Battery and electric device

Abstract

Embodiments of the present application provide a battery and an electric device. The battery comprises a case, battery cells, and heat exchange members. The battery cells are accommodated in the case. Each battery cell comprises a casing and an electrode assembly accommodated in the casing, and the casing comprises two first side walls which are provided opposite to each other in the thickness direction of the battery cell. The heat exchange members are arranged on at least one side of the battery cells in the thickness direction and are used for exchanging heat with the first side walls. Each electrode assembly comprises a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer provided on at least one side of the positive electrode current collector; the positive electrode film layer comprises a positive electrode active material; and the positive electrode active material comprises lithium-containing phosphate having an olivine structure. The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer provided on at least one side of the negative electrode current collector; the negative electrode film layer comprises a negative electrode active material; and the negative electrode active material comprises a carbon-based material.

Description

Battery and power consuming device TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and more particularly, to a battery and a power consuming device. BACKGROUND

[0002] Batteries are widely used in electronic devices, such as mobile phones, notebook computers, electric cars, electric vehicles, electric aircraft, electric ships, electric toy cars, electric toy ships, electric toy aircraft, electric tools, and the like.

[0003] In the development of battery technology, how to improve the cycle performance of the battery is a research direction in the field of battery technology.

[0004] SUMMARY

[0005] The present application provides a battery and a power consuming device, which can improve the cycle performance of the battery.

[0006] In a first aspect, the embodiments of the present application provide a battery, which includes a box body, a battery monomer, and a heat exchange member. The battery monomer is accommodated in the box body, and the battery monomer includes a shell and an electrode assembly accommodated in the shell, and the shell includes two first side walls oppositely arranged along the thickness direction of the battery monomer. The heat exchange member is arranged on at least one side of the battery monomer along the thickness direction and is used for heat exchange with the first side wall. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator film between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material. The positive electrode active material includes a lithium-containing phosphate with an olivine structure. The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one side of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material. The negative electrode active material includes a carbon-based material.

[0007] The first side wall can be the largest shell wall of the shell. The heat exchange between the first side wall and the heat exchange member can improve the heat exchange efficiency, thereby reducing the temperature rise of the battery monomer during fast charging, improving the cycle performance and cycle life of the battery monomer, reducing the risk of thermal runaway, and improving the reliability. The carbon-based material and the lithium-containing phosphate have high cycle stability. The use of the lithium-containing phosphate as the positive electrode active material and the use of the carbon-based material as the negative electrode active material can improve the cycle decay of the battery monomer caused by the temperature rise during fast charging, and improve the cycle performance of the battery monomer. The embodiments of the present application use the carbon-based material and the lithium-containing phosphate as the negative electrode active material and the positive electrode active material respectively, and combine the heat exchange between the first side wall and the heat exchange member, which can improve the fast charging capability of the battery monomer, reduce the influence of heat generation during fast charging on the cycle performance of the battery monomer, save the charging time, and improve the user experience.

[0008] In some embodiments, the charging time of the battery cell from 10% SOC to 80% SOC under room temperature conditions is 5 minutes to 10.5 minutes. The battery cell has a fast charging capability, which can save charging time and improve user experience. During the fast charging process of the battery cell, the heat exchange member can exchange heat with the first side wall to reduce the temperature rise of the battery cell during the fast charging process; the cycle stability of the carbon-based material and the lithium-containing phosphate is high, which can improve the cycle decay of the battery cell caused by the temperature rise process during the fast charging process.

[0009] In some embodiments, a first side wall of the battery cell is connected with the heat exchange member. The cycle stability of the lithium-containing phosphate with an olivine structure is relatively excellent, and the use of the lithium-containing phosphate with an olivine structure can reduce the heat generation of the battery cell during the fast charging process and reduce the risk of thermal runaway of the battery cell. The use of the lithium-containing phosphate with an olivine structure can reduce the heat exchange demand, and the embodiment of the application connects the first side wall of one side of the battery cell with the heat exchange member, which can reduce the number of heat exchange members, save space, and improve the energy density of the battery.

[0010] In some embodiments, the battery includes a plurality of battery cell groups and a plurality of heat exchange members, the plurality of battery cell groups are arranged along the thickness direction, and each battery cell group includes at least two battery cells arranged along a direction perpendicular to the thickness direction. One heat exchange member is arranged between every two battery cell groups. One heat exchange member can exchange heat with the battery cells of two battery cell groups at the same time, which can reduce the number of heat exchange members, improve the space utilization and energy density of the battery.

[0011] In some embodiments, the heat exchange member is bonded to the first side wall through a first adhesive layer. The first adhesive layer can stably connect the heat exchange member with the first side wall to improve the stability of heat exchange between the heat exchange member and the battery cell.

[0012] In some embodiments, the heat exchange member includes a heat conduction plate, and a flow channel is arranged inside the heat conduction plate, and the flow channel is used to arrange a heat exchange medium. The flow channel can guide the flow of the heat exchange medium, so that the heat exchange medium exchanges heat with the battery cell when flowing through the heat conduction plate.

[0013] In some embodiments, the heat exchange member further includes an insulating layer, and at least part of the insulating layer is arranged between the heat conduction plate and the first side wall. The insulating layer can insulate the heat conduction plate from the first side wall, increase the creepage distance between the heat conduction plate and the first side wall, and reduce the risk of short circuit.

[0014] In some embodiments, the thermal conductivity of the insulating layer is greater than or equal to 0.1 W / (m·K). The insulating layer has good heat conduction capacity, thereby improving the heat exchange efficiency.

[0015] In some embodiments, the housing further comprises a first end wall and a second end wall arranged oppositely, and the first side wall connects the first end wall and the second end wall. The first end wall is located at the lower side of the electrode assembly, and the second end wall is located at the upper side of the electrode assembly and connected to the box body. Fixing the second end wall to the box body can save the space at the upper side of the battery monomer and improve the space utilization.

[0016] In some embodiments, the second end wall is bonded to the box body, thereby improving the stability of the battery.

[0017] In some embodiments, the battery monomer further comprises a pressure relief mechanism arranged at the first end wall. During the rapid charging of the battery, even if the battery monomer is accidentally in thermal runaway, the high-temperature substances generated by the battery monomer can be sprayed downward through the pressure relief mechanism, thereby reducing the thermal impact on the upper side of the battery, reducing the risk of user injury, and improving the reliability of the battery and the electric device using the battery.

[0018] In some embodiments, the housing further comprises a first end wall connected to the two first side walls. The battery monomer further comprises a first electrode terminal arranged at the first end wall; and the electrode assembly comprises an electrode main body and a first tab led out from the electrode main body, and the first electrode terminal is electrically connected to the first tab. Arranging the first electrode terminal at the first end wall can reduce the risk of interference between the first electrode terminal and the heat exchange member, and improve the heat exchange efficiency.

[0019] In some embodiments, the area of the orthographic projection of the part of the first electrode terminal located outside the first end wall on the first end wall is 200mm 2 -600mm 2 . The part of the first electrode terminal located outside the first end wall has a larger area, which can increase the overcurrent area, reduce heat generation, reduce the temperature rise of the first electrode terminal during the battery cycle, and improve the reliability. The first electrode terminal has a larger exposed area, which can increase the heat dissipation efficiency of the first electrode terminal.

[0020] In some embodiments, the first end wall has an inner surface facing the electrode assembly, and the first electrode terminal does not exceed the inner surface in the direction close to the electrode assembly. The first electrode terminal can not occupy the internal space of the housing, thereby improving the space utilization of the battery monomer and improving the energy density of the battery monomer.

[0021] In some embodiments, the first electrode terminal comprises a connecting portion provided with a through hole, and the first tab is arranged in the through hole, and a part of the first tab is located on the side of the connecting portion away from the electrode main body and connected to the connecting portion. By arranging the through hole, the first tab can be led out to the outside of the connecting portion, thereby reducing the distance between the connecting portion and the electrode main body, improving the internal space utilization of the battery monomer, and improving the energy density of the battery monomer.

[0022] In some embodiments, the first electrode terminal includes a terminal body and a cover plate, the terminal body is fixed to the first end wall, the terminal body is provided with a recess on a side away from the electrode body, and a bottom wall of the recess is a connecting portion. The cover plate is arranged on a side of the connecting portion away from the electrode body and is used for covering the recess. The recess can accommodate a part of the first tab, thereby improving the space utilization. The cover plate separates the external space of the shell from the through hole, thereby achieving sealing and reducing the risk of electrolyte leakage.

[0023] In some embodiments, at least part of the cover plate is accommodated in the recess. By accommodating the cover plate in the recess, the space utilization can be improved.

[0024] In some embodiments, in the width direction of the first end wall, the size of the first end wall is W1 mm, and the size of the part of the first electrode terminal outside the first end wall is W2 mm. W2 and W1 satisfy: 0.4≤W2 / W1≤1.

[0025] By setting W2 / W1 to be greater than or equal to 0.4, the first electrode terminal can have a larger exposed area, the connection area between the first electrode terminal and the busbar component can be increased, the overcurrent capacity can be improved, the temperature rise can be reduced, the cycle performance of the battery can be improved, and the reliability of the battery can be improved. By limiting W2 / W1 to be less than or equal to 1, the space occupied by the first electrode terminal in the width direction can be reduced, and the space utilization can be improved.

[0026] In some embodiments, the box body includes a first box wall on the upper side of the battery monomer, and the battery monomer is fixed to the first box wall. The embodiments of the present application can save the space on the upper side of the battery monomer and improve the space utilization.

[0027] In some embodiments, the first box wall is used as at least part of the floor of the vehicle. By using the first box wall as the floor, the parts of the vehicle can be saved, the integration of the vehicle can be improved, and the assembly process of the vehicle can be simplified.

[0028] In some embodiments, the battery further includes a mounting beam arranged on a side of the first box wall away from the battery monomer, which can improve the overall strength of the battery. The mounting beam can also provide mounting positions for some components of the electric device, thereby reducing the parts, improving the integration, and simplifying the assembly process.

[0029] In some embodiments, the mounting beam is used for mounting the seat of the vehicle. By combining the mounting beam for mounting the seat with the first box wall, the overall utilization of the vehicle can be improved.

[0030] In some embodiments, the box body includes a second box wall arranged on the lower side of the battery monomer. The second box wall can protect the battery monomer from the outside to reduce the risk of the battery monomer being impacted by external impurities and improve the reliability of the battery.

[0031] In some embodiments, the second tank wall is spaced apart from the battery cell. When the battery cell is in thermal runaway, the space between the second tank wall and the battery cell can serve as a discharge channel, thereby timely discharging the substances released by the battery cell to the outside of the tank, reducing the risk of battery explosion. When the second tank wall is subjected to external impact, the space between the second tank wall and the battery cell can act as a barrier, reducing the impact force transmitted to the battery cell, reducing the risk of battery cell failure, and improving the reliability of the battery.

[0032] In some embodiments, the battery further comprises a support disposed on the lower side of the shell and used to support the shell. The support can support the battery cell, thereby improving the stability of the battery cell and enhancing the overall structural strength of the battery.

[0033] In some embodiments, the tank comprises a second tank wall disposed on the lower side of the battery cell. The support is bonded to the shell and the second tank wall. The support connects the battery cell and the second tank wall, thereby enhancing the overall structural strength of the battery.

[0034] In some embodiments, the elastic modulus of the support is less than the elastic modulus of the second tank wall. The elastic modulus of the support is smaller, and when the second tank wall is subjected to external impact, the support can deform to reduce the acting force transmitted to the battery cell, thereby reducing the risk of battery cell failure.

[0035] In some embodiments, the tank comprises a plurality of limiting beams spaced apart along the thickness direction of the battery cell, and a plurality of battery cells are arranged between adjacent limiting beams. The support connects adjacent limiting beams.

[0036] The limiting beam has high deformation resistance and can effectively constrain the battery cell in the thickness direction; the support can provide a restraining force to the limiting beam, thereby reducing the deformation of the limiting beam and limiting the expansion of the battery cell, improving the cycle performance of the battery cell, and reducing the risk of tank cracking.

[0037] In some embodiments, the support comprises a metal strip and an insulating film covering the metal strip, and the insulating film separates the metal strip from the first end wall. The metal strip has high strength and can effectively support the battery cell and constrain the limiting beam. The insulating film can insulate and isolate the metal strip from the battery cell, thereby reducing the risk of short circuit.

[0038] In some embodiments, the support has a cavity inside. By providing a cavity, the weight of the support can be reduced.

[0039] In some embodiments, the battery cell further comprises a sampling member disposed on the shell, and the sampling member is used to sample the temperature of the shell. The sampling member can sample the temperature of the shell in real time, thereby facilitating the monitoring and adjustment of the temperature of the battery cell, reducing the risk of abnormal temperature rise of the battery cell during rapid charging, and improving the reliability of the battery.

[0040] In some embodiments, the expansion pressure of the battery cell in the thickness direction of the battery cell is 0.5 MPa-2.4 MPa. The expansion pressure of the battery cell in the thickness direction is limited to 0.5 MPa-2.4 MPa to reduce the expansion deformation of the battery cell during rapid charging, improve the cycle performance of the battery cell, reduce the risk of cracking of the box body, and improve the reliability of the battery.

[0041] In some embodiments, the battery includes a plurality of battery cells and a plurality of busbar components electrically connecting the plurality of battery cells. The plurality of busbar components includes at least one first busbar component, the first busbar component including a first busbar layer and a second busbar layer stacked and connected, the first busbar layer electrically connecting at least two battery cells arranged in the thickness direction.

[0042] The first busbar component has at least a double-layer structure, and the first busbar layer and the second busbar layer of the first busbar component can both transmit current, so that the first busbar component has a higher current-carrying area, thereby reducing the heat generation of the first busbar component, improving the rapid charging capability of the battery, and reducing the risk of thermal runaway. Under the premise that the current-carrying area meets the requirements, the first busbar component is set to a double-layer structure, which can reduce the requirement for the thickness of the first busbar layer. The battery cell will expand during the cycle, thereby stretching the first busbar layer. The first busbar layer has a smaller thickness, which is easy to deform to adapt to the deformation of the battery cell, reduces the risk of the connection between the battery cell and the first busbar layer being pulled apart, and improves the reliability of the battery.

[0043] In some embodiments, the first busbar component includes at least one bending portion connecting the first busbar layer and the second busbar layer. The bending portion can connect the first busbar layer and the second busbar layer and transmit current between the first busbar layer and the second busbar layer, thereby improving the current-carrying capability of the first busbar component.

[0044] In some embodiments, the first busbar layer includes a first busbar portion, a second busbar portion, and a first buffer portion connecting the first busbar portion and the second busbar portion, the first busbar portion and the second busbar portion being arranged in the thickness direction and connected to different battery cells. The second busbar layer includes a first stacking portion, a second stacking portion, and a second buffer portion, the first stacking portion being stacked with the first busbar portion and connected through at least one bending portion, and the second stacking portion being stacked with the second busbar portion and connected through at least one bending portion.

[0045] In the circulation process of the battery, part of the current can be transmitted between the first busbar and the second busbar through the first laminated part, the second buffer part and the second laminated part, a plurality of conductive paths are formed between the first busbar and the second busbar, thereby improving the overcurrent capacity. In the circulation process of the battery cell, the battery cell expands and exerts a pulling force on the first busbar layer; both the first buffer part and the second buffer part can release stress by deformation, thereby reducing the risk of connection failure of the first busbar layer and the battery cell.

[0046] In some embodiments, the box body comprises a plurality of limiting beams, the plurality of limiting beams are arranged at intervals along the thickness direction of the battery cell, and a plurality of battery cells are arranged between adjacent limiting beams. In the thickness direction, the distance between the two adjacent limiting beams is D1, and the sum of the sizes of all the electrode assemblies stacked between the two adjacent limiting beams in the thickness direction is D2. 85%≤D2 / D1≤92%.

[0047] D2 / D1 is limited to be less than or equal to 92% to reduce the expansion pressure of the battery cell, reduce the deformation of the battery cell during rapid charging, reduce the risk of cracking of the box body, and improve the reliability of the battery; D2 / D1 is limited to be greater than or equal to 85% to improve the space utilization in the thickness direction and improve the energy density of the battery. D2 / D1 is limited to 85%-92%, which can balance the expansion pressure of the battery cell and the energy density of the battery to a certain extent.

[0048] In some embodiments, the single-sided coating weight of the negative electrode film layer is 90 mg / 1540 mm 2 to 170 mg / 1540 mm 2 , and can be 110 mg / 1540 mm 2 to 150 mg / 1540 mm 2 . The single-sided coating weight of the negative electrode film layer is limited in the above range, which can limit the heat generation of the negative electrode sheet per unit area, and reduce the temperature rise of the battery cell, especially during rapid charging.

[0049] In some embodiments, the compaction density of the negative electrode film layer at 100% SOC of the battery cell is 1.15 g / cm 3 to 1.36 g / cm 3 , and can be 1.25 g / cm 3 to 1.36 g / cm 3 . When the compaction density of the negative electrode film layer is in the above range, it is beneficial to improve the energy density of the battery cell; and because the negative electrode active material in the negative electrode film layer is packed more tightly, the contact resistance between particles is smaller, which can reduce the resistance of the negative electrode sheet, thereby reducing heat generation, and is beneficial to improve the rapid charging capacity of the battery.

[0050] In some embodiments, the porosity of the negative electrode sheet is 27%-40%.

[0051] The porosity of the negative electrode sheet is greater than or equal to 27%, which can provide space for impurities generated by side reactions of the negative electrode sheet, slow down the expansion of the negative electrode sheet, reduce the expansion pressure of the battery cell, reduce the deformation of the battery cell, improve the cycle performance of the battery cell, and improve the reliability of the battery cell during fast charging. The porosity of the negative electrode sheet is less than or equal to 40%, which can balance the energy density of the battery cell.

[0052] In some embodiments, the carbon-based material includes at least one of artificial graphite and natural graphite. Artificial graphite and natural graphite have good conductivity, which can reduce heat generation of the negative electrode sheet during charging and improve the fast charging performance of the battery cell.

[0053] In some embodiments, the negative active material further includes a silicon-based material, and the mass content of silicon in the negative active material is 0.3%-10%, which can be 1%-6%.

[0054] The introduction of the silicon-based material into the negative electrode sheet can not only improve the capacity but also increase the expansion of the negative electrode sheet. Therefore, limiting the mass content of silicon in the negative active material to 0.3%-10% can balance the energy density and expansion of the battery cell to a certain extent, reduce the deformation of the battery cell, and improve the cycle performance and fast charging capability of the battery cell.

[0055] In some embodiments, the silicon-based material includes at least one of a silicon oxide compound and a silicon-carbon composite.

