Battery cell, battery and electric device

Abstract

The invention relates to a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell, an electrode assembly, electrolyte and a liquid absorption assembly. The electrode assembly and the electrolyte are contained in the shell, and the liquid absorption assembly is arranged on at least part of the surface of the electrode assembly. The liquid absorption assembly comprises a base body layer and a liquid absorption layer. The liquid absorption layer is connected to at least one side surface of the substrate layer along the thickness direction of the substrate layer and is used for absorbing electrolyte, and the impact strength of the substrate layer is greater than that of the liquid absorption layer. And the liquid absorption assembly can absorb the electrolyte and utilize the free electrolyte in the battery, so that the utilization rate of the free electrolyte can be maximized, and no liquid leakage of the battery can be realized. The electrolyte can be discharged after the liquid absorption layer is extruded, and the electrolyte can be released to be utilized by the electrode assembly when needing to be utilized, so that the problem of free electrolyte corrosion is solved. The expansion of the liquid absorption layer improves the constraint on the electrode assembly, improves the supporting effect on the electrode assembly, and can improve the lithium precipitation problem of the thinned area.

Description

Battery cell, battery, and electric device TECHNICAL FIELD

[0001] The present application relates to a battery cell, a battery, and an electric device. BACKGROUND

[0002] In recent years, with the development of lithium ion battery technology, lithium ion batteries are widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power stations, and in many fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. Since lithium ion batteries have made great progress, higher requirements have been placed on their corrosion resistance, lithium precipitation suppression, etc.

[0003] SUMMARY

[0004] The purpose of the present application is to provide a battery cell, a battery, and an electric device.

[0005] Embodiments of the present application are implemented as follows:

[0006] In a first aspect, embodiments of the present application provide a battery cell, comprising:

[0007] a housing;

[0008] an electrode assembly accommodated in the housing;

[0009] an electrolyte accommodated in the housing;

[0010] a liquid absorbing assembly, the liquid absorbing assembly being arranged on at least part of a surface of the electrode assembly, the liquid absorbing assembly comprising a base layer and a liquid absorbing layer, the liquid absorbing layer being connected to at least one side surface of the base layer along a thickness direction of the base layer and being used to absorb the electrolyte, and the impact strength of the base layer being greater than that of the liquid absorbing layer.

[0011] In the above technical solution, the liquid absorbing assembly is arranged on the electrode assembly, and the liquid absorbing layer of the liquid absorbing assembly can absorb the electrolyte and expand, and can discharge the electrolyte after being extruded. The liquid absorbing assembly described above can absorb the electrolyte, utilize the free electrolyte in the battery, maximize the utilization rate of the free electrolyte, and realize "battery without leakage". The liquid absorbing layer can discharge the electrolyte after being extruded, and can release the electrolyte to the electrode assembly when the electrolyte is needed, thereby avoiding the problem of excessive free electrolyte corroding the electrode assembly, the top cover, and the bottom of the cell. When the liquid absorbing layer expands, it greatly improves the binding of the electrode assembly and improves the support of the electrode assembly, which can improve the lithium precipitation problem in the thinned area of the electrode assembly.

[0012] In some alternative embodiments, the electrode assembly comprises a main body region and a thinned region in the first direction, the thinned region being connected to the main body region, the thickness of the electrode tab of the electrode assembly in the main body region being greater than the thickness of the electrode tab of the electrode assembly in the thinned region.

[0013] The liquid absorption assembly is at least partially arranged in the thinned region.

[0014] In the above technical solution, by arranging the liquid absorption assembly at least partially in the thinned region, the binding effect on the electrode assembly can be greatly improved, the support effect on the thinned region of the electrode assembly can be improved, the tightness of the electrode tab and the diaphragm in the thinned region can be improved, and the lithium precipitation problem of the thinned region of the electrode assembly can be improved.

[0015] In some alternative embodiments,

[0016] The liquid absorption assembly is arranged in the main body region and the thinned region.

[0017] In the above technical solution, by arranging the liquid absorption layer with different thicknesses in the main body region and the thinned region, i.e., the thickness of the first liquid absorption layer is greater than the thickness of the second liquid absorption layer, the utilization of the liquid absorption assembly can be improved on the premise of improving the binding effect on the electrode assembly and the support effect on the thinned region.

[0018] In some alternative embodiments, the liquid absorption assembly comprises a first liquid absorption assembly and a second liquid absorption assembly, the first liquid absorption assembly is arranged in the thinned region; the first liquid absorption assembly comprises a first liquid absorption layer;

[0019] The second liquid absorption assembly is arranged in the main body region; the second liquid absorption assembly comprises a second liquid absorption layer;

[0020] The thickness of the first liquid absorption layer is greater than the thickness of the second liquid absorption layer.

[0021] In the above technical solution, by arranging the liquid absorption layer with different thicknesses in the main body region and the thinned region, i.e., the thickness of the first liquid absorption layer is greater than the thickness of the second liquid absorption layer, the utilization of the liquid absorption assembly can be improved on the premise of improving the binding effect on the electrode assembly and the support effect on the thinned region.

[0022] In some alternative embodiments, the thinned region is located at the edge of the electrode assembly.

