Battery

Abstract

The present invention relates to the technical field of batteries, and discloses a battery, which comprises: a laminated cell, which comprises a plurality of pole pieces stacked layer by layer along a first direction, each pole piece comprises a pole piece body and a pole lug, the pole lug is led out from the pole piece body along a second direction, the size of the pole piece body in a third direction is L1 mm, and the size of the pole piece body in a fourth direction is L1 mm; the size of the tab in the third direction is L2 mm, and L1-L2 is more than or equal to 20 and less than or equal to 120; wherein the first direction, the second direction and the third direction are intersected pairwise. According to the invention, the size range of the cut part is limited, so that the overcurrent requirement of the tab is met, the adsorption or clamping stability of the cutting operation can be ensured, the positioning precision of the cutting operation is high, the yield of the tab is improved, and the overall yield of the laminated battery is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a battery. Background Art

[0002] In the production and manufacturing process of laminated batteries, it is necessary to cut the tab area on the electrode sheet to form tabs. However, in the prior art, the positioning accuracy of the cutting operation is poor, resulting in a low yield of tabs, which affects the overall yield of the laminated battery. Summary of the Invention

[0003] The object of the present invention is to provide a battery that can improve the positioning accuracy of the cutting operation and the yield of tabs.

[0004] To achieve the above object, one aspect of the present invention provides a battery, characterized by comprising:

[0005] A laminated battery cell, which includes a plurality of electrode sheets stacked layer by layer along a first direction, the electrode sheet includes an electrode sheet body and a tab, the tab extends from the electrode sheet body along a second direction, the size of the electrode sheet body in a third direction is L1 mm, and the size of the tab in the third direction is L2 mm, satisfying: 20 ≤ L 1 – L 2 ≤ 120;

[0006] Wherein, the first direction, the second direction, and the third direction are perpendicular to each other pairwise.

[0007] Compared with the prior art, the beneficial effect of the above technical solution is as follows:

[0008] The battery of one aspect of the present invention includes a laminated battery cell, and the laminated battery cell includes a plurality of electrode sheets. Each electrode sheet includes an electrode sheet body and a tab. By restricting the dimensional difference between the size L 1 mm of the electrode sheet body in the third direction and the size L 2 mm of the tab in the third direction, while meeting the over-current requirement of the tab, it can also ensure the stability of adsorption or clamping during the cutting operation, improve the positioning accuracy of the cutting operation, improve the yield of the tab, and further improve the overall yield of the laminated battery. Brief Description of the Drawings

[0009] Figure 1 It is a schematic structural diagram of a laminated battery cell according to an embodiment of the present invention.

[0010] Figure 2 It is a schematic structural diagram of a negative electrode sheet according to an embodiment of the present invention.

[0011] Figure 3 It is Figure 2 An enlarged schematic diagram of part B in

[0012] Figure 4 It is a schematic structural diagram of the positive electrode sheet in an embodiment of the present invention.

[0013] Figure 5 is Figure 4 an enlarged schematic diagram of the position C in

[0014] Figure 6 is Figure 4 an enlarged schematic diagram of another embodiment of the position C in

[0015] Figure 7 It is a schematic diagram of the electrode sheet and the reinforcing rib in an embodiment of the present invention.

[0016] Figure 8 is Figure 7 a schematic diagram of another angle of the reinforcing rib in

[0017] Figure 9 It is a schematic structural diagram of the battery in an embodiment of the present invention.

[0018] In the figure, 1. stacked cell; 2. housing; 3. cover plate;

[0019] 11. electrode sheet; 11a. positive electrode sheet; 11b. negative electrode sheet; 111. electrode sheet body; 112. tab; 1121. reinforcing rib; Z. first direction; X. second direction; Y. third direction. Specific Embodiments

[0020] The following combines the accompanying drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0021] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention 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 invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0024] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Please refer to Figure 1 , a battery according to an embodiment of the present invention includes a stacked cell 1. The stacked cell 1 includes a plurality of electrode sheets 11 stacked layer by layer in a first direction Z. Each electrode sheet 11 includes an electrode sheet body 111 and an electrode tab 112. The electrode tab 112 extends from a second direction X, and the size of the electrode sheet body 111 in a third direction Y is L 1 mm, and the size of the electrode tab 112 in the third direction Y is L 2 mm, satisfying: 20 ≤ L 1 – L 2 ≤ 120.

[0026] Wherein, the first direction Z, the second direction X, and the third direction Y intersect pairwise.

[0027] In this embodiment, the height direction of the stacked cell 1 is the first direction Z, the length direction of the stacked cell 1 is the second direction X, and the width direction of the stacked cell 1 is the third direction Y. "Perpendicular" refers to a state where the angle is 85° to 95°.