[0056] In some embodiments, the negative film layer includes a first negative film layer and a second negative film layer, and the second negative film layer is arranged between the first negative film layer and the negative current collector. The negative active material includes a first negative active material arranged in the first negative film layer and a second negative active material arranged in the second negative film layer, the first negative active material includes artificial graphite, and the second negative active material includes one or more of artificial graphite, natural graphite, and a silicon-based material.

[0057] The first negative film layer and the second negative film layer can be differentially arranged to balance the expansion and capacity of the negative film layer to a certain extent; double-layer coating can construct the pore difference of the negative film layer, reduce the ion transmission tortuosity, reduce the side reaction, and improve the fast charging performance of the battery cell.

[0058] In some embodiments, the thickness ratio of the first negative film layer to the second negative film layer is 3:7-7:3, which can be 4:6-6:4. By adjusting the thickness ratio of the first negative film layer to the second negative film layer, the gradient pore difference between the upper and lower layers can be further increased, the lithium ion transmission tortuosity can be reduced, and the fast charging capability of the battery cell can be improved.

[0059] In some embodiments, the thickness of the first negative electrode film layer is less than or equal to the thickness of the second negative electrode film layer, which can further improve the rapid charging capability of the battery cell.

[0060] In some embodiments, the volume average particle size Dv50 of the first negative electrode active material is less than or equal to the volume average particle size Dv50 of the negative electrode active material.

[0061] The difference in particle size of the first negative electrode active material and the second negative electrode active material can improve the rapid charging performance of the battery cell. During rapid charging, the overpotential of the first negative electrode film layer is usually high, and the bottleneck of rapid charging is mainly in the first negative electrode film layer. In the embodiments of the present application, the particle size of the first negative electrode active material is relatively small, which can shorten the solid phase transmission path of ions, improve the rapid charging performance, and improve the problem of ion precipitation on the surface layer of the negative electrode sheet. The particle size of the second negative electrode active material is relatively large, which can form larger pores in the second negative electrode film layer. During charging, the pores can absorb expansion, reduce the expansion amount of the negative electrode film layer, and improve the reliability of the battery cell during rapid charging.

[0062] In some embodiments, the volume average particle size Dv50 of the first negative electrode active material is 7.8 μm-14.3 μm, which can be 7.8 μm-11.3 μm.

[0063] The volume average particle size Dv50 of the first negative electrode active material is set to the above range, which can shorten the solid phase transmission path of lithium ions, improve the rapid charging performance, and improve the stability of the material during preparation. On the other hand, the first negative electrode active material with the above volume average particle size range can cooperate with the second negative electrode active material, which is conducive to building a gradient pore difference between the first negative electrode film layer and the second negative electrode film layer, reducing the tortuosity of lithium ion transmission, and improving the rapid charging performance of the battery cell.

[0064] In some embodiments, the volume average particle size Dv50 of the second negative electrode active material is 9.5 μm-18.5 μm, which can be 9.5 μm-14.6 μm. Setting the volume average particle size Dv50 of the second negative electrode active material in the above range can make the pores of the second negative electrode film layer more abundant, which is conducive to improving the rapid charging capability of the battery cell and reducing the expansion of the negative electrode film layer during charging.

[0065] In some embodiments, the specific surface area of the negative electrode active material is 0.5 m 2 / g-3 m 2 / g, which can be 0.6 m 2 / g-1.2 m 2 / g. Limiting the specific surface area of the negative active material to be greater than or equal to 0.5 m 2 / g can improve the ability of the battery monomer to fast charge; limiting the specific surface area of the negative active material to be less than or equal to 3 m 2 / g can reduce the side reaction of the battery monomer during storage and reduce the swelling pressure.

[0066] In some embodiments, the lithium-containing phosphate of olivine structure has a chemical formula of LiFe 1-x-y Mn x M y PO4, 0≤x≤1, 0≤y<1, M is selected from one or more of V, Nb, Ti, Co, Ni, Sc, Ge, Mg, Al, Zr, Mn, Hf, Ta, Mo, W, Ru, Ag, Sn and Pb.

[0067] In some embodiments, the single-sided coating weight of the positive electrode film layer is 200 mg / 1540 mm 2 -370 mg / 1540 / mm 2 ; and can be 240 mg / 1540 mm 2 -330 mg / 1540 mm 2 . Setting the single-sided coating weight of the positive electrode film layer in the above range can limit the heat generation per unit area of the positive electrode sheet, and can take into account the improvement of the energy density and the charge rate performance of the battery monomer.

[0068] In some embodiments, the compaction density of the positive electrode film layer at 100% SOC of the battery monomer is 2.50 g / cm 3 -2.80 g / cm 3 ; and can be 2.55 g / cm 3 -2.70 g / cm 3 . When the compaction density of the positive electrode film layer is in the above range, it is beneficial to improve the energy density of the battery monomer; and since the positive active material in the positive electrode film layer is packed more tightly, the contact resistance between particles is smaller, which can further reduce the resistance of the positive electrode sheet, thereby reducing the heat generation under fast charging.

[0069] In some embodiments, the porosity of the positive electrode sheet is 25%-32%. When the porosity of the positive electrode sheet is greater than or equal to 25%, it can provide space for impurities generated by the side reaction of the positive electrode sheet, reduce the swelling pressure of the battery monomer, reduce the deformation of the battery monomer, and improve the cycle performance of the battery monomer. When the porosity of the positive electrode sheet is less than or equal to 32%, the energy density of the battery monomer can be taken into account to some extent.

[0070] In some embodiments, the thickness of the positive electrode sheet is 0.13 mm-0.2 mm. With the positive electrode sheet having a smaller thickness, the ion migration path can be shortened, the ion migration rate can be improved, the heat generation of the battery cell can be reduced, and the rapid charging performance of the battery cell can be improved.

[0071] In some embodiments, the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer is 0.05-0.3. Limiting the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer to be greater than or equal to 0.05 can improve the current-carrying capacity of the positive electrode current collector, reduce the temperature rise of the positive electrode sheet, and improve the rapid charging performance of the battery cell. Limiting the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer to be less than or equal to 0.3 can reduce the loss of capacity of the positive electrode sheet. The embodiments of the present application limit the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer to be 0.05-0.3, which can balance the rapid charging performance and energy density of the battery cell to a certain extent.

[0072] In some embodiments, the volume average particle size of the positive electrode active material satisfies 1 μm≤Dv50≤2 μm, 0.4 μm≤Dv10≤0.7 μm. The particle size of the positive electrode active material is relatively small, the lithium ion has a shorter lithium extraction path in the positive electrode active material, and the heat generation is less. Moreover, the particle size of the positive electrode active material is not too small, which can reduce agglomeration during the processing and preparation process, and the performance of the positive electrode active material is stable.

[0073] In some embodiments, the battery cell includes an electrolyte contained in the shell. During the charging and discharging of the battery cell, active ions are embedded and extracted between the positive electrode sheet and the negative electrode sheet, and the electrolyte plays a role in conducting active ions between the positive electrode sheet and the negative electrode sheet.

[0074] In some embodiments, the electrical conductivity of the electrolyte at room temperature is 15 mS / cm-20 mS / cm. When the electrical conductivity of the electrolyte is in the above range, the migration rate of ions in the electrolyte is higher, thereby further reducing the internal resistance of the battery cell, reducing heat generation, and improving the rapid charging performance of the battery cell.

[0075] In some embodiments, the electrolyte includes an organic solvent, and the organic solvent includes one or more of a carbonate solvent and a carboxylic acid ester solvent. The combination of the organic solvent can improve the electrical conductivity of the electrolyte, reduce the viscosity, and thereby improve the rapid charging performance of the battery.

[0076] In some embodiments, the carbonate solvent includes one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0077] In some embodiments, the carboxylic acid ester comprises R1-COO-R2, R1 and R2 each independently comprises an alkyl group with 1-5 carbon atoms or a haloalkyl group with 1-5 carbon atoms. The above-mentioned chain carboxylic acid ester solvent has a high conductivity, which is beneficial to improve the rapid charging capability of the battery cell.

[0078] In some embodiments, the electrolyte comprises a lithium salt, the lithium salt comprises lithium bisfluorosulfonylimide LiFSI and lithium hexafluorophosphate LiPF6, the molar concentration of lithium bisfluorosulfonylimide LiFSI is 0.2-0.5 mol / L, and the molar concentration of lithium hexafluorophosphate LiPF6 is 0.5-1.0 mol / L. The above-mentioned lithium salt is easy to dissociate, which is beneficial to the rapid migration of lithium ions; and the electrolyte system is relatively stable and is not easy to decompose, which can improve the cycle performance of the battery cell.

[0079] In some embodiments, the density p of the electrolyte at room temperature satisfies: 1.05 g / mL≤p≤1.35 g / mL. When the density p of the electrolyte is in the above-mentioned range, the migration rate of lithium ions in the electrolyte is higher, which can further reduce the internal resistance of the battery cell, thereby reducing the heat generation, and can improve the rapid charging performance of the battery cell.

[0080] In a second aspect, the embodiments of the present application provide a power utilization device, comprising the battery provided in any of the embodiments of the first aspect, and the battery is used to provide electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0081] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0082] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application;

[0083] FIG. 2 is a schematic diagram of a battery provided by some embodiments of the present application;

[0084] FIG. 3 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application;

[0085] FIG. 4 is an enlarged schematic diagram of the circle frame in FIG. 2;

[0086] FIG. 5 is a partial cross-sectional schematic diagram of a battery provided by some embodiments of the present application;

[0087] FIG. 6 is a cross-sectional schematic diagram of an electrode assembly of a battery cell provided by some embodiments of the present application;

[0088] FIG. 7 is a schematic view of a negative electrode tab of a battery cell according to some embodiments of the present application;

[0089] FIG. 8 is a schematic view of a positive electrode tab of a battery cell according to some embodiments of the present application;

[0090] FIG. 9 is a schematic view of a battery cell according to some embodiments of the present application;

[0091] FIG. 10 is a schematic view of a battery cell according to some embodiments of the present application;

[0092] FIG. 11 is a schematic view of a battery according to some embodiments of the present application;

[0093] FIG. 12 is an enlarged view of the circle in FIG. 11;

[0094] FIG. 13 is a schematic view of a battery according to some embodiments of the present application;

[0095] FIG. 14 is an enlarged view of the square in FIG. 13;

[0096] FIG. 15 is a schematic view of a support member of a battery according to some embodiments of the present application;

[0097] FIG. 16 is a schematic view of a battery cell and a first current collecting member according to some embodiments of the present application;

[0098] FIG. 17 is a schematic view of the first current collecting member of FIG. 16;

[0099] FIG. 18 is an exploded schematic view of a battery according to some embodiments of the present application;

[0100] FIG. 19 is a schematic view of a negative electrode tab of a battery cell according to some embodiments of the present application.

[0101] Reference signs are explained as follows

[0102] 1 vehicle; 2 battery; 3 controller; 4 motor;

[0103] 10 battery cell; 100 battery cell group;

[0104] 11 electrode assembly; 111 positive electrode tab; 1111 positive electrode current collector; 1112 positive electrode film layer; 112 negative electrode tab; 1121 negative electrode current collector; 1122 negative electrode film layer; 11221 first negative electrode film layer; 11222 second negative electrode film layer; 113 separator; 11a electrode main body; 11b first tab; 11c second tab;

[0105] 12, housing; 121, shell; 122, end cover; 1221, outer surface; 1222, inner surface; 1223, electrode lead-out hole; 12a, first end wall; 12b, second end wall; 12c, side wall; 12d, first side wall; 12e, second side wall;

[0106] 13, first electrode terminal; 131, connecting portion; 1311, through hole; 132, terminal body; 133, cover plate; 134, recess;

[0107] 14, second electrode terminal; 15, pressure relief mechanism; 151, weak portion; 152, pressure relief portion; 153, fixing portion; 16, sampling member; 17, first fixing member; 18, second fixing member;

[0108] 20, box body; 21, first box wall; 22, second box wall; 23, frame; 24, limiting beam;

[0109] 30, heat exchange member; 31, heat conducting plate; 311, flow channel; 32, insulation layer;

[0110] 40, first adhesive layer; 41, second adhesive layer; 42, third adhesive layer; 43, insulation pad;

[0111] 50, connecting pipe group;

[0112] 60, support member; 61, metal strip; 62, insulation film; 63, cavity;

[0113] 70, first busbar component; 71, first busbar layer; 711, first busbar portion; 712, second busbar portion; 713, first buffer portion; 72, second busbar layer; 721, first laminating portion; 722, second laminating portion; 723, second buffer portion; 73, bending portion;

[0114] 80, mounting beam;

[0115] X, thickness direction; Y, first direction; Z, vertical direction. DETAILED DESCRIPTION

[0116] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0117] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, all terms used in disclosing the application, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms used in the description of the disclosed subject matter should not be interpreted as identifying key

[0118] Reference throughout this application to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all directed to the same embodiment, nor are they necessarily all mutually exclusive or alternative embodiments.

[0119] In the description of the application, it is necessary to explain that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "attaching" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0120] The term "and / or" in this application is only a description of the association relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that there are three cases of A alone, A and B together, and B alone. In addition, the character " / " in this application generally represents that the front and rear associated objects have an "or" relationship.

[0121] In the embodiments of the application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the application shown in the drawings, as well as the overall thickness, length and width of the integrated device, are only exemplary and should not constitute any limitation on the application.

[0122] "RANGES" disclosed herein are defined, for each range by endpoints, to include the endpoint members when the variable being defined is a member inclusive range, as well as arbitrarily combinable to form a range. For example, if a range from 60 to 120 is listed as exemplary of a certain parameter, it is to be understood that a range from 60 to 110, from 60 to 105, from 60 to 99, from 60 to 95, from 60 to 90, from 60 to 80, from 60 to 70, from 60 to 65 or even from 60 to 60, would also be contemplated by the disclosure, as well as the ranges 61 to 120, 62 to 120, 63 to 120, 64 to 120, 65 to 120, 66 to 120, 67 to 120, 68 to 120, 69 to 120, 70 to 120, 71 to 120, 72 to 120, 73 to 120, 74 to 120, 75 to 120, 76 to 120, 77 to 120, 78 to 120, 79 to 120, 80 to 120, 81 to 120, 82 to 120, 83 to 120, 84 to 120, 85 to 120, 86 to 120, 87 to 120, 88 to 120, 89 to 120, 90 to 120, 91 to 120, 92 to 120, 93 to 120, 94 to 120, 95 to 120, 96 to 120, 97 to 120, 98 to 120, 99 to 120, 100 to 120, 101 to 120, 102 to 120, 103 to 120, 104 to 120, 105 to 120, 106 to 120, 107 to 120, 108 to 120, 109 to 120, 110 to 120, 111 to 120, 112 to 120, 113 to 120, 114 to 120, 115 to 120, 116 to 120, 117 to 120, 118 to 120, 119 to 120, 120 to 120, and so forth, would also be contemplated. In this application, numerical ranges are inclusive of the endpoints, unless specifically indicated otherwise. For example, a numerical range "a to b" indicates "a to b" is intended to mean any number that falls within the range, including the end points a and b, where a and b are both real numbers. For example, the numerical range "0 to 5" indicates that all real numbers between 0 and 5 have been listed herein, "0 to 5" is merely a shorthand for listing all of the numbers between 0 and 5. Also, when a parameter is stated to be an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0123] "Plural" appearing herein indicates two or more (including two).

[0124] At present, from the development of market situation, the application of battery is more and more widely. The battery is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely applied to electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, aerospace and other fields. With the continuous expansion of the application field of battery, the market demand is also increasing.

[0125] The battery generally refers to a single physical module including a plurality of battery monomers to provide higher voltage and capacity. The battery monomer can be the smallest unit constituting the battery.

[0126] With the development of the battery, especially widely used in daily life, users hope that the battery can be charged faster to adapt to the needs of fast-paced modern life. However, in the process of fast charging, the heat generation of the battery monomer increases, so that the battery monomer is maintained in a high temperature range during the whole charging process, which affects the cycle performance and cycle life of the battery, and aggravates the risk of thermal runaway of the battery.

[0127] In view of this, the embodiments of the present application provide a battery, which sets a heat exchange member, and exchanges heat between the heat exchange member and the side wall with large area of the battery monomer, so as to improve the heat exchange efficiency, reduce the risk of thermal runaway of the battery monomer in the process of fast charging, reduce the temperature rise of the battery monomer, and improve the cycle performance and cycle life of the battery monomer.

[0128] The battery described in the embodiments of the present application is suitable for use in a power consuming device using a battery. The power consuming device can be a device using a battery as a power source or various energy storage systems using a battery as an energy storage element. The power consuming device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, and an electric aircraft toy, and the spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, and the like.

[0129] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0130] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application.

[0131] As shown in FIG. 1, a vehicle 1 is internally provided with a battery 2, which can be arranged at the bottom, the head, or the tail of the vehicle 1. The battery 2 can be used for power supply of the vehicle 1, for example, the battery 2 can be used as an operating power source of the vehicle 1.

[0132] The vehicle 1 can further include a controller 3 and a motor 4, the controller 3 being used to control the battery 2 to supply power to the motor 4, for example, for the working power demand of the vehicle 1 during starting, navigation, and driving.

[0133] In some embodiments of the present application, the battery 2 can not only be used as an operating power source of the vehicle 1, but also be used as a driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0134] FIG. 2 is a schematic diagram of a battery provided by some embodiments of the present application.

[0135] Referring to FIG. 2, in some embodiments, the battery 2 includes a box body 20 and a plurality of battery monomers 10 contained in the box body 20.

[0136] The battery monomer 10 can be a secondary battery, which refers to a battery monomer that can be activated by charging after discharging of the battery monomer.

[0137] Exemplarily, the battery monomer 10 can be a lithium ion battery monomer, a sodium ion battery monomer, a sodium lithium ion battery monomer, a lithium metal battery monomer, a sodium metal battery monomer, a lithium sulfur battery monomer, a magnesium ion battery monomer, a nickel hydrogen battery monomer, a nickel cadmium battery monomer, a lead storage battery monomer, and the like.

[0138] As an example, the battery cell 10 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes, the prismatic battery cell including a square-shaped battery cell, a blade-shaped battery cell, a multi-prismatic battery cell, such as a hexagonal battery cell, etc.

[0139] The plurality of battery cells 10 can be connected in series, in parallel, or in a mixed connection, the mixed connection referring to a connection in which both series and parallel connections are present among the plurality of battery cells 10. The plurality of battery cells 10 can be directly connected in series, in parallel, or in a mixed connection, and the whole of the plurality of battery cells 10 can be accommodated in the case 20. Alternatively, the plurality of battery cells 10 can be connected in series, in parallel, or in a mixed connection to form a battery module, and a plurality of battery modules can be connected in series, in parallel, or in a mixed connection to form a whole, which can be accommodated in the case 20.

