Connection, energy storage device, assembly method of energy storage device, and electric appliance

Abstract

This application provides a connector, an energy storage device, an assembly method for the energy storage device, and an electrical device, which are used to improve the assembly efficiency of the energy storage device and enhance product competitiveness. The connector includes a tab connection portion, a pole connection portion, and a flexible connection portion. The tab connection portion is used to electrically connect the tabs, the pole connection portion is used to electrically connect the poles, and the flexible connection portion connects the pole connection portion and the tab connection portion. The flexible connection portion includes multiple layers of first foil material, which are stacked along the thickness direction of the flexible connection portion. The flexibility of the flexible connection portion is greater than the flexibility of the pole connection portion and the tab connection portion.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a connector, an energy storage device, an assembly method for the energy storage device, and an electrical device. Background Technology

[0002] A rechargeable battery, also known as a secondary battery or accumulator, is a battery that can be recharged after discharge to reactivate its active materials and continue to be used. The recyclable nature of rechargeable batteries has made them a primary power source for electrical devices. As the demand for rechargeable batteries increases, higher requirements are being placed on their energy density, reliability, and cost. In the assembly process of rechargeable batteries, one side of the cell assembly's tab is welded to the connector before being installed in the casing, while the other side's tab is welded to the connector after installation. This complex assembly process results in low assembly efficiency and reduces the product competitiveness of rechargeable batteries. Summary of the Invention

[0003] This application provides a connector, an energy storage device, an assembly method for the energy storage device, and an electrical device, which are used to improve the assembly efficiency of the energy storage device and enhance product competitiveness.

[0004] In a first aspect, this application provides a connector for use in an energy storage device, including a tab connection portion, a pole connection portion, and a flexible connection portion. The tab connection portion is used to electrically connect tabs, the pole connection portion is used to electrically connect poles, and the flexible connection portion is connected between the pole connection portion and the tab connection portion. The flexible connection portion includes multiple layers of first foil material, which are stacked along the thickness direction of the flexible connection portion. The flexibility of the flexible connection portion is greater than the flexibility of the pole connection portion and the flexibility of the tab connection portion.

[0005] In one embodiment, the pole connection portion includes multiple layers of second foil material, which are stacked along the thickness direction of the pole connection portion, and each adjacent two layers of second foil material are connected to each other. The tab connection includes multiple layers of third foil. The multiple layers of third foil are stacked along the thickness direction of the tab connection, and each pair of adjacent layers of third foil are connected to each other. Each layer of the first foil is connected between a layer of the second foil and a layer of the third foil.

[0006] In one embodiment, the first foil, the second foil, and the third foil located on the same layer are integrally formed.

[0007] In one embodiment, the thickness of the pole post connector is greater than the thickness of the tab connector and the thickness of the flexible connector.

[0008] In one embodiment, the electrode connection portion further includes a conductive element, which is located on one side of the second foil and connected to the second foil along the thickness direction of the electrode connection portion.

[0009] In one embodiment, the conductive element is located on the side of the second foil facing the electrode post. The electrode post connection portion is provided with a first mounting hole and a second mounting hole. The first mounting hole penetrates the second foil along the thickness direction of the electrode post connection portion, and the second mounting hole penetrates the conductive element along the thickness direction of the electrode post connection portion. The second mounting hole includes a first hole portion and a second hole portion. The first hole portion communicates with the first mounting hole, and the second hole portion is located on the side of the first hole portion away from the first mounting hole and communicates with the first hole portion. Along the direction from the second hole portion to the first hole portion, the diameter of the second hole portion gradually decreases. Both the first mounting hole and the second mounting hole are used to mount the electrode post.

[0010] In one embodiment, the multilayer first foil material includes a first inner foil material and a first outer foil material, wherein the first inner foil material and the first outer foil material are disposed opposite to each other along the thickness direction of the flexible connection portion; The multilayer second foil includes a second inner foil and a second outer foil. Along the thickness direction of the pole post connection, the second inner foil and the second outer foil are arranged opposite to each other, and the second outer foil is located on the side of the first outer foil closer to the pole post. The multilayer third foil material includes a third inner foil material and a third outer foil material. Along the thickness direction of the tab connection portion, the third inner foil material and the third outer foil material are arranged opposite to each other. The first inner foil material is connected between the second inner foil material and the third inner foil material, and the first outer foil material is connected between the second outer foil material and the third outer foil material. When the connector is in a bent state, the second inner foil and the third inner foil are spaced apart and arranged opposite each other, and the second outer foil and the third outer foil are arranged opposite each other. Along the direction from the first inner foil to the first outer foil, the length of the multiple layers of the first foil gradually increases.

[0011] In one embodiment, the multiple layers of the first foil have the same length.

[0012] In one embodiment, the multiple layers of the second foil have the same length, and / or the multiple layers of the third foil have the same length.

[0013] In one embodiment, the pole connecting portion has a first surface, a second surface, a first circumferential side surface, and a second circumferential side surface. The second surface is located on the side of the first surface away from the pole and is disposed opposite to the first surface. The first circumferential side surface is connected between the first surface and the second surface. The second circumferential side surface is located on the side of the first circumferential side surface facing the flexible connecting portion and is disposed opposite to the first circumferential side surface, and is connected to the first surface. Along the direction from the first circumferential side surface to the second circumferential side surface, the distance between the second circumferential side surface and the second surface gradually decreases.

[0014] In one embodiment, the widths of the multiple layers of the first foil are the same.

[0015] In one embodiment, the thickness of each layer of the first foil is between 0.03 mm and 0.5 mm.

[0016] Secondly, this application provides an energy storage device, including a housing, a battery cell assembly, a spacer, a first end cap assembly, a second end cap assembly, a first connector, and a second connector. The housing has a receiving cavity, a first opening, and a second opening. The receiving cavity is located inside the housing. The first opening and the second opening are located on opposite sides of the receiving cavity and are both in communication with the receiving cavity. The battery cell assembly is received in the receiving cavity and includes a first tab and a second tab. The first spacer is installed in the receiving cavity and is located on one side of the battery cell assembly. The first end cap assembly and the second end cap assembly are both installed in the housing. The first end cap assembly closes the first opening, and the second end cap assembly closes the second opening. The first connector passes through the spacer. The first connector is the connector described above and is in a bent state. The tab connection portion is electrically connected to the first tab. The pole post connection portion is spaced apart from and opposite to the tab connection portion and is electrically connected to the pole post of the first end cap assembly. The second connector is electrically connected between the second tab and the pole post of the second end cap assembly.

[0017] In one embodiment, the pole connection portion includes multiple layers of second foil material, which are stacked along the thickness direction of the pole connection portion, and each adjacent two layers of second foil material are connected to each other. The tab connection includes multiple layers of third foil. The multiple layers of third foil are stacked along the thickness direction of the tab connection, and each pair of adjacent layers of third foil are connected to each other. Each layer of the first foil is connected between a layer of the second foil and a layer of the third foil.

[0018] In one embodiment, the first foil, the second foil, and the third foil located on the same layer are integrally formed.

[0019] In one embodiment, the thickness of the pole post connector is greater than the thickness of the tab connector and the thickness of the flexible connector.

