Lower plastic, end cover assembly, energy storage device and energy storage system

Abstract

The embodiment of the invention provides lower plastic, an end cover assembly, an energy storage device and an energy storage system. The lower plastic is used for the energy storage device and comprises a body, a plurality of first limiting protrusions and a plurality of second limiting protrusions, the body comprises a first surface and a second surface which are arranged back to back, and the first limiting protrusions and the second limiting protrusions are all arranged on the second surface of the body in a protruding mode. The multiple first limiting protrusions are arranged in the width direction of the lower plastic at intervals, the multiple second limiting protrusions are arranged in the width direction of the lower plastic at intervals, and the multiple first limiting protrusions and the multiple second limiting protrusions are arranged at the two ends of the length direction of the lower plastic respectively and symmetrically arranged along the central axis of the width direction of the lower plastic. And each first limiting bulge is matched with one second limiting bulge so as to support and limit a battery cell of one energy storage device. According to the technical scheme, gas generated in the thermal runaway process of the energy storage device can be rapidly exhausted, shell explosion is prevented, and the safety of the energy storage device is improved.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a lower plastic, an end cap assembly, an energy storage device, and an energy storage system. Background Technology

[0002] With the development of energy storage technology, users have increasingly higher requirements for the safety performance of energy storage devices. However, in pursuit of higher energy density, existing energy storage devices have limited internal channels for gas venting. When an energy storage device experiences thermal runaway, the cells rapidly generate a large amount of gas inside the device that cannot be vented in time. This gas can easily accumulate inside the device, leading to problems such as casing explosion, seriously affecting the safety of the energy storage device. Summary of the Invention

[0003] This application provides a lower plastic, an end cap assembly, an energy storage device, and an energy storage system, which can meet the requirement of rapid discharge of gas generated during thermal runaway of the energy storage device, prevent the casing from exploding, and improve the safety of the energy storage device.

[0004] In a first aspect, embodiments of this application provide a lower plastic material. The lower plastic material is used in an energy storage device, and the lower plastic material comprises:

[0005] The body includes a first surface and a second surface, the first surface and the second surface being disposed opposite to each other along the thickness direction of the body;

[0006] Multiple first limiting protrusions and multiple second limiting protrusions;

[0007] Multiple first limiting protrusions and multiple second limiting protrusions are provided on the second surface of the body. The multiple first limiting protrusions are located at one end of the lower plastic along its length direction and are spaced apart in the lower plastic along its width direction. The multiple second limiting protrusions are located at the other end of the lower plastic along its length direction and are spaced apart in the lower plastic along its width direction. The multiple first limiting protrusions and multiple second limiting protrusions are symmetrically arranged along the central axis of the lower plastic along its width direction. Each first limiting protrusion and each second limiting protrusion cooperate to support and limit the battery cell of one of the energy storage devices.

[0008] In one embodiment, the lower plastic further includes two end ribs, both of which protrude from the second surface of the body and are located at both ends of the body in the length direction. Each end rib includes a main body segment and two extension segments. The main body segment is connected to one side edge of the body in the length direction of the lower plastic and extends along the width of the lower plastic. The two extension segments are connected to opposite ends of the main body segment in the width direction of the lower plastic and to both sides of the body in the width direction of the lower plastic, and extend along the length direction of the lower plastic to the other end of the lower plastic.

[0009] The plurality of first limiting protrusions are all connected to the main body segment of one of the end ribs, and the plurality of second limiting protrusions are all connected to the main body segment of another end rib.

[0010] In one embodiment, each of the end ribs has a heat-melting point on its main body segment and two extension segments.

[0011] In one embodiment, the lower plastic further includes a plurality of first reinforcing ribs, each of which protrudes from the second surface of the body. Each first reinforcing rib is connected to a main body segment of one of the end ribs, and the first reinforcing ribs are correspondingly arranged with the hot melt points on the main body segment.

[0012] In one embodiment, the lower plastic further includes a plurality of second reinforcing ribs, which protrude from the second surface of the body. Each second reinforcing rib is connected to an extension of one of the end ribs, and the second reinforcing ribs are corresponding to the hot melt points on the extensions.

[0013] In one embodiment, the lower plastic further includes a plurality of first guide channels and a plurality of second guide channels. The plurality of first guide channels and the plurality of second guide channels are recessed on the first surface of the body. Each first guide channel protrudes on the second surface of the body to form a first limiting protrusion, and each second guide channel protrudes on the second surface of the body to form a second limiting protrusion.

[0014] In one embodiment, the lower plastic also includes two end faces, which are arranged opposite to each other along the length of the lower plastic. A plurality of first guide grooves pass through one of the end faces, and a plurality of second guide grooves pass through the other end face.

[0015] In one embodiment, the lower plastic further includes two end faces, which are arranged opposite to each other along the length of the lower plastic. A plurality of first guide grooves and one of the end faces are adjacent to and spaced apart, and a plurality of second guide grooves are adjacent to and spaced apart from the other end face.

[0016] The lower plastic also includes a plurality of first guide holes and a plurality of second guide holes. Each first guide hole is disposed on the bottom wall of the first channel of the first guide groove and communicates with the first guide groove. Each second guide hole is disposed on the bottom wall of the second channel of the second guide groove and communicates with the second guide groove.

[0017] Secondly, embodiments of this application provide an end cap assembly. The end cap assembly includes an end cap, a lower plastic component, an explosion-proof valve, and the lower plastic component. The end cap and the body are stacked and connected along the thickness direction of the end cap assembly. Two end ribs, a plurality of first limiting protrusions, and a plurality of second limiting protrusions are all located on the side of the body facing away from the end cap. The explosion-proof valve is mounted on the end cap.

[0018] Thirdly, embodiments of this application provide an energy storage device. The energy storage device includes a battery cell, an insulating film, and an end cap assembly. The end cap assembly is mounted on the top of the battery cell, and the insulating film covers the periphery and bottom of the battery cell, and the insulating film is thermally fused to the lower plastic.

[0019] The insulating film and the periphery of the battery cell form a current-collecting channel. A venting channel is formed between the plurality of first limiting protrusions, the plurality of second limiting protrusions, the two end ribs, the edge of the body, and the periphery of the battery cell. The plurality of first limiting protrusions and the plurality of second limiting protrusions support the battery cell and form a current-collecting space between the body and the battery cell. The venting channel communicates with the current-collecting space and the current-collecting channel. The explosion-proof valve is located within the current-collecting space.

[0020] In one embodiment, the battery cell includes a plurality of bare battery cells, which are arranged side by side along the width direction of the energy storage device;

[0021] In the width direction of the energy storage device, the number of the first limiting protrusion and the second limiting protrusion of the lower plastic are equal to the number of the bare battery cells, and the bare battery cells abut against one of the first limiting protrusions and one of the second limiting protrusions.

[0022] In one embodiment, the ratio of the dimension of the first limiting protrusion or the second limiting protrusion in the lower plastic width direction to the thickness of the bare battery cell is greater than or equal to 0.3 and less than or equal to 0.9.

[0023] In one embodiment, the ratio of the projected area of ​​the exhaust channel to the projected area of ​​the confluence channel along the height direction of the energy storage device is greater than or equal to 0.5.

[0024] Fourthly, embodiments of this application provide an energy storage system. The energy storage system includes the energy storage device.

[0025] In related technologies, existing lower plastic panels have protrusions that abut against the battery cell. These protrusions not only abut against the battery cell but also serve for thermal bonding with the insulating film. These protrusions extend along the width of the lower plastic panel, and their dimensions in this direction are larger than the width of the battery cell. This results in a portion of the protrusion not abutting against the battery cell, rendering it unusable and obstructing venting channels. This limits the design of available channels for gas exhaust within the energy storage device. When the energy storage device experiences thermal runaway, the battery cell rapidly generates a large amount of gas inside the device, which cannot be expelled in time. This gas can easily accumulate inside the energy storage device, leading to problems such as casing explosion, seriously affecting the safety of the energy storage device.

