Battery monomer, battery and electric device

Abstract

A battery monomer, a battery and a power utilization device, the battery monomer (71) comprising: an electrode assembly (10) comprising a positive plate (11) and a negative plate (12), the positive plate (11) comprising a positive current collector (111) and a positive active material (112) arranged on the positive current collector (111), the positive active material (112) comprising an active material capable of reversibly intercalating / deintercalating sodions, and the negative plate (12) comprising a negative active material capable of reversibly intercalating / deintercalating sodions; the negative plate (12) comprises a negative current collector (121), and the negative current collector (121) comprises a metal matrix (121b); wherein the metal matrix (121b) is made of an aluminum element, and the mass percent of the aluminum element is larger than the mass percent of other elements.

Description

Battery cells, batteries and electrical devices Technical Field

[0001] The present disclosure relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0002] With the increasing severity of environmental pollution, the new energy industry is attracting increasing attention. Battery technology is a crucial factor in the development of this industry. Research on sodium-based batteries is gaining increasing attention due to the abundance and low cost of sodium salt raw materials, as well as their more stable electrochemical performance compared to lithium-ion batteries.

[0003] Summary of the Invention

[0004] In one aspect of the present disclosure, there is provided a battery cell comprising:

[0005] An electrode assembly comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material disposed on the positive electrode current collector, wherein the positive electrode active material comprises an active material capable of reversibly extracting and inserting sodium ions, and the negative electrode sheet comprises a negative electrode current collector, wherein the negative electrode current collector comprises a metal matrix;

[0006] The metal matrix is ​​made of aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

[0007] In the related art, lithium batteries use copper foil as the negative electrode current collector, which has good conductivity, is not easily oxidized at low potential, and undergoes alloying reaction with lithium. In the sodium battery system, considering that sodium and aluminum do not undergo alloying reaction at low potential, and aluminum is cheap, it can replace copper foil to form the matrix of the negative electrode current collector. Therefore, aluminum alloy or metallic aluminum in which the mass percentage of aluminum element is greater than the mass percentage of other elements can be selected as the metal matrix of the negative electrode current collector, which can reduce cost and weight.

[0008] In some embodiments, the battery cell further comprises:

[0009] a housing having a chamber for accommodating the electrode assembly;

[0010] A negative electrode lead-out portion is provided on the outer shell and is used to electrically connect the metal substrate and a conductor outside the battery cell.

[0011] By providing a negative electrode lead-out portion, the metal substrate of the negative electrode sheet is electrically connected to the conductor outside the battery cell, and the internal and external components of the battery are electrically connected, thereby meeting the battery charging and discharging functions.

[0012] In some embodiments, the negative electrode lead-out portion is an integrally formed structure, and a constituent material of the negative electrode lead-out portion includes aluminum, and the mass percentage of the aluminum element is greater than the mass percentage of other elements.

[0013] For the negative electrode lead-out part of the one-piece molded structure, its overall constituent material includes aluminum, and the mass percentage of aluminum is greater than the mass percentage of other elements. The battery cell is electrically connected to the negative electrode current collector and the external conductor through this negative electrode lead-out part. Compared with the related art that uses copper foil as the negative electrode current collector and requires the design of a more complex copper-aluminum composite pole to be welded to the copper foil and the aluminum busbar on the inside and outside of the battery cell respectively, this negative electrode lead-out part whose main element is aluminum can achieve electrical connection with the aluminum negative electrode collector and a busbar made of pure aluminum or aluminum alloy, such as aluminum bar. It can further simplify the structure of the negative electrode lead-out part and reduce processing complexity and cost while improving the connection reliability of fixed connection methods such as welding.

[0014] In some embodiments, the constituent material of the metal substrate and the constituent material of the negative electrode lead-out portion both include aluminum in an amount greater than or equal to 90% by mass.

[0015] The constituent materials of the metal matrix of the negative electrode current collector and the constituent materials of the negative electrode lead-out part are both aluminum alloy materials or pure aluminum materials containing aluminum elements of greater than or equal to 90% by mass, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of both contain a high content of aluminum elements, it is easier to achieve a reliable connection effect during connection processes such as welding.

[0016] In some embodiments, the negative electrode lead-out portion is a split structure, and the negative electrode lead-out portion includes a fixedly connected negative electrode internal connection portion and a negative electrode external connection portion, the negative electrode internal connection portion is electrically connected to the metal substrate, and the negative electrode external connection portion is used to connect to the conductor outside the battery cell, and the constituent materials of the negative electrode internal connection portion and the negative electrode external connection portion both include aluminum element, and the mass percentage of the aluminum element is greater than the mass percentage of each other element.

[0017] The negative electrode lead-out portion is constructed of a material comprising aluminum in a greater percentage by mass than other elements, and comprises a fixedly connected negative electrode internal connection portion and a negative electrode external connection portion to achieve electrical connection to the negative electrode current collector and to an external conductor. Compared to the related art, which uses copper foil as the negative electrode current collector and requires the complex design of a copper-aluminum composite electrode column welded to the copper foil and aluminum current collector on the inside and outside of the battery cell, this negative electrode lead-out portion achieves electrical connection to the aluminum negative electrode current collector and a current collector made of pure aluminum or aluminum alloy, such as aluminum bar, through a negative electrode internal connection portion and a negative electrode external connection portion, each of which is primarily aluminum. This improves the connection reliability of fixed connection methods such as welding while further simplifying the structure of the negative electrode lead-out portion and reducing processing complexity and cost.

[0018] In some embodiments, the constituent material of the metal substrate, the constituent material of the negative electrode internal connection part, and the constituent material of the negative electrode external connection part all include aluminum elements in an amount greater than or equal to 90% by mass.

[0019] The constituent materials of the metal matrix of the negative electrode current collector and the constituent materials of the negative electrode lead-out part are both aluminum alloy materials or pure aluminum materials containing aluminum elements of greater than or equal to 90% by mass, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of both contain a high content of aluminum elements, it is easier to achieve a reliable connection effect during connection processes such as welding.

[0020] In some embodiments, the battery cell further comprises:

[0021] A negative electrode adapter, electrically connecting the metal substrate and the negative electrode lead-out portion;

[0022] The negative electrode adapter is made of a material comprising aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

[0023] A negative electrode adapter is provided to achieve the connection between the metal substrate of the negative electrode current collector and the negative electrode lead-out portion. Since the constituent materials of the metal substrate and the constituent materials of the negative electrode lead-out portion both include aluminum elements with a mass percentage greater than that of other elements, the negative electrode adapter can improve the connection reliability of fixed connection methods such as welding between the metal substrate and the negative electrode lead-out portion, simplify the structure of the negative electrode adapter, and reduce processing complexity and cost.

[0024] In some embodiments, the negative electrode adapter is made of a material that contains aluminum in an amount greater than or equal to 90% by mass.

[0025] The constituent materials of the metal matrix of the negative electrode current collector, the constituent materials of the negative electrode adapter and the constituent materials of the negative electrode lead-out part can all be aluminum alloy materials or pure aluminum materials containing aluminum elements of greater than or equal to 90% by mass, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of the three contain a high content of aluminum elements, it is easier to achieve a reliable connection effect when performing connection processes such as welding.

[0026] In some embodiments, the negative electrode current collector is composed of the metal matrix, and the constituent material of the metal matrix includes aluminum elements in an amount greater than or equal to 99% by mass.

[0027] The negative electrode current collector composed of a material including aluminum elements with a mass percentage greater than or equal to 99% is equivalent to a pure aluminum foil or a negative electrode current collector close to pure aluminum foil, which can obtain good conductivity and strong plasticity and ductility, so that it is easy to form by methods such as winding, and adapt to the expansion of the electrode assembly during charging.

[0028] In some embodiments, the negative electrode current collector further includes a first insulating material layer, the metal matrix is ​​disposed on both sides of the first insulating material layer in the thickness direction, and the constituent material of the metal matrix includes aluminum element with a mass percentage greater than or equal to 99%.

[0029] The negative electrode current collector adopts a layered composite structure, with a metal matrix composed of a material containing aluminum elements with a mass percentage of greater than or equal to 99% being arranged on both sides of the first insulating material layer. This can further reduce the weight and improve the ductility and strength of the negative electrode current collector while achieving good conductivity and strong plasticity.

[0030] In some embodiments, the battery cell further comprises:

[0031] a housing having a chamber for accommodating the electrode assembly;

[0032] A positive electrode lead-out portion, provided on the housing, for electrically connecting the positive electrode current collector and a conductor outside the battery cell;

[0033] The positive electrode lead-out portion is made of a material comprising aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

[0034] A positive electrode lead-out portion, whose primary element is aluminum, achieves electrical connection to the positive electrode current collector and can be used to connect to an external conductor. The positive electrode lead-out portion, whose primary element is aluminum, achieves electrical connection to the aluminum positive electrode current collector and a current busbar made of pure aluminum or an aluminum alloy, such as an aluminum bar. This improves the reliability of fixed connection methods such as welding while further simplifying the structure of the positive electrode lead-out portion and reducing processing complexity and cost.

[0035] In some embodiments, the positive electrode lead-out portion is formed of a material comprising aluminum in an amount greater than or equal to 90% by mass.

[0036] The positive electrode lead-out portion is made of an aluminum alloy material or pure aluminum material containing an aluminum element of greater than or equal to 90% by mass, which can more easily achieve a reliable connection effect during connection processes such as welding. In addition, the positive electrode lead-out portion has excellent conductivity and is relatively low in weight.

