Battery and battery pack

Abstract

The application relates to the technical field of new energy, and discloses a battery and a battery pack, the battery comprising: a shell, the shell containing Ti elements, and the proportion of the mass of the Ti elements in the total mass of the shell being greater than or equal to 60%; a pole, arranged on the shell; a battery core, comprising a battery core body and a tab, the tab comprising a positive tab and a negative tab, one of the positive tab and the negative tab being electrically connected with the pole, and the other being electrically connected with the shell; the proportion of the mass of the Ti elements in the total mass of the shell being a, the electrical conductivity of the shell being b, and the size of the tab drawn from the battery core body being c; and 99 <= a * c / b <= 3650 is satisfied. The battery provided by the application controls the relationship among a, b and c, realizes the lightweight of the shell, meets the overcurrent capacity of the battery, avoids large temperature rise of the battery, and prevents the emergence of the poor safety performance of the battery.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a battery and battery pack. 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 charging and discharging capabilities. Summary of the Invention

[0003] In view of this, the present invention provides a battery to solve the problem of how to balance lightweight design and high-rate charging and discharging.

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

[0005] The shell contains Ti, and the mass of Ti accounts for more than or equal to 60% of the total mass of the shell.

[0006] The pole is located in the housing;

[0007] A battery cell includes a cell body and tabs. The tabs include a positive tab and a negative tab. One of the positive tabs and the negative tab is electrically connected to the terminal post, and the other is electrically connected to the casing.

[0008] The mass of Ti in the shell accounts for a percentage of the total mass of the shell; the conductivity of the shell is b, in S / m; the size of the tab leading out from the cell body is c; satisfying: 99≤a·c / b≤3650.

[0009] Beneficial Effects: The battery provided in the embodiments of the present invention has a casing containing Ti, which helps to achieve a lightweight casing. However, since the conductivity of the Ti-containing casing is relatively poor, and the casing also needs to serve as an electrical connection terminal, increasing the Ti content can negatively affect the battery's overcurrent. By comprehensively controlling the relationship between a, b, and c, the overcurrent capacity between the cell and the casing is improved, the high-rate charging capability is enhanced, and the charging time is shortened. In addition, the welding effect can be improved, and the welding yield can be increased. Furthermore, the casing can be made lighter. When the a·c / b formula value is too large, the current capacity between the cell and the casing is poor, the battery's overcurrent capacity is poor, the high-rate charging capability is poor, and the battery's charging time is affected. When the formula value is too small, the battery cannot achieve lightweighting, the battery's energy density is low, and the welding yield of the tabs is also affected.

[0010] In a second aspect, the present invention provides a battery pack, comprising:

[0011] Multiple batteries as described above;

[0012] Adjacent batteries are electrically connected via a conductive busbar, which is electrically connected to the battery casing. The conductive busbar and the casing are made of different materials, and the casing's conductivity b satisfies 1.6 × 10⁻⁶. 6 S / m≤b≤2.0×10 6 S / m.

[0013] Beneficial effects: The conductive busbar is electrically connected to the battery casing to connect multiple batteries together. The conductive busbar is made of a different material than the casing. By controlling the conductivity of the casing within the above-mentioned range, it is possible to avoid affecting the current transmission between the battery and the conductive busbar. Attached Figure Description

[0014] 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.

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

[0016] Figure 2 This is a schematic diagram of a battery cell when the positive and negative electrode tabs of the present invention are arranged on the same side;

[0017] Figure 3 This is a schematic diagram of the solder marks on the positive and negative electrode tabs of the present invention;

[0018] Figure 4 This is a schematic diagram of the electrode sheet in the unfolded state of the present invention;

[0019] Figure 5 This is a schematic diagram of one side when the positive and negative electrode tabs of the present invention are located on opposite sides;

[0020] Figure 6 This is a schematic diagram of another electrode unfolding state according to the present invention;

[0021] Figure 7 This is a cross-sectional view of the battery cell of the present invention.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Shell; 11. Shell body; 12. Cover plate;

[0024] 2. Battery cell; 21. Positive tab covered area; 22. Negative tab covered area; 23. Battery cell body; 24. Tab; 241. Positive tab; 242. Negative tab; 25. Core hole; 200. Electrode sheet; 201. Tab assembly;

[0025] 3. Pole post; 5. Solder mark. Detailed Implementation

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Metallic titanium (Ti) has a significantly lower density than steel, and its specific strength (strength / density) is extremely high. Therefore, Ti components can be lighter than steel components while meeting the same strength requirements. Thus, adding a certain proportion of Ti to the casing can reduce its weight and achieve lightweighting. However, increasing the Ti content results in relatively poor conductivity of the casing, leading to poor current flow between the tabs and the casing, which affects the battery's high-rate discharge capability. For flying cars, a balance between lightweighting and high-rate charge / discharge capabilities is necessary. Therefore, how to reduce casing weight, achieve lightweighting, and simultaneously support high-rate charge / discharge has become a pressing issue.

[0032] According to an embodiment of the present invention, a battery is provided, which will first be described as follows:

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The positive electrode, negative electrode, electrolyte, and separator are described in turn below:

[0037] [Positive electrode tablets]

[0038] 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.

[0039] 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).

[0040] 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.

[0041] 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.

[0042] 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.

[0043] [Negative electrode plate]

[0044] 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.

[0045] 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.

[0046] 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).

[0047] 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.

[0048] Electrolyte

[0049] 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.

[0050] 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.

[0051] 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).

[0052] 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).

[0053] [Septum]

[0054] 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.

[0055] 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.

[0056] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.

[0057] The battery provided in the embodiments of the present invention includes:

[0058] Shell 1 contains Ti element, and the mass of Ti element accounts for more than or equal to 60% of the total mass of shell 1;

[0059] The pole post 3 is disposed on the housing 1;

[0060] The battery cell 2 includes a battery cell body 23 and a tab 24. The tab 24 includes a positive tab 241 and a negative tab 242. One of the positive tab 241 and the negative tab 242 is electrically connected to the terminal 3, and the other is electrically connected to the housing 1.

[0061] The mass of Ti element in shell 1 accounts for a percentage of the total mass of shell 1; the electrical conductivity of shell 1 is b, in S / m; the size of tab 24 extending from the cell body 23 is c; satisfying: 99≤a·c / b≤3650.

