Battery cell and battery

Abstract

The utility model provides a battery cell and a battery, and belongs to the technical field of lithium ion batteries. The battery cell comprises a positive plate, a negative plate and a diaphragm, the positive plate, the diaphragm and the negative plate are sequentially stacked, the positive plate comprises a positive current collector and a positive active material layer, positive paste areas are arranged on the two opposite sides of the positive current collector in the thickness direction of the battery cell, and the positive paste areas are covered with the positive active material layer; the negative plate comprises a negative current collector and a negative active material layer, the negative current collector is provided with a first side and a second side which are opposite to each other along the thickness direction of the battery cell, the first side of the negative current collector comprises a first negative empty foil area and a first negative paste area, the negative active material layer covers the first negative paste area, and the second side of the negative current collector is provided with a second negative foil area. The first negative electrode empty foil region is not coated with a negative electrode active material layer, and the first negative electrode empty foil region is arranged around the peripheral side of the first negative electrode paste region. According to the technical scheme, the high energy density and the fast charging performance of the battery can be considered, and the comprehensive performance is good.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion batteries, in particular to a battery core and a battery. Background Art

[0002] Lithium-ion battery is a general term for batteries with lithium-ion embedded compounds as positive electrode materials. It is a secondary battery (rechargeable battery) that mainly relies on the movement of lithium ions between the positive and negative electrodes to work. Lithium-ion batteries have advantages such as high voltage platform, high energy density and long cycle life, making them the main energy source in the consumer electronics and electric fields. Lithium-ion power batteries are currently gradually developing towards high safety, long battery life and fast charging.

[0003] Blade batteries made using the lamination process can discharge at high power to the greatest extent, with improved heat dissipation and better current density consistency. Compared with ordinary batteries, blade batteries have better safety characteristics, energy density, and cycle characteristics, so they are gradually being promoted and applied. However, there is still the problem of not being able to take into account both the high energy density and fast charging performance of the battery.

[0004] Accordingly, the art needs a new technical solution to solve the above problems. Utility Model Content

[0005] At least one technical problem to be solved by the present invention is that the existing laminated long blade battery cannot take into account both the high energy density and fast charging performance of the battery.

[0006] In order to solve the above technical problems, in a first aspect, an embodiment of the present utility model provides a battery cell, comprising: a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence.

[0007] The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer. Along the thickness direction of the battery cell, positive electrode paste areas are arranged on opposite sides of the positive electrode current collector, and the positive electrode active material layer covers the positive electrode paste areas.

[0008] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. Along the thickness direction of the battery cell, the negative electrode current collector has a first side and a second side opposite to each other. The first side of the negative electrode current collector includes a first negative electrode empty foil area and a first negative electrode pasted area. The negative electrode active material layer covers the first negative electrode pasted area. The first negative electrode empty foil area is not coated with the negative electrode active material layer. The first negative electrode empty foil area is arranged around the circumference of the first negative electrode pasted area.

[0009] In some embodiments, the second side of the negative current collector includes a second negative paste area and a second negative bare foil area. The negative active material coating covers the second negative paste area, and the second negative bare foil area is not coated with the negative active material layer. The second negative bare foil area is disposed around the circumferential side of the second negative paste area.

[0010] In some embodiments, along the first direction, the ratio of the size of the negative current collector to the size of the first negative paste area is 1.0005 - 1.007, and the ratio of the size of the negative current collector to the size of the second negative paste area is 1.0005 - 1.007.

[0011] In some embodiments, along the second direction, the ratio of the size of the negative current collector to the size of the first negative paste area is 1.005 - 1.05, and the ratio of the size of the negative current collector to the size of the second negative paste area is 1.005 - 1.05; wherein, the first direction is perpendicular to the second direction.

[0012] In some embodiments, the first negative bare foil area has a first area, a second area, a third area, and a fourth area that are sequentially connected end to end. The first area and the third area are opposite to each other along the second direction and extend along the first direction. The second area and the fourth area are opposite to each other along the first direction and extend along the second direction, where

[0013] the difference in width between any two areas is within 10%.

[0014] In some embodiments, in the first direction, a first tab is provided at the first end of the positive electrode sheet, a second tab is provided at the second end of the positive electrode sheet, a third tab is provided at the first end of the negative electrode sheet, and a fourth tab is provided at the second end of the negative electrode sheet; where

[0015] the first tab and the second tab are electrically connected to the positive current collector, and the third tab and the fourth tab are electrically connected to the negative current collector; and

[0016] the projections of the first tab and the third tab in the thickness direction of the battery cell are staggered from each other, and the projections of the second tab and the fourth tab in the thickness direction of the battery cell are staggered from each other.

[0017] In some embodiments, the first tab and the second tab are arranged in central symmetry on the positive electrode sheet, and the third tab and the fourth tab are arranged in central symmetry on the negative electrode sheet.

[0018] In some embodiments, in the second direction, the ratio of the distance between the first tab and the third tab to the size of the positive electrode sheet in the second direction is 0.1 - 0.25, and / or the ratio of the distance between the second tab and the fourth tab to the size of the positive electrode sheet in the second direction is 0.1 - 0.25.

[0019] In some embodiments, the sizes of the first tab, the second tab, the third tab, and the fourth tab in the first direction are each independently 30 mm - 100 mm.

[0020] In some embodiments, the ratio of the size of the positive electrode sheet in the first direction to the size of the positive electrode sheet in the second direction is 5 - 18, and the ratio of the size of the negative electrode sheet in the first direction to the size of the negative electrode sheet in the second direction is 4 - 16.

[0021] In some embodiments, the sizes of the separator, the positive electrode sheet, and the negative electrode sheet satisfy the following relationship:

[0022] In the third direction of the battery cell, the projected area of the separator is the first projected area, the projected area of the negative current collector is the second projected area, the projected areas of the first negative paste area and the second negative paste area are the same and are the third projected area, the projected area of the positive current collector is the fourth projected area, the projected area of the positive paste area is the fifth projected area, and the first projected area > the second projected area > the third projected area > the fourth projected area, and the fourth projected area is equal to the fifth projected area; wherein,

[0023] The third direction is perpendicular to the first direction and the second direction.

[0024] In some embodiments, along the first direction, the ratio of the size of the second negative paste area to the size of the positive paste area is 1.002 - 1.01.

[0025] In some embodiments, along the first direction, the ratio of the size of the first negative paste area to the size of the positive paste area is 1.002 - 1.01.

[0026] In some embodiments, along the second direction, the ratio of the size of the first negative paste area to the size of the positive paste area is 1.02 - 1.08.