[0020] In one embodiment, the electrode connection portion further includes a conductive element, which is located on one side of the second foil and connected to the second foil along the thickness direction of the electrode connection portion.

[0021] In one embodiment, the conductive element is located on the side of the second foil facing the electrode post. The electrode post connection portion is provided with a first mounting hole and a second mounting hole. The first mounting hole penetrates the second foil along the thickness direction of the electrode post connection portion, and the second mounting hole penetrates the conductive element along the thickness direction of the electrode post connection portion. The second mounting hole includes a first hole portion and a second hole portion. The first hole portion communicates with the first mounting hole, and the second hole portion is located on the side of the first hole portion away from the first mounting hole and communicates with the first hole portion. Along the direction from the second hole portion to the first hole portion, the diameter of the second hole portion gradually decreases. Both the first mounting hole and the second mounting hole are used to mount the electrode post.

[0022] In one embodiment, the multilayer first foil material includes a first inner foil material and a first outer foil material, wherein the first inner foil material and the first outer foil material are disposed opposite to each other along the thickness direction of the flexible connection portion; The multilayer second foil includes a second inner foil and a second outer foil. Along the thickness direction of the pole post connection, the second inner foil and the second outer foil are arranged opposite to each other, and the second outer foil is located on the side of the first outer foil closer to the pole post. The multilayer third foil material includes a third inner foil material and a third outer foil material. Along the thickness direction of the tab connection portion, the third inner foil material and the third outer foil material are arranged opposite to each other. The first inner foil material is connected between the second inner foil material and the third inner foil material, and the first outer foil material is connected between the second outer foil material and the third outer foil material. The second inner foil and the third inner foil are spaced apart and arranged opposite to each other, while the second outer foil and the third outer foil are arranged opposite to each other. The length of the multiple layers of the first foil gradually increases along the direction from the first inner foil to the first outer foil.

[0023] In one embodiment, the multiple layers of the first foil have the same length.

[0024] In one embodiment, the multiple layers of the second foil have the same length, and / or the multiple layers of the third foil have the same length.

[0025] In one embodiment, the pole connecting portion has a first surface, a second surface, a first circumferential side surface, and a second circumferential side surface. The second surface is located on the side of the first surface away from the pole and is disposed opposite to the first surface. The first circumferential side surface is connected between the first surface and the second surface. The second circumferential side surface is located on the side of the first circumferential side surface facing the flexible connecting portion and is disposed opposite to the first circumferential side surface, and is connected to the first surface. Along the direction from the first circumferential side surface to the second circumferential side surface, the distance between the second circumferential side surface and the second surface gradually decreases.

[0026] In one embodiment, the widths of the multiple layers of the first foil are the same.

[0027] In one embodiment, the thickness of each layer of the first foil is between 0.03 mm and 0.5 mm.

[0028] Thirdly, this application provides an electrical device, including the energy storage device described above, which supplies power to the electrical device.

[0029] Fourthly, this application provides a method for assembling an energy storage device, comprising: The system provides a housing, a cell assembly, a spacer, a first connector, a second connector, a first end cap assembly, and a second end cap assembly. The housing includes a receiving cavity, a first opening, and a second opening. The receiving cavity is located inside the housing. The first opening and the second opening are located on opposite sides of the receiving cavity and are both in communication with the receiving cavity. The cell assembly includes a first tab and a second tab. The first connector is any of the connectors described above. Both the first end cap assembly and the second end cap assembly include a terminal post. The second connector is electrically connected to the pole of the second end cap assembly; Electrically connect the second connector to the second electrode ear; The electrode connecting portion of the first connector is electrically connected to the first electrode; Pass the first connector through the spacer ring; The cell assembly, the spacer, the first connector, and the second connector are assembled into the receiving cavity; The second end cap assembly is installed on the housing, wherein the second end cap assembly closes the second opening; The pole connection portion of the first connector is electrically connected to the pole of the first end cap assembly; The first end cap assembly is installed on the housing, wherein the first end cap assembly closes the first opening.

[0030] In the energy storage device described in this application, the flexible connection portion of the connector allows the connector itself to bend, enabling the first and second tabs of the battery cell assembly to be simultaneously welded to the first and second connectors respectively before being installed in the casing. Compared to an assembly method where one tab is connected to an adapter plate before installation and the other tab is welded to the adapter plate after installation, this not only simplifies the assembly process of the energy storage device, improves its assembly efficiency, and enhances product competitiveness, but also shortens the tab length, saving production costs. Furthermore, the multi-layer design of the flexible connection portion can improve the current-carrying capacity of the connector due to the skin effect of the current, thus contributing to improved electrical performance of the energy storage device. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0032] Figure 1a This is a schematic diagram of the structure of the first energy storage system according to an embodiment of this application; Figure 1b This is a schematic diagram of the structure of a second type of energy storage system according to an embodiment of this application; Figure 2 This is a schematic diagram of the energy storage device provided in this application; Figure 3 yes Figure 2 The diagram shows the exploded structure of the energy storage device. Figure 4 yes Figure 2 A schematic diagram of a partial cross-sectional structure of the energy storage device shown after it has been cut open at point II. Figure 5 yes Figure 3 A schematic diagram of the spacer structure in the energy storage device shown; Figure 6 yes Figure 3 A schematic diagram of the structure of the first connector in the energy storage device shown; Figure 7 yes Figure 6 The diagram shows the first connector in its flattened state. Figure 8 yes Figure 6 A schematic diagram of the cross-sectional structure of the first connector after it has been cut along point II-II; Figure 9 yes Figure 7 A schematic diagram of the cross-sectional structure of the first connector after it has been cut along point III-III; Figure 10 yes Figure 2 A schematic diagram of a partial cross-sectional structure of the energy storage device shown after it has been cut open at point II. Figure 11 yes Figure 3 A schematic diagram of the structure of the second connector in the energy storage device shown; Figure 12 yes Figure 3 A schematic diagram of the structure of the first end cap assembly in the energy storage device shown; Figure 13 yes Figure 12 The diagram shows a cross-sectional view of the first end cap assembly after it has been cut along line IV-IV. Figure 14 This is a process flow diagram of the assembly method of the energy storage device provided in this application; Figure 15 yes Figure 14 The structural diagram of step S8 in the process flow diagram shown.

[0033] The names corresponding to the labels in the figure are: Energy storage system 1, high-voltage cable 2, first power conversion device 3, second power conversion device 4, energy storage device 5, photovoltaic-energy storage-charging station 6, automobile 7, housing 10, cell assembly 20, spacer 30, connector 40, Mylar sheet 50, air guide plate 60, end cap assembly 70, insulating film 80, top patch 90, receiving cavity 101, opening 102, first opening 102a, cell body 21, first electrode 22, second electrode 24, sub-cell assembly 23, sub-cell body 231, first sub-electrode 232, second sub-electrode 233, spacer 30, first connector 40a, second connector 40b, first end cap assembly 70a, second end cap assembly 70b, first top patch 90a, second top patch 90b, bottom plate 31, side plate 3 2. Through hole 311, tab connection part 41, pole post connection part 42, flexible connection part 43, first foil 431, first inner foil 431a, first outer foil 431b, third foil 411, third inner foil 411a, third outer foil 411b, first surface 425, second surface 426, first peripheral side 427, first mounting hole 421, second mounting hole 424, second peripheral side 428, second foil 422, conductive element 423, second inner foil 422a, second outer foil 422b, first hole 4241, second hole 4242, conductive foil 44, mounting hole 401, end cap 71, protective sheet 72, lower insulating element 73, upper insulating element 74, pole post 75, pressure block 76 and sealing ring 77. Detailed Implementation

[0034] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0035] 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 for future applications. Currently, 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 solar, wind, and hydropower. However, wind and solar power are generally characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak demand periods, and excessive power 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. This involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, this energy can be converted back into electrical energy and released. Simply put, energy storage is like a large "power bank," storing electrical energy when solar and wind power are abundant and releasing the stored electricity when needed.

