A cylindrical battery penetration welding composite structure

Abstract

The utility model discloses a cylindrical battery penetrates and welds composite structure belongs to battery technical field, include: casing, its end portion is equipped with recessing to the inside step portion of the inside, the horizontal portion of step portion is equipped with the liquid injection hole, the current collection disc is equipped with the cavity, the connecting piece, the connecting piece includes first welding portion, first connecting portion, second welding portion, second connecting portion, sealing element, the sealing element edge has the third welding portion of protruding to the inside of casing, wherein, first welding portion of connecting piece is overlapped on the horizontal portion outside of the step portion of casing, second welding portion is overlapped on the current collection disc, and second connecting portion stretches into the cavity of current collection disc. In the utility model, casing only welds with connecting piece. The melting point of connecting piece is lower than that of casing, so when welding, connecting piece can be melted without high-power laser. Can realize the stable connection of casing and current collection disc at the same time, reduces the risk that possibly injures the volume core.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cylindrical battery through-welding composite structure. Background Technology

[0002] In the field of lithium-ion battery chemical energy storage technology, with the surge in demand for high-energy-density lithium-ion / sodium-ion cylindrical batteries in new energy vehicles and energy storage systems, their outstanding mass energy density, excellent intrinsic capacity retention, and superior high-rate discharge characteristics have become key driving forces for the development of the new energy industry. Especially against the backdrop of accelerated iteration of fast-charging technology for power batteries, the shell-to-bottom penetration welding process based on multi-physics coupling faces the following key technical challenges:

[0003] (1) Current technologies generally adopt a composite scheme of nickel-cobalt-manganese ternary cathode material and low alloy steel shell to maximize the energy density of the system. However, due to the inherent high melting point of the steel shell (liquidotherm temperature ≈1500℃) and structural thickness parameters (≥0.6mm), a high power density laser beam (>10^6W / cm²) is required during deep penetration welding to achieve metallurgical bonding at the shell bottom-current collector interface. There is a risk of damaging the battery core during the welding process.

[0004] (2) To achieve low interfacial impedance and suppress Joule heat accumulation under high current conditions (≥3C), current current collectors mostly use graded copper-based composite materials (Cu / Ni-P, melting point ≈1083℃). However, when facing the requirement of penetration welding of high-melting-point steel shells, it is necessary to construct a thermal buffer layer by sacrificing the areal density (increasing to 1.2 ~ 1.5 mm). This compromise design leads to a decrease in the effective volume utilization rate inside the single cell by about 8-12%, while also causing loss of specific energy and an increase in material costs. Utility Model Content

[0005] To address the above issues and overcome the shortcomings of existing technologies, this invention incorporates a connector at the connection between the housing and the current collector, creating a gradient transition layer of heterogeneous materials. The first welding portion of the connector overlaps the outer side of the stepped portion of the housing. Therefore, during welding, the housing and connector can be welded first, followed by welding the connector and the current collector. Specifically, when welding the housing and connector, only the connector needs to be melted, without melting the housing itself. Throughout this welding process, the housing protects the internal structure of the battery from welding interference. This not only ensures the stability of the welding between the housing, connector, and current collector but also saves internal battery space, further reducing battery weight and ensuring battery quality.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] This utility model provides a cylindrical battery through-welding composite structure, including:

[0008] The shell is hollow inside, and its end is provided with a stepped portion that is recessed inward. The horizontal portion of the stepped portion is provided with a liquid injection hole.

[0009] The collector plate is provided with a cavity;

[0010] The connector, from top to bottom and from outside to inside, includes a first welding part that extends horizontally inward, a first connecting part that extends vertically downward, a second welding part that extends horizontally inward, and a second connecting part that extends vertically downward.

[0011] A sealing element, wherein the edge of the sealing element has a raised third welded portion extending toward the inside of the housing, and the sealing element has a positioning hole for positioning on the side away from the housing;

[0012] The first welded part of the connector overlaps the outer side of the horizontal portion of the stepped portion of the housing, the second welded part overlaps the collector plate, and the second connecting part extends into the cavity of the collector plate.