[0062] One of the positive electrode tab 241 and the negative electrode tab 242 is electrically connected to the terminal post 3, and the other is electrically connected to the housing 1. For example, the positive electrode tab 241 can be electrically connected to the terminal post 3, and the negative electrode tab 242 can be electrically connected to the housing 1; alternatively, the negative electrode tab 242 can be electrically connected to the terminal post 3, and the positive electrode tab 241 can be electrically connected to the housing 1. Furthermore, the tab 24 can be directly connected to the terminal post 3 and the housing 1, or it can be connected through a current collector.

[0063] The mass percentage of Ti in shell 1 relative to the total mass of shell 1 is denoted as 'a'. In this embodiment, the method for determining the mass percentage of Ti in shell 1 relative to the total mass of shell 1 can be X-ray fluorescence spectrometry, as detailed below:

[0064] (1) Sample preparation: First, the shell 1 sample needs to be properly treated to allow X-rays to penetrate and excite fluorescence. This may include steps such as cutting, grinding, and polishing to ensure that the sample surface is flat and free of contamination.

[0065] (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.

[0066] (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.

[0067] (4) Matrix effect correction: Due to the interaction between various elements in the shell (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.

[0068] (5) Interpretation of results: Based on the corrected data, the content of each element in shell 1 can be calculated, and then the mass of Ti element in shell 1 can be determined as a percentage of the total mass of shell 1.

[0069] The electrical conductivity of shell 1 is b. In this embodiment, the electrical conductivity of shell 1 is measured according to the national standard GB / T35392-2017, using an electromagnetic (eddy current) method. The electrical conductivity of the shell can be adjusted by selecting titanium with different crystal structures, controlling oxygen content, and other factors.

[0070] 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.

[0071] In this embodiment, the battery can specifically be a cylindrical battery made in a wound form. The battery cell 2 includes a cell body 23 and tabs 24. The tabs 24 can be partially extended from the electrode sheet 200. For example, the tabs 24 can be the current collector of the electrode sheet 200. As a key component of the battery, the tabs 24 are used to transmit the internal current of the cell and lead out the internal current of the cell. The material of the tabs 24 can be the same as that of the current collector. For example, the tabs can be made of at least one of aluminum with silver plating, stainless steel with silver plating, stainless steel, copper, aluminum, nickel, carbon, nickel, or titanium. Furthermore, the tabs 24 can be cut from the current collector or can be a separately formed metal part. It is understood that the positive tab is electrically connected to the positive electrode sheet in the cell body 23, and the negative tab is electrically connected to the negative electrode sheet in the cell body 23. The electrode sheet 200 can include a positive electrode sheet and a negative electrode sheet. The positive electrode sheet, the separator, and the negative electrode sheet are stacked and wound to form the cell body 23. At this time, the tabs 24 extend axially relative to the cell body 23.

[0072] Combination Figure 4 As shown, the dimension c of the tab 24 extending from the cell body 23 refers to the straight-line distance from the root of the electrode plate 200 to the end of the tab 24 away from the electrode plate 200 when the cell 2 is in the unfolded state.

[0073] In this embodiment, the terminal post 3 is disposed on the housing 1, which includes a housing body 11. The terminal post 3 is disposed on one of the walls of the housing body 11. As a variation, the housing 1 includes the housing body 11 and a cover plate 12. An opening is formed on the housing body 11, and the cover plate 12 is placed over the opening of the housing body 11 and fixed by a sealing structure to ensure the stability and safety of the internal environment of the battery. The terminal post 3 is disposed on the cover plate 12 and is insulated from the housing body 11.

[0074] The battery provided in the embodiments of the present invention has a casing 1 containing Ti, which helps to achieve a lightweight casing 1. However, since the conductivity of the casing containing Ti is relatively poor, the casing 1 also needs to act as an electrical connection terminal to transmit the current inside the cell. As the Ti content increases, it will affect the battery overcurrent. If the current transmission between the cell and the casing is not smooth, it will cause the battery impedance to increase, affecting the high-rate charging performance of the battery, and thus affecting the battery charging efficiency. By comprehensively controlling the relationship between a, b, and c, the overcurrent capacity between the cell and the casing can be improved, the high-rate charging capacity can be improved, and the charging time can be shortened. In addition, the welding effect can be improved, and the welding yield can be increased. Furthermore, the casing can be made lighter. When the value of the a·c / b formula is too large, the current capacity between the cell and the casing is poor, the battery overcurrent capacity is poor, the high-rate charging capacity is poor, and the charging time of the battery is affected. When the formula value is too small, the battery cannot achieve lightweighting, the battery energy density is low, and the welding yield of the tabs will also be affected.

[0075] For example, in this embodiment, the value of a·c / b can be 99 or 175 or 230 or 460 or 500 or 593 or 742 or 1202 or 1531 or 2763 or 3650, or it can be any range formed by any two of the above values.

[0076] In some embodiments, a satisfies: 60% ≤ a ≤ 99.99%;

[0077] And / or, b satisfies: 1.5 × 10 6 S / m≤b≤2.0×10 6 S / m;

[0078] And / or, c satisfies: 3mm≤c≤50mm.

[0079] This embodiment controls the mass ratio 'a' of Ti in the casing 1 within the aforementioned range, thereby avoiding a decrease in the battery's overcurrent capacity due to an excessively high Ti mass ratio, preventing impact on the casing's current transmission capability, and avoiding an increase in battery impedance, thus preventing any impact on the battery's high-rate charging performance. Furthermore, it ensures the lightweight design of the casing 1, maintaining the battery's lightweight advantage.

[0080] This embodiment improves the battery's overcurrent capability by rationally selecting the casing 1 and constraining the conductivity b of the casing 1 within the above-mentioned range. This ensures that the casing 1 has good conductivity, resulting in low overcurrent resistance and better overcurrent capability when the tabs and casing are electrically connected. It also prevents insufficient overcurrent capability caused by low battery conductivity, avoids large temperature rise in the battery, and prevents poor battery safety performance.

[0081] The size of the tab 24 extending from the cell body 23 affects the current transmission path. A long current transmission path can easily increase the impedance during battery transmission, thus affecting the current transmission between the cell and the casing and impacting the battery's high-rate charging performance. In this embodiment, by controlling the size c of the tab 24 extending from the cell body 23 within the aforementioned range, the internal resistance of the tab 24 is avoided from increasing due to excessive length, thereby ensuring the battery's overcurrent capacity. This results in low overcurrent impedance and better overcurrent capacity when the tab and casing are electrically connected, improving current conduction efficiency. At the same time, it ensures that the tab 24 has sufficient welding area to avoid poor welding and further stabilizes the battery's performance.

