Battery monomer, battery, power utilization device and energy storage device

Abstract

The invention discloses a battery monomer, a battery, a power utilization device and an energy storage device. The battery monomer comprises a shell and at least one electrode assembly, the electrode assembly is accommodated in the shell, the shell is a straight parallelepiped, the size of the shell in the first direction is W1, the size of the shell in the second direction is T1, the size of the shell in the third direction is H1, and the first direction, the second direction and the third direction are perpendicular to one another; the shell comprises a first wall, a second wall, a third wall, a fourth wall, a fifth wall and a sixth wall, the first wall and the second wall are oppositely arranged in the first direction, the third wall and the fourth wall are oppositely arranged in the second direction, the fifth wall and the sixth wall are oppositely arranged in the third direction, the thickness sum of the first wall and the second wall is a, the thickness sum of the third wall and the fourth wall is b, the thickness sum of the fifth wall and the sixth wall is c, and (W1-a) * (T1-b) * (H1-c) / (W1 * T1 * H1) is larger than or equal to 90%. Therefore, under the same chemical material system, the volume energy density of the battery monomer can be improved.

Description

Battery cells, batteries, electrical devices and energy storage devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the international application entitled “Battery Cell, Battery, Electrical Device and Energy Storage Device” (PCT / CN2023 / 101943) filed on June 21, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, an electrical device, and an energy storage device. Background Art

[0004] With the development of new energy technologies, batteries are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, energy storage devices, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0005] In the development of battery technology, how to improve the volume energy density of battery cells is an urgent problem to be solved in battery technology.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a battery cell, a battery, an electrical device, and an energy storage device, which can effectively improve the volume energy density of the battery cell.

[0008] In a first aspect, an embodiment of the present application provides a battery cell, comprising: a shell, the shell being a right parallelepiped, the size of the shell in a first direction being W1, the size of the shell in a second direction being T1, and the size of the shell in a third direction being H1, the first direction, the second direction and the third direction being perpendicular to each other; at least one electrode assembly, the electrode assembly being accommodated in the shell; the shell comprising a first wall and a second wall arranged opposite to each other along the first direction, a third wall and a fourth wall arranged opposite to each other along the second direction, and a fifth wall and a sixth wall arranged opposite to each other along the third direction, the sum of the thicknesses of the first wall and the second wall being a, the sum of the thicknesses of the third wall and the fourth wall being b, and the sum of the thicknesses of the fifth wall and the sixth wall being c, satisfying: (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥90%.

[0009] In the above technical solution, the ratio of the capacity of the battery cell shell to the volume of the shell is set to more than 90%, so that the internal space of the shell becomes larger, and the shell can accommodate a larger electrode assembly and more electrolyte. Under the same chemical material system, the volume energy density of the battery cell can be improved.

[0010] In some embodiments, (W1-a) / W1≥97.0%, (T1-b) / T1≥96.5%, and (H1-c) / H1≥96.5%. This can increase the proportion of the internal space of the housing in three dimensions, further increasing the volume energy density of the battery cell.

[0011] In some embodiments, the shell includes the first wall, the second wall, the third wall, the fourth wall and the fifth wall that are integrally formed, and the end cover is the sixth wall.

[0012] In some embodiments, the battery cell further includes a first insulating member and a second insulating member. The first insulating member is disposed between the fifth wall and the electrode assembly and abuts the fifth wall. The second insulating member is disposed between the sixth wall and the electrode assembly and abuts the sixth wall. The first insulating member has a maximum dimension d1 in the third direction, and the second insulating member has a maximum dimension d2 in the third direction, satisfying the following conditions: (W1-a-1.6mm)*(T1-b-1.6mm)*(H1-c-d1-d2) / (W1*T1*H1)≥88%, 0.3mm≤d1≤1.2mm, and 2mm≤d2≤10mm. This increases the space inside the housing for the electrode assembly, allowing for the placement of a larger electrode assembly, thereby further improving the volumetric energy density of the battery cell.

[0013] In some embodiments, the battery cell further includes a first insulating member and a second insulating member, the first insulating member is arranged between the fifth wall and the electrode assembly, and abuts the fifth wall; the second insulating member is arranged between the sixth wall and the electrode assembly, and abuts the sixth wall; the maximum dimension of the first insulating member in the third direction is d1, and the maximum dimension of the second insulating member in the third direction is d2, satisfying: (W1-a-4mm)*(T1-b-4mm)*(H1-c-d1-d2) / (W1*T1*H1)≥85%, 0.3mm≤d1≤1.2mm, and 2mm≤d2≤10mm.

[0014] In some embodiments, the outer shell includes a shell and two end covers, the shell has two openings arranged opposite to each other along the third direction, and the two end covers respectively cover the openings on the corresponding sides; the shell includes the first wall, the second wall, the third wall and the fourth wall formed in one piece, and the two end covers are the fifth wall and the sixth wall respectively.

[0015] In some embodiments, the battery cell further includes a third insulating member and a fourth insulating member, the third insulating member is arranged between the fifth wall and the electrode assembly, and abuts against the fifth wall; the fourth insulating member is arranged between the sixth wall and the electrode assembly, and abuts against the sixth wall; the maximum dimension of the third insulating member in the third direction is d3, and the maximum dimension of the fourth insulating member in the third direction is d4, satisfying: (W1-a-1.6mm)*(T1-b-1.6mm)*(H1-c-d3-d4) / (W1*T1*H1)≥88%, 2mm≤d3≤10mm, and 2mm≤d4≤10mm.

[0016] In some embodiments, the battery cell further includes a third insulating member and a fourth insulating member, the third insulating member is arranged between the fifth wall and the electrode assembly and abuts against the fifth wall; the fourth insulating member is arranged between the sixth wall and the electrode assembly and abuts against the sixth wall; the maximum dimension of the third insulating member in the third direction is d3, and the maximum dimension of the fourth insulating member in the third direction is d4, satisfying: (W1-a-4mm)*(T1-b-4mm)*(H1-c-d3-d4) / (W1*T1*H1)≥85%, 2mm≤d3≤10mm, and 2mm≤d4≤10mm.

[0017] In some embodiments, 3000 cm 3 ≤W1*T1*H1≤40000cm 3 This allows, on the one hand, the shell wall thickness to be kept within a reasonable range while maintaining a ratio of the shell's volume to its volume above 90%, thereby meeting the requirements for the shell's structural strength and rigidity. On the other hand, it allows the capacity and current of the battery cells to be controlled within an appropriate range, reducing the heat generated by the battery cells and the risk of damage to components in the circuit.

[0018] In some embodiments, 3200 cm 3 ≤W1*T1*H1≤32000cm 3 .

[0019] In some embodiments, 3720 cm 3 ≤W1*T1*H1≤12500cm 3 .

[0020] In some embodiments, 4000 cm 3 ≤W1*T1*H1≤6000cm 3 .

[0021] In some embodiments, the electrode assembly includes a body and a tab extending from the body. The body is flat, and the maximum dimension of the body in the first direction is W2, the maximum dimension of the body in the second direction is T2, and the maximum dimension of the body in the third direction is H2, satisfying the following: (W2*T2*H2) / (W1*T1*H1)≥80%. In this way, the electrode assembly can fully utilize the internal space of the housing, avoiding the situation where the housing has a large volume and the electrode assembly has a small volume, thereby improving the volumetric energy density of the battery cell and reducing the movement of the electrode assembly within the housing.

[0022] In some embodiments, W2 / (W1-a)≥91.5%, T2 / (T1-b)≥93.2%, and H2 / (H1-c)≥94.0%.

[0023] In some embodiments, the electrode assembly has a wound structure, the main body comprising a straight region, a first bending region, and a second bending region, with the first bending region and the second bending region respectively located at opposite ends of the straight region along the first direction. The first bending region comprises a plurality of stacked first bending portions, with the distance between the innermost vertex of the first bending portion and the outer vertex of the outermost first bending portion of the plurality of first bending portions along the first direction being W3. The second bending region comprises a plurality of stacked second bending portions, with the distance between the innermost vertex of the second bending portion and the outer vertex of the outermost second bending portion of the plurality of second bending portions along the first direction being W4. The following condition is satisfied: (W3+W4) / W2≤30%. Thus, the proportion of the dimensions of the first and second bending regions in the first direction is reduced, while the proportion of the dimensions of the straight region in the first direction is increased, thereby reducing the volumetric proportion of the gap between the bending region and the inner surface of the outer shell, thereby improving the effective utilization of the internal space of the outer shell and increasing the volumetric energy density of the battery cell.

[0024] In some embodiments, the first wall, the second wall, the third wall, the fourth wall, the fifth wall, and the sixth wall are all made of an aluminum alloy, wherein the aluminum alloy comprises the following components by mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual elements ≤ 0.05%, and other elements in total ≤ 0.15%. This results in a stronger aluminum alloy, which, when used as the outer shell material, can significantly enhance the outer shell's ability to resist impact and improve the reliability of the battery cell.

[0025] In some embodiments, the outer shell includes a shell and an end cover, the shell has an opening, the end cover covers the opening, and the end cover is welded to the shell; the shell includes the first wall, the second wall, the third wall, the fourth wall and the fifth wall formed in one piece, and the end cover is the sixth wall; the thickness of the first wall and the second wall is a1, the thickness of the third wall and the fourth wall is b1, the thickness of the fifth wall is c1, and the thickness of the sixth wall is c2, satisfying: c2>c1, c1>a1, c1>b1.

[0026] In some embodiments, 0.5 mm ≤ a1 ≤ 1.5 mm, 0.5 ≤ b1 ≤ 1.5 mm, 1.0 mm ≤ c1 ≤ 2.5 mm, and 1.5 mm ≤ c2 ≤ 4 mm.

[0027] In some embodiments, the battery cell includes an electrode terminal, the electrode terminal is disposed on the end cover or the fifth wall, and the electrode terminal is electrically connected to the electrode assembly.

[0028] In some embodiments, (W1-2*a1)*(T1-2*b1)*(H1-c1-c2) / (W1*T1*H1)≥95%.

[0029] In some embodiments, the shell includes a shell and two end covers, the shell has two openings arranged opposite to each other along the third direction, the two end covers respectively cover the openings on the corresponding sides, and the end covers are welded to the shell; the shell includes the first wall, the second wall, the third wall and the fourth wall formed as one piece, and the two end covers are the fifth wall and the sixth wall respectively; the thickness of the first wall and the second wall is a1, the thickness of the third wall and the fourth wall is b1, the thickness of the fifth wall is c1, and the thickness of the sixth wall is c2, satisfying: c2=c1, c1>a1, c1>b1.

