A battery cell, a battery, an electric device, and a method for manufacturing a battery cell

Abstract

The application discloses a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell, an electrode assembly arranged in the shell, and an expansion material solidified in a center hole of the electrode assembly. The expansion material can expand to support the center hole. In the battery monomer, the center hole of the electrode assembly is filled with the solidified expansion material. The expansion material can expand after absorbing electrolyte, so that the center hole collapse in the battery cycle process can be effectively avoided, and the safety performance and the cycle life of the battery are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, and more particularly, to a battery monomer, a battery, a power utilization device, and a method for preparing a battery monomer. BACKGROUND

[0002] In recent years, batteries have been widely applied in energy storage power systems such as hydroelectric, thermal, wind and solar power stations, and in many fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc., thereby achieving great development.

[0003] With the rapid development of battery technology, higher requirements are put forward for the cycle life and safety performance of batteries. How to improve the safety performance and cycle life of batteries has become a technical problem to be solved. SUMMARY

[0004] The embodiments of the present application provide a battery monomer, a battery, a power utilization device, and a method for preparing a battery monomer, wherein an expansion material is filled in the center hole of the electrode assembly of the battery monomer, which can expand after solidification to support the center hole, thereby effectively avoiding the collapse of the center hole during the cycle of the battery, improving the safety performance and cycle life of the battery.

[0005] In a first aspect, a battery monomer is provided, comprising: a shell; an electrode assembly, the electrode assembly being arranged in the shell, the electrode assembly having a center hole at the center thereof; and an expansion material, the expansion material being solidified in the center hole, the expansion material being capable of expanding to support the center hole.

[0006] In the embodiments of the present application, the expansion material is arranged in the center hole of the electrode assembly, which can absorb the electrolyte to expand after solidification, thereby supporting the center hole during the cycle of the battery, avoiding the collapse of the center hole due to the expansion effect of the electrode assembly, thereby improving the performance dive of the battery caused by the collapse of the center hole, and improving the cycle life of the battery. At the same time, the lithium precipitation problem caused by the collapse of the center hole structure of the electrode plate in the battery is also improved, and the safety performance of the battery is improved.

[0007] In some embodiments, the expansion material comprises at least one of synthetic resin, including epoxy resin, phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, furan resin, silicone resin, polyester resin, polyamide resin, acrylic resin, polyurethane, vinyl resin, hydrocarbon resin, and polyether resin.

[0008] In some embodiments, the synthetic resin is prepared from an olefin-ester copolymer, the olefin-ester copolymer comprising at least one of ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, and ethylene-methacrylate copolymer.

[0009] In the embodiments of the present application, the synthetic resin prepared from the olefin-ester copolymer is used as the expansion material. In the process of preparing the synthetic resin from the olefin-ester copolymer, the unsaturated carbon-carbon bond is converted into a saturated carbon-carbon bond, and an ester group chain is also introduced. On the one hand, the synthetic resin prepared has a higher expansion rate, and after curing as the expansion material, it absorbs the electrolyte and expands in the battery monomer, having a better supporting effect. On the other hand, the introduced ester group chain enhances the polarity of the synthetic resin, and the degree of infiltration in the electrolyte can be further improved, so that more electrolyte can be absorbed, which helps to improve the infiltration of the electrode assembly in the electrolyte. Thus, by using the synthetic resin prepared from the olefin-ester copolymer as the expansion material, the center hole collapse of the electrode assembly can be effectively avoided, and the infiltration of the electrode assembly in the electrolyte is also improved, which helps to improve the cycle performance and safety performance of the battery.

[0010] In some embodiments, the volume expansion rate of the synthetic resin is 5%-500%, preferably 30%-100%.

[0011] In some embodiments, the expansion material contains solid particles.

[0012] In the embodiments of the present application, the mechanical strength of the solid particles is generally greater than that of the cured expansion material. The addition of solid particles with high mechanical strength in the expansion material helps to improve the mechanical strength of the cured expansion material, so that the supporting performance of the cured expansion material after absorbing the electrolyte is further improved, thereby further improving the center hole collapse problem of the electrode assembly wound to form, and helping to improve the cycle life and safety performance of the battery.

[0013] In some embodiments, the volume percentage of the solid particles in the mixture of the expansion material and the solid particles is 0.1%-50%, preferably 2%-20%; or the mass percentage of the solid particles in the mixture of the expansion material and the solid particles is 0.5%-20%, preferably 1%-10%.

[0014] In some embodiments, the particle size of the solid particles is 1-2000 μm, preferably 5-1000 μm, further preferably 5-500 μm; or further preferably 10-100 μm.

[0015] In some embodiments, the solid particles are hollow solid particles.

[0016] In the embodiments of the present application, the hollow solid particles are used to improve the mechanical strength of the cured expanded material, and help to reduce the weight of the expanded material and the solid particles as a whole, so as to reduce the influence of the expanded material on the energy density of the battery, and ensure the energy density of the battery while improving the cycle life and safety performance of the battery.

[0017] In some embodiments, the solid particles are hollow glass microspheres.

[0018] In some embodiments, the expanded material contains a binder, and the mass percentage of the binder in the mixture of the expanded material and the binder is 0.1%-10%, preferably 1%-5%.

[0019] In the embodiments of the present application, the binder can be added to the expanded material, which helps to improve the chemical stability of the expanded material, and can improve the mechanical properties of the cured expanded material, and help to improve the stability and mechanical strength of the cured expanded material, so as to improve the cycle life and safety performance of the battery.

[0020] In some embodiments, the binder includes at least one of an acrylate compound, a butadiene compound, and a polyurethane compound.

