Battery cell and electric equipment

Abstract

The embodiment of the invention provides a battery cell and electric equipment, the battery cell comprises an electrode assembly, the electrode assembly comprises a positive pole piece and a negative pole piece, the positive pole piece comprises a plurality of first positive pole tabs and a plurality of second positive pole tabs, and the negative pole piece comprises a plurality of first negative pole tabs and a plurality of second negative pole tabs; the first positive pole lug and the first negative pole lug are positioned at one end of the electrode assembly along the length direction, and the second positive pole lug and the second negative pole lug are positioned at the other end of the electrode assembly along the length direction. In the thickness direction of the electrode assembly, the projection of the first positive pole lug and the projection of the first negative pole lug are at least partially overlapped, and the projection of the second positive pole lug and the projection of the second negative pole lug are at least partially overlapped. According to the invention, the cycle life and safety of the battery cell can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell and an electrical device. Background Technology

[0002] Currently, with the rapid development of new energy technologies, battery cells have been widely used in electronic devices, electric vehicles, electric two-wheelers, power tools, and other fields. As the application of battery cells becomes more widespread, higher requirements are being placed on their cycle life. Summary of the Invention

[0003] This application provides a battery cell and an electrical device that can improve the cycle life of the battery cell.

[0004] In a first aspect, this application provides a battery cell, comprising an electrode assembly including a positive electrode and a negative electrode. The positive electrode includes a plurality of first positive tabs and a plurality of second positive tabs, and the negative electrode includes a plurality of first negative tabs and a plurality of second negative tabs. The first positive and first negative tabs are located at one end of the electrode assembly along its length, and the second positive and second negative tabs are located at the other end of the electrode assembly along its length. Along the thickness direction of the electrode assembly, the projections of the first positive tabs and the first negative tabs at least partially overlap, and the projections of the second positive tabs and the second negative tabs at least partially overlap.

[0005] In the above technical solution, by making the positive electrode plate include multiple first positive electrode tabs and multiple second positive electrode tabs, and the negative electrode plate include multiple first negative electrode tabs and multiple second negative electrode tabs, with the first positive electrode tabs and first negative electrode tabs located at one end of the electrode assembly along its length, and the second positive electrode tabs and second negative electrode tabs located at the other end of the electrode assembly along its length, the number of first positive electrode tabs and second positive electrode tabs drawn from the positive electrode plate can be increased, thereby increasing the total current-carrying area of ​​the multiple first positive electrode tabs and multiple second positive electrode tabs. Similarly, the number of first negative electrode tabs and second negative electrode tabs drawn from the negative electrode plate can be increased, thereby increasing the total current-carrying area of ​​the multiple first negative electrode tabs and multiple second negative electrode tabs. This improves the current-carrying capacity of the battery cell, reduces the internal resistance of the battery cell, helps to reduce the temperature rise of the battery cell, reduces the risk of thermal runaway of the battery cell, and improves the cycle life and safety of the battery cell.

[0006] Compared to battery cells where the positive and negative electrode tabs are spaced apart along the width direction of the electrode assembly, this application optimizes the electron transport path within the electrode assembly by ensuring that the projections of the first positive electrode tab and the first negative electrode tab, and the projections of the second positive electrode tab and the second negative electrode tab, at least partially overlap along the thickness direction of the electrode assembly. This reduces the internal resistance of the battery cell, which in turn reduces the temperature rise and the risk of thermal runaway, thus improving the cycle life and safety of the battery cell. Furthermore, the increased upper limit of the tab width along the width direction of the electrode assembly lowers the thickness requirements for the current collectors of the tabs and electrode plates, which is beneficial for increasing the energy density of the battery cell.

[0007] According to some embodiments of this application, the electrode assembly is a wound structure, comprising a first straight region, a first corner region, a second straight region, and a second corner region sequentially connected in its winding direction. The first straight region and the second straight region are arranged opposite to each other in the thickness direction of the electrode assembly, and the first corner region and the second corner region are arranged opposite to each other in the width direction of the electrode assembly. The length direction of the electrode assembly is parallel to the winding axis direction of the electrode assembly. A first positive electrode tab is connected to the first straight region, a first negative electrode tab is connected to the second straight region, a second positive electrode tab is connected to the first straight region, and a second negative electrode tab is connected to the second straight region; or, a first positive electrode tab is connected to the first straight region, a first negative electrode tab is connected to the second straight region, a second positive electrode tab is connected to the second straight region, and a second negative electrode tab is connected to the first straight region.

[0008] In the above technical solution, by connecting each tab to the flat area of ​​the electrode assembly, it is easy to close and connect multiple tabs. Furthermore, the width of the tab can be set to be larger along the width direction of the electrode assembly, which can increase the current-carrying area of ​​the tab, reduce the internal resistance of the cell, reduce the temperature rise of the cell, reduce the risk of thermal runaway of the cell, and improve the cycle life and safety of the cell.

[0009] According to some embodiments of this application, each layer of positive electrode sheet in the first flat region is provided with a first positive electrode tab and a second positive electrode tab, and each layer of negative electrode sheet in the second flat region is provided with a first negative electrode tab and a second negative electrode tab.

[0010] In the above technical solution, by providing a first positive electrode tab and a second positive electrode tab for each layer of positive electrode sheet in the first flat region, and a first negative electrode tab and a second negative electrode tab for each layer of negative electrode sheet in the second flat region, the number of first positive electrode tabs, second positive electrode tabs, first negative electrode tabs, and second negative electrode tabs can be increased, and the total current-carrying area of ​​the first positive electrode tab and second positive electrode tab and the first negative electrode tab and second negative electrode tab can be increased. This reduces the internal resistance of the battery cell, which is beneficial to reducing the temperature rise of the battery cell, reducing the risk of thermal runaway, and improving the cycle life and safety of the battery cell. Compared with a battery cell where the positive and negative electrode tabs are spaced apart along the width direction of the electrode assembly, and each layer of positive electrode sheet has a positive electrode tab and each layer of negative electrode sheet has a negative electrode tab, the present application has fewer positive and negative electrode tabs, which facilitates the fabrication of the positive and negative electrode sheets.

[0011] According to some embodiments of this application, each layer of positive electrode sheet in the first flat region is provided with a first positive electrode tab, each layer of negative electrode sheet in the first flat region is provided with a second negative electrode tab, each layer of negative electrode sheet in the second flat region is provided with a first negative electrode tab, and each layer of positive electrode sheet in the second flat region is provided with a second positive electrode tab.

[0012] In the above technical solution, by providing a first positive electrode tab for each layer of positive electrode sheet in the first flat region, a second negative electrode tab for each layer of negative electrode sheet in the first flat region, a first negative electrode tab for each layer of negative electrode sheet in the second flat region, and a second positive electrode tab for each layer of positive electrode sheet in the second flat region, the number of first positive electrode tabs, second positive electrode tabs, first negative electrode tabs, and second negative electrode tabs can be increased, the total current-carrying area of ​​the first positive electrode tabs and second positive electrode tabs can be increased, and the total current-carrying area of ​​the first negative electrode tabs and second negative electrode tabs can be increased. This can reduce the internal resistance of the battery cell, which is beneficial to reducing the temperature rise of the battery cell, reducing the risk of thermal runaway of the battery cell, and improving the cycle life and safety of the battery cell. Compared to cells where positive and negative electrodes are spaced apart along the width of the electrode assembly, and each layer of positive electrode sheet has a positive electrode tab and each layer of negative electrode sheet has a negative electrode tab, the present application has fewer positive and negative electrodes tabs, which facilitates the fabrication of positive and negative electrodes.

[0013] According to some embodiments of this application, the battery cell further includes a packaging bag, which includes a main body and a packaging portion. The main body is used to accommodate the electrode assembly. The battery cell also includes a first electrical connector, a second electrical connector, and a first insulating member. The first electrical connector is electrically connected to a plurality of first positive electrode tabs, and the second electrical connector is electrically connected to a plurality of first negative electrode tabs. The first and second electrical connectors extend out of the packaging bag through the packaging portion. The first insulating member seals the gap between the first electrical connector and the packaging portion, and also seals the gap between the second electrical connector and the packaging portion. A portion of the first insulating member is located between the first and second electrical connectors to isolate them.

[0014] In the above technical solution, compared with the battery cell where the positive and negative electrodes are spaced apart along the width direction of the electrode assembly, in this application, the upper limit of the width of the electrodes along the width direction of the electrode assembly is increased, and the upper limit of the width of the first and second electrical connectors is also increased. This can reduce the thickness requirements of the first and second electrical connectors, making it easier to bend them when connecting them to external components. This can improve the connection efficiency between the first and second electrical connectors and external components, reduce the risk of incomplete welding when the first and second electrical connectors are welded to external components, and help improve the safety and reliability of electrical equipment.

[0015] By sealing the gap between the first electrical connector and the package portion with the first insulating member, and sealing the gap between the second electrical connector and the package portion, a portion of the first insulating member is located between the first electrical connector and the second electrical connector to isolate the first electrical connector and the second electrical connector. This facilitates the sealing between the first electrical connector, the second electrical connector and the package portion, and ensures that the first electrical connector and the second electrical connector are spaced apart along the thickness direction of the electrode assembly, reducing the risk of short circuit between the first electrical connector and the second electrical connector and improving the safety of the battery cell.

[0016] According to some embodiments of this application, the battery cell further includes a third electrical connector, a fourth electrical connector, and a second insulating member. The third electrical connector is electrically connected to a plurality of second positive electrodes, and the fourth electrical connector is electrically connected to a plurality of second negative electrodes. The third and fourth electrical connectors extend out of the packaging bag through the encapsulation portion. The second insulating member seals the gap between the third electrical connector and the encapsulation portion and seals the gap between the fourth electrical connector and the encapsulation portion. A portion of the second insulating member is located between the third and fourth electrical connectors to isolate the third and fourth electrical connectors.

[0017] In the above technical solution, compared with the battery cell where the positive and negative electrodes are spaced apart along the width direction of the electrode assembly, the upper limit of the electrode width along the width direction of the electrode assembly is increased in this application, and the upper limit of the width of the third and fourth electrical connectors is also increased. This can reduce the thickness requirements of the third and fourth electrical connectors, making it easier to bend them when connecting them to external components. This can improve the connection efficiency between the third and fourth electrical connectors and external components, reduce the risk of poor welding when the third and fourth electrical connectors are welded to external components, and help improve the safety and reliability of electrical equipment.

[0018] By sealing the gap between the third electrical connector and the package portion and sealing the gap between the fourth electrical connector and the package portion with the second insulating member partially located between the third and fourth electrical connectors to isolate the third and fourth electrical connectors, it is possible to facilitate the sealing between the third and fourth electrical connectors and the package portion. Furthermore, it is possible to maintain a gap between the third and fourth electrical connectors along the thickness direction of the electrode assembly, thereby reducing the risk of short circuits between the third and fourth electrical connectors and improving the safety of the battery cell.

[0019] According to some embodiments of this application, along the thickness direction of the electrode assembly, the first insulating member includes a first portion, a second portion, and a third portion. The first portion is located between the encapsulation portion and the first electrical connector, the second portion is located between the encapsulation portion and the second electrical connector, and the third portion is located between the first electrical connector and the second electrical connector. Along the length direction of the electrode assembly, the first electrical connector has a first edge near the first positive electrode tab, the second electrical connector has a second edge near the first negative electrode tab, and the third portion extends to both the first and second edges.

[0020] In the above technical solution, by extending the third part to the first edge and the second edge, the third part can serve as an insulator for the end of the first electrical connector and the second electrical connector near the electrode assembly, further reducing the risk of short circuit between the first electrical connector and the second electrical connector and improving the safety of the battery cell.

[0021] According to some embodiments of this application, the thickness of the first part is H1, where 0.1mm ≤ H1 ≤ 0.25mm.