[0030] In some embodiments, 0.5 mm ≤ a1 ≤ 1.5 mm, 0.5 ≤ b1 ≤ 1.5 mm, and 1.5 mm ≤ c2 ≤ 4 mm.

[0031] In some embodiments, the battery cell includes an electrode terminal, the electrode terminal is disposed on the end cap, and the electrode terminal is electrically connected to the electrode assembly.

[0032] In some embodiments, (W1-2*a1)*(T1-2*b1)*(H1-2*c1) / (W1*T1*H1)≥95%.

[0033] In some embodiments, T1<W1, T1

[0034] In some embodiments, 40 mm ≤ T1 ≤ 150 mm.

[0035] In some embodiments, the third direction is parallel to the direction of gravity, the battery cell includes an electrolyte, and 120 mm ≤ H1 ≤ 400 mm.

[0036] In some embodiments, 150 mm ≤ W1 ≤ 1500 mm.

[0037] In some embodiments, the positive electrode material of the battery cell includes lithium-containing phosphate, and the capacity of the battery cell is C, which satisfies: C≥350Ah, C / ((W1-a)*(T1-b)*(H1-c))≥118Ah / L.

[0038] In some embodiments, the positive electrode material of the battery cell includes a lithium transition metal oxide, and the capacity of the battery cell is C, satisfying: C≥650Ah, C / ((W1-a)*(T1-b)*(H1-c))≥190Ah / L.

[0039] In some embodiments, the battery cell is a sodium ion battery, and the capacity of the battery cell is C, satisfying: C≥260Ah, C / ((W1-a)*(T1-b)*(H1-c))≥87Ah / L.

[0040] In a second aspect, an embodiment of the present application provides a battery, comprising a battery case and a battery cell provided by any one embodiment of the first aspect, wherein the battery cell is housed in the battery case.

[0041] In a third aspect, an embodiment of the present application provides an electrical device, comprising the battery provided in any one embodiment of the second aspect.

[0042] In a fourth aspect, an embodiment of the present application provides an energy storage device, comprising an energy storage box and a plurality of battery cells provided by any one embodiment of the first aspect, wherein the energy storage box comprises a battery compartment, and the plurality of battery cells are accommodated in the battery compartment. ​

[0043] In some embodiments, the battery cells include electrode terminals, which are disposed on the housing. The sum of the volumes of the housings of the multiple battery cells is V1, and the volume of the battery compartment is V2, satisfying the following relationship: 0.5 ≤ V1 / V2 ≤ 0.95. This improves the space utilization of the energy storage device, allowing more battery cells to be arranged within the battery compartment of the energy storage box, i.e., more energy-supplying structures to be arranged within a unit space. This increases energy density and thus capacity without increasing the occupied space. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without any creative work.

[0045] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0046] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0047] FIG3 is a schematic structural diagram of an energy storage device provided in some embodiments of the present application;

[0048] FIG4 is a schematic diagram of the internal structure of the energy storage device shown in FIG3 ;

[0049] FIG5 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0050] FIG6 is an exploded view of the battery cell shown in FIG5 ;

[0051] FIG7 is a cross-sectional exploded view of the battery cell shown in FIG5 taken along the XZ plane;

[0052] FIG8 is a cross-sectional exploded view of the battery cell shown in FIG5 taken along the YZ plane;

[0053] FIG9 is a schematic structural diagram of a battery cell provided in some other embodiments of the present application;

[0054] FIG10 is an exploded view of the battery cell shown in FIG9 .

[0055] FIG11 is a cross-sectional exploded view of the battery cell shown in FIG10 taken along the XZ plane;

[0056] FIG12 is a cross-sectional exploded view of the battery cell shown in FIG10 taken along the YZ plane;

[0057] FIG13 is a front view of the electrode assembly shown in FIG6;

[0058] FIG14 is a side view of the electrode assembly shown in FIG6;

[0059] FIG15 is a top view of the electrode assembly shown in FIG6;

[0060] FIG16 is a cross-sectional view of the electrode assembly shown in FIG6 ;

[0061] FIG17 is an exploded view of a battery cell provided in some further embodiments of the present application;

[0062] FIG18 is a front view of the electrode assembly shown in FIG17;

[0063] FIG19 is a side view of the electrode assembly shown in FIG17.

[0064] Icons: 1-housing; 11-shell; 12-end cap; 101-first wall; 102-second wall; 103-third wall; 104-fourth wall, 105-fifth wall; 106-sixth wall; 121-positive electrode terminal; 122-negative electrode terminal; 141-first insulating member; 142-second insulating member; 143-third insulating member; 144-fourth insulating member; 2-electrode assembly; 21-body; 22-positive electrode ear; 23-negative electrode ear; 24-positive electrode sheet; 25-negative electrode sheet ;26-isolating membrane;10-battery cell;20-battery case;201-first part;202-second part;100-battery;200-controller;300-motor;400-energy storage case;401-battery compartment;402-electrical compartment;403-column;404-battery bracket;1000-vehicle;2000-energy storage device;A-straight area;B1-first bending area;B2-second bending area;X-first direction;Y-second direction;Z-third direction. DETAILED DESCRIPTION

[0065] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0066] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0067] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0068] In the embodiments of the present application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. "Multiple" in the present application refers to more than two (including two).

[0069] In the present application, the battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application are not limited to this.

[0070] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a battery case that encloses one or more battery cells. The battery case prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0071] A battery cell consists of a casing, an electrode assembly, and an electrolyte. The casing is used to house the electrode assembly and electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet comprises a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The uncoated positive electrode collector protrudes from the coated positive electrode collector, and the uncoated positive electrode collector serves as the positive tab. For lithium-ion batteries, for example, the positive electrode current collector can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet comprises a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The uncoated negative electrode collector protrudes from the coated negative electrode collector, and the uncoated negative electrode collector serves as the negative tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, among others. To ensure that high currents can pass without fusing, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene). Furthermore, the electrode assembly can be a wound or laminated structure, although the embodiments of the present application are not limited thereto.

[0072] Battery cells may also include electrode terminals, which are located on the outer casing and electrically connect to the tabs of the electrode assembly to output electrical energy from the battery cell. The electrode terminals and tabs may be directly connected, for example, by direct welding. They may also be indirectly connected, for example, through a current collecting member. The current collecting member may be a metal conductor, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0073] The development of battery technology requires simultaneous consideration of multiple design factors, such as safety, cycle life, discharge capacity, charge and discharge rate, and other performance parameters. Furthermore, volumetric energy density is also an important parameter for evaluating battery performance.

[0074] In order to improve safety and reduce the risk of shell rupture when the battery cell is subjected to external impact or when the internal pressure of the battery cell is high, the shell is usually designed to be thicker. However, a thicker shell will reduce the internal space of the shell. In addition, in order to reduce the possibility of internal short circuit in the battery cell, some insulating parts are usually set inside the shell. These insulating parts will inevitably take up a part of the space, leaving the space for the electrode assembly very limited, resulting in a low volume energy density of the battery cell. For larger volumes, especially those with a volume of 3000cm 3The above battery cells have large electrode assembly mass, which exerts a large impact on the casing and requires the casing to withstand a greater load. Therefore, the casing wall is usually designed to be thicker, which makes the problem of low volume energy density of large-volume battery cells more significant.

[0075] In view of this, an embodiment of the present application provides a battery cell, in which the ratio of the capacity of the shell to the volume of the shell is above 90%, thereby making the internal space of the shell larger to accommodate a larger electrode assembly and more electrolyte. Under the same chemical material system, the volume energy density of the battery cell can be improved.

[0076] The battery cells described in the embodiments of the present application are suitable for use in batteries and electrical devices using the batteries.

[0077] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0078] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0079] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery 100 is disposed within vehicle 1000. Battery 100 can be located at the bottom, front, or rear of vehicle 1000. Battery 100 can be used to power vehicle 1000, for example, as an operating power source for vehicle 1000.

[0080] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0081] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0082] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a battery cell 10 and a battery case 20, wherein the battery cell 10 is accommodated in the battery case 20.

[0083] The battery case 20 is a component that houses the battery cells 10 and provides a storage space for the battery cells 10. The battery case 20 can have various structures. In some embodiments, the battery case 20 can include a first portion 201 and a second portion 202, which overlap to define a storage space for the battery cells 10. The first portion 201 and the second portion 202 can have various shapes, such as a rectangular parallelepiped or a cylinder. The first portion 201 can be a hollow structure with one side open, and the second portion 202 can also be a hollow structure with one side open. The open side of the second portion 202 overlaps the open side of the first portion 201, forming the battery case 20 with a storage space. Alternatively, the first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a plate-like structure. The second portion 202 overlaps the open side of the first portion 201, forming the battery case 20 with a storage space. The first portion 201 and the second portion 202 can be sealed by a sealing element, which can be a sealing ring, sealant, etc.

[0084] In the battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 10. Multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection to form a battery module, which is then connected in series, parallel, or in a hybrid connection to form a whole and housed within the battery case 20. Alternatively, all battery cells 10 can be directly connected in series, parallel, or in a hybrid connection, and then the whole battery module 10 can be housed within the battery case 20.

[0085] In some embodiments, the battery 100 may further include a busbar (not shown) through which the multiple battery cells 10 can be electrically connected to each other, thereby enabling series connection, parallel connection, or hybrid connection of the multiple battery cells 10. The busbar may be a metal conductor, such as copper, iron, aluminum, stainless steel, or an aluminum alloy.

[0086] The battery cells described in the embodiments of the present application are also applicable to energy storage devices.

[0087] Energy storage devices are playing an increasingly prominent role in future energy applications. On the one hand, wind and solar power generation are intermittent and unstable in renewable energy generation. The introduction of energy storage devices can effectively suppress power fluctuations, thereby improving power quality. On the other hand, energy storage devices can also "shaving peaks and filling valleys," absorbing excess power during periods of low grid output power and then actively supplying power to the grid during peak output periods. This significantly reduces peak power, improves demand-side management capabilities, and promotes the use of renewable energy.

[0088] Please refer to FIG. 3 and FIG. 4 . FIG. 3 is a schematic diagram of the structure of the energy storage device 2000 provided in some embodiments of the present application. FIG. 4 is a schematic diagram of the internal structure of the energy storage device 2000 shown in FIG. 3 .

