Secondary battery and electronic device

Abstract

The utility model provides a secondary battery and an electronic device. The secondary battery comprises a shell, an electrode assembly, an end cover and a current collecting component, the shell comprises a surrounding side wall, and an opening is formed in one end of the side wall; the electrode assembly is accommodated in the shell; the end cover covers and seals the opening, a weak part is arranged on the end cover, and the weak part is configured to be broken when the pressure in the shell exceeds a threshold value; the current collecting component is located between the end cover and the electrode assembly, and the end cover and the electrode assembly are electrically connected through the current collecting component; the current collecting component is provided with a plurality of convex parts protruding towards the end cover, the plurality of convex parts are provided with recesses on one side facing the electrode assembly, and each convex part is provided with a through hole, so that the technical problem that a chamber is easy to burst when the battery is subjected to thermal runaway can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery technical field, concretely relates to a secondary battery and electronic device. BACKGROUND

[0002] The big cylinder battery is more and more favored by major car enterprises due to its high safety, long life, excellent fast charging performance, excellent battery consistency and low production cost.

[0003] Generally, the cylindrical battery includes a housing, an electrode assembly disposed within the housing, and a current collecting member disposed between an end wall of the housing and a corresponding end face of the electrode assembly. In addition, a relief valve is configured on one or both end walls of the housing to facilitate opening of the relief valve to discharge internal substances of the battery when thermal runaway occurs in the battery. However, the current collecting member blocks the discharge of hot gas inside the battery, so that there is not enough internal pressure to burst the relief valve, resulting in the occurrence of the burst phenomenon and a great safety hazard. SUMMARY

[0004] The utility model provides a kind of secondary battery and electronic device to improve the technical problem that battery is prone to burst when thermal runaway occurs.

[0005] To achieve the above object and other related purposes, the utility model provides a kind of secondary battery and electronic device, the secondary battery includes: housing, electrode assembly, end cover and current collecting member;The housing includes circumferential side wall, and the side wall is formed with opening in one end;The electrode assembly is contained in the housing;End cover covers and seals opening, and the end cover is provided with weak part, and the weak part is configured to break when the pressure in the housing exceeds threshold value;Current collecting member is located between end cover and electrode assembly, and end cover and electrode assembly are electrically connected by current collecting member;Current collecting member is provided with multiple convex parts protruding towards end cover, and multiple convex parts are formed with recess on the side facing electrode assembly, and each convex part is provided with through hole.

[0006] In the above technical solution, multiple convex parts are provided on the current collecting member, and through holes are provided on the convex parts, which is beneficial to guide hot gas to discharge from the through holes when the battery is pressure released, reduce the block of current collecting member, so as to realize that there is enough pressure to burst the weak part on the end cover, realize pressure relief at the end cover, and reduce the safety hazard of battery burst.

[0007] In addition, the convex part also has the effect of strengthening the structural strength of the current collecting member, improving the flatness of the current collecting member, and further improving the stable reliability of the connection between the current collecting member and the electrode assembly.

[0008] In an example of the secondary battery of the utility model, along the height direction of the secondary battery, the projection of each convex part partially coincides with the weak part.

[0009] In the technical scheme, the projection of the convex part is partially coincident with the weak part, on the one hand, the effect of guiding the hot gas to the weak part can be achieved, and it is more beneficial to tear the weak part when the battery is pressure released, so that the pressure release at the end wall is realized, on the other hand, when the battery is in a vibration working condition, the convex part can be in contact with the weak part of the end cover, and the effect of protecting the weak part is achieved.

[0010] In the secondary battery example of the utility model, the convex part comprises a top surface and a side surface surrounding the top surface, and a plurality of through holes are arranged on the side surface.

[0011] In the technical scheme, a plurality of through holes are arranged on the side surface of the convex part, which is beneficial to tear the convex part when the battery is pressure released, and both the advantage of improving the structural strength of the convex part and the hidden danger of affecting pressure release due to too high strength are utilized.

[0012] In the secondary battery example of the utility model, under the vibration working condition, the top surface can be in contact with the side of the end cover facing the electrode assembly, so as to limit the displacement of the electrode assembly along the axial direction of the secondary battery.

[0013] In the technical scheme, the convex part can play a supporting effect between the end cover and the electrode assembly, and the vibration resistance of the components is improved.