[0026] In this embodiment, multiple first limiting protrusions and multiple second limiting protrusions are respectively provided at both ends of the lower plastic along its length direction. The multiple first limiting protrusions and multiple second limiting protrusions are symmetrically arranged along the central axis of the lower plastic along its width direction. The multiple first limiting protrusions are spaced apart along the width direction of the lower plastic, and the multiple second limiting protrusions are also spaced apart along the width direction of the lower plastic. Each first limiting protrusion and each second limiting protrusion cooperate to not only abut against the top surface of a bare battery cell and limit its movement to prevent large displacement caused by the battery cell's movement, but also support the battery cell, ensuring that the battery cell and the main body are spaced apart. Furthermore, there are gaps between the multiple first limiting protrusions and between the multiple second limiting protrusions. When the multiple first limiting protrusions and the multiple second limiting protrusions abut against the battery cell, they form partial exhaust channels between the edges of the battery cell and the main body, respectively. Compared with the exhaust channels formed by the lower plastic and the battery cell in the prior art, this application increases the projected area of ​​the exhaust channel in the axial direction. When the battery cell experiences thermal runaway and generates a large amount of gas, this exhaust channel can ensure that the gas inside the energy storage device flows into the confluence space in a timely and rapid manner and is discharged from the explosion-proof valve, avoiding the accumulation of gas inside the energy storage device and causing problems such as shell explosion, thereby improving the safety of the energy storage device. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments or background art of this application, the accompanying drawings used in the embodiments or background art of this application will be described below.

[0028] Figure 1 This is a schematic diagram of the structure of an energy storage system according to an embodiment of this application;

[0029] Figure 2 for Figure 1 A schematic diagram of the energy storage device in the energy storage system shown.

[0030] Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device.

[0031] Figure 4 for Figure 3 A schematic diagram of the structure of the end cap assembly of the energy storage device in a first embodiment;

[0032] Figure 5 for Figure 4 The diagram shows the structure of the end cap assembly from another angle;

[0033] Figure 6 for Figure 4 The diagram shows an exploded view of the end cap assembly.

[0034] Figure 7 for Figure 6 The diagram shows the structure of the end cap at another angle;

[0035] Figure 8 for Figure 6 A schematic diagram of the structure of the lower plastic of the end cap assembly shown in the diagram;

[0036] Figure 9 for Figure 6 The diagram shows the structure of the lower plastic at another angle;

[0037] Figure 10 for Figure 4 The diagram shows the structural relationship between the end cap assembly and the battery cell.

[0038] Figure 11 for Figure 10 A bottom perspective view showing the positional relationship between the end cap assembly and the battery cell;

[0039] Figure 12 for Figure 2 The diagram shows a partial cross-section of the energy storage device along AA.

[0040] Figure 13 for Figure 6 A schematic diagram of the structure of the lower plastic of the end cap assembly shown in the second embodiment;

[0041] Figure 14 for Figure 6 A schematic diagram of the structure of the lower plastic of the end cap assembly shown in the third embodiment;

[0042] Figure 15 for Figure 14The diagram shows the structure of the lower plastic at another angle.

[0043] The terms corresponding to the reference numerals in the figures are as follows: Energy storage system 4000, high-voltage cable 4100, first power conversion device 4200, second power conversion device 4300, energy storage device 1000, housing 200, opening 201, receiving cavity 202, end cap assembly 100, end cap 20, first surface 21, second surface 22, through hole 23, pressure relief hole 24, lower plastic 10, end face 101, side face 102, body 11, and so on. Surface 111, second surface 112, side surface 113, pole post through hole 114, explosion-proof part 115, explosion-proof fence 116, explosion-proof boss 117, boss side 118, end rib 12, outer side 121, inner side 122, main body section 123, extension section 124, first guide channel 13, first channel bottom wall 131, first channel side wall 132, first channel end wall 133, first channel opening 13a, third channel opening 13b Second guide channel 14, second channel bottom wall 141, second channel side wall 142, second channel end wall 143, second channel opening 14a, fourth channel opening 14b, first limiting protrusion 15, first limiting surface 151, first limiting side surface 152, second limiting protrusion 16, second limiting surface 161, second limiting side surface 162, first guide hole 17, second guide hole 18, first reinforcing rib a, second reinforcing rib b, pole post assembly 30, pole post 31. Sealing and insulating component; 32. Pressure block; 33. Explosion-proof valve; 40. Battery cell; 300. Bare battery cell; 310. Peripheral side surface; 311. Top surface; 312. Bottom surface; 313. Insulating film; 400. First channel m1; Second channel m2; Third channel m3; Fourth channel m4; Fifth channel m5; Exhaust channel m; Combining space N; Combining channel O; Width W of first limiting protrusion 15 or second limiting protrusion 16; Thickness T of bare battery cell 310. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0045] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly specified. Furthermore, the terms "same," "equal," or "parallel" used below are all allowed to have certain tolerances.

[0046] It should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0047] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form for future applications. Currently, the main way to generate green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels.

[0048] Currently, the generation of green electricity generally relies on solar, wind, and hydropower. However, wind and solar power are characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak hours, and excessive power during off-peak hours. Unstable voltage can also damage the power grid. Therefore, due to insufficient electricity demand or insufficient grid capacity, solving these problems requires energy storage. This involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, this energy can be converted back into electrical energy and released. Simply put, energy storage is like a large "power bank," storing electrical energy when solar and wind power are abundant and releasing the stored electricity when needed.

[0049] Taking electrochemical energy storage as an example, this solution provides an energy storage device for use in energy storage systems. The energy storage device is equipped with a set of chemical batteries, which mainly use the chemical elements in the batteries as energy storage media. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage media. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electricity is released for use, or transferred to places with a shortage of electricity for use.

[0050] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. The corresponding types of energy storage devices include:

[0051] (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can assist renewable energy power generation in meeting grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power regulation power source on the power supply side, energy storage power stations can achieve load matching of power in time and space, enhance the absorption capacity of renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy power generation, and are of great significance in power grid system backup, alleviating peak load power supply pressure and peak regulation and frequency regulation.

[0052] (2) Energy storage containers applied on the grid side mainly function as peak shaving, frequency regulation and grid congestion relief. In terms of peak shaving, they can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak electricity load period, thereby achieving a balance between power production and consumption.

[0053] (3) Small-scale energy storage cabinets applied to the electricity consumption side primarily function to facilitate self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improve power supply reliability. Depending on the application scenario, electricity consumption-side energy storage can be categorized into commercial and industrial energy storage cabinets, residential energy storage devices, and energy storage charging piles, which are generally used in conjunction with distributed photovoltaic systems. Considering that photovoltaic power generation occurs during the day while user loads are typically higher at night, configuring energy storage can better utilize photovoltaic power, improve self-consumption levels, and reduce electricity costs. Furthermore, energy storage is required in communication base stations, data centers, and other fields for backup power.

[0054] In some embodiments, please refer to Figure 1 , Figure 1 This is a schematic diagram of an energy storage system according to an embodiment of this application. Figure 1 The embodiments are illustrated using a shared energy storage scenario on the generation / distribution side as an example. The energy storage device 1000 of this application is not limited to its generation / distribution side energy storage scenario.