[0021] In some embodiments, the cured expanded material forms a hollow support structure.

[0022] In some embodiments, the cured expanded material forms a porous support structure.

[0023] In some embodiments, the cured expanded material forms a hollow and porous support structure.

[0024] In the embodiments of the present application, the expanded material can form different support structures after curing in the central hole, such as a hollow support structure, a porous support structure, and a hollow and porous support structure. The hollow support structure or the porous support structure can help to reduce the weight of the support structure, reduce the influence of the support structure on the energy density of the battery, and ensure the energy density of the battery while improving the cycle life and safety performance of the battery.

[0025] In a second aspect, a battery is provided, which includes the battery cell of any one of the first aspect.

[0026] In a third aspect, a power consuming device is provided, which includes the battery cell of any one of the first aspect and / or the battery of the second aspect, and the battery cell and / or the battery supply power to the power consuming device.

[0027] In a fourth aspect, a method of manufacturing a battery cell is provided, the method comprising: providing an electrode assembly having a central hole at a center of the electrode assembly; injecting the intumescent material into the central hole; and disposing the electrode assembly into a housing after the intumescent material is solidified in the central hole.

[0028] In some embodiments, the method comprises: drying the electrode assembly and the intumescent material before the intumescent material is solidified in the central hole to solidify the intumescent material in the central hole.

[0029] In some embodiments, the method comprises: disposing a central rod in the central hole before the intumescent material is injected into the central hole; and removing the central rod after the intumescent material is solidified in the central hole.

[0030] In some embodiments, the method comprises: stirring the intumescent material to contain bubbles in the intumescent material before the intumescent material is injected into the central hole.

[0031] In some embodiments, the method comprises: adding solid particles to the intumescent material before the intumescent material is injected into the central hole.

[0032] In some embodiments, the volume percentage of the solid particles in the mixture of the intumescent material and the solid particles is 0.1%-50%, preferably 2%-20%; or the mass percentage of the solid particles in the mixture of the intumescent material and the solid particles is 0.5%-20%, preferably 1%-10%.

[0033] In some embodiments, the particle size of the solid particles is 1 μm-2000 μm, preferably 5 μm-1000 μm, further preferably 5 μm-500 μm; or, further preferably 10 μm-100 μm.

[0034] In some embodiments, the solid particles are hollow solid particles.

[0035] In some embodiments, the solid particles are hollow glass microspheres.

[0036] In some embodiments, the method comprises: adding a binder to the intumescent material before the intumescent material is injected into the central hole.

[0037] In some embodiments, the mass percentage of the binder in the mixture of the intumescent material and the binder is 0.1%-10%, preferably 1%-5%.

[0038] In some embodiments, the intumescent material comprises a synthetic resin, which comprises at least one of an epoxy resin, a phenol resin, a urea resin, a melamine resin, a furan resin, a silicone resin, a polyester resin, a polyamide resin, an acrylic resin, a polyurethane, a vinyl resin, a hydrocarbon resin, a polyether resin.

[0039] In some embodiments, the synthetic resin is prepared from an olefin-ester copolymer, which comprises at least one of an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, an ethylene-methacrylate copolymer.

[0040] In some embodiments, the binder comprises at least one of an acrylate compound, a butadiene compound, a polyurethane compound.

[0041] In some embodiments, the intumescent material has a volume expansion ratio of 5% to 500%, preferably 30% to 100%. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the drawings.

[0043] Figure 1 a schematic structural diagram of a vehicle according to the present application;

[0044] Figure 2 a schematic structural diagram of a battery according to the present application;

[0045] Figure 3 a schematic structural diagram of a battery cell according to the present application;

[0046] Figure 4 a partial cross-sectional schematic diagram of a battery cell according to the present application;

[0047] Figure 5 another partial cross-sectional schematic diagram of a battery cell according to the present application;

[0048] Figure 6 still another partial cross-sectional schematic diagram of a battery cell according to the present application;

[0049] Figure 7 still another partial cross-sectional schematic diagram of a battery cell according to the present application;

[0050] Figure 8 a schematic flowchart of preparing a battery cell according to the present application. DETAILED DESCRIPTION

[0051] The embodiments of the present application will be further described in details with reference to the drawings and examples. The detailed description and drawings of the following examples are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0052] In the description of the present application, it is necessary to point out that, unless otherwise specified, the meaning of "a plurality of" is more than two; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like only for the convenience of describing the present application and simplifying the description, and is not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error.

[0053] The orientation words appearing in the following description are the directions shown in the drawings, and are not limited to the specific structure of the present application. In the description of the present application, it is also necessary to point out that, unless otherwise specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0054] The term "and / or" in the present application is only a description of the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent: there is A, there are A and B, and there is B. In addition, the character " / " in the present application generally represents that the front and rear associated objects are in an "or" relationship.

[0055] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as understood by a person skilled in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application; the terms "include" and "have" in the specification and claims of the present application and their any variants are intended to cover the non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application are used to distinguish different objects, and are not used to describe a specific order or primary and secondary relationship.

[0056] Reference to an "embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described in this application can be combined with other embodiments in accordance with the application.

[0057] In this application, a battery refers to a physical module including one or more battery cells to provide electrical energy. For example, the battery mentioned in this application can include a battery module or a battery pack, etc. The battery generally includes a box for packaging one or more battery cells. The box can avoid the influence of liquid or other foreign matters on the charging or discharging of the battery cells.

[0058] Optionally, the battery cell can include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc. The embodiments of this application are not limited thereto. In some embodiments, the battery cell can also be referred to as an electrode.

