Energy storage devices and electrical equipment

Abstract

The present application discloses an energy storage device and an electrical equipment, wherein the energy storage device comprises a shell and a battery cell and an end cap assembly mounted in the shell. The battery cell comprises a battery cell body, a first pole lug group and a second pole lug group, and the first pole lug group and the second pole lug group are both led out from the side of the battery cell body. The end cap assembly comprises a first pin and a second pin, and the first pin comprises a first adapter, which has an overlapping portion with the first pole lug group. The second pin comprises a second adapter. It has an overlapping portion with the second pole lug group. The first pole lug group comprises a first outer side surface, and the ratio of the width of the overlapping portion of the first pole lug group and the first adapter to the straight-line distance from the first outer side surface to the central axis in the length direction of the battery cell is greater than or equal to 5 / 7 and less than or equal to 6 / 7. The second pole lug group comprises a second outer side surface, and the ratio of the width of the overlapping portion of the second pole lug group and the second adapter to the straight-line distance from the second outer side surface to the central axis in the length direction of the battery cell is greater than or equal to 4 / 7 and less than or equal to 5 / 7.

Description

Technical Field

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

[0002] With the continuous advancement of energy storage technology, consumers have higher and higher requirements for the energy density inside energy storage devices. In order to improve the space utilization inside the energy storage device, existing large-capacity energy storage devices mostly use laminated cells and use pins as conductive components to achieve electrical conduction between the cells and the poles. However, there is a difference in the conductivity of the existing positive pins and the conductivity of the negative pins. When the size of the positive pin and the negative pin is set to the same and the size of the positive and negative pole ears is also set to the same, the energy storage device will have a difference in the current flow capacity of the negative pin and the positive pin, thereby reducing the consistency of the energy storage device. Summary of the invention

[0003] The present application provides an energy storage device and electrical equipment, which can compensate for the difference in current overcurrent capacity between the positive pin and the negative pin and improve the consistency of the energy storage device.

[0004] The embodiment of the present application provides an energy storage device, the energy storage device includes a shell, a battery cell and an end cap assembly, the shell includes an opening. The battery cell is installed in the shell, the battery cell includes a battery cell body, a first pole tab group and a second pole tab group, the battery cell body includes a first side surface and a second side surface, the first side surface and the second side surface are arranged opposite to each other along the length direction of the battery cell body, the first pole tab group is led out from the first side surface, and the second pole tab group is led out from the second side surface. The end cap assembly is installed at one end of the battery cell and sealed in the opening, the end cap assembly includes a first pin and a second pin, the first pin includes a first transition portion, the first transition portion is overlapped on the first side surface, the first pole tab group covers and connects the first transition portion, and the first pole tab group and the first transition portion have an overlapped portion, the second pin includes a second transition portion, the second transition portion is overlapped on the second side surface, the second pole tab group covers and connects the second transition portion, and the second pole tab group and the second transition portion have an overlapped portion, and the size of the first transition portion is not equal to the size of the second transition portion.

[0005] The first pole lug group includes a first outer side surface, the first outer side surface is opposite to the first transition portion, the straight-line distance between the first outer side surface and the central axis of the battery cell in the length direction is D1, and the width of the overlapping portion of the first pole lug group and the first transition portion in the width direction of the battery cell is D2, wherein the ratio of D2 to D1 is greater than or equal to 5 / 7 and less than or equal to 6 / 7.

[0006] The second pole lug group includes a second outer side surface, the second outer side surface is opposite to the second transition portion, the straight-line distance between the second outer side surface and the central axis in the length direction of the battery cell is D3, and the width of the overlapping portion of the second pole lug group and the second transition portion in the width direction of the battery cell is D4, wherein the ratio of D4 to D3 is greater than or equal to 4 / 7 and less than or equal to 5 / 7.

[0007] It can be understood that in the related art, due to the different materials of the positive pin and the negative pin, the conductivity of the positive pin and the conductivity of the negative pin are different. When the size of the positive pin and the negative pin is set to be the same and the size of the positive pole ear and the negative pole ear is also set to be the same, that is, the contact area of ​​the positive pole ear to the positive pin is equal to the contact area of ​​the negative pole ear to the negative pin, therefore, there is a difference in the current overcurrent capacity of the negative pin and the positive pin. For example, in the case where both the positive pin and the negative pin meet the current overcurrent, the negative pin will have a problem of excess material, thereby reducing the material utilization rate of the negative pin, which is not conducive to the consistency of the energy storage device. Alternatively, in the case where the negative pin just meets the current overcurrent, the positive pin with the same size as the negative pin will be subjected to higher heat when the current is overcurrent. As the battery cell is repeatedly charged and discharged, the service life of the positive pin is generally lower than that of the negative pin, reducing the consistency of the energy storage device.

[0008] In the embodiment of the present application, the first pin and the second pin have different sizes, and the first pole lug group and the second pole lug group also have different sizes. Therefore, under the requirement of current overcurrent between the first pole lug group and the first pin, the width of the contact portion between the first pole lug group and the first pin is different. At the same time, under the requirement of current overcurrent between the second pole lug group and the second pin, the width of the contact portion between the second pole lug group and the second pin is also different, which solves the problem of difference in current overcurrent capacity between the first pin and the second pin. Specifically, the ratio setting of D2 to D1 not only avoids the overlap of the first attachment sections of the two first pole lug groups in the length direction of the battery cell, but also ensures that the contact area between the first pole lug group and the first adapter can meet the current overcurrent, so as to avoid the contact area between the first pole lug group and the first adapter being too small, resulting in excessive local heating of the first adapter, and reducing the influence of heat on the first pin. The ratio setting of D4 to D3 not only avoids the overlap of the second attachment sections of the two second tab groups in the length direction of the battery cell, but also ensures that the contact area between the second tab group and the second adapter can meet the current overcurrent, so as to avoid the contact area between the second tab group and the second adapter being too small, resulting in excessive local heating of the second adapter, and reducing the influence of heat on the second pin. In addition, the influence of heat on the first pin and the second pin is reduced, which is conducive to ensuring the temperature consistency and service life consistency of the first pin and the second pin, and further conducive to the consistency of the energy storage device.

[0009] In one embodiment, the first pole tab group includes a plurality of first pole tabs, which are stacked along the thickness direction of the first pole tab group, and the plurality of first pole tabs are pre-welded by ultrasonic welding and cut to form the first pole tab group, and the second pole tab group includes a plurality of second pole tabs, which are stacked along the thickness direction of the second pole tab group, and the plurality of second pole tabs are pre-welded by ultrasonic welding and cut to form the second pole tab group.

[0010] When the first electrode tab group and the second electrode tab group are under the same welding power, the number of the first electrode tabs and the number of the second electrode tabs are not equal.

[0011] It can be understood that when the first and second pole lug groups are under the same welding power, the number of positive pole lugs in the first pole lug group and the number of negative pole lugs in the second pole lug group may not be equal. That is, the number of positive pole lugs in the first pole lug group and the number of negative pole lugs in the second pole lug group can be reasonably matched according to the actual welding power to accommodate the situation where the number of first pole lugs in the first pole lug group and the number of second pole lugs in the second pole lug group are different, ensuring that the multiple first pole lugs constituting the first pole lug group can be welded through, improving the connection reliability between the first pole lug group and the first pin, and at the same time, ensuring that the multiple second pole lugs constituting the second pole lug group can be welded through, improving the connection reliability between the second pole lug group and the second pin.

[0012] In one embodiment, the first electrode tab includes a first end electrode tab, a surface of the first end electrode tab before pre-welding is a first outer surface, a portion of the surface of the first end electrode tab after pre-welding is the first outer side surface of the first electrode tab group, and a straight-line distance from the first outer surface to the first outer side surface is less than a length of the first end electrode tab;

[0013] The second pole lug includes a second end pole lug, the surface of the second end pole lug before pre-welding is the second outer surface, and a portion of the surface of the second end pole lug after pre-welding is the second outer side surface of the second pole lug group, and a straight-line distance from the position of the second outer surface to the position of the second outer side surface is less than the length of the second end pole lug.

[0014] It can be understood that the situation that the current overcurrent of the first pole lug group formed by the inconsistent length of the plurality of first pole lugs is inconsistent with that of the first pin is avoided, and the plurality of first pole lugs constituting a first pole lug group can be welded and combined and electrically connected to the first pin. At the same time, the situation that the current overcurrent of the second pole lug group formed by the inconsistent length of the plurality of second pole lugs is inconsistent with that of the second pin is avoided, and the plurality of second pole lugs constituting a second pole lug group can be welded and combined and electrically connected to the second pin is ensured.

[0015] It can be understood that the condition that the straight-line distance from the position of the first outer surface to the position of the first outer side surface is less than the length of the first end pole ear is satisfied, and at the same time, the condition that the straight-line distance from the position of the second outer surface to the position of the second outer side surface is less than the length of the second end pole ear is satisfied, so that the current overcurrent of the first pole ear group and the first pin and the current overcurrent of the second pole ear group and the second pin are consistent, which is conducive to the service life of the first pin and the second pin being consistent, and further conducive to the consistency of the energy storage device.