[0014] In the secondary battery example of the utility model, the top surface is in abutment with the side of the end cover facing the electrode assembly.

[0015] In the technical scheme, the abutment of the top surface and the end cover can further improve the supporting effect of the convex part between the end cover and the electrode assembly, and then improve the anti-vibration performance of the components in the battery and the protection effect of the weak part on the end cover.

[0016] In the secondary battery example of the utility model, the electrode assembly comprises a tab facing the opening, the current collecting member comprises a plurality of tab connecting parts welded with the tab, the plurality of tab connecting parts are arranged at intervals along the circumferential direction of the current collecting member, and the convex part is arranged in an interval region between the two adjacent tab connecting parts.

[0017] In the technical scheme, the convex part is arranged in the interval region between the two adjacent tab connecting parts, on the one hand, the welding effect of the tab connecting part can be prevented from being affected, and on the other hand, the planeness of the electrode assembly can be further improved, the welding of the tab connecting part and the tab is facilitated, and then the reliability and stability of the welding are improved.

[0018] In the secondary battery example of the utility model, a plurality of notches are arranged on the outer periphery of the current collecting member, the notches are formed by inwardly recessing part of the outer periphery of the current collecting member, and the notches and the convex part are arranged in a staggered manner along the circumferential direction of the current collecting member.

[0019] In the above technical solution, when the battery is pressure released, the gap can guide the internal hot gas to enter between the end cover and the current collecting member along the inner wall of the shell through the gap, reduce the block of the current collecting member, facilitate to break the weak part on the end cover, realize the pressure release at the end cover, and reduce the safety hazard of the battery burst.

[0020] In the secondary battery example of the utility model, the current collecting member includes an end cover connecting part welded with the end cover, the end cover connecting part is arranged around the center of the current collecting member, and the projection of the end cover connecting part falls into the weak part along the height direction of the secondary battery and towards the end cover.

[0021] In the above technical solution, the end cover connecting part is arranged within the weak part, so that the end cover connecting part can prevent the hot gas from the gap from being blocked after being welded with the end cover, and the problem of weakening the internal pressure acting on the weak part is solved.

[0022] In the secondary battery example of the utility model, the outer periphery of the end cover is provided with a recessed part recessed towards the electrode assembly, the outer side of the recessed part is surrounded by a limiting part, the limiting part extends towards the radial outer side of the end cover and is fixedly connected with the end face of the opening, the recessed part includes a bottom wall facing the current collecting member, and a gap exists between the bottom wall and the current collecting member.

[0023] In the above technical solution, the recessed part is arranged to play a positioning role when the end cover and the shell are installed, and to block the laser when the end cover and the end face of the opening are welded; the gap between the bottom wall of the recessed part and the current collecting member can avoid the block of the hot gas coming along the inner wall of the shell by the recessed part when the secondary battery is pressure released, facilitate the smooth flow of the hot gas, facilitate to break the weak part on the end cover, and realize the pressure release at the end cover.

[0024] The utility model also provides an electronic device, the electronic device includes a battery pack, and the battery pack includes the secondary battery of any one of the above.

[0025] The secondary battery of the utility model is provided with a plurality of convex parts on the current collecting member, and a through hole is arranged on the convex part, which is conducive to guiding the hot gas to discharge from the through hole when the battery is pressure released, reducing the block of the current collecting member, so as to realize that the weak part on the end cover is broken by sufficient pressure, realize the pressure release at the end cover, and reduce the safety hazard of the battery burst.

[0026] In addition, the convex part also has the effect of strengthening the structural strength of the current collecting member, improving the flatness of the current collecting member, and further improving the stability and reliability of the connection between the current collecting member and the electrode assembly. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other embodiments can also be obtained from these drawings without creative labor.

[0028] Figure 1 It is a whole structure schematic view of a secondary battery embodiment of the present application.

[0029] Figure 2 It is a structure schematic view of an electrode assembly of a secondary battery embodiment of the present application.

[0030] Figure 3 It is Figure 1 It is a partial enlarged view of A in an embodiment.

[0031] Figure 4 It is Figure 1 It is a partial enlarged view of A in an embodiment.

[0032] Figure 5 It is a partial sectional view of a secondary battery embodiment of the present application.

[0033] Figure 6 It is Figure 5 It is a partial enlarged view of B.