[0023] In some alternative embodiments, the electrode assembly comprises an end face;

[0024] The liquid absorption assembly is arranged on the end face.

[0025] In the above technical solution, by arranging the liquid absorption assembly on the bottom surface, the free electrolyte at the bottom of the battery can be absorbed, thereby reducing the corrosion problem of the electrolyte on the bottom wall of the battery.

[0026] In some alternative embodiments, the liquid absorption assembly is arranged between the electrode assembly and the shell; and the base layer contacts the shell; the liquid absorption layer contacts a surface of the electrode assembly; and the base layer is provided with a hole.

[0027] In the above technical solution, the hole design of the base layer allows the electrolyte absorbed by the liquid absorption layer to achieve directional movement or directional storage effect; in combination with the built-in liquid absorption layer, the electrolyte can be stored in the battery, i.e., the directional storage effect. Moreover, the design of the liquid absorption layer on the inner side allows the electrolyte absorbed by the liquid absorption layer to be released in time when stressed, instead of being released outwardly, which is easy to lose or not easy to be absorbed again.

[0028] In some alternative embodiments, the base layer is bonded to the shell.

[0029] In some alternative embodiments, the electrode assembly includes a side surface; and the liquid absorption assembly is arranged on the side surface.

[0030] In the above technical solution, by arranging the liquid absorption assembly on the side surface of the electrode assembly, the liquid absorption layer is designed to be located on the inner side, which is conducive to absorbing and releasing the electrolyte and improving the utilization rate of the electrolyte.

[0031] In some alternative embodiments, the thickness of the liquid absorption layer is 50-100 μm.

[0032] In the above technical solution, by arranging the thickness of the liquid absorption layer to be 50-100 μm, sufficient electrolyte can be absorbed, the binding effect after swelling can be improved, the problem of corrosion of the electrode assembly by free electrolyte can be improved, and the problem of lithium precipitation in the thinned area can be improved.

[0033] In some alternative embodiments, the thickness of the liquid absorption layer is 60-80 μm.

[0034] In some alternative embodiments, the liquid absorption layer is a polystyrene film layer.

[0035] In the above technical solution, by arranging the liquid absorption layer to be a polystyrene film layer, the swelling effect of the liquid absorption layer can be effectively improved, so that it has good compressibility and good ductility, and the electrolyte is not easily absorbed too much, which can well cooperate with the swelling and compression that occurs when the battery breathes, without affecting the normal consumption of the electrolyte amount of the battery.

[0036] In some alternative embodiments, the number of liquid absorption layers includes multiple liquid absorption layers.

[0037] The multiple liquid absorption layers are provided with a glue layer.

[0038] In the above technical solution, by arranging the number of liquid absorption layers to include multiple liquid absorption layers, and by arranging the multiple liquid absorption layers with a glue layer, the swelling effect can be further improved, thereby improving the binding effect on the electrode assembly.

[0039] In some alternative embodiments, the thickness of the adhesive layer is 5-15 μm.

[0040] In the above technical solution, by setting the thickness of the adhesive layer to be 5-15 μm, effective adhesive force can be provided, and the overall comprehensive performance of the entire liquid absorption assembly is improved.

[0041] In some alternative embodiments, the thickness of the base layer is 5-15 μm.

[0042] In the above technical solution, by setting the thickness of the base layer to be 5-15 μm, sufficient support strength can be provided for the liquid absorption layer 120.

[0043] In some alternative embodiments, the base layer is a polyethylene terephthalate film layer or a heat-conducting silica gel layer.

[0044] In some alternative embodiments, the battery cell is a square cell.

[0045] In the above technical solution, the battery cell is a square cell, and the liquid absorption assembly arranged on the electrode assembly can better bind the electrode assembly, increase the support for the electrode assembly, and improve the lithium precipitation problem of the thinned area of the electrode assembly.

[0046] In a second aspect, the embodiments of the present application provide a battery, which comprises the battery cell provided in any of the embodiments of the first aspect.

[0047] In a third aspect, the embodiments of the present application provide an electric device, which comprises the battery cell provided in any of the embodiments of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0049] FIG. 1 is a schematic diagram of an embodiment of a liquid absorption assembly of the present application;

[0050] FIG. 2 is a schematic diagram of another embodiment of a liquid absorption assembly of the present application;

[0051] FIG. 3 is a schematic diagram of an embodiment of an electrode assembly of the present application provided with a liquid absorption assembly;

[0052] FIG. 4 is a schematic diagram of another embodiment of an electrode assembly of the present application provided with a liquid absorption assembly;

[0053] FIG. 5 is a schematic view of another embodiment of the electrode assembly of the present application provided with a liquid absorbing assembly;

[0054] FIG. 6 is a schematic view of another embodiment of the electrode assembly of the present application provided with a liquid absorbing assembly;

[0055] FIG. 7 is a schematic view of another embodiment of the electrode assembly of the present application provided with a liquid absorbing assembly;

[0056] FIG. 8 is a schematic view of another embodiment of the electrode assembly of the present application provided with a liquid absorbing assembly;

[0057] FIG. 9 is a schematic view of a battery cell of a square case structure according to an embodiment of the present application;

[0058] FIG. 10 is an exploded view of the battery cell according to an embodiment of the present application shown in FIG. 9;

[0059] FIG. 11 is a schematic view of a battery module according to an embodiment of the present application;

[0060] FIG. 12 is a schematic view of a battery pack according to an embodiment of the present application;

[0061] FIG. 13 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 7;

[0062] FIG. 14 is a schematic view of an electric device using the battery as a power source according to an embodiment of the present application;

[0063] FIG. 15 is a schematic view of a thinning region according to an embodiment of the present application.

