Battery cell and lithium ion battery

Abstract

The utility model discloses a battery cell and a lithium ion battery. The battery cell comprises a positive plate, a negative plate, a diaphragm, a positive lug and a negative lug, wherein the first welding part of the positive tab is welded on the positive plate, and the second welding part of the negative tab is welded on the negative plate; the first insulating layer at least covers the first welding part of the positive tab; the second insulating layer at least covers the second welding part of the negative tab; at least one of the first insulating layer and the second insulating layer is a ceramic coating. According to the utility model, the ceramic coating is adopted as the material of at least one of the first insulating layer and the second insulating layer, the first insulating layer is coated on the positive tab, and the second insulating layer is covered on the negative tab, so that thicker gummed paper is replaced, the space occupied by the gummed paper in the prior art is released, and the service life of the gummed paper is prolonged. And the lithium ion battery can have more space to improve the energy density.

Description

Technical Field

[0001] The utility model relates to the field of lithium-ion batteries, and particularly relates to a battery cell and a lithium-ion battery. Background Art

[0002] Lithium-ion batteries are favored due to their excellent electrochemical performance, environmental friendliness, fast charge and discharge capabilities, and strong endurance. Currently, they have been widely used in various electronic product fields, and thus users have higher requirements for all aspects of lithium-ion batteries.

[0003] In the existing battery cells of lithium-ion batteries, multiple pieces of adhesive tape need to be pasted at the position of the tab welding to protect the welding area, and the presence of these adhesive tapes will increase the thickness of the battery cell, thereby reducing the volume energy density of the lithium-ion battery. Summary of the Utility Model

[0004] The main object of the utility model is to propose a battery cell, aiming to solve the problem that the adhesive tape at the tab of the existing battery cell increases the thickness of the battery cell.

[0005] To achieve the above object, the utility model proposes a battery cell, which includes:

[0006] A positive electrode sheet;

[0007] A negative electrode sheet;

[0008] A separator, which is disposed between the positive electrode sheet and the negative electrode sheet;

[0009] A positive tab, which has a first welding portion and a first extending portion, the first welding portion is welded to the positive electrode sheet, and the first extending portion extends from the first welding portion and protrudes outside the positive electrode sheet;

[0010] A negative tab, which has a second welding portion and a second extending portion, the second welding portion is welded to the negative electrode sheet, and the second extending portion extends from the second welding portion and protrudes outside the negative electrode sheet;

[0011] A first insulating layer, which at least covers the first welding portion;

[0012] A second insulating layer, which at least covers the second welding portion;

[0013] At least one of the first insulating layer and the second insulating layer is a ceramic coating.

[0014] In some embodiments, both the first insulating layer and the second insulating layer are ceramic coatings; and / or,

[0015] The thickness range of the ceramic coating is 5μm - 20μm.

[0016] In some embodiments, a first tab groove is provided on one side of the positive electrode sheet, and the first welding portion and the first insulating layer are both disposed in the first tab groove.

[0017] In some embodiments, a second tab groove is provided on one side of the negative electrode sheet, and the second welding portion and the second insulating layer are both disposed in the second tab groove.

[0018] In some embodiments, a third insulating layer is further included;

[0019] A first groove is provided on the surface of the negative electrode sheet facing the first welding portion, and the third insulating layer is disposed in the first groove;

[0020] The third insulating layer is a ceramic coating.

[0021] In some embodiments, a fourth insulating layer is further included;

[0022] A second groove is provided on the surface of the positive electrode sheet facing the second welding portion, and the fourth insulating layer is disposed in the second groove;

[0023] The fourth insulating layer is a ceramic coating.

[0024] In some embodiments, the battery cell further includes a fifth insulating layer;

[0025] A third groove corresponding to the first tab groove is provided on the surface of the positive electrode sheet facing away from the first tab groove, and the fifth insulating layer is disposed in the third groove;

[0026] The fifth insulating layer is a ceramic coating.

[0027] In some embodiments, the battery cell further includes a sixth insulating layer;

[0028] A fourth groove is provided on the surface of the negative electrode sheet facing the fifth insulating layer, and the sixth insulating layer is disposed in the fourth groove;

[0029] The sixth insulating layer is a ceramic coating.

