Energy storage apparatus and electrical device

Abstract

The present application discloses an energy storage apparatus and an electrical device. The energy storage apparatus comprises an electrode assembly and an end cover assembly. The electrode assembly comprises a first tab and a second tab. The thickness of the first tab is greater than the thickness of the second tab, the resistivity of the first tab is greater than the resistivity of the second tab, and the cross section of the first tab is greater than the cross section of the second tab. The end cover assembly is mounted at an end of the electrode assembly, and comprises a lower plastic member, a first lead, and a second lead. The lower plastic member comprises a first assembly end surface and a second assembly end surface. The first lead comprises a first adapter portion, the first adapter portion comprising a first outer adapter surface facing a same direction as the first assembly end surface. The second lead comprises a second adapter portion, the second adapter portion comprising a second outer adapter surface facing a same direction as the second assembly end surface. In the length direction of an end cover, the first outer adapter surface is at a first distance from the first assembly end surface, and the second outer adapter surface is at a second distance from the second assembly end surface, the second distance being less than the first distance.

Description

An energy storage device and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 2024117322364, filed on November 29, 2024, entitled “An Energy Storage Device and Electrical Equipment”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of energy storage technology, and in particular to an energy storage device and electrical equipment. Background Technology

[0003] As the demand for secondary energy storage devices increases, people are also placing higher demands on the performance of these devices in all aspects, especially on their energy density.

[0004] Typically, the positive and negative electrode tabs in energy storage devices are made of different materials, resulting in different current conductivity levels. Poor current conductivity of the tabs can lead to excessive localized temperature rise, affecting battery performance and safety. Summary of the Invention

[0005] This application provides an energy storage device and electrical equipment that can avoid excessive local temperature rise of the electrode tab, and avoid the problem of difficult electrode tab assembly without affecting the energy density.

[0006] In a first aspect, this application provides an energy storage device, comprising:

[0007] case;

[0008] An electrode assembly, housed within the housing, includes a battery cell, a first electrode tab, and a second electrode tab. The first and second electrode tabs extend from opposite sides of the battery cell along its length. The thickness of the first electrode tab is greater than the thickness of the second electrode tab, the resistivity of the first electrode tab is greater than the resistivity of the second electrode tab, and the cross-section of the first electrode tab is greater than the cross-section of the second electrode tab.

[0009] An end cap assembly is mounted on one end of the electrode assembly and seals the housing. The end cap assembly includes an end cap, a lower plastic body, a first pin, a second pin, a first electrode post, and a second electrode post. The lower plastic body includes a lower plastic body, which includes a first mounting end face and a second mounting end face. The first mounting end face and the second mounting end face are arranged opposite to each other along the length direction of the lower plastic body.

[0010] The first pin includes a first connecting portion and a first adapter portion. The first adapter portion is connected to the first connecting portion and is disposed at an angle to the first connecting portion. The first connecting portion is mounted at one end of the lower plastic along its length. The first adapter portion extends away from the lower plastic and is connected to and electrically connected to the first electrode tab. The first adapter portion includes a first outer adapter surface, the orientation of which is the same as the orientation of the first mounting end face. Along the length of the end cap, the first outer adapter surface is at a first distance from the first mounting end face.

[0011] The second pin includes a second adapter portion and a second connecting portion. The second adapter portion and the second connecting portion are connected and are arranged at an angle to each other. The second connecting portion is mounted at the other end of the lower plastic in the length direction. The second adapter portion extends away from the lower plastic and is connected to the second electrode and electrically connected. The second adapter portion includes a second outer adapter surface. The orientation of the second outer adapter surface is the same as the orientation of the second mounting end face. Along the length direction of the end cap, the second outer adapter surface has a second distance from the second mounting end face. The second distance is less than the first distance.

[0012] The lower plastic and the end cap are stacked along the height direction of the end cap assembly. The first pole and the second pole are both inserted through the end cap and the lower plastic. The first pole is connected to the first connecting part and is electrically conductive, and the second pole is connected to the second connecting part and is electrically conductive.

[0013] It is understood that the battery cell includes a first side surface and a second side surface, with a first tab extending from the first side surface and a second tab extending from the second side surface. In related technologies, since the positions of the first and second poles are symmetrical about the central cross-section of the lower plastic in the width direction, and the first and second pins are symmetrical about the central cross-section of the end cap assembly in the width direction, the first distance from the first outer contact surface of the first pin to the first mounting end face of the first lower plastic is equal to the second distance from the second outer contact surface of the second pin to the second mounting end face of the second lower plastic. The distance from the second side surface of the battery cell to the housing is equal to the distance from the first side surface of the battery cell to the housing. To ensure consistent current conduction capacity of the positive and negative electrodes of the energy storage device and to avoid excessive local temperature rise of the tabs, the thickness of the first tab needs to be greater than the thickness of the second tab, and the cross-section of the first tab is greater than the cross-section of the second tab. Therefore, when the electrode assembly and end cap assembly are assembled to the housing, the distance from the second tab to the housing is greater than the distance from the first tab to the housing, resulting in inconsistent distances from the two sides of the electrode assembly along its length to the housing. If the distance from the second side surface of the cell to the casing is just enough to accommodate the second tab, then assembling the first tab will be difficult. If the distance from the first side surface of the cell to the casing is enough to accommodate the first tab, then the distance from the second tab to the casing will be redundant, resulting in wasted space between the end cap assembly and the tab. This will prevent full utilization of the internal space of the energy storage device and reduce its energy density.

[0014] In this embodiment, the battery cell located between the first and second adapter portions is offset towards the second electrode post. This results in a first distance from the first outer adapter surface of the first adapter portion to the first mounting end face of the first lower plastic being greater than a second distance from the second outer adapter surface of the second adapter portion to the second mounting end face of the second lower plastic. The distance from the first side surface of the battery cell to the housing is greater than the distance from the second side surface of the battery cell to the housing. Furthermore, the gap between the first side surface of the battery cell and the housing is sufficient to accommodate the thicker first electrode tab, while the gap between the second side surface of the battery cell and the housing is sufficient to accommodate the thinner second electrode tab, thus avoiding difficulties in assembling the first electrode tab. In addition, the distance from the first electrode tab to the housing is approximately equal to the distance from the second electrode tab to the housing. This not only allows for the smooth installation of both the first and second electrodes into the housing but also avoids inconsistencies in the distances from the two sides of the electrode assembly along its length to the housing, effectively utilizing the redundant space between the second electrode tab and the housing and improving the energy density of the energy storage device.

[0015] Secondly, this application provides an electrical device, including the energy storage device, which supplies power to the electrical device. Attached Figure Description

[0016] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 is an application scenario diagram of the energy storage device provided in the embodiment of this application;

[0018] Figure 2 is a schematic diagram of the energy storage device provided in an embodiment of this application;

[0019] Figure 3 is a schematic diagram of the exploded structure of the energy storage device shown in Figure 2;

[0020] Figure 4 is an exploded structural diagram of the end cap assembly in the energy storage device shown in Figure 2.

[0021] Figure 5 is a structural schematic diagram of the first lower plastic part of the end cap assembly shown in Figure 4 from another angle;

[0022] Figure 6 is a structural schematic diagram of the second lower plastic part of the end cap assembly shown in Figure 4 from another angle;

[0023] Figure 7 is a schematic cross-sectional view of the end cap assembly in the energy storage device shown in Figure 2;

[0024] Figure 8 is a schematic diagram of the cross-sectional structure of the energy storage device shown in Figure 2.

