Core stacking structure and battery

Abstract

The utility model provides a laminated core structure and a battery, and relates to the technical field of batteries. The laminated core structure comprises a plurality of positive plates, a plurality of negative plates and a plurality of diaphragms; a first groove and a second groove are formed in the side, in the first direction of the diaphragm, of the positive plate, a third groove and a fourth groove are formed in the side, in the first direction of the diaphragm, of the negative plate, the first groove corresponds to the fourth groove in the thickness direction of the diaphragm, and the second groove corresponds to the third groove in the thickness direction of the diaphragm; and soft tabs are formed in the first groove and the third groove. The two sides of the position, corresponding to the soft tab, of each diaphragm in the length direction of the diaphragm are provided with the notches respectively, so that the parts, located on the two sides of the notches, of each diaphragm are broken, the positions, where the notches are located, of the diaphragms are discontinuous, and the soft tab can be freely bent and is not restrained by the diaphragms; therefore, the space at the root of the soft tab can be saved, and the energy density of the battery can be further improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a stacked core structure and battery. Background Technology

[0002] With the rapid development of battery technology, people have placed higher demands on the energy density of batteries.

[0003] In related technologies, a battery includes a casing and a stack of cores, with the cores and electrolyte disposed within the casing. The stack of cores includes multiple positive electrode plates, multiple separators, and multiple negative electrode plates, formed by sequentially stacking the positive electrode plates, separators, and negative electrode plates. Each positive electrode plate forms a positive flexible tab, and each negative electrode plate forms a negative flexible tab. Two grooves are provided on one side of the stack of cores. A portion of the positive flexible tab corresponding to the positive electrode plate and a portion of the negative flexible tab corresponding to the negative electrode plate are located in the two grooves, respectively. The positive and negative flexible tabs in the two grooves are bent and welded to a rigid tab, respectively.

[0004] However, there is unused space at the root of the positive and negative soft electrodes, resulting in low energy density of the battery. Utility Model Content

[0005] This utility model provides a stacked core structure and battery to solve the problem of low battery energy density caused by the presence of idle space at the roots of the positive and negative electrode tabs.

[0006] On the one hand, this utility model provides a stacked core structure, including multiple positive electrode sheets, multiple negative electrode sheets and multiple separators, wherein the positive electrode sheets, the separators and the negative electrode sheets are alternately stacked to form the stacked core structure;

[0007] The positive electrode sheet has a first groove and a second groove on one side of the separator in a first direction, and the negative electrode sheet has a third groove and a fourth groove on one side of the separator in a first direction. The first groove corresponds to the fourth groove in the thickness direction of the separator, and the second groove corresponds to the third groove in the thickness direction of the separator. Soft electrode tabs are formed in both the first groove and the third groove. The soft electrode tabs include a positive soft electrode tab located in the first groove and a negative soft electrode tab located in the third groove.

[0008] Along the length of the diaphragm, each diaphragm has slits on both sides at the position corresponding to the soft electrode tab, and the length L1 of the slit (301) is less than the length S3 of the third groove (403);

[0009] The ratio of the length L1 of the cut (301) to the length S3 of the third groove (403) is 80%-95%.

[0010] In one possible implementation, in the first direction of the diaphragm, the length of the first groove is S1, the length of the second groove is S2, the length of the third groove is S3, and the length of the fourth groove is S4.

[0011] S3 satisfies: S3 < S2; and / or,

[0012] The condition S4 satisfies: S4 < S1.

[0013] In one possible implementation, along the length of the diaphragm, the distance between the two slits corresponding to the positive and negative soft electrode tabs is Q1, the distance between the slits and the solder mark is Q2, the width of the hard electrode tab is T, and Q2 satisfies: Q2 = (Q1 - T) / 2 + b, where b is less than 0.35 mm; and / or,

[0014] The Q2 satisfies: Q2 = (Q1 - T) / 2 - b, where b is less than 0.35 mm; and / or,

[0015] The Q1 is greater than or equal to 4 mm and less than or equal to 15 mm.

[0016] In one possible implementation, the length of the stacked core structure is L2 in the length direction of the diaphragm, the ratio of Q2 to L2 is greater than or equal to 0.2% and less than or equal to 3%, and / or, each of the positive electrode soft tabs and each of the negative electrode soft tabs are welded to a hard tab (50) to form a solder mark (405), the projection of the solder mark (405) in the thickness direction of the positive electrode sheet (10) and the projection of the diaphragm (30) do not overlap.

[0017] In one possible implementation, the width of the cut in the longitudinal direction of the diaphragm is less than or equal to 1 mm.

[0018] In one possible implementation, at least one of the diaphragms is provided with a clearance portion located between two adjacent cuts, and the clearance portion and the solder mark form a clearance area.

[0019] In one possible implementation, the diaphragm includes a body connected to the clearance portion, wherein the ratio of the thickness of the clearance portion to the thickness of the body is greater than or equal to 1.02 and less than or equal to 1.1 in the thickness direction of the diaphragm.