[0037] In some embodiments, the battery cell further comprises:

[0038] a positive electrode adapter, electrically connected to the positive electrode lead-out portion and the positive electrode current collector, respectively;

[0039] The positive electrode adapter is made of a material comprising aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

[0040] A positive electrode adapter is provided to realize the connection between the positive electrode adapter and the positive electrode current collector and the positive electrode lead-out part respectively. Since the constituent materials of the positive electrode adapter and the constituent materials of the positive electrode lead-out part both include aluminum elements with a mass percentage greater than that of other elements, the positive electrode adapter can improve the connection reliability of fixed connection methods such as welding with the positive electrode lead-out part, simplify the structure of the positive electrode adapter, and reduce processing complexity and cost.

[0041] In some embodiments, the positive electrode adapter is made of a material that contains aluminum in an amount greater than or equal to 90% by mass.

[0042] The constituent materials of the positive electrode adapter and the positive electrode lead-out part can both be aluminum alloy materials or pure aluminum materials containing aluminum elements at a mass percentage greater than or equal to 90%, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of the positive electrode adapter and the positive electrode lead-out part both contain a high content of aluminum elements, it is easier to achieve a reliable connection effect during connection processes such as welding.

[0043] In some embodiments, the positive electrode current collector is a metal current collector, and the constituent material of the metal current collector includes aluminum element in an amount greater than or equal to 99% by mass.

[0044] The positive electrode current collector, composed entirely of a material containing 99% or more aluminum by mass, is equivalent to a pure aluminum foil or a metal current collector that is nearly pure aluminum foil. This metal current collector offers excellent conductivity and strong plasticity, making it easy to form into shapes such as winding and accommodating the expansion of the electrode assembly during charging. Furthermore, this metal current collector can more easily connect to the positive electrode lead without the need for a dissimilar metal composite structure, simplifying the battery structure.

[0045] In some embodiments, the positive electrode current collector includes: a second insulating material layer and a conductive layer located on both sides of the second insulating material layer in the thickness direction of the second insulating material layer, and the constituent material of the conductive layer includes aluminum element with a mass percentage greater than or equal to 99%.

[0046] The positive electrode current collector utilizes a layered composite structure, with conductive layers composed of a material containing 99% or more aluminum by mass, disposed on both sides of the second insulating material layer. This ensures excellent conductivity and strong plasticity while further reducing weight and improving the ductility and strength of the positive electrode current collector. Furthermore, this conductive layer facilitates connection to the positive electrode lead-out portion 50, eliminating the need for a dissimilar metal composite structure and simplifying the battery structure.

[0047] In some embodiments, the housing includes a shell and a top cover, wherein one end of the shell has an end opening, and the top cover covers and is fixed to the end opening;

[0048] Wherein, the top cover is electrically connected to the metal substrate as the negative electrode lead-out portion and is used to connect to the conductor outside the battery cell; the shell wall of the shell is electrically connected to the positive electrode current collector as the positive electrode lead-out portion and is used to connect to the conductor outside the battery cell; or

[0049] The top cover serves as the positive electrode lead-out portion, electrically connected to the positive electrode current collector, and is used to connect to the conductor outside the battery cell; the shell wall of the shell serves as the negative electrode lead-out portion, electrically connected to the metal substrate, and is used to connect to the conductor outside the battery cell.

[0050] For the negative electrode lead-out portion of the integrally molded structure, using the top cover as the negative electrode lead-out portion to electrically connect to the metal substrate and the external conductor can provide a larger electrical connection area for the negative electrode lead-out portion, reduce internal resistance, and be more simple in structure, occupying less space, which is conducive to further improving the battery capacity. Using the shell wall as the positive electrode lead-out portion to connect the positive electrode current collector and the external conductor can also provide a larger electrical connection area for the positive electrode lead-out portion, reduce internal resistance, and facilitate connection to the external conductor.

[0051] Similarly, for the negative electrode lead of an integrally molded structure, using the shell wall as the negative electrode lead to electrically connect to the metal substrate and the external conductor can provide a larger electrical connection area for the negative electrode lead, reduce internal resistance, and be more simple in structure, occupying less space, which is conducive to further improving battery power. Using the top cover as the positive electrode lead to connect the positive electrode current collector and the external conductor can also provide a larger electrical connection area for the positive electrode lead, reduce internal resistance, and facilitate connection to the external conductor.

[0052] In some embodiments, the housing includes a shell, a first top cover and a second top cover, the shell has end openings at opposite ends, and the first top cover and the second top cover respectively cover and are fixed to the end openings at opposite ends of the shell;

[0053] Wherein, the first top cover is electrically connected to the metal substrate as the negative electrode lead-out portion and is used to connect to the conductor outside the battery cell; the second top cover is electrically connected to the positive electrode current collector as the positive electrode lead-out portion and is used to connect to the conductor outside the battery cell; or

[0054] The second top cover is electrically connected to the metal substrate as the negative electrode lead-out portion and is used to connect to the conductor outside the battery cell; the first top cover is electrically connected to the positive electrode collector as the positive electrode lead-out portion and is used to connect to the conductor outside the battery cell.

[0055] For the negative electrode lead-out portion of the integrally molded structure, the first top cover is used as the negative electrode lead-out portion to electrically connect to the metal substrate and the external conductor. This allows the negative electrode lead-out portion to have a larger electrical connection area, reduces internal resistance, and is structurally simpler, taking up less space, which helps further increase battery power. The second top cover is used as the positive electrode lead-out portion to connect the positive electrode current collector and the external conductor. This allows the positive electrode lead-out portion to have a larger electrical connection area, reduces internal resistance, and facilitates connection to the external conductor.

[0056] Similarly, for the negative electrode lead-out portion of the integrally molded structure, using the second top cover as the negative electrode lead-out portion to electrically connect to the metal substrate and the external conductor can provide the negative electrode lead-out portion with a larger electrical connection area, reduce internal resistance, and be more simple in structure, occupying less space, which is conducive to further improving battery power. Using the first top cover as the positive electrode lead-out portion to connect the positive electrode current collector and the external conductor can provide the positive electrode lead-out portion with a larger electrical connection area, reduce internal resistance, and facilitate connection to the external conductor.

[0057] In some embodiments, the positive electrode active material includes at least one of a sodium-containing layered transition metal oxide, a sodium-containing phosphate, and a Prussian blue analogue.

[0058] The use of a positive electrode active material comprising at least one of a sodium-containing layered transition metal oxide, a sodium-containing phosphate, and a Prussian blue analogue can achieve reversible extraction and insertion of sodium ions.

[0059] In one aspect of the present disclosure, a battery is provided, comprising: the aforementioned battery cell.

[0060] A battery using the aforementioned battery cells can reduce weight and cost.

[0061] In some embodiments, the battery includes a plurality of battery cells and further includes a busbar for electrically connecting the plurality of battery cells, wherein a constituent material of the busbar includes aluminum in a greater mass percentage than other elements.

[0062] The plurality of battery cells are electrically connected by a busbar whose constituent material includes aluminum in a larger mass percentage than other elements. The busbar can be more easily and reliably welded to the negative electrode lead-out portion whose constituent material includes aluminum in a larger mass percentage than other elements.

[0063] In some embodiments, the material constituting the current bus includes aluminum in an amount greater than or equal to 90% by mass.

[0064] The busbar is made of an aluminum alloy material or pure aluminum material containing aluminum elements in an amount greater than or equal to 90% by mass, which can more easily achieve a reliable connection effect during connection processes such as welding.

[0065] In one aspect of the present disclosure, there is provided an electrical device comprising: the aforementioned battery.

[0066] The electric device using the above-mentioned battery can reduce weight and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on the drawings without any creative work.

[0068] The present disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0069] FIG1 is a schematic structural diagram of some embodiments of an electric device according to the present disclosure;

[0070] FIG2 is an exploded schematic diagram of some embodiments of batteries according to the present disclosure;

[0071] FIG3 is a schematic diagram of the connection of multiple battery cells in some embodiments of the battery according to the present disclosure;

[0072] FIG4 is a schematic structural diagram of some embodiments of a battery cell according to the present disclosure;

[0073] FIG5 is an exploded schematic diagram of the embodiment shown in FIG4 ;

[0074] FIG6 is a schematic cross-sectional view of the embodiment shown in FIG4 ;

[0075] FIG7 is a schematic diagram illustrating the arrangement of a positive electrode sheet, a negative electrode sheet, and a separator included in an electrode assembly according to some embodiments of a battery cell of the present disclosure;

[0076] FIG8 is a schematic cross-sectional view of a negative electrode current collector in some embodiments of a battery cell according to the present disclosure;

[0077] FIG9 is a schematic cross-sectional view of a negative electrode current collector in other embodiments of a battery cell according to the present disclosure;

[0078] FIG10 is a schematic cross-sectional view of a positive electrode current collector in some embodiments of a battery cell according to the present disclosure;

[0079] FIG11 is a schematic cross-sectional view of a positive electrode current collector in other embodiments of a battery cell according to the present disclosure;

[0080] FIG12 is a schematic cross-sectional view of other embodiments of battery cells according to the present disclosure;

[0081] FIG13 is an exploded schematic diagram of other embodiments of batteries according to the present disclosure;

[0082] FIG14 is a schematic diagram showing the connection of multiple battery cells in other embodiments of the battery according to the present disclosure;

[0083] FIG15 is a schematic structural diagram of other embodiments of battery cells according to the present disclosure;

[0084] FIG16 is an exploded schematic diagram of the embodiment shown in FIG15 ;

[0085] FIG17 is a schematic cross-sectional view of the embodiment shown in FIG15 ;

[0086] FIG18 is a schematic structural diagram of further embodiments of a battery cell according to the present disclosure;

[0087] FIG19 is an exploded schematic diagram of the embodiment shown in FIG18 ;

[0088] FIG20 is a schematic cross-sectional view of the embodiment shown in FIG18 ;

[0089] FIG21 is an exploded schematic diagram of another embodiment with reference to FIG19 ;

[0090] FIG22 is a schematic structural diagram of further embodiments of a battery cell according to the present disclosure;

[0091] FIG23 is an exploded schematic diagram of the embodiment shown in FIG22 ;

[0092] FIG24 is a schematic cross-sectional view of the embodiment shown in FIG22 ;

[0093] FIG. 25 is an exploded schematic diagram of another embodiment with reference to FIG. 23 .

