An energy storage device

Abstract

The present application relates to an energy storage device, which includes a first current collecting disc, an insulating member, an end cover, a plastic member and a wound electrode assembly. The first current collecting disc cover is arranged at one end of the wound electrode assembly, and a first welding ring is arranged on the side of the first current collecting disc away from the wound electrode assembly; the pole ear is connected to the first current collecting disc and is used to draw out current; the insulating member is arranged on the side of the first current collecting disc away from the wound electrode assembly, and at least part of the insulating member is spaced apart from the first current collecting disc; the end cover is arranged on the side of the insulating member away from the wound electrode assembly, and a second welding ring is arranged between the end cover and the insulating member; at least part of the plastic member is sandwiched between the first welding ring and the second welding ring, and the plastic member is provided with a barb portion, which abuts against the portion where the insulating member and the first current collecting disc are spaced apart, and is used to prevent the insulating member from moving in a direction close to the wound electrode assembly. The energy storage device described in the present application has the advantage of preventing the first current collecting disc and the end cover from overlapping and short-circuiting to maintain a good insulation effect.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an energy storage device. Background Art

[0002] Rechargeable batteries, also known as rechargeable batteries or storage batteries, are batteries that can be recharged to activate the active materials and continue to be used after being discharged. The recyclable nature of secondary batteries has made them gradually become the main power source for electrical equipment. As the demand for secondary batteries gradually increases, people have higher requirements for their energy density, reliability and cost.

[0003] Traditional secondary batteries use the pole lugs to draw current from the wound electrode assembly. The current collector is a device used to enhance the performance of drawing current. The traditional current collector has a multi-layer structure and needs to be folded by pressing down the end cover during assembly. The folding of the current collector has a certain probability of causing the top cover and the shell to be misaligned and scraped out aluminum wire, causing the wound electrode assembly to short-circuit and catch fire, and is prone to internal short circuits. Summary of the invention

[0004] Based on this, it is necessary to provide an energy storage device to address the problem that the end cap and the current collecting plate of the secondary battery are prone to overlapping and short-circuiting.

[0005] The present application provides an energy storage device, comprising:

[0006] A wound electrode assembly for storing electricity;

[0007] A first current collecting disk, covering one end of the wound electrode assembly, wherein a first welding ring is provided on a side of the first current collecting disk away from the wound electrode assembly;

[0008] A pole ear connected to the first current collecting plate, and the pole ear is used to draw out current;

[0009] an insulating member, disposed on a side of the first current collecting disk away from the wound electrode assembly, at least a portion of the insulating member being spaced apart from the first current collecting disk;

[0010] an end cap, arranged on a side of the insulating member away from the wound electrode assembly, wherein a second welding ring is arranged between the end cap and the insulating member;

[0011] A plastic part, at least part of which is sandwiched between the first welding ring and the second welding ring, and the plastic part is provided with a barb portion, which abuts against a portion where the insulating part and the first current collecting disk are spaced apart, and the barb portion is used to prevent the insulating part from moving in a direction close to the wound electrode assembly.

[0012] In one embodiment, the end cover is provided with a protrusion, and the plastic part is provided with an extension, the extension corresponds to the protrusion, and at least a portion of the extension is located between the inner wall of the protrusion and the first welding ring.

[0013] In one embodiment, the insulating member includes a plate portion and a ridge portion connected to the plate portion, the ridge portion contacts a side of the first current collecting disk away from the wound electrode assembly, so that the plate portion is spaced apart from the first current collecting disk.

[0014] In one embodiment, the first current collecting disk is provided with a welding area and a disk surface area, and the first current collecting disk is formed with a sinking portion recessed toward the direction of the wound electrode assembly in the welding area, and the electrode ear is connected to a side of the sinking portion away from the wound electrode assembly.

[0015] In one of the embodiments, the first current collecting disk is provided with a first step portion, the first step portion protrudes in a direction away from the wound electrode assembly, the first welding ring is connected to the first step portion, and the first step portion is also used for welding the pole piece.

