CN220652145U

CN220652145U - Battery monomer, battery, power utilization device and energy storage device

Info

Publication number: CN220652145U
Application number: CN202321602396.8U
Authority: CN
Inventors: 金海族; 刘贺洋; 刘江; 杨丽美; 杨瑞
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-06-21
Filing date: 2023-06-21
Publication date: 2024-03-22
Anticipated expiration: 2033-06-21

Abstract

The embodiment of the application providesA battery cell, a battery, an electricity-using device and an energy-storing device are provided. The battery cell comprises a shell and an electrode assembly, wherein the electrode assembly is accommodated in the shell, the shell is cylindrical, and the height of the shell is H ₁ The radius of the shell is R ₁ The method comprises the steps of carrying out a first treatment on the surface of the The shell comprises a first end wall, a second end wall and a side wall, wherein the first end wall and the second end wall are oppositely arranged along the height direction of the shell, the side wall is connected with the first end wall and the second end wall, the sum of the thicknesses of the first end wall and the second end wall is a, the thickness of the side wall is b, and the requirements are met: (R) ₁ ‑b) ² *(H ₁ ‑a)/(R ₁ ² *H ₁ ) More than or equal to 96 percent. In this way, the volumetric energy density of the cell can be increased under the same chemical material system.

Description

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

Technical Field

The application relates to the technical field of batteries, in particular to a battery monomer, a battery, an electricity utilization device and an energy storage device.

Background

With the development of new energy technology, the battery is increasingly widely applied, for example, to mobile phones, notebook computers, battery cars, electric automobiles, energy storage devices, electric airplanes, electric ships, electric toy automobiles, electric toy ships, electric toy airplanes, electric tools and the like.

In the development of battery technology, how to increase the volumetric energy density of a battery cell is a problem to be solved in battery technology.

Disclosure of Invention

The embodiment of the application provides a battery monomer, battery, power utilization device and energy storage device, can effectively improve the volumetric energy density of battery monomer.

In a first aspect, embodiments of the present application provide a battery cell including a housing and an electrode assembly, the electrode assembly being housed in the housing, the housing being cylindrical, the housing having a height H ₁ The radius of the shell is R ₁ The method comprises the steps of carrying out a first treatment on the surface of the The shell comprises a first end wall, a second end wall and a side wall, wherein the first end wall and the second end wall are oppositely arranged along the height direction of the shell, the side wall is connected with the first end wall and the second end wall, and the first end wall and the side wall are connected with each otherThe sum of the thicknesses of the second end walls is a, the thickness of the side walls is b, and the following conditions are satisfied: (R) ₁ -b) ² *(H ₁ -a)/(R ₁ ² *H ₁ )≥96％。

In the technical scheme, the ratio of the volume of the shell of the battery monomer to the volume of the shell is set to be more than 96%, so that the inner space of the shell is enlarged, the interior of the shell can accommodate larger electrode assemblies and more electrolyte, and the volume energy density of the battery monomer can be improved under the same chemical material system.

In some embodiments, (R) ₁ -b)/R ₁ More than or equal to 99 percent, and R is more than or equal to 100mm ₁ 400mm or more, 0.2mm or less and b or less than 2mm or less. Thus, the size ratio of the inner space of the shell in the radial direction of the shell can be increased, and the volume energy density of the battery cell can be further increased.

In some embodiments, (H) ₁ -a)/H ₁ More than or equal to 96 percent and less than or equal to 100mm of H ₁ 400mm or more, 2mm or less and a or less than 7mm or less. Thus, the size ratio of the inner space of the shell in the height direction of the shell can be increased, and the volume energy density of the battery cell can be further increased.

In some embodiments, the housing comprises a shell and two end caps, wherein the shell is provided with two openings which are oppositely arranged, and the two end caps respectively cover the corresponding openings; the shell is the side wall, and the two end covers are the first end wall and the second end wall respectively.

In some embodiments, the battery cell further comprises a first insulator disposed between and in abutment with the first end wall and the electrode assembly; the second insulating piece is arranged between the second end wall and the electrode assembly and is abutted against the second end wall; the maximum dimension of the first insulating member in the height direction is d ₁ The maximum dimension of the second insulating member in the height direction is d ₂ The method comprises the following steps: (H) ₁ -a-d ₁ -d ₂ )/H ₁ ≥90％，2mm≤d ₁ Not more than 6mm and not more than 2mm d ₂ Is less than or equal to 6mm. Thus, in the height directionAs above, the space left for the electrode assembly by the inside of the case becomes larger, allowing for placement of a higher electrode assembly, so that the volumetric energy density of the battery cell is further improved.

In some embodiments, the housing includes a shell having an opening and an end cap covering the opening; the housing includes an integrally formed second end wall and side wall, and the end cap is the first end wall.

In some embodiments, the battery cell further comprises a third insulator disposed between and in abutment with the first end wall and the electrode assembly; alternatively, the third insulator is disposed between the second end wall and the electrode assembly and abuts against the second end wall; the maximum dimension of the third insulating member in the height direction is d ₃ The method comprises the following steps: (H) ₁ -a-d ₃ )/H ₁ More than or equal to 92 percent, and the diameter of the steel plate is more than or equal to 2mm and less than or equal to d ₃ Is less than or equal to 6mm. In this way, the space left for the electrode assembly inside the case becomes large in the height direction, allowing a higher electrode assembly to be placed, so that the volumetric energy density of the battery cell is further improved.

In some embodiments, 0.001m ³ ≤π*R ₁ ² *H ₁ ≤0.015m ³ . Therefore, on one hand, when the ratio of the volume of the shell to the volume is more than 96%, the wall thickness of the shell is not too small, so that the requirements on the structural strength and the rigidity of the shell can be met; on the other hand, the capacity and the current of the battery monomer can be controlled in a proper range, the heating value of the battery monomer is reduced, and the risk of damage to components in a circuit is reduced.

In some embodiments, the electrode assembly is a coiled structure, the electrode assembly is a cylinder, and the height of the electrode assembly is H ₂ The radius of the electrode assembly is R ₂ The method comprises the following steps: (R) ₂ ² *H ₂ )/(R ₁ ² *H ₁ ) More than or equal to 85 percent. Thus, the electrode assembly can fully utilize the internal space of the housing, the large volume of the housing can not appear, and the small volume of the electrode assemblyAnd (3) improving the volume energy density of the battery cell and reducing the movement of the electrode assembly in the shell.

In some embodiments, R ₂ /(R ₁ -b) is not less than 97.5%, and H ₂ /(H ₁ -a)≥92.5％。

In some embodiments, the materials of the first end wall, the second end wall and the side wall all comprise aluminum alloy, and the aluminum alloy comprises the following components in percentage by mass: 96.7% or more of aluminum, 0.05% or less of copper or less of 0.2% or less of iron or less of 0.7% or less of manganese or less of 1.5% or less of silicon or less of 0.6% or less of zinc or less of 0.1% or less of other single element components or less of 0.05% or less of other element total components or less of 0.15% or less. Therefore, the aluminum alloy with higher strength can be obtained, and the aluminum alloy is used as the material of the shell, so that the impact resistance of the shell can be obviously improved, and the reliability of the battery cell can be improved.

In some embodiments, the materials of the first end wall, the second end wall and the side wall all comprise iron alloy, and the iron alloy comprises the following components in percentage by mass: iron is more than or equal to 98 percent, carbon is more than or equal to 0.15 percent and less than or equal to 2 percent; the alloy also contains manganese, silicon, sulfur, phosphorus and the like, wherein the content of single element is less than or equal to 0.05 percent, and the total content is less than or equal to 0.2 percent. Therefore, the iron alloy with higher strength can be obtained, and the iron alloy is used as the material of the shell, so that the impact resistance of the shell can be obviously improved, and the reliability of the battery cell can be improved.

In some embodiments, the housing comprises a shell having an opening and an end cap that covers the opening, the end cap being welded or crimped to the shell; the shell comprises the second end wall and the side wall which are integrally formed, and the end cover is the first end wall; the battery cell also comprises a positive electrode terminal, the positive electrode terminal is arranged on the second end wall in an insulating mode, the electrode assembly comprises a positive electrode lug and a negative electrode lug, the positive electrode lug is electrically connected with the positive electrode terminal, and the negative electrode lug is electrically connected with the second end wall.