[0059] The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode tab, a negative electrode tab, and a separator. The battery cell mainly works by moving metal ions between the positive electrode tab and the negative electrode tab. The positive electrode tab includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on at least one surface of the positive electrode current collector. The current collector without the positive electrode active material layer protrudes from the current collector with the positive electrode active material layer, and the current collector without the positive electrode active material layer serves as a positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode tab includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on at least one surface of the negative electrode current collector. The current collector without the negative electrode active material layer protrudes from the current collector with the negative electrode active material layer, and the current collector without the negative electrode active material layer serves as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon-carbon composite material, etc. In order to ensure that no fuse occurs when passing a large current, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The separator can be in the form of a separator, and the material of the separator can be polypropylene (PP) or polyethylene (PE), etc.

[0060] In addition, the electrode assembly includes a jelly-roll type electrode assembly and a stack type electrode assembly in terms of structure. The jelly-roll type electrode assembly is manufactured by winding a continuous long sheet type positive electrode and a negative electrode with a separator interposed therebetween, and then winding the same around a center pin. The stack type electrode assembly is manufactured by alternately stacking a positive electrode and a negative electrode with a separator interposed therebetween in a Z shape.

[0061] The development of battery technology should take into account various design factors, such as energy density, cycle life, discharge capacity, charge / discharge rate, and other performance parameters, to improve the safety of the battery in the electrical device.

[0062] In some battery packaging technologies, a plurality of battery cells are first integrated into a battery module, and then the battery module is installed in a battery case to form a battery pack. In other battery packaging technologies, a plurality of battery cells can be directly installed in a case to form a battery pack, eliminating the intermediate state of the battery module, thereby reducing the mass of the battery pack and improving the energy density of the battery. The second packaging technology can also be referred to as a cell-to-pack packaging technology in the related art, and the battery pack can be referred to as a battery in this application.

[0063] Conventional battery cells include cylindrical battery cells and square battery cells (e.g., blade battery cells). The cylindrical battery cell generally has a cylindrical housing and an electrode assembly wound in a cylindrical or elliptical cylindrical shape. According to the power requirement, one or more cylindrical or elliptical cylindrical electrode assemblies can be accommodated in the cylindrical housing, and multiple electrode assemblies are stacked in the cylindrical housing. The square battery cell can have a square housing and an electrode assembly wound in a cylindrical or elliptical shape. According to the power requirement, one or more cylindrical or elliptical cylindrical electrode assemblies can be accommodated in the square housing, and multiple electrode assemblies are stacked in the square housing. Alternatively, the square battery cell can have a square housing and a stack type electrode assembly, and the number of stacks in the square housing can be flexibly set according to the power requirement.

[0064] In the process of processing the battery cell using the wound electrode assembly, since the electrode assembly is wound around the center pin, a center hole is left at the center of the columnar electrode assembly when the center pin is pulled out to complete the winding. In the cycle process of the battery, the pole piece in the electrode assembly will swell to different degrees due to the change of the active material structure, the occurrence of the electrode side reaction and other factors. Due to the self-binding effect of the columnar structure of the wound electrode assembly, the outward swelling of the pole piece is bound, and instead, the pole piece swells into the center hole, causing the pole piece to collapse into the center hole, destroying the structure of the pole piece. As a result, the polarization reaction at the center hole is intensified, and the lithium precipitation phenomenon occurs. The occurrence of the lithium precipitation phenomenon will further intensify the swelling effect of the pole piece and the further collapse of the center hole, forming a vicious cycle, causing the cycle capacity of the battery to decrease sharply and the cycle life to decay rapidly, that is, the cycle diving is triggered. Severe lithium precipitation phenomenon will further cause lithium dendrites to pierce the separator, causing serious safety problems.

[0065] Therefore, the present application provides a battery cell, a battery and an electric device. In the battery cell, the center hole of the electrode assembly is filled with an expansion material, which can absorb the electrolyte expansion after solidification to support the center hole, thereby effectively improving the center hole collapse problem of the columnar electrode assembly in the cycle process of the battery, and improving the cycle performance and safety performance of the battery.

[0066] It should be understood that the above "lithium precipitation" and "lithium precipitation phenomenon" refer to the process of lithium ions precipitating into lithium metal on the surface of the negative pole piece.

[0067] The technical solutions described in the embodiments of the present application are applicable to various electric devices using batteries.

[0068] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not specially limit the above electric devices.

[0069] The following embodiments take the vehicle as an example for convenience of description.

[0070] For example, as shown in FIG. 1, the vehicle includes a battery pack 1, a motor 2, a controller 3, a power management system 4, a power distribution system 5, a power supply system 6, a power conversion system 7, a power storage system 8, a power utilization system 9 and a power supply system 10, etc. Figure 1The diagram shows a structural schematic of a vehicle 1 according to this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 11, a controller 12, and a battery 10 can be installed inside vehicle 1. The controller 12 controls the battery 10 to supply power to the motor 11. For example, the battery 10 can be installed at the bottom, front, or rear of vehicle 1. The battery 10 can be used to power vehicle 1. For example, the battery 10 can serve as the operating power source for vehicle 1, for example, for the electrical system of vehicle 1, such as for the power requirements of vehicle 1's starting, navigation, and operation. In another embodiment of this application, the battery 10 can not only serve as the operating power source for vehicle 1, but also as the driving power source for vehicle 1, replacing or partially replacing gasoline or natural gas to provide driving power for vehicle 1.

[0071] To meet different power demands, battery 10 may include multiple battery cells, such as multiple cylindrical battery cells. These battery cells can be connected in series, parallel, or a combination thereof; a combination of series and parallel connections refers to a mix of both. Battery 10 may also be referred to as a battery pack. In some embodiments, multiple battery cells can first be connected in series, parallel, or a combination thereof to form a battery module, and then multiple battery modules can be connected in series, parallel, or a combination thereof to form battery 10. That is, multiple battery cells can directly form battery 10, or they can first be formed into battery modules, and then the battery modules can be assembled into battery 10.

