Cells, Batteries and Electronic Devices

Abstract

The utility model relates to the technical field of batteries, and in particular to a battery cell, a battery and an electronic device. The battery cell comprises a first current collector and a second current collector, the first current collector having a first terminal, a first empty foil area is arranged on a side of the first current collector close to the first terminal, the first empty foil area is used to weld a first pole ear, a first adhesive tape is arranged at the first pole ear, the second current collector having a second terminal, a second empty foil area is arranged on a side of the second current collector close to the second terminal, the second empty foil area is used to weld a second pole ear, the first pole ear is arranged on a side of the first current collector away from the first terminal, the second pole ear is arranged close to the first pole ear, between the first adhesive tape and the first terminal, a first active material layer is arranged on the surface of the first current collector, and a second active material layer is arranged on the surface of the second current collector corresponding to the first active material layer. The battery comprises the above-mentioned battery cell. The electronic device comprises the above-mentioned battery. The battery cell, battery and electronic device have high energy density.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery cell, a battery and an electronic device. Background Art

[0002] Lithium-ion battery is a secondary battery, which consists of an internal bare cell and a 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 materials to participate in charging and discharging. In the head area of ​​the positive and negative electrode sheets, a section of the current collector is reserved without coating the active material layer for welding the pole ears. As the market's requirements for the energy density of the battery cell become higher and higher, the longer section of the empty foil area reserved at the head of the current collector fails to effectively exert the charging and discharging performance, resulting in low space utilization inside the battery cell, thereby reducing the energy density of the battery cell. Utility Model Content

[0003] The main purpose of the utility model is to provide a battery cell, a battery and an electronic device, aiming to solve the technical problems of low space utilization inside the battery cell caused by the empty foil area reserved at the head of the current collector and low energy density of the battery cell.

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

[0005] A first current collector, wherein the first current collector has a first end portion, a first empty foil area is disposed on a side of the first current collector close to the first end portion, the first empty foil area is used for welding a first electrode tab, and a first adhesive tape is disposed at the first electrode tab;

[0006] A second current collector, wherein the polarity of the second current collector is opposite to that of the first current collector, the second current collector has a second end portion, the second end portion exceeds the first end portion, a second empty foil area is provided on a side of the second current collector close to the second end portion, the second empty foil area is used for welding a second electrode tab, and a second adhesive tape is provided at the second electrode tab;

[0007] Among them, the first pole ear is arranged on the side of the first current collector away from the first end head, and the second pole ear is arranged close to the first pole ear, so that the distance L1 between the first pole ear and the second pole ear satisfies: 6mm≤L1≤10mm; between the end of the first adhesive tape close to the first end head and the first end head, a first active material layer is arranged on the surface of the first current collector; between the end of the second adhesive tape close to the second end head and the second end head, a second active material layer is arranged on the surface of the second current collector, and the first active material layer and the second active material layer are arranged opposite to each other.

[0008] In some embodiments, between one end of the first tape close to the first end head and the first end head, the first active material layer coated relatively is provided on both side surfaces of the first current collector; relative to the first active material layer, the second active material layer is provided on the surface of the second current collector.

[0009] In some embodiments, both ends of the second active material layer extend beyond both ends of the first active material layer, so that one end of the second active material layer forms a first extending portion, and the other end of the second active material layer forms a second extending portion.

[0010] In some embodiments, the length L2 of the first protruding portion satisfies: L2 ≥ 2 mm, and the length L3 of the second protruding portion satisfies: L3 ≥ 2 mm.

[0011] In some embodiments, a first diaphragm is disposed between the first current collector and the second current collector, the first diaphragm has a third end portion, the third end portion extends beyond the second end portion to form a third protruding portion, and a length L4 of the third protruding portion satisfies: 5mm≤L4≤10mm.

