising a positive current collector (1), wherein the positive current collector comprises a current collector body (11) and a current collector lead-out tab (12) connected to each other; wherein the current collector body (11) is provided with a central underflow hole (13) extending through the current collector body (11) in a thickness direction thereof, and an entire surface of a surface of the current collector body (11) in the thickness direction is a welding surface for welding to a positive tab of a coil core.The current collector structure according to claim 1, wherein one or more of the circumferential underflow holes (14) are arranged at intervals along a circumference of the current collector body (11) on the outside.The current collector structure according to claim 2, wherein the current collector body (11) is provided with an inner underflow hole (15) in the thickness direction of the current collector body (11), and the inner underflow hole (15) is disposed on a side of the central underflow hole (13).The current collector structure according to claim 3, wherein a welding surface of the current collector body (11) is welded by laser screw welding or laser spot welding to form one or more of the laser screw welds (2) and one or more of the laser spot welds (3).The current collector structure according to claim 4, wherein one or more of the laser screw welds (2) form an outer screw weld boundary (21) and an inner screw weld boundary (22), wherein the outer screw weld boundary (21) and the inner screw weld boundary (22) are circular and provided concentrically with the central underflow hole (13), and a center of circle of the inner underflow hole (15) is disposed on the outer screw weld boundary (21); or wherein one or more of the laser spot welds (3) form an outer spot weld boundary (31) and an inner spot weld boundary (32), the outer spot weld boundary (31) and the inner spot weld boundary (32) are circular and provided concentrically with the central underflow hole (13), and a center of circle of the inner underflow hole (15) is disposed on the outer spot weld boundary (31).The current collector structure according to claim 2, wherein two surfaces of the current collector body (11) in the thickness direction of the current collector body (11) are provided with a protrusion (16) and a corresponding groove (17), the groove (17) and the protrusion (16) are aligned with each other and matched in shape, the protrusion (16) is disposed on a welding surface, and at least a part of the protrusion (16) extends up to the edges of the current collector body (11).The current collector structure according to claim 6, wherein one or more of the protrusions (16) are provided and have an arc shape, two ends of each of the protrusions (16) extend to an edge of the current collector body (11) to form a positive current collecting region (111) around an edge part of the current collector body (11), and one or more of the circumferential underflow holes (14) are provided on one or more of the positive current collecting regions (111), respectively.The current collector structure according to claim 1, wherein the current collector body (11) is provided with one or more of the positive infiltration passages for electrolyte (18) through the current collector body (11) in the thickness direction thereof.The current collector structure of claim 8, wherein one or more of the positive electrolyte infiltration channels (18) are distributed in an annular array centered about the central underflow hole (13), wherein a region between the central underflow hole (13) and one or more of the positive electrolyte infiltration channels (18) is welded by laser spin welding or laser spot welding to form one or more of the laser spin welds (2) and one or more of the laser spin welds (3).The current collector structure of claim 9, wherein one or more of the laser weld seams (2) form an outer screw weld boundary (21) and an inner screw weld boundary (22), the outer screw weld boundary (21) and the inner screw weld boundary (22) are circular and concentrically provided with the central underflow hole (13), and one or more of the positive infiltration passages for electrolyte (18) are provided outside the outer screw weld boundary (21); or wherein one or more of the laser weld seams (3) form an outer spot weld boundary (31) and an inner spot weld boundary (32), the outer spot weld boundary (31) and the inner spot weld boundary (32) are circular and concentrically provided with the central underflow hole (13), and one or more of the positive infiltration passages for electrolyte (18) are provided outside the outer spot weld boundary (31).The current collector structure according to claim 8, wherein two surfaces of the current collector body (11) in the thickness direction of the current collector body (11) are provided with a protrusion (16) and a corresponding groove (17), the groove (17) and the protrusion (16) are aligned with each other and matched in shape, and the protrusion (16) is disposed on a welding surface, one or more of the protrusions (16) are provided and have an arc shape, two ends of each of the protrusions (16) extend to an edge of the current collector body (11), and an infiltration channel for positive electrolyte electrodes (18) is provided between two adjacent protrusions (16).The current collector structure according to claim 1, further comprising a negative current collector (4), the negative current collector (4) is provided with a center solder set (41) at a center of a surface in its thickness direction, the solders of the center solder set (41) are distributed in at least two rows in a first direction, the solders in each row are distributed at an interval, and the solders in adjacent rows are obliquely aligned.The current collector structure according to claim 12, wherein the negative current collector (4) is provided with one or more of the infiltration channels (42) for negative electrolyte electrodes through the negative current collector (4) in the thickness direction thereof.The current collector structure of claim 13, wherein one or more of the electrolyte negative electrode infiltration channels (42) are distributed in an annular array centered on the center solder joint set (41), a region between two adjacent electrolyte negative electrode infiltration channels (42) is welded by laser spin welding or laser spot welding to form one or more of the laser spin welds (2) and one or more of the laser spin welds (3).A battery pack, wherein the battery pack comprises the current collector structure according to any one of claims 1 to 14.

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