[0016] In one embodiment, the number of the first pole lug groups is two, the two first pole lug groups are respectively located on opposite sides of the width direction of the first transition portion and are bent toward the first transition portion, each of the first pole lug groups includes a first attachment section, the two first attachment sections extend relatively along the width direction of the first transition portion and are both attached to the surface of the first transition portion facing away from the first side surface, and the first attachment section is connected to the first transition portion by laser welding.

[0017] There are two second pole lug groups, the two second pole lug groups are respectively located on opposite sides of the width direction of the second transition portion and are bent toward the second transition portion, each second pole lug group includes a second attachment section, the two second attachment sections extend toward each other along the width direction of the second transition portion and are both attached to the surface of the second transition portion facing away from the second side surface, and the second attachment section is connected to the second transition portion by laser welding.

[0018] It can be understood that the two first attachment sections are connected to the first adapter by laser welding and electrically conductive, so as to increase the current flow path between the first pole lug group and the first adapter, which is conducive to dispersing the heat generated when the current flows between the first pole lug group and the first adapter. At the same time, the two second attachment sections are connected to the second adapter by laser welding and electrically conductive, so as to increase the current flow path between the second pole lug group and the second adapter, which is conducive to dispersing the heat generated when the current flows between the second pole lug group and the second adapter. The influence of heat on the first pin and the second pin is reduced, which is conducive to ensuring the temperature consistency and service life consistency of the first pin and the second pin.

[0019] In addition, the design of the first tab group avoids the first tab group being too long and increasing the manufacturing cost of the first tab group. At the same time, the design of the second tab group avoids the second tab group being too long and increasing the manufacturing cost of the second tab group.

[0020] In one embodiment, each of the first electrode tab groups further includes a first lead-out section and a first middle section, the first lead-out section is connected to the first side surface and is electrically conductive with the battery cell body, the first middle section is connected to the first lead-out section and is connected at an angle to the first attachment section, the first middle section has the first outer side surface, and the first transition portion includes a first transition inner surface, the first transition inner surface faces the first lead-out section and is spaced from the first side surface.

[0021] Each of the first electrode tab groups also includes a second lead-out section and a second middle section, the second lead-out section is connected to the second side surface and is electrically conductive with the battery cell body, the second middle section is connected to the second lead-out section and is connected at an angle to the second attachment section, the second middle section has the second outer side surface, and the second transition portion includes a second transition inner surface, the second transition inner surface faces the second lead-out section and is spaced from the second side surface.

[0022] It can be understood that the first lead section of the first pole tab group is electrically connected to the battery body, and the first attachment section of the first pole tab group is electrically connected to the first transition section to achieve electrical conduction between the battery body and the first pin. The first transition section is spaced from the first side surface to avoid a short circuit between the battery body and the first transition section. The second lead section of the second pole tab group is electrically connected to the battery body, and the second attachment section of the second pole tab group is electrically connected to the second transition section to achieve electrical conduction between the battery body and the second pin. The second transition section is spaced from the second side surface to avoid a short circuit between the battery body and the second transition section.

[0023] In one embodiment, the thickness of the first attachment section is greater than or equal to 1 mm and less than or equal to 2 mm. The thickness of the second attachment section is greater than or equal to 1 mm and less than or equal to 2 mm.

[0024] It can be understood that the thickness of the first attachment section not only ensures that the plurality of first pole tabs can be welded through to form a stable first pole tab group when ultrasonic welding is performed, but also ensures good welding between the first attachment section and the first transition portion. The thickness of the second attachment section not only ensures that the plurality of second pole tabs can be welded through to form a stable second pole tab group when ultrasonic welding is performed, but also ensures good welding between the second attachment section and the second transition portion.

[0025] In one embodiment, the first tab group includes a first ultrasonic welding area and a first laser welding area, the first ultrasonic welding area and the first laser welding area are both located in the first attachment section, the first laser welding area is completely located in the first ultrasonic welding area, the ratio of the area of ​​the first laser welding area to the area of ​​the first ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the first laser welding area completely covers the first transition portion.

[0026] The second tab group includes a second ultrasonic welding area and a second laser welding area, the second ultrasonic welding area and the second laser welding area are both located in the second attachment section, the second laser welding area is completely located in the second ultrasonic welding area, the ratio of the area of ​​the second laser welding area to the area of ​​the second ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the second laser welding area completely covers the second transition portion.

[0027] It can be understood that the area of ​​the first laser welding zone is smaller than the area of ​​the first ultrasonic welding zone, which prevents the laser energy generated during the laser welding of the first attachment section and the first transition section from being incident on the first outer side surface, thereby preventing the laser energy from being reflected by the smooth surface, reducing the waste of laser energy, and ensuring the welding effect of the first tab group and the first pin during the laser welding. At the same time, the area of ​​the second laser welding zone is smaller than the area of ​​the second ultrasonic welding zone, which prevents the laser energy generated during the laser welding of the second attachment section and the second transition section from being incident on the second outer side surface, thereby preventing the laser energy from being reflected by the smooth surface, reducing the waste of laser energy, and ensuring the welding effect of the second tab group and the second pin during the laser welding.

[0028] In one embodiment, the first laser welding area includes a first short side and a first narrow side, the first ultrasonic welding area includes a first long side and a first wide side, the first long side is parallel to the first short side, and the spacing between the first long side and the adjacent first short side is greater than or equal to 2 mm and less than or equal to 5 mm, the first wide side is parallel to the first narrow side, and the spacing between the first wide side and the adjacent first narrow side is greater than or equal to 1 mm and less than or equal to 2 mm.

[0029] The second laser welding area includes a second short side and a second narrow side, the second ultrasonic welding area includes a second long side and a second wide side, the second long side is parallel to the second short side, and the spacing between the second long side and the adjacent second short side is greater than or equal to 2 mm and less than or equal to 5 mm, the second wide side is parallel to the second narrow side, and the spacing between the second wide side and the adjacent second narrow side is greater than or equal to 1 mm and less than or equal to 2 mm.

[0030] It can be understood that the orthographic projection of the first laser welding zone on the first tab group is completely located in the first ultrasonic welding zone, and the orthographic projection of the second laser welding zone on the second tab group is completely located in the second ultrasonic welding zone.

[0031] In one embodiment, the length of the first tab group is greater than or equal to 25.5 mm and less than or equal to 29.5 mm. The length of the second tab group is greater than or equal to 22 mm and less than or equal to 26 mm.

[0032] It can be understood that when the first tab group is attached to the first adapter, the contact area of ​​the first tab group to the first adapter is satisfied, thereby satisfying the current overflow between the first tab group and the first pin. When the second tab group is attached to the second adapter, the contact area of ​​the second tab group to the second adapter is satisfied, thereby satisfying the current overflow between the second tab group and the second pin.

[0033] An embodiment of the present application further provides an electric device, wherein the electric device includes the energy storage device, and the energy storage device supplies power to the electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is an application scenario diagram of the energy storage device provided in the embodiment of the present application;

[0035] Figure 2 A schematic diagram of the structure of the energy storage device provided in the embodiment of the present application;

[0036] Figure 3 for Figure 1 A schematic diagram of the exploded structure of the energy storage device shown;

[0037] Figure 4 for Figure 3 A schematic diagram of the structure of the first pin and the second pin of the end cover assembly in the energy storage device shown;

[0038] Figure 5 for Figure 3 A schematic diagram of a partial structure of a battery cell in the energy storage device shown;

[0039] Figure 6 for Figure 3 A schematic diagram of the partial structure of a battery cell in the energy storage device shown at another angle;

[0040] Figure 7 for Figure 3 A schematic cross-sectional view of a portion of the structure of the energy storage device shown;

[0041] Figure 8 for Figure 2 A side view of a portion of the structure of the energy storage device shown;

[0042] Fig. 9 for Figure 8 A schematic cross-sectional view of a portion of the structure of the energy storage device shown;

[0043] Fig.10 for Figure 2 A side view of a portion of the structure of the energy storage device shown at another angle;

[0044] Fig.11 for Fig.10 A schematic diagram of the cross-sectional structure of part of the energy storage device shown at another angle.

