CN116404272A

CN116404272A - Bare cell, energy storage device and electric equipment

Info

Publication number: CN116404272A
Application number: CN202310635167.4A
Authority: CN
Inventors: 周文扬; 熊永锋
Original assignee: Shenzhen Haichen Energy Storage Control Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Current assignee: Shenzhen Haichen Energy Storage Control Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Priority date: 2023-05-31
Filing date: 2023-05-31
Publication date: 2023-07-07

Abstract

The application provides a bare cell, an energy storage device and electric equipment. The bare cell comprises a positive pole piece, a diaphragm and a negative pole piece, and the diaphragm is clamped between the positive pole piece and the negative pole piece. The positive electrode plate comprises a first current collector and a first active material layer, the first current collector comprises a first coating area and a first tab area, and the first active material layer is arranged in the first coating area; the negative electrode plate comprises a second current collector and a second active material layer, the second current collector comprises a second coating area and a second lug area, and the second active material layer is arranged in the second coating area; the first tab region is spaced apart from the second active material in a direction in which the first coating region faces the first tab region. According to the technical scheme, the energy storage device using the bare cell can be prevented from being invalid due to the fact that the anode contacts with the cathode are short-circuited, and the service life of the energy storage device is prolonged.

Description

Bare cell, energy storage device and electric equipment

Technical Field

The application relates to the field of energy storage, in particular to a bare cell, an energy storage device and electric equipment.

Background

In the case of a short circuit inside a battery cell, the battery cell generates a large amount of heat and gas in a short time, resulting in a fire explosion of the battery cell, and the short circuit inside the battery cell is generally caused by a contact short circuit between the positive and negative electrodes of the winding core inside the battery cell. How to avoid the failure of the energy storage device applying the winding core caused by the short circuit of the positive electrode and the negative electrode of the winding core is a long-term searching subject in the industry.

Disclosure of Invention

The embodiment of the application provides a naked electric core, energy storage device and consumer, can avoid leading to using the energy storage device of rolling up the core to become invalid because of rolling up the positive negative pole contact short circuit of core, improves energy storage device's life.

In a first aspect, the present application provides a bare cell, where the bare cell includes a positive electrode plate, a diaphragm, and a negative electrode plate, where the diaphragm is sandwiched between the positive electrode plate and the negative electrode plate;

the positive electrode plate comprises a first current collector and a first active material layer, the first current collector comprises a first coating area and a first tab area, and the first active material layer is arranged in the first coating area;

the negative electrode plate comprises a second current collector and a second active material layer, the second current collector comprises a second coating area and a second lug area, and the second active material layer is arranged in the second coating area;

the first tab region is spaced apart from the second active material layer in a direction in which the first coating region faces the first tab region.

It is understood that, in the case where a short circuit occurs inside the battery cell, the battery cell generates a large amount of heat and gas in a short time, thereby causing the battery cell to catch fire and explode. The internal short circuit inside the battery cell is caused by the short circuit caused by the contact of the positive electrode current collector and the negative electrode active material of the winding core inside the battery cell, and the short circuit has small internal resistance, large area and quick diffusion, so that the short circuit current is large, the short circuit time is long, the short circuit reaction is severe, and the ignition and explosion of the battery cell are easily caused.

Therefore, the first tab area is a risk area in the first current collector, which is easy to pierce through the separator in the die cutting and cutting process of the first tab, so that the first current collector is in contact with the second active material layer to be short-circuited. Through the dislocation arrangement of the area and the second active material layer, the whole position of the first tab area can be higher than the position of the second active material layer in the direction of the first coating area towards the first tab area, so that the first tab area and the second active material layer can not be arranged right opposite to each other, the short circuit phenomenon of the first current collector and the second active material layer caused by the fact that the separator is pierced is further reduced, and the reliability is good.

In a possible embodiment, the first current collector further includes a tab void region connected between the first coating region and the first tab region, and the tab void region is spaced apart from the first active material layer in a direction in which the first coating region faces the first tab region.

That is, the orthographic projection of the first active material layer on the diaphragm and the orthographic projection of the tab blank area on the diaphragm are arranged in a staggered manner. Under this setting, the utmost point ear blank zone is the uncoated district that does not have active material in the first electric current collector to can form the uncoated district in the first electric current collector together with first utmost point ear district, increase the regional area of uncoated active material in the first electric current collector, avoid leading to positive negative pole to switch on because of welding the high temperature burns through the diaphragm in the welding process, reduce the inside positive negative circuit risk of naked electric core.

In a possible embodiment, at least part of the tab recess is arranged opposite the second active material layer in the direction of the first coating region toward the first tab region.

