End cover assembly for battery cell, battery cell, and battery

Abstract

Provided are an end cover assembly (23) for a battery cell (20), the battery cell (20), a battery (10), and an electric device, capable of realizing the connection between an end cover (231) and an insulating member (232) at low costs. The end cover assembly (23) comprises: the end cover (231); the insulating member (232) provided on the side of the end cover (231) facing the interior of the battery cell (20) and used for isolating the end cover (231) from an electrode assembly (21) inside the battery cell (20); and a connecting member (233) provided between the end cover (231) and the insulating member (232) to be connected to the end cover (231) and the insulating member (232).

Description

End cap assembly for battery cell, battery cell, and battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410346890.5, filed on March 25, 2024, entitled “End cover assembly for battery cell, battery cell and battery,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to an end cover assembly for a battery cell, a battery cell, and a battery. Background Art

[0004] To increase the space capacity of battery cells, the end caps are being thinned and made of stronger steel. However, the poor fluidity of steel and the thinness of the end caps make it difficult to form a hot-melt groove for the end caps to connect with the lower plastic, leading to problems with the connection between the end caps and the lower plastic.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide an end cover assembly for a battery cell, a battery cell, and a battery, which can achieve connection between the end cover and the insulating member at a relatively low cost.

[0007] In a first aspect, an end cap assembly for a battery cell is provided, characterized in that it includes: an end cap; an insulating member, arranged on a side of the end cap facing the interior of the battery cell, for spacing the end cap and the electrode assembly inside the battery cell; and a connecting member, arranged between the end cap and the insulating member to connect the end cap and the insulating member.

[0008] In this embodiment of the present application, a connector is provided between the end cap and the insulating member. This connector is used to connect the end cap and the insulating member, thereby achieving a connection between the cover plate and the insulating member when a hot melt slot cannot be used. Furthermore, compared to forming a circle of slots on each end cap and the insulating member, this embodiment of the present application effectively reduces the cost of connecting the end cap and the insulating member.

[0009] In some possible embodiments, the connecting member is a nail-shaped structure, the head of the nail-shaped structure is connected to the first surface of the insulating member, the rod of the nail-shaped structure passes through the insulating member to connect to the end cover, and the first surface of the insulating member is the surface of the insulating member facing the interior of the battery cell.

[0010] The above technical solution sets the connector as a nail-shaped structure, which can effectively reduce the processing difficulty of the connector, thereby achieving the connection between the end cover and the insulating member in a relatively simple manner.

[0011] In some possible embodiments, in a direction away from the interior of the battery cell, an end surface of the rod portion is flush with the end cover, and an outer surface of the rod portion is connected to the end cover.

[0012] In the above technical solution, in the direction away from the interior of the battery cell, the end face of the nail-shaped structure rod is flush with the end cover, and the outer surface of the rod is connected to the end cover, which is simple to implement and has low process difficulty.

[0013] In some possible embodiments, the end cover is provided with a groove facing the interior of the battery cell, and the end surface of the rod portion abuts against the groove.

[0014] In the above technical solution, the end cover is provided with a groove facing the interior of the battery cell, and the end face of the nail-shaped structure rod abuts against the groove, making it easier to achieve the connection between the end cover and the insulating member, and the process difficulty is relatively low.

[0015] In some possible embodiments, the material of the connecting member is the same as that of the end cover.

[0016] In this way, when the connector is connected to the end cover and the insulating member by welding, the connector and the end cover can be better welded, which greatly reduces the process difficulty.

[0017] In some possible embodiments, the material of the connecting member and the material of the end cover are both steel.

[0018] In the above technical solution, the material of the connector and the end cover is set to steel. Since steel is a hard material with high strength, it can effectively improve the strength of the end cover and the connection strength between the end cover and the insulating member.

[0019] In some possible embodiments, the number of the connecting members is between 2 and 4. In this way, the connection strength between the end cover and the insulating member can be effectively improved.

[0020] In some possible embodiments, in the length direction of the end cover, the connection position between the connector and the end cover is located in a quarter area of ​​the end cover, and the connection position between the connector and the insulating member is located in a quarter area of ​​the insulating member; and / or; in the length direction of the end cover, the connection position between the connector and the end cover is located in the central area of ​​the end cover, and the connection position between the connector and the insulating member is set in the central area of ​​the insulating member.