[0025] The terms corresponding to the reference numerals in the figures are as follows: energy storage device 1000, end cap assembly 100, end cap 10, upper surface 11, lower surface 12, first end face 101, second end face 102, assembly groove 13, first lower plastic 20, first assembly end face M1, first connecting end face N1, first body 21, first top surface 211, first bottom surface 212, first rib 22, first mounting groove 23, first groove bottom wall 231, first groove side wall 232, second groove side wall 233, first heat-melting part 24, inner surface 241, first connecting surface 242, first pole post through hole 25. First limiting post 26, first protrusion 27, first boss 28, first boss surface 281, first outer surface 282, second lower plastic part 30, second assembly end face M2, second connecting end face N2, second body 31, second top surface 311, second bottom surface 312, second rib 32, second mounting groove 33, second groove bottom wall 331, third groove side wall 332, fourth groove side wall 333, second heat-melting part 34, clearance surface 341, second connecting surface 342, second pole post through hole 35, second limiting post 36, second protrusion 37, second boss 38, second boss surface 381. Second outer surface 382, ​​first pin 40, first connecting part 41, first inner connecting surface 411, first outer connecting surface 412, first through hole 413, first limiting hole 414, first adapter part 42, first outer adapter surface 421, first inner adapter surface 422, second pin 50, second connecting part 51, second inner connecting surface 511, second outer connecting surface 512, second through hole 513, second limiting hole 514, second adapter part 52, second outer adapter surface 521, second inner adapter surface 522, first electrode post 60, second electrode post 70, electrode assembly 200, battery cell 21 0. First side surface 210a, second side surface 210b, first tab 220, second tab 230, housing 300, opening 301, receiving cavity 302, protective film 400, energy storage system 5000, first power conversion device 4100, second power conversion device 4200, first electrical device 3000, second electrical device 2000, first distance D1, second distance D2, first gap Q1, second gap Q2, first spacing S1, second spacing S2, first straight distance P1, second straight distance P2, first length L1, second length L2. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly specified. Furthermore, the terms "same," "equal," or "parallel" used below are all allowed to have certain tolerances.

[0028] It should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0029] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form according to future application needs. As we all know, to achieve the grand goal of carbon neutrality, the main way to generate green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels. Currently, the generation of green electricity generally relies on photovoltaics, wind power, and hydropower. However, wind and solar energy generally suffer from strong intermittency and large fluctuations, which can cause grid instability, insufficient electricity during peak demand periods, and excessive electricity during off-peak periods. Unstable voltage can also damage the power grid. Therefore, insufficient electricity demand or insufficient grid capacity may lead to the problem of "wind and solar curtailment." Solving these problems requires energy storage. Energy storage involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, the stored energy is converted back into electrical energy and released. Simply put, energy storage is like a large "power bank". When there is sufficient solar and wind power, electrical energy is stored and the stored power is released when needed.

[0030] Taking electrochemical energy storage as an example, this application provides an energy storage device 1000. The energy storage device 1000 is equipped with a set of chemical batteries. It mainly uses the chemical elements in the chemical batteries as energy storage medium. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage medium. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electrical energy is released for use, or transferred to places with a shortage of electricity for use.

[0031] Current energy storage applications are quite widespread, including energy storage on the (wind and solar) power generation side, grid-side energy storage, base station-side energy storage, and user-side energy storage. The corresponding energy storage devices include:

[0032] (1) Large energy storage containers used in grid-side energy storage scenarios can serve as high-quality active and reactive power regulation power sources in the grid, enabling load matching of electrical energy in time and space, enhancing the absorption capacity of renewable energy, and playing a significant role in grid system backup, alleviating peak load power supply pressure, and peak regulation and frequency regulation.

[0033] (2) Small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side mainly operate under the "peak shaving and valley filling" mode.

[0034] Because there are significant price differences in electricity during peak and off-peak periods depending on electricity demand, users with energy storage devices typically charge the storage cabinets / boxes during off-peak periods to reduce costs, and then release the electricity from the storage devices for use during peak periods, in order to save on electricity bills.

[0035] It should be noted that the aforementioned energy storage containers, small and medium-sized energy storage cabinets, and household small energy storage boxes, which contain energy storage devices 1000, can be understood as electrical equipment.

[0036] Please refer to Figure 1, which is an application scenario diagram of the energy storage device provided in the embodiments of this application.

[0037] The energy storage device 1000 provided in this application embodiment is applied to an energy storage system 5000. The energy storage system 5000 includes a first power conversion device 4100 (photovoltaic panel), a second power conversion device 4200 (wind turbine), a first electrical device 3000 (grid), a second electrical device 2000 (base station), and the energy storage device 1000. The energy storage system 5000 also includes an energy storage cabinet, in which the energy storage device 1000 is installed. The energy storage cabinet can be installed outdoors. Specifically, the first power conversion device 4100 can convert solar energy into electrical energy during periods of low electricity prices. The energy storage device 1000 stores this electrical energy and supplies it to the first electrical device 3000 or the second electrical device 2000 during peak electricity demand periods, or provides power when the first electrical device 3000 or the second electrical device 2000 experiences a power outage. The second power conversion device 4200 can convert wind energy into electrical energy. The energy storage device 1000 is used to store the electrical energy and supply it to the first electrical device 3000 or the second electrical device 2000 during peak electricity consumption, or to supply power when the first electrical device 3000 or the second electrical device 2000 experiences a power outage. The electrical energy can be transmitted using high-voltage cables.

[0038] It should be noted that the energy storage device 1000 supplies power to electrical equipment.

[0039] The number of energy storage devices 1000 can be multiple, and the multiple energy storage devices 1000 can be connected in series or in parallel. In this embodiment, "multiple" means two or more.

[0040] It is understood that the energy storage device 1000 may include, but is not limited to, single-cell batteries, battery modules, battery packs, and battery systems. The actual application form of the energy storage device 1000 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. For example, the energy storage device 1000 may be a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid (or lead-acid) battery, a lithium-ion battery, a polymer lithium-ion battery, or other rechargeable batteries. When the energy storage device 1000 is a single-cell battery, it may be a cylindrical battery, a prismatic battery, or a battery of other shapes. In this embodiment, the energy storage device 1000 is described using a prismatic battery as an example. The prismatic battery is a rechargeable battery.

[0041] Please refer to Figures 2 and 3. Figure 2 is a structural schematic diagram of the energy storage device provided in the embodiment of this application, and Figure 3 is an exploded structural schematic diagram of the energy storage device shown in Figure 2.

[0042] For ease of description, the width of the energy storage device 1000 is defined as the X-axis, the length as the Y-axis, and the height as the Z-axis. The X-axis, Y-axis, and Z-axis are all perpendicular to each other.

[0043] The directional terms such as "upper," "top," "lower," "bottom," "left," and "right" mentioned in the description of the embodiments in this application are based on the orientation shown in Figure 2 of the specification and do not constitute a limitation on the energy storage device 1000 in actual application scenarios. Specifically, the positive direction toward the Z-axis is defined as the top of the energy storage device 1000, and the negative direction toward the Z-axis is defined as the bottom of the energy storage device 1000.

[0044] The energy storage device 1000 includes an end cap assembly 100, an electrode assembly 200, a housing 300, and a protective film 400. The housing 300 has an opening 301 and a receiving cavity 302. The opening 301 and the receiving cavity 302 are in communication. Both the electrode assembly 200 and the protective film 400 are housed within the receiving cavity 302. The protective film 400 covers the periphery and bottom of the electrode assembly 200 and separates the electrode assembly 200 from the housing 300 to prevent short circuits caused by contact between the electrode assembly 200 and the housing 300. The end cap assembly 100 is mounted on one end of the electrode assembly 200 and seals the opening 301 to isolate the internal and external environments of the energy storage device 1000. In this embodiment, the housing 300 is rectangular in shape and is made of aluminum.

[0045] In this embodiment, the protective film 400 can be Mylar film. In some embodiments, the protective film 400 can also be made of insulating materials, such as polyethylene (PE), polypropylene (PP), polyester, etc.

[0046] In this embodiment, as shown in FIG3, the electrode assembly 200 has a stacked structure. The electrode assembly 200 includes a cell 210 and tabs. The cell 210 is formed by stacking a positive electrode sheet, a negative electrode sheet, and an insulating film located between the positive and negative electrode sheets. Both the positive and negative electrode sheets include a first portion coated with active material and a second portion of uncoated active material extending outward from the first portion. The cell 210 includes a first side surface 210a and a second side surface 210b. The first side surface 210a and the second side surface 210b are arranged opposite to each other along the length direction (i.e., the Y-axis direction) of the cell 210. There are two cells 210. The two cells 210 are connected side by side along the Y-axis direction. The shape of the cell 210 is approximately cuboid. In some other embodiments, the electrode assembly 200 may also be a wound structure. The cell 210 is formed by winding a positive electrode sheet, a negative electrode sheet, and an insulating film located between the positive and negative electrode sheets.