[0072] For example, such as Figure 2 The diagram shown is a structural schematic of a battery 10 according to this application. The battery 10 may include multiple battery cells 20. In addition to the battery cells 20, the battery 10 may also include a housing (or cover), the interior of which is a hollow structure, and the multiple battery cells 20 can be accommodated within the housing. Figure 2 As shown, the housing may include two parts, referred to here as the first part 111 and the second part 112, which are fastened together. The shapes of the first part 111 and the second part 112 can be determined according to the combined shape of multiple battery cells 20. Both the first part 111 and the second part 112 may have an opening. For example, both the first part 111 and the second part 112 may be hollow cuboids with only one open face. The openings of the first part 111 and the second part 112 are opposite to each other, and the first part 111 and the second part 112 are fastened together to form a housing with a closed cavity. Multiple battery cells 20 are connected in parallel, series, or mixed configurations and placed inside the housing formed by the fastening of the first part 111 and the second part 112.

[0073] In some embodiments, the battery 10 can further include other structures, which are not described herein again. For example, the battery 10 can further include a busbar component (not shown in the figure) for realizing electrical connection between the plurality of battery cells 20, such as parallel connection or series connection or mixed connection. 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 plurality of battery cells 20 can be further led out through the box by a conductive mechanism. In some embodiments, the conductive mechanism can also belong to the busbar component.

[0074] According to different power requirements, the number of battery cells 20 can be set to any value. The plurality of battery cells 20 can be connected in series, in parallel or in mixed connection to achieve larger capacity or power.

[0075] For the convenience of description, the following mainly takes the cylindrical battery cell 20 shown in Figure 2 as an example for description. It should be understood that the battery cell of the embodiments of the present application can be a cylindrical battery cell, a square shell battery cell or a blade battery cell.

[0076] Figure 3 is a structure diagram of a battery cell 20 according to an embodiment of the present application. As shown in Figure 3 , the battery cell 20 can include a shell 210, an electrode assembly 220 and an end cap assembly 230. The shell 210 and the end cap assembly 230 form an outer shell or a battery box, and the wall of the shell 210 and the wall of the end cap assembly 230 are both referred to as the wall of the battery cell 20. The shell 210 is determined according to the shape of the combined one or more electrode assemblies 220. For example, the shell 210 can be a hollow cylinder as shown in Figure 3 , or if the battery cell 20 is a blade battery cell, the shell 210 can be a long cuboid with a long length. And at least one face of the shell 210 has an opening so that the one or more electrode assemblies 220 can be placed in the shell 210. For example, when the shell 210 is a hollow cylinder, the end face of the shell 210 is an open face, i.e. the end face does not have a wall so that the inside and outside of the shell 210 are communicated. As can be seen from Figure 3 , the cylindrical battery cell has two circular end faces, and the column part between the two circular end faces can include the electrode assembly 220. The end cap assembly 230 covers the opening and is connected with the shell 210 to form a closed cavity for preventing the electrode assembly 220. The shell 210 is filled with an electrolyte, such as an electrolyte solution.

[0077] The end cap assembly 230 includes an end cap 231 and an electrode terminal 240, which can be disposed on the end cap 231. The end cap assembly 230 further includes a connecting member, or also referred to as a current collecting member, for electrically connecting the electrode assembly 220 and the electrode terminal 240.

[0078] Each electrode assembly 220 can have two tabs, for example, a first tab and a second tab, which have opposite polarities. For example, when the first tab is a positive tab, the second tab is a negative tab. The first tabs of one or more electrode assemblies 220 are connected to one electrode terminal via one connecting member, and the second tabs of the one or more electrode assemblies 220 are connected to another electrode terminal via another connecting member.

[0079] In the battery cell 20, the electrode assembly 220 can be provided as a single one or multiple ones according to actual use requirements. Figure 3 As shown, the battery cell 20 is provided with one electrode assembly 220.

[0080] The battery cell 20 can further be provided with a pressure relief mechanism (not shown in the figure). The pressure relief mechanism is used to actuate to release the internal pressure or temperature when the internal pressure or temperature of the battery cell 20 reaches a threshold value.

[0081] The pressure relief mechanism can be various possible pressure relief structures, which are not limited by the embodiments of the present application. For example, the pressure relief mechanism can be a temperature-sensitive pressure relief mechanism configured to be able to melt when the internal temperature of the battery cell 20 provided with the pressure relief mechanism reaches a threshold value; and / or, the pressure relief mechanism can be a pressure-sensitive pressure relief mechanism configured to be able to break when the internal air pressure of the battery cell 20 provided with the pressure relief mechanism reaches a threshold value.

[0082] Figure 4 A partial cross-sectional view of the battery cell 20 in the axial direction is shown in the embodiments of the present application. As shown in Figure 3 and Figure 4 The battery cell 20 includes a housing 210, an electrode assembly 220, and an expansion material 250. The electrode assembly 220 is disposed in the housing 210 and has a central hole 221 at the center; and the expansion material 250 is solidified in the central hole 221, and the solidified expansion material 250 can expand to support the central hole 221.