[0022] In the above technical solution, when H1 is equal to or equal to 0.1mm, the insulation and sealing effect between the first part and the encapsulation part and the first electrical connector is better, reducing the risk of short circuit between the first electrical connector and the encapsulation part, and reducing the risk of cell leakage or external moisture infiltration, which is beneficial to improving the safety of the cell. When H1 is less than or equal to 0.25mm, it is easier for the first part to melt and connect with the encapsulation part and the first electrical connector, and it is easier to reduce the space occupied by the first part, which is beneficial to improving the energy density of the cell. Therefore, when 0.1mm≤H1≤0.25mm, it can reduce the risk of short circuit between the first electrical connector and the encapsulation part, reduce the risk of cell leakage or external moisture infiltration, which is beneficial to improving the safety of the cell, and it can also facilitate the melting of the first part and its connection with the encapsulation part and the first electrical connector, which is beneficial to improving the energy density of the cell.

[0023] According to some embodiments of this application, the thickness of the second part is H2, where 0.1mm ≤ H2 ≤ 0.25mm.

[0024] In the above technical solution, when H2 is equal to or equal to 0.1mm, the insulation and sealing effect between the second part and the encapsulation part and the second electrical connector is better, reducing the risk of short circuit between the second electrical connector and the encapsulation part, and reducing the risk of cell leakage or external moisture infiltration, which is beneficial to improving the safety of the cell. When H2 is less than or equal to 0.25mm, it is easier for the second part to melt and connect with the encapsulation part and the second electrical connector, and it is easier to reduce the space occupied by the second part, which is beneficial to improving the energy density of the cell. Therefore, when 0.1mm≤H2≤0.25mm, it can not only reduce the risk of short circuit between the second electrical connector and the encapsulation part, reduce the risk of cell leakage or external moisture infiltration, which is beneficial to improving the safety of the cell, but also facilitate the melting of the second part and its connection with the encapsulation part and the second electrical connector, and is beneficial to improving the energy density of the cell.

[0025] According to some embodiments of this application, the thickness of the third part is H3, where 0.1mm ≤ H3 ≤ 0.25mm.

[0026] In the above technical solution, when H3 is equal to or equal to 0.1mm, the insulation and sealing effect of the third part on the first and second electrical connectors is better, reducing the risk of short circuit between the first and second electrical connectors and reducing the risk of cell leakage or external moisture infiltration, which is beneficial to improving the safety of the cell. When H3 is less than or equal to 0.25mm, the third part can be easily melted and connected to the first and second electrical connectors, and the space occupied by the third part can be reduced, which is beneficial to improving the energy density of the cell. Therefore, when 0.1mm≤H3≤0.25mm, the risk of short circuit between the first and second electrical connectors and the risk of cell leakage or external moisture infiltration can be reduced, which is beneficial to improving the safety of the cell. At the same time, the third part can be easily melted and connected to the first and second electrical connectors, which is beneficial to improving the energy density of the cell.

[0027] According to some embodiments of this application, the cross-sectional area of ​​the first electrical connector perpendicular to the length direction of the electrode assembly is S1, and the cross-sectional area of ​​the second electrical connector perpendicular to the length direction of the electrode assembly is S2, where 1≤S1 / S2≤1.6.

[0028] In the above technical solution, due to the different materials of the first positive electrode tab and the first negative electrode tab, under the condition of the same current-carrying area, the heat generated by the first positive electrode tab during the charging and discharging process of the battery cell will be greater than that of the first negative electrode tab. When S1 / S2 is greater than or equal to 1, the current-carrying area of ​​the first positive electrode tab can be larger than that of the first negative electrode tab, improving the current-carrying capacity of the first positive electrode tab, reducing the heat generated by the first positive electrode tab, and ensuring that the temperature rise of the first positive electrode tab is not too high compared to that of the first negative electrode tab, thereby reducing the temperature rise difference between the first positive electrode tab and the first negative electrode tab; when S1 / S2 is less than or equal to 1.6, the current-carrying area of ​​the first positive electrode tab is not too large, and the temperature rise of the first positive electrode tab is not too low compared to that of the first negative electrode tab, thus reducing the temperature rise difference between the first positive electrode tab and the first negative electrode tab. Reducing the temperature rise difference between the first positive and first negative electrode tabs reduces the risk of thermal shrinkage of the separator due to excessive local temperature rise in the battery cell, thereby reducing the risk of thermal runaway caused by short circuit between the positive and negative electrode plates and improving the safety of the battery cell. Therefore, when 1≤S1 / S2≤1.6, the temperature rise difference between the first positive and first negative electrode tabs can be reduced, reducing the risk of thermal shrinkage of the separator due to excessive local temperature rise in the battery cell, thereby reducing the risk of thermal runaway caused by short circuit between the positive and negative electrode plates and improving the safety of the battery cell.

[0029] According to some embodiments of this application, the width of the battery cell is W0, and the width of the first electrical connector is W1, where 30mm≤W1≤W0-20mm.

[0030] In the above technical solution, when W1 is greater than or equal to 30mm, the width of the first electrical connector is not too small, and the current-passing area of ​​the first electrical connector is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When W1 is less than or equal to W0-20mm, it facilitates the sealing between the first electrical connector and the packaging part, reduces the risk of battery cell leakage or external moisture infiltration, and helps to improve the safety of the battery cell. Therefore, when 30mm≤W1≤W0-20mm, it can reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, and also reduces the risk of battery cell leakage or external moisture infiltration, which helps to improve the safety of the battery cell.

[0031] According to some embodiments of this application, the width of the second electrical connector is W2, where 30mm ≤ W2 ≤ W0 - 20mm.

[0032] In the above technical solution, when W2 is greater than or equal to 30mm, the width of the second electrical connector is not too small, and the current-passing area of ​​the second electrical connector is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When W2 is less than or equal to W0-20mm, it facilitates the sealing between the second electrical connector and the packaging part, reduces the risk of battery cell leakage or external moisture infiltration, and helps to improve the safety of the battery cell. Therefore, when 30mm≤W2≤W0-20mm, it can reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, and also reduces the risk of battery cell leakage or external moisture infiltration, which helps to improve the safety of the battery cell.

[0033] According to some embodiments of this application, the thickness of the first electrical connector is H4, where 0.1mm ≤ H4 ≤ 0.8mm.

[0034] In the above technical solution, when H4 is greater than or equal to 0.1mm, the thickness of the first electrical connector is not too small, and the current-carrying area of ​​the first electrical connector is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When H4 is less than or equal to 0.8mm, it facilitates the sealing between the first electrical connector and the packaging part, reduces the risk of battery cell leakage or external moisture infiltration, and helps to improve the safety of the battery cell. Therefore, when 0.1mm≤H4≤0.8mm, it can reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, and also reduces the risk of battery cell leakage or external moisture infiltration, which helps to improve the safety of the battery cell.

[0035] According to some embodiments of this application, the thickness of the second electrical connector is H5, where 0.1mm ≤ H5 ≤ 0.7mm.

[0036] In the above technical solution, when H5 is greater than or equal to 0.1mm, the thickness of the second electrical connector is not too small, and the current-passing area of ​​the second electrical connector is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When H5 is less than or equal to 0.7mm, it facilitates the sealing between the second electrical connector and the packaging part, reduces the risk of battery cell leakage or external moisture infiltration, and helps to improve the safety of the battery cell. Therefore, when 0.1mm≤H5≤0.7mm, it can reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, and also reduces the risk of battery cell leakage or external moisture infiltration, which helps to improve the safety of the battery cell.

[0037] According to some embodiments of this application, the width of the battery cell is W0, where 100mm ≤ W0 ≤ 200mm.

[0038] In the above technical solution, when W0 is greater than or equal to 100mm, the width of the battery cell is not too small, which is beneficial to improving the energy density of the battery cell; when W0 is less than or equal to 200mm, the width of the battery cell is not too large, which allows the battery cell to be used in more types of electrical equipment and improves the applicability of the battery cell; therefore, when 100mm≤W0≤200mm, it is beneficial to both improve the energy density of the battery cell and make the battery cell suitable for more types of electrical equipment, thus improving the applicability of the battery cell.

[0039] According to some embodiments of this application, the width of the first electrical connector is W1, the width of the first positive electrode tab is C1, and W1-5mm≤C1≤W1-2mm.

[0040] In the above technical solution, when C1 is greater than or equal to W1-5mm, the width of the first positive electrode tab is not too small, and the current-carrying area of ​​the first positive electrode tab is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When C1 is less than or equal to W1-2mm, it is easier to bend and fold multiple first positive electrode tabs and connect them to the first electrical connector, which helps to improve the manufacturing efficiency of the battery cell. Therefore, when W1-5mm≤C1≤W1-2mm, it can not only reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, but also facilitate the bending and folding of multiple first positive electrode tabs and their connection to the first electrical connector, which helps to improve the manufacturing efficiency of the battery cell.

[0041] According to some embodiments of this application, the width of the second electrical connector is W2, the width of the first negative electrode tab is C2, and W2-5mm≤C2≤W2-2mm.

[0042] In the above technical solution, when C2 is greater than or equal to W2-5mm, the width of the first negative electrode tab is not too small, and the current-carrying area of ​​the first negative electrode tab is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When C2 is less than or equal to W2-2mm, it is easier to bend and fold multiple first negative electrode tabs and connect them to the second electrical connector, which helps to improve the manufacturing efficiency of the battery cell. Therefore, when W2-5mm≤C2≤W2-2mm, it can not only reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, but also facilitate the bending and folding of multiple first negative electrode tabs and their connection to the second electrical connector, which helps to improve the manufacturing efficiency of the battery cell.

[0043] According to some embodiments of this application, the width of the third electrical connector is W3, the width of the second positive electrode tab is C3, and W3-5mm≤C3≤W3-2mm.

[0044] In the above technical solution, when C3 is greater than or equal to W3-5mm, the width of the second positive electrode tab is not too small, and the current-carrying area of ​​the second positive electrode tab is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When C3 is less than or equal to W3-2mm, it is easier to bend and fold multiple second positive electrode tabs and connect them to the third electrical connector, which helps to improve the manufacturing efficiency of the battery cell. Therefore, when W3-5mm≤C3≤W3-2mm, it can not only reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, but also facilitate the bending and folding of multiple second positive electrode tabs and their connection to the third electrical connector, which helps to improve the manufacturing efficiency of the battery cell.

[0045] According to some embodiments of this application, the width of the fourth electrical connector is W4, the width of the second negative electrode tab is C4, and W4-5mm≤C4≤W4-2mm.

[0046] In the above technical solution, when C4 is greater than or equal to W4-5mm, the width of the second negative electrode tab is not too small, and the current-carrying area of ​​the second negative electrode tab is not too small. This reduces the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell. When C4 is less than or equal to W4-2mm, it is easier to bend and fold multiple second negative electrode tabs and connect them to the fourth electrical connector, which helps to improve the manufacturing efficiency of the battery cell. Therefore, when W4-5mm≤C4≤W4-2mm, it can not only reduce the internal resistance of the battery cell, which helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell, but also facilitate the bending and folding of multiple second negative electrode tabs and their connection to the fourth electrical connector, which helps to improve the manufacturing efficiency of the battery cell.

[0047] According to some embodiments of this application, along the width direction of the electrode assembly, the width of the first electrical connector is W1, the width of the second electrical connector is W2, the width of the first insulating member is W5, W5≥W1, and W5≥W2.

[0048] In the above technical solution, by making W5≥W1 and W5≥W2, the first insulating member can cover the first electrical connector and the second electrical connector in the width direction of the electrode assembly. This makes the insulation and sealing effect between the first electrical connector and the encapsulation part, and between the second electrical connector and the encapsulation part, better. This can reduce the risk of short circuit between the first electrical connector and the encapsulation part, and between the second electrical connector and the encapsulation part, and can also reduce the risk of cell leakage or external moisture infiltration, which is beneficial to improving the safety of the cell.

[0049] According to some embodiments of this application, 4mm≤W5-W1≤10mm, 4mm≤W5-W2≤10mm.

[0050] In the above technical solution, when W5-W1 is greater than or equal to 4mm and W5-W2 is greater than or equal to 4mm, the first insulating member can cover the first electrical connector and the second electrical connector in the width direction of the electrode assembly. This improves the insulation and sealing effect between the first electrical connector and the encapsulation part, and between the second electrical connector and the encapsulation part, reducing the risk of short circuits between the first electrical connector and the encapsulation part, and between the second electrical connector and the encapsulation part. It also reduces the risk of cell leakage or external moisture infiltration, thus improving the safety of the cell. When W5-W1 is less than or equal to 10mm and W5-W2 is less than or equal to 10mm, the space occupied by the first insulating member is not too large, which helps to improve the energy density of the cell. Therefore, when 4mm≤W5-W1≤10mm and 4mm≤W5-W2≤10mm, both the safety and energy density of the cell can be improved.