[0082] For example, in this embodiment, the value of 'a' can be 60%, 72%, 78%, 82%, 89%, or 99.99%, or it can be any range formed by any two of the above values.

[0083] For example, in this embodiment, the value of b can be 1.5 × 10⁻⁶. 6 S / m or 1.7×10 6 S / m or 1.83×10 6 S / m or 1.9×10 6 S / m or 2.0×10 6 S / m, etc., can also be any range formed by any two of the above values.

[0084] For example, in this embodiment, the value of c can be 3mm or 8mm or 13mm or 23mm or 29mm or 34mm or 39mm or 42mm or 50mm, or it can be any range formed by any two of the above values.

[0085] Referring to Table 1 below, the provided battery was subjected to fast charging performance testing and welding yield testing through several embodiments and comparative tests to verify its qualification.

[0086] Table 1

[0087]

[0088] Regarding the table above, the following explanation is provided:

[0089] Performance 1: Fast Charging Performance Test. Test Method (taking a nickel-cobalt-manganese ternary cathode material as an example):

[0090] a. Charge the battery at a constant current of 0.33C to the upper limit voltage of 4.25V, then charge it at a constant voltage until the cutoff current is less than or equal to 0.05C, and then discharge it;

[0091] Repeat the above steps 3 times, and use the discharge capacity of the third discharge as the discharge capacity of the battery.

[0092] b: Based on the battery capacity in a, charge the battery at 0.33C to 10% SOC; denoted as T0;

[0093] c: Then, charge the battery at 4C, 3.5C, 3.0C, 2.75C, 2.5C, 2.25C, 2.0C, 1.75C, 1.5C, 1.25C, 1C, and 0.33C respectively to the cutoff voltages of 3.95V, 3.97V, 3.985V, 3.996V, 4.005V, 4.015V, 4.025V, 4.045V, 4.067V, 4.091V, 4.11V, and 4.25V. Record the time taken to charge the battery to 80% SOC as T1. T1-T0 is the fast charging time, in minutes.

[0094] The conclusions of the fast charging performance test in the table above include the following: Fast charging time is recorded in minutes; a fast charging time of 23 minutes or less is considered good; a fast charging time of 23 minutes or less than or equal to 28 minutes is considered acceptable; and a fast charging time of more than 28 minutes is considered unacceptable.

[0095] Performance 2: Welding Yield Test. The test method is as follows: After the tab (or current collector) is welded to the casing, a tensile testing machine is used to clamp the tab (or current collector) and the casing respectively, and a tensile test is performed perpendicularly. The force data when the tab is pulled off is recorded. If the pull-off force is greater than or equal to 10N, it proves that the weld is strong; if it is less than 10N, the weld is not strong. Twenty batteries are selected for testing in each group, and the yield is statistically analyzed.

[0096] In the table above, the conclusions of the welding yield test include the following: a welding yield of 95% or higher is considered good; a welding yield of 85% or higher but less than 95% is considered acceptable; and a welding yield of less than 85% is considered unacceptable.

[0097] The battery manufacturing process includes the following steps:

[0098] (1) Preparation of the positive electrode:

[0099] The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF were mixed, and solvent NMP was added. The mixture was stirred under vacuum until the system was homogeneous to obtain a positive electrode slurry. The positive electrode slurry was 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 was cold-pressed and slit to obtain the positive electrode sheet. Specifically, the mass ratio of positive electrode material: conductive agent: binder satisfies 96:2:2.

[0100] (2) Preparation of negative electrode:

[0101] 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, air-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 96:1.5:1.5:1.

[0102] (3) Preparation of electrolyte:

[0103] 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.

[0104] (4) Preparation of the diaphragm:

[0105] Polyethylene film is selected as the diaphragm.

[0106] (5) Preparation of lithium-ion batteries:

[0107] The positive electrode, separator, and negative electrode are prepared in sequence through a stacking process, with the separator positioned between the positive and negative electrodes to act as a separator. After the battery cell is prepared, it is installed in the casing, the battery cover is welded, and the battery undergoes processes such as electrolyte injection, formation, and capacity setting.

[0108] It should be noted that the embodiments listed above are only some possible implementations in the battery manufacturing process, and are not an exhaustive list of all implementations. Those skilled in the art will understand that battery manufacturing is not limited to the selection of positive and negative electrode materials, electrolyte formulation, separator selection, etc. listed above.

[0109] Regarding the test results, referring to Table 1 above, the explanation is as follows:

[0110] Based on Examples 1-21 and Comparative Examples 1 and 2, it can be seen that when the formula value satisfies 99-3650, the fast charging time of the battery is less than or equal to 28 minutes, and the welding yield is greater than or equal to 85%. From the test results of Performance 1 and 2, it can be seen that in Examples 1-21, the fast charging time is less than or equal to 28 minutes, and the welding yield is greater than or equal to 85%. In Comparative Example 1, the value of a·c / b is less than the lower limit of the formula value, and the welding yield is less than 85% after performance testing, which fails to meet the performance requirements. In Comparative Example 2, the value of a·c / b is greater than the upper limit of the formula value. After performance 1 test, the fast charging time is greater than 28 minutes, which fails to meet the performance requirements.

[0111] For cylindrical batteries, as shown in Examples 1-8, when the formula is within the range of 99-593, performance testing shows that the fast charging time is less than or equal to 23 minutes and the welding yield is greater than or equal to 95%. In Example 9, the formula range is 99-3650, but it does not meet the preferred range of 99-593 for cylindrical batteries, so the fast charging time is greater than 23 minutes. In Example 10, the parameter range of the lead-out dimensions does not meet the preferred range, resulting in a slightly lower welding yield than in Examples 1-9.

[0112] For prismatic batteries, as shown in Examples 11-19, when the formula range is 460-3650, the fast charging time is less than or equal to 23 minutes and the welding yield is greater than or equal to 95% after performance testing. As shown in Example 20, when the formula range does not meet the preferred range of 460-3650 for prismatic batteries, the welding yield is less than 95% but greater than or equal to 85%, which is worse than that of Examples 11-19. In Example 21, the lead-out size range is smaller than the preferred range, and the welding yield is worse than that of Examples 11-19.

