Battery, battery pack and electric device

Abstract

The application relates to the technical field of new energy, and discloses a battery, a battery pack and a power utilization equipment, the battery comprising: a shell; a battery core arranged in the shell, the battery core comprising a negative electrode sheet, the negative electrode sheet comprising a negative electrode sheet body and a negative electrode tab arranged on the negative electrode sheet body; the negative electrode tab being adapted to be electrically connected with the shell; the shell comprising Ti elements, the mass element ratio of the Ti elements in the shell being a, a being greater than or equal to 90%; the wall thickness of the shell being b; the surface resistance of the negative electrode sheet being c, and satisfying: 96 <= a*b*c <= 7570. The battery provided by the application controls the relationship among the content of Ti elements in the shell, the wall thickness of the shell and the surface resistance of the negative electrode sheet, and limits a*b*c within the above range, so that the energy density of the battery is improved, the flight speed of a flying car is improved, the battery impedance is reduced, the large-rate discharging performance of the battery is realized, and the endurance and safety of the flying car are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a battery, a battery pack, and an electrical device. Background Technology

[0002] New energy vehicle batteries are generally heavy, and for flying cars that can fly, battery weight has a significant impact on the overall flight capability. Furthermore, flying cars need to balance lightweight design with high-rate discharge capability. Summary of the Invention

[0003] In view of this, the present invention provides a battery, a battery pack, and an electrical device to solve the problem of how to balance lightweight design and high-rate discharge.

[0004] In a first aspect, the present invention provides a battery comprising:

[0005] case;

[0006] The battery cell is disposed within a housing. The battery cell includes a negative electrode plate, which includes a negative electrode plate body and a negative electrode tab disposed on the negative electrode plate body. The negative electrode tab is adapted to be electrically connected to the housing.

[0007] The shell contains Ti, and the mass percentage of Ti in the shell is a, which is greater than or equal to 90%. The wall thickness of the shell is b, in mm. The sheet resistance of the negative electrode is c, in milliohms. The following conditions must be met: 96 ≤ a·b·c ≤ 7570.

[0008] Beneficial effects: By controlling the relationship between the content of Ti element in the shell, the wall thickness of the shell, and the surface resistance of the negative electrode, and limiting a·b·c within the above range, the shell can be made lighter, and the energy density of the battery can be improved. On the other hand, the lithium-ion and electron transport capabilities of the battery can be improved, the battery impedance can be reduced, and the high-rate discharge performance of the battery can be achieved, effectively improving the range and safety of the flying car.

[0009] Secondly, the present invention also provides a battery pack, including a battery housing and a battery as described above disposed within the battery housing.

[0010] Thirdly, the present invention also provides an electrical device, including an electrical device body and a battery pack as described above disposed on the electrical device body. Attached Figure Description

[0011] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0012] Figure 1 This is an exploded view of the battery in this invention when it is a tetragonal prism battery. Figure 1 ;

[0013] Figure 2 This is an exploded view of the battery in this invention when it is a tetragonal prism battery. Figure 2 ;

[0014] Figure 3 This is a schematic diagram of the negative electrode sheet of the present invention;

[0015] Figure 4 This is a schematic diagram of the battery cell of the present invention. Figure 1 ;

[0016] Figure 5 This is a schematic diagram of the battery cell of the present invention. Figure 2 ;

[0017] Figure 6 This is an exploded view of the present invention when the battery is a cylindrical battery;

[0018] Figure 7 This is a schematic diagram of the first end face of the battery of the present invention when it is a cylindrical battery;

[0019] Figure 8 This is a schematic diagram showing the unfolded state of the negative electrode sheet when the battery of the present invention is a cylindrical battery;

[0020] Figure 9 This is a cross-sectional view of the negative electrode sheet of the present invention.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Shell; 11. Shell body; 12. Cover plate;

[0023] 2. Battery cell; 20. Battery cell body; 201. First end face; 21. Negative electrode sheet; 211. Negative electrode sheet body; 2111. Current collector layer; 21111. Polymer layer; 21112. Metal layer; 2112. Negative electrode active material layer; 212. Negative electrode tab; 2120. Sub-electrode tab; 213. Tabletless region; 214. Tab group; 222. Positive electrode tab; 24. Core winding hole. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] Batteries for new energy vehicles are generally heavy, and for flying cars that can fly, battery weight has a significant impact on the vehicle's flight capability. In related technologies, the battery casing is often made of steel to meet the requirements of high strength and high safety performance. However, steel casings have a high density, which can easily increase the overall weight of the battery pack.

[0029] Because metallic titanium (Ti) has a low density, adding a certain proportion of Ti into the casing can reduce its weight, achieving lightweighting. However, increasing the Ti content results in relatively poor conductivity of the casing, affecting the battery's high-rate discharge capability. For flying cars, sufficient lightweighting is necessary while still enabling the battery to discharge at high rates to support rapid takeoff and landing and maintain flight capability.

[0030] The following is combined Figures 1 to 9 The following describes embodiments of the present invention.

[0031] According to an embodiment of the present invention, a battery is provided, comprising:

[0032] Casing 1;

[0033] The battery cell 2 is disposed inside the housing 1. The battery cell 2 includes a negative electrode plate 21. The negative electrode plate 21 includes a negative electrode plate body 211 and a negative electrode tab 212 disposed on the negative electrode plate body 211. The negative electrode tab 212 is adapted to be electrically connected to the housing 1.

[0034] The shell 1 contains Ti element, and the mass percentage of Ti element in the shell 1 is a, where a is greater than or equal to 90%; the wall thickness of the shell 1 is b, in mm; the surface resistance of the negative electrode 21 is c, in milliohms; satisfying: 96 ≤ a·b·c ≤ 7570.

[0035] It should be noted that the battery in this application is a secondary battery, also known as a rechargeable battery or storage battery, which refers to a battery that can be used again after being discharged by recharging to activate the active materials.

[0036] Typically, a secondary battery consists of a battery cell, an electrolyte, and a casing. The battery cell includes a positive electrode, a negative electrode, and a separator. The battery cell and electrolyte are assembled inside the casing. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, located between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, situated between the positive and negative electrodes, mainly serves to conduct active ions.

[0037] As an example, the preparation process of a secondary battery is as follows: the positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, the electrodes are wound or stacked to obtain a cell. The cell is placed in a casing, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a secondary battery is obtained.

[0038] The positive electrode, negative electrode, electrolyte, and separator are described in turn below:

[0039] [Positive electrode tablets]

[0040] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector. The positive electrode film layer includes a positive electrode active material, which can be any existing publicly disclosed positive electrode active material or a positive electrode active material optimized based on existing materials.