[0021] In the above technical solution, the connection between the connector and the end cap is arranged in the quarter area and / or the center area of ​​the end cap along its length, and the connection between the connector and the insulator can be arranged in the quarter area and / or the center area of ​​the insulator. This ensures sufficient connection strength between the insulator and the end cap. Furthermore, if there are multiple connectors, this arrangement rationally disperses the distribution of the connectors, thereby further improving the connection strength between the insulator and the end cap.

[0022] In some possible embodiments, an insulating layer is provided on the outer surface of the connecting member.

[0023] The above technical solution provides an insulating layer on the outer surface of the connector, which can reduce the probability of short circuit between the end cap and other components through the connector.

[0024] In some possible embodiments, the portion of the connector connected to the insulating member is provided with the insulating layer, thereby reducing the probability of short circuits between the end cap and other components due to electrical conduction through the connector at a relatively low cost.

[0025] In some possible embodiments, the insulation resistance of the insulating layer is greater than 1 Gohm at a voltage of 400 V to 600 V. This ensures that the insulating layer has sufficient insulation performance, thereby further reducing the probability of short circuits between the end cap and other components through electrical conduction via the connector.

[0026] In some possible embodiments, the peel strength of the insulating layer is greater than or equal to 0.1 N / mm.

[0027] The above technical solution sets the peel strength of the insulating layer to be greater than or equal to 0.1N / mm, which can ensure the connection force between the insulating layer and the connector, and reduce the probability of separation between the insulating layer and the connector, thereby affecting the insulation performance of the connector.

[0028] In some possible embodiments, when the insulating layer is connected to a copper foil or an aluminum foil, the insulating layer does not delaminate when immersed in an electrolyte at a temperature of 35° C. to 55° C. for 4 to 6 hours.

[0029] In this way, the life of the insulating layer in the electrolyte environment is ensured to be sufficiently long, thereby effectively increasing the life of the battery cell.

[0030] In some possible embodiments, the insulating layer includes insulating adhesive, the base material of the insulating adhesive includes polyethylene terephthalate, and the backing material of the insulating adhesive includes pressure-sensitive adhesive.

[0031] Since the base material and back adhesive material of the currently commonly used insulating adhesive are polyethylene terephthalate and pressure-sensitive adhesive respectively, this technical solution sets the base material of the insulating adhesive to polyethylene terephthalate and the back adhesive material to pressure-sensitive adhesive, which can be consistent with the currently commonly used insulating adhesive. It can not only maintain the uniformity of the process, but also the process is relatively mature and has a higher success rate.

[0032] In some possible embodiments, the insulating layer is formed by chemical nickel plating.

[0033] Since most current products are insulated by chemical nickel plating, the above technical solution uses chemical nickel plating to form the insulation layer, which not only can be unified with the process of most current products, but also has a relatively mature process and a high success rate.

[0034] In a second aspect, a battery cell is provided, comprising: a shell having an opening; an electrode assembly housed in the shell; and an end cap assembly according to the first aspect and any possible embodiment of the first aspect, the end cap assembly covering the opening to cover the electrode assembly in the shell.

[0035] In a third aspect, a battery is provided, comprising: the battery cell in the second aspect.

[0036] In a fourth aspect, an electrical device is provided, comprising the battery according to the third aspect, wherein the battery is used to provide electrical energy to the electrical device.

[0037] In a fifth aspect, an energy storage device is provided, comprising the battery in the third aspect, wherein the battery is used to store electrical energy for the energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG1 shows a schematic structural diagram of a vehicle according to an embodiment of the present application.

[0039] FIG2 shows a schematic structural diagram of a battery according to an embodiment of the present application.

[0040] FIG3 shows an exploded schematic diagram of a battery cell according to an embodiment of the present application.

[0041] FIG4 shows a schematic diagram of an end cover assembly according to an embodiment of the present application.

[0042] FIG5 shows a schematic exploded view of another end cover assembly according to an embodiment of the present application.

[0043] FIG. 6 shows a top view of the end cap assembly of FIG. 5 .

[0044] FIG. 7 shows a schematic cross-sectional view of the end cover assembly along line AA′ in FIG. 5 .