[0027] In some embodiments, along the second direction, the ratio of the size of the second negative paste area to the size of the positive paste area is 1.02 - 1.08.

[0028] Second, embodiments of the present invention further provide a battery, which includes:

[0029] A battery housing, the battery housing comprising a first side surface and a second side surface arranged opposite to each other;

[0030] The battery cell of any of the above embodiments is arranged in a battery casing;

[0031] A positive electrode column and a negative electrode column, the positive electrode column includes a first positive electrode column and a second positive electrode column, the negative electrode column includes a first negative electrode column and a second negative electrode column, the first positive electrode column and the first negative electrode column are arranged on the first side, and the second positive electrode column and the second negative electrode column are arranged on the second side;

[0032] The first positive electrode column is electrically connected to the first electrode tab, the second positive electrode column is electrically connected to the second electrode tab, the first negative electrode column is electrically connected to the third electrode tab, and the second negative electrode column is electrically connected to the fourth electrode tab.

[0033] The battery cell provided by the utility model, under the premise of maintaining energy density, is provided with a first negative electrode empty foil area around the first negative electrode paste area of ​​the negative electrode sheet. The first negative electrode empty foil area has no paste, has a small impedance, and the current has a tendency to be preferentially conducted to the first negative electrode empty foil area. When charging at a high rate, the current is preferentially conducted to the first negative electrode empty foil area around the first negative electrode paste area, and then conducted from the first negative electrode empty foil area to the inside of the negative electrode sheet. Therefore, the current density around the pole ear of the negative electrode sheet can be effectively reduced, the lithium precipitation problem caused by the polarization of the negative electrode can be alleviated, and the charging rate can be improved, thereby taking into account both high energy density and fast charging performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is a schematic diagram of the structure of the negative electrode sheet disclosed in the embodiment of the utility model.

[0036] Figure 2 It is a schematic diagram of the structure of the positive electrode sheet disclosed in the embodiment of the utility model.

[0037] Figure 3 It is a schematic diagram of the front exploded structure of the battery cell disclosed in the embodiment of the utility model.

[0038] Figure 4 It is a rear exploded structural schematic diagram of a battery cell disclosed in an embodiment of the utility model.

[0039] Figure 5 It is a schematic diagram of the superposed position of the positive electrode sheet and the negative electrode sheet disclosed in the embodiment of the present utility model.

[0040] Figure 6 It is a schematic diagram of the coating effect of the positive electrode strip containing multiple positive electrode sheets disclosed in the embodiment of the present utility model.

[0041] Figure 7 It is a schematic diagram of the cutting trajectory of the coated positive electrode strip cut along the first direction in the embodiment of the present utility model.

[0042] Figure 8 It is a schematic diagram of the cutting trajectory of the positive electrode strip cut along the second direction after being cut along the first direction in the embodiment of the present utility model.

[0043] Figure 9 It is a schematic diagram of the cutting trajectory of the pole ear cut out from the positive electrode film after being cut in the first direction in the embodiment of the present utility model.

[0044] Figure 10 It is a schematic diagram of the coating effect of the negative electrode strip containing multiple negative electrode sheets disclosed in the embodiment of the present utility model.

[0045] Figure 11 It is a schematic diagram of the cutting trajectory of the coated negative electrode strip cut along the first direction in the embodiment of the present utility model.

[0046] Figure 12 It is a schematic diagram of the cutting trajectory of the negative electrode strip cut along the second direction after being cut along the first direction in the embodiment of the present utility model.

[0047] Figure 13 It is a schematic diagram of the cutting trajectory of the pole ear cut out from the negative electrode film after being cut in the first direction in the embodiment of the present utility model.

[0048] Figure 14 It is a schematic diagram of the simulation result of the current density during the charging process in Embodiment 1 of the present utility model.

[0049] Figure 15 It is a schematic diagram of the simulation result of the current density during the charging process in Comparative Example 1 of the present utility model.

[0050] Figure 16 It is a schematic diagram of the simulation result of the current density during the charging process in Comparative Example 2 of the present utility model.

[0051] Figure 17 It is a schematic diagram of the potential contour map during the charging process in Embodiment 1 of the present utility model.

[0052] Figure 18 It is a schematic diagram of the potential contour map during the charging process in Comparative Example 1 of the present utility model.

[0053] Figure 19 It is a schematic diagram of the potential cloud map during the charging process of Comparative Example 2 of the present utility model.

[0054] Description of the reference numerals in the drawings:

[0055] 1. Battery cell; 11. Positive electrode plate; 111. Positive current collector; 112. Positive active material layer; 113. First tab; 114. Second tab; 12. Negative electrode plate; 121. Negative current collector; 122. First negative paste area; 123. Second negative paste area; 124. Third tab; 125. Fourth tab; 126. First negative empty foil area; 126a. First region; 126b. Second region; 126c. Third region; 126d. Fourth region; K1. Width of the first region; K2. Width of the second region; K3. Width of the third region; K4. Width of the fourth region; 127. Second negative empty foil area; 13. Separator. Specific embodiments

[0056] The following further describes the embodiments of the present utility model in detail in conjunction with the drawings and examples. The detailed description and drawings of the following examples are used to exemplarily illustrate the principle of the present utility model, but cannot be used to limit the scope of the present utility model. The present utility model can be implemented in many different forms, not limited to the specific embodiments disclosed in the text, but including all technical solutions falling within the scope of the claims.

[0057] The present utility model provides these embodiments to make the present utility model thorough and complete, and to fully express the scope of the present utility model to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangements of the components and steps, the components of the materials, the numerical expressions and values described in these embodiments should be interpreted as merely exemplary, rather than as a limitation.

[0058] It should be noted that in the description of the present utility model, unless otherwise specified, the meaning of "a plurality" is greater than or equal to two; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present utility model. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0059] In addition, the "first", "second", "third", "fourth" and similar terms used in the present utility model do not denote any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean strictly vertical, but within the allowable error range. "Parallel" does not mean strictly parallel, but within the allowable error range. Words such as "including" or "comprising" mean that the elements before this word cover the elements listed after this word, and do not exclude the possibility of also covering other elements.

[0060] It should also be noted that in the description of the present utility model, unless otherwise clearly defined and limited, the terms "installed", "connected" and "joined" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. When it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0061] All terms used in the present utility model have the same meanings as understood by those of ordinary skill in the art to which the present utility model pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless specifically defined as such here.

[0062] Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods and devices should be regarded as part of the specification.

