Battery monomer and manufacturing method thereof, battery and electric device

Abstract

The invention provides a battery monomer and a manufacturing method thereof, a battery and a power utilization device. The battery monomer comprises an electrode plate and an adapter part, the electrode pole piece comprises a current collector and a tab component, the tab component comprises a plurality of tabs and a plurality of connecting pieces, the tabs are stacked in the first direction and connected with the current collector, the tabs are provided with through holes in the first direction, the connecting pieces are arranged on one sides of the tabs, and the tensile strength of the connecting pieces is smaller than that of the current collector. And the switching part is connected with the plurality of connecting pieces through the through holes. And the tensile strength of the connecting pieces is smaller than that of the current collector, so that the switching component is connected with the connecting pieces through the through holes of the tab, the reliability of connection between the switching component and the connecting pieces can be improved, the probability of cracking of the tab component can be reduced, and the manufacturing yield of the battery is improved.

Description

battery cells 及 Its manufacturing method 、 Batteries and electrical equipment 置 Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a battery cell and a manufacturing method thereof, a battery, and an electrical device. Background Art

[0002] Batteries have become an indispensable energy supply device in consumer electronics, electric transportation, power tools, energy storage, and other fields, and the demand for them in these fields is increasing. Therefore, it is urgent to improve the manufacturing yield of batteries to meet the needs of various fields.

[0003] Summary of the Invention

[0004] The present application provides a battery cell and a manufacturing method thereof, a battery and an electrical device, which can improve the manufacturing yield of the battery.

[0005] In a first aspect, the present application provides a battery cell comprising an electrode sheet and a transition component. The electrode sheet comprises a current collector and a tab component, which comprises a plurality of tabs and a plurality of connectors. The plurality of tabs are stacked along a first direction and connected to the current collector. The tabs have through-holes extending along the first direction. The connectors are provided on at least one side of the tabs, and the tensile strength of the connectors is less than that of the current collector. The transition component is connected to the plurality of connectors via the through-holes.

[0006] In the electrode assembly provided in the present application, the pole ear component includes multiple pole ears and multiple connectors. The connector is arranged on at least one side of the pole ear, and the tensile strength of the connector is less than the tensile strength of the current collector. Therefore, the adapter component is connected to the multiple connectors through the through holes of the pole ear, which can improve the reliability of the connection between the adapter component and the connector and reduce the probability of cracking of the pole ear component, thereby improving the manufacturing yield of the battery.

[0007] According to any of the aforementioned embodiments of the first aspect of the present application, the tensile strength of the current collector is 450 MPa-1500 MPa, and optionally 500 MPa-800 MPa. When the tensile strength of the current collector is set within the above range, the compaction density of the active material layer in the electrode sheet can be increased, thereby improving the volumetric energy density of the battery.

[0008] According to any of the aforementioned embodiments of the first aspect of the present application, the elongation at break of the current collector is less than or equal to 2%, and can be optionally 0.4%-1.9%. When the elongation at break of the current collector is set within the above range, wrinkling of the electrode sheet can be reduced, thereby reducing the probability of active material in the electrode sheet falling off.

[0009] According to any of the aforementioned embodiments of the first aspect of the present application, the resistivity R1 of the current collector is 1×10 -3 Ω / m-4.5×10 -3 When the resistance of the current collector is set within the above range, the battery can have an appropriate resistance, which helps to improve its cycle performance.

[0010] According to any of the aforementioned embodiments of the first aspect of the present application, the thickness d1 of the current collector is 5 μm-20 μm. Setting the thickness of the current collector within the above range can provide the current collector with suitable mechanical strength while increasing the space for filling active materials, thereby improving the energy density of the battery.

[0011] According to any of the aforementioned embodiments of the first aspect of the present application, the tensile strength of the connector is 150 MPa-400 MPa. When the tensile strength of the connector is set within the above range, the adapter component is connected to the tab through the through hole, which not only helps reduce the probability of cracking of the connector, thereby reducing the crack rate of the tab component, but also enhances the reliability of the connection between the tab and the adapter component, thereby further improving the manufacturing yield of the battery.

[0012] According to any of the aforementioned embodiments of the first aspect of the present application, the elongation at break of the connector is 3%-10%. When the elongation at break of the connector is set within the above range, the probability of cracking can be further reduced, which helps to reduce the cracking rate of the tab component, thereby facilitating an improvement in the manufacturing yield of the battery.

[0013] According to any of the aforementioned embodiments of the first aspect of the present application, the material of the connector includes one or more of aluminum, nickel, and copper. The inclusion of any one or more of the aforementioned materials in the connector can help reduce the probability of cracking and improve the reliability of its connection to the adapter component.

[0014] According to any of the aforementioned embodiments of the first aspect of the present application, the resistivity R2 of the connector is 0.1×10 -3 Ω / m-2×10 -3 When the resistance of the connector is set within the above range, the transmission characteristics of electrons in the connector can be improved, so that the battery has better dynamic performance.

[0015] According to any of the aforementioned embodiments of the first aspect of the present application, the thickness d2 of the connector is 5 μm-20 μm. When the thickness of the connector is set within the above range, it can help it have appropriate mechanical strength, reduce the probability of cracking, and improve the mass energy density of the battery.

[0016] According to any of the foregoing embodiments of the first aspect of the present application, the electrode tab further includes an active material layer disposed on at least one side of the current collector. In the width direction of the current collector, the distance between the connecting member and the active material layer is 3 mm - 10 mm. By setting the distance between the connecting member and the active material layer within the above range, the damage to the active layer caused by the connecting member or the connection between the connecting member and the转接部件 (transfer component) can be reduced.

[0017] According to any of the foregoing embodiments of the first aspect of the present application, the distance between the connecting member and the end of the tab away from the active material layer is less than or equal to 5 mm. When the distance between the connecting member and the end of the tab away from the active material layer is set within the above range, it can help reduce the overcurrent resistance of the connecting member while also improving the energy density of the battery.