[0013] Furthermore, the thickness of the horizontal portion of the stepped part of the shell is h1;

[0014] The distance from the bottom surface of the first welded part to the bottom surface of the second welded part is h2;

[0015] Wherein, h1 is less than or equal to h2.

[0016] Furthermore, the connection between the first welded portion, the first connecting portion, the second welded portion, and the second connecting portion of the connector is smoothly connected in an arc shape; the thickness values ​​of the first welded portion, the first connecting portion, the second welded portion, and the second connecting portion are t1, t2, t3, and t4, respectively;

[0017] Wherein, t1, t2, t3, and t4 are taken as 0.2mm to 0.4mm.

[0018] Furthermore, the width of the first welded portion of the connector is w1, where w1 is 1.5mm to 3.5mm.

[0019] Furthermore, the width of the second welded portion of the connector is w2, where w2 is 2.0mm to 5.0mm.

[0020] Furthermore, after the second connecting portion of the connector extends into the cavity, its lower end face extends beyond the lower surface of the collector plate by at least 0.1 mm.

[0021] Furthermore, the stepped portion of the housing, the cavity of the collector plate, and the horizontal cross-section of the connector are all circular.

[0022] This utility model has at least the following advantages or beneficial effects:

[0023] (1) In this utility model, the shell and the connector are welded together, with the first welded part of the connector overlapping the outer side of the stepped part of the shell. Since the melting point of the connector is lower than that of the shell, the connector can be melted without a high-power laser during welding, and the shell does not need to be melted. During this welding process, the shell always protects the internal structure of the battery from welding damage. Therefore, while achieving a stable connection between the shell and the connector, the risk of laser energy fluctuations potentially damaging the core can be reduced.

[0024] (2) In this utility model, the material of the connector is consistent with that of the manifold, both being nickel-plated copper, which has a lower melting point than the steel used for the casing. Therefore, compared with the welding of the casing and the manifold in the prior art, the connector and the manifold of this utility model are easier to weld together. In addition, this utility model can ensure the consistency of the weld depth between the connector and the manifold, that is, ensure the effective flow area.

[0025] (3) In this invention, the second welded part of the connector is located outside the current collector. Therefore, during the welding process, only the second welded part of the connector needs to be melted, without melting the current collector. During this welding process, the current collector can protect the internal core of the battery from welding damage. Compared with the prior art, which increases the thickness of the current collector, this invention reduces the risk of welding damage to the core while keeping the thickness of the current collector constant. Therefore, it can improve the utilization rate of the internal space of the battery and reduce the weight of the battery. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 Cross-sectional view of the through-welded composite structure of a cylindrical battery;

[0028] Figure 2 This is a cross-sectional view of the shell structure;

[0029] Figure 3 This is a cross-sectional view of the connector structure;

[0030] Figure 4 This is a cross-sectional view of the collector plate structure;

[0031] Figure 5 This is a cross-sectional view of the sealing component.

[0032] Figure label:

[0033] 1-Shell; 101-Stepped section; 102-Injection port;

[0034] 2-Collector; 201-Cavity;

[0035] 3-Connector; 301-First welded part; 302-First connecting part; 303-Second welded part; 304-Second connecting part;

[0036] 4-Seal; 401-Third weld; 402-Positioning hole. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0040] In this utility model, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of the structural relationship of the various parts or elements of this utility model and do not specifically refer to any part or element in this utility model. They should not be construed as limiting this utility model.

[0041] In this utility model, terms such as "fixed", "connected", and "linked" should be interpreted broadly, indicating that it can be a fixed connection, an integral connection, or a detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. For relevant scientific researchers or technicians in this field, the specific meaning of the above terms in this utility model can be determined according to the specific circumstances, and should not be construed as a limitation of this utility model.

[0042] The embodiments of this utility model will be described in detail below.