[0083] Specifically, in the production process of the battery cell 20, first, the electrode assembly 220 is arranged in the shell 210, then electrolyte is injected into the shell, and finally the shell 210 is encapsulated by the end cover assembly 230 to obtain the battery cell 20. In the production process of the battery cell 20 in the embodiment, the expansion material 250 is filled into the center hole 221 of the electrode assembly 220, so that the expansion material 250 fills the center hole 221. The expansion material 250 solidifies to form a support structure during the drying process of the electrode assembly 220. In other words, the support structure is formed by the solidification of the expansion material 250 arranged in the center hole 221. The support structure absorbs the electrolyte and expands after the electrolyte is injected into the shell. Therefore, the solidified expansion material 250 can fill and support the center hole 221.

[0084] In the embodiment, by introducing the support structure formed by the solidification of the expansion material in the center hole 221, the cycle diving or safety problem caused by the collapse of the center hole 221 of the electrode assembly 220 in the cycle process of the battery 10 can be avoided. In addition, compared with the use of the expansion tape, on the one hand, the support structure formed by the solidification of the expansion material 250 can expand as a whole and has a high expansion rate and good support effect, while the expansion tape is usually composed of a substrate, an adhesive and an expansion glue. In the case that the volume of the center hole 221 is limited, only the expansion glue in the expansion tape can expand, and the support effect is limited. On the other hand, the expansion material 250 can be directly injected into the center hole 221, and the support structure can be formed after solidification without introducing other structures. However, the expansion tape needs to be arranged in the center hole 221 by surrounding a fixed structure, for example, the expansion tape is adhered to a needle-shaped object and then arranged in the center hole 221. The existence of the fixed structure increases the weight of the battery cell 20 but does not contribute to the capacity, reduces the energy density of the battery 10, and easily scratches the electrode assembly around the center hole 221 during the process of putting the expansion tape into the center hole 221, which increases the assembly difficulty and reduces the product yield.

[0085] Optionally, the expansion material 250 includes a synthetic resin. The synthetic resin includes at least one of an epoxy resin, a phenolic resin, a urea-formaldehyde resin, a melamine-formaldehyde resin, a furan resin, a silicone resin, a polyester resin, a polyamide resin, an acrylic resin, a polyurethane, a vinyl resin, a hydrocarbon resin, and a polyether resin.

[0086] In the embodiment, the synthetic resin can be selected as the expansion material 250. The solidified synthetic resin has a large expansion rate after absorbing liquid, which can effectively support the center hole 221 of the electrode assembly 220, thereby avoiding the collapse of the center hole 221 in the cycle process of the battery 10 and helping to improve the cycle life and safety performance of the battery 10.

[0087] Optionally, the expanding material 250 includes liquidswelling rubber (LSR), which includes at least one of nitrile rubber, hydrogenated nitrile rubber, and chloroprene rubber. Optionally, the expanding material 250 can also be other materials capable of absorbing liquid and expanding after curing, which will not be elaborated here.

[0088] Optionally, the synthetic resin is prepared from an olefin-ester copolymer, which includes at least one of ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, and ethylene-methacrylate copolymer. Preferably, the olefin-ester copolymer is selected from ethylene-ethyl acrylate copolymer.

[0089] In the process of preparing synthetic resins from olefin-ester copolymers, the unsaturated carbon-carbon bonds in the copolymer are converted into saturated carbon-carbon bonds, and ester chains are introduced into the polymer, thereby enhancing the polarity of the synthetic resin. This stronger polarity improves the wettability of the electrolyte in the synthetic resin, making it more conducive to liquid absorption and swelling, thus forming a more stable supporting structure.

[0090] In this embodiment, a synthetic resin prepared by using ethylene-ethyl acrylate copolymer is used as the expansion material 250. On the one hand, the expansion material 250 has better supporting performance after curing, which improves the collapse problem of the central hole 221 during battery cycling and effectively improves the cycle performance and safety performance of battery 10. On the other hand, due to the enhanced wettability of electrolyte in the expansion material 250, it can absorb more electrolyte after curing, which is more conducive to electrolyte wetting of the electrode assembly 220 around the central hole 221, thereby reducing the polarization reaction in this area, reducing the probability of lithium plating, and further improving the safety performance of battery 10.

[0091] Optionally, the volume expansion rate of the expanding material 250 is 5%-500%, preferably 30%-100%.

[0092] Figure 5 This is a partial cross-sectional view of another axial direction of a battery cell 20 according to an embodiment of this application.

[0093] like Figure 5 As shown, optionally, the expanded material 250 contains solid particles 251.

[0094] Specifically, the solid particles 251 are any substance with a certain particle size, a mechanical strength greater than the cured expanded material 250, and electrochemical stability. The mechanical strength includes at least one of compressive strength, bending strength, and tensile strength. Having electrochemical stability means that the solid particles 251 do not participate in the electrochemical reactions inside the battery cell 20 during the cycling of the battery 10, and are electrochemically inert. The solid particles 251 are contained in the expanded material 250, i.e., the solid particles 251 are added to the expanded material 250, and the uniformly mixed expanded material 250 and solid particles 251 are jointly injected into the central hole 221. After the expanded material 250 is cured, a support structure containing the solid particles 251 is formed, which can absorb the electrolyte expansion and thus support the central hole 221.

[0095] For example, the solid particles 251 are a substance with a tensile strength greater than or equal to 350 kg / cm 2 ; or, the solid particles 251 are a substance with a bending strength greater than or equal to 400 kg / cm 2 ; or, the solid particles 251 are a substance with a compressive strength greater than or equal to 300 kg / cm 2 .

[0096] It should be understood that the shape of the solid particles 251 can be spherical, triangular pyramidal, cubic, or other irregular solid shapes. Preferably, the solid particles 251 are spherical, which have stronger structural stability and are easier to disperse uniformly in the expanded material 250 with fluidity.