[0094] It should be understood that the size of each part shown in the drawings is not drawn according to the actual proportional relationship.In addition, the same or similar reference numerals represent the same or similar components.

[0095] Description of reference numerals:

[0096] 10 - electrode assembly; 11 - positive electrode sheet; 111 - positive electrode current collector; 111i - second insulating material layer; 111c - conductive layer; 112 - positive electrode active material; 12 - negative electrode sheet; 121 - negative electrode current collector; 121b - metal substrate; 121i - first insulating material layer; 13 - separator;

[0097] 20-housing; 21-shell; 22-top cover; 22a-first top cover; 22b-second top cover;

[0098] 30- negative electrode lead-out portion; 31- negative electrode internal connection portion; 32- negative electrode external connection portion;

[0099] 40-negative electrode adapter;

[0100] 50-positive electrode lead-out portion; 51-positive electrode internal connection portion; 52-positive electrode external connection portion;

[0101] 60-positive electrode adapter;

[0102] 70 - battery; 71 - electrode monomer; 72 - busbar; 73 - box body; 74 - box cover;

[0103] 80-Vehicle; 81-Controller; 82-Motor. DETAILED DESCRIPTION

[0104] The following detailed description of the embodiments of the present disclosure is provided in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of the present disclosure, but are not intended to limit the scope of the present disclosure, that is, the present disclosure is not limited to the described embodiments.

[0105] In the description of the present disclosure, it should be noted that, unless otherwise specified, the meaning of "multiple" is more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present disclosure. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0106] The directional words appearing in the following description are all directions shown in the figures and do not limit the specific structure of the present disclosure. In the description of the present disclosure, 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 those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0107] The following describes some embodiments of the present disclosure in detail with reference to the accompanying drawings. In the absence of conflict, the features of the following embodiments can be combined with each other.

[0108] The term "plurality" appearing in the present disclosure refers to two or more (including two).

[0109] In the embodiment of the present disclosure, 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.

[0110] In the prior art, lithium-ion batteries use copper foil as the negative electrode current collector, as it has good conductivity, is not easily oxidized at low potentials, and does not easily alloy with lithium. However, for sodium-based batteries that continue to use copper foil, the material cost needs to be further reduced.

[0111] In view of this, embodiments of the present disclosure provide a battery cell, a battery, and an electrical device, which are beneficial for reducing the material cost of the battery cell.

[0112] In one aspect of the present disclosure, a battery cell is provided, comprising: an electrode assembly, the electrode assembly comprising a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode active material disposed on the positive electrode current collector, the positive electrode active material comprising an active material capable of reversibly extracting and embedding sodium ions, the negative electrode sheet comprising a negative electrode current collector, the negative electrode current collector comprising a metal matrix; wherein the constituent material of the metal matrix comprises aluminum, and the mass percentage of the aluminum element is greater than the mass percentage of each other element.

[0113] In the related art, lithium batteries use copper foil as the negative electrode current collector, which has good conductivity and is not easily oxidized and alloyed with Li at low potentials. In contrast, in the sodium battery system, sodium and aluminum do not undergo alloying reactions at low potentials, and aluminum is cheap. Therefore, aluminum alloys or metallic aluminum in which the mass percentage of aluminum is greater than the mass percentage of other elements can be selected as the metal matrix of the negative electrode current collector to replace copper foil, thereby reducing costs and weight.

[0114] Figure 1 is a schematic diagram of the structure of some embodiments of electrical devices according to the present disclosure. For convenience, the description uses a vehicle as an example. Vehicle 80 can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle or a hybrid vehicle. Battery 70 can be installed at the bottom, front, or rear of vehicle 80.

[0115] Battery 70 can be used to power vehicle 80. For example, battery 70 can serve as the operating power source for vehicle 80 and the circuit system of vehicle 80, such as the power required for starting, navigation, and operation of vehicle 80. Battery 70 can not only serve as the operating power source for vehicle 80, but also as the driving power source for vehicle 80, replacing or partially replacing fuel or natural gas to provide driving force for vehicle 80.

[0116] The vehicle 80 may also be provided with axles, wheels, a motor 82, and a controller 81. The controller 81 is used to control the battery 70 to power the motor 82. For example, when the vehicle 80 is powered by the battery 70, the controller 81 can provide the motor 82 with the power required for uniform speed and acceleration. The motor 82 is used to drive the axles to rotate, thereby driving the wheels to rotate.

[0117] FIG2 is a schematic diagram of an exploded view of some embodiments of the battery according to the present disclosure. FIG3 is a schematic diagram of the connection of multiple battery cells according to some embodiments of the battery according to the present disclosure. Referring to FIG2 and FIG3, in some embodiments, a battery 70 includes a battery box and multiple battery cells 72 disposed within the battery box. The battery box can provide the battery cells 72 with functions such as accommodation, support, cooling, sealing, and impact protection, and can also prevent external liquids or other foreign matter from adversely affecting the charging, discharging, or safety of the battery cells. The battery box may include a box body 73 and a box cover 74 that snaps into place with the box body 73.

[0118] 3 , the individual battery cells 71 can be electrically connected via busbars 72, such as in series, parallel, or hybrid, to achieve the desired electrical performance parameters of the battery 70. Multiple battery cells 71 are arranged in rows, and one or more rows of battery cells 71 can be arranged in the housing as needed.

[0119] In some embodiments, the battery cells 71 of the battery 70 may be arranged along at least one of the length and width of the battery case. Depending on actual needs, at least one row or column of battery cells 71 may be provided. Alternatively, one or more layers of battery cells 71 may be provided along the height of the battery 70 as needed.

[0120] In some embodiments, multiple battery cells 71 may be connected in series, parallel, or hybrid to form a battery module, and then the multiple battery modules may be connected in series, parallel, or hybrid to form a whole unit and housed in a battery box. In other embodiments, all battery cells 71 may be directly connected in series, parallel, or hybrid to form a whole unit and then housed in a battery box.

[0121] Figure 4 is a schematic diagram of the structure of some embodiments of a battery cell according to the present disclosure. Figure 5 is an exploded schematic diagram of the embodiment shown in Figure 4. Figure 6 is a cross-sectional schematic diagram of the embodiment shown in Figure 4. Figure 7 is a schematic diagram of the arrangement of the positive electrode sheet, negative electrode sheet, and separator included in the electrode assembly according to some embodiments of a battery cell according to the present disclosure.

[0122] With reference to Figures 4-6, an embodiment of the present disclosure provides a battery cell 71 including an electrode assembly 10. With reference to Figure 7, the electrode assembly 10 includes a positive electrode sheet 11 and a negative electrode sheet 12. The positive electrode sheet 11 includes a positive electrode current collector 111 and a positive electrode active material 112 disposed on the positive electrode current collector 111. The positive electrode active material 112 includes an active material capable of reversibly extracting and inserting sodium ions. The negative electrode sheet 12 includes a negative electrode current collector 121, which includes a metal substrate 121b. The constituent material of the metal substrate 121b includes aluminum, and the mass percentage of the aluminum element is greater than the mass percentage of the other elements.

[0123] In this embodiment, the other elements in the constituent material of the metal matrix except aluminum element may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt, and rare earth elements, and may also include elements as impurities.

[0124] In the sodium battery system, sodium and aluminum do not undergo an alloying reaction at low potentials, and aluminum is inexpensive. Selecting an aluminum alloy or metallic aluminum with a mass percentage of aluminum element greater than that of other elements as the metal matrix 121b of the negative electrode current collector 121 to replace the copper foil to form the matrix of the negative electrode current collector 121 can reduce the material cost of the battery cell and reduce the weight.

[0125] The mass percentage of aluminum element can be measured by a spectrometer, for example, the mass percentage of aluminum element in a sample is measured by a direct-reading spectrometer. In a measurement example, the sample is placed on the excitation stage of the photoelectric direct-reading spectrometer, and the inspected surface of the sample is polished. The sample is excited one or more times after the machine is turned on. After the sample is excited by the excitation source on the excitation stage, the characteristic spectra of each element are generated through the condenser and the linear motor. The spectral lines of various elements are automatically arranged by grating spectroscopy to form the spectral lines of each element, and then irradiated on the photomultiplier tube through the exit slit, converted into a photocurrent through the photomultiplier tube, and the content of the measured element is finally obtained through data processing using the relationship between the photocurrent, the spectral intensity of the element, and the element content.

