Battery cell, battery device, energy storage device, energy storage system and power-consuming device

Abstract

A battery cell comprising a housing and an electrode assembly, wherein the electrode assembly comprises a cathode foil, an anode foil, a separator, and an electrolyte solution; wherein a width B, a height H, and a thickness T of the battery cell satisfy 350 mm ≤ B ≤ 650 mm, 170 mm ≤ H ≤ 300 mm, and 50 mm ≤ T ≤ 90 mm; wherein the anode foil comprises a collector and an anode material layer provided on at least one side of the collector, wherein, when the battery cell is in a fully charged state, a heat dissipation Q of the anode material layer in the electrolyte solution in which it is immersed satisfies the following: 180 J / g ≤ Q ≤ 600 J / g; wherein the fully charged state means that the state of charge of the battery cell is 100%.

Description

TECHNICAL AREA

[0001] The present application relates to the technical field of batteries, in particular a battery cell, a battery, an energy storage device, an energy storage system and a power-consuming device. STATE OF THE ART

[0002] The energy storage battery is a core component of the energy storage system, which primarily utilizes chemical reactions for energy storage. Energy storage requires a battery structure with high capacity, long cycle life, high safety, and high energy efficiency. However, high-capacity energy storage batteries generate large amounts of heat and dissipate it poorly, and this continuous heat generation poses safety risks such as fire and explosion. CONTENT OF THE PRESENT INVENTION

[0003] A first aspect of the present application provides a battery cell comprising a housing and an electrode arrangement, wherein the electrode arrangement comprises a cathode foil, an anode foil, a separator, and an electrolyte solution; wherein a width B, a height H, and a thickness T of the battery cell satisfy 350 mm ≤ B ≤ 650 mm, 170 mm ≤ H ≤ 300 mm, and 50 mm ≤ T ≤ 90 mm; wherein the anode foil comprises a collector and an anode material layer provided on at least one side of the collector, wherein, when the battery cell is in a fully charged state, a heat dissipation Q of the anode material layer in the electrolyte solution in which it is immersed satisfies the following: 180 J / g ≤ Q ≤ 600 J / g; wherein the fully charged state means that the state of charge of the battery cell is 100%.

[0004] In some embodiments, a first anode material layer comprises a first active anode material in a granular form, wherein a second anode material layer comprises a second active anode material in a granular form, wherein the particle size of the active anode material is Dv50; wherein Dv50 of the first active anode material and of the second active anode material is each independently 9 µm to 20 µm, optionally 10 µm to 15 µm.

[0005] In some embodiments, the first and second anode material layers each comprise a first active anode material and a second active anode material in granular form, wherein the specific surface area BET of the first active anode material and of the second active anode material is 1.3 m². 2 / g up to 3 m 2 / g.

[0006] In some embodiments, the anode material layer comprises a first anode material layer and a second anode material layer, wherein the second anode material layer is provided on a side of the first anode material layer facing away from the collector, wherein a ratio of a thickness t2 of the second anode material layer to a thickness t1 of the first anode material layer is satisfied to be 2 / 3≤t2 / t1≤1.5; and / or wherein the porosity of the second anode material layer is greater than the porosity of the first anode material layer.

[0007] In some embodiments, the thickness t1 of the first anode material layer and the thickness t2 of the second anode material layer are each independently selected from 57 µm to 87 µm; and / or wherein the porosity of the first anode material layer and the porosity of the second anode material layer are each independently selected from 25% to 36%.

[0008] In some embodiments, the electrolyte solution contains vinyl carbonate (EC), wherein the mass fraction of the vinyl carbonate in the electrolyte solution is 15 to 25%.

[0009] In some embodiments, the electrolyte solution contains propylene carbonate (PC), wherein the mass fraction of the propylene carbonate in the electrolyte solution is 1 to 8%.

[0010] In some embodiments, the housing comprises a housing body, wherein an inner surface and / or an outer surface of the housing body comprises a coating layer, the coating layer having a thermally conductive function; in some embodiments, the coating layer further has a heat-resistant function; in some embodiments, the total thickness of the coating layer is 1 µm to 12 µm; in some embodiments, the coating layer comprises one or more of the following substances: AlN, BeO, SiC, boron nitride; in some embodiments, the coating layer further comprises one or more of the following substances: Si3N4, aluminum trioxide, boehmite, zirconium oxide, titanium oxide.

[0011] In some embodiments, the battery cell capacity is greater than or equal to 500Ah.

[0012] In some embodiments, the cathode foil comprises a cathode material layer, wherein the cathode material layer comprises an active cathode material, the active cathode material comprising a lithium-containing phosphate. In some embodiments, the lithium-containing phosphate optionally comprises lithium iron phosphate.

[0013] In some embodiments, the charging voltage of the battery cell is 3.65 V.

[0014] In some embodiments, the immersion electrolyte solution comprises vinyl carbonate and methyl ethyl carbonate in a volume ratio of 3:7 and LiPF6 at a concentration of 1 mol / L.

[0015] A second embodiment of the present application provides a battery device comprising several battery cells according to the first embodiment of the present application.

[0016] A third embodiment of the present application provides an energy storage device comprising several battery cells according to the first embodiment of the present application or several battery devices according to the second embodiment of the present application, wherein the battery cells or the battery devices are used for storing or providing electrical energy.

[0017] A fourth embodiment of the present application provides an energy storage system comprising a power conversion device and an energy storage device according to the third embodiment of the present application, wherein the power conversion device is used for electrically connecting a power generating device and the energy storage device.

[0018] A fifth embodiment of the present application provides a power-consuming device comprising a battery cell according to the first embodiment of the present application, a battery device according to the second embodiment of the present application, an energy storage device according to the third embodiment of the present application or an energy storage system according to the fourth embodiment of the present application, wherein the battery cell or the battery device is used for storing or providing electrical energy. BRIEF DESCRIPTION OF THE DRAWING

[0019] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings, which are to be used in the embodiments of the present application, are briefly described below. Of course, the accompanying drawings described below are only some of the embodiments of the present application, and other accompanying drawings can be derived from the accompanying drawings by a person with normal technical knowledge without any creative effort. Fig. Figure 1 is a schematic representation of a width B, a height H and a thickness T of a battery cell in an embodiment of the present application; Fig. Figure 2 is a schematic representation of the battery cell in an embodiment of the present application; Fig. 3 is a decomposition representation of the in the Fig.2 battery cell shown in an embodiment of the present application; Fig. Figure 4 shows a schematic representation of a battery module in an embodiment of the present application; Fig. Figure 5 shows a schematic representation of a battery pack in an embodiment of the present application; Fig. 6 is a decomposition representation of the in the Fig. 5 battery packs shown in an embodiment of the present application; Fig. Figure 7 shows a schematic representation of a power-consuming device which uses a battery cell as a power source, in an embodiment of the present application.