[0012] In some embodiments, a second diaphragm is disposed on a side of the second current collector away from the first diaphragm, the second diaphragm has a fourth end portion, the fourth end portion exceeds the second end portion to form a fourth protruding portion, and a length L5 of the fourth protruding portion satisfies: 5mm≤L5≤10mm;

[0013] Wherein, the third end portion and the fourth end portion are provided with an adhesive layer, and the adhesive layer bonds the third end portion and the fourth end portion together.

[0014] In some embodiments, a distance L6 by which the second end portion exceeds the first end portion satisfies: 1 mm ≤ L6 ≤ 30 mm.

[0015] In some embodiments, the first current collector is a positive electrode current collector, the second current collector is a negative electrode current collector, the first electrode tab is a positive electrode tab, the second electrode tab is a negative electrode tab, the first active material layer is a positive electrode active material layer, and the second active material layer is a negative electrode active material layer.

[0016] Correspondingly, the utility model also proposes a battery, comprising the battery cell described in any of the above embodiments.

[0017] Correspondingly, the utility model also provides an electronic device, comprising the battery described in any one of the above embodiments.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] In the technical solution of the utility model, in order to effectively utilize the internal space of the battery cell and improve the energy density of the battery cell, a first active material layer is coated on the first empty foil area of ​​the first end portion of the first current collector, and a second active material layer is coated on the second empty foil area of ​​the second end portion of the second current collector. The first active material layer and the second active material layer are arranged relative to each other, so that the first current collector and the second current collector can deintercalate and intercalate lithium ions between the empty foil areas of the end portions, thereby realizing the charging and discharging of the battery cell at the empty foil areas.

[0020] Furthermore, in view of the fact that in the traditional design of the battery cell, the first pole ear and the second pole ear (i.e., the positive pole ear and the negative pole ear) are designed to be relatively dispersed, which is not conducive to the concentrated coating of the active material layer in the empty foil area, in order to increase the concentrated coating area of ​​the active material layer in the empty foil area and further improve the charge and discharge performance between the active material layers, in the utility model, the first pole ear and the second pole ear are designed eccentrically, which can shorten the interval between the first pole ear and the second pole ear, so that the first pole ear and the second pole ear are relatively close. Exemplarily, for example, the first pole ear and the second pole ear can be both arranged on the side of the current collector away from the end head, so that the empty foil area of ​​the end head can be more concentrated together, that is, most of the empty foil area is arranged between the pole ear and the end head. Under the condition of meeting the design requirements of the battery cell, it is equivalent to effectively extending the length of the empty foil area, leaving more empty foil area at the end head for coating the active material layer, and utilizing the space inside the battery cell to a greater extent, which is conducive to coating a larger amount of the first active material layer in the first empty foil area and a larger amount of the second active material layer in the second empty foil area. The increase in the coating amount of the first active material layer and the second active material layer can be more conducive to improving the overall charge and discharge performance of the battery cell, thereby further improving the energy density of the battery cell.

[0021] The battery and electronic device using the above-mentioned battery cell have higher energy density, which is beneficial to improving the battery life of the battery and the electronic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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.

[0023] Figure 1 A schematic diagram of the overall structure of a battery cell provided in one embodiment of the utility model;

[0024] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0025] Figure 3 A schematic diagram of the relative position relationship between the first current collector, the second current collector, the first adhesive tape, the second adhesive tape, the first separator and the second separator in a battery cell provided by an embodiment of the utility model;

[0026] Figure 4 A schematic diagram of the overall structure of a battery cell provided in another embodiment of the utility model;

[0027] Figure 5 A schematic diagram of the overall structure of a battery cell provided in yet another embodiment of the utility model;

[0028] Figure 6 A schematic diagram of the overall structure of a battery cell provided in another embodiment of the utility model;

[0029] Figure 7 A schematic diagram of the relative position relationship between the first current collector, the second current collector, the first adhesive tape, the second adhesive tape, the first separator and the second separator in a battery cell provided in another embodiment of the utility model.