[0028] The way that the positive electrode sheets 11a and the negative electrode sheets 11b are stacked layer by layer is stacking. The electrode sheets 11 of the same polarity are not continuous, and a separator is disposed between the positive electrode sheets 11a and the negative electrode sheets 11b for separation to form the stacked cell 1.

[0029] The stacked cell 1 has the characteristics of low internal resistance, good heat dissipation performance, uniform mechanical stress distribution, and high energy density. Compared with a wound cell, the stacked cell 1 has a higher utilization rate of the internal space of the battery, and the risk of lithium plating on the battery electrode sheet 11 is relatively small.

[0030] That is, the positive electrode sheet 11a and the negative electrode sheet 11b are two types of electrode sheets 11 with opposite polarities, and the battery cell operates by the movement of metal ions between the positive electrode sheet 11a and the negative electrode sheet 11b. The cycling process of the battery cell is the process in which metal ions move from the positive electrode sheet 11a to the negative electrode sheet 11b and then from the negative electrode sheet 11b to the positive electrode sheet 11a.

[0031] The separator acts as an insulating layer to prevent internal short circuits in the battery caused by the contact between the positive electrode sheet 11a and the negative electrode sheet 11b, and as a semi-permeable layer to prevent the passage of larger molecules while allowing the passage of small-volume charged ions.

[0032] The tab 112 is electrically connected to the electrode sheet 11. Among them, the positive tab 112 is electrically connected to the positive electrode sheet 11a, and the negative tab 112 is electrically connected to the negative electrode sheet 11b. The battery cell realizes charge and discharge through the positive tab 112 and the negative tab 112. The electrode sheet 11 includes a current collector and an active material layer, and the active material layer is coated on the surface of the current collector. When the electrode sheet 11 is the positive electrode sheet 11a, the material of the current collector can be aluminum, and the material of the active material layer can be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, etc. When the electrode sheet 11 is the negative electrode sheet 11b, the material of the current collector can be copper, and the material of the active material layer can be carbon or silicon, etc.

[0033] In this embodiment, the stacked battery cell 1 includes a plurality of electrode sheets 11, and the term "a plurality" means not less than one.

[0034] Since in the cutting process, it is necessary to first position the cutting area, such as adsorbing or clamping the part to be cut off, so as to fix the cutting area, and after cutting the tab 112 with a cutter, the separation of the cut part and the tab 112 area is realized.

[0035] When 20 ≤ L 1 – L 2 ≤ 120, it can meet the over-current requirement of the tab 112 while providing space for the positioning of the cutting area, ensuring the stability of the adsorption or clamping during the cutting operation, improving the positioning accuracy of the cutting operation, improving the yield of the tab 112, and thus improving the overall yield of the stacked battery. L 1 – L 2 If the value is too small, it will result in insufficient adsorption force or clamping force, making it difficult to position the cutting area, affecting the positioning and cutting accuracy of the tab 112, resulting in a decrease in the cutting yield of the tab 112, adhesion between the cut-off electrode sheet 11 and the tab 112 area, or more burrs during cutting, tearing of the tab 112, uneven cutting dimensions of the tab 112, etc.; L 1 – L 2If the value is too large, the size of the tab 112 after cutting will be small, unable to meet the current-carrying requirement of the tab 112. When the battery is fast-charged at a high rate, the tab 112 generates a large amount of heat, the internal resistance of the battery is too large, and the battery has safety risks such as thermal control, and at the same time, it affects the overall charge-discharge rate of the battery.

[0036] Preferably, L 1 –L 2 can take values such as 20, 35, 50, 66, 84, 100, 113, 120.

[0037] When measuring the dimension L 1 and L 2 , a common length measuring tool can be used, such as a ruler or a tape measure.

[0038] Specifically, when measuring L 1 , taking one edge of the electrode tab body 111 in the third direction Y as the reference edge, measure the distance between the reference edge and the other edge along the third direction Y with a length measuring tool, measure multiple times and take the average value to obtain the dimension L 1 mm of the electrode tab body 111 in the third direction Y.

[0039] When measuring L 2 , taking one edge of the tab 112 in the third direction Y as the reference edge, measure the distance between the reference edge and the other edge along the third direction Y with a length measuring tool, measure multiple times and take the average value to obtain the dimension L 2 mm of the tab 112 in the third direction Y.

[0040] In some embodiments, the dimension of the tab 112 in the first direction Z is H mm, and the hardness of the tab 112 is A HRB, satisfying: 0.0003 ≤ (H * A) / (L 1 –L 2 ) ≤ 0.08.