[0020] In one possible implementation, in a first direction of the diaphragm, the end of the abutment portion away from the solder mark is designated as the first end, and the end of the diaphragm closer to the solder mark is designated as the second end. The distance between the first end and the second end is L3, and the distance between the first end and the solder mark is W1. The ratio of L3 to W1 is greater than or equal to 0.1 and less than or equal to 0.95; and / or,

[0021] In the first direction of the separator, the distance between the clearance portion and the edge of the positive electrode sheet is W3, the width of the stacked core structure is W4, and the ratio of W3 to W4 is greater than or equal to 3% and less than or equal to 7%.

[0022] In one possible implementation, in the length direction of the diaphragm, the width of the clearance portion is L4, the width of the solder mark is W2, and the ratio of L4 to W2 is greater than or equal to 0.8 and less than or equal to 1.2.

[0023] In one possible implementation, in the thickness direction of the diaphragm, the stacked core structure has a bottom edge and a top edge disposed opposite to each other, the distance between the side of the clearance portion away from the bottom edge and the bottom edge is H3, the thickness of the stacked core structure is H4, and the ratio of H3 to H4 is greater than or equal to 5% and less than or equal to 20%; and / or,

[0024] The H3 is greater than or equal to 0.1 mm and less than or equal to 0.5 mm.

[0025] On the other hand, this utility model embodiment provides a battery including the stacked core structure described above.

[0026] This utility model provides a stacked core structure and battery. By providing slits on both sides of each separator along its length, corresponding to the position of the flexible tab, the portion of each separator located on both sides of the slit can be broken. The separator is discontinuous at the position of the slit, so that the separator does not affect the bending of the flexible tab. The flexible tab can be bent freely without being constrained by the separator, thereby saving space at the root of the flexible tab and thus improving the energy density of the battery.

[0027] Each separator has slits on both sides corresponding to the soft tab, effectively separating the separator portion at the slits. This eliminates the need to remove the separator, preventing adhesive from mixing into the weld and improving the welding strength between the soft and hard tabs. It also increases the current-carrying capacity at the weld, facilitating fast charging and discharging. Furthermore, the length L1 of the slit (301) is less than the length S3 of the third groove (403). The ratio of the length L1 of the slit (301) to the length S3 of the third groove (403) is 80%-95%, ensuring the separation of the separator gaps. The bottom edge of the separator remains higher than the bottom edge of the third and / or fourth groove to prevent powder from easily falling from the edge of the negative electrode sheet on the edge of the third or fourth groove and landing on the corresponding positive electrode sheet, causing a short circuit. Simultaneously, the cut in the separator and the separator between the cuts can suppress the edge expansion of the negative electrode sheet doped with silicon-carbon composite material, preventing breakage of the edge of the negative electrode sheet or the flexible tab due to expansion. When the ratio of L1 to S3 is less than or equal to 0.8, the length of the cut 301 is too small, resulting in insufficient bending at the root of the flexible tab 40, leaving unused space at the root of the flexible tab 40 and leading to low battery energy density. When the ratio of L1 to S3 is greater than or equal to 0.95, the negative electrode sheet 20 may come into contact during the cutting of the separator 30 to form the cut 301, causing damage to the negative electrode sheet 20 and thus reducing battery capacity. In other words, by limiting the length of the cut 301, space at the root of the flexible tab 40 can be saved, increasing the battery energy density while ensuring that the negative electrode sheet 20 is not damaged. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a stacked core structure provided in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the alternating stacking of a positive electrode sheet, a separator, and a negative electrode sheet according to an embodiment of the present invention, wherein the positive electrode sheet and the negative electrode sheet are respectively formed with soft electrode tabs;

[0031] Figure 3 for Figure 2 A schematic diagram showing the soft electrode tab after it has been bent and welded to the hard electrode tab.

[0032] Figure 4 for Figure 3A schematic diagram showing the soft electrode tab being bent into the first and second grooves after the soft electrode tab and hard electrode tab are welded together.

[0033] Figure 5 for Figure 4 An enlarged diagram of point A in the diagram.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10-Positive electrode sheet; 20-Negative electrode sheet; 30-Separator; 30a-Body; 301-Cut-out; 302-Allowing part; 40-Soft tab; 401-First groove; 402-Second groove; 403-Third groove; 404-Fourth groove; 405-Solder mark; 50-Hard tab; 10a-Bottom edge; 10b-Top edge. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0037] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0039] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] In the above description, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0041] As described in the background section, there is unused space at the base of the positive and negative electrode tabs, resulting in low battery energy density. The inventors discovered that this problem arises because a portion of the positive electrode tab is bonded to the separator. When the positive electrode tab is bent, the separator restricts its bending, preventing it from bending freely. Similarly, a portion of the negative electrode tab is also bonded to the separator. This restriction, caused by the separator, results in unused space at the base of both the positive and negative electrode tabs, leading to low battery energy density.

[0042] To address the aforementioned issues, this utility model provides a stacked core structure and battery. By cutting the separator, the separator does not affect the bending of the flexible tabs. The flexible tabs can be bent freely without being constrained by the separator, thereby saving space at the root of the flexible tabs and thus improving the energy density of the battery.

[0043] In related technologies, the diaphragm on the flexible tab is removed to avoid affecting its bending ability, allowing it to bend freely. However, residual adhesive from the diaphragm on the flexible tab may get into the weld, reducing the weld strength between the flexible and rigid tabs.

[0044] This utility model provides a stacked core structure and battery. By cutting the separator instead of removing it, the separator adhesive can be prevented from mixing into the weld, the welding strength of the soft tab and the hard tab can be improved, and the current carrying capacity of the weld can be increased, which is beneficial for the battery to charge and discharge quickly.