[0020] The attached drawings may not be to scale. Reference symbol list:

[0021] 1 Battery pack; 2 Upper box; 3 Lower box; 4 Battery module; 5 Battery cell; 51 Housing body; 52 Electrode assembly; 53 End cap. DETAILED DESCRIPTION

[0022] The specific embodiments of the present application are described in more detail below in conjunction with the accompanying drawings and exemplary embodiments. The detailed description of the following exemplary embodiments and the accompanying drawings serve to illustrate the principles of the present application by way of example, but cannot be used to limit the scope of the present application; that is, the present application is not limited to the described exemplary embodiments.

[0023] The following sections disclose in detail embodiments of an active anode material and its manufacturing process, a cathode foil, an anode foil, a secondary battery, a battery module, a battery pack, and a current-consuming device of the present application with appropriate reference to the accompanying drawings. However, there will be instances where an unnecessarily detailed description is omitted. For example, detailed descriptions of things that are already well known and repeated descriptions of the same structure are omitted. This is to avoid making the following description unnecessarily long and to facilitate understanding for the person skilled in the art.Furthermore, the attached drawings and the following description serve to provide a person skilled in the art with a complete understanding of the present application and are not intended to limit the subject matter specified in the claims.

[0024] The "range" disclosed here is defined in terms of a lower bound and an upper bound, with a particular range being defined by selecting a lower bound and an upper bound that establish the limits of that range. Ranges defined in this way can include or exclude end values ​​and can be combined in any way; that is, any lower bound can be combined with any upper bound to form a range. For example, if a range of 60 to 120 and 80 to 110 is specified for a particular parameter, then a range of 60 to 110 and 80 to 120 would also be expected. Furthermore, if the minimum values ​​of 1 and 2 and the maximum values ​​of 3, 4, and 5 are specified, then the following ranges can be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.Unless otherwise specified, the range "ab" denotes any combination of real numbers between a and b, where both a and b are real numbers. For example, the range "0-5" means that all real numbers between 0 and 5 are listed here, and 0-5 is simply a shorthand representation of the combination of these values. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to stating that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on.

[0025] Unless expressly stated otherwise, all embodiments and optional embodiments of the present application may be combined to form new technical solutions.

[0026] Unless expressly stated otherwise, all technical features of the present application, as well as optional technical features, may be combined to form a new technical solution.

[0027] Unless expressly stated otherwise, all steps of the present application may be carried out sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) carried out one after the other, or that it may include steps (b) and (a) carried out one after the other. The indication that the method may also include step (c) means, for example, that step (c) may be added to the method in any order; e.g., the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b).

[0028] Unless otherwise stated, references to "including" and "comprehensive" in this application refer to an open formulation. For example, the terms "including" and "comprehensive" may mean that other, unlisted components may also be included or contained.

[0029] Unless otherwise stated, the term "or" in this application is comprehensive. For example, the condition "A or B" is satisfied by any of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist). [Battery cell]

[0030] In the embodiments of the present application, the battery cell can be a secondary battery, i.e., a battery cell that can be recharged after the battery cell has been discharged, so that the active material can be activated and used again.

[0031] The battery cell can be a lithium-ion battery, a sodium-lithium-ion battery, a magnesium-ion battery, etc., and the embodiments of the present application are not limited thereto.

[0032] A typical secondary battery comprises a cathode foil, an anode foil, a separator, and an electrolyte solution. During charging and discharging, active ions (e.g., lithium ions) are embedded and unembedded between the cathode and anode foils. The separator, located between the cathode and anode foils, primarily serves to prevent a short circuit between the cathode and anode while allowing the passage of active ions. The electrolyte solution mainly acts as a conductor for active ions between the cathode and anode foils.

[0033] An embodiment of the present application provides a battery cell comprising a housing and an electrode arrangement, wherein the electrode arrangement comprises a cathode foil, an anode foil, a separator, and an electrolyte solution; wherein a width B, a height H, and a thickness T of the battery cell satisfy 350 mm ≤ B ≤ 650 mm, 170 mm ≤ H ≤ 300 mm, and 50 mm ≤ T ≤ 90 mm; wherein the anode foil comprises a collector and an anode material layer provided on at least one side of the collector, wherein, when the battery cell is in a fully charged state, a heat dissipation Q of the anode material in the anode material layer in the electrolyte solution in which it is immersed satisfies the following: 180 J / g ≤ Q ≤ 600 J / g; where the fully charged state means that the charge level of the battery cell is 100%.

[0034] While increasing the size of the electrode array can satisfy the demand for high capacity, it also introduces problems such as high heat generation and poor heat dissipation. Furthermore, a large electrode array suffers from uneven current density distribution and increased impedance. The inventors have discovered that by limiting the heat generation of the anode material layer in the fully charged state to the area described above, the heat generation of the large electrode array can be significantly reduced, the overcharge performance improved, and the safety performance of the battery cell enhanced.

[0035] In some embodiments, the width B of the battery cell meets 350mm≤B≤400mm, 400mm ≤ B ≤ 500mm, 500mm ≤ B ≤ 560mm, 560mm ≤ B ≤ 600mm, or 600mm ≤ B ≤ 650mm.

[0036] In some embodiments, the height H of the battery cell meets the value 170mm ≤ H ≤ 200mm, 200mm ≤ H ≤ 250mm or 250mm ≤ H ≤ 300mm.

[0037] In some embodiments, the thickness T of the battery cell meets 50mm ≤ T ≤ 65mm, 65mm ≤ T ≤ 70mm, 70mm ≤ T ≤ 80mm or 80mm ≤ T ≤ 90mm.

[0038] Fig. Figure 1 is a schematic representation of a width B, a height H and a thickness T of a battery cell in an embodiment of the present application; The width B, the height H and the thickness T of the battery cell can be determined by measuring with a ruler.

[0039] Controlling the size of the battery cell is useful to avoid the problem of uneven current density distribution and increased impedance due to an excessively large battery cell size.

[0040] In some embodiments, when the battery cell is in a fully charged state, the heat dissipation Q of the anode material layer in the electrolyte solution in which it is immersed satisfies 180 J / g ≤ Q ≤ 200 J / g, 200 J / g ≤ Q ≤ 230 J / g, 230 J / g <_ Q ≤ 300 J / g, 300 J / g ≤ Q ≤ 360 J / g, 360 J / g ≤ Q ≤ 400 J / g, 400 J / g ≤ Q ≤ 500 J / g, 500 J / g ≤ Q ≤ 550 J / g or 550 J / g ≤ Q ≤ 600 J / g.

