CN116581489B

CN116581489B - End cover assembly, energy storage device and energy storage system

Info

Publication number: CN116581489B
Application number: CN202310851850.1A
Authority: CN
Inventors: 李茂松; 檀基本
Original assignee: Shenzhen Haichen Energy Storage Control Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Current assignee: Shenzhen Haichen Energy Storage Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Priority date: 2023-07-12
Filing date: 2023-07-12
Publication date: 2024-04-30
Anticipated expiration: 2043-07-12
Also published as: CN116581489A

Abstract

The application provides an end cover assembly, an energy storage device and an energy storage system. Comprises a first lower plastic, a first pole and a first adapter; the first lower plastic comprises a first surface facing the electrode assembly; the first pole is arranged in the first lower plastic in a penetrating way; the first transfer piece is in butt joint with the first surface and comprises a first pole welding part and first inner, middle and outer welding rings arranged on the first pole welding part; the central lines of the first inner, middle and outer welding rings are overlapped, the first inner, middle and outer welding rings are sequentially arranged and are arranged at intervals, and the first pole welding part is electrically connected with the first pole through the first inner, middle and outer welding rings; the first inner welding ring is provided with a first welding stress point, the first middle welding ring is provided with a second welding stress point, the first outer welding ring is provided with a third welding stress point, and any two welding stress points among the first welding stress point, the second welding stress point and the third welding stress point are arranged in a staggered mode. The technical scheme of the application can avoid the failure of the secondary battery caused by poor electrical connection performance between the pole and the electrode assembly.

Description

End cover assembly, energy storage device and energy storage system

Technical Field

The application relates to the field of energy storage, in particular to an end cover assembly, an energy storage device and an energy storage system.

Background

With the development of clean energy, more and more devices use energy storage devices such as secondary batteries as main energy sources. In the energy storage device, an adaptor is required to be arranged between the pole and the electrode assembly to realize the electrical connection between the pole and the electrode assembly. At present, the electrical connection performance between the polar post and the electrode assembly is poor, and the secondary battery is easy to lose efficacy in the use process, so that the service life of the battery is influenced.

Disclosure of Invention

The embodiment of the application provides an end cover assembly, an energy storage device and an energy storage system, which can avoid the problem that the service life of a secondary battery is influenced due to the fact that the secondary battery is invalid because of poor electric connection performance between a pole and an electrode assembly.

In a first aspect, the present application provides an end cap assembly comprising:

A first lower plastic comprising a first surface facing the electrode assembly;

the first pole is penetrated through the first lower plastic;

The first transfer piece is in butt joint with the first surface and can be electrically connected between the first pole and the electrode assembly, and the first transfer piece comprises a first pole welding part, a first inner welding ring, a first middle welding ring and a first outer welding ring which are arranged on the first pole welding part;

The central line of the first inner welding ring, the central line of the first middle welding ring and the central line of the first outer welding ring are overlapped, the first middle welding ring is positioned at the periphery of the first inner welding ring and is arranged at intervals with the first inner welding ring, the first outer welding ring is positioned at the periphery of the first middle welding ring and is arranged at intervals with the first middle welding ring, and the first pole welding part is electrically connected with the first pole through the first inner welding ring, the first middle welding ring and the first outer welding ring;

the first inner welding ring is provided with a first welding stress point, the first middle welding ring is provided with a second welding stress point, the first outer welding ring is provided with a third welding stress point, and any two welding stress points among the first welding stress point, the second welding stress point and the third welding stress point are arranged in a staggered mode along the radial direction of the first outer welding ring.

It is understood that the first weld stress point may identify a weld start point (end point) of the first inner weld ring, which may be a dimple formed by the first joint member that melts when heated. The second weld stress point may identify a weld start point (end point) of the first intermediate weld ring, which may be a dimple formed by the first joint member melted by heat. The third weld stress point may identify a weld start point (end point) of the first outer weld ring, which may be a dimple formed by the first joint member melted by heat. By arranging the welding starting points (end points) of the three welding rings in a staggered manner in the radial direction of the welding rings, the problem that the structural strength of the first adapter is insufficient due to melting of the first adapter when the welding starting points (end points) are concentrated in the same radial direction of the welding rings can be avoided. The first adapter piece can be effectively prevented from warping due to stress concentration, so that the first pole column and the electrode assembly have good electric connection performance, and the service life and the working reliability of the energy storage device applying the end cover assembly are improved.

In a possible embodiment, the spacing between the first inner and the first middle weld ring is smaller than the spacing between the first middle weld ring and the first outer weld ring.

It is understood that the first inner welding ring and the first middle welding ring are mainly used as current path areas between the first pole and the first transfer piece, and the surface connection structure is easy to form by arranging the space between the first inner welding ring and the first middle welding ring smaller, so that parasitic capacitance is avoided between the first inner welding ring and the first middle welding ring, and current loss is caused. The first outer welding ring is mainly used as a reinforcing ring for connecting the first pole with the first transfer piece, and the first outer welding ring has a larger ring diameter, so that the welding area of the first transfer piece and the first pole can be increased, and the structural strength of the end cover assembly is further improved. Through the cooperation of first interior welding circle, first well welding circle and first outer welding circle, can make the connection structure that forms the large tracts of land firm between first adaptor and the first utmost point post.

In a possible implementation manner, the first pole comprises a first column body and a first flange part, the first column body is convexly arranged on the first flange part, the first lower plastic is provided with a first pole through hole, the first pole through hole comprises a first hole and a second hole which are communicated, the aperture size of the second hole is larger than that of the first hole, part of the first column body is positioned in the first hole, the first flange part is positioned in the second hole, the surface of the first flange part deviating from the first column body is flush with the first surface, and the first flange part is fixedly connected with the first adapter through the first inner welding ring, the first middle welding ring and the first outer welding ring.

Under this setting, can make the lower surface (i.e. the surface that first flange portion deviates from first cylinder) of first utmost point post and the lower surface (i.e. first surface) of first plastic down coplane, make first utmost point post can not set up for the lower surface protrusion of first plastic down, thereby can be when first transition piece and first utmost point post welding, the lower surface direct butt of first transition piece and first plastic down, thereby will carry out welded first utmost point ear welded position's height lifting to the upper limit value with first transition piece, for first utmost point ear buckling (buckling 90 degrees to the welding of horizontal direction and first transition piece from the vertical direction of reel core), provide bigger bending angle, avoid causing the fracture because of first utmost point ear bending angle is too little, the production yield of energy memory is promoted.

In a possible implementation manner, an area of the first outer welding ring enclosed on the first pole welding part is larger than an orthographic projection area of the first column body on the first pole welding part.

Therefore, the first outer welding ring not only can realize the connection of the first connecting piece and the first pole, but also can enable the first connecting piece to realize the performance of further compressing the first lower plastic, so that the first lower plastic is tightly abutted with the end cover, and the connection reliability of each part in the end cover assembly is improved. In addition, heat during welding of the first transfer piece and the first pole column can be prevented from being concentrated in the column part area of the first pole column, so that the first upper plastic is softened, and the problem that the first pole column falls to one side of the winding core is solved.

In a possible embodiment, the orthographic projection of the first cylinder on the first pole welding part covers the orthographic projections of the first inner welding ring and the first middle welding ring on the first pole welding part.

It is understood that the first inner welding ring and the first middle welding ring are mainly used as current path areas between the first pole and the first adapter, and by making the front projection of the first column body on the welding part of the first pole cover the front projection of the first inner welding ring and the first middle welding ring on the welding part of the first pole, the first adapter and the first pole can be electrically conducted only by welding the first inner welding ring and the first middle welding ring together the first adapter and the first flange part of the first pole, so that a large-area stable electrical connection can be formed between the first adapter and the first column body, and the overcurrent capacity between the first adapter and the first column body is improved.

In a possible implementation manner, the first adaptor further includes a first array of indentations, the first array of indentations is disposed on a surface of the first post welding portion facing away from the first lower plastic, and the first inner welding ring, the first middle welding ring and the first outer welding ring are all located in an area surrounded by the first array of indentations on the first post welding portion.

On the one hand, the first array indentation can play a role in positioning, so that the first pole welding part and the first pole are aligned fast in the process of welding the first adapter piece and the first pole, and the welding efficiency of the first adapter piece and the first pole is improved. On the other hand, the first array indentation can improve the surface roughness performance of the welding part of the first pole, so that the phenomenon that the welding laser head is damaged due to specular reflection on the smooth surface of the welding part of the first pole when the first pole and the first adapter are subjected to laser penetration welding is avoided, the laser can diffuse reflection on the surface of the welding part of the first pole to quickly absorb laser energy, and the welding efficiency of the first adapter and the first pole is further improved.

In a possible embodiment, the spacing between the outer edge of the first outer ring and the outer edge of the first array of indentations is greater than or equal to 2mm.

Under this setting, can guarantee to fully weld between first transfer piece and the first utmost point post, further improve the connection performance between first transfer piece and the first utmost point post.

In a possible embodiment, the area of the first array of indentations that is enclosed on the first pole welding part is larger than the orthographic projection of the first flange part on the first pole welding part.