[0030] Description of Figure Numbers:

[0031] 100-first current collector;

[0032] 110 - first end portion; 120 - first electrode tab; 130 - first adhesive tape; 140 - first active material layer;

[0033] 200-second collector;

[0034] 210 - second end portion; 220 - second electrode tab; 230 - second adhesive tape; 240 - second active material layer;

[0035] 241 - first protruding portion; 242 - second protruding portion;

[0036] 300-first diaphragm;

[0037] 310 - third end portion; 320 - third protruding portion;

[0038] 400 - second diaphragm;

[0039] 410 - fourth end portion; 420 - fourth protruding portion;

[0040] 500-adhesive layer.

[0041] 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

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Lithium-ion battery is a secondary battery, which consists of an internal bare cell and a 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 materials to participate in charging and discharging. In the head area of ​​the positive and negative electrode sheets, a section of the current collector is reserved without coating the active material layer for welding the pole ears. As the market's requirements for the energy density of the battery cell become higher and higher, the longer section of the empty foil area reserved at the head of the current collector fails to effectively exert the charging and discharging performance, resulting in low space utilization inside the battery cell, thereby reducing the energy density of the battery cell.

[0046] In order to solve the technical problems of low space utilization inside the battery cell and low energy density of the battery cell caused by the empty foil area reserved at the head of the current collector, refer to Figures 1 to 3An embodiment of the utility model provides a battery cell, including a first current collector 100 and a second current collector 200, the first current collector 100 having a first end portion 110, a first empty foil area is arranged on a side of the first current collector 100 close to the first end portion 110, the first empty foil area is used to weld a first pole ear 120, a first adhesive tape 130 is arranged at the first pole ear 120, the polarity of the second current collector 200 is opposite to that of the first current collector 100, the second current collector 200 has a second end portion 210, the second end portion 210 exceeds the first end portion 110, a second empty foil area is arranged on a side of the second current collector 200 close to the second end portion 210, the second empty foil area is used to weld a second pole ear 220, and a second adhesive tape 230 is arranged at the second pole ear 220. The first pole tab 120 is disposed on the side of the first current collector 100 away from the first end portion 110, and the second pole tab 220 is disposed close to the first pole tab 120, so that the distance L1 between the first pole tab 120 and the second pole tab 220 satisfies: 6mm≤L1≤10mm (the distance L1 here may specifically be the distance between the center line of the first pole tab 120 and the center line of the second pole tab 220). For example, for example, the value of L1 may be 6mm, 7mm, 8mm, 9mm, 10mm, etc. A first active material layer 140 is disposed on the surface of the first current collector 100 between one end of the first adhesive tape 130 close to the first end portion 110 and the first end portion 110, and a second active material layer 240 is disposed on the surface of the second current collector 200 between one end of the second adhesive tape 230 close to the second end portion 210 and the second end portion 210, and the first active material layer 140 and the second active material layer 240 are disposed opposite to each other.

[0047] Specifically, due to the influence of the structure of the battery cell itself, it is necessary to install a pole ear on the current collector, and a section of empty foil area will be formed at the installation of the pole ear. Usually, active material is not coated on the empty foil area, so that the battery cell cannot be charged and discharged in the empty foil area, wasting this part of the space in the empty foil area. In order to effectively utilize the internal space of the battery cell and improve the energy density of the battery cell, in this embodiment, a first active material layer 140 is coated on the first empty foil area of ​​the first end head 110 of the first current collector 100, and a second active material layer 240 is coated on the second empty foil area of ​​the second end head 210 of the second current collector 200. The first active material layer 140 and the second active material layer 240 are arranged relative to each other, so that the first current collector 100 and the second current collector 200 can deintercalate and embed lithium ions between the empty foil areas of the end heads, thereby realizing the charging and discharging of the battery cell at the empty foil area.

