Secondary battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a secondary battery which comprises a shell, the cover plate assembly is connected with the shell, and the cover plate assembly is provided with a pole column; the electrode assembly comprises a plurality of layers of electrode plates and a plurality of layers of tabs led out from at least first edges of the plurality of layers of electrode plates, and the plurality of layers of tabs are attached to each other to form a tab stack; the tab stacking body is provided with a bending part, the first side of the tab stacking body is provided with a first insulating layer and a second insulating layer, the first insulating layer and the second insulating layer are arranged at an interval along the surface of the tab stacking body, and the first insulating layer and the second insulating layer are respectively arranged by avoiding the bending part. According to the utility model, the insulation layer can be effectively prevented from being separated due to inconsistent elastic modulus and yield strength in the bending process, and the safety risk caused by the fact that the insulation layer is adhered with foreign matters such as metal particles or dust is avoided.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the battery technical field, concretely relates to a secondary battery. BACKGROUND

[0002] The tab and the pole are generally connected by welding, in order to avoid the slag in the welding process to cause pollution to the surrounding area, generally will be pasted in the non-welding area of tab one layer of insulating layer. In addition, after the tab and the pole are welded, in order to prevent the welding area and the electrode sheet contact short circuit, still will be pasted one layer of insulating layer in the welding area. The prior art when pasting these insulating layers, in order to guarantee that the insulating layer will be fully covered tab, generally will make these insulating layers between the overlapping area, however when the electrode sheet is loaded into the shell, the welding area of tab and the root of tab generally will form the bending part, and the overlapping area of above-mentioned insulating layer will be just located on the bending part with great probability, because the elastic modulus, yield strength of insulating layer and tab are inconsistent in the bending process, therefore, the insulating layer and tab will exist certain separation, causes the insulating layer to come off, at this time, the back glue of insulating layer will be bonded metal particles, dust and other foreign matters, causes the security risk. SUMMARY

[0003] In view of the above-mentioned defects of prior art, the utility model aims at providing a secondary battery capable of preventing the tab insulating layer from coming off and improving the safety of battery.

[0004] To achieve the above object and other related objects, the utility model provides a secondary battery, which comprises:

[0005] A shell, at least one end of the shell is provided with an opening;

[0006] A cover plate assembly, the cover plate assembly is connected with the shell and closes the opening, and the cover plate assembly is provided with a pole;

[0007] An electrode assembly, comprising a plurality of electrode sheets and a plurality of tabs led out from at least a first edge of the plurality of electrode sheets, the first edge is the edge of the electrode sheet opposite to the opening, the plurality of tabs are pasted to form a tab stack, and the tab stack is electrically connected with the pole;

[0008] The tab stack is provided with a bending part for turning a first area of the tab stack to be parallel to the cover plate assembly, the first area of the tab stack is connected to the pole by welding, a first side of the tab stack is provided with a first insulating layer and a second insulating layer, the first side is a side of the tab stack opposite to the pole, the first insulating layer covers at least the first area, the second insulating layer covers at least a connecting area of the first side and the electrode sheet, and the first insulating layer and the second insulating layer are arranged at intervals along the surface of the tab stack, and the bending part is arranged in an interval area between the first insulating layer and the second insulating layer.

[0009] In an optional embodiment of the present application, the thickness of the second insulating layer is greater than the thickness of the first insulating layer.

[0010] In an optional embodiment of the present application, a second side of the tab stack is provided with a third insulating layer, the second side is a side of the tab stack connected to the pole, the third insulating layer covers at least a connecting area of the second side and the electrode sheet, and the third insulating layer is arranged at intervals along the surface of the tab stack and the first area.

[0011] In an optional embodiment of the present application, the interval distance of the first insulating layer and the second insulating layer along the surface of the tab stack is greater than the arc length of the inner arc surface of the bending part.

[0012] In an optional embodiment of the present application, a strip-shaped interval area parallel to the first edge is formed between the first insulating layer and the second insulating layer, and the bending part is arranged to be bent along an axis parallel to the first edge.

[0013] In an optional embodiment of the present application, the width of the strip-shaped interval area is greater than or equal to 3mm and less than or equal to 8mm.

[0014] In an optional embodiment of the present application, the sum of the coverage areas of the first insulating layer and the second insulating layer at least contains all areas of the first side of the tab stack except the strip-shaped interval area.

[0015] In an optional embodiment of the present application, the number of layers of the tabs contained in the tab stack is greater than or equal to 5 layers.

[0016] In an optional embodiment of the present application, the electrode assembly is stacked by a plurality of layers of split electrode sheets, or is wound by a continuous electrode sheet.