[0041] The heat dissipation Q of the anode material layer in the electrolyte solution in which it is immersed can be measured using the following procedure: (1) Disassemble the fully charged battery in a glove box, remove an appropriate amount of the anode foil, immerse the anode foil in DMC solvent for 2 minutes, wash off the remaining electrolyte solution and then dry for 8 hours, scrape off the active material layer on the electrode foil. (2) Preparation of the electrolyte solution: Mixing the vinyl carbonate and the methyl ethyl carbonate in a volume ratio of 3:7, adding LiPF6 to obtain the electrolyte solution, the concentration of LiPF6 being 1 mol / L.

[0042] A differential scanning calorimeter was used to measure the heat dissipation Q of the anode material layer, and the measurement procedure consisted of placing the anode material layer and the electrolyte solution in a mass ratio of 0.78:1 into a test crucible and increasing the temperature from 30°C to 450°C at a heating rate of 5°C / min.

[0043] The electrolyte solution formulation used in the measurements above is a relatively simple and conventional formulation, and the results obtained using this electrolyte solution to assess heat release are also representative of other electrolyte solution formulations. A person skilled in the art can also use other electrolyte solution formulations to measure Q.

[0044] In some embodiments, the charging voltage of the battery cell is 3.65 V.

[0045] In some embodiments, the immersion electrolyte solution comprises vinyl carbonate and methyl ethyl carbonate in a volume ratio of 3:7 and LiPF6 at a concentration of 1 mol / L. [Anode foil]

[0046] The anode foil comprises an anode collector and an anode material layer (anode film layer) which is provided on at least one surface of the anode collector, wherein the anode material layer comprises an active anode material.

[0047] For example, the anode collector has two surfaces that are opposite each other in its thickness direction, and the anode material layer is provided on one or both of the two surfaces opposite the anode collector.

[0048] In some embodiments, a first anode material layer comprises a first active anode material in granular form, wherein a second anode material layer comprises a second active anode material in granular form, wherein the particle size of the active anode material is Dv50; wherein Dv50 of the first active anode material and of the second active anode material is each independently 9 µm to 20 µm (e.g. 9 µm to 10 µm, 10 µm to 13 µm, 13 µm to 15 µm, 15 µm to 18 µm or 18 µm to 20 µm), optionally 10 µm to 15 µm.

[0049] Dv50 denotes the particle size reached when the cumulative fraction reaches 50%. Dv50 can be determined using a particle size analyzer and the laser diffraction method; in particular, it can be measured in accordance with standard GB / T 19077-2016.

[0050] In some embodiments, the first and second anode material layers each comprise a first active anode material and a second active anode material in granular form, wherein the specific surface area BET of the first active anode material and the second active anode material is each independently 1.3 m² 2 / g up to 3 m 2 / g, e.g. 1.3 m 2 / g up to 1.5 m 2 / g, 1.5 m 2 / g up to 2 m 2 / g, 2 m 2 / g up to 2.1 m 2 / g, 2.1 m 2 / g up to 2.9 m 2 / g, 2.9 m 2 / g up to 3 m 2 / g, is the amount.

[0051] The specific surface area BET of the active anode material can be measured using the following method: determination using the method for measuring specific surface area and static capacitance with reference to standard GB / T 19587-2017, and in particular, it can be measured according to an embodiment of the present application using the gas adsorption-type specific surface area measuring instrument by flow method.

[0052] The contact area between the graphite and the electrolyte solution can be adjusted by selecting the particle size and the specific surface area BET of the active anode material contained in each of the first and second anode material layers, thereby controlling the heat generation produced by the side reaction taking place between the graphite and the electrolyte solution and thus the heat dissipation of the anode material layer Q.

[0053] In some embodiments, the first and second active anode material layers can contain the same active anode material, e.g., both graphite, which can be identical graphite or graphite with different particle sizes and / or specific surface areas (BET). In the case of identical active anode materials, the difference in porosity between the first and second anode material layers can be achieved by adjusting the formulation of the first and second anode material layers, thereby improving the battery kinetics.

[0054] In some embodiments, the anode material layer comprises a first anode material layer and a second anode material layer, the second anode material layer being located on the side of the first anode material layer facing away from the collector, wherein the ratio of the thickness t2 of the second anode material layer to the thickness t1 of the first anode material layer is 2 / 3 ≤ t2 / t1 ≤ 1.5. In some embodiments, the porosity of the second anode material layer is greater than the porosity of the first anode material layer.

[0055] In some embodiments, the porosity of the two layers can be adjusted by modifying the formulation of the coated slurry for the first anode material layer and the coated slurry for the second anode material layer. For example, the coated slurry for the second anode material layer can be formulated to contain more conductive carbon and less graphite than the coated slurry for the first anode material layer. After cold pressing the coating, this results in a slightly lower pressing density of the second anode material layer than the first, which can lead to a higher porosity of the second anode material layer.

[0056] In some embodiments, the ratio of the thickness t2 of the second anode material layer to the thickness t1 of the first anode material layer is 2 / 3 ≤ t2 / t1 ≤ 1 or 1 ≤ t2 / t1 ≤ 1.5.

[0057] In some embodiments, the thickness t1 of the first anode material layer and the thickness t2 of the second anode material layer are each independently selected from 57 µm to 87 µm, for example 57 µm to 60 µm, 60 µm to 65 µm, 65 µm to 70 µm, 70 µm to 72 µm, 72 µm to 80 µm or 80 µm to 87 µm.

[0058] In some embodiments, the porosity of the first anode material layer and the porosity of the second anode material layer are each independently selected from 25% to 36%, for example 25% to 26%, 26% to 28%, 28% to 30%, 30% to 32%, 32% to 34% or 34% to 36%.

[0059] The interfacial impedance of a single-layer coating is higher than that of a multi-layer coating. Using a multi-layer anode material for the anode can, on the one hand, reduce the binder content in the formulation of each layer and thus lower the interfacial impedance; on the other hand, it can also improve the uniformity of the binder distribution in the electrode foil and increase the current density; furthermore, the use of a stepped distribution design with sparse porosity on the top and dense porosity on the bottom is more conducive to complete wetting of the electrolyte solution, which serves to conduct lithium ions and accelerate the conduction velocity of the ions at the anode surface, ultimately improving the kinetics of the battery cell and increasing the battery's lifespan.Accordingly, the anode adopts the design described above, which is particularly suitable for large-format electrode arrangements with high capacity.