[0034] Figure 7 It is a front view of a current collecting member of a secondary battery embodiment of the present application.

[0035] Figure 8 It is a structure schematic view of a current collecting member of a secondary battery embodiment of the present application.

[0036] Figure 9 It is a front view of a current collecting member of another secondary battery embodiment of the present application.

[0037] Figure 10 It is a structure schematic view of a current collecting member of another secondary battery embodiment of the present application.

[0038] Figure 11 It is a schematic view of a battery pack in an embodiment of an electronic device of the present application.

[0039] Figure 12 It is a schematic view in an embodiment of an electronic device of the present application.

[0040] Element number explanation

[0041] 1. Electronic device; 10. Battery pack; 11. Working part; 101. Box body; 102. Box cover; 100. Secondary battery; 110. Housing; 111. End wall; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. First tab; 1211. Negative current collector; 1212. First coating area; 1213. First uncoated area; 122. Separator; 123. Second tab; 1231. Positive current collector; 1232. Second coating area; 1233. Second uncoated area; 124. First tab; 125. Second tab; 130. Current collecting member; 131. Protrusion; 1311. Top surface; 1312. Side surface; 132. Through hole; 133. Tab connecting portion; 134. Spacing area; 135. Notch; 136. End cover connecting portion; 140. End cover; 141. Weak portion; 142. Concave portion; 1421. Bottom wall; 143. Limiting portion; 150. Pole. DETAILED DESCRIPTION

[0042] The above and other advantages and effects of the present application will become readily apparent to those of ordinary skill in the art from the following description in conjunction with the accompanying drawings. The present application can also be applied or implemented in other different embodiments, and various modifications or changes can be made to the details of the application based on different viewpoints and applications without departing from the spirit of the application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present application are intended to describe specific embodiments, and are not intended to limit the scope of protection of the present application. The test methods in the following embodiments are not specified, and are generally performed under conventional conditions or under conditions recommended by the manufacturers.

[0043] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified by the present application, each numerical range has two endpoints and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are consistent with the understanding of the prior art by those skilled in the art and the description of the present application. Any method, device and material of the prior art similar or equivalent to the method, device and material of the embodiments of the present application can also be used to realize the present application.

[0044] It should be understood that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the specification are only for the convenience of clear description, and are not intended to limit the scope of the present application. The change or adjustment of the relative relationship without substantial change of the technical content is also regarded as the scope of the present application.

[0045] The secondary battery includes an electrode assembly, which is a component in which electrochemical reactions occur in the secondary battery, and can include one or more electrode assemblies.

[0046] The secondary battery further includes a case, an end cover, and a current collecting member, the case including an end wall and a side wall surrounding the end wall, one end of the side wall having an opening, the electrode assembly being assembled into the case via the opening of the case, the end cover being used to cover the opening of the case to achieve sealing, the case and the electrode assembly being electrically connected through the current collecting member, and in addition, an explosion-proof valve is configured on one or both end walls of the case to facilitate opening of the explosion-proof valve to discharge internal substances of the battery when thermal runaway occurs in the battery.

[0047] However, the inventor finds that the current collecting member blocks the discharge of hot gas inside the battery, so that there is not enough internal pressure to blow open the explosion-proof valve, resulting in the occurrence of the phenomenon of burst chamber, which has great safety hazards.

[0048] In view of this, the utility model provides a technical scheme, a plurality of convex parts are arranged on the current collecting member, and through holes are arranged on the convex parts, which is beneficial to guiding the hot gas to be discharged from the through holes when the battery is pressure released, reducing the blockage of the current collecting member, so as to realize that there is enough pressure to blow open the weak part on the end cover, realize the pressure release at the end cover, and reduce the safety hazards of the occurrence of the battery burst chamber.

[0049] Please refer to Figures 1 to 12 The utility model provides a secondary battery 100 and electronic device 1, the secondary battery 100 includes: case 110, electrode assembly 120, current collecting member 130, end cover 140 and pole 150.