[0036] Taking electrochemical energy storage as an example, this solution provides an energy storage device for use in energy storage systems. The energy storage device is equipped with a set of chemical batteries, which mainly use the chemical elements in the batteries as energy storage media. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage media. 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 electricity is released for use, or transferred to places with a shortage of electricity for use.

[0037] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. The corresponding types of energy storage devices include: (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can help renewable energy power generation meet grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power regulation power source on the power supply side, energy storage power stations can achieve load matching of power in time and space, enhance the absorption capacity of renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy power generation, and are of great significance in power grid system backup, alleviating peak load power supply pressure and peak regulation and frequency regulation. (2) Energy storage containers applied on the grid side mainly function as peak shaving, frequency regulation and relief of grid congestion. In terms of peak shaving, they can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak electricity load period, thereby achieving a balance between power production and consumption. (3) Small energy storage cabinets applied to the electricity consumption side mainly function as self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improvement of power supply reliability. Depending on the application scenario, electricity consumption side energy storage can be divided into industrial and commercial energy storage cabinets, household energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaics. Industrial and commercial users can use energy storage for peak-valley price arbitrage and capacity cost management. In the electricity market implementing peak-valley pricing, by charging the energy storage system when the electricity price is low and discharging the energy storage system when the electricity price is high, peak-valley price arbitrage can be achieved, reducing electricity costs. In addition, industrial enterprises subject to two-part tariffs can use energy storage systems to store energy during off-peak hours and discharge during peak loads, thereby reducing peak power and the maximum demand declared, achieving the goal of reducing capacity costs. Household photovoltaics with energy storage can improve the level of self-consumption of electricity. Due to high electricity prices and poor power supply stability, the demand for household photovoltaic installations is driven. Given that photovoltaic power generation occurs during the day, while user load is generally higher at night, configuring energy storage can better utilize photovoltaic power, improve self-consumption levels, and reduce electricity costs. Furthermore, energy storage is needed in areas such as communication base stations and data centers for backup power.

[0038] In some embodiments, see Figure 1a , Figure 1a This is a schematic diagram of the structure of the first type of energy storage system 1 according to an embodiment of this application, and this application Figure 1a The embodiments are illustrated using a shared energy storage scenario on the generation / distribution side as an example. The energy storage device 5 of this application is not limited to the energy storage scenario on the generation / distribution side.

[0039] This application provides a first type of energy storage system 1, which includes: a high-voltage cable 2, a first power conversion device 3, a second power conversion device 4, and an energy storage device 5 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4 can be a wind power conversion device. Since the electricity generated by wind power conversion is volatile, random, and intermittent, the unstable electricity output by the wind power conversion device can be stored in the energy storage device 5 through grid connection. The energy storage device 5 is connected to the high-voltage cable 2 and outputs smooth electricity to supply the power consumption side of the distribution network, realizing peak shaving and frequency regulation, and stable grid operation; or, the wind power conversion device initially... Finally, it connects to high-voltage cable 2. Under normal power generation conditions, the power output of the wind power conversion device is supplied to the power consumption side of the distribution network through the high-voltage cable. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in energy storage device 5 to reduce wind and solar curtailment rates and improve the problem of new energy power generation consumption. When the power load is high, the power grid issues an instruction to transmit the power stored in energy storage device 5 together with high-voltage cable 2 in grid-connected mode to supply power to the power consumption side. This provides the power grid with various services such as peak shaving, frequency regulation, and backup, giving full play to the peak shaving role of the power grid, promoting peak shaving and valley filling, and alleviating the power supply pressure of the power grid.

[0040] In some embodiments on the distribution network side, the first power conversion device 3 can be a photovoltaic power conversion device, and the energy storage device 5 is connected to the high-voltage cable 2 and installed downstream of the high-voltage cable 2 between the user load. The power output of the photovoltaic power conversion device is stored in the energy storage device 5, which can respond in a timely manner to act as a backup power source when the power grid / distribution network fails; or, it can provide power supply support to alleviate line blockage when the high-voltage cable 2 transmission line is blocked, and to delay the economic pressure caused by the expansion of the power grid / distribution capacity when the power grid is planned to be expanded.

[0041] Optionally, the first power conversion device may include, but is not limited to, a wind power conversion device, and the second power conversion device may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 3 and the second power conversion device 4 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy, and mechanical energy into electrical energy.

[0042] Optionally, the energy storage device 5 may include, but is not limited to, energy storage applications such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power supply systems, and may also be applied in multiple fields such as data centers, military equipment, aerospace, charging piles, and electric vehicles.

[0043] Optionally, the energy storage device 5 may include, but is not limited to, a single battery cell, or a battery module, battery pack, battery cluster, power bank, energy storage cabinet / container, or other battery integrated system composed of single batteries. The actual application form of the energy storage device 5 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 5. This application embodiment only uses a multi-cell battery as an example for illustration.

[0044] In some embodiments, see Figure 1b , Figure 1b This is a schematic diagram of the structure of the second type of energy storage system 1 according to an embodiment of this application, and this application Figure 1b The embodiments are illustrated using industrial and commercial energy storage scenarios as an example. The energy storage device 5 of this application is not limited to energy storage scenarios on the power generation / distribution side.

[0045] This application provides a second type of energy storage system 1, which includes: an energy storage device 5, a high-voltage cable 2, a factory equipped with a first power conversion device 3, a photovoltaic-energy storage-charging station 6, and a vehicle 7. In some embodiments of industrial and commercial scenarios, the first power conversion device 3 can be a photovoltaic panel, which converts solar energy into electrical energy and stores it in the energy storage device 5 in the factory. In the event of a power grid failure, the energy storage device 5 provides power to ensure the safe and stable operation of the factory without interruption. Alternatively, when the factory's power load is high, the power grid issues an instruction to transmit the electricity stored in the energy storage device 5 in conjunction with the high-voltage cable 2 in a grid-connected mode to supply the factory with electricity, providing various services such as peak shaving / frequency regulation and backup for the power grid operation. In addition, the first power conversion device 3 can also convert solar energy into electrical energy and store it in the energy storage device 5 of the photovoltaic-energy storage-charging station 6, directly charging the vehicle 7 through the photovoltaic-energy storage-charging station 6, which is fast and convenient.