[0064] Reference Signs: 1 - battery pack; 2 - upper case; 3 - lower case; 4 - battery module; 5 - battery cell; 51 - case; 52 - electrode assembly; 521 - negative electrode tab; 522 - positive electrode tab; 523 - separator; 53 - cover plate; 10 - liquid absorbing assembly; 110 - base layer; 111 - hole; 120 - liquid absorbing layer; 131 - thinning region; 132 - main body region; 133 - end surface; 134 - side surface; 140 - adhesive layer. DETAILED DESCRIPTION

[0065] The embodiments of the present application will be described in detail by way of examples as follows, however, those skilled in the art will appreciate that the examples below are intended to be illustrative only and are not intended to limit the scope of the present application. Unless otherwise specified, the conditions in the examples were carried out according to the conventional conditions or the conditions recommended by the manufacturers. Unless otherwise specified, the reagents or instruments used were conventional products that can be commercially available.

[0066] The embodiments of the present application will be described in detail below with reference to the drawings. The following examples are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application; the use of the terms "including," "comprising," "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0068] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0069] In the description of the embodiments of the present application, the technical terms "inner", "outer", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0070] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0071] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0072] In the embodiments of the present application, the same reference signs represent the same parts, and for the sake of brevity, detailed description of the same parts is omitted in different embodiments. It should be understood that the height, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall height, length, width and other dimensions of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0073] The free electrolyte in the battery causes corrosion problems to the electrode assembly, the battery top cover, the battery bottom wall, etc.

[0074] In addition, the edge of the electrode assembly currently has a thinning area with a thickness and an area density lower than those of the main body area. This causes two problems: first, the area density of the thinning area is lower than that of the main body area, which may cause the position NP (the ratio of the negative electrode capacity to the positive electrode capacity) of the thinning area to be lower than the design value, thereby causing the risk of lithium precipitation at the edge; second, the thickness of the thinning area is lower than that of the main body area, which causes uneven adhesion of the electrode sheet, tight adhesion of the electrode sheet and the separator in the thinning area, and an increase in the gap between the positive and negative electrode sheets and the transmission distance of lithium ions, thereby causing the problem of lithium precipitation in the thinning area to be more serious.

[0075] Referring to FIGS. 1-9, based on this, the first aspect of the embodiments of the present application provides a battery monomer 5, comprising:

[0076] a shell 51;

[0077] an electrode assembly 52 accommodated in the shell 51;

[0078] an electrolyte accommodated in the shell;

[0079] a liquid absorption assembly 10, the liquid absorption assembly 10 is arranged on at least part of the surface of the electrode assembly 52; the liquid absorption assembly 10 comprises a base layer 110 and a liquid absorption layer 120; the liquid absorption layer 120 is connected to at least one side surface of the base layer 110 in the thickness direction of the base layer 110 and is used for absorbing the electrolyte; and the impact strength of the base layer 110 is greater than that of the liquid absorption layer 120.

[0080] In the above technical solution, the liquid absorption layer 120 can absorb the electrolyte and swell, and can discharge the electrolyte after being extruded.

[0081] In the above technical solution, by arranging the liquid absorption assembly 10 on the electrode assembly 52, and the liquid absorption layer 120 of the liquid absorption assembly 10 can absorb the electrolyte and swell, and can discharge the electrolyte after being extruded. The liquid absorption assembly 10 described above can absorb the electrolyte, utilize the free electrolyte in the battery, maximize the utilization rate of the free electrolyte, and realize "battery without leakage". The liquid absorption layer 120 can release the electrolyte when needed to utilize the electrolyte, thereby avoiding the problems of corrosion of the electrode assembly, the battery top cover, and the bottom caused by excessive free electrolyte. In addition, the liquid absorption layer 120 greatly improves the binding to the electrode assembly 52 when swelling, improves the supporting effect of the electrode assembly, and can improve the problem of lithium precipitation in the thinning area of the electrode assembly.

[0082] Further, the liquid absorption assembly 10 is arranged on the electrode assembly 52; the liquid absorption layer 120 of the liquid absorption assembly 10 can be expanded, and the expansion can enhance the binding of the electrode assembly 52, reduce the risk of wrinkling, and improve the interface. Moreover, the liquid absorption layer 120 can absorb the electrolyte and expand, and the liquid absorption layer 120 can discharge the electrolyte after being extruded, so that the liquid absorption assembly 10 has good compressibility, that is, the liquid absorption assembly 10 has good ductility, can avoid excessive absorption of the electrolyte, and can well cooperate with the expansion and compression of the battery assembly during breathing, without affecting the normal consumption of the electrolyte amount of the battery assembly.