[0050] Please refer to Figure 1The shell 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. The connection between the end wall 111 and the side wall 112 can be achieved in various ways, such as one-piece stamping, one-piece casting, or separate welding, as long as a stable sealing and electrical connection relationship can be formed. The surrounding of the side wall 112 is not limited, and can be cylindrical or prismatic, or any other closed-loop profile that can match the end wall 111. In the 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. A circular opening 113 is formed at the end of the side wall 112 away from the end wall 111. The shell 110 formed by the end wall 111 and the side wall 112 has a receiving cavity for accommodating the electrode assembly 120, electrolyte, and other necessary components of the battery. Specifically, the diameter of the shell 110 can be determined according to the specific size of the electrode assembly 120, such as 18 mm, 21 mm, 46 mm, etc. The shell 110 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. To prevent rusting of the shell 110 during long-term use, a layer of anti-rust material such as metal nickel can be plated on the surface of the shell 110.

[0051] Referring to Figures 1 to 2 The electrode assembly 120 is accommodated in the shell 110, and is a component of the secondary battery 100 where electrochemical reactions occur. The shell 110 can contain one or more electrode assemblies 120. The electrode assembly 120 includes a first electrode tab 121, a second electrode tab 123, and a separator 122 stacked and wound to form a wound structure. The first electrode tab 121 and the second electrode tab 123 have opposite polarities. In some embodiments, the first electrode tab 121 is a positive electrode tab, and the second electrode tab 123 is a negative electrode tab. In other embodiments, the first electrode tab 121 is a negative electrode tab, and the second electrode tab 123 is a positive electrode tab.

[0052] Referring to Figures 1 to 2 In the embodiment, the first electrode tab 121 is a negative electrode tab. The first electrode tab 121 includes a negative electrode current collector 1211 and a negative electrode active material coated on the surface of the negative electrode current collector 1211. The negative 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 tab 121, and extends beyond the separator 122 along the winding axis direction of the electrode assembly 120 and bends towards the winding axis to form a first electrode lug 124, which is a corresponding negative electrode lug.

[0053] Referring to Figures 1 to 2The second tab 123 is a positive electrode tab. Specifically, the second tab 123 includes a positive electrode current collector 1231 and a positive electrode active material coated on a surface of the positive electrode current collector 1231. The positive electrode current collector 1231 includes a second coated area 1232 coated with the active material and a second uncoated area 1233 uncoated with the active material. The second uncoated area 1233 is located at an end of the second tab 123, extends out of the separator 122 along the winding axis direction of the electrode assembly 120, and is bent towards the winding axis to form a second tab 125. The second tab 125 is a corresponding positive electrode tab.

[0054] Referring to Figures 1 to 2 The separator 122 is arranged between the first tab 121 and the second tab 123 to separate the positive electrode active material layer and the negative electrode active material layer. For example, in the lithium ion secondary battery 100, the material of the positive electrode current collector 1231 can be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate. The material of the negative electrode current collector 1211 can be copper, the negative electrode active material layer includes a negative electrode active material, 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). To protect and insulate the electrode assembly 120, an insulating film can be wrapped outside the electrode assembly 120. The insulating film can be made of PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other high polymer materials.

[0055] Referring to Figure 1 and Figure 2 Further, the first tab 124 faces the end wall 111 or the opening 113, and the second tab 125 faces the other end of the housing 110. In this embodiment, the second tab 125 faces the end wall 111 and is electrically connected to the pole 150 to make the pole 150 positively charged. The tab facing the opening 113 is the first tab 124, and the housing 110 is electrically connected to the first tab 124 to be negatively charged. However, in another embodiment, the first tab 124 can be connected to the pole 150, and the second tab 125 can be connected to the housing 110.

[0056] Referring to Figure 1The pole post 150 is fixed to the end wall 111 and electrically connected with the electrode assembly 120. Specifically, the end wall 111 is provided with a pole post hole, the pole post 150 is installed through the pole post hole, and the end wall 111 is insulated. The end of the pole post 150 towards the electrode assembly 120 is directly electrically connected with the second pole lug 125 through the end wall 111 or indirectly electrically connected through an indirect adapter. The structure of the pole post 150 can be any suitable form that can be electrically connected with the second pole lug 125 of the electrode assembly 120 through the end wall 111, such as a circular cross-section, a square cross-section, a prism cross-section, or a special-shaped profile that can achieve stable conduction. The pole post hole corresponds to the shape of the pole post 150. In the embodiment, the cross-section of the pole post 150 is circular.