[0041] When this range is satisfied, the current-carrying requirement of the tab 112 can be met on the premise of ensuring the adsorption force or clamping force of the cutting operation. The dimension of the tab 112 in the first direction Z, that is, the thickness of the tab 112, and the hardness of the tab 112 will have higher requirements for the adsorption force or clamping force.

[0042] In addition to controlling the dimension of L 1 –L 2 within the range of 20 mm - 120 mm, the thickness and hardness of the tab 112 simultaneously affect the overall current-carrying capacity of the tab 112 and the yield of the tab 112 cutting. Therefore, when meeting the current-carrying requirement, the thickness, hardness of the tab 112 and L 1 –L 2Ensure the cutting efficiency of the battery tab 112, and avoid the adhesion between the cut tab 11 and the tab 112 area, or the phenomena such as more burrs during cutting, tearing of the tab 112, and uneven cutting size of the tab 112.

[0043] (H*A) / (L 1 –L 2 ) If the value is too small, the current-carrying capacity of the tab 112 cannot be guaranteed, and the tab 112 is prone to folding, resulting in easy formation of virtual soldering when the tab 112 is welded to the pole column, affecting the welding quality, and further affecting the current-carrying capacity between the tab 112 and the pole column; (H*A) / (L 1 –L 2 ) If the value is too large, it will lead to insufficient adsorption force or clamping force during the positioning of the cutting operation, insufficient area for adsorbing the tab 112, unstable support for the tab 112, adhesion during the cutting of the tab 112, or problems such as more burrs during cutting, tearing of the tab 112, and uneven cutting size of the tab 112. Moreover, the tab 112 formed by cutting occupies a large space, affecting the space utilization rate of the battery, and further resulting in low energy density and difficulty in bending the tab 112 subsequently.

[0044] Preferably, (H*A) / (L 1 –L 2 ) can take values such as 0.0003, 0.1, 0.24, 0.36, 0.49, 0.75, 0.08, etc.

[0045] When measuring the dimension H, a common length measuring tool can be used, such as a ruler or a tape measure.

[0046] When measuring H, take one end face of the tab 112 in the first direction Z as the reference plane, and measure the distance between the reference plane and the other end face along the first direction Z through the length measuring tool. Measure multiple times and take the average value to obtain the dimension H mm of the tab 112 in the first direction Z.

[0047] When measuring A, the method of measuring hardness in the national standard can be used for measurement.

[0048] To support the rationality of the above numerical range, this embodiment also conducts tests on the cutting yield and current-carrying capacity of the battery that meets the above numerical range.

[0049] Cutting yield test method: Take 100 pole pieces, use a 300W air-cooled infrared nanosecond laser of the i pg brand as the ear cutting equipment, perform the ear cutting process on each pole piece, and after the ear cutting of each pole piece is completed, measure the maximum size X of burrs or metal chips on the cutting edge of the ear. Count the number N of pole pieces with X ≤ 20μm among the 100 pole pieces. If N ≥ 90, it is determined that the cutting yield is good; if 80 ≤ N < 90, it is determined that the cutting yield is qualified; if N < 80, it is determined that the cutting yield is unqualified.

[0050] Overcurrent capacity test method: At 25°C, test the lithium-ion batteries prepared in the examples and comparative examples according to the following procedure.

[0051] For lithium iron phosphate batteries:

[0052] 1) Connect the pole column to the temperature sensor, charge at a constant current of 4C until 3.65V, and then charge at a constant voltage until the current drops to 0.05C, and record the temperature in the pole column area during the charging process.

[0053] 2) Obtain the highest temperature T in the pole column area during the charging process. When the highest temperature T in the pole column area ≤ 45°C, it is good; when 45°C < T ≤ 65°C, it is qualified; when T > 65°C, it is unqualified.

[0054] For other batteries such as ternary batteries other than lithium iron phosphate batteries:

[0055] 1) Connect the pole column to the temperature sensor, charge at a constant current of 4C until 4.25V, and then charge at a constant voltage until the current drops to 0.05C, and record the temperature in the pole column area during the charging process.

[0056] 2) Obtain the highest temperature T in the pole column area during the charging process. When the highest temperature T in the pole column area ≤ 45°C, it is good; when 45°C < T ≤ 65°C, it is qualified; when T > 65°C, it is unqualified.

[0057] Please refer to Table 1 for the test parameters and index data of each group.