[0083] In the technical solution, the base layer 110 mainly plays a mechanical support role, an electrolyte resistance role, and a certain waterproof and oxygen isolation role; the base layer 110 has a higher impact strength, can effectively reduce the warping of the liquid absorption layer 120, and has good stress cracking performance.

[0084] In some embodiments of the present application, the impact strength can be represented by the stress cracking performance.

[0085] Exemplarily, the method for measuring the stress cracking performance includes the following steps:

[0086] S1, preparing a sample: preparing a sample with a corresponding size and shape according to the type of the material or product to be tested;

[0087] S2, environmental control: placing the sample in a temperature control box and a humidity control box, and controlling the normal temperature and 50% humidity;

[0088] S3, loading stress: fixing the sample on an environmental stress cracking resistance testing machine, and applying a predetermined size of mechanical stress;

[0089] S4, periodic loading: periodically loading the sample according to a predetermined time interval and loading amplitude;

[0090] S5, observation and recording: after each time interval, observing the cracking of the sample using a microscope, and recording the number of cracks, the length of the cracks, and other information;

[0091] S6, data processing and analysis: analyzing the environmental stress cracking resistance performance of the sample according to the observed and recorded data.

[0092] Exemplarily, in some optional embodiments of the present application, the base layer 110 can be selected from PET; the liquid absorption layer 120 can be selected from OPS; and the base layer 110 has a higher impact strength.

[0093] Further, in some embodiments of the present application, the "battery cell" mentioned above can be a lithium ion battery cell or the like. Generally, a battery cell includes an electrode assembly and an electrolyte; the "electrode assembly" includes a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator. During the charging and discharging of the battery, active ions are embedded and extracted between the positive electrode sheet and the negative electrode sheet. The electrolyte plays a role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet, and mainly plays a role of preventing the short circuit of the positive electrode and the negative electrode, while allowing the ions to pass through.

[0094] Referring to FIG. 15, in some embodiments of the present application, the electrode assembly mentioned above can be formed by stacking or winding the positive electrode sheet 522, the negative electrode sheet 521, and the separator 523 in this order. As a whole, the electrode assembly 52 can be arranged at different positions on the surface of the electrode assembly 52.

[0095] Referring to FIG. 3, in some embodiments of the present application, the electrode assembly 52 has a thinned area 131; along a first direction (such as the arrow direction in FIG. 15), the electrode assembly 52 includes a main body area 132 and the thinned area 131, the thinned area 131 is connected to the main body area 132, and the thickness of the electrode sheet of the electrode assembly 52 in the main body area 132 is greater than the thickness of the electrode sheet of the electrode assembly 52 in the thinned area 131.

[0096] The liquid-absorbing assembly 10 is arranged at least partially in the thinned area 131.

[0097] In the technical solution mentioned above, by arranging the liquid-absorbing assembly 10 at least partially in the thinned area 131, the electrode assembly 52 can be greatly restrained, the support of the thinned area 131 of the electrode assembly can be improved, the tightness of the electrode sheet and the separator in the thinned area 131 can be improved, and the lithium precipitation problem of the thinned area of the electrode assembly can be improved.

[0098] Further, referring to FIG. 15, in some embodiments of the present application, the "thinned area 131" mentioned above is a meaning known in the art, and generally can be understood as a region with a smaller thickness in the electrode assembly 52. The gap (GAP) of the thinned area 131 is relatively large compared with the main body area 132.

[0099] Referring to FIG. 4, further, in some embodiments of the present application,

[0100] The liquid-absorbing assembly 10 is arranged in the main body area 132 and the thinned area 131.

[0101] In the technical solution, the liquid absorption assembly 10 is arranged in the main body area 132 and the thinning area 131, which further helps to improve the restraint on the electrode assembly 52, improve the tightness of the thinning area 131 of the electrode assembly, and improve the support of the thinning area 131 of the electrode assembly, and improve the problem of lithium precipitation in the thinning area of the electrode assembly.

[0102] In the technical solution, the main body area 132 is a commonly known meaning in the art, which can be understood as a region in the electrode assembly 52 that has a larger thickness than the aforementioned thinning area 131 and is located in the middle.

[0103] Referring to FIG. 5, further, in some embodiments of the application, the liquid absorption assembly 10 includes a first liquid absorption assembly and a second liquid absorption assembly, the first liquid absorption assembly is arranged in the thinning area 131; the first liquid absorption assembly includes a first liquid absorption layer;

[0104] The second liquid absorption assembly is arranged in the main body area 132; the second liquid absorption assembly includes a second liquid absorption layer;

[0105] The thickness of the first liquid absorption layer is greater than the thickness of the second liquid absorption layer.

[0106] In the technical solution, the liquid absorption assembly 10 is arranged in the main body area 132 and the thinning area 131, which further helps to improve the restraint on the electrode assembly 52, improve the tightness of the thinning area 131 of the electrode assembly, and improve the support of the thinning area 131 of the electrode assembly, and improve the problem of lithium precipitation in the thinning area of the electrode assembly.

[0107] Further, in some embodiments of the application, the aforementioned thinning area is located at the edge of the electrode assembly.

[0108] Referring to FIG. 6, further, in some embodiments of the application, the electrode assembly 52 includes an end surface 133;

[0109] The liquid absorption assembly 10 is arranged on the end surface 133.