[0045] The nouns corresponding to the reference numerals in the figure are: energy storage device 1000, housing 200, opening 201, accommodating cavity 202, end cover assembly 100, end cover 10, top surface 11, bottom surface 12, first through hole 13, second through hole 14, lower plastic 20, upper surface 21, lower surface 22, first pole through hole 23, second pole through hole 24, first pole 30, second pole 40, first pin 50, first connecting portion 51, first through hole 511, first adapter portion 52, first adapter inner surface 521, first transfer outer surface 522, first surface 523, second pin 60, second connection portion 61, second through hole 611, second transfer portion 62, second transfer inner surface 621, second transfer outer surface 622, second surface 623, battery cell 300, battery cell body 310, first side surface 311, second side surface 312, first tab group 320, first end tab a, first outer surface 321, first inner surface 322, first end surface 323, first lead section 324, first attachment Segment 325, first inner surface 3251, first outer surface 3252, first middle segment 326, first inner side surface 3261, first outer side surface 3262, first ultrasonic welding area 327, first long side 3271, first wide side 3272, first laser welding area 328, first short side 3281, first narrow side 3282, second tab group 330, second end tab b, second outer surface 331, second inner surface 332, second end surface 333, second lead segment 334, second attachment segment 335, second inner surface 3351, second outer surface 3352, second middle section 336, second inner side surface 3361, second outer side surface 3362, second ultrasonic welding area 337, second long side 3371, second wide side 3372, second laser welding area 338, second short side 3381, second narrow side 3382, first electrical equipment 3000, second electrical equipment 2000, first electric energy conversion device 4100, second electric energy conversion device 4200, energy storage system 5000. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] In this application, unless otherwise specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, they can be fixedly connected, detachably connected, or integrated; they can be mechanically connected, electrically connected, or able to communicate with each other; they can be directly connected, or indirectly connected through an intermediate medium, and they can be internally connected between two elements or the interaction relationship between two elements, unless otherwise specified and limited. And the terms "same", "equal" or "parallel" used in the following text are allowed to have a certain tolerance.

[0048] It should be noted that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include at least one of the features.

[0049] Since the energy people need is highly temporal and spatial, in order to rationally utilize energy and improve energy utilization, it is necessary to use a medium or device to store one form of energy in the same form or convert it into another form of energy, and then release it in a specific form of energy based on future application needs. At present, the generation of green electricity generally relies on photovoltaics, wind power, water potential, etc., while wind and solar energy generally have problems of strong intermittency and large volatility, which will cause instability of the power grid, insufficient electricity during peak hours, too much electricity during low hours, and unstable voltage will also cause damage to electricity. Therefore, it may cause "wind and light abandonment" problems due to insufficient electricity demand or insufficient grid acceptance capacity. To solve these problems, energy storage must be relied on. That is, electrical energy is converted into other forms of energy by physical or chemical means and stored, and energy is converted into electrical energy and released when needed. In simple terms, energy storage is similar to a large "power bank". When photovoltaic and wind energy are sufficient, electrical energy is stored and the stored electricity is released when needed.

[0050] Taking electrochemical energy storage as an example, the present application provides an energy storage device 1000, which has a group of chemical batteries inside. The energy storage device 1000 mainly uses the chemical elements in the chemical batteries as energy storage media. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage media. Simply put, the electricity generated by wind energy and solar energy is stored in chemical batteries. When the use of external electricity reaches a peak, the stored electricity is released for use, or transferred to places where electricity is scarce for use.

[0051] At present, energy storage (i.e., energy storage) has a wide range of application scenarios, including (wind and solar) power generation side energy storage, grid side energy storage, base station side energy storage, and user side energy storage. The corresponding types of energy storage devices 1000 include:

[0052] (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, achieve load matching of electric energy in time and space, enhance the ability to absorb renewable energy, and are of great significance in grid system backup, relieving peak load power supply pressure, and peak and frequency regulation;

[0053] (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 in the "peak shaving and valley filling" mode. Since there is a large price difference in electricity prices at peak and valley locations according to electricity demand, after users have energy storage equipment, in order to reduce costs, they usually charge the energy storage cabinets / boxes during the low electricity price period; during the peak electricity price period, the electricity in the energy storage equipment is discharged for use to achieve the purpose of saving electricity bills.

[0054] It should be noted that the above-mentioned energy storage containers, small and medium-sized energy storage cabinets, household small energy storage boxes and other equipment containing the energy storage device 1000 can be understood as electrical equipment.

[0055] See also Figure 1 , Figure 1 It is an application scenario diagram of the energy storage device provided in the embodiment of the present application.

[0056] The energy storage device 1000 provided in the embodiment of the present application is applied to an energy storage system 5000, which includes a first power conversion device 4100 (photovoltaic panel), a second power conversion device 4200 (wind turbine), a first power user 3000 (grid), a second power user 2000 (base station) and an energy storage device 1000. The energy storage system 5000 also includes an energy storage cabinet, and the energy storage device 1000 is installed in the energy storage cabinet, which can be installed outdoors. Specifically, the first power conversion device 4100 can convert solar energy into electrical energy during the period of low electricity prices, and the energy storage device 1000 is used to store the electrical energy and supply the first power user 3000 or the second power user 2000 during peak electricity consumption, or to supply power when the first power user 3000 or the second power user 2000 is powered off / out of power. The second power conversion device 4200 can convert wind energy into electric energy, and the energy storage device 1000 is used to store the electric energy and supply it to the first power device 3000 or the second power device 2000 during peak power consumption, or to supply power when the first power device 3000 or the second power device 2000 is powered off / out of power. The transmission of electric energy can be carried out using a high-voltage cable.

[0057] It should be noted that the first power-consuming device 3000, the second power-consuming device 2000 and other devices including the energy storage device 1000 can be understood as power-consuming devices. The energy storage device 1000 supplies power to the power-consuming devices.

[0058] There may be multiple energy storage devices 1000, and multiple energy storage devices 1000 are connected in series or in parallel. In this embodiment, "multiple" means two or more.

[0059] It can be understood that the energy storage device 1000 may include but is not limited to single cells, battery modules, battery packs, battery systems, etc. The actual application form of the energy storage device 1000 provided in the embodiment of the present application 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 secondary battery such as a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid (or lead-acid) battery, a lithium-ion battery, a polymer lithium-ion battery, etc. When the energy storage device 1000 is a single cell, it may be a cylindrical battery, a square battery, or a battery of other shapes. In this embodiment, the energy storage device 1000 is a square battery. Among them, the square battery is a secondary battery.

[0060] Please also read Figure 2 and Figure 3 , Figure 2 A schematic diagram of the structure of the energy storage device provided in the embodiment of the present application, Figure 3 for Figure 1 Schematic diagram of the exploded structure of the energy storage device shown.

[0061] For ease of description, the width direction of the energy storage device 1000 is defined as the X-axis direction, the length direction is defined as the Y-axis direction, and the height direction is defined as the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are mutually perpendicular.

[0062] The directional terms such as "upper", "top", "lower", "bottom", "left", and "right" mentioned in the description of the embodiments of the present application are based on the Figure 2 The description of the orientation shown does not constitute a limitation on the actual application scenario of the energy storage device 1000. Specifically, the positive direction toward the Z axis is the top of the energy storage device 1000, and the negative direction toward the Z axis is the bottom of the energy storage device 1000.

[0063] The energy storage device 1000 includes an end cap assembly 100, a housing 200 and a battery cell 300. The housing 200 has an opening 201 and is provided with a receiving cavity 202. The opening 201 is connected to the receiving cavity 202. The battery cell 300 is received in the receiving cavity 202. The end cap assembly 100 is mounted on one end of the battery cell 300 and is sealed at the opening 201 to isolate the internal environment of the energy storage device 1000 from the external environment.

[0064] The end cap assembly 100 includes an end cap 10, a lower plastic 20, a first pole 30, a second pole 40, a first pin 50 and a second pin 60. The lower plastic 20 and the end cap 10 are stacked along the Z-axis direction. The length of the lower plastic 20 is the same or substantially the same as the length of the end cap 10. The width of the lower plastic 20 is the same or substantially the same as the width of the end cap 10. The first pole 30 and the second pole 40 are respectively located at opposite ends of the length direction of the end cap assembly 100. The first pole 30 is penetrated through the end cap 10 and the lower plastic 20 and connected to the first pin 50. The second pole 40 is penetrated through the end cap 10 and the lower plastic 20 and connected to the second pin 60. The first pin 50 and the second pin 60 are respectively located at opposite ends of the length direction (i.e., the Y-axis direction) of the battery cell 300. The first pin 50 is partially mounted to the lower plastic 20 and is located on the side of the lower plastic 20 facing away from the end cap 10. The other part of the first pin 50 is connected to the battery cell 300. The battery cell 300 is electrically connected to the first pole 30 through the first pin 50. The second pin 60 is partially mounted to the lower plastic 20 and is located on the side of the lower plastic 20 facing away from the end cover 10. Another part of the second pin 60 is connected to the battery cell 300. The battery cell 300 is electrically connected to the second pole 40 through the second pin 60. In this embodiment, the first pole 30 is a positive pole. The second pole 40 is a negative pole. In some embodiments, the first pole 30 is a negative pole and the second pole 40 is a positive pole.

[0065] In this embodiment, the end cover 10 is a bare aluminum part. The end cover 10 is a long thin plate. The end cover 10 includes a top surface 11 and a bottom surface 12. The top surface 11 and the bottom surface 12 are arranged opposite to each other along the thickness direction of the end cover 10 (i.e., the Z-axis direction). The end cover 10 also includes a first through hole 13 and a second through hole 14. The first through hole 13 and the second through hole 14 both penetrate the top surface 11 and the bottom surface 12. The first through hole 13 and the second through hole 14 are arranged at intervals along the length direction of the end cover 10 (i.e., the Y-axis direction). The first through hole 13 is used for the first pole 30 to pass through. The second through hole 14 is used for the second pole 40 to pass through. The shape of the first through hole 13 and the second through hole 14 can be, but not limited to, a circular, polygonal, rectangular, etc. Exemplarily, the shapes of the first through hole 13 and the second through hole 14 are both circular.