In some embodiments, the housing comprises a shell having an opening and an end cap that covers the opening, the end cap being welded or crimped to the shell; the shell comprises the second end wall and the side wall which are integrally formed, and the end cover is the first end wall; the battery cell also comprises a positive electrode terminal, the positive electrode terminal is arranged on the first end wall in an insulating mode, the electrode assembly comprises a positive electrode lug and a negative electrode lug, the positive electrode lug is electrically connected with the positive electrode terminal, and the negative electrode lug is electrically connected with the first end wall.

In some embodiments, the first end wall has a maximum thickness a ₁ The maximum thickness of the second end wall is a ₂ The method comprises the following steps: a, a ₁ ≥a ₂ ，a ₁ ≥b。

In some embodiments, 1 mm.ltoreq.a ₁ ≤2mm，0.5mm≤a ₂ ≤1.5mm，0.2mm≤b≤0.8mm。

In some embodiments, the housing comprises a shell and two end caps, wherein the shell is provided with two openings which are oppositely arranged, and the two end caps respectively cover the corresponding openings; the shell is the side wall, the two end covers are the first end wall and the second end wall respectively, and the end covers are welded or sealed with the shell; the battery cell also comprises a positive electrode terminal and a negative electrode terminal, wherein the positive electrode terminal is arranged on the first end wall, the negative electrode terminal is arranged on the second end wall, the electrode assembly comprises a positive electrode lug and a negative electrode lug, the positive electrode lug is electrically connected with the positive electrode terminal, and the negative electrode lug is electrically connected with the negative electrode terminal.

In some embodiments, the first end wall has a maximum thickness a ₁ The maximum thickness of the second end wall is a ₂ The method comprises the following steps: a, a ₁ ＝a ₂ ，a ₁ ≥b。

In some embodiments, 1 mm.ltoreq.a ₁ ≤2mm，0.2mm≤b≤1mm。

In some embodiments, 0.3R ₁ /H ₁ ≤4，100mm≤R ₁ ≤400mm，100mm≤H ₁ ≤400mm。

In some embodiments, the positive electrode material of the battery cell comprises lithium-containing phosphate, the capacity of the battery cell C, satisfy: c is larger than or equal to 350Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]≥120Ah/L。

In some embodiments, the positive electrode material of the battery cell comprises a lithium transition metal oxide, and the battery cell has a capacity of C that satisfies: c is greater than or equal to 650Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]≥193Ah/L。

In some embodiments, the battery cell is a sodium ion battery, the capacity of the battery cell is C, satisfying: c is greater than or equal to 260Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]≥88Ah/L。

In a second aspect, embodiments of the present application provide a battery, including a battery box and a battery unit provided in any one of the embodiments of the first aspect, where the battery unit is accommodated in the battery box.

In a third aspect, embodiments of the present application provide an electrical device, including a battery provided in any one of the embodiments of the second aspect.

In a fourth aspect, embodiments of the present application provide an energy storage device, including an energy storage box and a plurality of battery cells provided by any one embodiment of the first aspect, the energy storage box includes a battery compartment, and a plurality of battery cells are accommodated in the battery compartment.

In some embodiments, the battery cell includes an electrode terminal disposed on the housing, the sum of volumes of the housings of the plurality of battery cells being V ₁ The volume of the battery compartment is V ₂ The method comprises the following steps: v is more than or equal to 0.5 ₁ /V ₂ Less than or equal to 0.95. In this way, the space utilization of the energy storage device can be improved, more battery cells are arranged in the battery compartment of the energy storage box body, namely more energy supply structures are arranged in the unit space, so that the energy density can be improved, and the capacity can be improved without enlarging the occupied space.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

FIG. 2 is an exploded view of a battery provided in some embodiments of the present application;

fig. 3 is a schematic structural diagram of an energy storage device according to some embodiments of the present disclosure;

FIG. 4 is a schematic diagram illustrating an internal structure of the energy storage device shown in FIG. 3;

fig. 5 is a schematic structural diagram of a battery cell according to some embodiments of the present disclosure;

fig. 6 is an exploded view of the battery cell shown in fig. 5;

Fig. 7 is a cross-sectional exploded view of the battery cell shown in fig. 5;

fig. 8 is a schematic structural diagram of a battery cell according to other embodiments of the present disclosure;

fig. 9 is an exploded view of the battery cell shown in fig. 8.

Fig. 10 is a cross-sectional exploded view of the battery cell shown in fig. 8;

fig. 11 is an exploded view of a battery cell provided in accordance with further embodiments of the present application;

fig. 12 is an exploded view of the battery cell shown in fig. 11;

fig. 13 is a cross-sectional view of the battery cell shown in fig. 11;

fig. 14 is a cross-sectional exploded view of the battery cell shown in fig. 11.

Icon: 1-a housing; 11-a housing; 12-end caps; 101-a first end wall; 102-a second end wall; 103-sidewalls; a 2-electrode assembly; 21-a body; 22-positive electrode lugs; 23-negative electrode ear; 31-positive electrode terminal; 32-a negative electrode terminal; 41-a first insulating member; 42-a second insulator; 43-a third insulator; 44-fourth insulator; 51-a first current collecting member; 52-a second current collecting member; 10-battery cell; 20-a battery box; 201-a first part; 202-a second part; 100-cell; 200-a controller; 300-motor; 400-an energy storage box body; 401-battery compartment; 402-an electrical bin; 403-upright posts; 404-battery carrier; 1000-vehicle; 2000-energy storage device; x-height direction.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions. The terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means 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 appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the embodiments of the present application, the same reference numerals denote the same components, and in the interest of brevity, detailed descriptions of the same components are omitted in different embodiments. The term "plurality" as used herein refers to more than two (including two).

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited by the embodiment of the present application.

Reference to a battery in embodiments of the present 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 the present application may include a battery module or a battery pack, or the like. The battery generally includes a battery case for enclosing one or more battery cells. The battery box body can avoid that liquid or other foreign matters influence the charging or discharging of the battery monomers.

The battery cell includes a case, an electrode assembly, and an electrolyte, the case being configured to house the electrode assembly and the electrolyte. The electrode assembly consists of a positive plate, a negative plate and a separation film. The battery cell mainly relies on metal ions to move between the positive and negative electrode plates to operate. The positive plate comprises a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer is coated on the surface of the positive electrode current collector, the positive electrode current collector without the positive electrode active material layer protrudes out of the positive electrode current collector coated with the positive electrode active material layer, and the positive electrode current collector without the positive electrode active material layer is used as a positive electrode lug. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate or the like. The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is coated on the surface of the negative electrode current collector, the negative electrode current collector without the negative electrode active material layer protrudes out of the negative electrode current collector coated with the negative electrode active material layer, and the negative electrode current collector without the negative electrode active material layer is used as a negative electrode lug. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. The material of the separator may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may be a wound structure or a lamination structure, and the embodiment of the present application is not limited thereto.

The battery cell may further include an electrode terminal disposed on the case, the electrode terminal being electrically connected with the tab of the electrode assembly to output electric energy of the battery cell. The electrode terminal and the tab may be directly connected, for example, the electrode terminal and the tab may be directly welded. The electrode terminal and the tab may be indirectly connected, for example, by a current collecting member. The current collecting member may be a metal conductor such as copper, iron, aluminum, steel, aluminum alloy, or the like.

The development of battery technology is to consider various design factors, such as safety, cycle life, discharge capacity, and charge-discharge rate. In addition, the volumetric energy density is also an important parameter for evaluating the performance of the battery.

In the battery cell, in order to improve safety, the risk of the casing breaking when the battery cell is subjected to an external impact or when the internal pressure of the battery cell is large is reduced, and the casing is generally designed to be thick. However, a thicker housing may result in a reduced housing interior space. In addition, in order to reduce the possibility of internal short circuit of the battery cell, insulation members are generally arranged inside the casing, and the insulation members inevitably occupy a part of space, so that the space reserved for the electrode assembly is very limited, and the volumetric energy density of the battery cell is low.

In view of this, the present embodiments provide a cylindrical battery cell in which the ratio of the volume of the case to the volume of the case is 96% or more, thereby making the inner space of the case large to accommodate a larger electrode assembly and more electrolyte, and the volumetric energy density of the battery cell can be improved under the same chemical material system.

The battery cell described in the embodiments of the present application is suitable for a battery and an electric device using the battery.

The electric device may be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, or the like. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle; spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the electric toy includes fixed or mobile electric toys, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others. The embodiment of the application does not limit the electric device in particular.