[0097] In this embodiment, by introducing solid particles 251 with higher mechanical strength into the expanded material 250, the mechanical strength and support performance of the cured expanded material 250 can be effectively improved, further preventing the collapse of the central hole 221 during the cycling of the battery 10, thereby improving the cycling performance and safety performance of the battery 10.

[0098] Alternatively, the volume percentage of the solid particles 251 in the mixture of the expanded material 250 and the solid particles 251 is 0.1%-50%, preferably 2%-20%; or the mass percentage of the solid particles 251 in the mixture of the expanded material 250 and the solid particles is 0.5%-20%, preferably 1%-10%.

[0099] Specifically, the adding proportion of the solid particles 251 in the expanded material 250 can be adjusted according to the actual needs of the different batteries 10, battery monomers 20. For example, in the mixture of the expanded material 250 and the solid particles 251, the mass of the expanded material 250 before solidification is m1, and the mass of the solid particles 251 is m2, then m1 and m2 satisfy: 0.5%≤m2 / (m1+m2)≤20%. In some embodiments, 2%≤m2 / (m1+m2)≤20%. For another example, in the mixture of the expanded material 250 and the solid particles 251, the volume of the expanded material 250 before solidification is v1, and the total volume of the solid particles 251 is v2, then v1 and v2 satisfy: 0.1%≤v2 / (v1+v2)≤50%. In some embodiments, 2%≤v2 / (v1+v2)≤20%.

[0100] Optionally, the solid particles 251 are hollow solid particles 251.

[0101] Specifically, the solid particles 251 can have a hollow structure, and the solid particles 251 with the hollow structure have a lighter mass compared to the solid particles 251 with a solid structure. When m2 / (m1+m2) is constant, more solid particles 51 can be added in the expanded material 250, further improving the mechanical properties of the expanded material 250 after solidification; or when v2 / (v1+v2) is constant, it helps to reduce the total weight of the expanded material 250 and the solid particles 251, i.e. to reduce the weight of the support structure with the solid particles 251, thereby reducing the adverse effect of the support structure with the solid particles 251 on the energy density of the battery 10, and ensuring the energy density of the battery 10.

[0102] Optionally, the particle size of the solid particles 251 is 1 μm-2000 μm, preferably 5 μm-1000 μm, further preferably 5 μm-500 μm; or further preferably 10 μm-100 μm.

[0103] Specifically, the particle size of the solid particles 251 can be selected according to actual needs. For example, in the case of requiring higher mechanical strength, solid particles 251 with smaller particle size are selected; in the case of requiring to control the bulk density, solid particles 251 with larger particle size are selected.

[0104] Optionally, the solid particles 251 are hollow glass microspheres.

[0105] Specifically, the hollow glass microspheres have good mechanical strength, and the compressive strength can reach 700 kg / cm 2 , and the pressure resistance can reach 2111.19 kg / cm 2The hollow glass microspheres can effectively improve the supporting performance of the cured intumescent material 250, and have a light mass, which can reduce the influence of the introduction of the intumescent material 250 in the battery monomer 20 on the energy density of the battery 10. Thus, by using the hollow glass microspheres as the solid particles 251 added to the intumescent material 250, the mechanical strength of the cured intumescent material 250 can be improved while the mass of the intumescent material 250 is reduced, which helps to improve the safety performance and cycle performance of the battery while ensuring the energy density of the battery.

[0106] Optionally, the intumescent material 250 contains a binder, and the mass percentage of the mixture of the intumescent material 250 and the binder is 0.1%-10%, preferably 1%-5%.

[0107] Specifically, a binder can also be added to the intumescent material 250. The addition of the binder helps to improve the chemical stability of the intumescent material 250 and improve the mechanical properties of the cured intumescent material 250. In the mixture of the intumescent material 250 and the binder, or in the mixture of the intumescent material 250, the binder and the solid particles 251, the mass of the intumescent material 250 before curing is m1, and the mass of the binder is m3, then m1 and m3 satisfy: 0.1%≤m3 / (m1+m3)≤10%. In some embodiments, 1%≤m3 / (m1+m3)≤5%.

[0108] In this embodiment, by adding a binder to the intumescent material 250, the stability and mechanical strength of the cured intumescent material 250 can be effectively improved, which helps to improve the cycle performance and safety performance of the battery 10.

[0109] Optionally, the binder includes at least one of an acrylate compound, a butadiene compound, and a polyurethane compound. Preferably, the binder is an acrylate compound.

[0110] In addition to adding the above-mentioned substances to the intumescent material 250 to further optimize the function of the intumescent material 250, the cured intumescent material 250 can also have the following structural improvements.

[0111] Figure 6 is a further axial partial cross-sectional view of a battery monomer 20 according to an embodiment of the present application.

[0112] Optionally, as shown in Figure 6 the cured intumescent material 250 forms a hollow support structure.

[0113] Specifically, before injecting the expansion material 250 into the center hole 221, a center rod with a radius smaller than that of the center hole 221 can be arranged in the center hole 221, and after injecting the expansion material 250, the expansion material 250 will fill the volume in the center hole 221 except for the center rod, and after the expansion material 250 solidifies, the center rod is removed, thereby leaving a hollow structure corresponding to the shape of the center rod in the solidified expansion material 250, i.e., forming a hollow support structure as shown in FIG. 2B. Figure 6

[0114] In this embodiment, the solidified expansion material 250 can be controlled to be a hollow support structure, which has a lighter mass while having a good supporting effect on the center hole 221, can further reduce the influence of the support structure on the energy density of the battery 10, and in addition, the hollow support structure can further accommodate more electrolyte at the center hole 221, which is more conducive to the wetting of the electrode assembly 220 at the center hole 221, and helps to improve the cycle stability and safety performance of the battery 10.