[0030] In some embodiments, the battery cell further includes a seventh insulating layer;

[0031] A fifth groove corresponding to the second tab groove is provided on the surface of the negative electrode sheet facing away from the second tab groove, and the seventh insulating layer is disposed in the fifth groove;

[0032] The seventh insulating layer is a ceramic coating.

[0033] In some embodiments, the battery cell further includes an eighth insulating layer;

[0034] The surface of the positive electrode sheet facing the fourth insulating layer is provided with a sixth groove, and the eighth insulating layer is disposed in the sixth groove;

[0035] The eighth insulating layer is a ceramic coating.

[0036] In some embodiments, the positive electrode sheet includes a positive current collector and a first active material layer and a second active material layer respectively disposed on two opposite surfaces of the positive current collector. The first tab groove and the second groove are disposed in the first active material layer, and the third groove and the sixth groove are disposed in the second active material layer;

[0037] A negative electrode sheet, which includes a negative current collector and a third active material layer and a fourth active material layer respectively disposed on two opposite surfaces of the negative current collector. The second tab groove and the first groove are disposed in the third active material layer, and the fourth groove and the fifth groove are disposed in the fourth active material layer.

[0038] In some embodiments, the width of the first groove is greater than or equal to the width of the first tab groove, the width of the second groove is greater than or equal to the width of the second tab groove, the width of the fourth groove is greater than or equal to the width of the third groove, and the width of the sixth groove is greater than or equal to the width of the fifth groove.

[0039] The present utility model further provides a lithium-ion battery, which includes a housing and the battery cell described in the foregoing embodiments, and the battery cell is disposed in the housing.

[0040] The present utility model uses a ceramic coating as the material of at least one of the first insulating layer and the second insulating layer. By coating the first insulating layer on the positive tab and covering the second insulating layer on the negative tab, the thicker adhesive tape is replaced, and the space occupied by the adhesive tape in the prior art is released, so that there is more space in the lithium-ion battery to improve the energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic structural view of an embodiment of the battery cell of the present utility model;

[0042] Figure 2 is Figure 1 a cross-sectional view at the positive tab in

[0043] Figure 3 is Figure 1 a cross-sectional view at the negative tab in

[0044] Figure 4 is a cross-sectional view of another embodiment of the battery cell of the present utility model;

[0045] Figure 5 is Figure 4Top view of the positive electrode sheet;

[0046] Figure 6 is Figure 4 Bottom view of the positive electrode sheet;

[0047] Figure 7 is Figure 4 Bottom view of the positive electrode sheet;

[0048] Figure 8 is Figure 4 Top view of the positive electrode sheet.

[0049] Reference numerals:

[0050] 100, positive electrode sheet; 110, positive electrode tab; 111, first welding part; 112, first extension part; 120, first insulating layer; 130, first tab groove; 140, second groove; 141, fourth insulating layer; 150, third groove; 151, fifth insulating layer; 160, sixth groove; 161, eighth insulating layer; 170, first active material layer; 180, second active material layer; 190, positive current collector; 200, negative electrode sheet; 210, negative electrode tab; 211, second welding part; 212, second extension part; 220, second insulating layer; 230, second tab groove; 240, first groove; 241, third insulating layer; 250, fourth groove; 251, sixth insulating layer; 260, fifth groove; 261, seventh insulating layer; 270, third active material layer; 280, fourth active material layer; 290, negative current collector; 300, separator. Detailed implementation manners

[0051] Next, the solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0052] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a certain specific posture (as shown in the accompanying drawings). If this specific posture changes, then the directional indications will also change accordingly.

[0053] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0054] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0055] The present utility model provides a battery cell. Referring to Figures 1-8 , the battery cell includes:

[0056] a positive electrode plate 100;

[0057] a negative electrode plate 200;

[0058] a separator 300, the separator 300 is disposed between the positive electrode plate 100 and the negative electrode plate 200;

[0059] a positive electrode tab 110, the positive electrode tab 110 has a first welding portion 111 and a first extension portion 112, the first welding portion 111 is welded to the positive electrode plate 100, and the first extension portion 112 extends from the first welding portion 111 and protrudes outside the positive electrode plate 100;

[0060] a negative electrode tab 210, the negative electrode tab 210 has a second welding portion 211 and a second extension portion 212, the second welding portion 211 is welded to the negative electrode plate 200, and the second extension portion 212 extends from the second welding portion 211 and protrudes outside the negative electrode plate 200;

[0061] a first insulating layer 120, the first insulating layer 120 at least covers the first welding portion 111;

[0062] a second insulating layer 220, the second insulating layer 220 at least covers the second welding portion 211;

[0063] At least one of the first insulating layer 120 and the second insulating layer 220 is a ceramic coating.