[0063] Lithium-ion batteries have advantages such as high voltage platforms, high energy densities, and long cycle lives, making them the main energy source in the fields of consumer electronics and electric vehicles. Currently, lithium-ion power batteries are gradually developing towards high safety, long endurance and fast charging.

[0064] Safety performance is the bottom line of a product, and the progress of the industry has also put forward higher requirements for the safety performance of lithium-ion batteries. Many high-energy-density materials such as high-nickel ternary have affected large-scale applications due to problems such as low thermal decomposition temperature and poor safety performance. Long battery life has always been a pain point in the field of lithium-ion power batteries. Currently, the power market has seen long-range batteries with a maximum support of 150 kWh, and the battery life limit can reach 1,200 kilometers. Higher energy density is the common pursuit goal of workers in this field. At the same time, as the shipment volume of China's lithium battery industry moves towards the TWh (hundred million kWh) era, the requirements for fast charging performance have changed from 1C - 2C to 2C - 5C. It is an urgent need for customers in the power battery field to be able to charge 80% of the battery capacity in 10 - 15 minutes.

[0065] The special design of the cell structure can achieve the improvement of specific battery performance and meet the needs of different customers. High energy density is usually achieved through methods such as thick coating, high compaction, and extreme utilization of space, while fast charging performance is achieved through technologies such as STP, multi-tab design, and thin coating. Generally speaking, the designs of high energy density and fast charging performance restrict each other. High-rate charge and discharge will sacrifice the energy density of the battery to a large extent. How to achieve the highest possible fast charging performance while ensuring the energy density has always been an urgent problem to be solved at the forefront of this field.

[0066] To solve the above technical problems, on the one hand, an embodiment of the present utility model provides a cell, including: a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the separator, and the negative electrode sheet are stacked in sequence. The positive electrode sheet includes a positive current collector and a positive active material layer. Along the thickness direction of the cell, on both sides of the positive current collector, there are positive paste application areas, and the positive active material layer covers the positive paste application areas;

[0067] The negative electrode sheet includes a negative current collector and a negative active material layer. Along the thickness direction of the cell, the negative current collector has opposite first and second sides. The first side of the negative current collector includes a first negative empty foil area and a first negative paste application area. The negative active material layer covers the first negative paste application area, and the first negative empty foil area is not coated with the negative active material layer. The first negative empty foil area is arranged around the circumferential side of the first negative paste application area.

[0068] For the cell provided by the present utility model, on the premise of maintaining the energy density, an empty foil area is arranged around the first negative paste application area of the negative electrode sheet. The first negative empty foil area has no paste application and has a relatively small impedance. The current has a tendency to preferentially conduct to the first negative empty foil area. During high-rate charging, the current preferentially conducts to the first negative empty foil area around the first negative paste application area, and then conducts from the first negative empty foil area to the inside of the negative electrode sheet. This can effectively reduce the current density around the tab of the negative electrode sheet, alleviate the problem of lithium deposition caused by negative electrode polarization, achieve an increase in the charging rate, and thus balance high energy density and fast charging performance.

[0069] The battery cell provided in the embodiment of the utility model can be used for a long blade type laminated battery.

[0070] The battery cell 1 provided by the embodiment of the utility model, under the premise of maintaining energy density, is provided with an empty foil area around the first negative electrode paste area 122 of the negative electrode sheet 12, the first negative electrode empty foil area 126 is not coated with paste, the impedance is small, and the current has a tendency to be preferentially conducted to the first negative electrode empty foil area 126. When charging at a high rate, the current is preferentially conducted to the first negative electrode empty foil area 126 around the first negative electrode paste area 122, and then conducted from the first negative electrode empty foil area 126 to the inside of the negative electrode sheet 12. Therefore, the current density around the pole ear of the negative electrode sheet 12 can be effectively reduced, the lithium precipitation problem caused by the polarization of the negative electrode can be alleviated, and the charging rate can be improved, thereby taking into account both high energy density and fast charging performance.

[0071] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the second side of the negative electrode current collector includes a second negative electrode pasted area and a second negative electrode empty foil area, the negative electrode active material coating covers the second negative electrode pasted area, the second negative electrode empty foil area is not coated with the negative electrode active material layer, and the second negative electrode empty foil area is arranged around the second negative electrode pasted area.

[0072] Combine the following Figures 1 to 19 , the battery cell of the utility model is specifically introduced.

[0073] like Figures 1 to 4 As shown, in the first aspect, the embodiment of the utility model provides a battery cell 1, including a positive electrode sheet 11, a negative electrode sheet 12 and a separator 13. The positive electrode sheet 11 includes a positive electrode current collector 111 and a positive electrode active material layer 112. Both sides of the positive electrode current collector 111 ( Figure 3 and Figure 4 The positive electrode current collector 111 has a positive electrode paste coating area on its upper and lower surfaces, and the positive electrode active material layer 112 covers the positive electrode paste coating area. The negative electrode sheet 12 includes a negative electrode current collector 121 and a negative electrode active material layer. The first side ( Figure 3 and Figure 4 The upper surface of the negative electrode current collector 121 includes a first negative electrode empty foil area 126 and a first negative electrode paste area 122. The first negative electrode empty foil area 126 is arranged around the first negative electrode paste area 122. The second side ( Figure 3 and Figure 4 The lower surface of the negative electrode current collector 121 includes a second negative electrode paste area 123. The negative electrode active material layer covers the first negative electrode paste area 122 and the second negative electrode paste area 123. The negative electrode sheets 12 and the positive electrode sheets 11 are alternately stacked in sequence, and the separator 13 is arranged between the positive electrode sheets 11 and the negative electrode sheets 12.

[0074] In some embodiments, an empty foil area is simultaneously provided around the first negative electrode paste area 122 and the second negative electrode paste area 123 of the negative electrode sheet 12. The first negative electrode empty foil area 126 and the second negative electrode empty foil area 127 have no paste, with a relatively small impedance, and the current has a tendency to preferentially conduct to the first negative electrode empty foil area 126 and the second negative electrode empty foil area 127. During high-rate charging, the current preferentially conducts to the first negative electrode empty foil area 126 and the second negative electrode empty foil area 127, and then enters the negative electrode sheet 12 from the first negative electrode empty foil area 126 and the second negative electrode empty foil area 127, which can further effectively reduce the current density around the tab of the negative electrode sheet 12, alleviate the lithium deposition problem caused by negative electrode polarization, achieve an increase in the charging rate, and thus balance high energy density and fast charging performance.

[0075] In some embodiments, the thicknesses of the first negative electrode active material layer and the second negative electrode active material layer are each independently 50 μm - 120 μm, and can be, for example, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, and 120 μm, as well as the ranges formed by any two endpoints.

