Secondary battery, battery pack, and electronic device

Abstract

The invention provides a secondary battery, a battery pack and an electronic device. The secondary battery comprises a shell, an electrode assembly, an electrode terminal and an insulating sealing piece, the electrode assembly is accommodated in the shell; the electrode terminal is electrically connected with the electrode assembly, is exposed out of the shell and is in insulated connection with the shell; the insulating sealing element is positioned between the electrode terminal and the shell; the electrode terminal is provided with a first end face exposed out of the shell, the welding part is arranged on the first end face in a protruding mode in the vertical direction, and the welding part comprises at least one connecting side wall used for being connected with an external component in a seam welding mode. The technical problem that the functionality is reduced or even fails due to the fact that the insulating sealing piece near the electrode terminal is affected by welding heat of the connecting piece can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a secondary battery, a battery pack and an electronic device. Background Art

[0002] The current mainstream battery pack is composed of multiple secondary batteries welded together using connectors to form a continuous circuit. This connection method has the advantages of high efficiency, reliability and safety, and is therefore widely used in power systems.

[0003] Typically, a connector is welded to the positive and / or negative terminals of a secondary battery. Through-hole welding is typically used to weld the connector to the electrode terminal, first penetrating the connector and then fusing it to the electrode terminal. This welding method requires high laser welding energy, which can lead to excessive temperature rise in the welded portion of the electrode terminal and its surrounding areas. Temperature-sensitive components such as seals and insulators are often located near the electrode terminals. These components are sensitive to temperature and can be easily damaged, leading to functional failure, which in turn affects the quality or lifespan of the secondary battery and may even cause safety issues. Summary of the Invention

[0004] The present invention provides a secondary battery, a battery pack and an electronic device to improve the technical problem that the functionality of insulating seals near electrode terminals is reduced or even fails due to the influence of welding heat of connecting pieces.

[0005] To achieve the above-mentioned objectives and other related objectives, the present invention provides a secondary battery, a battery pack and an electronic device, wherein the secondary battery includes a shell, an electrode assembly, an electrode terminal and an insulating seal; the electrode assembly is accommodated in the shell; the electrode terminal is electrically connected to the electrode assembly and exposed to the shell, and is insulated from the shell; the insulating seal is located between the electrode terminal and the shell; the electrode terminal has a first end face exposed to the shell, and the secondary battery also includes a welding portion protruding from the first end face in a vertical direction, the welding portion including at least one connecting side wall for seam welding to an external component.

[0006] In an example of the secondary battery of the present invention, the connecting sidewall extends vertically along the vertical direction, and the connecting sidewall of the welding portion extends linearly in the projection plane in the vertical direction; the connecting sidewall extends straightly or in an arc line in the projection plane.

[0007] In an example of the secondary battery of the present invention, the minimum width of the electrode terminal in the horizontal direction perpendicular to the vertical direction is H1, and the minimum width of the welding portion in the horizontal direction is H2, where H2≤0.5H1.

[0008] In an example of a secondary battery of the present invention, the electrode terminal includes a terminal body and a sealing portion fixed at the center of the terminal body, the terminal body is electrically connected to the electrode assembly, the insulating sealing member is located between the shell and the terminal body, the sealing portion has a second end face exposed to the terminal body, and the welding portion is arranged at the center of the second end face.

[0009] In an example of a secondary battery of the present invention, a central hole is provided in the terminal body, a sealing portion is provided in the central hole, the sealing portion seals the central hole, the second end face is located on the side of the sealing portion away from the electrode assembly, and the sealing portion and the welding portion are integrally formed or separately fixedly connected.

[0010] In an example of a secondary battery of the present invention, the connecting side wall of the welding portion includes a first vertical side wall and a second vertical side wall respectively formed on two opposite sides of the welding portion, the first vertical side wall and the second vertical side wall extend vertically in the vertical direction and are axially symmetrically arranged, and extend linearly in the projection plane, the maximum horizontal distance between the first vertical side wall and the second vertical side wall along the vertical direction is L, the minimum width dimension of the electrode terminal in the horizontal direction is H1, L≤0.5H1, and the width of the first vertical side wall and / or the second vertical side wall along the horizontal direction fully covers the first end surface of the electrode terminal.

[0011] The present invention also provides a battery pack, which includes a plurality of secondary batteries and a plurality of connecting plates, wherein the plurality of secondary batteries are welded to the connecting plates; the secondary battery includes a shell, an electrode assembly, an electrode terminal and an insulating seal; the electrode assembly is accommodated in the shell; the electrode terminal is electrically connected to the electrode assembly and exposed to the shell, and is insulated from the shell; the insulating seal is located between the electrode terminal and the shell; the electrode terminal has a first end face exposed to the outside of the shell, and the secondary battery also includes a welding portion protruding from the first end face along a vertical direction, the welding portion includes at least one connecting side wall, the connecting plate is seam welded to the connecting side wall, and a welding trace area is formed.

[0012] In an example of the battery pack of the present invention, the height of the welding trace area along the vertical direction is less than or equal to the height E of the welding portion along the vertical direction. The height of the welding trace area along the vertical direction is H, and E / 3≤H≤E / 2.

[0013] In one example of the battery pack of the present invention, the connecting plate includes a first connecting portion and a second connecting portion; the connecting side wall includes a first vertical side wall and a second vertical side wall respectively formed on two opposite sides of the welding portion and arranged axially symmetrically, the first connecting portion is welded to the first vertical side wall, and the second connecting portion is welded to the second vertical side wall.