[0140] In some embodiments, the battery 2 includes a plurality of busbar components that connect the plurality of battery cells 10 in series, in parallel, or in a mixed connection.

[0141] In some embodiments, the case 20 can be a part of a chassis structure of a vehicle. For example, a part of the case 20 can be at least a part of a floor of the vehicle, or a part of the case 20 can be at least a part of a cross beam and a longitudinal beam of the vehicle.

[0142] FIG. 3 is an exploded view of a battery cell according to some embodiments of the present application.

[0143] Referring to FIG. 3, in some embodiments, the battery cell 10 includes a housing 12 and an electrode assembly 11 accommodated in the housing 12.

[0144] The housing 12 is a hollow structure having an accommodation space for accommodating the electrode assembly 11 and an electrolyte. The shape of the housing 12 can be determined according to the specific shape of the electrode assembly 11. For example, if the electrode assembly 11 has a cuboid shape, a cuboid housing can be used.

[0145] As an example, the housing 12 includes a housing body 121 having an opening and an end cap 122 for closing the opening.

[0146] The housing body 121 is a component for cooperating with the end cap 122 to form an internal cavity of the battery cell 10, and the internal cavity can be used to accommodate the electrode assembly 11, the electrolyte, and other components.

[0147] The housing body 121 and the end cap 122 can be separate components. As an example, the housing body 121 can be provided with an opening, and the internal cavity of the battery cell 10 can be formed by closing the opening with the end cap 122.

[0148] The shell 121 can be in various shapes and sizes, such as a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the shell 121 can be determined according to the specific shape and size of the electrode assembly 11. The material of the shell 121 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the present application does not make special limitations on this.

[0149] The shape of the end cover 122 can be adapted to the shape of the shell 121 to fit the shell 121. The material of the end cover 122 can be the same as or different from that of the shell 121. Optionally, the end cover 122 can be made of a material with certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cover 122 is not easy to deform when subjected to extrusion and collision, so that the battery monomer 10 can have higher structural strength, and the reliability can also be improved.

[0150] The end cover 122 is connected to the shell 121 by welding, bonding, clamping or other means.

[0151] The shell 121 can be open at one end or both ends. In some examples, the shell 121 can be a structure open on one side, and the end cover 122 is provided as one and covers the shell 121. In other examples, the shell 121 can also be a structure open on both sides, and the end cover 122 is provided as two, and the two end covers 122 cover the two openings of the shell 121 respectively.

[0152] The electrode assembly 11 is a component in which electrochemical reactions occur in the battery monomer 10. The shell 121 can contain one or more electrode assemblies 11.

[0153] In some embodiments, the electrode assembly 11 includes a positive electrode sheet and a negative electrode sheet. During the charging and discharging process of the battery monomer 10, active ions (such as lithium ions) are embedded and extracted between the positive electrode sheet and the negative electrode sheet.

[0154] In some embodiments, the electrode assembly 11 further includes a separator film, which is arranged between the positive electrode sheet and the negative electrode sheet, and can prevent the positive and negative electrodes from short-circuiting while allowing the active ions to pass through.

[0155] In some embodiments, the electrode assembly 11 includes an electrode body 11a, a first tab 11b and a second tab 11c, and the first tab 11b and the second tab 11c are drawn from the electrode body 11a. The first tab 11b and the second tab 11c are opposite in polarity, that is, one of the first tab 11b and the second tab 11c is a positive tab, and the other is a negative tab.

[0156] As an example, the portion of the positive electrode sheet having the active material, the portion of the negative electrode sheet having the active material, and the separator film constitute the electrode assembly 11. The portion of the positive electrode sheet not having the active material constitutes the positive electrode tab, and the portion of the negative electrode sheet not having the active material constitutes the negative electrode tab. The positive electrode tab and the negative electrode tab can be located together at one end of the electrode body 11a or at two ends of the electrode body 11a, respectively.

[0157] In some embodiments, the electrode assembly 11 is a jelly-roll structure. The positive electrode sheet and the negative electrode sheet are wound to form the jelly-roll structure.

[0158] In some embodiments, the electrode assembly 11 is a stack structure.

[0159] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be provided, and the plurality of positive electrode sheets and the plurality of negative electrode sheets can be alternately stacked.

[0160] As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet can be folded to form a plurality of folded segments that are stacked. One positive electrode sheet can be interposed between adjacent folded segments.

[0161] As an example, the positive electrode sheet and the negative electrode sheet can be folded to form a plurality of folded segments that are stacked.

[0162] As an example, a plurality of separators can be provided, and each of the plurality of separators can be interposed between any adjacent positive electrode sheet or negative electrode sheet.

[0163] As an example, the separators can be continuously provided, and each of the separators can be interposed between any adjacent positive electrode sheet or negative electrode sheet by being folded or wound.

[0164] In some embodiments, the battery cell 10 includes a first electrode terminal 13 and a second electrode terminal 14 that are insulated from each other, the first electrode terminal 13 is electrically connected to the first tab 11b, and the second electrode terminal 14 is electrically connected to the second tab 11c.

[0165] The first electrode terminal 13 and the second electrode terminal 14 are used to be electrically connected to an external circuit to charge or discharge the battery cell 10.

[0166] As an example, the first electrode terminal 13 can be a separately formed member that is mounted to the case 12. Alternatively, the first electrode terminal 13 can be a part of the case 12.

[0167] As an example, the second electrode terminal 14 can be a separately formed member that is mounted to the case 12. Alternatively, the second electrode terminal 14 can be a part of the case 12.

[0168] In some embodiments, the first electrode terminal 13 and the second electrode terminal 14 are provided to the end cap 122.

[0169] In some embodiments, the battery cell 10 further comprises a pressure relief mechanism 15. The pressure relief mechanism 15 has an important influence on the reliability of the battery cell 10. For example, when a short circuit, overcharge, or the like occurs, thermal runaway may occur inside the battery cell 10, causing a sudden increase in pressure. In this case, the internal pressure can be released outward by actuating the pressure relief mechanism 15 to reduce the risk of explosion or fire of the battery cell 10.

[0170] Illustratively, the pressure relief mechanism 15 refers to an element or component that is actuated to release internal gas when the internal pressure or temperature of the battery cell 10 reaches a predetermined threshold. The threshold is designed differently according to different design requirements. The threshold can depend on the material of one or more of the positive plate, the negative plate, the electrolyte, and the separator in the battery cell 10.

[0171] The pressure relief mechanism 15 can take the form of, for example, a rupture disc, a gas valve, a pressure relief valve, or a safety valve, and can specifically take the form of a pressure-sensitive element or structure, i.e., when the internal pressure of the battery cell 10 reaches a predetermined threshold, the pressure relief mechanism 15 performs an action or a weak zone provided in the pressure relief mechanism 15 breaks, thereby forming an opening or passage for the internal pressure to be released. Alternatively, the pressure relief mechanism 15 can also take the form of a temperature-sensitive element or structure, i.e., when the internal temperature of the battery cell 10 reaches a predetermined threshold, the pressure relief mechanism 15 performs an action, thereby forming an opening or passage for the internal pressure to be released.

[0172] When the battery cell 10 is in thermal runaway, the discharge of the battery cell 10 includes, but is not limited to, electrolyte, dissolved or split positive and negative plates, fragments of the separator, high-temperature and high-pressure gas generated by the reaction, flames, and the like.

[0173] In some embodiments, the pressure relief mechanism 15 is provided in the outer shell 12. Illustratively, the pressure relief mechanism 15 can be provided in the housing 121 or in the end cover 122.

[0174] FIG. 4 is an enlarged view of the circle in FIG. 2; FIG. 5 is a partially cutaway schematic view of a battery according to some embodiments of the present application; FIG. 6 is a cross-sectional view of an electrode assembly of a battery cell according to some embodiments of the present application; FIG. 7 is a schematic view of a negative plate of a battery cell according to some embodiments of the present application; and FIG. 8 is a schematic view of a positive plate of a battery cell according to some embodiments of the present application.

[0175] Referring to FIGS. 2 to 8, the present embodiments provide a battery 2, which includes a battery cell 10, a box 20, and a heat exchange member 30.

[0176] The battery cell 10 is accommodated in the box 20. The battery cell 10 includes an outer shell 12 and an electrode assembly 11 accommodated in the outer shell 12, and the outer shell 12 includes two first side walls 12d arranged opposite to each other in the thickness direction X of the battery cell 10.

[0177] The heat exchange member 30 is arranged on at least one side of the battery cell 10 along the thickness direction X and is used for heat exchange with the first side wall 12d.

[0178] The electrode assembly 11 comprises a positive electrode sheet 111, a negative electrode sheet 112, and a separator 113 between the positive electrode sheet 111 and the negative electrode sheet 112, the positive electrode sheet 111 comprises a positive electrode current collector 1111 and a positive electrode film layer 1112 arranged on at least one side of the positive electrode current collector 1111, the positive electrode film layer 1112 comprises a positive electrode active material, and the positive electrode active material comprises a lithium-containing phosphate with an olivine structure; the negative electrode sheet 112 comprises a negative electrode current collector 1121 and a negative electrode film layer 1122 arranged on at least one side of the negative electrode current collector 1121, the negative electrode film layer 1122 comprises a negative electrode active material, and the negative electrode active material comprises a carbon-based material.

[0179] As an example, the battery cell 10 is multiple.

[0180] The battery cell 10 can comprise one or more electrode assemblies 11.

[0181] The electrode assembly 11 can be wholly contained in the shell 12 or partially contained in the shell 12.

[0182] The heat exchange member 30 can be one or more. As an example, the battery cell 10 can exchange heat with only one heat exchange member 30 or simultaneously exchange heat with multiple heat exchange members 30.

[0183] The heat exchange member 30 can directly contact the first side wall 12d for heat exchange or indirectly exchange heat with the shell 12 through other heat-conducting structures.

[0184] In some examples, one first side wall 12d of the battery cell 10 exchanges heat with the heat exchange member 30. Alternatively, two first side walls 12d of the battery cell 10 respectively exchange heat with two heat exchange members 30.

[0185] The heat exchange member 30 can be an integrally formed component or be spliced from multiple independently formed sub-components.

[0186] In the embodiments of the present application, the negative electrode film layer 1122 can be arranged on only one side of the negative electrode current collector 1121 or on both sides of the negative electrode current collector 1121.

[0187] Optionally, the negative electrode film layer 1122 is arranged on both surfaces of the negative electrode current collector 1121 opposite along the thickness direction of the negative electrode current collector 1121. The negative electrode film layers 1122 on the two surfaces of the negative electrode current collector 1121 can adopt the same negative electrode active material or different negative electrode active materials; the thicknesses of the negative electrode film layers 1122 on the two surfaces of the negative electrode current collector 1121 can be the same or different.

[0188] Exemplarily, the negative current collector 1121 can adopt a metal foil or a composite current collector. As an example of the metal foil, at least one of a copper foil, a copper alloy foil, a nickel foil, a nickel alloy foil, a titanium foil, a titanium alloy foil, a silver foil and a silver alloy foil can be adopted. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material in the metal material layer can include at least one of copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver and a silver alloy. As an example, the polymer material base layer can include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0189] The negative active material includes a carbon-based material. The carbon-based material has high cycle stability, which can improve the cycle performance of the battery monomer 10.

[0190] The positive current collector 1111 has two surfaces opposite in the thickness direction of the positive current collector 1111, and the positive film layer 1112 is arranged on any one or both of the two opposite surfaces of the positive current collector 1111.

[0191] Exemplarily, the positive current collector 1111 can adopt a metal foil or a composite current collector. As an example of the metal foil, at least one of an aluminum foil, an aluminum alloy foil, a nickel foil, a nickel alloy foil, a titanium foil, a titanium alloy foil, a silver foil and a silver alloy foil can be adopted. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material in the metal material layer can include at least one of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver and a silver alloy. As an example, the polymer material base layer can include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0192] In the embodiment of the present application, the first side wall 12d can be the largest shell wall of the shell 12, and the first side wall 12d exchanges heat with the heat exchange member 30, which can improve the heat exchange efficiency, thereby reducing the temperature rise of the battery monomer 10 during fast charging, improving the cycle performance and cycle life of the battery monomer, reducing the risk of thermal runaway, and improving the reliability. The carbon-based material and the lithium-containing phosphate have high cycle stability, and the lithium-containing phosphate is used as the positive active material and the carbon-based material is used as the negative active material, which can improve the cycle decay of the battery monomer caused by the temperature rise during fast charging, and improve the cycle performance of the battery monomer 10. In the embodiment of the present application, the carbon-based material and the lithium-containing phosphate are used as the negative active material and the positive active material respectively, and the first side wall 12d exchanges heat with the heat exchange member 30, which can improve the fast charging capacity of the battery monomer, reduce the influence of heat generation during fast charging on the cycle performance of the battery monomer, save the charging time, and improve the user experience.

[0193] In some embodiments, the charging time of the battery cell 10 from 10% SOC to 80% SOC is 5 minutes to 10.5 minutes at room temperature.

[0194] As an example, the room temperature can be an ambient temperature of 30°C.

[0195] SOC refers to the state of charge of the battery cell 10.

[0196] As an example, 100% SOC and 0% SOC are defined as follows: charging the battery cell to a battery upper limit voltage at a constant current charging rate of 0.33C, and then charging at a constant voltage to 0.05C, corresponding to the state of 100% SOC of the battery cell; discharging the battery cell to a cut-off voltage at a constant current discharge rate of 0.33C, corresponding to the state of 0% SOC of the battery cell. As an example, the battery upper limit voltage can be 3.8V; the battery discharge cut-off voltage can be 2.0V.

[0197] As an example, the charging time of the battery cell 10 from 10% SOC to 80% SOC is 10.5 minutes, 10 minutes, 9.5 minutes, 9 minutes, 8.5 minutes, 8 minutes, 7.5 minutes, 7 minutes, 6.5 minutes, 6 minutes, 5.5 minutes, 5 minutes, or a range formed by any two of the above values.

[0198] In the embodiments of the present application, the battery cell 10 has a fast charging capability, which can save charging time and improve user experience. In the fast charging process of the battery cell 10, the heat exchange member 30 can exchange heat with the first side wall 12d to reduce the temperature rise of the battery cell 10 during the fast charging process; the carbon-based material and the lithium-containing phosphate have high cycle stability, which can improve the cycle decay of the battery cell caused by the temperature rise during the fast charging process.

[0199] In some embodiments, the charging steps of the battery 2 or any battery cell 10 constituting the battery 2 from 10% SOC to 80% SOC can be performed as follows:

[0200] charging from 10% SOC to 15% SOC at a constant current of 5.0C;

[0201] charging from 15% SOC to 20% SOC at a constant current of 5.0C;

[0202] charging from 20% SOC to 25% SOC at a constant current of 5.0C;

[0203] charging from 25% SOC to 30% SOC at a constant current of 5.0C;

[0204] from 30% SOC to 35% SOC at 5.0C constant current;

[0205] from 35% SOC to 40% SOC at 5.0C constant current;

[0206] from 40% SOC to 45% SOC at 4.6C constant current;

[0207] from 45% SOC to 50% SOC at 4.3C constant current;

[0208] from 50% SOC to 55% SOC at 4.0C constant current;

[0209] from 55% SOC to 60% SOC at 3.7C constant current;

[0210] from 60% SOC to 65% SOC at 3.4C constant current;

[0211] from 65% SOC to 70% SOC at 3.1C constant current;

[0212] from 70% SOC to 75% SOC at 2.9C constant current;

[0213] from 75% SOC to 80% SOC at 2.7C constant current.

[0214] As an example, the above charging strategy is performed in an environment of 30°C.

[0215] In some embodiments, the battery cell 10 charging step from 0% SOC to 10% SOC can be performed as follows: from 0% SOC to 10% SOC at 5.0C constant current.

[0216] In some embodiments, the battery cell 10 charging step from 80% SOC to 98% SOC can be performed as follows:

[0217] from 80% SOC to 85% SOC at 1.8C constant current;

[0218] from 85% SOC to 90% SOC at 1.3C constant current;

[0219] from 90% SOC to 95% SOC at 0.7C constant current;

[0220] from 95% SOC to 98% SOC at 0.33C constant current.

[0221] In some embodiments, the battery cell 10 charging step from 98% SOC to 100% SOC can be performed as follows: constant current charging from 98% SOC to 100% SOC at 0.01C, 0.05C, 0.1C, or 0.3C. Alternatively, the battery cell 10 charging step from 98% SOC to 100% SOC can be performed as follows: constant current charging from 98% SOC to 100% SOC at 0.01C, 0.05C, or 0.1C.

[0222] In some embodiments, the battery cell 10 charging step from 10% SOC to 80% SOC can be performed at room temperature with a charging current of 2C-6C, optionally 2.7C-5C. The charging current can vary during the charging step based on the SOC of the battery cell 10.

[0223] In some embodiments, the battery cell 10 is a lithium ion battery cell. After cycling the battery cell 10 for 20 cycles according to the charging and discharging strategies, the anode tab at the battery cell 10 is disassembled and the lithium plating area of the anode tab is observed and measured. The ratio of the lithium plating area to the total area of the anode tab is less than 2%.

[0224] As an example, the discharging strategy can be discharging at a constant current of 0.33C to 2.0V.

[0225] As an example, the charging strategy can be:

[0226] charging from 0% SOC to 5% SOC at a constant current of 5.0C;

[0227] charging from 5% SOC to 10% SOC at a constant current of 5.0C;

[0228] charging from 10% SOC to 15% SOC at a constant current of 5.0C;

[0229] charging from 15% SOC to 20% SOC at a constant current of 5.0C;

[0230] charging from 20% SOC to 25% SOC at a constant current of 5.0C;

[0231] charging from 25% SOC to 30% SOC at a constant current of 5.0C;

[0232] charging from 30% SOC to 35% SOC at a constant current of 5.0C;

[0233] charging from 35% SOC to 40% SOC at a constant current of 5.0C;

[0234] charging from 40% SOC to 45% SOC at a constant current of 4.6C;

[0235] charged from 45% SOC to 50% SOC at 4.3C constant current;

[0236] charged from 50% SOC to 55% SOC at 4.0C constant current;

[0237] charged from 55% SOC to 60% SOC at 3.7C constant current;

[0238] charged from 60% SOC to 65% SOC at 3.4C constant current;

[0239] charged from 65% SOC to 70% SOC at 3.1C constant current;

[0240] charged from 70% SOC to 75% SOC at 2.9C constant current;

[0241] charged from 75% SOC to 80% SOC at 2.7C constant current;

[0242] charged from 80% SOC to 85% SOC at 1.8C constant current;

[0243] charged from 85% SOC to 90% SOC at 1.3C constant current;

[0244] charged from 90% SOC to 95% SOC at 0.7C constant current;

[0245] charged from 95% SOC to 98% SOC at 0.33C constant current;

[0246] charged from 98% SOC to 100% SOC at 0.1C constant current.