[0089] The energy storage device 2000 includes an energy storage housing 400, batteries 100, and a control module (not shown). The interior of the energy storage housing 400 is divided into a battery compartment 401 and an electrical compartment 402. The batteries 100 are placed in the battery compartment 401, and the control module is placed in the electrical compartment 402. The battery compartment 401 is provided with columns 403 and battery brackets 404. The columns 403 are generally arranged along the height of the energy storage housing 400. The battery brackets 404 are fixed to the columns 403, and the batteries 101 are placed on the battery brackets 404, so that multiple batteries 100 can be arranged in the battery compartment 401. Of course, in other embodiments, the battery cell 10 can also be placed directly in the battery compartment 401 without first placing the battery cell 10 in the battery case 20 and then placing the battery case 20 in the battery compartment 401. Therefore, there is no need to set the column 403 and the battery bracket 404 in the battery compartment 401, thereby improving the energy density of the energy storage device 2000.

[0090] Please refer to FIG. 5 and FIG. 6 . FIG. 5 is a schematic structural diagram of a battery cell 10 provided in some embodiments of the present application, and FIG. 6 is an exploded view of the battery cell 10 shown in FIG. 5 .

[0091] The battery cell 10 may include a housing 1 and an electrode assembly 2. The electrode assembly 2 may be one or more.

[0092] The electrode assembly 2 is a component where electrochemical reactions occur in the battery cell 10. The electrode assembly 2 may include a positive electrode sheet, a negative electrode sheet, and a separator.

[0093] The housing 1 is a component for accommodating the electrode assembly 2. The housing 1 may be in the shape of a right parallelepiped, for example, a cuboid, a cube, or the like.

[0094] The size of the housing 1 in the first direction X is W1, the size of the housing 1 in the second direction Y is T1, and the size of the housing 1 in the third direction Z is H1. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0095] For ease of description in the following embodiments, the first direction X is defined as the width direction of the battery cell 10, the second direction Y is defined as the thickness direction of the battery cell 10, and the third direction Z is defined as the height direction of the battery cell 10. In this case, W1 is the width of the battery cell 10, T1 is the thickness of the battery cell 10, and H1 is the height of the battery cell 10.

[0096] 5 to 8 , FIG. 7 is a cross-sectional exploded view of the battery cell 10 shown in FIG. 5 taken along an XZ plane, and FIG. 8 is a cross-sectional exploded view of the battery cell 10 shown in FIG. 5 taken along a YZ plane.

[0097] The housing 1 includes a first wall 101 and a second wall 102 arranged opposite to each other along a first direction X, a third wall 103 and a fourth wall 104 arranged opposite to each other along a second direction Y, and a fifth wall 105 and a sixth wall 106 arranged opposite to each other along a third direction Z. The six walls together form a space for accommodating the electrode assembly 2.

[0098] Among them, the sum of the thicknesses of the first wall 101 and the second wall 102 is a, the sum of the thicknesses of the third wall 103 and the fourth wall 104 is b, and the sum of the thicknesses of the fifth wall 105 and the sixth wall 106 is c, satisfying: (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥90%.

[0099] In this embodiment, the thicknesses of the first wall 101 and the second wall 102 may be equal or different; the thicknesses of the third wall 103 and the fourth wall 104 may be equal or different; and the thicknesses of the fifth wall 105 and the sixth wall 106 may be equal or different.

[0100] Since a, b, and c are all greater than 0, it can be understood that 90%≤(W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)<100%.

[0101] (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1) can be any value between 90% and 100%, for example, 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.5%, etc.

[0102] Among them, (W1-a)*(T1-b)*(H1-c) can be understood as the volume of the shell 1, that is, the volume of the space enclosed by the inner surface of the shell 1; W1*T1*H1 is the volume of the shell 1, which is approximately equal to the volume of the battery cell 10.

[0103] If the outer surfaces of the six walls of the housing 1 are all plane, then W is measured based on the outer surface of each wall. 1、 T1 and H1. For example, if the outer surface of the fifth wall 105 and the outer surface of the sixth wall 106 are both planes, then H1 is the distance between the outer surface of the fifth wall 105 and the outer surface of the sixth wall 106 along the third direction Z.

[0104] If a wall of the housing 1 has a convex or concave portion formed on its outer surface, W1, T1, and H1 are measured relative to the planar area of ​​that outer surface (i.e., the area excluding the convex or concave portion). For example, if the outer surface of the fifth wall 105 is planar and the outer surface of the sixth wall 106 has a first convex portion formed on its outer surface, H1 is the distance along the third direction Z between the planar area of ​​the outer surface of the sixth wall 106 excluding the first convex portion and the outer surface of the fifth wall 105. If the outer surface of the sixth wall 106 has a first convex portion formed on its outer surface and the outer surface of the fifth wall 105 has a second convex portion formed on its outer surface, H1 is the distance along the height direction of the battery cell 10 between the planar area of ​​the outer surface of the fifth wall 105 excluding the second convex portion and the planar area of ​​the outer surface of the sixth wall 106 excluding the first convex portion.

[0105] If the six walls of the housing 1 are all of uniform thickness, the distance between the outer surface and the inner surface of each wall can be measured from any position of the wall to obtain the thickness of the wall.

[0106] If a wall of the housing 1 has an uneven thickness, the thickness of the wall is calculated by measuring the distance between the outer and inner surfaces of the wall at the point where the wall has the greatest thickness. In other words, if the thickness of a wall is uneven, the maximum thickness of the wall is used to calculate a, b, or c.

[0107] In the embodiment of the present application, the ratio of the capacity of the outer shell 1 of the battery cell 10 to the volume of the outer shell 1 is set to be above 90%, so that the internal space of the outer shell 1 becomes larger and can accommodate a larger electrode assembly 2; under the same chemical material system, the volume energy density of the battery cell 10 can be improved.

[0108] The following is a detailed description based on specific experimental data:

[0109] In the experiment, the battery cell 21 is a square shell battery cell, the shell 11 is a hollow structure with one end open, and the number of the end cover 12 is one.

[0110] Table 1

[0111] According to Table 1 above, comparing Examples 1-4 with Comparative Example 1, it can be seen that when the positive electrode material of the battery cell 10 includes a lithium-containing phosphate, (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥0.9, which can effectively improve the volumetric energy density of the battery cell 10. Comparing Examples 5-8 with Comparative Example 2, it can be seen that when the positive electrode material of the battery cell 10 includes a lithium transition metal oxide, (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥0.9, which can effectively improve the volumetric energy density of the battery cell 10. Comparing Examples 9-12 with Comparative Example 3, it can be seen that when the battery cell 10 is a sodium ion battery cell, (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥0.9, which can effectively improve the volumetric energy density of the battery cell 10.

[0112] In order to make the ratio of the capacity of the shell 1 to the volume of the shell 1 above 90%, and make the proportion of the wall thickness of the shell 1 in three directions more uniform, the force balance of the shell 1 in three directions is improved.

[0113] In some embodiments, W1 and a satisfy (W1-a) / W1≥97.0%.

[0114] By setting the ratio of W1-a to W1 to 97.0% or greater, the width of the interior space of the housing 1 increases while the width of the battery cell 10 remains unchanged, thereby accommodating a wider electrode assembly 2. This also increases the volumetric energy density of the battery cell 10 while maintaining the same chemical material system. (W1-a) / W1 can be any value between 97.0% and 100%, for example, 97.0%, 97.5%, 98%, 98.5%, 99%, 99.5%, etc.

[0115] In some embodiments, T1 and b satisfy (T1-b) / T1≥96.5%.

[0116] By setting the ratio of T1-b to T1 to greater than 96.5%, the width of the interior space of the housing 1 is increased while the thickness of the battery cell 10 remains unchanged, thereby accommodating a thicker electrode assembly 2. This also increases the volumetric energy density of the battery cell 10 while maintaining the same chemical material system. (T1-b) / T1 can be any value between 96.5% and 100%, for example, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.5%, etc.

[0117] In some embodiments, H1 and c satisfy (H1-c) / H1≥96.5%.

[0118] By setting the ratio of H1-c to H1 to above 96.5%, the height of the interior space of the housing 1 is increased while the height of the battery cell 10 remains unchanged, thereby accommodating a taller electrode assembly 2. This also increases the volumetric energy density of the battery cell 10 while maintaining the same chemical material system. (H1-c) / H1 can be any value between 96.5% and 100%, for example, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.5%, etc.

[0119] In some embodiments, W1 and a satisfy (W1-a) / W1≥97.0%, T1 and b satisfy (T1-b) / T1≥96.5%, and H1 and c satisfy (H1-c) / H1≥96.5%.

[0120] As an example, the housing 1 may include a shell 11 and an end cover 12 .

[0121] The shell 11 can be a hollow structure with an opening at one end and a closed end, or the shell 11 can be a hollow structure with openings at two opposite ends. The opening is used for the electrode assembly 2 to enter the internal space of the shell 11. The end cover 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cover 12 and the shell 11 together define a sealed space for accommodating the electrode assembly 22, electrolyte and other components. The end cover 12 can be connected to the shell 11 by welding or rolling to close the opening of the shell 11. The shape of the end cover 12 can be adapted to the shape of the shell 11. For example, the shell 11 is a rectangular parallelepiped structure, and the end cover 12 is a rectangular plate structure adapted to the shell 11.

[0122] In the battery cell 10 , there may be one or two end covers 12 .

[0123] As shown in FIG6 , in an embodiment in which the housing 11 is a hollow structure with an opening formed at one end, an end cap 12 may be provided. The end cap 12 closes the opening at one end of the housing 11, and the end cap 12 and the housing 11 together define a sealed space. In this embodiment, the housing 11 includes an integrally formed first wall 101, a second wall 102, a third wall 103, a fourth wall 104, and a fifth wall 105. The first wall 101, the second wall 102, the third wall 103, and the fourth wall 104 serve as side walls of the housing 11, and the fifth wall 105 serves as the bottom wall of the housing 11. The sixth wall 106 is provided separately from the other five walls and serves as the end cap 12.

[0124] As shown in FIG10 , in an embodiment in which the housing 11 is a hollow structure with openings formed at both ends, two end caps 12 may be provided. The two end caps 12 respectively seal the two openings of the housing 11, and the two end caps 12 and the housing 11 together define a sealed space. In this embodiment, the housing 11 includes an integrally formed first wall 101, a second wall 102, a third wall 103, and a fourth wall 104. The fifth wall 105 is provided separately from the other five walls, and the sixth wall 106 is also provided separately from the other five walls. The fifth wall 105 serves as one end cap 12, and the sixth wall 106 serves as another end cap 12.

[0125] In order to reduce the possibility of interference between the electrode assembly 2 and the shell 11 during the process of being installed into the shell 11 and reduce the risk of damage to the electrode assembly 2, a certain assembly gap (i.e., shell entry gap) will be reserved for the electrode assembly 2 when designing the shell 11. The assembly gap can be 0.8-2mm.