[0014] The present invention further provides an electronic device comprising any one of the above battery packs.

[0015] The secondary battery of the present invention features a protruding welding portion on the first end surface and a connecting sidewall for seam welding to external components. This significantly reduces welding energy and heat input during welding, effectively controlling the temperature rise of the electrode terminals and the surrounding area during welding. This reduces thermal damage to the insulating seal and mitigates issues such as reduced functionality or failure of the insulating seal. Furthermore, the connecting sidewall design of the weld ensures a secure seam weld connection to the external component, balancing process improvement with connection strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic structural diagram of an embodiment of a secondary battery of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of an electrode assembly of a secondary battery according to an embodiment of the present invention;

[0019] Figure 3 for Figure 1 A partial enlarged view of point A in the middle;

[0020] Figure 4 A top view of an embodiment of a secondary battery of the present invention;

[0021] Figure 5 A schematic structural diagram of an end wall, an electrode terminal, and a welding portion of a secondary battery according to an embodiment of the present invention;

[0022] Figure 6 A top view of an embodiment of a secondary battery of the present invention;

[0023] Figure 7 This is a schematic structural diagram of a secondary battery after welding connecting pieces in one embodiment of the present invention;

[0024] Figure 8 for Figure 5 Schematic diagram of the structure after welding the connecting piece;

[0025] Figure 9 A top view of a secondary battery according to an embodiment of the present invention after welding connecting pieces;

[0026] Figure 10 for Figure 9 BB cross-sectional view;

[0027] Figure 11 for Figure 10 A partial enlarged view of point C in the middle;

[0028] Figure 12 for Figure 11 A partial enlarged view of point D in the middle;

[0029] Figure 13 A top view of a secondary battery according to an embodiment of the present invention after welding connecting pieces;

[0030] Figure 14 A schematic diagram of a battery pack in an embodiment of an electronic device of the present invention;

[0031] Figure 15 FIG. 1 is a schematic diagram of an electronic device according to an embodiment of the present invention.

[0032] Component number description:

[0033] 1. Electronic device; 10. Battery pack; 11. Working unit; 101. Box; 102. Box cover; 100. Secondary battery; 110. Housing; 111. End wall; 1111. Electrode terminal mounting hole; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. First electrode piece; 1211. Positive electrode current collector; 1212. First coated area; 1213. First uncoated area; 122. Separator; 123. Second electrode piece; 1231. Negative electrode current collector; 1232. Second coated area; 1233. Second uncoated area; 124. First tab; 125. Second tab; 130. Cover plate; 140. Electrode terminal; 141, first end face; 142, terminal body; 143, columnar portion; 144, inner flange; 145, outer flange; 146, center hole; 150, sealing portion; 151, second end face; 160, welding portion; 161, connecting side wall; 1611, first vertical side wall; 1612, second vertical side wall; 162, welding trace area; 170, sealing member; 180, insulating member; 181, first insulating portion; 182, second insulating portion; 1821, first part; 1822, second part; 190, current collecting member; 200, connecting piece; 210, first connecting portion; 220, second connecting portion. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless they conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0035] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those in the examples of the present invention may also be used to implement the present invention.

[0036] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0037] See also Figures 1 to 15 The present invention provides a secondary battery 100, a battery pack 10, and an electronic device 1. The electrode terminal 140 in the secondary battery 100 has a first end surface 141 exposed to the housing 110. By vertically protruding a welding portion 160 on the first end surface 141 and welding the welding portion 160 to an external component by seam welding, the energy required for welding can be significantly reduced, the heat input during the welding process can be reduced, and the temperature rise of the electrode terminal 140 and the surrounding area during the welding process can be effectively controlled, thereby reducing thermal damage to the insulating seal and alleviating the problem of reduced functionality or functional failure of the insulating seal, thereby improving the battery quality, service life, and safety of the secondary battery 100.

[0038] See also Figure 1 The secondary battery 100 includes a housing 110 , an electrode assembly 120 , an electrode terminal 140 , an insulating seal, and a cap plate 130 .

[0039] See also Figure 1The shell 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection relationship can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in a variety of ways, such as integral stamping, integral casting, or split welding. The surrounding of the side wall 112 is not limited, and can be cylindrical or prismatic, or can be surrounded along any other closed loop contour that can match the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical and surrounds the outer edge of the end wall 111, and a circular opening 113 is formed at the end of the side wall 112 away from the end wall 111. A accommodating cavity is formed in the shell 110 surrounded by the end wall 111 and the side wall 112, which is used to accommodate the electrode assembly 120, electrolyte and other necessary battery components.

[0040] See also Figure 1 and Figure 2 The electrode assembly 120 is housed in the housing 110. The electrode assembly 120 is a component where electrochemical reactions occur in the secondary battery 100. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 includes an electrode structure formed by stacking or winding a first electrode sheet 121, a second electrode sheet 123, and a separator 122. The polarity of the first electrode sheet 121 and the second electrode sheet 123 are opposite. In some embodiments, the first electrode sheet 121 is a positive electrode sheet and the second electrode sheet 123 is a negative electrode sheet. In other embodiments, the first electrode sheet 121 is a negative electrode sheet and the second electrode sheet 123 is a positive electrode sheet.

[0041] See also Figures 1 to 2 In this embodiment, the first electrode sheet 121 is a positive electrode sheet, and the first electrode sheet 121 includes a positive electrode current collector 1211 and a positive electrode active material. The positive electrode active material is coated on the surface of the positive electrode current collector 1211; the positive electrode current collector 1211 includes a first coated area 1212 coated with the active material and a first uncoated area 1213 not coated with the active material. The first uncoated area 1213 is located at the end of the first electrode sheet 121. The first uncoated area 1213 extends out of the separator 122 along the winding axis direction of the electrode assembly 120 and is bent toward the winding axis to form a first electrode tab 124. The first electrode tab 124 is the corresponding positive electrode tab.