That is, the orthographic projection of at least part of the tab blank area on the separator falls within the range of orthographic projection of the second active material layer on the separator. Under this setting, can regard as the middle zone between connection first utmost point ear district and the first coating district with utmost point ear blank district, and utmost point ear blank district is difficult for cutting the comparatively safe region of penetrating the diaphragm at first utmost point ear cross cutting in-process again. Therefore, when the first tab area is connected with the first tab, the tab blank area and the negative electrode active material are arranged right opposite to each other, so that the risk of conducting the positive electrode current collector (first current collector) and the negative electrode active material due to the fact that a large number of particles such as burrs and beads are generated in the die cutting process of the first tab to pierce through a diaphragm can be reduced, and the risk of short-circuiting of the positive electrode and the negative electrode inside the bare cell is further reduced.

In a possible embodiment, the ratio of the width L1 of the tab blank to the width L of the first current collector is between 0.02 and 0.04.

It will be appreciated that if the aforementioned ratio is too large, the size of the tab space occupying the first current collector is too large, resulting in an increase in manufacturing cost. If the proportion is too small, short circuit risks still exist when the offset of the positive pole piece, the diaphragm and the negative pole piece is large in the winding process. In the size range, the film width of the tab blank area is matched with the total width of the first current collector, so that the problem of short circuit of the bare cell is avoided, raw materials are prevented from being wasted, and the manufacturing cost is reduced.

In a possible embodiment, the thickness H of the first tab region is between 8um and 18 um.

It can be understood that, in the die cutting process of the first tab, burrs generated easily pierce the separator to cause the contact short circuit between the positive electrode current collector and the negative electrode active material, in order to avoid the occurrence of the foregoing failure condition of the short circuit in the bare cell, an edge coating with an insulating effect is usually sprayed on the junction between the first tab area and the first coating area, so as to prevent the occurrence of the internal short circuit at the junction. The insulating coating sprayed on the junction of the first tab area and the first coating area is affected by the fluidity of the spraying slurry, which often results in the contact of part of the insulating layer and the active material, resulting in the increase of the impedance polarization of the active material on the film surface of the positive electrode near the tab, and further the capacity of the area cannot be fully exerted, and the produced energy storage battery has low capacity. And through setting up the utmost point ear blank district between first utmost point ear district and first coating district, can make utmost point ear blank district regard as transition district and first utmost point ear district direct link to each other, thereby avoid first utmost point ear district because of directly linking to each other with first coating district take place the problem emergence of internal short circuit in juncture, practiced thrift the cost of extra coating insulating coating, reduce insulating coating electrolyte corrosion resistance, the risk such as inefficacy, drop that the adhesion strength descends and bring, the reliability is good.

In one possible embodiment, the width W1 of the first active material layer, the width W2 of the second active material layer, and the width W3 of the separator satisfy the relationship: w1 is less than W2 and less than W3.

It is understood that, due to production accuracy such as pole piece dimensional accuracy, winding accuracy, etc., there is a risk of positional deviation in the direction of the first coating region toward the first tab region when the positive pole piece, the negative pole piece, and the separator are wound. If the end part of the negative electrode plate in the direction of the first coating area facing the first tab area exceeds the end part of the positive electrode plate, the lithium precipitation phenomenon can occur in the charging and discharging process of the energy storage device; if the end of the separator in the direction of the first coating region toward the first tab region is dislocated, the positive electrode sheet and the negative electrode sheet are likely to be in direct contact to cause short circuit. Therefore, in the embodiment of the application, the width of the first active material layer is smaller than the width W2 of the second active material layer, the width W2 of the second active material layer is smaller than the width W3 of the diaphragm, the film widths of the positive electrode plate and the negative electrode plate can be relatively close, the lithium precipitation problem is avoided, the safe operation of the bare cell is ensured, and meanwhile, the film widths of the positive electrode plate and the negative electrode plate are matched with each other, so that the manufacturing cost can be reduced.

In one possible embodiment, the width W1 of the first active material layer, the width W2 of the second active material layer, the width W3 of the separator, and the width L1 of the tab void region satisfy the relationship: w2 < W1+L1X2 < W3.

With the arrangement, the facing area of the first tab area and the second active material layer can be reduced, and the internal short circuit phenomenon of the positive electrode current collector and the negative electrode active material can be effectively avoided.

In one possible embodiment, the length of the negative electrode tab is greater than the length of the positive electrode tab.

In one possible embodiment, the bare cell includes a first end and a second end;

the first tab area and the second tab area are both positioned at the first end or the second end; or alternatively, the process may be performed,

the first tab region is located at one of the first end and the second end, and the second tab region is located at the other of the first end and the second end.