[0045] FIG8 shows an enlarged view of the end cap assembly at B in FIG7 .

[0046] FIG9 shows a schematic exploded view of yet another end cover assembly according to an embodiment of the present application.

[0047] FIG. 10 shows a top view of the end cap assembly of FIG. 9 .

[0048] FIG11 shows a schematic cross-sectional view of the end cover assembly along line CC′ in FIG9 .

[0049] FIG. 12 shows an enlarged view of the end cap assembly at D in FIG. 11 . DETAILED DESCRIPTION

[0050] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0052] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0053] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0054] The term "multiple" in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0055] In the field of new energy, batteries can serve as the primary power source for electrical devices (such as vehicles, ships, or spacecraft). The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack.

[0056] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0057] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0058] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0059] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0060] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0061] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0062] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0063] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0064] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0065] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0066] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0067] As an example, the negative electrode active material may be a negative electrode active material known in the art for battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.

[0068] In some embodiments, the negative electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. When the metal foam is used as the negative electrode, the surface of the metal foam may or may not be provided with a negative electrode active material.

[0069] As an example, the negative electrode current collector may be filled with or / and deposited with a lithium source material, potassium metal, or sodium metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0070] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0071] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0072] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0073] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0074] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0075] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte can be selected based on needs. The electrolyte can be liquid, gel, or solid.

[0076] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0077] In some embodiments, the electrode assembly is a laminate structure.

[0078] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0079] As an example, multiple positive electrode sheets may be provided, and the negative electrode sheet is folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0080] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0081] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0082] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0083] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0084] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0085] The battery cell may further include an end cap and a lower plastic. Typically, the end cap may be heat-melted to form a plurality of slots, for example, a circle of slots may be formed at the edge of the end cap, through which the lower plastic may be connected to the end cap.

[0086] To increase the space capacity of battery cells, the end caps are being thinned and replaced with stronger steel. However, the poor flowability of steel and the thinness of the end caps make it difficult to form a hot-melt groove for the end caps to connect with the lower plastic, leading to problems with the connection between the end caps and the lower plastic.

[0087] In light of this, embodiments of the present application provide an end cap assembly for a battery cell. This assembly utilizes a connector disposed between the end cap and the insulating member, thereby achieving a connection between the cover plate and the insulating member. Furthermore, compared to forming a ring of slots along the edge of the end cap, embodiments of the present application effectively reduce the cost of connecting the end cap and the insulating member.

[0088] The technical solutions described in the embodiments of this application are applicable to various electrical devices using batteries.

[0089] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0090] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0091] For example, as shown in FIG1 , it is a structural schematic diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A motor 40, a controller 30 and a battery 10 may be provided inside the vehicle 1. The controller 30 is used to control the battery 10 to supply power to the motor 40. For example, a battery 10 may be provided at the bottom, front or rear of the vehicle 1. The battery 10 may be used to power the vehicle 1. For example, the battery 10 may be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery 10 may not only be used as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0092] For example, as shown in FIG2 , it is a schematic structural diagram of a battery 10 according to an embodiment of the present application. The battery 10 may include a plurality of battery cells 20. In addition to the battery cells 20, the battery 10 may also include a case, the interior of which is a hollow structure, and a plurality of battery cells 20 may be accommodated in the case. As shown in FIG2 , the case may include two parts, which are respectively referred to as a first case portion 111 and a second case portion 112, and the first case portion 111 and the second case portion 112 are snapped together. The shapes of the first case portion 111 and the second case portion 112 may be determined according to the shape of the combination of the plurality of battery cells 20, and at least one of the first case portion 111 and the second case portion 112 has an opening. For example, as shown in FIG2 , only one of the first case portion 111 and the second case portion 112 is a hollow cuboid with an opening, and the other is plate-shaped to cover the opening. Here, for example, the second housing portion 112 is a hollow rectangular parallelepiped with only one open face, and the first housing portion 111 is plate-shaped. The first housing portion 111 covers the opening of the second housing portion 112 to form the housing 11 with a closed chamber. This chamber can be used to accommodate multiple battery cells 20. The multiple battery cells 20 are connected in parallel, series, or in a mixed combination and then placed in the housing formed by the first housing portion 111 and the second housing portion 112 being fastened together.