[0048] Furthermore, in view of the fact that in the conventional design of the battery cell, the first pole ear 120 and the second pole ear 220 (i.e., the positive pole ear and the negative pole ear) are designed to be relatively dispersed, which is not conducive to the concentrated coating of the active material layer in the empty foil area, in order to increase the concentrated coating area of ​​the active material layer in the empty foil area and further improve the charge and discharge performance between the active material layers, in this embodiment, the first pole ear 120 and the second pole ear 220 are designed to be eccentric, which can shorten the interval between the first pole ear 120 and the second pole ear 220, so that the first pole ear 120 and the second pole ear 220 are relatively close. For example, , the first pole ear 120 and the second pole ear 220 can be both arranged on the side of the current collector away from the end head, so that the empty foil area of ​​the end head can be more concentrated together, that is, most of the empty foil area is arranged between the pole ear and the end head, which is equivalent to effectively extending the length of the empty foil area in accordance with the design requirements of the battery cell, leaving more empty foil area at the end head for coating the active material layer, and utilizing the space inside the battery cell to a greater extent, which is conducive to coating more first active material layer 140 on the first empty foil area and more second active material layer 240 on the second empty foil area. The increase in the coating amount of the first active material layer 140 and the second active material layer 240 can be more conducive to improving the overall charge and discharge performance of the battery cell, thereby increasing the energy density of the battery cell to a greater extent.

[0049] In other embodiments, reference Figure 6 to Figure 7 The first pole ear 120 and the second pole ear 220 are designed to be eccentric, and the interval between the first pole ear 120 and the second pole ear 220 can also be extended, so that the first pole ear 120 and the second pole ear 220 are relatively far away from each other. For example, the first pole ear 120 can be arranged on the side of the current collector away from the end head, and the second pole ear 220 can be arranged on the side of the current collector close to the end head, so that the distance between the first pole ear 120 and the second pole ear 220 is between 30 mm and 50 mm (including the end value). In this way, most of the empty foil area is arranged between the first pole ear 120 and the second pole ear 220, and the purpose of concentrating the empty foil area at the end head can be achieved. Under the condition of meeting the design requirements of the battery cell, it is equivalent to effectively extending the length of the empty foil area, leaving more empty foil area at the end head for coating the active material layer, making greater use of the space inside the battery cell, and thus improving the overall energy density of the battery cell to a greater extent.

[0050] It should be noted that the current collector needs to undergo a lamination process or a winding process to form a battery cell. Taking the wound battery cell as an example, the first end portion 110 and the second end portion 210 in this embodiment refer to the starting ends of the winding of the battery cell.

[0051] In some embodiments, reference Figure 4Between one end of the first adhesive tape 130 close to the first end head 110 and the first end head 110, first active material layers 140 coated relatively are provided on both side surfaces of the first current collector 100, and relative to the first active material layer 140, a second active material layer 240 is provided on the surface of the second current collector 200.

[0052] Specifically, in order to further improve the energy density of the battery cell and make full use of the empty foil area at the end of the current collector, in this embodiment, a layer of active material is coated on the surface of each side of the empty foil area of ​​the current collector, so that both sides of the empty foil area can participate in the charging and discharging of the battery cell. Exemplarily, for example, in addition to coating a layer of the first active material layer 140 between one end of the first adhesive tape 130 close to the first end portion 110 and the first end portion 110, and on one side of the first empty foil area, correspondingly, coating a layer of the second active material layer 240 between one end of the second adhesive tape 230 close to the second end portion 210 and the second end portion 210, and on one side of the second empty foil area, a layer of the first active material layer 140 may also be coated between one end of the first adhesive tape 130 close to the first end portion 110 and the first end portion 110, on the other side opposite to the first empty foil area, and correspondingly, a layer of the second active material layer 240 is also coated at a position on the surface of the second current collector 200 corresponding to the first active material layer 140 (for example, at a position after the second current collector 200 is wound), so that the first active material layer 140 and the second active material layer 240 can participate in normal charging and discharging.