[0042] See also Figures 1 to 2The second electrode sheet 123 is a negative electrode sheet. Specifically, the second electrode sheet 123 includes a negative electrode current collector 1231 and a negative electrode active material. The negative electrode active material is coated on the surface of the negative electrode current collector 1231; the negative electrode current collector 1231 includes a second coated area 1232 coated with an active material and a second uncoated area 1233 not coated with an active material. The second uncoated area 1233 is located at the end of the second electrode sheet 123. The other end of the second uncoated area 1233 extends out of the diaphragm 122 along the winding axis direction of the electrode assembly 120 and is bent toward the winding axis to form a second electrode tab 125. The second electrode tab 125 is the corresponding negative electrode tab.

[0043] See also Figures 1 to 2 The separator 122 is disposed between the first electrode sheet 121 and the second electrode sheet 123 to separate the positive electrode active material layer from the negative electrode active material layer. Taking the lithium-ion secondary battery 100 as an example, the positive electrode current collector 1231 can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode current collector 1211 can be made of copper, and the negative electrode active material can be carbon or silicon. The base material of the separator 122 can be polypropylene (PP) or polyethylene (PE).

[0044] See also Figure 1 and Figure 2 Furthermore, first tab 124 faces end wall 111 or opening 113, while second tab 125 faces the other end of housing 110. In this embodiment, first tab 124 faces end wall 111 and is electrically connected to electrode terminal 140, causing electrode terminal 140 to be positively charged. Second tab 125 faces opening 113, and housing 110 is electrically connected to second tab 125, causing housing 110 to be negatively charged. However, in other embodiments, second tab 125 may be connected to electrode terminal 140, while first tab 124 may be connected to housing 110.

[0045] See also Figure 1 The cover plate 130 is sealed and installed on the opening 113; the outer edge shape of the cover plate 130 corresponds to the shape of the opening 113, and is connected to the side wall 112 to seal the opening 113. The installation method of the cover plate 130 includes but is not limited to mechanical sealing or welding sealing. In this embodiment, the cover plate 130 is sealed and blocked on the opening 113 by mechanical sealing.

[0046] See also Figure 1 and Figure 3In this embodiment, the electrode terminal 140 passes through the end wall 111 and is insulated from the end wall 111. The structure of the electrode terminal 140 can be any suitable form that can pass through the end wall 111 and electrically connect to the first electrode tab 124 of the electrode assembly 120. For example, the cross-section can be circular, square, prismatic, or a special-shaped profile that can achieve stable electrical conductivity. The electrode terminal 140 is electrically connected to the electrode assembly 120. The end of the electrode terminal 140 facing the electrode assembly 120 passes through the end wall 111 and is directly electrically connected to the first electrode tab 124 or through an indirect transfer connection. In this embodiment, the electrode terminal 140 is electrically connected to the first electrode tab 124 through a current collecting member 190. The end of the electrode terminal 140 facing the opening 113 is welded to the current collecting member 190, and the side of the current collecting member 190 facing away from the electrode terminal 140 is welded to the first electrode tab 124. One end of the electrode terminal 140, facing away from the electrode assembly 120, is exposed to the exterior of the housing 110 to form a corresponding electrode. The electrical conductivity of the electrode terminal 140 can be positive or negative. For example, in one embodiment, if the polarity of the first electrode tab 124 is a negative electrode tab, the electrode terminal 140 is the negative electrode, and the housing 110 forms the corresponding positive electrode. In this embodiment, if the polarity of the first electrode tab 124 is a positive electrode tab, the electrode terminal 140 is the positive electrode, and the housing 110 forms the corresponding negative electrode.

[0047] See also Figure 3 The end wall 111 is provided with an electrode terminal mounting hole 1111, and the electrode terminal 140 is sealed and insulatedly mounted within the electrode terminal mounting hole 1111. The electrode terminal 140 is connected to the housing 110 via an insulating seal. The insulating seal can be implemented in various ways to achieve a sealed and electrically insulated connection between the electrode terminal 140 and the end wall 111 of the housing 110. For example, the insulating seal can be implemented by placing an insulating member 180 between the electrode terminal 140 and the end wall 111 to achieve insulation, and by providing a seal 170 to achieve sealing. The insulating member 180 and the seal 170 can be integrated or assembled separately. Alternatively, insulation can be achieved by forming an insulating coating layer on a portion of the electrode terminal 140. Alternatively, some of the above methods can be combined. Alternatively, the function of the insulating seal is not limited to achieving insulation and sealing the connection between the end wall 111 and the electrode terminal 140. It can also have other functions, such as strengthening the connection to the electrode terminal 140 or preventing deformation.

[0048] See also Figure 3The electrode terminal 140 includes a columnar portion 143, an inner flange 144 and an outer flange 145. The columnar portion 143 passes through the electrode terminal mounting hole 1111. The cross-section of the columnar portion 143 can be circular, square, prismatic or other special-shaped contours that can achieve stable conductivity. Considering the better sealing and matching effects, preferably, the columnar portion 143 is adapted to the electrode terminal mounting hole 1111, that is, the electrode terminal mounting hole 1111 corresponds to the shape of the columnar portion 143. In this embodiment, the cross-section of the columnar portion 143 is circular, and the circular design facilitates processing, assembly and sealing.