[0016] In one embodiment, the end surface of the first step portion is circular, and the diameter of the first step portion is 2 mm to 10 mm larger than the diameter of the pole piece.

[0017] In one embodiment, the plastic part is provided with a limiting block, the insulating part is provided with a first positioning hole, the second welding ring is provided with a second positioning hole, and the limiting block extends in a direction close to the wound electrode assembly and penetrates into the second positioning hole and the first positioning hole in sequence.

[0018] In one embodiment, the energy storage device further includes a shell and a positive electrode column, one end of the shell is formed with an opening, the end cover is covered on the shell and closes the opening, and the positive electrode column is connected to the first current collecting plate.

[0019] In one embodiment, the energy storage device further comprises a second current collecting disk and a negative electrode pole, the second current collecting disk being arranged at one end of the wound electrode assembly away from the first current collecting disk, the second current collecting disk being provided with a second step portion, the second step portion protruding in a direction away from the wound electrode assembly, the negative electrode pole being connected to the second step portion, the diameter of the second step portion being 2 mm to 10 mm larger than the diameter of the negative electrode pole, and a through hole being provided at one end of the shell away from the opening, the diameter of the through hole being 0.5 mm to 1 mm larger than the diameter of the negative electrode pole.

[0020] In one embodiment, the first current collecting plate is a single-layer structure.

[0021] The energy storage device described above sandwiches a plastic part between the first welding ring and the second welding ring, and provides a barb portion on the plastic part. The barb portion provides support for the side of the insulating part close to the wound electrode assembly. The insulating part can be stably supported during the production and use of the energy storage device, preventing the insulating part from approaching the wound electrode assembly and causing the first current collecting disk and the end cover to overlap and short-circuit, thereby maintaining a good insulation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a half-section structure of an energy storage device in one embodiment of the present application.

[0023] Figure 2 for Figure 1 A magnified schematic diagram of center A.

[0024] Figure 3 It is a half-section exploded view of the first current collecting plate, insulating member, end cover and plastic member of the energy storage device in one embodiment of the present application.

[0025] Figure 4 for Figure 3 A magnified schematic diagram of point B in the middle.

[0026] Description of Figure Numbers:

[0027] 100, first current collecting disk; 100a, welding area; 100b, disk area; 110, first welding ring; 111, sinking part; 111a, first through hole; 120, sinking groove part; 130, first step part; 200, insulating part; 200a, first positioning hole; 210, plate part; 220, convex ridge part; 300, end cover; 310, second welding ring; 310a, second positioning hole; 320, raised part; 400, plastic part; 400a, second through hole; 410, barb part; 420, retaining wall; 430, extension part; 440, limit block; 500, wound electrode assembly; 600, pole part; 610, positive pole; 620, negative pole; 700, shell; 800, second current collecting disk. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0029] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0030] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0032] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0034] refer to Figures 1 to 4 , an energy storage device provided by an embodiment of the present application includes a first current collecting disc 100, an insulating member 200, an end cover 300, a plastic member 400 and a wound electrode assembly 500. The wound electrode assembly 500 is used for storing electricity, the first current collecting disc 100 is covered at one end of the wound electrode assembly 500, and a first welding ring 110 is provided on the side of the first current collecting disc 100 away from the wound electrode assembly 500; a pole ear (not shown) is connected to the first current collecting disc 100, and the pole ear is used to draw out current; the insulating member 200 is provided on the side of the first current collecting disc 100 away from the wound electrode assembly 500, and at least part of the insulating member 200 is spaced apart from the first current collecting disc 100; the end cover 300 A second welding ring 310 is arranged on the side of the insulating member 200 away from the wound electrode assembly 500, and a second welding ring 310 is arranged between the end cover 300 and the insulating member 200; at least a portion of the plastic member 400 is clamped between the first welding ring 110 and the second welding ring 310, and the plastic member 400 is provided with a barb portion 410, which abuts against the portion where the insulating member 200 and the first current collecting disk 100 are spaced apart, and the barb portion 410 is used to prevent the insulating member 200 from moving in a direction close to the wound electrode assembly 500.