[0058] Table 1

[0059]

[0060]

[0061] As can be seen from the data in Table 1, for those that all meet L 1 –L 2 and (H*A) / (L 1 –L 2 ) numerical range and L 1 、L 2, batteries within the numerical ranges of H and A, that is, Examples 1-6, the tab 112 has good overcurrent capacity, and also has high cutting precision and good cutting yield of the tab 112, thereby improving the overall yield of the laminated battery. For those that all meet L 1 –L 2 and (H*A) / (L 1 –L 2 ) numerical ranges of batteries, but in the case where H is too small and A is too large, that is, Examples 7-8, the overcurrent capacity and cutting yield are both qualified test results. For those that do not meet the L 1 –L 2 numerical range of batteries, that is, Comparative Examples 1-4, at least one of the overcurrent capacity and cutting yield cannot obtain qualified test results.

[0062] In some embodiments, the thickness H mm of the tab 112 and the hardness A HRB of the tab 112 further satisfy: 0.021 ≤ H*A ≤ 1.9 and / or 0.002 ≤ H ≤ 0.02 and / or 10 ≤ A ≤ 100.

[0063] And / or means that any one of these three ranges can be selected, or any two of them can be selected, or all three can be selected.

[0064] When the above ranges are satisfied, while satisfying the overcurrent capacity of the tab 112 and preventing the tab 112 from being easily folded, the adsorption force or clamping force for the cutting operation is ensured.

[0065] If the value of H*A is too small, it is easy to fold, the welding quality between the tab 112 and the pole column is poor, affecting the overcurrent capacity of the tab 112, and it will also cause the internal resistance of the tab 112 to be too large due to heat generation, affecting the charge and discharge capacity of the battery. If the value of H*A is too large, on the one hand, there will be burrs and tearing problems formed during cutting of the tab 112, and it is not easy to bend, the adsorption force or clamping force during cutting operation positioning is insufficient, and the excessive occupied space will also affect the energy density of the battery.

[0066] Preferably, H*A can take values such as 0.021, 0.07, 0.01, 0.05, 0.2, 0.6, 1, 1.32, 1.48, 1.59, 1.84, 1.9, etc.

[0067] If the value of H is too small, the overcurrent capacity of the tab 112 is insufficient. For the battery during high-rate fast charging, the tab 112 generates a large amount of heat, the internal resistance of the battery is too large, and the battery has safety risks such as thermal control, and at the same time affects the overall charge and discharge rate of the battery; if the value of H is too large, it will cause the tab 112 to occupy a large space, affecting the space utilization rate of the battery, the energy density of the battery is small, and the adsorption force or clamping force during cutting operation positioning is insufficient.

[0068] Preferably, H can take values such as 0.002, 0.034, 0.085, 0.12, 0.15, 0.19, 0.02, etc.

[0069] If the value of A is too small, the tab 112 is likely to be folded, resulting in poor soldering between the tab 112 and the terminal post, affecting the soldering quality and further affecting the current-carrying capacity between the tab 112 and the terminal post; if the value of A is too large, there are many burrs when cutting the tab 112, the tab 112 is torn, the cutting size of the tab 112 is uneven, and it is not easy to bend the tab 112 subsequently, and the adsorption force or clamping force during the cutting operation positioning is insufficient.

[0070] Preferably, A can take values such as 10, 15, 30, 55, 69, 84, 97, 100, etc.

[0071] In some embodiments, the size L of the electrode tab body 111 in the third direction Y 1 mm, further satisfies: 50 ≤ L 1 ≤ 150.

[0072] If L 1 takes a too small value, the adsorption force or clamping force during the cutting operation positioning is insufficient; if L 1 takes a too large value, the current-carrying capacity of the tab 112 is insufficient.

[0073] Preferably, L 1 can take values such as 50, 65, 87, 101, 116, 125, 137, 142, 150, etc.

[0074] In some embodiments, the size L of the tab 112 in the third direction Y 2 mm, further satisfies: 20 ≤ L 2 ≤ 80.

[0075] If L 2 takes a too small value, the current-carrying capacity of the tab 112 is insufficient; if L 2 takes a too large value, the adsorption force or clamping force during the cutting operation positioning is insufficient.

[0076] Preferably, L 2 can take values such as 20, 26, 39, 54, 64, 78, 80, etc.

[0077] In some embodiments, the distance between the edge of the first end of the tab 112 in the third direction Y and the edge of the same-side end of the electrode tab body 111 in the third direction Y is d 1 mm, and the distance between the edge of the second end of the tab 112 in the third direction Y and the edge of the same-side end of the electrode tab body 111 in the third direction Y is d 2 mm, satisfying: d 1≠0 and d 2 ≠0, d 1 / d 2 ≤0.9 or d 1 / d 2 ≥1.1, 20 ≤ L 1 -L 2 ≤118.

[0078] d 1 ≠0 and d 2 ≠0, the edge of the tab 112 is not flush with any side edge of the tab body 111 in the third direction Y.

