ELECTRODE ASSEMBLY, MANUFACTURING METHOD AND APPARATUS THEREFOR, BATTERY, AND POWER CONSUMING DEVICE

Provided is an electrode assembly and a manufacturing method and apparatus therefor, a battery, and a power consuming device, the electrode assembly being used for a battery cell and the electrode assembly including: a first electrode plate and a second electrode plate that have opposite polarities, where the first electrode plate and the second electrode plate each include a main body portion and a tab projecting from the main body portion, and the first electrode plate and the second electrode plate are wound about a winding axis; and an end portion of the wound main body includes at least one conductive region and at least one liquid guiding region, where the tab is led out of the conductive region, is wound by at least one turn, and is used for electrical connection to a terminal of the battery cell.

TECHNICAL FIELD

The present application relates to the technical field of batteries, and in particular, to an electrode assembly and a manufacturing method and apparatus therefor, a battery, and a power consuming device.

BACKGROUND ART

With the advantages such as high energy density, high power density, many times of cyclic use, and long storage time, batteries such as lithium-ion batteries have been widely applied in electric vehicles.

However, how to enhance the working performance of batteries of the electric vehicles has been always a problem in this industry.

SUMMARY OF THE INVENTION

The present application aims to enhance the performance of batteries.

According to a first aspect of the present application, an electrode assembly for a battery cell is provided. The electrode assembly comprises: a first electrode plate and a second electrode plate that have opposite polarities, the first electrode plate and the second electrode plate each comprising a main body portion and a tab projecting from the main body portion, and the first electrode plate and the second electrode plate being wound about a winding axis such that the respective main body portions form a wound main body.

An end portion of the wound main body comprises at least one conductive region and at least one liquid guiding region, wherein the tab is led out of the conductive region, is wound by at least one turn, and is used for electrical connection to a terminal of the battery cell; and the liquid guiding region is arranged adjacent to the conductive region in a radial direction of the wound main body and is used for guiding an electrolyte to flow into an interior of the wound main body.

In the embodiment of the present application, the end portion of the wound main body simultaneously has the conductive region and the liquid guiding region. Since no tab is provided in the liquid guiding region, after the tab of the conductive region is flattened, the electrolyte in the battery cell also easily flows into the interior of the wound main body through a gap between the first electrode plate and the second electrode plate in the liquid guiding region, ensuring the infiltration performance of the electrode assembly, so that the electrolyte can sufficiently react with active materials on the first electrode plate and the second electrode plate during charging and discharging of the battery, and the performance of the battery cell is thus optimized.

Furthermore, since the tab extends continuously and is wound by at least one turn in the conductive region, the tab has better connection strength with the main body portion in a circumferential direction, such that a root portion of the tab has a better self-supporting effect, a crumpling phenomenon of the tab is prevented in the process of flattening the tab by applying a circumferential acting force, the shape of a flattened region is stabilized, the effect of welding the tab and the terminal is optimized, it is ensured that the electrode assembly reliably transmits electric energy outwards, and the overcurrent capacity is improved. In addition, particles generated during welding of the tab are less prone to dropping between the first electrode plate and the second electrode plate of the liquid guiding region in the circumferential direction, so that the working reliability of the electrode assembly can be improved, and the problem of short circuit or scratch of the electrode plate can be solved.

Moreover, by providing the continuous tab on part of the winding length of the main body portion, the overcurrent capacity of the tab can be satisfied without providing discrete tabs on the entire winding length of the main body portion, so that a process of die-cutting an electrode plate can be simplified, and meanwhile, when the first electrode plate and the second electrode plate are wound to form the wound main body, there is also no need to perform alignment of the tabs, thus the process can be simplified, and the production efficiency of the electrode assembly can be increased.

In some embodiments, the tab is wound by a plurality of turns in the conductive region.

In the embodiment of the present application, the supporting effect on the tab is further strengthened by winding the tab by a plurality of turns in the conductive region and making bent portions of adjacent tabs overlapped with each other after flattening, so that the tab can be prevented from being crumpled during flattening, the shapes of the bent portions can be stable, and the effect of welding the tab and the terminal can be optimized; in addition, the welding area of the tab and the terminal after flattening can also be increased, so that the tab and the terminal can be welded more firmly, it is ensured that the electrode assembly reliably transmits electric energy outwards, and the overcuffent capacity is improved.

In some embodiments, the stun of the number of the conductive regions and the number of the liquid guiding regions is greater than or equal to three, and the regions are alternately provided in the radial direction of the wound main body.

In this embodiment of the present application, by alternately providing at least three conductive regions and at least three liquid guiding regions in the radial direction of the wound main body, the electrolyte entering the interior of the wound main body from the liquid guiding regions can more easily reach the conductive regions, which facilitates rapid infiltration of the electrolyte; also, this structure can shorten a transmission distance of electrons from the liquid guiding region to the conductive region, ensure the timely and effective transmission of electrons, improve the uniformity of current distribution, and solve the polarization problem of the electrode assembly.

In some embodiments, the conductive region is located in a middle region of the end portion of the wound main body in the radial direction, and a liquid guiding region is provided on either side of the conductive region in the radial direction.

In this embodiment of the present application, a liquid guiding region is provided on either side of the conductive region in the radial direction, and the electrolyte can simultaneously enter the interior of the wound main body via the two liquid guiding regions and permeates into the portions of the first electrode plate and the second electrode plate located in the conductive region, so that the infiltration performance of the electrolyte of the electrode assembly can be further enhanced. Furthermore, the transmission distance of the electrons from an inner-layer liquid guiding region and an outer-layer liquid guiding region to the conductive region is shortened, so that the uniformity of current distribution can be improved, and the polarization problem can be solved. Moreover, one conductive region is provided to facilitate electrical connection of the tab and the terminal. All of the above advantages can enhance the performance of the battery.

In some embodiments, at least one of the first electrode plate and the second electrode plate is provided with a plurality of tabs at intervals in a winding direction, so as to form a plurality of radially spaced conductive regions at the end portion of the wound main body.

In this embodiment of the present application, the electrolyte entering the interior of the wound main body via the liquid guiding region is allowed to simultaneously permeate into the conductive regions on two sides, so that the electrolyte smoothly reaches the portions of the first electrode plate and the second electrode plate located in the conductive region, and the infiltration performance of the electrolyte of the electrode assembly is enhanced. Moreover, the electrons can simultaneously reach the conductive region from an inner side and an outer side of the liquid guiding region in the radial direction, so that the transmission distance of the electrons can be greatly shortened, the uniformity of current distribution can be improved, and the polarization problem can be solved; when the first electrode plate and the second electrode plate are longer after being unwound, the polarization problem caused by the long local transmission distance of the electrons can be better solved by designing segmented tabs. Furthermore, by providing the plurality of conductive regions, the overall length of the tab disposed in the radial direction can be increased to facilitate welding of the tab and an adapter, and the tab is electrically connected to the terminal by means of the adapter. All of the above advantages can enhance the performance of the battery.

In some embodiments, two conductive regions are provided and are respectively located on an inner side and an outer side of the end portion of the wound main body in the radial direction, and the liquid guiding region is located between the two conductive regions.

In this embodiment of the present application, the two conductive regions are provided in a non-infiltration bottleneck region, for example, an inner ring and an outer ring of the electrode assembly, so that an infiltration effect can be optimized, and the polarization problem can also be solved.

In some embodiments, one conductive region and one liquid guiding region are respectively provided, and the conductive region is located on an inner side of the conductive region in the radial direction.

In this embodiment of the present application, the conductive region is provided on the inner side of the liquid guiding region, and ou the basis of ensuring an infiltration characteristic of the electrode assembly by means of the liquid guiding region, the tab can also be prevented from being in contact with an inner wall of a shell after the tab is flattened to form the bent portion, or the particles can be prevented from falling onto the inner side wall of the shell when the tab and the terminal are welded, so as to avoid short circuit and improve the working safety of the battery cell.

In some embodiments, the liquid guiding regions at two ends of the wound main body have the same radial dimension, and the conductive regions at the two ends of the wound main body have the same radial dimension.