[0047] The electrode includes a first electrode 220 and a second electrode 230. Both the first electrode 220 and the second electrode 230 are electrically connected to the battery cell 210. Along the Y-axis, the first electrode 220 extends from the first side surface 210a of the battery cell 210, and the second electrode 230 extends from the second side surface 210b of the battery cell 210. In this embodiment, the first electrode 220 can be a positive electrode, and the second electrode 230 can be a negative electrode. The positive electrode corresponds to the second portion of the positive electrode sheet that is not coated with active material, and the positive electrode is made of aluminum. The negative electrode corresponds to the second portion of the negative electrode sheet that is not coated with active material, and the negative electrode is made of copper. There are two of each type of electrode. The two first electrodes 220 and the two second electrodes 230 are bent relative to each other along the X-axis. In some embodiments, the first electrode 220 can be a negative electrode, and the second electrode 230 can be a positive electrode. The first electrode 220 can be made of materials not limited to aluminum, and the second electrode 230 can be made of materials not limited to copper.

[0048] It should be noted that, because copper has a higher conductivity than aluminum, when the first tab 220 and the second tab 230 have the same dimensions, the second tab 230 has a higher conductivity than the first tab 220. This can easily lead to excessive local temperature rise in the second tab 230, affecting the performance and safety of the energy storage device 1000. In practical applications, the dimensions of the first tab 220 are designed to be larger than those of the second tab 230, and the resistivity of the first tab 220 is greater than that of the second tab 230. This ensures that the conductivity of the first tab 220 and the second tab 230 are consistent, thereby ensuring that the conductivity of the positive and negative electrodes of the energy storage device 1000 is consistent. For example, the thickness of the first tab 220 is set to be greater than that of the second tab 230, and the cross-section of the first tab 220 is larger than that of the second tab 230.

[0049] In related technologies, the end cap assembly in the energy storage device 1000 typically adopts a symmetrical design, such as the distance from the first side surface 210a of the cell 210 to the housing 300 being equal to the distance from the second side surface 210b of the cell 210. When the electrode assembly 200 is installed into the housing 300, since the thickness of the first tab 220 needs to be greater than the thickness of the second tab 230, if the distance from the second side surface 210b of the cell 210 to the housing 300 just meets the thickness of the second tab 230, then the assembly of the first tab 220 becomes difficult; if the distance from the first side surface 210a of the cell 210 to the housing 300 meets the installation of the first tab 220, then the distance from the second tab 230 to the housing 300 is redundant. Therefore, there is a waste of space between the end cap assembly and the tabs, which prevents full utilization of the internal space of the energy storage device 1000 and reduces the energy density of the energy storage device 1000.

[0050] The end cap assembly 100 of this application embodiment can ensure the smooth assembly of the first tab 220 and the second tab 230, and at the same time can make full use of the internal space of the energy storage device 1000 to improve the energy density of the energy storage device 1000.

[0051] Please refer to Figure 4, which is an exploded structural diagram of the end cap assembly in the energy storage device shown in Figure 2.

[0052] In this embodiment, the end cap assembly 100 includes an end cap 10, a lower plastic layer, a first pin 40, a second pin 50, a first terminal 60, and a second terminal 70. The lower plastic layer and the end cap 10 are stacked along the height direction (i.e., the Z-axis direction) of the end cap assembly 100. The first terminal 60 and the second terminal 70 are located at opposite ends along the length direction (i.e., the Y-axis direction) of the end cap assembly 100. The first pin 40 and the second pin 50 are respectively mounted at opposite ends along the length direction (i.e., the Y-axis direction) of the lower plastic layer. The first terminal 60 passes through the end cap 10 and the lower plastic layer and is connected to the first pin 40. The second terminal 70 passes through the end cap 10 and the lower plastic layer and is connected to the second pin 50. The first terminal 60 is a positive terminal, and the second terminal 70 is a negative terminal. In other embodiments, the first terminal 60 is a negative terminal, and the second terminal 70 is a positive terminal.

[0053] In this embodiment, the end cap 10 is a long, thin strip. The end cap 10 is made of plain aluminum. The end cap 10 includes an upper surface 11 and a lower surface 12. The upper surface 11 and the lower surface 12 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the end cap 10. The end cap 10 also includes a first end face 101 and a second end face 102. The first end face 101 and the second end face 102 are arranged opposite to each other along the length direction of the end cap 10.

[0054] The end cap 10 also includes a mounting groove 13, which is recessed into the lower surface 12 of the end cap 10. Along the thickness direction of the end cap 10, the mounting groove 13 is recessed from the lower surface 12 towards the upper surface 11. The mounting groove 13 is used to accommodate a portion of the lower plastic. In this embodiment, the mounting groove 13 is an elongated groove.

[0055] In this embodiment, the first pin 40 is a metal sheet. The first pin 40 includes a first connecting portion 41 and a first adapter portion 42. The first connecting portion 41 and the first adapter portion 42 are connected, and the length extension direction of the first connecting portion 41 and the length extension direction of the first adapter portion 42 intersect, forming an angle between them and creating an "L"-shaped structure. The first connecting portion 41 is used to connect to and be electrically connected to the first terminal 60. The first adapter portion 42 is used to connect to and be electrically connected to the first tab 220 of the battery cell 210. It can be understood that the first pin 40 is used to transfer the current of the battery cell 210 to the first terminal 60 through the first adapter portion 42 and the first connecting portion 41.

[0056] Specifically, the first connecting portion 41 includes a first inner connecting surface 411 and a first outer connecting surface 412. The first inner connecting surface 411 and the first outer connecting surface 412 are disposed opposite to each other along the thickness direction of the first connecting portion 41. The first connecting portion 41 also has a first through hole 413. The first through hole 413 penetrates through the first inner connecting surface 411 and the first outer connecting surface 412 of the first connecting portion 41. The first through hole 413 is used for the first pole post 60 to pass through. In this embodiment, the first through hole 413 is circular.

[0057] The first connecting portion 41 also includes a plurality of first limiting holes 414. The plurality of first limiting holes 414 all penetrate the first inner connecting surface 411 and the first outer connecting surface 412 of the first connecting portion 41. The first limiting holes 414 are spaced apart around the periphery of the first through hole 413, and the plurality of first limiting holes 414 are spaced apart from each other. The first limiting holes 414 are used to mate with the first lower plastic 20 and to assemble and position the first pin 40 to the first lower plastic 20. In this embodiment, the first limiting holes 414 are circular holes. The number of first limiting holes 414 is two.

[0058] In this embodiment, the first adapter portion 42 is a rectangular sheet. The first adapter portion 42 includes a first outer adapter surface 421 and a first inner adapter surface 422. The first outer adapter surface 421 and the first inner adapter surface 422 are disposed opposite to each other along the thickness direction of the first adapter portion 42. The first outer adapter surface 421 of the first adapter portion 42 is connected to the first outer connecting surface 412 of the first connecting portion 41. The first inner adapter surface 422 of the first adapter portion 42 is connected to the first inner connecting surface 411 of the first connecting portion 41.

[0059] In this embodiment, the second pin 50 is a metal sheet. The second pin 50 includes a second connecting portion 51 and a second adapter portion 52. The second connecting portion 51 and the second adapter portion 52 are connected, and the length extension direction of the second connecting portion 51 intersects the length extension direction of the second adapter portion 52, forming an L-shaped structure with an included angle between them. The second connecting portion 51 is used to connect to and be electrically connected to the second terminal 70. The second adapter portion 52 is used to connect to and be electrically connected to the second tab 230 of the battery cell 210. It can be understood that the second pin 50 is used to transfer the current of the battery cell 210 to the second terminal 70 through the second adapter portion 52 and the second connecting portion 51.

[0060] Specifically, the second connecting portion 51 includes a second inner connecting surface 511 and a second outer connecting surface 512. The second inner connecting surface 511 and the second outer connecting surface 512 are disposed opposite to each other along the thickness direction of the second connecting portion 51. The second connecting portion 51 also has a second through hole 513. The second through hole 513 passes through the second inner connecting surface 511 and the second outer connecting surface 512 of the second connecting portion 51. The second through hole 513 is used for the second pole post 70 to pass through. In this embodiment, the second through hole 513 is circular.