[0055] This application provides an energy storage system 4000. The energy storage system 4000 is used to supply power to electrical equipment. The energy storage system 4000 includes: a high-voltage cable 4100, a first power conversion device 4200, a second power conversion device 4300, and the energy storage device 1000 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4300 can be a wind power conversion device. Since the electricity generated by wind power conversion is volatile, random, and intermittent, the unstable electricity output by the wind power conversion device can be stored in the energy storage device 1000 through grid connection. The energy storage device 1000 is connected to the high-voltage cable 4100 and outputs smooth electricity to supply the power consumption side of the distribution network, achieving peak shaving and frequency regulation, and stable grid operation; or, the wind power conversion device initially... Finally, it connects to the high-voltage cable 4100. Under normal power generation conditions, the power output from the wind power conversion device is supplied to the power consumption side of the distribution network via the high-voltage cable. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in the energy storage device 1000, reducing wind and solar curtailment rates and improving the problem of new energy power generation consumption. Furthermore, when the power load is high, the grid issues an instruction to transmit the power stored in the energy storage device 1000, along with the high-voltage cable 4100, in a grid-connected mode to supply power to the power consumption side. This provides various services for grid operation, including peak shaving, frequency regulation, and backup, fully leveraging the grid's peak shaving function, promoting peak shaving and valley filling, and alleviating grid power supply pressure. It can be understood that the energy storage device 1000 in the energy storage system 4000 is used to supply power to electrical equipment.

[0056] In some embodiments on the distribution network side, the first power conversion device 4200 can be a photovoltaic power conversion device. The energy storage device 1000 is connected to the high-voltage cable 4100 and installed downstream of the high-voltage cable 4100 and between the user load. The power output by the photovoltaic power conversion device is stored in the energy storage device 1000, which can respond in a timely manner and act as a backup power source when the power grid / distribution network fails. Alternatively, it can provide power supply support to alleviate line congestion when the high-voltage cable 4100 transmission line is blocked, and to delay the economic pressure caused by the expansion of the power grid / distribution capacity when the power grid is planned to be expanded.

[0057] Optionally, the first power conversion device 4200 may include, but is not limited to, a wind power conversion device, and the second power conversion device 4300 may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 4200 and the second power conversion device 4300 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0058] Optionally, the energy storage device 1000 may include, but is not limited to, energy storage applications such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power supply systems, and may also be applied in multiple fields such as data centers, aerospace, charging piles, and electric vehicles.

[0059] Optionally, the energy storage device 1000 may include, but is not limited to, single-cell batteries, or battery modules, battery packs, battery clusters, power banks, energy storage cabinets / containers, and other battery integrated systems composed of single-cell batteries. The actual application form of the energy storage device 1000 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 1000. This application embodiment only uses a multi-cell battery as an example for illustration.

[0060] Optionally, when the energy storage device 1000 is a single battery cell, the energy storage device 1000 can be, but is not limited to, at least one of cylindrical, square, prismatic, or other shaped batteries.

[0061] Optionally, the battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application does not specifically limit it.

[0062] Please see Figure 2 and Figure 3 , Figure 2 for Figure 1 The diagram shown is a structural schematic of an energy storage device in an energy storage system. Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device.

[0063] For ease of description, the width direction of the energy storage device 1000 is defined as the X-axis, the length direction as the Y-axis, and the height direction as the Z-axis. The X-axis, Y-axis, and Z-axis are all perpendicular to each other.

[0064] The directional terms such as "upper," "lower," "bottom," "top," "right," and "left" mentioned in the embodiments of this application are based on the appendix to the specification. Figure 2 The description is based on the orientation shown. It 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 defined as the top or top of the energy storage device 1000, and the negative direction toward the Z-axis is defined as the bottom or bottom of the energy storage device 1000.

[0065] like Figure 2 and Figure 3 As shown, the energy storage device 1000 includes a housing 200, an end cap assembly 100, a battery cell 300, and an insulating film 400. The housing 200 has an opening 201 and a receiving cavity 202. The opening 201 and the receiving cavity 202 are connected. The battery cell 300 and the insulating film 400 are both housed within the receiving cavity 202. The insulating film 400 is disposed between the battery cell 300 and the housing 200. The insulating film 400 covers the periphery and bottom of the battery cell 300 and exposes the top of the battery cell 300. The insulating film 400 serves to separate and insulate the battery cell 300 from the housing 200, protecting the battery cell 300 and preventing short circuits caused by contact between the battery cell 300 and the housing 200. The end cap assembly 100 is mounted on one side of the battery cell 300 in the height direction (i.e., the Z-axis direction) and seals the opening 201 of the housing 200 to isolate the internal and external environments of the energy storage device 1000.

[0066] The battery cell 300 includes multiple bare cells 310. In this embodiment, there are two bare cells 310, and the two bare cells 310 have approximately the same structure and size. The two bare cells 310 are connected side by side along the X-axis. Each bare cell 310 includes a peripheral side surface 311, a top surface 312, and a bottom surface 313. The top surface 312 and the bottom surface 313 are arranged facing away from each other along the height direction (i.e., the Z-axis direction) of the bare cell 310. The peripheral side surface 311 is connected to the top surface 312 and the bottom surface 313.

[0067] Please refer to the following: Figure 4 , Figure 5 and Figure 6 , Figure 4 for Figure 3 A schematic diagram of the end cap assembly of the energy storage device. Figure 5 for Figure 4 The diagram shown is a structural schematic of the end cap assembly from another angle. Figure 6 for Figure 4 The diagram shows an exploded view of the end cap assembly.

[0068] The end cap assembly 100 includes an end cap 20, a lower plastic component 10, an electrode assembly 30, and an explosion-proof valve 40. The end cap 20 and the lower plastic component 10 are stacked and connected along the thickness direction (i.e., the Z-axis direction) of the end cap assembly 100. The electrode assembly 30 is mounted at one end of the end cap assembly 100 along its length direction (i.e., the Y-axis direction). In this embodiment, there are two electrode assemblies 30, each mounted at one end of the end cap assembly 100 along its length. The explosion-proof valve 40 is mounted on the end cap 20, located between the two electrode assemblies 30, and spaced apart from them. In the event of thermal runaway and a rapid generation of a large amount of gas in the energy storage device 1000, the explosion-proof valve 40 is used to release pressure and gas, preventing the accumulation of a large amount of gas within the energy storage device 1000 and thus preventing an explosion.

[0069] In this embodiment, as Figure 5 and Figure 6 As shown, each electrode assembly 30 includes an electrode 31, a sealing and insulating member 32, and a pressure block 33. The sealing and insulating member 32 is sleeved on the outer periphery of the electrode 31. The electrode 31 passes through the end cap 20 and the lower plastic 10 in sequence, and the electrode 31 is separated from and insulated from the end cap 20 by the sealing and insulating member 32. The pressure block 33 is located on the side of the lower plastic 10 facing away from the end cap 20, and is sleeved on the outer periphery of the portion of the electrode 31 that protrudes from the lower plastic 10.

[0070] In this embodiment, one of the electrode assembly 30 is a positive electrode assembly, which includes a positive electrode post 31 and a positive electrode pressing block 33. The other electrode assembly 30 is a negative electrode assembly, which includes a negative electrode post 31 and a negative electrode pressing block 33. It should be noted that the electrode assembly 30 can also have other structural forms, and this application does not limit them.

[0071] Please refer to the following: Figure 6 and Figure 7 , Figure 7 for Figure 6 The diagram shows the end cap structure at another angle.

[0072] The end cap 20 includes a first surface 21 and a second surface 22. The first surface 21 and the second surface 22 are arranged facing away from each other along the thickness direction (i.e., the Z-axis direction) of the end cap 20. In this embodiment, the end cap 20 is approximately a rectangular plate.