For convenience of explanation, the following examples will be described taking an electric device as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present application. The battery 100 is provided in the interior of the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may be used as an operating power source of the vehicle 1000.

The vehicle 1000 may also include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to power the motor 300, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1000.

In some embodiments of the present application, battery 100 may not only serve as an operating power source for vehicle 1000, but may also serve as a driving power source for vehicle 1000, instead of or in part instead of fuel oil or natural gas, to provide driving power for vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to some embodiments of the present application. The battery 100 includes a battery cell 10 and a battery case 20, and the battery cell 10 is accommodated in the battery case 20.

The battery box 20 is a component for accommodating the battery cell 10, the battery box 20 provides an accommodating space for the battery cell 10, and the battery box 20 can adopt various structures. In some embodiments, the battery case 20 may include a first portion 201 and a second portion 202, the first portion 201 and the second portion 202 being overlapped with each other to define a receiving space for receiving the battery cell 10. The first portion 201 and the second portion 202 may be of various shapes, such as a rectangular parallelepiped, a cylinder, etc. The first portion 201 may be a hollow structure with one side opened, and the second portion 202 may be a hollow structure with one side opened, and the open side of the second portion 202 is closed to the open side of the first portion 201, so as to form the battery case 20 having the accommodating space. The first portion 201 may be a hollow structure with one side open, the second portion 202 may be a plate-like structure, and the second portion 202 may be covered on the open side of the first portion 201 to form the battery case 20 having the accommodation space. The first portion 201 and the second portion 202 may be sealed by a sealing element, which may be a sealing ring, a sealant, or the like.

In the battery 100, the number of the battery cells 10 may be one or a plurality. If there are multiple battery cells 10, the multiple battery cells 10 may be connected in series or parallel or a series-parallel connection, where a series-parallel connection refers to that there are both series connection and parallel connection among the multiple battery cells 10. The plurality of battery cells 10 may be connected in series or parallel or in series-parallel to form a battery module, and the plurality of battery modules are connected in series or parallel or in series-parallel to form a whole and are accommodated in the battery case 20. All the battery cells 10 may be directly connected in series, parallel or series-parallel, and then the whole body formed by all the battery cells 10 is accommodated in the battery box 20.

In some embodiments, the battery 100 may further include a bus bar (not shown), through which the plurality of battery cells 10 may be electrically connected to each other, so as to realize serial connection, parallel connection, or series-parallel connection of the plurality of battery cells 10. The bus member may be a metal conductor such as copper, iron, aluminum, stainless steel, aluminum alloy, or the like.

The battery cell described in the embodiments of the present application is also applicable to an energy storage device.

The role of energy storage devices in future energy application scenarios is increasingly highlighted. On the one hand, in the new energy power generation, wind energy and solar energy power generation have the characteristics of intermittence and instability, and the energy storage device is introduced to effectively inhibit the fluctuation of the generated power, so that the electric energy quality is improved. On the other hand, the energy storage device can also "peak clipping and valley filling", namely, the redundant power of the power grid is absorbed when the power grid is in the low valley period of the output power, and then the power grid is actively supplied with power when the power grid is in the peak period of the output power, so that the peak power of the power grid can be greatly reduced, the management capacity of the power demand side is improved, the application of renewable energy sources is promoted, and the like.

Referring to fig. 3 and fig. 4, fig. 3 is a schematic structural diagram of an energy storage device 2000 according to some embodiments of the present application, and fig. 4 is a schematic structural diagram of an energy storage device 2000 shown in fig. 3.

The energy storage device 2000 includes an energy storage box 400, a battery 100, and a control module (not shown), wherein an internal space of the energy storage box 400 is divided into a battery compartment 401 and an electrical compartment 402, the battery 100 is placed in the battery compartment 401, and the control module is placed in the electrical compartment 402. The battery compartment 401 is provided therein with a pillar 403 and a battery bracket 404, the pillar 403 is generally disposed along a height direction of the energy storage case 400, the battery bracket 404 is fixed to the pillar 403, and the battery 101 is placed on the battery bracket 404 so that the plurality of batteries 100 are arranged in the battery compartment 401. Of course, in other embodiments, the battery unit 10 may be directly placed in the battery compartment 401, without placing the battery unit 10 in the battery box 20 first, and then placing the battery box 20 in the battery compartment 401, so that the stand column 403 and the battery bracket 404 are not required to be disposed in the battery compartment 401, which improves the energy density of the energy storage device 2000.

Referring to fig. 5 to 7, fig. 5 is a schematic structural diagram of a battery cell 10 according to some embodiments of the present disclosure, fig. 6 is an exploded view of the battery cell 10 shown in fig. 5, and fig. 7 is a cross-sectional exploded view of the battery cell shown in fig. 5.

The battery cell 10 may include a case 1 and an electrode assembly 2.

The case 1 is a member for accommodating the electrode assembly 2, the case 1 has a cylindrical shape, and the height of the case 1 is H ₁ The radius of the shell 1 is R ₁ . The height direction X of the housing 1 refers to the axial direction of the housing 1.

The electrode assembly 2 may be one or more. When the electrode assemblies 2 are plural, the plural electrode assemblies 2 may be arranged in the height direction X of the case 1.

The electrode assembly 2 is a component in which 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.

Referring to fig. 6 and 7, the case 1 includes first and second end walls 101 and 102 disposed opposite to each other in a height direction X, and a side wall 103 connecting the first and second end walls 101 and 102, the side wall 103 being disposed around the first end wall 101 and around the second end wall 102, the side wall 103, the first and second end walls 101 and 102 together enclosing a space accommodating the electrode assembly 2.

Wherein the sum of the thicknesses of the first end wall 101 and the second end wall 102 is a, and the thickness of the side wall 103 is b, satisfying: (R) ₁ -b) ² *(H ₁ -a)/(R ₁ ² *H ₁ )≥96％。

In this embodiment, the thicknesses of the first end wall 101 and the second end wall 102 may be equal or different.

As a and b are both greater than 0, it is understood that 96% to less (R ₁ -b) ² *(H ₁ -a)/(R ₁ ² *H ₁ )＜100％。

(R ₁ -b) ² *(H ₁ -a)/(R ₁ ² *H ₁ ) Any value between 96% and 100% is possible, for example, 96%, 96.5%, 97, 97.5%, 98%, 98.5%, 99%, 99.5%, etc.

Wherein pi (R ₁ -b) ² *(H ₁ A) is understood to be the volume of the housing 1, i.e. the volume of the space enclosed by the inner surface of the housing 1; pi R ₁ 2*H ₁ The volume of the case 1 is approximately equal to the volume of the battery cell 10. Pi is the circumference ratio.

If the outer surface of the first end wall 101 and the outer surface of the second end wall 102 are both planar, H is measured with respect to the outer surface of the first end wall 101 and the outer surface of the second end wall 102 ₁ . For example, if the outer surface of first end wall 101 and the outer surface of second end wall 102 are both planar, then H ₁ To be in the height direction X, the distance between the outer surface of the first end wall 101 and the outer surface of the second end wall 102.

If the outer surface of the first end wall 101 or the outer surface of the second end wall 102 is formed with a convex portion or a concave portion, H is measured with reference to a planar area of the outer surface (i.e., an area other than the convex portion or the concave portion) ₁ . For example, if the outer surface of the first end wall 101 is planar and the outer surface of the second end wall 102 is formed with a first protrusion, H ₁ To be along the height direction X, a second endThe distance between the planar area of the outer surface of the wall 102 other than the first protrusion and the outer surface of the first end wall 101. If the outer surface of the second end wall 102 is formed with a first protrusion and the outer surface of the first end wall 101 is formed with a second protrusion, H ₁ To be along the height direction X of the battery cell 10, the distance between the planar area of the outer surface of the first end wall 101 excluding the second convex portion and the planar area of the outer surface of the second end wall 102 excluding the first convex portion.

If the first end wall 101, the second end wall 102 and the side wall 103 are walls 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, thereby obtaining the thickness of the wall.

If one of the first end wall 101, the second end wall 102 and the side wall 103 is a wall having an uneven thickness, the distance between the outer surface and the inner surface of the wall is measured from the position where the thickness of the wall is largest, thereby obtaining the thickness of the wall. That is, if the thickness of a certain wall is not uniform, a or b is calculated by taking the maximum thickness of the wall.

In the embodiment, the ratio of the volume of the shell 1 of the battery cell 10 to the volume of the shell 1 is set to be more than 96%, so that the inner space of the shell 1 is enlarged, and the larger electrode assembly 2 can be accommodated; the volumetric energy density of the cell 10 can be increased under the same chemical material system.