[0017] In an optional embodiment of the utility model, the shell is equipped with two opposite openings, the cover plate assembly is equipped with two, two cover plate assemblies are connected to two openings respectively, the tab is led out from two ends of the electrode assembly respectively and is connected with the pole on two cover plate assemblies respectively.

[0018] The technical effect of the utility model lies in that the two insulating layers are respectively kept away from the bending part of the tab, which can effectively prevent the separation of the insulating layer due to the inconsistency of elastic modulus and yield strength in the bending process, avoids the safety risk caused by the adhesion of metal particles or dust and the like foreign matters to the insulating layer, improves the overall safety performance of the battery, in addition, the bending of the tab is more stable without the intervention of the insulating layer, and the safety and reliability are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the front view of the secondary battery provided by the embodiment of the utility model, and the shell is hidden in the drawing;

[0020] Figure 2 It is the A-A sectional view of Figure 1 ;

[0021] Figure 3 It is the I local enlarged view of Figure 2 ;

[0022] Figure 4 It is the structure schematic view when the electrode assembly and the cover plate assembly are welded, provided by the embodiment of the utility model;

[0023] Figure 5 It is the II local enlarged view of Figure 4 . DETAILED DESCRIPTION

[0024] The embodiments of the utility model are described below through specific concrete examples, and the other advantages and effects of the utility model can be easily understood by the person skilled in the art from the content disclosed in the specification. The utility model can also be implemented or applied through another different concrete embodiment, and each detail in the specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the utility model. It should be noted that the following embodiments and the features in the embodiments can be combined with each other without conflict.

[0025] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the utility model in a schematic manner, and only the components related to the utility model are displayed in the drawings without drawing the number, shape and size of the components in actual implementation, the type, number and proportion of each component in actual implementation can be changed arbitrarily, and the component layout type can also be more complex.

[0026] Secondary battery, also known as rechargeable battery or storage battery, is a type of battery that can store energy by charging and release energy when needed. The secondary battery according to the utility model particularly refers to a battery with bundled tabs, such as a square can lithium ion battery. Generally, the multiple tabs are pre-welded into a whole, and then the pre-welded tabs are welded with the pole. In order to prevent the welding slag from causing pollution to the surrounding area, an insulating layer is generally pasted on the welding area of the tab. In addition, in order to prevent the tab root from tearing, an insulating layer is also pasted between the tab root and the electrode sheet. However, when the electrode sheet is loaded into the shell, a bending part is generally formed between the welding area of the tab and the tab root. Since the elastic modulus and yield strength of the insulating layer and the tab are inconsistent during the bending process, the insulating layer and the tab will be separated to a certain extent, causing the insulating layer to be detached. At this time, the adhesive of the insulating layer will correspondingly bond metal particles, dust and other foreign matters, causing safety risks. Therefore, the two insulating layers are spaced apart, and the two insulating layers avoid the bending area of the tab, thereby preventing the insulating layer from being detached and avoiding the safety risks caused by the adhesion of metal particles, dust and other foreign matters.

[0027] The technical scheme of the utility model will be described in detail in combination with specific embodiments as follows:

[0028] Please refer to Figures 1-5 The secondary battery provided by the embodiment of the utility model includes a shell (not shown in the figure), a cover plate assembly 10 and an electrode assembly 20. At least one end of the shell is provided with an opening. The cover plate assembly 10 is connected with the shell and closes the opening. The cover plate assembly 10 is provided with a pole 11. The electrode assembly 20 includes multiple electrode sheets and multiple tabs led out from at least a first edge of the multiple electrode sheets. The first edge is the edge of the electrode sheet opposite to the opening. The multiple tabs are pasted with each other to form a tab stack 21. The tab stack 21 is electrically connected with the pole 11. The tab stack 21 is provided with a bending part 210. The first side of the tab stack 21 is provided with a first insulating layer 211 and a second insulating layer 212. The first insulating layer 211 and the second insulating layer 212 are spaced apart along the surface of the tab stack 21. The first insulating layer 211 and the second insulating layer 212 are respectively arranged away from the bending part 210.

[0029] The two insulating layers of the utility model avoid the bending part 210 of the tab, which can effectively prevent the separation of the insulating layer caused by the inconsistency of the elastic modulus and the yield strength during the bending process, avoid the safety risks caused by the adhesion of metal particles or dust and other foreign matters, and improve the overall safety performance of the battery. In addition, without the interference of the insulating layer, the bending of the tab is more stable, and the safety and reliability are greatly improved.