[0046] Optionally, the first power conversion device 3 may include, but is not limited to, photovoltaic panels and wind power conversion devices. The first power conversion device 3 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0047] Please see Figures 2 to 4 , Figure 2 This is a schematic diagram of the structure of the energy storage device 5 provided in this application. Figure 3 yes Figure 2 The exploded structure diagram of the energy storage device 5 shown is shown. Figure 4 yes Figure 2 The diagram shows a partial cross-sectional view of the energy storage device 5 after it has been cut along point II. "Cut along point II" means cutting along the plane containing line II; similar descriptions in the following text can be understood in the same way.

[0048] This application provides an energy storage device 5, which may include, but is not limited to, a single battery cell, a battery module, a battery pack, or a battery system. Optionally, when the energy storage device 5 is a single battery cell, it may be, but is not limited to, at least one of cylindrical, prismatic, prismatic, or other shaped batteries. The single battery cell may be a rechargeable battery, meaning a battery that can be reactivated by charging after discharge to continue its use. The single battery cell may be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, or lead-acid battery, etc., and this application does not specifically limit its application. It should be noted that the actual application form of the energy storage device 5 provided in this application may be, but is not limited to, the listed products, and may also be other application forms. This application does not strictly limit the application form of the energy storage device 5. This application uses a prismatic battery as an example for illustration.

[0049] The energy storage device 5 includes a housing 10, a battery cell assembly 20, a spacer 30, a connector 40, a Mylar sheet 50, a gas guide plate 60, an end cap assembly 70, an insulating film 80, and a top patch 90. The housing 10 has a receiving cavity 101 and an opening 102. The receiving cavity 101 is located inside the housing 10 and contains electrolyte. The opening 102 is located on one side of the receiving cavity 101 and communicates with it. There are two openings 102, namely a first opening 102a and a second opening (not shown). Along the length of the energy storage device 5, the first opening 102a and the second opening are arranged opposite to each other and both communicate with the receiving cavity 101. For example, the housing 10 may be made of aluminum; for instance, the housing 10 may be an aluminum shell.

[0050] The battery cell assembly 20 is housed in the receiving cavity 101. The battery cell assembly 20 can be immersed in electrolyte. The battery cell assembly 20 includes a battery cell body 21, a first electrode 22, and a second electrode 24 (e.g., ...). Figure 10 (As shown). Along the length of the energy storage device 5, the first tab 22 and the second tab 24 are respectively connected to opposite sides of the cell body 21. There are two of each type of tab, with two first tabs 22 spaced apart and two second tabs 24 spaced apart. One first tab 22 and one second tab 24 serve as the positive tab, and the other first tab 22 and the other second tab 24 serve as the negative tab.

[0051] In this embodiment, the battery cell assembly 20 may include two sub-cell assemblies 23, which are arranged along the thickness direction of the energy storage device 5. Each sub-cell assembly 23 includes a sub-cell body 231, a first sub-tab 232, and a second sub-tab 233 (e.g., ...). Figure 10As shown), the first sub-tab 232 and the second sub-tab 233 are respectively connected to opposite sides of the sub-cell body 231. The sub-cell bodies 231 of the two sub-cell assemblies 23 form the cell body 21, the first sub-tabs 232 of the two sub-cell assemblies 23 form the first tab 22 by welding, and the second sub-tabs 233 of the two sub-cell assemblies 23 form the second tab 24.

[0052] A spacer ring 30 is installed in the receiving cavity 101. Along the length of the energy storage device 5, the spacer ring 30 is located on one side of the cell assembly 20. The spacer ring 30 is close to the first opening 102a. Connectors 40 are electrically connected to the cell assembly 20. There are four connectors 40: two first connectors 40a and two second connectors 40b. Both first connectors 40a pass through the spacer ring 30 and are electrically connected to the two first tabs 22, respectively. The two second connectors 40b are electrically connected to the two second tabs 24, respectively. Mylar plates 50 and air guide plates 60 are both located in the receiving cavity 101 and between the cell assembly 20 and the housing 10. There are two Mylar plates 50 and two air guide plates 60. Along the thickness direction of the energy storage device 5, the two Mylar plates 50 are located on opposite sides of the cell body 21. Along the width direction of the energy storage device 5, the two air guide plates 60 are located on opposite sides of the cell body 21. End cap assemblies 70 are mounted on the housing 10, closing the opening 102a and electrically connected to the connectors 40. There are two end cap assemblies 70: a first end cap assembly 70a and a second end cap assembly 70b. The first end cap assembly 70a closes the first opening 102a and is electrically connected to two first connectors 40a. The terminals of the first end cap assembly 70a are electrically connected to the two first connectors 40a. The second end cap assembly 70b closes the second opening and is electrically connected to two second connectors 40b. The terminals of the second end cap assembly 70b are electrically connected to the two second connectors 40b. An insulating film 80 covers the outer peripheral surface of the housing 10. Top patches 90 are disposed on the surface of the end cap assembly 70 facing away from the housing 10. There are two top patches 90: a first top patch 90a and a second top patch 90b. The first top patch 90a is disposed on the surface of the first end cap assembly 70a facing away from the housing 10. The second top patch 90b is disposed on the surface of the second end cap assembly 70b facing away from the housing 10.

[0053] Please see Figure 5 , Figure 5 yes Figure 3 A schematic diagram of the structure of the spacer ring 30 in the energy storage device 5 shown.

[0054] The spacer ring 30 includes a base plate portion 31 and a side plate portion 32. The side plate portion 32 is connected to the base plate portion 31 and is disposed around the base plate portion 31. In this embodiment, the base plate portion 31 is provided with a through hole 311, which penetrates the base plate portion 31 along the thickness direction of the base plate portion 31. There are two through holes 311, which are spaced apart.

[0055] Please refer to the following: Figure 4 , Figure 6 and Figure 7 , Figure 6 yes Figure 3 The diagram shows the structure of the first connector 40a in the energy storage device 5. Figure 7 yes Figure 6 The diagram shows the structure of the first connector 40a in its flattened state. Figure 6 The first connector 40a shown is in a bent state.

[0056] The first connector 40a includes a tab connection portion 41, a post connection portion 42, and a flexible connection portion 43. The tab connection portion 41 is electrically connected to the first tab 22. The post connection portion 42 passes through the through hole 311 of the spacer 30 and is electrically connected to the post of the first end cap assembly 70a. The flexible connection portion 43 connects the tab connection portion 41 and the post connection portion 42.

[0057] Please refer to the following: Figure 8 and Figure 9 , Figure 8 yes Figure 6 The diagram shows a cross-sectional view of the first connector 40a after it has been cut along line II-II. Figure 9 yes Figure 7 The diagram shows a cross-sectional view of the first connector 40a after it is cut along point III-III.

[0058] The flexibility of the flexible connection portion 43 is greater than that of the tab connection portion 41 and the pole connection portion 42. The flexible connection portion 43 includes multiple layers of first foil 431, which are stacked along the thickness direction of the flexible connection portion 43. For example, the material of the first foil 431 can be the same as that of the first tab 22. The thickness of the first foil 431 is between 0.03 mm and 0.5 mm to ensure the flexibility and current-carrying capacity of the flexible connection portion 43. For example, the thickness of the first foil 431 is 0.1 mm. It should be noted that users can adjust the number of layers of the first foil 431 and the total thickness of the flexible connection portion according to current-carrying requirements; this application does not impose specific limitations in this regard.