[0126] In addition, in order to reduce the possibility of internal short circuit of the battery cell 10, an insulating member may be provided inside the housing 1. However, the insulating member will inevitably occupy a portion of the internal space of the housing 1, thereby reducing the space left for the electrode assembly 2.

[0127] 7 and 8, in some embodiments of the present application, the housing 1 includes a shell 11 and an end cap 12, the shell 11 has an opening, and the end cap 12 covers the opening; the shell 11 includes an integrally formed first wall 101, a second wall 102, a third wall 103, a fourth wall 104 and a fifth wall 105, and the end cap 12 is a sixth wall 106; the battery cell 10 also includes a first insulating member 141 and a second insulating member 142, the first insulating member 141 is disposed between the fifth wall 105 and the electrode assembly 2, and is in contact with the fifth wall 105. 5 abuts; the second insulating member 142 is disposed between the sixth wall 106 and the electrode assembly 2 and abuts against the sixth wall 106; the maximum dimension of the first insulating member 141 in the third direction Z is d1, and the maximum dimension of the second insulating member 142 in the third direction Z is d2, satisfying the following conditions: (W1-a-1.6mm)*(T1-b-1.6mm)*(H1-c-d1-d2) / (W1*T1*H1)≥88%, 0.3mm≤d1≤1.2mm, and 2mm≤d2≤10mm.

[0128] In this embodiment, W1-a-1.6mm indicates the maximum dimension of the internal space of the housing 1 reserved for the electrode assembly 2 along the first direction X, when the sum of the assembly clearances between the electrode assembly 2 and the first wall 101 and the assembly clearances between the electrode assembly 2 and the second wall 102 is 1.6mm. T1-b-1.6mm indicates the maximum dimension of the internal space of the housing 1 reserved for the electrode assembly 2 along the second direction Y, when the sum of the assembly clearances between the electrode assembly 2 and the third wall 103 and the assembly clearances between the electrode assembly 2 and the fourth wall 104 is 1.6mm. H1-c-d1-d2 indicates the maximum dimension of the internal space of the housing 1 reserved for the electrode assembly 2 along the third direction Z, when a first insulating member 141 is disposed between the fifth wall 105 and the electrode assembly 2, abutting the fifth wall 105, and a second insulating member 142 is disposed between the sixth wall 106 and the electrode assembly 2, abutting the sixth wall 106. The first insulating member 141 can be a bottom support plate, and the second insulating member 142 can be a lower plastic.

[0129] By setting the ratio of (W1-a-1.6mm)*(T1-b-1.6mm)*(H1-c-d1-d2) and W1*T1*H1 to above 88%, the space left for the electrode assembly 2 inside the outer shell 1 becomes larger, allowing a larger electrode assembly 2 to be placed, so that the volume energy density of the battery cell 10 is further improved.

[0130] In some embodiments of the present application, the following conditions are satisfied: (W1-a-4mm)*(T1-b-4mm)*(H1-c-d1-d2) / (W1*T1*H1)≥85%, 0.3mm≤d1≤10mm, and 2mm≤d2≤10mm.

[0131] In this embodiment, W1-a-4mm means: when the sum of the assembly gaps between the electrode assembly 2 and the first wall 101 and the assembly gaps between the electrode assembly 2 and the second wall 102 is 4 mm, the maximum size of the internal space of the housing 1 left for the electrode assembly 2 along the first direction X. T1-b-4mm means: when the sum of the assembly gaps between the electrode assembly 2 and the third wall 103 and the assembly gaps between the electrode assembly 2 and the fourth wall 104 is 4 mm, the maximum size of the internal space of the housing 1 left for the electrode assembly 2 along the second direction Y. H1-c-d1-d2 means: when a first insulating member 141 is provided between the fifth wall 105 and the electrode assembly 2, abutting the fifth wall 105, and a second insulating member 142 is provided between the sixth wall 106 and the electrode assembly 2, abutting the sixth wall 106, the maximum size of the internal space of the housing 1 left for the electrode assembly 2 along the third direction Z.

[0132] By setting the ratio of (W1-a-4mm)*(T1-b-4mm)*(H1-c-d1-d2) and W1*T1*H1 to above 85%, the space left for the electrode assembly 2 inside the outer shell 1 becomes larger, allowing a larger volume of electrode assembly 2 to be placed, so that the volume energy density of the battery cell 10 is further improved.

[0133] Please refer to Figures 9 to 12, Figure 9 is a structural schematic diagram of battery cells provided in other embodiments of the present application, Figure 10 is an exploded view of the battery cell shown in Figure 9, Figure 11 is a cross-sectional view of the battery cell shown in Figure 9 along the XZ plane, and Figure 12 is a cross-sectional view of the battery cell shown in Figure 9 along the YZ plane.

[0134] In some embodiments of the present application, the housing 1 includes a shell 11 and two end caps 12. The shell 11 has two openings arranged opposite to each other along the third direction Z, and the two end caps 12 respectively cover the openings on the corresponding sides; the shell 11 includes an integrally formed first wall 101, a second wall 102, a third wall 103 and a fourth wall 104, and the two end caps 12 are respectively the fifth wall and the sixth wall; the battery cell 10 also includes a third insulating member 143 and a fourth insulating member 144. The third insulating member 143 is arranged between the fifth wall 105 and the electrode assembly 2. And it abuts against the fifth wall 105; the fourth insulating member 144 is arranged between the sixth wall 106 and the electrode assembly 2, and abuts against the sixth wall 106; the maximum dimension of the third insulating member 143 in the third direction Z is d3, and the maximum dimension of the fourth insulating member 144 in the third direction Z is d4, satisfying: (W1-a-1.6mm)*(T1-b-1.6mm)*(H1-c-d3-d4) / (W1*T1*H1)≥88%, 2mm≤d3≤10mm, and 2mm≤d4≤10mm.

[0135] In this embodiment, the third insulating member and the fourth insulating member may be lower plastic.

[0136] By setting the ratio of (W1-a-1.6mm)*(T1-b-1.6mm)*(H1-c-d3-d4) and W1*T1*H1 to above 88%, the space left for the electrode assembly 2 inside the outer shell 1 becomes larger, allowing a larger electrode assembly 2 to be placed, so that the volume energy density of the battery cell 10 is further improved.

[0137] In some embodiments of the present application, the following conditions are satisfied: (W1-a-4mm)*(T1-b-4mm)*(H1-c-d3-d4) / (W1*T1*H1)≥85%, 2mm≤d3≤10mm, and 2mm≤d4≤10mm.

[0138] By setting the ratio of (W1-a-4mm)*(T1-b-4mm)*(H1-c-d3-d4) and W1*T1*H1 to above 85%, the space left for the electrode assembly 2 inside the outer shell 1 becomes larger, allowing a larger volume of electrode assembly 2 to be placed, so that the volume energy density of the battery cell 10 is further improved.

[0139] In some embodiments of the present application, W1, T1 and H1 satisfy: 3000cm 3 ≤W1*T1*H1≤40000cm 3 , that is, the volume of the housing 1 is 3000cm 3 ~40000cm 3 between.

[0140] When W1*T1*H1<3000cm 3 In order to make the ratio of the capacity of the shell 1 to the volume of the shell 1 above 90%, the wall thickness of the shell 1 needs to be designed to be smaller, which will result in a smaller load it can withstand. The structural strength and rigidity of the shell 1 are insufficient, and it is easy to deform or break, which is not conducive to the safety of the battery cell 10.

[0141] When W1*T1*H1>40000cm 3 When the battery cell 10 is large in size and capacity, the current during discharge of the battery cell 10 is large, which causes the overcurrent element in the circuit to generate a large amount of heat, and easily causes damage to the overcurrent element.

[0142] In this embodiment, by setting the volume of the housing 1 at 3000 cm 3 ~40000cm 3 On the one hand, when the ratio of the capacity to the volume of the housing 1 is above 90%, the wall thickness of the housing 1 is not too small, thereby meeting the requirements for the structural strength and rigidity of the housing 1; on the other hand, the capacity and current of the battery cell 10 can be controlled within a suitable range, reducing the risk of damage to overcurrent components in the circuit.

[0143] W1*T1*H1 can be 3000cm 3 ~40000cm 3 Any value between, for example, 3000cm 3 , 3100cm 3 , 3200cm 3 , 3300cm 3 , 3400cm 3 , 3500cm 3 , 3600cm 3 , 3700cm 3 , 3800cm 3, 3900cm 3 , 4000cm 3 , 4050cm 3 , 4100cm 3 , 4200cm 3 , 4500cm 3 , 5000cm 3 , 10000cm 3 , 15000cm 3 , 20000cm 3 , 25000cm 3 , 30000cm 3 , 35000cm 3 , 40000cm 3 wait.

[0144] In some embodiments, 3200 cm 3 ≤W1*T1*H1≤32000cm 3 .

[0145] For example, W1*T1*H1 can be 3200cm 3 ~32000cm 3 Any value between, for example, 3250cm 3 , 3350cm 3 , 3450cm 3 , 3550cm 3 , 3650cm 3 , 3750cm 3 , 3850cm 3 , 3950cm 3 , 4650cm 3 , 6650cm 3 , 9500cm 3 , 12000cm 3 , 18000cm 3 , 31000cm 3 wait.

[0146] In some embodiments, 3720 cm 3 ≤W1*T1*H1≤12500cm 3 .

[0147] In some embodiments, 4000 cm 3 ≤W1*T1*H1≤6000cm 3 .

[0148] Please refer to Figures 6, 13 to 16. Figure 13 is a front view of the two electrode assemblies 2 in Figure 6, Figure 14 is a side view of the two electrode assemblies 2 in Figure 6, Figure 15 is a top view of the two electrode assemblies 2 in Figure 6, and Figure 16 is a cross-sectional view of one electrode assembly 2 in Figure 6.

[0149] In some embodiments of the present application, the electrode assembly 2 includes a main body 21, a positive electrode ear 22 and a negative electrode ear 23, the positive electrode ear 22 and the negative electrode ear 23 extend from the main body 21, the main body 21 is a flat body, the maximum dimension of the main body 21 in the first direction X is W2, the maximum dimension of the main body 21 in the second direction Y is T2, and the maximum dimension of the main body 21 in the third direction Z is H2, satisfying: (W2*T2*H2) / (W1*T1*H1)≥80%.

[0150] The electrode assembly 2 includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on a portion of the positive electrode current collector. The positive electrode active material layer and the area of ​​the positive electrode current collector coated with the positive electrode active material layer form a positive electrode coating area, and the area of ​​the positive electrode current collector not coated with the positive electrode active position layer forms a positive electrode ear 22, and the positive electrode ear 22 protrudes from the positive electrode coating area. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on a portion of the negative electrode current collector. The negative electrode active material layer and the area of ​​the negative electrode current collector coated with the negative electrode active material layer form a negative electrode coating area, and the area of ​​the negative electrode current collector not coated with the negative electrode active position layer forms a negative electrode ear 23, and the negative electrode ear 23 protrudes from the negative electrode coating area.