[0053] By coating the first active material layer 140 on both sides of the first empty foil area, and correspondingly coating two layers of the second active material layer 240 on the second current collector 200 relative to the position of the first active material layer 140, the utilization rate of the internal space of the battery cell can be further improved, and the energy density of the battery cell can be further improved, so that both sides of the empty foil area of ​​the current collector can be charged and discharged.

[0054] In some embodiments, reference 1 to Figure 7 Both ends of the second active material layer 240 extend beyond both ends of the first active material layer 140 , so that one end of the second active material layer 240 forms a first extending portion 241 , and the other end of the second active material layer 240 forms a second extending portion 242 .

[0055] Specifically, in order to ensure the safety of the battery cell and prevent lithium deposition inside the battery cell, in this embodiment, the second active material layer 240 needs to completely cover the first active material layer 140. During the charging process of the battery cell, lithium ions will be deintercalated by the first active material layer 140, and after migration, the lithium ions will be embedded in the second active material layer 240. By designing the coating area of ​​the second active material layer 240 to be larger than the coating area of ​​the first active material layer 140, it can be ensured that the lithium ions deintercalated from each layer of the first active material layer 140 can be completely absorbed by the corresponding second active material layer 240, so that lithium deposition will not occur on the surface of the second current collector 200, and the precipitated lithium element will not form lithium dendrites to pierce the isolation membrane 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 are in direct contact, causing a short circuit in the battery cell.

[0056] In some embodiments, reference Figure 3 and Figure 7 , the length L2 of the first protruding portion 241 satisfies: L2 ≥ 2 mm, and the length L3 of the second protruding portion 242 satisfies: L3 ≥ 2 mm. Exemplarily, for example, the value of L2 can be 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, etc., and the value of L3 can be 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, etc.

[0057] Specifically, in order to ensure that the lithium ions extracted from the first active material layer 140 can be completely absorbed by the second active material layer 240 and prevent the occurrence of lithium precipitation on the surface of the second current collector 200, in this embodiment, the length of the two ends of the second active material layer 240 beyond the two ends of the first active material layer 140 is specifically limited within a certain range, that is, the two ends of the second active material layer 240 need to have a margin of at least 2 mm compared to the two ends of the first active material layer 140. Over-designing the second active material layer 240 can improve the lithium embedding capacity of the second active material layer 240, prevent the second active material layer 240 from reaching saturation in advance, and ensure that the lithium ions extracted from the first active material layer 140 can be completely embedded in the second active material layer 240.

[0058] It should be noted that the length of the first protruding portion 241 and the length of the second protruding portion 242 should not be designed to be too long. If the length of the protruding portion is too long, since the first active material layer 140 cannot deintercalate more lithium ions, it will lead to waste of materials of the second active material layer 240. For example, for example, the maximum value of the length of the first protruding portion 241 and the length of the second protruding portion 242 can be designed to be 5mm, that is, the length L2 of the first protruding portion 241 satisfies: 2mm≤L2≤5mm, and the length L3 of the second protruding portion 242 satisfies: 2mm≤L3≤5mm. The length of the first protruding portion 241 and the length of the second protruding portion 242 should not be designed to be too short. If the length of the protruding portion is too short, it cannot be effectively guaranteed that the second active material layer 240 will absorb all the lithium ions deintercalated by the first active material layer 140, and the safety of the battery cell cannot be guaranteed.

[0059] Furthermore, considering that a larger amount of active material layer is coated, it is more beneficial to improve the overall energy density of the battery cell. In the present embodiment, the second active material layer 240 can extend onto the second adhesive tape 230. In this way, the coating lengths of the first active material layer 140 and the second active material layer 240 can be increased, thereby more effectively improving the space utilization of the empty foil area and enhancing the overall energy density of the battery cell.