[0079] The tab 112 may not be provided at the center of the tab body 111. When the tab 112 is offset, the size of the cutting area on the offset side is small, and it is difficult to meet the adsorption force or clamping force of the cutting operation, and it is also difficult to accurately position the precise cutting position. When the above range is satisfied, the adsorption force or clamping force of the cutting operation can be satisfied, the stability of the adsorption or clamping of the cutting operation can be ensured, and the positioning accuracy of the cutting operation can be improved.

[0080] Preferably, L 1 -L 2 can take values such as 20, 24, 41, 62, 81, 98, 107, 115, 118, etc.

[0081] When measuring the measurement size d 1 and d 2 a common length measuring tool can be used, such as a ruler or a tape measure.

[0082] Specifically, when measuring d 1 in the third direction Y, taking the edge of the first end of the tab body 111 as the reference edge, through a length measuring tool, measuring the distance between the edge of the end of the tab 112 close to the reference edge and the reference edge, measuring multiple times and taking the average value, to obtain the distance d 1 mm between the edge of the first end of the tab in the third direction Y and the edge of the same side of the tab body 111 in the third direction Y.

[0083] When measuring d 2 in the third direction Y, taking the edge of the second end of the tab body 111 as the reference edge, through a length measuring tool, measuring the distance between the edge of the end of the tab 112 close to the reference edge and the reference edge, measuring multiple times and taking the average value, to obtain the distance d 2 mm between the edge of the second end of the tab 112 in the third direction Y and the edge of the same side of the tab body 111 in the third direction Y.

[0084] The first end and the second end are the two ends of the electrode tab body 111 in the third direction Y. In this embodiment, the first end is the end of the electrode tab body 111 on the side where the tab 112 is offset.

[0085] The distance d between the edge of the first end of the tab 112 in the third direction Y and the edge of one end of the electrode tab body 111 on the same side in the third direction Y 1 mm, also satisfies: 20 ≤ d 1 ≤ 80.

[0086] When the above range is satisfied, it can make the smaller-sized cutting area on the side where the tab 112 is offset also have sufficient adsorption force or clamping force to ensure the stability of adsorption or clamping during the cutting operation, and will not make the cut-off area too small to reduce the difficulty of accurately positioning the cutting position. In addition, it will not make the position of the tab 112 too offset to prevent the problem of uneven current flow.

[0087] Preferably, d 1 can take values such as 20, 32, 48, 53, 62, 71, 80, etc.

[0088] In some embodiments, d 1 ≠ 0 and d 2 ≠ 0, and 0.9 < d 1 / d 2 < 1.1, 22 ≤ L 1 – L 2 ≤ 120.

[0089] d 1 ≠ 0 and d 2 ≠ 0, the edge of the tab 112 is not flush with any side edge of the electrode tab body 111 in the third direction Y.

[0090] 0.9 < d 1 / d 2 < 1.1, the position of the tab 112 is closer to the center of the electrode tab body 111, having a better current-carrying effect. In addition, when cutting out the tab 112, the cut-off area is also easily satisfied with the clamping force or adsorption force required for the cutting operation, and relatively accurately positions the precise cutting position. Therefore, when 22 ≤ L 1 – L 2 ≤ 120, it can meet the adsorption force or clamping force of the cutting operation, ensure the stability of adsorption or clamping during the cutting operation, and improve the positioning accuracy of the cutting operation.

[0091] Preferably, L 1 -L 2 can take values such as 22, 29, 32, 47, 55, 67, 89, 109, 120, etc.

[0092] In some embodiments, d1 = 0 or d 2 = 0, 22 ≤ L 1 –L 2 ≤ 118.

[0093] d 1 = 0 or d 2 = 0, the edge of the tab 112 is flush with one side edge of the tab body 111 in the third direction Y.

[0094] In this case, the current-carrying effect of the tab 112 is relatively poor, and when cutting out the tab 112, compared with the cutting areas on both side edges of the tab 112 and the tab body 111 in the third direction Y, the area of the tab 112 with one side flush will be cut off more, and it is more difficult to meet the clamping force or adsorption force required for the cutting operation. Therefore, when 22 ≤ L 1 –L 2 ≤ 118, the adsorption force or clamping force for the cutting operation can be satisfied, ensuring the stability of adsorption or clamping during the cutting operation.

[0095] Preferably, L 1 -L 2 can take values such as 22, 33, 57, 62, 71, 88, 108, 115, 118, etc.