[0247] The battery cell 10 of the embodiments of the present application can be charged from 10% SOC to 80% SOC within 10.5 minutes without lithium precipitation or with slight lithium precipitation, and has good rapid charging capability. For example, the ratio of the area of the lithium precipitation region to the total area of the negative electrode sheet is less than 0.05% for no lithium precipitation, and the ratio of the area of the lithium precipitation region to the total area of the negative electrode sheet is less than 2% and greater than or equal to 0.05% for slight lithium precipitation.

[0248] In some embodiments, the battery cell 10 is a square cell.

[0249] In some embodiments, the housing 12 includes two first side walls 12d oppositely arranged along the thickness direction X of the battery cell 10 and two second side walls 12e oppositely arranged along a first direction Y perpendicular to the thickness direction X, and each second side wall 12e connects the two first side walls 12d.

[0250] In some embodiments, the first side wall 12d and the second side wall 12e are both flat walls and are arranged perpendicularly.

[0251] In some embodiments, one first side wall 12d of the battery cell 10 is connected with the heat exchange member 30.

[0252] The lithium-containing phosphate with olivine structure has excellent cycle stability. The lithium-containing phosphate with olivine structure can reduce the heat generation of the battery cell 10 during fast charging and reduce the risk of thermal runaway of the battery cell 10. The lithium-containing phosphate with olivine structure can reduce the heat exchange requirement. In the embodiments of the present application, only one first side wall 12d of the battery cell 10 is connected with the heat exchange member 30, which can reduce the number of heat exchange members 30, save space, and improve the energy density of the battery 2.

[0253] Of course, in alternative embodiments, if the capacity of the battery 2 meets the requirements, two first side walls 12d of the battery cell 10 can be respectively connected with two heat exchange members 30 to improve the temperature control effect.

[0254] In some embodiments, the battery 2 includes a plurality of battery cell groups 100 and a plurality of heat exchange members 30. The plurality of battery cell groups 100 are arranged along the thickness direction X. Each battery cell group 100 includes at least two battery cells 10 arranged along a direction perpendicular to the thickness direction X. One heat exchange member 30 is arranged between every two battery cell groups 100.

[0255] For example, the battery cells 10 of the battery cell group 100 are arranged along the first direction Y.

[0256] For example, the plurality of battery cells 10 of the battery 2 are arrayed in the box 20.

[0257] For example, the number of battery cells 10 of adjacent battery cell groups 100 can be the same or different.

[0258] The number of battery cell groups 100 can be even or odd.

[0259] In some examples, the number of battery cell groups 100 is 2n, where n is a positive integer. One heat exchange member 30 is arranged between the 2k-1th battery cell group 100 and the 2kth battery cell group 100 along the thickness direction X, where k is a natural number from 1 to n. The number of heat exchange members 30 can be n.

[0260] In some examples, the number of the battery cell groups 100 can be 2n+1, n being a positive integer. Along the thickness direction X, one heat exchange member 30 is arranged between the 2k-1th battery cell group 100 and the 2kth battery cell group 100, k being a natural number from 1 to n. The number of the heat exchange members 30 can be n+1, and one heat exchange member 30 can be arranged corresponding to the 2n+1th battery cell group 100. The heat exchange member 30 can be arranged on the side of the 2n+1th battery cell group 100 away from the 2nth battery cell group 100, or between the 2n+1th battery cell group 100 and the 2nth battery cell group 100.

[0261] In the embodiments of the present application, one heat exchange member 30 can exchange heat with the battery cells 10 of two battery cell groups 100 at the same time, which can reduce the number of the heat exchange members 30 and improve the space utilization and energy density of the battery 2.

[0262] In some examples, the heat exchange member 30 is a plurality of heat exchange members 30 arranged along the thickness direction X. Two battery cell groups 100 are arranged between adjacent heat exchange members 30.

[0263] In some examples, the battery cell group 100 includes m battery cells 10, m being a positive integer greater than 1. The m battery cells 10 of the battery cell group 100 are connected to the same heat exchange member 30.

[0264] In some examples, the heat exchange member 30 is bonded to the first side wall 12d by a first adhesive layer 40. The first adhesive layer 40 can stably connect the heat exchange member 30 and the first side wall 12d, so as to improve the stability of heat exchange between the heat exchange member 30 and the battery cells 10.

[0265] In some examples, the first adhesive layer 40 is a thermally conductive adhesive layer.

[0266] In some examples, the heat exchange member 30 includes a thermally conductive plate 31, and the thermally conductive plate 31 is internally provided with a flow channel 311 for arranging a heat exchange medium.

[0267] As an example, the heat exchange medium can be a liquid or a gas, such as water.

[0268] The flow channel 311 can guide the flow of the heat exchange medium, so that the heat exchange medium exchanges heat with the battery cells 10 when flowing through the thermally conductive plate 31.

[0269] In some examples, the thermally conductive plate 31 is a metal plate or a non-metal plate.

[0270] In some examples, the heat exchange member 30 further includes an insulating layer 32, and at least part of the insulating layer 32 is arranged between the thermally conductive plate 31 and the first side wall 12d.

[0271] The insulation layer 32 can insulate the heat-conducting plate 31 from the first side wall 12d, increase the creepage distance between the heat-conducting plate 31 and the first side wall 12d, and reduce the risk of short circuit.

[0272] In some embodiments, the insulation layer 32 is arranged on the outer surface of the heat-conducting plate 31.

[0273] In some embodiments, the insulation layer 32 is bonded to the first adhesive layer 40.

[0274] In some embodiments, the heat-conducting plate 31 is made of an insulating non-metallic material, and the insulation layer can be omitted accordingly.

[0275] In some embodiments, the thermal conductivity of the insulation layer 32 is greater than or equal to 0.1 W / (m·K). The insulation layer 32 has good heat conduction capacity, thereby improving the heat exchange efficiency.

[0276] In some embodiments, at least part of the heat exchange member 30 is configured to be deformable in the thickness direction X. The battery cell 10 may swell during the cycle process, and the heat exchange member 30 can be compressed when the battery cell 10 swells, thereby providing space for the swelling of the battery cell 10, reducing the pressure on the electrode assembly 11, and improving the cycle performance of the battery cell 10.

[0277] In some embodiments, the battery 2 further comprises a connection pipe set 50 for connecting a plurality of heat exchange members 30. The connection pipe set 50 can be in communication with the flow channels 311 of the plurality of heat exchange members 30, thereby realizing the flow of the heat exchange medium in the flow channels 311.

[0278] For example, the connection pipe set 50 comprises an inlet pipe and an outlet pipe, the inlet pipe being in communication with the flow channels 311 of the plurality of heat exchange members 30, and the outlet pipe being in communication with the flow channels 311 of the plurality of heat exchange members 30.

[0279] The inlet pipe and the outlet pipe can be located on the same side of the plurality of battery cells 10, or can be arranged on the two sides of the plurality of battery cells 10, respectively. Alternatively, the inlet pipe and the outlet pipe are arranged on the two sides of the plurality of battery cells 10 along the first direction Y, respectively.

[0280] In some embodiments, the housing 12 further comprises a first end wall 12a and a second end wall 12b arranged oppositely, and the first side wall 12d connects the first end wall 12a and the second end wall 12b. The first end wall 12a is located on the lower side of the electrode assembly 11, and the second end wall 12b is located on the upper side of the electrode assembly 11 and connected to the tank 20.

[0281] As an example, when the battery cell 10 is installed in an electrical device, the second end wall 12b can be located on the upper side of the electrode assembly 11 along the vertical direction Z, and the first end wall 12a can be located on the lower side of the electrode assembly 11 along the vertical direction Z. During the production, transportation, and the like of the battery cell 10, it is not required that the second end wall 12b is on the upper side and the first end wall 12a is on the lower side.

[0282] Fixing the second end wall 12b to the case 20 can save the space on the upper side of the battery cell 10 and improve the space utilization.

[0283] In some embodiments, the second side wall 12e connects the first end wall 12a and the second end wall 12b.

[0284] In some embodiments, the second end wall 12b is bonded to the case 20.

[0285] As an example, the second end wall 12b is bonded to the case 20 through a second adhesive layer 41. The second adhesive layer 41 can fix the battery cell 10 to the case 20, thereby improving the stability of the battery cell 10. The second adhesive layer 41 is convenient for molding and is conducive to simplifying the assembly process.

[0286] In some embodiments, the case 20 includes a first case wall 21, and the battery cell 10 is located on the lower side of the first case wall 21. As an example, the second end wall 12b is bonded to the first case wall 21 through the second adhesive layer 41.

[0287] As an example, the first end wall 12a is located on the side of the electrode assembly 11 away from the first case wall 21.

[0288] The first case wall 21 can be a single-layer structure or a multi-layer structure. The first case wall 21 can be an integrally formed component or can be connected by a plurality of independently formed components.

[0289] In some embodiments, the battery cell 10 further includes a pressure relief mechanism 15 disposed on the first end wall 12a.

[0290] The first end wall 12a can be an end cover 122 or a wall of a housing 121.

[0291] In some examples, the pressure relief mechanism 15 and the first end wall 12a can be independently formed components, and the two can be connected by welding, bonding, or other means. For example, the first end wall 12a is provided with a pressure relief hole that penetrates the first end wall 12a, the pressure relief mechanism 15 is installed on the first end wall 12a and covers the pressure relief hole, so as to separate the space on the inside and outside of the first end wall 12a. In alternative embodiments, the pressure relief mechanism 15 and the first end wall 12a can also be an integrally formed structure.

[0292] In the rapid charging process of the battery 2, even if the battery cell 10 is in thermal runaway due to an accident, the high-temperature substance generated by the battery cell 10 can be ejected downward via the pressure relief mechanism 15, thereby reducing the thermal impact on the upper side of the battery 2, reducing the risk of user injury, and improving the reliability of the battery 2 and the electric device using the battery 2.

[0293] In some embodiments, the pressure relief mechanism 15 includes a weak portion 151. The weak portion 151 is a portion of the pressure relief mechanism 15 that has relatively low strength, and is a portion of the pressure relief mechanism 15 that is easily broken, fractured, torn, or opened.

[0294] In some examples, the present application can open a groove, a notch, or other structure in a predetermined area of the pressure relief mechanism 15 to reduce the strength of the pressure relief mechanism 15 in the local area, thereby forming the weak portion 151 on the pressure relief mechanism 15. For example, a thinning process is performed on a predetermined area of the pressure relief mechanism 15, and the portion of the pressure relief mechanism 15 that is thinned forms the weak portion 151. In other examples, a material treatment can be performed on a predetermined area of the pressure relief mechanism 15, so that the strength of the area is weaker than that of other areas, in other words, the area is the weak portion 151.

[0295] In some embodiments, the pressure relief mechanism 15 and the first end wall 12a are independently formed, and the pressure relief mechanism 15 is fixed to the first end wall 12a.

[0296] Illustratively, the pressure relief mechanism 15 includes a pressure relief portion 152, a weak portion 151, and a fixed portion 153, the weak portion 151 is disposed along the outer periphery of the pressure relief portion 152 and connects the pressure relief portion 152 and the fixed portion 153, and the fixed portion 153 can be used to fixedly connect to the first end wall 12a.

[0297] Optionally, the weak portion 151 surrounds the pressure relief portion 152.

[0298] Optionally, the fixed portion 153 is welded to the first end wall 12a.

[0299] In other embodiments, the pressure relief mechanism 15 and the first end wall 12a are integrally formed. Integrally forming the pressure relief mechanism 15 and the first end wall 12a can save the space required for connecting the pressure relief mechanism 15 and the first end wall 12a, provide more space for the pressure relief mechanism 15, improve the pressure relief efficiency, and improve the reliability of the battery 2.

[0300] Integrally forming the pressure relief mechanism 15 and the first end wall 12a can also eliminate the conventional welding process, reduce the thermal impact on the weak portion 151 of the pressure relief mechanism 15, and improve the stability of the pressure relief mechanism 15.

[0301] As an example, a groove, a notch or other structure can be formed on the first end wall 12a to form an annular weakened portion 151. The weakened portion 151 and the area surrounded by the weakened portion 151 constitute the pressure relief mechanism 15.

[0302] As an example, the first end wall 12a can be a bottom wall of the shell 121.

[0303] In some embodiments, the shell 121 includes a second end wall 12b, two first side walls 12d and two second side walls 12e. The first end wall 12a is an end cover 122.

[0304] In some embodiments, the battery cell 10 further includes a sampling member 16 disposed in the shell 12, the sampling member 16 being configured to sample a temperature of the shell 12.

[0305] The sampling member 16 can be disposed in the shell 12 or outside the shell 12.

[0306] The sampling member 16 can sample the temperature of the shell 12 in real time, so as to monitor and adjust the temperature of the battery cell 10, reduce the risk of abnormal temperature rise of the battery cell 10 during rapid charging, and improve the reliability of the battery 2.

[0307] In some embodiments, the sampling member 16 is disposed on the end cover 122.

[0308] In some embodiments, the sampling member 16 is a plurality of sampling members 16, and the plurality of sampling members 16 can be disposed at positions of the battery cell 10 where the temperature is relatively high during cycling.

[0309] In some embodiments, the sampling member 16 includes a negative temperature coefficient thermistor.

[0310] In some embodiments, the shell 12 further includes a first end wall 12a, the first end wall 12a connecting the two first side walls 12d. The battery cell 10 further includes a first electrode terminal 13 disposed on the first end wall 12a. The electrode assembly 11 includes an electrode body 11a and a first tab 11b extending from the electrode body 11a, and the first electrode terminal 13 is electrically connected to the first tab 11b.

[0311] By disposing the first electrode terminal 13 on the first end wall 12a, the risk of interference between the first electrode terminal 13 and the heat exchange member 30 can be reduced, and the heat exchange efficiency can be improved.

[0312] In some embodiments, the first end wall 12a is located on the lower side of the electrode assembly 11. By disposing the first electrode terminal 13 on the first end wall 12a, the space on the lower side of the battery cell 10 can be fully utilized, and the space utilization rate can be improved.

[0313] In some embodiments, the second electrode terminal 14 is also disposed on the first end wall 12a.

[0314] In some embodiments, at least part of the first electrode terminal 13 is located outside the first end wall 12a.

[0315] The side of the first end wall 12a away from the electrode assembly 11 has an outer surface 1221. Exemplarily, at least part of the first electrode terminal 13 is located outside the plane in which the outer surface 1221 of the first end wall 12a lies.

[0316] In some examples, the first electrode terminal 13 can be located entirely outside the first end wall 12a; alternatively, in other examples, part of the first electrode terminal 13 is located outside the first end wall 12a, and the other part extends through the first end wall 12a and into the housing 12.

[0317] The part of the first electrode terminal 13 located outside the first end wall 12a can be used to connect with the busbar component of the battery 2.

[0318] In some embodiments, the area of the orthogonal projection of the part of the first electrode terminal 13 located outside the first end wall 12a on the first end wall 12a is 200mm 2 -600mm 2 , optionally 200mm 2 , 250mm 2 , 300mm 2 , 350mm 2 , 400mm 2 , 450mm 2 , 500mm 2 , 550mm 2 , or 600mm 2 .

[0319] Exemplarily, the projection of the part of the first electrode terminal 13 located outside the first end wall 12a on the first end wall 12a is the projection of the part of the first electrode terminal 13 located outside the first end wall 12a in the vertical direction Z. The vertical direction Z is parallel to the thickness direction of the first end wall 12a.

[0320] The part of the first electrode terminal 13 located outside the first end wall 12a has a large area, which can increase the overcurrent area, reduce heat generation, reduce the temperature rise of the first electrode terminal 13 during the cycle of the battery 2, and improve reliability. The first electrode terminal 13 has a large exposed area, which can increase the heat dissipation efficiency of the first electrode terminal 13.

[0321] In some embodiments, in the width direction of the first end wall 12a, the size of the first end wall 12a is W1mm, and the size of the part of the first electrode terminal 13 located outside the first end wall 12a is W2mm. W2 and W1 satisfy: 0.4≤W2 / W1≤1.

[0322] Optionally, the width direction of the first end wall 12a is parallel to the thickness direction X of the battery cell 10.

[0323] As an example, W2 / W1 is 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.

[0324] Setting W2 / W1 to be greater than or equal to 0.4 can make the first electrode terminal 13 have a larger exposed area, increase the connection area of the first electrode terminal 13 and the busbar component, improve the overcurrent capacity, reduce the temperature rise, improve the cycle performance of the battery 2, and improve the reliability of the battery 2. Limiting W2 / W1 to be less than or equal to 1 can reduce the space occupied by the first electrode terminal 13 in the width direction, and improve the space utilization.

[0325] In some embodiments, W2 / W1 is 0.6-0.9.

[0326] In some embodiments, the first electrode terminal 13 and the second electrode terminal 14 are arranged apart along the length direction of the first end wall 12a. Optionally, the length direction of the first end wall 12a is parallel to the first direction Y.

[0327] In some embodiments, in the length direction of the first end wall 12a, the pressure relief mechanism 15 is located between the first electrode terminal 13 and the second electrode terminal 14.

[0328] FIG. 9 is a partial cross-sectional view of a battery cell according to some embodiments of the present application.

[0329] In some embodiments, referring to FIG. 9, the first end wall 12a has an inner surface 1222 facing the electrode assembly 11, and the first electrode terminal 13 does not protrude beyond the inner surface 1222 in the direction close to the electrode assembly 11.

[0330] The first electrode terminal 13 can not occupy the internal space of the shell 12, thereby improving the space utilization of the battery cell 10 and improving the energy density of the battery cell 10.

[0331] In some embodiments, the first end wall 12a includes an electrode lead-out hole 1223, the first electrode terminal 13 is located outside the electrode lead-out hole 1223, and the first electrode terminal 13 covers the electrode lead-out hole 1223 in the axial direction of the electrode lead-out hole 1223.

[0332] In some embodiments, the battery cell 10 further includes a first fixing member 17 and a second fixing member 18, the first fixing member 17 at least partially surrounds the first electrode terminal 13 and is fixed to the first electrode terminal 13, and the second fixing member 18 is connected to the first fixing member 17 and is fixedly connected to the first end wall 12a.

[0333] In some embodiments, a portion of the second fixing member 18 is embedded in the first fixing member 17.