[0043] This utility model provides a cylindrical battery through-welding composite structure:

[0044] In this embodiment, the housing 1, the collector 2, the connector 3, and the seal 4 are all cylindrical, frustum-shaped, or disc-shaped.

[0045] Figure 1 A cross-sectional view of the cylindrical battery through-welding composite structure of this utility model is shown. As can be seen from the figure, it mainly consists of four parts:

[0046] Housing 1, which is the battery casing, can protect its internal structure from external impacts and damage;

[0047] Collector plate 2, which is located inside the housing 1, with its upper surface in contact with the housing 1 and its lower surface in contact with the internal winding core of the battery;

[0048] Connector 3 connects housing 1 and collector plate 2, and acts as a transition;

[0049] The sealing element 4 can be inserted into the stepped portion 101 of the housing 1 and welded to the housing 1 to seal the injection hole.

[0050] Specifically, Figure 2 A cross-sectional view of the shell 1 is shown. The shell 1 is a hollow cylindrical shell with a small opening at the top and an open bottom. There is an inwardly recessed stepped portion 101 on the upper surface of the shell 1. A first liquid injection hole 102, which is circular, is provided on the horizontal portion of the stepped portion 101. Furthermore, the thickness of the horizontal portion of the stepped portion 101 of the shell 1 is h1.

[0051] Figure 3 A cross-sectional view of connector 3 is shown. Connector 3 is a hollow, stepped frustum of a cone with a larger diameter at the top end face than at the bottom end face. From top to bottom and from outside to inside, connector 3 consists of a first welding portion 301 extending horizontally inward, a first connecting portion 302 extending vertically downward, a second welding portion 303 extending horizontally inward, and a second connecting portion 304 extending vertically downward. The connections between the first welding portion, the first connecting portion, the second welding portion, and the second connecting portion are smoothly formed in an arc shape.

[0052] The thicknesses of the first welding portion 301, the first connecting portion 302, the second welding portion 303, and the second connecting portion 304 of the connector 3 are t1, t2, t3, and t4, respectively, where t1, t2, t3, and t4 are 0.2mm to 0.4mm. The widths of the first welding portion 301 and the second welding portion 303 are w1 and w2, respectively, where w1 is 1.5mm to 3.5mm and w2 is 2.0mm to 5.0mm.

[0053] Furthermore, the height of the lower surface of the first welded part 301 from the lower surface of the second welded part 303 is h2.

[0054] Furthermore, h1 is less than or equal to h2.

[0055] Figure 4 A cross-sectional view of the current collector 2 is shown. A cavity 201 is provided in the middle of the current collector 2. The inner surface of the stepped portion 101 of the housing 1 is attached to the upper surface of the current collector 2, and the lower surface of the current collector 2 is welded to the tab of the internal winding core of the battery.

[0056] During assembly, the manifold 2 is inserted from the lower opening of the housing 1. The first welding part 301 of the connector 3 overlaps with the horizontal portion of the stepped portion 101 of the housing 1, and the second welding part 303 overlaps with the upper surface of the manifold 2. Subsequently, the first welding part 301 is welded to the horizontal portion of the stepped portion 101 using welding methods such as laser welding; and the second welding part 303 is welded to the manifold 2.

[0057] The casing 1 is made of steel, while the current collector 2 and connector 3 are all made of nickel-plated copper. Therefore, the melting point of the casing 1 is higher than that of the current collector 2 and connector 3. Because the first weld portion 301 is located outside the stepped portion 101, welding only requires melting the first weld portion 301, thus protecting the internal structure of the battery from welding damage. Furthermore, because the second weld portion 303 is located outside the current collector 2, welding only requires melting the second weld portion 303, thus protecting the internal core of the battery from welding damage. Additionally, the identical material of the current collector 2 and connector 3 ensures consistent weld penetration, guaranteeing an effective current flow area.

[0058] After assembly, the first connecting part 302 of the connector 3 serves to fix the housing 1 to the manifold 2; the lower end face of the second connecting part 304 of the connector 3 can extend into the lower surface of the manifold 2 by at least 0.1 mm, which serves to protect the manifold 2 from corrosion damage caused by the injection fluid.