[0041] This application does not impose any particular restrictions on the type of positive electrode active material for the positive electrode sheet. As an example, the positive electrode active materials in this application include lithium-containing transition metal oxides (e.g., LiCoO2), phosphides (e.g., LiFePO4), or lithium intercalation compounds (e.g., positive electrode materials for binary lithium batteries such as lithium cobalt oxide and lithium nickel oxide, or positive electrode materials for ternary lithium batteries such as lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide).

[0042] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, rolling, cutting and other processes.

[0043] In this application, the binder is used to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. This application does not impose any particular limitation on the type of binder for the positive electrode sheet; the binder can be any conventional choice in the battery industry. Specifically, the binder can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polyimide (PI), polyacrylic acid (PAA), polyacrylate, polyolefin, sodium carboxymethyl cellulose (CMC), or sodium alginate.

[0044] This application does not impose any particular restrictions on the positive electrode current collector, as long as it is conductive and will not cause adverse chemical changes in the battery, and can be made of, for example: stainless steel, aluminum, nickel, titanium, sintered carbon; or aluminum or stainless steel that has been surface treated with one of carbon, nickel, titanium, silver, etc.

[0045] [Negative electrode plate]

[0046] The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. The negative electrode active material layer comprises a silicon-based material. This application does not specifically limit the type of silicon-based material; the silicon-based material can be a silicon-carbon material and / or a silicon-oxygen material. As an example, the silicon-based material can be one or more of silicon-carbon composite negative electrode materials, silicon suboxide negative electrode materials, modified silicon suboxide negative electrode materials, and nano-silicon materials. The negative electrode active material in the negative electrode active material layer may also optionally include one or more of artificial graphite, natural graphite, and hard carbon.

[0047] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, rolling, cutting and other processes.

[0048] This application does not specifically limit the type of negative electrode conductive agent. In some embodiments, as an example, the negative electrode conductive agent can be one or more of conventional negative electrode conductive agents such as acetylene black and carbon nanotubes. This application does not specifically limit the type of negative electrode binder. In some embodiments, as an example, the binder can be one or more of conventional negative electrode binders such as styrene-butadiene rubber latex (SBR), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and sodium carboxymethyl cellulose (CMC). In this application, the binder is preferably PAA, SBR, and CMC, and the mass ratio of PAA, SBR, and CMC can be (34.38-74.29):(20-59.38):(5-7.14).

[0049] This application does not impose specific limitations on the type of negative electrode current collector. In some embodiments, as an example, the negative electrode current collector can be one of the conventional negative electrode current collectors such as copper foil.

[0050] Electrolyte

[0051] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. As an example, the electrolyte in this application can be any electrolyte suitable for electrochemical energy storage devices in the art. The electrolyte includes an electrolyte and a solvent; the electrolyte typically includes a lithium salt, and additives may also be added to the electrolyte.

[0052] Specifically, the lithium salt includes at least one selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be 0.5–5 mol / L.

[0053] Specifically, the solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0054] In some implementations, as an example, the additive may be a conventional electrolyte additive such as fluoroethylene carbonate (FEC), chloroethylene carbonate (CEC), or vinylene carbonate (VC).

[0055] [Septum]

[0056] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0057] In some embodiments, as an example, the diaphragm can be one of PP, PE, or PP / PF; the diaphragm can also be a structure in which a coating is formed on the surface of the base film, wherein the base film coating can be one of PP, PE, or PP / PF, and the coating can be an inorganic coating and / or an organic coating. The inorganic coating can be selected from alumina ceramic layers, osmium silicate, etc., and the organic coating can be selected from PVDF, etc.

[0058] It should be noted that the battery cell 2 includes tabs, specifically positive and negative tabs 212. As a key component of the battery, the tabs are used to transmit and extract the internal current of the battery cell. The material of the tabs can be the same as that of the current collector. For example, the tabs can be made of at least one of the following: silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon, or titanium. Furthermore, the tabs can be cut from the current collector or be separately formed metal parts. It is understood that the positive tab is electrically connected to the positive electrode plate in the battery cell body 20, and the negative tab is electrically connected to the negative electrode plate in the battery cell body 20. The material of the negative tab 212 can be copper or a copper alloy.

[0059] In this embodiment, the battery cell 2 includes a negative electrode plate 21, which extends into a negative electrode tab 212. The negative electrode tab 212 is adapted to be electrically connected to the housing 1.

[0060] The shell 1 includes Ti, which significantly reduces weight while maintaining high strength, achieving lightweight design, improving battery energy density, and contributing to increased flight speed.

[0061] However, increasing the Ti content results in relatively poor conductivity of the casing 1, leading to a decrease in the current flow capacity between the negative electrode tab 212 and the casing 1, thus affecting the battery's high-rate discharge capability. By controlling the casing wall thickness and the sheet resistance of the negative electrode 21, the current transmission path and lithium-ion transport rate can be improved, thereby helping to achieve the battery's high-rate charging capability.

[0062] The mass percentage of Ti in shell 1 is 'a'. In this embodiment, the method for determining the content of Ti in shell 1 can be X-ray fluorescence spectrometry, as detailed below:

[0063] (1) Sample preparation: First, the shell sample 1 needs to be properly treated to facilitate X-ray penetration and excitation of fluorescence. This includes steps such as cutting, grinding, and polishing to ensure that the sample surface is flat and free of contamination.

[0064] (2) X-ray excitation: High-energy X-rays are used to irradiate the sample surface to excite the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the types of elements, thus allowing us to determine which elements are contained in the sample.

[0065] (3) Spectral collection and analysis: X-rays reflected from the sample surface and fluorescence spectra emitted are collected using a spectrometer. The type and content of elements can be determined by the position and intensity of characteristic spectral lines.

[0066] (4) Matrix effect correction: Due to the interaction between various elements in shell 1 (matrix effect), the collected spectral data needs to be corrected to eliminate the influence of this interaction on the analysis results and improve the accuracy of the analysis.

[0067] (5) Interpretation of results: Based on the corrected data, the content of each element in shell 1 can be calculated, and then the mass ratio of Ti element in shell 1 can be obtained as a.

[0068] Furthermore, controlling the Ti element content helps to achieve a lighter casing, further improving the energy density of the battery, which can increase its flight speed when applied to flying cars.