[0334] In some embodiments, the second fixing member 18 is welded to the first end wall 12a.

[0335] In some embodiments, the first fixing member 17 is an insulating member. The first fixing member 17 is formed by an injection molding process.

[0336] FIG. 10 is a schematic view of a partial cross section of a battery cell according to some embodiments of the present application.

[0337] Referring to FIG. 10, in some embodiments, the first electrode terminal 13 includes a connecting portion 131 provided with a through hole 1311, and the first tab 11b is inserted into the through hole 1311, and a portion of the first tab 11b is located on a side of the connecting portion 131 away from the electrode body 11a and connected to the connecting portion 131.

[0338] By providing the through hole 1311, the first tab 11b can be led out to the outside of the connecting portion 131, thereby reducing the distance between the connecting portion 131 and the electrode body 11a, improving the internal space utilization of the battery cell 10, and improving the energy density of the battery cell 10.

[0339] In some embodiments, the first tab 11b is welded to the connecting portion 131. The first tab 11b can be directly connected to the first electrode terminal 13, thereby eliminating the conventional adapter piece and improving the energy density.

[0340] In some embodiments, the first electrode terminal 13 includes a terminal body 132 fixed to the first end wall 12a, and the terminal body 132 includes the connecting portion 131, and a cover plate 133 is provided on a side of the connecting portion 131 away from the electrode body 11a and connected to the terminal body 132. The cover plate 133 can be used to separate the through hole 1311 from the external space of the battery cell 10.

[0341] In some embodiments, a recess 134 is provided on a side of the terminal body 132 away from the electrode body 11a, and a bottom wall of the recess 134 is the connecting portion 131. The cover plate 133 is provided on a side of the connecting portion 131 away from the electrode body 11a and used to cover the recess 134.

[0342] The recess 134 can accommodate a portion of the first tab 11b, thereby improving the space utilization. The cover plate 133 separates the external space of the housing 12 from the through hole 1311, achieving sealing and reducing the risk of electrolyte leakage.

[0343] In some embodiments, at least a portion of the cover plate 133 is accommodated in the recess 134. By accommodating the cover plate 133 in the recess 134, the space utilization can be improved.

[0344] In some embodiments, the cover plate 133 is welded to the terminal body 132.

[0345] In some embodiments, the cover plate 133 is spaced apart from the first tab 11b to reduce the risk of the cover plate 133 and the first tab 11b being pressed against each other.

[0346] In some embodiments, the through hole 1311 is a strip-shaped hole extending along the length direction of the first end wall 12a.

[0347] FIG. 11 is a cross-sectional view of a battery according to some embodiments of the present application; and FIG. 12 is an enlarged view of the circular frame in FIG. 11.

[0348] Referring to FIGS. 11 and 12, in some embodiments, the box 20 includes a second box wall 22 disposed on the lower side of the battery cell 10.

[0349] The second box wall 22 can be a single-layer structure or a multi-layer structure.

[0350] The second box wall 22 can protect the battery cell 10 from the bottom side to reduce the risk of the battery cell 10 being impacted by external impurities and improve the reliability of the battery 2.

[0351] In some embodiments, the first box wall 21 and the second box wall 22 are arranged vertically above and below each other along the vertical direction Z.

[0352] In some embodiments, the battery cell 10 is fixed to the first box wall 21, and the weight of the battery cell 10 is mainly borne by the first box wall 21. Therefore, the second box wall 22 can have a smaller thickness and weight.

[0353] In some embodiments, the box 20 further includes a frame 23, and the first box wall 21 and the second box wall 22 are respectively located on the upper side and the lower side of the frame 23. The first box wall 21, the second box wall 22, and the frame 23 define an internal space for accommodating the battery cell 10 and the heat exchange member 30.

[0354] In some embodiments, the second box wall 22 is spaced apart from the battery cell 10.

[0355] When the battery cell 10 is in thermal runaway, the space between the second box wall 22 and the battery cell 10 can serve as a discharge channel to timely discharge the substances released by the battery cell 10 to the outside of the box 20, thereby reducing the risk of explosion of the battery 2. When the second box wall 22 is impacted by external impact, the space between the second box wall 22 and the battery cell 10 can play a blocking role to reduce the impact force transmitted to the battery cell 10, thereby reducing the risk of failure of the battery cell 10 and improving the reliability of the battery 2.

[0356] In some embodiments, the pressure relief mechanism 15, the first electrode terminal 13, and the second electrode terminal 14 are all arranged downward, so that the bottom space of the case 20 can be fully utilized, and the space utilization in the vertical direction Z is improved.

[0357] In some embodiments, the battery 2 further includes a support 60 arranged on the lower side of the housing 12 and used for supporting the housing 12.

[0358] For example, the support 60 is arranged on the lower side of the first end wall 12a and used for supporting the first end wall 12a.

[0359] The support 60 can be one or multiple.

[0360] The support 60 can be in contact with the second case wall 22 or arranged spaced apart from the second case wall 22.

[0361] The support 60 can support the battery cell 10, thereby improving the stability of the battery cell 10 and improving the overall structural strength of the battery 2.

[0362] In some embodiments, the case 20 includes a second case wall 22 arranged on the lower side of the battery cell 10. The support 60 is bonded to the housing 12 and the second case wall 22.

[0363] The support 60 connects the battery cell 10 and the second case wall 22, thereby improving the overall structural strength of the battery 2.

[0364] In some embodiments, the support 60 is provided with a third adhesive layer 42 on both sides. The support 60 is bonded to the second case wall 22 and the first end wall 12a through the two third adhesive layers 42, respectively.

[0365] In some embodiments, the support 60 has a smaller elastic modulus than the second case wall 22.

[0366] The support 60 has a smaller elastic modulus. When the second case wall 22 is subjected to external impact, the support 60 can deform to reduce the force transmitted to the battery cell 10 and reduce the risk of failure of the battery cell 10.

[0367] In some embodiments, the support 60 has a cavity inside. By arranging the cavity, the weight of the support 60 can be reduced, and the compressibility of the support 60 can be improved.

[0368] In some embodiments, the support 60 is multiple. The supports 60 extend along the thickness direction X of the battery cell 10, and the multiple supports 60 are arranged spaced apart along the first direction Y.

[0369] In some embodiments, the first end wall 12a is supported by two supports 60 at both ends in the first direction Y. Exemplarily, in the first direction Y, the first electrode terminal 13, the pressure relief mechanism 15, and the second electrode terminal 14 are arranged between the two supports 60.

[0370] In some embodiments, one support 60 can support two battery cells 10 adjacent in the first direction Y at the same time.

[0371] In some embodiments, a gap is provided between the support 60 and the heat exchange member 30 in the vertical direction Z.

[0372] FIG. 13 is a cross-sectional view of a battery according to some embodiments of the present application; FIG. 14 is an enlarged view of the box in FIG. 13; and FIG. 15 is a cross-sectional view of a support of a battery according to some embodiments of the present application.

[0373] Referring to FIGS. 6, 13-15, in some embodiments, the box 20 includes a plurality of limiting beams 24 arranged at intervals in the thickness direction X of the battery cell 10, and a plurality of battery cells 10 are arranged between adjacent limiting beams 24.

[0374] The limiting beams 24 can be two or more. As an example, a battery cell 10 is arranged between any two adjacent limiting beams 24.

[0375] As an example, the limiting beams 24 are connected to the first box wall 21.

[0376] The limiting beams 24 can be used to limit the swelling deformation of the battery cell 10 in the thickness direction X. The limiting beams 24 can directly abut the battery cell 10 in the thickness direction X; alternatively, other components can be arranged between the limiting beams 24 and the battery cell 10, i.e., the limiting beams 24 limit the swelling of the battery cell 10 through the components.

[0377] The limiting beams 24 have high deformation resistance and can effectively constrain the battery cell 10 in the thickness direction X, reducing the maximum swelling amount of the battery cell 10 in the thickness direction X and improving the cycle performance of the battery cell 10.

[0378] In some embodiments, an insulating pad 43 is arranged between the battery cell 10 and the limiting beam 24.

[0379] In some embodiments, the support 60 is connected to adjacent limiting beams 24.

[0380] The support 60 can be one or multiple.

[0381] The support 60 can be connected to the limiting beam 24 by welding, clamping, fasteners, or other connection methods.

[0382] The support 60 is in a strip structure, a line structure, a beam structure, or other structures. Exemplarily, the support 60 extends along the thickness direction X of the battery cell 10.

[0383] During the cycling of the battery cell 10, the battery cell 10 expands and exerts a force on the limiting beam 24. The support 60 can provide a constraint force on the limiting beam 24, thereby reducing the deformation of the limiting beam 24 and limiting the expansion amount of the battery cell 10, improving the cycling performance of the battery cell 10, and reducing the risk of cracking of the case 20.

[0384] In some embodiments, the support 60 can exert a pre-tightening force on the adjacent limiting beam 24.

[0385] In some embodiments, the support 60 is in a strip structure. The strip structure has low cost and occupies small space; the support 60 in the strip structure can improve the space utilization rate inside the battery 2 and improve the energy density of the battery 2. The support 60 includes a metal strip 61 and an insulating film 62 covering the metal strip 61, and the insulating film 62 separates the metal strip 61 from the first end wall 12a.

[0386] Exemplarily, the metal strip 61 includes a steel strip.

[0387] The metal strip 61 has high strength, which can not only support the battery cell 10 but also effectively constrain the limiting beam 24. The insulating film 62 can insulate and separate the metal strip 61 from the battery cell 10, reducing the risk of short circuit.

[0388] In some embodiments, the support 60 has a cavity 63 inside. By providing the cavity 63, the weight of the support 60 can be reduced.

[0389] In some embodiments, the metal strip 61 has a cavity 63.

[0390] In some embodiments, the support 60 is bonded to the first end wall 12a. The support 60 is bonded to the battery cell 10, which can increase the connection strength of the battery cell 10 and the case 20, reduce the shaking of the battery cell 10 relative to the case 20 when the battery 2 is impacted, and improve the reliability and stability of the battery 2.

[0391] In some embodiments, the support 60 is spaced apart from the second case wall 22 in the vertical direction Z. Alternatively, the support 60 is bonded to the second case wall 22.

[0392] In some embodiments, the support 60 is detachably connected to the limiting beam 24.

[0393] In some embodiments, the support 60 and the limiting beam 24 can be connected by, but not limited to, a bolt connection, a buckle connection, or other detachable connection modes.

[0394] In some embodiments, the battery cell 10 has an expansion pressure in the thickness direction X of 0.5 MPa to 2.4 MPa.

[0395] Optionally, the battery cell 10 has an expansion pressure in the thickness direction X of 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2.0 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, or 2.4 MPa.

[0396] As an example, the expansion pressure of the battery cell 10 can be measured in the following manner:

[0397] Discharge the battery cell at a constant current discharge rate of 1C to 2.0V at an ambient temperature of 45°C;

[0398] Clamp the battery cell between two clamping plates, wherein the two clamping plates are respectively located on both sides of the battery cell in the thickness direction X and cover the large face (the large face is the outer surface of the first side wall 12d);

[0399] Charge the battery cell to 3.8V at a constant current charge rate of 0.8C at an ambient temperature of 45°C, detect and record the pressure exerted by the battery cell on the clamping plate;

[0400] Cycle the battery cell according to the above charging strategy and the charging strategy until the battery cell is cycled to 70% SOH (i.e., the capacity retention rate of the battery cell = the discharge capacity of the battery cell / the nominal capacity of the battery cell = 70%), and record the maximum pressure exerted by the battery cell on the clamping plate;

[0401] Calculate the expansion pressure Q of the battery cell in the thickness direction as: maximum pressure / large face area.

[0402] The expansion pressure of the battery cell 10 is related to the compaction degree of the electrode assembly 11. The battery cell 10 has an expansion pressure in the thickness direction X greater than or equal to 0.5 MPa, thereby improving the compaction degree of the electrode assembly 11 and improving the energy density of the battery cell 10. The expansion pressure of the battery cell 10 in the thickness direction X is less than or equal to 2.4 MPa, to limit the deformation of the electrode assembly 11 during cycling, reduce the risk of the separator of the electrode assembly 11 being deformed in a pleated manner and the risk of the positive and negative electrode sheets being locally spaced apart, reduce polarization, and improve the cycling performance of the battery cell 10.

[0403] The expansion pressure of the battery cell 10 in the thickness direction X is limited to 0.5 MPa-2.4 MPa in the embodiments of the present application, so as to reduce the expansion deformation of the battery cell 10 during fast charging, improve the cycle performance of the battery cell 10, reduce the risk of cracking of the box body 20, and improve the reliability of the battery 2.

[0404] Limiting the expansion pressure of the battery cell 10 to 1.5 MPa-2.0 MPa can reduce the strength requirement of the limiting beam 24 and reduce the cost.

[0405] In some embodiments, the box body 20 includes a plurality of limiting beams 24, which are arranged at intervals along the thickness direction X of the battery cell 10, and a plurality of battery cells 10 are arranged between adjacent limiting beams 24. In the thickness direction X, the distance between two adjacent limiting beams 24 is D1, and the sum of the sizes of all electrode assemblies 11 arranged in the thickness direction X between the two adjacent limiting beams 24 is D2. 85%≤D2 / D1≤92%.

[0406] For example, the number of battery cell groups 100 between adjacent limiting beams 24 is M1. The number of a row of battery cells 10 arranged in the thickness direction X between adjacent limiting beams 24 is M1. Each battery cell 10 includes M2 electrode assemblies 11.

[0407] When the battery 2 is at 0% SOC, the distance between the two limiting beams 24 in the thickness direction X is measured as D1; the battery cell 10 is disassembled and the electrode assemblies 11 are taken out, and the thickness of the M1×M2 electrode assemblies 11 arranged in the thickness direction X is measured and summed up to obtain D2.

[0408] For example, when the battery cell 10 is at % SOC, the size of the electrode assembly 11 in the thickness direction X is T; D2=M1×M2×T.

[0409] D2 / D1 is related to the expansion pressure of the battery cell 10. In the embodiments of the present application, D2 / D1 is limited to be less than or equal to 92%, so as to reduce the expansion pressure of the battery cell 10, reduce the deformation of the battery cell 10 during fast charging, reduce the risk of cracking of the box body 20, and improve the reliability of the battery 2; D2 / D1 is limited to be greater than or equal to 85%, so as to improve the space utilization in the thickness direction X and improve the energy density of the battery 2. Limiting D2 / D1 to 85%-92% can balance the expansion pressure of the battery cell 10 and the energy density of the battery 2 to a certain extent.

[0410] FIG. 16 is a schematic view of a battery cell and a first current collecting component provided in some embodiments of the present application; and FIG. 17 is a schematic view of the first current collecting component of FIG. 16.

[0411] In some embodiments, the battery 2 includes a plurality of battery cells 10 and a plurality of busbar components electrically connecting the plurality of battery cells 10.

[0412] The plurality of busbar components can connect the plurality of battery cells 10 in series, in parallel, or in a mixed connection.

[0413] The plurality of busbar components can have the same structure or different structures.

[0414] In some embodiments, the plurality of busbar components includes at least one first busbar component 70, which includes a first busbar layer 71 and a second busbar layer 72 stacked and connected, and the first busbar layer 71 electrically connects at least two battery cells 10 arranged along the thickness direction X.

[0415] The plurality of busbar components can all be the first busbar component 70 or some of them can be the first busbar component 70.

[0416] The first busbar layer 71 and the second busbar layer 72 can be integrally formed. Alternatively, the first busbar layer 71 and the second busbar layer 72 can be independently formed and connected by welding or other means.

[0417] The first busbar component 70 has at least a double-layer structure, and both the first busbar layer 71 and the second busbar layer 72 of the first busbar component 70 can transmit current, so that the first busbar component 70 has a higher overcurrent area, thereby reducing the heat generation of the first busbar component 70, improving the rapid charging capability of the battery 2, and reducing the risk of thermal runaway.

[0418] Under the premise that the overcurrent area meets the requirements, the first busbar component 70 is provided with a double-layer structure, which can reduce the requirement for the thickness of the first busbar layer 71. The battery cell 10 will swell during the cycle process, thereby stretching the first busbar layer 71. The first busbar layer 71 has a smaller thickness, which is easy to deform to adapt to the deformation of the battery cell 10, thereby reducing the risk of the connection between the battery cell 10 and the first busbar layer 71 being pulled apart and improving the reliability of the battery 2.

[0419] In some embodiments, the first busbar layer 71 has a thickness of 1 mm to 2.5 mm. Alternatively, the first busbar layer 71 has a thickness of 1.2 mm to 1.8 mm. For example, the first busbar layer 71 has a thickness of 1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, or 2.5 mm. The embodiments of the present application select the thickness of the first busbar layer 71 according to the swelling pressure of the battery cell 10, which can balance the overcurrent capacity of the first busbar layer 71 and the deformability of the first busbar layer 71 to some extent, thereby improving the rapid charging capability and reliability of the battery 2.

[0420] In some embodiments, the second busbar layer 72 has a thickness of 1 mm to 2.5 mm. Alternatively, the second busbar layer 72 has a thickness of 1.2 mm to 1.8 mm. For example, the second busbar layer 72 has a thickness of 1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, or 2.5 mm.

[0421] The thickness of the second busbar layer 72 can be selected according to the thickness of the first busbar layer 71 and the overcurrent capacity of the first busbar component. For example, when the first busbar layer 71 has a small thickness, the second busbar layer 72 can have a thickness greater than that of the first busbar layer 71 to improve the overcurrent capacity of the first busbar component.

[0422] In some embodiments, the first busbar layer 71 is connected to the first electrode terminal 13 of one battery cell 10 and the second electrode terminal 14 of another battery cell 10 to connect the two battery cells 10 in series. Alternatively, the first busbar layer 71 is connected to the first electrode terminals 13 of two battery cells 10 to connect the two battery cells 10 in parallel.

[0423] In some embodiments, the first busbar layer 71 is welded to the first electrode terminal 13 and / or the second electrode terminal 14.

[0424] In some embodiments, the first busbar component 70 includes at least one bending portion 73 connecting the first busbar layer 71 and the second busbar layer 72.

[0425] The bending portion 73 can be one or multiple.

[0426] The bending portion 73 can connect the first busbar layer 71 and the second busbar layer 72 and transmit current between the first busbar layer 71 and the second busbar layer 72, thereby improving the overcurrent capacity of the first busbar component 70.

[0427] In some embodiments, the first busbar layer 71 includes a first busbar portion 711, a second busbar portion 712, and a first buffer portion 713 connecting the first busbar portion 711 and the second busbar portion 712, the first busbar portion 711 and the second busbar portion 712 are arranged along the thickness direction X and connected to different battery cells 10.