[0073] The end cap 20 also includes two through holes 23. Both through holes 23 penetrate the first surface 21 and the second surface 22 of the end cap 20. The two through holes 23 are located at opposite ends along the length direction (i.e., the Y-axis direction) of the end cap 20. One through hole 23 is used for the positive electrode post to pass through, and the other through hole 23 is used for the negative electrode post to pass through. In this embodiment, both through holes 23 are approximately circular.

[0074] The end cap 20 also includes a pressure relief hole 24. The pressure relief hole 24 extends through the first surface 21 and the second surface 22 of the end cap 20. The pressure relief hole 24 is located between two through holes 23 and is spaced apart from both through holes 23. The pressure relief hole 24 is used to accommodate the explosion-proof valve 40 and to allow the internal gas of the energy storage device 1000 to be discharged to the outside of the energy storage device 1000. In this embodiment, the pressure relief hole 24 is approximately elliptical.

[0075] Please refer to the following: Figure 8 and 9 , Figure 8 for Figure 6 The diagram shows a structural schematic of the lower plastic portion of the end cap assembly according to a first embodiment. Figure 9 for Figure 6 The diagram shows the structure of the lower plastic at another angle.

[0076] In this embodiment, the lower plastic 10 is generally a rectangular plate. The lower plastic 10 includes a body 11. The body 11 includes a first surface 111, a second surface 112, and a side surface 113. The first surface 111 and the second surface 112 are two surfaces of the body 11 arranged opposite to each other in the thickness direction (i.e., the Z-axis direction) of the lower plastic 10. The side surface 113 is connected to the first surface 111 and the second surface 112. The side surface 113 includes two first side surfaces and two second side surfaces. The two first side surfaces are two surfaces of the body 11 arranged opposite to each other in the length direction (i.e., the Y-axis direction) of the lower plastic 10. The two second side surfaces are two surfaces of the body 11 arranged opposite to each other in the width direction (i.e., the X-axis direction) of the lower plastic 10. Both second side surfaces are connected to the two first side surfaces. Alternatively, both the two first side surfaces and the two second side surfaces are connected to the first surface 111 and the second surface 112.

[0077] The body 11 also includes two through holes 114. Both through holes 114 penetrate the first surface 111 and the second surface 112 of the body 11. The two through holes 114 are located at opposite ends along the length of the body 11. One through hole 114 is for the positive electrode to pass through, and the other through hole 114 is for the negative electrode to pass through. In this embodiment, both through holes 114 are approximately circular.

[0078] The main body 11 also includes an explosion-proof section 115. The explosion-proof section 115 is located between the two pole through holes 114 and is spaced apart from both pole through holes 114. The explosion-proof section 115 is used to cooperate with the pressure relief hole 24 of the end cap 20 to provide a discharge channel for gas inside the energy storage device 1000. The explosion-proof section 115 has an explosion-proof grille 116 recessed on the first surface 111 of the main body 11 and an explosion-proof boss 117 protruding on the second surface 112 of the main body 11. The explosion-proof boss 117 includes two boss side surfaces 118. The two boss side surfaces 118 are two surfaces of the explosion-proof boss 117 facing away from each other in the width direction of the lower plastic 10, and the two boss side surfaces 118 are respectively connected to the two second side surfaces of the main body 11. It can be understood that the explosion-proof section 115 includes the explosion-proof boss 117 and the explosion-proof grille 116. In this embodiment, the explosion-proof fence 116 can be considered as a rectangular groove, with multiple vent holes on its bottom wall to allow gas inside the energy storage device 1000 to pass through. The explosion-proof boss 117 is generally a rectangular boss. Hot-melt points (not shown) are respectively provided on the two sides 118 of the explosion-proof boss 117, allowing the explosion-proof boss 117 to be hot-melt connected to the insulating film 400 through these hot-melt points.

[0079] The lower plastic 10 also includes two end ribs 12. Both end ribs 12 protrude from the second surface 112 of the body 11 and are located at both ends of the body 11 along its length. In this embodiment, the two end ribs 12 have the same structure, both being approximately U-shaped protrusions.

[0080] The end rib 12 includes an outer surface 121 and an inner surface 122. The outer surface 121 and the inner surface 122 are arranged opposite to each other along the thickness direction of the end rib 12. The inner surface 122 is connected to the second surface 112 of the body 11 and is arranged at an angle to the second surface 112. The outer surface 121 has the same orientation as the side surface 113 of the body 11, and the outer surface 121 is connected to the side surface 113. In this embodiment, both the outer surface 121 and the inner surface 122 are U-shaped surfaces.

[0081] The end rib 12 also includes a main body segment 123 and two extension segments 124. The two extension segments 124 are respectively connected to opposite ends of the main body segment 123 in the width direction of the lower plastic 10. The main body segment 123 is connected to one edge of the body 11 in the length direction of the lower plastic 10, and extends along the width direction of the lower plastic 10. The two extension segments 124 are respectively connected to opposite sides of the body 11 in the width direction of the lower plastic 10. The two extension segments 124 extend in the same direction. Along the length direction of the lower plastic 10, both extension segments 124 extend from one end in the length direction of the lower plastic 10 to the other end in the length direction of the lower plastic 10. The extension directions of the two extension segments 124 are angled to those of the main body segment 123. The inner surface 122 of the main body segment 123 and the inner surface 122 of the two extension segments 124 are both connected to the second surface 112, and the inner surface 122 of the two extension segments 124 are opposite to and spaced apart in the width direction of the lower plastic 10. The outer surface 121 of the main body segment 123 is connected to a first side surface of the body 11 and together with the first side surface forms an end face 101. The outer surface 121 of each extension segment 124 is connected to a second side surface of the body 11 and together with the second side surface forms a partial side surface 102.

[0082] It is understood that the lower plastic 10 includes two end faces 101 and two side faces 102. The two end faces 101 are arranged opposite to each other along the length direction of the lower plastic 10, and the two side faces 102 are arranged opposite to each other along the width direction of the lower plastic 10. The two end faces 101 and the two side faces 102 are connected.

[0083] In this embodiment, the outer surfaces 121 of the main body segment 123 and the two extension segments 124 are provided with hot melt points (not shown in the figure), and the main body segment 123 and the two extension segments 124 can be hot melt connected to the insulating film 400 through the hot melt points.

[0084] The lower plastic 10 also includes a plurality of first guide channels 13 and a plurality of second guide channels 14. The plurality of first guide channels 13 and the plurality of second guide channels 14 are recessed in the first surface 111 of the body 11. The plurality of first guide channels 13 are respectively provided with a plurality of first limiting protrusions 15 on the second surface 112, and the plurality of second guide channels 14 are respectively provided with a plurality of second limiting protrusions 16 on the second surface 112. The plurality of first guide channels 13 and the plurality of second guide channels 14 are located at opposite ends in the length direction of the lower plastic 10, and are symmetrically arranged along the central axis in the width direction of the lower plastic 10. The plurality of first guide channels 13 are adjacent to and spaced apart from one end face 101 of the lower plastic 10, and are also spaced apart along the width direction of the lower plastic 10. Multiple second guide channels 14 are adjacent to and spaced apart from the other end face 101 of the lower plastic 10, and are spaced apart along the width direction of the lower plastic 10. Correspondingly, multiple first limiting protrusions 15 and multiple second limiting protrusions 16 are located at opposite ends in the length direction of the lower plastic 10, and are symmetrically arranged along the central axis in the width direction of the lower plastic 10. Each of the multiple first limiting protrusions 15 is connected to one end rib 12 of the lower plastic 10, and is spaced apart along the width direction of the lower plastic 10. Each of the multiple second limiting protrusions 16 is connected to the other end rib 12 of the lower plastic 10, and is spaced apart along the width direction of the lower plastic 10. Both the multiple first guide channels 13 and the multiple second guide channels 14 are used to collect electrolyte splashed onto the first surface 111 of the lower plastic 10. Each first limiting protrusion 15 and a second limiting protrusion 16 cooperate to abut against a bare battery cell 310 and limit the bare battery cell 310, while also supporting the bare battery cell 310, so that a gap is formed between the body 11 and the bare battery cell 310.