[0051] According to some embodiments of this application, the sum of the cross-sectional area of ​​the first electrical connector perpendicular to the length direction of the electrode assembly and the cross-sectional area of ​​the third electrical connector perpendicular to the length direction of the electrode assembly is S3 (unit: mm). 2 ), 20%≤5A / mm 2 ×S3 / (E×C)≤50%. Where E is the rated capacity of the cell (in Ah), and C is the maximum discharge rate of the cell (in L / h).

[0052] In the above technical solution, the materials of the first and third electrical connectors are the same as the material of the positive electrode tab, namely aluminum, and the current carrying capacity of aluminum is 5A / mm². 2 5A / mm 2 ×S3 represents the total current-conducting capacity of the first and third electrical connectors, and E×C represents the discharge current of the battery cell. When 5A / mm 2 ×S3 / (E×C) is greater than or equal to 20%, ensuring that the total current-carrying capacity of the first and third electrical connectors is not too small, reducing the risk of overheating of the first and third electrical connectors, reducing the risk of thermal runaway of the battery cell, and improving the cycle life and safety of the battery cell; when 5A / mm 2 ×S3 / (E×C) is less than or equal to 50%, ensuring that the total current-carrying capacity of the first and third electrical connectors is not too large, and that the cross-sectional area of ​​the first and / or third electrical connectors is not too large, thus reducing the space occupied by the first and / or third electrical connectors and improving the energy density of the battery cell; therefore, when 20%≤5A / mm 2 ×S3 / (E×C)≤50% can reduce the risk of thermal runaway in the battery cell, improve the cycle life and safety of the battery cell, and also help to improve the energy density of the battery cell.

[0053] According to some embodiments of this application, the sum of the cross-sectional area of ​​the second electrical connector perpendicular to the length direction of the electrode assembly and the cross-sectional area of ​​the fourth electrical connector perpendicular to the length direction of the electrode assembly is S4 (unit: mm). 2 ), 20%≤8 A / mm 2 ×S4 / (E×C)≤50%. Where E is the rated capacity of the cell and C is the maximum discharge rate of the cell.

[0054] In the above technical solution, the materials of the second and fourth electrical connectors are the same as those of the negative electrode tab, namely copper, and copper has a current carrying capacity of 8 A / mm². 2 8A / mm 2 ×S4 represents the total current-conducting capacity of the second and fourth electrical connectors, and E×C represents the discharge current of the battery cell. When 8 A / mm 2×S4 / (E×C) is greater than or equal to 20%, ensuring that the total current conductivity of the second and fourth electrical connectors is not too small, reducing the risk of overheating of the second and fourth electrical connectors, reducing the risk of thermal runaway of the battery cell, and improving the cycle life and safety of the battery cell; when 8 A / mm 2 ×S4 / (E×C) is less than or equal to 50%, ensuring that the total current-carrying capacity of the second and fourth electrical connectors is not too large, and that the cross-sectional area of ​​the second and / or fourth electrical connectors is not too large, thus reducing the space occupied by the second and / or fourth electrical connectors and improving the energy density of the battery cell; therefore, when 20%≤8 A / mm 2 ×S4 / (E×C)≤50% can reduce the risk of thermal runaway in the battery cell, improve the cycle life and safety of the battery cell, and also help to improve the energy density of the battery cell.

[0055] According to some embodiments of this application, the sum of the cross-sectional areas of the plurality of first positive electrode tabs perpendicular to the length direction of the electrode assembly and the cross-sectional areas of the plurality of second positive electrode tabs perpendicular to the length direction of the electrode assembly is S5 (unit: mm). 2 ), 20%≤5 A / mm 2 ×S5 / (E×C)≤50%. Where E is the rated capacity of the cell and C is the maximum discharge rate of the cell.

[0056] In the above technical solution, the first positive electrode tab and the second positive electrode tab are made of aluminum, and aluminum has a current carrying capacity of 5A / mm². 2 5A / mm 2 ×S5 represents the total current conductivity of the multiple first positive electrode tabs and multiple second positive electrode tabs, and E×C represents the discharge current of the battery cell. When 5A / mm 2 ×S5 / (E×C) is greater than or equal to 20%, ensuring that the total current conductivity of multiple first positive electrodes and multiple second positive electrodes is not too small, reducing the risk of overheating of the first and second positive electrodes, reducing the risk of thermal runaway of the battery cell, and improving the cycle life and safety of the battery cell; when 5A / mm 2 ×S5 / (E×C) is less than or equal to 50%, ensuring that the total current-carrying capacity of the multiple first positive electrodes and multiple second positive electrodes is not too large, and that the cross-sectional area of ​​the first positive electrodes and / or second positive electrodes is not too large, thus reducing the space occupied by the first positive electrodes and / or second positive electrodes, which is beneficial for improving the energy density of the battery cell; therefore, when 20%≤5A / mm 2 ×S5 / (E×C)≤50% can reduce the risk of thermal runaway in the battery cell, improve the cycle life and safety of the battery cell, and also help to improve the energy density of the battery cell.

[0057] According to some embodiments of this application, the sum of the cross-sectional areas of the plurality of first negative electrode tabs perpendicular to the length direction of the electrode assembly and the cross-sectional areas of the plurality of second negative electrode tabs perpendicular to the length direction of the electrode assembly is S6 (unit: mm). 2 ), 20%≤8 A / mm 2 ×S6 / (E×C)≤50%. Where E is the rated capacity of the cell and C is the maximum discharge rate of the cell.

[0058] In the above technical solution, the first negative electrode tab and the second negative electrode tab are made of copper, and the current carrying capacity of copper is 8A / mm². 2 8A / mm 2 ×S6 represents the total current conductivity of multiple first negative electrode tabs and multiple second negative electrode tabs, and E×C represents the discharge current of the battery cell. (When 8A / mm) 2 ×S6 / (E×C) is greater than or equal to 20%, ensuring that the total current conductivity of multiple first negative electrode tabs and multiple second negative electrode tabs is not too small, reducing the risk of overheating of the first and second negative electrode tabs, reducing the risk of thermal runaway of the battery cell, and improving the cycle life and safety of the battery cell; when 8 A / mm 2 ×S6 / (E×C) is less than or equal to 50%, ensuring that the total current-carrying capacity of multiple first negative electrode tabs and multiple second negative electrode tabs is not too large, and the cross-sectional area of ​​the first negative electrode tab and / or the second negative electrode tab is not too large, thus reducing the space occupied by the first negative electrode tab and / or the second negative electrode tab, which is beneficial to improving the energy density of the cell; therefore, when 20%≤8 A / mm 2 ×S6 / (E×C)≤50% can reduce the risk of thermal runaway in the battery cell, improve the cycle life and safety of the battery cell, and also help to improve the energy density of the battery cell.

[0059] Secondly, this application provides an electrical device including a battery cell as described above, the battery cell being used to provide electrical energy. Attached Figure Description

[0060] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings.

[0061] Figure 1 A three-dimensional structural schematic diagram of a battery cell provided in some embodiments of this application; Figure 2 A cross-sectional view of the electrode assembly of a battery cell provided in some embodiments of this application; Figure 3A cross-sectional view of the electrode assembly of a battery cell provided in some embodiments of this application; Figure 4 A schematic structural diagram from one perspective of a portion of the battery cell structure provided in some embodiments of this application; Figure 5 A schematic diagram of a portion of the battery cell structure provided in some embodiments of this application, from another perspective; Figure 6 A cross-sectional view of the electrode assembly of a battery cell provided in some other embodiments of this application; Figure 7 A cross-sectional view of the electrode assembly of a battery cell provided in other embodiments of this application; Figure 8 A schematic diagram of the structure of a battery cell from one perspective, provided for other embodiments of this application; Figure 9 This is a schematic diagram of the battery cell from another perspective, provided for some other embodiments of this application. Figure 10 A schematic diagram from one perspective of a portion of the structure of a battery cell provided in some embodiments of this application; Figure 11 This is a schematic diagram of a portion of the battery cell structure provided in some embodiments of this application from another perspective.

[0062] Icons: 10-Battery cell; 100-Electrode assembly; 101-First straight region; 102-First corner region; 103-Second straight region; 104-Second corner region; 110-Positive electrode sheet; 111-First positive electrode tab; 112-Second positive electrode tab; 120-Negative electrode sheet; 121-First negative electrode tab; 122-Second negative electrode tab; 130-Separator membrane; 200-Packaging bag; 210-Main body; 220- Encapsulation section; 310 - First electrical connector; 311 - First edge; 320 - Second electrical connector; 321 - Second edge; 330 - Third electrical connector; 340 - Fourth electrical connector; 410 - First insulating member; 411 - First part; 412 - Second part; 413 - Third part; 420 - Second insulating member; X - Length direction of electrode assembly; Y - Thickness direction of electrode assembly; Z - Width direction of electrode assembly. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0064] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having" and any variations thereof in the specification, claims and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0065] The terms "first," "second," etc., in the specification, claims, or the accompanying drawings of this application are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0066] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0067] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0068] With the development of the new energy industry, batteries are gradually moving towards higher energy density and higher power density, and the requirements for battery cycle life are becoming increasingly stringent. In a battery cell, the positive and negative electrodes are typically led out through positive and negative tabs to achieve electrical connection between the cell and the load. Currently, the positive and negative tabs are only led out on one side of the cell, resulting in a limited number of tabs and a smaller total current-carrying area. This affects the cell's current-carrying capacity and, consequently, its cycle life.

[0069] To improve the cycle life of a battery cell, this application provides a battery cell including an electrode assembly. The electrode assembly includes a positive electrode and a negative electrode. The positive electrode includes a plurality of first positive tabs and a plurality of second positive tabs, and the negative electrode includes a plurality of first negative tabs and a plurality of second negative tabs. The first positive tabs and first negative tabs are located at one end of the electrode assembly along its length, and the second positive tabs and second negative tabs are located at the other end of the electrode assembly along its length. Along the thickness direction of the electrode assembly, the projections of the first positive tabs and the first negative tabs at least partially overlap, and the projections of the second positive tabs and the second negative tabs at least partially overlap.

[0070] In this type of battery cell structure, by having the positive electrode plate include multiple first positive tabs and multiple second positive tabs, and the negative electrode plate include multiple first negative tabs and multiple second negative tabs, with the first positive and first negative tabs located at one end of the electrode assembly along its length and the second positive and second negative tabs located at the other end of the electrode assembly along its length, the number of first positive and second positive tabs leading out from the positive electrode plate can be increased, thereby increasing the total current-carrying area of ​​the multiple first positive and multiple second positive tabs. Similarly, the number of first negative and second negative tabs leading out from the negative electrode plate can be increased, thereby increasing the total current-carrying area of ​​the multiple first negative and multiple second negative tabs. This improves the current-carrying capacity of the battery cell, reduces the internal resistance of the battery cell, helps to reduce the temperature rise of the battery cell, reduces the risk of thermal runaway of the battery cell, and improves the cycle life and safety of the battery cell.

[0071] Compared to battery cells where the positive and negative electrode tabs are spaced apart along the width direction of the electrode assembly, this application optimizes the electron transport path within the electrode assembly by ensuring that the projections of the first positive electrode tab and the first negative electrode tab, and the projections of the second positive electrode tab and the second negative electrode tab, at least partially overlap along the thickness direction of the electrode assembly. This reduces the internal resistance of the battery cell, which in turn reduces the temperature rise and the risk of thermal runaway, thus improving the cycle life and safety of the battery cell. Furthermore, the increased upper limit of the tab width along the width direction of the electrode assembly lowers the thickness requirements for the current collectors of the tabs and electrode plates, which is beneficial for increasing the energy density of the battery cell.

[0072] The battery cell provided in this application embodiment can be a secondary battery, such as a lithium-ion battery, sodium-ion battery, or magnesium-ion battery, etc., and this application embodiment is not limited in this respect. The battery cell can be cylindrical, flat, cuboid, or other shapes, etc., and this application embodiment is not limited in this respect either.