[0151] The positive electrode coating region and the negative electrode coating region are disposed opposite to each other, and the positive electrode coating region, the negative electrode coating region, and the separator form a main body 21 of the electrode assembly 2 .

[0152] The electrode assembly 2 can be a wound structure formed by winding a positive electrode sheet, a separator, and a negative electrode sheet, or a laminated structure formed by stacking a positive electrode sheet, a separator, and a negative electrode sheet. It is understood that regardless of whether the electrode assembly 2 has a wound structure or a laminated structure, the main body 21 can be flat.

[0153] It should be noted that when a battery cell 10 is provided with multiple electrode assemblies 2, W2 is the maximum dimension of the entire body consisting of the main bodies 21 of the multiple electrode assemblies 2 in the first direction X, T2 is the maximum dimension of the entire body consisting of the main bodies 21 of the multiple electrode assemblies 2 in the second direction Y, and H2 is the maximum dimension of the entire body consisting of the main bodies 21 of the multiple electrode assemblies 2 in the third direction Z. As an example, as shown in Figures 6 and 15, two electrode assemblies 2 are provided in the housing 1, and the two electrode assemblies 2 are stacked along the second direction Y. In this case, T2 is the maximum dimension of the entire body consisting of the main bodies 21 of the two electrode assemblies 2 in the second direction Y.

[0154] In this embodiment, by setting (W2*T2*H2) / (W1*T1*H1) to more than 80%, the electrode assembly 2 can fully utilize the internal space of the outer shell 1, and the situation where the volume of the outer shell 1 is large and the volume of the electrode assembly 2 is small will not occur. The volume energy density of the battery cell 10 is improved, and the movement of the electrode assembly 2 in the outer shell 1 is reduced.

[0155] (W2*T2*H2) / (W1*T1*H1) can be any value between 80% and 100%, for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 92%, 94%, 96%, etc.

[0156] In order to make the ratio of W2*T2*H2 to W1*T1*H1 above 80%, and to make the dimensions of the main body 21 of the electrode assembly 2 in various directions match the dimensions of the internal space of the outer shell 1 in various directions, so as to further reduce the movement of the electrode assembly 2 in the outer shell 1, in some embodiments, it is satisfied that: W2 / (W1-a) ≥ 91.5%, T2 / (T1-b) ≥ 93.2%, and H2 / (H1-c) ≥ 94.0%.

[0157] By setting the ratio of W2 to W1-a to 91.5% or greater, the space utilization within the housing 1 in the first direction X can be improved; using the same chemical material system, the volumetric energy density of the battery cell 10 can be increased. The ratio of W2 to W1-a can be any value greater than 91.5%, for example, 91.6%, 91.8%, 92.0%, 92.5%, 93.0%, 93.5%, 94.0%, 94.5%, 95.0%, etc.

[0158] By setting the ratio of T2 to T2-b to 93.2% or greater, the space utilization within the housing 1 in the second direction Y can be improved; using the same chemical material system, the volumetric energy density of the battery cell 10 can be increased. The ratio of T2 to T2-b can be any value greater than 93.2%, for example, 93.5%, 94.0%, 94.5%, 95.0%, 95.5%, 96.0%, 96.5%, 97.0%, 97.5%, etc.

[0159] By setting the ratio of H2 to H1-c to 94.0% or greater, the space utilization within the housing 1 in the third direction Z can be improved; using the same chemical material system, the volumetric energy density of the battery cell 10 can be increased. The ratio of H2 to H1-c can be any value greater than 94.0%, for example, 94.5%, 95.0%, 95.5%, 96.0%, 96.5%, 97.0%, 97.5%, 98.0%, 98.5%, etc.

[0160] In the embodiments shown in Figures 6 and 13 to 16 , the electrode assembly 2 is a wound structure, the winding centerline of the electrode assembly 2 is arranged along the third direction Z, and the positive electrode tab 22 and the negative electrode tab 23 are located at the same end of the main body 21 and are both arranged toward the end cap 12. However, the embodiments of the present application are not limited thereto.

[0161] Please refer to Figures 17 to 19. Figure 17 is an exploded view of a battery cell provided in some other embodiments of the present application. Figure 18 is a front view of the electrode assembly in Figure 17. Figure 19 is a top view of the electrode assembly in Figure 17.

[0162] In some other embodiments of the present application, the electrode assembly 2 is a wound structure, the winding center line of the electrode assembly 2 is set along the first direction X, the positive electrode ear 22 and the negative electrode ear 23 are located at opposite ends of the main body 21, the positive electrode ear 22 is set toward the first wall 101, and the negative electrode ear 23 is set toward the second wall 102.

[0163] Referring to Figure 16 , when the electrode assembly 2 has a wound structure, the main body 21 may include a straight region A, a first bending region B1, and a second bending region B2, with the first bending region B1 and the second bending region B2 located at opposite ends of the straight region A. In the straight region A, the positive electrode sheet 24, the negative electrode sheet 25, and the separator 26 are generally planar. In the first bending region B1 and the second bending region B2, the positive electrode sheet 24, the negative electrode sheet 25, and the separator 26 are all curved or arcuate.

[0164] In some embodiments of the present application, along the first direction X, the first bending region B1 and the second bending region B2 are respectively located at opposite ends of the straight region A, that is, the first bending region B1, the straight region A, and the second bending region B2 are arranged along the first direction X, and the winding centerline direction of the electrode assembly 2 is the third direction Z. In this embodiment, the first bending region B1 includes a plurality of first bending portions arranged in a stacked manner, and along the first direction X, the distance between the inner vertex of the innermost first bending portion of the plurality of first bending portions and the outer vertex of the outermost first bending portion is W3; the second bending region B2 includes a plurality of second bending portions arranged in a stacked manner, and along the first direction X, the distance between the inner vertex of the innermost second bending portion of the plurality of second bending portions and the outer vertex of the outermost second bending portion is W4; and the following condition is satisfied: (W3+W4) / W2≤30%.

[0165] The "innermost first bend of the plurality of first bends" refers to the first bend closest to the winding centerline of the electrode assembly 2. If the innermost layer of the electrode assembly 2 is the separator 26, then the innermost first bend is the bend of the separator 26. If the innermost layer of the electrode assembly 2 is the positive electrode sheet 24, then the innermost first bend is the bend of the positive electrode sheet 24. If the innermost layer of the electrode assembly 2 is the negative electrode sheet 25, then the innermost first bend is the bend of the negative electrode sheet 25.

[0166] The “inner vertex of the first bend of the innermost layer” refers to the point on the inner surface of the first bend of the innermost layer (i.e., the surface facing the winding center line of the electrode assembly 2) that is farthest from the winding center line of the electrode assembly 2.

[0167] The "innermost second bend of the plurality of second bends" refers to the second bend closest to the winding centerline of the electrode assembly 2. If the innermost layer of the electrode assembly 2 is the separator 26, then the innermost second bend is the bend of the separator 26. If the innermost layer of the electrode assembly 2 is the positive electrode sheet 24, then the innermost second bend is the bend of the positive electrode sheet 24. If the innermost layer of the electrode assembly 2 is the negative electrode sheet 25, then the innermost second bend is the bend of the negative electrode sheet 25.

[0168] The “inner vertex of the innermost second bend portion” refers to the point on the inner surface of the innermost second bend portion (i.e., the surface facing the winding center line of the electrode assembly 2) that is farthest from the winding center line of the electrode assembly 2.

[0169] Because the housing 1 is in the shape of a straight parallelepiped, unlike the flat region A, the bent region does not completely align with the inner surface of the housing 1, leaving a gap between them. The larger the bent region's dimension in the first direction X, the larger the gap, and the lower the effective utilization of the internal space of the housing 1.

[0170] In this embodiment, W3 is approximately equal to the dimension of the first bending zone B1 in the first direction X, and W4 is approximately equal to the dimension of the second bending zone B2 in the first direction X. By setting the ratio of the sum of W3 and W4 to W2 to be less than 30%, the proportion of the dimensions of the first bending zone B1 and the second bending zone B2 in the first direction X is reduced, and the proportion of the dimension of the straight area A in the first direction X is increased, thereby reducing the volume ratio of the aforementioned gap, thereby improving the effective utilization of the internal space of the housing 1 and increasing the volume energy density of the battery cell 10.

[0171] At 3000cm 3 ≤W1*T1*H1≤40000cm 3, and (W2*T2*H2) / (W1*T1*H1) ≥ 80%, the volume of the battery cell 10 is large, and so is the volume of the electrode assembly 2. Under the same chemical material system, the larger the volume of the electrode assembly 2, the greater its mass. However, when the battery cell 10 is dropped or collided, the electrode assembly 2 will move within the outer casing 1. In this case, the larger the mass of the electrode assembly 2, the greater the impact on the outer casing 1.

[0172] In order to enable each wall of the shell 1 to withstand a larger impact, reduce the risk of deformation of the shell 1, and improve the reliability of the battery cell 10, in some embodiments of the present application, the material of the first wall 101, the second wall 102, the third wall 103, the fourth wall 104, the fifth wall 105 and the sixth wall 106 all include aluminum alloy, and the aluminum alloy includes the following components in mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

[0173] In this embodiment, by controlling the mass percentages of various elements within the above range, a stronger aluminum alloy can be obtained. Using this aluminum alloy as the material of the shell 1 can significantly improve the shell 1's ability to resist impact and enhance the reliability of the battery cell 10.

[0174] Please refer to Figures 7 and 8. In some embodiments of the present application, the shell 1 includes a shell 11 and an end cover 12. The shell 11 has an opening, the end cover 12 covers the opening, and the end cover 12 is welded to the shell 11; the first wall 101, the second wall 102, the third wall 103, the fourth wall 104 and the fifth wall 105 are integrally formed and serve as the shell 11, the sixth wall 106 is separately formed from the other five walls, and the sixth wall 106 serves as the end cover 12; the thickness of the first wall 101 and the second wall 102 is both a1, the thickness of the third wall 103 and the fourth wall 104 is both b1, the thickness of the fifth wall 105 is c1, and the thickness of the sixth wall 106 is c2, satisfying: c2>c1, c1>a1, c1>b1.