In order to make the ratio of the volume of the housing 1 to the volume of the housing 1 be 96% or more and to make the ratio of the wall thickness of the housing 1 in the height direction X and the radial direction uniform, the stress balance of the housing 1 in each direction is improved. In some embodiments, R ₁ And b satisfies (R) ₁ -b)/R ₁ More than or equal to 99.0 percent and less than or equal to 100mm R ₁ ≤400mm，0.2mm≤b≤2mm。

By combining R ₁ -b and R ₁ The ratio of (2) is set to 99.0% or more so that the radius of the inner space of the case 1 becomes large in the case where the radius of the case 1 is not changed, so that the electrode assembly 2 having a larger radius can be accommodated; the volumetric energy density of the cell 10 can be increased under the same chemical material system.

(R ₁ -b)/R ₁ Any value between 99.0% and 100% is possible, for example, 99.0%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, etc.

R ₁ May be any value between 100mm and 400mm, for example, 100mm, 120mm, 140mm, 160mm, 180mm, 200mm, 250mm, 300mm, 350mm, 400mm, etc.

b may be any value between 0.2mm and 2mm, for example 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm.

In some embodiments, H ₁ And a satisfies (H) ₁ -a)/H ₁ More than or equal to 96 percent and less than or equal to 100mm of H ₁ ≤400mm，2mm≤a≤7mm。

By combining H ₁ -a and H ₁ The ratio of (2) is set to 96% or more so that the height of the inner space of the case 1 becomes large in the case where the height of the battery cell 10 is not changed, thereby allowing the higher electrode assembly 2 to be accommodated; the volumetric energy density of the cell 10 can be increased under the same chemical material system.

(H ₁ -a)/H ₁ Any value between 96% and 100% is possible, for example, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.5%, etc.

H ₁ May be any value between 100mm and 400mm, for example, 100mm, 120mm, 140mm, 160mm, 180mm, 200mm, 250mm, 300mm, 350mm, 400mm, etc.

a may be any value between 2mm and 7mm, for example, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, etc.

As an example, the housing 1 may include a case 11 and an end cap 12.

The housing 11 may be a hollow structure having one end formed with an opening and the other end closed, or the housing 11 may be a hollow structure having opposite ends formed with an opening. The opening is for the electrode assembly 2 to enter the interior space of the housing 11. The end cap 12 is a member closing the opening of the case 11 to isolate the inner environment of the battery cell 10 from the outer environment. The end cap 12 defines a sealed space together with the case 11 for accommodating the electrode assembly 22, the electrolyte, and other components. The end cap 12 may be attached to the housing 11 by welding or crimping to close the opening of the housing 11. The shape of the end cap 12 may be adapted to the shape of the housing 11, for example, the housing 11 has a cylindrical structure, and the end cap 12 has a circular plate-like structure adapted to the housing 11.

In the battery cell 10, the end caps 12 may be one or two.

As shown in fig. 6, 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 correspondingly, the two end caps 12 respectively close 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 side wall 103 serves as the housing 11, the first end wall 101 serves as one end cap 12, and the second end wall 102 serves as the other end cap 12.

As shown in fig. 9 and 12, in the embodiment in which the housing 11 is a hollow structure having an opening formed at one end, one end cap 12 may be provided corresponding to the end cap 12, the opening of one end of the housing 11 is closed by the end cap 12, and a sealed space is defined by the end cap 12 and the housing 11. In these embodiments, the second end wall 102 and the side wall 103 are integrally formed and serve as the housing 11, the first end wall 101 is formed separately from the side wall 103, and the first end wall 101 serves as the end cap 12.

In order to reduce the possibility of an internal short circuit of the battery cell 10, an insulating member may be provided inside the case 1, but the insulating member inevitably occupies a part of the inner space of the case 1, resulting in a reduction in the space reserved for the electrode assembly 2.

Referring to fig. 6 and 7, 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 disposed opposite to each other along a height direction X, and the two end caps 12 respectively cover the openings on the corresponding sides; the housing 11 is a side wall 103, and the two end caps 12 are a first end wall 101 and a second end wall 102 respectively; the battery cell 10 further includes a first insulator 41 and a second insulator 42, the first insulator 41 being disposed between the first end wall 101 and the electrode assembly 2 and abutting against the first end wall 101; the second insulator 42 is provided between the second end wall 102 and the electrode assembly 2, and abuts against the second end wall 102; first one The maximum dimension of the insulating member 41 in the height direction X is d ₁ The second insulating member 42 has a maximum dimension d in the height direction X ₂ The method comprises the following steps: (H) ₁ -a-d ₁ -d ₂ )/H ₁ ≥90％，2mm≤d ₁ Not more than 6mm and not more than 2mm d ₂ ≤6mm。

In this embodiment, the first insulating member 41 and the second insulating member 42 may be lower plastic.

In the present embodiment, H ₁ -a-d ₁ -d ₂ The meaning of the expression is: when the first insulator 41 abutting the first end wall 101 is provided between the first end wall 101 and the electrode assembly 2 and the second insulator 42 abutting the second end wall 102 is provided between the second end wall 102 and the electrode assembly 2, the inner space of the case 1 is left to the maximum size of the electrode assembly 2 in the height direction X.

By combining (H) ₁ -a-d ₁ -d ₂ ) And H ₁ The ratio of (2) is set to 90% or more such that the space left for the electrode assembly 2 inside the case 1 in the height direction X becomes large, allowing the electrode assembly 2 having a greater height to be placed, so that the volumetric energy density of the battery cell 10 is further improved.

Referring to fig. 8 to 14, fig. 8 is a schematic structural diagram of a battery cell according to other embodiments of the present application, fig. 9 is an exploded view of the battery cell shown in fig. 8, fig. 10 is a sectional exploded view of the battery cell shown in fig. 8, fig. 11 is an exploded view of the battery cell according to still other embodiments of the present application, fig. 12 is an exploded view of the battery cell shown in fig. 11, fig. 13 is a sectional exploded view of the battery cell shown in fig. 11, and fig. 14 is a sectional exploded view of the battery cell shown in fig. 11.

In some embodiments of the present application, the housing 1 includes a shell 11 and an end cap 12, the shell 11 having an opening, the end cap 12 covering the opening; the housing 11 includes an integrally formed second end wall 102 and side wall 103, and the end cap 12 is a first end wall 101; the battery cell 10 further includes a third insulating member 43, and in the embodiment shown in fig. 9 and 10, the third insulating member 43 is disposed between the first end wall 101 and the electrode assembly 2, and abuts against the first end wall 101; in the embodiment shown in fig. 13 and 14, the third insulator 43Is disposed between the second end wall 102 and the electrode assembly 2, and abuts against the second end wall 102; the maximum dimension of the third insulating member 43 in the height direction X is d ₃ The method comprises the following steps: (H) ₁ -a-d ₃ )/H ₁ More than or equal to 92 percent, and the diameter of the steel plate is more than or equal to 2mm and less than or equal to d ₃ ≤6mm。

The third insulator 43 may be a lower plastic.

In the present embodiment, H ₁ -a-d ₃ The meaning of the expression is: when the third insulator 43 abutting the first end wall 101 is provided between the first end wall 101 and the electrode assembly 2, or the third insulator 43 abutting the second end wall 102 is provided between the second end wall 102 and the electrode assembly 2, the inner space of the case 1 is left to the maximum size of the electrode assembly 2 in the height direction X.

By combining (H) ₁ -a-d ₃ ) And H ₁ The ratio of (2) is set to 92% or more such that the space left for the electrode assembly 2 inside the case 1 becomes large, allowing the electrode assembly 2 having a greater height to be placed, so that the volumetric energy density of the battery cell 10 is further improved.

In some embodiments of the present application, R ₁ And H ₁ The method meets the following conditions: 0.001m ³ ≤π*R ₁ ² *H ₁ ≤0.015m ³ I.e. the volume of the housing 1 is 0.001m ³ ～0.015m ³ Between them.

When pi is R ₁ ² *H ₁ ＜0.001m ³ In order to make the ratio of the volume of the casing 1 to the volume of the casing 1 at least 96%, the wall thickness of the casing 1 needs to be designed to be small, which results in a small load that the casing 1 can bear, and the casing 1 is not sufficient in structural strength and rigidity, and is easily deformed or broken, which is not good for the safety of the battery cell 10.