[0061] The second connecting portion 51 also includes a plurality of second limiting holes 514. The plurality of second limiting holes 514 all penetrate the second inner connecting surface 511 and the second outer connecting surface 512 of the second connecting portion 51. The second limiting holes 514 are spaced apart at the periphery of the second through hole 513, and the plurality of second limiting holes 514 are spaced apart from each other. The second limiting holes 514 are used to mate with the second lower plastic 30 and to assemble and position the second pin 50 with the second lower plastic 30. In this embodiment, the second limiting holes 514 are circular holes. The number of second limiting holes 514 is two.

[0062] In this embodiment, the second adapter portion 52 is a rectangular sheet. The second adapter portion 52 includes a second outer adapter surface 521 and a second inner adapter surface 522. The second outer adapter surface 521 and the second inner adapter surface 522 are disposed opposite to each other along the thickness direction of the second adapter portion 52. The second outer adapter surface 521 of the second adapter portion 52 is connected to the second outer connecting surface 512 of the second connecting portion 51. The second inner adapter surface 522 of the second adapter portion 52 is connected to the second inner connecting surface 511 of the second connecting portion 51.

[0063] In this embodiment, the structure of the first pin 40 is the same as or similar to that of the second pin 50, but the size of the first pin 40 and the size of the second pin 50 are different. For example, the first length L1 of the first connecting portion 41 of the first pin 40 is less than the second length L2 of the second connecting portion 51 of the second pin 50.

[0064] In this embodiment, the lower plastic is a long, thin strip. The lower plastic is made of plastic and is insulating. The lower plastic includes a first lower plastic 20 and a second lower plastic 30. The first lower plastic 20 and the second lower plastic 30 are separate structures. The dimensions of the first lower plastic 20 and the second lower plastic 30 can be the same or different. For example, the length of the first lower plastic 20 is greater than the length of the second lower plastic 30. In other embodiments, the first lower plastic 20 and the second lower plastic 30 can also be a single, integrated structure.

[0065] Please refer to Figures 4 and 5 together. Figure 5 is a structural schematic diagram of the first lower plastic part of the end cap assembly shown in Figure 4 from another angle.

[0066] In this embodiment, the first lower plastic 20 is a long strip of thin sheet. The first lower plastic 20 includes a first body 21. The first body 21 includes a first top surface 211 and a first bottom surface 212. The first top surface 211 and the first bottom surface 212 are disposed opposite to each other along the thickness direction (i.e., the Z-axis direction) of the first body 21. The first body 21 also includes a first mounting end surface M1 and a first connecting end surface N1. The first mounting end surface M1 and the first connecting end surface N1 are respectively the opposite ends of the length direction (i.e., the Y-axis direction) of the first lower plastic 20.

[0067] As shown in Figure 5, the first lower plastic 20 also includes two first protruding ribs 22. Both first protruding ribs 22 protrude from the first bottom surface 212 of the first body 21. Along the width direction (i.e., the X-axis direction) of the first lower plastic 20, the two first protruding ribs 22 are located at opposite side edges of the first body 21. Both first protruding ribs 22 extend along the length direction of the first lower plastic 20. In this embodiment, the length of both first protruding ribs 22 is equal to the length of the first body 21 (allowing for certain manufacturing tolerances).

[0068] The first lower plastic 20 also includes a first boss 28 to accommodate the functional design needs of the first lower plastic 20. The first boss 28 protrudes from the first bottom surface 212 of the first body 21. Along the X-axis, the first boss 28 is spaced apart from two first ribs 22. Along the Y-axis, the first boss 28 is located at one end of the length direction of the first body 21. Specifically, the first boss 28 includes a first boss surface 281 and a first outer surface 282. The first boss surface 281 is away from the first body 21, and the orientation of the first boss surface 281 is the same as the orientation of the first bottom surface 212 of the first body 21. The first outer surface 282 connects the first boss surface 281 and the first mounting end face M1 of the first body 21. In this embodiment, the first boss 28 is approximately a rectangular protrusion.

[0069] The first lower plastic 20 also includes a first mounting groove 23. The first mounting groove 23 is recessed into the first boss surface 281 of the first boss 28 and is recessed towards the first body 21. The first mounting groove 23 is used to accommodate the first connecting portion 41 of the first pin 40, and the shape of the first mounting groove 23 matches the first connecting portion 41. The first boss surface 281 can be understood as the surface of the first lower plastic 20.

[0070] Specifically, the first mounting groove 23 includes a first groove bottom wall 231, a first groove side wall 232, and a second groove side wall 233. The orientation of the first groove bottom wall 231 is the same as the first bottom surface 212 of the first body 21. The first groove side wall 232 and the second groove side wall 233 are connected, and the first groove side wall 232 and the second groove side wall 233 together surround and connect to the first groove bottom wall 231. It can be understood that the first groove side wall 232 and the second groove side wall 233 together form the groove peripheral wall of the first mounting groove 23. The first groove side wall 232 is closer to the first assembly end face M1 of the first body 21 than the second groove side wall 233.

[0071] The first lower plastic 20 also includes a first heat-melting portion 24. The first heat-melting portion 24 protrudes from the first boss surface 281 of the first boss 28 and connects the first outer side surface 282 of the first boss 28 and the first groove sidewall 232. The first heat-melting portion 24 is used to connect with the protective film 400 via a heat-melting process. It can be understood that the first heat-melting portion 24 protrudes from the end face of the first groove sidewall 232 of the first mounting groove 23.

[0072] In this embodiment, the first heat-melting portion 24 is a strip-shaped protrusion with a rectangular cross-section. The first heat-melting portion 24 includes an inner surface 241 and a first connecting surface 242. The inner surface 241 and the first connecting surface 242 are arranged opposite to each other along the thickness direction (i.e., the Y-axis direction) of the first heat-melting portion 24. The first connecting surface 242 is connected to the first outer surface 282 of the first boss 28. The inner surface 241 is connected to the first groove sidewall 232 of the first mounting groove 23. In some other embodiments, the first heat-melting portion 24 is connected to the first outer surface 282 and spaced apart from the first groove sidewall 232 of the first mounting groove 23. It is understood that the thickness of the first heat-melting portion 24 is less than or equal to the thickness of the first groove sidewall 232 of the first mounting groove 23.

[0073] It should be noted that one of the dashed lines in Figure 5 is the boundary line between the first heat-melting part 24 and the first boss 28, that is, the boundary line between the first connecting surface 242 of the first heat-melting part 24 and the first outer surface 282 of the first boss 28. The other dashed line is the boundary line between the first boss 28 and the first body 21, that is, the boundary line between the first outer surface 282 of the first boss 28 and the first mounting end face M1 of the first body 21.

[0074] In some embodiments, the first lower plastic 20 does not have a first boss 28, and the first mounting groove 23 is directly recessed into the first bottom surface 212 of the first body 21. Along the thickness direction (i.e., the Z-axis direction) of the first lower plastic 20, the first mounting groove 23 is formed by recessing from the first bottom surface 212 towards the first top surface 211. Along the width direction of the first lower plastic 20, the first mounting groove 23 is spaced apart from two first protruding ribs 22. The first body 21 surrounds the first mounting groove 23. A first heat-fused portion 24 protrudes from the end face of the first groove sidewall 232 of the first mounting groove 23, i.e., protrudes from the first bottom surface 212 of the first body 21. The first connecting surface 242 of the first heat-fused portion 24 is connected to the first assembly end face M1 of the first body 21, and the inner surface 241 of the first heat-fused portion 24 is connected to the first groove sidewall 232 of the first mounting groove 23.

[0075] The first lower plastic 20 also has a first electrode through hole 25. The first electrode through hole 25 penetrates the first top surface 211 of the first body 21 and the first bottom wall 231 of the first mounting groove 23. The first electrode through hole 25 is used for the first electrode 60 to pass through. In this embodiment, the shape of the first electrode through hole 25 is approximately hexagonal. In some embodiments, the shape of the first electrode through hole 25 can also be circular, elliptical, etc., and this application does not impose strict limitations on this.