[0175] For a battery cell 10 having only one end cover, the battery cell 10 is usually used with the end cover facing up or down. When the battery cell 10 is used with the end cover facing up, particulate matter (such as carbon powder, metal chips, etc.) inside the battery cell 10 will be deposited on the bottom of the shell (i.e., the fifth wall 105) due to gravity, causing the bottom of the shell to be corroded. After long-term corrosion, the strength of the bottom of the shell will be weakened, which is not conducive to resisting impacts from the electrode assembly 2 or the outside, and affecting the reliability of the battery cell 10. Therefore, in this embodiment, the thickness of the fifth wall 105 is designed to be thicker, so that the thickness of the fifth wall 105 is greater than the thickness of the first wall 101 and the second wall 102, and greater than the thickness of the third wall 103 and the fourth wall 104 (i.e., c1>a1, c1>b1).

[0176] In addition, at 3000cm 3 ≤W1*T1*H1≤40000cm 3 , and (W2*T2*H2) / (W1*T1*H1) ≥ 80%, the volume of the battery cell 10 is larger, and the volume of the electrode assembly 2 is also larger. Under the same chemical material system, the larger the volume of the electrode assembly 2, the greater the gas production of the battery cell 10 during circulation, and the greater the internal gas pressure of the battery cell 10.

[0177] In order to reduce the risk of tearing of the weld between the end cap 12 and the shell 11 due to increased internal air pressure, in this embodiment, the thickness of the end cap 12 is designed to be thicker, so that the thickness of the end cap 12 is greater than the thickness of the fifth wall 105 (i.e., c2>c1). This allows a weld with a larger width or thickness to be formed between the end cap 12 and the shell 11, thereby improving the welding strength, reducing the risk of the weld tearing, and improving the reliability of the battery cell 10. In addition, in order to form a weld with a larger width or thickness, increasing the thickness of the end cap 12 can reduce the amount of material used and reduce costs compared to increasing the thickness of the shell 11. Increasing the thickness of the shell 11 means increasing the thickness of at least the first wall 101, the second wall 102, the third wall 103, and the fourth wall 104 welded to the end cap 12, which significantly increases the amount of material used and is costly.

[0178] When the first wall 101, the second wall 102, the third wall 103, the fourth wall 104 and the fifth wall 105 are integrally formed and serve as a shell, and the sixth wall 106 serves as the end cover 12, in some embodiments of the present application, the area of ​​the third wall 103 and the fourth wall 104 is greater than the area of ​​the first wall 101 and the second wall 102, and the area of ​​the third wall 103 and the fourth wall 104 is greater than the area of ​​the fifth wall 105 and the sixth wall 106, satisfying: b1<a1.

[0179] In this embodiment, the third wall 103 and the fourth wall 104 are the two walls with the largest areas of the housing 1, that is, the large surfaces of the battery cell 10. During cycling, the electrode assembly 2 expands significantly more in the large surface direction than in other directions. To allow for expansion of the electrode assembly 2 in the large surface direction, in this embodiment, the thickness of the third wall 103 and the fourth wall 104 are designed to be smaller, making them thinner than the thickness of the first wall 101 and the second wall 102 (i.e., b1 < a1).

[0180] When the first wall 101, the second wall 102, the third wall 103, the fourth wall 104 and the fifth wall 105 are integrally formed and serve as the shell 11, and the sixth wall 106 serves as the end cover 12, in some embodiments of the present application, 0.5mm≤a1≤1.5mm, 0.5mm≤b1≤1.5mm, 1.0mm≤c1≤2.5mm, and 1.5mm≤c2≤4mm.

[0181] a1 can be any value between 0.5mm and 1.5mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0182] When a1 is less than 0.5 mm, the thickness of the first wall 101 and the second wall 102 is too small. Since the thickness of the third wall 103 and the fourth wall 104 is smaller than that of the first wall 101 and the second wall 102, it is difficult to ensure the structural strength of the housing 1 in the third direction Z, and the battery cell 10 is easily deformed. When a1 is greater than 1.5 mm, the thickness of the first wall 101 and the second wall 102 is too large, which is not conducive to improving the volumetric energy density of the battery cell 10 and is costly. In this embodiment, setting a1 to 0.5 mm to 1.5 mm ensures the volumetric energy density of the battery cell 10 while also ensuring the structural strength of the housing 1 in the third direction Z.

[0183] b1 can be any value between 0.5mm and 1.5mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0184] When b1 is less than 0.5 mm, the thickness of the third wall 103 and the fourth wall 104 is too small. When the electrode assembly 2 expands, the third wall 103 and the fourth wall 104 are easily squeezed and ruptured. When b1 is greater than 1.5 mm, the thickness of the third wall 103 and the fourth wall 104 is too large, and the structural strength and rigidity are also greater, making it difficult to absorb the expansion of the electrode assembly 2. This can easily lead to stress concentration inside the electrode assembly 2, causing "lithium deposition" and resulting in a decrease in cycle life. In this embodiment, b1 is set to 0.5 mm to 1.5 mm, so that the structural strength and rigidity of the third wall 103 and the fourth wall 104 are moderate, allowing the electrode assembly 2 to expand without being squeezed and ruptured by the electrode assembly 2.

[0185] c1 can be any value between 1.0 mm and 2.5 mm, for example, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, etc.

[0186] When c1 is less than 1.0 mm, the thickness of the fifth wall 105 is too small. After long-term corrosion by particles deposited thereon, the residual thickness of the fifth wall 105 is even smaller. When the electrode assembly 2 moves within the housing 1, the fifth wall 105 is unable to withstand the impact of the electrode assembly 2 and is prone to rupture. When c1 is greater than 2.5 mm, the thickness of the fifth wall 105 is too large, which is not conducive to improving the volumetric energy density of the battery cell 10 and is also costly. In this embodiment, setting c1 to 1.0 mm to 2.5 mm ensures that the volumetric energy density of the battery cell 10 is maintained while also ensuring that the fifth wall 105 can withstand the impact of the electrode assembly 2.

[0187] When the first wall 101, the second wall 102, the third wall 103, the fourth wall 104, and the fifth wall 105 are integrally formed and serve as the housing 11, and the sixth wall 106 serves as the end cap 12, the electrode terminal can be provided on the end cap 12 or on the fifth wall 105. The electrode terminal is electrically connected to the electrode assembly 2.

[0188] When the first wall 101, the second wall 102, the third wall 103, the fourth wall 104 and the fifth wall 105 are integrally formed and serve as a shell, and the sixth wall 106 serves as an end cover, in order to further increase the volume ratio of the internal space of the shell 1 and improve the volume energy density of the battery cell 10, in some embodiments of the present application, (W1-2*a1)*(T1-2*b1)*(H1-c1-c2) / (W1*T1*H1)≥95%.

[0189] Please refer to Figures 10 to 12. In some embodiments of the present application, the housing 1 includes a shell 11 and two end covers 12. The shell 11 has two openings arranged opposite to each other along the third direction Z. The two end covers 12 respectively cover the openings on the corresponding sides, and the end covers 12 are welded to the shell 11; the first wall 101, the second wall 102, the third wall 103 and the fourth wall 104 are integrally formed and serve as the shell 11, and the fifth wall 105 and the sixth wall 106 serve as two end covers 12 respectively; the thickness of the first wall 101 and the second wall 102 is both a1, the thickness of the third wall 103 and the fourth wall 104 is both b1, the thickness of the fifth wall 105 is c1, and the thickness of the sixth wall 106 is c2, satisfying: c1=c2, c1>a1, c2>b1.

[0190] In this embodiment, by setting the fifth wall 105 and the sixth wall 106 to have equal thickness (ie, c1 = c2), the two end caps 12 required for the battery cell 10 can be produced using the same set of molds, thereby reducing the number of molds and lowering production costs.

[0191] For battery cells 10 with two end caps 12, to reduce the risk of tearing the weld between the end caps 12 and the housing 11 due to increased internal air pressure, in this embodiment, the thickness of the end caps 12 is designed to be thicker. Such thickness is greater than the thickness of the first and second walls 101, 102, and greater than the thickness of the third and fourth walls 103, 104 (i.e., c1>a1, c1>b1, c2>a1, c2>b1). This allows for a wider or thicker weld to be formed between the end caps 12 and the housing 11, thereby increasing weld strength, reducing the risk of weld tearing, and improving the reliability of the battery cell 10. Furthermore, to form a wider or thicker weld, increasing the thickness of the end caps 12 can reduce material usage and reduce costs, compared to increasing the thickness of the first, second, third, and fourth walls 101, 102, 103, and 104.

[0192] When the first wall 101, the second wall 102, the third wall 103 and the fourth wall 104 are integrally formed and serve as the shell 11, and the fifth wall 105 and the sixth wall 106 serve as end covers 12 respectively, in some embodiments of the present application, the area of ​​the third wall 103 and the fourth wall 104 is greater than the area of ​​the first wall 101 and the second wall 102, and the area of ​​the third wall 103 and the fourth wall 104 is greater than the area of ​​the fifth wall 105 and the sixth wall 106, satisfying: b1<a1.

[0193] In this embodiment, the third wall 103 and the fourth wall 104 are the two walls with the largest area of ​​the housing 1, that is, the large surfaces of the battery cell 10. Generally, during cycling of the battery cell 10, the electrode assembly 2 expands much more in the large surface direction than in other directions. To allow for expansion of the electrode assembly 2 in the large surface direction, in this embodiment, the thickness of the third wall 103 and the fourth wall 104 are designed to be smaller, such that the thickness of the third wall 103 and the fourth wall 104 is less than the thickness of the first wall 101 and the second wall 102 (i.e., b1 < a1).

[0194] When the first wall 101, the second wall 102, the third wall 103 and the fourth wall 104 are integrally formed and serve as the shell 11, and the fifth wall 105 and the sixth wall 106 serve as the end covers 12 respectively, in some embodiments of the present application, 0.5mm≤a1≤1.5mm, 0.5≤b1≤1.5mm, and 1.5mm≤c1≤4mm.

[0195] a1 can be any value between 0.5mm and 1.5mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0196] When a1 is less than 0.5 mm, the thickness of the first wall 101 and the second wall 102 is too small. Since the thickness of the third wall 103 and the fourth wall 104 is smaller than that of the first wall 101 and the second wall 102, it is difficult to ensure the structural strength of the housing 1 in the third direction Z, and the battery cell 10 is easily deformed. When a1 is greater than 1.5 mm, the thickness of the first wall 101 and the second wall 102 is too large, which is not conducive to improving the volumetric energy density of the battery cell 10 and is costly. In this embodiment, setting a1 to 0.5 mm to 1.5 mm ensures the volumetric energy density of the battery cell 10 while also ensuring the structural strength of the housing 1 in the third direction Z.