[0113] In some embodiments, the area where the positive electrode tab 241 of the battery cell 2 is led out forms a positive electrode tab coverage area 21, and the area where the negative electrode tab 242 of the battery cell 2 is led out forms a negative electrode tab coverage area 22.

[0114] The positive electrode tab 241 or the negative electrode tab 242 is directly or indirectly welded to the shell 1, and the welding position forms a weld mark 5; the area of ​​the weld mark 5 is S1, the projected area of ​​the positive electrode tab covered area 21 on the end face of the positive electrode tab 241 leading out of the cell 2 is S2, and the projected area of ​​the negative electrode tab covered area 22 on the end face of the negative electrode tab 242 leading out of the cell 2 is S3, satisfying: 0.045≤S1 / S2≤0.052, or 0.045≤S1 / S3≤0.052.

[0115] It should be noted that the electrode tab can be directly welded to the housing 1, or it can be welded indirectly through the manifold to achieve electrical connection between the electrode tab and the housing. When the electrode tab is directly welded to the housing 1, the weld mark 5 formed at the welding position is specifically the weld mark of the welding area between the electrode tab and the housing 1. When the electrode tab is welded to the housing through the manifold, the weld mark 5 formed at the welding position is specifically the weld mark of the welding area between the electrode tab and the manifold.

[0116] The area S1 of the solder mark 5 affects the battery's overcurrent capacity. This area has a more significant impact on overcurrent. By controlling the area of ​​the solder mark 5, the effective overcurrent area between the cell and the casing can be ensured, thereby improving the overcurrent capacity and thus improving the battery's charging performance. By limiting the values ​​of S1 / S2 or S1 / S3 to the above range, on the one hand, the lead-out size can be appropriately shortened to reduce the overcurrent path, reduce the impedance during current transmission, and improve the current transmission efficiency, thereby improving the battery's rate charging performance. On the other hand, it can prevent insufficient welding strength caused by an excessively small solder mark area. When S1 / S2 or S1 / S3 is within a reasonable range, the overcurrent capacity of the battery at the position of the solder mark 5 is guaranteed. At this time, the size c of the tab 24 leading out from the cell body 23 can be appropriately shortened to further reduce internal resistance and improve current conduction efficiency.

[0117] Furthermore, by limiting the upper limits of S1 / S2 or S1 / S3, material waste caused by excessively large solder areas can be effectively prevented, while ensuring a reasonable distribution of welding strength and avoiding structural instability caused by excessively large solder areas. This optimizes material usage and improves overall manufacturing efficiency while ensuring battery overcurrent capacity and safety performance.

[0118] For example, in this embodiment, the value of S1 / S2 can be 0.045, 0.048, 0.05, 0.051, or 0.052, or it can be any range formed by the two values ​​mentioned above.

[0119] For example, in this embodiment, the value of S1 / S3 can be 0.045 or 0.048 or 0.05 or 0.051 or 0.052, or it can be any range formed by the two values ​​mentioned above.

[0120] In this embodiment, the value of S1 can be in the range of S1≥16mm. 2 The value of S2 can be in the range of 310mm. 2 ≤S2≤350mm 2 The value of S3 can be in the range of 310mm. 2 ≤S3≤350mm 2 .

[0121] In some embodiments, combined with Figure 7 As shown, the total thickness of the positive electrode tab 241, which is located in the positive electrode tab coverage area 21 and is electrically connected to the housing 1, is H1, satisfying: 0.1mm≤H1≤0.3mm; or, the total thickness of the negative electrode tab 242, which is located in the negative electrode tab coverage area 22 and is electrically connected to the housing 1, is H2, satisfying: 0.1mm≤H2≤0.4mm.

[0122] By controlling the thickness of H1 or H2 within the aforementioned range, the connection stability between the tab and the casing or between the tab and the current collector is ensured, resulting in good current transmission stability. This improves the current transmission capability between the tab and the casing, enhancing the battery's rate charging performance. Simultaneously, it avoids increased internal resistance and excessive welding heat due to excessive thickness, or insufficient connection strength due to insufficient thickness. This improves battery performance while ensuring its long-term reliability. Optimizing the battery's internal structure ensures efficient current conduction, further reducing energy loss.

[0123] In addition, by properly setting the thickness of H1 or H2, not only can the heat accumulation inside the battery be effectively reduced, but the overall heat dissipation performance can also be improved, ensuring the stability and safety of the battery under high load conditions, extending its service life, and enhancing the user experience.

[0124] When H1 or H2 is within a reasonable range, the overcurrent capacity of the battery at the position of tab 24 is guaranteed. At this time, the dimension c of tab 24 leading out from cell body 23 can be appropriately shortened to further reduce internal resistance and improve current conduction efficiency.

[0125] For example, in this embodiment, the value of H1 can be 0.1mm, 0.2mm, 0.23mm, 0.28mm, or 0.3mm, or it can be any range formed by any two of the above values.

[0126] For example, in this embodiment, the value of H2 can be 0.1mm or 0.2mm or 0.23mm or 0.28mm or 0.3mm or 0.35mm or 0.39mm or 0.4mm, or it can be a range formed by any two of the above values.

[0127] In some embodiments, cell 2 is a quadrangular prism cell that satisfies: 460≤a·c / b≤3650;

[0128] Alternatively, cell 2 can be a cylindrical wound cell, satisfying: 99≤a·c / b≤593.

[0129] In some embodiments, the battery cell 2 is a quadrangular prism battery cell, and the battery cell 2 includes multiple layers of electrode sheets, including positive electrode sheets and negative electrode sheets. Each layer of electrode sheets is provided with a single tab 24. The dimension c of the single tab 24 leading out from the battery cell body 23 satisfies: 20mm≤c≤50mm.

[0130] In some embodiments, in a direction that is perpendicular to both the lead-out direction of the tab 24 and the plane of the electrode, the size of a single tab 24 is smaller than the size of the electrode corresponding to the tab 24; c satisfies: 25mm≤c≤50mm.

[0131] In some other embodiments, in a direction that is perpendicular to both the lead-out direction of the tab 24 and the plane of the electrode, the size of a single tab 24 is equal to the size of the electrode corresponding to that tab 24; c satisfies: 20mm≤c≤45mm.