[0064] The battery cell can be a stacked type or a wound type. However, regardless of the type of battery cell, a separator 300 is provided between adjacent positive electrode sheets 100 and negative electrode sheets 200 to separate the two and prevent internal short circuit. It can be understood that the vertical positions of the positive electrode sheet 100 and the negative electrode sheet 200 are not fixed. The positive electrode sheet 100 can be on top or the negative electrode sheet 200 can be on top, and the positive electrode sheet 100 and the negative electrode sheet 200 do not need to be completely aligned. That is, the size of the overlapping part between the positive electrode sheet 100 and the negative electrode sheet 200 can be selected as needed.

[0065] Both the positive electrode sheet 100 and the negative electrode sheet 200 include a current collector and an active material. The active material can be provided on only one surface of the current collector or on both surfaces of the current collector at the same time. This embodiment does not limit this. The positive electrode tab 110 and the negative electrode tab 210 are usually provided on the current collector, and the connection methods include ultrasonic welding, laser welding, resistance welding, bonding, etc. It can be understood that the positive electrode tab 110 and the negative electrode tab 210 can also be provided above the current collector covered with the active material. In this case, only a groove needs to be opened in the active material to expose the current collector.

[0066] Different from using adhesive tape to paste, the first insulating layer 120 and the second insulating layer 220 can be coated on the positive electrode tab 110 and the negative electrode tab 210 by spraying, making the connection between the first insulating layer 120 and the second insulating layer 220 and the positive electrode tab 110 and the negative electrode tab 210 closer, minimizing the gaps at the joints, thereby reducing the volume of the prepared lithium-ion battery and increasing the volume energy density. Among them, since ceramic materials have a high melting point, excellent thermal stability and corrosion resistance, and can maintain their insulating properties in a high-temperature environment, at least one of the first insulating layer 120 and the second insulating layer 220 is a ceramic coating to improve its insulating and protective effects. And wrinkles and bubbles are easily generated during the pasting process of the adhesive tape, resulting in poor appearance. After the electrolyte is injected into the battery cell, the viscosity effect of the adhesive tape becomes worse after being soaked in the electrolyte, affecting the protection effect. Using a ceramic coating to replace the adhesive tape has a better protection effect on the positive electrode tab 110 and the negative electrode tab 210 and a longer service life.

[0067] The present utility model uses a ceramic coating as the material of at least one of the first insulating layer 120 and the second insulating layer 220. By coating the first insulating layer 120 on the positive electrode tab 110 and covering the second insulating layer 220 on the negative electrode tab 210, the thicker adhesive tape is replaced, releasing the space occupied by the adhesive tape in the prior art, so that there is more space in the lithium-ion battery to increase the energy density.

[0068] In some embodiments, both the first insulating layer 120 and the second insulating layer 220 are ceramic coatings; and / or,

[0069] The thickness range of the ceramic coating is 5μm to 20μm.

[0070] If the thickness of the ceramic coating is less than 5μm, it is too thin and the structural strength is low. It is very likely that under external force factors, such as dropping, being squeezed, etc., or the burrs on the tab damage the ceramic coating, resulting in internal thermal runaway; if the thickness of the ceramic coating is greater than 20μm, it is too thick and cannot achieve a good effect of releasing the space occupied by the adhesive tape. Therefore, controlling the thickness of the ceramic coating between 5μm and 20μm can ensure its good insulation and protection effects while improving the volumetric energy density of the lithium-ion battery.

[0071] As Figures 5-8 shown, in some embodiments, a first tab groove 130 is provided on one side of the positive electrode sheet 100, and the first welding portion 111 and the first insulating layer 120 are both provided in the first tab groove 130.