[0018] According to any of the foregoing embodiments of the first aspect of the present application, the transfer component includes one or more of aluminum, nickel, and copper. This helps with the electrical connection between the connecting member and the transfer component, further improving the reliability of the connection between the transfer component and the connecting member.

[0019] According to any of the foregoing embodiments of the first aspect of the present application, the area S1 of the connecting member, the area S2 of the tab, the area S3 of the through-hole, and the contact area S4 between the transfer component and the connecting member satisfy: S4 < S3 < S1 < S2. When S1, S2, S3, and S4 satisfy the above relationship, it can help improve the connection reliability between the transfer component and the connecting member.

[0020] According to any of the foregoing embodiments of the first aspect of the present application, the area difference S5 between the area of the overlapping part of the connecting member and the tab and the area S3 of the through-hole, and the contact area S4 between the connecting member, the tab, and the transfer component and the connecting member satisfy: S4 * d1 * R1 / (d2 * R2 + d1 * R1) < S5 < S1, where d1 represents the thickness of the connecting member in μm; R1 represents the resistivity of the connecting member in mΩ; d2 represents the thickness of the tab in μm; R2 represents the resistivity of the tab in mΩ. When S1, S, and S5 satisfy the above relationship, it can help improve the overcurrent capacity of the tab component.

[0021] In a second aspect, the present application provides a manufacturing method of a battery cell as in the first aspect of the present application, including:

[0022] Providing a current collector;

[0023] Intermittently opening a plurality of through-holes in the edge area of the current collector, and disposing a connecting member on at least one side of the edge area, and then forming a plurality of tabs and a plurality of connecting members through cutting treatment to obtain an electrode tab, wherein the tensile strength of the connecting member is less than or equal to the tensile strength of the current collector;

[0024] Performing winding or stacking treatment on the electrode tab to form a tab component;

[0025] The adapter component is connected to a plurality of connectors through the through hole and assembled to obtain a battery cell.

[0026] In the manufacturing method of the battery cell provided in the present application, the above-mentioned manufacturing method can reduce the difficulty of connecting the tabs, and can also reduce the occurrence of cracks caused by the connection of the tabs, thereby improving the manufacturing yield and production output of the battery.

[0027] According to any of the aforementioned embodiments of the second aspect of the present application, the connector is connected to at least one side of the tab by roller welding. Roller welding of the connector to at least one side of the tab not only helps improve the connection reliability between the connector and the tab, but also helps improve the manufacturing efficiency of the battery.

[0028] According to any of the aforementioned embodiments of the second aspect of the present application, the adapter component is connected to multiple connectors by ultrasonic welding. The use of ultrasonic welding can facilitate the electrical connection of the adapter component with multiple connectors along the thickness direction, and can also reduce the probability of separation between the adapter component and the connector.

[0029] In a third aspect, the present application provides a battery, comprising a battery cell according to the first aspect of the present application or a battery cell manufactured by the manufacturing method according to the second aspect of the present application.

[0030] In a fourth aspect, the present application provides an electrical device comprising the battery according to the third aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of this application, the following briefly introduces the drawings required for use in the embodiments of this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive effort.

[0032] FIG1 is a schematic top view of an electrode assembly in a battery cell provided in some embodiments of the present application.

[0033] FIG2 is a schematic diagram of the electrode plate of some embodiments of the present application shown in FIG1 .

[0034] FIG3 is a schematic diagram of the structure of the electrode plate connection provided in some embodiments of the present application.

[0035] FIG. 4 is a schematic diagram of a battery cell according to some embodiments of the present application.

[0036] FIG. 5 is an exploded view of the battery cell shown in FIG. 4 according to some embodiments of the present application.

[0037] FIG6 is a schematic diagram of a battery module according to some embodiments of the present application.

[0038] FIG7 is a schematic diagram of a battery pack according to some embodiments of the present application.

[0039] FIG8 is an exploded view of the battery pack shown in FIG7 according to some embodiments of the present application.

[0040] FIG9 is a schematic diagram of an electrical device using a battery as a power source according to some embodiments of the present application.

[0041] Description of reference numerals:

[0042] 1-battery pack, 2-upper box, 3-lower box, 4-battery module, 5-battery cell, 51-shell, 52-electrode assembly, 521-electrode pole piece, 5211-current collector, 5212-ear component, 5212a-ear, 5212b-through hole, 5212c-connector, 5512d-ultrasonic welding area, 522-transition component, 53-cover plate. DETAILED DESCRIPTION

[0043] Below, the embodiments of the current collector and its preparation method, electrode pole piece, electrode assembly, battery and electrical device of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0044] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0045] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0046] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of this application.

[0047] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0048] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0049] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0050] In this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0051] In this application, the terms "plurality" and "multiple" refer to two or more.

[0052] Unless otherwise specified, the terms used in this application have the common meanings that are commonly understood by those skilled in the art.

[0053] Unless otherwise stated, the numerical values ​​of the parameters mentioned in this application can be measured using various test methods commonly used in the art, for example, they can be measured according to the test methods given in the embodiments of this application.

[0054] In this application, a battery refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0055] Battery cells may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-ion battery cells, or magnesium-ion battery cells, and the present application does not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, and the present application does not limit this. Battery cells are generally divided into three types: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the present application does not limit this.

[0056] A battery cell usually includes an electrode assembly, which is the component in the battery cell where the electrochemical reaction occurs. The electrode assembly is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials constitute the positive electrode tab and the negative electrode tab respectively. The positive electrode tab and the negative electrode tab can be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs connect the electrode terminals to form a current circuit.

[0057] In the related art, the parts of the positive electrode sheet and the negative electrode sheet that do not have active materials are usually connected by welding to form the positive electrode tab and the negative electrode tab respectively. However, during the welding process, the connection reliability between the parts of the positive electrode sheet and the negative electrode sheet that do not have active materials is low, and cracks may occur, resulting in a low manufacturing yield of the battery.

[0058] In view of this, embodiments of the present application provide a battery cell and a manufacturing method thereof, a battery, and an electrical device, which can improve the manufacturing yield of the battery.