It can be appreciated that the first array indentation can play a role in positioning, so that in the process of welding the first adapter piece with the first pole, the first pole welding part of the first adapter piece is aligned with the first flange part of the first pole, the welding efficiency of the first adapter piece and the first pole is improved, and the welding reliability of the first adapter piece and the first flange part of the first pole is ensured.

In a possible implementation manner, the first adapter further comprises two first tab welding parts, the two first tab welding parts are connected to the same side of the first pole welding part, and the two first tab welding parts are arranged at intervals in the width direction of the end cover assembly;

the first pole welding part and the two first pole lug welding parts enclose to form an opening, the first lower plastic comprises a first lower plastic body and a shunt part, the shunt part is arranged protruding from the first surface of the first lower plastic body, and part of the shunt part is positioned in the opening.

It can be understood that the first adapter can avoid the setting space of the split part by enabling the partial split part to be located in the opening formed by surrounding the two first tab welding parts and the first pole welding part, so that the liquid leakage performance of the split part is prevented from being influenced.

In one possible implementation manner, the first lower plastic further includes a first retaining wall, the first retaining wall is disposed around the periphery of the first lower plastic body along the circumferential direction of the first lower plastic body, the first retaining wall is disposed protruding from the first surface of the first lower plastic body, the first retaining wall and the first lower plastic body are combined to form a first cavity, and the first cavity can accommodate part of the first adapter.

Therefore, the first retaining wall can strengthen the structural strength of the first lower plastic along the length direction and the width direction of the end cover assembly.

In one possible embodiment, the width W1 of the first pole weld along the length of the end cap assembly satisfies the range: w1 is more than or equal to 24mm and less than or equal to 38mm.

It can be appreciated that the first adaptor is a metal piece, and its mechanical strength is bigger, through setting the width W1 of first utmost point post welded part at aforesaid scope, can satisfy the joint strength of first adaptor and first utmost point post, make the first adaptor can be inseparable with first utmost point post welding together to with the inseparable butt of first lower plastic at the lower surface of end cover, promote the holistic structural strength of end cover subassembly.

In one possible embodiment, along the width direction of the end cap assembly, the width W2 of the first tab welding portion satisfies the range: w2 is more than or equal to 14mm and less than or equal to 27mm.

It can be understood that through setting up two first utmost point ear welded parts on first adaptor, and make two first utmost point ear welded parts keep away from first utmost point post, and can make the part that corresponds two first utmost point ear welded parts in the first plastic closely support on the end cover when two first utmost point ear welded parts weld with two first utmost point ears, consolidate the linking property of the part that first utmost point post was kept away from with first plastic, avoid the middle part of first plastic unsettled and appear plastic rotten after long-term work, the decline that the intensity decline leads to, and avoid because of the explosion-proof valve below opening increase behind the first plastic decline, the foreign matter gets into and is attached to the explosion-proof valve more easily, influence the valve opening performance of explosion-proof valve.

In one possible embodiment, along the length direction of the end cover assembly, the spacing W3 between the first pole welding portion and the split portion satisfies the range: w3 is more than or equal to 0.5mm and less than or equal to 2.5mm.

It can be understood that the interval between the first pole welding part and the split-flow part is set in the range, so that the first pole welding part and the split-flow part can keep proper interval, and the split-flow part has better structural strength, so that when electrolyte is injected into the split-flow part from the liquid injection hole at a high speed, the split-flow part is not easy to be impacted by strong liquid flow to cause downward bending and inclination, and the electrolyte is prevented from being sprayed out from the explosion-proof valve side in a large amount, and the distribution uniformity of the electrolyte is influenced.

In a second aspect, the present application also provides an energy storage device comprising an electrode assembly and an end cap assembly as described above, the electrode assembly being electrically connected to the end cap assembly.

In a third aspect, the present application also provides an energy storage system comprising an energy storage device as described above.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained by those skilled in the art without the inventive effort.

FIG. 1 is a schematic diagram of an energy storage system according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an energy storage device according to an embodiment of the present application;

FIG. 3 is an exploded schematic view of the energy storage device shown in FIG. 2;

FIG. 4 is a schematic view of a structure of an expanded state of an electrode assembly of the energy storage device shown in FIG. 2;

FIG. 5 is a schematic view of a portion of the energy storage device shown in FIG. 2;

FIG. 6 is a schematic structural view of an end cap assembly of the energy storage device shown in FIG. 2;

FIG. 7 is an exploded schematic view of the end cap assembly of FIG. 6;

FIG. 8 is a schematic view of an angle of the lower plastic component of the end cap assembly of FIG. 7;

FIG. 9 is a schematic cross-sectional view taken along section line A-A shown in FIG. 6;

FIG. 10 is a schematic view illustrating an angle of assembly of the lower plastic component and the adapter component shown in FIG. 7;

FIG. 11 is a schematic view of an angle of the first adapter of the adapter assembly of FIG. 7;

FIG. 12 is a schematic view of another angle configuration of the first adapter of the adapter assembly of FIG. 7;

FIG. 13 is a schematic view illustrating an angle of assembly of the first adapter and the first lower plastic in FIG. 7;

FIG. 14 is a schematic view of the construction of weld stress points on the first adapter or the second adapter of the end cap assembly shown in FIG. 6;

FIG. 15 is a schematic view of an angled construction of a second adapter of the adapter assembly of FIG. 7;

FIG. 16 is a schematic view of another angle of a second adapter of the adapter assembly of FIG. 7;

FIG. 17 is a schematic view illustrating an angle of assembly of the second adapter shown in FIG. 7 with the second lower plastic.

Reference numerals:

Energy storage system 300, photovoltaic panel 310, fan 320, grid 330, energy storage device 200, housing 210, end cap assembly 100, electrode assembly 220, protective film 230, pole core connection C, pole core 2210, pole core 2220, first pole ear 2230, second pole ear 2240, explosion-proof valve assembly 10, end cap 20, lower plastic assembly 30, pole column assembly 40, upper plastic assembly 50, adapter assembly 60, insulating film assembly 70, liquid injection hole seal 80, explosion-proof valve 11, protective sheet 12, third pole through-hole 21, fourth pole through-hole 22, liquid injection hole 23, explosion-proof valve through-hole 24, first lower plastic 31, second lower plastic 32, first lower plastic body 311, first protrusion 312, shunt 313, first retaining wall 314, first surface 3111, second surface 3112, first pole through-hole 315, first hole 3151, second hole 3152, liquid leakage hole 3131, first cavity 316, second lower plastic body 321, second protrusion 322, second retaining wall 323 the explosion proof valve barrier 324, the third surface 3211, the fourth surface 3212, the second post through hole 325, the third hole 3251, the fourth hole 3252, the second cavity 326, the first post 41, the second post 42, the first seal 43, the second seal 44, the first post 411, the first flange 412, the second post 421, the second flange 422, the first upper plastic 51, the second upper plastic 52, the first adapter 61, the second adapter 62, the first post weld 611, the first tab weld 612, the first inner weld 613, the first middle weld 614, the first outer weld 615, the first array indentation 616, the opening 617, the width W1 of the first post weld 611, the width W2 of the first tab weld 612, the spacing W3 between the first post weld 611 and the shunt 313, the spacing D1 between the first inner weld 613 and the first middle weld 614, the spacing D2 between the first middle weld 614 and the first outer weld 615, the first welding stress point 6131, the second welding stress point 6141, the third welding stress point 6151, the second pillar welding portion 621, the second pillar welding portion 622, the second inner bead 623, the second middle bead 624, the second outer bead 625, the second array indentation 626, the width W4 of the second pillar welding portion 621, the width W5 of the second pillar welding portion 622, the distance D3 between the second inner bead 623 and the second middle bead 624, the distance D4 between the second middle bead 624 and the second outer bead 625, the fourth welding stress point 6231, the fifth welding stress point 6241, the sixth welding stress point 6251, the first insulating film 71, the second insulating film 72, the third insulating film 73, the fourth insulating film 74, the fifth insulating film 75, and the sixth insulating film 76.

Detailed Description

For convenience of understanding, terms involved in the embodiments of the present application will be explained first.

And/or: merely one association relationship describing the associated object, the representation may have three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone.

A plurality of: refers to two or more.

And (3) connection: it is to be understood in a broad sense that, for example, a is linked to B either directly or indirectly via an intermediary.

The following description of the embodiments of the present application will be made with reference to the accompanying drawings.

Because of the strong timeliness and space properties of energy required by people, in order to reasonably utilize the energy and improve the utilization rate of the energy, one energy form needs to be stored by one medium or equipment and then converted into another energy form, and the energy is released in a specific energy form based on future application. It is well known that the main way to generate green electric energy is to develop green energy sources such as photovoltaic, wind power and the like to replace fossil energy sources. At present, the generation of green electric energy generally depends on photovoltaic, wind power, water potential and the like, but wind energy, solar energy and the like generally have the problems of strong intermittence and large fluctuation, which can cause unstable power grid, insufficient peak electricity consumption, too much electricity consumption and unstable voltage can cause damage to the electric power, so that the problem of 'wind abandoning and light abandoning' possibly occurs due to insufficient electricity consumption requirement or insufficient power grid acceptance, and the problem needs to be solved by relying on energy storage. The energy is converted into other forms of energy through physical or chemical means and is stored, the energy is converted into electric energy when needed and released, in short, the energy storage is similar to a large-scale 'charge pal', the electric energy is stored when the photovoltaic and wind energy are sufficient, and the stored electric power is released when needed.