[0197] b1 can be any value between 0.5mm and 1.5mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0198] When b1 is less than 0.5 mm, the thickness of the third wall 103 and the fourth wall 104 is too small. When the electrode assembly 2 expands, the third wall 103 and the fourth wall 104 are easily squeezed and ruptured. When b1 is greater than 1.5 mm, the thickness of the third wall 103 and the fourth wall 104 is too large, and the structural strength and rigidity are also greater, making it difficult to absorb the expansion of the electrode assembly 2. This can easily lead to stress concentration inside the electrode assembly 2, causing "lithium deposition" and resulting in a decrease in cycle life. In this embodiment, b1 is set to 0.5 mm to 1.5 mm, so that the structural strength and rigidity of the third wall 103 and the fourth wall 104 are moderate, allowing the electrode assembly 2 to expand without being squeezed and ruptured by the electrode assembly 2.

[0199] c1 and c2 can be any value between 1.5mm and 4.0mm, for example, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3.0mm, 3.2mm, 3.5mm, 3.8mm, 4.0mm, etc.

[0200] When c1 and c2 are less than 1.5 mm, the thickness of the end cap 12 is too small. After long-term corrosion by particles deposited on the end cap 12, the residual thickness is even smaller. When the electrode assembly 2 moves within the housing 1, the end cap 12 cannot withstand the impact of the electrode assembly 2 and is prone to cracking. When c1 and c2 are greater than 4 mm, the thickness of the end cap 12 is too large, which is not conducive to improving the volumetric energy density of the battery cell 10 and is also costly. In this embodiment, setting c1 and c2 to 1.5 mm to 4 mm ensures that the volumetric energy density of the battery cell 10 is maintained while ensuring the end cap's ability to withstand the impact of the electrode assembly 2.

[0201] When the first wall 101, the second wall 102, the third wall 103, and the fourth wall 104 are integrally formed and serve as the housing 11, and the fifth wall 105 and the sixth wall 106 serve as end caps 12, the electrode terminals are provided on the end caps 12, and the electrode terminals are electrically connected to the electrode assembly 2. Furthermore, the positive electrode terminal 121 may be provided on one end cap 12, and the negative electrode terminal 122 may be provided on the other end cap 12.

[0202] When the first wall 101, the second wall 102, the third wall 103 and the fourth wall 104 are integrally formed to form the shell 11, and the fifth wall 105 and the sixth wall 106 respectively serve as the end caps 12, in order to further increase the volume ratio of the internal space of the shell 1 and improve the volume energy density of the battery cell 10, in some embodiments of the present application, (W1-2*a1)*(T1-2*b1)*(H1-2*c1) / (W1*T1*H1)≥95%.

[0203] In some embodiments of the present application, W1 , T1 , and H1 satisfy: T1 < W1 , T1 < H1 , that is, the third wall 103 and the fourth wall 104 are the two walls with the largest areas of the housing 1 .

[0204] In this embodiment, the thickness of the battery cell 10 is smaller than its width and height. The battery cell 10 is flat, and the battery assembly is also flat. The thickness direction of the electrode assembly 2 is the same as the thickness direction of the battery cell 10. For a laminated electrode assembly 2, the thickness direction of the electrode assembly 2 is the stacking direction of the electrode sheets. For a wound electrode assembly 2, the main body 21 of the electrode assembly 2 includes a straight region A, a first bending region B1, and a second bending region B2. The thickness direction of the electrode assembly 2 is the stacking direction of the electrode sheets in the straight region A.

[0205] Whether it is a laminated or wound electrode assembly, the thickness of the electrode assembly 2 cannot be too large. If it is too large, the heat of the inner electrode sheets cannot be dissipated outward in a timely manner, causing the inner electrode sheets to overheat and easily cause thermal runaway. Because the thickness of the electrode assembly 2 cannot be too large, the thickness of the battery cell 10 cannot be too large either.

[0206] In the case where the thickness of the battery cell 10 is limited, in order to make the volume of the battery cell 10 reach 3000 cm 3 As described above, in some embodiments of the present application, the width and height of the battery cell 10 are both greater than or equal to twice the thickness of the battery cell 10 , that is, W1 / T1 ≥ 2, H1 / T1 ≥ 2.

[0207] However, when the width of the battery cell 10 exceeds ten times its thickness, or the height exceeds ten times its thickness, the battery cell 10 becomes a long, thin rectangular parallelepiped, and the overall rigidity of the battery cell 10 is insufficient, making it prone to deformation. To this end, in some embodiments of the present application, W1, T1, and H1 satisfy the following conditions: 2≤W1 / T1≤10, 2≤H1 / T1≤10. This ensures that the battery cell 10 has a larger volume while maintaining greater overall rigidity and preventing deformation.

[0208] In some embodiments of the present application, W1 and H1 satisfy: 0.7≤W1 / H1≤1.6.

[0209] When W1 / H1 is less than 0.7, the width of the battery cell 10 is much smaller than its height. As the two walls with the largest area of ​​the outer shell 1, the third wall 103 and the fourth wall 104 are narrow and long plates, which makes it difficult to ensure the structural strength and rigidity of the battery cell 10 in the width direction. When the first wall 101 and / or the second wall 102 are subjected to external force along the width direction of the battery cell 10, the third wall 103 and the fourth wall 104 are prone to bending and deformation.

[0210] When W1 / H1>1.6, the width of the battery cell 10 is much larger than its height. As the two walls with the largest area of ​​the outer shell 1, the third wall 103 and the fourth wall 104 are narrow and long plates, which makes it difficult to ensure the structural strength and rigidity of the battery cell 10 in the height direction. When the fifth wall 105 and / or the sixth wall 106 are subjected to external force along the height direction of the battery cell 10, the third wall 103 and the fourth wall 104 are prone to bending and deformation.

[0211] In this embodiment, by setting the ratio of W1 to H1 between 0.7 and 1.6, the width and height of the battery cell 10 are made closer, thereby improving the structural strength and rigidity of the battery cell 10 in the width and height directions and reducing the possibility of deformation of the battery cell 10.

[0212] W1 / H1 can be any value between 0.7 and 1.6, for example, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, etc.

[0213] In some embodiments of the present application, 40 mm ≤ T1 ≤ 150 mm. T1 can be any value between 40 mm and 150 mm, for example, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, 150 mm, etc.

[0214] When T1 is less than 40 mm, if (T1-b) / T1≥96.5% is to be satisfied, the value of b needs to be set very small. However, when the value of b is too small, it is difficult to ensure the structural strength and rigidity of the third wall 103 and the fourth wall 104.

[0215] When T1>150mm, the heat dissipation path of the inner electrode of the electrode assembly 2 is likely to be too long, and the heat of the inner electrode cannot be diffused outward in time, causing the temperature of the inner electrode to be too high, which is likely to cause thermal runaway.

[0216] In this embodiment, by setting T1 between 40 mm and 150 mm, it is possible to increase the size ratio of the internal space of the shell 1 in the thickness direction of the battery cell 10, thereby increasing the volume energy density of the battery cell 10, while ensuring the timely heat dissipation of the inner electrode of the electrode assembly 2.

[0217] In some embodiments of the present application, the height direction of the battery cell 10 is parallel to the direction of gravity, the battery cell 10 includes an electrolyte, and 120 mm ≤ H1 ≤ 400 mm. H1 can be any value between 120 mm and 400 mm, for example, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 210 mm, 220 mm, 230 mm, 240 mm, 250 mm, 260 mm, 270 mm, 280 mm, 290 mm, 300 mm, 310 mm, 320 mm, 330 mm, 340 mm, 350 mm, 360 mm, 370 mm, 380 mm, 390 mm, 400 mm, etc.

[0218] When H1 is less than 120 mm, to satisfy (H1-c) / H1≥96.5%, the value of c needs to be set very small. However, the fifth wall 105 and / or the sixth wall 106 are end covers. If the value of c is too small, the weld between the end cover and the shell will be small, making it difficult to ensure weld strength.

[0219] When H1>400mm, the height of the battery cell 10 and the electrode assembly 2 is too high. Since the height direction of the battery cell 10 is parallel to the direction of gravity, the excessive height of the electrode assembly 2 will make it difficult for the electrolyte to reach the top of the electrode assembly 2. The top of the electrode assembly 2 cannot be fully infiltrated by the electrolyte and cannot function, resulting in a decrease in the energy density of the battery cell 10.

[0220] In this embodiment, by setting H1 between 120 mm and 400 mm, it is possible to increase the size ratio of the internal space of the shell 1 in the height direction of the battery cell 10, thereby increasing the volume energy density of the battery cell 10, while ensuring that the top of the electrode assembly 2 can be fully infiltrated by the electrolyte.

[0221] In some embodiments of the present application, 150 mm ≤ W1 ≤ 1500 mm. W1 can be any value between 150 mm and 1500 mm, for example, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, 800 mm, 850 mm, 900 mm, 950 mm, 1000 mm, 1050 mm, 1100 mm, 1150 mm, 1200 mm, 1250 mm, 1300 mm, 1350 mm, 1400 mm, 1450 mm, 1500 mm, etc.

[0222] When W1 is less than 150 mm, if (W1-a) / W1≥97.0% is to be satisfied, the value of a needs to be set very small. However, when the value of a is too small, it is difficult to ensure the structural strength and rigidity of the first wall 101 and the second wall 102. In addition, due to the heat dissipation of the electrode assembly 2, T1 cannot be too large, and due to the infiltration of the electrode assembly 2, H1 cannot be too large. If T1 is also too small, the volume of the battery cell 10 cannot be greater than or equal to 3000 cm. 3 , it is difficult to ensure the volume energy density of the battery cell 10.

[0223] When W1>1500mm, due to the limitations of T1 and H1, W1 and T1 differ greatly, and W1 and H1 differ greatly, making the battery cell 10 as a whole an elongated rectangular structure, and the overall structural strength and rigidity of the battery cell 10 are insufficient.

[0224] In this embodiment, by setting W1 between 150 mm and 1500 mm, the internal space of the housing 1 can be increased in proportion to the width of the battery cell 10 to increase the volume energy density of the battery cell 10, while ensuring the overall structural strength and rigidity of the battery cell 10.

[0225] In some embodiments of the present application, battery cell 10 is a lithium-ion battery. The positive electrode active material of battery cell 10 includes a lithium-containing phosphate. The capacity of battery cell 10 is C, satisfying the following conditions: C ≥ 350 Ah, and C / ((W1-a)*(T1-b)*(H1-c)) ≥ 118 Ah / L. As specific examples, the lithium-containing phosphate may include, but is not limited to, one or more of lithium iron phosphate, lithium manganese phosphate, lithium cobalt phosphate, and lithium nickel phosphate.