[0076] The first lower plastic 20 also includes a plurality of first limiting posts 26. The plurality of first limiting posts 26 are all located within the first mounting groove 23, and each of the first limiting posts 26 protrudes from the bottom wall 231 of the first mounting groove 23. The first limiting posts 26 are spaced apart at the periphery of the first pole post through hole 25, and the plurality of first limiting posts 26 are spaced apart from each other. Each first limiting post 26 is used to pass through a first limiting hole 414 of the first lower plastic 20, and the shape of the second limiting post 36 matches the shape of the first limiting hole 414. In this embodiment, the first limiting post 26 is cylindrical. The number of first limiting posts 26 is two.

[0077] As shown in Figure 4, the first lower plastic 20 also includes a first protrusion 27. The first protrusion 27 is located near the first connecting end face N1 of the first lower plastic 20. The first protrusion 27 protrudes from the first top surface 211 of the first body 21. Along the length direction of the first lower plastic 20, the first protrusion 27 is spaced apart from the first pole post through hole 25. The first protrusion 27 is used to be accommodated in the mounting groove 13 of the end cap 10. In this embodiment, the first protrusion 27 is an elongated protrusion.

[0078] Please refer to Figures 4 and 6 together. Figure 6 is a structural schematic diagram of the second lower plastic part of the end cap assembly shown in Figure 4 from another angle.

[0079] In this embodiment, the second lower plastic 30 is a long strip-shaped thin plate. The second lower plastic 30 includes a second body 31. The second body 31 includes a second top surface 311 and a second bottom surface 312. The second top surface 311 and the second bottom surface 312 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the second body 31. The second body 31 also includes a second mounting end surface M2 and a second connecting end surface N2. The second mounting end surface M2 and the second connecting end surface N2 are respectively the two opposite ends of the length direction (i.e., the Y-axis direction) of the second lower plastic 30.

[0080] As shown in Figure 6, the second lower plastic 30 also includes two second protruding ribs 32. Both second protruding ribs 32 protrude from the second bottom surface 312 of the second body 31. Along the width direction (i.e., the X-axis direction) of the second lower plastic 30, the two second protruding ribs 32 are located at opposite side edges of the second body 31. Both second protruding ribs 32 extend along the length direction of the second lower plastic 30. In this embodiment, the length of both second protruding ribs 32 is equal to the length of the second body 31 (allowing for certain manufacturing tolerances).

[0081] The second lower plastic 30 also includes a second boss 38 to accommodate the functional design needs of the first lower plastic 20. The second boss 38 protrudes from the second bottom surface 312 of the second body 31. Along the X-axis, the second boss 38 is spaced apart from two second ribs 32. Along the Y-axis, the second boss 38 is located at one end of the length direction of the second body 31. Specifically, the second boss 38 includes a second boss surface 381 and a second outer surface 382. The second boss surface 381 is away from the second body 31, and the orientation of the second boss surface 381 is the same as the orientation of the second bottom surface 312 of the second body 31. The second outer surface 382 connects the second boss surface 381 and the second assembly end face M2 of the second body 31. In this embodiment, the second boss 38 is approximately a rectangular protrusion.

[0082] The second lower plastic 30 also includes a second mounting groove 33. The second mounting groove 33 is recessed into the second boss surface 381 of the second boss 38 and is recessed towards the second body 31. The second mounting groove 33 is used to accommodate the second connecting portion 51 of the second pin 50, and the shape of the second mounting groove 33 matches the shape of the second connecting portion 51. The second boss surface 381 can be understood as the surface of the second lower plastic 30.

[0083] Specifically, the second mounting groove 33 includes a second groove bottom wall 331, a third groove side wall 332, and a fourth groove side wall 333. The orientation of the second groove bottom wall 331 is the same as the second bottom surface 312 of the second body 31. The third groove side wall 332 and the fourth groove side wall 333 are connected, and the third groove side wall 332 and the fourth groove side wall 333 together surround and connect to the second groove bottom wall 331. It can be understood that the third groove side wall 332 and the fourth groove side wall 333 together form the groove peripheral wall of the second mounting groove 33. The third groove side wall 332 is closer to the second assembly end face M2 of the second lower plastic 30 than the fourth groove side wall 333.

[0084] The second lower plastic 30 also includes a second heat-melt portion 34. The second heat-melt portion 34 protrudes from the second boss surface 381 of the second boss 38 and connects the second outer side surface 382 of the second boss 38 and the third groove sidewall 332. The second heat-melt portion 34 is used to connect with the protective film 400 via a heat-melt process. It can be understood that the second heat-melt portion 34 protrudes from the end face of the third groove sidewall 332 of the second mounting groove 33.

[0085] In this embodiment, the second heat-melting portion 34 is a strip-shaped protrusion with a triangular or right-angled trapezoidal cross-section. The second heat-melting portion 34 includes a clearance surface 341 and a second connecting surface 342. The clearance surface 341 and the second connecting surface 342 are disposed opposite to each other along the thickness direction of the second heat-melting portion 34. The second connecting surface 342 is connected to the second outer side surface 382 of the second boss 38. The clearance surface 341 is connected to the third groove sidewall 332 of the second mounting groove 33 and is disposed at an angle to the third groove sidewall 332. That is, the thickness of the second heat-melting portion 34 gradually decreases in the direction away from the third groove sidewall 332. In other embodiments, the second heat-melting portion 34 is connected to the second outer side surface 382 and is spaced apart from the third groove sidewall 332 of the second mounting groove 33. It is understandable that the thickness of the second heat-melting part 34 is less than or equal to the thickness of the third groove sidewall 332 of the second mounting groove 33.

[0086] In this embodiment, one dashed line in Figure 6 is the boundary line between the second heat-melting part 34 and the second boss 38, that is, the boundary line between the second connecting surface 342 of the second heat-melting part 34 and the second outer surface 382 of the second boss 38. The other dashed line is the boundary line between the second boss 38 and the second body 31, that is, the boundary line between the second outer surface 382 of the second boss 38 and the second mounting end face M2 of the second body 31.

[0087] In some embodiments, the second lower plastic 30 does not have a second boss 38, and the second mounting groove 33 is directly recessed into the second bottom surface 312 of the second body 31. Along the thickness direction (i.e., the Z-axis direction) of the second lower plastic 30, the second mounting groove 33 is formed by recessing from the second bottom surface 312 towards the second top surface 311. Along the width direction of the second lower plastic 30, the second mounting groove 33 is spaced apart from two second protruding ribs 32. The second body 31 surrounds the second mounting groove 33. The second heat-melting part 34 protrudes from the end face of the third groove sidewall 332 of the second mounting groove 33, i.e., protrudes from the second bottom surface 312 of the second body 31. The second connecting surface 342 of the second heat-melting part 34 is connected to the second assembly end face M2 of the second body 31. The clearance surface 341 of the second heat-melting part 34 is connected to the third groove sidewall 332 of the second mounting groove 33.

[0088] The second lower plastic 30 also has a second electrode through hole 35. The second electrode through hole 35 penetrates through the second top surface 311 of the second body 31 and the second bottom wall 331 of the second mounting groove 33. The second electrode through hole 35 is used for the second electrode 70 to pass through. In this embodiment, the shape of the second electrode through hole 35 is approximately hexagonal. In some embodiments, the shape of the second electrode through hole 35 can also be circular, elliptical, etc., and this application does not impose strict limitations on this.

[0089] The second lower plastic 30 also includes a plurality of second limiting posts 36. The plurality of second limiting posts 36 are all located within the second mounting groove 33, and each of the second limiting posts 36 protrudes from the bottom wall 331 of the second mounting groove 33. The second limiting posts 36 are spaced apart at the periphery of the second pole post through hole 35, and the plurality of second limiting posts 36 are spaced apart from each other. Each second limiting post 36 is used to pass through a second limiting hole 514 of the second pin 50, and the shape of the second limiting post 36 matches the shape of the second limiting hole 514. In this embodiment, the second limiting post 36 is cylindrical. The number of second limiting posts 36 is two.