[0066] In this embodiment, the lower plastic 20 is made of an insulating material. The lower plastic 20 is a long thin plate. The lower plastic 20 includes an upper surface 21 and a lower surface 22. The upper surface 21 and the lower surface 22 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the lower plastic 20. The lower plastic 20 also includes a first pole through hole 23 and a second pole through hole 24. The first pole through hole 23 and the second pole through hole 24 both penetrate the upper surface 21 and the lower surface 22. The first pole through hole 23 and the second pole through hole 24 are arranged at intervals along the length direction (i.e., the Y-axis direction) of the lower plastic 20. The first pole through hole 23 is used for the first pole 30 to pass through. The second pole through hole 24 is used for the second pole 40 to pass through. The shape of the first pole through hole 23 and the second pole through hole 24 can be, but not limited to, circular, polygonal, rectangular, etc. Exemplarily, the shapes of the first pole through hole 23 and the second pole through hole 24 are both circular.

[0067] The lower plastic 20 may include a first lower plastic 20 and a second lower plastic 20. The first lower plastic 20 and the second lower plastic 20 may be integrally formed. Alternatively, the first lower plastic 20 and the second lower plastic 20 may be separately formed.

[0068] See also Figure 4 , Figure 4 for Figure 3 A schematic structural diagram of a first pin and a second pin of an end cover assembly in an energy storage device is shown.

[0069] In this embodiment, the first pin 50 is made of aluminum. The first pin 50 is a sheet. The first pin 50 includes a first connecting portion 51 and a first adapter portion 52. The first connecting portion 51 and the first adapter portion 52 are connected at an angle to form an L-shaped structure. The first connecting portion 51 is used to connect to the lower plastic 20 and to be electrically conductive with the first pole 30. The first adapter portion 52 is used to connect to the battery cell 300 and to be electrically conductive with the battery cell 300. It can be understood that the first pin 50 is used to transfer the current of the battery cell 300 to the first pole 30 in sequence through the first adapter portion 52 and the first connecting portion 51.

[0070] Specifically, the first connection portion 51 has a first through hole 511. The first through hole 511 penetrates the two surfaces of the first connection portion 51 in the thickness direction (i.e., the Z-axis direction). The first through hole 511 is used for the first pole 30 to pass through. The shape of the first through hole 511 can be, but is not limited to, circular, polygonal, rectangular, etc. Exemplarily, the shape of the first through hole 511 is circular.

[0071] In this embodiment, the first adapter portion 52 is a rectangular thin plate. The first adapter portion 52 includes a first adapter inner surface 521 and a first adapter outer surface 522. The first adapter inner surface 521 and the first adapter outer surface 522 are arranged opposite to each other along the thickness direction (i.e., the Y-axis direction) of the first adapter portion 52. The first adapter outer surface 522 faces away from the first connecting portion 51. The first adapter portion 52 also includes two first surfaces 523. The two first surfaces 523 are arranged opposite to each other along the width direction of the first adapter portion 52. The two first surfaces 523 are both connected to the first adapter inner surface 521 and the first adapter outer surface 522.

[0072] In this embodiment, the second pin 60 is made of copper. The second pin 60 has a similar structure to the first pin 50. The second pin 60 is a sheet. The second pin 60 includes a second connecting portion 61 and a second adapter portion 62. The second connecting portion 61 and the second adapter portion 62 are connected at an angle to form an L-shaped structure. The second connecting portion 61 is used to connect to the lower plastic 20 and to be electrically conductive with the second pole 40. The second adapter portion 62 is used to connect to the battery cell 300 and to be electrically conductive with the battery cell 300. It can be understood that the second pin 60 is used to transfer the current of the battery cell 300 to the second pole 40 via the second adapter portion 62 and the second connecting portion 61 in sequence.

[0073] Specifically, the second connection portion 61 has a second through hole 611. The second through hole 611 penetrates the two surfaces of the second connection portion 61 in the thickness direction (i.e., the Z-axis direction). The second through hole 611 is used for the second pole 40 to pass through. The shape of the second through hole 611 can be, but is not limited to, circular, polygonal, rectangular, etc. Exemplarily, the shape of the second through hole 611 is circular.

[0074] In this embodiment, the second adapter portion 62 is a rectangular thin plate. The second adapter portion 62 includes a second adapter inner surface 621 and a second adapter outer surface 622. The second adapter inner surface 621 and the second adapter outer surface 622 are arranged opposite to each other along the thickness direction (i.e., the Y-axis direction) of the second adapter portion 62. The second adapter outer surface 622 faces away from the second connecting portion 61. The second adapter portion 62 also includes two second surfaces 623. The two second surfaces 623 are arranged opposite to each other along the width direction of the second adapter portion 62. The two second surfaces 623 are both connected to the second adapter inner surface 621 and the second adapter outer surface 622.

[0075] Please also read Figure 3 , Figure 5 and Figure 6 , Figure 5 for Figure 3 The schematic diagram of the partial structure of the battery cell in the energy storage device shown in FIG. Figure 6 for Figure 3 The schematic diagram of the partial structure of the battery cell in the energy storage device shown in FIG. Figure 5The middle dotted line indicates the boundary between the first attachment section, the first lead section and the first middle section of the first tab group. Figure 6 The middle dotted line indicates the boundary between the second attachment section, the second lead section and the second middle section of the second tab group, and Figure 5 and Figure 6 It shows the state of the battery cell when the tab is not bent.

[0076] In this embodiment, the battery cell 300 is a laminated structure. The battery cell 300 includes a battery cell body 310 and a tab group. The battery cell body 310 is formed by stacking a positive electrode sheet, a negative electrode sheet, and an insulating film located between the positive electrode sheet and the negative electrode sheet. Both the positive electrode sheet and the negative electrode sheet include a first portion coated with an active material and a second portion extending outward from the first portion and not coated with the active material. The battery cell body 310 includes a first side surface 311 and a second side surface 312. The first side surface 311 and the second side surface 312 are arranged opposite to each other along the length direction of the battery cell body 310 (i.e., the Y-axis direction). In this embodiment, the number of battery cell bodies 310 is two. The two battery cell bodies 310 are connected in parallel along the X-axis direction.

[0077] The tab group includes a first tab group 320 and a second tab group 330. The first tab group 320 and the second tab group 330 are both electrically connected to the cell body 310. The first tab group 320 is led out from the first side 311 of the cell body 310 and extends in a direction away from the cell body 310. The first tab group 320 is used to connect to the first pin 50 and be electrically connected. The second tab group 330 is led out from the second side 312 of the cell body 310 and extends in a direction away from the cell body 310. The second tab group 330 is used to connect to the second pin 60 and be electrically connected. In this embodiment, the number of the first tab group 320 and the second tab group 330 is two. Each first tab group 320 is led out from the first side 311 of a cell body 310. Each second tab group 330 is led out from the second side 312 of a cell body 310. The first tab group 320 can be a positive tab group. The second tab group 330 may be a negative tab group. In some other embodiments, the first tab group 320 may be a negative tab group, and the second tab group 330 may be a positive tab group.

[0078] Among them, Figure 5 As shown, the first tab group 320 includes a first outer surface 321, a first inner surface 322 and a first end surface 323. The first outer surface 321 and the first inner surface 322 are arranged opposite to each other along the thickness direction (i.e., the X-axis direction) of the first tab group 320. The first end surface 323 is connected to the first outer surface 321 and the first inner surface 322. The first end surface 323 is away from the first side surface 311 of the battery cell body 310.

[0079] The first pole lug group 320 includes a plurality of first pole lugs (not shown). In the present embodiment, the first pole lug is a positive pole lug, and each first pole lug corresponds to a second portion of a positive electrode sheet that is not coated with an active material. Along the Y-axis direction, a plurality of first pole lugs on a battery cell body 310 are led out from the first side surface 311 of the battery cell body 310, and a plurality of first pole lugs are stacked in the thickness direction of the first pole lug group 320. The plurality of first pole lugs include two first end pole lugs a. The two first end pole lugs a are close to opposite sides of the width direction of the battery cell body 310. The two first end pole lugs a and the other first pole lugs located between the two first end pole lugs a are pre-welded by ultrasonic welding and cut to form the first pole lug group 320. The two opposite surfaces of the two first end pole lugs a respectively form the first outer surface 321 and the first inner surface 322 of the first pole lug group 320.

[0080] In this embodiment, the material of the first pole lug can be made of aluminum. The length L1 of the first pole lug group 320 is greater than or equal to 25.5 mm and less than or equal to 29.5 mm. When the first pole lug group 320 is attached to the first adapter 52, the contact area of ​​the first pole lug group 320 to the first adapter 52 is satisfied, thereby satisfying the current flow between the first pole lug group 320 and the first pin 50. It can be explained that the length L1 of the first pole lug group 320 is the distance from the first side surface 311 of the battery body 310 to the first end surface 323 of the first pole lug group 320.

