Abstract: A secondary battery includes a positive electrode plate. that includes a positive current collector, a first positive active material layer distributed on one side of the positive current collector, and a second positive active material layer distributed on an other side of the positive current collector and a negative electrode plate that includes a negative current collector, a first negative active material layer distributed on one side of the negative current collector and opposite to the second positive active material layer, and a second negative active material layer distributed on an other side of the negative current collector. A resistance of the first positive active material layer is R1, a resistance of the second positive active material layer is R2, a resistance of the first negative active material layer is R3, a resistance of the second negative active material layer is R4.

Abstract: A charge method includes obtaining a temperature of a battery, and in response to the temperature of the battery being lower than a preset temperature threshold, determining to use a first charge current to charge the battery until the battery meets a preset condition, and then determining to use a second charge current to charge the battery. The first charge current is used for heating the battery during charging, and the first charge current is greater than the second charge current.

Abstract: This application discloses a battery unit. The battery unit includes a housing, at least one cell, and a buffer. The at least one cell is accommodated in the housing, the buffer is disposed corresponding to a side wall of the cell, and the buffer is provided with an accommodating cavity. A periphery of the accommodating cavity includes at least one packaging structure, the packaging structure includes at least one level of packaging region with a predetermined length. When pressure in the accommodating cavity exceeds packaging strength of the packaging structure, the packaging region is opened to form a buffer space that communicates with the accommodating cavity, reducing influence caused by swelling of the cell.

Abstract: Provided are a secondary battery which includes a positive electrode sheet, a negative electrode sheet, and a separator placed between the positive electrode sheet and the negative electrode sheet. In some embodiments, the positive electrode sheet includes a positive electrode current collector and positive film layers A1 and B1 respectively provided on two surfaces of the positive electrode current collector, and the negative electrode sheet includes a negative electrode current collector and negative film layers respectively provided on two surfaces of the negative electrode current collector, where capacities per unit area Cap A1 and Cap B1 of the positive film layers A1 and B1 satisfy Cap A1<Cap B1, and the negative electrode current collector of the negative electrode sheet is provided with at least one through hole.

Abstract: An electrode assembly includes a first electrode sheet, a second electrode sheet, and a first separator. The first electrode sheet and second electrode sheet are of opposite polarities, the first separator is configured to separate the first electrode sheet and the second electrode sheet. The first electrode sheet, the second electrode sheet, and the first separator are wound in a winding direction. The electrode assembly has a bending region. The bending region is provided with a second separator that is laminated with the first separator and configured to separate the first electrode sheet and the second electrode sheet adjacent to each other. At least part of ions deintercalated from the first electrode sheet are able to pass through the first separator and the second separator and be intercalated in the second electrode sheet.

Abstract: The present application relates to a battery module, comprising a first type of battery cells and a second type of battery cells electrically connected at least in series, wherein the first type of battery cells and the second type of battery cells are battery cells with different chemical systems, the first type of battery cells comprises N first battery cells, the second type of battery cells comprises M second battery cells, N and M are positive integers, the first battery cell comprises a first separator and a first electrolyte, the second battery cell comprises a second separator and a second electrolyte, a kinetic characteristic factor x1 of the first battery cell is: x1=1000×(?1×r1)/(?1×t1×?1), a kinetic characteristic factor x2 of the second battery cell is: x2=1000×(?2×r2)/(?2×t2×?2), and x1 and x2 satisfy: 0.01?x1/x2?160.

Abstract: A secondary battery and a preparation method thereof, and a battery module, battery pack, and apparatus containing a secondary battery are provided. In some embodiments, the secondary battery includes a positive electrode plate, a negative electrode plate, and an electrolyte, where the positive electrode plate includes a positive electrode current collector and a positive electrode film layer that is disposed on at least one surface of the positive electrode current collector and that includes a positive electrode active material, and the negative electrode plate includes a negative electrode current collector and a negative electrode film layer that is disposed on at least one surface of the negative electrode current collector and that includes a negative electrode active material; and the positive electrode active material includes a first material and a second material.