Taking electrochemical energy storage as an example, the scheme provides an energy storage device, wherein a group of chemical batteries are arranged in the energy storage device, chemical elements in the chemical batteries are mainly used as energy storage media, and the charge and discharge process is accompanied with chemical reaction or change of the energy storage media.

The existing energy storage (i.e. energy storage) application scene is wider, including aspects such as (wind and light) power generation side energy storage, electric network side energy storage, base station side energy storage and user side energy storage, the types of corresponding energy storage devices include:

(1) The large energy storage container applied to the energy storage scene at the power grid side can be used as a high-quality active and reactive power regulation power supply in the power grid, so that the load matching of electric energy in time and space is realized, the renewable energy consumption capability is enhanced, and the large energy storage container has great significance in the aspects of standby of a power grid system, relieving peak load power supply pressure and peak regulation and frequency modulation.

(2) The small and medium energy storage electric cabinet is applied to industrial and commercial energy storage scenes (banks, markets and the like) at the user side, and the main operation mode is peak clipping and valley filling. Because of the large price difference of the electricity charge at the peak-valley position according to the electricity consumption requirement, after the energy storage equipment is arranged by a user, in order to reduce the cost, the energy storage cabinet/box is charged usually in the electricity price valley period; and in the peak period of electricity price, the electricity in the energy storage equipment is released for use, so that the purpose of saving electricity charge is achieved.

Referring to fig. 1, fig. 1 is a schematic diagram of an energy storage system 300 according to an embodiment of the application.

The embodiment of the application provides an energy storage system 300, wherein the energy storage system 300 comprises an electric energy conversion device (a photovoltaic panel 310), a wind energy conversion device (a fan 320), a power grid 330 and an energy storage device 200, and the energy storage device 200 can be used as an energy storage cabinet and can be installed outdoors. In particular, the photovoltaic panel 310 may convert solar energy into electrical energy during low electricity price periods, and the energy storage device 200 is used to store the electrical energy and supply the electrical grid 330 during peak electricity use or to supply power during power outage/interruption of the electrical grid 330. Wind energy conversion device (wind turbine 320) may convert wind energy into electrical energy, and energy storage device 200 may be used to store the electrical energy and supply electrical grid 330 during peak power usage or to provide power during a power outage/outage of electrical grid 330. The transmission of the electric energy can be performed by adopting a high-voltage cable.

The number of the energy storage devices 200 may be several, and the several energy storage devices 200 are connected in series or parallel, and the several energy storage devices 200 are supported and electrically connected by using a separator (not shown). In this embodiment, "a plurality of" means two or more. The energy storage device 200 may further be provided with an energy storage box outside for accommodating the energy storage device 200.

It is understood that the energy storage device 200 may include, but is not limited to, a battery cell, a battery module, a battery pack, a battery system, etc. The practical application form of the energy storage device provided in the embodiment of the present application may be, but not limited to, the listed products, and may be other application forms, and the embodiment of the present application does not strictly limit the application form of the energy storage device 200. The embodiment of the present application will be described by taking the energy storage device 200 as a multi-core battery.

Referring to fig. 2, 3 and 4 in combination, fig. 2 is a schematic structural diagram of an energy storage device 200 according to an embodiment of the application, fig. 3 is an exploded schematic diagram of the energy storage device 200 shown in fig. 2, and fig. 4 is a schematic structural diagram of an expanded state of an electrode assembly 220 of the energy storage device 200 shown in fig. 2.

The energy storage device 200 may include a case 210, an end cap assembly 100, an electrode assembly 220, and a protective film 230. An opening is provided at one end of the case 210, the electrode assembly 220 is mounted inside the case 210, and the cap assembly 100 is connected to the opening of the case 210 and encapsulates the electrode assembly 220 in cooperation with the case 210. The end cap assembly 100 is electrically connected to the electrode assembly 220 to achieve extraction of the battery electrodes. The protection film 230 may fix the junction of the electrode assembly 220 and the cap assembly 100 to ensure the stability and reliability of the electrical connection performance of the electrode assembly 220 and the cap assembly 100. Illustratively, the housing 210 is a metal housing, such as an aluminum housing. Of course, the housing 210 may be made of other materials. The protective film 230 may be an insulating tape such as a blue film.

It should be noted that fig. 2 to 4 are only for schematically describing the connection relationship of the case 210, the end cap assembly 100, the electrode assembly 220, and the protection film 230, and are not intended to limit the connection positions, specific configurations, and the number of the respective devices. The illustrated structure of the embodiment of the present application does not constitute a specific limitation on the energy storage device 200. In other embodiments of the present application, the energy storage device 200 may include more or fewer components than those shown in fig. 2-4, or may combine certain components, or split certain components, or may have a different arrangement of components. The components shown in fig. 2-4 may be implemented in hardware, software, or a combination of software and hardware.

Referring to fig. 3, fig. 4, and fig. 5 in combination, fig. 5 is a schematic diagram of a portion of the energy storage device 200 shown in fig. 2.

The end cap assembly 100 includes at least two pole core connection parts C disposed in sequence in a thickness direction thereof. The electrode assembly 220 may include at least two electrode cores 2210, and the at least two electrode cores 2210 are sequentially arranged in a thickness direction of the electrode assembly 220. The number of pole cores 2210 may be the same as the number of pole core connections C, each pole core 2210 being connected with one pole core connection C of the end cap assembly 100. By arranging the plurality of pole cores 2210 in the energy storage device 200, the battery capacity of the energy storage device 200 can be increased, so that the battery can be used for a long time, and the application scene of the battery is further increased.

For example, the end cap assembly 100 may include two pole core connection portions C, which may be symmetrically disposed. The electrode assembly 220 may include two electrode cores 2210. One pole core 2210 is connected to one pole core connection part C, and the other pole core 2210 is connected to the other pole core connection part C, thereby electrically connecting the end cap assembly 100 with the electrode assembly 220.

Each of the pole cores 2210 may include a winding core 2220, a first pole tab 2230, and a second pole tab 2240, the first pole tab 2230 and the second pole tab 2240 being connected to the winding core 2220. The polarities of the first tab 2230 and the second tab 2240 are opposite, one being a positive tab and the other being a negative tab.

The winding core 2220 may include a positive electrode sheet (not shown), a negative electrode sheet (not shown), and a separator (not shown), the separator being interposed between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet being electrically connected with the first tab 2230, the negative electrode sheet being electrically connected with the second tab 2240. The positive electrode sheet, the separator and the negative electrode sheet are sequentially laminated to form a laminated structure, the laminated structure is wound to form a winding core 2220, a portion of the positive electrode sheet extending out of the winding core 2220 can form a first tab 2230, and a portion of the negative electrode sheet extending out of the winding core 2220 can form a second tab 2240. The diaphragm can be a base film prepared from an insulating material, has lighter weight and good tensile property, and can be well connected with the positive pole piece and the negative pole piece. Illustratively, the material of the separator may be a polymeric insulating layer, such as: films of polystyrene, polypropylene, polyester, polycarbonate, polytetrafluoroethylene, polyimide, and the like; the material of the separator may be synthetic fiber insulating paper, for example: aromatic polyamide fiber paper and polyester fiber paper; the material of the separator may be various insulating tapes or the like.

In a specific application scenario, as shown in fig. 3 and 4, the number of pole cores 2210 is two, and the number of protective films 230 is four. When the two pole cores 2210 are installed inside the housing 210, the first pole lug 2230 of one pole core 2210 is opposite to the first pole lug 2230 of the other pole core 2210 along the thickness direction of the energy storage device 200, and the second pole lug 2240 of one pole core 2210 is opposite to the second pole lug 2240 of the other pole core 2210, so that the extraction of the same polarity electrode of the two pole cores 2210 can be realized. The number of the protection films 230 is the same as that of the tabs, and each protection film 230 can be attached to the connection part of one tab (the first tab 2230 and the second tab 2240) and the end cover assembly 100, so as to realize the functions of fixing, insulating protection and the like of one tab.

Referring to fig. 6 and 7 in combination, fig. 6 is a schematic structural view of the end cap assembly 100 of the energy storage device 200 shown in fig. 2, and fig. 7 is an exploded schematic view of the end cap assembly 100 shown in fig. 6.

The end cap assembly 100 may include an explosion protection valve assembly 10, an end cap 20, a lower plastic assembly 30, a pole assembly 40, an upper plastic assembly 50, an adapter assembly 60, an insulating film assembly 70, and a fill hole seal 80. The adapter assembly 60 is connected to the electrode assembly 220. The lower plastic component 30 is located on the side of the adapter component 60 facing away from the electrode component 220. The end cap 20 is located on a side of the lower plastic component 30 facing away from the adapter component 60, and the end cap 20 is stacked with the lower plastic component 30. The pole assembly 40 passes through the end cover 20 and the lower plastic assembly 30, one end of the pole assembly 40 extends out of the lower plastic assembly 30 to be connected with the switching assembly 60, and the other end of the pole assembly 40 extends out of the end cover 20 to be led out as an electrode of the energy storage device 200. The upper plastic component 50 is sleeved on the pole component 40. The explosion protection valve assembly 10 is mounted to the end cap 20 and is used for pressure relief protection of the energy storage device 200. The insulation film assembly 70 is connected between the relay assembly 60 and the electrode assembly 220 and between the relay assembly 60 and the lower plastic assembly 30 for protecting the respective welding points on the relay assembly 60. A fill port seal 80 is connected to the end cap 20 and is used to seal the fill port 23 in the end cap 20.