[0073] This application provides an electrical device that uses battery cells as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc.

[0074] See Figure 1 and Figure 2 , Figure 1 A three-dimensional structural schematic diagram of a battery cell provided in some embodiments of this application; Figure 2 This is a cross-sectional view of the electrode assembly of a battery cell provided in some embodiments of this application.

[0075] This application provides a battery cell 10, which includes an electrode assembly 100, a packaging bag 200, and an electrolyte. The electrode assembly 100 and the electrolyte are contained within the packaging bag 200. The electrode assembly 100 also includes a positive electrode 110, a negative electrode 120, and a separator 130. The battery cell 10 mainly operates by the movement of metal ions between the positive electrode 110 and the negative electrode 120. The positive electrode 110 includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the portion of the positive current collector without the positive active material layer serves as a positive electrode tab, through which electrical energy is input or output to the positive electrode 110. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary materials (such as lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, etc.), or lithium manganese oxide, etc. The negative electrode 120 includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the portion of the negative current collector not coated with the negative active material layer serves as a negative electrode tab, through which electrical energy is input or output from the negative electrode 120. The material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc. The separator 130 can be made of polypropylene (PP) or polyethylene (PE), etc. The electrolyte can include organic solvents, lithium salts, etc.

[0076] In some embodiments, the packaging bag 200 may be made of a flexible material, such as aluminum-plastic film, steel-plastic film, etc.

[0077] See 2 to Figure 5 , Figure 3 A cross-sectional view of the electrode assembly of a battery cell provided in some embodiments of this application; Figure 4 A schematic structural diagram from one perspective of a portion of the battery cell structure provided in some embodiments of this application; Figure 5 This is a schematic diagram of a portion of the battery cell structure provided in some embodiments of this application, from another perspective.

[0078] In some embodiments, the positive electrode 110 includes a plurality of first positive electrode tabs 111 and a plurality of second positive electrode tabs 112, and the negative electrode 120 includes a plurality of first negative electrode tabs 121 and a plurality of second negative electrode tabs 122. The first positive electrode tabs 111 and the first negative electrode tabs 121 are located at one end of the electrode assembly 100 along its length direction X, and the second positive electrode tabs 112 and the second negative electrode tabs 122 are located at the other end of the electrode assembly 100 along its length direction X.

[0079] By making the positive electrode 110 include a plurality of first positive electrode tabs 111 and a plurality of second positive electrode tabs 112, and the negative electrode 120 include a plurality of first negative electrode tabs 121 and a plurality of second negative electrode tabs 122, with the first positive electrode tabs 111 and 121 located at one end of the electrode assembly 100 along its length direction X, and the second positive electrode tabs 112 and 122 located at the other end of the electrode assembly 100 along its length direction X, it is possible to make the first positive electrode tabs 111 and 122 led out from the positive electrode 110... The large number of tabs 112 increases the total current-carrying area of ​​the multiple first positive tabs 111 and multiple second positive tabs 112, resulting in a large number of first negative tabs 121 and second negative tabs 122 leading out from the negative electrode plate 120. This further increases the total current-carrying area of ​​the multiple first negative tabs 121 and multiple second negative tabs 122, thereby improving the current-carrying capacity of the cell 10, reducing the internal resistance of the cell 10, which is beneficial to reducing the temperature rise of the cell 10, reducing the risk of thermal runaway of the cell 10, and improving the cycle life and safety of the cell 10.

[0080] In some embodiments, along the thickness direction Y of the electrode assembly, the projection of the first positive electrode tab 111 at least partially overlaps with the projection of the first negative electrode tab 121, and the projection of the second positive electrode tab 112 at least partially overlaps with the projection of the second negative electrode tab 122.

[0081] Compared to a battery cell 10 where the positive and negative electrode tabs are spaced apart along the width direction Z of the electrode assembly, this application optimizes the electron transport path within the electrode assembly 100 by ensuring that the projections of the first positive electrode tab 111 and the first negative electrode tab 121 at least partially overlap, and the projections of the second positive electrode tab 112 and the second negative electrode tab 122 at least partially overlap, along the thickness direction Y of the electrode assembly. This reduces the internal resistance of the battery cell 10, which in turn reduces the temperature rise of the battery cell 10, decreases the risk of thermal runaway, and improves the cycle life and safety of the battery cell 10. Furthermore, the increased upper limit of the tab width along the width direction Z of the electrode assembly reduces the thickness requirements for the current collectors of the tabs and electrode sheets, thus improving the energy density of the battery cell 10.

[0082] The length direction X, thickness direction Y, and width direction Z of the electrode assembly are perpendicular to each other.

[0083] See Figure 2 and Figure 3In some embodiments, the electrode assembly 100 is a wound structure. The electrode assembly 100 includes a first straight region 101, a first corner region 102, a second straight region 103, and a second corner region 104 connected sequentially in its winding direction. The first straight region 101 and the second straight region 103 are arranged opposite to each other in the thickness direction Y of the electrode assembly, and the first corner region 102 and the second corner region 104 are arranged opposite to each other in the width direction Z of the electrode assembly. The length direction X of the electrode assembly is parallel to the winding axis direction of the electrode assembly 100. A first positive electrode tab 111 is connected to the first straight region 101, a first negative electrode tab 121 is connected to the second straight region 103, a second positive electrode tab 112 is connected to the first straight region 101, and a second negative electrode tab 122 is connected to the second straight region 103.

[0084] By connecting the first positive electrode tab 111 to the first flat region 101, the first negative electrode tab 121 to the second flat region 103, the second positive electrode tab 112 to the first flat region 101, and the second negative electrode tab 122 to the second flat region 103, it is possible to facilitate the retraction and connection of multiple first positive electrode tabs 111, multiple first negative electrode tabs 121, multiple second positive electrode tabs 112, and multiple second negative electrode tabs 122. Furthermore, along the width direction Z of the electrode assembly, the width of each tab can be set to be relatively large, which can increase the current-carrying area of ​​the tabs, reduce the internal resistance of the cell 10, help reduce the temperature rise of the cell 10, reduce the risk of thermal runaway of the cell 10, and improve the cycle life and safety of the cell 10.

[0085] See Figures 6 to 9 , Figure 6 A cross-sectional view of the electrode assembly of a battery cell provided in some other embodiments of this application; Figure 7 A cross-sectional view of the electrode assembly of a battery cell provided in other embodiments of this application; Figure 8 A schematic diagram of the structure of a battery cell from one perspective, provided for other embodiments of this application; Figure 9 This is a structural schematic diagram of a battery cell from another perspective, provided for some other embodiments of this application.

[0086] In other embodiments, the first positive electrode tab 111 is connected to the first flat region 101, the first negative electrode tab 121 is connected to the second flat region 103, the second positive electrode tab 112 is connected to the second flat region 103, and the second negative electrode tab 122 is connected to the first flat region 101.

[0087] By connecting the first positive electrode tab 111 to the first flat region 101, the first negative electrode tab 121 to the second flat region 103, the second positive electrode tab 112 to the second flat region 103, and the second negative electrode tab 122 to the first flat region 101, multiple first positive electrode tabs 111, multiple first negative electrode tabs 121, multiple second positive electrode tabs 112, and multiple second negative electrode tabs 122 can be respectively gathered and connected. Furthermore, along the width direction Z of the electrode assembly, the width of each tab can be set to be relatively large, which can increase the current-carrying area of ​​the tabs, reduce the internal resistance of the cell 10, help reduce the temperature rise of the cell 10, reduce the risk of thermal runaway of the cell 10, and improve the cycle life and safety of the cell 10.

[0088] See Figure 2 and Figure 3 In some embodiments, each layer of positive electrode 110 in the first flat region 101 is provided with a first positive electrode tab 111 and a second positive electrode tab 112, and each layer of negative electrode 120 in the second flat region 103 is provided with a first negative electrode tab 121 and a second negative electrode tab 122.

[0089] By providing a first positive electrode tab 111 and a second positive electrode tab 112 for each layer of positive electrode sheet 110 in the first flat region 101, and a first negative electrode tab 121 and a second negative electrode tab 122 for each layer of negative electrode sheet 120 in the second flat region 103, the number of first positive electrode tabs 111, second positive electrode tabs 112, first negative electrode tabs 121, and second negative electrode tabs 122 can be increased, the total overcurrent area of ​​first positive electrode tabs 111 and second positive electrode tabs 112 can be increased, and the total overcurrent area of ​​first negative electrode tabs 121 and second negative electrode tabs 122 can be increased. This can reduce the internal resistance of the battery cell 10, which is beneficial to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway of the battery cell 10, and improve the cycle life and safety of the battery cell 10. Compared to the cell 10 where the positive and negative electrodes are spaced apart along the width direction Z of the electrode assembly, and each layer of positive electrode 110 has a positive electrode tab and each layer of negative electrode 120 has a negative electrode tab, the present application has fewer positive and negative electrodes, which facilitates the fabrication of the positive electrode 110 and the negative electrode 120.

[0090] See Figure 6 and Figure 7 In other embodiments, each positive electrode 110 in the first flat region 101 is provided with a first positive electrode tab 111, each negative electrode 120 in the first flat region 101 is provided with a second negative electrode tab 122, each negative electrode 120 in the second flat region 103 is provided with a first negative electrode tab 121, and each positive electrode 110 in the second flat region 103 is provided with a second positive electrode tab 112.

[0091] By providing a first positive electrode tab 111 for each layer of positive electrode 110 in the first flat region 101, a second negative electrode tab 122 for each layer of negative electrode 120 in the first flat region 101, a first negative electrode tab 121 for each layer of negative electrode 120 in the second flat region 103, and a second positive electrode tab 112 for each layer of positive electrode 110 in the second flat region 103, the number of first positive electrode tabs 111, second positive electrode tabs 112, first negative electrode tabs 121, and second negative electrode tabs 122 can be increased, the total overcurrent area of ​​the first positive electrode tabs 111 and second positive electrode tabs 112 can be increased, and the total overcurrent area of ​​the first negative electrode tabs 121 and second negative electrode tabs 122 can be increased. This can reduce the internal resistance of the battery cell 10, which is beneficial to reducing the temperature rise of the battery cell 10, reducing the risk of thermal runaway of the battery cell 10, and improving the cycle life and safety of the battery cell 10. Compared to the cell 10 where the positive and negative electrodes are spaced apart along the width direction Z of the electrode assembly, and each layer of positive electrode 110 has a positive electrode tab and each layer of negative electrode 120 has a negative electrode tab, the present application has fewer positive and negative electrodes, which facilitates the fabrication of the positive electrode 110 and the negative electrode 120.

[0092] See Figure 1 and Figure 10 , Figure 10 This is a schematic diagram of a partial structure of a battery cell provided in some embodiments of this application.

[0093] In some embodiments, the battery cell 10 further includes a packaging bag 200, which includes a main body 210 and a packaging portion 220. The main body 210 is used to accommodate the electrode assembly 100. The battery cell 10 also includes a first electrical connector 310, a second electrical connector 320, and a first insulating member 410. The first electrical connector 310 is electrically connected to a plurality of first positive electrode tabs 111, and the second electrical connector 320 is electrically connected to a plurality of first negative electrode tabs 121. The first electrical connector 310 and the second electrical connector 320 extend out of the packaging bag 200 through the packaging portion 220. The first insulating member 410 seals the gap between the first electrical connector 310 and the packaging portion 220, and also seals the gap between the second electrical connector 320 and the packaging portion 220. A portion of the first insulating member 410 is located between the first electrical connector 310 and the second electrical connector 320 to isolate the first electrical connector 310 and the second electrical connector 320.

[0094] Compared to the battery cell 10 where the positive and negative electrode tabs are spaced apart along the width direction Z of the electrode assembly, in this application, the upper limit of the width of the tabs along the width direction Z of the electrode assembly is increased, and the upper limit of the width of the first electrical connector 310 and the second electrical connector 320 is also increased. This reduces the thickness requirements for the first electrical connector 310 and the second electrical connector 320, making it easier to bend when connecting the first electrical connector 310 and the second electrical connector 320 to external components. This improves the connection efficiency between the first electrical connector 310 and the second electrical connector 320 and external components, reduces the risk of incomplete soldering when welding the first electrical connector 310 and the second electrical connector 320 to external components, and helps to improve the safety and reliability of electrical equipment.