[0085] In this embodiment, there are two of each of the first guide groove 13 and the second guide groove 14. The two first guide grooves 13 and the two second guide grooves 14 have the same structure, which are all rectangular grooves.

[0086] The first channel 13 includes a first channel bottom wall 131, two first channel side walls 132, and two first channel end walls 133. The first channel bottom wall 131 and the first surface 111 have the same orientation. The two first channel side walls 132 are two surfaces of the first channel 13 that are opposite to each other and spaced apart along the length of the lower plastic 10. The two first channel end walls 133 are two surfaces of the first channel 13 that are opposite to each other and spaced apart along the width of the lower plastic 10. The two first channel end walls 133 are connected to the two first channel side walls 132, and together with the two first channel side walls 132, are connected to the first channel bottom wall 131 and the first surface 111.

[0087] The first guide channel 13 also includes a first slot 13a, which is disposed on the first surface 111 and is opposite to and spaced apart from the bottom wall 131 of the first channel. It can be understood that the two end walls 133 of the first channel and the ends of the two side walls 132 of the first channel away from the bottom wall 131 of the first channel form the first slot 13a.

[0088] The second flow channel 14 includes a second channel bottom wall 141, two second channel side walls 142, and two second channel end walls 143. The second channel bottom wall 141 and the first surface 111 have the same orientation. The two second channel side walls 142 are two surfaces of the second flow channel 14 that are opposite to each other and spaced apart along the length of the lower plastic 10. The two first channel end walls 133 are two surfaces of the second flow channel 14 that are opposite to each other and spaced apart along the width of the lower plastic 10. The two second channel end walls 143 are connected to the two second channel side walls 142, and together with the two second channel side walls 142, are connected to the second channel bottom wall 141 and the first surface 111.

[0089] The second guide channel 14 also includes a second channel opening 14a, which is disposed on the first surface 111 and is opposite to and spaced apart from the bottom wall 141 of the second channel. It can be understood that the two end walls 143 of the second channel and the ends of the two side walls 142 of the second channel away from the bottom wall 141 of the second channel form the second channel opening 14a.

[0090] In this embodiment, there are two first limiting protrusions 15 and two second limiting protrusions 16. The two first limiting protrusions 15 and the two second limiting protrusions 16 have the same structure; both are rectangular protrusions. Each of the two first limiting protrusions 15 is connected to the main body segment 123 of one end rib 12, and the two first limiting protrusions 15 are spaced apart from the two extension segments 124 of the end rib 12 in the width direction of the lower plastic 10. Each of the two second limiting protrusions 16 is connected to the main body segment 123 of the other end rib 12, and the two second limiting protrusions 16 are spaced apart from the two extension segments 124 of the end rib 12 in the width direction of the lower plastic 10. The two first limiting protrusions 15 and the two second limiting protrusions 16 can respectively increase the structural strength of the two end ribs 12.

[0091] The first limiting protrusion 15 includes a first limiting surface 151 and a first limiting side surface 152. The first limiting surface 151 has the same orientation as the second surface 112 of the body 11. The first limiting side surface 152 is connected to the first limiting surface 151, the second surface 112, and the inner side surface 122 of the main body segment 123. In this embodiment, the first limiting surface 151 is approximately rectangular, and the first limiting side surface 152 is approximately U-shaped.

[0092] The second limiting protrusion 16 includes a second limiting surface 161 and a second limiting side surface 162. The second limiting surface 161 has the same orientation as the second surface 112 of the body 11. The second limiting side surface 162 is connected to the second limiting surface 161, the second surface 112, and the inner side surface 122 of the main body segment 123. In this embodiment, the second limiting surface 161 is approximately rectangular, and the second limiting side surface 162 is approximately U-shaped.

[0093] It is understood that in this embodiment, each first limiting protrusion 15 is provided with a first guide groove 13, and each second limiting protrusion 16 is provided with a second guide groove 14. The openings of the multiple first guide grooves 13 and the multiple second guide grooves 14 are all located on the first surface 111 of the body 11, which can save material of plastic 10, which is beneficial to saving manufacturing cost of plastic 10, and can also reduce the weight of plastic 10, which is beneficial to the lightweight design of energy storage device 1000.

[0094] Each first limiting protrusion 15 is provided with a first guide hole 17, and each second limiting protrusion 16 is provided with a second guide hole 18. It can be understood that the lower plastic 10 also includes multiple first guide holes 17 and multiple second guide holes 18. Each first guide hole 17 penetrates the first bottom wall 131 of a first guide groove 13 and the first limiting surface 151 of a first limiting protrusion 15. Each second guide hole 18 penetrates the second bottom wall 141 of a second guide groove 14 and the second limiting surface 161 of a second limiting protrusion 16. The first guide holes 17 are used to allow the electrolyte in the first guide groove 13 to flow back into the battery cell 300, and the second guide holes 18 are used to allow the electrolyte in the second guide groove 14 to flow back into the battery cell 300, realizing the return and reuse of the electrolyte, preventing electrolyte accumulation in the first guide groove 13 and the second guide groove 14, and improving the wettability of the battery cell 300. In this embodiment, there are two of each of the first guide hole 17 and the second guide hole 18.

[0095] In some embodiments, the first guide hole 17 may also be provided on at least one of the two first channel sidewalls 132 or the two first channel endwalls 133 of the first guide channel 13. The second guide hole 18 may also be provided on at least one of the two second channel sidewalls 142 or the two second channel endwalls 143 of the second guide channel 14.

[0096] The lower plastic 10 also includes a plurality of first reinforcing ribs a and a plurality of second reinforcing ribs b. The plurality of first reinforcing ribs a and the plurality of second reinforcing ribs b all protrude from the second surface 112 of the body 11. Each first reinforcing rib a is connected to a main body segment 123 of an end rib 12 and is correspondingly positioned at a heat-melting point on the main body segment 123. Each second reinforcing rib b is connected to an extension segment 124 of an end rib 12 and is correspondingly positioned at a heat-melting point on the extension segment 124.

[0097] In this embodiment, there are two first reinforcing ribs a. One first reinforcing rib a is located between the two first limiting protrusions 15 and is spaced apart from the two first limiting protrusions 15. The other first reinforcing rib a is located between the two second limiting protrusions 16 and is spaced apart from the two second limiting protrusions 16. There are four second reinforcing ribs b. Two of the second reinforcing ribs b are spaced apart from the two first limiting protrusions 15 along the width direction of the lower plastic 10, and the other two second reinforcing ribs b are spaced apart from the two second limiting protrusions 16 along the width direction of the lower plastic 10.

[0098] In this embodiment, the two first reinforcing ribs a and the four second reinforcing ribs b have the same structure, each being approximately a right-angled triangular protrusion. The two right-angled sides of the right-angled triangle of each first reinforcing rib a are respectively connected to the second surface 112 and the inner surface 122 of a main body segment 123 to increase the deformation resistance of the main body segment 123 during the hot-melt process. The two right-angled sides of the right-angled triangle of each second reinforcing rib b are respectively connected to the second surface 112 and the inner surface 122 of an extension segment 124 to increase the deformation resistance of the extension segment 124 during the hot-melt process. This improves the hot-melt stability of the lower plastic 10 and the insulating film 400, further preventing the lower plastic 10 from collapsing after hot-melt with the insulating film 400, preventing the lower plastic 10 from not fitting properly with the end cap 20, improving the structural strength of the lower plastic 10, and also ensuring the structural reliability of the end cap assembly 100.