[0059] battery cells

[0060] Referring to Figures 1-3, an embodiment of the present application provides a battery cell including an electrode plate 521 and a transition component 522. The electrode plate 521 includes a current collector 5211 and a tab component 5212. The tab component 5212 includes a plurality of tabs 5212a and a plurality of connectors 5212c. The plurality of tabs 5212a are stacked along a first direction X and connected to the current collector 5211. The tabs 5212a have through-holes 5212b extending along the first direction X. The connectors 5212c are disposed on at least one side of the tabs 5212a, and the tensile strength of the connectors 5212c is less than that of the current collector 5211. The transition component 522 is connected to the plurality of connectors 5212c via the through-holes 5212b.

[0061] In the battery cell provided in the present application, the pole tab component 5212 includes multiple pole tabs 5212a and multiple connectors 5212c, and the connector 5212c is arranged on at least one side of the pole tab 5212a, and the tensile strength of the connector 5212c is less than the tensile strength of the current collector 5211. Therefore, the adapter component 522 is electrically connected to the multiple connectors 5212c through the through hole 5212b of the pole tab 5212a to electrically connect the multiple pole tabs 5212a, which can improve the reliability of the connection between the adapter component 522 and the connector 5212c and reduce the probability of cracking of the pole tab component 5212, thereby improving the manufacturing yield of the battery.

[0062] In addition, when the adapter component 522 is electrically connected to the plurality of connectors 5212c via the through-hole 5212b of the tab 5212a, the height increase of the tab component 5212 is small, thereby enabling the battery to have a higher volume energy density.

[0063] In the above embodiments, when some physical properties of the current collector 5211 (such as tensile strength, elongation at break, resistivity, etc.) are within an appropriate range, it can help improve the electrochemical performance of the battery, such as energy density and cycle performance.

[0064] In some embodiments of the present application, the current collector 5211 may include one or more of stainless steel or nickel-iron alloy. These high-strength substrates can increase the compaction density of the active material layer in the electrode plate 521, thereby helping to increase the volume energy density of the battery.

[0065] In this application, compaction density refers to the sum of the total mass of all materials constituting the active material layer (including the active material and its auxiliary materials such as conductive agents and binders, etc.) per unit volume.

[0066] In some embodiments of the present application, the material of the tab 5212a is the same as that of the current collector 5211, so that the current collector 5211 can be directly processed to form the tab 5212a connected thereto, thereby improving the manufacturing efficiency of the battery.

[0067] In some embodiments of the present application, the tensile strength of the current collector 5211 is 450 MPa-1500 MPa, and optionally 500 MPa-800 MPa. When the tensile strength of the current collector 5211 is set within the above range, the compaction density of the active material layer in the electrode plate 521 can be increased, thereby improving the volume energy density of the battery.

[0068] In this application, the tensile strength of the current collector 5211 has a meaning well known in the art and can be tested using methods and instruments well known in the art. For example, a sample with a length of 100 mm and a width of 15 mm is taken, accurate to 0.05 mm, and the sample is symmetrically clamped in the upper and lower clamps of the measuring tool with a spacing of 50 mm between the upper and lower clamps. The measuring tool is started and maintained at (5±1) mm / min, and the load is loaded at a steady speed. The maximum load of the sample shear failure is recorded, and then the tensile strength σt of the sample is calculated according to the following formula: σt=P / (b×d)

[0069] Where P is the maximum load (N), b is the width of the sample (mm), and d is the thickness of the sample.

[0070] In some examples, the tensile strength of the current collector 5211 may be, but is not limited to, 450 MPa, 500 MPa, 550 MPa, 600 MPa, 650 MPa, 700 MPa, 750 MPa, 800 MPa, 850 MPa, 900 MPa, 950 MPa, 1000 MPa, 1050 MPa, 1100 MPa, 1150 MPa, 1200 MPa, 1250 MPa, 1300 MPa, 1350 MPa, 400 MPa, 1450 MPa, 1500 MPa, or a range consisting of any two of the above values. For example, the tensile strength of the current collector 5211 may range from, but is not limited to, 450 MPa to 1450 MPa, 550 MPa to 1350 MPa, 600 MPa to 1250 MPa, and 700 MPa to 1100 MPa.

[0071] In some embodiments of the present application, the elongation at break of the current collector 5211 is less than or equal to 2%, and can be optionally 0.4%-1.9%. When the elongation at break of the current collector 5211 is set within the above range, it can reduce the occurrence of wrinkles in the electrode plate 521, thereby reducing the probability of active material in the electrode plate 521 falling off, thereby improving the cycle performance of the battery.

[0072] In this application, the elongation at break of the current collector 5211 has a meaning well known in the art and can be measured using methods and instruments well known in the art. For example, a sample 100 mm long and 15 mm wide is measured to the nearest 0.05 mm. The sample is symmetrically clamped between the upper and lower clamps of a measuring tool, with a spacing of 50 mm between the upper and lower clamps. The measuring tool is operated and maintained at a steady speed of (5±1) mm / min. The gap between the upper and lower clamps (m) at the time of sample fracture is recorded. Elongation at break = (m - 50) / 50 * 100%.

[0073] In some examples, the elongation at break of the current collector 5211 may be, but is not limited to, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or a range consisting of any two of the foregoing values. For example, the elongation at break of the current collector 5211 may be, but is not limited to, 0.5%-1.8%, 0.7%-1.6%, or 0.9%-1.4%.

[0074] In some embodiments of the present application, the resistivity R1 of the current collector 5211 is 1×10 -3 Ω / m-4.5×10 -3 When the resistance of the current collector 5211 is set within the above range, the battery can have an appropriate resistance, which helps to improve its cycle performance.

[0075] In this application, the resistance of the current collector 5211 has a meaning well known in the art, and can be tested using methods and instruments well known in the art, such as using a four-probe resistance meter with a probe spacing of 1 mm, a sample size of 100 mm*100 mm, and a test position in the middle of the sample. The resistivity of the sample = instrument display value / sample thickness.