[0081] The first pole lug group 320 also includes a first lead-out section 324, a first attachment section 325 and a first middle section 326. The first middle section 326 is connected to the first lead-out section 324. The first lead-out section 324 is used to be connected to the first side surface 311 of the battery cell body 310 and is electrically conductive with the battery cell body 310. The first attachment section 325 is away from the battery cell body 310. The first attachment section 325 is used to be welded and fixed to the first transition portion 52 and is electrically conductive with the first transition portion 52. The first middle section 326 is used to bend the first pole lug group 320, and the first middle section 326 is connected to the first attachment section 325 at an angle to form an L-shaped structure. In this embodiment, the first lead-out section 324 is formed by a plurality of first pole lugs being inclined in the direction of the central axis of the length direction of the battery cell body 310. The cross-section of the first lead-out section 324 is roughly triangular in shape.

[0082] The first attachment section 325 includes a first inner surface 3251 and a first outer surface 3252. The first inner surface 3251 and the second outer surface 3352 are arranged opposite to each other along the thickness direction of the first attachment section 325. The first inner surface 3251 is used to connect with the first transition portion 52. The first end surface 323 is provided in the first attachment section 325, and connects the first inner surface 3251 and the first outer surface 3252. The first end surface 323 is away from the first middle section 326. In this embodiment, the thickness of the first attachment section 325 is greater than or equal to 1 mm and less than or equal to 2 mm, which not only ensures that the plurality of first pole tabs can be welded through to form a stable first pole tab group 320 when ultrasonic welding is performed, but also ensures good welding between the first attachment section 325 and the first transition portion 52.

[0083] The first middle section 326 includes a first inner side surface 3261 and a first outer side surface 3262. The first inner side surface 3261 and the first outer side surface 3262 are disposed opposite to each other along the thickness direction of the first middle section 326. In this embodiment, the thickness of the first middle section 326 is greater than or equal to 1 mm and less than or equal to 2 mm.

[0084] It should be noted that the first outer surface 3252 of the first attachment section 325 and the first outer side surface 3262 of the first middle section 326 form part of the first outer surface 321 of the first tab group 320. The first inner surface 3251 of the first attachment section 325 and the first inner side surface 3261 of the first middle section 326 form part of the first inner surface 322 of the first tab group 320.

[0085] like Figure 6 As shown, the second tab group 330 includes a second outer surface 331, a second inner surface 332, and a second end surface 333. The second outer surface 331 and the second inner surface 332 are arranged opposite to each other along the thickness direction (i.e., the X-axis direction) of the second tab group 330. The second end surface 333 is connected to the second outer surface 331 and the second inner surface 332. The second end surface 333 is away from the second side surface 312 of the battery cell body 310.

[0086] The second pole lug group 330 includes a plurality of second pole lugs (not shown). In this embodiment, the second pole lug is a positive pole lug, and each second pole lug corresponds to a second portion of a positive electrode sheet that is not coated with active material. Along the Y-axis direction, a plurality of second pole lugs on a battery cell body 310 are led out from the second side surface 312 of the battery cell body 310, and a plurality of second pole lugs are stacked in the thickness direction of the second pole lug group 330. The plurality of second pole lugs include two second end pole lugs b. The two second end pole lugs b are close to the opposite sides of the battery cell body 310 in the width direction, and the two second end pole lugs b are arranged roughly symmetrically about the central axis of the length direction of the battery cell 300. The two second end pole lugs b and the other second pole lugs located between the two second end pole lugs b are pre-welded by ultrasonic welding and cut to form the second pole lug group 330. The two opposite surfaces of the two second end pole lugs b respectively form the second outer surface 331 and the second inner surface 332 of the second pole lug group 330.

[0087] In this embodiment, the material of the second pole lug can be made of copper. The length L2 of the second pole lug group 330 is greater than or equal to 22 mm and less than or equal to 26 mm. When the second pole lug group 330 is attached to the second adapter 62, the contact area of ​​the second pole lug group 330 to the second adapter 62 is satisfied, thereby satisfying the current flow between the second pole lug group 330 and the second pin 60. It can be explained that the length L2 of the second pole lug group 330 is the distance from the second side surface 312 of the battery body 310 to the second end surface 333 of the second pole lug group 330.

[0088] The second pole lug group 330 also includes a second lead-out section 334, a second attachment section 335 and a second middle section 336. The second middle section 336 is connected to the second lead-out section 334. The second middle section 336 is connected to the second attachment section 335 at an angle to form an L-shaped structure. The second lead-out section 334 is used to be connected to the second side surface 312 of the battery cell body 310 and electrically conduct with the battery cell body 310. The second attachment section 335 is away from the battery cell body 310. The second attachment section 335 is used to be welded and fixed to the second transition portion 62 and electrically conduct with the second transition portion 62. The second middle section 336 is used to bend the second pole lug group 330. Among them, in this embodiment, the second lead-out section 334 is formed by a plurality of second pole lugs being inclined in the direction of the central axis of the length direction of the battery cell body 310. The cross-section of the second lead-out section 334 is roughly triangular in shape.

[0089] The second attachment section 335 includes a second inner surface 3351 and a second outer surface 3352. The second inner surface 3351 and the second outer surface 3352 are arranged opposite to each other along the thickness direction of the second attachment section 335. The second inner surface 3351 is used to connect with the second transition portion 62. The second end surface 333 is provided in the second attachment section 335, and connects the second inner surface 3351 and the second outer surface 3352. The second end surface 333 is away from the second middle section 336. In this embodiment, the thickness of the second attachment section 335 is greater than or equal to 1 mm and less than or equal to 2 mm, which not only ensures that the plurality of second pole tabs can be welded through to form a stable second pole tab group 330 when ultrasonic welding is performed, but also ensures good welding between the second attachment section 335 and the second transition portion 62.

[0090] The second middle section 336 includes a second inner side surface 3361 and a second outer side surface 3362. The second inner side surface 3361 and the second outer side surface 3362 are disposed opposite to each other along the thickness direction of the second middle section 336. In this embodiment, the thickness of the second middle section 336 is greater than or equal to 1 mm and less than or equal to 2 mm.

[0091] It should be noted that the second outer surface 3352 of the second attachment section 335 and the second outer side surface 3362 of the second middle section 336 form part of the second outer surface 331 of the second tab group 330. The second inner surface 3351 of the second attachment section 335 and the second inner side surface 3361 of the second middle section 336 form part of the second inner surface 332 of the second tab group 330.

[0092] In this embodiment, when the first tab group 320 and the second tab group 330 are at the same welding power, the number of positive tabs of the first tab group 320 is equal to the number of negative tabs of the second tab group 330, or the number of positive tabs of the first tab group 320 is not equal to the number of negative tabs of the second tab group 330. It can be understood that the number of positive tabs of the first tab group 320 and the number of negative tabs of the second tab group 330 can be reasonably matched according to the actual welding power to accommodate the situation where the number of first tabs of the first tab group 320 and the number of second tabs of the second tab group 330 are different, to ensure that the multiple first tabs constituting the first tab group 320 can be welded through, to improve the connection reliability between the first tab group 320 and the first pin 50, and at the same time, to ensure that the multiple second tabs constituting the second tab group 330 can be welded through, to improve the connection reliability between the second tab group 330 and the second pin 60.

[0093] Please also read Figure 5 , Figure 6 and Figure 7 , Figure 7 for Figure 3 The schematic diagram of the cross-section structure of part of the energy storage device shown is shown in FIG. Figure 7The assembly structure of the battery cell and the first pin and the second pin is indicated, but does not refer to the assembly order of the components in the energy storage device, and Figure 7 The first electrode tab group and the second electrode tab group are both in a bent state.

[0094] The first pin 50 and the second pin 60 are both mounted on the battery cell 300. The first tab group 320 is bent and attached to the first transfer portion 52 of the first pin 50, and the second tab group 330 is bent and attached to the second transfer portion 62 of the second pin 60.

[0095] Specifically, the first adapter portion 52 is stacked on the first side surface 311 of the cell body 310, and the first adapter inner surface 521 of the first adapter portion 52 faces the first lead-out section 324, and the first adapter inner surface 521 is spaced from the first side surface 311 to prevent a short circuit between the cell body 310 and the first pin 50. The first adapter outer surface 522 of the first adapter portion 52 faces away from the first side surface 311 of the cell body 310.

[0096] like Figure 7 As shown, the two first tab groups 320 are respectively located on opposite sides of the width direction (i.e., the X-axis direction) of the first transition portion 52. Each first tab group 320 is led out from the first side surface 311 of a battery cell body 310 and bent toward the first transition portion 52. The first attachment sections 325 of the two bent first tab groups 320 extend relatively along the X-axis direction, and the first end surfaces 323 of the two first tab groups 320 are relatively and spaced. The two first attachment sections 325 are both attached to the first transition portion 52, and the first inner surfaces 3251 of the two first attachment sections 325 are both connected to the first transition outer surface 522 of the first transition portion 52. The two first attachment sections 325 are connected to the first transition portion 52 by laser welding and are electrically conductive, so as to increase the current flow path between the first tab group 320 and the first transition portion 52, which is conducive to dispersing the heat generated when the current flows between the first tab group 320 and the first transition portion 52.