Abstract: An electrode assembly, secondary battery, battery module, battery pack and electrical device are provided. In some embodiments, the electrode assembly comprises a positive electrode plate, a negative electrode plate and a separator disposed between the positive electrode plate and the negative electrode plate, the positive electrode plate satisfies CAP1=CAP2, in which CAP1 represents capacity of the first positive electrode film layer in Ah, CAP2 represents capacity of the second positive electrode film layer in Ah, and the electrode assembly satisfies |R4/R3-R2/R1|>0, in which R1 represents resistance of the first positive electrode film layer in ?, R2 represents resistance of the second positive electrode film layer in ?, R3 represents resistance of the first negative electrode film layer in m? and R4 represents resistance of the second negative film layer in m?. The present applicant may extend the cycle life of the secondary battery.

Abstract: A hybrid series battery module includes a first-type battery cell including a first negative electrode plate and a second-type battery cell including a second negative electrode plate. Energy density of the first-type battery cell is less than energy density of the second-type battery cell. A first interlayer spacing of a negative electrode active material of the first negative electrode plate is greater than a second interlayer spacing of a negative electrode active material of the second negative electrode plate. In a state of charge of 0%, a ratio of the first interlayer spacing to the second interlayer spacing falls within a range of greater than or equal to 1.005 and less than or equal to 1.600.

Abstract: The present application provides a battery pack and a power consuming device powered by the battery pack. The battery pack includes a battery pack cavity and a plurality of battery cells received in the battery pack cavity. An interior space of the battery pack cavity can be divided into a first region with a temperature change rate of K1 and a second region with a temperature change rate of K2, where 0.066?K1?0.131 and 0.034?K2?0.066, K1 and K2 being expressed in ° C./min. The plurality of battery cells include at least one first battery cell arranged in the first region, and at least one second battery cell arranged in the second region. The battery pack of the present application can reduce or avoid the cask effect at low temperature and improve the energy retention rate at low temperature.

Abstract: A secondary battery and a preparation method thereof and a battery module, a battery pack and a device comprising the secondary battery are provided. The secondary battery comprises an electrode assembly, which comprises a main body part and a tab extending from the main body part, which comprises a negative electrode plate, and the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode film layer comprises a first region and second regions provided on both sides of the first region in the extension direction of the tab, the first region comprises a first negative electrode active material, the first negative electrode active material comprising artificial graphite, and each of the second regions comprises a second negative electrode active material, the second negative electrode active material comprising graphite.

Abstract: A battery module includes one or more first battery cells and one or more second battery cells. A first number a of the one or more first battery cells is greater than or equal to a second number b of the one or more second battery cells. A first product X1 of a first volumetric energy density E1 and a first thickness T1 of each of the one or more first battery cells and a second product X2 of a second volumetric energy density E2 and a second thickness T2 of each of the one or more second battery cells satisfy. 0.35?X1/X2?18.

Abstract: A control method of a battery apparatus includes acquiring a state parameter of a first battery module of the battery apparatus, controlling the first battery module and a charging device to form a first charging loop in response to the state parameter of the first battery module being less than a preset threshold, and controlling the first battery module, a second battery module of the battery apparatus, and the charging device to be connected in series to form a second charging loop in response to the state parameter of the first battery module being greater than or equal to the preset threshold. A charging rate of the first charging loop is higher than a charging rate of the second charging loop.

Abstract: A hybrid series battery module includes a first-type battery cell including a first negative electrode plate and a second-type battery cell including a second negative electrode plate. Energy density of the first-type battery cell is less than energy density of the second-type battery cell. A first interlayer spacing of a negative electrode active material of the first negative electrode plate is greater than a second interlayer spacing of a negative electrode active material of the second negative electrode plate. In a state of charge of 0%, a ratio of the first interlayer spacing to the second interlayer spacing falls within a range of greater than or equal to 1.005 and less than or equal to 1.600.