[0045] The stacked core structure and battery provided in this utility model embodiment will be described in detail below with reference to specific embodiments.

[0046] See Figure 1 As shown, this utility model embodiment provides a stacked core structure, including multiple positive electrode plates 10, multiple negative electrode plates 20 and multiple separators 30.

[0047] The width direction of the diaphragm 30 is the X-axis direction, and the width direction of the stacked core structure is the same as the width direction of the diaphragm 30; the length direction of the diaphragm 30 is the Y-axis direction (see...). Figure 2 As shown, the length direction of the stacked core structure is the same as the length direction of the diaphragm 30; the thickness direction of the diaphragm 30 is the Z-axis direction, and the thickness direction of the stacked core structure is the same as the thickness direction of the diaphragm 30. The X-axis, Y-axis and Z-axis are perpendicular to each other.

[0048] Within the plane defined by the X and Y axes, the area of ​​the positive electrode 10 is smaller than the area of ​​the negative electrode 20, and the area of ​​the negative electrode 20 is smaller than the area of ​​the separator 30.

[0049] In the thickness direction of the separator 30, the positive electrode 10, the separator 30 and the negative electrode 20 are alternately stacked to form a stacked core structure.

[0050] See 2 and Figure 3 As shown, the positive electrode 10 has a first groove 401 and a second groove 402 on one side of the separator 30 in the first direction, and the negative electrode 20 has two third grooves 403 and a fourth groove 404 on one side of the separator 30 in the first direction. The first groove 401 corresponds to the fourth groove 404 in the thickness direction of the separator 30, and the second groove 402 corresponds to the third groove 403 in the thickness direction of the separator 30. In this embodiment, the first direction of the separator 30 can be the width direction of the separator 30.

[0051] The first groove 401 and the second groove 402 are spaced apart along the length of the separator 30. The first groove 401 and the second groove 402 penetrate the positive electrode sheet 10 in the thickness direction of the separator 30.

[0052] The third groove 403 and the fourth groove 404 are spaced apart along the length of the separator 30. The third groove 403 and the fourth groove 404 penetrate the negative electrode sheet 20 in the thickness direction of the separator 30.

[0053] Soft electrode tabs 40 are formed in both the first groove 401 of the positive electrode 10 and the third groove 403 of the negative electrode 20. Specifically, a positive soft electrode tab is formed in one of the first grooves 401 of the positive electrode 10, and a negative soft electrode tab is formed in one of the third grooves 403 of the negative electrode 20. That is to say, the soft electrode tabs 40 include the positive soft electrode tab located in the first groove 401 and the negative soft electrode tab located in the third groove 403.

[0054] The positive electrode soft tab in the first groove 401 of the positive electrode 10 and the negative electrode soft tab in the third groove 403 of the negative electrode 20 are spaced apart along the length of the separator 30.

[0055] The projections of the soft tabs 40 corresponding to each positive electrode 10 in the stacked core structure overlap in the thickness direction of the separator 30.

[0056] The projections of the soft tabs 40 corresponding to each negative electrode sheet 20 in the stacked core structure overlap in the thickness direction of the diaphragm 30.

[0057] exist Figure 2 In the middle, the soft electrode tab 40 is not bent relative to the positive electrode 10 and the negative electrode 20.

[0058] See Figure 2 As shown, along the length of the diaphragm 30, each diaphragm 30 has slits 301 on both sides at positions corresponding to the flexible tabs 40. Specifically, along the length of the diaphragm 30, each diaphragm 30 has slits 301 on both sides at positions corresponding to the positive flexible tab and on both sides at positions corresponding to the negative flexible tab. The length L1 of the slit 301 is less than the length S3 of the third groove 403; the ratio of the length L1 of the slit 301 to the length S3 of the third groove 403 is 80%-95%.

[0059] The portions of each diaphragm 30 located on either side of the cut 301 are discontinuous. This arrangement ensures that the diaphragms 30 are not continuous at the location of the cut 301, so that the diaphragms 30 do not affect the bending of the flexible tabs 40, allowing the flexible tabs 40 to bend freely without being constrained by the diaphragms 30.

[0060] In some examples, the diaphragm 30 is cut using a mold or laser to form a cut 301.

[0061] exist Figure 3 In this process, each positive and negative soft electrode tab is welded to a hard electrode tab 50 to form a solder mark 405. It can be understood that each positive soft electrode tab is welded to a hard electrode tab 50 to form a solder mark 405, and each negative soft electrode tab is welded to a hard electrode tab 50 to form a solder mark 405.

[0062] The stacked core structure provided in this embodiment of the utility model has a slit 301 on each side of the separator 30 at the position corresponding to the flexible tab 40 along the length direction of the separator 30. The portions of each separator 30 on both sides of the slit 301 are discontinuous, so that the separator 30 does not affect the bending of the flexible tab 40. The flexible tab 40 can be bent freely without being constrained by the separator 30, thereby saving space at the root of the flexible tab 40 and thus improving the energy density of the battery. At the same time, the length L1 of the slit (301) is less than the length S3 of the third groove (403). This ensures that the bottom of the notch of the separator is still higher than the bottom edge of the third groove and / or the fourth groove, preventing the edge of the negative electrode sheet on the edge of the third groove or the fourth groove from easily shedding powder, which falls onto the corresponding positive electrode sheet and causes a short circuit. At the same time, the slit of the separator and the separator between the slits can also suppress the edge expansion of the negative electrode sheet doped with silicon-carbon composite material, preventing the edge of the negative electrode sheet or the flexible tab from expanding and breaking.