[0076] In some examples, the resistivity R1 of the current collector 5211 may be, but is not limited to, 1×10 -3 Ω / m, 1.1×10 - 3 Ω / m, 1.2×10 -3 Ω / m, 1.3×10 -3 Ω / m, 1.4×10 -3 Ω / m, 1.5×10 -3 Ω / m, 1.6×10 -3 Ω / m, 1.7×10 - 3 Ω / m, 1.8×10 -3 Ω / m, 1.9×10 -3 Ω / m, 2.0×10 -3 Ω / m, 2.1×10 -3 Ω / m, 2.2×10 -3 Ω / m, 2.3×10 - 3 Ω / m, 2.4×10 -3 Ω / m, 2.5×10 -3 Ω / m, 2.6×10 -3 Ω / m, 2.7×10 -3 Ω / m, 2.8×10 -3 Ω / m, 2.9×10 - 3 Ω / m, 3.0×10 -3 Ω / m, 3.1×10 -3 Ω / m, 3.2×10 -3 Ω / m, 3.3×10 -3 Ω / m, 3.4×10 -3 Ω / m, 3.5×10 - 3 Ω / m, 3.6×10 -3 Ω / m, 3.7×10 -3 Ω / m, 3.8×10 -3 Ω / m, 3.9×10 -3 Ω / m, 4.0×10 -3 Ω / m, 4.1×10 - 3 Ω / m, 4.2×10-3 Ω / m, 4.3×10 -3 Ω / m, 4.4×10 -3 Ω / m, 4.5×10 -3 Ω / m or a range consisting of any two of the above values. For example, the resistivity R1 of the current collector 5211 may be in the range of, but not limited to, 1.1×10 -3 Ω / m-4.3×10 -3 Ω / m, 1.5×10 -3 Ω / m-4.0×10 -3 Ω / m, 1.8×10 -3 Ω / m-3.6×10 -3 Ω / m, 2×10 -3 Ω / m-×10 - 3 Ω / m.

[0077] In addition, the thickness d1 of the current collector 5211 is within a suitable range, which can provide the current collector with suitable mechanical strength while also allowing the electrode assembly to have a larger space for filling active materials, thereby improving the energy density of the battery.

[0078] In some embodiments of the present application, the thickness d1 of the current collector 5211 is 5 μm-20 μm. Setting the thickness of the current collector 5211 within the above range can provide the current collector with suitable mechanical strength while increasing the space for filling active materials, thereby improving the energy density of the battery.

[0079] In this application, the thickness of the current collector 5211 has a meaning well known in the art and can be measured using methods and instruments well known in the art, for example, a micrometer (such as Mitutoyo 293-100, with an accuracy of 0.1 μm).

[0080] In an embodiment of the present application, the connecting member 5212c is arranged on at least one side of the pole tab 5212a. It can be understood that the pole tab 5212a has two oppositely arranged sides, and the connecting member 5212c can be arranged on any side of the pole tab 5212a, or can be arranged on both sides of the pole tab 5212a.

[0081] In addition, when some physical properties of the connector 5212c (such as tensile strength, elongation at break, resistivity, etc.) are within an appropriate range, it can help improve the reliability of the connection between the connector 5212c and the transition component 522, and reduce the probability of cracking of the tab component 5212, thereby improving the manufacturing yield of the battery.

[0082] In some embodiments of the present application, the tensile strength of the connector 5212c is 150 MPa-400 MPa. When the tensile strength of the connector 5212c is set within the above range, the adapter component 522 is connected to the tab 5212a via the through hole 5212b. This not only helps reduce the probability of cracking of the connector 5212c, thereby reducing the crack rate of the tab component 5212, but also enhances the reliability of the connection between the tab and the adapter component 522, thereby further improving the manufacturing yield of the battery.

[0083] In this application, the tensile strength of the connector 5212c has a meaning well known in the art and can be tested using methods and instruments well known in the art. For example, a sample with a length of 100 mm and a width of 15 mm is taken, with an accuracy of 0.05 mm. The sample is symmetrically clamped in the upper and lower clamps of a measuring tool with a spacing of 50 mm between the upper and lower clamps. The measuring tool is started and maintained at a steady speed of (5±1) mm / min. The maximum load at which the sample shears and fails is recorded, and the tensile strength σt of the sample is then calculated according to the following formula: σt = P / (b×d)

[0084] Where P is the maximum load (N), b is the width of the sample (mm), and d is the thickness of the sample.

[0085] In some examples, the tensile strength of the connector 5212c may be, but is not limited to, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa, 250 MPa, 260 MPa, 270 MPa, 280 MPa, 290 MPa, 300 MPa, 310 MPa, 320 MPa, 330MPa, 340MPa, 350MPa, 360MPa, 370MPa, 380MPa, 390MPa, 400MPa or a range consisting of any two of the above values. For example, the tensile strength of the connector 5212c can range from but is not limited to 160MPa-380MPa, 180MPa-340MPa, 200MPa-300MPa, and 220MPa-280MPa.

[0086] In some embodiments of the present application, the elongation at break of the connector 5212c is 3%-10%. When the elongation at break of the connector 5212c is set within the above range, the probability of cracking can be further reduced, which helps reduce the cracking rate of the tab component 5212, thereby improving the manufacturing yield of the battery.

[0087] In the present application, the elongation at break of the connector 5212c has a meaning well known in the art, and can be tested using methods and instruments well known in the art. For example, a sample with a length of 100 mm and a width of 15 mm is taken, accurate to 0.05 mm, and the sample is symmetrically clamped in the upper and lower clamps of the measuring tool, with a distance of 50 mm between the upper and lower clamps. The measuring tool is started and maintained at (5±1) mm / min, and loaded at a stable speed. The gap m between the upper and lower clamps when the sample breaks is recorded, and the elongation at break = (m-50) / 50*100%.

