Cells and Batteries

Abstract

The utility model relates to the technical field of lithium-ion batteries, and in particular to a battery cell and a battery. The battery cell comprises a first current collector, a second current collector, a first diaphragm and a second diaphragm, the polarity of the second current collector is opposite to that of the first current collector, the second current collector is staggered and arranged on one side of the first current collector, the first diaphragm is arranged between the first current collector and the second current collector, and the second diaphragm is arranged on the side of the first current collector away from the first diaphragm, wherein, at the winding start end of the battery cell, the end of the first diaphragm exceeds the end of the first current collector to form a first extension end, and the end of the second diaphragm exceeds the end of the first current collector to form a second extension end, the first extension end and the second extension end are both straight sections, and the length L1 of the first extension end satisfies: 5mm≤L1≤10mm, and the length L2 of the second extension end satisfies: 5mm≤L2≤10mm. The battery comprises the above-mentioned battery cell. The diaphragm in the battery cell and the battery cancels pre-rolling, so that the overall energy density is high.

Description

Technical Field

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

[0002] Lithium-ion battery is a secondary battery, which consists of an internal bare cell and an outer shell. The internal bare cell is mainly composed of a positive electrode sheet, a negative electrode sheet and a separator film, which are wound together. The separator film is arranged between the positive electrode sheet and the negative electrode sheet. The positive and negative electrode surfaces are coated with active substances to participate in charging and discharging. In order to prevent the bare cell winding head electrode sheet from wrinkling and folding, a 1.5-turn separator film pre-roll is usually arranged at the winding starting end of the electrode sheet. As the market's requirements for the energy density of the battery cell become higher and higher, the pre-rolled separator film at the head has an increasingly significant impact on the thickness of the battery cell. While affecting the thickness and flatness of the battery cell, a large amount of separator film is also wasted, resulting in a waste of raw material costs. Utility Model Content

[0003] The main purpose of the utility model is to provide a battery cell and a battery, aiming to solve the technical problem that the pre-rolled isolation film at the head of the existing battery cell thickens the overall thickness of the battery cell, resulting in a decrease in the energy density of the battery cell and a waste of isolation film materials.

[0004] In order to achieve the above object, the utility model proposes a battery cell, comprising:

[0005] First Collector Fluid;

[0006] a second current collector, wherein the polarity of the second current collector is opposite to that of the first current collector, and the second current collector is staggered and disposed on one side of the first current collector;

[0007] a first diaphragm, the first diaphragm being disposed between the first current collector and the second current collector;

[0008] a second diaphragm, the second diaphragm being disposed on a side of the first current collector facing away from the first diaphragm;

[0009] Among them, at the starting end of the winding of the battery cell, the end of the first current collector exceeds the end of the second current collector, the end of the first diaphragm exceeds the end of the first current collector to form a first extended end, and the end of the second diaphragm exceeds the end of the first current collector to form a second extended end, the first extended end and the second extended end are both straight sections, the length L1 of the first extended end satisfies: 5mm≤L1≤10mm, and the length L2 of the second extended end satisfies: 5mm≤L2≤10mm.

[0010] In some embodiments, at the starting end of the winding of the battery cell, a first adhesive tape is provided on the end of the first current collector close to the first diaphragm, and the first adhesive tape extends out of the end of the first current collector to form a third extended end, and the third extended end is bonded together with the first extended end and the second extended end.

[0011] In some embodiments, at the starting end of the winding of the battery cell, a second adhesive tape is provided on the end of the second current collector close to the first diaphragm, and the second adhesive tape extends out of the end of the second current collector to form a fourth extended end, and the fourth extended end is bonded to the first diaphragm and the second diaphragm.

[0012] In some embodiments, an end of the first adhesive tape facing away from the third protruding end overlaps with the fourth protruding end.

[0013] In some embodiments, at the starting end of the winding of the battery cell, a first adhesive layer is provided at the end of the second current collector, and the first adhesive layer is bonded to the first separator and the second separator to bond the second current collector and the first separator and the second separator together.