In this embodiment of the present application, the two ends of the wound main body are structurally symmetrical, so that the first electrode plate and the second electrode plate can be processed to have the same structure, the processing difficulty of the electrode assembly can be reduced, and the production efficiency of the electrode assembly can be increased.

In some embodiments, the liquid guiding region at one end of the wound main body has the same radial dimension as the conductive region at the other end.

In this embodiment of the present application, the conductive regions and the liquid guiding regions at the two ends of the wound main body are provided in a staggered manner in the radial direction, namely, the conductive region at one end of the wound main body corresponds to the liquid guiding region at the other end, such that the wound main body has the liquid guiding region at any position in the radial direction, the electrolyte is allowed to enter the interior of the wound main body more quickly and sufficiently, the distribution of the electrolyte in the interior of the electrode assembly is more uniform, which makes the electrolyte uniformly react with the active materials on the first electrode plate and the second electrode plate dining the charging and discharging of the battery, and the performance of the battery cell is thus optimized.

In some embodiments, the electrode assembly further comprises a separator for separating the first electrode plate from the second electrode plate; and the separator, the main body portion of the first electrode plate and the main body portion of the second electrode plate are wound to form a wound main body.

In an extending direction of the winding axis, the portion of the separator located in the liquid guiding region extends beyond a side edge of the main body portion of the first electrode plate and beyond a side edge of the main body portion of the second electrode plate.

In this embodiment of the present application, the separator is designed to be in a stepped shape and is widened in the liquid guiding region, so that a side edge of the separator extends outwards between the first electrode plate and the second electrode plate in the liquid guiding region and is soaked in the electrolyte to allow the separator to more easily absorb the electrolyte wider a capillary action, the infiltration performance of the electrode assembly is enhanced, and the performance of the battery cell is thus enhanced.

In some embodiments, the electrode assembly further comprises a separator for separating the first electrode plate from the second electrode plate. The main body portion of at least one of the first electrode plate and the second electrode plate comprises an active material region and a flow guiding region provided side by side in the extending direction of the winding axis, wherein the flow guiding region is located on an outer side of the active material region, and a gap between the surface of the main body portion located in the flow guiding region and the separator is greater than a gap between the surface of the main body portion located in the active material region and the separator.

In this embodiment of the present application, the gap between the surface of the main body portion located in the flow guiding region and the separator is set to be greater than the gap between the surface of the main body portion located in the active material region and the separator, so that a larger capillary gap can be formed between the flow guiding region and the separator, and after the electrolyte is absorbed into an end portion of the separator, the electrolyte can rapidly enter the end portion of the wound main body and then further enter the active material region to react with an active material. This structure allows the gap between the main body portion and the separator to be gradually decreased from outside to inside, facilitating rapid entry of the electrolyte.

In some embodiments, the flow guiding region of at least one of the first electrode plate and the second electrode plate comprises an infiltration region adjacent to the active material region, with the gap between the surface of the main body portion located in the infiltration region and the separator being gradually increased from inside to outside in the extending direction of the winding axis.

In this embodiment of the present application, it is possible to introduce the electrolyte into the active material region via the infiltration region after the electrolyte is absorbed at the end portion of the separator, facilitating rapid entry of the electrolyte into the interior of the wound main body for reaction.

In some embodiments, the flow guiding region of at least one of the first electrode plate and the second electrode plate comprises an infiltration region adjacent to the active material region. The main body portion of at least one of the first electrode plate and the second electrode plate comprises a current collector, an active material layer and an infiltration layer, wherein the active material layer is provided on a surface of the current collector and located in the active material region, the infiltration layer is provided on the surface of the current collector and located in the infiltration region, and the infiltration layer has a higher liquid absorption capacity than the active material layer.

In this embodiment of the present application, by coating the region of the main body portion close to the outer side with an infiltration layer having a higher liquid absorption capacity than the active material layer, the capability of absorbing the electrolyte by the end portion of the wound main body can be improved by using the material characteristic of the infiltration layer so as to facilitate rapid absorption of the electrolyte into the interior of the wound main body.

In some embodiments, the infiltration layer comprises an inorganic ceramic coating, a high molecular polymer, and a binder.

In some embodiments, the flow guiding region of at least one of the first electrode plate and the second electrode plate further comprises a guide region, wherein the region of the current collector beyond the infiltration layer in the extending direction of the winding axis forms the guide region.

In this embodiment of the present application, the coating layer is not provided in the guide region, so that the gap between the current collector and the separator in the guide region is greater than the gap between the surface of the infiltration layer and the separator, and a multi-stage electrolyte absorption channel can be formed at the end portion of the wound main body located in the liquid guiding region. Also, the distance between the first electrode plate or the second electrode plate and the separator is gradually decreased from the guide region, the infiltration region to the active material region, so that the liquid absorption efficiency can be significantly increased, and the infiltration characteristic of the electrode assembly can be improved, and thus the performance of the battery cell can be enhanced.

In some embodiments, the first electrode plate is a positive electrode plate and is sequentially provided with an active material region, an infiltration region, and a guide region from inside to outside in the extending direction of the winding axis, and the second electrode plate is a negative electrode plate and is sequentially provided with an active material region and a guide region from inside to outside along the winding axis.

In this embodiment of the present application, considering that the compaction density of the positive electrode plate is relatively high and the speed of the electrolyte entering the positive electrode plate is relatively low, the speed of the electrolyte permeating into a positive electrode active material can be increased by adding an infiltration region to the positive electrode plate; and the speed of the electrolyte entering the negative electrode plate is higher than that of the electrolyte entering the positive electrode plate, and by introducing the electrolyte only via the guide region, a manufacturing process of the negative electrode plate can be simplified. In this embodiment, the speeds of the electrolyte entering the positive electrode plate and the negative electrode plate can be similar, and the production difficulty of the electrode assembly can also be reduced.

In some embodiments, the side edge of the separator located in the liquid guiding region of at least one of the first electrode plate and the second electrode plate is located between an outer side edge of the flow guiding region and an outer side edge of the tab.

In this embodiment of the present application, the side edge of the separator is provided beyond the outer side edge of the flow guiding region, so that the extending portion of the separator can be soaked in the electrolyte so as to absorb the electrolyte under the capillary action; also, the side edge of the separator is not beyond the outer side edge of the tab, so that excessive extension of the separator in the conductive region can be prevented from affecting the flattening of the tab, and the conductive effect of the tab can be ensured.

In some embodiments, the flow guiding region is consistent with the active material region in extension length in a circumferential direction of the wound main body.

In this embodiment of the present application, the manufacturing difficulty of the electrode plate provided with the flow guiding region can be reduced, and the flow guiding region is consistent with the active material region in extension length, so that the electrolyte can be better guided to reach the active material region over the whole coating length of the active material region, the electrolyte can be uniformly distributed over the whole winding length of the electrode plate, and the performance of the battery cell can be thus enhanced.

According to a second aspect of the present application, a battery cell is provided, comprising: a shell provided with an opening; an end cap assembly for closing the opening, the end cap assembly comprising an end cap body and a terminal provided on the end cap body; and the electrode assembly of the above-mentioned embodiment, provided in the shell, with a tab of a first electrode plate or a tab of a second electrode plate being electrically comiected to a terminal.

In the battery cell of this embodiment of the present application, since the electrode assembly has a superior infiltration characteristic, the tab and the terminal have higher electrical connection reliability, and the performance of the battery cell can be enhanced.

According to a third aspect of the present application, a battery is provided, comprising: the battery cell of the above-mentioned embodiment; and a case for receiving the battery cell.

According to a fourth aspect of the present application, a power consuming device is provided, comprising the battery of the above-mentioned embodiment. The battery is used for supplying electric energy to the power consuming device.

According to a fifth aspect of the present application, a manufacturing method for a battery assembly is provided, comprising:

providing a first electrode plate and a second electrode plate that have opposite polarities, the first electrode plate and the second electrode plate each comprising a main body portion and a tab projecting from the main body portion; and

winding the first electrode plate and the second electrode plate about a winding axis such that the respective main body portions form a wound main body, an end portion of the wound main body comprising at least one conductive region and at least one liquid guiding region.