[0060] In some embodiments, the gram capacity of the second active material layer 240 can be higher than the gram capacity of the first active material layer 140. According to the formula "design capacity of the battery cell = coating surface density * active material ratio * active material gram capacity * pole piece coating area", when other parameters are constant, the design capacity of the battery cell can be increased by increasing the active material gram capacity. Therefore, when the coating length of the second active material layer 240 is constant, by increasing the gram capacity of the second active material layer 240, on the one hand, the over-design of the capacity of the second current collector 200 can be achieved, so that the capacity of the second current collector 200 to accommodate lithium ions is higher than the capacity of the first current collector 100 to accommodate lithium ions, so as to ensure that the lithium ions extracted from the first current collector 100 can be absorbed by the second current collector 200, without causing the lithium ions to be free on the surface of the second current collector 200, and avoiding the free lithium ions to precipitate lithium monomers on the surface of the second current collector 200 after obtaining electrons, thereby affecting the safety performance of the battery cell. On the other hand, while ensuring that the second current collector 200 has the same ability to accommodate lithium ions, increasing the gram capacity of the second active material layer 240 can also reduce the coating length of the second active material layer 240, reduce the material consumption of the second active material layer 240, and reduce the coating space of the second active material layer 240.

[0061] In some embodiments, for example, the first active material layer 140 may be a lithium cobalt oxide structure, a lithium iron phosphate structure, or a lithium iron manganese phosphate structure, and the second active material layer 240 may be a silicon-carbon composite structure or a high-gram capacity graphite structure.

[0062] In some embodiments, reference Figures 1 to 7 A first diaphragm 300 is disposed between the first current collector 100 and the second current collector 200. The first diaphragm 300 has a third end portion 310. The third end portion 310 exceeds the second end portion 210 to form a third protruding portion 320. The length L4 of the third protruding portion 320 satisfies: 5mm≤L4≤10mm. For example, the value of L4 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

[0063] Specifically, in order to prevent the first current collector 100 and the second current collector 200 in the battery cell from directly contacting each other and causing a short circuit in the battery cell, a layer of isolation film is usually provided between the first current collector 100 and the second current collector 200. The isolation film can only allow lithium ions to pass through, thereby separating the first current collector 100 and the second current collector 200. However, since the battery cell is affected by heating, charging and discharging and other factors during use, the head of the isolation film will shrink. In order to prevent the second current collector 200 from being exposed due to the shrinkage of the isolation film (since the end of the second current collector 200 exceeds the end of the first current collector 100, the shrinkage of the isolation film will cause the second current collector 200 to be exposed), and after the exposure, the isolation film will be in contact with the first current collector 10 0 contact and short circuit occurs, in the present embodiment, the end portion of the first diaphragm 300 arranged between the first current collector 100 and the second current collector 200 is extended out of the end portion of the second current collector 200 by 5mm-10mm (including the end value), so that even when the battery cell is affected by factors such as heating, charging and discharging, resulting in the third end portion 310 of the first diaphragm 300 shrinking, since the first diaphragm 300 has a third protruding portion 320 extending out of the second current collector 200, the first diaphragm 300 has room for shrinking. Even if the first diaphragm 300 shrinks, it can still cover the second current collector 200, thereby preventing the second current collector 200 from being exposed and contacting the first current collector 100, thereby causing the risk of short circuit in the battery cell.

[0064] In addition, since the third protruding portion 320 is a straight section, that is, the first end portion 110 of the first current collector 100, the second end portion 210 of the second current collector 200 and the third end portion 310 of the first diaphragm 300 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.

[0065] In some embodiments, reference Figures 1 to 7 The second current collector 200 is provided with a second diaphragm 400 on one side away from the first diaphragm 300. The second diaphragm 400 has a fourth end portion 410. The fourth end portion 410 exceeds the second end portion 210 to form a fourth protruding portion 420. The length L5 of the fourth protruding portion 420 satisfies: 5mm≤L5≤10mm. For example, the value of L5 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. The third end portion 310 and the fourth end portion 410 are provided with an adhesive layer 500, and the adhesive layer 500 bonds the third end portion 310 and the fourth end portion 410 together.