[0088] In some examples, the elongation at break of the connector 5212c may be, but is not limited to, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, 7.0%, 7.1%, 7.2%, 7.3%. , 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8.0%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, 9.0%, 9.1%, 9.2%, 9.3%, 9.4%, 9.5%, 9.6%, 9.7%, 9.8%, 9.9%, 10% or a range consisting of any two of the above values. For example, the elongation at break of the connector 5212c can be in the range of but not limited to 3.1%-9.8%, 3.6%-9.4%, 4%-8.9%, 4.3%-8.4%, 4.0%-8.0%, 4.3%-7.8%, and 4.5%-7.2%.

[0089] In some of the above embodiments, the current collector 5211 can increase the compaction density of the active material layer in the electrode plate 521, thereby helping to improve the volume energy density of the battery. However, when a high-strength substrate is used as the tab 5212a, its high-strength substrate is prone to cracking during the connection process, and the reliability of the connection is low, that is, it is easy to disconnect, which is not conducive to improving the battery manufacturing yield. Therefore, in the present application, a connector 5212c is provided on one side of the tab 5212a, and the tensile strength of the connector 5212c is less than the tensile strength of the current collector 5211, and the transition component 522 is electrically connected to the connector 5212c through the through hole 5212b of the tab 5212a, which can reduce the probability of cracking of the tab component 5212 and improve the reliability of the connection between the transition component 522 and the connector 5212c. Therefore, in the present application, the connector 5212c includes a suitable material to further improve the manufacturing yield of the battery.

[0090] In some embodiments of the present application, the material of the connector 5212c includes one or more of aluminum, nickel, and copper. The material of the connector 5212c including any one or more of the above materials can help reduce the probability of cracking and improve the reliability of its connection with the adapter 522.

[0091] In some embodiments of the present application, the resistivity R2 of the connector 5212c is 0.1×10 -3 Ω / m-2×10 -3 When the resistance of the connector 5212c is set within the above range, the transmission characteristics of electrons in the connector 5212c can be improved, so that the battery has better dynamic performance.

[0092] In this application, the resistivity of the connector 5212c has a meaning well known in the art, and can be tested using methods and instruments well known in the art, such as using a four-probe resistance meter with a probe spacing of 1 mm, a sample size of 100 mm*100 mm, and a test position in the middle of the sample. The resistivity of the sample = instrument display value / sample thickness.

[0093] In some examples, the resistivity R2 of the connector 5212c is 0.1×10 -3 Ω / m, 0.2×10 -3 Ω / m, 0.3×10 - 3 Ω / m, 0.4×10 -3 Ω / m, 0.5×10 -3 Ω / m, 0.6×10 -3 Ω / m, 0.7×10 -3 Ω / m, 0.8×10 -3 Ω / m, 0.9×10 - 3Ω / m, 1.0×10 -3 Ω / m, 1.1×10 -3 Ω / m, 1.2×10 -3 Ω / m, 1.3×10 -3 Ω / m, 1.4×10 -3 Ω / m, 1.5×10 - 3 Ω / m, 1.6×10 -3 Ω / m, 1.7×10 -3 Ω / m, 1.8×10 -3 Ω / m, 1.9×10 -3 Ω / m, 2.0×10 -3 Ω / m or a range consisting of any two of the above values. For example, the resistivity R2 of the connector 5212c may be in the range of, but not limited to, 0.2×10 -3 Ω / m-1.8×10 -3 Ω / m, 0.5×10 -3 Ω / m-1.5×10 -3 Ω / m.

[0094] In some embodiments of the present application, the thickness d1 of the connector 5212c is 5 μm-20 μm. When the thickness of the connector 5212c is set within the above range, it can help it have appropriate mechanical strength, reduce the probability of cracking, and improve the mass energy density of the battery.

[0095] In the present application, the thickness of the connector 5212c has a meaning well known in the art and can be tested using methods and instruments well known in the art, such as a micrometer (e.g., Mitutoyo 293-100, with an accuracy of 0.1 μm).

[0096] In some examples, the thickness d1 of the connector 5212c may be, but is not limited to, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm. , 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, 20μm or a range consisting of any two of the above values. For example, the thickness d1 of the connector 5212c can range from but is not limited to 5.5μm-19μm, 7μm-17μm, and 9μm-15μm.

[0097] In some embodiments of the present application, the electrode tab 521 further includes an active material layer disposed on one side of the current collector 5211, and the distance between the connecting member 5212c and the active material layer is 3 mm - 10 mm. When the distance between the connecting member 5212c and the active material layer is set within the above range, the damage to the active layer caused by the connecting member 5212c or when the connecting member 5212c and the转接部件522 are connected can be reduced.

[0098] In the present application, the distance between the connecting member 5212c and the active material layer refers to the distance between the opposite edges of the connecting member 5212c and the active material layer, and it can be measured by using instruments and methods well-known in the art. For example, it can be directly measured with a ruler or a film ruler, and the accuracy is less than or equal to 0.5 mm.

[0099] In some embodiments of the present application, the distance between the connecting member 5212c and the end of the tab 5212a away from the active material layer is less than or equal to 5 mm. When the distance between the connecting member 5212c and the end of the tab 5212a away from the active material layer is set within the above range, the current-carrying area of the connecting member 5212c can be increased, and at the same time, the energy density of the battery can be increased.

[0100] In the present application, the distance between the connecting member 5212c and the end of the tab 5212a away from the active material layer is less than or equal to 5 mm. It can be understood that the connecting member 5212c does not extend beyond the tab 5212a, and its distance from the end of the tab 5212a away from the active material layer is less than or equal to 5 mm, or the connecting member 5212c extends beyond the tab 5212a, and its distance from the end of the tab 5212a away from the active material layer is less than or equal to 5 mm.

[0101] In some embodiments of the present application, the转接部件522 includes one or more of aluminum, nickel, and copper. This helps the electrical connection between the connecting member 5212c and the转接部件, and further improves the reliability of the connection between the转接部件522 and the connecting member 5212c.