[0097] It can be understood that the two first tab groups 320 cover and connect the first transition portion 52, and the two first tab groups 320 and the first transition portion 52 have an overlapping portion. Specifically, the straight-line distance between the first outer side surface 3262 of the first middle section 326 and the central axis HH in the length direction of the battery cell 300 is D1. The width of the overlapping portion of the first transition portion 52 and each first attachment section 325 in the width direction of the battery cell 300 is D2, that is, the straight-line distance between the first surface 523 of the first transition portion 52 and the first end surface 323 of the first attachment section 325 adjacent to the first surface 523 is D2. Among them, the first surface 523 and the first end surface 323 are both located on the same side of the central axis HH in the length direction of the battery cell 300. The ratio of D2 to D1 is greater than or equal to 5 / 7 and less than or equal to 6 / 7, which not only avoids the first attachment sections 325 of the two first tab groups 320 from overlapping in the Y-axis direction, but also ensures that the contact area between the first tab group 320 and the first transition portion 52 can meet the current overcurrent, so as to avoid the contact area between the first tab group 320 and the first transition portion 52 being too small, resulting in excessive local heating of the first transition portion 52, thereby reducing the influence of heat on the first pin 50.

[0098] The second adapter portion 62 is stacked on the second side surface 312 of the cell body 310, and the second adapter inner surface 621 of the second adapter portion 62 faces the second lead-out section 334, and the second adapter inner surface 621 is spaced from the second side surface 312 to prevent a short circuit between the cell body 310 and the second pin 60. The second adapter outer surface 622 of the second adapter portion 62 faces away from the second side surface 312 of the cell body 310.

[0099] like Figure 7 As shown, the two second pole lug groups 330 are respectively located on opposite sides of the width direction (i.e., the X-axis direction) of the second transition portion 62. Each second pole lug group 330 is led out from the second side surface 312 of a battery cell body 310 and bent toward the second transition portion 62. The second attachment sections 335 of the two bent second pole lug groups 330 extend toward each other along the X-axis direction, and the second end surfaces 333 of the two second pole lug groups 330 are opposite and spaced. The two second attachment sections 335 are both attached to the second transition portion 62, and the second inner surfaces 3351 of the two second attachment sections 335 are both connected to the second transition outer surface 622 of the second transition portion 62. The two second attachment sections 335 are connected to the second transition portion 62 by laser welding and are electrically conductive, so as to increase the current flow path between the second pole lug group 330 and the second transition portion 62, which is conducive to dispersing the heat generated when the current flows between the second pole lug group 330 and the second transition portion 62.

[0100] It can be understood that the two second tab groups 330 cover and connect the second transition portion 62, and the two second tab groups 330 and the second transition portion 62 have an overlapping portion. Specifically, the straight-line distance between the second outer side surface 3362 of the second middle section 336 and the central axis HH in the length direction of the battery cell 300 is D3. The width of the overlapping portion of the second transition portion 62 and each second attachment section 335 in the width direction of the battery cell 300 is D4, that is, the straight-line distance between the second surface 623 of the second transition portion 62 and the second end surface 333 of the second attachment section 335 adjacent to the second surface 623 is D4. Among them, the second surface 623 and the second end surface 333 are both located on the same side of the central axis HH in the length direction of the battery cell 300. The ratio of D3 to D4 is greater than or equal to 4 / 7 and less than or equal to 5 / 7, which not only avoids the second attachment sections 335 of the two second tab groups 330 from overlapping in the Y-axis direction, but also ensures that the contact area between the second tab group 330 and the second adapter part 62 can meet the current overcurrent, so as to avoid the contact area between the second tab group 330 and the second adapter part 62 being too small, resulting in excessive local heating of the second adapter part 62, thereby reducing the influence of heat on the second pin 60.

[0101] It can be understood that the influence of heat on the first pin 50 and the second pin 60 is reduced, which is conducive to ensuring the temperature consistency and service life consistency of the first pin 50 and the second pin 60.

[0102] In addition, the design of the width of the contact portion between the first tab group 320 and the first adapter 52 avoids the first tab group 320 being too long and increasing the manufacturing cost of the first tab group 320. At the same time, the design of the width of the contact portion between the second tab group 330 and the second adapter 62 avoids the second tab group 330 being too long and increasing the manufacturing cost of the second tab group 330.

[0103] In this embodiment, the two first electrode tab groups 320 expose a portion of the first transfer portion 52 , and the two second electrode tab groups 330 expose a portion of the second transfer portion 62 .

[0104] It should be noted that along the X-axis direction, the two battery cell bodies 310 are arranged side by side, and the opposing surfaces of the two battery cell bodies 310 are the same side. The surface of the first end pole ear a farthest from the same side before pre-welding is the first outer surface 321, and the partial surface of the first end pole ear a farthest from the same side after pre-welding is the first outer side surface 3262 of the first pole ear group 320, and the straight-line distance from the position of the first outer surface 321 to the position of the first outer side surface 3262 of the first middle section 326 is S1, and the straight-line distance S1 is less than the length of the first end pole ear a. It can be understood that the first end pole ear a farthest from the same side before pre-welding falls down and is welded with the remaining first pole ears, and the distance from the position of the first end pole ear a before pre-welding to the position welded with the remaining first pole ears after pre-welding is less than the length of the first end pole ear a, so that the length of the first end pole ear a can meet the requirements of being welded with the remaining first pole ears to form the first middle section 326 of the first pole ear group 320, avoiding the situation where the current overcurrent of the formed first pole ear group 320 and the first pin 50 is inconsistent due to inconsistent lengths of multiple first pole ears, and ensuring that multiple first pole ears constituting a first pole ear group 320 can be welded and combined and electrically connected to the first pin 50.

[0105] At the same time, along the X-axis direction, the surface of the second end pole lug b that is farthest from the same side before pre-welding is the second outer side 331, and the partial surface of the second end pole lug b that is farthest from the same side after pre-welding is the second outer side surface 3362 of the second pole lug group 330, and the straight-line distance from the position of the second outer side surface 331 to the position of the second outer side surface 3362 of the second middle section 336 is S3, and the straight-line distance S3 is less than the length of the second end pole lug b. It can be understood that the second end pole lug b farthest from the same side before pre-welding falls down and is welded with the remaining second pole lugs, and the distance from the position of the second end pole lug b before pre-welding to the position welded with the remaining second pole lugs after pre-welding is less than the length of the second end pole lug b, so that the length of the second end pole lug b can meet the requirements of being welded with the remaining second pole lugs to form the second middle section 336 of the second pole lug group 330, avoiding the situation where the current overcurrent of the formed second pole lug group 330 and the second pin 60 is inconsistent due to inconsistent lengths of multiple second pole lugs, and ensuring that multiple second pole lugs constituting a second pole lug group 330 can be welded and combined and electrically connected to the second pin 60.

[0106] It can be understood that the condition that the straight-line distance S1 is less than the length of the first end pole ear a is satisfied, and at the same time, the condition that the straight-line distance S3 is less than the length of the second end pole ear b is satisfied, so that the current overcurrent of the first pole ear group 320 and the first pin 50 and the current overcurrent of the second pole ear group 330 and the second pin 60 are consistent, which is conducive to the service life of the first pin 50 and the second pin 60 being consistent, and further conducive to the consistency of the energy storage device 1000.

[0107] In this embodiment, since the first pin 50 is made of aluminum and the second pin 60 is made of copper, the first tab group 320 is matched with the first pin 50, and the second tab group 330 is matched with the second pin 60. The material of the first tab group 320 is the same as that of the first pin 50, and the material of the second tab group 330 is the same as that of the second pin 60. However, the conductivity of copper is higher than that of aluminum, and the heat generation coefficient of copper is lower than that of aluminum. Therefore, there is a difference between the conductivity of the first pin 50 and the conductivity of the second pin 60. The sizes of the first pin 50 and the second pin 60 are designed to be unequal, that is, the size of the first adapter 52 is unequal to the size of the second adapter 62, and the size of the first connection portion 51 is unequal to the size of the second connection portion 61, so as to reduce the difference between the conductivity of the first pin 50 and the conductivity of the second pin 60.

[0108] See also Figure 8 and Fig. 9 , Figure 8 for Figure 2 A side view of a portion of the structure of the energy storage device shown, Fig. 9 for Figure 8 The schematic diagram of the cross-section structure of part of the energy storage device shown is shown. It should be noted that Figure 8 The dotted line in FIG. 1 shows the boundary line between the first ultrasonic welding zone and the first laser welding zone. Fig. 9 The dotted line in the figure shows the boundary line between the second ultrasonic welding zone and the second laser welding zone. Figure 8 and Fig. 9 The housing is not shown in the figures.