[0069] The sheet resistance of the negative electrode 21 is c. In this embodiment, the sheet resistance of the negative electrode 21 is measured as follows:

[0070] (1) Discharge the battery at 0.33C to the lower limit voltage (the lower limit voltage is determined by the system; for a system with lithium iron phosphate as the positive electrode and graphite as the negative electrode, the lower limit voltage is 2.5V; for a system with nickel-cobalt-manganese ternary material as the positive electrode and graphite as the negative electrode, the lower limit voltage is 2.5V; for other systems such as lithium nickel manganese oxide as the positive electrode and graphite as the negative electrode, the lower limit voltage is 3.5V). Remove the empty battery, disassemble the battery, remove the negative electrode sheet, soak the negative electrode sheet in DMC (dimethyl carbonate) solution for 2 hours, and then air dry it.

[0071] (2) Cut the test membrane into 14mm round pieces;

[0072] (3) Using the instrument, rotate the black button on the lower right of the mold counterclockwise, and the upper probe will descend to the sample surface. When the pressure reaches 0.4 MPa, read the resistance and pressure, and then obtain the sheet resistance c of the negative electrode 21; the specific instrument used is: ACCFILM film resistance tester.

[0073] The sheet resistance of the negative electrode 21 affects the lithium-ion transport capability and electron transport capability, which in turn affects the battery impedance and consequently the battery's charge and discharge capability under high-rate conditions.

[0074] This application does not limit the method of adjusting the sheet resistance of the negative electrode 21. Specifically, it can be adjusted by the particle size of the negative electrode active material, the compaction density of the negative electrode, the content of the conductive agent, etc.

[0075] The wall thickness of housing 1 affects the current path between the tab and the housing. By controlling the wall thickness b of housing 1, the current transmission path can be improved, the battery impedance can be reduced, and the high-rate discharge capability of the battery can be enhanced.

[0076] This application does not limit the testing method for the shell wall thickness; it can be tested using conventional measurement methods.

[0077] Alternatively, the battery can be a cylindrical battery or a prism-shaped battery. The battery can be manufactured in a wound form or a stacked form.

[0078] The battery provided in the embodiments of the present invention achieves lightweight casing and improves battery energy density by controlling the relationship between the content of Ti element in the casing 1, the wall thickness of the casing 1 and the sheet resistance of the negative electrode 21, and limiting a·b·c within the above range. On the other hand, it improves the lithium-ion and electron transport capabilities of the battery, reduces battery impedance, achieves high-rate discharge performance of the battery, and effectively improves the range and safety of flying cars.

[0079] By comprehensively controlling the three parameters a, b, and c, it is possible to ensure lightweight design while also achieving high-rate discharge, improving conductivity, and meeting the battery performance requirements of flying cars.

[0080] For example, in this embodiment, the value of a·b·c can be 96 or 150 or 350 or 640 or 1500 or 2511 or 3642 or 4321 or 5363 or 6421 or 7570, or it can be any range formed by any two of the above values.

[0081] The negative electrode sheet 21 extends into a negative electrode tab 212, which serves as the connection point between the negative electrode sheet 21 and the housing 1. This tab 212 must ensure good electrical contact and conductivity. In this embodiment, the electrical connection between the negative electrode tab 212 and the housing 1 ensures smooth current transmission and avoids battery performance degradation due to poor connection. Furthermore, the sheet resistance c of the negative electrode sheet 21 is an important indicator of its conductivity. The sheet resistance reflects the interfacial resistance between the negative electrode material and the electrolyte, affecting electron transport during charging and discharging, and thus impacting the battery's discharge capacity. By precisely controlling the sheet resistance c, the overall battery performance can be further optimized.

[0082] Referring to Table 1 below, the provided battery was subjected to mass energy density testing and limiting current testing through several embodiments and comparative tests to verify its qualification.

[0083] Table 1

[0084]

[0085] Regarding Table 1 above, the explanation is as follows:

[0086] Performance 1. Mass energy density test, the method is as follows: (1) Charge the battery at a constant current of 0.33C to the upper limit voltage, then charge at a constant voltage until the cutoff current is less than or equal to 0.05C, and then discharge at 0.33C to the lower limit voltage; repeat the above steps 3 times, and take the discharge energy of the third discharge as the discharge energy E of the battery; (2) Weigh the battery by an electronic balance to obtain the weight M; (3) Calculate the mass energy density: E / M, unit Wh / Kg. When the mass energy density is greater than or equal to 300Wh / kg, its mass energy density is better and meets the actual working conditions.

[0087] Performance 2, Limiting Current Test: The method is as follows: At 25℃, first charge at a constant current of 0.33C to the upper limit voltage, then charge at a constant voltage until the current is less than or equal to 0.05C, then discharge at 0.33C to the lower limit voltage. Repeat this cycle for 3 cycles to obtain the fixed capacity C. Then charge at 0.33C to the upper limit voltage, with the cutoff current less than or equal to 0.05C, then discharge at 0.33C to 50% SOC, then let stand for 2 hours, and then discharge to the lower limit voltage in 10 seconds. Record the current at this time. When the current is between 10C and 14.2C, it is considered qualified.

[0088] Regarding the test results, referring to Table 1 above, the explanation is as follows:

[0089] As shown in Examples 1-19, when the formula for a·b·c is within the range of 96-7570, the battery's energy density is greater than 300Wh / kg according to the mass energy density test, and the battery's limiting current is within the range of 10C-14.2C according to the limiting current test, meeting the performance requirements and satisfying the battery's ability to discharge at high rates. In Comparative Examples 1 and 3, the formula for a·b·c exceeds the upper limit, and the battery's limiting current is less than the lower limit of 10C according to the limiting current test, indicating weak high-rate capability and failing to meet the performance requirements. In Comparative Example 2, the formula for a·b·c exceeds the lower limit, and the battery's energy density is less than 300Wh / kg according to the mass energy density test, failing to meet the performance requirements.

[0090] Furthermore, it should be noted that the preparation of the example batteries and comparative batteries includes the following steps:

[0091] (1) Preparation of the positive electrode:

[0092] The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, it is cold-pressed and slit to obtain the positive electrode sheet. Specifically, the mass ratio of positive electrode material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0093] (2) Preparation of negative electrode:

[0094] The negative electrode active material graphite, conductive agent acetylene black, thickener CMC, and binder SBR are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained. The ratio of negative electrode graphite: conductive agent: thickener: binder is (90~96): (4~2): (2~1): (4~1).

[0095] (3) Preparation of electrolyte:

[0096] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0097] (4) Preparation of the diaphragm:

[0098] Polyethylene film is selected as the diaphragm.

[0099] (5) Preparation of lithium-ion batteries:

[0100] The above-mentioned positive electrode sheet, separator, and negative electrode sheet are stacked in sequence, and then wound or stacked to obtain a bare cell. The bare cell is placed in an outer packaging shell, dried, injected with electrolyte, and then packaged, left to stand, formed, and calibrated to obtain a lithium-ion battery.