[0095] By sealing the gap between the first electrical connector 310 and the encapsulation portion 220 and sealing the gap between the second electrical connector 320 and the encapsulation portion 220, a portion of the first insulating member 410 is located between the first electrical connector 310 and the second electrical connector 320 to isolate the first electrical connector 310 and the second electrical connector 320. This facilitates the sealing between the first electrical connector 310, the second electrical connector 320 and the encapsulation portion 220, and ensures that the first electrical connector 310 and the second electrical connector 320 are spaced apart along the thickness direction Y of the electrode assembly, reducing the risk of short circuit between the first electrical connector 310 and the second electrical connector 320 and improving the safety of the battery cell 10.

[0096] In some embodiments, the battery cell 10 further includes a third electrical connector 330, a fourth electrical connector 340, and a second insulating member 420. The third electrical connector 330 is electrically connected to a plurality of second positive electrode tabs 112, and the fourth electrical connector 340 is electrically connected to a plurality of second negative electrode tabs 122. The third electrical connector 330 and the fourth electrical connector 340 extend out of the packaging bag 200 through the encapsulation portion 220. The second insulating member 420 seals the gap between the third electrical connector 330 and the encapsulation portion 220, and seals the gap between the fourth electrical connector 340 and the encapsulation portion 220. A portion of the second insulating member 420 is located between the third electrical connector 330 and the fourth electrical connector 340 to isolate the third electrical connector 330 and the fourth electrical connector 340.

[0097] Compared to the battery cell 10 where the positive and negative electrode tabs are spaced apart along the width direction Z of the electrode assembly, in this application, the upper limit of the width of the electrode tabs along the width direction Z of the electrode assembly is increased, and the upper limit of the width of the third electrical connector 330 and the fourth electrical connector 340 is also increased. This reduces the thickness requirements for the third electrical connector 330 and the fourth electrical connector 340, making it easier to bend when connecting the third electrical connector 330 and the fourth electrical connector 340 to external components. This improves the connection efficiency between the third electrical connector 330 and the fourth electrical connector 340 and external components, reduces the risk of incomplete soldering when welding the third electrical connector 330 and the fourth electrical connector 340 to external components, and helps to improve the safety and reliability of electrical equipment.

[0098] By sealing the gap between the third electrical connector 330 and the encapsulation portion 220 and the gap between the fourth electrical connector 340 and the encapsulation portion 220 with the second insulating member 420 partially located between the third electrical connector 330 and the fourth electrical connector 340 to isolate the third electrical connector 330 and the fourth electrical connector 340, it is possible to facilitate the sealing between the third electrical connector 330, the fourth electrical connector 340 and the encapsulation portion 220, and to maintain a gap between the third electrical connector 330 and the fourth electrical connector 340 along the thickness direction Y of the electrode assembly, thereby reducing the risk of short circuit between the third electrical connector 330 and the fourth electrical connector 340 and improving the safety of the battery cell 10.

[0099] Along the thickness direction Y of the electrode assembly, the projection of the first electrical connector 310 at least partially overlaps with the projection of the second electrical connector 320, and the projection of the third electrical connector 330 at least partially overlaps with the projection of the fourth electrical connector 340.

[0100] Compared to a battery cell 10 with two electrical connectors spaced apart along the width direction Z of the electrode assembly, this application optimizes the electron transport path within the electrode assembly 100 by ensuring that the projections of the first electrical connector 310 and the second electrical connector 320, and the projections of the third electrical connector 330 and the fourth electrical connector 340 at least partially overlap along the thickness direction Y of the electrode assembly. This reduces the internal resistance of the battery cell 10, which in turn reduces the temperature rise of the battery cell 10, decreases the risk of thermal runaway, and improves the cycle life and safety of the battery cell 10. Furthermore, the increased upper limit of the width of each electrical connector along the width direction Z of the electrode assembly reduces the thickness requirements for the electrical connectors, thus improving the energy density of the battery cell 10.

[0101] See Figure 11 , Figure 11 This is a schematic diagram of a portion of the battery cell structure provided in some embodiments of this application from another perspective.

[0102] In some embodiments, along the thickness direction Y of the electrode assembly, the first insulating member 410 includes a first portion 411, a second portion 412, and a third portion 413. The first portion 411 is located between the encapsulation portion 220 and the first electrical connector 310, the second portion 412 is located between the encapsulation portion 220 and the second electrical connector 320, and the third portion 413 is located between the first electrical connector 310 and the second electrical connector 320. Along the length direction X of the electrode assembly, the first electrical connector 310 has a first edge 311 near the first positive electrode tab 111, the second electrical connector 320 has a second edge 321 near the first negative electrode tab 121, and the third portion 413 extends to the first edge 311 and the second edge 321.

[0103] By extending the third portion 413 to the first edge 311 and the second edge 321, the third portion 413 can serve as an insulator for the ends of the first electrical connector 310 and the second electrical connector 320 that are close to the electrode assembly 100, thereby further reducing the risk of short circuit between the first electrical connector 310 and the second electrical connector 320 and improving the safety of the battery cell 10.

[0104] In some embodiments, the thickness of the first portion 411 is H1, where 0.1 mm ≤ H1 ≤ 0.25 mm. For example, H1 can be 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, 0.19 mm, 0.2 mm, 0.22 mm, or 0.25 mm, or a range consisting of any two of these values.

[0105] When H1 is 0.1 mm or equal to 0.1 mm, the insulation and sealing effect between the first part 411 and the encapsulation part 220 and the first electrical connector 310 is better, reducing the risk of short circuit between the first electrical connector 310 and the encapsulation part 220, and also reducing the risk of leakage or external moisture infiltration into the cell 10, which is beneficial to improving the safety of the cell 10. When H1 is less than or equal to 0.25 mm, it is easier for the first part 411 to melt and connect with the encapsulation part 220 and the first electrical connector 310, and it is easier to reduce the space occupied by the first part 411, which is beneficial to improving the energy density of the cell 10. Therefore, when 0.1 mm ≤ H1 ≤ 0.25 mm, it can reduce the risk of short circuit between the first electrical connector 310 and the encapsulation part 220, reduce the risk of leakage or external moisture infiltration into the cell 10, which is beneficial to improving the safety of the cell 10, and it can also facilitate the melting of the first part 411 and its connection with the encapsulation part 220 and the first electrical connector 310, and is beneficial to improving the energy density of the cell 10.

[0106] In some embodiments, the thickness of the second portion 412 is H2, where 0.1 mm ≤ H2 ≤ 0.25 mm. For example, H2 can be 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, 0.19 mm, 0.2 mm, 0.22 mm, or 0.25 mm, or a range consisting of any two of these values.

[0107] When H2 is 0.1 mm or equal to 0.1 mm, the insulation and sealing effect between the second part 412 and the encapsulation part 220 and the second electrical connector 320 is better, reducing the risk of short circuit between the second electrical connector 320 and the encapsulation part 220, and also reducing the risk of leakage or external moisture infiltration into the cell 10, which is beneficial to improving the safety of the cell 10. When H2 is less than or equal to 0.25 mm, it is easier for the second part 412 to melt and connect with the encapsulation part 220 and the second electrical connector 320, and it is easier to reduce the space occupied by the second part 412, which is beneficial to improving the energy density of the cell 10. Therefore, when 0.1 mm ≤ H2 ≤ 0.25 mm, it can reduce the risk of short circuit between the second electrical connector 320 and the encapsulation part 220, reduce the risk of leakage or external moisture infiltration into the cell 10, which is beneficial to improving the safety of the cell 10, and it can also facilitate the melting of the second part 412 and its connection with the encapsulation part 220 and the second electrical connector 320, and is beneficial to improving the energy density of the cell 10.

[0108] In some embodiments, the thickness of the third portion 413 is H3, where 0.1 mm ≤ H3 ≤ 0.25 mm. For example, H2 can be 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, 0.19 mm, 0.2 mm, 0.22 mm, or 0.25 mm, or a range consisting of any two of these values.

[0109] When H3 is 0.1 mm or equal to 0.1 mm, the insulation and sealing effect of the third part 413 on the first electrical connector 310 and the second electrical connector 320 is better, reducing the risk of short circuit between the first electrical connector 310 and the second electrical connector 320, and also reducing the risk of leakage or external moisture infiltration into the cell 10, which is beneficial to improving the safety of the cell 10. When H3 is less than or equal to 0.25 mm, it is easier for the third part 413 to melt and connect with the first electrical connector 310 and the second electrical connector 320, and it is easier to reduce the space occupied by the third part 413, which is beneficial to improving the energy density of the cell 10. Therefore, when 0.1 mm ≤ H3 ≤ 0.25 mm, it can reduce the risk of short circuit between the first electrical connector 310 and the second electrical connector 320, reduce the risk of leakage or external moisture infiltration into the cell 10, which is beneficial to improving the safety of the cell 10, and it can also facilitate the melting of the third part 413 and its connection with the first electrical connector 310 and the second electrical connector 320, which is beneficial to improving the energy density of the cell 10.

[0110] In some embodiments, the cross-sectional area of ​​the first electrical connector 310 perpendicular to the length direction X of the electrode assembly is S1, and the cross-sectional area of ​​the second electrical connector 320 perpendicular to the length direction X of the electrode assembly is S2, where 1 ≤ S1 / S2 ≤ 1.6. For example, S1 / S2 can be 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, or 1.6, or a range consisting of any two of these values.

[0111] Because the materials of the first positive electrode tab 111 and the first negative electrode tab 121 are different, under the condition of the same current-carrying area, the heat generated by the first positive electrode tab 111 during the charging and discharging process of the battery cell 10 will be greater than that generated by the first negative electrode tab 121. When S1 / S2 is greater than or equal to 1, the current-carrying area of ​​the first positive electrode tab 111 is larger than that of the first negative electrode tab 121, improving the current-carrying capacity of the first positive electrode tab 111 and reducing the heat generated by the first positive electrode tab 111. This ensures that the temperature rise of the first positive electrode tab 111 is not too high compared to the temperature rise of the first negative electrode tab 121, thereby reducing the temperature rise difference between the first positive electrode tab 111 and the first negative electrode tab 121. When S1 / S2 is less than or equal to 1.6, the current-carrying area of ​​the first positive electrode tab 111 is not too large, and the temperature rise of the first positive electrode tab 111 is not too low compared to the temperature rise of the first negative electrode tab 121, thus reducing the temperature difference between the first positive electrode tab 111 and the first negative electrode tab 121. The temperature rise difference between the first positive electrode tab 111 and the first negative electrode tab 121 is reduced, thereby reducing the risk of thermal shrinkage of the separator due to excessive local temperature rise in the cell 10. This, in turn, reduces the risk of thermal runaway of the cell 10 caused by short circuit between the positive electrode 110 and the negative electrode 120, and improves the safety of the cell 10. Therefore, when 1≤S1 / S2≤1.6, the temperature rise difference between the first positive electrode tab 111 and the first negative electrode tab 121 can be reduced, thus reducing the risk of thermal shrinkage of the separator due to excessive local temperature rise in the cell 10. This, in turn, reduces the risk of thermal runaway of the cell 10 caused by short circuit between the positive electrode 110 and the negative electrode 120, and improves the safety of the cell 10.

[0112] See Figure 1 and Figure 11 In some embodiments, the width of the battery cell 10 is W0, and the width of the first electrical connector 310 is W1, where 30mm ≤ W1 ≤ W0 - 20mm.

[0113] When W1 is greater than or equal to 30mm, the width of the first electrical connector 310 is not too small, and the current-passing area of ​​the first electrical connector 310 is not too small. This reduces the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway of the battery cell 10, and improve the cycle life and safety of the battery cell 10. When W1 is less than or equal to W0-20mm, it facilitates the sealing between the first electrical connector 310 and the encapsulation part 220, reduces the risk of leakage of the battery cell 10 or the infiltration of external moisture, and helps to improve the safety of the battery cell 10. Therefore, when 30mm≤W1≤W0-20mm, it can reduce the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway of the battery cell 10, and improve the cycle life and safety of the battery cell 10, and also reduces the risk of leakage of the battery cell 10 or the infiltration of external moisture, which helps to improve the safety of the battery cell 10.