[0090] As shown in Figure 4, the second lower plastic 30 also includes a second protrusion 37. The second protrusion 37 is located near the second connecting end face N2 of the second lower plastic 30. The second protrusion 37 protrudes from the second top surface 311 of the second body 31. Along the length of the second lower plastic 30, the second protrusion 37 is spaced apart from the second pole post through hole 35. The second protrusion 37 is used to be accommodated in the mounting groove 13 of the end cap 10. In this embodiment, the second protrusion 37 is an elongated protrusion.

[0091] Please refer to Figure 7, which is a cross-sectional structural diagram of the end cap assembly in the energy storage device shown in Figure 2. It should be noted that the dashed lines in Figure 7 are the boundary lines between the first heat-fused part 24 and the first boss 28, the boundary line between the first boss 28 and the first body 21, the boundary line between the first connecting part 41 and the first transition part 42, the boundary line between the second heat-fused part 34 and the second boss 38, the boundary line between the second boss 38 and the second body 31, and the boundary line between the second connecting part 51 and the second transition part 52.

[0092] In this embodiment, the first terminal 60, the second terminal 70, the first pin 40, the second pin 50, the first lower plastic 20, and the second lower plastic 30 are mounted together on the end cap 10 to form the end cap assembly 100.

[0093] The first lower plastic 20 and the second lower plastic 30 constitute the lower plastic. Specifically, the first connecting end face N1 of the first body 21 and the second connecting end face N2 of the second body 31 are spaced apart or connected. The first body 21 and the second body 31 form the lower plastic body. The lower plastic body includes a first mounting end face M1 and a second mounting end face M2. The orientation of the first top surface 211 of the first lower plastic 20 is the same as the orientation of the second top surface 311 of the second lower plastic 30, and the first top surface 211 and the second top surface 311 combine to form the top surface of the lower plastic. The orientation of the first bottom surface 212 of the first lower plastic 20 is the same as the orientation of the second bottom surface 312 of the second lower plastic 30, and the first bottom surface 212 and the second bottom surface 312 combine to form the bottom surface of the lower plastic. The first protrusion 27 of the first lower plastic 20 and the second protrusion 37 of the second lower plastic 30 combine to form the protrusion of the lower plastic.

[0094] Specifically, along the Y-axis, the orientation of the first mounting end face M1 of the lower plastic body is consistent with the orientation of the first end face 101 of the end cover 10, and the orientation of the second mounting end face M2 of the lower plastic body is consistent with the orientation of the second end face 102 of the end cover 10. The top surface of the lower plastic is connected to the lower surface 12 of the end cover 10. The protrusion of the lower plastic is accommodated in the mounting groove 13 of the end cover 10, so that the first lower plastic 20 and the second lower plastic 30 are confined on the end cover 10, preventing the first lower plastic 20 and the second lower plastic 30 from shifting relative to the end cover 10, thus affecting the reliability of the energy storage device 1000.

[0095] The first mounting groove 23 of the first lower plastic 20 and the second mounting groove 33 of the second lower plastic 30 are symmetrical about the central cross-section of the lower plastic in the width direction. Along the Y-axis, a first gap S1 is provided between the first mounting end face M1 of the first lower plastic 20 and the first end face 101 of the end cap 10, which reserves space for the protective film 400 to connect to the first lower plastic 20. A second gap S2 is provided between the second mounting end face M2 of the second lower plastic 30 and the second end face 102, which reserves space for the protective film 400 to connect to the second lower plastic 30. The first gap S1 is equal to the second gap S2. The sum of the lengths of the first lower plastic 20 and the second lower plastic 30 is less than the length of the end cap 10. The widths of both the first lower plastic 20 and the second lower plastic 30 are less than the width of the end cap 10.

[0096] The first pin 40 is mounted on the first lower plastic 20. The first connecting portion 41 of the first pin 40 is accommodated in the first mounting groove 23 of the first lower plastic 20, and the first outer connecting surface 412 of the first connecting portion 41 abuts against the first bottom wall 231 of the first mounting groove 23. Each first limiting post 26 of the first lower plastic 20 passes through a first limiting hole 414 of the first connecting portion 41 to limit the first pin 40 within the first lower plastic 20. The first through hole 413 of the first connecting portion 41 is coaxially arranged with the first pole post through hole 25 of the first lower plastic 20 to allow the first pole post 60 to pass through smoothly.

[0097] Along the Z-axis, the first adapter portion 42 of the first pin 40 extends away from the first lower plastic 20. The first adapter portion 42 is close to the first groove sidewall 232 of the first mounting groove 23. The first outer adapter surface 421 of the first adapter portion 42 is opposite to the first groove sidewall 232 and has a first gap Q1. The first adapter portion 42 and the first hot-melt portion 24 are spaced apart and opposite to each other along the length direction of the first lower plastic 20, and the first outer adapter surface 421 of the first adapter portion 42 faces the inner side surface 241 of the first hot-melt portion 24 and is spaced apart and opposite to the inner side surface 241. The orientation of the first outer adapter surface 421 of the first adapter portion 42 is consistent with the orientation of the first mounting end face M1 of the first lower plastic 20, and the first distance from the first outer adapter surface 421 to the first mounting end face M1 is D1. It can be understood that along the Y-axis, that is, the length direction of the lower plastic, the first outer adapter surface 421 has a first distance D1 from the first mounting end face M1.

[0098] The second pin 50 is mounted on the second lower plastic 30. The second connecting portion 51 of the second pin 50 is accommodated in the second mounting groove 33 of the second lower plastic 30, and the second outer connecting surface 512 of the second connecting portion 51 abuts against the second bottom wall 331 of the second mounting groove 33. Each second limiting post 36 of the second lower plastic 30 passes through a second limiting hole 514 of the second connecting portion 51 to limit the second pin 50 within the second lower plastic 30. The second through hole 513 of the second connecting portion 51 is coaxially arranged with the second pole post through hole 35 of the second lower plastic 30 to allow the second pole post 70 to pass through smoothly.

[0099] Along the Z-axis, the second adapter portion 52 of the second pin 50 extends away from the second lower plastic 30. The second adapter portion 52 is close to the third groove sidewall 332 of the second mounting groove 33. The second outer adapter surface 521 of the second adapter portion 52 faces the third groove sidewall 332 and has a second gap Q2. The second adapter portion 52 and the second hot-melt portion 34 are spaced apart and face each other along the length direction of the second lower plastic 30, and the second outer adapter surface 521 of the second adapter portion 52 faces the clearance surface 341 of the second hot-melt portion 34 and is spaced apart and face each other. The orientation of the second outer adapter surface 521 of the second adapter portion 52 is consistent with the orientation of the second mounting end face M2 of the second lower plastic 30, and the second distance from the second outer adapter surface 521 to the second mounting end face M2 is D2. It can be understood that along the Y-axis, that is, the length direction of the lower plastic, the second outer adapter surface 521 to the second mounting end face M2 has a second distance D2.

[0100] In this embodiment, the positions of the first pole post 60 and the second pole post 70 are symmetrical about the end cap assembly 100. The first mounting groove 23 of the first lower plastic 20 and the second mounting groove 33 of the second lower plastic 30 are symmetrical about the central cross section of the lower plastic in the width direction. The first gap Q1 between the first outer transition surface 421 of the first transition part 42 and the first groove sidewall 232 is greater than the second gap Q2 between the second outer transition surface 521 of the second transition part 52 and the third groove sidewall 332. When the thickness of the first electrode tab 220 is greater than the thickness of the second electrode tab 230, the first gap Q1 can meet the assembly of the first electrode tab 220, and the second gap Q2 can meet the assembly of the second electrode tab 230, thus solving the problem of difficult assembly of the first electrode tab 220.

[0101] Compared to existing technologies, the lower plastic, without altering the structure, only changes the lengths of the first connecting portion 41 of the first pin 40 and the second connecting portion 51 of the second pin 50. For example, the first length L1 of the first connecting portion 41 is reduced, and the second length L2 of the second connecting portion 51 is increased, with the second length L2 of the second connecting portion 51 being greater than the first length L1 of the first connecting portion 41. Since the first length L1 of the first connecting portion 41 of the first pin 40 is less than the second length L2 of the second connecting portion 51 of the second pin 50, the second distance D2 from the second outer transition surface 521 to the second assembly end surface M2 is less than the first distance D1 from the first outer transition surface 421 to the first assembly end surface M1. That is, the first pin 40 and the second pin 50 are offset towards one side of the second electrode post 70, which allows the cell 210 located between the first pin 40 and the second pin 50 to be offset towards one side of the second electrode post 70.