[0035] The energy storage device described in the present application sandwiches a plastic part 400 between the first welding ring 110 and the second welding ring 310, and provides a barb portion 410 on the plastic part 400. The barb portion 410 provides support for the side of the insulating part 200 close to the wound electrode assembly 500. During the production and use of the energy storage device, the insulating part 200 can be stably supported to prevent the insulating part 200 from approaching the wound electrode assembly 500 and causing the first current collecting disk 100 and the end cover 300 to overlap and short-circuit, thereby maintaining a good insulation effect.

[0036] Specifically, the wound electrode assembly 500 in this embodiment is cylindrical and is the electricity storage part of the energy storage device. Figure 3 Taking the energy storage device shown in the figure as an example, when viewed from a top view, the first current collecting plate 100 , the insulating member 200 and the end cover 300 are circular, while the first welding ring 110 and the second welding ring 310 are square.

[0037] A sinking portion 111 is disposed in the middle of the first welding ring 110 . A first through hole 111 a is formed in the sinking portion 111 . The first through hole 111 a is used to pass the pole piece 600 , and can leave space for welding the pole piece 600 and the first current collecting plate 100 .

[0038] refer to Figure 2 The sinking portion 111 makes the cross section of the first welding ring 110 be in a folded shape. In this embodiment, the sinking portion 111 is used to be welded and fixed to the first current collecting plate 100 .

[0039] The plastic part 400 is provided with a second through hole 400a, which corresponds to the sinking part 111 and leaves space for placing the sinking part 111. The plastic part 400 is provided with a retaining wall 420, which surrounds the second through hole 400a, and the barb 410 is provided on a side of the retaining wall 420 away from the sinking part 111.

[0040] The first current collecting disc 100 is a metal disc with a certain elasticity, and is prone to a small amount of deformation during the use of the energy storage device and moves toward the wound electrode assembly 500. By providing the barb portion 410 on the plastic part 400, the movement of the insulating member 200 driven by the deformation of the first current collecting disc 100 can be reduced, thereby improving the structural stability of the entire energy storage device.

[0041] The electrode tab is a metal conductor that draws the current from the positive and negative electrodes from the wound electrode assembly 500. The number of electrode tabs can be one or more.

[0042] In some embodiments, the end cap 300 is provided with a protrusion 320 , and the plastic part 400 is provided with an extension 430 . The extension 430 corresponds to the protrusion 320 , and at least a portion of the extension 430 is located between the inner wall of the protrusion 320 and the first welding ring 110 .

[0043] For example, reference Figure 2 and Figure 3 The middle part of the end cover 300 protrudes upward to form a protrusion 320. When viewed from above, the protrusion is approximately square. Figure 2 Taking the plastic part 400 as an example, the extension part 430 is bent upward and arranged corresponding to the side wall of the protrusion 320, so that the cross section of the plastic part 400 is folded. It can be understood that the extension part 430 passes between the first welding ring 110 and the side wall of the protrusion 320, and the first welding ring 110 and the protrusion 320 can limit the extension part 430. Therefore, by arranging the extension part 430 between the first welding ring 110 and the protrusion 320 on the plastic part 400, the fixing and limiting effect of the plastic part 400 can be improved, thereby indirectly optimizing the supporting effect of the barb part 410 on the insulating part 200. Moreover, this fixing method replaces the connection methods such as bonding or welding, and is simple to operate and easy to replace.

[0044] A sealing ring (not marked in the figure) is provided on the side of the protrusion 320 facing the wound electrode assembly 500 to prevent leakage of electrolyte.

