4934 results about "Current collector" patented technology

The invention provides a pole piece and a manufacturing method thereof, a rolling system and a secondary battery, and the manufacturing method of the pole piece comprises the following steps: coating slurry on a current collector and drying to obtain a dried pole piece; the difference between the thickness of the dried pole piece and the preset thickness after rolling is used as the total rolling reduction; the dried pole piece is subjected to continuous multi-stage rolling, adjacent two-stage rolling is carried out, the percentage of the rolling reduction of the previous-stage rolling in the total rolling reduction is larger than or equal to the percentage of the rolling reduction of the next-stage rolling in the total rolling reduction, and the sum of the rolling reduction of all stages of rolling is equal to the total rolling reduction; in the multi-stage rolling, the rolling reduction of each stage of rolling is gradually reduced on the whole; and the multi-stage rolling is cold pressing. According to the manufacturing method of the pole piece, the multi-stage rolling mode is adopted, the rolling reduction decreasing and roller gap adjusting mode is adopted, the diameter, roughness and hardness of the roller body are combined to adapt to different rolling reduction, and finally the consistency of stress release and the pole piece is achieved.

An electromechanical joint provides rotational movement in at least two dimensions while conducting electrical power between orthogonal hubs. The joint, shaped as a cross, has four conical shafts positioned orthogonally and apart from each other within an interior of a housing. Apexes of the conical shafts face each other proximate a centroid of the housing. A conductive fluid, such as Galinstan, fills recesses between the conical shafts. Separate yokes attached to pairs of the hubs may impart forces on the shafts, causing the shafts to rotate within the conductive fluid around orthogonal axes. The conductive fluid provides simultaneous conduction of electrical power between the hubs. The yokes may be affixed respectively to a current collector and conductive arms of a work machine for improved movement and power conduction without the need for additional components.

Provided in the present disclosure are a sodium ion battery, a preparation method for the sodium ion battery, an electrical device and a hard carbon material. The sodium ion battery comprises a negative electrode sheet; the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer located on at least one surface of the negative electrode current collector; the negative electrode film layer comprises a hard carbon material. On the basis of measurement using the nitrogen adsorption method, the hard carbon material comprises a porous structure, and the porous structure comprises pores having a pore size of 2 nm-8 nm; on the basis of measurement using the nitrogen adsorption method, the pore volume of the pores having a pore size of 2 nm-8 nm is 0.0004 cm3 / g-0.0040 cm3 / g.

A secondary battery includes: a cylindrical case; an electrode assembly in the case and comprising a first tab protruding in a first direction and a second tab protruding in a second direction opposite to the first direction and connected to the case; a current collector plate in the case and comprising a current collector plate body portion connected to the first tab and a current collector plate liquid injection portion on the current collector plate body portion; a cap plate sealing the case so that the electrode assembly and the current collector plate are isolated from an outside; a rivet terminal including a rivet body portion coupled to the cap plate and a rivet liquid injection portion coupled to the current collector plate liquid injection portion; and a sealing portion sealing the current collector plate liquid injection portion and the rivet liquid injection portion.

Secondary battery, including a positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer, wherein the positive electrode film layer is arranged on at least one side of the positive electrode current collector and the positive electrode film layer comprises a positive electrode active material; a negative electrode sheet, wherein the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, wherein the negative electrode film layer is arranged on at least one side of the negative electrode current collector and the negative electrode film layer comprises a negative electrode active material, wherein the negative electrode active material comprises graphite and the powder compaction density of the negative electrode active material at 20,000 N is 1.5 g / cm³ 3 up to 1.85 g / cm³ 3 is; and an electrolyte comprising an organic solvent and an organic additive, wherein the organic solvent comprises a first solvent, the first solvent comprising cyclic carbonate, and the mass fraction of the first solvent, based on the total mass of the electrolyte, is 17% to 34%; wherein the organic additive comprises a first and a second additive, the first additive comprising vinylene carbonate and the second additive comprising an ethylene carbonate derivative, and the mass fraction of the first additive is 1.5% to 8% and the mass fraction of the second additive is 0.5% to 4%, each based on the total mass of the electrolyte.