[0132] In some embodiments, the battery cell 2 is a cylindrical wound battery cell, the battery cell 2 forms a multi-layer structure in the radial direction, the battery cell 2 includes electrode sheets, the electrode sheets include multiple positive electrode sheets and multiple negative electrode sheets, and multiple tabs 24 are led out from the positive electrode sheets or negative electrode sheets.

[0133] Along the circumference of the cell 2, adjacent tabs 24 are spaced apart, and the dimension c of a single tab 24 extending from the cell body 23 satisfies: 3mm≤c≤8mm.

[0134] In some embodiments, along the circumferential direction of the cell 2, the size of the area where the tabs 24 are provided in the cell 2 is smaller than the circumferential size of the cell 2, and the size c of a single tab 24 extending from the cell body 23 satisfies: 4.5mm≤c≤8mm.

[0135] In some embodiments, a plurality of tabs 24 are continuously arranged around the circumference of the battery cell 2, and the dimension c of a single tab 24 extending from the battery cell body 23 satisfies: 3mm≤c≤7.5mm.

[0136] Since the positive electrode tab 241 and the negative electrode tab 242 are respectively located on opposite sides of the cell body 23, each layer of the wound cell includes multiple tabs 24 arranged circumferentially, and these multiple tabs 24 are continuously arranged around the circumference of the wound cell, thus forming a full tab structure. By controlling the dimension c of the tabs 24 extending from the cell body 23, excessive overlap of the tabs 24 is avoided, which would cause excessive thickness in the tab area, affecting welding and subsequent current flow. This ensures uniform current distribution and reduces the risk of local overheating.

[0137] In some embodiments, the width of a single tab 24 along the circumference of the cell 2 is E, satisfying 3mm≤E≤8mm.

[0138] Combination Figure 4 As shown, the width E of a single tab 24 specifically refers to the lateral distance occupied by the tab 24 on the unfolded plane when the cell is in the unfolded state.

[0139] Cylindrical cells include wound cells, which are formed by winding electrode sheets 200 and diaphragms, resulting in a multi-layered structure. Each layer of the wound cell includes multiple tabs 24 arranged circumferentially. By electrically connecting the tabs 24 to the electrode post 3 or the housing 1, effective current transmission is achieved.

[0140] In this embodiment, by ensuring that the value of E is within the above range, the continuity of the tab 24 overlap is achieved, thus guaranteeing the overcurrent capacity. At the same time, excessive overlap of the tab 24 is avoided, which would cause the tab area to become too thick locally, affecting the welding, which in turn affects the subsequent overcurrent and the rate charging performance of the battery.

[0141] When the circumferential width E of the tab 24 is within a reasonable range, the continuity of the tab 24 overlap can be achieved. This improves overcurrent while preventing excessive overlap of the tab 24, which could lead to excessive local thickness of the tab 24. In this case, the dimension c of the tab 24 leading out from the cell body 23 can be appropriately shortened to further reduce internal resistance and improve current conduction efficiency.

[0142] For example, in this embodiment, the value of E can be 3mm, 4mm, 5mm, 6mm, or 8mm, or it can be any range formed by any two of the above values.

[0143] In some embodiments, combined with Figure 2 As shown, the positive electrode tab 241 and the negative electrode tab 242 are located on the same side of the cell body 23, satisfying: 4.5mm≤c≤8mm.

[0144] The positive electrode tab 241 and the negative electrode tab 242 are led out from the same side of the cell body 23, avoiding the space occupation caused by tabs leading out from both sides, optimizing the internal layout of the battery, reducing space waste, and improving assembly efficiency. However, since the positive electrode tab 241 and the negative electrode tab 242 are located on the same side of the cell body 23, the area that can be set on the same end face of the positive electrode tab 241 and the negative electrode tab 242 is small, which can easily affect the current carrying capacity of the tabs. Therefore, it is necessary to further control the dimension c of the tab 24 leading out from the cell body 23 to ensure that the current carrying capacity is maximized within a limited area, while avoiding the current concentration phenomenon caused by the tab area being too small, avoiding the tab area affecting the overcurrent area, preventing the low overcurrent area between the casing and the cell, avoiding poor overcurrent transmission capacity, and avoiding affecting the rate charging capability.

[0145] In some embodiments, cell 2 is a cylindrical cell with a diameter D, satisfying: D≤60mm and satisfying: 4.8mm≤c≤8mm.

[0146] When cell 2 is a cylindrical cell, the area of ​​the end face of the cylindrical cell is generally small, resulting in a smaller area where the tabs 24 can be set. The arrangement of the tabs 24 is more compact, and the dimension c needs to be precisely controlled to ensure efficient current conduction within the limited end face area, prevent current concentration and local overheating caused by insufficient area of ​​the tabs 24, and thus ensure the stability and safety of the battery when it is at high power output.

[0147] For example, in this embodiment, the value of D can be 10mm or 20mm or 30mm or 40mm or 50mm or 60mm, or it can be a range formed by any two of the above values.

[0148] In some embodiments, the cell 2 is constructed as a multi-layer structure, with each layer of electrode having a tab 24, satisfying: 4mm≤c≤7mm.

[0149] Since the tab 24 needs to be folded onto the end face of the cell after it is led out from the cell body 23 for subsequent welding, when each layer of cell 2 has a tab 24, the folding of the tab 24 may cause the space on the end face of the cell to be crowded, increasing the difficulty of folding and thus easily affecting the welding quality.

[0150] Therefore, when each electrode layer has tabs 24, although the continuity of the tab 24 overlap can be achieved, the folding angle and sequence of the tabs 24 need to be precisely controlled to optimize the utilization of end-face space, ensure welding quality, and avoid uneven total tab thickness along the cell axis due to poor folding, resulting in low welding yield and uneven current transmission, thus affecting the rate charging performance. At this time, the dimension c of the tab 24 leading from the cell body 23 needs to be precisely controlled to further reduce internal resistance and improve current conduction efficiency. Simultaneously, by optimizing the dimension c of the tab 24 leading from the cell body 23, localized excessive thickness of the tabs 24 can be avoided, ensuring uniform thickness of each layer of tabs 24, reducing uneven current distribution caused by uneven thickness, and further improving the overall performance and safety of the battery.