[0110] In the technical solution, the liquid absorption assembly 10 is arranged on the end surface 133, which helps to absorb the free electrolyte at the end of the battery, thereby reducing the corrosion of the electrolyte on the end surface of the battery.

[0111] Further optionally, in some embodiments of the application, the aforementioned liquid absorption assembly 10 can be directly bonded to the end surface 133 of the electrode assembly to absorb the free electrolyte at the end surface of the battery assembly.

[0112] Alternatively, in some optional embodiments of the application, an insulating film (such as Mylar) is arranged on the end surface 133 of the electrode assembly; then the liquid absorption assembly 10 is bonded to the insulating film, which also can absorb the free electrolyte at the end surface of the battery assembly.

[0113] In the technical solution, the end face is a meaning known in the art, and can be understood as a face of the pole piece stack, when the electrode assembly is a wound electrode assembly, the end face is two faces perpendicular to the winding axis, and when the electrode assembly is a stacked electrode assembly, the end face is four faces parallel to the stacking direction.

[0114] Referring to FIG. 7, further, in some embodiments of the application,

[0115] The liquid absorption assembly 10 is arranged between the electrode assembly 52 and the shell 51, the base layer 110 contacts the shell 51, the liquid absorption layer 120 contacts the surface of the electrode assembly 52, and the base layer 110 is provided with holes 111.

[0116] In the technical solution, the holes in the base layer 110 can achieve the effect of directional movement or directional storage of the electrolyte absorbed by the liquid absorption layer 120, for example, only the upper liquid absorption layer 120 can absorb more or only the upper liquid absorption layer 120 can absorb the electrolyte, by punching holes 111 in the upper base layer 110 (as shown in FIG. 7). In combination with the built-in liquid absorption layer 120, the holes in the base layer 110 can also achieve the effect of built-in electrolyte, i.e., directional storage.

[0117] Further, in the technical solution, the liquid absorption layer 120 is arranged on the inner side, so that when stressed, the electrolyte absorbed by the liquid absorption layer 120 can be released to the electrode assembly (separator) in time, instead of being released to the outside, which is easy to lose or not easy to absorb again.

[0118] Further optionally, in some embodiments of the application, the holes 111 can be punched in the upper and lower base layers 110 (as shown in FIG. 8), in which case, in combination with the inner side of the liquid absorption layer 120, when stressed, the electrolyte absorbed by the liquid absorption layer 120 can be released to the electrode assembly in time, thereby improving the utilization rate of the electrolyte.

[0119] Further optionally, in some embodiments of the application, the holes 111 are uniformly punched in the base layer 110 (when only the upper half of the base layer 110 is punched, the adjacent holes 111 are uniformly spaced), which is conducive to uniform release and absorption of the electrolyte.

[0120] Further optionally, in some embodiments of the application, the shape (cross section) of the holes 111 can be selected from a circular hole, a square hole or an irregular hole.

[0121] Further, in some embodiments of the application, the base layer is bonded to the shell.

[0122] Further, referring to FIGS. 1-10, in some embodiments of the present application, the electrode assembly 52 comprises a side surface 134; the liquid absorption assembly 10 is arranged on the side surface 134.

[0123] In the above technical solution, by arranging the liquid absorption assembly 10 on the side surface 134 of the electrode assembly 52, it is beneficial to design the liquid absorption layer 120 to be located on the inner side, and it is beneficial to absorb the released electrolyte and improve the utilization rate of the electrolyte.

[0124] In the above technical solution, the "side surface" is a meaning known in the art, which can be generally understood as a surface connected to a large surface in the electrode assembly 52, and the side surface generally has multiple side surfaces.

[0125] Further, in some embodiments of the present application, referring to FIGS. 1-2, the thickness of the liquid absorption layer 120 is 50 μm-100 μm.

[0126] In the above technical solution, by arranging the thickness of the liquid absorption layer 120 to be 50 μm-100 μm, it is beneficial to absorb sufficient electrolyte, beneficial to improve the binding effect after swelling, beneficial to improve the problem of corrosion of the electrode assembly by free electrolyte, and beneficial to improve the problem of lithium precipitation in the thinned area.

[0127] Illustratively, in some embodiments of the present application, the thickness of the liquid absorption layer 120 described above is 50 μm, 55 μm, 58 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, or a thickness within a range between any two of the foregoing values.

[0128] Further optionally, in some embodiments of the present application, the thickness of the liquid absorption layer 120 is 60 μm-80 μm.

[0129] It should be noted that the thickness of the liquid absorption layer 120 described above is the cumulative thickness of the liquid absorption layer 120. For example, when the liquid absorption layer 120 comprises multiple liquid absorption layers 120, the cumulative thickness of the multiple liquid absorption layers 120 is within the range of 50 μm-100 μm.

[0130] Further, in some embodiments of the present application, the liquid absorption layer 120 is a polystyrene film layer.

[0131] In the above technical solution, by arranging the liquid absorption layer to be a polystyrene film layer, the swelling effect of the liquid absorption layer can be effectively improved, so that it has good compressibility and good ductility, and the electrolyte can be prevented from being absorbed too much, so that it can well cooperate with the swelling and compression that occurs during battery breathing, without affecting the normal consumption of the electrolyte amount by the battery.