[0049] See also Figure 3 The inner flange 144 is located inside the shell 110 and extends from the columnar portion 143 to the periphery of the end wall 111. Specifically, the inner flange 144 connects the end of the columnar portion 143 located inside the shell 110 and extends along the side of the end wall 111 facing the inside of the shell 110 toward the outer edge of the end wall 111; the outer cross-section of the inner flange 144 can be circular, square, prismatic or other special-shaped contours that can achieve stable conductivity, and there is no limitation on this; the outer flange 145 connects the end of the columnar portion 143 located outside the shell 110 and extends along the side of the end wall 111 facing the outside of the shell 110 toward the outer edge of the end wall 111; the outer cross-section of the outer flange 145 can be circular, square, prismatic or other special-shaped contours that can achieve stable conductivity, and there is no limitation on this.

[0050] See also Figure 3 The seal 170 is located between the electrode terminal 140 and the housing 110. The installation position of the seal 170 is not limited. For example, it can be set between the columnar portion 143 and the electrode terminal mounting hole 1111, between the outer flange 145 and the outer side of the end wall 111, or between the inner flange 144 and the inner side of the end wall 111. In some embodiments, the seal 170 can be set at multiple locations in the above positions to achieve electrolyte sealing and gas sealing. In this embodiment, the seal 170 is arranged around the columnar portion 143 and is clamped between the outer flange 145 and the end wall 111. This arrangement can provide axial compression force to the seal 170 by pressing the outer flange 145 and the end wall 111, so that the seal 170 deforms evenly, fills all microscopic gaps, and improves sealing performance. The seal 170 is made of an elastic material. The material of the seal 170 can be EPDM rubber, fluorosilicone rubber, or fluororubber, but is not limited to this.

[0051] See also Figure 3The insulating member 180 can have various structural forms, which are not limited to these, as long as it can isolate the electrode terminal 140 from the housing 110. In this embodiment, the insulating member 180 includes a first insulating portion 181 and a second insulating portion 182, both of which are disposed around the columnar portion 143. The first insulating portion 181 is clamped between the outer flange 145 and the end wall 111 on the side facing away from the electrode assembly 120 to provide electrical insulation between the outer flange 145 and the end wall 111. The second insulating portion 182 includes a first portion 1821 disposed between the columnar portion 143 and the electrode terminal mounting hole 1111, and a second portion 1822 clamped between the inner flange 144 and the end wall 111. The first portion 1821 and the second portion 1822 can be integrally formed or separately disposed. The second insulating portion 182 is used to provide electrical insulation between the columnar portion 143 and the electrode terminal mounting hole 1111, and between the inner flange 144 and the end wall 111. Preferably, the seal 170 is arranged on the inner side of the first insulating part 181, and the first insulating part 181 and the second insulating part 182 serve as rigid supports to maintain a fixed distance between the electrode terminal 140 and the shell 110. The seal 170 can absorb mechanical vibration or thermal expansion and contraction stress. Since the seal 170 is adjacent to both the first insulating part 181 and the second insulating part 182, the deformation of the insulating part 180 due to mechanical vibration or thermal expansion and contraction stress can be alleviated, thereby improving the structural performance of the secondary battery 100 and increasing its service life.

[0052] Considering that the multiple secondary batteries 100 in the battery pack 10 need to be connected in series or in parallel by welding the connecting piece 200, in some embodiments, the connecting piece 200 and the electrode terminal 140 are generally welded by penetration welding, which requires first welding through the connecting piece 200 and then fusing it with the electrode terminal 140. This welding method requires a large amount of laser welding energy, which will cause the temperature of the electrode terminal 140 near the weld to rise too high, thereby causing the temperature of the area near the electrode terminal 140 to rise. Since the insulating seal is more sensitive to high temperatures, it is easy to cause its insulation and sealing performance to deteriorate or even fail to function. In this embodiment, please refer to Figures 3 to 7 The surface where the connecting piece 200 is welded to the electrode terminal 140 is the first end surface 141 of the electrode terminal 140 exposed to the housing 110. In this embodiment, the end surface of the outer flange 145 facing away from the housing 110 is the first end surface 141. A welding portion 160 is provided on the first end surface 141 along a vertical direction. Figure 3 and Figure 12As shown in the X-direction, the welding portion 160 includes at least one connecting sidewall 161 for seam welding to the connecting piece 200. The shape of the welding portion 160 is not limited, as long as it protrudes from the first end surface 141 and forms a connecting sidewall 161 for seam welding. The shape of the connecting sidewall 161 is not limited and can, for example, be a flat surface, a curved surface (arc surface, circumferential surface, wavy surface, etc.), a bent surface, a combination of two or more of the above shapes, or any other shape capable of forming a seam weld with the connecting piece 200.

[0053] In this technical solution, by providing a vertically protruding welding portion 160 on the first end surface 141, the welding method between the electrode terminal 140 and the external component is improved from penetration welding to seam welding. This significantly reduces the welding energy required, reduces the heat input during the welding process, and effectively controls the welding temperature rise, thereby reducing thermal damage to the insulating seal between the electrode terminal 140 and the housing 110, alleviating performance degradation or functional failure. In addition, the connecting side wall 161 designed for the welding portion 160 ensures the stability of the seam weld connection with the external component, balancing process improvement and connection strength.