[0126] The positive electrode current collector 111 has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material 112 is provided on either or both of the two opposite surfaces of the positive electrode current collector 111. In some embodiments, the positive electrode current collector may be in the form of a metal foil or a composite current collector.

[0127] In this embodiment, the positive electrode active material may be an active material well-known in the art that can reversibly deintercalate-insert sodium ions in the sodium battery system.

[0128] In some embodiments, the positive electrode active material 112 includes at least one of sodium-containing layered transition metal oxides, sodium-containing phosphates, and Prussian blue analogs.

[0129] Optionally, the sodium-containing layered transition metal oxide includes a substance with the general formula NafMgFehO2, M includes at least one of the transition metal elements, 0.67 < f < 1.1, 0.5 < g < 1, 0 < h < 0.5. For example, the sodium-containing layered transition metal oxide can be Na 0.24 Cu 0.24 Fe 0.29 Mn 0.47 O2.

[0130] Optionally, the sodium-containing phosphate includes a substance with the general formula Na e Me c (PO4) d O2X, where Me includes at least one of the transition metal elements, X includes at least one of the halogen elements, 0 < e ≤ 4, 0 < c ≤ 2, and 1 ≤ d ≤ 3. In some embodiments, the sodium-containing phosphate can be Na3V2(PO4)2O2F.

[0131] Optionally, the Prussian blue analog includes a substance with the general formula Na x P[R(CN)6]δ·zH2O, where P and R each independently include at least one of the transition metal elements, 0 < x ≤ 2, 0 < δ ≤ 1, and 0 ≤ z ≤ 10. In some embodiments, the Prussian blue analog can be Na2Ni 0.17 Co 0.83 Fe(CN)6.

[0132] Optionally, the transition metal elements include at least one of Ti, Cr, Mn, Fe, Co, Ni, V, Cu, and Zn.

[0133] Optionally, the halogen elements include at least one of F, Cl, and Br.

[0134] In some embodiments, the positive electrode active material can be dispersed with a conductive agent, a binder, and any other components in a solvent to form a positive electrode paste coated on the surface of the positive electrode current collector. Among them, as an example, the binder can include at least one of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin. As an example, the conductive agent can include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0135] Referring to FIG. 7, the negative electrode sheet 12 includes a negative electrode current collector 121 and a negative electrode active material provided on at least one surface of the negative electrode current collector 121. As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material is provided on any one or both of the two opposite surfaces of the negative electrode current collector. In some other embodiments, no negative electrode active material is provided on the negative electrode current collector.

[0136] In some embodiments, the negative electrode current collector can be a metal foil or a composite current collector.

[0137] In some embodiments, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. 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. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0138] 5 and 6 , in some embodiments, the battery cell 71 further includes a housing 20 and a negative electrode lead-out portion 30. The housing 20 has a chamber for accommodating the electrode assembly 10. The negative electrode lead-out portion 30 is disposed on the housing 20. The negative electrode lead-out portion 30 is used to electrically connect the metal substrate 121b to a conductor external to the battery cell 71.

[0139] The external conductor of the battery cell 71 can be a conductive portion of an electrical device or a charging device. Alternatively, the external conductor can be a busbar for electrically connecting multiple battery cells. The negative electrode lead-out portion is provided to electrically connect the metal substrate of the negative electrode sheet to the external conductor of the battery cell, achieving electrical continuity between the internal and external components of the battery, thereby satisfying the battery's charge and discharge functions.

[0140] In some related lithium-ion batteries, the positive and negative current collectors are made of aluminum and copper, respectively. When such lithium-ion battery cells are connected to the poles through a busbar (such as an aluminum bar), copper-aluminum welding is difficult (mainly due to the large difference in their melting points, copper is 1083.4°C and aluminum is 660°C). Therefore, a copper-aluminum composite pole structure is usually adopted, that is, the copper pole portion of the copper-aluminum composite pole is connected to the copper negative current collector, and the aluminum pole portion is welded to the aluminum bar to ensure the reliability of the electrical connection. However, this copper-aluminum composite structure is relatively complex to process and has high costs. In addition, electrochemical reactions may occur at the copper-aluminum connection, resulting in increased resistance at the contact point.

[0141] 6 , in some embodiments, the negative electrode lead-out portion 30 is a split structure, and the negative electrode lead-out portion 30 includes a fixedly connected negative electrode internal connection portion 31 and a negative electrode external connection portion 32, wherein the negative electrode internal connection portion 31 is electrically connected to the metal substrate 121 b, and the negative electrode external connection portion 32 is used to connect to the conductor outside the battery cell 71, and the constituent materials of the negative electrode internal connection portion 31 and the negative electrode external connection portion 32 both include aluminum element, and the mass percentage of the aluminum element is greater than the mass percentage of each other element.

[0142] In this embodiment, the elements other than aluminum in the constituent materials of the negative electrode internal connection part and the constituent materials of the negative electrode external connection part may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt and rare earth elements, and may also include elements as impurities.

[0143] The negative electrode lead-out portion 30 is constructed of a material comprising aluminum in a greater percentage by mass than other elements, and comprises a fixedly connected negative electrode internal connection portion 31 and a negative electrode external connection portion 32, achieving electrical connection to the negative electrode current collector 121 and also connecting to an external conductor. Compared to the related art, which uses copper foil as the negative electrode current collector 121 and requires the complex design of a copper-aluminum composite electrode column welded to the copper foil and aluminum current collector 72 on the inner and outer sides of the battery cell 71, this negative electrode lead-out portion 30 achieves electrical connection to the aluminum negative electrode current collector 121 and the current collector 72, which is made of pure aluminum or an aluminum alloy such as aluminum bar, through the negative electrode internal connection portion 31 and the negative electrode external connection portion 32, respectively. This improves the connection reliability of fixed connection methods such as welding, further simplifies the structure of the negative electrode lead-out portion 30, and reduces processing complexity and cost.

[0144] For the embodiment in which the negative electrode internal connection part and the negative electrode external connection part are integrally formed, the integrally formed negative electrode lead-out part has good conductivity and eliminates the connection operation between the negative electrode internal connection part and the negative electrode external connection part, which is beneficial to saving process steps.

[0145] In some embodiments, the constituent material of the metal substrate 121 b , the constituent material of the negative electrode internal connection portion 31 , and the constituent material of the negative electrode external connection portion 32 all include aluminum elements in an amount greater than or equal to 90% by mass.

[0146] The constituent materials of the metal base 121b of the negative electrode current collector 121 and the constituent materials of the negative electrode lead-out portion 30 are both aluminum alloy materials or pure aluminum materials containing aluminum elements in an amount greater than or equal to 90% by mass, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of both contain a high content of aluminum elements, it is easier to achieve a reliable connection effect when performing connection processes such as welding.

[0147] 5 and 6 , in some embodiments, the battery cell 71 further includes a negative electrode adapter 40. The negative electrode adapter 40 electrically connects the metal substrate 121b and the negative electrode lead-out portion 30. The negative electrode adapter 40 is made of aluminum, with the mass percentage of aluminum being greater than the mass percentages of the other elements.

[0148] In this embodiment, the elements other than aluminum in the constituent materials of the negative electrode adapter may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt, and rare earth elements, and may also include elements as impurities.

[0149] A negative electrode adapter 40 is provided to achieve the connection between the metal base 121b of the negative electrode current collector 121 and the negative electrode lead-out portion 30. Since the constituent materials of the metal base 121b and the constituent materials of the negative electrode lead-out portion 30 both include aluminum elements with a mass percentage greater than that of other elements, the negative electrode adapter 40 can improve the connection reliability of fixed connection methods such as welding between the metal base 121b and the negative electrode lead-out portion 30, simplify the structure of the negative electrode adapter, and reduce processing complexity and cost.

[0150] In Figures 5 and 6 , the negative electrode adapter 40 can be configured in a bent structure to facilitate welding to the negative electrode current collector 121 and the negative internal connection portion 31 of the negative electrode lead-out portion 30, respectively, located in different directions of the electrode assembly. In other embodiments, the battery cell 71 may not include the negative electrode adapter 40, and the negative electrode current collector 121 may be welded to the negative internal connection portion 31 of the negative electrode lead-out portion 30.

[0151] In some embodiments, the negative electrode adapter 40 is made of a material that contains aluminum in an amount greater than or equal to 90% by mass.

[0152] The constituent materials of the metal base 121b of the negative electrode current collector 121, the constituent materials of the negative electrode adapter 40 and the constituent materials of the negative electrode lead-out portion 30 can all be aluminum alloy materials or pure aluminum materials containing aluminum elements in an amount greater than or equal to 90% by mass, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of the three contain a high content of aluminum elements, it is easier to achieve a reliable connection effect when performing connection processes such as welding.

[0153] FIG8 is a cross-sectional view of a negative electrode current collector in some embodiments of a battery cell according to the present disclosure. Referring to FIG7 and FIG8 , the negative electrode current collector 121 is composed of the metal substrate 121b, and the constituent material of the metal substrate 121b includes aluminum in an amount greater than or equal to 99% by mass.

[0154] The negative electrode current collector 121 composed of a material including aluminum elements with a mass percentage greater than or equal to 99% is equivalent to a pure aluminum foil or a negative electrode current collector 121 close to pure aluminum foil, which can obtain good conductivity and strong plasticity and ductility, so that it is easy to form by methods such as winding, and adapt to the expansion of the electrode assembly 10 during charging.