[0063] See in some examples Figure 2 As shown, L1 satisfies: L1 = a * S3, where a is greater than 0.8 and less than 0.95. For example, the ratio of L1 to S3 can be 0.81, 0.83, 0.85, 0.87, 0.89, 0.9, 0.92, 0.93, or 0.94. Of course, this ratio can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the ratio of L1 to S3 is less than or equal to 0.8, the length of the cut 301 is too small, and the root of the soft electrode 40 will not be bent sufficiently, resulting in idle space at the root of the soft electrode 40, leading to low energy density of the battery. When the ratio of L1 to S3 is greater than or equal to 0.95, the negative electrode 20 may come into contact during the process of cutting the separator 30 to form the cut 301, causing damage to the negative electrode 20, thereby reducing the battery capacity. In other words, by limiting the length of the cut 301, space at the root of the soft tab 40 can be saved, the energy density of the battery can be increased, and the negative electrode 20 can be protected from damage.

[0064] See in some examples Figure 2As shown, L1 satisfies: L1 = a * S4, where a is greater than 0.8 and less than 0.95. For example, the ratio of L1 to S4 can be 0.81, 0.83, 0.85, 0.87, 0.89, 0.9, 0.92, 0.93, or 0.94. Of course, this ratio can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the ratio of L1 to S4 is less than or equal to 0.8, the length of the cut 301 is too small, and the root of the soft electrode 40 will not be bent sufficiently, resulting in idle space at the root of the soft electrode 40, leading to low energy density of the battery. When the ratio of L1 to S4 is greater than or equal to 0.95, the negative electrode 20 may come into contact during the process of cutting the separator 30 to form the cut 301, causing damage to the negative electrode 20, thereby reducing the battery capacity. In other words, by limiting the length of the cut 301, space at the root of the soft tab 40 can be saved, the energy density of the battery can be increased, and the negative electrode 20 can be protected from damage.

[0065] In one possible implementation, in the first direction of the diaphragm 30, the length of the cut 301 is L1, the length of the first groove 401 is S1, the length of the second groove 402 is S2, the length of the third groove 403 is S3, and the length of the fourth groove 404 is S4.

[0066] Wherein, S3 satisfies: L1 < S3 < S2. By ensuring that S3 < S2, it can be guaranteed that the negative electrode 20 can cover the positive electrode 10; by ensuring that L1 < S3, the negative electrode 20 can be contacted during the process of cutting the separator 30 to form the cut 301.

[0067] S4 satisfies: L1 < S4 < S1. By ensuring that S4 < S1, it can be guaranteed that the negative electrode 20 can cover the positive electrode 10; by ensuring that L1 < S4, the negative electrode 20 can be contacted during the process of cutting the separator 30 to form the cut 301.

[0068] It should be noted that, along the length of the diaphragm 30, the width of the first groove 401 is greater than the width of the fourth groove 404, and the width of the second groove 402 is greater than the width of the third groove 403.

[0069] In some examples, S1 can be equal to S2, and S3 can be equal to S4.

[0070] In one possible implementation, the distance between the two cuts 301 corresponding to the positive electrode soft tab and the negative electrode soft tab in the length direction of the diaphragm 30 is Q1. That is, in the length direction of the diaphragm 30, the distance between the two cuts 301 corresponding to the positive electrode soft tab is Q1, and the distance between the two cuts 301 corresponding to the negative electrode soft tab is Q1.

[0071] The distance between the cut 301 and the solder mark 405 is Q2, and the width of the rigid tab 50 is T. Q2 satisfies: Q2 = (Q1 - T) / 2 + b, where b is less than 0.35 mm. That is, the difference between Q2 and (Q1 - T) / 2 is b. It can be understood that, along the length of the diaphragm 30, the center line of the two cuts 301 is located between one of the two cuts 301 of the soft tab 40 and the solder mark 405. For example, the difference between Q2 and (Q1 - T) / 2 can be 0 mm, 0.05 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, or 0.35 mm. Of course, this difference can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the difference between Q2 and (Q1-T) / 2 is greater than or equal to 0.35 mm, the distance between the cut 301 and the solder mark 405 becomes too great. During the process of cutting the separator 30 to form the cut 301, it may come into contact with the positive electrode 10 and the negative electrode 20, causing damage to the positive electrode 10 and the negative electrode 20, thereby reducing the battery capacity. In other words, by limiting the difference between Q2 and (Q1-T) / 2, the positive electrode 10 and the negative electrode 20 can be prevented from being damaged during the process of cutting the separator 30 to form the cut 301.