[0093] For another example, unlike that shown in FIG2 , the first and second housing portions 111, 112 can each be a hollow cuboid with only one open face. The opening of the first and second housing portions 111, 112 are positioned opposite each other, and the first and second housing portions 111, 112 are engaged with each other to form a housing having a closed chamber. Multiple battery cells 20 are connected in parallel, series, or in a mixed series arrangement and then placed within the housing formed by the engagement of the first and second housing portions 111, 112.

[0094] In some embodiments, the battery 10 may further include other structures, which will not be described in detail here. For example, the battery 10 may further include a busbar component (not shown in the figure), which is used to realize electrical connection between multiple battery cells 20. Specifically, the busbar component can realize electrical connection between the battery cells 20 by connecting the electrode terminals of the battery cells 20. In some embodiments, the busbar component can be fixed to the electrode terminals of the battery cells 20 by welding. The electrical energy of the multiple battery cells 20 can be further led out through the box through a conductive mechanism. In some embodiments, the conductive mechanism may also belong to the busbar component.

[0095] In order to meet different power requirements, the number of battery cells 20 can be multiple, and multiple battery cells can be connected in series, in parallel, or in hybrid, where hybrid refers to a mixture of series and parallel connections. The battery 10 can also be called a battery pack. In some embodiments, multiple battery cells can first be connected in series, in parallel, or in hybrid to form a battery module, and multiple battery modules can then be connected in series, in parallel, or in hybrid to form the battery 10. In other words, multiple battery cells can directly form the battery 10, or they can first form a battery module, and then the battery module can form the battery 10.

[0096] FIG3 shows a schematic exploded view of a battery cell 20 according to an embodiment of the present application.

[0097] As shown in FIG3 , a battery cell 20 includes one or more electrode assemblies 21, a housing 22, and an end cap assembly 23. The walls of the housing 22 and the end cap assembly 23 are collectively referred to as the walls of the battery cell 20. The housing 22 is shaped according to the combined shape of the one or more electrode assemblies 21. For example, the housing 22 may be a hollow rectangular parallelepiped, a cube, or a cylinder, with one of its faces having an opening to allow the one or more electrode assemblies 21 to be placed within the housing 22. For example, when the housing 22 is a hollow rectangular parallelepiped or a cube, one of its planes is an open face, meaning that the plane has no walls, allowing the interior and exterior of the housing 22 to communicate. When the housing 22 is a hollow cylinder, one of its end faces is an open face, meaning that the end face has no walls, allowing the interior and exterior of the housing 22 to communicate. The end cap assembly 23 covers the opening and is connected to the housing 22 to form a closed cavity for the electrode assemblies 21. The housing 22 is filled with an electrolyte, such as an electrolyte solution.

[0098] The battery cell 20 also includes two electrode terminals 214. The end cap assembly 23 is typically flat, and the two electrode terminals 214 are fixed to the flat surface of the end cap assembly 23. The two electrode terminals 214 are respectively a positive electrode terminal 214a and a negative electrode terminal 214b. Each electrode terminal 214 is provided with a corresponding connecting member 24, also known as a current collecting member, which is located between the end cap assembly 23 and the electrode assembly 21 and is used to electrically connect the electrode assembly 21 and the electrode terminal 214.

[0099] As shown in FIG3 , each electrode assembly 21 has a first electrode tab 221a and a second electrode tab 222a. The first electrode tab 221a and the second electrode tab 222a have opposite polarities. For example, when the first electrode tab 221a is a positive electrode tab, the second electrode tab 222a is a negative electrode tab. The first electrode tab 221a of one or more electrode assemblies 21 is connected to one electrode terminal 214 via a connecting member 24, and the second electrode tab 222a of one or more electrode assemblies 21 is connected to another electrode terminal 214 via another connecting member 24. For example, the first electrode tab 221a is a positive electrode tab and the second electrode tab 222a is a negative electrode tab. The positive electrode terminal 214a is connected to the first electrode tab 221a via a connecting member 24, and the negative electrode terminal 214b is connected to the second electrode tab 222a via another connecting member 24.

[0100] In the battery cell 20 , the electrode assembly 21 can be provided as a single one or multiple ones according to actual use requirements. As shown in FIG3 , four independent electrode assemblies 21 are provided in the battery cell 20 .