[0132] Illustratively, in some embodiments of the present application, the liquid absorption layer 120 described above is made of OPS material.

[0133] Further, in some embodiments of the present application, referring to FIG. 2, the number of the liquid absorbing layers 120 comprises a plurality of;

[0134] The plurality of liquid absorbing layers 120 are provided with the adhesive layers 140.

[0135] In the above technical solution, by setting the number of the liquid absorbing layers 120 to comprise a plurality of, and the plurality of liquid absorbing layers 120 are provided with the adhesive layers 140, the swelling effect can be further improved, thereby improving the binding effect on the electrode assembly 52.

[0136] For example, in some embodiments of the present application, the number of the liquid absorbing layers 120 can be set to three; that is, the liquid absorbing assembly 10 comprises three liquid absorbing layers, and the adjacent liquid absorbing layers 120 can be bonded together by the adhesive layers 140.

[0137] In other optional embodiments of the present application, the number of the liquid absorbing layers 120 can also comprise other numbers, such as two, four, or five, etc.; which can be changed according to the needs of different batteries. For example, if the swelling demand is higher, the liquid absorbing layer 120 can be thickened or the number of the liquid absorbing layer 120 can be increased.

[0138] Further optionally, in some embodiments of the present application, the adhesive layer 140 mainly plays a role of providing adhesion, and the adhesive layer 140 will not be reacted by the electrolyte and has electrolyte resistance. For example, the adhesive layer 140 can be made of acrylate glue or the like.

[0139] Further, in some embodiments of the present application, the thickness of the adhesive layer 140 is 5-15 μm.

[0140] In the above technical solution, by setting the thickness of the adhesive layer 140 to be 5-15 μm, effective bonding force can be provided, and the overall comprehensive performance of the entire liquid absorbing assembly 10 can be improved.

[0141] It should be noted that the thickness of the adhesive layer 140 is the thickness of a single adhesive layer.

[0142] Further optionally, for example, in some embodiments of the present application, the thickness of the adhesive layer 140 is 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or a thickness within a range between any two of the foregoing values.

[0143] Further, in some embodiments of the present application, the thickness of the base layer 110 is 5-15 μm.

[0144] In the technical solution, the thickness of the base layer 110 is set to 5-15 μm, which can provide sufficient support strength for the liquid absorbing layer 120.

[0145] For example, in some embodiments of the present application, the thickness of the base layer 110 is 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm or a range between any two of the above values.

[0146] Further, in some embodiments of the present application, the base layer is a polyethylene terephthalate film layer or a heat-conducting silica gel layer.

[0147] For example, the material of the base layer 110 can be PET (polyethylene terephthalate) or other materials that can meet the requirement of resistance to electrolyte.

[0148] Further, in some other optional embodiments of the present application, the material of the base layer 110 can be a material that is resistant to electrolyte and meets the requirement of heat conduction. For example, the material of the base layer 110 can be heat-conducting silica gel.

[0149] Further, in some embodiments of the present application, the battery cell 5 is a square can battery cell.

[0150] In the technical solution, the battery cell 5 is a square can battery cell, and the liquid absorbing assembly 10 arranged on the electrode assembly 52 can better bind the electrode assembly and increase the support to the electrode assembly, thereby improving the lithium precipitation problem of the thinned area of the electrode assembly.

[0151] [Positive electrode tab]

[0152] The positive electrode tab includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector.

[0153] For example, the positive electrode current collector has two opposite surfaces in the thickness direction thereof, and the positive electrode film layer is arranged on any one or both of the two opposite surfaces of the positive electrode current collector.

[0154] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil can be used. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0155] In some embodiments, when the battery cell is a lithium ion battery, the positive electrode active material can employ a positive electrode active material for a lithium ion battery known in the art. As an example, the positive electrode active material can include at least one of a lithium-containing phosphate of an olivine structure, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material for a battery can also be used. These positive electrode active materials can be used alone only one or two or more can be used in combination. Among them, examples of the lithium transition metal oxide can include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(also referred to simply as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2(also referred to simply as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(also referred to simply as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also referred to simply as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also referred to simply as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2), and modified compounds thereof, etc. Examples of the lithium-containing phosphate of an olivine structure can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to simply as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite of lithium manganese iron phosphate and carbon.

[0156] In some embodiments, in order to further improve the energy density of the battery cell, the positive electrode active material for a lithium ion battery can include a compound represented by the general formula Li a Ni b Co c M d Oe A f one or more of lithium transition metal oxides and modified compounds thereof; wherein, 0.8 ≤ a ≤ 1.2, 0.5 ≤ b < 1, 0 < c < 1, 0 < d < 1, 1 ≤ e ≤ 2, 0 ≤ f ≤ 1, M is selected from one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A is selected from one or more of N, F, S, and Cl.

[0157] In some embodiments, by way of example, the positive electrode active material for a lithium ion battery may include LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (NCM 523 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM 811 )、LiNi 0.85 Co 0.15 Al 0.05 O2, LiFePO4, and LiMnPO4, or one or more of them.