[0060] The thickness of the first anode material layer and the thickness of the second anode material layer can be measured using the following method:

[0061] Taking a section of the anode foil and viewing it through tomographic SEM, an obvious boundary line of the double-layer coating can be seen. Taking the boundary line as the baseline, measure the thickness from the boundary line to the surface of the collector, i.e., the thickness of the first active layer; and measure the thickness from the boundary line to the upper surface of the electrode foil, i.e., the thickness of the second active layer.

[0062] The porosity of the anode foil can be measured using the following method:

[0063] Take a section of the anode foil's cut surface and observe the bilayer coating structure using tomographic SEM. Randomly acquire an SEM image of the cut surface within a specific field of view, ensuring that it captures the entire first active layer and the second active layer. By measuring the total area S1 of the first active layer and the total area R1 of the first active material within the first active layer, the porosity of the first active layer is defined as (1-R1 / S1) × 100%; by measuring the total area S2 of the second active layer and the total area R2 of the second active material within the second active layer, the porosity of the second active layer is defined as (1-R2 / S2) × 100%.

[0064] In some embodiments, the anode collector can be a metal foil or a composite collector. For example, a copper foil can be used as the metal foil. The composite collector can comprise a base layer of polymeric material and a metal layer formed on at least one surface of the polymeric base layer. The composite collector can be formed by depositing metallic material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as a substrate made of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0065] In some embodiments, the active anode material may be an active anode material known in the art for use in batteries. The active anode material may, for example, comprise at least one of the following materials: synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate. The silicon-based material may be at least one of monolithic silicon, silicon oxides, silicon-carbon complexes, silicon-nitrogen complexes, and silicon alloys. The tin-based material may be at least one of monolithic tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as active anode materials in batteries may also be employed.It is possible that only one of these active anode materials is used, or that more than two are used in combination.

[0066] In some embodiments, the anode film layer optionally comprises a binder. For example, the binder may be at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0067] In some embodiments, the anode film layer optionally further comprises a conductive material. For example, the conductive material can be at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dot, carbon nanotubes, graphene, and carbon nanofibers.

[0068] In some embodiments, the anode film layer optionally includes further additives, such as thickening agents (e.g. sodium carboxymethylcellulose (CMC-Na)), etc.

[0069] In some embodiments, the anode foil can be manufactured as follows: Dispersing the components described above for the production of the anode foil, such as the active anode material, the conductive agent, the binder and other components, in a solvent (e.g. deionized water) to form an anode slurry; applying the anode slurry to the anode collector and obtaining the anode foil after drying, cold pressing and other processes. [Electrolyte solution]

[0070] The electrolyte serves as an ion conductor between the cathode foil and the anode foil. The present application does not impose any specific restrictions regarding the type of electrolyte, which can be selected as needed. For example, the electrolyte can be in liquid, gel, or solid form.

[0071] In some embodiments, the electrolyte is liquid and contains an electrolyte salt and a solvent.

[0072] In some embodiments, the electrolyte salt may be at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(trifluorosulfonyl)amide, lithium bis(trifluoromethanesulfonyl)amide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalic acid borate, lithium di(oxalic acid)borate, lithium difluorodioxygenophosphate and lithium tetrafluorooxalic acid phosphate.

[0073] In some embodiments, the solvent may be at least one of vinyl carbonate (ethylidene carbonate), propylene carbonate (propylidene carbonate), methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylenepropyl carbonate, ethylenepropyl carbonate, butylidene carbonate, ethylidene fluorocarbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0074] In some embodiments, the electrolyte solution contains vinyl carbonate (EC), with the mass fraction of vinyl carbonate in the electrolyte solution being 15% to 25% (e.g., 15% to 18%, 18% to 20%, or 20% to 25%). Vinyl carbonate has a high dielectric constant and good dissolving capacity for lithium salt during electrolysis, but its viscosity is high, and an excessive addition degrades the conductivity of the electrolyte solution and also impairs its wettability. Wetting the electrolyte solution is more difficult with a large, high-capacity electrical core than with a smaller, lower-capacity core.The addition of vinyl carbonate with a mass fraction in the above range can, on the one hand, exploit its high dielectric constant and its good ability to dissolve lithium salt during electrolysis, and on the other hand, give the electrolyte solution sufficient conductivity and good wettability.

[0075] In some embodiments, the electrolyte solution contains propylene carbonate (PC), with the mass fraction of propylene carbonate in the electrolyte solution being 1% to 8% (e.g., 1% to 2%, 2% to 4%, 4% to 6%, or 6% to 8%). Propylene carbonate has a high dielectric constant and a low freezing point, and the addition of propylene carbonate to the electrolyte solution helps to increase the electrical conductivity of the electrolyte solution at low temperatures, thereby improving the battery's low-temperature performance; however, an excessive addition tends to embed itself, along with the lithium ions, in the active anode material, leading to detachment of the active anode material and a reduction in battery lifespan.The addition of propylene carbonate with a mass fraction in the above range can, on the one hand, improve the performance of the battery at low temperatures and, on the other hand, does not adversely affect the cycle life of the battery.

[0076] In some embodiments, the electrolyte solution optionally includes an additive. For example, the additive may include a film-forming additive for the anode and a film-forming additive for the cathode, and may also include an additive that can improve certain battery properties, such as an additive to improve the battery's overcharge performance, an additive to improve the battery's high- or low-temperature performance, etc. [Housing]

[0077] The battery cell of the present application may comprise a housing. The housing may be, among other things, a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film. In some embodiments, the housing may be either a sealed or an unsealed structure. If the housing is unsealed, for example, it serves to protect the electrode assembly. A sealing pouch is also arranged between the housing and the electrode assembly, enclosing both the electrode assembly and the electrolyte solution. In particular, the sealing pouch may be a pouch-like insulating element or an aluminum-plastic film. If the housing is sealed, it encloses components such as the electrode assembly and the electrolyte solution.

[0078] In some embodiments, the housing comprises a housing body, wherein an inner surface and / or an outer surface of the housing body comprises a coating layer, wherein the coating layer has a thermally conductive function; A coating layer with a thermally conductive function is provided on the inner surface and / or the outer surface of the housing body, which promotes heat conduction from the interior of the battery cell and improves the heat dissipation capability.

[0079] Furthermore, the casing may also have a heat-resistant function to prevent the casing from melting due to heat generation, thereby improving the safety performance of the battery cell.

[0080] In some embodiments, the total thickness of the coating layer is 1 µm to 12 µm (e.g. 1 µm to 4 µm, 4 µm to 8 µm or 8 µm to 12 µm).

[0081] It is possible to select a material for the coating layer that is both thermally conductive and heat-resistant, or to add a heat-resistant material to the coating layer. In some embodiments, the coating layer comprises one or more of the following substances: aluminum nitride (AlN), BeO, SiC, boron nitride, to achieve thermal conductivity. SiC and boron nitride are both thermally conductive and heat-resistant. In some embodiments, the coating layer further comprises one or more of the following substances: aluminum trioxide, boehmite, zirconium oxide, titanium oxide, Si3N4, to achieve heat resistance.