[0014] In some embodiments, the first adhesive layer is a non-conductive structure.

[0015] In some embodiments, an end of the first protruding end and an end of the second protruding end are bonded together by a second adhesive layer, so that the first diaphragm and the second diaphragm are bonded together.

[0016] In some embodiments, the first current collector is a negative electrode current collector, and the second current collector is a positive electrode current collector.

[0017] In some embodiments, the length L3 of the third protruding end satisfies: 1mm≤L3≤2mm, and the length L4 of the fourth protruding end satisfies: 1mm≤L4≤2mm.

[0018] In some embodiments, at the starting end of the winding of the battery cell, a third tape is provided at the end of the first current collector close to the second diaphragm, and the third tape extends out of the end of the first current collector, and a fourth tape is provided at the end of the second current collector away from the first diaphragm, and the fourth tape extends out of the end of the second current collector.

[0019] In some embodiments, at the starting end of winding of the battery cell, the distance L5 between the end of the first separator and the inner corner of the battery cell satisfies: L5≥2mm, and the distance L6 between the end of the second separator and the inner corner of the battery cell satisfies: L6≥2mm.

[0020] In some embodiments, the thickness D1 of the first diaphragm satisfies: 5um≤D1≤30um, and the thickness D2 of the second diaphragm satisfies: 5um≤D2≤30um.

[0021] In some embodiments, the length L1 of the first protruding end and the length L2 of the second protruding end satisfy: L1 = L2.

[0022] Correspondingly, the utility model also proposes a battery, comprising the battery cell described in any one of the above items.

[0023] Compared with the prior art, the beneficial effects of the utility model are:

[0024] In the technical solution of the utility model, the battery cell cancels the half-circle pre-rolled isolation film set at the starting end of the winding, and only extends the first separator and the second separator outward, so that the length of the first separator and the second separator exceeds the first current collector by 5mm to 10mm (including the end value), and the first current collector and the second current collector are separated. In this way, even if the head of the first separator and the second separator shrinks due to factors such as heating, charging and discharging of the battery cell, since the first separator has a first protruding end exceeding the end of the first current collector and the second separator has a second protruding end exceeding the end of the first current collector, the first separator and the second separator have room to shrink. Even if the first separator and the second separator shrink, they can still cover the current collector to prevent the current collector from leaking and causing a contact short circuit. At the same time, since the first current collector, the second current collector, the first diaphragm and the second diaphragm at the starting end of the winding of the battery cell are all on the same straight line, compared with pre-winding a half-circle of the isolation film at the starting end of the winding of the battery cell, the overall thickness of the battery cell provided by the utility model is thinner, thereby effectively improving the energy density of the battery cell, while also saving material usage and reducing production costs.

[0025] The battery using the above-mentioned cell is helpful to reduce the volume of the battery and improve the energy density of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the overall structure of a battery cell provided in one embodiment of the utility model;

[0028] Figure 2 A schematic diagram of the overall structure of a battery cell provided in another embodiment of the utility model;

[0029] Figure 3 A schematic diagram of the overall structure of a battery cell provided in another embodiment of the utility model;

[0030] Figure 4 A schematic diagram of the overall structure of a battery cell provided in yet another embodiment of the utility model;

[0031] Figure 5 A schematic diagram of the overall structure of a battery cell provided in yet another embodiment of the utility model;

[0032] Figure 6 A schematic diagram of the relative position relationship between the current collector, the separator and the adhesive tape in a battery cell provided by another embodiment of the utility model;

[0033] Figure 7 A schematic structural diagram of a winding start end of a battery cell provided in yet another embodiment of the present invention.

[0034] Description of Figure Numbers:

[0035] 100-first current collector;

[0036] 200-second collector;

[0037] 300-first diaphragm;

[0038] 310-first extension end;

[0039] 400 - second diaphragm;

[0040] 410 - second extension end;

[0041] 500-first adhesive tape;

[0042] 510 - third extension end;

[0043] 600-second adhesive tape;

[0044] 610- fourth extension end;

[0045] 700-first adhesive layer;

[0046] 800-second adhesive layer;

[0047] 900-third adhesive tape;

[0048] 1000-Fourth adhesive tape.