[0059] at last, Figure 5A schematic diagram of the seal 4 is shown. The seal 4 is generally a disc with a third welded portion 401 protruding inwards from the periphery. The seal 4 serves to seal the injection hole 102. When installing the seal 4, it is first snapped onto the stepped portion 101 of the housing 1, and then the third welded portion 401 is fixedly connected to the housing 1 by means of laser welding or other methods.

[0060] When assembling the cylindrical battery through-welding composite structure of this utility model, the following steps are preferred:

[0061] Step 1: Stamp the upper end face of the shell 1 to form a stepped part 101 and a liquid injection hole 102;

[0062] Step 2: Stamping to form connector 3;

[0063] Step 3: Use a laser to weld the first welding part 301 of the connector 3 to the step part 101. The first connecting part 302, the second welding part 303, and the second connecting part 304 pass through the injection hole 102.

[0064] Step 4: Fit the current collector 2 to one end of the copper foil full-pole tab of the core and fix it by laser welding. Then, send it into the inside of the housing 1 from the opening end of the housing 1 to ensure that the upper surface of the current collector 2 can contact the step part 101 and the second welding part 303.

[0065] Step 4: Perform low-power laser penetration welding on the collector plate 2 and the second welding part 303 of the connector 3 to achieve a stable connection;

[0066] Step 5: Continue assembly according to standard production methods;

[0067] Step 6: Snap the seal 4 into the outer shell 1, and then laser weld the seal.

[0068] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cylindrical battery through-welding composite structure, characterized in that, include: The shell (1) is hollow inside and has a stepped part (101) recessed into the inside of the shell (1) at its top. The horizontal part of the stepped part (101) is provided with a liquid injection hole (102). The collector plate (2) is provided with a cavity (201); The connector (3) includes, from top to bottom and from outside to inside, a first welding part (301) extending horizontally inward, a first connecting part (302) extending vertically downward, a second welding part (303) extending horizontally inward, and a second connecting part (304) extending vertically downward. The sealing element (4) has a raised third welded part (401) extending into the housing (1) at its edge. The first welding part (301) of the connector (3) overlaps the outer side of the horizontal part of the stepped part (101) of the housing (1), the second welding part (303) overlaps the collector plate (2), and the second connecting part (304) extends into the cavity (201) of the collector plate (2).

2. The cylindrical battery through-welding composite structure according to claim 1, characterized in that, The thickness of the horizontal portion of the stepped portion (101) of the housing (1) is h1; The distance from the bottom surface of the first welding part (301) of the connector (3) to the bottom surface of the second welding part (303) is h2; Wherein, h1 is less than or equal to h2.

3. The cylindrical battery through-welding composite structure according to claim 1, characterized in that, The connection between the first welding part (301), the first connecting part (302), the second welding part (303), and the second connecting part (304) of the connector (3) is smoothly connected in an arc shape; The thickness values ​​of the first welded part (301), the first connecting part (302), the second welded part (303), and the second connecting part (304) are t1, t2, t3, and t4, respectively; Wherein, t1, t2, t3, and t4 are all taken as 0.2mm to 0.4mm.

4. The cylindrical battery through-welding composite structure according to claim 1, characterized in that, The width of the first welded portion (301) of the connector (3) is w1, and w1 is 1.5mm ~ 3.5mm.

5. The cylindrical battery through-welding composite structure according to claim 1, characterized in that, The width of the second welded portion (303) of the connector (3) is w2, and w2 is 2.0mm ~ 5.0mm.

6. The cylindrical battery through-welding composite structure according to claim 1, characterized in that, After the second connecting part (304) of the connector (3) extends into the cavity (201), its lower end face extends beyond the lower surface of the collector plate (2) by at least 0.1 mm.

7. The cylindrical battery through-welding composite structure according to claim 1, characterized in that, The stepped portion (101) of the housing (1), the cavity (201) of the collecting plate (2), and the horizontal cross-section of the connector (3) are all circular.

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