[0101] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt and manganese, and lithium manganese iron phosphate.

[0102] The negative electrode active material can be selected from one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0103] In this application, the positive electrode active material is selected from a nickel-cobalt-manganese ternary system, with the structural formula LiNi. 0.9 Co 0.05 Mn 0.05 Taking O2 as an example, the mass percentage of the conductive agent is shown in the table. The sum of the mass percentages of the positive electrode material, binder, and conductive agent is 100%. The main negative electrode material is selected from artificial graphite. Optionally, in other embodiments, the main positive electrode material can be selected from one or more of other nickel-cobalt-manganese ternary materials, lithium iron phosphate, and lithium manganese iron phosphate; the negative electrode can also include one or more of silicon-carbon negative electrode or natural graphite. In conjunction with the selection of the main positive and negative electrode materials, the mass energy density test, and the limiting current test, the upper limit voltage corresponds to 4.25V, and the lower limit voltage corresponds to 2.5V.

[0104] In some embodiments, combined with Figure 1 As shown, the battery cell 2 is a quadrangular prism battery cell. The battery cell 2 includes a battery cell body 20, and a negative electrode tab 212 extends from the battery cell body 20 along the first end face 201 in the first direction. The negative electrode tab 212 is disposed at the center position of the first end face 201 along the second direction. The second direction is perpendicular to the first direction.

[0105] The distances between the two ends of the negative electrode tab 212 along the second direction and the two end faces of the cell body 20 along the second direction are d1 and d2, respectively, and satisfy: d1=d2; at this time, c satisfies: 2 milliohms≤c≤40 milliohms.

[0106] The negative electrode tab 212 is located at the center of the first end face 201 along the second direction. It should be noted that the center position refers to the position range of the first end face in the second direction, corresponding to 1 / 3 to 2 / 3 of the length.

[0107] By positioning the negative electrode tab 212 at the center of the first end face 201 along the second direction, good current uniformity is achieved at both ends of the electrode, ensuring uniform current distribution, reducing battery impedance, and contributing to improved high-rate discharge capability. Furthermore, by controlling the surface resistance c of the negative electrode 21 within the aforementioned range, lithium-ion transport capability is further optimized, battery impedance is reduced, and better high-rate discharge capability is achieved.

[0108] In some embodiments, combined with Figure 1 or Figure 2 As shown, the battery cell 2 includes a battery cell body 20, and a negative electrode tab 212 extends from the battery cell body 20 along the first end face 201 in the first direction;

[0109] The distances between the two ends of the negative electrode tab 212 along the second direction and the two end faces of the cell body 20 along the second direction are d1 and d2, respectively; wherein, the second direction is perpendicular to the first direction;

[0110] The dimension of the first end face 201 along the second direction is e, which satisfies: 0.6≤(d1+d2) / e≤0.9.

[0111] By controlling d / e within the above range, the current distribution can be effectively balanced, avoiding excessively long paths for current to travel from the edge of the negative electrode 21 to the tab, thereby reducing resistance loss and further lowering internal resistance, which is beneficial to improving the battery's high-rate discharge capability.

[0112] For example, in this embodiment, the value of (d1+d2) / e can be 0.6, 0.7, 0.8, or 0.9, or it can be any range formed by any two of the above values.

[0113] In other embodiments, combined with Figure 2 As shown, the battery cell 2 includes a battery cell body 20, and a negative electrode tab 212 extends from the battery cell body 20 along the first end face 201 in the first direction;

[0114] The distances between the two ends of the negative electrode tab 212 along the second direction and the two end faces of the cell body 20 along the second direction are not equal; wherein, the second direction is perpendicular to the first direction; at this time, c satisfies: 1 milliohm ≤ c ≤ 35 milliohm.

[0115] When the distances between the two ends of the negative electrode tab 212 along the second direction and the two end faces of the cell body 20 along the second direction are not equal, the current path at the edge of the negative electrode sheet on the side furthest from the negative electrode tab 212 is likely to be longer, resulting in increased current transmission impedance and thus affecting the overall discharge efficiency of the battery. By further controlling the c value, the high-rate discharge capability of the battery can be effectively improved, the impedance of the negative electrode sheet edge area can be reduced, ensuring smoother current transmission and avoiding increased battery impedance that would affect the battery's discharge capability.

[0116] In some embodiments, combined with Figure 1 or Figure 2 As shown, the distances between the two ends of the negative electrode tab 212 along the second direction and the two end faces of the battery cell body 20 along the second direction are d1 and d2, respectively, satisfying: 0.5≤d1 / d2<1 or 1<d1 / d2≤1.5.

[0117] By controlling the d1 / d2 ratio, the current distribution on the negative electrode 21 can be optimized, avoiding a long current transmission path at the edge of one side of the cell, preventing an increase in resistance on one side, thereby reducing resistance loss on that side, further improving the overall discharge performance of the battery, and contributing to the improvement of the battery's high-rate discharge capability.

[0118] For example, in this embodiment, the value of d1 / d2 can be 0.5, 0.7, 0.9, 1.1, 1.3, or 1.5, or it can be any range formed by any two of the above values.

[0119] In some embodiments, combined with Figure 1 As shown, the battery cell 2 includes a battery cell body 20, and a negative electrode tab 212 extends from the battery cell body 20 along the first end face 201 in the first direction;

[0120] The dimension of the negative electrode tab 212 along the second direction is f, and the dimension of the first end face 201 along the second direction is e, satisfying: f < e; at this time, c satisfies: 1 milliohm ≤ c ≤ 30 milliohm.

[0121] In this embodiment, the width of the negative electrode tab 212 along the second direction is smaller than the width of the first end face 201 along the second direction, which will make the tab's current carrying capacity weak and increase the local resistance. By further controlling the surface resistance of the negative electrode sheet 21, the local resistance can be reduced, the tab's current carrying capacity can be improved, and the battery's high-rate discharge capacity can be improved.

[0122] In some other embodiments, the battery cell 2 includes a battery cell body 20, and a negative electrode tab 212 extends from the first end face 201 of the battery cell body 20 along a first direction.

[0123] The dimension of the negative electrode tab 212 along the second direction is f, and the dimension of the first end face 201 along the second direction is e, satisfying: f=e; at this time, c satisfies: 2.5 milliohms ≤ c≤35 milliohms.

[0124] By making the dimension of the negative electrode tab 212 along the second direction equal to the dimension of the first end face 201 along the second direction, the current-carrying capacity of the tab can be maximized, local resistance can be reduced, and uniform current distribution can be ensured. By further controlling the surface resistance of the negative electrode sheet 21, the stability and efficiency of the battery under high-rate discharge conditions can be further improved, ensuring optimal overall performance.