[0059] The multilayer first foil 431 includes a first inner foil 431a and a first outer foil 431b. Along the thickness direction of the flexible connection, the first inner foil 431a and the first outer foil 431b are arranged opposite to each other. When the first connector 40a is in a bent state, the flexible connection 43 is also in a bent state, and the first inner foil 431a is located inside the first outer foil 431b. Specifically, the first inner foil 431a is the innermost first foil 431 in the multilayer first foil 431, and the first outer foil 431b is the outermost first foil 431 in the multilayer first foil 431.

[0060] Along the direction from the first inner foil 431a to the first outer foil 431b, the length of the multiple layers of first foil 431 gradually increases. In this embodiment, the length of the first outer foil 431b is greater than the length of the first inner foil 431a, so that the flexible connection 43 can be bent, avoiding wrinkles in the first inner foil 431a, which would cause a large rebound force and result in the foil popping out after being inserted into the casing, thus helping to ensure the reliability of the energy storage device 5. In this embodiment, the width of the multiple layers of first foil 431 is the same, and the width of the first outer foil 431b can be equal to the width of the first inner foil 431a. In other embodiments, the length of the first outer foil 431b can be equal to the length of the first inner foil 431a, in which case the length of the multiple layers of first foil 431 can be the same, reducing the manufacturing difficulty of the first connector 40a and improving its manufacturability.

[0061] The tab connection portion 41 includes multiple layers of third foil 411. Along the thickness direction of the tab connection portion 41, the multiple layers of third foil 411 are stacked sequentially, with each adjacent pair of third foil layers 411 connected to each other, and each third foil layer 411 connected to a first foil layer 431. Exemplarily, each adjacent pair of third foil layers 411 can be connected to each other by welding, riveting, or other methods. The multiple layers of third foil 411 include a third inner foil layer 411a and a third outer foil layer 411b. Along the thickness direction of the tab connection portion 41, the third inner foil layer 411a and the third outer foil layer 411b are arranged opposite to each other. Exemplarily, the multiple layers of third foil 411 have the same length and the same width. In some other embodiments, the lengths of the multiple layers of third foil 411 may be different, and / or, the widths of the multiple layers of third foil 411 may be different.

[0062] The thickness of the pole post connection portion 42 is greater than the thickness of the tab connection portion 41 and the thickness of the flexible connection portion 43 to improve the current-carrying capacity of the first connector 40a. The pole post connection portion 42 has a first surface 425, a second surface 426, a first peripheral side surface 427, and a second peripheral side surface 428. The second surface 426 is located on the side of the first surface 425 facing away from the pole post 75 and is disposed opposite to the first surface 425. The first peripheral side surface 427 is connected between the first surface 425 and the second surface 426. The second peripheral side surface 428 is located on the side of the first peripheral side surface 427 facing the flexible connection portion 43 and is disposed opposite to the first peripheral side surface 427. Along the direction from the first peripheral side surface 427 to the second peripheral side surface 428, the distance between the second peripheral side surface 428 and the second surface 426 gradually decreases, which can prevent the pole post connection portion 42 from interfering with the lower insulating member or explosion-proof valve of the first end cap assembly 70a. For example, the second side 428 is a slope, and at this time, the pole post connection 42 is roughly trapezoidal.

[0063] In this embodiment, the electrode connector 42 includes multiple layers of second foil 422 and a conductive element 423. The multiple layers of second foil 422 are stacked along the thickness direction of the electrode connector 42, with each adjacent pair of second foil layers 422 interconnected. For example, each adjacent pair of second foil layers 422 can be interconnected by welding, riveting, or other methods. Each second foil layer 422 is connected to a first foil layer 431. That is, each first foil layer 431 is connected between a second foil layer 422 and a third foil layer 411. For example, the first foil layer 431, the second foil layer 422, and the third foil layer 411 located in the same layer are integrally formed to reduce the manufacturing cost of the connector 40. In this embodiment, the multiple layers of second foil 422 have the same length and the same width. In other embodiments, the lengths of the multiple layers of second foil 422 may be different, and / or the widths of the multiple layers of second foil 422 may be different.

[0064] The multilayer second foil 422 includes a second inner foil 422a and a second outer foil 422b. Along the thickness direction of the tab connection 41, the second inner foil 422a and the second outer foil 422b are disposed opposite to each other. The second outer foil 422b is located on the side of the second inner foil 422a near the pole of the first end cap assembly 70. The second inner foil 422a has a portion of a first peripheral side surface 427. The second outer foil 422b has a second surface 426 and a portion of the first peripheral side surface 427. The first inner foil 431a is connected between the second inner foil 422a and the third inner foil 411a, and the first outer foil 431b is connected between the second outer foil 422b and the third outer foil 411b. Figure 8As shown, when the connector 40 is in a bent state, the second inner foil 422a and the third inner foil 411a are spaced apart and arranged opposite to each other, while the second outer foil 422b and the third outer foil 411b are arranged opposite to each other.

[0065] Along the thickness direction of the electrode connection portion 42, the conductive element 423 is located on one side of the second foil 422 and is interconnected with the second foil 422 to increase the current-carrying capacity between the first connector 40a and the electrode of the first end cap assembly 70. Specifically, along the thickness direction of the electrode connection portion 42, the conductive element 423 is located on the side of the multilayer second foil 422 facing the electrode of the first end cap assembly 70a. The conductive element 423 is located on the side of the second outer foil 422b away from the second inner foil 422a, and has a first surface 425, a portion of a first peripheral side surface 427, and a second peripheral side surface 428. In some other embodiments, the conductive element 423 may also be located between two adjacent layers of second foil 422, which is not specifically limited in this application. Exemplarily, the conductive element 423 and the second foil 422 may also be interconnected by welding (e.g., ultrasonic welding), riveting, or other methods. It should be noted that when the first connector 40a is used as a positive electrode connector, the conductive element 423 can be made of aluminum; when the first connector 40a is used as a negative electrode connector, the conductive element 423 can be made of copper.

[0066] In this embodiment, the electrode connection portion 42 is provided with a first mounting hole 421 and a second mounting hole 424. Both the first mounting hole 421 and the second mounting hole 424 are used to mount the electrode of the first end cap assembly 70a. The first mounting hole 421 penetrates multiple layers of second foil 422 along the thickness direction of the electrode connection portion 42, and the second mounting hole 424 penetrates the conductive element 423 along the thickness direction of the electrode connection portion 42. The second mounting hole 424 includes a first hole portion 4241 and a second hole portion 4242. The first hole portion 4241 communicates with the first mounting hole 421, and the second hole portion 4242 is located on the side of the first hole portion 4241 opposite to the first mounting hole 421, and communicates with the first hole portion 4241. The diameter of the second hole portion 4242 gradually decreases along the direction from the second hole portion 4242 to the first hole portion 4241. For example, the wall surface of the second hole portion 4242 is a chamfered surface. The hole wall of the second hole 4242 can guide the pole of the first end cap assembly 70 to ensure the assembly efficiency between the first connector 40a and the pole of the first end cap assembly 70.