[0101] As an example, a pressure relief mechanism 213 may be further provided on one wall of the battery cell 20. The pressure relief mechanism 213 is configured to be activated to release the internal pressure or temperature of the battery cell 20 when the internal pressure or temperature reaches a threshold.

[0102] Optionally, the pressure relief mechanism 213 may be provided on the end cover assembly 23 or on any wall of the housing 22 .

[0103] Figure 4 shows a schematic diagram of an end cap assembly 23 according to an embodiment of the present application. As shown in Figure 4, the end cap assembly 23 may include an end cap 231, an insulating member 232, and a connector 233. The insulating member 232 is disposed on the side of the end cap 231 facing the interior of the battery cell, and serves to separate the end cap 231 from the electrode assembly within the battery cell. The connector 233 is disposed between the end cap 231 and the insulating member 232 to connect the end cap 231 and the insulating member 232.

[0104] Optionally, the connecting member 233 may connect the end cover 231 and the insulating member 232 by means of, but not limited to, welding.

[0105] Optionally, the insulating member 232 may be made of plastic.

[0106] The battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include square-shell, blade-shaped, and polygonal batteries. Polygonal batteries may be, for example, hexagonal batteries.

[0107] When the battery cell is cylindrical, the end cap 231 can be circular. When the battery cell is blade-shaped, the end cap 231 can be polygonal, such as rectangular. In the case of blade-shaped cells, the end cap 231 can be very thin. Blade-shaped cells can increase the energy density of the battery cell within the limited space of the battery.

[0108] In addition to the end cap 231, insulating member 232, and connector 233, the end cap assembly 23 may also include a rivet block, a second insulating member, and a sealing ring. The rivet block is used to secure the electrode terminal protruding from the end cap 231. The second insulating member, also known as the upper plastic, provides insulation between the end cap 231 and the rivet block. The sealing ring is used to form a seal between the electrode terminal and the end cap 231. The sealing ring can be, for example, annular and fits over the electrode terminal.

[0109] In this embodiment of the present application, a connector 233 is provided between the end cap 231 and the insulating member 232. This connector 233 is used to connect the end cap 231 and the insulating member 232, thereby achieving a connection between the cover plate and the insulating member 232 even when a hot melt slot cannot be used. Furthermore, compared to forming a circle of slots on each of the end cap 231 and the insulating member 232, this embodiment of the present application effectively reduces the cost of connecting the end cap 231 and the insulating member 232.

[0110] The end cap 231 may be made of metal, such as aluminum, steel, etc. The steel may be, for example, stainless steel, carbon steel, etc.

[0111] The material of the connecting member 233 can be any material. For example, the material of the connecting member 233 can be steel. In this way, the connection strength between the end cover 231 and the insulating member 232 can be improved.

[0112] When the connector 233 connects the end cap 231 and the insulating member 232 by welding, in order to facilitate welding, in some embodiments, the material of the connector 233 can be the same as that of the end cap 231. Thus, when the connector 233 connects the end cap 231 and the insulating member 232 by welding, the connector 233 and the end cap 231 can be welded more easily, greatly reducing the difficulty of the process.

[0113] For example, the material of the connector 233 and the material of the end cap 231 can both be steel. Since steel is a hard material with high strength, it can effectively improve the strength of the end cap 231 and the connection strength between the end cap 231 and the insulating member 232.

[0114] Referring again to FIG. 4 , the number of the connecting member 233 may be one.

[0115] Alternatively, there may be more than one connector 233. For example, there may be 2 to 4 connectors 233. As shown in Figures 5 to 12, there are 2 connectors 233.

[0116] In this way, the connection strength between the end cover 231 and the insulating member 232 can be effectively improved.

[0117] In the embodiment of the present application, the connection position of the connecting member 233 on the end cover 231 is set corresponding to the connection position on the insulating member 232.

[0118] As an example, the connection position 2331 between the connector 233 and the end cover 231 can be set at any position of the end cover 231 , and correspondingly, the connection position 2332 between the connector 233 and the insulating member 232 can be set at any position of the insulating member 232 .