[0082] In some embodiments, an inner surface of the housing body comprises a coating layer, the thickness of which is 1 µm to 4 µm.

[0083] In some embodiments, an outer surface of the housing body comprises a coating layer, the thickness of which is 1 µm to 4 µm.

[0084] In some embodiments, the inner surface and the outer surface of the housing body comprise a coating layer, wherein the thickness of the coating layer on the inner surface and the outer surface is independently 1 µm to 4 µm.

[0085] In some embodiments, the coating layer of the inner surface comprises aluminium nitride and boehmite.

[0086] In some embodiments, the coating layer of the outer surface comprises aluminium nitride and boehmite.

[0087] The thickness of the coating layer on the inner or outer surface of the housing body can be measured using the following method:

[0088] Taking a part of the housing body, polishing the cut surface, placing it under a CCD microscope, observing the coating layer on the inner and outer surfaces of the cut surface, and measuring the thickness of the coating layer.

[0089] The battery cell can be, for example, a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell of other shapes, and the prismatic battery cell includes a battery cell with a square casing, a battery cell in the shape of a razor blade, a multi-prismatic battery, a multi-prismatic battery, for example a hexapod battery, etc., with no particular restrictions in the present application.

[0090] In some embodiments, the housing comprises an end cap and a housing body, wherein the housing body is provided with an opening and the end cap covers the opening. The housing body may be provided with one or more openings. The end cap may also be provided in one or more openings.

[0091] In some embodiments, the housing is provided with at least one electrode clamp, the electrode clamp being electrically connected to the electrode tab. The electrode clamp can be connected to the electrode tab directly or indirectly via a collector component. The electrode clamp can be located on an end cap or on the housing body.

[0092] In some embodiments, the housing is equipped with a pressure relief mechanism. A pressure relief mechanism is used to vent the internal gas of the battery cell.

[0093] For example, the battery cell is actuated to relieve internal pressure or temperature when the internal pressure or temperature reaches a predetermined threshold. When the internal pressure or temperature reaches the predetermined threshold, the pressure relief mechanism is activated, or a weak structure within the pressure relief mechanism is ruptured to create an opening or passage that can be used to release the internal pressure or temperature. The threshold determination varies depending on the design requirements. The threshold may depend on the material of one or more of the cathode foil, the anode foil, the electrolyte, and the separator within the battery cell.

[0094] For example, the pressure relief mechanism can be molded as one piece with the housing.

[0095] For example, the pressure relief mechanism can also be provided separately from the housing and connected to the housing.

[0096] The “actuation” referred to in the present application means that the pressure relief mechanism generates an action or is activated to a specific state so that the temperature and / or pressure inside the battery cell can be relieved. The actions of the pressure relief mechanism may include, but are not limited to, the movement of the components within the pressure relief mechanism to form an exhaust channel, and at least one part of the pressure relief mechanism tearing, breaking, rupturing, or opening, and the like. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substances within the battery cell are discharged as emissions from the actuated part.In this way, it is possible to subject the battery cell to pressure and temperature relief under controlled pressure or controlled temperature, thereby avoiding potentially more serious accidents.

[0097] In some embodiments where the housing is an unsealed structure, the pressure relief mechanism may be provided as a through-hole for the venting of gases within the battery cell.

[0098] Emissions from the battery cell referred to in this application include, but are not limited to: the electrolyte, the dissolved or split cathode foil and anode foil, fragments of the separator, gases of high temperature and pressure generated by the reaction, flames and the like. [Cathode foil]

[0099] In some embodiments, the cathode foil comprises a cathode material layer, wherein the cathode material layer comprises an active cathode material, the active cathode material comprising a lithium-containing phosphate. Optionally, the lithium-containing phosphate optionally comprises lithium iron phosphate (e.g., soft carbon-coated lithium iron phosphate).

[0100] In some embodiments, the cathode can be a cathode foil, and the cathode foil can comprise a cathode collector and a cathode material layer provided on at least one surface of the cathode collector. For example, the cathode collector has two surfaces opposite each other in its thickness direction, and the active cathode material is provided on one or both of the two surfaces opposite the cathode collector.

[0101] For example, the cathode collector can be a metal foil, a conductive polymer material, a carbon material, or a composite collector. A metal foil can be made of, for example, a pure metal, an alloy, or a surface-treated metal, including but not limited to, stainless steel, copper, aluminum, nickel, titanium, or silver. The composite collector can consist of a base layer of polymer material and a metal layer. A composite collector can be formed by depositing metallic material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) onto a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0102] In some embodiments, the battery cell is a lithium-ion battery, and the active cathode material may be an active cathode material known in the art for use in lithium-ion batteries. The active cathode material may comprise at least one lithium-containing phosphate, lithium transition metal oxide, and corresponding modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials suitable for use as active cathode materials in batteries may also be used. It is possible to use only one of these active cathode materials or to use more than two in combination. Phosphates include, for example, lithium iron phosphate (e.g., LiFePO4, which may also be abbreviated as LFP), a lithium iron phosphate-carbon composite, lithium manganese phosphate (e.g.,LiMnPO4), a compound of lithium manganese phosphate and carbon, a compound of lithium ferromanganese phosphate and lithium manganese iron phosphate and carbon. Layered transition metal oxides include, for example, at least one of the following compounds: lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2, also known as NCM 333 can be abbreviated as LiNi 0,5 Co 0,2 Mn 0,3 O2, also known as NCM 523 can be abbreviated as LiNi 0,5 Co 0,25 Mn 0,25 O2, also known as NCM 211 can be abbreviated as LiNi 0,6 Co 0,2 Mn 0,2 O2, also known as NCM 622 can be abbreviated as LiNi 0,8 Co 0,1 Mn 0,1 O2, also known as NCM811 (can be abbreviated) and lithium nickel cobalt aluminum oxide (e.g., LiNi 0,85 Co 0,05 Al 0,05 O2) and modified compounds thereof, and the like. The term "modified compound" refers to a substance obtained by modification, such as doping or coating, of the substance described above.

[0103] In the listing of active cathode materials in the present application, the molar content of oxygen is only a theoretical state value; the lattice release of oxygen leads to a change in the molar content of oxygen, and in practice the molar content of oxygen will fluctuate.

[0104] In some embodiments, the cathode film layer optionally comprises a binder. For example, the binder may comprise at least one of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0105] In some embodiments, the cathode film layer optionally further comprises a conductive material. For example, the conductive material may comprise at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dot, carbon nanotubes, graphene, and carbon nanofibers.