[0067] In one embodiment, the first connector 40a includes multiple layers of conductive foil 44 and conductive elements 423, with the multiple layers of conductive foil 44 stacked sequentially along the thickness direction of the first connector 40a. Each layer of conductive foil 44 includes a first foil 431, a second foil 422, and a third foil 411. The second foil 422 and conductive elements 423 of the multiple layers of conductive foil 44 can be fixed by welding, riveting, or other processes to form a terminal connection 42, and the third foil 411 of the multiple layers of conductive foil 44 can be fixed by welding, riveting, or other processes to form a tab connection 41. In this case, the multiple layers of first foil 431 in the flexible connection 43 still retain the multilayer structural characteristics, which can improve the current-carrying capacity of the connector due to the skin effect of the current, thus helping to improve the electrical performance of the energy storage device. It should be noted that the skin effect of current refers to the phenomenon that when current passes through a conductor, the current density tends to concentrate near the surface of the conductor, and the current density inside the conductor decreases exponentially with increasing depth.

[0068] Please see Figure 10 and Figure 11 , Figure 10 yes Figure 2 The diagram shows a partial cross-sectional view of the energy storage device 5 after it has been cut along point II. Figure 11 yes Figure 3 A schematic diagram of the structure of the second connector 40b in the energy storage device 5 shown.

[0069] In this embodiment, the structure of the second connector 40b differs from that of the first connector 40a. For example, the second connector 40b is sheet-shaped. The second connector 40b has a mounting hole 401 that extends through the second connector 40b along its thickness direction and is used to mount the pole post of the second end cap assembly 70b. The two second sub-pole tabs 233 of the second pole tab 24 are electrically connected to the second connector 40b and are respectively connected to opposite sides of the mounting hole 401, and are spaced apart from the mounting hole 401. In other embodiments, the structure of the second connector 40b may be the same as that of the first connector 40a. The relevant structure of the second connector 40b can be referred to the relevant description of the first connector 40a, and this application does not impose specific limitations on it.

[0070] In the energy storage device 5 shown in this embodiment, the flexible connecting portion 43 of the first connector 40a allows the first connector 40a to bend, enabling the first tab 22 and the second tab 24 of the battery cell assembly 20 to be simultaneously welded to the first connector 40a and the second connector 40b before being inserted into the housing. Compared to the assembly method where one tab is connected to the adapter plate before insertion into the housing, and the other tab is welded to the adapter plate after insertion into the housing, this not only simplifies the assembly process of the energy storage device 5, improves its assembly efficiency, and enhances its competitiveness, but also shortens the tab length, saving production costs. Furthermore, the multi-layer design of the flexible connecting portion 43 can improve the current-carrying capacity of the first connector 40a due to the skin effect of the current, thus improving the electrical performance of the energy storage device 5. In addition, compared to existing U-shaped or T-shaped three-dimensional adapter plates, the first connector 40a shown in this embodiment can reduce the space it occupies within the housing 10, saving internal space and contributing to increasing the energy density of the energy storage device 5.

[0071] Please refer to the following: Figure 12 and Figure 13 , Figure 12 yes Figure 3 A schematic diagram of the structure of the first end cap assembly 70a in the energy storage device 5 is shown. Figure 13 yes Figure 12 The diagram shows a cross-sectional view of the first end cap assembly 70a after it is cut along line IV-IV.

[0072] The first end cap assembly 70a includes an end cap 71, an explosion-proof valve (not shown), a protective plate 72, a lower insulating member 73, an upper insulating member 74, a pole post 75, a pressure block 76, and a sealing ring 77. The explosion-proof valve and the protective plate 72 are both mounted on the end cap 71. Along the thickness direction of the end cap 71, the lower insulating member 73 is located on one side of the end cap 71. The upper insulating member 74 is mounted on the side of the end cap 71 opposite to the lower insulating member 73. There are two upper insulating members 74, spaced apart along the length direction of the first end cap assembly 70a.

[0073] Along the thickness direction of the first end cap assembly 70a, the electrode post 75 passes through the end cap 71, the lower insulator 73, and the upper insulator 74, and is disposed in the first mounting hole 421 and the second mounting hole 424 of the first connector 40a, and is electrically connected to the electrode post connection portion 42 of the first connector 40a. For example, the electrode post 75 and the electrode post connection portion 42 of the first connector 40a are electrically connected by seam welding to ensure a high current-carrying capacity between the electrode post 75 and the first connector 40a. There are two electrodes 75, one used as a positive electrode post and the other as a negative electrode post. Each electrode post 75 passes through the end cap 71, the lower insulator 73, and the upper insulator 74, and is disposed in the first mounting hole 421 and the second mounting hole 424 of one first connector 40a, and is electrically connected to the electrode post connection portion 42 of one first connector 40a.

[0074] A pressure block 76 is installed on the upper insulating member 74 and sleeved on the pole post 75, and is fixedly connected to the pole post 75. There are two pressure blocks 76, each installed on one upper insulating member 74 and sleeved on one pole post 75, and fixedly connected to the pole post 75. A sealing ring 77 is sleeved on the pole post 75 and clamped between the end cap 71 and the pole post 75. There are two sealing rings 77, each sleeved on one pole post 75 and clamped between the end cap 71 and the pole post 75.

[0075] It should be noted that in this embodiment, the structure of the second end cap assembly 70b is the same as that of the first end cap assembly 70a. The relevant structure of the second end cap assembly 70b can be referred to the relevant description of the first end cap assembly 70a, and will not be repeated here. Specifically, along the thickness direction of the second end cap assembly 70b, the pole post 75 passes through the end cap 71, the lower insulating member 73, and the upper insulating member 74, and is disposed in the mounting hole 401 of the second connector 40b, and is electrically connected to the first connector 40a. In some other embodiments, the structure of the second end cap assembly 70b may differ from that of the first end cap assembly 70a, and this application does not impose specific limitations on this.

[0076] In the energy storage device 5 shown in this embodiment, the flexible connection portion 43 of the first connector 40a allows the first connector 40a to bend, enabling the first tab 22 and the second tab 24 of the battery cell assembly 20 to be simultaneously welded to the first connector 40a and the second connector 40b before being installed in the housing. Compared to the assembly method where one tab is connected to the adapter plate before installation and the other tab is welded to the adapter plate after installation, this not only simplifies the assembly process of the energy storage device 5, improves its assembly efficiency, and enhances its competitiveness, but also shortens the tab length, saving production costs. Furthermore, the multi-layer design of the flexible connection portion 43 can improve the current-carrying capacity of the first connector 40a due to the skin effect of the current, thus contributing to improved electrical performance of the energy storage device 5.

[0077] This application also provides an electrical device, which includes the aforementioned energy storage device 5, and the energy storage device 5 supplies power to the electrical device. The electrical device can be a new energy vehicle, a power storage station, a server, or other equipment that requires electricity.

[0078] Please see Figure 14 , Figure 14 This is a process flow diagram of the assembly method of the energy storage device provided in this application.

[0079] This application also provides a method for assembling an energy storage device, used for assembling the energy storage device 5 described above. The method for assembling the energy storage device includes steps S1 to S9.