[0428] For example, the first busbar portion 711 can be connected to the electrode terminal (the first electrode terminal 13 or the second electrode terminal 14) of one or more battery cells 10. The second busbar portion 712 can be connected to the electrode terminal (the first electrode terminal 13 or the second electrode terminal 14) of one or more battery cells 10.

[0429] During the cycle of the battery cell 10, the battery cell 10 expands and exerts a pulling force on the first busbar layer 71; the first buffer portion 713 can release stress by deforming, thereby reducing the stress at the connection between the first busbar portion 711 and the battery cell 10 and the stress at the connection between the second busbar portion 712 and the battery cell 10, and reducing the risk of failure of the connection between the first busbar layer 71 and the battery cell 10.

[0430] In some embodiments, the bending portion 73 is not directly connected to the first buffer portion 713. The bending portion 73 is not directly connected to the first buffer portion 713, thereby reducing the influence of the bending portion 73 on the deformation of the first buffer portion 713 and reducing the difficulty of deforming the first buffer portion 713.

[0431] In some embodiments, the first buffer portion 713 includes an arch structure.

[0432] In some embodiments, the first busbar portion 711 is located on the lower side of the first electrode terminal 13 of one battery cell 10 and connected to the first electrode terminal 13, and the second busbar portion 712 is located on the lower side of the second electrode terminal 14 of another battery cell 10 and connected to the second electrode terminal 14.

[0433] In some embodiments, the second busbar layer 72 includes a first laminated portion 721, a second laminated portion 722, and a second buffer portion 723, the first laminated portion 721 is laminated with the first busbar portion 711 and connected by at least one bending portion 73, the second laminated portion 722 is laminated with the second busbar portion 712 and connected by at least one bending portion 73. The second buffer portion 723 connects the first laminated portion 721 and the second laminated portion 722.

[0434] For example, the first laminated portion 721 is attached to the first busbar portion 711, and the second laminated portion 722 is attached to the second busbar portion 712.

[0435] During the circulation of the battery 2, a part of the current can be transmitted between the first busbar 711 and the second busbar 712 through the first laminated part 721, the second buffer part 723 and the second laminated part 722, and a plurality of conductive paths are formed between the first busbar 711 and the second busbar 712, thereby improving the overcurrent capacity.

[0436] During the circulation of the battery cell 10, the battery cell 10 expands and exerts a pulling force on the first busbar layer 71; both the first buffer part 713 and the second buffer part 723 can release the stress by deforming, thereby reducing the risk of failure of the connection between the first busbar layer 71 and the battery cell 10.

[0437] In some embodiments, the second buffer part 723 at least partially overlaps with the first buffer part 713, so that the deformation regions of the first buffer part 713 and the second buffer part 723 are close to each other, thereby reducing the risk of interference between the first buffer part 713 and the second buffer part 723 when deforming with other parts.

[0438] In some embodiments, the second busbar layer 72 is located on the side of the first busbar layer 71 away from the battery cell 10.

[0439] In some embodiments, the second busbar layer 72 is located on the lower side of the first busbar layer 71.

[0440] In some embodiments, the plurality of busbar components further comprises a second busbar component (not shown) having a single-layer structure. In the battery 2, the expansion amounts of the battery cells 10 at different positions can be different. For the battery cell 10 with a smaller expansion amount, the second busbar component with a single-layer structure can be used; compared with the first busbar component 70, the second busbar component has a simple structure, is easy to manufacture, and can save costs. The thickness of the second busbar component is greater than the thickness of the first busbar layer 71 and the thickness of the second busbar layer 72, and the overcurrent capacity of the second busbar component can meet the requirements.

[0441] FIG. 18 is an exploded schematic view of a battery according to some embodiments of the present application.

[0442] In some embodiments, the box 20 comprises a first box wall 21 located on the upper side of the battery cell 10, and the battery cell 10 is fixed to the first box wall 21.

[0443] In some embodiments, the first box wall 21 is used as at least part of the floor of the vehicle. Using the first box wall 21 as at least part of the floor of the vehicle can save parts of the vehicle, improve the integration of the vehicle, and simplify the assembly process of the vehicle.

[0444] In some embodiments, the battery 2 further comprises a mounting beam 80, and the mounting beam 80 is arranged on the side of the first box wall 21 away from the battery cell 10.

[0445] The mounting beam 80 is connected to the first box wall 21, which can improve the overall strength of the battery 2. The mounting beam 80 can also provide mounting positions for some components of the electric device, thereby reducing parts, improving integration, and simplifying the assembly process.

[0446] In some embodiments, the mounting beam 80 is used to mount the seat of the vehicle. The embodiments of the present application can improve the space utilization of the whole vehicle. The mounting beam 80 in combination with the first box wall 21 can save more space in the vertical direction Z, so as to further increase the size of the battery monomer 10 in the vertical direction Z and improve the energy density of the battery 2.

[0447] FIG. 19 is a cross-sectional view of a negative electrode tab of a battery monomer according to some embodiments of the present application.

[0448] Referring to FIGS. 6-8 and 19, in some embodiments, a portion of the negative current collector 1121 is not covered by the negative film layer 1122. The portion of the negative current collector 1121 not covered by the negative film layer 1122 can be used to form a negative tab.

[0449] In some embodiments, the thickness of the negative current collector 1121 is 4-6 μm. For example, the thickness of the negative current collector 1121 is 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, or a range defined by any two of the above values.

[0450] In some embodiments, the compaction density of the negative film layer 1122 at 100% SOC of the battery monomer 10 is 1.15-1.36 g / cm 3 . 3

[0451] For example, the compaction density of the negative film layer 1122 at 100% SOC of the battery monomer 10 is 1.15 g / cm 3 , 1.18 g / cm 3 , 1.20 g / cm 3 , 1.22 g / cm 3 , 1.25 g / cm 3 , 1.28 g / cm 3 , 1.3 g / cm 3 , 1.32 g / cm 3 , 1.35 g / cm 3 , 1.36 g / cm 3 , or a range defined by any two of the above values.

[0452] ​For example, the compaction density of the negative electrode film layer of the battery cell 10 at 100% state of charge is defined as follows: the negative electrode film layer of the battery cell at 100% SOC is disassembled to obtain a negative electrode sheet, and the compaction density of the negative electrode film layer is measured; for example, a single-sided coated negative electrode sheet (if it is a double-sided coated negative electrode sheet, the negative electrode film layer on one side can be wiped off first) is punched into a small disc with an area of S1, weighed, and recorded as M1, and the thickness H1 is measured. Then the negative electrode film layer of the above weighed negative electrode sheet is wiped off, the weight of the negative electrode current collector is weighed and recorded as M0, and the thickness H0 is measured. The single-sided coating weight of the negative electrode film layer = (the weight of the negative electrode sheet M1-the weight of the negative electrode current collector M0) / S1, the thickness of the negative electrode film layer = the thickness of the negative electrode sheet H1-the thickness of the negative electrode current collector H0, and the compaction density of the negative electrode film layer = the single-sided coating weight of the negative electrode film layer / the thickness of the negative electrode film layer.

[0453] The compaction density of the negative electrode film layer 1122 is related to the expansion of the battery cell 10 at 100% state of charge, and the compaction density of the negative electrode film layer 1122 is limited to 1.15 g / cm 3 to 1.36 g / cm 3 , which can balance the energy density and expansion pressure of the battery cell 10 to a certain extent, reduce the deformation of the battery cell 10, and reduce the risk of connection failure between the battery cell 10 and the busbar component.

[0454] When the compaction density of the negative electrode film layer 1122 is in the above range, it is beneficial to improve the energy density of the battery cell 10; and because the negative electrode active material in the negative electrode film layer 1122 is packed more tightly, the contact resistance between particles is smaller, which can reduce the resistance of the negative electrode sheet 112, thereby reducing heat generation and improving the rapid charging capability of the battery 2.

[0455] When the compaction density of the negative electrode film layer 1122 is in the above range, the rapid charging capability of the battery cell 10 can be improved. The compaction density of the negative electrode film layer 1122 is smaller, which can increase the porosity of the negative electrode sheet 112, slow down the expansion of the negative electrode sheet, and reduce the expansion pressure of the battery cell 10.

[0456] In some embodiments, the compaction density of the negative electrode film layer 1122 of the battery cell at 100% SOC is 1.25 g / cm 3 to 1.36 g / cm 3 , which can improve the energy density of the battery cell 10.

[0457] In some embodiments, the single-sided coating weight of the negative electrode film layer 1122 is 90 mg / 1540 mm 2 to 170 mg / 1540 mm 2 . For example, the single-sided coating weight of the negative electrode film layer 1122 is 90 mg / 1540.25 mm 2, 92 mg / 15 40.25 mm 2 , 95 mg / 15 40.25 mm 2 , 96 mg / 15 40.25 mm 2 , 100 mg / 15 40.25 mm 2 , 102 mg / 15 40.25 mm 2 , 104 mg / 15 40.25 mm 2 , 105 mg / 15 40.25 mm 2 , 108 mg / 15 40.25 mm 2 , 110 mg / 15 40.25 mm 2 , 112 mg / 15 40.25 mm 2 , 114 mg / 15 40.25 mm 2 , 115 mg / 15 40.25 mm 2 , 116 mg / 15 40.25 mm 2 , 118 mg / 15 40.25 mm 2 , 120 mg / 15 40.25 mm 2 , 122 mg / 15 40.25 mm 2 , 125 mg / 15 40.25 mm 2 , 128 mg / 15 40.25 mm 2 , 130 mg / 15 40.25 mm 2 , 132 mg / 15 40.25 mm 2 , 135 mg / 15 40.25 mm 2 , 137 mg / 15 40.25 mm 2 , 140 mg / 15 40.25 mm 2 , 142 mg / 15 40.25 mm 2 , 145 mg / 15 40.25 mm 2 , 148 mg / 15 40.25 mm 2 , 150 mg / 15 40.25 mm 2 , 152 mg / 15 40.25 mm 2 , 155 mg / 15 40.25 mm 2 , 160 mg / 15 40.25 mm 2 , 165 mg / 15 40.25 mm 2 , 167 mg / 15 40.25 mm 2 , 170 mg / 15 40.25 mm 2 or a range between any two of the above values.

[0458] The single-side coating weight of the negative electrode film layer 1122 is related to the expansion of the negative electrode film layer. The single-side coating weight of the negative electrode film layer 1122 is limited to 90 mg / 1540 mm 2 to 170 mg / 1540 mm 2 , which can balance the energy density and the expansion pressure of the battery monomer 10 to some extent, reduce the deformation of the battery monomer 10, reduce the risk of connection failure of the battery monomer 10 and the busbar component, and improve the reliability.

[0459] In addition, the single-side coating weight of the negative electrode film layer 1122 is limited to 90 mg / 1540 mm 2 to 170 mg / 1540 mm 2 , which can also limit the heat generation per unit area of the negative electrode sheet 112, reduce the temperature rise of the battery monomer 10, especially during rapid charging.

[0460] In some embodiments, the single-side coating weight of the negative electrode film layer 1122 is 110 mg / 1540 mm 2 to 150 mg / 1540 mm 2 , which can further balance the energy density and the expansion pressure of the battery monomer 10.

[0461] In some embodiments, the porosity of the negative electrode sheet 112 is 27%-40%. For example, the porosity of the negative electrode sheet 112 can be 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%.

[0462] The porosity of the negative electrode sheet can be the percentage of the pore volume in the negative electrode sheet to the total volume of the negative electrode sheet. For example, when the battery monomer is at 0% state of charge, a double-sided coated negative electrode sheet is taken; the porosity of the negative electrode sheet is measured by a true density instrument AccuPyc II 1340 according to the national standard GB / T 24586-2009.

[0463] In the embodiments of the present application, the porosity of the negative electrode sheet 112 is greater than or equal to 27%, which can provide space for impurities generated by the side reaction of the negative electrode sheet 112, slow down the expansion of the negative electrode sheet 112, reduce the expansion pressure of the battery monomer 10, reduce the deformation of the battery monomer 10, improve the cycle performance of the battery monomer 10, and improve the reliability of the battery monomer 10 during rapid charging. The porosity of the negative electrode sheet 112 is less than or equal to 40%, which can balance the energy density of the battery monomer 10.

[0464] In some embodiments, the carbon-based material includes graphite particles, and the graphitization degree of the graphite particles is 92.0% to 94.5%. Illustratively, the graphitization degree of the graphite particles is 92.0%, 92.5%, 93%, 93.5%, 94%, 94.5%, or a range defined by any two of the above values.

[0465] When the graphitization degree of the graphite particles is in the above range, the graphite particles have excellent electrical conductivity, which can reduce the heat generation of the negative electrode sheet 112 and the heat generation of the battery monomer 10, and can improve the rapid charging performance of the battery monomer 10.

[0466] In some embodiments, the carbon-based material includes at least one of artificial graphite and natural graphite. Artificial graphite and natural graphite have good electrical conductivity, which can reduce the heat generation of the negative electrode sheet 112 during charging and improve the rapid charging performance of the battery monomer 10.

[0467] In some embodiments, the negative electrode active material further includes a silicon-based material. The introduction of the silicon-based material can improve the capacity of the negative electrode active material and increase the energy density of the battery monomer 10.

[0468] In some embodiments, the mass content of silicon in the silicon-based material in the negative electrode active material is 0.3% to 10%, and can be 1% to 6%. Illustratively, the mass content of silicon in the negative electrode active material is 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.2%, 8.5%, 8.8%, 9%, 9.2%, 9.5%, 9.8%, 10%, or a range defined by any two of the above values.

[0469] The introduction of the silicon-based material in the negative electrode sheet 112 can not only improve the capacity, but also increase the expansion of the negative electrode sheet 112. Therefore, by limiting the mass content of silicon in the negative electrode active material to 0.3% to 10%, the energy density and expansion of the battery monomer 10 can be considered to some extent, the deformation of the battery monomer 10 is reduced, and the cycle performance and rapid charging capability of the battery monomer 10 are improved.

[0470] The qualitative and quantitative detection of each substance or element in the present application can be carried out by using suitable equipment and methods known to those skilled in the art, and the relevant detection methods can refer to domestic and foreign detection standards, domestic and foreign enterprise standards, etc., and those skilled in the art can also adaptively change certain detection steps / instrument parameters from the perspective of detection accuracy to obtain more accurate detection results. One detection method can be used for qualitative or quantitative determination, or several detection methods can be used for qualitative or quantitative determination.

[0471] For example, the silicon-based material can be subjected to X-ray powder diffraction test and qualitative analysis by JIS / K0131-1996 X-ray Diffraction Analysis Method General Rules on the negative electrode sheet or the negative electrode active material.

[0472] In some embodiments, the silicon-based material can include at least one of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy material.

[0473] In some embodiments, the silicon-based material includes at least one of silicon oxide and silicon-carbon composite.

[0474] In some embodiments, the negative electrode active material can include at least one of tin-based material and lithium titanate in addition to the carbon-based material and the optional silicon-based material. The tin-based material can include at least one of elemental tin, tin oxide, and tin alloy material.

[0475] In some embodiments, the negative electrode film layer 1122 in the embodiments of the present application includes at least one film layer, in other words, the negative electrode film layer 1122 can adopt a single-layer film layer or at least two film layers. Alternatively, the negative electrode film layer 1122 includes at least two film layers.

[0476] In the case where the negative electrode film layer 1122 adopts a single-layer film layer, the negative electrode active material in the negative electrode film layer 1122 includes carbon-based material and optionally silicon-based material. In the case where a single-layer film layer is adopted, the volume average particle size Dv50 of the negative electrode active material is 8.2 μm to 13.5 μm. Illustratively, the volume average particle size Dv50 of the negative electrode active material is 8.2 μm, 8.5 μm, 8.8 μm, 9 μm, 9.2 μm, 9.5 μm, 9.8 μm, 10 μm, 10.2 μm, 10.5 μm, 10.8 μm, 11 μm, 11.2 μm, 11.5 μm, 11.8 μm, 12 μm, 12.2 μm, 12.5 μm, 12.8 μm, 13 μm, 13.2 μm, 13.5 μm, or a range consisting of any two of the above values.

[0477] In the case of the negative electrode film layer 1122 adopting at least two film layers, the negative electrode active material in the negative electrode film layer 1122 includes a carbon-based material, and optionally further includes a silicon-based material, which can be located in one of the at least two film layers or at least two of the at least two film layers. The negative electrode film layer 1122 can include two film layers, three film layers, four film layers, or even more film layers.

[0478] In some embodiments, the negative electrode film layer 1122 includes a first negative electrode film layer 11221 and a second negative electrode film layer 11222, and the second negative electrode film layer 11222 is arranged between the first negative electrode film layer 11221 and the negative electrode current collector 1121. The negative electrode active material includes a first negative electrode active material arranged in the first negative electrode film layer 11221 and a second negative electrode active material arranged in the second negative electrode film layer 11222, and the first negative electrode active material includes artificial graphite, and the second negative electrode active material includes one or more of artificial graphite, natural graphite, and a silicon-based material.

[0479] The interface of the first negative electrode film layer 11221 and the second negative electrode film layer 11222 can be regular or irregular; and optionally irregular.

[0480] The first negative electrode film layer 11221 and the second negative electrode film layer 11222 can be differentially arranged, so as to take into account the expansion and capacity of the negative electrode film layer 1122 to some extent; double-layer coating can construct the pore difference of the negative electrode film layer 1122, reduce the tortuosity of ion transmission, reduce side reactions, and improve the rapid charging performance of the battery monomer 10.

[0481] The artificial graphite can have a smaller volume average particle size Dv50, which on the one hand can shorten the solid-phase transmission path of lithium ions and improve the rapid charging performance, and on the other hand, the material is not easy to agglomerate during preparation, which can improve the stability of the material.

[0482] In some embodiments, the thickness ratio of the first negative electrode film layer 11221 to the second negative electrode film layer 11222 is 3:7 to 7:3. As an example, the thickness ratio of the first negative electrode film layer 11221 to the second negative electrode film layer 11222 is 3:7, 4:6, 5:5, 6:4, or 7:3.

[0483] Optionally, the thickness ratio of the first negative electrode film layer 11221 to the second negative electrode film layer 11222 is 4:6 to 6:4.

[0484] By adjusting the thickness ratio of the first negative electrode film layer 11221 to the second negative electrode film layer 11222, the gradient pore difference between the upper and lower layers can be further increased, the tortuosity of lithium ion transmission can be reduced, and the rapid charging capability of the battery monomer 10 can be improved.

[0485] In some embodiments, the thickness of the first negative electrode film layer 11221 is less than or equal to the thickness of the second negative electrode film layer 11222, which can further improve the rapid charging capability of the battery cell 10.