The explosion proof valve assembly 10 may include an explosion proof valve 11 and a protective sheet 12, the protective sheet 12 being stacked with the explosion proof valve 11, the protective sheet 12 covering the explosion proof valve 11.

The end cap 20 is provided with a third pole through hole 21, a fourth pole through hole 22, a liquid injection hole 23 and an explosion-proof valve through hole 24. The third pole through hole 21 and the fourth pole through hole 22 are provided at opposite ends of the end cover 20 in the length direction, the third pole through hole 21 is used for allowing the first pole 41 to pass through, and the fourth pole through hole 22 is used for allowing the second pole 42 to pass through. The liquid injection hole 23 is located between the third pole through hole 21 and the fourth pole through hole 22, and the liquid injection hole 23 is used to provide a liquid passage to inject an external electrolyte into the inside of the energy storage device 200. An explosion proof valve through hole 24 is located between the liquid injection hole 23 and the fourth pole through hole 22, and the explosion proof valve through hole 24 is used for installing the explosion proof valve assembly 10. Along the length direction of the end cap 20, a third pole through hole 21, a liquid injection hole 23, an explosion-proof valve through hole 24 and a second pole through hole 325 are sequentially provided.

Referring to fig. 7 and 8 in combination, fig. 8 is a schematic view of an angle of the lower plastic component 30 of the end cap assembly 100 shown in fig. 7. The lower plastic component 30 is laminated with the end cap 20, and the lower plastic component 30 includes a first lower plastic 31 and a second lower plastic 32. The first lower plastic 31 and the second lower plastic 32 are arranged along the length direction of the energy storage device 200. The length of the first lower plastic 31 is less than the length of the second lower plastic 32 along the length of the end cap assembly 100.

The first lower plastic 31 includes a first lower plastic body 311, a first protrusion 312, a diversion portion 313 and a first retaining wall 314.

The first lower plastic body 311 includes a first surface 3111 and a second surface 3112 disposed opposite to each other, the first surface 3111 is a surface of the first lower plastic body 311 facing the adapter assembly 60, and the second surface 3112 is a surface of the first lower plastic body 311 facing the end cap 20.

The first protrusion 312 is disposed on the second surface 3112 of the first lower plastic body 311, and the first protrusion 312 is disposed protruding with respect to the second surface 3112 of the first lower plastic body 311.

The first lower plastic 31 is provided with a first post through hole 315, the first post through hole 315 is located on the first lower plastic body 311 and the first protrusion 312, the first post through hole 315 penetrates through the first lower plastic body 311 and the first protrusion 312 along the thickness direction of the end cover assembly 100, and the first post through hole 315 is used for allowing the first post 41 to pass through. The first pole through hole 315 is disposed opposite to the third pole through hole 21 of the end cap 20 in the thickness direction of the end cap assembly 100. The first post through hole 315 includes a first hole 3151 and a second hole 3152 that are in communication, the second hole 3152 having a larger aperture size than the first hole 3151. Illustratively, the first aperture 3151 may be in the shape of a circular aperture and the second aperture 3152 may be in the shape of a square aperture.

The split portion 313 is concavely disposed relative to the second surface 3112 of the first lower plastic body 311 and convexly disposed relative to the first surface 3111 of the first lower plastic body 311, the split portion 313 is disposed opposite to the liquid injection hole 23 of the end cap 20 in the thickness direction of the end cap assembly 100, and the split portion 313 is in communication with the liquid injection hole 23. The diverting portion 313 may have a plurality of weeping holes 3131, the plurality of weeping holes 3131 being arranged at intervals along the circumferential direction of the diverting portion 313, each weeping hole 3131 being a through hole. With this arrangement, after the electrolyte is injected from the injection hole 23 of the end cap 20, the electrolyte can flow into the shunt portion 313 and flow out from the plurality of drain holes 3131 of the shunt portion 313 to the electrode assembly 220. And the arrangement of the plurality of weeping holes 3131 can make the flow of the electrolyte more uniform.

The first retaining wall 314 is disposed on the first surface 3111 of the first lower plastic body 311, the first retaining wall 314 protrudes from the first surface 3111 of the first lower plastic body 311, the first retaining wall 314 is disposed around the periphery of the first lower plastic body 311 along the circumferential direction of the first lower plastic body 311, and the first retaining wall 314 can strengthen the structural strength of the first lower plastic 31 along the length direction and the width direction of the end cover assembly 100. The first retaining wall 314 may be configured to enclose with the first lower plastic body 311 to form a first cavity 316, and the first cavity 316 may house a portion of the first adapter 61.

The second lower plastic 32 includes a second lower plastic body 321, a second protrusion 322, a second retaining wall 323, and an explosion-proof valve fence 324.

The second lower plastic body 321 includes a third surface 3211 and a fourth surface 3212 disposed opposite to each other, the third surface 3211 is a surface of the second lower plastic body 321 facing the adapter component 60, and the fourth surface 3212 is a surface of the second lower plastic body 321 facing the end cover 20.

The second protrusion 322 is disposed on the fourth surface 3212 of the second lower plastic body 321, and the second protrusion 322 is disposed protruding with respect to the fourth surface 3212 of the second lower plastic body 321.

The second lower plastic 32 is provided with a second post through hole 325, the second post through hole 325 is located on the second lower plastic body 321 and the second protrusion 322, the second post through hole 325 penetrates through the second lower plastic body 321 and the second protrusion 322 along the thickness direction of the end cover assembly 100, and the second post through hole 325 is used for passing through the second post 42. The second post through-holes 325 are disposed opposite to the fourth post through-holes 22 of the end cap 20 in the thickness direction of the end cap assembly 100. The second post via 325 includes a third hole 3251 and a fourth hole 3252 in communication, the fourth hole 3252 having a larger aperture size than the third hole 3251. Illustratively, the third hole 3251 may be in the shape of a circular hole and the fourth hole 3252 may be in the shape of a square hole.

The explosion-proof valve fence 324 is concavely disposed with respect to the fourth surface 3212 of the second lower plastic body 321 and convexly disposed with respect to the third surface 3211 of the second lower plastic body 321.

The second retaining wall 323 is disposed on the third surface 3211 of the second lower plastic body 321, the second retaining wall 323 is disposed protruding from the third surface 3211 of the second lower plastic body 321, the second retaining wall 323 is disposed around the second lower plastic body 321 along the circumferential direction, and the second retaining wall 323 can strengthen the structural strength of the second lower plastic 32 along the length direction and the width direction of the end cover assembly 100. The second retaining wall 323 can be formed with a second cavity 326 by being engaged with the second lower plastic body 321, and the second cavity 326 can accommodate a portion of the second adaptor 62.

Referring to fig. 7 and 9 in combination, fig. 9 is a schematic cross-sectional view taken along the section line A-A shown in fig. 6.

The post assembly 40 may include a first post 41, a second post 42, a first seal 43, and a second seal 44, wherein one of the first post 41 and the second post 42 is a positive post and the other is a negative post.

The first pole 41 is disposed through the end cap 20 and the first lower plastic 31, and the first pole 41 may include a first column 411 and a first flange 412. The first column 411 is protruding on the first flange 412, the cross-sectional width of the first column 411 along the height direction of the end cap assembly 100 is smaller than the cross-sectional width of the first flange 412 along the height direction of the end cap assembly 100, and the outer diameter of the first column 411 is smaller than the outer diameter of the first flange 412. A portion of the first column 411 is positioned within the first hole 3151, and another portion of the first column 411 protrudes from the end cap 20 and is disposed to protrude with respect to the end cap 20. The first flange portion 412 is positioned within the second bore 3152. The surface of the first flange portion 412 facing away from the first column 411 is flush with the first surface 3111 of the first lower plastic 31, so that under the arrangement, the lower surface of the first pole 41 (i.e., the surface of the first flange portion 412 facing away from the first column 411) and the lower surface of the first lower plastic 31 (i.e., the first surface 3111) are coplanar, so that the first pole 41 cannot be arranged to protrude relative to the lower surface of the first lower plastic 31, and therefore when the first adapter 61 is welded with the first pole 41, the first adapter 61 can directly abut against the lower surface of the first lower plastic 31, so that the height of the welding position of the first pole 2230, which is welded with the first adapter 61, is raised to an upper limit value, a larger bending angle is provided for bending the first pole 2230 (bending 90 degrees from the vertical direction of the winding core 2220 to the welding with the first adapter 61 in the horizontal direction), and breakage caused by excessively small bending angle of the first pole 2230 is avoided, and the production yield of the energy storage device 200 is improved.

The first sealing member 43 is annular, the first sealing member 43 is sleeved on the periphery of the first column 411 and contacts the first flange 412, and the first sealing member 43 elastically abuts between the first column 411 and the first hole 3151 of the first pole through hole 315.