[0226] In some embodiments of the present application, the positive electrode active material of the battery cell 10 includes a lithium transition metal oxide, and the capacity of the battery cell 10 is C, satisfying the following: C ≥ 650 Ah, C / ((W1-a)*(T1-b)*(H1-c)) ≥ 190 Ah / L. As specific examples, the lithium transition metal oxide may include, but is not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0227] In some embodiments of the present application, the battery cell 10 is a sodium ion battery, and the capacity of the battery cell 10 is C, satisfying: C≥260Ah, C / ((W1-a)*(T1-b)*(H1-c))≥87Ah / L.

[0228] An embodiment of the present application provides a battery 100 , including a battery case 20 and a battery cell 10 provided in any one of the above embodiments, wherein the battery cell 10 is accommodated in the battery case 20 .

[0229] An embodiment of the present application provides an electrical device, comprising a battery provided by any one of the above embodiments.

[0230] An embodiment of the present application provides an energy storage device 2000 , including an energy storage box 400 and a battery cell 10 provided in any one of the above embodiments. The energy storage box 400 includes a battery compartment 401 , and the battery cell 10 is accommodated in the battery compartment 401 .

[0231] In some embodiments of the present application, the sum of the volumes of the plurality of battery cells 10 is V1, and the volume of the battery compartment 401 is V2, satisfying the following relationship: 0.5 ≤ V1 / V2 ≤ 0.95. V1 / V2 can be any value between 0.5 and 0.95, for example, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0232] V1 is the sum of the volumes of all battery cells 10 within the battery compartment. If the volumes of all battery cells 10 within battery compartment 401 are equal, V1 is the product of the volume of each battery cell 10 and the number of battery cells 10. V2 is the volume of the three-dimensional space defined by the inner contour of battery compartment 401. In energy storage device 2000, V1 / V2 can be defined as the space utilization ratio.

[0233] In this embodiment, by limiting the ratio of the sum of the volumes of the battery cells 10 to the volume of the battery compartment, that is, V1 / V2 ≥ 0.5, the space utilization rate of the energy storage device 2000 can be improved, and more battery cells 10 can be arranged in the battery compartment 401 of the energy storage box 400, that is, more energy supply structures can be arranged in a unit space, thereby increasing the energy density and thus increasing the capacity without expanding the occupied space.

[0234] In some embodiments of the present application, the ratio of the sum of the volumes of the plurality of battery cells 10 to the volume of the battery compartment 401 satisfies: V1 / V2≥0.55.

[0235] In some embodiments of the present application, the ratio of the sum of the volumes of the plurality of battery cells 10 to the volume of the battery compartment 401 satisfies: V1 / V2≥0.65.

[0236] In some embodiments of the present application, the ratio of the sum of the volumes of the plurality of battery cells 10 to the volume of the battery compartment 401 satisfies: V1 / V2≥0.75.

[0237] It will be understood by those skilled in the art that since other components used in conjunction with the battery cell 10 will occupy the internal space of the battery compartment, including the liquid cooling system, control system, wiring harness, etc., the peak value of V1 / V2 is usually 95%, that is, V1 / V2≤95%.

[0238] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0239] The above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit this application. Those skilled in the art will appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are intended to be within the scope of protection of this application.

Claims

1. A battery cell, the volume of which is greater than or equal to 3000 cm 3 The shell is a right parallelepiped, the shell includes a shell and two end covers, the shell includes a first wall, a second wall, a third wall and a fourth wall formed in one piece, the first wall and the second wall are arranged opposite to each other along a first direction, the third wall and the fourth wall are arranged opposite to each other along a second direction, the shell has two openings arranged opposite to each other along a third direction, the two end covers are respectively covered with the openings on the corresponding sides, the end covers are welded to the shell, the first direction, the second direction and the third direction are perpendicular to each other, and it is characterized in that The battery cell comprises: An electrode terminal, disposed on the end cap; at least one electrode assembly, the electrode assembly being accommodated in the housing, the electrode assembly comprising a main body and a tab extending from the main body, the tab being electrically connected to the electrode terminal; an electrolyte contained in the housing; Among them, the size of the shell in the first direction is W1, the size of the shell in the second direction is T1, the size of the shell in the third direction is H1, the sum of the thickness of the first wall and the second wall is a, the sum of the thickness of the third wall and the fourth wall is b, and the sum of the thickness of the two end covers is c, satisfying: (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥90%, 40mm≤T1≤150mm, 120mm≤H1≤400mm, 150mm≤W1≤1500mm.

2. The battery cell according to claim 1, characterized in that: (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥92%, optionally, (W1-a)*(T1-b)*(H1-c) / (W1*T1*H1)≥95%.

3. The battery cell according to claim 1 or 2, characterized in that: (W1-a) / W1≥97.0%, (T1-b) / T1≥96.5%, and (H1-c) / H1≥96.5%.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The battery cell further includes a third insulating member and a fourth insulating member, wherein the third insulating member is disposed between one of the end caps and the electrode assembly and abuts against the end cap; the fourth insulating member is disposed between the other end cap and the electrode assembly and abuts against the end cap; The maximum dimension of the third insulating part in the third direction is d3, and the maximum dimension of the fourth insulating part in the third direction is d4, satisfying: (W1-a-1.6mm)*(T1-b-1.6mm)*(H1-c-d3-d4) / (W1*T1*H1)≥88%, 2mm≤d3≤10mm, and 2mm≤d4≤10mm.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The battery cell further includes a third insulating member and a fourth insulating member, wherein the third insulating member is disposed between one of the end caps and the electrode assembly and abuts against the end cap; the fourth insulating member is disposed between the other end cap and the electrode assembly and abuts against the end cap; The maximum dimension of the third insulating part in the third direction is d3, and the maximum dimension of the fourth insulating part in the third direction is d4, satisfying: (W1-a-4mm)*(T1-b-4mm)*(H1-c-d3-d4) / (W1*T1*H1)≥85%, 2mm≤d3≤10mm, and 2mm≤d4≤10mm.

6. The battery cell according to claim 1, characterized in that: W1*T1*H1≤40000cm 3 。 7. The battery cell according to claim 6, characterized in that: 3200cm 3 ≤W1*T1*H1≤32000cm 3 。 8. The battery cell according to claim 7, characterized in that: 3720cm 3 ≤W1*T1*H1≤12500cm 3 。 9. The battery cell according to claim 8, characterized in that: 4000cm 3 ≤W1*T1*H1≤6000cm 3 。 10. The battery cell according to any one of claims 1 to 9, characterized in that: The main body is flat; The number of the electrode assembly is one, the maximum dimension of the main body in the first direction is W2, the maximum dimension of the main body in the second direction is T2, and the maximum dimension of the main body in the third direction is H2, satisfying: (W2*T2*H2) / (W1*T1*H1)≥80%; Or, there are multiple electrode assemblies, and the maximum size of the whole composed of the main bodies of the multiple electrode assemblies in the first direction is W2, the maximum size of the whole composed of the main bodies of the multiple electrode assemblies in the second direction is T2, and the maximum size of the whole composed of the main bodies of the multiple electrode assemblies in the third direction is H2, satisfying: (W2*T2*H2) / (W1*T1*H1)≥80%.

11. The battery cell according to claim 10, characterized in that: W2 / (W1-a)≥91.5%, T2 / (T1-b)≥93.2%, and H2 / (H1-c)≥94.0%.

12. The battery cell according to claim 10 or 11, characterized in that: The electrode assembly is a winding structure, the main body includes a straight area, a first bending area and a second bending area, and along the first direction, the first bending area and the second bending area are respectively located at two ends of the straight area; The first bending zone includes a plurality of first bending portions stacked in layers, and along the first direction, a distance between an inner vertex of an innermost first bending portion and an outer vertex of an outermost first bending portion among the plurality of first bending portions is W3; The second bending zone includes a plurality of second bending portions stacked in layers, and along the first direction, a distance between an inner vertex of the innermost second bending portion and an outer vertex of the outermost second bending portion among the plurality of second bending portions is W4; Satisfies: (W3+W4) / W2≤30%.

13. The battery cell according to any one of claims 1 to 12, characterized in that: The material of the first wall, the second wall, the third wall, the fourth wall and the end cover all includes aluminum alloy, and the aluminum alloy includes the following components in mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

14. The battery cell according to any one of claims 1 to 13, characterized in that: The thickness of the first wall and the second wall are both a1, the thickness of the third wall and the fourth wall are both b1, and the thickness of the two end covers are c1 and c2 respectively, satisfying: c2=c1, c1>a1, c1>b1.

15. The battery cell according to claim 14, characterized in that: 0.5mm≤a1≤1.5mm, 0.8≤b1≤1.5mm, 1.5mm≤c2≤4mm.

16. The battery cell according to claim 15, characterized in that: 2.5mm≤c2≤4mm.

17. The battery cell according to any one of claims 14 to 16, characterized in that: (W1-2*a1)*(T1-2*b1)*(H1-2*c1) / (W1*T1*H1)≥95%.

18. The battery cell according to any one of claims 1 to 17, characterized in that: T1<W1, T1<H1.

19. The battery cell according to any one of claims 1 to 18, characterized in that: 2≤W1 / T1≤10, and / or, 2≤H1 / T1≤10, and / or, 0.7≤W1 / H1≤1.

6.

20. The battery cell according to any one of claims 1 to 19, characterized in that: The positive electrode material of the battery cell includes lithium phosphate, and the capacity of the battery cell is C, which satisfies: C≥350Ah, C / ((W1-a)*(T1-b)*(H1-c))≥118Ah / L.

21. The battery cell according to any one of claims 1 to 19, characterized in that: The positive electrode material of the battery cell includes a lithium transition metal oxide, and the capacity of the battery cell is C, satisfying: C≥650Ah, C / ((W1-a)*(T1-b)*(H1-c))≥190Ah / L.

22. The battery cell according to any one of claims 1 to 19, characterized in that: The battery cell is a sodium ion battery, and the capacity of the battery cell is C, satisfying: C≥260Ah, C / ((W1-a)*(T1-b)*(H1-c))≥87Ah / L.

23. A battery, characterized in that: Comprising a battery cell as claimed in any one of claims 1 to 22.

24. An electrical device, characterized in that: The battery as claimed in claim 23 is used to provide electrical energy to the electrical device.

25. An energy storage device, characterized in that: include: An energy storage box, wherein the energy storage box has a battery compartment; A plurality of battery cells as described in any one of claims 1-22, wherein the plurality of battery cells are arranged in the battery compartment.

26. The energy storage device according to claim 25, characterized in that: The sum of the volumes of the outer shells of the plurality of battery cells is V1, and the volume of the battery compartment is V2, satisfying: 0.5≤V1 / V2≤0.95.

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