[0115] Figure 7 FIG. 2D is another axial partial cross-sectional view of a battery cell 20 according to an embodiment of the present application.

[0116] Alternatively, as shown in FIG. 2E, the solidified expansion material 250 forms a porous support structure. Figure 7

[0117] Specifically, when injecting the expansion material 250 into the center hole 221, the expansion material 250 filled in the center hole 221 can contain an appropriate amount of bubbles by using an injection nozzle with a special structure, or an appropriate amount of bubbles can be introduced into the slurry form of the expansion material 250 by rapidly stirring the expansion material 250, and the expansion material 250 containing bubbles is directly injected into the center hole 221, so that the solidified expansion material 250 has a pore structure corresponding to the shape of the bubbles, i.e., forming a porous support structure as shown in FIG. 2E. Figure 7

[0118] In this embodiment, the solidified expansion material 250 can be controlled to be a porous support structure, which, similar to the hollow support structure, can reduce the influence of the support structure on the energy density of the battery 10, accommodate more electrolyte, promote the wetting of the electrode assembly 220 at the center hole 221, and improve the cycle performance and safety performance of the battery 10.

[0119] In addition, the present application also provides a battery 10, which can include the battery cell 20 in the foregoing embodiments. In some embodiments, the battery 10 can also include a box, a busbar component, and other structures, which will not be described one by one here.

[0120] ​​​The embodiments of the present application also provide a power consuming device, which can include the battery cell and / or the battery in the foregoing embodiments, and the battery cell and / or the battery are used to supply power for the power consuming device. In some embodiments, the power consuming device can be Figure 1 a vehicle 1, a ship or a spacecraft in the embodiments of the present application.

[0121] The embodiments of the present application also provide a method for manufacturing the battery cell 20, Figure 8 a schematic flowchart of the method 800 for manufacturing the battery cell 20.

[0122] As shown in Figure 8 the method 800 includes the following steps.

[0123] S801, providing an electrode assembly 220 having a center hole 221 at the center of the electrode assembly 220;

[0124] S802, injecting an expansion material 250 into the center hole 221;

[0125] S803, after the expansion material 250 is solidified in the center hole 221, arranging the electrode assembly 220 in a shell 210.

[0126] In the embodiments, the expansion material 250 generally has a certain fluidity before solidification. By injecting the expansion material 250 into the center hole 221 of the electrode assembly 220, the expansion material 250 is solidified in the center hole 221 to form a support structure corresponding to the shape of the center hole 221. In the process of manufacturing the battery cell 20, after the solidified expansion material 250 and the electrode assembly 220 are arranged in the shell 210, an electrolyte is injected into the shell. The solidified expansion material 250 can absorb the electrolyte to expand and support the center hole 221, so as to avoid the collapse of the center hole 221 in the cycle process of the battery 10, and help to improve the cycle performance and safety performance of the battery 10.

[0127] Optionally, the method 800 includes: before the expansion material 250 is solidified in the center hole 221, drying the electrode assembly 220 and the expansion material 250, so that the expansion material 250 is solidified in the center hole 221.

[0128] Optionally, the method 800 includes: before the expansion material 250 is injected into the center hole 221, arranging a center rod in the center hole 221; and after the expansion material 250 is solidified in the center hole 221, removing the center rod.

[0129] In the embodiments, by arranging the center rod before injecting the expansion material 250, the expansion material 250 fills the remaining part of the center hole 221 except the center rod. After the expansion material 250 is solidified, the center rod is removed, leaving a hollow structure corresponding to the shape of the center rod. Thus, a hollow support structure can be obtained.

[0130] Optionally, the method 800 comprises: before injecting the expansion material 250 into the central hole 221, stirring the expansion material 250 so that the expansion material 250 contains bubbles.

[0131] In this embodiment, by stirring the expansion material 250 before injecting the expansion material 250 into the central hole 221, bubbles can be introduced into the expansion material 250, and the expansion material 250 containing bubbles is injected into the central hole 221, and a porous structure corresponding to the shape of the bubbles will be formed in the solidified expansion material 250, thereby obtaining a porous support structure.

[0132] Optionally, the method 800 comprises: before injecting the expansion material 250 into the central hole 221, adding solid particles 251 to the expansion material 250.

[0133] Optionally, the volume percentage of the solid particles 251 in the mixture of the solid particles 251 and the expansion material 250 is 0.1%-50%, preferably 2%-20%; or the mass percentage of the solid particles 251 in the mixture of the solid particles 251 and the expansion material 250 is 0.5%-20%, preferably 1%-10%.

[0134] Optionally, the particle size of the solid particles 251 is 1 μm-2000 μm, preferably 5 μm-1000 μm, further preferably 5 μm-500 μm; or further preferably 10 μm-100 μm.

[0135] Optionally, the solid particles are hollow solid particles.

[0136] Optionally, the solid particles are hollow glass microspheres.

[0137] Optionally, the method 800 comprises: before injecting the expansion material 250 into the central hole 221, adding a binder to the expansion material 250.

[0138] Optionally, the mass percentage of the binder in the mixture of the binder and the expansion material 250 is 0.1%-10%, preferably 1%-5%.

[0139] Optionally, the binder comprises at least one of an acrylate compound, a butadiene compound, and a polyurethane compound.

[0140] Optionally, the expansion material 250 comprises a synthetic resin, and the synthetic resin comprises at least one of an epoxy resin, a phenol resin, a urea-formaldehyde resin, a melamine-formaldehyde resin, a furan resin, a silicone resin, a polyester resin, a polyamide resin, an acrylic resin, a polyurethane, a vinyl resin, a hydrocarbon resin, and a polyether resin.