When pi is R ₁ ² *H ₁ ＞0.015m ³ In this case, the volume of the battery cell 10 is larger, the capacity is larger, and the current when the battery cell 10 discharges is larger, so that the heat productivity of the overcurrent element in the circuit is larger, and the overcurrent element is easy to damage.

In the present embodiment, the volume of the casing 1 is set at 0.001m ³ ～0.015m ³ On the one hand, when the ratio of the volume of the shell 1 to the volume is more than 96%, the wall thickness of the shell 1 is not too small, so that the requirements on the structural strength and the rigidity of the shell 1 can be met; on the other hand, the capacity and current of the battery cell 10 can be controlled within proper ranges, and the risk of damage to overcurrent elements in the circuit is reduced.

π*R ₁ ² *H ₁ May be 0.001m ³ ～0.015m ³ Arbitrary value in between, e.g. 0.001m ³ 、0.0015m ³ 3、0.002m ³ 、0.003m ³ 、0.004m ³ 、0.005m ³ 、0.006m ³ 、0.007m ³ 、0.008m ³ 、0.009m ³ 、0.01m ³ 、0.011m ³ 、0.012m ³ 、0.013m ³ 、0.014m ³ 、0.015m ³ Etc.

Referring to fig. 7, 10 and 14, in some embodiments of the present application, the electrode assembly 2 is a rolled structure, the electrode assembly 2 is a cylinder, and the height of the electrode assembly 2 is H ₂ The radius of the electrode assembly 2 is R ₂ The method comprises the following steps: (R) ₂ ² *H ₂ )/(R ₁ ² *H ₁ )≥85％。

The electrode assembly 2 is a rolled structure formed by rolling a positive electrode sheet, a separator, and a negative electrode sheet.

The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer coated on a partial region of the positive electrode current collector. The regions of the positive electrode active material layer and the positive electrode current collector coated with the positive electrode active material layer form a positive electrode coating region, the regions of the positive electrode current collector not coated with the positive electrode active position layer form a positive electrode tab 22, and the positive electrode tab 22 protrudes from the positive electrode coating region. The number of the positive electrode tabs 22 may be plural, and the plural positive electrode tabs 22 may be arranged at intervals before the positive electrode sheet is wound, and stacked together after the positive electrode sheet is wound. The number of the positive electrode tabs 22 may be one, and the length of the positive electrode tab 22 is equal to the length of the positive electrode sheet.

The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on a partial region of the negative electrode current collector. The regions of the anode active material layer and the anode current collector coated with the anode active material layer form an anode coating region, and the regions of the anode current collector not coated with the anode active material layer form anode tabs 23, the anode tabs 23 protruding from the anode coating region. The number of the negative electrode tabs 23 may be plural, and the plurality of negative electrode tabs 23 may be arranged at intervals before the negative electrode sheet is wound, and laminated together after the negative electrode sheet is wound. The number of the negative electrode tabs 23 may be one, and the length of the negative electrode tab 23 is equal to the length of the negative electrode sheet.

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 the main body 21 of the electrode assembly 2. The positive electrode tab 22 and the negative electrode tab 23 protrude from the main body 21.

H ₂ Is the height of the electrode assembly 2, that is, the distance between both end surfaces of the electrode assembly 2 in the height direction X. If the end face of the electrode assembly 2 in the height direction X is an uneven surface, the height of the electrode assembly 2 is measured with reference to the most convex point on the end face, i.e., H ₂ Is the largest dimension of the electrode assembly 2 in the height direction X. If a plurality of electrode assemblies 2 arranged in the height direction X are provided in the battery cell 10, H ₂ Is the largest dimension in the height direction X of the whole composed of the plurality of electrode assemblies 2.

R ₂ Is the radius of the electrode assembly 2. If the outer peripheral surface of the electrode assembly 2 is an irregular cylindrical surface, half of the maximum diameter of the cylindrical surface is taken as R in measurement ₂ . If a plurality of electrode assemblies 2 are provided in the battery cell 10, H ₂ Is the largest dimension in the height direction X of the whole composed of the main bodies 21 of the plurality of electrode assemblies 2. If a plurality of electrode assemblies 2 arranged in the height direction X are provided in the battery cell 10, R ₂ Is half of the maximum diameter of the whole composed of the plurality of electrode assemblies 2.

In the present embodiment, the method is performed by combining (R ₂ ² *H ₂ )/(R ₁ ² *H ₁ ) Setting to 85% or more enables the electrode assembly 2 to fully utilize the internal space of the case 1, without the case where the volume of the case 1 is large, while the volume of the electrode assembly 2 is small,the volumetric energy density of the battery cell 10 is increased, and the play of the electrode assembly 2 in the case 1 is reduced.

(R ₂ ² *H ₂ )/(R ₁ ² *H ₁ ) Any value between 85% and 100% is possible, such as 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc.

In order to make R ₂ ² *H ₂ And R is R ₁ ² *H ₁ Can be above 85% and match the dimensions of the electrode assembly 2 in all directions to the dimensions of the interior space of the housing 1 in all directions to further reduce the play of the electrode assembly 2 within the housing 1, in some embodiments, to satisfy: r is R ₂ /(R ₁ -b) is not less than 97.5%, and H ₂ /(H ₁ -a)≥92.5％。

By combining R ₂ And R is ₁ The ratio of b is set to be more than 97.5%, so that the space utilization rate of the inside of the shell 1 in the radial direction can be improved; the volumetric energy density of the cell 10 can be increased under the same chemical material system. R is R ₂ And R is ₁ The ratio of-b may be any value above 97.5%, such as 97.5%, 97.6%, 97.8%, 98.0%, 98.2%, 98.4%, 98.6%, 98.8%, 99.0%, 99.2%, 99.4%, 99.6%, 99.8%, etc.

By combining H ₂ And H ₁ The ratio of a is set to 92.5% or more, so that the space utilization rate of the inside of the housing 1 in the height direction X can be improved; the volumetric energy density of the cell 10 can be increased under the same chemical material system. H ₂ And H ₁ The ratio of-a may be any value above 92.5%, such as 92.5%, 93.0%, 93.5%, 94.0%, 94.5%, 95.0%, 95.5%, 96.0%, 96.5%, 97.0%, 97.5%, 98.0%, 98.5%, etc.

At 0.001m ³ ≤π*R ₁ ² *H ₁ ≤0.015m ³ And (R) ₂ ² *H ₂ )/(R ₁ ² *H ₁ ) More than or equal to 85 percent of the battery monomer 10The volume is large, and the volume of the electrode assembly 2 is also large. The larger the volume of the electrode assembly 2, the greater the mass of the electrode assembly 2 under the same chemical material system. However, when the battery cell 10 falls or collides, the electrode assembly 2 moves in the case 1, and at this time, the impact of the electrode assembly 2 having a larger mass on the case 1 is greater.

In order to enable the walls of the casing 1 to withstand a large impact, reduce the risk of deformation of the casing 1 and improve the reliability of the battery cell 10, in some embodiments of the present application, the materials of the first end wall 101, the second end wall 102 and the side wall 103 all comprise an aluminum alloy, which comprises the following components in percentage by mass: 96.7% or more of aluminum, 0.05% or less of copper or less of 0.2% or less of iron or less of 0.7% or less of manganese or less of 1.5% or less of silicon or less of 0.6% or less of zinc or less of 0.1% or less of other single element components or less of 0.05% or less of other element total components or less of 0.15% or less. By controlling the mass percentages of the various elements in the above-mentioned intervals, an aluminum alloy with higher strength can be obtained, and the adoption of the aluminum alloy as the material of the housing 1 can remarkably improve the impact resistance of the housing 1 and the reliability of the battery cell 10.

In other embodiments of the present application, the materials of the first end wall 101, the second end wall 102 and the side wall 103 all comprise iron alloys, which comprise the following components in percentage by mass: iron is more than or equal to 98 percent, carbon is more than or equal to 0.15 percent and less than or equal to 2 percent; the alloy also contains manganese, silicon, sulfur, phosphorus and the like, wherein the content of single element is less than or equal to 0.05 percent, and the total content is less than or equal to 0.2 percent. By controlling the mass percentages of the various elements in the above-mentioned intervals, a higher-strength iron alloy can be obtained, and the use of the iron alloy as the material of the casing 1 can significantly improve the impact resistance of the casing 1 and the reliability of the battery cell 10.