[0049] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0051] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0052] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or", "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0053] Lithium-ion battery is a secondary battery, which consists of an internal bare cell and an outer shell. The internal bare cell is mainly composed of a positive electrode sheet, a negative electrode sheet and a separator film, which are wound together. The separator film is arranged between the positive electrode sheet and the negative electrode sheet. The positive and negative electrode surfaces are coated with active substances to participate in charging and discharging. In order to prevent the bare cell winding head electrode sheet from wrinkling and folding, a 1.5-turn separator film pre-roll is usually arranged at the winding starting end of the electrode sheet. As the market's requirements for the energy density of the battery cell become higher and higher, the pre-rolled separator film at the head has an increasingly significant impact on the thickness of the battery cell. While affecting the thickness and flatness of the battery cell, a large amount of separator film is also wasted, resulting in a waste of raw material costs.

[0054] In order to solve the technical problem that the pre-rolled isolation film at the head of the existing battery cell thickens the overall thickness of the battery cell, resulting in a decrease in the energy density of the battery cell and a waste of isolation film materials, reference is made to Figure 1 and Figure 7, an embodiment of the utility model provides a battery cell, including a first current collector 100, a second current collector 200, a first separator 300 and a second separator 400, the polarity of the second current collector 200 is opposite to the polarity of the first current collector 100, illustratively, for example, if the first current collector 100 is a negative electrode current collector, the second current collector 200 is a positive electrode current collector, similarly, if the first current collector 100 is a positive electrode current collector, the second current collector 200 is a negative electrode current collector, and the second current collector 200 is staggered and arranged on one side of the first current collector 100, that is, the head ends of the first current collector 100 and the second current collector 200 are not aligned, and usually, the negative electrode current collector The end portion should extend beyond the end portion of the positive electrode collector to prevent lithium ions from precipitating on the surface of the negative electrode when the battery is charged, forming lithium dendrites, piercing the diaphragm, causing a short circuit in the battery, and thus causing thermal runaway. The first diaphragm 300 is disposed between the first current collector 100 and the second current collector 200 to separate the first current collector 100 and the second current collector 200 to prevent the first current collector 100 and the second current collector 200 from directly contacting each other and causing a short circuit in the battery. The second diaphragm 400 is disposed on the side of the first current collector 100 away from the first diaphragm 300 to prevent the current collectors from directly contacting each other when the battery cell is wound and causing a short circuit in the battery. Among them, at the winding start end of the battery cell, the end of the first current collector 100 exceeds the end of the second current collector 200, the end of the first diaphragm 300 exceeds the end of the first current collector 100, forming a first extended end 310, and the end of the second diaphragm 400 exceeds the end of the first current collector 100, forming a second extended end 410, the first extended end 310 and the second extended end 410 are both straight sections, and the length L1 of the first extended end 310 satisfies: 5mm≤L1≤10mm, and the length L2 of the second extended end 410 satisfies: 5mm≤L2≤10mm. Exemplarily, for example, the value of L1 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc., and the value of L2 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. It is understandable that L1 and L2 can take the same value, for example, the values ​​of L1 and L2 are both 8 mm, or L1 and L2 can take different values, for example, the value of L1 can be 8 mm, and the value of L2 can be 6 mm.

[0055] Specifically, in the present embodiment, the battery cell cancels the half-turn pre-rolled isolation film provided at the starting end of the winding, and only extends the first separator 300 and the second separator 400 outward, so that the length of the first separator 300 and the second separator 400 exceeds the first current collector 100 by 5 mm to 10 mm (including the end value), and the first current collector 100 and the second current collector 200 are separated. In this way, even if the head of the first separator 300 and the second separator 400 shrink due to factors such as heating, charging and discharging of the battery cell, since the first separator 300 has a first protruding end 310 that exceeds the end of the first current collector 100, and the second separator 400 has a second protruding end 410 that exceeds the end of the first current collector 100, the first separator 300 and the second separator 400 have room to shrink. Even if the first separator 300 and the second separator 400 shrink, they can still cover the current collector to prevent the current collector from leaking and causing a contact short circuit. At the same time, since the first current collector 100, the second current collector 200, the first separator 300 and the second separator 400 at the starting end of the winding of the battery cell are all on the same straight line, compared with pre-winding a half-turn of the isolation film at the starting end of the winding of the battery cell, the overall thickness of the battery cell provided in this embodiment is thinner, thereby effectively improving the energy density of the battery cell, while also saving material usage and reducing production costs.