The invention provides a negative electrode plate and a lithium ion battery, the negative electrode plate comprises a negative electrode current collector, a first negative electrode active layer and a second negative electrode active layer, the negative electrode current collector comprises a first region and a second region, the first region is arranged on the negative electrode current collector, the second region is located between the edge of the negative electrode current collector and the edge of the first region, the first negative electrode active layer is arranged in the first region, and the second negative electrode active layer is arranged in the second region; the Young's modulus of the second negative electrode active layer is greater than the Young's modulus of the first negative electrode active layer. According to the negative electrode plate provided by the invention, the second negative electrode active layer is arranged in the second region of the negative electrode current collector, the Young modulus of the second negative electrode active layer is greater than that of the first negative electrode active layer, and the relatively large Young modulus can inhibit volume expansion generated by the edge of the negative electrode plate in the charging and discharging process, so that the extension stress in the width direction of the negative electrode plate is reduced; the condition of corner damage caused by excessive extension of the negative plate is improved, so that the safety performance of the lithium ion battery is improved.

The invention provides rolling equipment, a current collector, a preparation method of the current collector, a pole piece, a battery and a device. A rolling device comprises a roller mechanism, a flow control mechanism and a power mechanism. The roller mechanism comprises at least two opposite rollers arranged at intervals and a flow control mechanism. The flow control mechanism is used for independently controlling the flow of the cooling medium in each cooling channel; the power mechanism is used for driving at least one roller to rotate. According to the rolling equipment, the roller diameter of the roller can be simply, effectively and flexibly adjusted by controlling the flow, so that the thickness of a rolled membrane material is adjusted, for example, a current collector with a large thickness in a tab area is prepared, the current collector is used for preparing an electrode pole piece, the problem of belt breakage in mass production of the electrode pole piece can be solved, and the production efficiency of the electrode pole piece is improved. And the yield of electrode plate production is improved.

Apparatus, systems, and methods described herein relate to the manufacture and use of electrochemical cells with a flame retardant mechanism. In some embodiments, an electrochemical cell includes a first current collector coupled to a first portion of a first pouch, the first current collector having a first electrode material disposed thereon. The electrochemical cell further includes a second current collector coupled to a second portion of the first pouch, the second current collector having a second electrode material disposed thereon. The electrochemical cell further includes a separator disposed between the first electrode material and the second electrode material, the first portion of the first pouch coupled to the second portion of the first pouch to enclose the electrochemical cell. The electrochemical cell further includes a flame retardant material coated to the first pouch and a second pouch, the second pouch enclosing the first pouch and the flame retardant material.

The invention provides a preparation method of a bipolar current collector based on a selective double-sided modified masking film. The preparation method comprises the following steps: depositing a Ni-Cr alloy layer on a single side surface of an aluminum substrate; one side of the masking film is etched to form a roughened surface, and the other side of the masking film is hydrophobic to form a hydrophobic surface; the roughened surface of the masking film and the surface, without the Ni-Cr alloy layer, of the aluminum matrix are pressed, and the edge is coated with curing glue; and placing the pressed and glued sample in an electroplating solution to electroplate a copper layer, finally cutting off an edge glue sealing area, and stripping the masking film. According to the preparation method, the masking film used for protecting the back surface of the aluminum substrate is subjected to double-sided differential treatment, the edge sealing technology is matched, and the Ni-Cr alloy is adopted for bottoming, so that the adhesive force between the copper plating layer and the aluminum substrate is improved, the risk of causing corrosion of a primary battery is reduced, the bipolar current collector which is firmly combined and has a pure interface can be prepared, and the service life of the bipolar current collector is prolonged. And a feasible solution is provided for realizing light-weight and high-performance current collectors for electronic devices such as lithium batteries and the like.