That is, in the height direction of the winding core, the first tab and the second tab may be located on the same side of the winding core, or the first tab and the second tab may be located on different sides of the winding core. When the first lug and the second lug are positioned on the same side of the winding core, the single side of the winding core is provided with the lug, the first lug on one side is electrically connected with the first pole piece, and the second lug on the same side is connected with the negative pole piece, so that the pole piece is prepared. When the first tab and the second tab are positioned on different sides of the winding core, the tabs are arranged on two sides of the winding core, one side of the winding core is connected with the first tab, the other side of the winding core is connected with the second tab, and when the battery is prepared, the contact between the positive tab and the negative tab is avoided, so that the battery is prepared.

In a second aspect, the present application also provides an energy storage device comprising an end cap assembly and a bare cell as described above, the bare cell being electrically connected to the end cap assembly.

In a third aspect, the present application further provides a powered device, including an energy storage device as described above, where the energy storage device is configured to provide power for the powered device.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained by those skilled in the art without the inventive effort.

FIG. 1 is a schematic diagram of a household energy storage system provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of an electric device according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a structure of the energy storage device shown in FIG. 1;

FIG. 4 is an exploded schematic view of the energy storage device shown in FIG. 3;

FIG. 5 is a schematic diagram of the battery cell of the energy storage device shown in FIG. 4;

FIG. 6 is a schematic view of a structure of the bare cell of FIG. 5 when it is not being wound;

fig. 7 is another structural schematic of the bare cell shown in fig. 5 when not wound;

fig. 8 is a schematic view of still another structure of the bare cell shown in fig. 5 when it is not wound;

fig. 9 is a schematic view of the bare cell shown in fig. 7 at another angle.

Reference numerals:

the household energy storage system 400, the electric energy conversion device 410, the first user load 420, the second user load 430, the electric device 300, the power system 310, the energy storage device 200, the housing 210, the cell assembly 220, the end cap assembly 230, the cell 100, the bare cell 40, the first tab 50, the second tab 60, the positive electrode tab 10, the negative electrode tab 20, the separator 30, the first current collector 11, the first active material layer 12, the first surface 111, the second surface 112, the first coating area 113, the tab blank 114, the first tab area 115, the second current collector 21, the third surface 211, the fourth surface 212, the second active material layer 22, the second coating area 213, the second tab area 214, the first end 101, and the second end 102.

Detailed Description

For ease of understanding, the terms involved in the embodiments of the present application are explained first.

And/or: merely one association relationship describing the associated object, the representation may have three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone.

A plurality of: refers to two or more.

And (3) connection: it is to be understood in a broad sense that, for example, a is linked to B either directly or indirectly via an intermediary.

The following description of the embodiments of the present application will be made with reference to the accompanying drawings.

Because of the strong timeliness and space properties of energy required by people, in order to reasonably utilize the energy and improve the utilization rate of the energy, one energy form needs to be stored by one medium or equipment and then converted into another energy form, and the energy is released in a specific energy form based on future application. At present, the main way of generating green electric energy is to develop green energy sources such as photovoltaic, wind power and the like to replace fossil energy sources.

At present, the generation of green electric energy generally depends on photovoltaic, wind power, water potential and the like, but wind energy, solar energy and the like generally have the problems of strong intermittence and large fluctuation, which can cause unstable power grid, insufficient peak electricity consumption, too much electricity consumption and unstable voltage can cause damage to the electric power, so that the problem of 'wind abandoning and light abandoning' possibly occurs due to insufficient electricity consumption requirement or insufficient power grid acceptance, and the problem needs to be solved by relying on energy storage. The energy is converted into other forms of energy through physical or chemical means and is stored, the energy is converted into electric energy when needed and released, in short, the energy storage is similar to a large-scale 'charge pal', the electric energy is stored when the photovoltaic and wind energy are sufficient, and the stored electric power is released when needed.

Taking electrochemical energy storage as an example, the scheme provides an energy storage device, wherein a group of chemical batteries are arranged in the energy storage device, chemical elements in the chemical batteries are mainly used as energy storage media, and the charge and discharge process is accompanied with chemical reaction or change of the energy storage media.

The existing energy storage (i.e. energy storage) application scene is wider, including aspects such as power generation side energy storage, electric network side energy storage, renewable energy grid-connected energy storage, user side energy storage and the like, the types of corresponding energy storage devices include:

(1) The large energy storage container applied to the energy storage scene at the power grid side can be used as a high-quality active and reactive power regulation power supply in the power grid, so that the load matching of electric energy in time and space is realized, the renewable energy consumption capability is enhanced, and the large energy storage container has great significance in the aspects of standby of a power grid system, relieving peak load power supply pressure and peak regulation and frequency modulation.