[0057] Referring to Figures 1 to 6 The end cover 140 covers and seals the opening 113. The end cover 140 is provided with a weak part 141 configured to break when the pressure in the shell 110 exceeds a threshold value. Specifically, the shape of the weak part 141 can be a closed or open curve, a polygon, or an irregular shape. The weak part 141 can be, for example, a notch provided on the surface of the end cover 140. It should be understood that in other embodiments, the weak part 141 can also be replaced by other brittle structures, such as changing the material of the weak part 141 to have a lower structural strength than other areas of the end cover 140. The weak part 141 in the embodiment is a closed annular notch. The thickness of the notch position changes suddenly, so when the end cover 140 is stressed, the end cover 140 will first break at the notch due to stress concentration, the pressure relief area will fall off to form a discharge port, and the internal material will be guided to discharge from the discharge port, thereby avoiding explosion of the secondary battery 100.

[0058] Referring to Figure 3 and Figure 6 The current collecting member 130 is located between the end cover 140 and the electrode assembly 120, and the end cover 140 and the electrode assembly 120 are electrically connected through the current collecting member 130. In a specific embodiment, the current collecting member 130 is welded with the first pole lug 124. The welding method can be ultrasonic welding, resistance welding, laser welding, etc., which is not limited. In the embodiment, laser welding is adopted, the first pole lug 124 is a negative pole lug, and the material of the current collecting member 130 is preferably copper metal. It should be noted that the shape of the current collecting member 130 can be any shape of rotational symmetry, such as a circular shape, a square shape, a regular polygon shape, a petal shape, or other shapes having a center of symmetry and being able to coincide with the original shape after rotating around the center of symmetry by a certain angle. The center of the current collecting member 130 is the center of symmetry thereof. In order to improve the positioning, processing convenience, interchangeability, and uniformity of the current collecting member 130 during installation, the current collecting member 130 in the embodiment adopts a circular structure.

[0059] Further, please refer to Figure 3 and Figure 10 The current collector member 130 is provided with a plurality of convex portions 131 protruding towards the end cover 140. The convex portions 131 can be integrally formed by stamping, can be formed by casting, or can be obtained by machining the current collector member 130 to remove material. In an embodiment of the secondary battery 100, the convex portions 131 are obtained by stamping. The plurality of convex portions 131 are formed with recesses on the side facing the electrode assembly 120. The stamping method can form the recesses without causing material waste. The convex portions 131 also have the effect of strengthening the structural strength of the current collector member 130, improving the flatness of the current collector member 130, and further improving the stability and reliability of the connection between the current collector member 130 and the electrode assembly 120. In addition, since there is no binding force in the winding hole of the winding structure, when the secondary battery 100 is charging or discharging, the winding hole of the winding structure will appear to be drawn out under the action of the radial outside compression force. The support of the convex portions 131 can improve the problem of the winding structure being drawn out.

[0060] It should be noted that the number of convex portions 131 is not limited, and can be 2, 4, 6, or more. The arrangement of the plurality of convex portions 131 is also not limited, and can be arranged along the circumference of the current collector member 130, or can be arranged horizontally and vertically. The shape of the convex portions 131 is also not limited, and can be circular, square, oval, polygonal, or other irregular shapes. In an embodiment, please refer to Figure 7 and Figure 8 The convex portions 131 are provided with 4 rectangular convex portions 131, which are arranged in a circumferential direction around the axis of the current collector member 130. In another embodiment, the convex portions 131 are oval, please refer to Figure 9 and Figure 10 .

[0061] Considering that the current collector member 130 blocks the discharge of hot gas inside the battery, so that there is not enough internal pressure to blow open the explosion-proof valve, resulting in the phenomenon of explosion. Further, each convex portion 131 is provided with a through hole 132. The number, size, and position of the through hole 132 are not limited, as long as it can pass through the current collector member 130, so that the hot gas in the electrode assembly 120 can pass through the through hole 132 into the space between the end cover 140 and the current collector member 130. For example, in an embodiment, please refer to Figure 7 and Figure 8 Each rectangular convex portion 131 is provided with two through holes 132, and the two through holes 132 are located at the two ends of the convex portion 131. In another embodiment, please refer to Figure 9 and Figure 10Each of the elliptical protrusions 131 is provided with four through holes 132, which are respectively arranged at the two ends in the length direction and the two ends in the width direction of the protrusion 131. The through holes 132 are beneficial to guiding the hot gas to be discharged from the through holes 132 when the battery is pressure released, reducing the obstruction of the current collecting member 130, so as to realize that the weak part 141 on the end cover 140 is punched by sufficient pressure, and the pressure release at the end cover 140 is realized, and the safety hazard of the battery explosion is reduced.