[0072] In another possible implementation, along the length of the diaphragm 30, the distance between the two cuts 301 corresponding to the positive and negative flexible tabs is Q1, the distance between the cuts 301 and the solder mark 405 is Q2, and the width of the rigid tab 50 is T. Q2 satisfies: Q2 = (Q1 - T) / 2 - b, where b is less than 0.35 mm. That is, the difference between (Q1 - T) / 2 and Q2 is b. It can be understood that, along the length of the diaphragm 30, the center line of the two cuts 301 is not between one of the two cuts 301 corresponding to the flexible tab 40 and the solder mark 405. For example, the difference between (Q1 - T) / 2 and Q2 can be 0 mm, 0.05 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, or 0.35 mm. Of course, this difference can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the difference between (Q1-T) / 2 and Q2 is greater than or equal to 0.35mm, the cut 301 and the solder mark 405 become too close. During the process of cutting the separator 30 to form the cut 301, the separator 30 may come into contact with the soft tab 40 and the hard tab 50, causing damage to the soft tab 40 and the hard tab 50, thereby reducing the battery capacity. In other words, by limiting the difference between (Q1-T) / 2 and Q2, the soft tab 40 and the hard tab 50 can be prevented from being damaged during the process of cutting the separator 30 to form the cut 301.

[0073] For example, the value of b can be greater than 0.1 mm and less than 0.35 mm.

[0074] In one possible implementation, along the length of the separator 30, the distance between the two cuts 301 corresponding to the positive and negative flexible tabs is Q1, where Q1 is greater than or equal to 4 mm and less than or equal to 15 mm. For example, Q1 can be 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 13 mm, or 15 mm. Of course, other values ​​are also possible, and those skilled in the art can choose according to their needs; this embodiment does not limit this. When Q1 is less than 4 mm, the distance between the two cuts 301 is too small, and the flexible tab 40 may be damaged during the cutting process of the separator 30 to form the cuts 301, resulting in a reduction in the current carrying capacity of the flexible tab 40, which is not conducive to fast charging and discharging of the battery. When Q1 is greater than 15mm, the distance between the two cuts 301 is too large. During the process of cutting the diaphragm 30 to form the cuts 301, the electrode sheets on both sides of the first groove 401 and the fourth groove 404, as well as the electrode sheets on both sides of the second groove 402 and the third groove 403, may be damaged, resulting in electrode powder shedding and affecting energy density. In other words, by limiting the distance between the two cuts 301, it can be ensured that the electrode sheets are not damaged.

[0075] In one possible implementation, the length of the stacked core structure in the longitudinal direction of the separator 30 is L2, and the ratio of Q2 to L2 is greater than or equal to 0.2% and less than or equal to 3%. For example, the ratio of Q2 to L2 can be 0.2%, 0.5%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, or 3%. Of course, this ratio can also be other values, and those skilled in the art can choose according to their needs; this embodiment does not limit this. When the ratio of Q2 to L2 is less than 0.2%, the distance between the cut 301 and the solder mark 405 is too small. During the process of cutting the separator 30 to form the cut 301, the soft tab 40 may be damaged, resulting in a reduction in the current carrying capacity of the soft tab 40, which is not conducive to fast charging and discharging of the battery. When the ratio of Q2 to L2 is greater than 3%, the distance between the cut 301 and the solder mark 405 is too large. During the process of cutting the diaphragm 30 to form the cut 301, the electrode sheets on both sides of the first groove 401 and the fourth groove 404, as well as the electrode sheets on both sides of the second groove 402 and the third groove 403, may be damaged, resulting in electrode powder shedding and affecting energy density. In other words, by limiting the distance between the cut 301 and the solder mark 405, it can be ensured that the electrode sheets are not damaged.

[0076] In one possible implementation, the width of the cut 301 along the length of the separator 30 is less than or equal to 1 mm. For example, the width of the cut 301 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 0.95 mm, or 1 mm. Of course, the width of the cut 301 can also be other values, and those skilled in the art can choose according to their needs; this embodiment does not limit this. When the width of the cut 301 is greater than 1 mm, the positive electrode 10, negative electrode 20, and flexible tab 40 may come into contact during the process of cutting the separator 30 to form the cut 301, causing damage to the positive electrode 10, negative electrode 20, and flexible tab 40, thereby reducing the battery capacity. That is to say, by limiting the width of the cut 301, it is possible to ensure that the positive electrode 10, negative electrode 20, and flexible tab 40 are not damaged during the process of cutting the separator 30 to form the cut 301.

[0077] In one possible implementation, see Figure 3 As shown, at least one separator 30 is provided with a clearance portion 302, which is located between two adjacent cuts 301. The clearance portion 302 and the solder mark 405 form a clearance area. In order to improve the space utilization of the battery, the solder mark 405 formed by welding the soft tab 40 and the hard tab 50 is close to the separator 30. If the clearance portion 302 is not provided on the separator 30, the separator 30 will be mixed into the solder mark 405, resulting in reduced welding strength, or even a poor weld, and a short circuit in the stacked core structure due to pulling the separator 30. In this embodiment, by providing a clearance portion 302 on at least one separator 30, the separation portion 30 can be prevented from being mixed into the solder mark 405, resulting in reduced welding strength, or even a poor weld, and a short circuit in the stacked core structure due to pulling the separator 30.

[0078] The clearance section 302 can be formed by thermal shrinkage.

[0079] The stacked core structure may have a clearance portion 302 provided on one diaphragm 30 or multiple diaphragms 30. In some examples, the stacked core structure has a bottom edge 10a and a top edge 10b disposed opposite each other in the thickness direction of the diaphragms 30. The clearance portion 302 is provided on the diaphragm 30 furthest from the bottom edge 10a in the stacked core structure.