[0056] In some embodiments, reference Figure 2 At the starting end of the winding of the battery cell, a first adhesive tape 500 is provided at the end of the first current collector 100 close to the first separator 300. The first adhesive tape 500 extends out of the end of the first current collector 100 to form a third extended end 510. The third extended end 510 is bonded together with the first extended end 310 and the second extended end 410.

[0057] Specifically, in this embodiment, since the first adhesive tape 500 is sticky, the third extension end 510 can be bonded together with the first extension end 310 and the second extension end 410, so that the first adhesive tape 500 can be effectively used to fix the first diaphragm 300 and the second diaphragm 400 at the first current collector 100, prevent the first diaphragm 300 and the second diaphragm 400 at the first current collector 100 from shrinking, ensure that the first diaphragm 300 and the second diaphragm 400 always cover the current collector, improve the safety of the battery cell, and reduce the risk of short circuit in the battery cell.

[0058] Since it is necessary to prevent the edge burrs of the positive electrode ear or the negative electrode ear from scratching the diaphragm, thereby causing direct contact between the first current collector 100 and the second current collector 200 and causing a short circuit in the battery cell, protective tape is pasted on the positive electrode ear and the negative electrode ear. Therefore, in some embodiments, the length of the first tape 500 at the first electrode ear can be increased and extended outward to form a third protruding end 510. This helps to reduce the process steps of battery cell processing and simplifies the process flow of battery cell manufacturing.

[0059] More preferably, while increasing the length of the first adhesive tape 500, the width of the first adhesive tape 500 can also be increased, so that the bonding between the first adhesive tape 500 and the first diaphragm 300 and the second diaphragm 400 at the first current collector 100 is more firmly, and the first adhesive tape 500 can be more effectively used to fix the first diaphragm 300 and the second diaphragm 400 at the first current collector 100, thereby reducing the risk of shrinkage of the first diaphragm 300 and the second diaphragm 400 at the first current collector 100.

[0060] In some embodiments, reference Figure 2 At the starting end of the winding of the battery cell, a second adhesive tape 600 is provided at the end of the second current collector 200 close to the first separator 300. The second adhesive tape 600 extends out of the end of the second current collector 200 to form a fourth extended end 610. The fourth extended end 610 is bonded together with the first separator 300 and the second separator 400.

[0061] Specifically, in this embodiment, since the second adhesive tape 600 is sticky, the fourth protruding end 610 can be bonded together with the first diaphragm 300 and the second diaphragm 400, so that the second adhesive tape 600 can be effectively used to fix the first diaphragm 300 and the second diaphragm 400 at the second current collector 200, preventing the first diaphragm 300 and the second diaphragm 400 at the second current collector 200 from shrinking, thereby providing double protection for the diaphragm covering the current collector.

[0062] More preferably, referring to the above embodiment, in some embodiments, the length of the second adhesive tape 600 at the second pole ear can be increased, and the second adhesive tape 600 can be extended outward to form a fourth extension end 610, which is conducive to reducing the process steps of the battery cell processing and simplifying the process flow of making the battery cell. In addition, while increasing the length of the second adhesive tape 600, the width of the second adhesive tape 600 can also be increased, so that the second adhesive tape 600 and the first diaphragm 300 and the second diaphragm 400 at the second current collector 200 are more firmly bonded, and the second adhesive tape 600 is more effectively used to fix the first diaphragm 300 and the second diaphragm 400 at the second current collector 200, reducing the risk of the first diaphragm 300 and the second diaphragm 400 at the second current collector 200 shrinking.