[0102] In addition, the clearance surface 341 of the second heat-melting part 34 is inclined and forms an angle with the side wall 332 of the third groove, so as to avoid the second connecting part 51 being too long and causing the second pin 50 to interfere with the second heat-melting part 34 of the second lower plastic 30, so that the heat-melting position of the second lower plastic 30 and the protective film 400 is not affected, and the processing difficulty when the protective film 400 and the second heat-melting part 34 are heat-melted is reduced.

[0103] The first electrode post 60 passes through the end cap 10, the first electrode post through hole 25 of the first lower plastic 20, and the first through hole 413 of the first connecting part 41, and is connected to the first connecting part 41, such as by laser welding, to achieve electrical conduction between the first electrode post 60 and the first pin 40. The first electrode post 60 is insulated and sealed from the end cap 10 by an insulating component (not shown in the figure), which not only prevents short circuits between the first electrode post 60 and the end cap 10, but also prevents the electrolyte inside the energy storage device 1000 from flowing out of the energy storage device 1000.

[0104] The second electrode post 70 passes through the second electrode post through hole 35 of the second lower plastic 30 and the second through hole 513 of the second connecting part 51, and is connected to the second connecting part 51, such as by laser welding, to achieve electrical conduction between the second electrode post 70 and the second pin 50. The second electrode post 70 is insulated and sealed from the end cover 10 by an insulating component (not shown in the figure), which not only prevents short circuits between the second electrode post 70 and the end cover 10, but also prevents the electrolyte inside the energy storage device 1000 from flowing out of the energy storage device 1000.

[0105] It should be noted that since the thickness of the first pin 40 is greater than the thickness of the second pin 50, the thickness of the first connecting portion 41 of the first pin 40 is greater than the thickness of the second connecting portion 51 of the second pin 50. Therefore, the height of the first boss 28 should be set to be greater than the height of the second boss 38.

[0106] Please refer to Figure 8, which is a cross-sectional structural diagram of the energy storage device shown in Figure 2. It should be noted that the dashed lines in Figure 8 are the dividing lines between the first connecting part 41 and the first transition part 42, as well as the dividing lines between the second connecting part 51 and the second transition part 52.

[0107] In this embodiment, the end cap assembly 100 is assembled with the electrode assembly 200. Specifically, along the Z-axis direction, the first connecting portion 41 of the first pin 40 and the second connecting portion 51 of the second pin 50 are spaced apart from the battery cell 210 to avoid short circuits caused by the first connecting portion 41 and the second connecting portion 51 connecting to the battery cell 210. Along the Y-axis direction, the battery cell 210 is located between the first transition portion 42 of the first pin 40 and the second transition portion 52 of the second pin 50. The first inner transition surface 422 of the first transition portion 42 faces the first side surface 210a of the battery cell 210. The first tab 220 extends from the first side surface 210a of the battery cell 210 to the side of the first transition portion 42 facing away from the battery cell 210, and is welded to the first connecting surface 242 of the first transition portion 42 to achieve the connection and electrical conduction between the first tab 220 and the first pin 40.

[0108] The second inner connecting surface 522 of the second adapter portion 52 faces the second side surface 210b of the cell 210. The second tab 230 extends from the second side surface 210b of the cell 210 to the side of the second adapter portion 52 opposite to the cell 210, and is welded to the second connecting surface 342 of the second adapter portion 52 to realize the connection and electrical conduction of the second tab 230 and the second pin 50.

[0109] It should be noted that the first tab 220 and the first pin 40 are made of the same material. The second tab 230 and the second pin 50 are made of the same material.

[0110] The protective film 400 wraps around the periphery and bottom of the electrode assembly 200 and is connected to the first heat-melt portion 24 and the second heat-melt portion 34 of the lower plastic through a heat-melt process. It can be understood that the protective film 400 forms a box structure with one open end and has an assembly port (not shown in the figure). The edge of the assembly port of the protective film 400 is connected to the edge of the lower plastic. Specifically, the edge of the assembly port of the protective film 400 is connected to the first outer surface 282 of the first boss 28, the second outer surface 382 of the second boss 38, the first connecting surface 242 of the first heat-melt portion 24, the second connecting surface 342 of the second heat-melt portion 34, the first rib 22, and the second rib 32, and is connected to the first heat-melt portion 24 and the second heat-melt portion 34 through a heat-melt process to fix the protective film 400 to the lower plastic.

[0111] The electrode assembly 200, the protective film 400, and the end cap assembly 100 are installed in the receiving cavity 302 of the housing 300. The protective film 400 insulates the electrode assembly 200 and the housing 300. The edge of the end cap 10 is connected to the edge of the opening 301 of the housing 300 by welding, gluing, or other means to seal the energy storage device 1000.

[0112] In related technologies, since the positions of the first electrode post 60 and the second electrode post 70 are symmetrical about the central cross-section of the lower plastic in the width direction, the first mounting groove 23 and the second mounting groove 33 are symmetrical about the central cross-section of the lower plastic in the width direction, and the first pin and the second pin are symmetrical about the central cross-section of the end cap assembly in the width direction, the distance from the first outer transition surface of the first pin to the first assembly end face of the first lower plastic is equal to the distance from the second outer transition surface of the second pin to the second assembly end face of the second lower plastic, the distance from the first outer transition surface to the groove side wall of the first mounting groove 23 is equal to the distance from the second outer transition surface to the groove side wall of the second mounting groove 33, and the distance from the second side surface 210b of the cell 210 to the housing 300 is equal to the distance from the first side surface 210a of the cell 210 to the housing 300. Because the thickness of the first tab 220 needs to be greater than the thickness of the second tab 230, when the electrode assembly 200 and the end cap assembly are assembled into the housing 300, the distance from the second tab 230 to the housing 300 is greater than the distance from the first tab 220 to the housing 300. If the distance from the second side surface 210b of the cell 210 to the housing 300 is just enough to accommodate the second tab 230, then assembling the first tab 220 becomes difficult. If the distance from the first side surface 210a of the cell 210 to the housing 300 is enough to accommodate the first tab 220, then the distance from the second tab 230 to the housing 300 is redundant, resulting in wasted space between the end cap assembly and the tabs. This prevents full utilization of the internal space of the energy storage device 1000 and reduces the energy density of the energy storage device 1000.

[0113] In this embodiment, the first pin 40 and the second pin 50 are asymmetrical about the center cross-section of the end cap assembly 100 in the width direction. Specifically, the length of the second connecting portion 51 of the second pin 50 is greater than the length of the first connecting portion 41 of the first pin 40, the first distance D1 from the first outer connecting surface 421 of the first adapter portion 42 to the first mounting end face M1 of the first lower plastic 20 is greater than the second distance D2 from the second outer connecting surface 521 of the second adapter portion 52 to the second mounting end face M2 of the second lower plastic 30, and the first gap Q1 between the first outer connecting surface 421 of the first adapter portion 42 and the first groove sidewall 232 is greater than the first gap Q1 between the second outer connecting surface 521 of the second adapter portion 52 and the third groove sidewall 332. The two gaps Q2 cause the battery cell 210 located between the first adapter 42 and the second adapter 52 to be offset toward one side of the second pole post 70. The distance K1 from the first side surface 210a of the battery cell 210 to the housing 300 is greater than the distance K2 from the second side surface 210b of the battery cell 210 to the housing 300. The gap between the first side surface 210a of the battery cell 210 and the housing 300 is sufficient to accommodate the thicker first pole tab 220. At the same time, the gap between the second side surface 210b of the battery cell 210 and the housing 300 is sufficient to accommodate the thinner second pole tab 230. Furthermore, the second electrode 230 has a first straight-line distance P1 to the housing 300, and the second electrode 230 has a second straight-line distance P2 to the housing 300. The first straight-line distance P1 is equal to the second straight-line distance P2. This not only allows the first electrode 220 and the second electrode 230 to be smoothly installed into the housing 300, but also avoids the electrode assembly 200 from shaking due to inconsistent distances from both sides of the electrode assembly 200 to the housing 300 in the length direction. This achieves effective utilization of the redundant space between the second electrode 230 and the housing 300, and improves the energy density of the energy storage device 1000.