[0119] As another example, as shown in Figures 4 to 12, in the length direction of the end cover 231, the connection position 2331 between the connector 233 and the end cover 231 can be located in a quarter area of ​​the end cover 231, and the connection position 2332 between the connector 233 and the insulating member 232 can also be located in a quarter area of ​​the insulating member 232.

[0120] For example, if the number of connectors 233 is 2, the connection positions 2332 between the two connectors 233 and the end cover 231 can be symmetrically arranged at one-quarter of the end cover 231 along the length direction of the end cover 231, and at the same time, the connection positions between the two connectors 233 and the insulating member 232 can be symmetrically arranged at one-quarter of the insulating member 232.

[0121] As another example, in the length direction of the end cover 231, the connection position 2331 between the connector 233 and the end cover 231 can be set in the central area of ​​the end cover 231, and the connection position 2332 between the connector 233 and the insulating member 232 can be set in the central area of ​​the insulating member 232.

[0122] In the above technical solution, the connection position 2331 between the connector 233 and the end cap 231 is arranged at one-quarter and / or the center of the end cap 231 along the length direction of the end cap 231. Furthermore, the connection position 2332 between the connector 233 and the insulating member 232 can be arranged at one-quarter and / or the center of the insulating member along the length direction of the insulating member 232. This ensures sufficient connection strength between the insulating member 232 and the end cap 231. Furthermore, if there are multiple connectors 233, the above arrangement rationally disperses the distribution of the connectors 233, thereby further improving the connection strength between the insulating member 232 and the end cap 231.

[0123] In some cases, the insulating member 232 may be a split structure. In this case, the connector 233 may be connected to each insulating member 232. This allows each insulating member 232 to be connected to the end cap 231, thereby improving the overall connection strength between the insulating member 232 and the end cap 231.

[0124] Referring again to Figures 4-12 , in some embodiments, the connector 233 may be a nail-like structure. For example, the connector 233 may be a connecting nail. The head 2333 of the nail-like structure may be connected to the first surface of the insulating member 232, and the stem 2334 of the nail-like structure may pass through the insulating member 232 to connect to the end cap 231. The first surface of the insulating member 232 is the surface of the insulating member 232 facing the interior of the battery cell.

[0125] In other words, the connecting member 233 can pass through the insulating member 232 in the form of a boss snap fit to be connected to the end cover 231 .

[0126] Taking into account that the production processes of different manufacturers may be different, in order to make the end cover assembly 23 of the embodiment of the present application suitable for different scenarios, the embodiment of the present application provides two connection methods between the connector 233 and the end cover 231.

[0127] In one implementation, as shown in Figures 5-8 , the end surface of the nail-shaped rod portion 2334 can be flush with the end cap 231 in a direction away from the interior of the battery cell, and the outer surface of the rod portion 2334 is connected to the end cap 231. Figure 6 is a top view of Figure 5 , Figure 7 is a cross-sectional view of Figure 5 along line A-A', and Figure 8 is an enlarged view of Figure 7 at point B.

[0128] The end face is the face of the connector 233 that is away from the interior of the battery cell.

[0129] In this implementation, a connection position 2331 between the connector 233 and the end cover 231 is located on the surface of the end cover 231 .

[0130] Alternatively, surface welding can be used to obtain the structure shown in Figures 5 to 8. For example, a circle can be welded around the nail-like structure rod 2334 to connect the nail-like structure to the end cap 231. Reference numeral 235 in Figure 8 is a weld mark.

[0131] In the above technical solution, in the direction away from the interior of the battery cell, the end surface of the nail-shaped structure rod 2334 is flush with the end cover 231, and the outer surface of the rod 2334 is connected to the end cover 231, which is simple to implement and has low process difficulty.

[0132] In another implementation, as shown in Figures 9-12, the end cap 231 is provided with a groove facing the interior of the battery cell, and the end surface of the nail-shaped rod portion 2334 abuts against the groove. Figure 10 is a top view of Figure 9, Figure 11 is a cross-sectional view along line C-C' of Figure 9, and Figure 12 is an enlarged view of point D in Figure 11.

[0133] In other words, the rod portion 2334 of the nail-shaped structure can be accommodated in the groove.

[0134] It can be seen from FIG. 12 that, in a direction away from the interior of the battery cell, the size of the rod portion 2334 of the nail-shaped structure is smaller than the size of the end cover 231 .