[0080] Step S1 involves providing a housing 10, a cell assembly 20, a spacer 30, a first connector 40a, a second connector 40b, a first end cap assembly 70a, and a second end cap assembly 70b. The housing 10 has a receiving cavity 101, a first opening 102a, and a second opening. The cell assembly 20 includes a cell body 21, a first electrode 22, and a second electrode 24. The first connector 40a includes an electrode connecting portion 41, an electrode post connecting portion 42, and a flexible connecting portion 43. Both the first end cap assembly 70a and the second end cap assembly 70b include electrode posts. Furthermore, step S1 also includes providing two Mylar plates 50 and two air guide plates 60.

[0081] Step S2: Electrically connect the second connector 40b to the terminal post of the second end cap assembly 70b. The terminal post of the second end cap assembly 70b passes through the mounting hole 401 of the second connector 40b and is electrically connected to the second connector 40b. For example, the electrical connection between the terminal post of the second end cap assembly 70b and the second connector 40b is achieved through seam welding.

[0082] Step S3: Electrically connect the second connector 40b to the second tab 24.

[0083] Step S4: Electrically connect the tab connection portion 41 of the first connector 40a to the first tab 22. For example, the tab connection portion 41 of the first connector 40a is electrically connected to the first tab 22 by ultrasonic welding or laser welding.

[0084] Step S5 involves passing the first connector 40a through the spacer 30. Specifically, the terminal connection portion 42 of the first connector 40a passes through the spacer 30. The terminal connection portion 42 of the first connector 40a passes through the through hole 311 of the spacer 30. Furthermore, step S3 also includes mounting two Mylar plates 50 on opposite sides of the cell body 21 of the cell assembly 20 along the thickness direction, and mounting two air guide plates 60 on opposite sides of the cell body 21 of the cell assembly 20 along the width direction.

[0085] Step S6 involves assembling the cell assembly 20, spacer 30, first connector 40a, and second connector 40b into the receiving cavity 101. The terminal connection portion 42 of the first connector 40a extends out of the first opening 102a. Furthermore, step S4 also includes assembling two Mylar plates 50 and two air guide plates 60 into the receiving cavity 101 of the housing 10.

[0086] Step S7: Install the second end cap assembly 70b onto the housing 10, wherein the second end cap assembly 70b closes the second opening. Specifically, weld the end cap of the second end cap assembly 70b to the housing 10.

[0087] Step S8: Electrically connect the pole connection portion 42 of the first connector 40 to the pole 75 of the first end cap assembly 70a.

[0088] Please see Figure 15 , Figure 15 yes Figure 14 The structural diagram of step S8 in the process flow diagram shown.

[0089] Specifically, the pole post 75 of the first end cap assembly 70a passes through the first mounting hole 421 and the second mounting hole 424 of the first connector 40a, and is electrically connected to the pole post connecting portion 42 of the first connector 40a. For example, the pole post 75 of the first end cap assembly 70a achieves electrical connection with the pole post connecting portion 42 of the first connector 40a through a seam welding method.

[0090] Step S9: Install the first end cap assembly 70a onto the housing 10, wherein the first end cap assembly 70a closes the first opening 102a. Specifically, fold the first end cap assembly 70a to drive the first connector 40a from a flattened state to a bent state, and weld the end cap 71 of the first end cap assembly 70a to the housing 10.

[0091] In the energy storage device 5 shown in this embodiment, the flexible connection portion 43 of the first connector 40a allows the first connector 40a to bend, enabling the first tab 22 and the second tab 24 of the battery cell assembly 20 to be simultaneously welded to the first connector 40a and the second connector 40b before being installed in the housing. Compared to the assembly method where one tab is connected to the adapter plate before installation and the other tab is welded to the adapter plate after installation, this not only simplifies the assembly process of the energy storage device 5, improves its assembly efficiency, and enhances its competitiveness, but also shortens the tab length, saving production costs. Furthermore, the multi-layer design of the flexible connection portion 43 can improve the current-carrying capacity of the first connector 40a due to the skin effect of the current, thus contributing to improved electrical performance of the energy storage device 5.

[0092] The above description is merely a specific embodiment of this application, but 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. Where there is no conflict, the embodiments and features in the embodiments of this application can be combined with each other. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A connector for use in an energy storage device, characterized in that, The device includes a tab connection portion, a pole connection portion, and a flexible connection portion. The tab connection portion is used to electrically connect the tab, the pole connection portion is used to electrically connect the pole, and the flexible connection portion is connected between the pole connection portion and the tab connection portion. The flexible connection portion includes multiple layers of first foil material, which are stacked along the thickness direction of the flexible connection portion. The flexibility of the flexible connection portion is greater than the flexibility of the pole connection portion and the flexibility of the tab connection portion.

2. The connector according to claim 1, characterized in that, The pole connection portion includes multiple layers of second foil material. The multiple layers of second foil material are stacked along the thickness direction of the pole connection portion, and each adjacent two layers of second foil material are connected to each other. The tab connection includes multiple layers of third foil. The multiple layers of third foil are stacked along the thickness direction of the tab connection, and each pair of adjacent layers of third foil are connected to each other. Each layer of the first foil is connected between a layer of the second foil and a layer of the third foil.

3. The connector according to claim 2, characterized in that, The first foil, the second foil, and the third foil, which are located on the same layer, are integrally formed.

4. The connector according to claim 2 or 3, characterized in that, The thickness of the pole post connector is greater than the thickness of the tab connector and the thickness of the flexible connector.

5. The connector according to claim 2 or 3, characterized in that, The pole connection portion further includes a conductive element, which is located on one side of the second foil and connected to the second foil along the thickness direction of the pole connection portion.

6. The connector according to claim 5, characterized in that, The conductive element is located on the side of the second foil facing the electrode post; The electrode connection portion is provided with a first mounting hole and a second mounting hole. The first mounting hole penetrates multiple layers of the second foil material along the thickness direction of the electrode connection portion. The second mounting hole penetrates the conductive element along the thickness direction of the electrode connection portion. The second mounting hole includes a first hole portion and a second hole portion. The first hole portion communicates with the first mounting hole. The second hole portion is located on the side of the first hole portion away from the first mounting hole and communicates with the first hole portion. Along the direction from the second hole portion to the first hole portion, the diameter of the second hole portion gradually decreases. Both the first mounting hole and the second mounting hole are used to install the electrode.

7. The connector according to claim 2, characterized in that, The multilayer first foil material includes a first inner foil material and a first outer foil material, and the first inner foil material and the first outer foil material are disposed opposite to each other along the thickness direction of the flexible connection portion; The multilayer second foil includes a second inner foil and a second outer foil. Along the thickness direction of the pole post connection, the second inner foil and the second outer foil are arranged opposite to each other, and the second outer foil is located on the side of the second inner foil closer to the pole post. The multilayer third foil material includes a third inner foil material and a third outer foil material. Along the thickness direction of the tab connection portion, the third inner foil material and the third outer foil material are arranged opposite to each other. The first inner foil material is connected between the second inner foil material and the third inner foil material, and the first outer foil material is connected between the second outer foil material and the third outer foil material. When the connector is in a bent state, the second inner foil and the third inner foil are spaced apart and arranged opposite each other, and the second outer foil and the third outer foil are arranged opposite each other. Along the direction from the first inner foil to the first outer foil, the length of the multiple layers of the first foil gradually increases.