(2) The main operation modes of the small and medium-sized energy storage electric cabinet applied to the industrial and commercial energy storage scenes (banks, shops and the like) at the user side and the household small-sized energy storage box applied to the household energy storage scene at the user side are peak clipping and valley filling. Because of the large price difference of the electricity charge at the peak-valley position according to the electricity consumption requirement, after the energy storage equipment is arranged by a user, in order to reduce the cost, the energy storage cabinet/box is charged usually in the electricity price valley period; and in the peak period of electricity price, the electricity in the energy storage equipment is released for use, so that the purpose of saving electricity charge is achieved. In addition, in remote areas and areas with high occurrence of natural disasters such as earthquake, hurricane and the like, the household energy storage device is equivalent to the fact that a user provides a standby power supply for the user and the power grid, and inconvenience caused by frequent power failure due to disasters or other reasons is avoided.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a household energy storage system 400 according to an embodiment of the present application. In this embodiment, a household energy storage scenario in the user side energy storage is taken as an example for illustration, and the energy storage device 200 is not limited to the household energy storage scenario.

The application provides a household energy storage system 400, the household energy storage system 400 includes an electric energy conversion device 410 (photovoltaic panel), a first user load 420 (street lamp), a second user load 430 (household appliance), and the like, and an energy storage device 200, wherein the energy storage device 200 is a small-sized energy storage box, and can be installed on an outdoor wall in a wall hanging manner. In particular, the photovoltaic panel may convert solar energy into electric energy during low electricity price periods, and the energy storage device 200 is used to store the electric energy and supply the electric energy to street lamps and household appliances for use during electricity price peaks or to supply power during power outage/power outage of the power grid.

Referring to fig. 2, fig. 2 is a schematic structural diagram of an electric device 300 according to an embodiment of the present application. Powered device 300 includes power system 310 and energy storage device 200. The power system 310 is electrically connected to the energy storage device 200. The energy storage device 200 provides a source of power for the power system 310.

In the following, the electric device 300 is taken as an example of an automobile, and the automobile may be a fuel oil automobile, a gas automobile or a new energy automobile, and the new energy automobile may be a pure electric automobile, a hybrid electric automobile or a range-extended automobile. The automobile includes a battery, a controller, and a motor. The battery is used to supply power to the controller and motor as an operating power source and a driving power source for the automobile, for example, the battery is used for the power consumption for operation at the time of starting, navigation, and running of the automobile. For example, the battery supplies power to the controller, the controller controls the battery to supply power to the motor, and the motor receives and uses the power of the battery as a driving power source for the automobile to supply driving power to the automobile instead of or in part instead of fuel oil or natural gas.

It should be noted that, the automobile is only one usage scenario of the energy storage device 200 provided in the present application, and in other scenarios, the energy storage device 200 may also be used in other electronic devices or mechanical devices, etc., and the usage scenario of the energy storage device 200 is not specifically limited in the present application.

Referring to fig. 3 and 4 in combination, fig. 3 is a schematic structural diagram of the energy storage device 200 shown in fig. 1, and fig. 4 is an exploded schematic diagram of the energy storage device 200 shown in fig. 3. The energy storage device 200 illustrated in fig. 3-4 is merely one configuration of the energy storage device 200, and should not be construed as limiting the energy storage device 200 provided in the embodiments of the present application.

It is understood that the energy storage device 200 may include, but is not limited to, a battery cell, a battery module, a battery pack, a battery system, etc. As shown in fig. 3, when the energy storage device 200 is a single battery, it may be a square battery. When the energy storage device 200 includes a plurality of batteries, the plurality of batteries are electrically connected and are all located inside the housing of the energy storage device 200, which can be protected from the external environment by the housing. Illustratively, a plurality of cells are arranged at intervals. The plurality of batteries may be connected in series, or in parallel, or a mixture of series and parallel to achieve a larger capacity and power.

The energy storage device 200 is exemplified as a square battery, but it should be understood that the energy storage device 200 is not limited thereto.

Referring to fig. 3 and 4 in combination, fig. 4 is an exploded view of the energy storage device shown in fig. 3. The energy storage device 200 may include a housing 210, a cell assembly 220, and an end cap assembly 230. An opening is provided at one end of the housing 210, the battery cell assembly 220 is mounted inside the housing 210, and the end cap assembly 230 is connected to the opening of the housing 210 and cooperates with the housing 210 to encapsulate the battery cell assembly 220. The end cap assembly 230 is electrically connected to the cell assembly 220 to effect extraction of the battery electrodes. Illustratively, the housing 210 is a metal housing 210, such as an aluminum housing. Of course, the housing 210 may be made of other materials.