The tab is led out of the conductive region, is wound by at least one turn, and is used for electrical connection to a terminal of the battery cell, and the liquid guiding region is arranged adjacent to the conductive region in a radial direction of the wound main body and is used for guiding an electrolyte to flow into the interior of the wound main body.

According to a sixth aspect of the present application, a manufacturing apparatus for an electrode assembly is provided, comprising:

an electrode plate providing device configured to provide a first electrode plate and a second electrode plate that have opposite polarities, the first electrode plate and the second electrode plate each comprising a main body portion and a tab projecting from the main body portion; and

an electrode plate winding device configured to wind the first electrode plate and the second electrode plate about a winding axis such that the respective main body portions form a wound main body, an end portion of the wound main body comprising at least one conductive region and at least one liquid guiding region.

The tab is led out of the conductive region, is wound by at least one turn, and is used for electrical connection to a terminal of the battery cell, and the liquid guiding region is arranged adjacent to the conductive region in a radial direction of the wound main body and is used for guiding an electrolyte to flow into the interior of the wound main body.

In the accompanying drawings, the figures are not drawn to actual scale.

LIST OF REFERENCE NUMERALS

DETAILED DESCRIPTION OF EMBODIMENTS

The following further describes in detail implementations of the present application with reference to the accompanying drawings and embodiments. The detailed description of the following embodiments and the drawings are used to illustrate the principle of the present application by way of example, but shall not be used to limit the scope of the present application. In other words, the present application is not limited to the described embodiments.

In the description of the present application, it should be noted that, unless otherwise specified, “a plurality of” means at least two. An orientation or a positional relationship indicated by the terms “upper”, “lower”, “left”, “right”, “inner”, “outer”, etc. is merely for convenient and brief description of the present application, rather than indicating or implying that an indicated apparatus or element needs to have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the present application.

In addition, the terms “first”, “second”, “third”, etc. are merely for the purpose of description, and shall not be construed as indicating or implying relative importance. “Perpendicular” is not necessarily perpendicular in the strict sense, and a range of errors is allowed. “Parallel” is not necessarily parallel in the strict sense, and a range of errors is allowed. The orientation terms in the following description all indicate directions shown in the drawings, and do not impose a limitation on a specific structure in the present application.

In the description of the present application, it should further be noted that, the terms “mount”, “engage”, and “connect” should be interpreted in the broad sense unless explicitly defined and limited otherwise, which, for example, may mean a fixed connection, a detachable connection or an integral connection; or may mean a direct connection, or an indirect connection by means of an intermediary. For those of ordinary skill in the art, specific meanings of the foregoing terms in the present application may be understood in specific circumstances.

The phrase “embodiment” mentioned herein means that the specific features, structures and characteristics described in conjunction with the embodiment may be included in at least some embodiments of the present application. The phrase at various locations in the specification does not necessarily refer to the same embodiment, or an independent or alternative embodiment exclusive of another embodiment. Those skilled in the art understand explicitly or implicitly that an embodiment described herein may be combined with another embodiment.

In the description of the embodiments of the present application, the term “a plurality of” means two or more (including two), similarly the term “a plurality of groups” means two or more groups (including two groups), and the term “a plurality of pieces” means two or more pieces (including two pieces).

The present application uses the description of the orientations or positional relationships indicated by the terms “upper”, “lower”, “top”, “bottom”, “front”, “rear”, “inner”, “outer”, etc., which are merely for convenient description of the present application, rather than indicating or implying that a device referred to needs to have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the scope of protection of the present application.

A 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 or a magnesium-ion battery, etc., which is not limited by the embodiments of the present application. The battery cell may be in a cylindrical shape, a flat shape, a cuboid shape or in another shape, which is not limited by the embodiments of the present application. The battery cells are generally classified into three types depending on the way of packaging: cylindrical battery cells, prismatic battery cells and pouch battery cells, which are also not limited in the embodiments of the present application.

An existing battery cell generally includes a shell and an electrode assembly received in the shell, and the interior of the shell is filled with an electrolyte. The electrode assembly is mainly formed by stacking or winding a first electrode plate and a second electrode plate that have opposite polarities, and a separator is generally provided between the first electrode plate and the second electrode plate. The portions of the first electrode plate and the second electrode plate that are coated with an active material form a main body portion of the electrode assembly, and the portions of the first electrode plate and the second electrode plate that are not coated with the active material respectively form a first tab and a second tab. In a lithitun-ion battery, the first electrode plate may be a positive electrode plate, which includes a positive electrode current collector and positive electrode active material layers provided on two sides of the positive electrode current collector, wherein the material of the positive electrode current collector may be, for example, aluminun, and a positive electrode active material may be, for example, lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc.; and the second electrode plate may be a negative electrode plate, which includes a negative current collector and negative electrode active material layers provided on two sides of the negative current collector, wherein the material of the negative current collector may be, for example, copper, and a negative electrode active material may be, for example, graphite or silicon, etc. The first tab and the second tab may jointly be located at one end of the main body portion or respectively at two ends of the main body portion. During the charging and discharging of the battery cell, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs are connected to a terminal to form a current loop.

In processing and assembly procedures of the electrode assembly, if the electrode plates are welded after being wound, a gap between adjacent tabs is large, causing the whole to be relatively loosely arranged, and a spurious joint and a burst point phenomenon will occur during laser welding, so it is often necessary to flatten the tabs such that the tabs are bent and deformed and the adjacent tabs are more compact, facilitating connection of the tabs to the terminal and assembly of the battery cell. In order to facilitate the application of an external force to the tabs in a circumferential direction of the electrode assembly for flattening, the tab is generally designed to continuously extend along the entire winding length of the tab.

The inventor of the present application has found in practice that the flattening treatment of the tabs causes end portions of two adjacent tab layers in a laminated structure to abut together and to form a closed structure, and such a closed structure impedes, to some extent, a passage of the electrolyte from a space outside the tabs to the main body portion, thereby adversely affecting an infiltration effect of the electrolyte in the electrode assembly on the active material, resulting in the phenomenon that the positive or negative electrode active material cannot sufficiently participate in reaction, possibly affecting the efficiency of the electrode assembly, and thus affecting the battery performance.

Therefore, the infiltration effect of the electrolyte in the electrode assembly on the active material is an important factor for ensuring the high performance of a battery. The inventor intends to improve the infiltration effect by changing a material of the separator or a hierarchical structure of the separator, but this change leads to an increase in the cost of the electrode assembly and a more complicated manufacturing process.

Another idea is that a continuous tab is die-cut to form a plurality of discrete tabs, and a stack of tabs are formed after winding, wherein the tab has a tab region and a non-tab region in the circumferential direction of the electrode assembly after the tab is flattened, the non-tab region facilitates infiltration of the electrolyte, and the tab region is used for connection to a terminal. However, there is a crumpling phenomenon after the tab is die-cut and then flattened, and due to the soft material of the tab, a self-supporting effect cannot be formed at a root portion of the tab when a circumferential acting force is applied for flattening the tab, making a flattened region not flat enough and affecting a subsequent welding effect; moreover, particles generated during tab welding are liable to fall between the electrode plates in the non-tab region.

On the basis of the findings of the above-mentioned problem, the inventor of the present application has improved the structural design of the electrode assembly, so as to increase the infiltration effect of the electrolyte in the electrode assembly on the active material and to enhance the performance of the battery. Various embodiments of the present application will be further described below with reference to the accompanying drawings.

A power consuming device includes a battery for supplying electric energy to a device, and may be a mobile phone, a portable apparatus, a laptop, an electric motorcycle, an electric vehicle, a ship, a spacecraft, an electric toy, or an electric tool, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle, or a spaceship. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy, and an electric airplane toy. The electric tool includes an electric tool for metal cutting, an electric tool for grinding, an electric tool for assembling and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an electric impact drill, a concrete vibrator, and an electric planer.