[0072] By providing the first tab groove 130 on the positive electrode sheet 100, the first welding portion 111 and the first insulating layer 120 of the positive tab 110 can be accommodated in the first tab groove 130, that is, the positive tab 110 and the first insulating layer 120 do not protrude from the positive electrode sheet 100 in the thickness direction. When the positive electrode sheet 100 is stacked on the negative electrode sheet 200 or wound together with the negative electrode sheet 200 to form a core, the connection between the positive electrode sheet 100 and the negative electrode sheet 200 is closer, without generating extra gaps, further improving the volumetric energy density of the prepared lithium-ion battery.

[0073] Among them, the current collector can be recessed from the surface inward to form the first tab groove 130 in the empty foil area of the positive electrode sheet 100, that is, the area not covered with the active material; the first tab groove 130 can also be provided in the area covered with the active material. At this time, the active material serves as the side wall of the first tab groove 130, and the current collector serves as the bottom wall of the first tab groove 130.

[0074] As Figures 2-4 shown, in some embodiments, a second tab groove 230 is provided on one side of the negative electrode sheet 200, and the second welding portion 211 and the second insulating layer 220 are both provided in the second tab groove 230.

[0075] The setting of the second tab groove 230 is similar to that of the first tab groove 130 and will not be elaborated here. It can be understood that the first tab groove 130 and the second tab groove 230 can be provided simultaneously in the same battery cell, or only one of them can be provided; when both are provided, it has a better effect on improving the volumetric energy density of the lithium-ion battery.

[0076] As Figures 2-4 shown, in some embodiments, a third insulating layer 241 is further included;

[0077] The surface of the negative electrode sheet 200 facing the first welding portion 111 is provided with a first groove 240, and a third insulating layer 241 is disposed in the first groove 240;

[0078] The third insulating layer 241 is a ceramic coating.

[0079] By means of the first groove 240 provided corresponding to the first pole ear groove 130, the distance between the positive pole ear 110 and the negative electrode sheet 200 is extended, preventing the positive pole ear 110 from contacting the negative electrode sheet 200 in case of accidents such as collision or extrusion, which may cause internal short circuit. At the same time, the third insulating layer 241 is disposed in the first groove 240 to further improve the isolation effect between the positive pole ear 110 and the negative pole ear 210, so as to better protect the positive pole ear 110.

[0080] As Figures 2-4 shown, in some embodiments, a fourth insulating layer 141 is further included;

[0081] The surface of the positive electrode sheet 100 facing the second welding portion 211 is provided with a second groove 140, and the fourth insulating layer 141 is disposed in the second groove 140;

[0082] The fourth insulating layer 141 is a ceramic coating.

[0083] The settings of the fourth insulating layer 141 and the second groove 140 are similar to those of the third insulating layer 241 and the first groove 240, and will not be elaborated here.

[0084] As Figures 2-4 shown, in some embodiments, the battery cell further includes a fifth insulating layer 151;

[0085] The surface of the positive electrode sheet 100 facing away from the first pole ear groove 130 is provided with a third groove 150 corresponding to the first pole ear groove 130, and the fifth insulating layer 151 is disposed in the third groove 150;

[0086] The fifth insulating layer 151 is a ceramic coating.

[0087] When the positive pole ear 110 is welded to the positive electrode sheet 100 by means such as ultrasonic welding, the back surface of the positive pole ear 110 may be damaged due to welding, and problems such as piercing the separator 300 may easily occur here, resulting in direct contact between the positive pole ear 110 and the negative electrode sheet 200, causing internal short circuit. Therefore, by providing the third groove 150 and the fifth insulating layer 151, the negative electrode sheet 200 on the back side of the positive pole ear 110 is protected by the fifth insulating layer 151, improving the puncture performance of the lithium-ion battery and enhancing the safety performance of the battery cell; while the third groove 150 can accommodate the fifth insulating layer 151, preventing it from occupying extra space and causing a reduction in the volume energy density of the lithium-ion battery.

[0088] As Figures 2-4 shown, in some embodiments, the battery cell further includes a sixth insulating layer 251;

[0089] On the surface of the negative electrode sheet 200 facing the fifth insulating layer 151, a fourth groove 250 is provided, and a sixth insulating layer 251 is disposed in the fourth groove 250;

[0090] The sixth insulating layer 251 is a ceramic coating.

[0091] Through the combination of the sixth insulating layer 251 in the fourth groove 250 and the fifth insulating layer 151 in the third groove 150, the effect of preventing the possible internal short circuit phenomenon at the back of the positive electrode tab 110 in this embodiment is improved, and the safety hazard is reduced.