[0045] refer to Figure 2 In some embodiments, the insulating member 200 includes a plate portion 210 and a ridge portion 220 connected to the plate portion 210, and the ridge portion 220 contacts the side of the first current collecting disk 100 away from the wound electrode assembly 500, so that the plate portion 210 is spaced from the disk surface of the first current collecting disk 100, and a space is reserved for the barb portion 410 to abut against the plate portion 210. On the other hand, the ridge portion 220 also reduces the contact area between the insulating member 200 and the first current collecting disk 100, further improving the insulation between the insulating member 200 and the first current collecting disk 100, and then improving the safety of the energy storage device.

[0046] In some embodiments, the first current collecting disk 100 is provided with a welding area 100a and a disk surface area 100b. The first current collecting disk 100 is formed with a sink portion 120 recessed toward the direction of the wound electrode assembly 500 in the welding area 100a, and the electrode tab is connected to the side of the sink portion 120 away from the wound electrode assembly 500.

[0047] refer to Figure 3 , exemplarily, around the circumferential direction of the first current collecting disk 100, the first current collecting disk 100 is provided with a plurality of welding areas 100a, and the welding areas 100a are recessed in the direction where the wound electrode assembly 500 is located to form a sinking groove 120. In this embodiment, one end of the sinking groove 120 corresponds to the edge of the first current collecting disk 100, and the other end faces the center of the first current collecting disk 100. In this embodiment, a plurality of pole ears are respectively arranged on a plurality of sinking grooves 120 in a one-to-one correspondence, and are welded to the sinking grooves 120. By providing the sinking grooves 120, the reliability of the welding between the current collecting disk and the pole ears is increased, and the range of action of each pole ear and the wound electrode assembly 500 is more concentrated, thereby improving the current passing capacity of the first current collecting disk 100 to the current, and optimizing the continuous discharge performance of the energy storage device.

[0048] It can be understood that in this embodiment, the welding area 100a and the disk area 100b are arranged at intervals in the circumferential direction of the first current collecting disk 100, so that the flow of the first current collecting disk 100 can be more uniform. Optionally, the welding area 100a and the disk area 100b are evenly spaced, and the flow uniformity is better. In other embodiments, the shape and distribution uniformity of the welding area 100a can also be determined according to actual requirements.

[0049] In some embodiments, reference Figure 2 and Figure 3, the first current collecting disc 100 is provided with a first step portion 130, the first step portion 130 protrudes in a direction away from the wound electrode assembly 500, and the first welding ring 110 is connected to the first step portion 130. Exemplarily, the first step portion 130 is located at the center of the first current collecting disc 100, and opposite to the sink portion 120, the first step portion 130 protrudes in a direction away from the wound electrode assembly 500 to form a gap with the wound electrode assembly 500. Since the first current collecting disc 100 is a metal disc and has a certain elasticity, it can be understood that the gap between the first step portion 130 and the wound electrode assembly 500 can make the first current collecting disc 100 have a greater elastic deformation freedom at the center, reduce the extrusion strength of the pole piece 600 on the wound electrode assembly 500 when the energy storage device is in use, and reduce the probability of circuit occurrence.

[0050] In some embodiments, the end surface of the first step portion 130 is circular, and the diameter of the first step portion 130 is 2 mm to 10 mm larger than the diameter of the pole piece 600. In this way, the circular end surface of the first step portion 130 can help locate the pole piece 600, so that the pole piece 600 is aligned with the center of the first current collecting plate 100 as much as possible; the diameter of the step surface is 2 mm to 10 mm larger than the diameter of the pole piece 600, so that a position for placing the first welding ring 110 can be reserved, which reduces the difficulty of assembly and makes it easier to weld the first welding ring 110 to the first current collecting plate 100.