Referring to fig. 9 and 10, in some embodiments of the present application, a housing 1 includes a shell 11 and an end cap 12, the shell 11 has an opening, the end cap 12 covers the opening, and the end cap 12 is welded or sealed with the shell 11; the second end wall 102 and the side wall 103 are integrally formed and serve as the housing 11, the first end wall 101 is formed separately from the side wall 103, and the first end wall 101 serves as the end cap 12; the battery cell 10 further includes a positive electrode terminal 31, the positive electrode terminal 31 is arranged on the end cover 12 in an insulating manner, the positive electrode tab 22 of the electrode assembly 2 is electrically connected with the positive electrode terminal 31, and the negative electrode tab 23 of the electrode assembly 2 is electrically connected with the end cover 12.

In the embodiment shown in fig. 9 and 10, the battery cell 10 further includes a first current collecting member 51 and a second current collecting member 52, the positive electrode tab 22 is electrically connected to the positive electrode terminal 31 through the first current collecting member 51, and the negative electrode tab 23 is electrically connected to the case 11 through the second current collecting member 52. Since the case 11 and the end cap 12 are electrically connected by welding or by crimping, the negative electrode tab 23 is electrically connected to the end cap 12.

In other embodiments, the positive tab 22 may be directly connected to the positive electrode terminal 31 without providing the first current collecting member 51 to achieve switching; the negative electrode lug 23 can be directly connected with the shell 11 without arranging a second current collecting member 52 to realize switching; the negative electrode tab 12 may also be electrically connected to the end cap 12 by an electrically conductive member (e.g., a wire) that is provided separately from the case 11.

Referring to fig. 12 to 14, in some embodiments of the present application, a housing 1 includes a shell 11 and an end cap 12, the shell 11 has an opening, the end cap 12 covers the opening, and the end cap 12 is welded to the shell 11 or is in a sealed connection (a sealed connection is shown in the drawings); the second end wall 102 and the side wall 103 are integrally formed and serve as the housing 11, the first end wall 101 is formed separately from the side wall 103, and the first end wall 101 serves as the end cap 12; the battery cell 10 further includes a positive electrode terminal 31, the positive electrode terminal 31 is arranged on the second end wall 102 in an insulating manner, the positive electrode tab 22 of the electrode assembly 2 is electrically connected with the positive electrode terminal 31, and the negative electrode tab 23 of the electrode assembly 2 is electrically connected with the second end wall 102.

In the embodiment shown in fig. 12 to 14, the battery cell 10 further includes a first current collecting member 51, a second current collecting member 52, and a fourth insulator 44, the positive tab 22 is electrically connected to the positive electrode terminal 31 through the first current collecting member 51, the negative tab 23 is electrically connected to the side wall 103 through the second current collecting member 52, and the positive electrode terminal 31 and the second end wall 102 are insulated by the fourth insulator 44. Since the side wall 103 and the second end wall 102 are integrally formed, the negative electrode tab 23 is electrically connected to the second end wall 102.

In other embodiments, the positive tab 22 may be directly connected to the positive electrode terminal 31 without providing the first current collecting member 51 to achieve switching; the negative electrode tab 23 can be directly connected to the case 11 without providing the second current collecting member 52 to perform the switching.

In the case where the second end wall 102 and the side wall 103 are integrally provided and the first end wall 101 is the end cap 12 as the housing 11, the maximum thickness of the first end wall 101 is a ₁ The second end wall 102 has a maximum thickness a ₂ The method comprises the following steps: a, a ₁ ≥a ₂ ，a ₁ ≥b。

At 0.001m ³ ≤π*R ₁ ² *H ₁ ≤0.015m ³ And (R) ₂ ² *H ₂ )/(R ₁ ² *H ₁ ) In case of 85% or more, the volume of the battery cell 10 is large and the volume of the electrode assembly 2 is also large. The larger the volume of the electrode assembly 2, the larger the gas yield of the battery cell 10 upon cycling, and the larger the internal gas pressure of the battery cell 10 under the same chemical material system.

In order to reduce the risk of failure of the connection between the end cap 12 and the housing 11 due to an increase in internal air pressure, in the present embodiment, the thickness of the end cap 12 is designed to be thicker so that the maximum thickness of the end cap 12 is equal to or greater than the maximum thickness of the second end wall 102 and equal to or greater than the thickness of the side wall 103 (i.e., a ₁ ≥a ₂ ，a ₁ And b) so as to allow a weld of greater width or thickness to be formed between the end cap 12 and the housing 11 when the end cap 12 and the housing 11 are welded, thereby improving the welding strength and reducing the risk of tearing the weld; when the end cover 12 and the shell 11 are in rolling connection, the strength and the rigidity of a rolling area can be improved, and the reliability of rolling connection is improved. In addition, increasing the thickness of the end cap 12 may reduce the amount of material used and reduce costs as compared to increasing the thickness of the housing 11 in order to form a weld of greater width or thickness or to form a lap seal area of greater strength and rigidity. While increasing the thickness of the housing 11 means at least increasing the thickness of the side wall 103 to which the end cap 12 is attached, the amount of material used is significantly increased and the cost is high.

Integrally formed with the second end wall 102 and the side wall 103 and serving as the housing 11, a first end wall101 as end cap 12, in some embodiments of the present application, 1 mm.ltoreq.a ₁ ≤2mm，0.5mm≤a ₂ ≤1.5mm，0.2mm≤b≤0.8mm。

a ₁ May be any value between 1mm and 2mm, for example, 1.0mm,1.1mm,1.2mm,1.3mm,1.4mm,1.5mm,1.6mm,1.7mm,1.8mm,1.9mm,2.0mm, etc.

When a is ₁ When < 1.0mm, the thickness of the first end wall 101 is too small, and since the thickness of the second end wall 102 and the side wall 103 is smaller or equal than that of the first end wall 101, it is difficult to secure the structural strength of the case 1, and the battery cell 10 is easily deformed; when a is ₁ At > 2.0mm, the thickness of the first end wall 101 is too large, which is disadvantageous in increasing the volumetric energy density of the battery cell 10, and is costly. In this embodiment, a will be ₁ The volume energy density of the battery cell 10 can be ensured while the structural strength of the housing 1 can be ensured by setting the size to be 1 mm-2 mm.

a ₂ May 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.

When the battery cell 10 is used in a state in which the second end wall 102 faces downward, particulate matter (e.g., carbon powder, metal dust, etc.) inside the battery cell 10 may be deposited on the second end wall 102 due to gravity, resulting in corrosion of the second end wall 102. When a is ₂ When the thickness of the second end wall 102 is less than 0.5mm, the residual thickness of the second end wall 102 after long-term corrosion of the particulate matter deposited thereon is less, and the second end wall 102 is difficult to resist the impact of the electrode assembly 2 and is liable to break when the electrode assembly 2 moves in the case 1. When a is ₂ At > 1.5mm, the thickness of the second end wall 102 is too large, which is detrimental to the volumetric energy density of the cell 10, and is costly. In this embodiment, a will be ₂ Being set to 0.5mm to 1.5mm, the capacity of the second end wall 102 against impact can be ensured while the volumetric energy density of the battery cell 10 is ensured.

b may be any value between 0.2mm and 0.8mm, for example, 0.2mm,0.3mm,0.4mm,0.5mm,0.6mm,0.7mm,0.8mm, etc.

When b < 0.2mm, the thickness of the side wall 103 is too small to ensure the structural strength of the case 1 in the height direction X, and when the battery cell 10 receives an external impact in the height direction X, the battery cell 10 is easily deformed; when b ₁ When the thickness of the side wall 103 is larger than 0.8mm, the structural strength and rigidity are too large, and the expansion of the electrode assembly 2 is difficult to absorb, so that the stress concentration is easy to generate in the electrode assembly 2, the phenomenon of 'lithium precipitation' occurs, and the cycle life is reduced. In the present embodiment, b is set to 0.2mm to 0.8mm so that the structural strength and rigidity of the side wall 103 are moderate, not only allowing the electrode assembly 2 to expand, but also being less likely to be deformed by external impact in the height direction X.

Referring to fig. 6 and 7, 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 disposed opposite to each other along a height direction X, the two end caps 12 respectively cover the openings on the corresponding sides, and the end caps 12 are welded or sealed with the shell 11; the side wall 103 serves as the housing 11, and the first end wall 101 and the second end wall 102 serve as the two end caps 12, respectively; the battery cell 10 further includes a positive electrode terminal 31 and a negative electrode terminal 32, the positive electrode terminal 31 is provided in the first end wall 101 in an insulating manner, the negative electrode terminal 32 is provided in the second end wall 102, the positive electrode tab 22 of the electrode assembly 2 is electrically connected to the positive electrode terminal 31, and the negative electrode tab 23 of the electrode assembly 2 is electrically connected to the negative electrode terminal 32.