[0114] In some embodiments, the width of the second electrical connector 320 is W2, where 30mm ≤ W2 ≤ W0 - 20mm.

[0115] When W2 is greater than or equal to 30mm, the width of the second electrical connector 320 is not too small, and the current-passing area of ​​the second electrical connector 320 is not too small. This reduces the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway of the battery cell 10, and improve the cycle life and safety of the battery cell 10. When W2 is less than or equal to W0-20mm, it facilitates the sealing between the second electrical connector 320 and the encapsulation part 220, reduces the risk of leakage of the battery cell 10 or the infiltration of external moisture, and helps to improve the safety of the battery cell 10. Therefore, when 30mm≤W2≤W0-20mm, it can reduce the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway of the battery cell 10, and improve the cycle life and safety of the battery cell 10, and also reduces the risk of leakage of the battery cell 10 or the infiltration of external moisture, which helps to improve the safety of the battery cell 10.

[0116] See Figure 11 In some embodiments, the thickness of the first electrical connector 310 is H4, where 0.1mm ≤ H4 ≤ 0.8mm. For example, H4 can be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, or 0.8mm, or a range consisting of any two of these values.

[0117] When H4 is greater than or equal to 0.1 mm, the thickness of the first electrical connector 310 is not too small, and the current-passing area of ​​the first electrical connector 310 is not too small. This reduces the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10. When H4 is less than or equal to 0.8 mm, it facilitates the sealing between the first electrical connector 310 and the encapsulation part 220, reduces the risk of leakage or external moisture infiltration of the battery cell 10, and improves the safety of the battery cell 10. Therefore, when 0.1 mm ≤ H4 ≤ 0.8 mm, it can reduce the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10, and also reduces the risk of leakage or external moisture infiltration of the battery cell 10, which helps to improve the safety of the battery cell 10.

[0118] In some embodiments, the thickness of the second electrical connector 320 is H5, where 0.1mm ≤ H5 ≤ 0.7mm. For example, H5 can be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, or 0.7mm, or a range consisting of any two of these values.

[0119] When H5 is greater than or equal to 0.1 mm, the thickness of the second electrical connector 320 is not too small, and the current-passing area of ​​the second electrical connector 320 is not too small. This reduces the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway of the battery cell 10, and improve the cycle life and safety of the battery cell 10. When H5 is less than or equal to 0.7 mm, it facilitates the sealing between the second electrical connector 320 and the encapsulation part 220, reduces the risk of leakage of the battery cell 10 or the infiltration of external moisture, and helps to improve the safety of the battery cell 10. Therefore, when 0.1 mm ≤ H5 ≤ 0.7 mm, it can reduce the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway of the battery cell 10, and improve the cycle life and safety of the battery cell 10, and also reduces the risk of leakage of the battery cell 10 or the infiltration of external moisture, which helps to improve the safety of the battery cell 10.

[0120] See Figure 1 In some embodiments, the width of the battery cell 10 is W0, where 100mm ≤ W0 ≤ 200mm. For example, W0 can be 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, or 200mm, or a range consisting of any two of these values.

[0121] When W0 is greater than or equal to 100mm, the width of the cell 10 is not too small, which is beneficial to improving the energy density of the cell 10. When W0 is less than or equal to 200mm, the width of the cell 10 is not too large, which allows the cell 10 to be used in more types of electrical equipment, thus improving the applicability of the cell 10. Therefore, when 100mm≤W0≤200mm, it is beneficial to both improve the energy density of the cell 10 and make the cell 10 suitable for more types of electrical equipment, thus improving the applicability of the cell 10.

[0122] See Figure 2 and Figure 10 In some embodiments, the width of the first electrical connector 310 is W1, and the width of the first positive electrode tab 111 is C1, where W1-5mm ≤ C1 ≤ W1-2mm. For example, C1 can be W1-5mm, W1-4.5mm, W1-4mm, W1-3.5mm, W1-3mm, W1-2.5mm, or W1-2mm, or a range consisting of any two of these values.

[0123] When C1 is greater than or equal to W1-5mm, the width of the first positive electrode tab 111 is not too small, and the current-carrying area of ​​the first positive electrode tab 111 is not too small. This reduces the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10. When C1 is less than or equal to W1-2mm, it is easier to bend and fold multiple first positive electrode tabs 111 and connect them to the first electrical connector 310, which helps to improve the manufacturing efficiency of the battery cell 10. Therefore, when W1-5mm≤C1≤W1-2mm, it can not only reduce the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10, but also facilitates the bending and folding of multiple first positive electrode tabs 111 and connection to the first electrical connector 310, which helps to improve the manufacturing efficiency of the battery cell 10.

[0124] In some embodiments, the width of the second electrical connector 320 is W2, and the width of the first negative electrode tab 121 is C2, where W2-5mm ≤ C2 ≤ W2-2mm. For example, C2 can be W2-5mm, W2-4.5mm, W2-4mm, W2-3.5mm, W2-3mm, W2-2.5mm, or W2-2mm, or a range consisting of any two of these values.

[0125] When C2 is greater than or equal to W2-5mm, the width of the first negative electrode tab 121 is not too small, and the current-carrying area of ​​the first negative electrode tab 121 is not too small. This reduces the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10. When C2 is less than or equal to W2-2mm, it is easier to bend and fold multiple first negative electrode tabs 121 and connect them to the second electrical connector 320, which helps to improve the manufacturing efficiency of the battery cell 10. Therefore, when W2-5mm≤C2≤W2-2mm, it can not only reduce the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10, but also facilitates the bending and folding of multiple first negative electrode tabs 121 and their connection to the second electrical connector 320, which helps to improve the manufacturing efficiency of the battery cell 10.

[0126] See Figure 3 and Figure 10 In some embodiments, the width of the third electrical connector 330 is W3, and the width of the second positive electrode tab 112 is C3, where W3-5mm ≤ C3 ≤ W3-2mm. For example, C3 can be W3-5mm, W3-4.5mm, W3-4mm, W3-3.5mm, W3-3mm, W3-2.5mm, or W3-2mm, or a range consisting of any two of these values.

[0127] When C3 is greater than or equal to W3-5mm, the width of the second positive electrode tab 112 is not too small, and the current-carrying area of ​​the second positive electrode tab 112 is not too small. This reduces the internal resistance of the cell 10, which helps to reduce the temperature rise of the cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the cell 10. When C3 is less than or equal to W3-2mm, it is easier to bend and fold multiple second positive electrode tabs 112 and connect them to the third electrical connector 330, which helps to improve the manufacturing efficiency of the cell 10. Therefore, when W3-5mm≤C3≤W3-2mm, it can not only reduce the internal resistance of the cell 10, which helps to reduce the temperature rise of the cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the cell 10, but also facilitates the bending and folding of multiple second positive electrode tabs 112 and their connection to the third electrical connector 330, which helps to improve the manufacturing efficiency of the cell 10.

[0128] In some embodiments, the width of the fourth electrical connector 340 is W4, and the width of the second negative electrode tab 122 is C4, where W4-5mm ≤ C4 ≤ W4-2mm. For example, C4 can be W4-5mm, W4-4.5mm, W4-4mm, W4-3.5mm, W4-3mm, W4-2.5mm, or W4-2mm, or a range consisting of any two of these values.

[0129] When C4 is greater than or equal to W4-5mm, the width of the second negative electrode tab 122 is not too small, and the current-carrying area of ​​the second negative electrode tab 122 is not too small. This reduces the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10. When C4 is less than or equal to W4-2mm, it is easier to bend and fold multiple second negative electrode tabs 122 and connect them to the fourth electrical connector 340, which helps to improve the manufacturing efficiency of the battery cell 10. Therefore, when W4-5mm≤C4≤W4-2mm, it can not only reduce the internal resistance of the battery cell 10, which helps to reduce the temperature rise of the battery cell 10, reduce the risk of thermal runaway, and improve the cycle life and safety of the battery cell 10, but also facilitates the bending and folding of multiple second negative electrode tabs 122 and their connection to the fourth electrical connector 340, which helps to improve the manufacturing efficiency of the battery cell 10.

[0130] See Figure 10 In some embodiments, along the width direction Z of the electrode assembly, the width of the first electrical connector 310 is W1, the width of the second electrical connector 320 is W2, and the width of the first insulating member 410 is W5, where W5 ≥ W1 and W5 ≥ W2. For example, W5 can be W1, 1.1W1, 1.2W1, 1.3W1, 1.4W1, 1.5W1, 1.6W1, 1.7W1, 1.8W1, 1.9W1, or 2W1, etc. For example, W5 can be W2, 1.1W2, 1.2W2, 1.3W2, 1.4W2, 1.5W2, 1.6W2, 1.7W2, 1.8W2, 1.9W2, or 2W2, etc.

[0131] By ensuring that W5≥W1 and W5≥W2, the first insulating member 410 can cover the first electrical connector 310 and the second electrical connector 320 in the width direction Z of the electrode assembly. This results in better insulation and sealing between the first electrical connector 310 and the encapsulation portion 220, and between the second electrical connector 320 and the encapsulation portion 220. This reduces the risk of short circuits between the first electrical connector 310 and the encapsulation portion 220, and between the second electrical connector 320 and the encapsulation portion 220. It also reduces the risk of leakage or infiltration of external moisture into the cell 10, thus improving the safety of the cell 10.

[0132] In some embodiments, 4mm ≤ W5-W1 ≤ 10mm, and 4mm ≤ W5-W2 ≤ 10mm. For example, W5-W1 can be 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm, or a range consisting of any two of these values. For example, W5-W2 can be 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm, or a range consisting of any two of these values.

[0133] When W5-W1 is greater than or equal to 4mm and W5-W2 is greater than or equal to 4mm, the first insulating member 410 can cover the first electrical connector 310 and the second electrical connector 320 in the width direction Z of the electrode assembly. This improves the insulation and sealing effect of the first insulating member 410 between the first electrical connector 310 and the encapsulation portion 220, and between the second electrical connector 320 and the encapsulation portion 220, thereby reducing the distance between the first electrical connector 310 and the encapsulation portion 220, and between the second electrical connector 320 and the encapsulation portion 220. The risk of short circuits is reduced, and the risk of leakage or external moisture infiltration into the cell 10 is also reduced, which is beneficial to improving the safety of the cell 10. When W5-W1 is less than or equal to 10mm and W5-W2 is less than or equal to 10mm, the space occupied by the first insulating component 410 will not be too large, which is beneficial to improving the energy density of the cell 10. Therefore, when 4mm≤W5-W1≤10mm and 4mm≤W5-W2≤10mm, both the safety and energy density of the cell 10 can be improved.

[0134] In some embodiments, the sum of the cross-sectional area of ​​the first electrical connector 310 perpendicular to the length direction X of the electrode assembly and the cross-sectional area of ​​the third electrical connector 330 perpendicular to the length direction X of the electrode assembly is S3 (in mm). 2 ), 20%≤5A / mm 2 ×S3 / (E×C)≤50%. Where E is the rated capacity of cell 10 (in Ah), and C is the maximum discharge rate of cell 10 (in 1 / h). For example, 5A / mm 2 ×S3 / (E×C) can be 20%, 22%, 25%, 28%, 30%, 32%, 35%, 37%, 40%, 43%, 45%, 48%, or 50%, or a range of any two of these values.

[0135] The first electrical connector 310 and the third electrical connector 330 are made of the same material as the positive electrode tab, namely aluminum, and aluminum has a current carrying capacity of 5A / mm². 2 5A / mm 2×S3 represents the total current-carrying capacity of the first electrical connector 310 and the third electrical connector 330, and E×C represents the discharge current of the cell 10. (When 5A / mm) 2 ×S3 / (E×C) is greater than or equal to 20%, ensuring that the total current-carrying capacity of the first electrical connector 310 and the third electrical connector 330 is not too small, reducing the risk of overheating of the first electrical connector 310 and the third electrical connector 330, reducing the risk of thermal runaway of the battery cell 10, and improving the cycle life and safety of the battery cell 10; when 5A / mm 2 ×S3 / (E×C) is less than or equal to 50%, ensuring that the total current-carrying capacity of the first electrical connector 310 and the third electrical connector 330 is not too large, and the cross-sectional area of ​​the first electrical connector 310 and / or the third electrical connector 330 is not too large, thus reducing the space occupied by the first electrical connector 310 and / or the third electrical connector 330, which is beneficial to improving the energy density of the battery cell 10; therefore, when 20%≤5A / mm 2 ×S3 / (E×C)≤50% can reduce the risk of thermal runaway of cell 10, improve the cycle life and safety of cell 10, and also help to improve the energy density of cell 10.