[0054] See also Figures 3 to 6 In one embodiment of the secondary battery 100 of the present invention, the connecting sidewall 161 extends vertically in the vertical direction, and the connecting sidewall 161 of the welding portion 160 extends linearly in the vertical projection plane. The shape of the connecting sidewall 161 determines the direction and shape of the weld trace region 162 formed by welding the connecting piece 200 to the electrode terminal 140. The linear extension path of the connecting sidewall 161 in the projection plane is not limited, and may include, for example, a straight line, a curved line, a broken line, or other irregular linear extension paths. The connecting sidewall 161 may form corresponding shapes corresponding to different extension paths. In one embodiment, the welding portion 160 includes only one connecting sidewall 161, such as a cylindrical or solid structure enclosed by a closed curved surface. In another embodiment, the welding portion 160 includes multiple connecting sidewalls 161. The linear extension paths of these multiple connecting sidewalls 161 may be the same, such as a rectangular parallelepiped structure, a polygonal structure, a Y-shaped structure, a circular ring structure, etc., or different, such as a U-shaped structure. This is not limited to any of these. The connecting side walls 161 of the above-mentioned shapes can realize seam welding between the connecting piece 200 and the welding portion 160, which can reduce the heat input during the welding process, effectively control the welding temperature rise range, and achieve the effect of reducing thermal damage to the insulating seal.

[0055] See also Figures 4 and 5In one embodiment of the secondary battery 100 of the present invention, the connecting side wall 161 extends linearly in the projection plane, and the welding portion 160 is formed with at least one planar connecting side wall 161 for seam welding with the connecting piece 200. The linearly extending connecting side wall 161 shortens the length of the weld trace, which can limit the heat input during the welding process and further control the welding temperature rise, thereby reducing thermal damage to the insulating seal between the electrode terminal 140 and the housing 110. In addition, the shortened length of the weld trace area 162 can also improve welding efficiency. In one embodiment, please refer to Figure 4 Welding portion 160 includes two opposing, parallel, first and second vertical sidewalls 1611, 1612. Both first and second vertical sidewalls 1611, 1612 extend linearly along the projection plane. Both first and second vertical sidewalls 1611, 1612 are seam-welded to connecting piece 200, ensuring both efficient and secure welding.

[0056] See also Figure 6 In one embodiment of the secondary battery 100 of the present invention, the connecting side wall 161 extends in an arc shape on the projection plane, and the welding portion 160 is formed with at least one connecting side wall 161 with an arc surface, which is used for seam welding with the connecting piece 200. The number of connecting side walls 161 included in the welding portion 160 is not limited, and can be one, such as a cylindrical welding portion 160, or multiple, such as a welding portion 160 with a circular ring structure, a fan-shaped structure, or a U-shaped structure. In one embodiment, please refer to Figure 6 The welding portion 160 is cylindrical and includes only one connecting side wall 161. The connecting side wall 161 of this shape can be adapted to the connecting piece 200 with a circular arc inner wall for seam welding. The circular arc connecting side wall 161 can strengthen the radial fixing effect of the connecting portion, thereby improving the welding firmness.

[0057] See also Figure 6 In one embodiment of the secondary battery 100 of the present invention, the minimum width of the electrode terminal 140 along the horizontal direction perpendicular to the vertical direction is H1, and the minimum diameter of the weld portion 160 along the horizontal direction is H2, where H2 ≤ 0.5H1. By limiting the diameter of the weld portion 160, the weld portion 160 has a smaller weld area. This configuration can reduce the thermal impact of welding on the insulating seal, concentrate the heat source, and prevent lateral heat diffusion, thereby reducing thermal damage to the insulating seal caused by welding and alleviating the problem of reduced functionality or functional failure of the insulating seal.

[0058] See also Figure 3In one embodiment of the secondary battery 100 of the present invention, the electrode terminal 140 includes a terminal body 142. The shape of the terminal body 142 is not limited, as long as the terminal body 142 can be electrically connected to the electrode assembly 120 and exposed to the housing 110. The insulating seal is located between the housing 110 and the terminal body 142. The insulating seal includes a seal 170 and an insulating member 180. The insulating member 180 and the seal 170 can be provided in an integrated manner or in a separate assembly manner. The structural form of the seal 170 and the insulating member 180 is not limited, and the installation position between the housing 110 and the terminal body 142 is also not limited. As long as the seal 170 can achieve electrolyte and gas sealing for the secondary battery 100, and the insulating member 180 can achieve insulation between the housing 110 and the electrode terminal 140, it is sufficient. The electrode terminal 140 includes a sealing portion 150 fixed to the center of the terminal body 142. The shape of the sealing portion 150 is not limited and may be a cylindrical, truncated cone, polygonal prism or polygonal pyramid structure. The sealing portion 150 has a second end face 151 exposed to the terminal body 142, and the welding portion 160 is arranged at the center of the second end face 151. First, the terminal body 142 is responsible for electrically connecting the electrode assembly 120, and the sealing portion 150 independently assumes the welding function, thereby achieving physical separation of the electrical connection and the welding heat source, and reducing the conduction of welding heat to the insulating seal. Secondly, the welding portion 160 is located at the center of the second end face 151, which can make the welding heat distribution more uniform to prevent local overheating from causing reduced functionality or functional failure of the insulating seal. Thirdly, the welding portion 160 can be kept at a sufficient distance from the insulating seal to reduce the direct conduction of welding heat to the insulating seal.