[0063] In some embodiments, reference Figure 2 , an end of the first adhesive tape 500 away from the third extension end 510 is overlapped with the fourth extension end 610 .

[0064] Specifically, in this embodiment, since the first current collector 100 and the second current collector 200 are separated by the first diaphragm 300, when the first diaphragm 300 shrinks, it will directly cause the first current collector 100 and the second current collector 200 to contact each other. Therefore, in order to avoid the situation that the first current collector 100 and the second current collector 200 directly contact each other and cause a short circuit in the battery cell, while ensuring that the first adhesive tape 500 extends out of the end of the first current collector 100 and the second adhesive tape 600 extends out of the end of the second current collector 200, the first adhesive tape 500 can be appropriately increased. 00 and the second tape 600 have a relative length such that the first tape 500 and the second tape 600 overlap each other. In this way, even when the first diaphragm 300 shrinks severely, the first tape 500 and the second tape 600 are in contact with each other, and the first current collector 100 will not contact the second current collector 200. Since the first tape 500 and the second tape 600 are insulated, even if the first tape 500 and the second tape 600 are in contact with each other, a short circuit will not occur inside the battery cell, thereby ensuring the safety performance of the battery cell.

[0065] In some embodiments, reference Figure 3 At the starting end of the winding of the battery cell, a first adhesive layer 700 is provided at the end of the second current collector 200, and the first adhesive layer 700 is bonded to the first separator 300 and the second separator 400, so that the second current collector 200 and the first separator 300 and the second separator 400 are bonded together.

[0066] Specifically, in this embodiment, referring to the above embodiment, the bonding method of bonding the second current collector 200, the first diaphragm 300 and the second diaphragm 400 together by using the second adhesive tape 600 in the above embodiment can be replaced by bonding the second current collector 200, the first diaphragm 300 and the second diaphragm 400 together by using the first adhesive layer 700. Since the adhesion of the first adhesive layer 700 is stronger, the bonding between the second current collector 200 and the first diaphragm 300 and the second diaphragm 400 is more firmly, even under the influence of factors such as charging and discharging and heating of the battery cell, the first diaphragm 300 and the second diaphragm 400 are still stronger than the first diaphragm 300. No shrinkage will occur at the second current collector 200. In this way, even if the first diaphragm 300 and the second diaphragm 400 shrink at the first current collector 100 and cause the first current collector 100 to leak, due to the effect of the first adhesive layer, the first diaphragm 300 and the second diaphragm 400 will not continue to shrink at the second current collector 200, and the first diaphragm 300 and the second diaphragm 400 can be ensured to always cover between the first current collector 100 and the second current collector 200, so that the first current collector 100 and the second current collector 200 will not be in direct contact, thereby effectively avoiding a short circuit in the battery cell and ensuring the safety performance of the battery cell.

[0067] In some embodiments, the first adhesive layer 700 is a non-conductive structure. For example, the first adhesive layer 700 may be a double-sided adhesive, so that the first separator 300 and the second separator 400 may be bonded simultaneously by the first adhesive layer 700. Since the first adhesive layer 700 is non-conductive, even if the first current collector 100 is exposed and contacts the first adhesive layer 700, a short circuit will not occur inside the battery cell.

[0068] In some embodiments, reference Figure 4 The end of the first extension end 310 and the end of the second extension end 410 are bonded together by the second adhesive layer 800, so that the first diaphragm 300 and the second diaphragm 400 are bonded together.

[0069] Specifically, in the present embodiment, in order to further prevent the first diaphragm 300 and the second diaphragm 400 from shrinking, the first diaphragm 300 and the second diaphragm 400 can be bonded and fixed by the second adhesive layer 800, so that the first diaphragm 300 and the second diaphragm 400 are combined together. With this structure, the first diaphragm 300 and the second diaphragm 400 can be fundamentally prevented from shrinking. In the above structure, the first current collector 100 is completely covered between the first diaphragm 300 and the second diaphragm 400. Since the first diaphragm 300 and the second diaphragm 400 will not shrink, the first current collector 100 will not leak, and the first current collector 100 cannot directly contact the second current collector 200 to cause a short circuit in the battery cell.