The second post 42 is disposed through the end cap 20 and the second lower plastic 32, and the second post 42 may include a second post 421 and a second flange 422. The second post 421 is disposed on the second flange 422 in a protruding manner, and the cross-sectional width of the second post 421 along the height direction of the end cap assembly 100 is smaller than the cross-sectional width of the second flange 422 along the height direction of the end cap assembly 100, and the outer diameter of the second post 421 is smaller than the outer diameter of the second flange 422. A portion of the second cylinder 421 is located in the third hole 3251, and another portion of the second cylinder 421 protrudes from the end cap 20 and is disposed to protrude with respect to the end cap 20. The second flange portion 422 is positioned within the fourth aperture 3252. The surface of the second flange portion 422 facing away from the second post 421 is flush with the third surface 3211 of the second lower plastic 32, and under this arrangement, the lower surface of the second post 42 (i.e., the surface of the second flange portion 422 facing away from the second post 421) and the lower surface of the second lower plastic 32 (i.e., the third surface 3211) are coplanar, so that the second post 42 cannot be arranged to protrude relative to the lower surface of the second lower plastic 32, and therefore, when the second adaptor 62 is welded with the second post 42, the second adaptor 62 can directly abut against the lower surface of the second lower plastic 32, so that the height of the welding position of the second lug 2240 that can be welded with the second adaptor 62 is raised to an upper limit value, a larger bending angle is provided for bending the second lug 2240 (bending from the vertical direction of the winding core 2220 to the horizontal direction and welding with the second adaptor 62), and breakage caused by excessively small bending angle of the second lug 2240 is avoided, and the production yield of the energy storage device 200 is improved.

The second sealing member 44 is annular, the second sealing member 44 is sleeved on the periphery of the second post 421 and contacts the second flange 422, and the second sealing member 44 elastically abuts between the second post 421 and the third hole 3251 of the second post through hole 325.

With continued reference to fig. 7 and 9, the upper plastic component 50 may include a first upper plastic 51 and a second upper plastic 52.

The first upper plastic 51 is annular, the first upper plastic 51 is sleeved on the periphery of the first column 411 and contacts with the first sealing member 43, a part of the first upper plastic 51 is located in the first hole 3151 of the first pole through hole 315 and the first column 411, and the other part of the first upper plastic 51 is located outside the end cover 20 and protrudes relative to the end cover 20.

The second upper plastic 52 is annular, the second upper plastic 52 is sleeved on the periphery of the second post 421 and contacts the second sealing member 44, a part of the second upper plastic 52 is located in the third hole 3251 of the second post through hole 325 and the second post 421, and another part of the second upper plastic 52 is located outside the end cover 20 and protrudes relative to the end cover 20.

Referring to fig. 7 and 10 in combination, fig. 10 is a schematic view illustrating an angle of assembly of the lower plastic component 30 and the adapter component 60 shown in fig. 7.

The adapter assembly 60 may include a first adapter 61 and a second adapter 62. The first adaptor 61 is connected between the first tab 2230 and the first pole 41, and a portion of the first adaptor 61 is located in the first cavity 316 of the first lower plastic 31, and the first adaptor 61 can electrically connect the first tab 2230 and the first pole 41. The second adaptor 62 is connected between the second lug 2240 and the second post 42, and a portion of the second adaptor 62 is located in the second cavity 326 of the second lower plastic 32, and the second adaptor 62 can electrically connect the second lug 2240 and the second post 42.

Referring to fig. 7, 11, 12 and 13, fig. 11 is a schematic view illustrating an angle of the first adaptor 61 of the adaptor assembly 60 shown in fig. 7, fig. 12 is a schematic view illustrating another angle of the first adaptor 61 of the adaptor assembly 60 shown in fig. 7, and fig. 13 is a schematic view illustrating an angle of assembling the first adaptor 61 and the first lower plastic 31 shown in fig. 7.

The first adaptor 61 abuts against the first surface 3111 of the first lower plastic 31. The first adapter 61 may include a first tab weld 611, two first tab welds 612, a first inner weld 613, a first middle weld 614, a first outer weld 615, and a first array of indentations 616.

The first pole welding portion 611 is used for electrically connecting the first adapter 61 and the first pole 41. In one possible embodiment, the width W1 of the first pole weld 611 along the length of the end cap assembly 100 satisfies the range: w1 is more than or equal to 24mm and less than or equal to 38mm. It can be appreciated that the first adaptor 61 is a metal member, and has a greater mechanical strength, and by setting the width W1 of the first pole welding portion 611 within the foregoing range, the connection strength between the first adaptor 61 and the first pole 41 can be satisfied, so that the first adaptor 61 can be welded with the first pole 41 tightly, and the first lower plastic 31 can be abutted tightly against the lower surface of the end cover 20, thereby improving the overall structural strength of the end cover assembly 100.

The two first tab welding parts 612 are connected to the same side of the first tab welding part 611, and the two first tab welding parts 612 are spaced apart in the width direction of the end cap assembly 100, so that the shape of the first adapter 61 is C-shaped. Each first tab welding portion 612 is configured to connect with a first tab 2230 of one of the cores 2210.

In one possible embodiment, the width W2 of the first tab weld 612 along the width direction of the end cap assembly 100 satisfies the range: w2 is more than or equal to 14mm and less than or equal to 27mm. It can be understood that, by disposing the two first tab welding portions 612 on the first adapter 61 and making the two first tab welding portions 612 far away from the first pole 41, when the two first tab welding portions 612 are welded with the two first tabs 2230, the portions of the first lower plastic 31 corresponding to the two first tab welding portions 612 are tightly abutted against the end cover 20, so as to reinforce the connection performance of the end cover 20 and the portions of the first lower plastic 31 far away from the first pole 41, avoid sagging caused by plastic deterioration and strength degradation after long-term operation due to suspension of the middle portion of the first lower plastic 31, and avoid the increase of the opening below the explosion-proof valve 11 after the sagging of the first lower plastic 31, so that foreign matters are easier to enter and adhere to the explosion-proof valve 11, and affect the valve opening performance of the explosion-proof valve 11.

As shown in fig. 13, the two first tab welding portions 612 and the first tab welding portion 611 enclose an opening 617, and the partial shunt portion 313 is located in the opening 617. It can be appreciated that, by locating the partial shunt portion 313 in the opening 617 formed by the two first tab welding portions 612 and the first post welding portion 611, the first adapter 61 can be led out of the installation space of the shunt portion 313, so as to avoid affecting the leakage performance of the shunt portion 313.

In one possible embodiment, the spacing W3 between the first pole weld 611 and the shunt 313 along the length of the end cap assembly 100 satisfies the range 0.5mm < W3 < 2.5mm. It can be appreciated that, by setting the interval between the first pole welding portion 611 and the split portion 313 in the above-mentioned range, the first pole welding portion 611 and the split portion 313 can be kept at a proper interval, so that the split portion 313 has a better structural strength, and therefore, when the electrolyte is injected into the split portion 313 from the injection hole 23 at a high speed, the split portion 313 is not easy to be impacted by strong liquid flow to cause a downward bend and incline, so that a large amount of electrolyte is prevented from being ejected from the explosion-proof valve 11 side, and the uniformity of the electrolyte distribution is prevented from being affected.

Referring to fig. 11 and 12 in combination, a first array of indentations 616 is provided on a surface of the first post weld 611 facing away from the first lower plastic 31. Illustratively, the first array of indentations 616 may include a plurality of array-disposed spot indentations, with two adjacent spot indentations being spaced apart.

The first inner welding ring 613, the first middle welding ring 614 and the first outer welding ring 615 are all arranged on the first pole welding part 611, the first inner welding ring 613, the first middle welding ring 614 and the first outer welding ring 615 are all contacted with the first flange part 412 of the first pole 41, and the first flange part 412 is fixedly connected with the first adapter 61 through the first inner welding ring 613, the first middle welding ring 614 and the first outer welding ring 615. The center line of the first inner coil 613, the center line of the first middle coil 614, and the center line of the first outer coil 615 are disposed to coincide. The first middle welding ring 614 is located at the outer periphery of the first inner welding ring 613 and spaced apart from the first inner welding ring 613, the first outer welding ring 615 is located at the outer periphery of the first middle welding ring 614 and spaced apart from the first middle welding ring 614, and the first pole welding part 611 is electrically connected with the first pole 41 through the first inner welding ring 613, the first middle welding ring 614 and the first outer welding ring 615.

In the direction from the center to the edge of the first pole welding portion 611, the radial dimension of the first inner bead 613, the radial dimension of the first middle bead 614, and the radial dimension of the first outer bead 615 are sequentially increased, so that the first inner bead 613, the first middle bead 614, and the first outer bead 615 can take on a structure form in which they are nested one by one.