[0076] In some embodiments, the thickness of the positive electrode active material layer is 80 μm - 170 μm, and can be, for example, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, and 170 μm, as well as the ranges formed by any two endpoints. The thickness of the positive electrode active material layer is the thickness of the positive electrode active material layer provided on one side of the positive electrode current collector.

[0077] In some embodiments, along the first direction ( Figures 1 to 3 the X direction shown in), the ratio of the size of the negative electrode current collector 121 to the first negative electrode paste area 122 is 1.0005 - 1.007, and can be, for example, 1.0005, 1.001, 1.002, 1.003, 1.004, 1.005, 1.006, and 1.007, as well as the ranges formed by any two endpoints. The ratio of the size of the negative electrode current collector 121 to the second negative electrode paste area 123 is 1.0005 - 1.007, and can be, for example, 1.0005, 1.001, 1.002, 1.003, 1.004, 1.005, 1.006, and 1.007, as well as the ranges formed by any two endpoints.

[0078] In some embodiments, along the second direction ( Figures 1 to 3In the Y direction shown in the figure, the ratio of the size of the negative electrode current collector 121 to that of the first negative electrode paste application area 122 is 1.005 - 1.05. For example, it can be 1.005, 1.01, 1.02, 1.03, 1.04, 1.05, and the range formed by any two endpoints. The ratio of the size of the negative electrode current collector 121 to that of the second negative electrode paste application area 123 is 1.005 - 1.05. For example, it can be 1.005, 1.01, 1.02, 1.03, 1.04, 1.05, and the range formed by any two endpoints. Among them, the first direction is perpendicular to the second direction.

[0079] Controlling the size relationship between the paste application area and the negative electrode current collector 121 within the above range can make the current during the charge and discharge process tend to be transmitted to the position with low impedance at the edge, increase the current transmission area, take into account both high energy density and fast charging performance, and better improve the battery performance.

[0080] In some embodiments, the first negative electrode empty foil area 126 or the second negative electrode empty foil area 127 (referred to as the "empty foil area" in this paragraph) is arranged around the circumferential side of the first negative electrode paste application area 122 or the second negative electrode paste application area 123 (referred to as the "paste application area" in this paragraph). Thus, the negative electrode empty foil area includes four slender empty foil areas respectively located on the four sides of the paste application area. In some embodiments, the first negative electrode empty foil area has a first area 126a, a second area 126b, a third area 126c, and a fourth area 126d that are sequentially connected end to end. The first area 126a and the third area 126c are opposite to each other in the second direction and extend in the first direction. The second area 126b and the fourth area 126d are opposite to each other in the first direction and extend in the second direction. Among them, the difference in the width of any two areas is within 10%. Controlling the size relationship between the first negative electrode empty foil area 126 and the second negative electrode empty foil area 127 within this range can maximize the paste application area and the effective area utilization rate of the foil, avoid excessive waste of the foil area, and better balance high energy density and fast charging performance.

[0081] In one implementation manner, the width K1 of the first area, the width K2 of the second area, the width K3 of the third area, and the width K4 of the fourth area are all the same.

[0082] In some embodiments, on each side of the first negative electrode paste application area 122, the width of the first negative electrode empty foil area 126 is the same. On each side of the second negative electrode paste application area 123, the width of the second negative electrode empty foil area 127 is the same. In this way, the manufacture of the empty foil area can be realized during the coating process, which is convenient for processing.

[0083] As Figures 1 to 4As shown, in some embodiments, in the first direction, a first tab 113 is provided at the first end of the positive electrode sheet 11, a second tab 114 is provided at the second end of the positive electrode sheet 11, a third tab 124 is provided at the first end of the negative electrode sheet 12, and a fourth tab 125 is provided at the second end of the negative electrode sheet 12. The first tab 113 and the second tab 114 are electrically connected to the positive current collector 111, and the third tab 124 and the fourth tab 125 are electrically connected to the negative current collector 121. As Figure 5 shown, in some embodiments, the projections of the first tab 113 and the third tab 124 in the thickness direction of the battery cell are staggered from each other, and the projections of the second tab 114 and the fourth tab 125 in the thickness direction of the battery cell are staggered from each other.

[0084] In this way, the number of tabs is doubled, which can further alleviate the problems of large current density and serious polarization and easy lithium deposition at the tabs, realize the improvement of the charging rate, and better balance the high energy density and fast charging performance. In addition, during lamination, the projections of the first tab 113 and the third tab 124 in the thickness direction of the battery cell are staggered from each other, and the projections of the second tab 114 and the fourth tab 125 in the thickness direction of the battery cell are staggered from each other, which is convenient to avoid short circuits caused by the contact of the tabs of the positive electrode sheet 11 and the negative electrode sheet 12.

[0085] It should be noted that the positions of the first tab 113 and the second tab 114, and the positions of the third tab 124 and the fourth tab 125 can be interchanged. In addition, during stacking, the positions of the first tab 113 and the third tab 124, and the positions of the second tab 114 and the fourth tab 125 can be interchanged.

[0086] As Figure 2 shown, in some embodiments, the first tab 113 and the second tab 114 are arranged in central symmetry on the positive electrode sheet 11, and the third tab 124 and the fourth tab 125 are arranged in central symmetry on the negative electrode sheet 12.

[0087] In this way, when assembling the battery, the same top cover can be used on both sides of the battery cell 1, which is convenient for mass production and replacement of the top cover.

[0088] As Figure 5 shown, in some embodiments, in the second direction, the ratio of the distance between the first tab 113 and the third tab 124 to the positive electrode sheet 11 in the second direction is 0.1-0.25, and / or the ratio of the distance between the second tab 114 and the fourth tab 125 to the positive electrode sheet 11 in the second direction is 0.1-0.25. Here, the distance between the first tab 113 and the third tab 124 is the distance between the two closest sides of the first tab 113 and the third tab 124, and the distance between the second tab 114 and the fourth tab 125 is the distance between the two closest sides of the second tab 114 and the fourth tab 125.

[0089] Control the distances between the first tab 113 and the third tab 124, and between the second tab 114 and the fourth tab 125 within this range to ensure the distance between the positive and negative tabs, and avoid short circuits caused by the contact of the tabs of the positive electrode sheet 11 and the negative electrode sheet 12. At the same time, increase the tab width as much as possible to improve the current-carrying capacity and heat dissipation capacity of the tabs, and avoid thermal failure caused by excessive charging and discharging currents.