Abstract: The present application relates to a battery module, comprising a first type of battery cells and a second type of battery cells electrically connected at least in series, wherein the first and second type of battery cells are battery cells of different chemical systems, the first type of battery cells comprises N first battery cells, the second type of battery cells comprises M second battery cells, and N and M are positive integers; a positive electrode plate of the second battery cell contains two or more positive electrode active materials, and when a dynamic SOC of the second battery cell is in a range from 90% to 98%, a change rate ?OCV/?SOC in an OCV relative to the SOC of the second battery cell satisfies 3??OCV/?SOC?9, in mV/% SOC, where SOC represents a charge state and OCV represents an open circuit voltage.

Abstract: A battery unit may comprise a first cell type and a second cell type electrically connected at least in series, wherein the first cell type may include N first cells, the second cell type may include M second cells, and N and M are positive integers; the first cell may have a discharge cell balance rate of CB1, the second cell may have a discharge cell balance rate of CB2, with 0.5?CB1?CB2?1.4, and when the battery unit is charged to 95%-100% of the state of charge, the first cell may have a corresponding open-circuit voltage change rate of not greater than 0.005 V/% SOC, and the second cell type may have a corresponding open-circuit voltage change rate greater than that of the first cell.

Abstract: A positive electrode active material comprising an A material and a B material, wherein the A material is at least one selected from the following single crystal materials or single crystal-like materials: LixMy(PO4)z, wherein M is selected from one or more of Ni, Co, Mn, Fe, Mg, Al, V, Zn, Zr, and F, v is the valence of M, 1?x?3, 1?z?3, and x+vy-3z=0; the A material has a Dv50 of 0.8 µm to 4.2 µm; the B material is selected from at least one of the following materials: (i) LiAO2, wherein A is Ni, Co or Mn; or (ii) LiNiaCobE1-a-bO2, wherein E is selected from at least one of Mn and Al, 0.50?a?0.98, and 0.001?b?0.3; wherein based on the total weight of the positive electrode active material, the A material is present in a mixing ratio m of 50 wt% to 97 wt%.

Abstract: The present application provides a battery cell, including a cover plate, a housing, and a gas-permeable film. The housing has an opening, and the cover plate covers the opening of the housing. The cover plate and/or housing have/has at least one through hole, and the inside and the outside of the battery cell are in communication with each other via the through hole; and the gas-permeable film is connected to the inside of the cover plate and/or housing and covers the at least one through hole. According to the battery cell of the present application, gas inside a battery can be discharged to prevent the gas from accumulating inside the housing, thereby improving performance of an electrode assembly, prolonging service life of a secondary battery, and ensuring safety performance of the battery cell.

Abstract: A battery pack may include a first battery cell type and a second battery cell type, wherein the first battery cell type may include n first battery cells, and the second battery cell type may include m second battery cells, with n and m being each independently selected from an integer of 1 or more, wherein the second battery cell may have a discharge power at ?20° C. greater than that of the first battery cell, the difference in discharge power at ?20° C. between the second battery cells and the first battery cells being ?10 W; the percentage by number of the first battery cells in the battery cells comprised in area A may be 20% to 100%, and the percentage by number of the second battery cells in the battery cells comprised in the area B may be 5% to 100%.

Abstract: A battery unit may comprise a first cell type and a second cell type electrically connected at least in series, wherein the first cell type may include N first cells, the second cell type may include M second cells, and N and M are positive integers; the first cell may have a discharge cell balance rate of CB1, the second cell may have a discharge cell balance rate of CB2, with 0.5?CB1?CB2?1.4, and when the battery unit is charged to 95%-100% of the state of charge, the first cell may have a corresponding open-circuit voltage change rate of not greater than 0.005 V/% SOC, and the second cell type may have a corresponding open-circuit voltage change rate greater than that of the first cell.