[0155] Figure 9 is a schematic cross-sectional view of a negative electrode current collector according to other embodiments of a battery cell according to the present disclosure. Referring to Figure 9 , the negative electrode current collector 121 further includes a first insulating material layer 121i , with the metal substrate 121b disposed on either side of the first insulating material layer 121i along the thickness direction. The metal substrate 121b is composed of a material comprising greater than or equal to 99% aluminum by mass.

[0156] The first insulating material layer 121i can be formed from a polymeric substrate, such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene. The negative electrode current collector 121 employs a layered composite structure, with a metal substrate 121b composed of a material containing 99% or more of aluminum by mass disposed on both sides of the first insulating material layer 121i. This achieves excellent conductivity and strong plasticity while further reducing weight and improving the ductility and strength of the negative electrode current collector 121.

[0157] Referring to Figures 4-6 , in some embodiments, the battery cell 71 further includes a housing 20 and a positive electrode lead-out portion 50 . The housing 20 has a chamber for accommodating the electrode assembly 10. The positive electrode lead-out portion 50 is disposed on the housing 20 and is used to electrically connect the positive electrode current collector 111 to a conductor external to the battery cell 71. The positive electrode lead-out portion 50 is formed from aluminum, with the mass percentage of aluminum being greater than the mass percentage of the other elements.

[0158] In this embodiment, the elements other than aluminum in the constituent material of the positive electrode lead-out portion may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt and rare earth elements, and may also include elements as impurities.

[0159] A positive electrode lead-out portion, whose primary element is aluminum, achieves electrical connection to the positive electrode current collector and can be used to connect to an external conductor. The positive electrode lead-out portion, whose primary element is aluminum, achieves electrical connection to the aluminum positive electrode current collector and a current busbar made of pure aluminum or an aluminum alloy, such as an aluminum bar. This improves the reliability of fixed connection methods such as welding while further simplifying the structure of the positive electrode lead-out portion and reducing processing complexity and cost.

[0160] 6 , in some embodiments, the positive electrode lead-out portion 50 is a split structure, which includes a positive electrode internal connection portion 51 and a positive electrode external connection portion 52. The positive electrode internal connection portion 51 is electrically connected to the positive electrode current collector 111, and the positive electrode external connection portion 52 is used to connect to the conductor outside the battery cell 71. The positive electrode external connection portion 52 is integrally formed with the positive electrode internal connection portion 51, or is in contact with and electrically connected to the positive electrode internal connection portion 51. The constituent materials of the positive electrode internal connection portion 51 and the constituent materials of the positive electrode external connection portion 52 both include aluminum element, and the mass percentage of the aluminum element is greater than the mass percentage of each other element.

[0161] In this embodiment, the elements other than aluminum in the constituent materials of the positive electrode internal connection part 51 and the constituent materials of the positive electrode external connection part 52 may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt and rare earth elements, and may also include elements as impurities.

[0162] The positive electrode lead-out portion 50 utilizes a positive electrode internal connection portion 51 and a positive electrode external connection portion 52, each composed of aluminum, which has a higher mass percentage than other elements, to achieve electrical connection with the positive electrode current collector 111 and can also be used to connect to an external conductor. The positive electrode lead-out portion 50 utilizes the aluminum-based positive electrode internal connection portion 51 and the aluminum external connection portion 52 to respectively achieve electrical connection with the aluminum positive electrode current collector 111 and the current bus 72, which is made of pure aluminum or an aluminum alloy such as aluminum bar. This improves the reliability of fixed connection methods such as welding while further simplifying the structure of the positive electrode lead-out portion 50 and reducing manufacturing complexity and cost.

[0163] In some embodiments, the positive electrode lead-out portion 50 is made of a material that contains aluminum in an amount greater than or equal to 90% by mass.

[0164] The positive electrode lead-out portion 50 is made of an aluminum alloy material or pure aluminum material containing an aluminum element of 90% by mass or more, which can more easily achieve a reliable connection effect during connection processes such as welding. In addition, the positive electrode lead-out portion 50 has excellent conductivity and is relatively low in weight.

[0165] 5 and 6 , in some embodiments, the battery cell 71 further includes a positive electrode adapter 60. The positive electrode adapter 60 is electrically connected to the positive electrode lead-out portion 50 and the positive electrode current collector 111. The positive electrode adapter 60 is made of aluminum, with the mass percentage of aluminum being greater than the mass percentages of the other elements.

[0166] In this embodiment, the elements other than aluminum in the constituent materials of the positive electrode adapter may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt and rare earth elements, and may also include elements as impurities.

[0167] A positive electrode adapter 60 is provided to achieve connection between the positive electrode adapter 60 and the positive electrode current collector 111 and the positive electrode lead-out portion 50, respectively. Since the constituent materials of the positive electrode adapter 60 and the constituent materials of the positive electrode lead-out portion 50 both include aluminum elements with a mass percentage greater than that of other elements, the positive electrode adapter 60 can improve the connection reliability of fixed connection methods such as welding with the positive electrode lead-out portion 50, simplify the structure of the positive electrode adapter, and reduce processing complexity and cost.

[0168] In some embodiments, the positive electrode adapter 60 is made of a material that contains aluminum in an amount greater than or equal to 90% by mass.

[0169] The constituent materials of the positive electrode adapter 60 and the positive electrode lead-out portion 50 can both be aluminum alloy materials or pure aluminum materials containing aluminum elements in an amount greater than or equal to 90% by mass, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of the positive electrode adapter 60 and the positive electrode lead-out portion 50 both contain a high content of aluminum elements, it is easier to achieve a reliable connection effect when performing connection processes such as welding.

[0170] FIG10 is a cross-sectional view of a positive electrode current collector in some embodiments of a battery cell according to the present disclosure. Referring to FIG7 and FIG10 , in some embodiments, the positive electrode current collector 111 is a metal current collector, and the constituent material of the metal current collector includes aluminum in an amount greater than or equal to 99% by mass.

[0171] The positive electrode current collector 111, composed entirely of a material containing 99% or more by mass of aluminum, is equivalent to a pure aluminum foil or a metal current collector that is nearly pure aluminum foil. This metal current collector exhibits excellent conductivity and strong plasticity, making it easy to form into shapes such as winding and accommodating the expansion of the electrode assembly 10 during charging. Furthermore, this metal current collector can more easily connect to the positive electrode lead-out portion 50 without the need for a composite structure of dissimilar metals, simplifying the battery structure.

[0172] Figure 11 is a schematic cross-sectional view of a positive electrode current collector according to other embodiments of a battery cell according to the present disclosure. Referring to Figures 7 and 11, in some embodiments, the positive electrode current collector 111 includes: a second insulating material layer 111i and conductive layers 111c located on both sides of the second insulating material layer 111i in the thickness direction of the second insulating material layer 111i, wherein the conductive layer 111c is composed of a material containing aluminum at a mass percentage of greater than or equal to 99%.

[0173] The second insulating material layer 111i can be composed of a polymer substrate, such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like. The positive electrode current collector 111 utilizes a layered composite structure, with conductive layers 111c composed of a material containing 99% or more aluminum by mass disposed on both sides of the second insulating material layer 111i. This achieves excellent conductivity and strong plasticity while further reducing weight and improving the ductility and strength of the positive electrode current collector 111. Furthermore, this conductive layer 111c facilitates connection to the positive electrode lead-out portion 50, eliminating the need for a dissimilar metal composite structure and simplifying the battery structure.

[0174] Figures 3-6 illustrate some embodiments of a prismatic battery cell 71. The electrode assembly 10 extends from both ends in the first direction dr1, extending from the portion of the negative electrode current collector 121 not covered by the negative electrode active material 122 (i.e., the negative electrode tab) and the portion of the positive electrode current collector 111 not covered by the positive electrode active material 112 (i.e., the positive electrode tab). The negative electrode lead 30 and the positive electrode lead 50 are located on the same side of the electrode assembly 10 in the third direction dr3.

[0175] In Figure 5 , the first direction dr1 and the second direction dr2 are perpendicular to each other and are both perpendicular to the third direction dr3. The housing 21 of the outer casing 20 has an open end on one side of the third direction dr3. The second direction dr2 is parallel to the thickness direction of the electrode assembly 10. The negative electrode tab and the positive electrode tab are located at both ends of the electrode assembly 10 along the first direction dr1.

[0176] The negative electrode lead-out portion 30 is welded to the negative electrode tab and the negative electrode internal connection portion 31 of the negative electrode lead-out portion 30 through a bent negative electrode adapter 40. The negative electrode external connection portion 32 of the negative electrode lead-out portion 30 is located on the side of the negative electrode internal connection portion 31 away from the electrode assembly 10 and is used for electrical connection to an external conductor. The positive electrode lead-out portion 50 is welded to the positive electrode tab and the positive electrode internal connection portion 51 of the positive electrode lead-out portion 50 through a bent positive electrode adapter 60. The positive electrode external connection portion 52 of the positive electrode lead-out portion 50 is located on the side of the positive electrode internal connection portion 51 away from the electrode assembly 10 and is used for electrical connection to an external conductor.