[0096] In some embodiments, the size of the tab body 111 in the second direction X is L 3 mm, satisfying: when 250 ≤ L 3 <350, 20 ≤ L 1 –L 2 ≤ 118; when 350 ≤ L 3 <550, 20 ≤ L 1 –L 2 ≤ 116; when L 3 ≥ 550, 20 ≤ L 1 –L 2 ≤ 114.

[0097] L 3 is the length of the tab body 111. To ensure the adsorption force or clamping force for the cutting operation, there are different requirements for the space provided for positioning the cutting area in different length range intervals. The larger the size of the tab 11, the greater the current-carrying demand for the tab 112, and the larger the size required for the current-carrying area of the tab 112. Among them, L 3 The larger the value, the more difficult it is to position the tab 112 during the cutting operation, and a greater adsorption force or clamping force is also required.

[0098] When the above range is satisfied, for the pole pieces 11 of different sizes, sufficient adsorption force or clamping force can be provided during the cutting operation, facilitating the smooth progress of the cutting operation while meeting the current-carrying requirements of the corresponding pole ears 112 of different sizes. However, as the value of L 3 increases, the pole piece body 111 becomes larger, there is more active material on the pole piece body 111, and the larger the current-carrying area required for the pole ear 112, to ensure the current-carrying capacity of the pole ear 111.

[0099] Preferably, when 250 ≤ L 3 <350, L 1 -L 2 can take values such as 20, 25, 39, 44, 69, 85, 92, 107, 118, etc.; when 350 ≤ L 3 <550, L 1 -L 2 can take values such as 20, 33, 41, 65, 74, 97, 100, 114, 116, etc.; when L 3 ≥550, L 1 -L 2 can take values such as 20, 36, 51, 67, 77, 94, 107, 114, etc.

[0100] In some embodiments, please refer to Figure 6 , the connection between the pole piece body 111 and the pole ear 112 has a right-angle transition, satisfying: 20 ≤ L 1 –L 2 ≤118. Preferably, L 1 -L 2 can take values such as 20, 21, 37, 58, 66, 79, 81, 99, 106, 112, 118, etc.

[0101] For the right-angle transition structure, during the cutting operation, the cut section and the pole ear 112 area are not likely to adhere, and the cutting efficiency is relatively high. However, the right-angle transition structure results in a worse current-carrying area for the pole ear 112 compared to the rounded transition. By setting the value of L 1 –L 2 within the above range, the current-carrying capacity of the pole ear 112 can be guaranteed to increase, and at the same time, the cutting yield of the pole piece 11 is not affected.

[0102] In some embodiments, please refer to Figure 5 , the connection between the pole piece body 111 and the pole ear 112 has a rounded transition, satisfying: 22 ≤ L 1 –L 2 ≤120. Preferably, L 1 -L 2 can take values such as 22, 23, 48, 53, 76, 88, 93, 109, 115, 120, etc.

[0103] The structure with rounded - corner transitions has a stronger current - carrying capacity for the tab 112 compared to the structure with right - angle transitions. However, it is prone to adhesion during the cutting operation. Therefore, a larger cutting size needs to be satisfied to avoid adhesion. Through the structure with rounded - corner transitions and setting L 1 –L 2 within the above - mentioned range can further compensate for the problem of the tab 112 being cut too large and having poor current - carrying capacity. At the same time, the adsorption force or clamping force cannot be too small to ensure the stability of adsorption or clamping during the cutting operation. In addition, the structural characteristics of the rounded - corner transition also make the position at the transition not easily torn.

[0104] In some embodiments, the radius of the rounded - corner at the connection between the electrode tab body 111 and the tab 112 is R mm, satisfying: 1 ≤ R ≤ 10. Preferably, R can take values such as 1, 3, 6, 8, 10, etc.

[0105] When satisfying the above range, it can not only meet the current - carrying requirements of the tab 112 but also avoid serious adhesion during the cutting operation. If R is too small, the problem of not being able to meet the current - carrying requirements will occur, and if R is too large, the problem of serious adhesion during the cutting operation will occur.

[0106] In some embodiments, please refer to Figure 7 , there is a reinforcing rib 1121 provided on the tab 112, satisfying: 20 ≤ L 1 –L 2 ≤ 118.

[0107] The setting of the reinforcing rib 1121 can improve the strength of the tab 112. The reinforcing rib 1121 can be set as regular shapes such as triangles, quadrilaterals, ellipses, etc., or can also be set as irregular shapes. The reinforcing rib 1121 can be separately fabricated and then connected to the tab 112 by welding, pasting, etc., or can be integrally formed with the tab 112.

[0108] Preferably, L 1 -L 2 can take values such as 20, 22, 49, 51, 62, 77, 81, 93, 106, 115, 118, etc.