[0125] In some embodiments, combined with Figure 5 As shown, the battery cell 2 is a cylindrical battery cell. The battery cell 2 includes a battery cell body 20, from which a positive electrode tab 222 and a negative electrode tab 212 extend. The positive electrode tab 222 and the negative electrode tab 212 are located on the same side of the battery cell body 20 along the first direction. At this time, c satisfies: 1.5 milliohms ≤ c ≤ 32 milliohms.

[0126] The positive electrode tab 222 and the negative electrode tab 212 are located on the same side of the cell body 20 along the first direction, i.e., the cell axis. Although this helps to reduce internal space occupation and improve the overall compactness of the battery, the fact that the positive electrode tab 222 and the negative electrode tab 212 are arranged on the same side requires two types of tabs to be arranged on the same end face of the cell body 20. This limits the size of the tabs and results in weak overcurrent capacity of a single polarity tab. By further controlling the surface resistance c of the negative electrode sheet 21, the current transmission impedance of the negative electrode sheet can be reduced, thereby improving the high-rate discharge capability of the battery.

[0127] Based on the above embodiments, the positive electrode tab 222 and the negative electrode tab 212 are located on the same side of the cell body 20 along the first direction, combined with Figure 6 As shown, cell 2 includes a cylindrical cell; the diameter of cell 2 is g, which satisfies: g≤50mm; at this time, c satisfies: 1.5 milliohms≤c≤27 milliohms.

[0128] The positive electrode tab 222 and the negative electrode tab 212 are arranged on the same side. This requires arranging two types of tabs on the same end face of the cell body 20, which limits the tab size and results in weak current-carrying capacity for each polarity. Furthermore, when the cell 2 is a cylindrical cell, the current-carrying capacity of the tabs is further limited due to the inherent limitations of the cylindrical structure. By controlling the surface resistance c of the negative electrode 21, the current transmission impedance of the negative electrode can be reduced, improving the battery's high-rate discharge capability.

[0129] For example, in this embodiment, the value of g can be 30mm, 40mm, or 50mm, or it can be any range formed by any two of the above values.

[0130] In other embodiments, combined with Figure 4 As shown, the battery cell 2 includes a battery cell body 20, from which a positive electrode tab 222 and a negative electrode tab 212 extend. The positive electrode tab 222 and the negative electrode tab 212 are located on both sides of the battery cell body 20 along the first direction. At this time, c satisfies: 2 milliohms ≤ c ≤ 35 milliohms.

[0131] The positive electrode tab 222 and the negative electrode tab 212 are arranged on opposite sides, which can avoid the tab size limitation, ensure the size of the tab of a single polarity, thereby improving the overcurrent capacity of the tab of a single polarity, reducing local resistance, optimizing current distribution, and further improving the stability of the battery under high-rate discharge conditions by further controlling the surface resistance of the negative electrode 21, reducing current transmission impedance, and improving the battery's high-rate discharge capability.

[0132] In some embodiments, combined with Figure 7 , Figure 8 As shown, the battery cell 2 includes a cylindrical battery cell; the battery cell 2 includes multiple layers of negative electrode sheets 21, each layer of negative electrode sheet 21 includes multiple sub-electrode tabs 2120 distributed along the circumferential direction; in the same layer of negative electrode sheet 21, there is a gap between adjacent sub-electrode tabs 2120, and c satisfies: 1.5 milliohms ≤ c ≤ 25 milliohms.

[0133] When cell 2 is a cylindrical cell, in order to achieve smooth winding of the cylindrical cell, each layer of negative electrode sheet 21 includes multiple sub-tabs 2120, with gaps between adjacent sub-tabs 2120, to avoid wrinkles in the tabs during winding. However, due to the increased number of sub-tabs, the welding effect will be poor when the tabs are subsequently welded to the casing or current collector, affecting the current flow between the tabs and the casing. By further controlling the surface resistance c of the negative electrode sheet 21, the current transmission impedance of the negative electrode sheet can be reduced, improving the high-rate discharge capability of the battery.

[0134] In some embodiments, the circumferential dimension of a single sub-pole tab 2120 is m, satisfying: 2mm≤m≤8mm.

[0135] In some embodiments, combined with Figure 8 As shown, the battery cell 2 includes a cylindrical battery cell; the battery cell 2 includes multiple layers of negative electrode sheets 21, each layer of negative electrode sheet 21 includes multiple sub-electrode tabs 2120 distributed circumferentially; when the negative electrode sheet 21 is in the unfolded state, the multiple sub-electrode tabs 2120 of the same layer constitute a tab group 214, and in the length direction after the negative electrode sheet 21 is unfolded, the negative electrode sheet 21 includes a tabless region 213, the tabless region 213 is formed in the area of ​​the negative electrode sheet 21 where the tab group 214 is not provided, and c satisfies: 1 milliohm ≤ c ≤ 28 milliohm.

[0136] It should be noted that the tabless region 213 does not include the gap between adjacent sub-tabs 2120. In the unwound state of the core, the tabless region can be located at the beginning, end, or middle part of the electrode sheet. It should be noted that the beginning of the electrode sheet refers to the starting end of the winding after the core is unwound; the end of the electrode sheet refers to the ending end of the winding after the core is unwound.

[0137] Since the cylindrical cell includes a winding hole 24, the tabless area 213 prevents the tabs from blocking the winding hole 24. The tabs primarily transmit the cell current; the tabless area reduces the current-carrying capacity of the electrode, decreasing the area of ​​the cylindrical cell available for current carrying and thus impairing current transmission. This embodiment reduces the current transmission impedance by controlling the surface resistance c of the negative electrode 21 within the aforementioned range, preventing further impact on the battery's high-rate discharge capability.

[0138] In some embodiments, combined with Figure 8 As shown, the total length of the electrodeless region 213 is h, which satisfies: h = h1 + h2 + ... + hn, where hn is the length of one segment of the electrodeless region 213 and n is the number of electrodeless regions 213; the length of the negative electrode plate 21 in the unfolded state is j, which satisfies: 0.05 ≤ h / j ≤ 0.2.

[0139] By precisely controlling the length ratio of the tabless region 213, the cylindrical cell is used for overcurrent processing to the maximum extent possible, while ensuring that the cell winding does not block the winding hole 24, thus avoiding affecting the battery's high-rate discharge capability.

[0140] For example, in this embodiment, the value of h / j can be 0.05, 0.1, or 0.2, or it can be any range formed by any two of the above values.

[0141] In some embodiments, the battery cell 2 includes a tab, the tab includes copper, and the copper content accounts for more than or equal to 99% of the total elements in the tab.