[0486] In some embodiments, the first negative electrode active material is particulate, and the second negative electrode active material is particulate.

[0487] In some embodiments, the volume average particle size Dv50 of the first negative electrode active material is less than or equal to the volume average particle size Dv50 of the second negative electrode active material. Further optionally, the volume average particle size Dv50 of the first negative electrode active material is less than the volume average particle size Dv50 of the second negative electrode active material.

[0488] The difference in particle size of the first negative electrode active material and the second negative electrode active material can improve the rapid charging performance of the battery cell 10. During rapid charging, the overpotential of the first negative electrode film layer 11221 is usually high, and the bottleneck of rapid charging is mainly in the first negative electrode film layer 11221. In the present application, the particle size of the first negative electrode active material is relatively small, which can shorten the solid-phase transmission path of ions, improve the rapid charging performance, and improve the problem of ion precipitation on the surface of the negative electrode sheet 112. The particle size of the second negative electrode active material is relatively large, which can form larger pores in the second negative electrode film layer 11222. During charging, the pores can absorb expansion, reduce the expansion amount of the negative electrode film layer 1122, and improve the reliability of the battery cell 10 during rapid charging.

[0489] In some embodiments, the volume average particle size Dv50 of the first negative electrode active material is 7.8 μm-14.3 μm, which can be 7.8 μm-11.3 μm. Illustratively, the volume average particle size Dv50 of the first negative electrode active material is 7.8 μm, 8.0 μm, 8.2 μm, 8.5 μm, 8.8 μm, 9 μm, 9.2 μm, 9.5 μm, 9.8 μm, 10 μm, 10.2 μm, 10.5 μm, 10.8 μm, 11 μm, 11.3 μm, 11.2 μm, 11.5 μm, 11.8 μm, 12 μm, 12.2 μm, 12.5 μm, 12.8 μm, 13 μm, 13.2 μm, 13.5 μm, 13.8 μm, 14 μm, 14.1 μm, 14.3 μm, or a range formed by any two of the above values.

[0490] The volume average particle size Dv50 of the first negative electrode active material is set to 7.8 μm-14.3 μm, which can shorten the solid-phase transmission path of lithium ions, improve the rapid charging performance, on the one hand; on the other hand, the material is not easy to agglomerate during preparation, which can improve the stability of the material; on the other hand, the first negative electrode active material with the above volume average particle size range can cooperate with the second negative electrode active material, which is beneficial to build a gradient pore difference of the first negative electrode film layer 11221 and the second negative electrode film layer 11222, reduce the tortuosity of lithium ion transmission, and improve the rapid charging performance of the battery monomer 10.

[0491] The volume average particle size Dv50 of the material refers to the particle size corresponding to 50% of the volume distribution, and the volume average particle size Dv10 of the material refers to the particle size corresponding to 10% of the volume distribution, which can be detected by using devices and methods known in the art, for example, taking the negative electrode active material as a sample, and testing the Dv50 and Dv10 of the particles by a Mastersizer 2000E laser particle size analyzer according to the test standard GB / T 19077-2016.

[0492] In some embodiments, the volume average particle size Dv50 of the second negative electrode active material is 9.5 μm-18.5 μm, which can be optionally 9.5 μm-14.6 μm.

[0493] Exemplarily, the volume average particle size Dv50 of the second negative electrode active material is 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 14.6 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm, or a range formed by any two of the above values.

[0494] The volume average particle size Dv50 of the second negative electrode active material is 9.5 μm-18.5 μm, which can make the pores of the second negative electrode film layer 11222 more abundant, which is beneficial to improve the rapid charging capacity of the battery monomer 10 and reduce the expansion of the negative electrode film layer 1122 during charging.

[0495] In some embodiments, the first negative electrode active material includes graphite particles, and the volume average particle size Dv50 of the graphite particles in the first negative electrode film layer 11221 is 7.8 μm to 14.3 μm, which can be optionally 7.8 μm to 11.3 μm. Optionally, the first negative electrode active material includes artificial graphite.

[0496] The second negative electrode active material includes graphite particles, and the volume average particle size Dv50 of the graphite particles is 9.5 μm to 18.5 μm, which can be optionally 9.5 μm to 14.6 μm. Optionally, the second negative electrode active material includes natural graphite.

[0497] In some embodiments, the specific surface area of ​​the negative electrode active material is 0.5 m². 2 / g-3m 2 / g, optional 0.6m 2 / g-1.2m 2 / g. For example, the specific surface area of ​​the negative electrode active material is 0.5m². 2 / g, 0.6m 2 / g, 0.7m 2 / g, 0.8m 2 / g, 0.9m 2 / g, 1.0m 2 / g, 1.1m 2 / g, 1.2m 2 / g, 1.3m 2 / g, 1.4m 2 / g, 1.5m 2 / g, 1.6m 2 / g, 1.7m 2 / g, 1.8m 2 / g, 1.9m 2 / g, 2.0m 2 / g、2.1m 2 / g, 2.2m 2 / g, 2.3m 2 / g, 2.4m 2 / g, 2.5m 2 / g, 2.6m 2 / g, 2.7m 2 / g, 2.8m 2 / g, 2.9m 2 / g, 3.0m 2 / g or a range consisting of any two of the above values.

[0498] The specific surface area of ​​a material is a well-known concept in the art and can be tested using equipment and methods known in the art. For example, it can be tested according to the testing standard GB / T 19587-2017, using the negative electrode active material as a sample and testing the specific surface area using a Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, Inc.

[0499] In this application embodiment, the specific surface area of ​​the negative electrode active material is limited to greater than or equal to 0.5 m². 2 / g can improve the fast charging capability of a single battery cell; the specific surface area of ​​the negative electrode active material is limited to less than or equal to 3m². 2 / g can reduce the side reactions of the battery cell 10 during storage, slow down the expansion of the negative electrode, and reduce the expansion pressure.

[0500] In some embodiments, the lithium-containing olivine-structured phosphate has a chemical formula of LiFe 1-x-y Mn x M y PO4, 0≤x≤1, 0≤y<1, M is selected from one or more of V, Nb, Ti, Co, Ni, Sc, Ge, Mg, Al, Zr, Mn, Hf, Ta, Mo, W, Ru, Ag, Sn, and Pb.

[0501] In some embodiments, the lithium-containing olivine-structured phosphate or the modified material thereof can be a lithium-containing olivine-structured phosphate or a material obtained after coating modification. For example, the lithium-containing olivine-structured phosphate includes phosphate particles and an ion-conductive layer, the ion-conductive layer is coated on the surface of the phosphate particles, and the ion-conductive layer contains one or more elements of C, Fe, Ti, Zr, Hf, Ge, and Sn.

[0502] In some embodiments, the mass percentage of the lithium-containing olivine-structured phosphate or the modified material thereof in the positive electrode active material can be greater than or equal to 80% and less than or equal to 100%, and the positive electrode active material of the present application can be considered as a lithium-containing olivine-structured phosphate or a modified material thereof system. When the mass percentage of the lithium-containing olivine-structured phosphate or the modified material thereof is less than 100%, the positive electrode active material can further include commonly used positive electrode active materials, for example, can include but is not limited to at least one of lithium-containing transition metal oxides. Examples of lithium-containing transition metal oxides can include but are not limited to at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and a modified compound of each thereof.

[0503] Optionally, the mass percentage of the lithium-containing olivine-structured phosphate or the modified material thereof in the positive electrode active material is 100%.

[0504] In some embodiments, the compaction density of the positive electrode film layer 1112 of the battery cell at 100% SOC is 2.50 g / cm 3 to 2.80 g / cm 3 ; optionally 2.55 g / cm 3 to 2.70 g / cm 3 .

[0505] Illustratively, the compaction density of the positive electrode film layer 1112 of the battery cell 10 at 100% state of charge SOC is 2.50 g / cm 3 , 2.52 g / cm 3 , 2.55 g / cm 3 , 2.56 g / cm 3 , 2.57 g / cm3 2.58 g / cm3 3 2.60 g / cm3 3 2.62 g / cm3 3 2.65 g / cm3 3 2.68 g / cm3 3 2.30 g / cm3 3 2.32 g / cm3 3 2.75 g / cm3 3 2.78 g / cm3 3 2.80 g / cm3 3 or a range between any two of the above values.

[0506] When the compaction density of the positive electrode film layer 1112 is within the above range, the energy density of the battery monomer 10 can be improved. In addition, the positive electrode active material in the positive electrode film layer 1112 is closely packed, and the contact resistance between particles is small, which can further reduce the resistance of the positive electrode sheet 111, thereby reducing the heat generation under fast charging.

[0507] In the embodiments of the present application, the compaction density of the positive electrode film layer 1112 at 100% SOC of the battery monomer 100 is a meaning known in the art, that is, the positive electrode sheet 111 is disassembled from the battery monomer 10 at 100% SOC, and the compaction density of the positive electrode film layer 1112 is measured. Exemplarily, the test method of the compaction density of the positive electrode film layer 1112 can be the same as the test method of the compaction density of the negative electrode film layer 1122.

[0508] In some embodiments, the single-sided coating weight of the positive electrode film layer 1112 is 200 mg / 1540 mm 2 370 mg / 1540 / mm 2 ; and can be 240 mg / 1540 mm 2 to 330 mg / 1540 mm 2 .

[0509] Exemplarily, the single-sided coating weight of the positive electrode film layer 1112 is 200 mg / 1540.25 mm 2 210 mg / 1540.25 mm 2 220 mg / 1540.25 mm 2 230 mg / 1540.25 mm 2 240 mg / 1540.25 mm 2 250 mg / 1540.25 mm 2 260 mg / 1540.25 mm 2 270 mg / 1540.25 mm 2 280 mg / 1540.25 mm2 290 mg / 1540.25 mm 2 300 mg / 1540.25 mm 2 310 mg / 1540.25 mm 2 320 mg / 1540.25 mm 2 330 mg / 1540.25 mm 2 340 mg / 1540.25 mm 2 350 mg / 1540.25 mm 2 360 mg / 1540.25 mm 2 370 mg / 1540.25 mm 2 or a range between any two of the above values.

[0510] In the embodiments of the present application, the single-side coating weight of the positive electrode film layer 1112 is the meaning known in the art, which can be detected by using the devices and methods known in the art, and the detection method is as follows.

[0511] The single-side coating weight of the positive electrode film layer 1112 is set to 200 mg / 1540 mm 2 - 370 mg / 1540 / mm 2 The heat production per unit area of the positive electrode sheet 111 can be limited, and the energy density and the charge rate performance of the battery monomer 10 can be improved.

[0512] In some embodiments, the porosity of the positive electrode sheet 111 is 25%-32%. As an example, the porosity of the positive electrode sheet 111 can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32% or a range between any two of the above values.

[0513] In the embodiments of the present application, the porosity of the positive electrode sheet 111 is the meaning known in the art, which can be detected by using the devices and methods known in the art, and the detection method is as follows.

[0514] The porosity of the positive electrode sheet 111 is greater than or equal to 25%, which can provide space for impurities generated by side reactions of the positive electrode sheet 111, reduce the swelling pressure of the battery monomer, reduce the deformation of the battery monomer 10, and improve the cycle performance of the battery monomer 10. The porosity of the positive electrode sheet 111 is less than or equal to 32%, which can improve the energy density of the battery monomer 10 to a certain extent.

[0515] In some embodiments, the thickness of the positive electrode sheet 111 can be 0.13 mm-0.2 mm. For example, the thickness of the positive electrode sheet 111 can be 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, or a range defined by any two of the above values.

[0516] In the embodiments of the present application, the thickness of the positive electrode sheet 111 has the meaning known in the art and can be detected by using the devices and methods known in the art, for example, using a micrometer to measure the thickness of the positive electrode sheet 111.

[0517] Using the positive electrode sheet 111 with a smaller thickness can shorten the ion migration path, improve the ion migration rate, reduce the heat generation of the battery monomer 10, and improve the rapid charging performance of the battery monomer 10.

[0518] In some embodiments, the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 is 0.05-0.3. For example, in the embodiments of the present application, the thickness of the positive electrode film layer 1112 is the thickness of the positive electrode film layer 1112 on one side of the positive electrode current collector 1111.

[0519] For example, the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 is 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, or a range defined by any two of the above values.

[0520] Limiting the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 to be greater than or equal to 0.05 can improve the flow capacity of the positive electrode current collector 1111, reduce the temperature rise of the positive electrode sheet 111, and improve the rapid charging performance of the battery monomer 10. Limiting the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 to be less than or equal to 0.3 can reduce the loss of capacity of the positive electrode sheet 111. The embodiments of the present application limit the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 to be 0.05-0.3, which can balance the rapid charging performance and energy density of the battery monomer 10 to a certain extent.

[0521] The thickness of the positive electrode film layer and the thickness of the positive electrode current collector are well known in the art, and can be detected using well known devices and methods in the art, for example, the thickness of the positive electrode sheet can be measured using a micrometer, the thickness of the positive electrode current collector can be measured after removing the film layer on the surface of the positive electrode current collector, when the positive electrode film layer is coated on one side, the thickness of the positive electrode film layer is the thickness of the positive electrode sheet minus the thickness of the positive electrode current collector; when the positive electrode film layer is coated on both sides, the thickness of the positive electrode film layer is (the thickness of the positive electrode sheet minus the thickness of the positive electrode current collector) / 2.

[0522] In some embodiments, the thickness of the positive electrode current collector 1111 is 10 μm to 15 μm, and can be 12 μm to 15 μm. For example, the thickness of the positive electrode current collector 1111 is 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, or a range defined by any two of the above values. When the thickness of the positive electrode current collector 1111 is in the above range, the positive electrode current collector 1111 has excellent flow capacity, and the battery cell 10 has high energy density.

[0523] In some embodiments, a portion of the positive electrode current collector 1111 is not covered by the positive electrode film layer 1112; the portion of the positive electrode current collector 1111 not covered by the positive electrode film layer 1112 can be used to form a positive electrode tab.

[0524] In some embodiments, the volume average particle size of the positive electrode active material satisfies 1 μm≤Dv50≤2 μm, and 0.4 μm≤Dv10≤0.7 μm.

[0525] For example, the Dv50 of the positive electrode active material can be 1 μm, 1.1 μm, 1.15 μm, 1.2 μm, 1.25 μm, 1.3 μm, 1.35 μm, 1.4 μm, 1.45 μm, 1.5 μm, 1.55 μm, 1.6 μm, 1.65 μm, 1.7 μm, 1.75 μm, 1.8 μm, 1.85 μm, 1.9 μm, 1.95 μm, 2 μm, or a range defined by any two of the above values.

[0526] For example, the Dv10 of the positive electrode active material can be 0.4 μm, 0.45 μm, 0.5 μm, 0.55 μm, 0.6 μm, 0.65 μm, 0.7 μm, or a range defined by any two of the above values.

[0527] The particle size of the positive electrode active material is relatively small, the lithium ion has a short deintercalation lithium path in the positive electrode active material, and the heat generation is less; and the particle size of the positive electrode active material is not too small, which can reduce agglomeration during processing and preparation, and the performance of the positive electrode active material is stable.

[0528] The volume average particle size Dv50 of the material refers to the particle size corresponding to 50% of the volume distribution, and the volume average particle size Dv10 of the material refers to the particle size corresponding to 10% of the volume distribution, which can be detected by using devices and methods known in the art. For example, the positive electrode active material is taken as a sample, and the Dv50 and Dv10 of the particles are tested by a Mastersizer 2000E laser particle size analyzer according to the test standard GB / T 19077-2016.

[0529] In some embodiments, the battery cell 10 comprises an electrolyte contained in the shell 12. During the charging and discharging of the battery cell 10, active ions are embedded and extracted between the positive electrode sheet 111 and the negative electrode sheet 112, and the electrolyte plays a role in conducting the active ions between the positive electrode sheet 111 and the negative electrode sheet 112.

[0530] In some embodiments, the electrolyte has an electrical conductivity of 13 mS / cm to 20 mS / cm, which can be 15 mS / cm to 20 mS / cm, at room temperature (for example, 25°C). For example, the electrolyte has an electrical conductivity of 13 mS / cm, 13.5 mS / cm, 14 mS / cm, 14.5 mS / cm, 15 mS / cm, 15.5 mS / cm, 16 mS / cm, 16.5 mS / cm, 17 mS / cm, 17.5 mS / cm, 18 mS / cm, 18.5 mS / cm, 19 mS / cm, 19.5 mS / cm, 20 mS / cm, or a range formed by any two of the above values.

[0531] When the electrolyte has an electrical conductivity in the above range, the migration rate of ions in the electrolyte is high, thereby further reducing the internal resistance of the battery cell 10, reducing heat generation, and improving the rapid charging performance of the battery cell 10.

[0532] The electrical conductivity of the electrolyte is the ionic conductivity, which can be detected by using devices and methods known in the art, for example, by referring to the industry standard HG-T 4067-2015.

[0533] In some embodiments, the density p of the electrolyte at room temperature (for example, 25°C) satisfies: 1.05 g / mL≤p≤1.35 g / mL.

[0534] For example, the density p of the electrolyte is 1.05 g / mL, 1.10 g / mL, 1.15 g / mL, 1.2 g / mL, 1.25 g / mL, 1.3 g / mL, 1.35 g / mL, or a range formed by any two of the above values.

[0535] When the density p of the electrolyte is in the above range, the migration rate of lithium ions in the electrolyte is high, which can further reduce the internal resistance of the battery monomer 10, thereby reducing the heat generation, and can improve the rapid charging performance of the battery monomer 10.

[0536] In the embodiments of the present application, the density of the electrolyte is the meaning known in the art, which can be detected by using the devices and methods known in the art, for example, tested according to GB / T 2013-2010.

[0537] In some embodiments, the electrolyte comprises an organic solvent, and the organic solvent comprises one or more of a carbonate-based solvent and a carboxylate-based solvent.

[0538] In some embodiments, the carboxylate-based solvent comprises a chain carboxylate-based solvent, and the mass content of the chain carboxylate-based solvent in the organic solvent is 5% to 75%. Illustratively, the mass content of the chain carboxylate-based solvent is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or a range formed by any two of the above values. When the mass content of the chain carboxylate-based solvent is in the above range, the viscosity of the electrolyte system is relatively small, which is beneficial to the migration of lithium ions.

[0539] In some embodiments, the mass content of the chain carboxylate-based solvent in the organic solvent is 30% to 70%.

[0540] In some embodiments, the carboxylate comprises R1-COO-R2, and R1 and R2 each independently comprises an alkyl group with 1-5 carbon atoms or a halogenated alkyl group with 1-5 carbon atoms. The above chain carboxylate-based solvent has a high electrical conductivity, which is beneficial to improving the rapid charging capability of the battery monomer 10.