8. The connector according to claim 2, characterized in that, The lengths of the first foil materials in multiple layers are the same.

9. The connector according to claim 7 or 8, characterized in that, The second foil layers are of the same length, and / or the third foil layers are of the same length.

10. The connector according to any one of claims 1 to 3, characterized in that, The pole post connection portion has a first surface, a second surface, a first circumferential side surface, and a second circumferential side surface. The second surface is located on the side of the first surface away from the pole post and is disposed opposite to the first surface. The first circumferential side surface is connected between the first surface and the second surface. The second circumferential side surface is located on the side of the first circumferential side surface facing the flexible connection portion and is disposed opposite to the first circumferential side surface, and is connected to the first surface. Along the direction from the first circumferential side surface to the second circumferential side surface, the distance between the second circumferential side surface and the second surface gradually decreases.

11. The connector according to any one of claims 1 to 3, characterized in that, The width of the first foil material is the same in multiple layers.

12. The connector according to any one of claims 1 to 3, characterized in that, The thickness of each layer of the first foil is between 0.03 mm and 0.5 mm.

13. An energy storage device, characterized in that, The device includes a housing, a battery cell assembly, a spacer, a first end cap assembly, a second end cap assembly, a first connector, and a second connector. The housing has a receiving cavity, a first opening, and a second opening. The receiving cavity is located inside the housing. The first opening and the second opening are located on opposite sides of the receiving cavity and are both in communication with the receiving cavity. The battery cell assembly is housed in the receiving cavity and includes a first tab and a second tab. The first end cap assembly and the second end cap assembly are both mounted on the housing. The spacer is mounted in the receiving cavity and is located on one side of the battery cell assembly. The first end cap assembly closes the first opening, and the second end cap assembly closes the second opening. The first connector passes through the spacer. The first connector is the connector according to claim 1 and is in a bent state. The tab connection portion is electrically connected to the first tab. The pole connection portion is spaced apart from and opposite to the tab connection portion and is electrically connected to the pole of the first end cap assembly. The second connector is electrically connected between the second tab and the pole of the second end cap assembly.

14. The energy storage device according to claim 13, characterized in that, The pole connection portion includes multiple layers of second foil material. The multiple layers of second foil material are stacked along the thickness direction of the pole connection portion, and each adjacent two layers of second foil material are connected to each other. The tab connection includes multiple layers of third foil. The multiple layers of third foil are stacked along the thickness direction of the tab connection, and each pair of adjacent layers of third foil are connected to each other. Each layer of the first foil is connected between a layer of the second foil and a layer of the third foil.

15. The energy storage device according to claim 14, characterized in that, The first foil, the second foil, and the third foil, which are located on the same layer, are integrally formed.

16. The energy storage device according to claim 14 or 15, characterized in that, The thickness of the pole post connector is greater than the thickness of the tab connector and the thickness of the flexible connector.

17. The energy storage device according to claim 14 or 15, characterized in that, The pole connection portion further includes a conductive element, which is located on one side of the second foil and connected to the second foil along the thickness direction of the pole connection portion.

18. The energy storage device according to claim 17, characterized in that, The conductive element is located on the side of the second foil facing the electrode post; The electrode connection portion is provided with a first mounting hole and a second mounting hole. The first mounting hole penetrates multiple layers of the second foil material along the thickness direction of the electrode connection portion. The second mounting hole penetrates the conductive element along the thickness direction of the electrode connection portion. The second mounting hole includes a first hole portion and a second hole portion. The first hole portion communicates with the first mounting hole. The second hole portion is located on the side of the first hole portion away from the first mounting hole and communicates with the first hole portion. Along the direction from the second hole portion to the first hole portion, the diameter of the second hole portion gradually decreases. Both the first mounting hole and the second mounting hole are used to install the electrode.

19. The energy storage device according to claim 14, characterized in that, The multilayer first foil material includes a first inner foil material and a first outer foil material, and the first inner foil material and the first outer foil material are disposed opposite to each other along the thickness direction of the flexible connection portion; The multilayer second foil includes a second inner foil and a second outer foil. Along the thickness direction of the pole post connection, the second inner foil and the second outer foil are arranged opposite to each other, and the second outer foil is located on the side of the second inner foil closer to the pole post. The multilayer third foil material includes a third inner foil material and a third outer foil material. Along the thickness direction of the tab connection portion, the third inner foil material and the third outer foil material are arranged opposite to each other. The first inner foil material is connected between the second inner foil material and the third inner foil material, and the first outer foil material is connected between the second outer foil material and the third outer foil material. The second inner foil and the third inner foil are spaced apart and arranged opposite to each other, while the second outer foil and the third outer foil are arranged opposite to each other. The length of the multiple layers of the first foil gradually increases along the direction from the first inner foil to the first outer foil.

20. The energy storage device according to claim 14, characterized in that, The lengths of the first foil materials in multiple layers are the same.

21. The energy storage device according to claim 19 or 20, characterized in that, The second foil layers are of the same length, and / or the third foil layers are of the same length.

22. The energy storage device according to any one of claims 13 to 15, characterized in that, The pole post connection portion has a first surface, a second surface, a first circumferential side surface, and a second circumferential side surface. The second surface is located on the side of the first surface away from the pole post and is disposed opposite to the first surface. The first circumferential side surface is connected between the first surface and the second surface. The second circumferential side surface is located on the side of the first circumferential side surface facing the flexible connection portion and is disposed opposite to the first circumferential side surface, and is connected to the first surface. Along the direction from the first circumferential side surface to the second circumferential side surface, the distance between the second circumferential side surface and the second surface gradually decreases.

23. The energy storage device according to any one of claims 13 to 15, characterized in that, The width of the first foil material is the same in multiple layers.

24. The energy storage device according to any one of claims 13 to 15, characterized in that, The thickness of each layer of the first foil is between 0.03 mm and 0.5 mm.

25. An electrical appliance, characterized in that, Includes the energy storage device as described in any one of claims 13 to 24, wherein the energy storage device supplies power to electrical equipment.

26. A method for assembling an energy storage device, characterized in that, include: A housing, a battery cell assembly, a spacer, a first connector, a second connector, a first end cap assembly, and a second end cap assembly are provided. The housing includes a receiving cavity, a first opening, and a second opening. The receiving cavity is located inside the housing. The first opening and the second opening are located on opposite sides of the receiving cavity and are both in communication with the receiving cavity. The battery cell assembly includes a first electrode and a second electrode. The first connector is the connector described in any one of claims 1 to 12. Both the first end cap assembly and the second end cap assembly include a terminal post. The second connector is electrically connected to the pole of the second end cap assembly; Electrically connect the second connector to the second electrode ear; The electrode connecting portion of the first connector is electrically connected to the first electrode; Pass the first connector through the spacer ring; The cell assembly, the spacer, the first connector, and the second connector are assembled into the receiving cavity; The second end cap assembly is installed on the housing, wherein the second end cap assembly closes the second opening; The pole connection portion of the first connector is electrically connected to the pole of the first end cap assembly; The first end cap assembly is installed on the housing, wherein the first end cap assembly closes the first opening.

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