[0070] Furthermore, the size of the second adhesive layer 800 can be appropriately increased so that the second adhesive layer 800 is not only bonded to the winding head ends of the first diaphragm 300 and the second diaphragm 400, but also bonded to the inner side of the winding circle of the diaphragm, that is, the second adhesive layer 800 is used to fill the space between the winding head end of the diaphragm and the inner side of the winding circle of the diaphragm. In this way, the winding head ends of the first diaphragm 300 and the second diaphragm 400 can be more effectively fixed, thereby improving the bonding integrity of the second adhesive layer 800.

[0071] It can be understood that the second adhesive layer 800 is also a non-conductive structure.

[0072] In some embodiments, the first current collector 100 is a negative electrode current collector, and the second current collector 200 is a positive electrode current collector.

[0073] Specifically, in the present embodiment, at the starting end of the winding of the battery cell, the end of the negative electrode current collector will exceed the end of the positive electrode current collector, realizing the "anode wrapped in cathode" of the battery cell, and the ends of the first separator 300 and the second separator 400 will exceed the end of the longer negative electrode current collector. With such a structure, even if the first separator 300 and the second separator 400 shrink, so that the head of the negative electrode current collector is exposed, the positive electrode current collector is still covered between the first separator 300 and the second separator 400, and the negative electrode current collector and the positive electrode current collector will not be in direct contact, and a short circuit will not occur inside the battery cell.

[0074] In some embodiments, reference Figure 7 , the length L3 of the third extension end 510 satisfies: 1mm≤L3≤2mm, and the length L4 of the fourth extension end 610 satisfies: 1mm≤L4≤2mm. Exemplarily, for example, the value of L3 can be 1mm, 1.3mm, 1.5mm, 1.7mm, 2mm, etc., and the value of L4 can be 1mm, 1.3mm, 1.5mm, 1.7mm, 2mm, etc.

[0075] Specifically, in the present embodiment, since only the diaphragm will shrink after the battery cell is charged and discharged and affected by heat, and the adhesive tape will not shrink, the first adhesive tape 500 only needs to cover the position of the winding head end of the first current collector 100 and stick to the first protruding end 310 and the second protruding end 410. The second adhesive tape 600 only needs to cover the position of the winding head end of the second current collector 200 and stick to the first diaphragm 300 and the second diaphragm 400. There is no need to set the length of the third protruding end 510 of the first adhesive tape 500 and the fourth protruding end 610 of the second adhesive tape 600 to be very long. The length of the third protruding end 510 and the fourth protruding end 610 can be between 1 mm and 2 mm, thereby avoiding the waste of raw materials of the first adhesive tape 500 and the second adhesive tape 600, which is in line with the concept of economy and environmental protection.

[0076] In some embodiments, reference Figures 5 and 6 At the starting end of the winding of the battery cell, a third tape 900 is provided at the end of the first current collector 100 close to the second separator 400, and the third tape 900 extends out of the end of the first current collector 100, and a fourth tape 1000 is provided at the end of the second current collector 200 away from the first separator 300, and the fourth tape 1000 extends out of the end of the second current collector 200.

[0077] Specifically, in order to further improve the safety of battery cells and prevent short circuits within the battery cells, in this embodiment, by affixing adhesive tape on both sides of the first current collector 100 and both sides of the second current collector 200, it is possible to effectively prevent burrs on the end from piercing the first diaphragm 300 or the second diaphragm 400, resulting in direct contact between the first current collector 100 and the second current collector 200, thereby causing a short circuit within the battery cell.

[0078] In some embodiments, reference Figure 7 , at the winding start end of the battery cell, the distance L5 between the end of the first separator 300 and the inner corner of the battery cell satisfies: L5 ≥ 2mm, and the distance L6 between the end of the second separator 400 and the inner corner of the battery cell satisfies: L6 ≥ 2mm. Exemplarily, for example, the value of L5 can be 2mm, 2.5mm, 3mm, 4mm, 5mm, etc., and the value of L6 can be 2mm, 2.5mm, 3mm, 4mm, 5mm, etc.