[0158] In this application, the modified compounds of the above positive electrode active materials may be doping modification and / or surface coating modification of the positive electrode active materials.

[0159] In some embodiments, the above positive electrode active materials may be polyanion-type compounds.

[0160] As an optional technical solution of this application, the polyanion-type compound may be Li 1+x Mn 1-y A y P 1-z R z O4; wherein, x is any value within the range of -0.100 to 0.100, y is any value within the range of 0.001 to 0.500, z is any value within the range of 0.001 to 0.100, A includes one or more elements selected from Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and R includes one or more elements selected from B, S, Si, and N;

[0161] As an optional technical means of the present application, the polyanionic compound can be Li a A e Mn 1-f B f P 1-g C g O 4-n D n , wherein A comprises one or more elements of Zn, Al, Na, K, Mg, Nb, Mo, and W; B comprises one or more elements of Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; C comprises one or more elements of B, S, Si, and N; D comprises one or more elements of S, F, Cl, and Br; a is selected from the range of 0.9 to 1.1, e is selected from the range of 0.001 to 0.1, f is selected from the range of 0.001 to 0.5, g is selected from the range of 0.001 to 0.1, n is selected from the range of 0.001 to 0.1, and the second positive electrode active material is electrically neutral.

[0162] The battery will be accompanied by Li de-intercalation and consumption during charging and discharging, and the molar content of Li is different when the battery is discharged to different states. In the enumeration of the positive electrode material in the present application, the molar content of Li is the initial state of the material, i.e. the state before feeding, and the positive electrode material is applied to the battery system. After charging and discharging cycle, the molar content of Li will change.

[0163] In the enumeration of the positive electrode material in the present application, the molar content of O is only the theoretical state value, and the release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual molar content of O will appear to float.

[0164] In some embodiments, the positive electrode film layer also optionally includes a binder. As an example, the binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylic ester resin.

[0165] In some embodiments, the positive electrode film layer also optionally includes a conductive agent. As an example, the conductive agent can include at least one of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0166] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on a positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0167] [negative electrode sheet]

[0168] In some embodiments of the present application, the specific type of negative electrode active material in the film layer is not limited, and active materials known in the art that can be used in the negative electrode of a sodium-ion battery can be used, and a person skilled in the art can select according to actual needs. As an example, the negative electrode active material can include but is not limited to carbon materials, including but not limited to at least one of hard carbon, soft carbon, amorphous carbon, nanostructured carbon material, etc., which can be obtained by commercial means.

[0169] For example, the negative electrode active material can include one or more of hard carbon, soft carbon, artificial graphite, and natural graphite.

[0170] In some embodiments, the current collector of the negative electrode sheet can further include a current collector body and a primer layer, which can be provided on at least one side of the current collector body. The primer layer is substantially free of negative electrode active material and can include a small amount of carbon material, but the carbon material forms a coating with a thickness that is too thin to function as a negative electrode active material. In this embodiment, the negative electrode sheet can be a negative electrode sheet without a negative electrode active material layer. For a negative electrode sheet without a negative electrode active material layer, when the current collector of the negative electrode sheet does not include a primer layer, the film layer can be provided on the surface of at least one side of the current collector; when the current collector of the negative electrode sheet includes a primer layer, the film layer can be provided on the surface of the side of the primer layer away from the current collector.

[0171] In some embodiments, the film layer can further include a binder for fixing the additive to the negative electrode sheet. The type of the binder is not particularly limited, and a person skilled in the art can select it flexibly according to actual needs.

[0172] [electrolyte]

[0173] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium difluoroboric bisoxalate, lithium difluorophosphoric bisoxalate, and lithium tetrafluorophosphoric oxalate.

[0174] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0175] In some embodiments, the electrolyte solution can further optionally include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and can further include an additive capable of improving certain properties of the battery, such as an additive for improving overcharge performance of the battery, an additive for improving high-temperature or low-temperature performance of the battery, etc.

[0176] [Separator]

[0177] In some embodiments, the type of the separator is not particularly limited, and any known porous structure separator having good chemical stability and mechanical stability can be used.

[0178] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multi-layer composite film, the materials of the respective layers can be the same or different, and are not particularly limited.

[0179] In some embodiments, the battery cell can include an outer package. The outer package can be used to encapsulate the electrode assembly and the electrolyte solution described above.

[0180] In some embodiments, the outer package of the battery cell can be a hard shell such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package of the battery cell can also be a soft package such as a pouch-type soft package. The material of the soft package can be plastic, and as the plastic, polypropylene, polybutylene terephthalate, polybutylene succinate, etc. can be exemplified.

[0181] The shape of the battery cell of the present application can be cylindrical, cuboid, or any other shape. For example, FIG. 9 is a battery cell 5 of a cuboid structure as an example.

[0182] In some embodiments, referring to FIG. 10, the outer package includes a housing 51 and a cover plate 53. The housing 51 can include a bottom plate and side plates connected to the bottom plate, which enclose a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be arranged on the opening to close the receiving cavity. The positive electrode tab, the negative electrode tab, and the separator film can be wound or stacked to form an electrode assembly 52. The electrode assembly 52 is packaged in the receiving cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, which can be selected by a person skilled in the art according to specific actual needs.