[0109] The first pole tab group 320 also includes a first ultrasonic welding area 327 and a first laser welding area 328. The first ultrasonic welding area 327 and the first laser welding area 328 are both located in the first attachment section 325. The first ultrasonic welding area 327 is an area where multiple first pole tabs are ultrasonically welded. The first laser welding area 328 is an area where the first attachment section 325 and the first transition portion 52 are laser welded. The first laser welding area 328 is completely located in the first ultrasonic welding area 327. That is, the orthographic projection of the first laser welding area 328 on the first attachment section 325 is completely located in the first ultrasonic welding area 327. The first laser welding area 328 completely covers the first transition portion 52. The shape of the first ultrasonic welding area 327 can be, but is not limited to, a long rectangular strip, an ellipse, etc. The shape of the first laser welding area 328 can be, but is not limited to, a long rectangular strip, an ellipse, etc. In this embodiment, the number of first ultrasonic welding areas 327 is four, and every two first ultrasonic welding areas 327 are located in one first pole tab group 320. The two first ultrasonic welding areas 327 located in a first tab group 320 are arranged at intervals along the Z-axis direction. The number of the first laser welding areas 328 is two. Each first laser welding area 328 is located in a first tab group 320. The first laser welding area 328 is close to the lower plastic 20. The first ultrasonic welding area 327 and the first laser welding area 328 are both long rectangular strips.

[0110] The first ultrasonic welding area 327 has two first long sides 3271 and two first wide sides 3272. The two first long sides 3271 are arranged opposite to each other along the width direction (i.e., the X-axis direction) of the first ultrasonic welding area 327. The two first wide sides 3272 are arranged opposite to each other along the length direction (i.e., the Z-axis direction) of the first ultrasonic welding area 327. The two first long sides 3271 are connected to the two first wide sides 3272.

[0111] The first laser welding area 328 has two first short sides 3281 and two first narrow sides 3282. The two first short sides 3281 are arranged opposite to each other along the width direction (i.e., the X-axis direction) of the first laser welding area 328. The two first narrow sides 3282 are arranged opposite to each other along the length direction (i.e., the Z-axis direction) of the first laser welding area 328. The two first short sides 3281 are connected to the two first narrow sides 3282.

[0112] In this embodiment, the ratio of the area of ​​the first ultrasonic welding zone 327 to the area of ​​the first laser welding zone 328 is greater than or equal to 0.06 and less than or equal to 0.44. The spacing M1 between a first long side 3271 of the first ultrasonic welding zone 327 and a first short side 3281 of the first laser welding zone 328 adjacent to the first long side 3271 is greater than or equal to 2 mm and less than or equal to 5 mm. At the same time, the spacing N1 between a first wide side 3272 of the first ultrasonic welding zone 327 and a first narrow side 3282 of the first laser welding zone 328 adjacent to the first wide side 3272 is greater than or equal to 1 mm and less than or equal to 2 mm. It can be understood that the area of ​​the first laser welding zone 328 is smaller than the area of ​​the first ultrasonic welding zone 327, which prevents the laser energy generated during the laser welding of the first attachment section 325 and the first adapter portion 52 from being incident on the first outer surface 3262, thereby avoiding the laser energy from being reflected by the smooth surface, reducing the waste of laser energy, and ensuring the welding effect of the first tab group 320 and the first pin 50 during laser welding.

[0113] See also Fig.10 and Fig.11 , Fig.10 for Figure 2 A side view of a portion of the energy storage device shown at another angle, Fig.11 for Fig.10 The schematic diagram of the cross-sectional structure of part of the energy storage device shown in FIG. Fig.10 and Fig.11 The housing is not shown in the figures.

[0114] The second pole tab group 330 also includes a second ultrasonic welding area 337 and a second laser welding area 338. The second ultrasonic welding area 337 and the second laser welding area 338 are both located in the second attachment section 335. The second ultrasonic welding area 337 is the area where multiple second pole tabs are ultrasonically welded. The second laser welding area 338 is the area where the second attachment section 335 and the second transition portion 62 are laser welded. The second laser welding area 338 is completely located in the second ultrasonic welding area 337. That is, the orthographic projection of the second laser welding area 338 on the second attachment section 335 is completely located in the second ultrasonic welding area 337. The second laser welding area 338 completely covers the second transition portion 62. The shape of the second ultrasonic welding area 337 can be, but not limited to, a long rectangular strip, an ellipse, etc. The shape of the second laser welding area 338 can be, but not limited to, a long rectangular strip, an ellipse, etc. In this embodiment, the number of second ultrasonic welding areas 337 is four, and every two second ultrasonic welding areas 337 are located in one second pole tab group 330. The two second ultrasonic welding areas 337 located in a second tab group 330 are arranged at intervals along the Z-axis direction. The number of the second laser welding areas 338 is two. Each second laser welding area 338 is located in a second tab group 330. The second laser welding area 338 is close to the lower plastic 20. The second ultrasonic welding area 337 and the second laser welding area 338 are both long rectangular strips.

[0115] The second ultrasonic welding area 337 has two second long sides 3371 and two second wide sides 3372. The two second long sides 3371 are arranged opposite to each other along the width direction (i.e., the X-axis direction) of the second ultrasonic welding area 337. The two second wide sides 3372 are arranged opposite to each other along the length direction (i.e., the Z-axis direction) of the second ultrasonic welding area 337. The two second long sides 3371 are connected to the two second wide sides 3372.

[0116] The second laser welding area 338 has two second short sides 3381 and two second narrow sides 3382. The two second short sides 3381 are arranged opposite to each other along the width direction (i.e., the X-axis direction) of the second laser welding area 338. The two second narrow sides 3382 are arranged opposite to each other along the length direction (i.e., the Z-axis direction) of the second laser welding area 338. The two second short sides 3381 are connected to the two second narrow sides 3382.

[0117] In this embodiment, the ratio of the area of ​​the second ultrasonic welding zone 337 to the area of ​​the second laser welding zone 338 is greater than or equal to 0.06 and less than or equal to 0.44. Among them, the spacing M2 between a second long side 3371 of the second ultrasonic welding zone 337 and a second short side 3381 of the second laser welding zone 338 adjacent to the second long side 3371 is greater than or equal to 2 mm and less than or equal to 5 mm. At the same time, the spacing N2 between a second wide side 3372 of the second ultrasonic welding zone 337 and a second narrow side 3382 of the second laser welding zone 338 adjacent to the second wide side 3372 is greater than or equal to 1 mm and less than or equal to 2 mm. It can be understood that the area of ​​the second laser welding zone 338 is smaller than the area of ​​the second ultrasonic welding zone 337, which prevents the laser energy generated during the laser welding of the second attachment section 335 and the second adapter portion 62 from being incident on the second outer surface 3362, thereby avoiding the laser energy from being reflected by the smooth surface, reducing the waste of laser energy, and ensuring the welding effect of the second tab group 330 and the second pin 60 during laser welding.

[0118] Combined Figure 3 As shown, the first pole 30, the second pole 40, the first pin 50, the second pin 60 and the lower plastic 20 are installed together on the end cover 10 to form an end cover assembly 100. In the Z-axis direction, the upper surface 21 of the lower plastic 20 is connected to the bottom surface 12 of the end cover 10. The first connecting portion 51 and the second connecting portion 61 are both connected to the lower surface 22 of the lower plastic 20. The first adapter portion 52 and the second adapter portion 62 both extend in a direction away from the lower plastic 20.

[0119] Along the Z-axis direction, the first through hole 13 of the end cover 10, the first pole through hole 23 of the lower plastic 20, and the first through hole 511 of the first connecting portion 51 are coaxially arranged, and the first pole 30 is penetrated through the first through hole 13, the first pole through hole 23, and the first through hole 511, and is welded to the hole wall of the first through hole 511 to achieve electrical conduction between the first pole 30 and the first pin 50. Along the Z-axis direction, the second through hole 14 of the end cover 10, the second pole through hole 24 of the lower plastic 20, and the second through hole 611 of the second connecting portion 61 are coaxially arranged, and the second pole 40 is penetrated through the second through hole 14, the second pole through hole 24, and the second through hole 611, and is welded to the hole wall of the second through hole 611 to achieve electrical conduction between the second pole 40 and the second pin 60. The first pole 30 and the second pole 40 are both insulated and sealed from the end cover 10 by an insulating member (not shown), which not only prevents the first pole 30 and the second pole 40 from being short-circuited with the end cover 10 respectively, but also prevents the electrolyte inside the energy storage device 1000 from flowing out of the energy storage device 1000.

[0120] The end cap assembly 100 is mounted on the battery cell 300. The lower surface 22 of the lower plastic 20 faces the battery cell 300. Along the Z-axis direction, the first connection portion 51 and the second connection portion 61 are spaced apart from the battery cell body 310 to avoid the first connection portion 51 and the second connection portion 61 being connected to the battery cell body 310 and causing a short circuit. The first adapter portion 52 is stacked with the first pole lug group 320 and welded by laser welding to achieve electrical conduction between the first pin 50 and the first pole lug group 320, thereby achieving electrical conduction between the battery cell 300 and the first pole column 30. The second adapter portion 62 is stacked with the second pole lug group 330 and welded by laser welding to achieve electrical conduction between the first pin 50 and the first pole lug group 320, thereby achieving electrical conduction between the battery cell 300 and the second pole column 40.