[0541] In some embodiments, the carbonate-based solvent comprises one or more of vinyl carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0542] Further optionally, the carbonate-based solvent comprises one or more of vinyl carbonate, dimethyl carbonate, and methyl ethyl carbonate.

[0543] The above carbonate-based solvent and chain carboxylate-based solvent are used in combination, so that the electrical conductivity of the electrolyte is improved, which is beneficial to the migration of lithium ions.

[0544] Further optionally, the mass content of the carbonate-based solvent in the organic solvent is 5% to 95%, optionally 25% to 60%, optionally 30% to 45%. Illustratively, the mass content of the carbonate-based solvent in the organic solvent is 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 40%, 45%, 48%, 50%, 55%, 60%, or a range between any two of the foregoing values. The carbonate-based solvent in the above mass content can further improve the conductivity of the electrolyte, which is conducive to the migration of lithium ions.

[0545] Illustratively, the carbonate-based solvent includes one or more of ethylene carbonate, dimethyl carbonate, and methyl ethyl carbonate, and the mass content of the carbonate-based solvent is 25% to 60%.

[0546] The organic solvent can improve the conductivity and reduce the viscosity of the electrolyte, thereby improving the rapid charging performance of the battery.

[0547] In some embodiments, the electrolyte includes a lithium salt. The lithium salt includes one or more of a fluorine-containing sulfimide salt and lithium hexafluorophosphate LiPF6. The above lithium salt is easy to dissociate, which is conducive to the rapid migration of lithium ions; and the electrolyte system is relatively stable and is not easy to decompose, which can improve the cycle performance of the battery cell.

[0548] Optionally, the fluorine-containing sulfimide salt includes one or more of lithium bisfluorosulfimide LiFSI and lithium bis-trifluoromethylsulfonylimide LiTFSI.

[0549] In some embodiments, the lithium salt includes lithium bisfluorosulfimide LiFSI and lithium hexafluorophosphate LiPF6, the molar concentration of lithium bisfluorosulfimide LiFSI is 0.2 mol / L to 0.5 mol / L, and the molar concentration of lithium hexafluorophosphate LiPF6 is 0.5 mol / L to 1.0 mol / L. Illustratively, the molar concentration of lithium bisfluorosulfimide LiFSI is 0.4 mol / L to 0.5 mol / L, and the molar concentration of lithium hexafluorophosphate LiPF6 is 0.7 mol / L. Illustratively, the molar concentration of lithium bisfluorosulfimide LiFSI is 0.5 mol / L, and the molar concentration of lithium hexafluorophosphate LiPF6 is 0.5 mol / L. Illustratively, the molar concentration of lithium bisfluorosulfimide LiFSI is 0.2 mol / L, and the molar concentration of lithium hexafluorophosphate LiPF6 is 0.8 mol / L.

[0550] Optionally, the ratio of the molar concentration of lithium bisfluorosulfonylimide to the molar concentration of lithium hexafluorophosphate LiPF6 is (2 to 5):10. Illustratively, the ratio of the molar concentration of lithium bisfluorosulfonylimide to the molar concentration of lithium hexafluorophosphate LiPF6 is 2:10, 2.5:10, 3:10, 3.5:10, 4:10, 4.5:10, 5:10, or a range defined by any two of the aforementioned values.

[0551] According to some embodiments of the present application, the present application also provides a power consuming device comprising the battery 2 of any of the above embodiments, the battery 2 being configured to provide power for the power consuming device. The power consuming device can be any of the devices or systems mentioned above.

[0552] Referring to FIGS. 2-5, the embodiments of the present application provide a battery 2 comprising a box body 20, a plurality of battery cell groups 100 and a plurality of heat exchange members 30, the plurality of battery cell groups 100 and the plurality of heat exchange members 30 being accommodated in the box body 20.

[0553] The box body 20 comprises a first box wall 21, a second box wall 22 and a frame 23, the first box wall 21 and the second box wall 22 being oppositely arranged along a vertical direction Z, the frame 23 connecting the first box wall 21 and the second box wall 22, the first box wall 21 being located above the second box wall 22, and the first box wall 21, the second box wall 22 and the frame 23 enclosing a containing space.

[0554] Each battery cell group 100 comprises at least two battery cells 10 arranged along a first direction Y, and the plurality of battery cell groups 100 are arranged along a thickness direction X of the battery cell 10.

[0555] Each two battery cell groups 100 are provided with one heat exchange member 30.

[0556] The battery cell 10 comprises an outer shell 12, an electrode assembly 11 and a pressure relief mechanism 15, the outer shell 12 comprising a first end wall 12a and a second end wall 12b, the first end wall 12a being located on a side of the electrode assembly 11 facing the second box wall 22 and being spaced apart from the second box wall 22, and the second end wall 12b being located on a side of the electrode assembly 11 facing the first box wall 21 and being bonded to the first box wall 21.

[0557] The outer shell 12 comprises two first side walls 12d and two second side walls 12e.

[0558] The two first side walls 12d are oppositely arranged along the thickness direction X of the battery cell 10; and each first side wall 12d connects the first end wall 12a and the second end wall 12b.

[0559] Two second side walls 12e are arranged opposite to each other along a first direction Y perpendicular to the thickness direction X; each second side wall 12e connects two first side walls 12d. Each second side wall 12e connects the first end wall 12a and the second end wall 12b.

[0560] One first side wall 12d of the battery cell 10 is connected to and exchanges heat with the heat exchange member 30. The pressure relief mechanism 15 is arranged at the first end wall 12a.

[0561] The electrode assembly 11 comprises a positive electrode sheet 111, a negative electrode sheet 112 and a separator 113 between the positive electrode sheet 111 and the negative electrode sheet 112, the positive electrode sheet 111 comprises a positive electrode current collector 1111 and a positive electrode film layer 1112 arranged on at least one side of the positive electrode current collector 1111, the positive electrode film layer 1112 comprises a positive electrode active material, and the positive electrode active material comprises a lithium-containing phosphate with an olivine structure; the negative electrode sheet 112 comprises a negative electrode current collector 1121 and a negative electrode film layer 1122 arranged on at least one side of the negative electrode current collector 1121, the negative electrode film layer 1122 comprises a negative electrode active material, and the negative electrode active material comprises a carbon-based material.

[0562] The charging time of the battery cell 10 from 10% SOC to 80% SOC at room temperature can be 5 min to 10.5 min.

[0563] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0564] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery, comprising: a case; a battery cell accommodated in the case, the battery cell comprising a shell and an electrode assembly accommodated in the shell, the shell comprising two first side walls oppositely arranged along a thickness direction of the battery cell; and a heat exchange member arranged on at least one side of the battery cell along the thickness direction and configured to exchange heat with the first side walls; wherein the electrode assembly comprises a positive electrode sheet, a negative electrode sheet, and a separator film between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises a lithium-containing phosphate with an olivine structure, the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side of the negative electrode current collector, the negative electrode film layer comprises a negative electrode active material, and the negative electrode active material comprises a carbon-based material; the battery cell has a charging time of 5 minutes to 10.5 minutes from 10% SOC to 80% SOC at room temperature. The one first side wall of the battery cell is connected to the heat exchange member. 4.The battery of any one of claims 1-3, comprising a plurality of battery cell groups and a plurality of heat exchange members, the plurality of battery cell groups are arranged along the thickness direction, and each of the battery cell groups comprises at least two battery cells arranged along a direction perpendicular to the thickness direction. One heat exchange member is arranged between every two battery cell groups. The heat exchange member is bonded to the first side wall by a first adhesive layer.

2. The battery of claim 1, wherein, The heat exchange member comprises a heat conduction plate, and the heat conduction plate is internally provided with a flow channel for arranging a heat exchange medium.

3. The battery according to claim 1 or 2, wherein The heat exchange member further comprises an insulating layer, and at least part of the insulating layer is arranged between the heat conduction plate and the first side wall. The thermal conductivity of the insulating layer is greater than or equal to 0.1 W / (m·K). The shell further comprises a first end wall and a second end wall oppositely arranged, and the first side wall connects the first end wall and the second end wall.

5. The battery of any one of claims 1-4, wherein, The first end wall is located at the lower side of the electrode assembly, and the second end wall is located at the upper side of the electrode assembly and connected to the case.

6. The battery of any one of claims 1-5, wherein, The second end wall is bonded to the case.

7. The battery of claim 6, wherein, The battery cell further comprises a pressure relief mechanism arranged on the first end wall.

8. The battery of claim 7, wherein, The shell further comprises a first end wall connecting the two first side walls.

9. The battery of any one of claims 1-8, wherein, The battery cell further comprises a first electrode terminal arranged on the first end wall, and the electrode assembly comprises an electrode body and a first tab extending from the electrode body, and the first electrode terminal is electrically connected to the first tab. The first end wall has an inner surface facing the electrode assembly, and in a direction close to the electrode assembly, the first electrode terminal does not exceed the inner surface.

10. The battery of claim 9, wherein, The first electrode terminal comprises a connecting portion provided with a through hole, and the first tab is arranged in the through hole, and part of the first tab is located on a side of the connecting portion away from the electrode body and connected to the connecting portion.

11. The battery of claim 9 or 10, wherein, ​ 12. The battery of any one of claims 1-11, wherein, ​ ​ 13. The battery of claim 12, wherein, The area of the orthographic projection of the portion of the first electrode terminal located outside the first end wall onto the first end wall is 200 mm 2 - 600 mm 2 .

14. The battery of claim 12 or 13, wherein, ​ 15. The battery of any one of claims 12-14, wherein, ​ 16. The battery of claim 15, wherein, The first electrode terminal includes a terminal body and a cover plate, the terminal body is fixed to the first end wall, a recess is arranged on the side of the terminal body away from the electrode body, and the bottom wall of the recess is the connecting portion; The cover plate is arranged on the side of the connecting portion away from the electrode body and covers the recess.

17. The battery of claim 16, wherein, At least part of the cover plate is accommodated in the recess.

18. The battery of any one of claims 12-17, wherein, In the width direction of the first end wall, the size of the first end wall is W1 mm, and the size of the part of the first electrode terminal outside the first end wall is W2 mm; W2 and W1 satisfy: 0.4≤W2 / W1≤1.

19. The battery of any one of claims 1-18, wherein, The box body includes a first box wall on the upper side of the battery cell, and the battery cell is fixed to the first box wall.

20. The battery of claim 19, wherein, The first box wall is used as at least part of the floor of the vehicle.

21. The battery according to claim 19 or 20, further comprising a mounting beam arranged on the side of the first box wall away from the battery cell.

22. The battery of claim 21, wherein, The mounting beam is used to mount the seat of the vehicle.

23. The battery of any one of claims 1-22, wherein, The box body includes a second box wall arranged on the lower side of the battery cell.

24. The battery of claim 23, wherein, The second box wall is arranged spaced apart from the battery cell.

25. The battery according to any one of claims 1-24, further comprising a support arranged on the lower side of the housing and used to support the housing.

26. The battery of claim 25, wherein, The box body includes a second box wall arranged on the lower side of the battery cell; The support is bonded to the housing and the second box wall.

27. The battery of claim 26, wherein, The elastic modulus of the support is less than the elastic modulus of the second box wall.

28. The battery of claim 25, wherein, The box body includes a plurality of limiting beams arranged spaced apart in the thickness direction of the battery cell, and a plurality of battery cells are arranged between adjacent limiting beams; The support connects adjacent limiting beams.

29. The battery of claim 28, wherein, The support includes a metal strip and an insulating film covering the metal strip, and the insulating film separates the metal strip from the first end wall.

30. The battery of claims 25-29, wherein, The support has a cavity inside.

31. The battery of any one of claims 1-30, wherein, The battery cell further includes a sampling member arranged on the housing, and the sampling member is used to collect the temperature of the housing.

32. The battery of any one of claims 1-31, wherein, The expansion pressure of the battery cell in the thickness direction thereof is 0.5 MPa-2.4 MPa.

33. The battery according to any one of claims 1-32, comprising a plurality of battery cells and a plurality of busbar components, the plurality of busbar components electrically connecting the plurality of battery cells; The plurality of busbar components includes at least one first busbar component, the first busbar component includes a first busbar layer and a second busbar layer stacked and connected, and the first busbar layer electrically connects at least two battery cells arranged in the thickness direction.

34. The battery of claim 33, wherein, The first busbar component includes at least one bending portion connecting the first busbar layer and the second busbar layer.

35. The battery according to claim 34, wherein The first busbar layer includes a first busbar portion, a second busbar portion, and a first buffer portion connecting the first busbar portion and the second busbar portion, the first busbar portion and the second busbar portion are arranged in the thickness direction and connected to different battery cells. The second busbar layer comprises a first layer, a second layer, and a second buffer part, the first layer is stacked with the first busbar and connected by at least one bending part, and the second layer is stacked with the second busbar and connected by at least one bending part.

36. The battery of any one of claims 1-35, wherein, The box comprises a plurality of limiting beams, which are arranged in the thickness direction of the battery monomer, and a plurality of battery monomers are arranged between adjacent limiting beams. In the thickness direction, the distance between two adjacent limiting beams is D1, and the sum of the sizes of all electrode assemblies stacked in the thickness direction between two adjacent limiting beams is D2. 85%≤D2 / D1≤92%.

37. The battery of any one of claims 1-36, wherein, The single-side coating weight of the negative electrode film layer is 90 mg / 1540 mm 2 to 170 mg / 1540 mm 2 , optionally 110 mg / 1540 mm 2 to 150 mg / 1540 mm 2 .

38. The battery of any one of claims 1-37, wherein, The compaction density of the negative electrode film layer at 100% SOC of the battery cell is 1.15 g / cm 3 to 1.36 g / cm 3 , optionally 1.25 g / cm 3 to 1.36 g / cm 3 .

39. The battery of any one of claims 1-38, wherein, The porosity of the negative electrode sheet is 27%-40%.

40. The battery of any one of claims 1-39, wherein, The carbon-based material comprises at least one of artificial graphite and natural graphite.

41. The battery of any one of claims 1-40, wherein, The silicon-based material in the negative electrode active material has a mass content of 0.3%-10% of silicon element in the negative electrode active material, and optionally 1%-6%.

42. The battery of claim 41, wherein, The silicon-based material comprises at least one of silicon oxide and silicon-carbon composite.

43. The battery of any one of claims 1-42, wherein, The negative electrode film layer comprises a first negative electrode film layer and a second negative electrode film layer, and the second negative electrode film layer is arranged between the first negative electrode film layer and the negative electrode current collector. The negative electrode active material comprises a first negative electrode active material arranged in the first negative electrode film layer and a second negative electrode active material arranged in the second negative electrode film layer, the first negative electrode active material comprises artificial graphite, and the second negative electrode active material comprises one or more of artificial graphite, natural graphite and silicon-based material.

44. The battery of claim 43, wherein, The thickness ratio of the first negative electrode film layer to the second negative electrode film layer is 3:7-7:3, and optionally 4:6-6:

4.

45. The battery of claim 43 or 44, wherein, The thickness of the first negative electrode film layer is less than or equal to the thickness of the second negative electrode film layer.

46. The battery of any one of claims 43-45, wherein, The volume average particle size Dv50 of the first negative electrode active material is less than or equal to the volume average particle size Dv50 of the negative electrode active material.

47. The battery of any one of claims 43-46, wherein, The volume average particle size Dv50 of the first negative electrode active material is 7.8 μm-14.3 μm, and optionally 7.8 μm-11.3 μm. The volume average particle size Dv50 of the second negative electrode active material is 9.5 μm-18.5 μm, and optionally 9.5 μm-14.6 μm.

48. The battery of any one of claims 1-47, wherein, The specific surface area of the negative active material is 0.5 m 2 / g-3 m 2 / g, optionally 0.6 m 2 / g-1.2 m 2 / g.

49. The battery of any one of claims 1-48, wherein, The lithium-containing phosphate of olivine structure has the chemical formula LiFe 1-x-y Mn x M y PO4, 0≤x≤1, 0≤y<1, M is selected from one or more of V, Nb, Ti, Co, Ni, Sc, Ge, Mg, Al, Zr, Mn, Hf, Ta, Mo, W, Ru, Ag, Sn, and Pb.

50. The battery of any one of claims 1-49, wherein, The single-side coating weight of the positive electrode film layer is 200 mg / 1540 mm 2 - 370 mg / 1540 / mm 2 ; optionally 240 mg / 1540 mm 2 to 330 mg / 1540 mm 2 .

51. The battery of any one of claims 1-50, wherein, The positive electrode film layer has a compacted density of 2.50 g / cm 3 to 2.80 g / cm 3 ; optionally 2.55 g / cm 3 - 2.70 g / cm 3 at 100% SOC of the battery cell.

52. The battery of any one of claims 1-51, wherein, The porosity of the positive electrode sheet is 25%-32%.

53. The battery of any one of claims 1-52, wherein, The thickness of the positive electrode sheet is 0.13 mm-0.2 mm.

54. The battery of any one of claims 1-53, wherein, The ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer is 0.05-0.

3.

55. The battery of any one of claims 1-54, wherein, The volume average particle size of the positive electrode active material satisfies 1 μm≤Dv50≤2 μm, and 0.4 μm≤Dv10≤0.7 μm.

56. The battery of any one of claims 1-55, wherein, The battery monomer comprises an electrolyte contained in the shell.

57. The battery of claim 56, wherein, The conductivity of the electrolyte at room temperature is 15 mS / cm-20 mS / cm.

58. The battery of claim 56 or 57, wherein, The electrolyte comprises an organic solvent, and the organic solvent comprises one or more of carbonate solvents and carboxylate solvents.

59. The battery of claim 58, wherein, The carbonate solvents comprise one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate.

60. The battery of claim 58 or 59, wherein, The carboxylic acid ester includes R1-COO-R2, R1 and R2 each independently include alkyl of 1-5 carbon atoms or halogenated alkyl of 1-5 carbon atoms.

61. The battery of any one of claims 56-60, wherein, The electrolyte includes a lithium salt, the lithium salt includes lithium bisfluorosulfonylimide LiFSI and lithium hexafluorophosphate LiPF6, the molar concentration of the lithium bisfluorosulfonylimide LiFSI is 0.2-0.5 mol / L, and the molar concentration of the lithium hexafluorophosphate LiPF6 is 0.5-1.0 mol / L.

62. The battery of any one of claims 56-61, wherein, The density ρ of the electrolyte at room temperature satisfies: 1.05 g / mL≤ρ≤1.35 g / mL.

63. An electric device comprising the battery of any one of claims 1-62, the battery being used to provide electric energy.

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