[0090] In some embodiments, the dimensions of the first tab 113, the second tab 114, the third tab 124, and the fourth tab 125 in the first direction ( Figure 1 and Figure 2 the X direction in

[0091] are each independently 30 mm - 100 mm, and can be, for example, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm.

[0092] In this way, when assembled into a battery, the space utilization rate can be maximized, and the battery can be used in high-voltage energy storage and power fields with high energy density requirements.

[0093] In some embodiments, the dimensions of the separator 13, the positive electrode sheet 11, and the negative electrode sheet 12 satisfy the following relationship:

[0094] In the third direction of the battery cell 1 ( Figure 3 and Figure 4 the Z direction shown in

[0095] the projection area of the separator 13 is the first projection area, the projection area of the negative current collector 121 is the second projection area, the projection areas of the first negative paste area 122 and the second negative paste area 123 are the same and are the third projection area, the projection area of the positive current collector 111 is the fourth projection area, the projection area of the positive paste area is the fifth projection area, the first projection area > the second projection area > the third projection area > the fourth projection area, and the fourth projection area is equal to the fifth projection area. Among them, the third party is perpendicular to the first direction and the second direction.

[0096] In some embodiments, the number of the positive electrode sheets 11 in the battery cell 1 is 60 - 115, and the number of the negative electrode sheets 12 is 61 - 116. It should be noted that those skilled in the art can also adjust the numbers of the negative electrode sheets 12 and the positive electrode sheets 11 according to the needs of specific application scenarios.

[0097] In some embodiments, along the first direction, the ratio of the size of the separator 13 to that of the negative electrode sheet 12 is 1.003 - 1.006, and the ratios of the size of the negative electrode sheet 12 to those of the first negative electrode coating area 122 and the second negative electrode coating area 123 are each independently 1.0005 - 1.007, and the ratio of the size of the positive electrode sheet 11 to that of the positive electrode coating area is 1.

[0098] In some embodiments, along the second direction, the ratio of the size of the separator 13 to that of the negative electrode sheet 12 is 1.01 - 1.03, and the ratios of the size of the negative electrode sheet 12 to those of the first negative electrode coating area 122 and the second negative electrode coating area 123 are each independently 1.005 - 1.05, and the ratio of the size of the positive electrode sheet 11 to that of the positive electrode coating area is 1.

[0099] In some embodiments, along the first direction, the ratio of the size of the first negative electrode coating area 122 to that of the positive electrode coating area is 1.002 - 1.01, and can be, for example, 1.002, 1.003, 1.004, 1.005, 1.006, 1.007, 1.008, 1.009, and 1.01.

[0100] In some embodiments, along the first direction, the ratio of the size of the second negative electrode coating area 123 to that of the positive electrode coating area is 1.002 - 1.01, and can be, for example, 1.002, 1.003, 1.004, 1.005, 1.006, 1.007, 1.008, 1.009, and 1.01.

[0101] In some embodiments, along the second direction, the ratio of the size of the first negative electrode coating area 122 to that of the positive electrode coating area is 1.02 - 1.08, and can be, for example, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, and 1.08.

[0102] In some embodiments, along the second direction, the ratio of the size of the second negative electrode coating area 123 to that of the positive electrode coating area is 1.02 - 1.08, and can be, for example, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, and 1.08.

[0103] In some embodiments, the stacking length of the battery cell 1 is 1000 mm - 3200 mm, the width is 150 mm - 220 mm, the thickness is 40 mm - 72 mm, and the weight is 10 Kg - 54 Kg. In this way, by controlling the above parameters of the battery cell 1, the negative electrode sheet 12, the positive electrode sheet 11, and the separator 13 within the above ranges, the maximum space utilization rate can be ensured when assembling the battery, enabling the battery to be used in high-voltage energy storage and power fields with high energy density requirements.

[0104] It should be noted that those skilled in the art can also adjust the above parameters of the battery cell 1, the negative electrode sheet 12, the positive electrode sheet 11, and the separator 13 according to the needs of specific application scenarios.

[0105] Figures 6 to 9 is the manufacturing process of the positive electrode sheet.

[0106] The specific manufacturing process is as follows: The positive electrode active material slurry is respectively coated on the upper and lower sides of the positive electrode current collector to obtain a positive electrode sheet strip containing multiple positive electrode sheets with a coated paste area, and the coating track is as Figure 6 shown.

[0107] Then, the obtained positive electrode sheet strip is divided along the first direction (in one example, the division track coincides with the edge of the paste area, as Figure 7 shown; in another example, the division track is inside the paste area and parallel to the edge of the paste area), so that the positive electrode sheet strip is slit in the second direction to obtain a positive electrode sheet strip without an empty foil area in the second direction.

[0108] Then, the obtained positive electrode sheet strip without an empty foil area in the second direction is slit along the second direction (in one example, the slitting track is parallel to the edge of the paste area, and the division track is as Figure 8 shown), so that the positive electrode sheet strip is slit in the first direction into positive electrode sheets with appropriate lengths, and empty foil areas with a certain length are reserved at both ends of the positive electrode sheets in the first direction for setting the tabs.

[0109] Then, tabs are formed by laser or cutter cutting on the empty foil areas with a certain length reserved at both ends of the positive electrode sheet. The upper right end and the lower left end of the positive electrode sheet are the tab positions of the positive electrode, as Figure 9 shown.

[0110] Figures 10 to 13 is the manufacturing process of the negative electrode sheet.

[0111] The specific manufacturing process is as follows: The negative electrode active material slurry is respectively coated on the upper and lower sides of the negative electrode current collector to obtain a negative electrode sheet strip containing multiple negative electrode sheets with a coated paste area, and the coating track is as Figure 10 shown.

[0112] Then, the obtained negative electrode strip is divided along the first direction (in one example, the dividing trajectory is parallel to the edge of the coating area, as Figure 11 shown), so that the negative electrode strip is slit in the second direction, and a negative electrode strip with empty foil areas of a certain width reserved on both sides of the negative electrode coating area is obtained.

[0113] Then, the negative electrode strip with empty foil areas in the second direction obtained above is slit along the second direction (in one example, the slitting trajectory is parallel to the edge of the coating area, and the dividing trajectory is as Figure 12 shown), so that the negative electrode strip is slit in the first direction into negative electrode sheets with appropriate lengths, and empty foil areas are reserved at both ends of the negative electrode coating area in addition to the negative electrode coating area of the negative electrode sheet, and empty foil areas of a certain length are reserved at both ends of the negative electrode sheet in the first direction for arranging pole ears.