The utility model provides a battery negative pole piece and battery, battery negative pole piece includes current collector and active layer, active layer is coated on current collector at least one side surface, on the active layer is equipped with a plurality of groove structure along the length direction of current collector, groove structure extends along the width direction of current collector, and the groove structure is equipped with the groove structure. The active layer is divided into a plurality of areas by the plurality of groove structures along the length direction of the current collector, and each area is provided with a plurality of hole structures. According to the battery negative plate, the hole structures and the groove structures which are sequentially and alternately arranged in the length direction of the current collector are adopted, the liquid injection time of the battery is shortened, meanwhile, the liquid retention amount of electrolyte is increased, the wettability of the electrode is improved, the cycle life is prolonged, the service life of the battery is prolonged, and the performance stability of the battery is improved; and the problem that the battery performance is influenced due to poor wettability of the battery negative plate in the prior art is solved.

The invention relates to the technical field of crane electrical power supply, in particular to a crane sliding contact line power supply method which comprises the following steps: S1, monitoring the dynamic deformation quantity of a sliding contact line in real time, and obtaining the real-time contact resistance value of a current collector contact surface; s2, calculating the displacement compensation amount of the sliding contact line connector; s3, dynamically generating target contact pressure and transverse offset of the current collector; s4, a current collector executing mechanism is controlled to adjust the contact pressure and the transverse position; s5, if the contact resistance value is reduced to be below a preset threshold value and the deformation quantity fluctuation range is less than or equal to 0.5 mm, determining that the state is a stable power supply state; and S6, predicting a future deformation inflection point of the sliding contact line, and triggering an active compensation instruction before the inflection point. According to the invention, by constructing the slide wire power supply method integrating real-time monitoring, dynamic compensation and trend prediction, accurate adjustment and foresight control of the problem of unstable contact caused by deformation of the slide wire are realized, and the stability of the power supply system is improved.

The invention discloses a metro equipment mounting system, and relates to the technical field of metro equipment, the metro equipment mounting system comprises a collector shoe mounted on a metro vehicle chassis and a contact rail mounted beside a metro rail, a shoe body of the collector shoe is in sliding contact with the contact rail, and the collector shoe comprises a supporting seat and a swing arm arranged on the supporting seat; a spring mechanism is further arranged between the swing arm and the supporting seat, a shoe body is arranged at the end, away from the supporting seat, of the swing arm, the swing arm is connected with the shoe body through a base plate, and the base plate is arranged on the swing arm in a swing mode. In the jumping stroke of the shoe body, the base plate drives the shoe body to swing; the shoe body is arranged on the base plate capable of swinging, when the shoe body jumps, swinging of the base drives the shoe body to swing together, the inclination angle is gradually increased, and in the process that the shoe body is away from the contact rail, one side of the shoe body can basically keep in the state of making contact with the contact rail in the direction perpendicular to the advancing direction of a subway.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

The utility model provides an all-solid-state battery capable of preventing short circuit, and belongs to the technical field of all-solid-state batteries. The all-solid-state battery comprises a solid electrolyte layer, a positive electrode and a negative electrode, the positive electrode and the negative electrode are alternately stacked, the solid electrolyte layer is arranged between the positive electrode and the negative electrode, an insulating layer is arranged on a positive electrode current collector on the side where a tab is located and on the periphery of a positive electrode material area on the opposite side, and insulating tapes are pasted on the upper and lower sides of the positive electrode without the insulating layer. According to the utility model, the gluing ion / electronic insulating layers are arranged at the peripheries of the lugs and the opposite sides of the lugs in the positive electrode material area, and the insulating tapes are adhered to the upper and lower surfaces of the two sides of the positive electrode without the insulating layers, so that short circuit caused by shearing of the edges of the positive and negative electrode pieces under high voltage can be effectively prevented, and the safety and the reliability of the battery are improved.

The invention discloses a modified zinc negative electrode and an aqueous zinc ion battery comprising the same, the modified zinc negative electrode comprises a negative electrode current collector, at least one surface of the negative electrode current collector is provided with a modified coating, and the modified coating comprises a rare earth-based metal organic framework material and a binder. In the modified coating, the rare earth-based metal organic framework material changes the microstructure of the zinc negative electrode and homogenizes the surface electric field and ion flow of the zinc negative electrode, so that disordered deposition of zinc ions can be blocked, a uniform transmission channel can be provided for the zinc ions, growth of zinc dendritic crystals and dead zinc accumulation on the surface are inhibited, and the zinc negative electrode has the advantages of high corrosion resistance and high corrosion resistance. And meanwhile, direct contact between the electrolyte and the zinc negative electrode can be effectively avoided, and hydrogen evolution side reaction and electrode corrosion are inhibited, so that the cycle performance of the aqueous zinc battery is improved.