[0079] Specifically, in order to prevent the electrode or diaphragm at the head of the battery cell from wrinkling or folding and to ensure the flatness of the battery cell during winding, in the present embodiment, there needs to be a certain distance between the end of the first diaphragm 300 and the end of the second diaphragm 400 and the inner corner of the battery cell to prevent the end of the first diaphragm 300 and the second diaphragm 400 from hitting the inner corner of the battery cell, causing the first diaphragm 300 and the second diaphragm 400 to wrinkle when the battery cell is wound, thereby affecting the safety of the battery cell.

[0080] In some embodiments, the thickness D1 of the first diaphragm 300 satisfies: 5um≤D1≤30um, and the thickness D2 of the second diaphragm 400 satisfies: 5um≤D2≤30um. Exemplarily, for example, the value of D1 can be 5um, 10um, 15um, 20um, 25um, 30um, etc., and the value of D2 can be 5um, 10um, 15um, 20um, 25um, 30um, etc. It should be noted that D1 and D2 can take the same value, D1 and D2 can also take different values, and the thickness design of the first diaphragm 300 and the second diaphragm 400 can be adaptively set according to the actual production requirements of the battery cell.

[0081] Specifically, in order to ensure the design safety of the battery cell and to ensure the overall energy density of the battery cell, in the present embodiment, the thickness of the first diaphragm 300 and the thickness of the second diaphragm 400 are limited to a specific numerical range. If the thickness of the first diaphragm 300 and the thickness of the second diaphragm 400 are designed to be too thin, that is, D1 < 5um, D2 < 5um, the first diaphragm 300 and the second diaphragm 400 cannot play a good isolation role, which may easily lead to a short circuit in the battery cell, posing a safety risk to the battery cell. If the thickness of the first diaphragm 300 and the second diaphragm 400 are designed to be too thick, that is, D1 > 30um, D2 > 30um, the overall thickness of the battery cell will be increased, resulting in a decrease in the overall energy density of the battery cell.

[0082] In some embodiments, reference Figure 7 , the length L1 of the first extending end 310 and the length L2 of the second extending end 410 satisfy: L1 = L2.

[0083] Specifically, in order to simplify the process of battery cell production and improve the efficiency of battery cell production, in the present embodiment, the first extension end 310 and the second extension end 410 are designed to be equal in length, that is, L1 and L2 take equal values. Exemplarily, for example, L1 and L2 can both take 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. Before the battery cell is wound, the first diaphragm 300 and the second diaphragm 400 are cut together, and it is ensured that the ends of the first diaphragm 300 and the second diaphragm 400 are cut flush to form the first extension end 310 and the second extension end 410. With such a structure, when producing battery cells, the ends of the first diaphragm 300 and the second diaphragm 400 can be "cut with one knife", thereby simplifying the process of battery cell production and improving the efficiency of battery cell production.

[0084] It should be noted that the battery cell may adopt only one structural form of any of the above embodiments. For example, at the start of winding of the battery cell, only the end of the first separator 300 may extend beyond the end of the first current collector 100, and the portion of the end of the first separator 300 extending beyond the end of the first current collector 100 is a straight section, that is, the portion extending beyond the end of the first current collector 100 is not pre-rolled, and the end of the second separator 400 may extend beyond the end of the first current collector 100, and the portion of the end of the second separator 400 extending beyond the end of the first current collector 100 is a straight section, that is, the portion extending beyond the end of the first current collector 100 is not pre-rolled. The battery cell may also adopt any combination of structural forms of the above embodiments. For example, at the start of winding of the battery cell, the end of the first separator 300 extends beyond the end of the first current collector 100, and the end of the second separator 400 extends beyond the end of the first current collector 100, and the extended ends of the first separator 300 and the second separator 400 may be bonded together using an adhesive layer.