It should be noted that fig. 3-4 are only for illustrative purposes to describe the connection relationship between the housing 210 and the end cap assembly 230, and are not intended to limit the connection location, specific configuration and number of the respective devices. The structure illustrated in the embodiments of the present application does not constitute a specific limitation on the energy storage device 200. In other embodiments of the present application, the energy storage device 200 includes more or fewer components than those shown in fig. 3-4, or certain components may be combined, certain components may be split, or different arrangements of components may be provided. The components shown in fig. 3-4 may be implemented in hardware, software, or a combination of software and hardware.

Referring to fig. 4, the battery cell assembly 220 may include a plurality of battery cells 100, and the plurality of battery cells 100 are disposed in parallel. The battery capacity of the energy storage device 200 can be increased by arranging the plurality of battery cells 100, so that the battery can be used for a long time, and the application scene of the battery is further increased. For example, the number of the battery cells 100 may be four, and the four battery cells 100 are arranged in a group.

The specific structure of one cell 100 will be described in detail below, and the structural improvement of the cell 100 can be applied to other cells 100 without conflict.

Referring to fig. 5 and fig. 6 in combination, fig. 5 is a schematic structural diagram of the battery cell 100 of the energy storage device 200 shown in fig. 4, and fig. 6 is a schematic structural diagram of the bare cell 40 shown in fig. 5 when the bare cell is not wound. The X direction is a winding direction of the bare cell 40.

The battery cell 100 may include a bare cell 40, a first tab 50 and a second tab 60, the first tab 50 and the second tab 60 being connected to the bare cell 40. The first tab 50 and the second tab 60 have opposite polarities, one being a positive tab and the other being a negative tab. The first tab 50 is taken as a positive tab, and the second tab 60 is taken as a negative tab, but it should be understood that the present invention is not limited thereto.

The bare cell 40 may include a positive electrode tab 10, a negative electrode tab 20, and a separator 30, the separator 30 being interposed between the positive electrode tab 10 and the negative electrode tab 20, the positive electrode tab 10 being electrically connected to the first tab 50, the negative electrode tab 20 being electrically connected to the second tab 60. The positive electrode sheet 10, the separator 30, and the negative electrode sheet 20 are sequentially laminated to form a laminated structure, the bare cell 40 is formed by winding the laminated structure, the portion of the positive electrode sheet 10 extending out of the bare cell 40 may form the first tab 50, and the portion of the negative electrode sheet 20 extending out of the bare cell 40 may form the second tab 60. The separator 30 may be a base film made of an insulating material, has light weight and good tensile property, and may be well connected with the positive electrode sheet 10 and the negative electrode sheet 20. Illustratively, the material of the diaphragm 30 may be a polymeric insulating layer, such as: films of polystyrene, polypropylene, polyester, polycarbonate, polytetrafluoroethylene, polyimide, and the like; the material of the separator 30 may be synthetic fiber insulating paper, for example: aromatic polyamide fiber paper and polyester fiber paper; the material of the separator 30 may be various insulating tapes or the like.

Illustratively, the positive electrode sheet 10, the negative electrode sheet 20, and the separator 30 may be wound in parallel to the X direction, the separator 30 (in the X direction) may have a length greater than that of the positive electrode sheet 10 (in the X direction) and the negative electrode sheet 20 (in the X direction), and the negative electrode sheet 20 (in the X direction) may have a length greater than that of the positive electrode sheet 10 (in the X direction). Through both ends (along X direction) with diaphragm 30 all surpass the both ends of anodal pole piece 10 and negative pole piece 20, and diaphragm 30 locates between anodal pole piece 10 and the negative pole piece 20, even take place the skew at coiling in-process anodal pole piece 10, negative pole piece 20 or diaphragm 30, also can greatly reduced anodal pole piece 10 and negative pole piece 20 contact's risk, improves energy storage device 200's security performance and life.

Referring to fig. 7 and 8 in combination, fig. 7 is another schematic structural view of the bare cell 40 shown in fig. 5 when not being wound, and fig. 8 is another schematic structural view of the bare cell 40 shown in fig. 5 when not being wound. The positive electrode tab 10 may include a first current collector 11 and a first active material layer 12, the first active material layer 12 being stacked with the first current collector 11.

The first current collector 11 may include a first surface 111 and a second surface 112 disposed opposite to each other, where the first surface 111 is a surface of the first current collector 11 facing the separator 30, and the second surface 112 is a surface of the first current collector 11 facing away from the separator 30. The first current collector 11 may include a first coating region 113, a tab blank region 114, and a first tab region 115, the tab blank region 114 being connected between the first coating region 113 and the first tab region 115. The first coating region 113 is a region of the first current collector 11 connected to the first active material layer 12, the tab blank region 114 is a region of the first current collector 11 not coated with the active material, and the first tab region 115 is a region of the first current collector 11 not coated with the active material and connected to the first tab 50. In other words, the first coating region 113 is a region in the first current collector 11 where the active material is coated, and the tab blank region 114 and the first tab region 115 are regions in the first current collector 11 where the active material is not coated. The material of the first current collector 11 may be aluminum, for example.