Illustratively, the first inner weld 613, the first middle weld 614, and the first outer weld 615 may be formed by laser penetration welding the first adapter 61 with the first pole 41. Along the thickness direction of the end cap assembly 100, the first inner welding ring 613 may be disposed so as to protrude from two surfaces of the first pole welding portion 611, or the first inner welding ring 613 may be disposed so as to be recessed from two surfaces of the first pole welding portion 611, and any one or more of the two surfaces of the first inner welding ring 613 disposed so as to be opposite to the first pole welding portion 611 may have an uneven undulating shape. Along the thickness direction of the end cap assembly 100, the first middle welding ring 614 may be provided to protrude from both surfaces of the first pole welding part 611 which are provided opposite to each other, the first middle welding ring 614 may be provided to be recessed from both surfaces of the first pole welding part 611 which are provided opposite to each other, and any one or more of the two surfaces of the first pole welding part 611 which are provided opposite to each other may be provided with an uneven undulating shape or the like. Along the thickness direction of the end cap assembly 100, the first outer ring 615 may be disposed so as to protrude from both surfaces of the first pole welding portion 611 which are disposed opposite to each other, the first outer ring 615 may be disposed so as to be recessed from both surfaces of the first pole welding portion 611 which are disposed opposite to each other, and the first outer ring 615 may be disposed so as to have an uneven undulating shape or the like with respect to any one or more of the two surfaces of the first pole welding portion 611 which are disposed opposite to each other. The shape of the first inner coil 613, the first middle coil 614, and the first outer coil 615 may be generally regular, such as: circular, equilateral triangle, rectangle, polygon, etc., the figure is circular, and the center line is the center of the circle.

In an embodiment of the present application, the first inner weld 613, the first middle weld 614, and the first outer weld 615 are all located in the area of the first array of indentations 616 that is enclosed on the first pole weld 611. In one aspect, the first array of indentations 616 may act as a location to enable the first pole weld 611 to be quickly aligned with the first pole 41 during welding of the first adapter 61 with the first pole 41, which may facilitate improving the welding efficiency of the first adapter 61 with the first pole 41. On the other hand, the first array indentations 616 can improve the surface roughness of the first pole welding portion 611, avoid the damage of the welding laser head caused by the specular reflection of the laser on the smooth surface of the first pole welding portion 611 when the first pole 41 and the first adapter 61 are subjected to laser penetration welding, enable the laser to diffuse reflection on the surface of the first pole welding portion 611 to quickly absorb the laser energy, and further improve the welding efficiency of the first adapter 61 and the first pole 41.

In one possible embodiment, the spacing between the outer edge of the first outer ring 615 and the outer edge of the first array of indentations 616 is greater than or equal to 2mm. With this arrangement, sufficient welding between the first adapter 61 and the first pole 41 can be ensured, and the connection performance between the first adapter 61 and the first pole 41 can be further improved. Illustratively, the spacing between the outer edge of the first outer bead 615 and the outer edge of the first array of indentations 616 is greater than or equal to 2mm in both the length direction of the end cap assembly 100 and the width direction of the end cap assembly 100.

In one possible embodiment, the first array of indentations 616 encloses a region on the first pole weld 611 that is greater than the orthographic projection of the first flange portion 412 on the first pole weld 611. Therefore, the first array indentations 616 can play a role in positioning, so that the first pole welding part 611 of the first adapter piece 61 is aligned with the first flange part 412 of the first pole 41 quickly in the process of welding the first adapter piece 61 with the first pole 41, thereby being beneficial to improving the welding efficiency of the first adapter piece 61 and the first pole 41 and ensuring the welding reliability of the first adapter piece 61 and the first flange part 412 of the first pole 41.

In an embodiment of the present application, the front projection of first inner bead 613 and first middle bead 614 on first pole weld 611 is covered by the front projection of first post 411 on first pole weld 611. In other words, the front projection of first cylinder 411 on first pole welding portion 611 covers the front projection of first inner bead 613 and first middle bead 614 on first pole welding portion 611. It will be appreciated that the first inner bead 613 and the first middle bead 614 mainly serve as current path regions between the first pole 41 and the first tab 41, and by making the front projection of the first post 411 on the first pole welding portion 611 and covering the front projection of the first inner bead 613 and the first middle bead 614 on the first pole welding portion 611, the first tab 61 and the first flange portion 412 of the first pole 41 can be welded together only by the first inner bead 613 and the first middle bead 614, so that the electrical conduction between the first tab 61 and the first tab 41 can be achieved, and a large-area stable electrical connection can be formed between the first tab 61 and the first post 411, thereby improving the overcurrent capability therebetween.

The area of the first outer ring 615 enclosed by the first pole welding portion 611 is larger than the orthographic projection area of the first column 411 on the first pole welding portion 611. Therefore, the first outer welding ring 615 not only can realize the connection between the first adapter piece 61 and the first pole 41, but also can enable the first adapter piece 61 to further compress the first lower plastic 31, so that the first lower plastic 31 is tightly abutted against the end cover 20, and the connection reliability of all parts in the end cover assembly 100 is improved. In addition, the problem that the first pole 41 falls down to the winding core 2220 side due to the softening of the first upper plastic 51 caused by the heat concentration in the column portion region of the first pole 41 when the first adapter 61 is welded to the first pole 41 can be avoided.

With continued reference to fig. 12 and 13, the spacing D1 between the first inner coil 613 and the first middle coil 614 is smaller than the spacing D2 between the first middle coil 614 and the first outer coil 615. It will be appreciated that the first inner coil 613 and the first middle coil 614 mainly serve as current path regions between the first pole 41 and the first adapter 61, and by setting the space between the first inner coil 613 and the first middle coil 614 smaller, a surface connection structure is easily formed, avoiding parasitic capacitance formed between the first inner coil 613 and the first middle coil 614, resulting in current loss. The first outer ring 615 is mainly used as a reinforcing ring for connecting the first pole 41 with the first adapter 61, and the first outer ring 615 has a larger ring diameter to increase the welding area between the first adapter 61 and the first pole 41, thereby further increasing the structural strength of the end cap assembly 100. By the cooperation of the first inner coil 613, the first middle coil 614 and the first outer coil 615, a large-area stable connection structure can be formed between the first adapter 61 and the first pole 41.

In the embodiment of the application, the first inner welding ring 613 is provided with a first welding stress point 6131, the first middle welding ring 614 is provided with a second welding stress point 6141, the first outer welding ring 615 is provided with a third welding stress point 6151, and any two welding marks in the first welding stress point 6131, the second welding stress point 6141 and the third welding stress point 6151 are arranged in a staggered manner along the radial direction of the first outer welding ring 615.

Referring to fig. 14, fig. 14 is a schematic structural diagram of a welding stress point on the first adapter 61 or the second adapter 62 of the end cap assembly 100 shown in fig. 6, and in fig. 14, an arrow indicates a schematic structural diagram of the welding stress point. The welding stress points (the first welding stress point 6131, the second welding stress point 6141 and the third welding stress point 6151) are regions with larger temperature difference of the welded materials, specifically, the starting position of the ring-shaped welding trace (when starting, the temperature of the materials is not raised enough to reach a completely melted state, and the stress is generated in the region) and/or the ending position (in order to ensure uniform welding, the ending position is staggered with the starting position for a small distance, and the ending position at the moment is higher in local temperature due to the fact that the residual temperature of the previous welding is still, and the internal stress is also larger after cooling), so that the welding efficiency is improved, and the starting position and the ending position of the general ring welding coincide. The welding stress points represent a tiny groove on the welding trace of the ring welding, which is obviously different from the regular fish scale-shaped lines on two sides, and the welding stress points can be observed only by naked eyes. The first welding stress point 6131 may identify a start position (end position) of the welding of the first inner race 613, the second welding stress point 6141 may identify a start position (end position) of the welding of the first middle race 614, and the third welding stress point 6151 may identify a start position (end position) of the welding of the first outer race 615.

It will be appreciated that the first weld stress point 6131 may identify a weld start point (end point) of the first inner weld bead 613, which may be a dimple formed by the heat melting of the first adapter piece 61. The second welding stress point 6141 may identify a welding start point (end point) of the first middle weld ring 614, which may be a pit formed by the first adapter 61 melted by heat. The third welding stress point 6151 may identify a welding start point (end point) of the first outer weld ring 615, which may be a pit formed by the first joint 61 melted by heat. By arranging the welding start points (end points) of the three welding rings in a staggered manner in the radial direction of the welding rings, not only can the problem that the structural strength of the first transfer member 61 is insufficient due to the melting of the first transfer member 61 when the welding start points (end points) are concentrated in the same radial direction of the welding rings be avoided. The first adapter 61 can be effectively prevented from being warped due to stress concentration, so that the first pole 41 and the electrode assembly 220 have better electrical connection performance, which is beneficial to improving the service life and the working reliability of the energy storage device 200 applying the end cap assembly 100.

Referring to fig. 7, 15, 16 and 17, fig. 15 is a schematic view illustrating an angle of the second adaptor 62 of the adaptor assembly 60 shown in fig. 7, fig. 16 is a schematic view illustrating another angle of the second adaptor 62 of the adaptor assembly 60 shown in fig. 7, and fig. 17 is a schematic view illustrating an angle of assembling the second adaptor 62 and the second lower plastic 32 shown in fig. 7.

The second adaptor 62 is connected to the third surface 3211 of the second lower plastic 32. The second adapter piece 62 may include a second post weld 621, two second post welds 622, a second inner weld 623, a second middle weld 624, a second outer weld 625, and a second array indentation 626.