As shown inFIG.1, a power consuming device may be a vehicle300, for example, a new energy vehicle. The new energy vehicle may be a battery electric vehicle, a hybrid electric vehicle, an extended-range electric vehicle, or the like; alternatively, the power consuming device may also be an unmanned aerial vehicle, a ship, or the like. Specifically, the vehicle300may include an axle301, wheels302connected to the axle301, a motor303, a controller304and a battery200, wherein the motor303is used for driving the axle301to rotate, the controller304is used for controlling operation of the motor303, and the battery200may be provided at the bottom, head, or tail of the vehicle300, and used for providing electric energy for operation of the motor303and other components in the vehicle.

As shown inFIG.2, the battery200includes a case201and a battery cell100. In the battery200, one or more battery cells100may be provided. If a plurality of battery cells100are provided, the plurality of battery cells100may be in series connection, in parallel connection or in series-parallel connection, and the series-parallel connection refers to that the plurality of battery cells100are in series and parallel connection. It is possible that the plurality of battery cells100are firstly connected in series or in parallel or in series and parallel to form a battery module, and then a plurality of battery modules are connected in series or in parallel or in series and parallel to form a whole body and are received in the case201. It is also possible that all the battery cells100are directly connected in series or in parallel or in series and parallel, and then the whole body composed of all the battery cells100is received in the case201.

The case201is hollow inside and used for receiving one or more battery cells100, and the case201may also be sized in different shapes according to the shape, number, combination manner and other requirements of the received battery cells100. For example, the case201may include: a receiving portion201A, a first cover body201B and a second cover body201C, wherein two opposite ends of the receiving portion201A both have openings, and the first cover body201B and the second cover body201C are respectively used for closing the openings at two ends of the receiving portion201A. InFIG.2, the receiving portion201A is of a rectangular cylindrical structure according to the arrangement manner of the plurality of battery cells100.

As shown inFIG.3, the battery cell100includes a shell101, an end cap assembly102, and an electrode assembly10. The battery cell100may include, for example, a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium/lithium ion battery, or a magnesium-ion battery, etc.

The shell101has a hollow structure for receiving the electrode assembly10, and the shell101has an opening1011; and the end cap assembly102is used for closing the opening1011, the end cap assembly102includes an end cap body1021and a terminal1022provided on the end cap body1021, and the end cap body1021is further provided with a pressure relief component1023for pressure relief when an internal pressure of the battery cell100exceeds a preset pressure.

FIG.3illustrates an embodiment in which only one electrode assembly10is provided, and those skilled in the art will appreciate that in other embodiments, the battery cell100may also include a plurality of electrode assemblies10, and the terminals1022may also be designed according to the number and arrangement manner of the electrode assemblies10. Furthermore, depending on the shape and placement manner of the electrode assemblies10, as well as the combination manner of the plurality of electrode assemblies10, the shell101may be in a cylindrical shape, a flat shape, a cuboid shape, or in another shape.

As shown inFIG.4, the electrode assembly10is provided in the shell101, a first electrode plate and a second electrode plate that have opposite polarities each have a tab12, and the tab12of the first electrode plate or the tab12of the second electrode plate is electrically connected to the terminal1022. The end cap assembly102may further include an adapter1025, wherein the adapter1025is provided between the end cap body1021and the electrode assembly10and used for achieving electrical connection between the tab12and the terminal1022. As shown inFIG.5, in order to achieve insulation between the end cap body1021and the adapter1025, the end cap assembly102may further include an insulator1024provided between the end cap body1021and the adapter1025.

In the embodiments shown inFIGS.4and5, the shell101of the battery cell100is in the shape of a hollow cylinder with two ends both having openings1011, and the two openings1011are both closed by the end cap assemblies102. The electrode assembly10can be put into the shell101from the opening1011, the first electrode plate and the second electrode plate are wound to form a cylindrical electrode assembly10, and the respective tabs12of the first electrode plate and the second electrode plate are respectively led out of two ends of the electrode assembly10in an axial direction, and are both electrically connected to the terminals1022at the corresponding ends via the adapters1025.

In other optional embodiments, the shell101of the battery cell100is in the shape of a hollow cylinder with one end being closed and with the other end having the opening1011and being closed by the end cap assembly102, the first electrode plate and the second electrode plate are wound to form a cylindrical electrode assembly10, the respective tabs12of the first electrode plate and the second electrode plate are respectively led out of the two ends of the electrode assembly10in an axial direction, the tab12of the first electrode plate, for example, a negative electrode plate, is electrically connected to the terminal1022via the adapter1025, and the tab12of the second electrode plate, for example, a positive electrode plate, is directly electrically connected to an end wall of the shell101.

The structure of the electrode assembly10will be described in detail below.

In some embodiments, as shown inFIGS.6to11, the electrode assembly10is used for the battery cell100. The electrode assembly10includes: a first electrode plate1and a second electrode plate2that have opposite polarities, wherein the first electrode plate1and the second electrode plate2each include a main body portion11and a tab12projecting from the main body portion11, and the first electrode plate1and the second electrode plate2are wound about a winding axis K such that the respective main body portions11form a wound main body S.

An end portion of the wound main body S includes at least one conductive region121and at least one liquid guiding region111, wherein the tab12is led out of the conductive region121, is wound by at least one turn, and is used for electrical connection to the terminal1022of the battery cell100; and the liquid guiding region111is arranged adjacent to the conductive region121in a radial direction of the wound main body S and is used for guiding an electrolyte to flow into the interior of the wound main body S.

The first electrode plate1and the second electrode plate2are substantially the same in shape, and can have elongated strip-like structures; the first electrode plate1and the second electrode plate2are superposed in a direction perpendicular to the winding axis K; and the formed wound main body S may be in a cylindrical shape, a flat shape, a cuboid shape, or in another shape. For example, the first electrode plate1is a positive electrode plate, and the second electrode plate2is a negative electrode plate; alternatively, the first electrode plate1is a negative electrode plate, and the second electrode plate2is a positive electrode plate. The electrode assembly10further includes a separator3, wherein the separator3is used for separating the first electrode plate1from the second electrode plate2; and the separator3, the main body portion11of the first electrode plate1and the main body portion of the second electrode plate2are wound to form a wound main body S.

Optionally, one end portion of the wound main body S includes at least one conductive region121and at least one liquid guiding region111, and the tab12is led out of the conductive region121and is wound by at least one turn, such that both the conductive region121and the liquid guiding region111fonn an annular structure; and the tab12is flattened to form a bent portion, and is electrically connected to the terminal1022of the battery cell100via the bent portion, for example, in a welding manner. In an unwound state of the first electrode plate1or the second electrode plate2, the tab12may be provided in a middle region, an end region or another region of the electrode plate.

The liquid guiding region111is not provided with the tab12, and a gap between the first electrode plate1or the second electrode plate2and the separator3is in communication with the outside of the electrode assembly10, so that it is easier for the electrolyte to enter the gap between the first electrode plate1or the second electrode plate2and the separator3and to flow into the interior of the wound main body S; and the separator3can also fully play a liquid absorption effect to make the electrolyte sufficiently react with active materials on the first electrode plate1and the second electrode plate2during charging and discharging of the battery.

Optionally, two end portions of the wound main body S each include at least one conductive region121and at least one liquid guiding region111, and the electrolyte can infiltrate from the liquid guiding regions111at the two ends of the wound main body S to the interior, so that an infiltration path of the electrolyte can be shortened, and the liquid absorption effect can be improved.

In the embodiment of the present application, the end portion of the wound main body S simultaneously has the conductive region121and the liquid guiding region111. Since no tab12is provided in the liquid guiding region111, after the tab12of the conductive region121is flattened, the electrolyte in the battery cell100also easily flows into the interior of the wound main body S through the gap between the first electrode plate1and the second electrode plate2in the liquid guiding region111, ensuring the infiltration performance of the electrode assembly10, so that the electrolyte can sufficiently react with the active materials on the first electrode plate1and the second electrode plate2during charging and discharging of the battery, and the performance of the battery cell100is thus optimized.