[0051] In some embodiments, reference Figure 4 , the plastic part 400 is provided with a limiting block 440, the insulating part 200 is provided with a first positioning hole 200a, the second welding ring 310 is provided with a second positioning hole 310a, and the limiting block 440 extends in a direction close to the wound electrode assembly 500 and penetrates the second positioning hole 310a and the first positioning hole 200a in sequence. Specifically, the assembly sequence is: the insulating part 200 is placed on the first current collecting plate 100, and then the second welding ring 310 is placed on the plate part 210, and the second positioning hole 310a is aligned with the first positioning hole 200a, and then the plastic part 400 is placed on the plate part 210, and the limiting block 440 is aligned with the second positioning hole 310a, and finally the first welding ring 110 and the end cover 300 are arranged in sequence. By providing a limit block 440 on the plastic part 400, providing a first positioning hole 200a on the insulating part 200, and providing a second positioning hole 310a on the second welding ring 310, the second welding ring 310 can be positioned more accurately during assembly to prevent the second welding ring 310 from deviating from the assembly position before welding with the end cover 300.

[0052] In some embodiments, the number of the sinking grooves 120 is 8, which can not only improve the reliability of the welding between the first current collecting plate 100 and the tab, but also allow the first current collecting plate 100 to have sufficient current flow capacity to ensure that the energy storage device has good performance. In other embodiments, the number of the sinking grooves 120 can also be 10 or 12, etc., which is not specifically limited here.

[0053] In some embodiments, reference Figures 1 to 4 The energy storage device further includes a shell 700 and a positive electrode column 610. An opening is formed at one end of the shell 700. The end cover 300 is covered on the shell 700 and closes the opening. The positive electrode column 610 is connected to the first current collecting disk 100. Specifically, the shell 700 is cylindrical and can accommodate the wound electrode assembly 500. The shell 700 is provided with an opening to facilitate the placement of the wound electrode assembly 500. The end cover 300 closes the opening to prevent the wound electrode assembly 500 from falling out. In actual production, the end cover 300 can be fixedly connected to the shell 700 by welding. The positive electrode column 610 passes through the first welding ring 110 and is welded to the first current collecting disk 100 to extract current. The above-mentioned energy storage device can extract current from the positive electrode while maintaining good insulation between the first current collecting disk 100 and the end cover 300.

[0054] In some embodiments, reference Figure 1 , a second current collecting disc 800 is provided in the housing 700, and the second current collecting disc 800 is located at one end of the wound electrode assembly 500 away from the first current collecting disc 100, so as to draw current from the negative electrode of the energy storage device. The second current collecting disc 800 is provided with a second step portion (not shown in the figure), and the second step portion protrudes in a direction away from the wound electrode assembly 500, and the negative electrode pole 620 is welded to the second step portion to draw current from the wound electrode assembly 500 through the second current collecting disc 800. A through hole (not shown in the figure) is provided at one end of the housing 700 away from the opening, specifically, the diameter of the second step portion is 2 mm to 10 mm larger than the diameter of the negative electrode pole 620, and the diameter of the through hole is 0.5 mm to 1 mm larger than the diameter of the negative electrode pole 620. In this way, during the production process of the energy storage device, when the shelling process is carried out, that is, when the wound electrode assembly 500 is placed in the outer shell 700, a certain deviation between the wound electrode assembly 500 and the outer shell 700 can be allowed, thereby improving the assembly efficiency and yield of the wound electrode assembly 500 into the shell.

[0055] In some embodiments, the first current collecting disc 100 is a single-layer structure. The conventional current collecting disc has a multi-layer structure. During the assembly of the energy storage device, the current collecting disc protrudes from the end of the shell. The end cap 300 needs to be pressed into the shell to fold the current collecting disc so as to be in close contact with the wound electrode assembly 500 and give full play to the flow-through effect. However, even after folding, the current collecting disc with a multi-layer structure occupies more space in the shell, resulting in a reduction in the energy density of the energy storage device. Moreover, the end cap 300 and the shell are easily misaligned and aluminum wires are scratched, resulting in a short circuit in the energy storage device and a risk of fire. The first current collecting disc 100 in the present application is a single-layer structure, does not need to be folded, occupies a small space, and can improve the energy density of the energy storage device; moreover, when installing the end cap 300, it is not necessary to fold the first current collecting disc 100 and the pole ear, which reduces the amount of aluminum wires scratched and reduces the risk of short circuit in the energy storage device. The end cap 300 is overlapped with the housing 700, the side of the end cap 300 is laser-penetrated and welded to the housing 700, and the top of the end cap 300 is seam-welded to the housing 700. In this way, even the first current collecting plate 100 with a single-layer structure can have a good fixing effect.