[0142] The tabs are used for electrical connection with the housing 1. The welding effect of copper and titanium housing is better, which helps to improve the overcurrent capacity between the tabs and the housing 1, thereby reducing the battery impedance and improving the battery's high-rate charge and discharge capacity.

[0143] In some embodiments, the battery includes a current collector for electrical connection with the negative electrode tab 212 and the housing 1. The current collector includes copper, and the copper content accounts for more than or equal to 99% of the total elements in the current collector.

[0144] Both the current collector and the tabs contain copper. The tabs are first welded to the current collector, and then the current collector is welded to the casing. The welding effect of copper and titanium casing is better, which improves the welding reliability, thereby improving the current carrying capacity, reducing the battery impedance, and improving the battery's high-rate charge and discharge capability.

[0145] In some embodiments, the surface of the manifold includes copper oxide with a thickness ranging from 1 micrometer to 10 micrometers.

[0146] Copper oxide has poorer conductivity compared to copper, so its thickness needs to be controlled. This is to reduce its impact on the battery's overcurrent capacity, and consequently, its high-rate discharge capability.

[0147] In some embodiments, the battery includes terminals, and the cell 2 further includes a positive electrode plate, which includes a positive electrode tab and is electrically connected to the terminals. The positive electrode tab is made of aluminum or an aluminum alloy.

[0148] In some embodiments, combined with Figure 9 As shown, the negative electrode body 211 includes a current collector layer 2111 and a negative electrode active material layer 2112. The thickness of the current collector layer 2111 is k1, and the thickness of the negative electrode active material layer 2112 is k2, satisfying k1 / k2≤0.03. At this time, c satisfies: 1.5 milliohms≤c≤40 milliohms.

[0149] By controlling the ratio of the thickness k1 of the current collector layer 2111 to the thickness k2 of the negative electrode active material layer 2112 to be less than or equal to the above range, the thickness occupied is reduced, thereby increasing the battery capacity. However, when the upper limit of the k1 / k2 ratio is small, the overall thickness of the negative electrode sheet is limited, which makes the current transmission capability of the negative electrode sheet worse. By controlling the sheet resistance c of the negative electrode sheet 21 within the above range, the current transmission impedance can be reduced, the current transmission capability of the negative electrode sheet 21 can be improved, and further impact on the high-rate discharge capability of the battery can be avoided.

[0150] For example, in this embodiment, the value of k1 / k2 can be 0.01, 0.02, or 0.03, or it can be any range formed by the two values ​​mentioned above.

[0151] In some embodiments, combined with Figure 9 As shown, the current collector layer 2111 includes a polymer layer 21111 and a metal layer 21112, and c satisfies: 1.8 milliohms ≤ c ≤ 30 milliohms.

[0152] The current collector layer 2111 comprises a polymer layer 21111 and a metal layer 21112, meaning it is a composite current collector. The polymer layer 21111 further occupies thickness space, resulting in a relative reduction in the thickness of the metal layer 21112, thus weakening the current transport capability of the current collector layer 2111. By controlling the sheet resistance c of the negative electrode 21 within the aforementioned range, the current transport impedance can be reduced, improving the current transport capability of the negative electrode 21 and preventing further impact on the battery's high-rate discharge capability.

[0153] The polymer layer 21111 is made of polymer materials, including at least one of the following: polyamide (PA), polyterephthalate, polyimide (PI), polyethylene (PE), polypropylene (PP), polystyrene (PPE), polyvinyl chloride (PVC), aramid, acrylonitrile-butadiene-styrene copolymer (ABS), polybutylene terephthalate (PET), poly(p-phenylene terephthalamide) (PPTA), polypropylene (PPE), polyoxymethylene (POM), epoxy resin, phenolic resin, polytetrafluoroethylene (PTEE), polyvinylidene fluoride (PVDF), silicone rubber, polycarbonate (PC), polyvinyl alcohol (PVA), polyethylene glycol (PEG), cellulose, starch, protein, their derivatives, their crosslinks, and their copolymers; the metal layer 21112 includes aluminum, copper, nickel, etc.

[0154] In some embodiments, combined with Figure 9 As shown, the thickness of the polymer layer 21111 is k11, and the thickness of the current collector layer 2111 is k12, satisfying: 0.1≤k11 / k12≤0.8.

[0155] By controlling the ratio of k11 / k12 within the aforementioned range, the conductivity of the current collector layer 2111 can be optimized. While meeting the functional requirements of the polymer layer, the thickness occupied by the polymer layer is reduced, ensuring the current transmission capability of the current collector layer 2111 and avoiding impact on the battery's high-rate discharge capability. This further improves battery capacity and discharge efficiency.

[0156] In some embodiments, combined with Figure 9 As shown, the negative electrode 21 includes a negative electrode active material layer 2112, the negative electrode active material layer 2112 includes a negative electrode active material, the negative electrode active material includes graphite, and c satisfies: 2 milliohms ≤ c ≤ 35 milliohms.

[0157] Graphite exhibits superior electrical conductivity compared to silicon-based materials. When graphite is included as the negative electrode active material, its high conductivity helps reduce the overall resistance of the negative electrode 21, thereby improving current transmission efficiency. By controlling the sheet resistance c of the negative electrode 21 within the aforementioned range, the current transmission impedance can be reduced, improving the current transmission capability of the negative electrode 21 and preventing further impact on the battery's high-rate discharge capability.

[0158] In some embodiments, the particle size D50 of graphite ranges from 5 μm to 15 μm.

[0159] By controlling the particle size of the negative electrode graphite, the conductivity of the negative electrode sheet can be improved, thus avoiding affecting the high-rate discharge capability of the battery.

[0160] In other embodiments, combined with Figure 9 As shown, the negative electrode 21 includes a negative electrode active material layer 2112, the negative electrode active material layer 2112 includes a negative electrode active material, the negative electrode active material includes silicon-based material, and c satisfies: 1.5 milliohms ≤ c ≤ 30 milliohms.

[0161] Silicon-based materials can be silicon-carbon, silicon suboxide, etc.

[0162] When the negative electrode active material includes silicon-based materials, the high capacity characteristics of silicon-based materials can significantly improve the energy density of the battery, but the kinetic performance of silicon-based materials is poor. By controlling the sheet resistance c of the negative electrode 21 within the above range, the conductivity and capacity advantages of silicon-based materials can be balanced, the overall resistance can be reduced, and the current transmission efficiency can be ensured, thereby avoiding affecting the high-rate discharge capability of the battery and improving the high-rate discharge capability of silicon-based materials.

[0163] In some embodiments, the silicon content in the negative electrode active material layer ranges from 0.5% to 20%.