[0080] In one possible implementation, the diaphragm 30 includes a body 30a connected to the clearance portion 302 (see [link]). Figure 2 (As shown). It should be noted that the part remaining after removing the avoidance part 302 from the diaphragm 30 is the body 30a.

[0081] In the thickness direction of the diaphragm 30, the ratio of the thickness of the clearance portion 302 to the thickness of the body 30a is greater than or equal to 1.02 and less than or equal to 1.1. For example, the ratio of the thickness of the clearance portion 302 to the thickness of the body 30a can be 1.02, 1.04, 1.06, 1.08, or 1.1. Of course, this ratio can also be other values, and those skilled in the art can choose according to their needs; this embodiment does not limit this. When the ratio of the thickness of the clearance portion 302 to the thickness of the body 30a is less than 1.02, the clearance area formed by the clearance portion 302 and the solder mark 405 is too small, and the diaphragm 30 will still be mixed into the solder mark 405, causing a poor solder joint. When the ratio of the thickness of the clearance portion 302 to the thickness of the main body is greater than 1.1, the clearance area formed by the clearance portion 302 and the solder mark 405 is too large, resulting in insufficient coverage of the positive electrode 10 and the negative electrode 20 by the separator 30, posing a short-circuit safety risk during battery operation. In other words, by limiting the ratio of the thickness of the clearance portion 302 to the thickness of the main body 30a, the separator 30 is prevented from being incorporated into the solder mark 405, while ensuring sufficient coverage of the positive electrode 10 and the negative electrode 20 by the separator 30.

[0082] In one possible implementation, see Figure 3 As shown, in the first direction of the separator 30, the end of the clearance portion 302 away from the solder mark 405 is the first end 3021, and the end of the separator 30 close to the solder mark 405 is the second end 30a1. The distance between the first end 3021 and the second end 30a1 is L3, and the distance between the first end 3021 and the solder mark 405 is W1. The ratio of L3 to W1 is greater than or equal to 0.1 and less than or equal to 0.95. For example, the ratio of L3 to W1 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 0.95. Of course, this ratio can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the ratio of L3 to W1 is less than 0.1, the distance between the separator 30 and the solder mark 405 becomes too large, resulting in insufficient space utilization on one side of the separator 30 in the first direction, leading to wasted space and low energy density of the battery. When the ratio of L3 to W1 is greater than 0.95, the distance between the separator 30 and the solder mark 405 becomes too small. This results in an excessively large clearance area formed by the separator and the solder mark 405 through heat shrinkage, leading to insufficient coverage of the positive electrode 10 and the negative electrode 20 by the separator 30. This poses a short-circuit safety risk during battery operation. In other words, by limiting the ratio of L3 to W1, wasted space can be avoided while ensuring sufficient coverage of the positive electrode 10 and the negative electrode 20 by the separator 30.

[0083] In one possible implementation, the width of the clearance portion 302 along the length of the separator 30 is L4, and the width of the solder mark 405 is W2. The ratio of L4 to W2 is greater than or equal to 0.8 and less than or equal to 1.2. For example, the ratio of L4 to W2 can be 0.8, 0.9, 1, 1.1, or 1.2. Of course, this ratio can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the ratio of L4 to W2 is less than 0.8, the width of the clearance portion 302 is too small, and the separator 30 will still be mixed into the solder mark 405, resulting in a reduction in welding strength. When the ratio of L4 to W2 is greater than 1.2, the width of the clearance portion 302 is too large, resulting in insufficient coverage of the positive electrode 10 and the negative electrode 20 by the separator 30, which poses a short circuit safety risk during battery operation. In other words, by limiting the ratio of the width of the clearance portion 302 to the width of the solder mark 405, the separator 30 can be prevented from being mixed into the solder mark 405, while ensuring that the separator 30 provides sufficient coverage for the positive electrode 10 and the negative electrode 20.

[0084] It should be noted that, in Figure 3 In the process of welding multiple positive electrode tabs 10 to multiple rigid electrode tabs 50, and welding multiple negative electrode tabs 20 to multiple rigid electrode tabs 50, it is necessary to bend and stack the multiple positive electrode tabs 10 together, and the multiple negative electrode tabs 20 together; Figure 4 In the process, multiple positive electrode soft tabs of multiple positive electrode sheets 10 are welded to hard electrode tabs 50, and multiple negative electrode soft tabs of multiple negative electrode sheets 20 are welded to hard electrode tabs 50. In order to save internal space of the battery, multiple positive electrode soft tabs of multiple positive electrode sheets 10 and multiple negative electrode soft tabs of multiple negative electrode sheets 20 need to be bent, so that multiple positive electrode soft tabs of multiple positive electrode sheets 10 are located in the first groove 401 and the fourth groove 404, the corresponding hard electrode tabs 50 of multiple positive electrode sheets 10 are located in the first groove 401 and the fourth groove 404, and the multiple negative electrode soft tabs of multiple negative electrode sheets 20 are located in the second groove 402 and the third groove 403, the corresponding hard electrode tabs 50 of multiple negative electrode sheets 20 are located in the second groove 402 and the third groove 403.