[0141] Optionally, the synthetic resin is made of an olefin-ester copolymer, which includes at least one of ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer.

[0142] Optionally, the volume expansion rate of the intumescent material 250 is 5%-500%, preferably 30%-100%.

[0143] It should be understood that the battery cell 20 in any of the embodiments of the present application can be prepared by the preparation method 800 of the battery cell 20, and accordingly, the same technical effects as the aforementioned battery cell 20 can be achieved, which will not be described herein again.

[0144] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the present application, and equivalent components thereof can be substituted. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, include: case; An electrode assembly is disposed in the housing, and the electrode assembly has a central hole at its center; An expandable material is solidified within the central hole, and the expandable material is capable of expanding to support the central hole; the expandable material contains solid particles; the solid particles are hollow glass microspheres.

2. The battery cell of claim 1, wherein, The expanding material includes synthetic resins, which include at least one of epoxy resin, phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, furan resin, silicone resin, polyester resin, polyamide resin, acrylic resin, polyurethane, vinyl resin, and polyether resin.

3. The battery cell of claim 2, wherein, The synthetic resin is prepared from an olefin-ester copolymer, which includes at least one of ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, and ethylene-methacrylate copolymer.

4. The battery cell of claim 1, wherein, The volume expansion rate of the expanding material is 5%-500%.

5. The battery cell of claim 4, wherein, The volume expansion rate of the expanding material is 30%-100%.

6. The battery cell of claim 1, wherein, The volume percentage of the solid particles to the mixture of the expanding material and the solid particles is 0.1%-50%.

7. The battery cell of claim 1, wherein, The volume percentage of the solid particles and the mixture of the expanded material and the solid particles is 2%-20%.

8. The battery cell of claim 1, wherein, The mass percentage of the solid particles to the mixture of the expanding material and the solid particles is 0.5%-20%.

9. The battery cell of claim 1, wherein, The mass percentage of the solid particles to the mixture of the expanding material and the solid particles is 1%-10%.

10. The battery cell of claim 1, wherein, The particle size of the solid particles is 1 μm-2000 μm.

11. The battery cell of claim 1, wherein, The particle size of the solid particles is 5 μm-1000 μm.

12. The battery cell of claim 1, wherein, The particle size of the solid particles is 5 μm-500 μm.

13. The battery cell of claim 1, wherein, The particle size of the solid particles is 10 μm-100 μm.

14. The battery cell of claim 1, wherein, The expanded material contains a binder.

15. The battery cell of claim 14, wherein, The mass percentage of the adhesive to the mixture of the expanding material and the adhesive is 0.1%-10%.

16. The battery cell of claim 14, wherein, The mass percentage of the adhesive to the mixture of the expanding material and the adhesive is 1%-5%.

17. The battery cell of claim 14, wherein, The adhesive includes at least one of acrylate compounds, butadiene compounds, and polyurethane compounds.

18. The battery cell of any one of claims 1-17, wherein, The solidified expanded material forms a hollow support structure.

19. The battery cell of any one of claims 1-17, wherein, The solidified expanded material forms a porous support structure.

20. A battery, characterized by The battery comprises a battery cell as described in any one of claims 1-19.

21. An electrical device, comprising: The electrical device includes a battery cell as described in any one of claims 1-19 and / or a battery as described in claim 20, wherein the battery cell and / or the battery supplies power to the electrical device.

22. A method of making a battery cell, characterized by, include: An electrode assembly is provided, wherein the electrode assembly has a central hole at its center; Inject the expansion material into the central hole; After the expansion material has solidified in the central hole, the electrode assembly is placed inside the housing; Before injecting the expansion material into the central hole, solid particles, which are hollow glass microspheres, are added to the expansion material.

23. The method of claim 22, wherein, The method includes: Before the expansion material is cured in the central hole, the electrode assembly and the expansion material are dried so that the expansion material is cured in the central hole.

24. The method of claim 22, wherein, The method comprises: providing a center rod in the center hole before injecting the expansion material into the center hole; removing the center rod after the expansion material is solidified in the center hole.

25. The method of claim 22, wherein, The method comprises: stirring the expansion material to make the expansion material contain bubbles before injecting the expansion material into the center hole.

26. The method of claim 22, wherein, The volume percentage of the mixture of the solid particles and the expansion material and the solid particles is 0.1%-50%.

27. The method of claim 22, wherein, The mass percentage of the mixture of the solid particles and the expansion material and the solid particles is 0.5%-20%.

28. The method of claim 22, wherein, The particle size of the solid particles is 1 μm-2000 μm.

29. The method of claim 22, wherein, The method comprises: adding a binder to the expansion material before injecting the expansion material into the center hole.

30. The method of claim 29, wherein, The mass percentage of the mixture of the binder and the expansion material and the binder is 0.1%-10%.

31. The method of any one of claims 22-30, wherein, The expansion material comprises a synthetic resin, and the synthetic resin comprises at least one of an epoxy resin, a phenol resin, a urea-formaldehyde resin, a melamine-formaldehyde resin, a furan resin, a silicone resin, a polyester resin, a polyamide resin, an acrylic resin, a polyurethane, a vinyl resin, and a polyether resin.

32. The method of claim 31, wherein, The synthetic resin is prepared from an olefin-ester copolymer, and the olefin-ester copolymer comprises at least one of an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, and an ethylene-methacrylate copolymer.

33. The method of claim 29, wherein, The binder comprises at least one of an acrylate compound, a butadiene compound, and a polyurethane compound.

34. The method of claim 22, wherein, The expansion material has a volume expansion rate of 5%-500%.

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