[0099] Please refer to it again. Figure 4 , Figure 5 and Figure 6 .

[0100] The lower plastic 10 and the end cap 20 are stacked and connected along the thickness direction of the end cap assembly 100. The length direction of the lower plastic 10 is approximately the same as the length direction of the end cap 20, and the width direction of the lower plastic 10 is approximately the same as the width direction of the end cap 20. The second surface 22 of the end cap 20 abuts against the first surface 111 of the body 11. Each through hole 23 of the end cap 20 and one pole post through hole 114 of the lower plastic 10 are coaxial and connected. Each pole post 31 is sequentially inserted through one through hole 23 of the end cap 20 and one pole post through hole 114 of the lower plastic 10, and is insulated and sealed to the end cap 20 by a sealing insulating member 32. Two pressure blocks 33 abut against the second surface 112 of the lower plastic 10, and each pressure block 33 is fitted around the outer periphery of one pole post 31 and welded and fixed to the pole post 31. The pressure relief hole 24 of the end cap 20 and the explosion-proof part 115 of the lower plastic 10 are arranged opposite each other along the thickness direction of the end cap assembly 100. The explosion-proof valve 40 is installed in the pressure relief hole 24 of the end cap 20 and covers the explosion-proof part 115 of the lower plastic 10.

[0101] Please refer to the following: Figure 10 , Figure 11 and Figure 12 , Figure 10 for Figure 4 The diagram shows the structural relationship between the end cap assembly and the battery cell. Figure 11 for Figure 10 The diagram shows the positional relationship between the end cap assembly and the battery cell. (From a bottom perspective) Figure 12 for Figure 2 The diagram shows a partial cross-section of the energy storage device along AA.

[0102] like Figure 10 and Figure 11 As shown, the battery cell 300 is assembled with the end cap assembly 100.

[0103] Specifically, the end cap assembly 100 is mounted on top of two bare battery cells 310. The two bare battery cells 310 are arranged side by side along the width direction of the end cap assembly 100. Each first limiting protrusion 15 and one second limiting protrusion 16 of the lower plastic 10 is located at both ends of the length direction of a bare battery cell 310, and at least a portion of the first limiting surface 151 of the first limiting protrusion 15 and at least a portion of the second limiting surface 161 of the second limiting protrusion 16 abut against the top surface 312 of the bare battery cell 310 to limit the bare battery cell 310. It can be understood that the two first limiting protrusions 15 abut against the two bare battery cells 310 respectively, and the two second limiting protrusions 16 abut against the two bare battery cells 310 respectively, to limit the two bare battery cells 310 and prevent excessive displacement caused by the movement of the two bare battery cells 310. In this embodiment, the width of the battery cell 300 (i.e., the thickness T of the two bare battery cells 310) is smaller than the width of the lower plastic 10. The projection of the battery cell 300 in the thickness direction of the end cap assembly 100 is completely within the projection range of the lower plastic 10.

[0104] In the width direction of the lower plastic 10, two first limiting protrusions 15 are spaced apart from each other, forming a first channel m1 between the battery cell 300 and the body 11. The two first limiting protrusions 15 are spaced apart from the two extensions 124 of the connected end rib 12, forming a second channel m2 between the battery cell 300 and the body 11. Two second limiting protrusions 16 are spaced apart from each other, forming a third channel m3 between the battery cell 300 and the body 11. The two second limiting protrusions 16 are spaced apart from the two extensions 124 of the connected end rib 12, forming a fourth channel m4 between the battery cell 300 and the body 11. The two edges in the width direction of the body 11 and the two sides in the width direction of the battery cell 300 are spaced apart, forming a fifth channel m5. The first channel m1, second channel m2, third channel m3, fourth channel m4, and fifth channel m5 together constitute an exhaust channel m, through which gas generated by the battery cell 300 flows. It can be understood that the venting channel m is formed by the periphery of the battery cell 300, the edge of the body 11, the two first limiting protrusions 15, the two second limiting protrusions 16, and the two end ribs 12.

[0105] Two first limiting protrusions 15 and two second limiting protrusions 16 cooperate to support the battery cell 300, so that the battery cell 300 and the main body 11 are spaced apart and form a manifold space N, which is connected to the exhaust channel m. The explosion-proof part 115 of the lower plastic 10 and the pressure relief hole 24 of the end cap 20 are both located in the manifold space N. Gas entering the manifold space N from the exhaust channel m can flow through the explosion-proof part 115 and the pressure relief hole 24, and break through the explosion-proof valve 40 in the pressure relief hole 24 to be discharged from the energy storage device 1000.

[0106] In this embodiment, the structures of the first limiting protrusion 15 and the second limiting protrusion 16 are substantially the same, and the structures of the two bare battery cells 310 are also substantially the same. The ratio of the width W of each first limiting protrusion 15 (or each second limiting protrusion 16) to the thickness T of a bare battery cell 310 is greater than or equal to 0.3 and less than or equal to 0.9. The width W of the first limiting protrusion 15 (or the second limiting protrusion 16) is the dimension of the first limiting protrusion 15 (or the second limiting protrusion 16) in the X-axis direction. Preferably, the ratio of the width W of each first limiting protrusion 15 (or each second limiting protrusion 16) to the thickness T of a bare battery cell 310 is greater than or equal to 0.4 and less than or equal to 0.7. This avoids the first limiting protrusion 15 and the second limiting protrusion 16 being too small, ensuring that the first limiting protrusion 15 and the second limiting protrusion 16 have sufficient contact area with the bare battery cell 310 to provide good support and limiting effect. It also avoids the first limiting protrusion 15 and the second limiting protrusion 16 being too large, which would affect the size of the exhaust channel m, ensuring that there is a sufficiently large exhaust channel m between the lower plastic 10 and the battery cell 300. For example, the ratio of the width W of each first limiting protrusion 15 (or each second limiting protrusion 16) to the thickness T of a bare battery cell 310 is 0.5.

[0107] In some embodiments, the number of bare cells 310 may not be limited to two, but may also be one, three, four, five, etc. For example, when the number of bare cells 310 is three, the three bare cells 310 are arranged side by side along the width direction of the end cap assembly 100, the number of first limiting protrusions 15 is three, the number of second limiting protrusions 16 is three, and each first limiting protrusion 15 and each second limiting protrusion 16 abuts against the top surface 312 of a bare cell 310 to limit and support the bare cell 310.

[0108] like Figure 3 and Figure 12 As shown, the insulating film 400 covers the periphery and bottom of the battery cell 300 and is heat-fused to multiple hot-melt points on the lower plastic 10. The battery cell 300 with the insulating film 400 assembled and the end cap assembly 100 are installed together into the housing 200, and the end cap 20 of the end cap assembly 100 is welded to the housing 200 at the opening 201.

[0109] In this embodiment, the insulating film 400 and the peripheral surfaces 311 of the two bare battery cells 310 form a confluence channel O, which is connected to the exhaust channel m. When the battery cell 300 generates a large amount of gas during thermal runaway, this gas converges into the confluence channel O between the battery cell 300 and the insulating film 400, and enters the confluence space N through the exhaust channel m between the lower plastic 10 and the battery cell 300. The gas entering the confluence space N passes through the explosion-proof part 115 of the lower plastic 10 and the pressure relief hole 24 of the end cap 20, and breaks through the explosion-proof valve 40 located in the pressure relief hole 24 for rapid exhaust and pressure relief. This prevents the large amount of gas generated by the battery cell 300 during thermal runaway from accumulating inside the energy storage device 1000, reduces the risk of explosion of the energy storage device 1000, and improves the safety of the energy storage device 1000.