[0106] In some embodiments, the cathode can consist of a foam metal. This foam metal can be nickel foam, copper foam, aluminum foam, a foam alloy, or carbon foam. When the foam metal is used as the cathode, its surface does not need to be coated with an active cathode material, but it can, of course, be. For example, an active cathode material can be embedded in or deposited within the foam metal.

[0107] In some embodiments, the cathode foil can be produced as follows: Dispersing the components described above for the production of the cathode foil, such as the active cathode material, the conductive agent, the binder and any other components, in a solvent (e.g. N-methylpyrrolidone) to form a cathode slurry; applying the cathode slurry to the cathode collector and obtaining the cathode foil after drying, cold pressing and other processes. [Separator]

[0108] In some embodiments, the secondary battery further comprises a separator. The present application does not impose any specific restrictions regarding the type of separator, and any known separator with a porous structure and good chemical and mechanical stability may be selected.

[0109] In some embodiments, the separator material can be at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film without any particular restriction. If the separator is a multi-layer composite film, the materials of the layers can be the same or different without any particular restriction.

[0110] In some embodiments, the cathode foil, the anode foil and the insulating film can be assembled into an electrode arrangement by a winding process or a stacking process.

[0111] The present application enables the production of a large-format battery cell with high capacity, low heat generation, improved overcharging behavior, and enhanced battery cell safety. In some embodiments, the battery cell capacity is greater than or equal to 500 Ah, such as 500 Ah to 640 Ah, 640 Ah to 730 Ah, or 730 Ah to 1100 Ah.

[0112] The capacity of the battery cell can be tested using the following procedure:

[0113] The battery cell is tested for its capacity using a charge / discharge meter at 25°C. First, the battery cell is discharged to 2.5 V at a discharge rate of 0.25P and left for 10 minutes; then it is charged to 3.65 V at a charge rate of 0.25P and left for 30 minutes, then it is discharged to 2.5 V at a discharge rate of 0.25P, and the capacity of this discharge is recorded as the battery cell's capacity.

[0114] In Fig. Figure 2 shows, as an example, a battery cell 5 with a rectangular structure.

[0115] In some embodiments, such as in Fig.As shown in Figure 3, the housing can comprise a housing body 51 and an end cap 53. The housing body 51 can include a base plate and side plates connected to the base plate, the base plate and the side plates forming a receiving cavity. The housing 51 has an opening that communicates with the receiving cavity, and the end cap 53 can serve to cover the opening to close the receiving cavity. The cathode foil, the anode foil, and the separator can be assembled into an electrode assembly 52 by a winding or stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte solution is exchanged into the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and the person skilled in the art can make the selection according to specific requirements. [Battery device]

[0116] The battery apparatus in an embodiment of the present application can comprise one or more battery cells to provide a voltage and capacity. The battery cell assembly can comprise a plurality of battery cells, wherein the plurality of battery cells are connected in series, parallel, or in a mixed configuration by a converging element.

[0117] In some embodiments, a battery cell assembly is typically formed by arranging several battery cells.

[0118] For example, the battery cell arrangement can be a battery module, where the battery module comprises a plurality of battery cells arranged and secured to form an independent module. For example, the battery module can be formed by bonding the multiple battery cells together.

[0119] Fig. Figure 4 shows a battery module 4 as an example. As in Fig. As shown in Figure 4, the multiple battery cells 5 in the battery module 4 can be arranged sequentially along a longitudinal direction of the battery module 4. Of course, they can also be arranged in any other desired manner. Furthermore, the multiple battery cells 5 can be secured by fastening elements.

[0120] Optionally, the battery module 4 can also include a casing with a receiving space in which the multitude of battery cells 5 are housed.

[0121] In some embodiments, the battery device can be a battery pack, wherein the battery pack comprises a box and one or more battery cell arrangements, the battery cell arrangements being contained in the box.

[0122] For example, the battery cell arrangement can be a battery module; the battery cell arrangement can be accommodated in the box by attaching the battery module to the box.

[0123] For example, the battery cell arrangement can also be incorporated into the box by attaching a large number of battery cells directly into the box.

[0124] For example, the enclosure can comprise a first enclosure and a second enclosure. The first and second enclosures are attached to each other in such a way that an enclosed space is formed inside the enclosure, which houses the battery cell assembly. "Enclosed" here means covered or sealed, and this space can be either sealed or unsealed. The first enclosure can be a top cover or a bottom plate.

[0125] For example, the box can comprise a top cover, a frame, and a base plate. The top cover and the base plate are each connected to the frame, creating an enclosed space inside the box to house the battery cell assembly.

[0126] In some embodiments, the box can be part of the vehicle's chassis structure. For example, parts of the box can be at least part of the vehicle's floor, or parts of the box can be at least part of a cross member and a longitudinal member of the vehicle.

[0127] Fig. 5 and Fig. Figure 6 shows a battery pack 1 as an example. As in Fig. 5 and Fig.As shown in Figure 6, the battery pack 1 can comprise a battery housing and a plurality of battery modules 4 arranged within the battery housing. The battery housing comprises an upper housing 2 and a lower housing 3, the upper housing 2 serving to cover the lower housing 3 and form an enclosed space for receiving the battery module 4. The plurality of battery modules 4 can be arranged within the battery housing in any desired configuration.

[0128] The technical solutions described in the embodiments of the present application are all applicable to various power-consuming devices that use battery cells, such as mobile phones, portable devices, laptops, battery cars, electric toys, power tools, electric vehicles, ships and spacecraft, e.g. aircraft, rockets, space shuttles and spacecraft.

[0129] Fig.Figure 7 shows an example of a power-consuming device. The power-consuming device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the battery cell of this power-consuming device, a battery pack or battery module can be used. [EXECUTION EXAMPLE]

[0130] The following describes exemplary embodiments of the present application. The embodiments described below are exemplary, serve to explain the present application, and cannot be construed as limiting the present application. Unless specific techniques or conditions are indicated in the exemplary embodiments, they correspond to the techniques or conditions described in the relevant literature or to the information in the product specification. The reagents or instruments used without manufacturer identification are all commercially available products. General testing procedure:

[0131] The following parameters are tested according to the procedure described above:

[0132] The particle size and specific surface area BET of the active anode material, the width B, the height H and the thickness T of the battery cell, the heat dissipation of the anode material layer, the porosity of the anode foil, the capacity of the battery cell, the thickness of the coating layer on the inner surface or the outer surface of the casing body, the thickness of the first anode material layer and the thickness of the second anode material layer. Overload test procedure