[0062] Referring to Figure 5 and Figure 6 In an example of the secondary battery 100 of the utility model, along the height direction of the secondary battery 100, the projection of each protrusion 131 is partially coincident with the weak part 141. The setting can guide the hot gas to the weak part 141, and is more beneficial to tearing the weak part 141 when the battery is pressure released, so as to realize the pressure release at the end wall 111. Preferably, in some embodiments, when the battery is in a vibration working condition, the protrusion 131 can be in contact with the weak part 141 of the end cover 140, and plays a certain supporting role, and plays a protective effect on the weak part 141.

[0063] Referring to Figure 3 In an example of the utility model secondary battery 100, the protrusion 131 includes a top surface 1311 and a side surface 1312 surrounding the top surface 1311, preferably, the side surface 1312 and the top surface 1311 are connected by a circular arc, and the side surface 1312 and the body of the current collecting member 130 are also connected by a circular arc. The setting can reduce the stress concentration of the corner part of the protrusion 131, so as to improve the structural strength of the protrusion 131. Further, a plurality of through holes 132 are arranged on the side surface 1312. It can be understood that the through holes 132 can be arranged only on the side surface 1312, or can be arranged on the side surface 1312 and the top surface 1311, which is not limited, and the number of through holes 132 is not limited. For example, in an embodiment, four through holes 132 are arranged on the side surface 1312 of each protrusion 131, which are respectively arranged at the two ends in the length direction and the two ends in the width direction of the protrusion 131. The setting is beneficial to tearing at the protrusion 131 when the battery is pressure released, which not only utilizes the advantage that the protrusion 131 can improve the structural strength, but also improves the hidden danger that the strength is too high to affect the pressure release.

[0064] Referring to Figure 4 In an example of the utility model secondary battery 100, under the vibration working condition, the top surface 1311 can be in contact with the side of the end cover 140 facing the electrode assembly 120, so as to limit the displacement of the electrode assembly 120 along the axial direction of the secondary battery 100. The protrusion 131 in the embodiment can play a supporting effect between the end cover 140 and the electrode assembly 120, and can improve the vibration resistance of each component.

[0065] Preferably, referring to Figure 4In the secondary battery 100 example of the utility model, the top surface 1311 and the side of the end cover 140 facing the electrode assembly 120 abut. This arrangement can further improve the supporting effect of the convex part 131 between the end cover 140 and the electrode assembly 120, thereby improving the anti-shock performance of the components in the battery and improving the protection effect on the weak part 141 of the end cover 140.

[0066] Please refer to Figures 6 to 10 In the secondary battery 100 example of the utility model, the current collecting member 130 includes a plurality of tab connecting parts 133 welded with the tabs, and the plurality of tab connecting parts 133 are arranged at intervals along the circumference of the current collecting member 130. The number of tab connecting parts 133 can be 2, 3, 4, 5, 6 or more. In some embodiments, please refer to Figures 7 to 10 The tab connecting part 133 has 4, and the 4 tab connecting parts 133 are arranged uniformly in a circumferential direction with the center of the current collecting member 130 as the center. The above arrangement can facilitate uniform distribution of current through the first tab 124, reduce internal resistance and heat generation, thereby enhancing the performance of the secondary battery 100, and also improving the welding strength. It can be understood that: the interval area 134 between every two adjacent tab connecting parts 133 is a non-welding area, and the convex part 131 is arranged in the interval area 134 between the two adjacent tab connecting parts 133. On the one hand, it can avoid the tab connecting part 133 to prevent affecting the welding effect of the tab connecting part 133, and on the other hand, it can further improve the flatness of the electrode assembly 120, which is conducive to the welding of the tab connecting part 133 and the tab, thereby improving the reliable stability of the welding. Preferably, the interval area 134 between each adjacent tab connecting part 133 is provided with a convex part 131, which can realize the same shape and mass distribution, uniform stiffness distribution and uniform stress, so that the current collecting member 130 has high stiffness, and is conducive to improving the flatness of the current collecting member 130, thereby improving the stable reliability of the connection between the current collecting member 130 and the electrode assembly 120.