Furthermore, since the tab12extends continuously and is wound by at least one turn in the conductive region121, the tab has better connection strength with the main body portion11in a circumferential direction, such that a root portion of the tab12has a better self-supporting effect, a crumpling phenomenon of the tab12is prevented in the process of flattening the tab12by applying a circumferential acting force, the shape of a flattened region is stabilized, the effect of welding the tab12and the terminal1022is optimized, it is ensured that the electrode assembly10reliably transmits electric energy outwards, and the overcurrent capacity is improved. In addition, particles generated during welding of the tab12are less prone to dropping between the first electrode plate1and the second electrode plate2of the liquid guiding region111in the circumferential direction, so that the working reliability of the electrode assembly10can be improved, and the problem of short circuit or scratch of the electrode plate can be solved.

Moreover, by providing the continuous tab12on part of a winding length of the main body portion11, the overcunent capacity of the tab12can be satisfied without providing discrete tabs12on the entire winding length of the main body portion11, so that a process of die-cutting an electrode plate can be simplified, and meanwhile, when the first electrode plate1and the second electrode plate are wound to form the wound main body S, there is also no need to perform alignment of the tabs12, thus the process can be simplified, and the production efficiency of the electrode assembly10can be increased.

In some embodiments, as shown inFIGS.6to11, the tab12is wound by a plurality of turns in the conductive region121. The tab12may be wound by at least two turns, for example, at least five turns in order to achieve a preferred self-supporting effect of the tab12. The number of the winding turns may be designed on the basis of the overcunent capacity and polarization of the electrode assembly10.

In the embodiment of the present application the supporting effect on the tab12is further strengthened by winding the tab12by a plurality of turns in the conductive region121and making the bent portions of adjacent tabs12overlapped with each other after flattening, so that the tab12can be prevented from being crumpled during flattening, the shapes of the bent portions can be stable, and the effect of welding the tab12and the terminal1022can be optimized; in addition, the welding area of the tab12and the terminal1022after flattening can also be increased, so that the tab12and the terminal1022can be welded more firmly, it is ensured that the electrode assembly10reliably transmits electric energy outwards, and the overcurrent capacity is improved.

In some embodiments, the stun of the number of the conductive regions121and the number of the liquid guiding regions111is greater than or equal to three, and the regions are alternately provided in the radial direction of the wound main body S. As shown inFIGS.6and7, one conductive region121is provided, and two liquid guiding regions111are provided. As shown inFIGS.8and9, two conductive regions121are provided, and one liquid guiding region111is provided.

In this embodiment of the present application, by alternately providing at least three conductive regions121and at least three liquid guiding regions111in the radial direction of the wound main body S, the electrolyte entering the interior of the wound main body S from the liquid guiding regions111can more easily reach the conductive regions121, which facilitates rapid infiltration of the electrolyte; also, this structure can shorten a transmission distance of electrons from the liquid guiding region111to the conductive region121, ensure the timely and effective transmission of electrons, improve the uniformity of current distribution, and solve the polarization problem of the electrode assembly10.

In some embodiments, as shown inFIG.6andFIG.7, the conductive region121is located in the middle region of the end portion of the wound main body S in the radial direction, and a liquid guiding region111is provided on either side of the conductive region121in the radial direction.

The term “middle region” mentioned herein is not intended to exactly indicate that the conductive region is directly located at a middle position in the radial direction, and it falls within the scope of protection of the present application that the conductive region121is located relatively inwards or outwards in the radial direction.

In this embodiment of the present application, a liquid guiding region111is provided on either side of the conductive region121in the radial direction, and the electrolyte can simultaneously enter the interior of the wound main body S via the two liquid guiding regions111and permeates into the portions of the first electrode plate1and the second electrode plate2located in the conductive region121, so that the infiltration performance of the electrolyte of the electrode assembly10can be further enhanced. Futhermore, the transmission distance of the electrons from an inner-layer liquid guiding region111and an outer-layer liquid guiding region111to the conductive region121is shortened, so that the uniformity of current distribution can be improved, and the polarization problem can be solved. Moreover, one conductive region121is provided to facilitate electrical connection of the tab12and the terminal1022. All of the above advantages can enhance the performance of the battery.

In some embodiments, as shown inFIGS.8and9, at least one of the first electrode plate1and the second electrode plate2is provided with a plurality of tabs12at intervals in a winding direction, so as to form a plurality of radially spaced conductive regions121at the end portion of the wound main body S.

In an extending direction of the winding axis K, one side of the main body portion11of at least one of the first electrode plate1and the second electrode plate2is provided with two or more tabs12at intervals, each tab12forms a conductive region121at the end portion of the wound main body S, and the conductive regions121and the liquid euiding regions111are alternately arranged at intervals in the radial direction. For example, the number of segments of the tabs12may not exceed10depending on the length of the electrode plate. In this embodiment of the present application, the electrolyte entering the interior of the wound main body S via the liquid guiding region111is allowed to simultaneously permeate into the conductive regions121on two sides, so that the electrolyte smoothly reaches the portions of the first electrode plate1and the second electrode plate2located in the conductive region121, and the infiltration performance of the electrolyte of the electrode assembly10is enhanced. Moreover, the electrons can simultaneously reach the conductive region121from an inner side and an outer side of the liquid guiding region111in the radial direction, so that the transmission distance of the electrons can be greatly shortened, the uniformity of current distribution can be improved, and the polarization problem can be solved; when the first electrode plate1and the second electrode plate2are longer after being unwound, the polarization problem caused by the long local transmission distance of the electrons can be better solved by designing segmented tabs12. Furthermore, by providing the plurality of conductive regions121, the overall length of the tab12provided in the radial direction can be increased to facilitate welding of the tab12and the adapter1025, and the tab is electrically connected to the terminal1022by means of the adapter1025. All of the above advantages can enhance the performance of the battery.

In some embodiments, as shown inFIG.8andFIG.9, two conductive regions121are provided and respectively located on the inner side and the outer side of the end portion of the wound main body S in the radial direction, and the liquid guiding region111is located between the two conductive regions121.

Due to different infiltration speeds of the electrode assembly10at different positions, for example, the electrolyte relatively easily infiltrates into the portions of the electrode assembly10closest to an inner ring and an outer ring; there is an electrolyte flow of a central tube in the inner ring, the outer ring is in contact with the electrolyte in the gap between the shell101and the electrode assembly10, so that the electrolyte more easily infiltrates into the inner and outer rings of the electrode assembly10than that into the middle region.

In this embodiment of the present application, the two conductive regions121are provided in a non-infiltration bottleneck region, for example, the inner ring and the outer ring of the electrode assembly10, so that the infiltration effect can be optimized, and the polarization problem can also be solved.

In some embodiments, as shown inFIGS.10and11, one conductive region121and one liquid guiding region111are respectively provided, and the conductive region121is located on the inner side of the conductive region111in the radial direction. For example, a radial width of the conductive region121may be greater than that of the liquid guiding region111so as to improve the overcurrent capability of the electrode assembly10.

In this embodiment of the present application, the conductive region121is provided on the inner side of the liquid guiding region111, and on the basis of ensuring an infiltration characteristic of the electrode assembly10by means of the liquid guiding region111, the tab12can also be prevented from being in contact with an inner wall of the shell101after the tab is flattened to form the bent portion, or the particles can be prevented from falling onto the inner side wall of the shell101when the tab12and the terminal1022are welded, so as to avoid short circuit and improve the working safety of the battery cell100.

In some embodiments, the liquid guiding regions111at the two ends of the wound main body S have the same radial dimension, and the conductive regions121at the two ends of the wound main body have the same radial dimension. The respective tabs12of the first electrode plate1and the second electrode plate2are led out of the two ends of the wound main body S, the two ends of the wound main body S are both provided with the conductive regions121and the liquid guiding regions111, and the “radial dimension” includes a radial position and a radial size.

In this embodiment of the present application, the two ends of the wound main body S are structurally symmetrical, so that the first electrode plate1and the second electrode plate2can be processed to have the same structure, the processing difficulty of the electrode assembly10can be reduced, and the production efficiency of the electrode assembly10can be increased.

In some other embodiments, the liquid guiding region111at one end of the wound main body S has the same radial dimension as the conductive region121at the other end. The respective tabs12of the first electrode plate1and the second electrode plate2are led out of the two ends of the wound main body S, the two ends of the wound main body S are both provided with the conductive regions121and the liquid guiding regions111, and the “radial dimension” includes a radial position and a radial size.