In the embodiment shown in fig. 6 to 7, the battery cell further includes a first current collecting member 51 and a second current collecting member 52, the positive electrode tab 22 is electrically connected to the positive electrode terminal 31 through the first current collecting member 51, and the negative electrode tab 23 is electrically connected to the negative electrode terminal 32 through the second current collecting member 52.

In the case where the side wall 103 is used as the housing 11 and the first end wall 101 and the second end wall 102 are used as the end caps 12, respectively, the maximum thickness of the first end wall 101 is a ₁ The second end wall 102 has a maximum thickness a ₂ Satisfy a ₁ ＝a ₂ ，a ₁ ≥b。

In the present embodiment, by providing the first end wall 101 and the second end wall 102 to be equal in thickness (i.e., a ₁ ＝a ₂ ) So that the same asOne set of dies produces the two end caps 12 required for the battery cell 10, reducing the number of dies and reducing production cost.

For the battery cell 10 having the two end caps 12, in order to increase the mounting reliability of the electrode terminals, in the present embodiment, the thickness of the end caps 12 is designed to be thicker such that the thickness of the end caps 12 is greater than that of the case 11 (i.e., a ₁ ≥b，a ₂ And b), the structural strength of the end cap 12 can be improved, and the mounting reliability of the electrode terminal can be increased.

In the case where the side wall 103 serves as the housing 11 and the first end wall 101 and the second end wall 102 serve as the end caps 12, respectively, in some embodiments of the present application 1 mm. Ltoreq.a ₁ ≤2mm，0.2mm≤b≤1mm。

When a is ₁ When < 1.0mm, the thickness of the first end wall 101 and the second end wall 102 is too small, and since the thickness of the side wall 103 is smaller or equal than that of the first end wall 101, it is difficult to secure the structural strength of the case 1, and the battery cell 10 is easily deformed; when a is ₁ At > 2.0mm, the thickness of the first end wall 101 and the second end wall 102 is too large, which is disadvantageous in increasing the volumetric energy density of the battery cell 10, and is costly. In this embodiment, a will be ₁ The volume energy density of the battery cell 10 can be ensured while the structural strength of the housing 1 can be ensured by setting the size to be 1 mm-2 mm.

b may be any value between 0.2mm and 1mm, for example, 0.2mm,0.3mm,0.4mm,0.5mm,0.6mm,0.7mm,0.8mm,0.9mm,1mm, etc.

When b < 0.2mm, the thickness of the side wall 103 is too small to ensure the structural strength of the housing 1 in the height direction X, and the battery cell 10 is easily deformed; when b ₁ When the thickness of the side wall 103 is larger than 1mm, the structural strength and rigidity are also larger, the expansion of the electrode assembly 2 is difficult to absorb, the stress concentration is easy to generate in the electrode assembly 2, the phenomenon of 'lithium precipitation' is generated, and the cycle life is attenuated. In the present embodiment, b is set to 0.2mm to 1mm so that the side wall 103 The structural strength and rigidity are moderate, and the electrode assembly 2 is not only allowed to expand, but also is not easy to deform due to the external impact in the height direction X.

In some embodiments of the present application, R ₁ And H ₁ The method meets the following conditions: r is more than or equal to 0.3 ₁ /H ₁ ≤4。

When R is ₁ /H ₁ When the total rigidity of the shell 1 is smaller than 0.3, the shell is of an elongated structure, and the shell is not enough in integral rigidity and easy to deform; when R is ₁ /H ₁ When the diameter of the shell 1 is larger than the height of the shell 1, the shell 1 is of a flat structure, the overall rigidity and the structural strength of the shell are too large, expansion of the electrode assembly 2 is difficult to absorb, stress concentration is easy to occur in the electrode assembly 2, a lithium precipitation phenomenon occurs, and the cycle life is attenuated. By combining R ₁ And H ₁ The ratio of (2) is set between 0.3 and 4, so that the height and the diameter of the shell 1 are uniform, the overall rigidity and the strength of the battery cell can be ensured, and the electrode assembly 2 can be allowed to expand to a certain extent.

R ₁ /H ₁ May be any value between 0.3 and 4, for example 0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,2,3,4, etc.

In some embodiments of the present application, 100mm R ₁ ≤400mm。

When R is ₁ When less than 100mm, if the value of (R ₁ -b)/R ₁ 99% or more, the value of b needs to be set to be small. However, when the value of b is too small, the side wall 103 is easily crushed by the electrode assembly 2.

When R is ₁ When the diameter of the shell 1 is larger than 400mm, correspondingly, the diameter of the electrode assembly 2 is also larger, the number of windings of the electrode assembly 2 is more, the heat dissipation path of the inner ring pole piece of the electrode assembly 2 is too long, the heat of the inner ring pole piece cannot be timely and outwards diffused, the temperature of the inner ring pole piece is too high, and thermal runaway is easy to cause.

In the present embodiment, R is defined as ₁ The size of the inner space of the shell 1 in the radial direction of the battery cell 10 can be increased by setting the size to be between 40mm and 150mm, the volume energy density of the battery cell 10 can be increased, and the battery cell can be ensuredAnd the heat dissipation timeliness of the inner ring pole piece of the electrode assembly 2 is ensured.

In some embodiments of the present application, 100 mm.ltoreq.H ₁ ≤400mm。

When H is ₁ When less than 100mm, if it is to satisfy (H ₁ -a)/H ₁ 96% or more, the value of a needs to be set small. However, when the value of c is too small, which may result in too small structural strength of the first end wall 101 and the second end wall 102, the first end wall 101 and the second end wall 102 are difficult to resist the impact of the electrode assembly 2 when the electrode assembly 2 is shifted within the case 1.

When H is ₁ When the height of the battery cell 10 and the electrode assembly 2 is greater than 400mm, the electrode assembly 2 is too high, which may cause the electrolyte to hardly reach the top of the electrode assembly 2, the top of the electrode assembly 2 may not be sufficiently impregnated with the electrolyte, and thus the battery cell 10 may not function, resulting in a decrease in energy density of the battery cell.

In the present embodiment, by combining H ₁ The setting of 100 mm-400 mm can not only allow the size ratio of the inner space of the housing 1 in the height direction of the battery cell 10 to be increased and the volume energy density of the battery cell 10 to be increased, but also ensure that the top of the electrode assembly 2 can be fully infiltrated by the electrolyte.

In some embodiments of the present application, the battery cell 10 is a lithium ion battery, the positive active material of the battery cell 10 includes a lithium-containing phosphate, and the capacity of the battery cell 10 is C, satisfying: c is larger than or equal to 350Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]And is more than or equal to 120Ah/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, lithium nickel phosphate.

In some embodiments of the present application, the positive electrode active material of the battery cell 10 includes lithium transition metal oxide, and the capacity of the battery cell 10 is C, satisfying: c is greater than or equal to 650Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]Not less than 193Ah/L. As specific examples, the lithium transition metal oxide may include, but is not limited to, 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, lithium nickelOne or more of cobalt aluminum oxides.

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 is greater than or equal to 260Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]≥88Ah/L。

The embodiment of the application provides a battery 100, which includes a battery box 20 and the battery cell 10 provided in any one of the embodiments, where the battery cell 10 is accommodated in the battery box 20.

The embodiment of the application provides an electric device, which comprises the battery provided by any one of the embodiments.

The embodiment of the application provides an energy storage device 2000, including energy storage box 400 and the battery monomer 10 that any one of the above embodiments provided, energy storage box 400 includes battery compartment 401, and battery monomer 10 holds in battery compartment 401.

In some embodiments of the present application the sum of the volumes of the plurality of battery cells 10 is V ₁ The volume of the battery compartment 401 is V ₂ The method comprises the following steps: v is more than or equal to 0.5 ₁ /V ₂ ≤0.95。

V ₁ If the volumes of all the battery cells 10 in the battery compartment 401 are equal to the sum of the volumes of all the battery cells 10 in the battery compartment, then V ₁ Is the product of the volume of each cell 10 and the number of cells 10. V (V) ₂ The volume of the volume defined for the interior contour of the battery compartment 401. In the energy storage device 2000, V can be ₁ /V ₂ Defined as space utilization.