[0177] Figure 12 is a schematic cross-sectional view of other embodiments of a battery cell according to the present disclosure. Figure 12 shows the cross-sectional structures of other embodiments of a square-shell battery cell. The portion of the negative electrode current collector 121 not covered by the negative electrode active material 122 (i.e., the negative electrode tab) and the portion of the positive electrode current collector 111 not covered by the positive electrode active material 112 (i.e., the positive electrode tab) extend from the same end of the electrode assembly 10 in the third direction dr3. The negative electrode lead-out portion 30 and the positive electrode lead-out portion 50 are also located on the same side of the electrode assembly 10 in the third direction dr3 and are adjacent to the negative electrode tab and the positive electrode tab. The negative electrode lead-out portion 30 is welded to the negative electrode tab and the negative electrode lead-out portion 30 respectively through the negative electrode adapter 40. The positive electrode lead-out portion 50 is welded to the positive electrode tab and the positive electrode lead-out portion 50 respectively through the positive electrode adapter 60.

[0178] 12 , in some embodiments, the negative electrode lead-out portion 30 is an integrally formed structure, and the constituent material of the negative electrode lead-out portion 30 includes aluminum, and the mass percentage of the aluminum element is greater than the mass percentage of other elements.

[0179] In this embodiment, the elements other than aluminum in the constituent materials of the negative electrode lead-out portion of the integrally molded structure may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt and rare earth elements, and may also include elements serving as impurities.

[0180] For the negative electrode lead-out part 30 of the one-piece molded structure, its overall constituent material includes aluminum, and the mass percentage of aluminum is greater than the mass percentage of other elements. The battery cell is electrically connected to the negative electrode current collector and the external conductor through this negative electrode lead-out part 30. Compared with the related art that uses copper foil as the negative electrode current collector and requires the design of a more complex copper-aluminum composite pole to be welded to the copper foil and the aluminum busbar on the inside and outside of the battery cell respectively, this negative electrode lead-out part 30 whose main element is aluminum can achieve electrical connection with the aluminum negative electrode current collector and a busbar made of pure aluminum or aluminum alloy, such as aluminum bar. While improving the connection reliability of fixed connection methods such as welding, it can further simplify the structure of the negative electrode lead-out part 30 and reduce processing complexity and cost.

[0181] In some embodiments, the constituent material of the metal base 121 b and the constituent material of the negative electrode lead-out portion 30 both include aluminum in an amount greater than or equal to 90% by mass.

[0182] The constituent materials of the metal matrix of the negative electrode current collector and the constituent materials of the negative electrode lead-out part are both aluminum alloy materials or pure aluminum materials containing aluminum elements of greater than or equal to 90% by mass, so as to achieve better conductivity and reduce weight. In addition, since the constituent materials of both contain a high content of aluminum elements, it is easier to achieve a reliable connection effect during connection processes such as welding.

[0183] To facilitate installation of the negative lead-out portion 30 , the negative lead-out portion 30 is fixed to the side of the top cover 22 of the outer shell 20 away from the electrode assembly 10 , and the negative electrode adapter 40 is formed with a protrusion passing through the through hole on the top cover 22 for welding to the negative lead-out portion 30 .

[0184] Referring to Figure 12 , in some embodiments, the positive electrode lead-out portion 50 is an integrally formed structure. This integrally formed structure provides excellent electrical conductivity and eliminates the need for connecting the positive electrode internal and external connections, thereby saving process steps. Accordingly, the positive electrode lead-out portion 50 is formed from a material comprising aluminum, wherein the mass percentage of aluminum is greater than the mass percentages of the other elements. Optionally, the positive electrode lead-out portion 50 comprises aluminum at a mass percentage of greater than or equal to 90%.

[0185] In this embodiment, the elements other than aluminum in the constituent material of the positive electrode lead-out portion may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt and rare earth elements, and may also include elements as impurities.

[0186] To facilitate installation of the positive lead-out portion 50 , the positive lead-out portion 50 is fixed to the side of the top cover 22 of the outer shell 20 away from the electrode assembly 10 , and the positive electrode adapter 60 is formed into a protrusion passing through the through hole on the top cover 22 for welding to the positive lead-out portion 50 .

[0187] Figure 13 is an exploded schematic diagram of other embodiments of batteries according to the present disclosure. Figure 14 is a schematic diagram of the connection of multiple battery cells according to other embodiments of batteries according to the present disclosure. Figure 15 is a schematic diagram of the structure of other embodiments of battery cells according to the present disclosure. Referring to Figures 13-15, in some embodiments, the aforementioned battery cell embodiments are also applicable to cylindrical battery cells 71.

[0188] In Figure 13, battery 70 includes a battery box and multiple battery cells 72 housed within it. The battery box provides storage, support, cooling, sealing, and impact protection for the battery cells 72. It also prevents external liquids or other foreign matter from adversely affecting the charging, discharging, or safety of the battery cells. The battery box may include a body 73 and a cover 74 that engages with the body 73.

[0189] In Figure 14 , individual battery cells 71 can be electrically connected via busbars 72 , such as in series, parallel, or hybrid configurations, to achieve the desired electrical performance parameters of battery 70. Multiple battery cells 71 are arranged in rows, and one or more rows of battery cells 71 can be placed within the housing as needed. Alternatively, one or more layers of battery cells 71 can be arranged along the height of battery 70 as needed.

[0190] FIG16 is a schematic diagram of an exploded view of the embodiment shown in FIG15 . FIG17 is a schematic diagram of a cross section of the embodiment shown in FIG15 . Referring to FIG15 to FIG17 , the housing 20 may include a cylindrical housing 21 and an open-ended top cover 22 located at one end of the housing 21. The positive lead-out portion 50 is provided on the top cover 22. The positive lead-out portion 50 may be a split structure, comprising a positive internal connection portion 51 located inside the housing 21 and partially extending from a through hole on the top cover 22, and a positive external connection portion 52 located outside the housing 21 and fixedly connected to the positive internal connection portion 51. The positive internal connection portion 51 may be welded to the positive current collector 111 of the electrode assembly 10 via the positive adapter 60.

[0191] The negative electrode lead-out portion 30 can be an integrally formed structure or a split structure. For example, the housing 21 can be welded to the negative electrode current collector 121 of the electrode assembly 10 via the negative electrode adapter 40 as the integrally formed negative electrode lead-out portion 30. Another example is that the negative electrode lead-out portion 30 can include the housing 21 and the top cover 22 electrically connected thereto, assembled together. Accordingly, the housing 21 serves as the negative electrode internal connection portion of the negative electrode lead-out portion 30, and the top cover 22 serves as the negative electrode external connection portion of the negative electrode lead-out portion 30 and is insulated and isolated from the positive electrode lead-out portion 50.

[0192] In other embodiments, the negative electrode lead-out portion 30 may be disposed on the top cover 22, with the housing 21 serving as the integrally formed positive electrode lead-out portion 50, or the housing 21 and the top cover 22 electrically connected thereto may serve as the positive electrode internal connection portion and the positive electrode external connection portion of the separate positive electrode lead-out portion 50, respectively. In still other embodiments, both the positive electrode lead-out portion 50 and the negative electrode lead-out portion 30 may be disposed on the top cover 22.

[0193] Figure 18 is a schematic structural diagram of further embodiments of battery cells according to the present disclosure. Figure 19 is an exploded schematic diagram of the embodiment shown in Figure 18. Figure 20 is a cross-sectional schematic diagram of the embodiment shown in Figure 18. Figures 18-20 show another embodiment of a cylindrical battery cell.

[0194] 18-20 , in some embodiments, the outer shell 20 includes a shell body 21 and a top cover 22 , wherein one end of the shell body 21 has an end opening, and the top cover 22 covers and is fixed to the end opening; wherein the top cover 22 serves as the positive electrode lead-out portion 50 to be electrically connected to the positive electrode current collector 111 , and is used to be connected to the conductor outside the battery cell 71 ; the shell wall of the shell body 21 serves as the negative electrode lead-out portion 30 to be electrically connected to the metal base 121 b , and is used to be connected to the conductor outside the battery cell 71 .

[0195] For the negative electrode lead-out portion of the integrally molded structure, the shell wall is used as the negative electrode lead-out portion to electrically connect to the metal substrate and the external conductor. This allows the negative electrode lead-out portion to obtain a larger electrical connection area, which can reduce internal resistance. It also has a simpler structure, takes up less space, and is conducive to further improving the battery capacity. Using the top cover as the positive electrode lead-out portion to connect the positive electrode current collector and the external conductor allows the positive electrode lead-out portion to obtain a larger electrical connection area, reduces internal resistance, and facilitates connection to the external conductor.

[0196] FIG21 is an exploded schematic diagram of another embodiment with reference to FIG19 . Referring to FIG21 , compared with the embodiment shown in FIG19 , the housing 20 includes a shell 21 and a top cover 22. One end of the shell 21 has an end opening, and the top cover 22 covers and is fixed to the end opening. The top cover 22 serves as the negative electrode lead-out portion 30 and is electrically connected to the metal substrate 121b, and is used to connect to the conductor outside the battery cell 71; the shell wall of the shell 21 serves as the positive electrode lead-out portion 50 and is electrically connected to the positive electrode current collector 111, and is used to connect to the conductor outside the battery cell 71.

[0197] For the negative electrode lead-out portion of the integrally molded structure, using the top cover as the negative electrode lead-out portion to electrically connect to the metal substrate and the external conductor can provide a larger electrical connection area for the negative electrode lead-out portion, reduce internal resistance, and be more simple in structure, occupying less space, which is conducive to further improving the battery capacity. Using the shell wall as the positive electrode lead-out portion to connect the positive electrode current collector and the external conductor can also provide a larger electrical connection area for the positive electrode lead-out portion, reduce internal resistance, and facilitate connection to the external conductor.