[0102] In some embodiments of the present application, the area S1 of the connecting member 5212c, the area S2 of the tab 5212a, the area S3 of the through hole 5212b, and the contact area S4 between the转接部件522 and the connecting member 5212c satisfy: S4 < S3 < S1 < S2. When S1, S2, S3, and S4 satisfy the above relationship, it can help improve the connection reliability between the转接部件522 and the connecting member 5212c.

[0103] In this application, the area S1 of the connecting member 5212c, the area S2 of the tab 5212a, the area S3 of the through-hole 5212b, and the contact area S4 between the转接部件522 and the connecting member 5212c (i.e., the ultrasonic welding area 5212d in Figure 3) all refer to the surface areas at various locations, which can be measured respectively by methods and instruments well-known in the art. For example, a regular quadrilateral can be directly measured and calculated with a ruler, and an irregular weld mark can be measured by selecting the graphic with a二次元框选图形.

[0104] In order to improve the current-carrying capacity of the tab 5212a, in some embodiments of this application, the area difference S5 between the area of the overlapping part of the connecting member 5212c and the tab 5212a and the area S3 of the through-hole 5212b and the contact area S4 between the connecting member 5212c, the tab 5212a, and the转接部件522 and the connecting member 5212c satisfy: S4*d1*R1 / (d2*R2+d1*R1)<S5<S1, where d1 represents the thickness of the connecting member 5212c, in μm; R1 represents the resistivity of the connecting member 5212c, in mΩ; d2 represents the thickness of the tab 5212a, in μm; R2 represents the resistivity of the tab 5212a, in mΩ. In these above embodiments, when S1, S4, and S5 satisfy the above relationship, it can help improve the current-carrying capacity of the tab component 5212.

[0105] In some embodiments of this application, the number of layers after winding or laminating the current collector 5211 in the electrode assembly is N, and the number of layers of the connecting member 5212c in the tab component 5212 is n, and N and n satisfy: N-1≤n≤N+1.

[0106] In the embodiments of this application, there is no special limitation on the shape of the through-hole 5212b of the tab 5212a. For example, the shape of the through-hole 5212b can be circular, square, etc.

[0107] In addition, in the embodiments of this application, the electrode plate 521 can be one of the positive electrode plate and the negative electrode plate. For the convenience of detailed description of the electrode plate 521 in the embodiments of this application, the following embodiments are described by taking the electrode plate 521 as the negative electrode plate as an example.

[0108] In some embodiments of this application, the positive electrode plate generally includes a positive current collector and a positive active material layer provided on one side of the positive current collector and containing a positive active material.

[0109] In some examples, the positive current collector has two surfaces opposite to each other in its own thickness direction, and the positive active material layer is provided on any one or both of the two opposite surfaces of the positive current collector.

[0110] In some embodiments of the present application, the positive electrode current collector includes a metal foil or a composite current collector. For example, the metal foil may include aluminum foil, and the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. 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 substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0111] In some embodiments of the present application, the positive electrode active material may be a positive electrode active material for a battery that is well known in the art. Exemplarily, the positive electrode active material may include one or more of an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds. However, the embodiments of the present application are not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may 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 as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05O2) and its modified compounds. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, one or more of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0112] In some embodiments of the present application, the positive electrode active material layer may further optionally include a binder. Exemplarily, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0113] In some embodiments of the present application, the positive electrode active material layer may further optionally include a conductive agent. For example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0114] In some embodiments of the present application, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0115] In some embodiments of the present application, the negative electrode plate is the electrode plate 521 in the above embodiment.

[0116] In some embodiments of the present application, at least one side of the negative electrode current collector is provided with a negative electrode active material layer, and the negative electrode active material layer includes a negative electrode active material, wherein the negative electrode active material may adopt negative electrode active materials for batteries known in the art. Exemplarily, the negative electrode active material may include one or more of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials and lithium titanate. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0117] In some embodiments of the present application, the negative electrode active material layer may further optionally include a binder. Exemplarily, the binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0118] In some embodiments of the present application, the negative electrode active material layer may further optionally include a conductive agent, which may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0119] In some embodiments of the present application, the negative electrode membrane active material layer may optionally further include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0120] In some embodiments, the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, a negative electrode collector including a negative electrode active material layer can be obtained; the edge area of ​​the negative electrode collector not coated with the slurry is punched, and the connector 5212c is arranged in the edge area, and then cut to form a plurality of tabs 5212a and a plurality of connectors 5212c, wherein the tensile strength of the connector 5212c is less than the tensile strength of the negative electrode collector.

[0121] In the embodiments of the present application, the battery cells typically also include an electrolyte, which acts as an ion conductor between the positive and negative electrode plates. This application does not specifically limit the type of electrolyte, and the electrolyte can be selected based on needs. For example, the electrolyte can be liquid, gel, or solid.

[0122] In some embodiments of the present application, the electrolyte includes an electrolyte solution including an electrolyte salt and a solvent.

[0123] In some embodiments of the present application, the electrolyte salt may include one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0124] In some embodiments of the present application, the solvent may include one or more of ethylene carbonate, propylene carbonate, ethyl methyl 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, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0125] In some embodiments of the present application, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, and additives that improve battery high or low temperature performance.

[0126] In some embodiments of the present application, the battery cell further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical and mechanical stability can be selected.

[0127] In some embodiments of the present application, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0128] In some embodiments of the present application, the positive electrode sheet, the negative electrode sheet, and the separator can be made into an electrode assembly through a winding process or a lamination process.

[0129] In some embodiments of the present application, a battery cell may include an outer packaging, which may be used to encapsulate the electrode assembly and the electrolyte.

[0130] In some embodiments of the present application, the outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the battery cell may also be a soft shell, such as a pouch-type soft shell. The soft shell may be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0131] The present application has no particular limitation on the shape of the battery cell, which can be cylindrical, square, or any other shape. For example, FIG3 shows a battery cell 5 with a square structure as an example.

[0132] In some embodiments of the present application, referring to Figure 4, the outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can be formed into an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated 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, and those skilled in the art can select according to specific actual needs.