In this embodiment of the present application, the conductive regions121and the liquid guiding regions111at the two ends of the wound main body S are provided in a staggered manner in the radial direction, namely, the conductive region121at one end of the wound main body S corresponds to the liquid guiding region111at the other end, such that the wound main body S has the liquid guiding region111at any position in the radial direction, the electrolyte is allowed to enter the interior of the wound main body S more quickly and sufficiently, the distribution of the electrolyte in the interior of the electrode assembly10is more uniform, which makes the electrolyte uniformly react with the active materials on the first electrode plate1and the second electrode plate2during the charging and discharging of the battery, and the performance of the battery cell100is thus optimized.

In some embodiments, as shown inFIGS.6,8and10, the electrode assembly10further comprises a separator3, wherein the separator3is used for separating the first electrode plate1from the second electrode plate2; and the separator3, the main body portion11of the first electrode plate1and the main body portion of the second electrode plate2are wound to form a wound main body S; in the extending direction of the winding axis K, the portion of at least one side of the separator3located in the liquid guiding region111extends beyond a side edge of the main body portion11of the first electrode plate1and beyond a side edge of the main body portion11of the second electrode plate2.

The separator3may have an elongated strip-like structure in an unwound state, and the separator3may be made from a polypropylene (PP) material or a polyethylene (PE) material, and the interior thereof has micro or nano-scale pores for allowing metal ions to pass through during the charging and discharging of the battery.

Optionally, in the extending direction of the winding axis K, the portion of one side of the separator3located in the liquid guiding region111extends beyond the side edge of the main body portion11of the first electrode plate1and beyond the side edge of the main body portion11of the second electrode plate2; alternatively, as shown inFIG.13A, the portions of two sides of the separator3located in the liquid guiding region111extend beyond the side edge of the main body portion11of the first electrode plate1and beyond the side edge of the main body portion11of the second electrode plate2.

In this embodiment of the present application, the separator3is designed to be in a stepped shape and is widened in the liquid guiding region111, so that a side edge of the separator3extends outwards between the first electrode plate1and the second electrode plate2in the liquid guiding region111and is soaked in the electrolyte to allow the separator3to more easily absorb the electrolyte under a capillary action, the infiltration performance of the electrode assembly10is enhanced, and the performance of the battery cell100is thus enhanced. Optionally, as shown inFIG.12A, the separator3may also be designed to have an elongated equal-width structure.

In some embodiments, as shown inFIG.13A, the electrode assembly10further includes a separator3, wherein the separator3is used for separating the first electrode plate1from the second electrode plate2, and the main body portion11of at least one of the first electrode plate1and the second electrode plate2includes an active material region A and a flow guiding region B provided side by side in the extending direction of the winding axis K, the flow guiding region B being located on an outer side of the active material region A and used for guiding the electrolyte into the interior of the wound main body S; as shown inFIGS.17and18, a gap between the surface of the main body portion11located in the flow guiding region B and the separator3is greater than a gap between the surface of the main body portion11located in the active material region A and the separator3.

For example, the first electrode plate1is a positive electrode plate, and the active material region A is coated with a positive electrode active material, for example, the positive electrode active material may be a ternary material, lithium manganate or lithium iron phosphate; and the second electrode plate2is a negative electrode active material, which may be graphite or silicon.

In this embodiment of the present application, the gap between the surface of the main body portion11located in the flow guiding region B and the separator3is set to be greater than the gap between the surface of the main body portion11located in the active material region A and the separator3, so that a larger capillary gap can be formed between the flow guiding region B and the separator3, and after the electrolyte is absorbed into an end portion of the separator3, the electrolyte can rapidly enter the end portion of the wound main body S and then further enter the active material region A to react with the active material. This structure allows the gap between the main body portion11and the separator3to be gradually decreased from outside to inside, facilitating rapid entry of the electrolyte.

In some embodiments, as shown inFIG.12A, the flow guiding region B of at least one of the first electrode plate1and the second electrode plate2includes an infiltration region B1adjacent to the active material region A, with the gap between the surface of the main body portion11located in the infiltration region B1and the separator3being gradually increased from inside to outside in the extending direction of the winding axis K.

The infiltration region B1may have an elongated strip-like structure extending in the entire winding direction of the main body portion11and be used for introducing the electrolyte, and the width of the infiltration region B1in the extending direction of the winding axis K is smaller than that of the active material region A. As shown inFIGS.17and18, the surface of the infiltration region B1in the extending direction of the winding axis K may be an inclined plane, or may be designed to be in an arc shape, a stepped shape, etc., so long as the gap between the surface of the infiltration region B1and the separator3being gradually increased from inside to outside falls within the scope of protection of the present application.

In this embodiment of the present application, it is possible to introduce the electrolyte into the active material region A via the infiltration region B1after the electrolyte is absorbed at the end portion of the separator3, facilitating rapid entry of the electrolyte into the interior of the wound main body S for reaction.

In some embodiments, as shown inFIGS.17and18, the flow guiding region B of at least one of the first electrode plate1and the second electrode plate2includes the infiltration region B1adjacent to the active material region A. The main body portion11of at least one of the first electrode plate1and the second electrode plate2includes a current collector114, an active material layer112and an infiltration layer113, wherein the active material layer112is provided on a surface of the current collector114and located in the active material region A, the infiltration layer113is provided on the surface of the current collector114and located in the infiltration region B1, and the infiltration layer113has a higher liquid absorption capacity than the active material layer112.

The term “liquid absorption capacity” refers to the capability of a coating layer per unit area to absorb an electrolyte per unit time. For example, the first electrode plate1is a positive electrode plate and may use an aluminum foil as the current collector114, and the second electrode plate2is a negative electrode plate and may use a copper foil as the current collector114. For example, the infiltration layer113includes an inorganic ceramic coating, a high molecular polymer, and a binder. As shown inFIG.17, a side edge of the infiltration layer113is flush with a side edge of the current collector114, and the side edge of the separator3adjacent to the first electrode plate1extends beyond the side edges of the infiltration layer113and the current collector114.

In this embodiment of the present application, by coating the region of the main body portion11close to the outer side with the infiltration layer113having the higher liquid absorption capacity than the active material layer112, the capability of absorbing the electrolyte by the end portion of the wound main body S can be improved by using the material characteristic of the infiltration layer113so as to facilitate rapid absorption of the electrolyte into the interior of the wound main body S.

Moreover, the gap between the surface of the main body portion11located in the infiltration region B1and the separator3is gradually increased from inside to outside, namely, the thickness of the infiltration layer113is less than that of the active material layer112, and a gap gradually expanded from inside to outside is formed between the infiltration layer113and the separator3and also facilitates the absorption of the electrolyte. By improving both the structural design and material characteristic, the infiltration characteristic of the electrode assembly10can be better improved.

In some embodiments, as shown inFIGS.13A,14A,14B, and18, the flow guiding region B of at least one of the first electrode plate1and the second electrode plate2fiuther includes a guide region B2, wherein the region of the current collector114beyond the infiltration layer113in the extending direction of the winding axis K forms the guide region B2.

The guide region B2is a region of the current collector114beyond the infiltration layer113in the extending direction of the winding axis K, the region is not provided with a coating layer, and the portion of the current collector114located in the guide region B2is integrally connected to the tab12. The side edge of the separator3adjacent to the first electrode plate1is beyond the side edge of the current collector114such that the electrolyte is absorbed by means of the separator3and then enters the active material region A via the guide region B2and the infiltration region B1in sequence.

In this embodiment of the present application, the coating layer is not provided in the guide region B2, so that the gap between the current collector114and the separator3in the guide region B2is greater than the gap between the surface of the infiltration layer113and the separator3, and a multi-stage electrolyte absorption channel can be formed at the end portion of the wound main body S located in the liquid guiding region111. Also, the distance between the first electrode plate1or the second electrode plate2and the separator3is gradually decreased from the guide region B2, the infiltration region B1to the active material region A, so that the liquid absorption efficiency can be significantly increased, and the infiltration characteristic of the electrode assembly10can be improved, and thus the performance of the battery cell100can be enhanced.