[0066] Specifically, in a wound battery cell, in order to prevent the second current collector 200 from directly contacting itself during the winding process and causing a short circuit within the battery cell, in the present embodiment, a second diaphragm 400 is provided on the side of the second current collector 200 facing away from the first diaphragm 300. During the winding process of the battery cell, the second diaphragm 400 is wound together with the second current collector 200, thereby isolating different positions of the second current collector 200 after winding, and preventing the second current collector 200 from directly contacting itself.

[0067] Further, referring to the above embodiment, based on the same reasons as the above embodiment, that is, in order to prevent the second diaphragm 400 from shrinking and causing the second current collector 200 to leak after the battery cell is affected by factors such as heating, charging and discharging, and to avoid the second current collector 200 after leakage directly contacting itself and causing a short circuit in the battery cell, in this embodiment, the fourth end head 410 of the second diaphragm 400 is extended out of the second end head 210 of the second current collector 200. In this way, even if the battery cell is affected by factors such as heating, charging and discharging, causing the fourth end head 410 of the second diaphragm 400 to shrink, since the second diaphragm 400 has a fourth protruding portion 420 extending out of the second current collector 200, the second diaphragm 400 has room for shrinkage. Even if the second diaphragm 400 shrinks, it can still cover the second current collector 200, thereby preventing the second current collector 200 from directly contacting different positions of itself after leakage, thereby causing the risk of a short circuit in the battery cell.

[0068] Furthermore, in order to effectively fix the third end head 310 of the first diaphragm 300 and the fourth end head 410 of the second diaphragm 400 at the starting end of the winding of the battery cell and eliminate the risk of short circuit in the battery cell caused by the shrinkage of the diaphragm, in the present embodiment, the third end head 310 and the fourth end head 410 are bonded together by the adhesive layer 500, so that the third end head 310 and the fourth end head 410 can be stably positioned at the starting end of the winding of the battery cell. In this way, even under the influence of factors such as heating, charging and discharging of the battery cell, the third end head 310 and the fourth end head 410 will not shrink, that is, the first diaphragm 300 and the second diaphragm 400 can always cover the second current collector 200, and the second current collector 200 will not be exposed, and the second current collector 200 will not be in direct contact with the first current collector 100, or the second current collector 200 will not be in direct contact with different positions of itself, thereby effectively ensuring the safety performance of the battery cell during use.

[0069] In some embodiments, reference Figure 3 and Figure 7 , the distance L6 of the second end portion 210 beyond the first end portion 110 satisfies: 1mm≤L6≤30mm. Exemplarily, for example, the value of L6 can be 1mm, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, etc.

[0070] Specifically, referring to the above embodiment, since the end portions of the first diaphragm 300 and the second diaphragm 400 are fixed to the starting end of the winding of the battery cell by the adhesive layer 500, the first diaphragm 300 and the second diaphragm 400 will not shrink due to the heating, charging and discharging of the battery cell, and thus will not cause the first current collector 100 and the second current collector 200 to be in direct contact, thereby shortening the distance between the end portions of the first current collector 100 and the second current collector 200, so that the first empty foil area and the second empty foil area can be coated with a larger amount of active material layer, thereby giving full play to the charging and discharging performance of the active material layer and improving the overall energy density of the battery cell.

[0071] In some embodiments, the first current collector 100 is a positive electrode current collector, the second current collector 200 is a negative electrode current collector, the first pole ear 120 is a positive pole ear, the second pole ear 220 is a negative pole ear, the first active material layer 140 is a positive electrode active material layer, and the second active material layer 240 is a negative electrode active material layer. The above design meets the requirement of "anode wrapped cathode" in the battery cell design, that is, the negative electrode current collector needs to wrap the positive electrode current collector, which can effectively prevent short circuits in the battery cell and ensure the safety of the battery cell.

[0072] Correspondingly, another embodiment of the present invention further provides a battery, which includes the battery cell in any of the above embodiments.