[0114] Then, pole ears are formed by laser or cutter cutting on the empty foil areas of a certain length reserved at both ends of the negative electrode sheet. The lower right end and the upper left end of the negative electrode sheet are the positions of the negative electrode pole ears, as Figure 13 shown.

[0115] In the present utility model, the material of the negative electrode active material layer is not specifically limited as long as it can meet the actual requirements.

[0116] In some embodiments, the negative electrode active material layer includes a negative electrode active material, a first adhesive, and a first conductive agent.

[0117] In the present utility model, the material of the positive electrode active material layer is not specifically limited as long as it can meet the actual requirements.

[0118] In some embodiments, the positive electrode active material layer includes a positive electrode active material, a second adhesive, and a second conductive agent.

[0119] In some embodiments, the negative electrode active material is one or a combination of at least two materials selected from graphite, carbon microspheres, graphene, carbon silicon, carbon oxygen, nitrides, and lithium titanate.

[0120] In some embodiments, the positive electrode active material is one or a combination of at least two materials selected from lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxide phosphate, lithium-rich manganese-based materials, and lithium nickel cobalt aluminate.

[0121] In some embodiments, the first conductive agent and the second conductive agent are each independently one or a combination of at least two materials selected from carbon black, super P (SP), carbon fiber, carbon nanotube (CNT), graphite, graphene, metal powder, composite conductive material, and conductive ceramic powder.

[0122] In some embodiments, the first adhesive and the second adhesive are each independently one or a combination of at least two materials selected from polyvinylidene fluoride (PVDF), copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate salt, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyethylene ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, and styrene-butadiene rubber (SBR).

[0123] In a second aspect, an embodiment of the present invention further provides a battery, which includes a battery housing, the battery cell 1 described in any of the above embodiments, a positive electrode terminal, and a negative electrode terminal. Among them, the battery cell 1 is disposed inside the battery housing. The positive electrode terminal includes a first positive electrode terminal and a second positive electrode terminal, the negative electrode terminal includes a first negative electrode terminal and a second negative electrode terminal, the battery housing includes a first side surface and a second side surface disposed opposite to each other, the first side surface is provided with the first positive electrode terminal and the first negative electrode terminal, and the second side surface is provided with the second positive electrode terminal and the second negative electrode terminal. Among them, the first positive electrode terminal is electrically connected to the first tab 113, the second positive electrode terminal is electrically connected to the second tab 114, the first negative electrode terminal is electrically connected to the third tab 124, and the second negative electrode terminal is electrically connected to the fourth tab 125.

[0124] In this way, there are both positive and negative terminals on both sides of the battery, effectively increasing the heat dissipation area, and further improving the level of battery performance, which can solve problems such as large heat generation and difficult heat dissipation of the long knife-shaped battery cell 1.

[0125] Next, in order to more deeply understand and illustrate the battery cell of the present invention, some embodiments of the preparation of the battery cell are provided. All lengths in the following embodiments and comparative examples refer to the length in the first direction ( Figures 1 to 3 the X direction shown in Figures 1 to 3 ), the width refers to the length in the second direction ( Figure 3 the Y direction shown in Figure 4 ), and the thickness refers to the length in the third direction ( Figure 3 and Figure 4 the Z direction shown in

[0126] Example 1

[0127] The battery cell is prepared through the following steps.

[0128] Preparation of the negative electrode paste: Mix the negative electrode active material graphite, the conductive agent super P and carbon nanotubes, the dispersant sodium carboxymethyl cellulose (CMC-Na), the first adhesive styrene-butadiene rubber, and the solvent water to obtain the negative electrode paste. The mass ratio of the negative electrode active material: CMC-Na: SBR: SP: CNT is 96: 1.5: 1.5: 0.9: 0.1.

[0129] Preparation of the positive electrode paste: The positive electrode active material lithium nickel cobalt manganate with a residual alkali content ≤ 1000 ppm, the second adhesive PVDF, the solvent N-methylpyrrolidone (NMP), the conductive agent SP, and CNT are mixed to obtain a mixed paste. The mass ratio of lithium nickel cobalt manganate, PVDF, SP, and CNT is 96:2:1.5:0.5.

[0130] The above negative electrode paste is coated on both the upper and lower sides of the negative electrode current collector using a wide-width coater. The coating is carried out in an intermittent coating manner. The negative electrode coating width is 206 mm, and a 200-mm empty foil area is reserved every 3010 mm of coating. The single-side coating thickness of the negative electrode active material layer is 69 μm.

[0131] The positive electrode paste is coated on both the upper and lower sides of the positive electrode current collector. The coating is carried out in an intermittent coating manner. The positive electrode tab coating width is 200 mm, and a 200-mm empty foil area is reserved every 3000 mm of coating. The single-side coating thickness of the positive electrode active material layer is 99 μm.

[0132] Pole piece slitting:

[0133] After conventional rolling, the pole piece is slit to a suitable width. The positive electrode piece is slit in the middle into positive electrode strips with a width of 200 mm and no empty foil area in the second direction.

[0134] After width slitting, the pole piece is slit from the middle line position of the empty foil area to a suitable length. The length × width of the positive electrode piece is 3000 mm × 200 mm, where the length × width of the positive electrode paste area is 3000 mm × 200 mm.

[0135] The length × width of the negative electrode piece is 3016 mm × 212 mm, where the length × width of the negative electrode paste area is 3010 mm × 206 mm. The width of any one of the negative electrode empty foil areas around the negative electrode paste area is 3 mm.

[0136] Pole piece die-cutting:

[0137] The slit pole piece is cut by laser or cutter to form tabs at the positions reserved for tabs on both sides in the length direction. Taking the feeding direction of the coating surface as the right, the upper right and lower left of the positive electrode piece are the positive electrode tab positions. The positive electrode tab width is 80 mm and the length is 80 mm. The lower right and upper left of the negative electrode piece are the negative electrode tab positions. The negative electrode tab width is 80 mm and the length is 80 mm. Among them, there is an empty foil area with a width of 3 mm between both sides of the negative electrode tabs and the paste area. The cut pole piece is collected by a magazine and transported to the lamination process for use.

[0138] The separator is a polyethylene separator. The length of the separator is 3030 mm, and the width of the separator is 216 mm.

[0139] Preparation of electrolyte: In a glove box under an argon atmosphere with a water content of < 10 ppm, ethylene carbonate (EC), diethyl carbonate (DEC), and propylene carbonate (PC) were mixed evenly according to a mass ratio of 25:70:5 to obtain an organic solvent. Then, a lithium salt of 12.5 wt% lithium hexafluorophosphate and an additive were added to the organic solvent.