[0109] In this embodiment, the reinforcing rib 1121 protrudes from the surface of the tab 112, and the shape of the reinforcing rib 1121 is strip - shaped and / or circular. "And / or" means that on the same tab 112, all the reinforcing ribs 1121 are circular, or all the reinforcing ribs 1121 are strip - shaped, or some of the reinforcing ribs 1121 are circular and the other part is strip - shaped. In addition, the reinforcing rib 1121 is formed by pressing the tab 112 to form an embossed form.

[0110] Please refer to Figure 8, the height by which the reinforcing rib 1121 protrudes from the tab 112 is t mm, satisfying: 0.001 ≤ t ≤ 0.018.

[0111] When within the above range, it can not only improve the cutting efficiency of the tab 112 during cutting, reduce the burrs of the tab 112, but also ensure the strength of the tab 112 itself and reduce the occurrence of adhesion problems during the cutting process. If the value of t is too small, the strength of the tab 112 itself cannot be guaranteed, and during the cutting process, the adsorption force or clamping force is also weak, making it prone to adhesion problems. If the value of t is too large, it is not easy to cut during the cutting operation, affecting the cutting efficiency, and there are also many burrs on the cut tab 112.

[0112] Preferably, t can take values such as 0.001, 0.007, 0.011, 0.013, 0.014, 0.018, etc.

[0113] In some embodiments, the electrode sheet body 111 is polygonal, and two adjacent sides of the electrode sheet body 111 form a corner, and the corner is a right angle, satisfying: 20 ≤ L 1 –L 2 ≤ 118.

[0114] In this embodiment, the electrode sheet body 111 is rectangular.

[0115] For a right-angle structure, it is not easy to adhere during the cutting operation, and the cutting efficiency is relatively high, and a large adsorption force or clamping force is not required. Therefore, within the above range, it can provide sufficient adsorption force or clamping force.

[0116] Preferably, L 1 –L 2 can take values such as 20, 23, 49, 59, 61, 72, 85, 97, 101, 112, 118, etc.

[0117] In some embodiments, the electrode sheet body 111 is polygonal, and two adjacent sides of the electrode sheet body 111 form a corner, and the corner is a rounded corner, satisfying: 22 ≤ L 1 –L 2 ≤ 120.

[0118] In this embodiment, the electrode sheet body 111 is rectangular.

[0119] For a rounded-corner structure, it can avoid the discharge at the sharp corners of the tab 112, but it is prone to adhesion during the cutting operation. Therefore, by increasing the cut size, the adsorption force or clamping force is ensured to guarantee the stability of adsorption or clamping during the cutting operation.

[0120] Preferably, L 1 –L 2 can take values such as 22, 27, 37, 46, 50, 71, 80, 91, 110, 120, etc.

[0121] In some embodiments, the electrode sheet 11 includes a positive electrode sheet 11 and a negative electrode sheet 11. The corners of the electrode sheet body 111 of the positive electrode sheet 11 are rounded, the corners of the electrode sheet body 111 of the negative electrode sheet 11 are right-angled, and the size of the body of the negative electrode sheet 11b is larger than that of the body of the positive electrode sheet 11a.

[0122] In the manufacturing process of the stacked cell 1, the setting method of the negative electrode over the positive electrode can prevent the corners of the positive electrode sheet 11 from piercing the separator and the negative electrode through such a structure, thereby improving the yield rate of the stacked cell 1.

[0123] By setting the corners of the electrode sheet body 111 of the positive electrode sheet 11a as rounded corners and the corners of the electrode sheet body 111 of the negative electrode sheet 11b as right-angled corners, the ear 112 can be prevented from sticking during the cutting process, while ensuring the insulation safety of the positive and negative electrode sheets 11b, and reducing the risk of insulation short-circuit failure caused by the positive electrode sheet 11a piercing the separator at a right angle and the overlapping of the negative electrode sheet 11b.

[0124] Please refer to Figure 9 , the battery further includes a housing 2 and a cover plate 3. The housing 2 has an opening, the cover plate 3 is provided on the opening, the cover plate 3 and the housing 2 form a receiving space, and at least a part of the stacked cell 1 is disposed in the receiving space.

[0125] The stacked cell 1 can enter the interior of the housing 2 through the opening. The cover plate 3 covering the opening can make the receiving space in a sealed state. The cover plate 3 is provided with electrode posts for electrically connecting the stacked cell 1 and the outside of the battery, and the cover plate 3 is also provided with a pressure relief mechanism for bursting when the battery undergoes thermal runaway.