[0073] Specifically, in this embodiment, the battery can be a lithium-ion battery or the like. The battery using the above battery cell has a higher energy density, which is beneficial to improving the battery's endurance. Thanks to the improvement of the above battery cell, the battery of this embodiment has the same technical effect as the above battery cell, which will not be described in detail here.

[0074] Correspondingly, another embodiment of the present invention further provides an electronic device, which includes the battery in any of the above embodiments.

[0075] Specifically, in this embodiment, the electronic device may be a mobile phone, a laptop computer, a photographic device, a new energy vehicle, etc. The electronic device using the above battery has a higher energy density, which is conducive to improving the endurance of the electronic device.

[0076] It should be noted that other contents of the battery cell, battery and electronic device disclosed in the present utility model can be found in the prior art and will not be described in detail here.

[0077] 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: A first current collector, wherein the first current collector has a first end portion, a first empty foil area is disposed on a side of the first current collector close to the first end portion, the first empty foil area is used for welding a first electrode tab, and a first adhesive tape is disposed at the first electrode tab; A second current collector, wherein the polarity of the second current collector is opposite to that of the first current collector, the second current collector has a second end portion, the second end portion exceeds the first end portion, a second empty foil area is provided on a side of the second current collector close to the second end portion, the second empty foil area is used for welding a second electrode tab, and a second adhesive tape is provided at the second electrode tab; The first electrode tab is disposed on a side of the first current collector away from the first end portion, and the second electrode tab is disposed close to the first electrode tab, so that a distance L1 between the first electrode tab and the second electrode tab satisfies: 6 mm ≤ L1 ≤ 10 mm; a first active material layer is disposed on the surface of the first current collector between an end of the first adhesive tape close to the first end portion and the first end portion; A second active material layer is disposed on the surface of the second current collector between one end of the second adhesive tape close to the second end portion and the second end portion, and the first active material layer and the second active material layer are disposed opposite to each other.

2. The battery cell according to claim 1, characterized in that: Between one end of the first adhesive tape close to the first end head and the first end head, the first active material layer coated oppositely is provided on both side surfaces of the first current collector; relative to the first active material layer, the second active material layer is provided on the surface of the second current collector.

3. The battery cell according to claim 2, characterized in that: Both ends of the second active material layer extend beyond both ends of the first active material layer, so that one end of the second active material layer forms a first extending portion, and the other end of the second active material layer forms a second extending portion.

4. The battery cell according to claim 3, characterized in that: The length L2 of the first protruding portion satisfies: L2≥2 mm, and the length L3 of the second protruding portion satisfies: L3≥2 mm.

5. The battery cell according to claim 1, characterized in that: A first diaphragm is disposed between the first current collector and the second current collector. The first diaphragm has a third end portion. The third end portion exceeds the second end portion to form a third protruding portion. The length L4 of the third protruding portion satisfies: 5mm≤L4≤10mm.

6. The battery cell according to claim 5, characterized in that: A second diaphragm is disposed on a side of the second current collector away from the first diaphragm, the second diaphragm has a fourth end portion, the fourth end portion exceeds the second end portion to form a fourth protruding portion, and a length L5 of the fourth protruding portion satisfies: 5mm≤L5≤10mm; Wherein, the third end portion and the fourth end portion are provided with an adhesive layer, and the adhesive layer bonds the third end portion and the fourth end portion together.

7. The battery cell according to any one of claims 1 to 6, characterized in that: A distance L6 by which the second end portion exceeds the first end portion satisfies: 1 mm ≤ L6 ≤ 30 mm.

8. The battery cell according to any one of claims 1 to 6, characterized in that: The first current collector is a positive electrode current collector, the second current collector is a negative electrode current collector, the first electrode tab is a positive electrode tab, the second electrode tab is a negative electrode tab, the first active material layer is a positive electrode active material layer, and the second active material layer is a negative electrode active material layer.

9. A battery, characterized in that A battery cell comprising the battery cell according to any one of claims 1 to 8.

10. An electronic device, characterized in that A battery comprising the battery of claim 9.

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