[0140] Through conventional processes such as stacking, assembling, vacuum baking, liquid injection, standing, encapsulation, formation, and grading, the above materials were used to prepare a lithium-ion battery. The distance between the first tab and the third tab is 35 mm, and the distance between the second tab and the fourth tab is 35 mm.

[0141] Example 2

[0142] Different from Example 1, the length × width of the positive electrode sheet is 2500 mm × 200 mm, where the length × width of the positive electrode paste area is 2500 mm × 200 mm; the length × width of the negative electrode sheet is 2516 mm × 212 mm, where the length × width of the negative electrode paste area is 2510 mm × 206 mm.

[0143] Example 3

[0144] Different from Example 1, the length × width of the positive electrode sheet is 1500 mm × 200 mm, where the length × width of the positive electrode paste area is 1500 mm × 200 mm; the length × width of the negative electrode sheet is 1516 mm × 212 mm, where the length × width of the negative electrode paste area is 1510 mm × 206 mm.

[0145] Example 4

[0146] Different from Example 1, the length × width of the positive electrode sheet is 1000 mm × 200 mm, where the length × width of the positive electrode paste area is 1000 mm × 200 mm; the length × width of the negative electrode sheet is 1016 mm × 212 mm, where the length × width of the negative electrode paste area is 1010 mm × 206 mm.

[0147] Example 5

[0148] Different from Example 1, the length × width of the negative electrode sheet is 3012 mm × 208 mm, the width of any negative electrode empty foil area is 1 mm, and the length and width of the negative electrode paste area remain unchanged.

[0149] Example 6

[0150] Different from Example 1, the length × width of the negative electrode sheet is 3014 mm × 210 mm, the width of any negative electrode empty foil area is 2 mm, and the length and width of the negative electrode paste area remain unchanged.

[0151] Example 7

[0152] Different from Example 1, the length × width of the negative electrode sheet (excluding the tab) is 3020 mm × 216 mm, the width of any negative electrode empty foil area is 5 mm, and the length and width of the negative electrode paste area remain unchanged.

[0153] Example 8

[0154] Different from Example 1, the upper right and upper left of the positive electrode sheet are the positions of the positive electrode tabs, and the lower right and lower left of the negative electrode sheet are the positions of the negative electrode tabs.

[0155] Comparative Example 1

[0156] Different from Example 1, the negative electrode sheet has no empty foil area, and other conditions are the same as those in Example 1.

[0157] Comparative Example 2

[0158] Different from Example 1, the positive and negative electrode tabs of the battery cell are located on both sides of the battery cell respectively, that is, the B-type tab design.

[0159] Perform battery cell charging temperature test and charging rate test on the battery cells prepared in the above examples and comparative examples and the lithium-ion batteries containing the battery cells.

[0160] The test conditions for the battery cell charging temperature test are as follows:

[0161] Temperature at test point 1 / 2 (°C): At room temperature, discharge the battery to 2.5 / 3.0 V at 1C, charge it to full capacity at a constant current of 1C, with a cut-off voltage of 3.65 V / 4.28 V. Place two temperature probes at the positive and negative electrode posts of the battery cell respectively. The average temperature of the positive electrode post is recorded as Temperature 1, and the average temperature of the negative electrode post is recorded as Temperature 2. Read the cut-off temperature at each temperature point during the charging process.

[0162] The test conditions for the charging rate test are as follows:

[0163] 1C charging constant current charging ratio: At room temperature, discharge the battery to 2.5 / 3.0 V at 1C, charge it to full capacity with a constant current and constant voltage at 1C. The cut-off current for constant voltage charging is 0.025C. The charging capacity during the constant current stage is recorded as Cc, and the total charging capacity is recorded as C. Calculate the constant current charging ratio under the charging rate, and the constant current charging ratio is the constant current charging capacity Cc / total charging capacity C.

[0164] Table 1

[0165]

[0166] Table 2

[0167]

[0168]

[0169] In Comparative Example 2, the positive tab and the negative tab of the battery cell are located on both sides of the battery cell respectively, that is, in the B-type tab design, the polarization is serious during the charging process of the battery. The cut-off voltage is reached after charging for 300 s. Continuing to charge will cause overcharging and pose a safety hazard. At this time, the temperatures of Test Points 1 / 2 are too low to be of reference value.

[0170] The battery cells prepared in Example 1, Comparative Example 1 and Comparative Example 2 were respectively subjected to charge and discharge simulation tests to simulate the current density and potential distribution of the electrode sheets during the process of charging at 1C to the cut-off voltage of 3.8V under room temperature conditions. Among them, the simulation results of the current density during the charging process are as Figures 14 to 16 shown, and the simulation results of the potential distribution are as Figures 17 to 19 shown.

[0171] It can be seen from Figures 14 to 16 that for the electrode sheets with different structures, the current density shows a distribution trend that the current density is the largest at the tab and the smallest at the center of the electrode sheet. Among them, Figure 14 is a schematic diagram of the simulation result of the current density during the charging process of Example 1. The current density distribution of Example 1 is the most uniform, and the relative current density difference is 0.79 A / m 2 . Figure 15 is a schematic diagram of the simulation result of the current density during the charging process of Comparative Example 1. The current density distribution of Comparative Example 1 is not uniform, and the relative current density is 0.81 A / m 2 . Figure 16 is a schematic diagram of the simulation result of the current density during the charging process of Comparative Example 2. The uniformity of the current density distribution of Comparative Example 2 is the worst, and the relative current density is 1.46 A / m 2 . Here, the relative current density difference is the difference between the maximum current density and the minimum current density. The smaller the relative current density difference, the less likely lithium plating is to occur.

[0172] Therefore, setting an empty foil area structure around the second active material of the negative electrode sheet has a certain improvement effect on the uniformity of the current density distribution. Compared with the conventional B-type tab structure, the improvement effect on the uniformity of the current density distribution is significant.

[0173] The potential difference reflects the uniformity of the potential distribution of the electrode sheet. As Figures 17 to 19 shown, for the negative electrode sheets with different structures, the potential differences all show a distribution trend that the potential difference is the largest at the tab and the smallest far away from the tab. Among them, the potential distribution of the negative electrode sheet prepared in Example 1 is the most uniform, and the potential difference is 80 mV. The potential distribution of the negative electrode sheet prepared in Comparative Example 1 is relatively poor, and the potential difference is 90 mV. The potential distribution of the negative electrode sheet prepared in Comparative Example 3 is the worst, and the potential difference is 380 mV.