[0059] Generally, the electrode terminal 140 is electrically connected to the electrode assembly 120 by welding to the current collecting member 190. Torque welding or penetration welding is usually used to weld the current collecting member 190 to the terminal body 142. Torque welding requires welding inside the battery, which limits the welding space and makes welding inconvenient. Penetration welding is performed outside the battery case 110. Due to the large thickness of the terminal body 142, it is difficult to control the welding energy, resulting in poor welding results. Figures 3 to 6In one embodiment of the secondary battery 100 of the present invention, the terminal body 142 is provided with a central hole 146. The provision of central hole 146 not only reduces the thickness of the welded connection between the terminal body 142 and the current collecting member 190, but also facilitates the welding connection between the terminal body 142 and the current collecting member 190 within the central hole 146. A sealing portion 150 is disposed within the central hole 146, exposing a second end surface 151 relative to the central hole 146. The sealing portion 150 seals the central hole 146, with the second end surface 151 located on the side of the sealing portion 150 facing away from the electrode assembly 120. While sealing the central hole 146, the sealing portion 150 also serves as a weld to the connecting piece 200, physically separating the electrical connection from the welding heat source and reducing the conduction of welding heat to the insulating seal.

[0060] See also Figures 3 to 6 In one embodiment of the secondary battery 100 of the present invention, the sealing portion 150 and the welding portion 160 are integrally formed or separately fixedly connected, and this is not limited. The structure in which the sealing portion 150 and the welding portion 160 are integrally formed has high structural strength, which can reduce the risk of loosening or breaking between the sealing portion 150 and the welding portion 160, and the process is simplified and suitable for mass production. The form in which the sealing portion 150 and the welding portion 160 are separately fixedly connected can achieve the use of different materials for the sealing portion 150 and the welding portion 160, so that the sealing portion 150 has better corrosion resistance and sealing, while the welding portion 160 has better welding performance.

[0061] See also Figures 3 to 5 In one embodiment of the secondary battery 100 of the present invention, the connecting sidewall 161 of the weld portion 160 includes a first vertical sidewall 1611 and a second vertical sidewall 1612 formed on opposite sides of the weld portion 160. The first vertical sidewall 1611 and the second vertical sidewall 1612 extend perpendicularly in the vertical direction and are arranged axially symmetrically. They also extend linearly in the projection plane. In this embodiment, the first vertical sidewall 1611 and the second vertical sidewall 1612 are configured as vertical sidewalls and are arranged parallel to each other. The maximum horizontal distance between the first vertical sidewall 1611 and the second vertical sidewall 1612 is L, and the minimum horizontal width of the electrode terminal 140 is H1, where L≤0.5H1. This dimension restriction can reduce the welding area of ​​the weld portion 160, thereby reducing heat input and effectively controlling the welding temperature rise, thereby reducing thermal damage to the insulating seal and alleviating the problem of reduced functionality or functional failure of the insulating seal. In addition, it can provide sufficient space for the connecting piece 200.

[0062] See also Figures 3 to 5In one embodiment of the secondary battery 100 of the present invention, the horizontal width of the first vertical sidewall 1611 and / or the second vertical sidewall 1612 fully covers the first end surface 141 of the electrode terminal 140. While satisfying L≤0.5H1 to reduce heat input, the weld portion 160 maximizes the connection area along its length to provide stable mechanical support, allowing the welding stress to be transmitted along the first end surface 141, thereby reducing the risk of fatigue failure at the connection between the connecting piece 200 and the weld portion 160. It should be noted that the position of the weld portion 160 is not limited. In some embodiments, the center of the weld portion 160 coincides with the center of the first end surface 141, or at least the weld portion 160 passes through the center of the first end surface 141 to improve the balance of heat conduction. In this embodiment, the weld portion 160 is offset relative to the center of the first end surface 141 to match the size and shape of the connecting piece 200.

[0063] See also Figures 7 to 14 The present invention also provides a battery pack 10, which includes a plurality of secondary batteries 100 and a plurality of connecting pieces 200. The plurality of secondary batteries 100 are welded to the connecting pieces 200. In one embodiment of the battery pack 10 of the present invention, the battery pack 10 also includes a housing 101, a housing cover 102, and a plurality of secondary batteries 100. The plurality of secondary batteries 100 are placed in the housing 101 and are connected in series or in parallel, or in a mixture of series and parallel connections. The housing cover 102 is sealed on the housing 101 to protect the plurality of secondary batteries 100. It should be noted that, in addition to the secondary batteries 100 of the present invention, the battery pack 10 may also include a battery pack 10 thermal management system, a circuit board, and other components. The battery pack 10 may be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0064] See also Figures 10 and 11 In one embodiment of the battery pack 10 of the present invention, the secondary battery 100 includes a housing 110, an electrode assembly 120, an electrode terminal 140, and an insulating seal. The electrode assembly 120 is housed within the housing 110. The electrode terminal 140 is electrically connected to the electrode assembly 120 and exposed to the housing 110, and is insulated from the housing 110. The insulating seal is located between the electrode terminal 140 and the housing 110. The electrode terminal 140 has a first end surface 141 exposed to the outside of the housing 110. The secondary battery 100 also includes a welding portion 160 protruding from the first end surface 141 in a vertical direction. The welding portion 160 includes at least one connecting side wall 161. The specific structure of the above-mentioned technical features of the secondary battery 100 is described in detail in the above-mentioned embodiment of the secondary battery 100 and is not repeated here.