[0151] In some other embodiments, the cell 2 is constructed as a multi-layer structure, with some layers having tabs 24 leading out from the electrode sheets, satisfying: 4.5mm≤c≤8mm.

[0152] Since the tab 24 needs to be folded onto the end face of the cell after being led out from the cell body 23 for subsequent welding, when tab 24 is led out from each layer of electrode sheets, the folding of tab 24 may cause congestion on the end face of the cell, increasing the difficulty of folding and thus easily affecting the welding quality. Conversely, leading out tab 24 from only some layers can alleviate the problem of congestion on the end face to a certain extent, reduce the difficulty of folding, and improve the welding quality. However, if tab 24 is led out from only some layers of electrode sheets, it may cause discontinuous overlap of tab 24, affecting the current carrying capacity. Therefore, based on leading out tab 24 from only some layers, it is necessary to optimize the dimension c of tab 24 leading out from the cell body 23 to ensure the continuity of tab 24 overlap, further improve the current carrying capacity, and ensure its high-rate charging performance.

[0153] In some embodiments, combined with Figure 3As shown, the battery cell 2 is a cylindrical wound battery cell. The battery cell 2 includes a winding hole 25, a positive electrode tab 241 or a negative electrode tab 242 which is welded to the housing 1, and the welding position forms a solder mark 5.

[0154] The radial distance between the centroids of the solder mark 5 and the core hole 25 is F, which satisfies: 7mm≤F≤10mm.

[0155] The centroid of the core hole 25 refers to the center of its geometric shape. By controlling the upper limit of the radial distance F between the centroids of the solder mark 5 and the core hole 25, insufficient welding area caused by excessive distance between them is avoided. Simultaneously, by controlling the lower limit of the radial distance F between the centroids of the solder mark 5 and the core hole 25, excessive distance between them is avoided. Excessive welding heat concentration due to close welding distance can easily cause deformation of the core hole 25 during welding, affecting the stability of the cell structure and hindering subsequent heat dissipation through the core hole 25.

[0156] For example, in this embodiment, the value of F can be 7mm, 8mm, 9mm, or 10mm, or it can be any range formed by any two of the above values.

[0157] In some other embodiments, the battery cell 2 is a cylindrical wound battery cell, with the positive electrode tab 241 and the negative electrode tab 242 respectively disposed on opposite sides of the battery cell body 23, satisfying: 3mm≤c≤7.5mm.

[0158] As a modified implementation, the positive electrode tab 241 and the negative electrode tab 242 are respectively located on opposite sides of the cell body 23. This avoids spatial conflicts caused by the positive electrode tab 241 and the negative electrode tab 242 being led out from the same end face, ensuring the arrangement area of ​​the positive electrode tab 241 and the negative electrode tab 242, and thus easily ensuring the current carrying capacity of the positive electrode tab 241 and the negative electrode tab 242. However, this arrangement may lead to a longer current path in the casing. For example, if the conductor busbars are all connected on the positive electrode tab side, then after the negative electrode tab is electrically connected to the casing, the current transmission must pass through the casing to reach the casing side corresponding to the positive electrode tab. In addition, this arrangement will also cause a deterioration in the current path. By controlling the dimension c of the tab 24 leading out from the cell body 23, the current carrying capacity requirements can be met, avoiding the increase in internal resistance caused by the tab 24 being too long, thereby ensuring the battery's current carrying capacity. At the same time, optimizing the dimension c can also effectively reduce the mutual interference between the tabs 24 and improve the compactness of the overall cell structure.

[0159] In some embodiments, cell 2 is a cylindrical cell with a diameter D, satisfying: D≤60mm and satisfying: 3.3mm≤c≤7mm.

[0160] In some embodiments, the battery cell 2 is a cylindrical wound battery cell, with positive electrode tab 241 and negative electrode tab 242 respectively disposed on opposite sides of the battery cell body 23 along the first direction, and the height of the housing 1 along the first direction is G, satisfying: 70mm≤G≤130mm.

[0161] Since the positive electrode tab 241 and the negative electrode tab 242 are respectively located on opposite sides of the cell body 23 along the first direction, the current path of the tabs electrically connected to the casing is long, and the impedance increases. The height G of the casing 1 along the first direction needs to be controlled within a certain range to avoid the current path being too long and to prevent the battery's overcurrent capacity from deteriorating.

[0162] For example, in this embodiment, the value of G can be 70mm or 80mm or 90mm or 100mm or 130mm, or it can be a range formed by any two of the above values.

[0163] In some embodiments, cell 2 is a cylindrical wound cell, combined with Figure 6 As shown, the tab 24 is trapezoidal, satisfying: 4.5mm≤c≤7.5mm;

[0164] Alternatively, cell 2 can be a cylindrical wound cell, combined with... Figure 4 As shown, the tab 24 is rectangular and satisfies: 3.5mm≤c≤8mm.

[0165] When the tab 24 is trapezoidal, the circumferential gap between adjacent tabs is relatively small. After welding, the welding area is continuous, resulting in better current carrying capacity. By reasonably controlling the dimension c of the tab 24 leading out from the cell body 23, the internal resistance caused by the tab 24 being too long is avoided, thereby ensuring the battery's current carrying capacity. When the tab and the casing are electrically connected, the current resistance is low, the current carrying capacity is better, and the current conduction efficiency is improved.

[0166] When the tab 24 is rectangular, the gap between adjacent tabs in the circumferential direction is relatively large. After welding, the continuity of the welding area is poor. However, by precisely controlling the dimension c, it is still possible to ensure uniform current distribution, reduce local overheating, maintain good overcurrent performance, and improve the overall stability of the battery.

[0167] In some embodiments, the battery cell 2 is a cylindrical wound battery cell, and the material of the tab 24 electrically connected to the housing 1 is a different metal from the material of the housing 1, or the material of the current collector electrically connected to the housing 1 is a different metal from the material of the housing 1, satisfying: 4.2mm≤c≤8mm.

[0168] Since the material of the tab 24 and the housing 1 are dissimilar metals, the welding difficulty increases. By precisely controlling the dimension c, it is necessary to avoid the dimension c of the tab 24 leading from the cell body 23 being too short, which would result in a weak weld and affect battery performance; at the same time, it is necessary to avoid the dimension c being too long, which would increase the contact resistance, thus ensuring both a strong weld and the overcurrent capacity. Specifically, the material of the tab can be copper.