[0121] The end cap assembly 100 and the battery cell 300 are both installed in the housing 200 , and the edge of the end cap 10 is connected to the edge of the opening 201 of the housing 200 by welding or other means to seal the energy storage device 1000 .

[0122] In the related art, due to the different materials of the positive electrode pin and the negative electrode pin, the conductivity of the positive electrode pin and the conductivity of the negative electrode pin are different. When the size of the positive electrode pin and the negative electrode pin is set to be the same and the size of the positive electrode ear and the negative electrode ear is also set to be the same, that is, the contact area of ​​the positive electrode ear to the positive electrode pin is equal to the contact area of ​​the negative electrode ear to the negative electrode pin, therefore, there is a difference in the current overcurrent capacity of the negative electrode pin and the positive electrode pin. For example, in the case where both the positive electrode pin and the negative electrode pin meet the current overcurrent, the negative electrode pin will have a problem of excess material, thereby reducing the material utilization rate of the negative electrode pin, which is not conducive to the consistency of the energy storage device 1000. Alternatively, in the case where the negative electrode pin just meets the current overcurrent, the positive electrode pin with the same size as the negative electrode pin will be subjected to higher heat when the current is overcurrent. As the battery cell 300 is repeatedly charged and discharged, the service life of the positive electrode pin is generally lower than that of the negative electrode pin, which reduces the consistency of the energy storage device 1000.

[0123] In the embodiment of the present application, the first pin 50 and the second pin 60 have different sizes, and the first tab group 320 and the second tab group 330 also have different sizes. Therefore, under the requirement of current overcurrent between the first tab group 320 and the first pin 50, the width of the contact portion between the first tab group 320 and the first pin 50 is different. At the same time, under the requirement of current overcurrent between the second tab group 330 and the second pin 60, the width of the contact portion between the second tab group 330 and the second pin 60 is also different, which solves the problem of the difference in current overcurrent capacity between the first pin 50 and the second pin 60, makes the service life of the first pin 50 and the second pin 60 tend to be consistent, and also solves the problem of low material utilization of the first pin 50 and the second pin 60, which is conducive to the consistency of the first pin 50 and the second pin 60, and then to the consistency of the energy storage device 1000.

[0124] The above are only some embodiments and implementation methods of the present application, and the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An energy storage device, characterized in that: include: a housing, the housing comprising an opening; A battery cell, the battery cell is installed in the shell, the battery cell comprises a battery cell body, a first pole lug group and a second pole lug group, the battery cell body comprises a first side surface and a second side surface, the first side surface and the second side surface are arranged opposite to each other along the length direction of the battery cell body, the first pole lug group is led out from the first side surface, and the second pole lug group is led out from the second side surface; An end cap assembly, the end cap assembly is mounted at one end of the battery cell and sealed at the opening, the end cap assembly includes a first pin and a second pin, the first pin includes a first transition portion, the first transition portion is overlapped on the first side, the first tab group covers and connects the first transition portion, and the first tab group and the first transition portion have an overlapped portion, the second pin includes a second transition portion, the second transition portion is overlapped on the second side, the second tab group covers and connects the second transition portion, and the second tab group and the second transition portion have an overlapped portion, and the size of the first transition portion is not equal to the size of the second transition portion; The first tab group includes a first outer side surface, the first outer side surface faces away from the first transition portion, a straight-line distance between the first outer side surface and the central axis of the battery cell in the length direction is D1, and a width of a portion where the first tab group and the first transition portion overlap in the width direction of the battery cell is D2, wherein a ratio of D2 to D1 is greater than or equal to 5 / 7 and less than or equal to 6 / 7; The second pole lug group includes a second outer side surface, the second outer side surface is opposite to the second transition portion, the straight-line distance between the second outer side surface and the central axis in the length direction of the battery cell is D3, and the width of the overlapping portion of the second pole lug group and the second transition portion in the width direction of the battery cell is D4, wherein the ratio of D4 to D3 is greater than or equal to 4 / 7 and less than or equal to 5 / 7.

2. The energy storage device according to claim 1, characterized in that: The first pole tab group includes a plurality of first pole tabs, the plurality of first pole tabs are stacked along the thickness direction of the first pole tab group, the plurality of first pole tabs are pre-welded by ultrasonic welding and cut to form the first pole tab group, and the second pole tab group includes a plurality of second pole tabs, the plurality of second pole tabs are stacked along the thickness direction of the second pole tab group, the plurality of second pole tabs are pre-welded by ultrasonic welding and cut to form the second pole tab group; When the first electrode tab group and the second electrode tab group are under the same welding power, the number of the first electrode tabs and the number of the second electrode tabs are not equal.

3. The energy storage device according to claim 2, characterized in that: The first electrode tab comprises a first end electrode tab, a surface of the first end electrode tab before pre-welding is a first outer surface, a part of the surface of the first end electrode tab after pre-welding is the first outer side surface of the first electrode tab group, and a straight-line distance from the first outer surface to the first outer side surface is less than a length of the first end electrode tab; The second pole lug includes a second end pole lug, the surface of the second end pole lug before pre-welding is the second outer surface, and a portion of the surface of the second end pole lug after pre-welding is the second outer side surface of the second pole lug group, and a straight-line distance from the position of the second outer surface to the position of the second outer side surface is less than the length of the second end pole lug.

4. The energy storage device according to claim 1, characterized in that: The number of the first electrode tab groups is two, the two first electrode tab groups are respectively located on opposite sides of the width direction of the first transition portion and are bent toward the first transition portion, each of the first electrode tab groups includes a first attachment section, the two first attachment sections extend relatively along the width direction of the first transition portion and are both attached to the surface of the first transition portion facing away from the first side surface, and the first attachment section is connected to the first transition portion by laser welding; There are two second pole lug groups, the two second pole lug groups are respectively located on opposite sides of the width direction of the second transition portion and are bent toward the second transition portion, each second pole lug group includes a second attachment section, the two second attachment sections extend toward each other along the width direction of the second transition portion and are both attached to the surface of the second transition portion facing away from the second side surface, and the second attachment section is connected to the second transition portion by laser welding.

5. The energy storage device according to claim 4, characterized in that: Each of the first tab groups further includes a first lead-out section and a first middle section, the first lead-out section is connected to the first side surface and is electrically connected to the battery cell body, the first middle section is connected to the first lead-out section and is connected to the first attachment section at an angle, the first middle section has the first outer side surface, the first transition portion includes a first transition inner surface, the first transition inner surface faces the first lead-out section and is spaced from the first side surface; Each of the first electrode tab groups also includes a second lead-out section and a second middle section, the second lead-out section is connected to the second side surface and is electrically conductive with the battery cell body, the second middle section is connected to the second lead-out section and is connected at an angle to the second attachment section, the second middle section has the second outer side surface, and the second transition portion includes a second transition inner surface, the second transition inner surface faces the second lead-out section and is spaced from the second side surface.

6. The energy storage device according to claim 4, characterized in that: The thickness of the first attachment section is greater than or equal to 1 mm and less than or equal to 2 mm; The thickness of the second attachment section is greater than or equal to 1 mm and less than or equal to 2 mm.

7. The energy storage device according to claim 4, characterized in that: The first tab group includes a first ultrasonic welding area and a first laser welding area, the first ultrasonic welding area and the first laser welding area are both located in the first attachment section, the first laser welding area is completely located in the first ultrasonic welding area, the ratio of the area of ​​the first laser welding area to the area of ​​the first ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the first laser welding area completely covers the first transition portion; The second tab group includes a second ultrasonic welding area and a second laser welding area, the second ultrasonic welding area and the second laser welding area are both located in the second attachment section, the second laser welding area is completely located in the second ultrasonic welding area, the ratio of the area of ​​the second laser welding area to the area of ​​the second ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the second laser welding area completely covers the second transition portion.

8. The energy storage device according to claim 7, characterized in that: The first laser welding area includes a first short side and a first narrow side, the first ultrasonic welding area includes a first long side and a first wide side, the first long side is parallel to the first short side, and the spacing between the first long side and the adjacent first short side is greater than or equal to 2 mm and less than or equal to 5 mm, the first wide side is parallel to the first narrow side, and the spacing between the first wide side and the adjacent first narrow side is greater than or equal to 1 mm and less than or equal to 2 mm; The second laser welding area includes a second short side and a second narrow side, the second ultrasonic welding area includes a second long side and a second wide side, the second long side is parallel to the second short side, and the spacing between the second long side and the adjacent second short side is greater than or equal to 2 mm and less than or equal to 5 mm, the second wide side is parallel to the second narrow side, and the spacing between the second wide side and the adjacent second narrow side is greater than or equal to 1 mm and less than or equal to 2 mm.

9. The energy storage device according to any one of claims 1 to 8, characterized in that: The length of the first tab group is greater than or equal to 25.5 mm and less than or equal to 29.5 mm; The length of the second tab group is greater than or equal to 22 mm and less than or equal to 26 mm.

10. An electrical device, characterized in that: It comprises an energy storage device as described in any one of claims 1 to 9, and the energy storage device supplies power to the electrical equipment.

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