[0164] In some embodiments, the compaction density of the negative electrode 21 ranges from 1.35 g / cm3 to 1.8 g / cm3; the porosity of the negative electrode 21 ranges from 15% to 40%.

[0165] By controlling the compaction density and, or, the porosity of the negative electrode sheet, the electrical contact between particles in the negative electrode sheet is improved, the conductivity of the negative electrode sheet is improved, and the high-rate discharge performance of the battery is enhanced.

[0166] In some embodiments, a satisfies: a≥99.5%; in this case, c satisfies: 1.5 milliohms≤c≤36 milliohms.

[0167] When the content a of Ti element in the shell 1 reaches a certain proportion, for example, a=99.5%, the shell 1 is a pure titanium shell, which can achieve lightweighting well, but it will cause the conductivity of the shell 1 to be worse. At this time, by controlling the surface resistance c of the negative electrode 21 within the above range, the conductivity of the battery can be further optimized, and the battery can achieve better high-rate discharge capability.

[0168] In some embodiments, a satisfies: a < 99.5%; in this case, c satisfies: 2 milliohms ≤ c ≤ 40 milliohms.

[0169] When the content a of Ti element in the shell 1 reaches a certain proportion, it can achieve lightweighting. However, as the content a of Ti element in the shell 1 increases, the conductivity of the shell 1 will be worse. By controlling the titanium content, the impact on the conductivity of the shell can be reduced. At the same time, by controlling the surface resistance c of the negative electrode 21 within the above range, the conductivity of the battery can be further optimized, and the battery can achieve better high-rate discharge capability.

[0170] In some embodiments, combined with Figure 6 As shown, the housing 1 includes a housing body 11 and a cover plate 12. At least one end of the housing body 11 is provided with an opening, and the cover plate 12 is fastened to the opening. The negative electrode tab of the battery cell 2 is electrically connected to the cover plate 12.

[0171] In some other embodiments, the housing 1 includes a housing body 11 and a cover plate 12. At least one end of the housing body 11 is provided with an opening, the cover plate 12 is fastened to the opening, and the electrode tab of the battery cell 2 is electrically connected to the housing body 11.

[0172] The negative electrode tab of the battery cell 2 is electrically connected to the housing body 11, and the housing body 11 serves as one of the electrode output electrodes.

[0173] In some embodiments, a satisfies: 90% ≤ a ≤ 99.99%;

[0174] And / or, b satisfies: 0.3mm ≤ b ≤ 1.5mm;

[0175] And / or, c satisfies: 1 milliohm ≤ c ≤ 50 milliohm.

[0176] When the Ti content 'a' within the casing 1 is within the aforementioned range, the conductivity of the casing 1 is effectively balanced. This maintains the advantages of lightweight design, improves the battery's energy density, and helps increase flight speed. Simultaneously, it avoids excessive degradation of conductivity, thus ensuring stable and efficient battery operation even during high-rate charging and discharging.

[0177] When the wall thickness b of the casing 1 is within the above range, the current transmission path can be improved, the battery impedance can be reduced, and the battery's high-rate charging capability can be achieved. Furthermore, the overall strength and heat dissipation performance of the casing 1 are optimized, further enhancing the battery's safety and lifespan.

[0178] When the sheet resistance c of the negative electrode 21 is within the above range, the internal resistance of the battery is within a reasonable range, ensuring the lithium-ion transport capability and electron transport capability, reducing battery impedance, making the current distribution more uniform, reducing the risk of local overheating, improving the overall charging and discharging efficiency, and ensuring the stability and reliability of the battery under high load conditions.

[0179] By precisely controlling parameters a, b, and c, a combination of lightweight design and high performance is achieved, meeting the stringent requirements of high-end application scenarios for battery performance.

[0180] For example, in this embodiment, the value of 'a' can be 90%, 93%, 95%, 98%, or 99.99%, or it can be any range formed by any two of the above values.

[0181] For example, in this embodiment, the value of b can be 0.3mm, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, or 1.5mm, or it can be any range formed by any two of the above values.

[0182] For example, in this embodiment, the value of c can be 1 milliohm, 3 milliohm, 5 milliohm, 10 milliohm, 18 milliohm, 25 milliohm, 29 milliohm, 32 milliohm, 41 milliohm, or 50 milliohm, or it can be any range formed by any two of the above values.

[0183] According to an embodiment of the present invention, another aspect provides a battery pack, including a battery housing and a battery as described above disposed within the battery housing.

[0184] According to an embodiment of the present invention, in another aspect, an electrical device is also provided, including an electrical device body and a battery pack as described above disposed on the electrical device body.

[0185] Electrical equipment can be low-altitude aircraft, such as flying cars, which can fly at low altitudes to increase travel speed, or other conventional vehicles.

[0186] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope defined by the present invention.

Claims

1. A battery, characterized by, The shell (1) comprises a Ti element, the mass element ratio of the Ti element in the shell (1) is a; a is greater than or equal to 90%, the wall thickness of the shell (1) is b; unit: mm; the surface resistance of the negative pole piece (21) is c, unit: milliohm; and 96<=a*b*c<=7570 is met. The electric core (2) is a four-prism electric core, the electric core (2) comprises an electric core body (20), and the negative pole lug (212) extends out from the first end face (201) of the electric core body (20) along a first direction; the negative pole lug (212) is arranged at the center position of the first end face (201) along a second direction; wherein the second direction is perpendicular to the first direction; The distance between the two ends of the negative pole lug (212) along the second direction and the two end faces of the electric core body (20) along the second direction is d1 and d2 respectively, and d1=d2 is met; at this time, c meets 2 milliohm<=c<=40 milliohm. The electric core (2) comprises an electric core body (20), and the negative pole lug (212) extends out from the first end face (201) of the electric core body (20) along a first direction; 2. The battery of claim 1, wherein, The distance between the two ends of the negative pole lug (212) along the second direction and the two end faces of the electric core body (20) along the second direction is d1 and d2 respectively; wherein the second direction is perpendicular to the first direction; The size of the first end face (201) along the second direction is e, and 0.6<=(d1+d2) / e<=0.9 is met.