[0198] Figure 22 is a schematic structural diagram of further embodiments of battery cells according to the present disclosure. Figure 23 is an exploded schematic diagram of the embodiment shown in Figure 22. Figure 24 is a cross-sectional schematic diagram of the embodiment shown in Figure 22. Figures 22-24 show yet another embodiment of a cylindrical battery cell.

[0199] Referring to Figures 22-24, in some embodiments, the outer shell 20 includes a housing 21, a first top cover 22a, and a second top cover 22b. The housing 21 has openings at opposite ends, and the first top cover 22a and the second top cover 22b respectively cover and are fixed to the openings at opposite ends of the housing 21. The second top cover 22b serves as the negative electrode lead-out portion 30, electrically connected to the metal substrate 121b, and is used to connect to a conductor external to the battery cell 71. The first top cover 22a serves as the positive electrode lead-out portion 50, electrically connected to the positive electrode current collector 111, and is used to connect to a conductor external to the battery cell 71.

[0200] For the negative electrode lead-out portion of the integrally molded structure, using the second top cover as the negative electrode lead-out portion to electrically connect to the metal substrate and the external conductor can provide a larger electrical connection area for the negative electrode lead-out portion, reduce internal resistance, and be more simple in structure, occupying less space, which is conducive to further improving battery power. Using the first top cover as the positive electrode lead-out portion to connect the positive electrode current collector and the external conductor can also provide a larger electrical connection area for the positive electrode lead-out portion, reduce internal resistance, and facilitate connection to the external conductor.

[0201] Figure 25 is an exploded schematic diagram of another embodiment with reference to Figure 23. Referring to Figure 25, compared to the embodiment shown in Figure 23, the outer casing 20 includes a shell 21, a first top cover 22a, and a second top cover 22b. The shell 21 has openings at opposite ends, and the first top cover 22a and the second top cover 22b respectively cover and are fixed to the openings at opposite ends of the shell 21. The first top cover 22a serves as the negative electrode lead-out portion 30, electrically connected to the metal substrate 121b, and is used to connect to a conductor external to the battery cell 71. The second top cover 22b serves as the positive electrode lead-out portion 50, electrically connected to the positive electrode current collector 111, and is used to connect to a conductor external to the battery cell 71.

[0202] For the negative electrode lead-out portion of the integrally molded structure, the first top cover is used as the negative electrode lead-out portion to electrically connect to the metal substrate and the external conductor. This allows the negative electrode lead-out portion to have a larger electrical connection area, reduces internal resistance, and is structurally simpler, taking up less space, which helps further increase battery power. The second top cover is used as the positive electrode lead-out portion to connect the positive electrode current collector and the external conductor. This allows the positive electrode lead-out portion to have a larger electrical connection area, reduces internal resistance, and facilitates connection to the external conductor.

[0203] In one aspect of the present disclosure, a battery 70 is provided, comprising the battery cell 71 according to any one of the aforementioned embodiments.

[0204] A battery using the aforementioned battery cells can reduce weight and cost.

[0205] 2 , 3 , 13 and 14 , in some embodiments, the battery 70 includes a plurality of battery cells 71 and further includes a busbar 72 for electrically connecting the plurality of battery cells 71 , wherein the constituent material of the busbar 72 includes an aluminum element having a greater mass percentage than other elements.

[0206] In this embodiment, the elements other than aluminum in the constituent material of the busbar 72 may include one or more of copper, manganese, silicon, magnesium, zinc, nickel, iron, titanium, chromium, zirconium, cobalt and rare earth elements, and may also include elements as impurities.

[0207] The plurality of battery cells 71 are electrically connected using a busbar 72 composed of a material comprising aluminum in a higher mass percentage than other elements. This allows for easier and more reliable welding of the busbar 72 to the negative electrode lead 30, which also comprises aluminum in a higher mass percentage than other elements. The busbar 72 serves as an external conductor to the battery cells 71, electrically connecting to at least one of the negative electrode lead and the positive electrode lead of the battery cells 71.

[0208] In some embodiments, the material constituting the current collector 72 includes aluminum in an amount greater than or equal to 90% by mass.

[0209] The material constituting the busbar 72 is an aluminum alloy material or a pure aluminum material containing aluminum elements in an amount greater than or equal to 90% by mass, which can more easily achieve a reliable connection effect during connection processes such as welding.

[0210] In one aspect of the present disclosure, an electric device is provided, comprising the battery 70 according to any one of the aforementioned embodiments.

[0211] The electric device using the above-mentioned battery can reduce weight and cost.

[0212] In some specific embodiments, as shown in Figures 4-8 and 10, a battery cell 71 includes an electrode assembly 10, a square box-shaped housing 20, a negative electrode lead-out portion 30, a negative electrode adapter 40, a positive electrode lead-out portion 50, and a positive electrode adapter 60. The electrode assembly 10 includes a positive electrode sheet 11 and a negative electrode sheet 12. The positive electrode sheet 11 includes a positive electrode current collector 111 and a positive electrode active material 112 disposed on the positive electrode current collector 111. The negative electrode sheet 12 includes a negative electrode current collector 121 and a negative electrode active material 122 disposed on the negative electrode current collector 121. The positive electrode active material 112 includes at least one of a sodium-containing layered transition metal oxide, a sodium-containing phosphate, and a Prussian blue analog. The negative electrode current collector 121 is composed of the metal substrate 121b, and the positive electrode current collector 111 is a metal current collector.

[0213] The outer casing 20 includes a shell 21 and a top cover 22 mounted on the open end of the shell 21. Both the negative electrode lead 30 and the positive electrode lead 50 are mounted on the top cover 22. One end of the negative electrode adapter 40 is welded to the negative electrode lead 30 and the other end is welded to the negative electrode current collector 121. One end of the positive electrode adapter 60 is welded to the positive electrode lead 50 and the other end is welded to the positive electrode current collector 111.

[0214] The negative electrode lead-out portion 30 is a split structure, comprising a negative electrode internal connection portion 31 located inside the top cover 22, and a negative electrode external connection portion 32 connected to the negative electrode internal connection portion 31 and located outside the top cover 22. The positive electrode lead-out portion 50 is a split structure, comprising a positive electrode internal connection portion 51 located inside the top cover 22, and a positive electrode external connection portion 52 connected to the positive electrode internal connection portion 51 and located outside the top cover 22.

[0215] The negative electrode internal connection 31, negative electrode external connection 32, negative electrode adapter 40, positive electrode internal connection 51, positive electrode external connection 52, and positive electrode adapter 60 are all constructed from aluminum alloy materials containing 90% or more of aluminum by mass, or pure aluminum. The metal base 121b of the negative electrode current collector 121 and the positive electrode current collector 111 are both constructed from pure aluminum materials containing 99% or more of aluminum by mass. The current busbar 72 used to connect the battery cells 71 is also constructed from aluminum alloy materials containing 90% or more of aluminum by mass, or pure aluminum.

[0216] In some specific embodiments, as shown in Figures 8, 10, and 18-20, a battery cell 71 includes an electrode assembly 10, a cylindrical housing 20, a negative electrode lead-out portion 30, a negative electrode adapter 40, a positive electrode lead-out portion 50, and a positive electrode adapter 60. The electrode assembly 10 includes a positive electrode sheet 11 and a negative electrode sheet 12. The positive electrode sheet 11 includes a positive electrode current collector 111 and a positive electrode active material 112 disposed on the positive electrode current collector 111. The negative electrode sheet 12 includes a negative electrode current collector 121 and a negative electrode active material 122 disposed on the negative electrode current collector 121. The positive electrode active material 112 includes at least one of a sodium-containing layered transition metal oxide, a sodium-containing phosphate, and a Prussian blue analog. The negative electrode current collector 121 is composed of the metal substrate 121b, and the positive electrode current collector 111 is a metal current collector.

[0217] The outer casing 20 includes a housing 21, which serves as the negative electrode lead-out portion 30, and a top cover 22, which is located on the open end of the housing 21 and serves as the positive electrode lead-out portion 50. The top cover 22 is insulated from the housing 21 by an insulating member. One end of the negative electrode adapter 40 is welded to the negative electrode current collector 121, and the other end is welded to the bottom of the housing 21. One end of the positive electrode adapter 60 is welded to the top cover 22, and the other end is welded to the positive electrode current collector 111.

[0218] The housing 21, negative electrode adapter 40, top cover 22, and positive electrode adapter 60 are all constructed from aluminum alloys or pure aluminum containing 90% or greater aluminum by mass. The metal base 121b of the negative electrode current collector 121 and the positive electrode current collector 111 are both constructed from pure aluminum containing 99% or greater aluminum by mass. The current busbar 72, used to connect the battery cells 71, is also constructed from aluminum alloys or pure aluminum containing 90% or greater aluminum by mass.