[0133] For the overcharge test, reference is made to the overcharge test standard in GBT 36276-2023, and the maximum temperature of the large area of ​​the battery cell is recorded during the overcharge test. Test procedures for the cycle life of batteries

[0134] The battery is charged at 1C to 3.65V at 25°C, then charged at 0.05C at constant voltage, left to stand for 10 minutes, discharged at 1C to 2.5V, the capacity of the first discharge cycle is recorded as C0, and the charge and discharge cycle test is performed according to the above procedure, and the capacity retention rate after the cycle is calculated. The capacity retention rate after cycles at 25°C is as follows: Capacity retention rate after the nth cycle = (Discharge capacity after the nth cycle / Discharge capacity of the first cycle C0) * 100%. Test for the fast charging performance of the batteries at low temperatures

[0135] The battery is charged at 1C to 3.65V at 25°C, then charged at 0.05C at constant voltage, left to stand for 10 minutes, discharged at 1C to 2.5V, and the discharge capacity recorded as D0. Next, the battery is charged at 0.5D0 to 3.65V at -10°C, and the charge capacity recorded as D1; ​​then it is discharged at 1D0 to 2.5V and left to stand for 30 minutes; then it is discharged at 2D0 to 3.65V, and the charge capacity recorded as D2; then the capacity maintenance rate during fast charging at low temperature = D2 / D1. Example 1 [Production of the cathode foil]

[0136] The active cathode material lithium iron phosphate (LiFePO4), the conductive agent Super P and the binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 97:1:2, the solvent N-methylpyrrolidone is added and the cathode slurry is obtained by homogeneous stirring; the cathode slurry is applied evenly to the aluminum foil of the cathode collector on both sides and the cathode foil is obtained by drying, cold pressing and cutting. [Production of the anode foil]

[0137] (1) The first active material graphite is mixed with the conductive agent Super-P, the dispersing agent CMC and the binder SBR in a mass ratio of 96.4:0.4:1.0:2.2 in an appropriate amount of deionized water by thorough stirring, so that a homogeneous anode slurry A1 is obtained;

[0138] (2) The second active material graphite is mixed with the conductive agent Super-P, the dispersing agent CMC and the binder SBR in a mass ratio of 96.0:0.7:1.1:2.2 in an appropriate amount of deionized water by thorough stirring, so that a homogeneous anode slurry A2 is obtained;

[0139] (3) The anode slurry A1 is applied to the copper foil of the anode collector, and the anode slurry A2 is applied to A1, and the anode foil with a double-sided coating is obtained after drying, cold pressing, forming and cutting the electrode tab and cutting. [Preparation of the electrolyte solution]

[0140] In a glovebox filled with argon gas (water content <10 ppm, oxygen content <1 ppm), vinyl carbonate (EC), methyl methyl carbonate (EMC) and propylene carbonate (PC) were mixed in a mass ratio of 18:78:4 to obtain an electrolyte solvent, and then LiPF6, a sufficiently dried lithium salt, was added to the above solvent and mixed, and an electrolyte solution with a concentration of the lithium salt of 1 mol / L was prepared. [Separator]

[0141] A polyethylene film is chosen as the separator. [Production of the battery cell]

[0142] The cathode foil, separator, and anode foil are stacked sequentially, with the separator positioned between the cathode and anode foils, providing insulation. The bare electrode assembly is formed after winding, and the electrode assembly is formed after welding the cathode and anode tabs. The electrode assembly is then installed in a housing, and after injecting the prepared electrolyte solution, the lithium-ion battery is finally manufactured. Following encapsulation, curing, forming, shaping, and capacity testing, the battery is completed.

[0143] In embodiments 1 to 4 and comparative example 1, only the particle size and the specific surface area of ​​the active anode material differ, and the other conditions are the same.

[0144] As can be seen from Table 1, a change in the particle size and specific surface area of ​​the active anode material affects the heat dissipation of the active anode layer, all other conditions being equal. The smaller the particle size and the larger the specific surface area of ​​the active anode material, the greater the amount of heat dissipated by the active anode layer, which in turn leads to a higher temperature across the large surface area of ​​the battery cell under overcharge conditions. The temperature rise of the battery cell can be effectively improved by modifying the design of the active anode material in the embodiments described above.

[0145] In embodiments 5 to 6, the thickness of the first and second active material layers is changed compared to embodiment 3, and in embodiment 7, the porosity of the first and second active material layers is changed compared to embodiment 3, while the other conditions remain the same. Table 2 number Thickness t1 of the first active material layer (µm) Thickness t2 of the second active material layer (µm) t2 / t1 Porosity of the first active material layer Porosity of the second active material layer Battery cell capacity (Ah) Capacity maintenance rate for 1000 cycles (cls) at 25°C Capacity retention rate during fast charging at -10°C Maximum temperature of a large area of ​​the overcharged battery cell (°C) Example 3 72 72 1,0 28% 34% 730 94,5% 96,4% 75 Example 5 87 57 0,7 28% 34% 730 94,3% 96,0% 75 Example 6 57 87 1,5 28% 34% 730 94,7% 96,5% 75 Example 7 72 72 1,0 30% 25% 730 93,3% 95,3% 75

[0146] As can be seen from embodiments 3, 5, 6 and 7, the porosity of the second anode material layer is greater than the porosity of the first anode material layer, which contributes to improving the cycle performance and fast charging performance of the battery.

[0147] In embodiments 8 to 11, the composition of the solvent in the electrolyte solution is changed compared to embodiment 3, while the other conditions remain the same. Table 3 number EC content PC salary Battery cell capacity (Ah) Capacity maintenance rate for 1000 cycles (cls) at 25°C Capacity retention rate during fast charging at -10°C Maximum temperature of a large area of ​​the overcharged battery cell (°C) Example 3 18% 4% 730 94,5% 96,4% 75 Example 8 15% 4% 730 94,2% 96,6% 71 Example 9 25% 4% 730 94,0% 96,0% 80 Example 10 18% 1% 730 94,4% 94,9% 70 Example 11 18% 8% 730 94,0% 96,2% 82

[0148] As can be seen from embodiments 3 and 8 to 11, an increase in the EC content or PC content increases the heat generation of the battery; the addition of a suitable PC content contributes to improving the performance of the battery at low temperatures.