[0169] In this embodiment, the tab 24 can be directly welded to the housing 1 without a current collector in between. As a variation, the tab 24 can also be connected to the housing 1 via a current collector, with the current collector made of the same material as the tab 24, to ensure welding stability, reduce contact resistance, and improve current conduction efficiency.

[0170] In some embodiments, the negative electrode tab 242 is electrically connected to the housing 1, and the negative electrode tab 242 comprises Cu, satisfying: 3.8mm≤c≤7.8mm.

[0171] When the negative electrode tab 242 is made of copper, the welding of Ti and Cu is difficult because the shell contains Ti. It is necessary to precisely control the dimension c to ensure a strong weld. At the same time, further control of the range of dimension c can reduce the current path, improve the current carrying capacity, and avoid affecting the subsequent current carrying.

[0172] Since the casing 1 in this embodiment contains Ti and the negative electrode tab 242 contains Cu, the welding between Ti and Cu is quite difficult. To reduce the welding difficulty, an appropriate amount of Cu is added to the casing 1 to optimize the welding process, improve the welding strength, and ensure a more stable connection between the casing 1 and the negative electrode tab 242. Furthermore, because Cu has good conductivity, adding an appropriate amount of Cu can effectively reduce contact resistance, improve overall conductivity, ensure smooth current transmission, and further improve current conduction efficiency. By precisely controlling the Cu content, both the mechanical strength of the welding area and the contact resistance are guaranteed, minimizing current loss during transmission and significantly improving the overall performance and reliability of the battery.

[0173] In some embodiments, the battery cell 2 is a cylindrical wound battery cell, with the positive electrode tab 241 electrically connected to the electrode post 3 and the negative electrode tab 242 electrically connected to the housing 1; satisfying: 175≤a·c / b≤500.

[0174] In this embodiment, the positive electrode tab 241 can be made of aluminum, and the negative electrode tab 242 can be made of copper. Since copper has better conductivity than aluminum, using a copper negative electrode tab 242 to electrically connect to the housing 1 improves the tab's conductivity and enhances its current-carrying capacity. Correspondingly, while meeting the current-carrying requirements, a can be appropriately increased, the conductivity of the housing 1 can be appropriately decreased, and the lead-out dimension c of the tab 24 from the cell body 23 can be appropriately reduced.

[0175] In some embodiments, the wall surface where the housing 1 is electrically connected to the tab 24 is the first wall surface, and the wall thickness of the first wall surface is J, which satisfies: 0.5mm≤J≤1.5mm.

[0176] By precisely controlling the thickness J of the first wall surface, the mechanical strength of the casing 1 is ensured, while avoiding excessive thickness of the first wall surface which would lead to an extended current path, increased contact resistance, and reduced current transmission efficiency. Simultaneously, a suitable wall thickness J facilitates heat dissipation, reduces local temperature rise, further ensures stable battery operation under high loads, and extends battery life.

[0177] For example, in this embodiment, the value of J can be 0.5mm, 0.8mm, 0.9mm, 1mm, 1.2mm, or 1.5mm, or it can be any range formed by any two of the above values.

[0178] In some embodiments, the cell 2 is a cylindrical wound cell, and the battery also includes a current collector, which includes a positive current collector and a negative current collector. The positive current collector and the negative current collector are disposed on the same side of the cell body 23 along a first direction, and the positive current collector and the negative current collector are electrically connected to the positive electrode tab 241 and the negative electrode tab 242, respectively.

[0179] The current collector includes a positive current collector and a negative current collector, as well as insulating components. The positive and negative current collectors are installed together on the insulating components to achieve an integrated design, while ensuring insulation between the positive and negative poles.

[0180] The positive current collector and the negative current collector are electrically connected to the positive electrode tab 241 and the negative electrode tab 242, respectively. Specifically, in this embodiment, the side of the positive current collector facing away from the positive electrode tab 241 is suitable for electrical connection with the electrode post 3; the side of the negative current collector facing away from the negative electrode tab 242 is suitable for electrical connection with the housing 1.

[0181] In some embodiments, the battery cell 2 is a cylindrical wound battery cell, the Ti element content of the casing 1 is greater than or equal to 99%, and c satisfies: 4.5mm≤c≤8mm.

[0182] In some other embodiments, the cell 2 is a cylindrical wound cell, the Ti element content of the casing 1 is less than or equal to 90%, and c satisfies: 3.5mm≤c≤7.5mm.

[0183] On the other hand, the present invention provides a battery pack comprising:

[0184] Multiple batteries as described above;

[0185] Adjacent batteries are electrically connected via a conductive busbar, which is electrically connected to the battery casing 1. The conductive busbar is made of a different material than the casing 1, and the conductivity b of the casing 1 satisfies: 1.6 × 10⁻⁶. 6 S / m≤b≤2.0×106 S / m.

[0186] In this embodiment, the material of the conductive bus is different from that of the housing 1. The conductive bus can be made of aluminum, copper, or other materials. Since the conductive bus needs to be electrically connected to the housing to connect multiple batteries together, the conductive bus material is different from the housing material. By controlling the conductivity b of the housing 1 to meet the above-mentioned value range, the current transmission between the batteries and the conductive bus is avoided.

[0187] 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 application relates to a battery shell and a battery. The battery shell comprises a shell (1) containing Ti elements, and the mass percentage of the Ti elements in the total mass of the shell (1) is greater than or equal to 60%; A pole column (3) is arranged on the shell (1); An electric core (2) comprises an electric core body (23) and a tab (24), the tab (24) comprises a positive tab (241) and a negative tab (242), one of the positive tab (241) and the negative tab (242) is electrically connected with the pole column (3), and the other is electrically connected with the shell (1); The mass percentage of the Ti elements in the total mass of the shell (1) is a; the electric conductivity of the shell (1) is b, the unit is S / m; the size of the tab (24) drawn from the electric core body (23) is c; and 99<=a*c / b<=3650 is satisfied.

2. The battery of claim 1, wherein, The a satisfies 60%<=a<=99.99%; And / or, the b satisfies: 1.5 x 10 6 S / m ≤ b ≤ 2.0 x 10 6 S / m; And / or, the c satisfies 3mm<=c<=50mm.