Thus, by providing the tab blank 114 between the first tab region 115 and the first coating region 113, the tab blank 114 can be used as a transition region between the first tab region 115 and the first coating region 113. When the first tab region 115 is connected with the first tab 50, the tab blank region 114 without the anode active material is connected to the edge of the first tab region 115 and the edge of the first coating region 113, so that the tab blank region 114 and the cathode active material are correspondingly arranged, the facing area of the first tab region 115 and the cathode active material is reduced, and the risk of conducting the anode current collector (the first current collector 11) and the cathode active material due to piercing the diaphragm 30 by a large amount of particles such as burrs and beads generated in the die cutting process of the first tab 50 is reduced, the risk of short-circuiting the anode and the cathode of the battery cell 100 is further reduced, and the short-circuiting of the anode and the cathode of the energy storage device 200 is avoided to a certain extent.

In one possible embodiment, the ratio of the width L1 of the tab void region 114 to the width L of the first current collector 11 is between 0.02 and 0.04 (including the end points 0.02 and 0.04). It will be appreciated that if the aforementioned ratio is excessively large, the tab space 114 occupies the first current collector 11 in an excessively large size, resulting in an increase in manufacturing costs. If the aforementioned ratio is too small, there is still a risk of short circuit during winding when the amounts of deflection of the positive electrode tab 10, the separator 30, and the negative electrode tab 20 are large. In the above size range, the film width of the tab void region 114 and the total width of the first current collector 11 cooperate to ensure that the cell 100 does not have a short circuit problem, and at the same time, the waste of raw materials can be avoided, thereby reducing the manufacturing cost.

In one possible embodiment, the thickness of the first tab region 115 may be between 8um and 18um (including the end points 8um and 18 um). It will be appreciated that, during the die cutting process of the first tab 50, burrs generated easily pierce the separator 30 to cause the contact short between the positive electrode current collector and the negative electrode active material, and in order to avoid the foregoing occurrence of the short circuit failure condition in the battery cell 100, an edge coating with an insulating effect is typically sprayed on the junction between the first tab region 115 and the first coating region 113, so as to prevent the occurrence of the internal short circuit at that location. The insulating coating sprayed on the junction of the first tab region 115 and the first coating region 113 is affected by the fluidity of the spraying slurry, which often results in the contact between a part of the insulating layer and the active material, resulting in the increase of the impedance polarization of the active material on the film surface of the positive electrode near the tab, and thus the capacity of the region cannot be fully exerted, and the capacity of the manufactured energy storage battery is low. By arranging the tab blank region 114 between the first tab region 115 and the first coating region 113, the tab blank region 114 can be directly connected with the first tab region 115 as a transition region, so that the problem that the first tab region 115 is directly connected with the first coating region 113 to cause internal short circuit at the junction is avoided, the cost of additionally coating an insulating coating is saved, and risks of failure, falling and the like caused by electrolyte corrosion resistance and adhesive force reduction of the insulating coating are reduced, so that the reliability is good.

Referring to fig. 7 and 8 in combination, the first active material layer 12 is laminated and connected to the first current collector 11. The first active material layer 12 is disposed at a distance from the tab void region 114 in the direction (X direction) in which the first coating region 113 faces the first tab region 115. That is, the front projection of the first active material layer 12 on the separator 30 is offset from the front projection of the tab space 114 on the separator 30. In this arrangement, the tab blank area 114 is an uncoated area of the first current collector 11, which is not coated with an active material, so that the uncoated area of the first current collector 11 can be formed together with the first tab area 115, the area of the uncoated active material area of the first current collector 11 is increased, the conduction of the positive electrode and the negative electrode due to the burning through of the separator 30 caused by the too high welding temperature in the welding process is avoided, and the risk of short circuit of the positive electrode and the negative electrode in the battery cell 100 is reduced.

In one possible application scenario, as shown in fig. 7, the number of first active material layers 12 is one, the first active material layers 12 are disposed on the first surface 111 of the first current collector 11, and the first active material layers 12 are disposed on the first coating region 113 of the first current collector 11.

In another possible application scenario, as shown in fig. 8, the number of the second active material layers 22 is two, the two second active material layers 22 are respectively disposed on the first surface 111 and the second surface 112 of the first current collector 11, and the two first active material layers 12 are both disposed in the first coating region 113 of the first current collector 11.

Referring to fig. 7 and 8 in combination, the negative electrode tab 20 may include a second current collector 21 and a second active material layer 22, and the second active material layer 22 is stacked with the second current collector 21.