In some embodiments, as shown mFIG.13A, the first electrode plate1is a positive electrode plate and is sequentially provided with an active material region A, an infiltration region B1and a guide region B2from inside to outside in the extending direction of the winding axis K; and as shown inFIG.13B, the second electrode plate2is a negative electrode plate and is sequentially provided with an active material region A and a guide region B2from inside to outside along the winding axis K.

In this embodiment of the present application, considering that the compaction density of the positive electrode plate is relatively high and the speed of the electrolyte entering the positive electrode plate is relatively low, the speed of the electrolyte permeating into the positive electrode active material can be increased by adding the infiltration region B1to the positive electrode plate; and the speed of the electrolyte entering the negative electrode plate is higher than that of the electrolyte entering the positive electrode plate, and by introducing the electrolyte only via the guide region B2, a manufacturing process of the negative electrode plate can be simplified. In this embodiment, the speeds of the electrolyte entering the positive electrode plate and the negative electrode plate can be similar, and the production difficulty of the electrode assembly10can also be reduced. Optionally, the first electrode plate1and the second electrode plate2may also be provided with the same structure, for example, the electrode plates are both provided with the infiltration region B1, or both not provided with the infiltration region B1.

In some embodiments, the side edge of the separator3located in the liquid guiding region111of at least one of the first electrode plate1and the second electrode plate2is located between an outer side edge of the flow guiding region B and an outer side edge of the tab12.

In this embodiment of the present application, the side edge of the separator3is provided beyond the outer side edge of the flow guiding region B, so that the extending portion of the separator3can be soaked in the electrolyte so as to absorb the electrolyte under the capillary action; also, the side edge of the separator3is not beyond the outer side edge of the tab12, so that excessive extension of the separator3in the conductive region121can be prevented from affecting the flattening of the tab12, and the conductive effect of the tab12can be ensured.

In some embodiments, as shown inFIGS.12A to16, the flow guiding region B is consistent with the active material region A in extension length in a circumferential direction of the wound main body S.

In this embodiment of the present application, the manufacturing difficulty of the electrode plate provided with the flow guiding region B can be reduced, and the flow guiding region is consistent with the active material region A in extension length, so that the electrolyte can be better guided to reach the active material region A over the whole coating length of the active material region A, the electrolyte can be uniformly distributed over the whole winding length of the electrode plate, and the performance of the battery cell100can be thus enhanced.

In part of the embodiment described above, the specific structure of the electrode plate is introduced by taking the first electrode plate1as an example, and the second electrode plate2may also use the same or similar structure.

Some specific embodiments will be given below to illustrate the structure of the electrode assembly10.

In a first embodiment, as shown inFIGS.6and7,FIG.6only shows a structure of one end of the battery cell100, and a structure of the other end may be symmetrical to one end embodied in the figures. The electrode assembly10is provided in the shell101, and the end portion of the shell101is provided with the opening1011and is closed by the end cap assembly102, the end cap assembly102including the end cap body1021, the terminal1022, the insulator1024and the adapter1025. The insulator1024is provided on the side of the end cap body1021close to the electrode assembly10, and the adapter1025is provided on the side of the insulator1024close to the electrode assembly10.

The electrode assembly10includes the first electrode plate1, the second electrode plate2and the separator3, wherein the first electrode plate1and the second electrode plate2are stacked, the separator3is used for separating the first electrode plate1from the second electrode plate2, and the first electrode plate1, the second electrode plate2and the separator3are wound together, so that the respective main body portions11of the first electrode plate1and the second electrode plate2form the wound main body S; and the end portion of the wound main body S is concentrically provided with one conductive region121and two liquid guiding regions111, and the conductive region121is located between the two liquid guiding regions111. The tab12is led out of the conductive region121and is wound by a plurality of turns, for example, six turns, and the tab12is flattened to form the bent portion, and is electrically connected to the terminal1022at the same end via the adapter1025. The tab12may be bent inwards in the radial direction to prevent the bent portion from touching the inner wall of the shell101and to facilitate reducing the radial dimension of the adapter1025.

In the conductive region121, the extension length of the first electrode plate1is the largest, followed by that of the separator3, and the second electrode plate2extends to a horizontal dotted line; and in the liquid guiding region111, the extension length of the separator3is the largest, the first electrode plate1and the second electrode plate2extend to the horizontal dotted line, and the first electrode plate1and the second electrode plate2are alternately provided.

As shown inFIG.6, an outer ring of the insulator1024is provided with a projection portion1024′ for spacing the tab12from the shell101so as to enhance the insulation performance. For example, the adapter1025may include a first connecting piece1025A and a second connecting piece1025B that are connected to each other, wherein the first connecting piece1025A is welded to the tab12, and the second connecting piece1025B is connected to the terminal1022.

In a second embodiment, as shown inFIGS.8and9, the difference from the first embodiment lies in that the end portion of the wound main body S is concentrically provided with two conductive regions121and one liquid guiding region111, and the liquid guiding region111is located between the two conductive regions121. The tab12of each conductive region121is continuously wound by a plurality of turns, for example, five turns.

In a third embodiment, as shown inFIGS.10and11, the difference from the first embodiment lies in that the end portion of the wound main body S is concentrically provided with one conductive region121and one liquid guiding region111, and the liquid guiding region111is located on the outer side of the conductive region121in the radial direction. For example, the radial width of the conductive region121is greater than that of the liquid guiding region111.

Some specific embodiments will be given below to illustrate the structures of the first electrode plate1, the second electrode plate2and the separator3that are unwound.

In the first embodiment, as shown inFIG.12A, the first electrode plate1is a positive electrode plate, the main body portion11of the first electrode plate1includes the active material region A and the infiltration region B1provided side by side in the extending direction of the winding axis K, and the infiltration region B1is located on the outer side of the active material region A. As shown inFIG.17, the current collector114may be coated with the active material layer112in the active material region A, and may be coated with the infiltration layer113in the infiltration region B1; the infiltration layer113may have a higher liquid absorption performance than the active material layer112; and the gap between the surface of the infiltration layer113and the separator3is gradually decreased from outside to inside and is larger than the gap between the active material layer112and the separator3. The side edge of the separator3may have a width W9beyond the side edge of the first electrode plate1.

The tab12projects from a side portion of the main body portion11in the extending direction of the wincing axis K, the tab12may be provided at a position close to one end of the main body portion11in the winding length, and after winding, the conductive region121may be located at the inner ring or the outer ring. The infiltration layer113extends in the entire winding length of the first electrode plate1, and the outer side edge of the infiltration layer113located in the conductive region121may have a small part of width on the tab12. A transitional portion122may be provided at the root portion of the tab12connected to the main body portion11, for example, at a fillet angle or a chamfer, so as to decrease a stress applied to the root portion when the tab12is flattened, and to prevent the tab12from cracking or being pulled. Optionally, the corner of the outer side edge of the tab12may also be provided with the transitional portion122. For example, a value of the fillet angle at the corner of the outer side edge of the tab12ranges from R3 to R12, and is preferably R8; and a value of the fillet angle at the connection to the main body portion11ranges from R1 to R8, and is preferably R5.

As shown inFIG.12B, the second electrode plate2is a negative electrode plate, the main body portion11of the second electrode plate2includes only the active material region A, and the tab12may be provided at the position close to one end of the main body portion11in the winding length.

As shown inFIG.12C, the separator3is in a rectangular elongated shape, and has an equal-width structure.

During winding, the respective tabs12of the first electrode plate1and the second electrode plate2are located on different sides in the extending direction of the winding axis K.

In the second embodiment, as shown inFIG.13A, the first electrode plate1is a positive electrode plate, and the main body portion11of the first electrode plate1includes the active material region A, the infiltration region B1, and the guide region B2provided side by side in the extending direction of the winding axis K, the infiltration region B1being located between the active material region A and the guide region B2. The infiltration region B1and the guide region B2extend in the entire winding length of the first electrode plate1.