3. The battery of claim 1, wherein, The area where the electric core (2) draws the positive tab (241) forms a positive tab covering area (21), and the area where the electric core (2) draws the negative tab (242) forms a negative tab covering area (22); The positive tab (241) or the negative tab (242) is directly or indirectly welded with the shell (1), and the welding position forms a welding mark (5); the area of the welding mark (5) is S1, the projection area of the positive tab covering area (21) on the end face of the electric core (2) where the positive tab (241) is drawn is S2, the projection area of the negative tab covering area (22) on the end face of the electric core (2) where the negative tab (242) is drawn is S3, and 0.045<=S1 / S2<=0.052 or 0.045<=S1 / S3<=0.052 is satisfied.

4. The battery of claim 3, wherein, The total thickness of the positive tab (241) located in the positive tab covering area (21) and electrically connected with the shell (1) is H1, and 0.1mm<=H1<=0.3mm is satisfied; or the total thickness of the negative tab (242) located in the negative tab covering area (22) and electrically connected with the shell (1) is H2, and 0.1mm<=H2<=0.4mm is satisfied.

5. The battery of claim 2, wherein, The electric core (2) is a quadrangular prism electric core, and 460<=a*c / b<=3650 is satisfied; Or, the electric core (2) is a cylindrical winding electric core, and 99<=a*c / b<=593 is satisfied.

6. The battery of claim 5, wherein, The electric core (2) is a quadrangular prism electric core, and the electric core (2) comprises a plurality of layers of pole pieces, the pole pieces comprise positive pole pieces and negative pole pieces, and each layer of the pole pieces is provided with a single tab (24); the size c of the single tab (24) drawn from the electric core body (23) satisfies 20mm<=c<=50mm.

7. The battery of claim 6, wherein, In the direction perpendicular to the drawing direction of the tab (24) and the plane where the pole piece is located, the size of the single tab (24) is smaller than the size of the pole piece corresponding to the tab (24); and the c satisfies 25mm<=c<=50mm.

8. The battery of claim 6, wherein, In a direction perpendicular to the lead-out direction of the tab (24) and the direction of the plane where the tab is located, the size of a single tab (24) is equal to the size of the corresponding tab of the tab (24); the c satisfies: 20mm≤c≤45mm.

9. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the electric core (2) forms a multi-layer structure along the radial direction, the electric core (2) includes a tab, the tab includes a plurality of positive tabs and a plurality of negative tabs, the positive tab or the negative tab leads out a plurality of tabs (24); Along the circumferential direction of the electric core (2), the adjacent tabs (24) are arranged at intervals, and the size c of a single tab (24) led out from the electric core body (23) satisfies: 3mm≤c≤8mm.

10. The battery of claim 9, wherein, Along the circumferential direction of the electric core (2), the size of the area where the electric core (2) is provided with the tab (24) is smaller than the size of the circumferential direction of the electric core (2), and the size c of a single tab (24) led out from the electric core body (23) satisfies: 4.5mm≤c≤8mm.

11. The battery of claim 9, wherein, Along the circumferential direction of the electric core (2), a plurality of tabs (24) are continuously arranged around the circumferential direction of the electric core (2), and the size c of a single tab (24) led out from the electric core body (23) satisfies: 3mm≤c≤7.5mm.

12. The battery of claim 9, wherein, Along the circumferential direction of the electric core (2), the width of a single tab (24) is E, which satisfies: 3mm≤E≤8mm.

13. The battery of claim 9, wherein, The positive tab (241) and the negative tab (242) are arranged on the same side of the electric core body (23), and satisfy: 4.5mm≤c≤8mm.

14. The battery of claim 9, wherein, Each layer of the tab leads out a tab (24), and satisfies: 4mm≤c≤7mm.

15. The battery of claim 9, wherein, Part of the layers of the tab lead out a tab (24), and satisfy: 4.5mm≤c≤8mm.

16. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the electric core (2) includes a winding core hole (25), the positive tab (241) or the negative tab (242) is welded to the shell (1), and a welding position forms a welding mark (5); The distance between the welding mark (5) and the center of the winding core hole (25) in the radial direction is F, which satisfies: 7mm≤F≤10mm.

17. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the positive tab (241) and the negative tab (242) are arranged on opposite sides of the electric core body (23) respectively, and satisfy: 3mm≤c≤7.5mm.

18. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the positive tab (241) and the negative tab (242) are arranged on opposite sides of the electric core body (23) in a first direction respectively, the height of the shell (1) in the first direction is G, and satisfy: 70mm≤G≤130mm.

19. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the tab (24) is a trapezoid, and satisfy: 4.5mm≤c≤7.5mm; Or, the tab (24) is a rectangle, and satisfy: 3.5mm≤c≤8mm.

20. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, and the material of the tab (24) electrically connected with the shell (1) is different from the material of the shell (1), or the material of the current collecting plate electrically connected with the shell (1) is different from the material of the shell (1), and 4.2mm≤c≤8mm is satisfied.

21. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the positive electrode tab (241) is electrically connected with the pole (3), and the negative electrode tab (242) is electrically connected with the shell (1); 175≤a·c / b≤500 is satisfied.

22. The battery of claim 1, wherein, The wall surface of the shell (1) electrically connected with the tab (24) is a first wall surface, the wall thickness of the first wall surface is J, and 0.5mm≤J≤1.5mm is satisfied.

23. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, and the battery further comprises a current collecting plate, the current collecting plate comprises a positive electrode current collecting plate and a negative electrode current collecting plate, the positive electrode current collecting plate and the negative electrode current collecting plate are arranged on the same side of the electric core body (23) along a first direction, and the positive electrode current collecting plate and the negative electrode current collecting plate are respectively electrically connected with the positive electrode tab (241) and the negative electrode tab (242).

24. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the Ti element content of the shell (1) is greater than or equal to 99%, and the c satisfies 4.5mm≤c≤8mm.

25. The battery of claim 5, wherein, The electric core (2) is a cylindrical winding electric core, the Ti element content of the shell (1) is less than or equal to 90%, and the c satisfies 3.5mm≤c≤7.5mm.

26. A battery pack, comprising: Comprise: A plurality of batteries as claimed in any one of claims 1 to 25 above; The adjacent batteries are electrically connected through a conductive row, the conductive row is electrically connected with the shell (1) of the battery, the material of the conductive row is different from the material of the shell (1), and the electrical conductivity b of the shell (1) satisfies: 1.6*10 6 S / m≤b≤2.0*10 6 S / m.

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