[0065] See also Figure 9 、 Figure 12 and Figure 13Furthermore, the connecting piece 200 is seam-welded to the connecting side wall 161, forming a weld track area 162. The horizontal length and shape of the weld track area 162 are not limited. For example, the joint surface of the connecting piece 200 and the connecting side wall 161 is formed into a continuous weld track area 162 or a discontinuous weld track area 162 by seam welding. The weld track area 162 fully or partially covers the joint surface of the connecting piece 200 and the connecting side wall 161 in the horizontal direction. The shape of the weld track area 162 is not limited. The shape of the weld track area 162 depends on the welding method used. There are many welding methods for seam welding, which are not limited to this. For example, when laser welding is used, the surface has continuous or discontinuous fish-scale patterns. When resistance welding is used, the surface has two parallel indentations. When ultrasonic welding is used, the surface has a frosted texture caused by friction. When micro-beam plasma welding is used, the weld is a narrow and deep straight line with a smooth surface and a slight concave. Compared with penetration welding, the above welding forms can all achieve seam welding, reduce heat input during the welding process, effectively control the welding temperature rise, and thereby reduce thermal damage to the insulating seal between the electrode terminal 140 and the shell 110, and alleviate the problem of reduced functionality or functional failure of the insulating seal.

[0066] See also Figure 12 In one embodiment of the battery pack 10 of the present invention, the vertical height of the weld trace region 162 is less than or equal to the vertical height of the weld portion 160. Limiting the height of the weld trace region 162 to no greater than the vertical height of the weld portion 160 can prevent melting of the terminal body 142, thereby preventing increased thermal impact on the insulating seal and thereby alleviating reduced functionality or failure of the insulating seal.

[0067] See also Figure 12 In one embodiment of the battery pack 10 of the present invention, the vertical height of the weld portion 160 is E, and the height of the weld trace area 162 is H, where E / 3 ≤ H ≤ E / 2. Specifying H ≥ E / 3 ensures that the height of the weld trace area 162 is sufficient to form a continuous metallurgical bond, avoiding cold welds or insufficient strength caused by an excessively small weld trace area 162, and improving the mechanical bearing capacity of the connecting piece 200 and the electrode terminal 140. Specifying H ≤ E / 2 prevents excessive welding heat from being too high, resulting in excessive proximity to the insulating seal, and reduces the temperature rise of the weld, thereby alleviating thermal damage to the insulating seal and mitigating the problem of reduced functionality or failure of the insulating seal.

[0068] See also Figure 9 and Figure 13In one embodiment of the battery pack 10 of the present invention, the shape of the projection of the welding trace area 162 in the vertical direction is linear, specifically a straight line and / or an arc. For example, the shape of the projection of the welding trace area 162 can be a straight line, an arc, or a combination of a straight line and an arc. The shape of the welding trace area 162 depends on the shape of the connecting side wall 161 connected to the connecting piece 200. For example, after welding the connecting side wall 161 extending in a straight line, a straight welding trace area 162 is formed. This setting makes it easier to control energy, so as to control the welding temperature rise amplitude and improve welding efficiency. After welding the connecting side wall 161 extending in an arc, an arc-shaped welding trace area 162 is formed. The welding portion 160 of this shape is adapted to the connecting piece 200 with an inner wall having a circular arc surface. This matching form has its own limiting function, has a high fixing effect, and improves the welding firmness.

[0069] See also Figures 11 to 12 In one embodiment of the battery pack 10 of the present invention, the connecting piece 200 includes a first connecting portion 210 and a second connecting portion 220. The connecting sidewall 161 includes a first vertical sidewall 1611 and a second vertical sidewall 1612, formed on opposite sides of the welding portion 160 and arranged axially symmetrically. In this embodiment, the two are configured as vertical sidewalls and arranged parallel to each other. The first connecting portion 210 is welded to the first vertical sidewall 1611, and the second connecting portion 220 is welded to the second vertical sidewall 1612. In this embodiment, the connecting piece 200 is welded to the welding portion 160 to form two weld trace areas 162. This ensures that the thermal impact of the welding on the insulating seal is reduced while ensuring the weld is secure. Furthermore, this configuration of the connecting piece 200 more evenly affects the thermal impact on the insulating seal during welding, avoiding premature failure due to excessive localized thermal impact. The first connecting portion 210 and the second connecting portion 220 can be components that perform the same electrical function or different electrical functions, which is not specifically limited in this application. In other embodiments, the connecting piece 200 may be provided with more connecting parts based on the requirements of electrical functions, and each connecting part is welded to the corresponding vertical side wall, and the welding method is seam welding.

[0070] See also Figure 9 and Figure 13 In one embodiment of the battery pack 10 of the present invention, the connecting piece 200 is connected to the connecting side wall 161 by laser welding. Laser welding requires low energy and can precisely control the heat input. This can not only reduce the heat input during the welding process, but also effectively control the temperature rise of the electrode terminal 140 and its surrounding area during the welding process, thereby reducing thermal damage to the insulating seal and alleviating the problem of reduced functionality or functional failure of the insulating seal. However, considering different processing and usage scenarios, other welding methods may also be used in some other embodiments, which are not limited to this, such as resistance welding, ultrasonic welding, or micro-beam plasma welding.

[0071] See also Figure 9 and Figure 13 In one embodiment of the battery pack 10 of the present invention, the laser beam used to form each weld track region 162 is a continuous wave laser beam. This allows for a single weld, eliminating repeated positioning and start-stop time, and improving process efficiency. Continuous wave lasers also enable centralized energy regulation, providing stable energy output, avoiding the intermittent energy fluctuations associated with pulsed welding, and reducing the risk of heating the insulating seal.