[0067] Please refer to Figure 9 And Figure 10 In the secondary battery 100 example of the utility model, a plurality of notches 135 are arranged on the outer periphery of the current collecting member 130. The notch 135 is formed by inwardly recessing part of the outer periphery of the current collecting member 130. The number and shape of the notch 135 are not limited. Only when the battery is relieved, the internal hot gas can be guided to enter between the end cover 140 and the current collecting member 130 through the notch 135 along the inner wall of the shell 110, thereby reducing the obstruction of the current collecting member 130, facilitating the breaking of the weak part 141 on the end cover 140, and achieving pressure relief at the end cover 140, thereby reducing the safety hazard of battery burst. Preferably, the notch 135 and the convex part 131 are arranged staggered along the circumference of the current collecting member 130. In an embodiment, please refer to Figure 9 AndFigure 10 The four notches 135 are U-shaped, and are arranged on the outer periphery of the four tab connecting portions 133 extending radially outward of the current collecting member 130, and are staggered with the convex portions 131, which is beneficial to the uniformity of the hot gas guiding, optimizes the distribution of the internal pressure on the weak portion 141, and further improves the safety performance of the battery.

[0068] Please refer to Figures 7 to 10 In an example of the secondary battery 100, the current collecting member 130 includes a cover connecting portion 136 welded with the end cover 140, and the shape of the cover connecting portion 136 includes a circle, a square, a circular ring or a square ring, but is not limited to the above, preferably, the cover connecting portion 136 is arranged around the center of the current collecting member 130, which can realize reliable welding between the current collecting member 130 and the end cover 140, and the projection of the cover connecting portion 136 falls into the weak portion 141 along the height direction of the secondary battery 100 towards the end cover 140. This arrangement can prevent the cover connecting portion 136 from blocking the hot gas from the notches 135 after being welded with the end cover 140, and can realize smooth drainage of the hot gas to the weak portion 141 when the secondary battery 100 is pressure released, so as to realize the rupture of the weak portion 141 on the end cover 140 under sufficient pressure.

[0069] Please refer to Figures 3 to 6In the secondary battery 100 example of the utility model, the outer periphery of the end cover 140 is provided with a recess 142 recessed towards the electrode assembly 120, the outer side of the recess 142 is surrounded by a limiting portion 143, the limiting portion 143 extends towards the radial outer side of the end cover 140 and is fixedly connected with the end face of the opening 113, the recess 142 includes a bottom wall 1421 facing the current collecting member 130, it can be understood that the recess 142 surrounds the outer periphery of the end cover 140, not limited to the case that the end cover 140 is circular, for example, the end cover 140 is square or polygonal, the recess 142 can be corresponding square or polygonal, preferably, the outer edge of the recess 142 cooperates with the side wall 112, the recess 142 can be used as the assembly guide of the end cover 140 and the opening 113, which is beneficial to the cooperation of the side wall 112 of the shell 110 and the end cover 140, the setting can make the end cover 140 and the opening 113 quickly positioned along the circumference, thereby improving the efficiency of welding and the radial position accuracy of welding, meanwhile, the recess 142 also has the effect of blocking laser when welding the end face of the end cover 140 and the opening 113. The connecting mode between the recess 142 and the end cover 140 is not limited, which can be integrally stamped, or can be obtained by machining on the end cover 140 to remove materials, in the secondary battery 100 example of the utility model, the recess 142 is obtained by stamping, the side of the recess 142 away from the electrode assembly 120 is formed as a recess, the stamping mode can form the recess without causing material waste, in some examples, there is a gap between the bottom wall 1421 and the current collecting member 130. When the secondary battery 100 is pressure released, the recess 142 can avoid blocking the hot gas coming along the inner wall of the shell 110, which is beneficial to the smooth flow of the hot gas and the breaking of the weak portion 141 on the end cover 140, thereby achieving pressure release at the end cover 140.

[0070] Please refer to Figure 12 The utility model also provides an electronic device 1, electronic device 1 includes battery pack 10. Please refer to Figure 11 Battery pack 10 includes the secondary battery 100 of any one of the above, in the battery pack 10 example of the utility model, battery pack 10 includes box 101, box cover 102 and multiple secondary batteries 100, multiple secondary batteries 100 are placed in box 101, are connected in series or parallel with each other, or series and parallel hybrid, and the box cover 102 is capped on the box 101 to protect multiple secondary batteries 100. It needs to be explained that battery pack 10 can also include battery pack 10 thermal management system, circuit board and other parts in addition to the secondary battery 100 of the utility model, battery pack 10 can be battery module or battery pack, energy storage cabinet etc.;Here will not be expanded one by one.