The second post welding portion 621 is used for electrically connecting the second adaptor 62 and the second post 42. In one possible embodiment, the width W4 of the second post weld 621 along the length of the end cap assembly 100 satisfies the range: w4 is more than or equal to 24mm and less than or equal to 38mm. It can be appreciated that the second adaptor 62 is a metal piece, and has a greater mechanical strength, and by setting the width W4 of the second post welding portion 621 in the foregoing range, the connection strength between the second adaptor 62 and the second post 42 can be satisfied, so that the second adaptor 62 can be tightly welded to the second post 42, thereby tightly abutting the second lower plastic 32 on the lower surface of the end cap 20, and improving the overall structural strength of the end cap assembly 100.

Two second tab welding portions 622 are connected to the same side of the second tab welding portion 621, and the two second tab welding portions 622 are disposed at intervals in the width direction of the cap assembly 100, so that the second adapter 62 has a C-shape. Each second tab weld 622 is configured to connect with a second tab 2240 of one of the pole cores 2210.

In one possible embodiment, the width W5 of the second tab weld 622 along the width of the end cap assembly 100 satisfies the range: w5 is more than or equal to 14mm and less than or equal to 27mm. It can be appreciated that, by disposing two second lug welding portions 622 on the second adaptor 62, and making the two second lug welding portions 622 far away from the second post 42, when the two second lug welding portions 622 and the two second lugs 2240 are welded, the portions of the second lower plastic 32 corresponding to the two second lug welding portions 622 can be tightly abutted against the end cover 20, so as to reinforce the connection performance of the end cover 20 and the portion of the second lower plastic 32 far away from the second post 42, avoid sagging caused by plastic deterioration and strength degradation after long-term working due to suspension of the middle portion of the second lower plastic 32, and avoid the enlargement of the opening below the explosion-proof valve 11 after the sagging of the second lower plastic 32, so that foreign matters are easier to enter and adhere to the explosion-proof valve 11, and affect the valve opening performance of the explosion-proof valve 11.

Referring to fig. 15 and 16 in combination, the second array of indentations 626 is formed on the surface of the second post-weld 621 facing away from the second lower plastic 32. Illustratively, the second array of indentations 626 may include a plurality of array-disposed spot indentations, with two adjacent spot indentations being spaced apart.

The second inner welding ring 623, the second middle welding ring 624 and the second outer welding ring 625 are all arranged at the second post welding part 621, the second inner welding ring 623, the second middle welding ring 624 and the second outer welding ring 625 are all contacted with the second flange part 422 of the second post 42, and the second flange part 422 is fixedly connected with the second adapter 62 through the second inner welding ring 623, the second middle welding ring 624 and the second outer welding ring 625. The center line of the second inner bead 623, the center line of the second middle bead 624, and the center line of the second outer bead 625 are disposed coincident. The second middle welding ring 624 is located at the outer periphery of the second inner welding ring 623 and spaced apart from the second inner welding ring 623, and the second outer welding ring 625 is located at the outer periphery of the second middle welding ring 624 and spaced apart from the second middle welding ring 624, and the second post welding portion 621 is electrically connected to the second post 42 through the second inner welding ring 623, the second middle welding ring 624, and the second outer welding ring 625.

The radial dimension of the second inner bead 623, the radial dimension of the second middle bead 624, and the radial dimension of the second outer bead 625 increase in order in the direction from the center to the edge of the second post weld 621, thereby enabling the second inner bead 623, the second middle bead 624, and the second outer bead 625 to assume a structure configuration in which they are nested one upon another.

Illustratively, the second inner, middle and outer weld rings 623, 624, 625 may be formed by laser penetration welding the second adapter 62 with the second post 42. Along the thickness direction of the end cap assembly 100, the second inner welding ring 623 may be provided to protrude from both surfaces of the second post welding portion 621, or the second inner welding ring 623 may be provided to recess from both surfaces of the second post welding portion 621, and the second inner welding ring 623 may be provided to have a rugged undulating shape or the like with respect to any one or more of the two surfaces of the second post welding portion 621. Along the thickness direction of the end cap assembly 100, the second middle welding ring 624 may be disposed so as to protrude from two opposite surfaces of the second pillar welding portion 621, the second middle welding ring 624 may be disposed so as to be recessed from two opposite surfaces of the second pillar welding portion 621, and the second middle welding ring 624 may be disposed so as to have an uneven undulating shape with respect to any one or more of the two opposite surfaces of the second pillar welding portion 621. Along the thickness direction of the end cap assembly 100, the second outer bead 625 may be provided to protrude from both surfaces of the second pillar welding portion 621, or the second outer bead 625 may be provided to recess from both surfaces of the second pillar welding portion 621, or the second outer bead 625 may be provided to have an uneven undulating shape or the like with respect to any one or more of the two surfaces of the second pillar welding portion 621. The shape of the second inner bead 623, the second middle bead 624, and the second outer bead 625 may be generally regular, such as: circular, equilateral triangle, rectangle, polygon, etc., the figure is circular, and the center line is the center of the circle.

In an embodiment of the present application, the second inner weld 623, the second middle weld 624, and the second outer weld 625 are all located within the area of the second array of indentations 626 enclosed on the second post weld 621. In one aspect, the second array of indentations 626 may be positioned to provide for rapid alignment of the second post welds 621 with the second post 42 during welding of the second adapter 62 with the second post 42, which may facilitate improved welding efficiency of the second adapter 62 with the second post 42. On the other hand, the second array indentations 626 can improve the surface roughness of the second post welding portion 621, avoid the damage of the welding laser head caused by the specular reflection of the laser on the smooth surface of the second post welding portion 621 when the second post 42 and the second adapter 62 are subjected to laser penetration welding, enable the laser to diffuse reflection on the surface of the second post welding portion 621 to quickly absorb the laser energy, and further improve the welding efficiency of the second adapter 62 and the second post 42.

In one possible embodiment, the spacing between the outer edge of the second outer bond wire 625 and the outer edge of the second array of indentations 626 is greater than or equal to 2mm. With this arrangement, sufficient welding between the second adapter 62 and the second post 42 can be ensured, and the connection performance between the second adapter 62 and the second post 42 can be further improved. Illustratively, the spacing between the outer edge of the second outer bead 625 and the outer edge of the second array of indentations 626 is greater than or equal to 2mm in both the length direction of the end cap assembly 100 and the width direction of the end cap assembly 100.

In one possible embodiment, the second array of indentations 626 encloses a region on the second post weld 621 that is greater than the orthographic projection of the second flange portion 422 on the second post weld 621. Therefore, the second array indentations 626 can play a role in positioning, so that the second post welding portion 621 of the second adapter 62 is aligned with the second flange portion 422 of the second post 42 quickly in the process of welding the second adapter 62 with the second post 42, thereby being beneficial to improving the welding efficiency of the second adapter 62 and the second post 42 and ensuring the welding reliability of the second adapter 62 and the second flange portion 422 of the second post 42.

In an embodiment of the present application, the orthographic projection of the second inner bead 623 and the second middle bead 624 on the second post weld 621 is covered by the orthographic projection of the second post 421 on the second post weld 621. In other words, the front projection of the second post 421 onto the second post weld 621 covers the front projection of the second inner bead 623 and the second middle bead 624 onto the second post weld 621. It will be appreciated that the second inner and middle welding rings 623, 624 mainly serve as current path regions between the second post 42 and the second adapter member 62, and by making the front projection of the second post 421 on the second post welding portion 621 and covering the front projection of the second inner and middle welding rings 623, 624 on the second post welding portion 621, the second adapter member 62 and the second flange portion 422 of the second post 42 can be electrically connected by welding the second inner and middle welding rings 623, 624 together, so that a large-area stable electrical connection can be formed between the second adapter member 62 and the second post 42, and the overcurrent capability therebetween can be improved.

The area of the second outer land 625 enclosed by the second post welding portion 621 is larger than the orthographic projection area of the second post 421 on the second post welding portion 621. Therefore, the second outer welding ring 625 not only can realize the connection between the second adapter piece 62 and the second pole 42, but also can enable the second adapter piece 62 to further compress the second lower plastic 32, so that the second lower plastic 32 is tightly abutted against the end cover 20, and the connection reliability of each component in the end cover assembly 100 is improved. In addition, the problem that the second pole 42 falls down to the core 2220 side due to the softening of the second upper plastic 52 caused by the heat concentration in the pole portion region of the second pole 42 during the welding of the second adapter 62 and the second pole 42 can be avoided.

With continued reference to fig. 16 and 17, the spacing D3 between the second inner bead 623 and the second middle bead 624 is less than the spacing D4 between the second middle bead 624 and the second outer bead 625. It will be appreciated that the second inner coil 623 and the second middle coil 624 mainly serve as current path regions between the second post 42 and the second adapter 62, and by setting the spacing between the second inner coil 623 and the second middle coil 624 smaller, a surface connection structure is easily formed, avoiding parasitic capacitance between the second inner coil 623 and the second middle coil 624, resulting in current loss. The second outer welding ring 625 is mainly used as a reinforcing ring for connecting the second pole 42 with the second adapter 62, and the second outer welding ring 625 has a larger ring diameter to improve the welding area between the second adapter 62 and the second pole 42, thereby further improving the structural strength of the end cover assembly 100. By the cooperation of the second inner coil 623, the second middle coil 624, and the second outer coil 625, a large-area stable connection structure can be formed between the second adapter 62 and the second post 42.