[0072] In an embodiment of the battery pack 10 of the present invention, laser welding adopts one or more welding methods of single-wire welding and multi-wire welding. Single-wire welding can quickly complete straight / curved welds, which can save energy and reduce consumption. Multi-wire welding refers to the use of multiple welding wires or multiple welding heads to weld the same workpiece or multiple welding points at the same time during the welding process. This technology can adopt multi-wire welding, multi-head welding or multi-layer multi-pass welding according to different welding requirements. Through parallel or staggered welding line design, welding efficiency is improved, and heat input diversion is achieved, reducing single-point heat accumulation. Through the configurability of welding strategies, this solution can achieve a dynamic optimal balance between efficiency, quality and thermal management.

[0073] See also Figure 15 The present invention also provides an electronic device 1, which includes the above-mentioned battery pack 10. The working part 11 is electrically connected to the battery pack 10 to obtain power support. As an example, the electronic device 1 is a vehicle, and the vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc., but is not limited to this. The working part 11 is the vehicle body, and the battery pack 10 is arranged at the bottom of the vehicle body and provides power support for the driving of the vehicle or the operation of the electrical components in the vehicle. However, in some other embodiments, the electronic device 1 can also be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy and an electric tool, etc. Spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.; the working part 11 can be a unit component that can obtain power from the battery pack 10 and perform corresponding work, such as a fan blade rotation unit, a vacuum cleaner's dust collection unit, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys; electric tools include metal cutting tools, grinding tools, assembly tools, and railway tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The present embodiment does not impose any particular restrictions on the electronic device 1.

[0074] The secondary battery of the present invention utilizes a vertically protruding weld portion on the first end surface, improving the penetration welding process to a seam welding method. This significantly reduces the welding energy required, reduces the heat input during welding, and effectively controls the temperature rise of the electrode terminal and the surrounding area during welding, thereby reducing thermal damage to the insulating seal and alleviating the problem of reduced or even ineffective functionality of the insulating seal. Furthermore, the design of the connecting sidewall of the weld portion ensures the stability of the seam weld connection with the external component, balancing process improvement with connection strength.

[0075] Therefore, the present invention effectively overcomes some practical problems in the prior art and thus has high utilization value and practical significance. The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A secondary battery, characterized in that: include: case; an electrode assembly, housed in the housing; an electrode terminal electrically connected to the electrode assembly and exposed to the housing, and insulated from the housing; an insulating seal located between the electrode terminal and the housing; The electrode terminal has a first end surface exposed to the shell, and the secondary battery further includes a welding portion protruding from the first end surface along a vertical direction, and the welding portion includes at least one connecting side wall for seam welding connection with an external component.

2. The secondary battery according to claim 1, wherein The connecting side wall extends vertically along the vertical direction, and the connecting side wall of the welding portion extends linearly in the projection plane of the vertical direction; the connecting side wall extends in a straight line or in a circular arc in the projection plane.

3. The secondary battery according to claim 2, wherein The minimum width of the electrode terminal along a horizontal direction perpendicular to the vertical direction is H1, and the minimum width of the welding portion along the horizontal direction is H2, wherein H2≤0.5H1.

4. The secondary battery according to claim 1, wherein The electrode terminal includes a terminal body and a sealing portion fixed at the center of the terminal body, the terminal body is electrically connected to the electrode assembly, the insulating seal is located between the shell and the terminal body, the sealing portion has a second end face exposed to the terminal body, and the welding portion is arranged at the center of the second end face.

5. The secondary battery according to claim 4, wherein The terminal body is provided with a center hole, the sealing part is provided in the center hole, the sealing part seals the center hole, the second end face is located on the side of the sealing part away from the electrode assembly, and the sealing part and the welding part are integrally formed or separately fixedly connected.

6. The secondary battery according to claim 2, wherein: The connecting side wall of the welding portion includes a first vertical side wall and a second vertical side wall respectively formed on two opposite sides of the welding portion, the first vertical side wall and the second vertical side wall extend vertically in the vertical direction and are axially symmetrically arranged, and extend linearly in the projection plane, the maximum distance between the first vertical side wall and the second vertical side wall in the horizontal direction perpendicular to the vertical direction is L, the minimum width dimension of the electrode terminal in the horizontal direction is H1, wherein L≤0.5H1, and the width of the first vertical side wall and / or the second vertical side wall along the horizontal direction fully covers the first end surface of the electrode terminal.

7. A battery pack, characterized in that: It comprises a plurality of secondary batteries and a plurality of connecting pieces, wherein the plurality of secondary batteries are connected to the connecting pieces by welding; The secondary battery includes: case; an electrode assembly, housed in the housing; an electrode terminal electrically connected to the electrode assembly and exposed to the housing, and insulated from the housing; an insulating seal located between the electrode terminal and the housing; The electrode terminal has a first end surface exposed to the outside of the shell, and the secondary battery also includes a welding portion protruding from the first end surface in a vertical direction. The welding portion includes at least one connecting side wall, and the connecting piece is seam-welded to the connecting side wall to form a welding trace area.

8. The battery pack according to claim 7, wherein: Along the vertical direction, the height of the welding trace area is less than or equal to the height E of the welding portion along the vertical direction. Along the vertical direction, the height of the welding trace area is H, wherein E / 3≤H≤E / 2.

9. The battery pack according to claim 7, wherein: The connecting piece includes a first connecting portion and a second connecting portion; the connecting side wall includes a first vertical side wall and a second vertical side wall respectively formed on two opposite sides of the welding portion and arranged axially symmetrically, the first connecting portion is welded to the first vertical side wall, and the second connecting portion is welded to the second vertical side wall.

10. An electronic device, characterized in that: A battery pack comprising the battery according to any one of claims 7 to 9.

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