[0085] In one possible implementation, Figure 4 and Figure 5 In the first direction of the separator 30, the distance between the clearance portion 302 and the edge of the positive electrode 10 is W3, and the width of the stacked core structure is W4 (see...). Figure 2As shown, the ratio of W3 to W4 is greater than or equal to 3% and less than or equal to 7%. For example, the ratio of W3 to W4 can be 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, or 7%. Of course, the ratio can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the ratio of W3 to W4 is less than 3%, the distance between the clearance portion 302 and the edge of the positive electrode 10 is too small, which makes it easy for the hard electrode 50 and the positive electrode 10 to be welded together when the soft electrode tab 40 and the hard electrode tab 50 are welded together, causing damage to the positive electrode 10, resulting in electrode powder shedding and affecting the energy density. When the ratio of W3 to W4 is greater than 7%, the distance between the clearance portion 302 and the edge of the positive electrode 10 is too large, which will lead to insufficient space utilization on one side of the separator 30 in the first direction, resulting in wasted space and low energy density of the battery. In other words, by limiting the ratio between the distance between the avoidance part 302 and the edge of the positive electrode 10 and the width of the stacked core structure, it is possible to ensure that the positive electrode 10 is not damaged, while avoiding waste of internal space in the battery.

[0086] In one possible implementation, Figure 4 and Figure 5 In the thickness direction of the separator 30, the distance between the side of the clearance portion 302 away from the bottom edge 10a and the bottom edge 10a is H3, and the thickness of the stacked core structure is H4. The ratio of H3 to H4 is greater than or equal to 5% and less than or equal to 20%. For example, the ratio of H3 to H4 can be 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, or 20%. Of course, this ratio can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When the ratio of H3 to H4 is less than 5%, the distance between the side of the clearance portion 302 away from the bottom edge 10a and the bottom edge 10a is too small, resulting in a small thickness of the separator 30, causing the positive electrode 10 and the negative electrode 20 to puncture the separator 30 and short circuit. When the ratio of H3 to H4 is greater than 20%, the distance between the side of the clearance portion 302 away from the bottom edge 10a and the bottom edge 10a is too large, resulting in a large thickness of the separator 30. This causes the soft tab 40 to bend after welding the hard tab 50, leading to insufficient space utilization on one side of the separator 30 in the first direction, resulting in wasted space and low energy density of the battery. In other words, by limiting the ratio of H3 to H4, it is possible to prevent the positive electrode 10 and the negative electrode 20 from puncturing the separator 30 and causing a short circuit, while simultaneously ensuring that the internal space of the battery is not wasted.

[0087] H3 is greater than or equal to 0.1 mm and less than or equal to 0.5 mm. For example, the value of H3 can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, or 0.5 mm. Of course, this value can also be other values, and those skilled in the art can choose according to their needs. This embodiment does not limit this. When H3 is less than 0.1 mm, the distance between the side of the avoidance part 302 away from the bottom edge 10a and the bottom edge 10a is too small, resulting in a small thickness of the separator 30, causing the positive electrode 10 and the negative electrode 20 to puncture the separator 30 and short circuit. When H3 is greater than 0.5mm, the distance between the side of the clearance portion 302 away from the bottom edge 10a and the bottom edge 10a is too large, resulting in a large thickness of the separator 30. This causes the soft tab 40 to bend after welding with the hard tab 50, leading to insufficient space utilization on one side of the separator 30 in the first direction, resulting in wasted space and low energy density of the battery. In other words, by limiting H3, it is possible to prevent the positive electrode 10 and the negative electrode 20 from puncturing the separator 30 and causing a short circuit, while also ensuring that the internal space of the battery is not wasted.

[0088] In some examples, the fabrication of the stacked core structure includes the following steps:

[0089] 1. Preparation of positive electrode 10 and negative electrode 20

[0090] A positive electrode active material slurry is prepared by uniformly mixing solvent, binder, conductive agent, and positive electrode active material in a certain proportion. A negative electrode active material slurry is prepared by uniformly mixing solvent, binder, conductive agent, and negative electrode active material in a certain proportion.

[0091] It should be noted that the positive electrode active material includes at least one of lithium cobalt oxide, ternary materials, lithium iron phosphate, lithium manganese iron phosphate, and lithium-rich manganese-based materials. Ternary materials include nickel-cobalt-manganese or nickel-cobalt-aluminum. The negative electrode active material includes at least one of graphite, hard carbon, silicon-oxygen materials, and silicon-carbon.

[0092] A positive electrode active material slurry is coated onto a positive electrode current collector, and after drying, rolling, and slitting, a positive electrode sheet 10 is obtained. A negative electrode active material slurry is coated onto a negative electrode current collector, and after drying, rolling, and slitting, a negative electrode sheet 20 is obtained.

[0093] 2. The positive electrode 10 and the negative electrode 20 are cut to form two grooves respectively. A positive electrode soft tab is formed in one groove of the positive electrode 10, and a negative electrode soft tab is formed in one groove of the negative electrode 20.

[0094] 3. The positive electrode 10, separator 30 and negative electrode 20 are stacked alternately, and hot pressing is used to ensure that the stacked structure does not loosen or shake.

[0095] 4. Cut the diaphragm 30 to form a notch 301 by using a mold or laser.