[0133] Method for manufacturing battery cells

[0134] In a second aspect, the present application provides a method for manufacturing a battery cell according to the first aspect of the present application, comprising:

[0135] S1. providing a current collector;

[0136] S2. A plurality of through holes are provided at intervals in the edge region of the current collector, and a connector is provided on at least one side of the edge region, and then cut into a plurality of tabs and a plurality of connectors to obtain an electrode sheet, wherein the tensile strength of the connector is less than or equal to the tensile strength of the current collector;

[0137] S3, winding or stacking the electrode sheets to form tab components;

[0138] S4. Connect the adapter component to the plurality of connectors through the through-holes and assemble them to obtain a battery cell.

[0139] In the manufacturing method of the battery cell provided in the present application, the above-mentioned manufacturing method can reduce the difficulty of connecting the tabs, and can also reduce the occurrence of cracks caused by the connection of the tabs, thereby improving the manufacturing yield and production output of the battery.

[0140] In some embodiments of the present application, providing a current collector in S1 includes:

[0141] S11, preparing a slurry for an electrode sheet: dispersing an active material, a conductive agent, a binder, and any other components in a solvent (e.g., deionized water) to form a slurry;

[0142] S12, coating the slurry on the coating area of ​​the current collector, and obtaining the current collector having the active material layer after drying, cold pressing and other processes.

[0143] In the above embodiments, a plurality of through holes are spaced apart in the edge area of ​​the current collector not coated with the active material layer, and the connector can be arranged in the edge area by adopting a suitable process to improve the connection reliability between the connector and the tab and the manufacturing efficiency of the battery.

[0144] In some embodiments of the present application, the connector is connected to at least one side of the tab by roller welding. Roller welding of the connector to at least one side of the tab not only helps improve the connection reliability between the connector and the tab, but also helps improve battery manufacturing efficiency.

[0145] In some embodiments of the present application, the transition component is connected to multiple connectors by ultrasonic welding. The use of ultrasonic welding can facilitate the electrical connection of the transition component with multiple connectors along the thickness direction, and can also reduce the probability of separation between the transition component and the connector.

[0146] In some embodiments of the present application, S3 includes:

[0147] The positive electrode sheet, the negative electrode sheet and the separator are wound or laminated to form a tab component, wherein the through holes of two adjacent tabs are interconnected, and at least one of the positive electrode sheet and the negative electrode sheet is the above-mentioned electrode sheet.

[0148] Battery

[0149] In a third aspect, the present application provides a battery, comprising the battery cell in the first aspect of the present application or the battery cell manufactured by the manufacturing method of the second aspect of the present application.

[0150] It is understandable that the battery may be a battery module or a battery pack, and the embodiments of the present application do not specifically limit this.

[0151] In some embodiments of the present application, battery cells may be assembled into a battery module. The number of battery cells contained in a battery module may be one or more. The specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0152] FIG5 shows an example battery module 4. Referring to FIG5 , in the battery module 4, multiple battery cells 5 may be arranged sequentially along the length of the battery module 4. Of course, they may also be arranged in any other manner. Furthermore, the multiple battery cells 5 may be secured together using fasteners.

[0153] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0154] In some embodiments of the present application, the above-mentioned battery modules 4 can also be assembled into a battery pack. The number of battery modules 4 contained in the battery pack can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0155] Figures 6 and 7 illustrate an example battery pack 1. Referring to Figures 6 and 7 , the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box comprises an upper case 2 and a lower case 3. The upper case 2 can be positioned over the lower case 3 to form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0156] Electrical devices

[0157] In a fourth aspect, the present application further provides an electrical device, which includes the battery of the third aspect of the present application. The battery may include one or more of the battery cells, battery modules or battery packs provided in the third aspect of the present application. The battery cells, battery modules or battery packs can be used as power sources for electrical devices, or as energy storage units for electrical devices. Electrical devices may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.

[0158] As an electrical device, a battery cell, battery module or battery pack can be selected according to its usage requirements.

[0159] Figure 8 shows an example of an electric device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the secondary battery, a battery pack or battery module can be used.

[0160] Another example device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be lightweight and thin, and may use a battery cell as a power source.

[0161] The examples described below are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the methods or conditions described in the literature within the art or in the product specifications were used. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0162] Example 1

[0163] Preparation of positive electrode

[0164] The positive electrode active material lithium iron phosphate, conductive agent (SP), and binder (PVDF) were added to NMP solvent in a certain mass ratio (96.5:1:2.5) and mixed evenly to obtain a positive electrode slurry;

[0165] The positive electrode slurry is coated on an aluminum foil with a thickness of 13 μm, and after drying, cold pressing and other processes, a positive electrode sheet is obtained.

[0166] Preparation of negative electrode sheet

[0167] The negative electrode active material (graphite + SiOx = 7.5:2.5), thickener (CMC), conductive agent (SP), and binder (SBR) were added to deionized water in a certain mass ratio (94:1.1:1:3.9) and mixed evenly to obtain a negative electrode slurry;

[0168] The negative electrode slurry is coated on a nickel-iron alloy with a thickness of 6 μm (wherein the Ni:Fe element ratio in the nickel-iron alloy is 1:1), and after drying and cold pressing, a negative electrode sheet with a negative electrode active material layer is obtained;

[0169] Punching is performed on the edge of the negative electrode current collector to form a through hole for the tab, wherein the area of ​​the through hole is 150 mm 2 ;

[0170] A copper foil with a thickness of 6 μm is welded to the above-mentioned edge area through a roller welding process, and the copper foil covers the through hole. After die-cutting, multiple tabs and multiple copper foil blocks are formed to obtain a negative electrode sheet.

[0171] Preparation of isolation membrane

[0172] A PE separator with a thickness of 9 μm was used.

[0173] Preparation of electrolyte

[0174] After mixing EC:DEC (3:7), LiPF6 with a concentration of 1 mol / L was added to the mixed solution to obtain an electrolyte.