[0085] Correspondingly, another embodiment of the present invention further provides a battery, which includes the battery cell in any of the above embodiments.

[0086] Specifically, in this embodiment, the battery can be a lithium-ion battery. The battery using the battery cell in the above embodiment is beneficial to reducing the volume of the battery and improving the energy density of the battery. Thanks to the improvement of the above battery cell, the battery in this embodiment has the same technical effect as the above battery cell, which will not be described in detail here.

[0087] It should be noted that other contents of the battery cell and battery disclosed in the present utility model can be found in the prior art and will not be described in detail here.

[0088] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A battery cell, characterized in that: include: First Collector Fluid; a second current collector, wherein the polarity of the second current collector is opposite to that of the first current collector, and the second current collector is staggered and disposed on one side of the first current collector; a first diaphragm, the first diaphragm being disposed between the first current collector and the second current collector; a second diaphragm, the second diaphragm being disposed on a side of the first current collector facing away from the first diaphragm; Among them, at the starting end of the winding of the battery cell, the end of the first current collector exceeds the end of the second current collector, the end of the first diaphragm exceeds the end of the first current collector to form a first extended end, and the end of the second diaphragm exceeds the end of the first current collector to form a second extended end, the first extended end and the second extended end are both straight sections, the length L1 of the first extended end satisfies: 5mm≤L1≤10mm, and the length L2 of the second extended end satisfies: 5mm≤L2≤10mm.

2. The battery cell according to claim 1, characterized in that: At the starting end of the winding of the battery cell, a first adhesive tape is provided at the end of the first current collector close to the first diaphragm, and the first adhesive tape extends out of the end of the first current collector to form a third extended end, and the third extended end is bonded together with the first extended end and the second extended end.

3. The battery cell according to claim 2, characterized in that: At the starting end of the winding of the battery cell, a second adhesive tape is provided on the end of the second current collector close to the first separator, and the second adhesive tape extends out of the end of the second current collector to form a fourth extended end, and the fourth extended end is bonded to the first separator and the second separator.

4. The battery cell according to claim 3, characterized in that: One end of the first adhesive tape away from the third extending end is overlapped with the fourth extending end.

5. The battery cell according to claim 2, characterized in that: At the winding start end of the battery cell, a first adhesive layer is provided at the end of the second current collector, and the first adhesive layer is bonded to the first separator and the second separator, so that the second current collector and the first separator and the second separator are bonded together.

6. The battery cell according to claim 5, characterized in that: The first adhesive layer is a non-conductive structure.

7. The battery cell according to claim 1, characterized in that: The end of the first protruding end and the end of the second protruding end are bonded together by a second adhesive layer, so that the first diaphragm and the second diaphragm are bonded together.

8. The battery cell according to any one of claims 1 to 7, characterized in that: The first current collector is a negative electrode current collector, and the second current collector is a positive electrode current collector.

9. The battery cell according to claim 3, characterized in that: The length L3 of the third extending end satisfies: 1mm≤L3≤2mm, and the length L4 of the fourth extending end satisfies: 1mm≤L4≤2mm.

10. The battery cell according to claim 1, characterized in that: At the starting end of the winding of the battery cell, a third tape is provided at the end of the first current collector close to the second diaphragm, and the third tape extends out of the end of the first current collector. A fourth tape is provided at the end of the second current collector away from the first diaphragm, and the fourth tape extends out of the end of the second current collector.

11. The battery cell according to claim 1, characterized in that: At the winding starting end of the battery cell, a distance L5 between an end of the first separator and an inner corner of the battery cell satisfies: L5≥2mm, and a distance L6 between an end of the second separator and an inner corner of the battery cell satisfies: L6≥2mm.

12. The battery cell according to claim 1, characterized in that: The thickness D1 of the first diaphragm satisfies: 5um≤D1≤30um, and the thickness D2 of the second diaphragm satisfies: 5um≤D2≤30um.

13. The battery cell according to claim 1, characterized in that: The length L1 of the first extended end and the length L2 of the second extended end satisfy: L1 = L2.

14. A battery, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 13.

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