In the present embodiment, by defining the ratio of the sum of the volumes of the battery cells 10 to the volume of the battery compartment, i.e., V ₁ /V ₂ More than or equal to 0.5, thereby improving the space utilization of the energy storage device 2000, more battery cells 10 are arranged in the battery compartment 401 of the energy storage case 400, i.e., more energy supply structures are arranged in the unit space, thereby improving the energy density, thereby improving the capacity without expanding the occupied space.

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 401The method meets the following conditions: v (V) ₁ /V ₂ ≥0.55。

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: v (V) ₁ /V ₂ ≥0.65。

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: v (V) ₁ /V ₂ ≥0.75。

Those skilled in the art will appreciate that V is due to the fact that other components used with the battery cell 10 occupy the interior space of the battery compartment, including the liquid cooling system, control system, wiring harness, etc ₁ /V ₂ Is typically 95%, i.e. V ₁ /V ₂ ≤95％。

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other.

The above embodiments are only for illustrating the technical solution of the present application, and are not intended to limit the present application, and various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A battery cell is characterized by comprising a shell and an electrode assembly, wherein the electrode assembly is accommodated in the shell, the shell is in a cylinder shape, and the height of the shell is H ₁ The radius of the shell is R ₁ ；

The shell comprises a first end wall, a second end wall and a side wall, wherein the first end wall and the second end wall are oppositely arranged along the height direction of the shell, the side wall is connected with the first end wall and the second end wall, the sum of the thicknesses of the first end wall and the second end wall is a, the thickness of the side wall is b, and the requirements are met: (R) ₁ -b) ² *(H ₁ -a)/(R ₁ ² *H ₁ )≥96％。

2. The battery cell of claim 1, wherein (R ₁ -b)/R ₁ More than or equal to 99 percent, and R is more than or equal to 100mm ₁ ≤400mm，0.2mm≤b≤2mm。

3. The battery cell according to claim 1 or 2, wherein (H ₁ -a)/H ₁ More than or equal to 96 percent and less than or equal to 100mm of H ₁ ≤400mm，2mm≤a≤7mm。

4. The battery cell according to claim 1 or 2, wherein the housing comprises a casing and two end caps, the casing having two openings disposed opposite each other, the two end caps respectively covering the corresponding openings;

The shell is the side wall, and the two end covers are the first end wall and the second end wall respectively.

5. The battery cell of claim 4, further comprising a first insulator disposed between and abutting the first end wall and the electrode assembly and a second insulator; the second insulating piece is arranged between the second end wall and the electrode assembly and is abutted against the second end wall;

the maximum dimension of the first insulating member in the height direction is d ₁ The maximum dimension of the second insulating member in the height direction is d ₂ The method comprises the following steps: (H) ₁ -a-d ₁ -d ₂ )/H ₁ ≥90％，2mm≤d ₁ Not more than 6mm and not more than 2mm d ₂ ≤6mm。

6. The battery cell of claim 1 or 2, wherein the housing comprises a shell and an end cap, the shell having an opening, the end cap covering the opening;

the housing includes an integrally formed second end wall and side wall, and the end cap is the first end wall.

7. The battery cell of claim 6, further comprising a third insulator disposed between and in abutment with the first end wall and the electrode assembly; alternatively, the third insulator is disposed between the second end wall and the electrode assembly and abuts against the second end wall;

The maximum dimension of the third insulating member in the height direction is d ₃ The method comprises the following steps: (H) ₁ -a-d ₃ )/H ₁ More than or equal to 92 percent, and the diameter of the steel plate is more than or equal to 2mm and less than or equal to d ₃ ≤6mm。

8. The battery cell of claim 1 or 2, wherein 0.001m ³ ≤π*R ₁ ² *H ₁ ≤0.015m ³ 。

9. The battery cell as recited in claim 8, wherein the electrode assembly is a rolled configuration, the electrode assembly is a cylinder, and the height of the electrode assembly is H ₂ The radius of the electrode assembly is R ₂ The method comprises the following steps: (R) ₂ ² *H ₂ )/(R ₁ ² *H ₁ )≥85％。

10. The battery cell of claim 9, wherein R ₂ /(R ₁ -b) is not less than 97.5%, and H ₂ /(H ₁ -a)≥92.5％。

11. The battery cell of claim 9, wherein the first end wall, the second end wall, and the side wall are all aluminum alloys.

12. The battery cell of claim 9, wherein the first end wall, the second end wall, and the side wall are all of a ferrous alloy.

13. The battery cell of claim 12, wherein the housing comprises a shell and an end cap, the shell having an opening, the end cap covering the opening, the end cap being welded or crimped to the shell;

the shell comprises the second end wall and the side wall which are integrally formed, and the end cover is the first end wall;

The battery cell also comprises a positive electrode terminal, the positive electrode terminal is arranged on the second end wall in an insulating mode, the electrode assembly comprises a positive electrode lug and a negative electrode lug, the positive electrode lug is electrically connected with the positive electrode terminal, and the negative electrode lug is electrically connected with the second end wall.

14. The battery cell of claim 12, wherein the housing comprises a shell and an end cap, the shell having an opening, the end cap covering the opening, the end cap being welded or crimped to the shell;

the battery cell also comprises a positive electrode terminal, the positive electrode terminal is arranged on the first end wall in an insulating mode, the electrode assembly comprises a positive electrode lug and a negative electrode lug, the positive electrode lug is electrically connected with the positive electrode terminal, and the negative electrode lug is electrically connected with the first end wall.

15. The battery cell of claim 13, wherein the first end wall has a maximum thickness a ₁ The maximum thickness of the second end wall is a ₂ The method comprises the following steps: a, a ₁ ≥a ₂ ，a ₁ ≥b。

16. The battery cell of claim 15, wherein 1mm +.a ₁ ≤2mm，0.5mm≤a ₂ ≤1.5mm，0.2mm≤b≤0.8mm。

17. The battery cell of claim 11, wherein the housing comprises a shell and two end caps, the shell having two openings disposed opposite each other, the two end caps respectively covering the openings;

the shell is the side wall, the two end covers are the first end wall and the second end wall respectively, and the end covers are welded or sealed with the shell;

the battery cell also comprises a positive electrode terminal and a negative electrode terminal, wherein the positive electrode terminal is arranged on the first end wall, the negative electrode terminal is arranged on the second end wall, the electrode assembly comprises a positive electrode lug and a negative electrode lug, the positive electrode lug is electrically connected with the positive electrode terminal, and the negative electrode lug is electrically connected with the negative electrode terminal.

18. The battery cell of claim 17, wherein the first end wall has a maximum thickness a ₁ The maximum thickness of the second end wall is a ₂ The method comprises the following steps: a, a ₁ ＝a ₂ ，a ₁ ≥b。

19. The battery cell of claim 18, wherein 1mm +.a ₁ ≤2mm，0.2mm≤b≤1mm。

20. The battery cell of claim 8, wherein 0.3R +. ₁ /H ₁ ≤4，100mm≤R ₁ ≤400mm，100mm≤H ₁ ≤400mm。

21. The battery cell of claim 1 or 2, wherein the positive electrode material of the battery cell comprises a lithium-containing phosphate, the battery cell having a capacity C that satisfies: c is larger than or equal to 350Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]≥120Ah/L。

22. The battery cell of claim 1 or 2, wherein the positive electrode material of the battery cell comprises a lithium transition metal oxide, the battery cell having a capacity C that satisfies:C≥650Ah，C/[π*(R ₁ -b) ² *(H ₁ -a)]≥193Ah/L。

23. the battery cell of claim 1 or 2, wherein the battery cell is a sodium ion battery, and the capacity of the battery cell is C, satisfying: c is greater than or equal to 260Ah, C/[ pi ] (R ₁ -b) ² *(H ₁ -a)]≥88Ah/L。

24. A battery comprising a cell according to any one of claims 1-23.

25. An electrical device comprising the battery of claim 24, the battery being configured to provide electrical energy to the electrical device.

26. An energy storage device, comprising:

the energy storage box body is provided with a battery compartment;

a plurality of the battery cells of any one of claims 1-23, a plurality of the battery cells disposed within the battery compartment.

27. The energy storage device of claim 26, wherein the sum of the volumes of said housings of a plurality of said cells is V ₁ The volume of the battery compartment is V ₂ The method comprises the following steps: v is more than or equal to 0.5 ₁ /V ₂ ≤0.95。