[0136] In some embodiments, the sum of the cross-sectional area of ​​the second electrical connector 320 perpendicular to the length direction X of the electrode assembly and the cross-sectional area of ​​the fourth electrical connector 340 perpendicular to the length direction X of the electrode assembly is S4 (in mm). 2 ), 20%≤8 A / mm 2 ×S4 / (E×C)≤50%. Where E is the rated capacity of cell 10, and C is the maximum discharge rate of cell 10. For example, 8 A / mm². 2 ×S4 / (E×C) can be 20%, 22%, 25%, 28%, 30%, 32%, 35%, 37%, 40%, 43%, 45%, 48%, or 50%, or a range of any two of these values.

[0137] The second electrical connector 320 and the fourth electrical connector 340 are made of the same material as the negative electrode tab, namely copper, and the current carrying capacity of copper is 8A / mm². 2 8A / mm 2 ×S4 represents the total current-carrying capacity of the second electrical connector 320 and the fourth electrical connector 340, and E×C represents the discharge current of the cell 10. (When 8A / mm) 2 ×S4 / (E×C) is greater than or equal to 20%, ensuring that the total current-carrying capacity of the second electrical connector 320 and the fourth electrical connector 340 is not too small, reducing the risk of overheating of the second electrical connector 320 and the fourth electrical connector 340, reducing the risk of thermal runaway of the battery cell 10, and improving the cycle life and safety of the battery cell 10; when 8 A / mm 2×S4 / (E×C) is less than or equal to 50%, ensuring that the total current-carrying capacity of the second electrical connector 320 and the fourth electrical connector 340 is not too large, and that the cross-sectional area of ​​the second electrical connector 320 and / or the fourth electrical connector 340 is not too large, thus reducing the space occupied by the second electrical connector 320 and / or the fourth electrical connector 340, which is beneficial for improving the energy density of the battery cell 10; therefore, when 20%≤8 A / mm 2 ×S4 / (E×C)≤50% can reduce the risk of thermal runaway of cell 10, improve the cycle life and safety of cell 10, and also help to improve the energy density of cell 10.

[0138] In some embodiments, the sum of the cross-sectional areas of the plurality of first positive electrode tabs 111 perpendicular to the length direction X of the electrode assembly and the cross-sectional areas of the plurality of second positive electrode tabs 112 perpendicular to the length direction X of the electrode assembly is S5 (in mm). 2 ), 20%≤5 A / mm 2 ×S5 / (E×C)≤50%. Where E is the rated capacity of cell 10, and C is the maximum discharge rate of cell 10. For example, 5 A / mm². 2 ×S5 / (E×C) can be 20%, 22%, 25%, 28%, 30%, 32%, 35%, 37%, 40%, 43%, 45%, 48%, or 50%, or a range of any two of these values.

[0139] The first positive electrode tab 111 and the second positive electrode tab 112 are made of aluminum, and aluminum has a current carrying capacity of 5A / mm². 2 5A / mm 2 ×S5 represents the total current conductivity of the multiple first positive electrode tabs 111 and the multiple second positive electrode tabs 112, and E×C represents the discharge current of the cell 10. (When 5A / mm²) 2 ×S5 / (E×C) is greater than or equal to 20%, ensuring that the total current conductivity of the multiple first positive electrode tabs 111 and multiple second positive electrode tabs 112 is not too small, reducing the risk of overheating of the first positive electrode tabs 111 and the second positive electrode tabs 112, reducing the risk of thermal runaway of the cell 10, and improving the cycle life and safety of the cell 10; when 5A / mm 2 ×S5 / (E×C) is less than or equal to 50%, ensuring that the total current conductivity of the multiple first positive electrode tabs 111 and the multiple second positive electrode tabs 112 is not too large, and the cross-sectional area of ​​the first positive electrode tabs 111 and / or the second positive electrode tabs 112 is not too large, thus reducing the space occupied by the first positive electrode tabs 111 and / or the second positive electrode tabs 112, which is beneficial to improving the energy density of the cell 10; therefore, when 20%≤5A / mm 2×S5 / (E×C)≤50% can reduce the risk of thermal runaway of cell 10, improve the cycle life and safety of cell 10, and also help to improve the energy density of cell 10.

[0140] In some embodiments, the width C1 of the first positive electrode tab 111 is equal to the width C3 of the second positive electrode tab 112, the total number of the first positive electrode tab 111 and the second positive electrode tab 112 is N1, the thickness T1 of the first positive electrode tab 111 is equal to the thickness T2 of the second positive electrode tab 112, and S5 = C1 × T1 × N1, that is, 20% ≤ 5 A / mm 2 ×C1×T1×N1 / (E×C)≤50%.

[0141] In some embodiments, the sum of the cross-sectional areas of the plurality of first negative electrode tabs 121 perpendicular to the length direction X of the electrode assembly and the cross-sectional areas of the plurality of second negative electrode tabs 122 perpendicular to the length direction X of the electrode assembly is S6 (in mm). 2 ), 20%≤8 A / mm 2 ×S6 / (E×C)≤50%. Where E is the rated capacity of cell 10, and C is the maximum discharge rate of cell 10. For example, 8 A / mm². 2 ×S6 / (E×C) can be 20%, 22%, 25%, 28%, 30%, 32%, 35%, 37%, 40%, 43%, 45%, 48%, or 50%, or a range of any two of these values.

[0142] The first negative electrode tab 121 and the second negative electrode tab 122 are made of copper, and the current carrying capacity of copper is 8 A / mm². 2 8A / mm 2 ×S6 represents the total current conductivity of the multiple first negative electrode tabs 121 and the multiple second negative electrode tabs 122, and E×C represents the discharge current of the cell 10. (When 8A / mm) 2 ×S6 / (E×C) is greater than or equal to 20%, ensuring that the total current conductivity of the multiple first negative electrode tabs 121 and multiple second negative electrode tabs 122 is not too small, reducing the risk of overheating of the first negative electrode tabs 121 and second negative electrode tabs 122, reducing the risk of thermal runaway of the battery cell 10, and improving the cycle life and safety of the battery cell 10; when 8 A / mm 2 ×S6 / (E×C) is less than or equal to 50%, ensuring that the total current-carrying capacity of the multiple first negative electrode tabs 121 and multiple second negative electrode tabs 122 is not too large, and the cross-sectional area of ​​the first negative electrode tabs 121 and / or the second negative electrode tabs 122 is not too large, thus reducing the space occupied by the first negative electrode tabs 121 and / or the second negative electrode tabs 122, which is beneficial to improving the energy density of the cell 10; therefore, when 20%≤8 A / mm 2×S6 / (E×C)≤50% can reduce the risk of thermal runaway of cell 10, improve the cycle life and safety of cell 10, and also help to improve the energy density of cell 10.

[0143] In some embodiments, the width C2 of the first negative electrode tab 121 is equal to the width C4 of the second negative electrode tab 122, the total number of the first negative electrode tabs 121 and the second negative electrode tabs 122 is N2, the thickness T3 of the first negative electrode tab 121 is equal to the thickness T4 of the second negative electrode tab 122, and S6 = C2 × T2 × N2, i.e., 20% ≤ 8 A / mm 2 ×C2×T2×N2 / (E×C)≤50%.

[0144] Referring to Table 1, W1 is the width of the first electrical connector; W3 is the width of the third electrical connector; H4 is the thickness of the first electrical connector; H6 is the thickness of the third electrical connector; S3 is the sum of the cross-sectional areas of the first electrical connector perpendicular to the length direction of the electrode assembly and the cross-sectional areas of the third electrical connector perpendicular to the length direction of the electrode assembly; W2 is the width of the second electrical connector; W4 is the width of the fourth electrical connector; H5 is the thickness of the second electrical connector; H7 is the thickness of the fourth electrical connector; S4 is the sum of the cross-sectional areas of the second electrical connector perpendicular to the length direction of the electrode assembly and the cross-sectional areas of the fourth electrical connector perpendicular to the length direction of the electrode assembly; C1 is the width of the first positive electrode tab; C2 is the width of the second positive electrode tab; C3 is the width of the first negative electrode tab; C4 is the width of the second negative electrode tab; N1 is the total number of the first positive electrode tab and the second positive electrode tab; N2 is the total number of the first negative electrode tab and the second negative electrode tab. The embodiments and comparative examples in Table 1 share some of the following parameters: cell width W0 = 115 mm, cell aspect ratio 2.78, cell rated capacity E = 42 Ah, cell maximum discharge rate C = 12 C; the thicknesses H4 and H6 of the first and third electrical connectors are both 0.5 mm, the thicknesses H5 and H7 of the second and fourth electrical connectors are both 0.3 mm, the widths of the first and second positive electrode tabs are both 28 mm, the widths of the third and fourth positive electrode tabs are both 28 mm, the thicknesses of the first and second positive electrode tabs are both 15 μm, and the thicknesses of the first and second negative electrode tabs are both 8 μm.

[0145] The battery cell of Comparative Example 1 includes one positive electrode connector and one negative electrode connector. Multiple first positive electrode tabs (116 in number) and multiple first negative electrode tabs (120 in number) are provided at one end of the electrode assembly along its length. The multiple first positive electrode tabs are connected to the positive electrode connector, and the multiple first negative electrode tabs are connected to the negative electrode connector. The first positive and first negative electrode tabs are spaced apart along the width direction of the electrode assembly. No tabs are provided at the other end of the electrode assembly along its length. The battery cell of Comparative Example 2 includes one positive electrode connector and one negative electrode connector. Multiple first positive electrode tabs (116 in number) are provided at one end of the electrode assembly along its length, and multiple first negative electrode tabs (120 in number) are provided at the other end. The multiple first positive electrode tabs are connected to the positive electrode connector, and the multiple first negative electrode tabs are connected to the negative electrode connector. Examples 1 to 6 each include two positive electrode connectors and two negative electrode connectors. In the battery cell of Example 1, one end of the electrode assembly along its length is provided with multiple first positive electrode tabs (58 in number) and multiple first negative electrode tabs (60 in number), and the other end is provided with multiple second positive electrode tabs (58 in number) and multiple second negative electrode tabs (60 in number). The multiple first positive electrode tabs are connected to one of the positive electrode connectors, the multiple second positive electrode tabs are connected to another positive electrode connector, the multiple first negative electrode tabs are connected to one of the negative electrode connectors, and the multiple second negative electrode tabs are connected to another negative electrode connector. Furthermore, along the thickness direction of the electrode assembly, the projections of the first positive electrode tabs and the projections of the first negative electrode tabs at least partially overlap. The projections of the two positive electrode tabs at least partially overlap with the projection of the second negative electrode tab; in the cell of Embodiment 1, the first positive electrode tab is connected to the first flat region, the first negative electrode tab is connected to the second flat region, the second positive electrode tab is connected to the first flat region, and the second negative electrode tab is connected to the second flat region; in the cell of Embodiment 2, the first positive electrode tab is connected to the first flat region, the first negative electrode tab is connected to the second flat region, the second positive electrode tab is connected to the second flat region, and the second negative electrode tab is connected to the first flat region; in the cells of Embodiments 3 to 6, the structure of the electrode tabs is the same as that of Embodiment 1, except that W1, W2, W3 or W4 are adjusted, thereby adjusting the ratio of the cross-sectional area of ​​the electrical connector to EC, and the test data of the cell temperature and temperature rise are listed in Table 1.

[0146] Table 1 Temperature test of battery cells

[0147] Test method for cell temperature: (1) Along the length of the electrode assembly, attach a first temperature sensing wire to the middle of the first end (position 1) of the cell corresponding to the electrode plate; attach a second temperature sensing wire to the middle of the cell (position 2) along the length of the electrode assembly; attach a third temperature sensing wire to the middle of the second end (position 3) of the cell corresponding to the electrode plate along the length of the electrode assembly.