In the embodiment of the present application, the second inner welding ring 623 has a fourth welding stress point 6231, the second middle welding ring 624 has a fifth welding stress point 6241, the second outer welding ring 625 has a sixth welding stress point 6251, and any two welding marks of the fourth welding stress point 6231, the fifth welding stress point 6241 and the sixth welding stress point 6251 are arranged in a staggered manner along the radial direction of the second outer welding ring 625.

Referring to fig. 14, in fig. 14, arrows indicate the structure of the welding stress points. The welding stress points (the fourth welding stress point 6231, the fifth welding stress point 6241 and the sixth welding stress point 6251) are regions with larger temperature difference of the welded materials, specifically, the starting position of the ring-shaped welding trace (when starting, the temperature of the materials is not raised enough to reach the complete melting state, and the stress is generated in the regions) and/or the ending position (in order to ensure uniform welding, the ending position is staggered with the starting position by a small distance, and the ending position at the moment is higher in local temperature due to the residual heat of the previous welding and higher in internal stress after cooling), so as to improve the welding efficiency, and the starting position and the ending position of the general ring welding are overlapped. The welding stress points represent a tiny groove on the welding trace of the ring welding, which is obviously different from the regular fish scale-shaped lines on two sides, and the welding stress points can be observed only by naked eyes. The fourth weld stress point 6231 may identify a start location (end location) for welding the second inner weld ring 623, the fifth weld stress point 6241 may identify a start location (end location) for welding the second middle weld ring 624, and the sixth weld stress point 6251 may identify a start location (end location) for welding the second outer weld ring 625.

It is appreciated that the fourth weld stress point 6231 may identify a weld start point (end point) of the second inner weld ring 623, which may be a dimple formed by the heat melting of the second adapter member 62. The fifth weld stress point 6241 may identify a weld start point (end point) of the second intermediate weld ring 624, which may be a dimple formed by the second adapter 62 melted by heat. The sixth weld stress point 6251 may identify a weld start point (end point) of the second outer weld ring 625, which may be a dimple formed by the second adapter element 62 melted by heat. By arranging the welding start points (end points) of the three welding rings in a staggered manner in the radial direction of the welding rings, not only can the phenomenon that the structural strength of the second adapter piece 62 is insufficient due to the fact that the second adapter piece 62 melts when the welding start points (end points) are concentrated in the same radial direction of the welding rings be avoided. The second adapter 62 can be effectively prevented from warping due to stress concentration, so that the second pole 42 and the electrode assembly 220 have better electrical connection performance, which is beneficial to improving the service life and the working reliability of the energy storage device 200 applying the end cap assembly 100.

Referring again to fig. 7, the insulating film assembly 70 may include one first insulating film 71, one second insulating film 72, two third insulating films 73, two fourth insulating films 74, two fifth insulating films 75, and two sixth insulating films 76. A first insulating film 71 is located between a first post weld 611 and the electrode assembly 220. A second insulating film 72 is located between a second pillar welding portion 621 and the electrode assembly 220. Each of the third insulating films 73 is located between one of the first tab welding parts 612 and the electrode assembly 220. Each of the fourth insulating films 74 is located between one of the first tab welding portions 612 and the first lower plastic 31. Each of the fifth insulating films 75 is located between one of the second tab welding parts 622 and the electrode assembly 220. Each of the sixth insulating films 76 is located between one of the second tab welds 622 and the second lower plastic 32. Illustratively, the first and second insulating films 71 and 72 may be green films, and the third, fourth, fifth, and sixth insulating films 73, 74, 75, and 76 may be green films.

It can be appreciated that by providing the insulating films (the third insulating film 73 and the fourth insulating film 74) on both opposite sides of the first tab welding portion 612, on the one hand, it is possible to prevent the side of the first tab welding portion 612 facing away from the electrode assembly 220 from being scratched by the first lower plastic 31 due to the presence of burrs after the welding is completed. On the other hand, it is possible to prevent the side of the first tab welding part 612 near the electrode assembly 220 from being dropped into the electrode assembly 220 to be short-circuited with the electrode assembly 220 due to metal chips generated by scratch. By providing the insulating films (the fifth insulating film 75 and the sixth insulating film 76) on both opposite sides of the second tab welding portion 622, on the one hand, it is possible to prevent the side of the second tab welding portion 622 facing away from the electrode assembly 220 from rubbing the second lower plastic 32 due to the presence of burrs after the welding is completed. On the other hand, it is possible to prevent the side of the second tab welding part 622, which is close to the electrode assembly 220, from being dropped into the electrode assembly 220 to be short-circuited with the electrode assembly 220 due to metal chips generated by scratch. In addition, the fourth insulating film 74 and the sixth insulating film 76 have a certain thickness, and are inserted between the adaptor (the first adaptor 61 or the second adaptor 62) and the lower plastic (the first lower plastic 31 or the second lower plastic 32), so that the strength of the end, away from the pole, of the adaptor, against the lower plastic can be further improved, and the bonding degree between the lower plastic and the end cover 20 can be further improved.

By providing the first insulating film 71 on the side of the first pole welding portion 611 facing the electrode assembly 220, it is possible to prevent the side of the first pole welding portion 611 near the electrode assembly 220 from being dropped into the electrode assembly 220 to be connected to the electrode assembly 220 by short-circuiting due to metal chips generated by scratch. By providing the second insulating film 72 at the side of the second pillar welding portion 621 facing the electrode assembly 220, it is possible to prevent the side of the second pillar welding portion 621 adjacent to the electrode assembly 220 from being dropped into the electrode assembly 220 to be short-circuited with the electrode assembly 220 due to metal chips generated by scratch.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of embodiments of the application, the meaning of "plurality" means two or more than two, unless specifically defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: there are three cases, a, B, a and B simultaneously. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like should be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.

Finally, it should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the above-mentioned preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made to the technical solution of the present application without departing from the spirit and scope of the technical solution of the present application.

Claims

1. An end cap assembly, said end cap assembly comprising:

the first lower plastic comprises a first surface facing the electrode assembly, the first lower plastic is provided with a first pole through hole, the first pole through hole comprises a first hole and a second hole which are communicated, and the aperture size of the second hole is larger than that of the first hole;

The first pole is arranged in the first lower plastic in a penetrating mode and comprises a first column body and a first flange part, the first column body is arranged on the first flange part in a protruding mode, part of the first column body is located in the first hole, the first flange part is located in the second hole, and the surface, deviating from the first column body, of the first flange part is flush with the first surface;

the first inner welding ring is provided with a first welding stress point, the first middle welding ring is provided with a second welding stress point, the first outer welding ring is provided with a third welding stress point, and any two welding stress points among the first welding stress point, the second welding stress point and the third welding stress point are arranged in a staggered manner along the radial direction of the first outer welding ring;

The area of the first outer welding ring, which is surrounded on the first pole welding part, is larger than the orthographic projection area of the first column body on the first pole welding part;

the first flange part is fixedly connected with the first adapter through the first inner welding ring, the first middle welding ring and the first outer welding ring;

and the orthographic projection of the first cylinder on the first pole welding part covers orthographic projections of the first inner welding ring and the first middle welding ring on the first pole welding part.

2. The end cap assembly of claim 1, wherein a spacing between the first inner and first middle weld rings is less than a spacing between the first middle weld ring and the first outer weld ring.

3. The end cap assembly of claim 1, wherein the first adapter further comprises a first array of indentations disposed on a surface of the first post weld facing away from the first lower plastic, the first inner weld ring, the first middle weld ring, and the first outer weld ring being located within an area of the first array of indentations defined on the first post weld.

4. The end cap assembly of claim 3, wherein a spacing between an outer edge of the first outer bead and an outer edge of the first array of indentations is greater than or equal to 2mm.

5. The end cap assembly of claim 3, wherein the first array of indentations encloses a region on the first post weld that is greater than an orthographic projection of the first flange portion on the first post weld.

6. The end cap assembly according to claim 1 or 2, wherein the first adapter further comprises two first tab welding portions connected to the same side of the first tab welding portions, the two first tab welding portions being disposed at intervals in a width direction of the end cap assembly;

7. The end cap assembly of claim 6, wherein the first lower plastic further comprises a first retaining wall circumferentially disposed about the periphery of the first lower plastic body in a circumferential direction of the first lower plastic body, the first retaining wall protruding relative to the first surface of the first lower plastic body, the first retaining wall and the first lower plastic body cooperatively defining a first cavity capable of receiving a portion of the first adapter.

8. The end cap assembly of claim 1 or 2, wherein the width W1 of the first post weld along the length of the end cap assembly satisfies the range: w1 is more than or equal to 24mm and less than or equal to 38mm.

9. The end cap assembly of claim 6, wherein a width W2 of the first tab weld along a width direction of the end cap assembly satisfies the range: w2 is more than or equal to 14mm and less than or equal to 27mm.

10. The end cap assembly of claim 6, wherein a spacing W3 between the first post weld and the shunt portion along a length of the end cap assembly satisfies the range: w3 is more than or equal to 0.5mm and less than or equal to 2.5mm.

11. An energy storage device comprising an electrode assembly and an end cap assembly according to any one of claims 1-10, wherein the electrode assembly is electrically connected to the end cap assembly.

12. An energy storage system comprising the energy storage device of claim 11.