[0175] Preparation of lithium-ion batteries

[0176] The positive electrode sheet, separator and negative electrode sheet are wound in sequence to form an electrode assembly, wherein the number of layers of the tab is 14; the copper and aluminum metal foils are ultrasonically welded to the connectors in the tab components through the through holes, with a weld area of ​​100mm 2 (Contact area S4); then place the above electrode assembly in an outer package, inject electrolyte and package it to obtain a lithium-ion battery.

[0177] Examples 2-5

[0178] The preparation method is similar to that of Example 1, except for the relevant parameters of the current collector and the tab components, such as the material and tensile strength of the current collector and the material of the connector.

[0179] Comparative Examples 1-3

[0180] The preparation method is similar to that of Example 1, except for the relevant parameters of the current collector and the tab components.

[0181] Test section

[0182] (1) DCR test

[0183] DCR follows the conventional HPPC process, maintaining an ambient temperature of 25°C, and charging and discharging at a rate of 0.33C for 3cls. The 3cl capacity is taken as the standard capacity C0. After charging to 50% SOC, it is discharged at 4C0 for 30s, and the voltage difference before and after is recorded. DCR = voltage difference / current.

[0184] (2) Welding tensile test

[0185] After welding, use a tensile testing machine to clamp the adapter component at one end and the current collector at the other end, and record the force required to completely pull the weld mark apart at a speed of 50 mm / min.

[0186] (3) Capacity retention test

[0187] At 25°C, after charging and discharging at 0.5C / 0.5C for 100cls, the ratio of the capacity to the initial capacity is the capacity retention rate.

[0188] Table 1 lists the relevant parameters and test results of the negative electrode sheets in Examples 1-5 and Comparative Examples 1-3, respectively.

[0189] Table 1

[0190] According to Table 1, the connector is provided on at least one side of the tab, and the tensile strength of the connector is less than the tensile strength of the current collector. Therefore, the adapter component is connected to multiple connectors through the through-holes of the tab, which can improve the reliability of the connection between the adapter component and the connector and reduce the probability of cracking of the tab component, thereby improving the manufacturing yield of the battery.

[0191] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and within the scope of the technical solution of the present application, embodiments having substantially the same structure as the technical idea and exerting the same effects are all included in the technical scope of the present application. In addition, within the scope of the subject matter of the present application, various modifications that can be conceived by those skilled in the art to the embodiments, and other methods constructed by combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A battery cell, comprising: An electrode tab, the electrode tab includes a current collector and an ear component, the ear component includes a plurality of ears and a plurality of connectors, the plurality of ears are stacked in a first direction and connected to the current collector, the ear has a through hole in the first direction, the connector is disposed on at least one side of the ear, and the tensile strength of the connector is less than the tensile strength of the current collector; A转接部件, the转接部件 is connected to the plurality of connectors through the through hole.

2. The battery cell according to claim 1, wherein: The current collector satisfies at least one of the following characteristics: (Ⅰ) The tensile strength of the current collector is 450 MPa - 1500 MPa, and optionally 500 MPa - 800 MPa; (Ⅱ) The fracture elongation rate of the current collector is less than or equal to 2%, and optionally 0.4% - 1.9%; (III) The resistivity R1 of the current collector is 1×10 -3 Ω / m-4.5×10 -3 Ω / m; (Ⅳ) The thickness d1 of the current collector is 5 μm - 20 μm.

3. The battery cell according to claim 1 or 2, wherein: The connector satisfies at least one of the following characteristics: (Ⅰ) The tensile strength of the connector is 150 MPa - 400 MPa; (Ⅱ) The fracture elongation rate of the connector is 2% - 10%; (Ⅲ) The material of the connector includes one or more of aluminum, nickel, and copper; (IV) The resistivity R2 of the connecting member is 0.1×10 -3 Ω / m-2×10 -3 Ω / m; (Ⅴ) The thickness d2 of the connector is 3 μm - 15 μm.

4. The battery cell according to any one of claims 1 to 3, wherein: The electrode tab further includes an active material layer disposed on at least one side of the current collector. In the width direction of the current collector, the distance between the connector and the active material layer is 3 mm - 10 mm.

5. The battery cell according to claim 4, wherein: The distance between the connector and the end of the ear away from the active material layer is less than or equal to 5 mm.

6. The battery cell according to any one of claims 1 to 5, wherein: The area S1 of the connector, the area S2 of the ear, the area S3 of the through hole, and the contact area S4 between the转接部件 and the connector satisfy: S4 < S3 < S1 < S2.

7. The battery cell according to claim 6, wherein: The area difference S5 between the area of the overlapping part of the connector and the ear and the area S3 of the through hole and the contact area S4 between the connector, the ear, and the转接部件 and the connector satisfy: S4 * d1 * R1 / (d2 * R2 + d1 * R1) < S5 < S1, where d1 represents the thickness of the connector in μm; R1 represents the resistance of the connector in mΩ; d2 represents the thickness of the ear in μm; R2 represents the resistance of the ear in mΩ.

8. A method for manufacturing a battery cell according to any one of claims 1 to 7, comprising: Provide a current collector; Intermittently open a plurality of through holes in the edge area of the current collector, and dispose connectors on at least one side of the edge area, and then form a plurality of ears and a plurality of connectors through cutting treatment to obtain an electrode tab, wherein the tensile strength of the connector is less than the tensile strength of the current collector; Perform winding or stacking treatment on the electrode tab to form an ear component; Connect the转接部件 to the plurality of connectors through the through hole and assemble to obtain the battery cell.

9. The manufacturing method according to claim 8, wherein: The connector is connected to at least one side of the ear by roll welding.

10. The manufacturing method according to claim 8 or 9, wherein: The转接部件 is connected to the plurality of connectors by ultrasonic welding. It should be noted that the term "转接部件" in the original text is not clearly defined. You may need to further clarify its specific meaning or provide a more accurate translation according to the actual situation.

11. A battery, comprising the battery cell according to any one of claims 1 to 7 or the battery cell manufactured by the manufacturing method according to any one of claims 8 to 10.

12. An electrical device comprising the battery according to claim 11.

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