[0183] Some embodiments of the present application provide a battery, which includes the battery cell provided in any of the preceding embodiments.

[0184] In the above technical solutions, the term "battery" can be a battery module or a battery pack.

[0185] For example, in some embodiments, the battery cell can be assembled into a battery module, and the number of battery cells contained in the battery module can be one or more, and the specific number can be selected by a person skilled in the art according to the application and capacity of the battery module.

[0186] FIG. 11 is a battery module 4 as an example. Referring to FIG. 11, in the battery module 4, a plurality of battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, other arbitrary arrangements can also be used. Further, the plurality of battery cells 5 can be fixed by fasteners.

[0187] Optionally, the battery module 4 can further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0188] In some embodiments, the above battery module can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by a person skilled in the art according to the application and capacity of the battery pack.

[0189] FIGS. 12 and 13 are a battery pack 1 as an example. Referring to FIGS. 12 and 13, the battery pack 1 can include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be arranged on the lower box body 3 to form a closed space for receiving the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0190] The second aspect of the embodiments of the present application provides a power consumption device.

[0191] The electric device includes at least one of the battery cell, the battery module, or the battery pack provided by the present application. The battery cell, the battery module, or the battery pack can be used as a power supply of the electric device, and can also be used as an energy storage unit of the electric device. The electric device can include a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc., but is not limited thereto.

[0192] As the electric device, the battery cell, the battery module, or the battery pack can be selected according to the use requirement thereof.

[0193] FIG. 14 is an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirement of high power and high energy density of the electric device, the battery pack or the battery module can be used.

[0194] As another example of the device, it can be a mobile phone, a tablet computer, a notebook computer, etc. The device usually requires thin and light, and the battery can be used as a power supply.

[0195] The above-described embodiments are part of the embodiments of the present application, rather than all the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

Claims

1. A battery cell, characterized by, The battery cell comprises: a housing; an electrode assembly accommodated in the housing; an electrolyte accommodated in the housing; a liquid-absorbing assembly arranged on at least a part of a surface of the electrode assembly, the liquid-absorbing assembly comprising a base layer and a liquid-absorbing layer connected to at least one side surface of the base layer in a thickness direction of the base layer and used for absorbing the electrolyte, and the impact strength of the base layer being greater than that of the liquid-absorbing layer.

2. The battery cell according to claim 1, wherein the electrode assembly comprises a main body region and a thinned region connected to the main body region in a first direction, and the thickness of the electrode assembly in the main body region is greater than that of the electrode assembly in the thinned region; the liquid-absorbing assembly is arranged at least partially in the thinned region.

3. The battery cell according to claim 2, wherein the liquid-absorbing assembly is arranged in the main body region and the thinned region.

4. The battery cell according to claim 3, wherein the liquid-absorbing assembly comprises a first liquid-absorbing assembly and a second liquid-absorbing assembly, the first liquid-absorbing assembly is arranged in the thinned region, and the first liquid-absorbing assembly comprises a first liquid-absorbing layer; the second liquid-absorbing assembly is arranged in the main body region, and the second liquid-absorbing assembly comprises a second liquid-absorbing layer; the thickness of the first liquid-absorbing layer is greater than that of the second liquid-absorbing layer.

5. The battery cell according to claim 2, wherein the thinned region is located at an edge of the electrode assembly.

6. The battery cell according to claim 1, wherein the electrode assembly comprises an end surface; the liquid-absorbing assembly is arranged on the end surface.

7. The battery cell according to any one of claims 1-6, wherein the liquid-absorbing assembly is arranged between the electrode assembly and the housing, the base layer contacts the housing, the liquid-absorbing layer contacts a surface of the electrode assembly, and the base layer is provided with a hole.

8. The battery cell according to claim 7, wherein the base layer is bonded to the housing.

9. The battery cell according to claim 7, wherein the electrode assembly comprises a side surface, and the liquid-absorbing assembly is arranged on the side surface.

10. The battery cell according to any one of claims 1-9, wherein the thickness of the liquid-absorbing layer is 50-100 μm.

11. The battery cell according to any one of claims 1-10, wherein the thickness of the liquid-absorbing layer is 60-80 μm.

12. The battery cell according to any one of claims 1-11, wherein the liquid-absorbing layer is a polystyrene film layer.

13. The battery cell according to any one of claims 1-12, wherein the number of the liquid-absorbing layers comprises a plurality of liquid-absorbing layers; a glue layer is arranged between the plurality of liquid-absorbing layers.

14. The battery cell according to claim 13, wherein the thickness of the glue layer is 5-15 μm.

15. The battery cell according to any one of claims 1-14, wherein the thickness of the base layer is 5-15 μm.

16. The battery cell according to any one of claims 1-15, wherein, the base layer is a polyethylene terephthalate film layer or a thermal conductive silica gel layer.

17. The battery cell according to any one of claims 1-16, wherein, the battery cell is a prismatic battery cell.

18. A battery, characterized by A battery pack comprising the battery cell according to any one of claims 1-17.

19. An electrical device, comprising: A battery pack comprising the battery cell according to any one of claims 1-17, wherein the battery pack is configured to provide electrical energy.

Images