As shown inFIG.18, the current collector114may be coated with the active material layer112in the active material region A, and may be coated with the infiltration layer113in the infiltration region B1; the infiltration layer113may have a higher liquid absorption performance than the active material layer112; and the gap between the surface of the infiltration layer113and the separator3is gradually decreased from outside to inside and is larger than the gap between the active material layer112and the separator3. The side edge of the separator3may have a width W9′ beyond the side edge of the guide region B2.

The tab12projects from the side portion of the main body portion11in the extending direction of the winding axis K, the tab12may be provided at one end of the main body portion11, and after winding, the conductive region121may be located at the inner ring or the outer ring.

As shown inFIG.13B, the second electrode plate2is a negative electrode plate, the main body portion11of the second electrode plate2includes the active material region A and the guide region B2, and the tab12may be provided at the position close to one end of the main body portion11in the winding length. The current collector114may be coated with the active material layer112in the active material region A, and the portion of the current collector114beyond the side edge of the active material region A forms the guide region B2.

As shown inFIG.13C, the width of the separator3in the conductive region121is represented by W0, and two side edges of the separator3are both widened in the liquid guiding region111by W1, such that the side edge of the separator3extends beyond the side edge of the main body portion11in the liquid guiding region111to facilitate absorption.

During winding, the respective tabs12of the first electrode plate1and the second electrode plate2are located on different sides in the extending direction of the winding axis K.

In the third embodiment, as shown inFIG.14A, the first electrode plate1is a positive electrode plate, and is structurally the same as that shown inFIG.13A. In the extending direction of the winding axis K, the active material region A has a width W4, the infiltration region B1has a width W3, the guide region B2has a width W2, and the tab12has a width W5.

As shown inFIG.14B, the second electrode plate2is a negative electrode plate, and is structurally the same as that shown inFIG.14A. In the extending direction of the winding axis K, the active material region A has a width W8, the infiltration region B1has a width W7, the guide region B2has a width W6, and the tab12has a width W9.

As shown inFIG.14C, the width of the separator3in the conductive region121is represented by W0, and two side edges of the separator3are both widened in the liquid guiding region111by W1, such that the side edge of the separator3extends beyond the side edge of the main body portion11in the liquid guiding region111to facilitate absorption. Optionally, the separator3may also use the equal-width structure shown inFIG.12C.

In some other embodiments, as shown inFIG.15, the first electrode plate1may be a positive electrode plate or a negative electrode plate, the main body portion11of the first electrode plate1includes the active material region A and the infiltration region B1provided side by side in the extending direction of the winding axis K, and the infiltration region B1is located on the outer side of the active material region A. The tab12may be located in the middle region of the main body portion11in the winding length, and after winding, the conductive region121is located in the middle region of the wound main body S in the radial direction.

In some other embodiments, as shown inFIG.16, the first electrode plate1may be a positive electrode plate or a negative electrode plate; and the difference thereof from that inFIG.15lies in that the side portion of the main body portion11in the extending direction of the winding axis K is provided with two tabs12, and the two tabs12are spaced apart from each other and respectively located at the positions close to the two ends of the main body portion11in the winding length. After winding, the end portion of the wound main body S is provided with two conductive regions121and one liquid guiding region111, and the liquid guiding region111is located between the two conductive regions121.

FIG.19is a schematic structural diagram of the first electrode plate1, the second electrode plate2and the separator3superimposed prior to winding according to some embodiments. For example, the first electrode plate1may be a negative electrode plate, the second electrode plate2is correspondingly a positive electrode plate, the first electrode plate1is longer than the second electrode plate2, and the separator3is longer than the first electrode plate1. The tabs12of the first electrode plate1and the second electrode plate2are opposite in a leading-out direction of the winding axis K, and are both located at the position of the main body portion11close to a first end in the winding direction, the first end refers to the left end, and the tabs12continuously extend in a partial winding length direction of the main body portion11.

The main body portion11of the first electrode plate1includes only an active material coating region A, the main body portion11of the second electrode plate2includes the active material region A and the infiltration region B1provided side by side in the extending direction of the winding axis K, and the infiltration region B1is located on the outer side of the active material region A. In the extending direction of the winding axis K, width edges on two sides of the active material coating region A of the first electrode plate1both exceed width edges of the corresponding sides of the active material coating region A of the second electrode plate2. The separator3uses an equal-width structure, and the two side edges of the separator3are both beyond the side edges of the main body portions11of the first electrode plate1and the second electrode plate2located on the same side, and are not beyond the outer side edges of the tabs12.

The above-mentioned specific embodiments only schematically show the structural forms and combination manners of the first electrode plate1, the second electrode plate2and the separator3, and different first electrode plates1, second electrode plates2and separators3may be combined according to requirements in an actual arrangement.

Also, the present application provides a manufacturing method for the electrode assembly10. As shown inFIG.20, in some embodiments, the manufacturing method includes:

S110, providing a first electrode plate1and a second electrode plate2that have opposite polarities, the first electrode plate1and the second electrode plate2each including a main body portion11and a tab12projecting from the main body portion11; and

S120, winding the first electrode plate1and the second electrode plate2about the winding axis K such that the respective main body portions11form a wound main body S, an end portion of the wound main body S including at least one conductive region121and at least one liquid guiding region111.

The tab12is led out of the conductive region121, is wound by at least one turn, and is used for electrical connection to the terminal1022of the battery cell100, and the liquid guiding region111is arranged adjacent to the conductive region121in a radial direction of the wound main body S and is used for guiding an electrolyte to flow into the interior of the wound main body S.

After the winding step S120, the tab12at the end portion of the wound main body S is flattened such that the tab12forms the bent portion to facilitate electrical connection to the terminal1022.

In the embodiment of the present application, the end portion of the wound main body S simultaneously has the conductive region121and the liquid guiding region111. Since no tab12is provided in the liquid guiding region111, after the tab12of the conductive region121is flattened, the electrolyte in the battery cell100also easily flows into the interior of the wound main body S through the gap between the first electrode plate1and the second electrode plate2in the liquid guiding region111, ensuring the infiltration performance of the electrode assembly10, so that the electrolyte can sufficiently react with the active materials on the first electrode plate1and the second electrode plate2during charging and discharging of the battery, and the performance of the battery cell100is thus optimized.

Furthermore, since the tab12extends continuously and is wound by at least one turn in the conductive region121, the tab has better connection strength with the main body portion11in a circumferential direction, such that a root portion of the tab12has a better self-supporting effect, a crumpling phenomenon of the tab12is prevented in the process of flattening the tab12by applying a circiunferential acting force, the shape of a flattened region is stabilized, the effect of welding the tab12and the terminal1022is optimized, it is ensured that the electrode assembly10reliably transmits electric energy outwards, and the overcunent capacity is improved. In addition, particles generated during welding of the tab12are less prone to dropping between the first electrode plate1and the second electrode plate2of the liquid guiding region111in the circumferential direction, so that the working reliability of the electrode assembly10can be improved.

Finally, the present application provides a manufacturing apparatus400for the electrode assembly10. As shown inFIG.21, in some embodiments, the manufacturing apparatus400includes: an electrode plate providing device410and an electrode plate winding device420. The electrode plate providing device410is configured to provide a first electrode plate1and a second electrode plate2that have opposite polarities, the first electrode plate1and the second electrode plate2each including a main body portion11and a tab12projecting from the main body portion11; and the electrode plate winding device420is configured to wind the first electrode plate1and the second electrode plate2about the winding axis K such that the respective main body portions11form a wound main body S, an end portion of the wound main body S including at least one conductive region121and at least one liquid guiding region111. The tab12is led out of the conductive region121, is wound by at least one turn, and is used for electrical connection to the terminal1022of the battery cell100, and the liquid guiding region111is arranged adjacent to the conductive region121in a radial direction of the wound main body S and is used for guiding an electrolyte to flow into the interior of the wound main body S.

The manufacturing apparatus400of this embodiment of the present application has the same technical effect as the manufacturing method.

Although the present application is described with reference to the preferred embodiments, various improvements may be made thereto, and the components thereof may be replaced with equivalents, without departing from the scope of the present application. In particular, the technical features mentioned in the embodiments can be combined in any manner as long as there is no structural conflict. The present application is not limited to specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.