[0092] As Figures 2-4 shown, in some embodiments, the battery cell further includes a seventh insulating layer 261;

[0093] On the surface of the negative electrode sheet 200 facing away from the second electrode tab groove 230, a fifth groove 260 is provided corresponding to the second electrode tab groove 230, and a seventh insulating layer 261 is disposed in the fifth groove 260;

[0094] The seventh insulating layer 261 is a ceramic coating.

[0095] The setting manner of the seventh insulating layer 261 and the fifth groove 260 is similar to that of the fifth insulating layer 151 and the third groove 150, and will not be described herein again.

[0096] As Figures 2-4 shown, in some embodiments, the battery cell further includes an eighth insulating layer 161;

[0097] On the surface of the positive electrode sheet 100 facing the fourth insulating layer 141, a sixth groove 160 is provided, and an eighth insulating layer 161 is disposed in the sixth groove 160;

[0098] The eighth insulating layer 161 is a ceramic coating.

[0099] The setting manner of the eighth insulating layer 161 and the sixth groove 160 is similar to that of the sixth insulating layer 251 and the fourth groove 250, and will not be described herein again.

[0100] As Figure 4 shown, in some embodiments, the positive electrode sheet 100 includes a positive current collector 190 and a first active material layer 170 and a second active material layer 180 respectively disposed on two opposite surfaces of the positive current collector 190. The first electrode tab groove 130 and the second groove 140 are provided in the first active material layer 170, and the third groove 150 and the sixth groove 160 are provided in the second active material layer 180;

[0101] The negative electrode sheet 200 includes a negative current collector 290, and a third active material layer 270 and a fourth active material layer 280 disposed on two opposite surfaces of the negative current collector 290 respectively. A second tab groove 230 and a first groove 240 are provided in the third active material layer 270, and a fourth groove 250 and a fifth groove 260 are provided in the fourth active material layer 280.

[0102] At this time, the battery cell in this embodiment is a wound type, and various tab grooves and grooves in the foregoing embodiments are all provided in the active material layer. However, due to the risk of short circuit between the positive tab 110 and the third active material layer 270 and the fourth active material layer 280 on the negative electrode sheet 200, a first groove 240 is opened on the negative electrode sheet 200 to face the first tab groove 130, so as to increase the distance between the positive tab 110 and the third active material layer 270. At the same time, a fourth groove 250 is opened on the other side of the negative electrode sheet 200 to increase the distance between the third groove 150 on the back of the positive tab 110 and the fourth active material layer 280, further reducing the probability of internal short circuit. Similar settings are also made for the negative tab 210 and the first active material layer 170 and the second active material layer 180 on the positive electrode sheet 100, which will not be elaborated here.

[0103] In some embodiments, the width of the first groove 240 is greater than or equal to the width of the first tab groove 130, the width of the second groove 140 is greater than or equal to the width of the second tab groove 230, the width of the fourth groove 250 is greater than or equal to the width of the third groove 150, and the width of the sixth groove 160 is greater than or equal to the width of the fifth groove 260.

[0104] Taking the first groove 240 and the first tab groove 130 as an example, the first groove 240 is provided corresponding to the first tab groove 130, so that the width of the first groove 240 is greater than or equal to the width of the first tab groove 130, that is, it is ensured that the first groove 240 fully covers the range of the first tab groove 130, avoiding the situation where the positive tab 110 directly contacts the side wall of the first groove 240, and improving the safety performance of the battery cell. The structures of the others are similar, which will not be elaborated here.

[0105] The lithium-ion battery further proposed by the present utility model includes a housing and a battery cell. The specific structure of the battery cell refers to the foregoing embodiments. Since this lithium-ion battery adopts all the technical solutions of the above-mentioned all embodiments, it at least has all the technical effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated one by one here. Among them, the battery cell is disposed in the housing. It can be understood that the housing can be structures such as an aluminum-plastic film or a steel shell, and this embodiment does not limit this.

[0106] The above are only some or preferred embodiments of the present utility model. Neither the text nor the drawings can limit the scope of protection of the present utility model. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model under the concept of an integral whole of the present utility model, or any direct / indirect application in other related technical fields, is included in the scope of protection of the present utility model.