[0135] In this implementation, a connection position 2331 between the connector 233 and the end cover 231 is located inside the end cover 231 .

[0136] Alternatively, penetration welding can be used to obtain the structures shown in Figures 9 to 12. In Figure 12, 235 is a weld mark.

[0137] In the above technical solution, the end cover 231 is provided with a groove facing the inside of the battery cell, and the end surface of the nail-shaped structure rod 2334 abuts against the groove, making it easier to achieve the connection between the end cover 231 and the insulating member 232, and the process difficulty is relatively low.

[0138] In order to reduce the probability of short circuit caused by electrical conduction between the end cap 231 and other components through the connector 233 , the connector 233 may be insulated.

[0139] As an example, the connecting member 233 itself can be made of insulating material.

[0140] As another example, as shown in FIG. 2 to FIG. 12 , an insulating layer 234 may be provided on the outer surface of the connector 233 .

[0141] The entire outer surface of the connector 233 may be provided with an insulating layer 234 .

[0142] Alternatively, the portion of the connector 233 connected to the insulating member 232 may be provided with an insulating layer 234. In this way, the probability of short circuit between the end cap 231 and other components due to electrical conduction through the connector 233 can be reduced at a lower cost.

[0143] Optionally, the insulating layer 234 may be an insulating glue, an insulating film, etc. Alternatively, the insulating layer 234 may be formed by electroplating.

[0144] In order to ensure that the insulating layer 234 has sufficient insulating properties, thereby further reducing the probability of short circuit caused by electrical conduction between the end cap 231 and other components through the connector 233, in some embodiments, the insulating layer 234 may have an insulation resistance greater than 1 Gohm at a voltage of 400V to 600V.

[0145] For example, at a voltage of 500 V, the insulation resistance of the insulation layer 234 is 2 Gohm. Alternatively, at a voltage of 550 V, the insulation resistance of the insulation layer 234 is 3 Gohm.

[0146] To ensure the connection force between the insulating layer 234 and the connector 233 , in some embodiments, the peel strength of the insulating layer 234 may be greater than or equal to 0.1 N / mm.

[0147] For example, the peel strength of the insulating layer 234 may be 0.2 N / mm, 0.3 N / mm, 0.5 N / mm, 1 N / mm, 2 N / mm, etc.

[0148] In this way, the connection force between the insulating layer 234 and the connector 233 can be ensured, and the probability of separation between the insulating layer 234 and the connector 233, which in turn affects the insulation performance of the connector 233, is reduced.

[0149] In order to ensure that the life of the insulating layer 234 in the electrolyte environment is long enough, thereby improving the life of the battery cell, in some embodiments, when the insulating layer 234 is connected to copper foil or aluminum foil, the insulating layer 234 does not delaminate when immersed in an electrolyte at a temperature of 35°C to 55°C for 4 to 6 hours.

[0150] For example, when the insulating layer 234 is adhered to copper foil or aluminum foil, the insulating layer 234 needs to be immersed in a 40° C. electrolyte for 4.5 hours without delamination. For another example, the insulating layer 234 needs to be immersed in a 45° C. electrolyte for 5 hours without delamination.

[0151] In some embodiments, if the insulating layer 234 includes insulating adhesive, the base material of the insulating adhesive may include but is not limited to polyethylene glycol terephthalate (PET), and the adhesive material of the insulating adhesive may include but is not limited to pressure-sensitive adhesive.

[0152] Since the base material and back adhesive material of the commonly used insulating adhesive are PET and pressure-sensitive adhesive respectively, this technical solution sets the base material of the insulating adhesive to PET and the back adhesive material to pressure-sensitive adhesive, which can be consistent with the commonly used insulating adhesives. It can not only maintain the uniformity of the process, but also the process is relatively mature and has a high success rate.

[0153] As mentioned above, the insulating layer 234 can also be obtained by electroplating. In some embodiments, when the connector 233 is insulated by electroplating, the insulating layer 234 can be formed by nickel electroplating.

[0154] Alternatively, the insulating layer 234 may be formed by chemical nickel plating.

[0155] Since most current products are insulated by chemical nickel plating, the above technical solution uses chemical nickel plating to form the insulation layer, which not only can be unified with the process of most current products, but also has a relatively mature process and a high success rate.