[0114] In some embodiments, the first pin 40 and the second pin 50 have the same structure and size. The positions of the first pole post 60 and the second pole post 70 are asymmetrical about the central cross-section of the lower plastic in the width direction. The first mounting groove 23 and the second mounting groove 33 are also asymmetrical about the central cross-section of the lower plastic in the width direction. Specifically, the first pole post 60 is offset towards the second pole post 70, and the first mounting groove 23 is also offset towards the second mounting groove 33. Compared with the prior art, the holes through the end cap 10 and the lower plastic of the first pole post 60 are both offset, so that the first pin 40 is offset towards the second pole post 70. The offset distance is sufficient to meet the assembly of the first tab 220.

[0115] In some embodiments, the positions of the first electrode 60 and the second electrode 70 are asymmetrical about the central cross-section of the lower plastic through the width direction, while the first mounting groove 23 and the second mounting groove 33 are symmetrical about the central cross-section of the lower plastic through the width direction. The first pin 40 and the second pin 50 have the same structure, but the materials and dimensions of the first pin 40 and the second pin 50 are different, such as the thickness of the first pin 40 being greater than the thickness of the second pin 50, to ensure that the current carrying capacity of the first pin 40 and the second pin is consistent. The first connecting portion 41 of the first pin 40 is larger than the second connecting portion 51 of the second pin 50. Specifically, the first electrode 60 and the second electrode 70 are both offset along the positive direction of the Y-axis. Compared with the prior art, the holes through the end cap 10 and the lower plastic of the first electrode 60 are both offset, and the holes through the end cap 10 and the lower plastic of the second electrode 70 are both offset. Since the first pin 40 and the second pin 50 are connected to the first pole piece 60 and the second pole piece 70 respectively, the length of the first connecting part 41 is increased and the length of the second connecting part 51 is shortened. The length of the first connecting part 41 is greater than the length of the second connecting part 51, so that the distance between the first adapter part 42 and the housing 300 is greater than the distance between the second adapter part 52 and the housing 300, so as to satisfy the smooth assembly of the first tab 220 and the second tab 230.

[0116] The above are merely some embodiments and implementation methods of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An energy storage device, characterized in that, include: case; An electrode assembly is housed within the housing. The electrode assembly includes a battery cell, a first electrode tab, and a second electrode tab. The first electrode tab and the second electrode tab extend from both sides of the battery cell along its length. The thickness of the first electrode tab is greater than the thickness of the second electrode tab. The resistivity of the first electrode tab is greater than the resistivity of the second electrode tab. The cross-section of the first electrode tab is greater than the cross-section of the second electrode tab. and An end cap assembly is mounted on one end of the electrode assembly and seals the housing. The end cap assembly includes an end cap, a lower plastic body, a first pin, a second pin, a first electrode post, and a second electrode post. The lower plastic body includes a lower plastic body, which includes a first mounting end face and a second mounting end face. The first mounting end face and the second mounting end face are arranged opposite to each other along the length direction of the lower plastic body. The first pin includes a first connecting portion and a first adapter portion. The first adapter portion is connected to the first connecting portion and is disposed at an angle to the first connecting portion. The first connecting portion is mounted at one end of the lower plastic along its length. The first adapter portion extends away from the lower plastic and is connected to and electrically connected to the first electrode tab. The first adapter portion includes a first outer adapter surface, the orientation of which is the same as the orientation of the first mounting end face. Along the length of the end cap, the first outer adapter surface is at a first distance from the first mounting end face. The second pin includes a second adapter portion and a second connecting portion. The second adapter portion and the second connecting portion are connected and are arranged at an angle to each other. The second connecting portion is mounted on the other end of the lower plastic in the length direction. The second adapter portion extends away from the lower plastic and is connected to the second electrode and electrically connected. The second adapter portion includes a second outer adapter surface. The orientation of the second outer adapter surface is the same as the orientation of the second mounting end face. Along the length direction of the end cap, the second outer adapter surface has a second distance from the second mounting end face. The second distance is less than the first distance. The lower plastic and the end cap are stacked along the height direction of the end cap assembly. The first pole and the second pole are both inserted through the end cap and the lower plastic. The first pole is connected to the first connecting part and is electrically conductive, and the second pole is connected to the second connecting part and is electrically conductive.

2. The energy storage device according to claim 1, characterized in that, The lower plastic also includes a first mounting groove and a second mounting groove, both of which are recessed on the surface of the lower plastic facing away from the end cap. The first connecting part is accommodated in the first mounting groove, and the second connecting part is accommodated in the second mounting groove. Along the length direction of the end cap assembly, the first outer transition surface is opposite to the groove sidewall of the first mounting groove and has a first gap, and the second outer transition surface is opposite to the groove sidewall of the second mounting groove and has a second gap. The first gap is larger than the second gap.

3. The energy storage device according to claim 1, characterized in that, The lower plastic also includes a first mounting groove and a second mounting groove. The first mounting groove and the second mounting groove are both recessed on the surface of the lower plastic facing away from the end cap. The first mounting groove and the second mounting groove are symmetrical about the central cross section of the lower plastic in the width direction. The first pole and the second pole are symmetrically arranged about the center section of the lower plastic through the width direction, and the length of the second connecting part is greater than the length of the first connecting part.

4. The energy storage device according to claim 2 or 3, characterized in that, The lower plastic also includes a first hot melt part and a second hot melt part. The first hot melt part protrudes from the end face of the side wall of the first mounting groove, and the second hot melt part protrudes from the end face of the side wall of the second mounting groove. Along the length direction of the lower plastic, the first hot-melt portion and the first transition portion are spaced apart and opposite each other, and the second hot-melt portion and the second transition portion are spaced apart and opposite each other; The second hot-melt part further includes a clearance surface, which faces the second outer transition surface and is spaced apart from the second outer transition surface. The clearance surface is an inclined surface that is inclined away from the second transition part.

5. The energy storage device according to claim 4, characterized in that, The thickness of the first heat-melted part is less than or equal to the thickness of the sidewall of the first mounting groove, and the thickness of the second heat-melted part is less than or equal to the thickness of the sidewall of the second mounting groove.

6. The energy storage device according to any one of claims 1-3, characterized in that, Along the length direction of the end cap, there is a first gap between the first mounting end face and one end face of the end cap along the length direction, and there is a second gap between the second mounting end face and the other end face of the end cap along the length direction; The first spacing is equal to the second spacing.

7. The energy storage device according to claim 2 or 3, characterized in that, The lower plastic also includes a first boss and a second boss, both of which protrude from the surface of the lower plastic facing away from the end cap. The first boss includes a first outer side surface, which is connected to the first mounting end surface. The second boss includes a second outer side surface, which is connected to the second mounting end surface. The first mounting groove is recessed on the surface of the first boss, and the second mounting groove is recessed on the surface of the second boss.

8. The energy storage device according to claim 7, characterized in that, The height of the second boss is less than the height of the first boss.

9. The energy storage device according to claim 1, characterized in that, The lower plastic also includes a first lower plastic and a second lower plastic, the first lower plastic having the first mounting end face, and the second lower plastic having the second mounting end face; The first lower plastic and the second lower plastic are connected, and the first assembly end face faces away from the second assembly end face.

10. The energy storage device according to claim 1, characterized in that, Along the length of the battery cell, the distance from the first mounting end face to the housing is equal to the distance from the second mounting end face to the housing, and the distance from the first tab to the housing is equal to the distance from the second tab to the housing.

11. The energy storage device according to claim 1, characterized in that, The energy storage device includes a protective film that covers the bottom and periphery of the electrode assembly and is housed within the housing, with the protective film located between the electrode assembly and the housing. When the end cap assembly includes a first heat-fused part and a second heat-fused part, the protective film is connected to the first heat-fused part and the second heat-fused part.

12. An electrical appliance, characterized in that, It includes the energy storage device as described in any one of claims 1-11, wherein the energy storage device supplies power to the electrical equipment.

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