The invention provides a composite electrode for a solid-state battery, a preparation method of the composite electrode, a battery cell for the solid-state battery and the solid-state battery, and particularly relates to the technical field of solid-state batteries. The composite electrode for the solid-state battery comprises a current collector; the active material layer is arranged on at least one side surface of the current collector; the solid electrolyte layer is arranged on the surface of one side, far away from the current collector, of the outer side of the active material layer; the solid electrolyte layer extends outwards in the circumferential direction of the active material layer so as to form a coating structure around the active material layer; and the solid electrolyte layer at the coating structure is in direct contact with the current collector. According to the composite electrode, a solid electrolyte layer structure with edge supporting and insulating effects is formed around the active material layer, so that direct contact between the active material and the edge of the current collector is avoided, and local short circuit is prevented. In addition, the extended solid electrolyte layer can also be used as a physical barrier, so that side reaction of an electrode interface is reduced, the cycle life of the battery is remarkably prolonged, and the safety performance of the battery is remarkably improved.

The invention relates to the technical field of lithium ion batteries, in particular to a halogenated electrolyte modified low-impedance positive electrode and a preparation process and application thereof. The problem that an existing lithium ion battery positive electrode material is high in impedance is solved. According to the preparation method, the carbon-coated aluminum foil is used as the positive current collector, so that the positive current collector has relatively low contact resistance and relatively high adhesion, the charge transfer resistance and the internal resistance of the battery are reduced, and the rate capability and the cycle performance of the battery are improved; a positive active material is added, C6H12O6.H2O is adopted for carbon coating to improve the electron transmission capacity of lithium iron phosphate, titanium-vanadium co-doping synergistically improves the electron conductivity, and the electron conduction impedance is reduced; the halide solid electrolyte coats lithium iron phosphate to inhibit side reaction and reduce interface impedance; carbon nano tube coating inhibits particle aggregation and reduces charge transfer impedance; and the modified conductive agent and the modified binder are added, so that the lithium ion battery has higher cycling stability, electrochemical activity and lower impedance.

The invention belongs to the technical field of battery preparation, and particularly relates to a secondary battery and electric equipment. The secondary battery comprises a negative pole piece, wherein the negative pole piece comprises a negative current collector and a negative active material layer arranged on at least one surface of the negative current collector; the negative active material layer comprises a main body region and a thinned region arranged at the edge of the main body region, and the thickness of the thinned region is smaller than that of the main body region; the negative pole piece further comprises an ionic conductive composite material, the ionic conductive composite material makes contact with the thinned area, and the ionic conductive composite material comprises ionic liquid and at least one of a conductive polymer and a sodium ion manganese-based layered oxide. According to the invention, the ionic conductive composite material is added into the negative electrode plate and is in contact with the thinned region, so that the effect of protecting the electrode plate is achieved, the sodium ion conductivity and capacity of the thinned region can be improved, polarization and negative electrode side potential drop in the circulation process can be slowed down, sodium precipitation and side reaction are inhibited, the loss of active sodium is reduced, and the service life of the battery is prolonged.

The application provides a secondary battery and an electronic device, comprising an electrode assembly, the electrode assembly comprising a first electrode sheet, a second electrode sheet and a separator. The first electrode sheet comprises two outer first electrode sheets and an inner first electrode sheet, the two outer first electrode sheets being respectively located at the outermost two sides of the electrode assembly. The first electrode sheet comprises a first current collector and a first active material layer, the first current collector comprising a first surface and a second surface. At least one outer first electrode sheet is a single-sided first electrode sheet, and the first active material layer arranged on the second surface of the single-sided first electrode sheet is a first material layer. The first surface and the second surface of the inner first electrode sheet are both provided with the first active material layer, and the first active material layers arranged on the first surface and the second surface of the inner first electrode sheet are second material layers. The electrical conductivity of the single-sided first electrode sheet is a S / cm, the electrical conductivity of the inner first electrode sheet is b S / cm, and a<=b. Through the above arrangement, the risk of black spots and lithium precipitation of the outer electrode sheet of the electrode assembly is reduced.