[0156] The present invention also provides a battery cell. The battery cell may include a housing, an electrode assembly, and an end cap assembly. The housing has an opening, the electrode assembly is accommodated in the housing, and the end cap assembly covers the opening to seal the electrode assembly within the housing.

[0157] Optionally, the end cover assembly may be the end cover assembly 23 described above.

[0158] The present application also provides a battery, which may include the battery cells described in the aforementioned embodiments. In some embodiments, the battery may also include a housing, a current collector, and other structures, which are not described in detail here.

[0159] An embodiment of the present application further provides an electrical device, which may include the battery in the aforementioned embodiment, and the battery is used to provide electrical energy to the electrical device.

[0160] In some embodiments, the electrical device may be the vehicle 1 , ship, or spacecraft shown in FIG. 1 .

[0161] An embodiment of the present application further provides an energy storage device, which may include the battery in the aforementioned embodiment, and the battery is used to store electrical energy in the energy storage device.

[0162] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. An end cap assembly for a battery cell, characterized in that: include: end caps; an insulating member, provided on a side of the end cover facing the interior of the battery cell, for spacing the end cover from the electrode assembly inside the battery cell; A connecting member is provided between the end cover and the insulating member to connect the end cover and the insulating member.

2. The end cap assembly according to claim 1, wherein: The connecting member is a nail-shaped structure, the head of the nail-shaped structure is connected to the first surface of the insulating member, the rod of the nail-shaped structure passes through the insulating member to connect to the end cover, and the first surface of the insulating member is the surface of the insulating member facing the interior of the battery cell.

3. The end cap assembly according to claim 2, wherein: In a direction away from the interior of the battery cell, an end surface of the rod portion is flush with the end cover, and an outer surface of the rod portion is connected to the end cover.

4. The end cap assembly according to claim 2, wherein: The end cover is provided with a groove facing the interior of the battery cell, and the end surface of the rod portion abuts against the groove.

5. The end cap assembly according to any one of claims 1 to 4, characterized in that: The material of the connecting piece is the same as that of the end cover.

6. The end cap assembly according to claim 5, wherein: The material of the connecting piece and the material of the end cover are both steel.

7. The end cap assembly according to any one of claims 1 to 6, characterized in that: The number of the connecting members is between 2 and 4.

8. The end cap assembly according to any one of claims 1 to 7, wherein: In the length direction of the end cover, the connection position between the connecting member and the end cover is located in a quarter area of ​​the end cover, and the connection position between the connecting member and the insulating member is located in a quarter area of ​​the insulating member; and / or; In the length direction of the end cover, the connection position between the connecting member and the end cover is located in the central area of ​​the end cover, and the connection position between the connecting member and the insulating member is set in the central area of ​​the insulating member.

9. The end cap assembly according to any one of claims 1 to 8, wherein: An insulating layer is provided on the outer surface of the connecting piece.

10. The end cap assembly according to claim 9, wherein: The insulating layer is provided on a portion of the connecting member connected to the insulating member.

11. The end cap assembly according to claim 9 or 10, characterized in that: At a voltage of 400V to 600V, the insulation resistance of the insulation layer is greater than 1 Gohm.

12. The end cap assembly according to any one of claims 9 to 11, characterized in that: The peel strength of the insulating layer is greater than or equal to 0.1 N / mm.

13. The end cap assembly according to any one of claims 9 to 12, wherein: When the insulating layer is connected to the copper foil or the aluminum foil, the insulating layer does not delaminate when immersed in an electrolyte at a temperature of 35° C. to 55° C. for 4 to 6 hours.

14. The end cap assembly according to any one of claims 9 to 13, characterized in that The insulating layer includes insulating adhesive, the base material of the insulating adhesive includes polyethylene terephthalate, and the backing adhesive material of the insulating adhesive includes pressure-sensitive adhesive.

15. The end cap assembly according to any one of claims 9 to 13, wherein: The insulating layer is formed by chemical nickel plating.

16. A battery cell, characterized in that: include: a housing having an opening; an electrode assembly, housed in the housing; The end cap assembly according to any one of claims 1 to 15, wherein the end cap assembly covers the opening to cover the electrode assembly in the shell.

17. A battery, characterized in that: The battery cell according to claim 16 is included.

Images