[0219] In some specific embodiments, as shown in Figures 9, 11, and 22-24, a battery cell 71 includes an electrode assembly 10, a cylindrical housing 20, a negative electrode lead 30, a negative electrode adapter 40, a positive electrode lead 50, and a positive electrode adapter 60. The electrode assembly 10 includes a positive electrode sheet 11 and a negative electrode sheet 12. The positive electrode sheet 11 includes a positive electrode current collector 111 and a positive electrode active material 112 disposed on the positive electrode current collector 111. The negative electrode sheet 12 includes a negative electrode current collector 121 and a negative electrode active material 122 disposed on the negative electrode current collector 121. The positive electrode active material 112 includes at least one of a sodium-containing layered transition metal oxide, a sodium-containing phosphate, and a Prussian blue analog.

[0220] The negative electrode current collector 121 includes a metal substrate 121b and a first insulating material layer 121i, with the metal substrate 121b disposed on both sides of the first insulating material layer 121i along the thickness direction. The positive electrode current collector 111 includes a second insulating material layer 111i and a conductive layer 111c located on both sides of the second insulating material layer 111i along the thickness direction.

[0221] The outer casing 20 includes a housing 21 and a first cover 22a and a second cover 22b, which are mounted on the openings at both ends of the housing 21 and serve as the positive electrode lead-out portion 50 and the negative electrode lead-out portion 30, respectively. The first cover 22a and the second cover 22b are insulated from the housing 21 by insulating members. The negative electrode adapter 40 is welded to the negative electrode current collector 121 at one end and to the second cover 22b at the other end. The positive electrode adapter 60 is welded to the first cover 22a at one end and to the positive electrode current collector 111 at the other end.

[0222] The second top cover 22b, negative electrode adapter 40, first top cover 22a, and positive electrode adapter 60 are all constructed from aluminum alloys containing 90% or greater aluminum by mass or pure aluminum. The metal base 121b of the negative electrode current collector 121 and the conductive layer 111c of the positive electrode current collector 111 are both constructed from pure aluminum containing 99% or greater aluminum by mass. The current busbar 72 used to connect the battery cells 71 is also constructed from aluminum alloys containing 90% or greater aluminum by mass or pure aluminum.

[0223] While the present disclosure has been described with reference to preferred embodiments, various modifications may be made thereto and equivalent components may be substituted without departing from the scope of the present disclosure. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present disclosure is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell (71), comprising: An electrode assembly (10) comprises a positive electrode sheet (11) and a negative electrode sheet (12), wherein the positive electrode sheet (11) comprises a positive electrode current collector (111) and a positive electrode active material (112) disposed on the positive electrode current collector (111), wherein the positive electrode active material (112) comprises an active material capable of reversibly extracting and embedding sodium ions, and the negative electrode sheet (12) comprises a negative electrode current collector (121), wherein the negative electrode current collector (121) comprises a metal matrix (121b); The constituent material of the metal matrix (121b) includes aluminum element, and the mass percentage of the aluminum element is greater than the mass percentage of other elements.

2. The battery cell (71) according to claim 1, further comprising: A housing (20) having a chamber for accommodating the electrode assembly (10); A negative electrode lead-out portion (30) is arranged on the housing (20), and the negative electrode lead-out portion (30) is used to electrically connect the metal substrate (121b) and a conductor outside the battery cell (71).

3. The battery cell (71) according to claim 2, wherein: The negative electrode lead-out portion (30) is an integrally formed structure, and the constituent material of the negative electrode lead-out portion (30) comprises an aluminum element, wherein the mass percentage of the aluminum element is greater than the mass percentage of other elements.

4. The battery cell (71) according to claim 3, wherein: The constituent material of the metal substrate (121b) and the constituent material of the negative electrode lead-out portion (30) both contain aluminum elements with a mass percentage greater than or equal to 90%.

5. The battery cell (71) according to claim 2, wherein: The negative electrode lead-out portion (30) is a split structure, and includes a fixedly connected negative electrode internal connection portion (31) and a negative electrode external connection portion (32), wherein the negative electrode internal connection portion (31) is electrically connected to the metal substrate (121b), and the negative electrode external connection portion (32) is used to connect to a conductor outside the battery cell (71), and the constituent materials of the negative electrode internal connection portion (31) and the negative electrode external connection portion (32) both include aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

6. The battery cell (71) according to claim 5, wherein: The constituent material of the metal substrate (121b), the constituent material of the negative electrode internal connection part (31) and the constituent material of the negative electrode external connection part (32) all contain aluminum elements with a mass percentage greater than or equal to 90%.

7. The battery cell (71) according to any one of claims 2 to 6, further comprising: A negative electrode adapter (40) electrically connecting the metal substrate (121b) and the negative electrode lead-out portion; The constituent material of the negative electrode adapter (40) includes aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

8. The battery cell (71) according to claim 7, wherein: The constituent material of the negative electrode adapter (40) includes aluminum elements with a mass percentage greater than or equal to 90%.

9. The battery cell (71) according to any one of claims 1 to 8, wherein: The negative electrode current collector (121) is composed of the metal matrix (121b), and the constituent material of the metal matrix (121b) includes aluminum elements with a mass percentage greater than or equal to 99%.

10. The battery cell (71) according to any one of claims 1 to 8, wherein: The negative electrode current collector (121) further comprises a first insulating material layer (121i), and the metal substrate (121b) is respectively arranged on both sides of the first insulating material layer (121i) in the thickness direction, and the constituent material of the metal substrate (121b) comprises aluminum elements with a mass percentage greater than or equal to 99%.

11. The battery cell (71) according to any one of claims 1 to 10, further comprising: A housing (20) having a chamber for accommodating the electrode assembly (10); A positive electrode lead-out portion (50) is disposed on the housing (20) and is used to electrically connect the positive electrode current collector (111) and a conductor outside the battery cell (71); The constituent material of the positive electrode lead-out portion (50) includes aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

12. The battery cell (71) according to claim 11, wherein: The constituent material of the positive electrode lead-out portion (50) includes aluminum elements with a mass percentage greater than or equal to 90%.

13. The battery cell (71) according to any one of claims 11 to 12, further comprising: A positive electrode adapter (60) is electrically connected to the positive electrode lead-out portion (50) and the positive electrode current collector (111) respectively; The constituent material of the positive electrode adapter (60) includes aluminum, and the mass percentage of the aluminum is greater than the mass percentage of other elements.

14. The battery cell (71) according to claim 13, wherein: The constituent material of the positive electrode adapter (60) includes aluminum elements with a mass percentage greater than or equal to 90%.

15. The battery cell (71) according to any one of claims 11 to 14, wherein: The positive electrode current collector (111) is a metal current collector, and the constituent material of the metal current collector includes aluminum elements with a mass percentage greater than or equal to 99%.

16. The battery cell (71) according to any one of claims 11 to 14, wherein: The positive electrode current collector (111) comprises: a second insulating material layer (111i) and a conductive layer (111c) located on both sides of the second insulating material layer (111i) in the thickness direction of the second insulating material layer (111i), and the constituent material of the conductive layer (111c) comprises aluminum elements with a mass percentage greater than or equal to 99%.

17. The battery cell (71) according to any one of claims 3 to 4, wherein: The housing (20) comprises a shell (21) and a top cover (22); one end of the shell (21) has an end opening, and the top cover (22) covers and is fixed to the end opening; The top cover (22) is electrically connected to the metal substrate (121b) as the negative electrode lead-out portion (30), and is used to connect to a conductor outside the battery cell (71); the shell wall of the shell (21) is electrically connected to the positive electrode current collector (111) as the positive electrode lead-out portion (50), and is used to connect to a conductor outside the battery cell (71); or The top cover (22) serves as the positive electrode lead-out portion (50) and is electrically connected to the positive electrode current collector (111), and is used to connect to a conductor outside the battery cell (71); the shell wall of the shell (21) serves as the negative electrode lead-out portion (30) and is electrically connected to the metal substrate (121b), and is used to connect to a conductor outside the battery cell (71).

18. The battery cell (71) according to any one of claims 3 to 4, wherein: The housing (20) comprises a shell (21), a first top cover (22a) and a second top cover (22b), the shell (21) having end openings at opposite ends, and the first top cover (22a) and the second top cover (22b) respectively cover and are fixed to the end openings at opposite ends of the shell (21); wherein the first top cover (22a) is electrically connected to the metal substrate (121b) as the negative electrode lead-out portion (30) and is used to connect to a conductor outside the battery cell (71); the second top cover (22b) is electrically connected to the positive electrode current collector (111) as the positive electrode lead-out portion (50) and is used to connect to a conductor outside the battery cell (71); or The second top cover (22b) is electrically connected to the metal substrate (121b) as the negative electrode lead-out portion (30), and is used to connect to a conductor outside the battery cell (71); the first top cover (22a) is electrically connected to the positive electrode current collector (111) as the positive electrode lead-out portion (50), and is used to connect to a conductor outside the battery cell (71).

19. The battery cell (71) according to any one of claims 1 to 18, wherein: The positive electrode active material (112) includes at least one of a sodium-containing layered transition metal oxide, a sodium-containing phosphate, and a Prussian blue analog.

20. A battery (70), comprising: A battery cell (71) according to any one of claims 1 to 19.

21. The battery (70) according to claim 20, wherein: The battery (70) includes a plurality of battery cells (71) and a busbar (72) for electrically connecting the plurality of battery cells (71). The constituent material of the busbar (72) includes an aluminum element whose mass percentage is greater than that of other elements.

22. The battery (70) according to claim 21, wherein: The material constituting the current collector (72) includes aluminum elements with a mass percentage greater than or equal to 90%.

23. An electrical device, comprising: A battery (70) according to any one of claims 20 to 22.

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