[0174] Therefore, setting an empty foil area structure around the second active material of the negative electrode sheet can improve the uniformity of potential distribution to a certain extent, and the improvement effect is significant compared with the conventional type B electrode sheet structure.

[0175] The charge and discharge simulation results of the electrode sheet show that in the electrode sheet structure with a large aspect ratio, the current density and potential distribution of the conventional type B electrode sheet design are extremely uneven, resulting in a great risk of lithium plating and capacity waste. The tabs are provided at both the first end and the second end of the electrode sheet, effectively solving the problem of uneven current density and potential distribution. The empty foil area design further improves the uniformity of current density and potential distribution during charging. This design provides a new solution for the application of the electrode core with the extreme aspect ratio.

[0176] So far, the embodiments of the present invention have been described in detail. To avoid obscuring the concept of the present invention, some details well known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed here based on the above description.

[0177] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be equivalently replaced without departing from the scope and spirit of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way.

Claims

1. A battery cell, comprising: A positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence, characterized in that: The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer. Along the thickness direction of the battery cell, positive electrode paste areas are arranged on opposite sides of the positive electrode current collector, and the positive electrode active material layer covers the positive electrode paste areas. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. Along the thickness direction of the battery cell, the negative electrode current collector has a first side and a second side opposite to each other. The first side of the negative electrode current collector includes a first negative electrode empty foil area and a first negative electrode pasted area. The negative electrode active material layer covers the first negative electrode pasted area. The first negative electrode empty foil area is not coated with the negative electrode active material layer. The first negative electrode empty foil area is arranged around the circumference of the first negative electrode pasted area.

2. The battery cell according to claim 1, characterized in that: The second side of the negative electrode current collector includes a second negative electrode pasted area and a second negative electrode empty foil area, the negative electrode active material coating covers the second negative electrode pasted area, the second negative electrode empty foil area is not coated with the negative electrode active material layer, and the second negative electrode empty foil area is arranged around the second negative electrode pasted area.

3. The battery cell according to claim 2, characterized in that: Along the first direction, the ratio of the size of the negative electrode current collector to the size of the first negative electrode paste coating area is 1.0005-1.007, and the ratio of the size of the negative electrode current collector to the size of the second negative electrode paste coating area is 1.0005-1.007; And / or, along the second direction, the ratio of the size of the negative electrode current collector to the first negative electrode pasted area is 1.005-1.05, and the ratio of the size of the negative electrode current collector to the second negative electrode pasted area is 1.005-1.05; wherein the first direction is perpendicular to the second direction.

4. The battery cell according to claim 2, characterized in that: The first negative electrode empty foil area has a first region, a second region, a third region, and a fourth region connected end to end in sequence, the first region and the third region are opposite to each other along the second direction and extend along the first direction, the second region and the fourth region are opposite to each other along the first direction and extend along the second direction, wherein, The difference between the widths of any two regions is within 10%.

5. The battery cell according to any one of claims 1 to 4, characterized in that: In the first direction, the first end of the positive electrode sheet is provided with a first pole lug, the second end of the positive electrode sheet is provided with a second pole lug, the first end of the negative electrode sheet is provided with a third pole lug, and the second end of the negative electrode sheet is provided with a fourth pole lug; in The first electrode tab and the second electrode tab are electrically connected to the positive electrode current collector, and the third electrode tab and the fourth electrode tab are electrically connected to the negative electrode current collector; as well as The projections of the first pole tab and the third pole tab in the thickness direction of the battery cell are staggered with each other, and the projections of the second pole tab and the fourth pole tab in the thickness direction of the battery cell are staggered with each other.

6. The battery cell according to claim 5, characterized in that: The first pole tab and the second pole tab are centrally symmetrically arranged on the positive electrode sheet, and the third pole tab and the fourth pole tab are centrally symmetrically arranged on the negative electrode sheet.

7. The battery cell according to claim 5, characterized in that: In the second direction, the ratio of the spacing between the first pole tab and the third pole tab to the size of the positive electrode sheet in the second direction is 0.1-0.25, and / or the ratio of the spacing between the second pole tab and the fourth pole tab to the size of the positive electrode sheet in the second direction is 0.1-0.25; and / or The dimensions of the first pole tab, the second pole tab, the third pole tab and the fourth pole tab in the first direction are independently 30 mm to 100 mm.

8. The battery cell according to claim 3, characterized in that: The ratio of the size of the positive electrode sheet in the first direction to the size of the positive electrode sheet in the second direction is 5-18, and the ratio of the size of the negative electrode sheet in the first direction to the size of the negative electrode sheet in the second direction is 4-16; and / or The dimensions of the separator, the positive electrode sheet, and the negative electrode sheet satisfy the following relationship: In the third direction of the battery cell, the projection area of ​​the diaphragm is the first projection area, the projection area of ​​the negative electrode current collector is the second projection area, the projection areas of the first negative electrode paste area and the second negative electrode paste area are the same and are the third projection area, the projection area of ​​the positive electrode current collector is the fourth projection area, the projection area of ​​the positive electrode paste area is the fifth projection area, the first projection area>the second projection area>the third projection area>the fourth projection area, and the fourth projection area is equal to the fifth projection area; wherein, The third party is perpendicular to the first direction and the second direction.

9. The battery cell according to any one of claims 2 to 4, characterized in that: Along the first direction, the ratio of the size of the second negative electrode paste coating area to the size of the positive electrode paste coating area is 1.002-1.01; and / or Along the first direction, the ratio of the size of the first negative electrode paste coating area to the size of the positive electrode paste coating area is 1.002-1.01; and / or Along the second direction, the ratio of the size of the first negative electrode paste coating area to the size of the positive electrode paste coating area is 1.02-1.08; and / or Along the second direction, the ratio of the size of the second negative electrode paste coating area to the size of the positive electrode paste coating area is 1.02-1.

08.

10. A battery comprising: A battery housing, the battery housing comprising a first side surface and a second side surface arranged opposite to each other; The battery cell according to any one of claims 1 to 9, wherein the battery cell is arranged in the battery casing; A positive electrode column and a negative electrode column, wherein the positive electrode column includes a first positive electrode column and a second positive electrode column, and the negative electrode column includes a first negative electrode column and a second negative electrode column, the first positive electrode column and the first negative electrode column are arranged on the first side, and the second positive electrode column and the second negative electrode column are arranged on the second side; wherein The first positive electrode column is electrically connected to the first electrode tab, the second positive electrode column is electrically connected to the second electrode tab, the first negative electrode column is electrically connected to the third electrode tab, and the second negative electrode column is electrically connected to the fourth electrode tab.

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