[0056] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. An energy storage device, characterized in that: include: A wound electrode assembly for storing electricity; A first current collecting disk, covering one end of the wound electrode assembly, wherein a first welding ring is provided on a side of the first current collecting disk away from the wound electrode assembly; A pole ear connected to the first current collecting plate, and the pole ear is used to draw out current; an insulating member, disposed on a side of the first current collecting disk away from the wound electrode assembly, at least a portion of the insulating member being spaced apart from the first current collecting disk; an end cap, arranged on a side of the insulating member away from the wound electrode assembly, wherein a second welding ring is arranged between the end cap and the insulating member; A plastic part, at least part of which is sandwiched between the first welding ring and the second welding ring, and the plastic part is provided with a barb portion, which abuts against a portion where the insulating part and the first current collecting disk are spaced apart, and the barb portion is used to prevent the insulating part from moving in a direction close to the wound electrode assembly.

2. The energy storage device according to claim 1, characterized in that: The end cover is provided with a protruding portion, and the plastic part is provided with an extending portion, the extending portion corresponds to the protruding portion, and at least a portion of the extending portion is located between the inner wall of the protruding portion and the first welding ring.

3. The energy storage device according to claim 1 or 2, characterized in that: The insulating member includes a plate portion and a ridge portion connected to the plate portion, wherein the ridge portion contacts a side of the first current collecting disk away from the wound electrode assembly, so that the plate portion is spaced apart from the first current collecting disk.

4. The energy storage device according to claim 1 or 2, characterized in that: The first current collecting disk is provided with a welding area and a disk surface area. The first current collecting disk is formed with a sinking portion recessed toward the direction of the wound electrode assembly in the welding area. The electrode tab is connected to a side of the sinking portion away from the wound electrode assembly.

5. The energy storage device according to claim 1 or 2, characterized in that: The first current collecting disk is provided with a first step portion, the first step portion protrudes in a direction away from the wound electrode assembly, the first welding ring is connected to the first step portion, and the first step portion is also used for welding the pole piece.

6. The energy storage device according to claim 5, characterized in that: The end surface of the first step portion is circular, and the diameter of the first step portion is 2 mm to 10 mm larger than the diameter of the pole piece.

7. The energy storage device according to claim 1 or 2, characterized in that: The plastic part is provided with a limiting block, the insulating part is provided with a first positioning hole, the second welding ring is provided with a second positioning hole, and the limiting block extends toward the direction approaching the wound electrode assembly and penetrates into the second positioning hole and the first positioning hole in sequence.

8. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a shell and a positive electrode column. An opening is formed at one end of the shell. The end cover is disposed on the shell and closes the opening. The positive electrode column is connected to the first current collecting plate.

9. The energy storage device according to claim 8, characterized in that: The energy storage device also includes a second current collecting disk and a negative electrode pole, the second current collecting disk is arranged at one end of the wound electrode assembly away from the first current collecting disk, the second current collecting disk is provided with a second step portion, the second step portion protrudes in a direction away from the wound electrode assembly, the negative electrode pole is connected to the second step portion, the diameter of the second step portion is 2mm~10mm larger than the diameter of the negative electrode pole, and a through hole is provided at one end of the shell away from the opening, and the diameter of the through hole is 0.5mm~1mm larger than the diameter of the negative electrode pole.

10. The energy storage device according to claim 8 or 9, characterized in that: The first current collecting plate is a single-layer structure.

Images