[0110] like Figure 11 As shown, along the height direction of the energy storage device 1000, the projected area of ​​the busbar channel O is the difference between the projected area of ​​the lower plastic 10 in the thickness direction of the end cap assembly 100 and the projected area of ​​the two bare cells 310 in the thickness direction of the end cap assembly 100. The projected area of ​​the exhaust channel m is the projected area of ​​the busbar channel O minus the projected areas of the two end ribs 12 in the thickness direction of the end cap assembly 100, the projected areas of the portions of the two first limiting protrusions 15 that do not abut against the cells 300 in the thickness direction of the end cap assembly 100, and the projected areas of the portions of the two second limiting protrusions 16 that abut against the cells 300 in the thickness direction of the end cap assembly 100. In this embodiment, the ratio of the projected area of ​​the exhaust channel m to the projected area of ​​the confluence channel O is greater than or equal to 0.5. This ensures that gas can promptly enter the confluence space N from the confluence channel O via the exhaust channel m, and then exit through the explosion-proof part 115 of the lower plastic 10 and the pressure relief hole 24 of the end cap 20. This prevents the projected area of ​​the exhaust channel m from being too small compared to the projected area of ​​the confluence channel O, which could cause gas to accumulate inside the housing 200 and lead to an explosion, thus improving the safety of the energy storage device 1000. For example, the ratio of the projected area of ​​the exhaust channel m to the projected area of ​​the confluence channel O is 0.85.

[0111] In this embodiment, the first reinforcing rib a and the second reinforcing rib b are correspondingly arranged with the heat-melting points on the end rib 12. When the insulating film 400 and the lower plastic 10 are heat-melted together, the first reinforcing rib a can increase the deformation resistance of the main body section 123 of the end rib 12 during heat melting, and the second reinforcing rib b can increase the deformation resistance of the extension section 124 of the end rib 12 during heat melting, thereby improving the stability of the insulating film 400 and the lower plastic 10 during heat melting. Heat-melting points are provided on the explosion-proof boss 117 to ensure a firm connection between the insulating film 400 and the lower plastic 10, and to prevent the insulating film 400 from blocking the explosion-proof part 115 and affecting the airflow through the explosion-proof part 115.

[0112] In related technologies, existing lower plastic panels have protrusions that abut against the battery cell. These protrusions not only abut against the battery cell but also serve for thermal bonding with the insulating film. These protrusions extend along the width of the lower plastic panel, and their dimensions in this direction are larger than the width of the battery cell. This results in a portion of the protrusion not abutting against the battery cell, rendering it unusable and obstructing venting channels. This limits the design of available channels for gas exhaust within the energy storage device. When the energy storage device experiences thermal runaway, the battery cell rapidly generates a large amount of gas inside the device, which cannot be expelled in time. This gas can easily accumulate inside the energy storage device, leading to problems such as casing explosion, seriously affecting the safety of the energy storage device.

[0113] In this embodiment, multiple first limiting protrusions 15 and multiple second limiting protrusions 16 are respectively provided at both ends of the lower plastic 10 along its length. The multiple first limiting protrusions 15 and multiple second limiting protrusions 16 are symmetrically arranged along the central axis of the lower plastic 10 along its width. The multiple first limiting protrusions 15 are spaced apart along the width of the lower plastic 10, and the multiple second limiting protrusions 16 are spaced apart along the width of the lower plastic 10. Each first limiting protrusion 15 and each second limiting protrusion 16 cooperate to not only abut against the top surface 312 of a bare battery cell 310 and limit the bare battery cell 310 to prevent large displacement caused by the bare battery cell 310 moving around, but also support the bare battery cell 310, so that the bare battery cell 310 and the body 11 are spaced apart. Furthermore, there are gaps between the multiple first limiting protrusions 15 and between the multiple second limiting protrusions 16. When the multiple first limiting protrusions 15 and the multiple second limiting protrusions 16 abut against the battery cell 300, they form partial exhaust channels m between the multiple first limiting protrusions 15 and the multiple second limiting protrusions 16 and the edges of the battery cell 300 and the body 11, respectively. Compared with the exhaust channels formed by the lower plastic and the battery cell in the prior art, this application increases the projected area of ​​the exhaust channel m in the Z-axis direction, thereby preventing the risk of explosion of the energy storage device 1000 caused by the accumulation of gas inside the energy storage device 1000 and improving the safety of the energy storage device 1000.

[0114] In this embodiment, two end ribs 12 are respectively provided at both ends of the lower plastic 10 along its length. Multiple first limiting protrusions 15 are connected to one end rib 12, and multiple second limiting protrusions 16 are connected to the other end rib 12. Both end ribs 12 are provided with heat-melting points, and both end ribs 12 are used for heat-melting connection with the insulating film 400. Compared to the prior art where the lower plastic has two protrusions connected to the insulating film, this saves material and manufacturing costs for the lower plastic 10. A partial exhaust channel m is formed between the edge of the battery cell 300, the edge of the body 11, the two first limiting protrusions 15, and one end rib 12, further increasing the projected area of ​​the exhaust channel m in the Z-axis direction. When the cell 300 experiences thermal runaway and generates a large amount of gas, the exhaust channel m can ensure that the gas inside the energy storage device 1000 flows into the confluence space N in a timely and rapid manner, and is discharged from the explosion-proof valve 40, thus avoiding the accumulation of gas inside the energy storage device 1000 and causing problems such as the explosion of the casing 200, thereby improving the safety of the energy storage device 1000.

[0115] Please see Figure 13 , Figure 13 for Figure 6 A schematic diagram of the structure of the lower plastic of the end cap assembly shown in the second embodiment.

[0116] In this embodiment, unlike the structure of the lower plastic 10 in the first embodiment described above, the main body segment 123 of the end rib 12 is perpendicular to the extension direction of the two extension segments 124, so that the lower plastic 10 has high resistance to deformation at the hot melt point of the two extension segments 124. The second reinforcing rib b can be eliminated from the lower plastic 10, further saving the manufacturing material of the lower plastic 10, reducing the production cost of the lower plastic 10, and helping to achieve the lightweighting of the energy storage device 1000.

[0117] It should be noted that the lower plastic 10 in this embodiment is suitable for situations where the resistance to deformation of the end ribs 12 during hot melting is not critical. Furthermore, content identical to that in the first embodiment described above will not be repeated here.

[0118] Please see Figure 14 and Figure 15 , Figure 14 for Figure 6 The diagram shows a structural schematic of the lower plastic portion of the end cap assembly according to a third embodiment. Figure 15 for Figure 14 The diagram shows the structure of the lower plastic at another angle.

[0119] In this embodiment, the structure of the lower plastic 10 differs from that in the first embodiment described above. In this embodiment, the structures of the plurality of first guide channels 13 and the plurality of second guide channels 14 are different.

[0120] In this embodiment, the first guide channel 13 includes only one first channel sidewall 132, and the first channel sidewall 132 faces the same direction as an end face 101 adjacent to the lower plastic. The first guide channel 13 also includes a third channel opening 13b. The two first channel end walls 133 and the first channel bottom wall 131 on the side away from the first channel sidewall 132 form the third channel opening 13b. The third channel opening 13b is located on an end face 101 of the lower plastic 10, and is opposite to and spaced apart from the first channel sidewall 132. It can be understood that multiple first guide channels 13 penetrate an end face 101 of the lower plastic 10, the first channel sidewall 132 faces the same direction as the end face 101, and the two first channel end walls 133 and the first channel bottom wall 131 are all connected to the end face 101.