The second current collector 21 may include a third surface 211 and a fourth surface 212 disposed opposite to each other, where the third surface 211 is a surface of the second current collector 21 facing the separator 30, and the fourth surface 212 is a surface of the second current collector 21 facing away from the separator 30. The second current collector 21 may include a second coating region 213 and a second tab region 214, the second tab region 214 being connected to one side of the second coating region 213. The second coating region 213 is a region of the second current collector 21 connected to the second active material layer 22, and the second tab region 214 is a region of the second current collector 21 not coated with the active material and connected to the second tab 60. In other words, the second coating region 213 is a region of the second current collector 21 coated with the active material, and the second tab region 214 is a region of the second current collector 21 not coated with the active material. Illustratively, the material of the second current collector 21 may be copper or nickel.

The second active material layer 22 is laminated and connected to the second current collector 21, and the second active material layer 22 and the first active material layer 12 are respectively located on opposite sides of the separator 30. The second active material layer 22 is disposed offset from the second tab region 214 in the direction (X direction) in which the second coating region 213 faces the second tab region 214. That is, the orthographic projection of the second active material layer 22 on the diaphragm 30 is offset from the orthographic projection of the second tab area 214 on the diaphragm 30. In this arrangement, the second tab region 214 is an uncoated region of the second current collector 21 that is not coated with active material.

In one possible application scenario, as shown in fig. 7, the number of the second active material layers 22 is one, the second active material layers 22 are disposed on the third surface 211 of the second current collector 21, and the second active material layers 22 are disposed on the second coating region 213 of the second current collector 21.

In another possible application scenario, as shown in fig. 8, the number of the second active material layers 22 is two, the two second active material layers 22 are respectively disposed on the third surface 211 and the fourth surface 212 of the second current collector 21, and the two second active material layers 22 are both disposed in the second coating region 213 of the second current collector 21.

Referring to fig. 7, in a direction (X direction) in which the first coating region 113 faces the first tab region 115, the first tab region 115 is spaced apart from the second active material. That is, the orthographic projection of the second active material layer 22 on the separator 30 is offset from the orthographic projection of the first tab region 115 on the separator 30. It will be appreciated that the first tab region 115 is a risk area in the first current collector 11 that is prone to puncture through the separator 30 during die cutting of the first tab 50, thereby resulting in shorting of the first current collector 11 to the second active material layer 22. By disposing the region and the second active material layer 22 in a staggered manner, the entire position of the first tab region 115 can be made higher than the position of the second active material layer 22 in the X direction, so that the first tab region 115 and the second active material layer 22 are not disposed in a facing manner, and the occurrence of the short circuit phenomenon between the first current collector 11 and the second active material layer 22 due to the penetration of the separator 30 can be further reduced, and the reliability is improved.

Referring to fig. 7 and 9 in combination, fig. 9 is a schematic view illustrating another angle of the bare cell 40 shown in fig. 7. The X direction is a winding direction of the bare cell 40, and the Z direction is a height direction of the bare cell 40.

At least a part of the tab void region 114 is disposed opposite to the second active material layer 22 in a direction (X direction) in which the first coating region 113 faces the first tab region 115. That is, the orthographic projection of at least a portion of the tab void region 114 onto the separator 30 falls within the orthographic projection of the second active material layer 22 onto the separator 30. With this arrangement, the tab clearance 114 can be used as an intermediate area between the first tab area 115 and the first coating area 113, and the tab clearance 114 is a safer area that is not prone to puncturing the diaphragm 30 during die cutting of the first tab 50. Therefore, when the first tab region 115 is connected to the first tab 50, the tab blank region 114 is disposed opposite to the negative electrode active material, so that the risk of conducting the positive electrode current collector (the first current collector 11) and the negative electrode active material due to piercing the separator 30 by a large amount of particles such as burrs and beads generated in the die cutting process of the first tab 50 can be reduced, thereby further reducing the risk of short-circuiting between the positive electrode and the negative electrode inside the battery cell 100.

Based on the above description, it should be understood that one first current collector 11, one first active material layer 12, one separator 30, one second active material layer 22, and one first current collector 11 are sequentially stacked before the battery cell 100 is not wound. And the width W1 of the first active material layer 12, the width W2 of the second active material layer 22, and the width W3 of the separator 30 satisfy the relation: w1 is less than W2 and less than W3. It is understood that there is a risk of positional displacement in the X direction when the positive electrode sheet 10, the negative electrode sheet 20, and the separator 30 are wound, due to production accuracy such as the dimensional accuracy of the sheet, the winding accuracy, and the like. If the end of the negative electrode plate 20 in the X direction exceeds the end of the positive electrode plate 10, a lithium precipitation phenomenon occurs in the charging and discharging process of the energy storage device 200; if the separator 30 is displaced in the X-direction end, the positive electrode tab 10 and the negative electrode tab 20 are likely to be in direct contact with each other, and a short circuit is likely to occur. Therefore, in the embodiment of the present application, the width of the first active material layer 12 is smaller than the width W2 of the second active material layer 22, and the width W2 of the second active material layer 22 is smaller than the width W3 of the separator 30, so that the film widths of the positive electrode sheet 10 and the negative electrode sheet 20 are relatively close, and the manufacturing cost can be reduced by mutually matching the film widths of the positive electrode sheet 10 and the negative electrode sheet 20 while avoiding the problem of lithium precipitation and ensuring the safe operation of the battery cell 100.