[0126] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A battery, characterized in that: include: A laminated battery cell, comprising a plurality of pole pieces stacked in layers along a first direction, wherein the pole pieces comprise a pole piece body and a pole ear, wherein the pole ear is led out from the pole piece body along a second direction, wherein the size of the pole piece body in a third direction is L1 mm, and the size of the pole ear in the third direction is L2 mm, and the following conditions are satisfied: 20≤L1–L2≤120; The first direction, the second direction and the third direction are perpendicular to each other.

2. The battery according to claim 1, characterized in that: The dimension of the tab in the first direction is H mm, and the hardness of the tab is A HRB, satisfying: 0.0003≤(H*A) / (L1−L2)≤0.

08.

3. The battery according to claim 2, characterized in that: The thickness H mm of the tab and the hardness A HRB of the tab further satisfy: 0.021≤H*A≤1.9 and / or 0.002≤H≤0.02 and / or 10≤A≤100.

4. The battery according to claim 1, characterized in that: The dimension L1 of the pole piece body in the third direction also satisfies: 50≤L1≤150.

5. The battery according to claim 1, characterized in that: The dimension L2 mm of the tab in the third direction also satisfies: 20≤L2≤80.

6. The battery according to claim 1, characterized in that: The distance between the edge of the first end of the pole ear in the third direction and the edge of one end of the pole piece body on the same side of the third direction is d1 mm, and the distance between the edge of the second end of the pole ear in the third direction and the edge of one end of the pole piece body on the same side of the third direction is d2 mm, satisfying: d1≠0 and d2≠0, d1 / d2≤0.9 or d1 / d2≥1.1, 20≤L1–L2≤118.

7. The battery according to claim 6, characterized in that: The distance d1 mm between the edge of the first end of the pole ear in the third direction and the edge of one end of the pole piece body on the same side of the third direction also satisfies: 20≤d1≤80.

8. The battery according to claim 1, characterized in that: The distance between the edge of the first end of the pole ear in the third direction and the edge of one end of the pole piece body on the same side of the third direction is d1 mm, and the distance between the edge of the second end of the pole ear in the third direction and the edge of one end of the pole piece body on the same side of the third direction is d2 mm, satisfying: d1≠0 and d2≠0, and when 0.9<d1 / d2<1.1, 22≤L1–L2≤120.

9. The battery according to claim 1, characterized in that: The distance between the edge of the first end of the pole ear in the third direction and the edge of one end of the pole piece body on the same side of the third direction is d1 mm, and the distance between the edge of the second end of the pole ear in the third direction and the edge of one end of the pole piece body on the same side of the third direction is d2 mm, satisfying: d1=0 or d2=0, 22≤L1–L2≤118.

10. The battery according to any one of claims 1 to 9, characterized in that: The size of the pole piece body in the second direction is L3 mm, satisfying: When 250≤L3<350, 20≤L1–L2≤118; When 350≤L3<550, 20≤L1–L2≤116; When L3 ≥ 550, 20 ≤ L1–L2 ≤ 114.

11. The battery according to claim 1, characterized in that: The connection between the pole piece body and the pole ear is in a right angle transition, satisfying: 20≤L1-L2≤118.

12. The battery according to claim 1, characterized in that: The connection between the pole piece body and the pole ear has a rounded transition, which satisfies: 22≤L1-L2≤120.

13. The battery according to claim 12, characterized in that: The radius of the fillet at the connection between the pole piece body and the pole ear is R mm, satisfying: 1≤R≤10.

14. The battery according to any one of claims 1 to 7, characterized in that: The pole lug is provided with reinforcing ribs satisfying: 20≤L1–L2≤118.

15. The battery according to claim 14, characterized in that: The reinforcing rib protrudes from the surface of the pole lug, and the shape of the reinforcing rib is strip and / or circular.

16. The battery according to claim 15, characterized in that: The height of the reinforcing rib protruding from the surface of the tab is t mm, satisfying: 0.001≤t≤0.

018.

17. The battery according to claim 1, characterized in that: The pole piece body is polygonal, and two adjacent sides of the pole piece body form an angle, and the angle is a right angle, satisfying: 20≤L1-L2≤118.

18. The battery according to claim 1, characterized in that: The pole piece body is polygonal, and two adjacent sides of the pole piece body form a corner, and the corner is rounded and satisfies: 22≤L1-L2≤120.

19. The battery according to claim 1, characterized in that: The pole pieces include a positive pole piece and a negative pole piece. The pole piece body of the positive pole piece has rounded corners, the pole piece body of the negative pole piece has right angles, and the size of the negative pole piece body is larger than that of the positive pole piece body.

20. The battery according to any one of claims 1 to 9, characterized in that: a housing having an opening; A cover plate is arranged at the opening, the cover plate and the shell form a receiving space, and the laminated battery core is at least partially arranged in the receiving space.

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