[0071] Further, please refer to Figure 12The working part 11 is electrically connected with the battery pack 10 to obtain electric energy support. As an example, the electronic device 1 is a vehicle, which can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric vehicle, a hybrid vehicle or a range extended vehicle, but is not limited thereto. The working part 11 is a vehicle body, and the battery pack 10 is arranged at the bottom of the vehicle body and provides electric energy support for driving of the vehicle or operation of electrical elements in the vehicle. However, in some other embodiments, the electronic device 1 can also be a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The working part 11 can be a unit component capable of obtaining electric energy of the battery pack 10 and making corresponding work, such as a fan blade rotating unit, a dust suction working unit of a dust collector, etc. The electric toy includes a fixed or mobile electric toy, such as a game machine, an electric car toy, an electric ship toy and an electric plane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not specially limit the above-mentioned electronic device 1.

[0072] The secondary battery of the utility model discloses a plurality of convex parts are arranged on the current collecting member, and a through hole is arranged on the convex part, which is beneficial to guiding hot gas to discharge from the through hole when the battery is pressure released, reducing the block of the current collecting member, so that the weak part on the end cover is broken by sufficient pressure, the pressure release at the end cover is realized, and the safety hazard of the battery burst is reduced. Therefore, the utility model effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance. The above-mentioned embodiments only exemplarily illustrate the principle and effect of the utility model, and are not used for limiting the utility model. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the utility model should be covered by the claims of the utility model.

Claims

1. A secondary battery characterized by comprising: The application relates to a secondary battery, comprising: a shell comprising a circumferential side wall, one end of the side wall being provided with an opening; an electrode assembly accommodated in the shell; an end cover covering and sealing the opening, the end cover being provided with a weak part configured to break when the pressure in the shell exceeds a threshold value; a current collecting member between the end cover and the electrode assembly, the end cover and the electrode assembly being electrically connected through the current collecting member; wherein the current collecting member is provided with a plurality of protrusions protruding towards the end cover, the plurality of protrusions being provided with recesses on a side facing the electrode assembly, and each of the protrusions is provided with a through hole.

2. The secondary battery according to claim 1, characterized by In the height direction of the secondary battery, the projection of each of the protrusions on the end cover partially overlaps the weak part.

3. The secondary battery according to claim 2, characterized by The protrusion comprises a top surface and a side surface surrounding the top surface, and the side surface is provided with a plurality of through holes.

4. The secondary battery according to claim 3, characterized by In a vibration working condition, the top surface can contact a side of the end cover facing the electrode assembly to limit the displacement of the electrode assembly in the axial direction of the secondary battery.

5. The secondary battery according to claim 4, characterized by The top surface abuts against the side of the end cover facing the electrode assembly.

6. The secondary battery according to claim 1, characterized by The electrode assembly comprises a tab facing the opening, the current collecting member comprises a plurality of tab connecting parts welded with the tab, the plurality of tab connecting parts are arranged at intervals in the circumferential direction of the current collecting member, and the protrusion is arranged in an interval region between two adjacent tab connecting parts.

7. The secondary battery according to claim 6, characterized by The outer periphery of the current collecting member is provided with a plurality of notches, the notches are formed by inwardly recessing part of the outer periphery of the current collecting member, and the notches and the protrusions are arranged at intervals in the circumferential direction of the current collecting member.

8. The secondary battery according to claim 7, characterized by The current collecting member comprises an end cover connecting part welded with the end cover, the end cover connecting part is arranged around the center of the current collecting member, and the projection of the end cover connecting part on the end cover falls into the weak part in the height direction of the secondary battery.

9. The secondary battery according to claim 8, characterized by The outer periphery of the end cover is provided with a recess recessed towards the electrode assembly, the outer side of the recess is surrounded by a limiting part extending towards the radial outer side of the end cover and fixedly connected with the end surface of the opening, and the recess comprises a bottom wall facing the current collecting member, and a gap exists between the bottom wall and the current collecting member.

10. An electronic device, comprising: The application further relates to a battery pack comprising the secondary battery.

Images