Example embodiments include electrode assemblies and all-solid-state batteries. The electrode assembly includes a first solid electrolyte layer, a positive electrode layer, a second solid electrolyte layer, and a negative electrode layer that are disposed along a radial direction of the electrode assembly. The positive electrode layer includes a positive electrode current collector, a first positive electrode active material layer on a first surface of the positive electrode current collector and in contact with the first solid electrolyte layer. A first width of the first positive electrode active material layer is less than a second width of the first solid electrolyte layer, a first buffer structure adjacent to a first side of the first positive electrode active material layer, and a second buffer structure adjacent to a second side of the first positive electrode active material layer.

The invention provides a positive pole piece, a solid-state battery and a preparation method of the positive pole piece, and belongs to the technical field of secondary batteries, and the positive pole piece comprises a positive current collector and a positive active material layer. Wherein the positive electrode active material layer is arranged on the positive electrode current collector, the interface layer is arranged on the positive electrode active material layer, the interface layer comprises a first polymer, and the first polymer comprises polyether sulfonate. According to the positive pole piece provided by the invention, the polymer interface layer formed by cross-linking polyether sulfonate is arranged on the surface of the positive active material layer, so that the interface contact and ion transmission efficiency between the positive pole piece and the solid electrolyte membrane are effectively improved based on good ionic conductivity, chemical stability and mechanical flexibility of the interface layer; the interface impedance between the positive pole piece and the solid electrolyte membrane is reduced, and the side reaction of a contact interface is inhibited, so that the rate capability and the cycle life of the solid-state battery are effectively improved.

A battery comprising at least one current collector including a first surface and a second surface opposite the first surface, where the at least one current collector is characterized by a longitudinal body section and a lateral body section extending from the longitudinal body section, a first active material positioned on the first surface on the longitudinal body section, and a second active material positioned on the first surface on the lateral body section.

The application discloses a battery current collector coating device, which comprises a frame, a conversion mechanism, a pole piece, a cylinder, a cylinder rod, a transfer box, a suction pump, a material storage mechanism, a sliding cylinder, a sliding pipe, a guide block, a guide groove, a spring and a spray channel. The frame is provided with the conversion mechanism, the conversion mechanism is provided with the pole piece, the frame is fixedly provided with the cylinder, the cylinder rod of the cylinder is in sliding connection with the frame, the cylinder rod is welded with the transfer box, the transfer box is in contact with the frame, the frame is fixedly provided with the suction pump, the suction pump is connected with the transfer box through a hose, the frame is provided with the material storage mechanism, the sliding cylinder is welded on the transfer box, the sliding pipe is in sliding connection in the sliding cylinder, the spring is arranged in the sliding cylinder, and the sliding pipe is provided with the spray channel at the tail end. The application relates to a battery current collector coating device and a coating process thereof, and has the characteristics that tailing phenomenon is not easy to occur during pole piece coating and the pole piece coating is more uniform.

The invention relates to the technical field of batteries, and provides a negative electrode piece, a secondary battery and an electric device, the negative electrode piece comprises a negative electrode current collector, a first negative electrode film layer and a second negative electrode film layer, the first negative electrode film layer is arranged on at least one surface of the negative electrode current collector, and the second negative electrode film layer is arranged on at least one surface of the negative electrode current collector; the second negative electrode film layer is arranged on the surface, far away from the negative electrode current collector, of the first negative electrode film layer; the first negative electrode film layer contains a first silicon carbon material and first graphite, the second negative electrode film layer contains a second silicon carbon material and second graphite, and the Dv50 particle size of the first silicon carbon material is larger than that of the second silicon carbon material. By adopting the double-layer coating design, the dynamic performance of the small-particle-size silicon-carbon material can be fully played, so that the fast-charging performance of the battery is improved, the side reaction of the large-particle-size silicon-carbon material and electrolyte can be reduced, the irreversible consumption of active ions is reduced, and the service life of the battery is prolonged. And the negative pole piece with good cycle performance, long storage life, high energy density and good fast charging performance is obtained.