[0096] 5. Bend multiple positive soft electrode tabs and multiple negative soft electrode tabs. Use ultrasonic waves, lasers, or pressure welding to thermally shrink the diaphragm 30 to form a clearance portion 302. Weld multiple positive soft electrode tabs to hard electrode tabs 50 and multiple negative soft electrode tabs to hard electrode tabs 50. Bend multiple positive soft electrode tabs into the first groove 401 and the fourth groove 404. Bend multiple negative soft electrode tabs into the second groove 402 and the third groove 403. The portion of hard electrode tab 50 corresponding to the positive soft electrode tab is located in the first groove 401 and the fourth groove 404. The portion of hard electrode tab 50 corresponding to the negative soft electrode tab is located in the second groove 402 and the third groove 403, forming a stacked core structure.

[0097] This utility model provides a battery, including a stacked core structure.

[0098] The stacked core structure in this embodiment is the same as the stacked core structure provided in any of the above embodiments, and can bring the same or similar technical effects. It will not be described in detail here, but can be referred to the description of the above embodiments.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A core stack structure, characterized by, The positive electrode sheet (10), the separator (30) and the negative electrode sheet (20) are alternately laminated to form the core structure; The positive electrode sheet (10) is provided with a first groove (401) and a second groove (402) on one side of the first direction of the separator (30), the negative electrode sheet (20) is provided with a third groove (403) and a fourth groove (404) on one side of the first direction of the separator (30), the first groove (401) corresponds to the fourth groove (404) in the thickness direction of the separator (30), the second groove (402) corresponds to the third groove (403) in the thickness direction of the separator (30), and the first groove (401) and the third groove (403) are both formed with a soft tab (40), the soft tab (40) includes a positive soft tab in the first groove (401) and a negative soft tab in the third groove (403); In the length direction of the separator (30), each of the separators (30) is provided with a cutout (301) on both sides of the position corresponding to the soft tab (40), and the length L1 of the cutout (301) is less than the length S3 of the third groove (403); The ratio of the length L1 of the cutout (301) to the length S3 of the third groove (403) is 80%-95%.

2. The core structure of claim 1, wherein In the first direction of the separator (30), the length of the first groove (401) is S1, the length of the second groove (402) is S2, the length of the third groove (403) is S3, and the length of the fourth groove (404) is S4; S3 satisfies: S3 < S2; and / or, S4 satisfies: S4 < S1.

3. The core structure of claim 1, wherein In the length direction of the separator (30), the distance between the two cutouts (301) corresponding to the positive soft tab and the negative soft tab is Q1, the distance between the cutout (301) and the welding mark (405) is Q2, the width of the hard tab (50) is T, and Q2 satisfies: Q2 = (Q1-T) / 2+b, wherein b is less than 0.35mm; and / or, Q2 satisfies: Q2 = (Q1-T) / 2-b, wherein b is less than 0.35mm; and / or, Q1 is greater than or equal to 4mm and less than or equal to 15mm.

4. The core structure of claim 3, wherein In the length direction of the separator (30), the length of the core structure is L2, the ratio of Q2 to L2 is greater than or equal to 0.2% and less than or equal to 3%, and / or each positive soft tab and each negative soft tab is welded with a hard tab (50) to form a welding mark (405), and the projection of the welding mark (405) in the thickness direction of the positive electrode sheet (10) and the projection of the separator (30) do not overlap.

5. The core structure according to any one of claims 1 to 4, wherein At least one of the diaphragms (30) is provided with a relief portion (302) located between two adjacent cutouts (301), and the relief portion (302) and a welding mark (405) form a relief area.

6. The core structure of claim 5, wherein The diaphragm (30) comprises a body (30a) connected to the relief portion (302), and a ratio of a thickness of the relief portion (302) to a thickness of the body (30a) in a thickness direction of the diaphragm (30) is greater than or equal to 1.02 and less than or equal to 1.

1.

7. The core structure of claim 6, wherein In a first direction of the diaphragm (30), an end of the relief portion (302) away from the welding mark (405) is a first end, an end of the diaphragm (30) close to the welding mark (405) is a second end, a distance between the first end and the second end is L3, a distance between the first end and the welding mark (405) is W1, a ratio of the L3 to the W1 is greater than or equal to 0.1 and less than or equal to 0.95; and / or, In the first direction of the diaphragm (30), a distance between the relief portion (302) and an edge of the positive plate (10) is W3, a width of the core structure is W4, a ratio of the W3 to the W4 is greater than or equal to 3% and less than or equal to 7%.

8. The core structure of claim 6, wherein In a length direction of the diaphragm (30), a width of the relief portion (302) is L4, a width of the welding mark (405) is W2, a ratio of the L4 to the W2 is greater than or equal to 0.8 and less than or equal to 1.

2.

9. The core structure of claim 6, wherein In the thickness direction of the diaphragm (30), the core structure has oppositely arranged bottom edges (10a) and top edges (10b), a distance between a side of the relief portion (302) away from the bottom edges (10a) and the bottom edges (10a) is H3, a thickness of the core structure is H4, a ratio of the H3 to the H4 is greater than or equal to 5% and less than or equal to 20%; and / or, The H3 is greater than or equal to 0.1 mm and less than or equal to 0.5 mm.

10. A battery, characterized by The core structure comprises the diaphragm (30) according to any one of claims 1-9. The core structure comprises the diaphragm (30) according to any one of claims 1-9.

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