Claims

1. A battery cell, characterized in that: The battery cell includes: Positive electrode; Negative electrode; A diaphragm, the diaphragm is disposed between the positive electrode sheet and the negative electrode sheet; A positive electrode ear, the positive electrode ear having a first welding portion and a first extension portion, the first welding portion is welded to the positive electrode sheet, and the first extension portion extends from the first welding portion and protrudes outside the positive electrode sheet; A negative electrode ear, the negative electrode ear having a second welding portion and a second extension portion, the second welding portion is welded to the negative electrode sheet, and the second extension portion extends from the second welding portion and protrudes outside the negative electrode sheet; a first insulating layer, wherein the first insulating layer at least covers the first welding portion; a second insulating layer, wherein the second insulating layer at least covers the second welding portion; At least one of the first insulating layer and the second insulating layer is a ceramic coating.

2. The battery cell according to claim 1, characterized in that: The first insulating layer and the second insulating layer are both ceramic coatings; and / or, The thickness of the ceramic coating ranges from 5 μm to 20 μm.

3. The battery cell according to claim 1 or 2, characterized in that: A first electrode tab groove is provided on one side of the positive electrode sheet, and the first welding portion and the first insulating layer are both provided in the first electrode tab groove.

4. The battery cell according to claim 3, characterized in that: A second pole tab groove is provided on one side of the negative electrode sheet, and the second welding portion and the second insulating layer are both provided in the second pole tab groove.

5. The battery cell according to claim 4, characterized in that: The battery core also includes a third insulating layer; A first groove is provided on the surface of the negative electrode sheet facing the first welding portion, and the third insulating layer is provided in the first groove; The third insulating layer is a ceramic coating.

6. The battery cell according to claim 5, characterized in that: The battery core further includes a fourth insulating layer; A second groove is provided on the surface of the positive electrode sheet facing the second welding portion, and the fourth insulating layer is provided in the second groove; The fourth insulating layer is a ceramic coating.

7. The battery cell according to claim 6, characterized in that: The battery core also includes a fifth insulating layer; A third groove is provided on the surface of the positive electrode sheet facing away from the first electrode tab groove and corresponding to the first electrode tab groove, and the fifth insulating layer is provided in the third groove; The fifth insulating layer is a ceramic coating.

8. The battery cell according to claim 7, characterized in that: The battery core further includes a sixth insulating layer; A fourth groove is provided on the surface of the negative electrode sheet facing the fifth insulating layer, and the sixth insulating layer is provided in the fourth groove; The sixth insulating layer is a ceramic coating.

9. The battery cell according to claim 8, characterized in that: The battery core also includes a seventh insulating layer; A fifth groove is provided on the surface of the negative electrode sheet facing away from the second electrode tab groove and corresponding to the second electrode tab groove, and the seventh insulating layer is provided in the fifth groove; The seventh insulating layer is a ceramic coating.

10. The battery cell according to claim 9, characterized in that: The battery core also includes an eighth insulating layer; A sixth groove is provided on the surface of the positive electrode sheet facing the fourth insulating layer, and the eighth insulating layer is provided in the sixth groove; The eighth insulating layer is a ceramic coating.

11. The battery cell according to claim 10, characterized in that: The positive electrode sheet comprises a positive electrode current collector and a first active material layer and a second active material layer respectively arranged on two opposite surfaces of the positive electrode current collector, the first electrode tab groove and the second groove are arranged in the first active material layer, and the third groove and the sixth groove are arranged in the second active material layer; The negative electrode sheet includes a negative electrode current collector and a third active material layer and a fourth active material layer respectively arranged on two opposite surfaces of the negative electrode current collector, the second electrode tab groove and the first groove are arranged in the third active material layer, and the fourth groove and the fifth groove are arranged in the fourth active material layer.

12. The battery cell according to claim 10, characterized in that: The width of the first groove is greater than or equal to the width of the first pole lug groove, the width of the second groove is greater than or equal to the width of the second pole lug groove, the width of the fourth groove is greater than or equal to the width of the third groove, and the width of the sixth groove is greater than or equal to the width of the fifth groove.

13. A lithium ion battery, characterized in that: The invention comprises a housing and the battery core according to any one of claims 1 to 12, wherein the battery core is arranged in the housing.

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