The invention relates to the technical field of batteries, in particular to a positive pole piece and a preparation method and application thereof. The positive pole piece comprises a positive current collector; the first positive electrode coating is arranged on the surface of at least one side of the positive electrode current collector, the first positive electrode coating comprises a first active material, and the first active material comprises one or more of lithium iron phosphate, titanium-doped lithium iron phosphate, manganese-doped lithium iron phosphate and magnesium-doped lithium iron phosphate; the second positive electrode coating is arranged on the surface, far away from the positive electrode current collector, of the first positive electrode coating, the second positive electrode coating comprises a second active material, and the second active material comprises nickel cobalt lithium manganate; the solid electrolyte layer is arranged on the surface, far away from the first positive electrode coating, of the second positive electrode coating, and the solid electrolyte layer comprises titanium niobate. The positive pole piece provided by the invention not only has relatively high gram capacity, but also can improve the energy density of the battery, meanwhile, ensures good safety performance, and has a good commercial application prospect.

The invention relates to a foil rolling device and method, a current collector, a pole piece forming method, a battery production system and a power utilization device.In the rolling process, a rolling mechanism is used for rolling a foil to the needed thickness, and then a rolling mechanism is used for rolling a first blank area of the foil in the tape conveying direction; and the first blank area has extension deformation in the tape conveying direction. The first blank area of the foil corresponds to the tab area of the pole piece, so that the tab area of the pole piece is equivalently extended in advance and has extension deformation quantity in advance during cold press molding of the pole piece, and the probability of wrinkling of a coating area due to excessive extension can be reduced. Besides, the calendaring of the tab area is advanced to the rolling process, and the calendaring mechanism is arranged at the downstream end of the rolling mechanism, so that heat generated in the rolling process can be fully utilized in the calendaring process, and the first blank area of the foil is easy to extend.

The invention discloses a negative pole piece, an electrochemical device and electronic equipment. The negative pole piece (100) comprises a negative current collector (101), a first film layer (110) and a second film layer (120). The first film layer (110) comprises a first negative electrode active material, and the first negative electrode active material is graphite; the second film layer (120) comprises a second negative electrode active material, and the second negative electrode active material comprises a silicon carbon material; relative to the second film layer (120), the first film layer (110) is close to the surface of the negative electrode current collector (101). The mass percentage content of the Si element in the second film layer (120) is W1; a plurality of strip-shaped grooves (122) are formed along the surface of the second film layer (120); the ratio of the width of the groove (122) to the width of the groove interval (121) is K, and K is larger than or equal to 0.2 and smaller than or equal to 0.6; k and W1 satisfy 2.4 < = K / W1 < = 4.

Battery cell comprising a housing, an electrolyte and an electrode arrangement, wherein the housing comprises a housing body and an end cap, wherein the housing body accommodates the electrolyte and the electrode arrangement, and the housing body has an opening, wherein the end cap closes the opening. wherein the electrode arrangement comprises a positive electrode sheet, a negative electrode sheet and a separator, the separator being located between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector along the thickness direction of the positive electrode sheet and containing a positive electrode active material, the positive electrode active material comprising a lithium-containing phosphate with an olivine structure, and the negative electrode sheet comprising a negative electrode current collector and a negative electrode film layer arranged on at least one side of the negative electrode current collector along the thickness direction of the negative electrode sheet and containing a negative electrode active material, wherein The discharge capacity of the positive electrode film layer per unit area is 2.0 mAh / cm². 2 up to 3.7 mAh / cm 2 amounts; The size of the positive electrode film layer along a first direction is 75 mm to 105 mm, the first direction being parallel to a direction pointing from the housing body to the end cover.