[0149] In embodiments 12 to 14, only the coating layer of the inner surface and / or the outer surface is changed compared to embodiment 3, while the other conditions remain the same. Table 4 number Is there a coating layer on the inner surface? Is there a coating layer on the outer surface? Thickness of the coating layer on the inner surface (µm) Thickness of the coating layer on the outer surface (µm) Thermally conductive, high-temperature resistant material in the coating layer of the inner surface Thermally conductive, high-temperature resistant material in the coating layer of the outer surface Battery cell capacity (Ah) Maximum temperature of a large area of ​​the overcharged battery cell (°C) Example 3 No Yes / 4 / Aluminum nitride + boehmite 730 75 Example 12 Yes No 4 / Aluminum nitride + boehmite / 730 68 Example 13 Yes Yes 4 4 Aluminum nitride + boehmite Aluminum nitride + boehmite 730 64 Example 14 No No / / / / 730 81

[0150] As can be seen from embodiments 3 and 14 to 16, a coating layer of a thermally conductive, high-temperature-resistant material on the inner surface and / or the outer surface of the housing body can effectively improve the temperature rise of the battery cell.

[0151] In embodiments 15 to 17, only the size of the electrode arrangement and the capacity of the battery cell are changed compared to embodiment 3, while the other conditions remain the same. Table 5 number Heat dissipation of the active anode layer (J / g) Width B (mm) Height (mm) Thickness T (mm) Battery cell capacity (Ah) Capacity maintenance rate for 1000 cycles (cls) at 25°C Capacity retention rate during fast charging at -10°C Maximum temperature of a large area of ​​the overcharged battery cell (°C) Example 3 360 400 200 70 730 94,5% 96,4% 75 Example 15 360 560 200 70 1100 93,2% 95,2% 98 Example 16 360 350 200 70 640 94,6% 96,5% 66 Example 17 360 350 170 65 500 94,7% 96,6% 52

[0152] For a given heat output per unit weight of the active substance, the heat output and the temperature increase with the battery cell's capacity and the amount of active substance present. As can be seen from embodiments 3 and 15 to 17, the probability of a temperature increase in the battery cell increases with the size of the electrode array and the battery cell's capacity.

[0153] However, by using the design of the anode foil and the electrolyte solution in the above embodiments, the temperature rise of the battery cell can be effectively improved at large sizes and capacities.

[0154] Although the present application is described with reference to preferred embodiments, various improvements can be made to it and parts thereof can be replaced by equivalents without departing from the scope of the present application. In particular, any of the technical features mentioned in the various embodiments can be combined in any way, as long as there is no structural conflict. The present application is not limited to the particular embodiments disclosed herein, but encompasses all technical solutions that fall within the scope of the claims.

Claims

[1] Battery cell comprising a casing and an electrode assembly, wherein the electrode assembly comprises a cathode foil, an anode foil, a separator and an electrolyte solution; wherein a width B, a height H and a thickness T of the battery cell satisfy 350 mm ≤ B ≤ 650 mm, 170 mm ≤ H ≤ 300 mm and 50 mm ≤ T ≤ 90 mm; wherein the anode foil comprises a collector and an anode material layer provided on at least one side of the collector, wherein, when the battery cell is in a fully charged state, a heat dissipation Q of the anode material layer in the electrolyte solution in which it is immersed satisfies the following: 180 J / g ≤ Q ≤ 600 J / g; wherein the fully charged state means that the state of charge of the battery cell is 100%. [2] Battery cell according to claim 1, wherein a first anode material layer comprises a first active anode material in a granular form, wherein a second anode material layer comprises a second active anode material in a granular form, wherein the particle size of the active anode material is Dv50; wherein Dv50 of the first active anode material and of the second active anode material is each independently 9 µm to 20 µm, optionally 10 µm to 15 µm. [3] Battery cell according to claim 1 or 2, wherein the first and second anode material layers each comprise a first active anode material and a second active anode material in granular form, wherein the specific surface area BET of the first active anode material and of the second active anode material is 1.3 m² 2 / g up to 3 m 2 / g. [4] Battery cell according to any one of claims 1 to 3, wherein the anode material layer comprises a first anode material layer and a second anode material layer, wherein the second anode material layer is provided on a side of the first anode material layer facing away from the collector, wherein a ratio of a thickness t2 of the second anode material layer to a thickness t1 of the first anode material layer 2 / 3≤t2 / t1≤1.5 is satisfied; and / or wherein the porosity of the second anode material layer is greater than the porosity of the first anode material layer. [5] Battery cell according to any one of claims 1 to 4, wherein the thickness t1 of the first anode material layer and the thickness t2 of the second anode material layer are each independently selected from 57 µm to 87 µm; and / or wherein the porosity of the first anode material layer and the porosity of the second anode material layer are each independently selected from 25% to 36%. [6] Battery cell according to any one of claims 1 to 5, wherein the electrolyte solution contains vinyl carbonate (EC), wherein the mass fraction of the vinyl carbonate in the electrolyte solution is 15 to 25%. [7] Battery cell according to any one of claims 1 to 6, wherein the electrolyte solution contains propylene carbonate (PC), wherein the mass fraction of the propylene carbonate in the electrolyte solution is 1 to 8%. [8] Battery cell according to any one of claims 1 to 7, wherein the housing comprises a housing body, wherein an inner surface and / or an outer surface of the housing body comprises a coating layer, wherein the coating layer has a thermally conductive function; the coating layer optionally also has a heat-resistant function; where the total thickness of the coating layer is 1 µm to 12 µm; the coating layer optionally comprises one or more of the following substances: AlN, BeO, SiC, boron nitride; wherein the coating layer may optionally further comprise one or more of the following substances: Si3N4, aluminium trioxide, boehmite, zirconium oxide, titanium oxide. [9] Battery cell according to any one of claims 1 to 8, wherein the capacity of the battery cell is greater than or equal to 500Ah. [10] Battery cell according to one of claims 1 to 9, wherein the cathode foil comprises a cathode material layer, wherein the cathode material layer comprises an active cathode material, wherein the active cathode material comprises a lithium-containing phosphate, wherein the lithium-containing phosphate optionally comprises lithium iron phosphate. [11] Battery cell according to any one of claims 1 to 10, wherein the charging voltage of the battery cell is 3.65 V. [12] Battery cell according to any one of claims 1 to 11, wherein the immersion electrolyte solution comprises vinyl carbonate and methyl ethyl carbonate in a volume ratio of 3:7 and LiPF6 in a concentration of 1 mol / L. [13] Battery device comprising several battery cells according to any one of claims 1 to 12. [14] Energy storage device comprising several battery cells according to any one of claims 1 to 12 or several battery devices according to claim 13, wherein the battery cells or the battery devices are used for storing or providing electrical energy. [15] Energy storage system comprising a power conversion device and an energy storage device according to claim 14, wherein the power conversion device is used to electrically connect a power generating device and the energy storage device. [16] Power consumption device comprising a battery cell according to any one of claims 1 to 12, a battery device according to claim 13, an energy storage device according to claim 14 or an energy storage system according to claim 15, wherein the battery cell or the battery device is used for storing or providing electrical energy.

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