[0121] In this embodiment, the second guide channel 14 includes only one second channel sidewall 142, and the second channel sidewall 142 faces the same direction as one end face 101 adjacent to the lower plastic. The second guide channel 14 also includes a fourth channel opening 14b. The two second channel end walls 143 and the second channel bottom wall 141 on the side away from the second channel sidewall 142 form the fourth channel opening 14b. The fourth channel opening 14b is located on the other end face 101 of the lower plastic 10, and is opposite to and spaced apart from the second channel sidewall 142. It can be understood that multiple second guide channels 14 penetrate the other end face 101 of the lower plastic 10, the second channel sidewall 142 faces the same direction as the end face 101, and both the two second channel end walls 143 and the second channel bottom wall 141 are connected to the end face 101.

[0122] In this embodiment, the first guide hole 17 and the second guide hole 18 are omitted from the lower plastic 10. The electrolyte splashed onto the first surface 111 of the lower plastic 10 can flow back directly to the battery cell 300 through multiple first guide channels 13 and multiple second guide channels 14. This not only simplifies the structure and manufacturing process of the lower plastic 10, but also prevents the gas inside the energy storage device 1000 from overflowing the confluence channel O through the first guide hole 17 and the second guide hole 18, instead of entering the confluence space N through the exhaust channel m. This avoids causing chaotic airflow inside the energy storage device 1000 and affecting the exhaust efficiency of the energy storage device 1000.

[0123] Furthermore, during thermal runaway, the battery cell 300 generates not only a large amount of gas but also high temperatures that melt the lower plastic 10. The melted lower plastic 10 is easily carried out of the housing 200 by the gas inside the energy storage device 1000 and is easily ignited, causing a fire. In this embodiment, multiple first guide channels 13 and multiple second guide channels 14 of the lower plastic 10 respectively penetrate both end faces 101 of the lower plastic 10, reducing the material usage of the lower plastic 10 and decreasing the volume of the lower plastic 10 carried out of the housing 200 after melting at high temperatures. This reduces the probability of the melted lower plastic 10 being ignited and causing a fire, ensuring the safety of the energy storage device 1000.

[0124] It should be noted that the contents that are the same as those in the first embodiment described above will not be repeated here. Furthermore, based on the structure of the lower plastic 10 in this embodiment, the second reinforcing rib b can also be omitted. This application does not impose any limitations on this.

[0125] The above are merely some embodiments and implementation methods of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A type of plastic for use in energy storage devices, characterized in that, The lower plastic includes: The body includes a first surface and a second surface, the first surface and the second surface being disposed opposite to each other along the thickness direction of the body; Multiple first limiting protrusions and multiple second limiting protrusions; Multiple first limiting protrusions and multiple second limiting protrusions are provided on the second surface of the body. The multiple first limiting protrusions are located at one end of the lower plastic along its length direction and are spaced apart in the lower plastic along its width direction. The multiple second limiting protrusions are located at the other end of the lower plastic along its length direction and are spaced apart in the lower plastic along its width direction. The multiple first limiting protrusions and multiple second limiting protrusions are symmetrically arranged along the central axis of the lower plastic along its width direction. Each first limiting protrusion and each second limiting protrusion cooperate to support and limit the battery cell of one of the energy storage devices.

2. The lower plastic according to claim 1, characterized in that, The lower plastic also includes two end ribs, both of which protrude from the second surface of the body and are located at both ends of the body in the length direction. Each end rib includes a main body segment and two extension segments. The main body segment is connected to one side edge of the body in the length direction of the lower plastic and extends along the width direction of the lower plastic. The two extension segments are connected to opposite ends of the main body segment in the width direction of the lower plastic and are connected to both sides of the body in the width direction of the lower plastic, and extend along the length direction of the lower plastic to the other end of the lower plastic. The plurality of first limiting protrusions are all connected to the main body segment of one of the end ribs, and the plurality of second limiting protrusions are all connected to the main body segment of another end rib.

3. The lower plastic according to claim 2, characterized in that, Each of the end ribs has a heat-melting point on its main body and two extension sections.

4. The lower plastic according to claim 3, characterized in that, The lower plastic also includes a plurality of first reinforcing ribs, each of which protrudes from the second surface of the body. Each first reinforcing rib is connected to a main body segment of an end rib, and the first reinforcing rib is correspondingly positioned to the hot melt point on the main body segment.

5. The lower plastic according to claim 4, characterized in that, The lower plastic also includes a plurality of second reinforcing ribs, which protrude from the second surface of the body. Each second reinforcing rib is connected to an extension of one of the end ribs, and the second reinforcing ribs are arranged corresponding to the hot melt points on the extensions.

6. The lower plastic according to any one of claims 1-5, characterized in that, The lower plastic also includes a plurality of first guide channels and a plurality of second guide channels. The plurality of first guide channels and the plurality of second guide channels are recessed on the first surface of the body. Each first guide channel protrudes on the second surface of the body to form a first limiting protrusion, and each second guide channel protrudes on the second surface of the body to form a second limiting protrusion.

7. The lower plastic according to claim 6, characterized in that, The lower plastic also includes two end faces, which are arranged opposite to each other along the length of the lower plastic. A plurality of first guide grooves pass through one of the end faces, and a plurality of second guide grooves pass through the other end face.

8. The lower plastic according to claim 6, characterized in that, The lower plastic also includes two end faces, which are arranged opposite to each other along the length of the lower plastic. A plurality of first guide channels and one of the end faces are adjacent to and spaced apart, and a plurality of second guide channels are adjacent to and spaced apart from the other end face. The lower plastic also includes a plurality of first guide holes and a plurality of second guide holes. Each first guide hole is disposed on the bottom wall of the first channel of the first guide groove and communicates with the first guide groove. Each second guide hole is disposed on the bottom wall of the second channel of the second guide groove and communicates with the second guide groove.

9. An end cap assembly, characterized in that, The end cap assembly includes an end cap, a lower plastic, an explosion-proof valve, and the lower plastic as described in any one of claims 1-8. The end cap and the body are stacked and connected along the thickness direction of the end cap assembly. The two end ribs, the plurality of first limiting protrusions, and the plurality of second limiting protrusions are all located on the side of the body facing away from the end cap. The explosion-proof valve is mounted on the end cap.

10. An energy storage device, characterized in that, The energy storage device includes a battery cell, an insulating film, and an end cap assembly as described in claim 9. The end cap assembly is mounted on the top of the battery cell, the insulating film covers the periphery and bottom of the battery cell, and the insulating film is heat-fused to the lower plastic. The insulating film and the periphery of the battery cell form a current-collecting channel. A venting channel is formed between the plurality of first limiting protrusions, the plurality of second limiting protrusions, the two end ribs, the edge of the body, and the periphery of the battery cell. The plurality of first limiting protrusions and the plurality of second limiting protrusions support the battery cell and form a current-collecting space between the body and the battery cell. The venting channel communicates with the current-collecting space and the current-collecting channel. The explosion-proof valve is located within the current-collecting space.

11. The energy storage device according to claim 10, characterized in that, The battery cell includes a plurality of bare battery cells, which are arranged side by side along the width direction of the energy storage device; In the width direction of the energy storage device, the number of the first limiting protrusion and the second limiting protrusion of the lower plastic are equal to the number of the bare battery cells, and each bare battery cell abuts against one of the first limiting protrusions and one of the second limiting protrusions.

12. The energy storage device according to claim 11, characterized in that, The ratio of the dimension of the first limiting protrusion or the second limiting protrusion in the lower plastic width direction to the thickness of the bare battery cell is greater than or equal to 0.3 and less than or equal to 0.

9.

13. The energy storage device according to claim 10, characterized in that, Along the height direction of the energy storage device, the ratio of the projected area of ​​the exhaust channel to the projected area of ​​the confluence channel is greater than or equal to 0.

5.

14. An energy storage system, characterized in that, The energy storage system includes the energy storage device as described in any one of claims 10-13.

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