[0148] (2) Place the battery cell in an environment of 25°C for 15 minutes. Charge the battery cell at a constant current of 6.5C to 4.35V, and then charge it at a constant voltage of 4.35V to 0.05C. After standing for 120 minutes, discharge it at a constant current of 0.5C to 3.0V and then stand for 30 minutes.

[0149] (3) The battery cell is then charged at a constant current of 6.5C to 4.35V, and then charged at a constant voltage of 4.35V to 30A. After standing for 120 minutes, it is discharged at a constant current of 12C to 3.0V and then left to stand for 120 minutes.

[0150] (4) Repeat step 3 three times, and let the battery cell stand for 5 minutes.

[0151] (5) Record the temperature at the tab and the middle of the cell during the charging and discharging process using three temperature sensing wires. The highest value among all temperatures is the highest temperature of the cell. The temperature difference at each location = the highest temperature at that location during the charging and discharging process - the lowest temperature at that location during the charging and discharging process.

[0152] In Comparative Example 1, along the length of the electrode assembly, the first temperature sensing wire is located at the middle of the end of the cell corresponding to the electrode plate near the first positive and first negative electrode tabs (position 1), the second temperature sensing wire is located in the middle of the cell (position 2), and the third temperature sensing wire is located at the middle of the end of the cell corresponding to the electrode plate away from the first positive and first negative electrode tabs (position 3). In Comparative Example 2, along the length of the electrode assembly, the first temperature sensing wire is located at the middle of the end of the cell corresponding to the electrode plate near the first positive electrode tab (position 1), the second temperature sensing wire is located in the middle of the cell (position 2), and the third temperature sensing wire is located at the middle of the end of the cell corresponding to the electrode plate near the first negative electrode tab (position 3).

[0153] Based on Table 1, the following conclusions can be drawn: (1) Referring to Comparative Examples 1-2 and Examples 1-6, this application optimizes the electron transport path inside the electrode assembly, reduces the internal resistance of the battery cell, and helps to reduce the temperature rise of the battery cell, reduce the risk of thermal runaway of the battery cell, and improve the cycle life and safety of the battery cell by making the positive electrode sheet include a plurality of first positive electrode tabs and a plurality of second positive electrode tabs, and the negative electrode sheet include a plurality of first negative electrode tabs and a plurality of second negative electrode tabs. The first positive electrode tabs and the first negative electrode tabs are located at one end of the electrode assembly along its length direction, and the second positive electrode tabs and the second negative electrode tabs are located at the other end of the electrode assembly along its length direction. Along the thickness direction of the electrode assembly, the projection of the first positive electrode tabs and the projection of the first negative electrode tabs overlap at least partially, and the projection of the second positive electrode tabs and the projection of the second negative electrode tabs overlap at least partially.

[0154] (2) Referring to Comparative Examples 1-2 and Examples 3-6, the width of the positive electrode electrical connector (first electrical connector, third electrical connector) or negative electrode electrical connector (second electrical connector, fourth electrical connector) in this application can be set to be larger, so that the current-passing area of ​​the positive electrode electrical connector or negative electrode electrical connector is larger, thereby improving the current-passing capacity of the battery cell, reducing the internal resistance of the battery cell, which is beneficial to reducing the temperature rise of the battery cell, reducing the risk of thermal runaway of the battery cell, and improving the cycle life and safety of the battery cell.

[0155] (3) Refer to Examples 1-5, when 5A / mm 2 If ×S3 / (E×C) is less than 20%, the total current-carrying capacity of the first and third electrical connectors is too small, which will increase the temperature rise of the battery cell and affect its cycle life and safety; when 20% ≤ 5A / mm 2 The result of ×S3 / (E×C)≤50% is that the total current conduction capacity of the first and third electrical connectors is strong, which can reduce the temperature rise of the battery cell, reduce the risk of thermal runaway of the battery cell, improve the cycle life and safety of the battery cell, and also help to improve the energy density of the battery cell.

[0156] (4) Refer to Examples 1-4 and Example 6, when 8A / mm 2 If ×S4 / (E×C) is less than 20%, the total current conductivity of the second and fourth electrical connectors is too low, which will increase the temperature rise of the battery cell and affect its cycle life and safety; when 20% ≤ 8A / mm 2 The result of ×S4 / (E×C)≤50% is that the total current conduction capacity of the second and fourth electrical connectors is strong, which can reduce the temperature rise of the battery cell, reduce the risk of thermal runaway of the battery cell, improve the cycle life and safety of the battery cell, and also help to improve the energy density of the battery cell.

[0157] This application provides an electrical device, including a battery cell 10 as described above, the battery cell 10 being used to provide electrical energy.

[0158] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0159] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, The battery cell includes an electrode assembly, which includes a positive electrode plate and a negative electrode plate. The positive electrode plate includes a plurality of first positive electrode tabs and a plurality of second positive electrode tabs, and the negative electrode plate includes a plurality of first negative electrode tabs and a plurality of second negative electrode tabs. The first positive electrode tabs and the first negative electrode tabs are located at one end of the electrode assembly along its length, and the second positive electrode tabs and the second negative electrode tabs are located at the other end of the electrode assembly along its length. Along the thickness direction of the electrode assembly, the projection of the first positive electrode tab at least partially overlaps with the projection of the first negative electrode tab, and the projection of the second positive electrode tab at least partially overlaps with the projection of the second negative electrode tab.

2. The battery cell according to claim 1, characterized in that, The electrode assembly is a wound structure, comprising a first straight region, a first corner region, a second straight region, and a second corner region connected sequentially in its winding direction. The first straight region and the second straight region are arranged opposite to each other in the thickness direction of the electrode assembly, and the first corner region and the second corner region are arranged opposite to each other in the width direction of the electrode assembly. The length direction of the electrode assembly is parallel to the winding axis direction of the electrode assembly. The first positive electrode tab is connected to the first flat region, the first negative electrode tab is connected to the second flat region, the second positive electrode tab is connected to the first flat region, and the second negative electrode tab is connected to the second flat region; or, The first positive electrode tab is connected to the first flat region, the first negative electrode tab is connected to the second flat region, the second positive electrode tab is connected to the second flat region, and the second negative electrode tab is connected to the first flat region.

3. The battery cell according to claim 2, characterized in that, Each layer of positive electrode sheet in the first flat region is provided with a first positive electrode tab and a second positive electrode tab, and each layer of negative electrode sheet in the second flat region is provided with a first negative electrode tab and a second negative electrode tab.

4. The battery cell according to claim 2, characterized in that, Each layer of positive electrode sheet in the first flat region is provided with a first positive electrode tab, each layer of negative electrode sheet in the first flat region is provided with a second negative electrode tab, each layer of negative electrode sheet in the second flat region is provided with a first negative electrode tab, and each layer of positive electrode sheet in the second flat region is provided with a second positive electrode tab.

5. The battery cell according to claim 1, characterized in that, The battery cell also includes a packaging bag, which includes a main body and a packaging part, the main body being used to accommodate the electrode assembly; The battery cell further includes a first electrical connector, a second electrical connector, and a first insulating member. The first electrical connector is electrically connected to a plurality of first positive electrode tabs, and the second electrical connector is electrically connected to a plurality of first negative electrode tabs. The first electrical connector and the second electrical connector extend out of the packaging bag through the encapsulation portion. The first insulating member seals the gap between the first electrical connector and the encapsulation portion, and also seals the gap between the second electrical connector and the encapsulation portion. A portion of the first insulating member is located between the first electrical connector and the second electrical connector to isolate the first electrical connector and the second electrical connector. The battery cell further includes a third electrical connector, a fourth electrical connector, and a second insulating member. The third electrical connector is electrically connected to a plurality of second positive electrode tabs, and the fourth electrical connector is electrically connected to a plurality of second negative electrode tabs. The third and fourth electrical connectors extend out of the packaging bag through the encapsulation portion. The second insulating member seals the gap between the third electrical connector and the encapsulation portion, and seals the gap between the fourth electrical connector and the encapsulation portion. A portion of the second insulating member is located between the third and fourth electrical connectors to isolate the third and fourth electrical connectors.

6. The battery cell according to claim 5, characterized in that, Along the thickness direction of the electrode assembly, the first insulating member includes a first part, a second part, and a third part, wherein the first part is located between the encapsulation part and the first electrical connector, the second part is located between the encapsulation part and the second electrical connector, and the third part is located between the first electrical connector and the second electrical connector; Along the length of the electrode assembly, the first electrical connector has a first edge near the first positive electrode tab, the second electrical connector has a second edge near the first negative electrode tab, and the third portion extends to the first and second edges.

7. The battery cell according to claim 6, characterized in that, The battery cell must meet at least one of the following conditions: (1) The thickness of the first part is H1, 0.1mm≤H1≤0.25mm; (2) The thickness of the second part is H2, 0.1mm≤H2≤0.25mm; (3) The thickness of the third part is H3, 0.1mm≤H3≤0.25mm.

8. The battery cell according to claim 5, characterized in that, The cross-sectional area of ​​the first electrical connector perpendicular to the length direction of the electrode assembly is S1, and the cross-sectional area of ​​the second electrical connector perpendicular to the length direction of the electrode assembly is S2, where 1≤S1 / S2≤1.

6.

9. The battery cell according to claim 5, characterized in that, The battery cell must meet at least one of the following conditions: (1) The width of the battery cell is W0, and the width of the first electrical connector is W1, 30mm≤W1≤W0-20mm; (2) The width of the second electrical connector is W2, 30mm≤W2≤W0-20mm; (3) The thickness of the first electrical connector is H4, 0.1mm≤H4≤0.8mm; (4) The thickness of the second electrical connector is H5, 0.1mm≤H5≤0.7mm; (5) The width W0 of the battery cell is 100mm≤W0≤200mm.

10. The battery cell according to claim 5, characterized in that, The battery cell must meet at least one of the following conditions: (1) The width of the first electrical connector is W1, and the width of the first positive electrode tab is C1, where W1-5mm≤C1≤W1-2mm; (2) The width of the second electrical connector is W2, and the width of the first negative electrode tab is C2, where W2-5mm≤C2≤W2-2mm; (3) The width of the third electrical connector is W3, and the width of the second positive electrode tab is C3, where W3-5mm≤C3≤W3-2mm; (4) The width of the fourth electrical connector is W4, and the width of the second negative electrode tab is C4, where W4-5mm≤C4≤W4-2mm.

11. The battery cell according to claim 5, characterized in that, Along the width direction of the electrode assembly, the width of the first electrical connector is W1, the width of the second electrical connector is W2, and the width of the first insulating member is W5, where W5 ≥ W1 and W5 ≥ W2; preferably, 4mm ≤ W5 - W1 ≤ 10mm and 4mm ≤ W5 - W2 ≤ 10mm.

12. The battery cell according to claim 5, characterized in that, The sum of the cross-sectional area of ​​the first electrical connector perpendicular to the length direction of the electrode assembly and the cross-sectional area of ​​the third electrical connector perpendicular to the length direction of the electrode assembly is S3, 20%≤5A / mm. 2 ×S3 / (E×C)≤50%; and / or, The sum of the cross-sectional area of ​​the second electrical connector perpendicular to the length direction of the electrode assembly and the cross-sectional area of ​​the fourth electrical connector perpendicular to the length direction of the electrode assembly is S4, 20% ≤ 8 A / mm. 2 ×S4 / (E×C)≤50%; Where E is the rated capacity of the battery cell, and C is the maximum discharge rate of the battery cell.

13. The battery cell according to claim 1, characterized in that, The sum of the cross-sectional areas of the plurality of first positive electrode tabs perpendicular to the length direction of the electrode assembly and the cross-sectional areas of the plurality of second positive electrode tabs perpendicular to the length direction of the electrode assembly is S5, 20%≤5 A / mm 2 ×S5 / (E×C)≤50%; and / or, The sum of the cross-sectional areas of the plurality of first negative electrode tabs perpendicular to the length direction of the electrode assembly and the cross-sectional areas of the plurality of second negative electrode tabs perpendicular to the length direction of the electrode assembly is S6, 20%≤8 A / mm 2 ×S6 / (E×C)≤50%; Where E is the rated capacity of the battery cell, and C is the maximum discharge rate of the battery cell.

14. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-13, the battery cell being used to provide electrical energy.

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