3. The battery of claim 2, wherein, The electric core (2) comprises an electric core body (20), and the negative pole lug (212) extends out from the first end face (201) of the electric core body (20) along a first direction; The distance between the two ends of the negative pole lug (212) along the second direction and the two end faces of the electric core body (20) along the second direction is not equal; wherein the second direction is perpendicular to the first direction; at this time, c meets 1 milliohm<=c<=35 milliohm. The distance between the two ends of the negative pole lug (212) along the second direction and the two end faces of the electric core body (20) along the second direction is d1 and d2 respectively, and 0.5<=d1 / d2<1 or 1 4. The battery of claim 1, wherein, The electric core (2) comprises an electric core body (20), and the negative pole lug (212) extends out from the first end face (201) of the electric core body (20) along a first direction; The size of the first end face (201) along the second direction is e, and f 5. The battery of claim 4, wherein, ​ 6. The battery of claim 1, wherein, ​ ​ 7. The battery of claim 1, wherein, The electric core (2) comprises an electric core body (20), and the negative electrode tab (212) extends out from a first end surface (201) of the electric core body (20) in a first direction; The negative electrode tab (212) has a size f in a second direction, and the first end surface (201) has a size e in the second direction, and f = e is satisfied; at this time, the c satisfies 2.5 milliohms ≤ c ≤ 35 milliohms.

8. The battery of claim 1, wherein, The electric core (2) is a cylindrical electric core, the electric core (2) comprises an electric core body (20), and the electric core body (20) extends out a positive electrode tab (222) and the negative electrode tab (212); the positive electrode tab (222) and the negative electrode tab (212) are located on the same side of the electric core body (20) in the first direction, and at this time, the c satisfies 1.5 milliohms ≤ c ≤ 32 milliohms.

9. The battery of claim 1, wherein, The electric core (2) comprises an electric core body (20), and the electric core body (20) extends out a positive electrode tab (222) and the negative electrode tab (212); the positive electrode tab (222) and the negative electrode tab (212) are located on two sides of the electric core body (20) in the first direction, and at this time, the c satisfies 2 milliohms ≤ c ≤ 35 milliohms.

10. The battery of claim 8, wherein, The diameter of the electric core (2) is g, and g ≤ 50 mm is satisfied; at this time, the c satisfies 1.5 milliohms ≤ c ≤ 27 milliohms.

11. The battery of claim 8, wherein, The electric core (2) comprises multiple layers of the negative electrode sheet (21), each layer of the negative electrode sheet (21) comprises multiple sub-tabs (2120) distributed in a circumferential direction; in the same layer of the negative electrode sheet (21), there is a gap between adjacent sub-tabs (2120), and the c satisfies 1.5 milliohms ≤ c ≤ 25 milliohms.

12. The battery of claim 11, wherein, The size of a single sub-tab (2120) in the circumferential direction is m, and 2 mm ≤ m ≤ 8 mm is satisfied.

13. The battery of claim 8, wherein, The electric core (2) comprises multiple layers of the negative electrode sheet (21), each layer of the negative electrode sheet (21) comprises multiple sub-tabs (2120) distributed in a circumferential direction; in the expanded state of the negative electrode sheet (21), multiple sub-tabs (2120) in the same layer form a tab group (214), and in the length direction of the expanded negative electrode sheet (21), the negative electrode sheet (21) comprises a tab-free area (213), the tab-free area (213) is formed in a region of the negative electrode sheet (21) where the tab group (214) is not arranged, and the c satisfies 1 milliohms ≤ c ≤ 28 milliohms.

14. The battery of claim 13, wherein, The total length of the tab-free area (213) is h, and h = h1 + h2 + … + hn is satisfied, where hn is the length of a section of the tab-free area (213), and n is the number of the tab-free areas (213); the length of the negative electrode sheet (21) in the expanded state is j, and 0.05 ≤ h / j ≤ 0.2 is satisfied.

15. The battery of claim 1, wherein, The tab of the electric core (2) comprises a copper element, and the content of the copper element accounts for more than or equal to 99% of the total amount of elements in the tab.

16. The battery of claim 1, wherein, The battery comprises a current collecting disc for electrically connecting the negative tab (212) and the shell (1), the current collecting disc comprises copper elements, and the content of the copper elements accounts for greater than or equal to 99% of the total content of elements in the current collecting disc.

17. The battery of claim 16, wherein, The surface of the current collecting disc comprises copper oxide, and the thickness of the copper oxide ranges from 1 micrometer to 10 micrometers.

18. The battery of claim 1, wherein, The battery comprises a pole, and the battery cell (2) further comprises a positive tab, and the positive tab comprises a positive tab, which is electrically connected with the pole.

19. The battery of claim 1, wherein, The negative tab body (211) comprises a current collector layer (2111) and a negative active material layer (2112), the thickness of the current collector layer (2111) is k1, the thickness of the negative active material layer (2112) is k2, and k1 / k2≤0.03 is satisfied, and at this time, the c satisfies 1.5 milliohm≤c≤40 milliohm.

20. The battery of claim 19, wherein, The current collector layer (2111) comprises a polymer layer (21111) and a metal layer (21112), and the c satisfies 1.8 milliohm≤c≤30 milliohm.

21. The battery of claim 20, wherein, The thickness of the polymer layer (21111) is k11, the thickness of the current collector layer (2111) is k12, and 0.1≤k11 / k12≤0.8 is satisfied.

22. The battery of claim 1, wherein, The negative tab (21) comprises a negative active material layer (2112), the negative active material layer (2112) comprises a negative active material, the negative active material comprises graphite, and the c satisfies 2 milliohm≤c≤35 milliohm.

23. The battery of claim 22, wherein, The particle size D50 of the graphite ranges from 5 micrometers to 15 micrometers.

24. The battery of claim 1, wherein, The negative tab (21) comprises a negative active material layer (2112), the negative active material layer (2112) comprises a negative active material, the negative active material comprises a silicon-based material, and the c satisfies 1.5 milliohm≤c≤30 milliohm.

25. The battery of claim 24, wherein, The content of silicon elements in the negative active material layer ranges from 0.5% to 20%.

26. The battery of claim 1, wherein, The compaction density of the negative electrode sheet (21) is in the range of 1.35 g / cm 3 -1.8 g / cm 3 The porosity of the negative electrode sheet (21) is in the range of 15-40%.

27. The battery of claim 1, wherein, The a satisfies a≥99.5%, and at this time, the c satisfies 1.5 milliohm≤c≤36 milliohm.

28. The battery of claim 1, wherein, The a satisfies a<99.5%, and at this time, the c satisfies 2 milliohm≤c≤40 milliohm.

29. The battery of claim 1, wherein, The a satisfies 90%≤a≤99.99%. And / or, the b satisfies 0.3mm≤b≤1.5mm. And / or, the c satisfies 1 milliohm≤c≤50 milliohm.

30. A battery pack, characterized by The battery comprises a battery box body, and the battery as claimed in any one of claims 1 to 29 is arranged in the battery box body.

31. An electrical device, comprising: The battery pack comprises a power consumption device body, and the battery as claimed in claim 30 is arranged in the power consumption device body.

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