In one possible embodiment, the width W1 of the first active material layer 12, the width W2 of the second active material layer 22, the width W3 of the separator 30, and the width L1 of the tab void region 114 satisfy the relationship: w2 < W1+L1X2 < W3. With this arrangement, the facing area between the first tab region 115 and the second active material layer 22 can be reduced, and the occurrence of internal short-circuiting between the positive electrode current collector and the negative electrode active material can be effectively avoided.

Referring to fig. 7 and 9 in combination, in the embodiment of the present application, the first tab 50 is disposed in the first tab area 115, and the second tab 60 is disposed in the second tab area 214. Specifically, the cell 100 may further include a first end 101 and a second end 102. As shown in fig. 7 and 9, both the first tab region 115 and the second tab region 214 may be located at the first end 101. Alternatively, both the first tab region 115 and the second tab region 214 may be located at the second end 102. Alternatively, the first tab region 115 is located at one of the first end 101 and the second end 102 and the second tab region 214 is located at the other of the first end 101 and the second end 102.

That is, in the Z direction, the first tab 50 and the second tab 60 may be located on the same side of the bare cell 40, or the first tab 50 and the second tab 60 may be located on different sides of the bare cell 40. When the first tab 50 and the second tab 60 are located on the same side of the bare cell 40, the single side of the bare cell 40 is provided with the tab, the first tab 50 on one side is electrically connected with the first pole piece, and the second tab 60 on the same side is connected with the negative pole piece 20, so that the preparation of the pole piece is realized. When the first tab 50 and the second tab 60 are located on different sides of the bare cell 40, the tabs are formed on two sides of the bare cell 40, one side of the bare cell 40 is connected with the first tab 50, the other side of the bare cell 40 is connected with the second tab 60, and when the battery is prepared, the contact between the positive tab and the negative tab is avoided, so that the battery is prepared.

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 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.

In the description of the embodiments of the present application, the technical terms "first," "second," etc. are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" means two or more than two, unless specifically defined otherwise.

Reference herein 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 present 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. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, which means that three relationships may exist, for example, a and/or B may mean: there are three cases, a, B, a and B simultaneously. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of describing the embodiments of the present application and for simplifying the description, rather than indicating or implying that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to the specific circumstances.

Finally, it should be noted that the above embodiments are merely for illustrating the technical solution of the present application and not for limiting, and although the present application has been described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or equivalent replaced without departing from the spirit and scope of the technical solution of the present application.

Claims

1. The bare cell is characterized by comprising a positive electrode plate, a diaphragm and a negative electrode plate, wherein the diaphragm is clamped between the positive electrode plate and the negative electrode plate;

2. The bare cell according to claim 1, wherein the first current collector further comprises a tab void region connected between the first coating region and the first tab region, the tab void region being spaced apart from the first active material layer in a direction of the first coating region toward the first tab region.

3. The bare cell according to claim 2, wherein at least a portion of the tab void region is disposed opposite the second active material layer in a direction in which the first coating region faces the first tab region.

4. The bare cell of claim 2 wherein the ratio of the width of the tab void to the width of the first current collector is between 0.02 and 0.04.

5. The bare cell of claim 2 wherein the first tab region has a thickness between 8um and 18 um.

6. The bare cell according to any one of claims 1 to 5, wherein a width W1 of the first active material layer, a width W2 of the second active material layer, and a width W3 of the separator satisfy a relationship: w1 is less than W2 and less than W3.

7. The bare cell according to any one of claims 2 to 5, wherein a width W1 of the first active material layer, a width W2 of the second active material layer, a width W3 of the separator, and a width L1 of the tab void region satisfy the relationship: w2 < W1+L1X2 < W3.

8. The bare cell according to any one of claims 1-5 wherein the length of the negative electrode tab is greater than the length of the positive electrode tab.

9. An energy storage device comprising an end cap assembly and the bare cell of any of claims 1-8, the bare cell being electrically connected to the end cap assembly.

10. A powered device comprising the energy storage device of claim 9, the energy storage device configured to provide power to the powered device.