[0030] Referring to Figure 5 As shown in the optional embodiment of the utility model, the first area 213 of the tab stack 21 is connected with the pole 11 by welding, the first side is the side of the tab stack 21 opposite to the pole 11, and the first insulating layer 211 covers at least the first area 213. It should be understood that after the tab stack 21 is bent, the side opposite to the pole 11 will face the electrode assembly 20, and at this time, the welding slag of the welding area is easy to contact the electrode assembly 20, which causes the risk of short circuit of the electrode assembly 20. Therefore, the first insulating layer 211 is arranged at the position corresponding to the first area 213 on the first side of the tab stack 21, which can effectively isolate the tab stack 21 from the electrode assembly 20 and avoid the pollution of the electrode assembly caused by the welding slag.

[0031] Referring to Figure 5 As shown in the optional embodiment of the utility model, the second insulating layer 212 covers at least the connection area between the tab stack 21 and the electrode sheet. The second insulating layer 212 can improve the structural strength between the tab and the electrode sheet and prevent the tab from tearing. In addition, the welding equipment performs welding from the first side of the tab stack 21, and the area where the first side of the tab stack 21 is connected with the electrode sheet is exposed around the welding area, and the welding slag generated by welding is easy to pollute the tab and the electrode sheet. The second insulating layer 212 is arranged at the connection area between the tab stack 21 and the electrode sheet, which can effectively prevent the welding slag and dust generated during welding from contacting the electrode sheet. In order to further improve the structural strength between the tab and the electrode sheet, the thickness of the second insulating layer 212 can be appropriately increased, for example, the thickness of the second insulating layer 212 can be at least greater than the thickness of the first insulating layer 211.

[0032] Referring to Figure 3 As shown in the optional embodiment of the utility model, the second side of the tab stack 21 is provided with a third insulating layer 214, the second side is the side of the tab stack 21 connected with the pole 11, the third insulating layer 214 covers at least the connection area between the second side and the electrode sheet, and the third insulating layer 214 is arranged in the surface of the tab stack 21 and spaced from the first area 213. The third insulating layer 214 can improve the structural strength between the tab on the second side and the electrode sheet and prevent the tab on this side from tearing. The third insulating layer 214 is arranged in the surface of the tab stack 21 and spaced from the first area 213, which can prevent the third insulating layer 214 from affecting the current flow performance between the tab and the pole 11.

[0033] Referring to Figure 3As shown in an optional embodiment of the present application, the bending part 210 is located in the interval region between the first insulating layer 211 and the second insulating layer 212. It should be noted that in order to prevent the short circuit between the tab and the electrode sheet, the prior art generally covers the entire tab surface with an insulating layer. However, in fact, the bending region of the tab generally has a certain supporting stiffness and a relatively fixed shape, and the bending region and the electrode sheet are isolated by the tab itself. Therefore, the bending region of the tab generally does not short circuit with the electrode sheet. The insulating layer of the bending region is cancelled in the present application, which does not have any adverse effect on the battery performance. At the same time, since the insulating layer of the bending region is cancelled, the delamination phenomenon of the insulating layer can be effectively avoided, thereby improving the safety of the battery. Therefore, the present application actually eliminates the prejudice of the prior art and produces unexpected technical effects.

[0034] Please refer to Figure 3 As shown in an optional embodiment of the present application, the interval distance between the first insulating layer 211 and the second insulating layer 212 along the surface of the tab stack 21 is greater than the arc length of the inner arc surface of the bending part 210. By spacing the first insulating layer 211 and the second insulating layer 212, and ensuring that the interval distance is greater than the arc length of the inner arc surface of the bending part 210, the delamination phenomenon of the insulating layer at the bending part 210 of the tab stack 21 can be effectively avoided. The insulating layer does not directly contact the bending region, thereby reducing the separation problem caused by the inconsistency of the material elastic modulus and yield strength. Since the insulating layer does not cover the bending region, the safety risk caused by the adhesion of foreign matters such as metal particles or dust to the insulating layer is avoided, the internal short circuit risk of the battery is reduced, and the overall safety performance of the battery is improved.

[0035] Please refer to Figure 5 As shown in an optional embodiment of the present application, a strip-shaped interval region 210' parallel to the first edge is formed between the first insulating layer 211 and the second insulating layer 212, and the bending part 210 is arranged along the axis parallel to the first edge to make the first region 213 flip to a state parallel to the cover plate assembly 10. The bending part 210 is arranged along the axis parallel to the first edge, so that the bending process is more accurate and consistent. This accurate bending path ensures the structural stability and reliability of the tab stack 21, reduces the stress concentration and deformation problems that may occur during the bending process, and enhances the overall structural strength of the tab stack 21 through the accurate bending path and the reasonable layout of the insulating layer. This design makes the battery have better anti-deformation ability when subjected to external impact or vibration, thereby improving the service life and reliability of the battery.

[0036] Please refer to Figure 5As shown in an optional embodiment of the utility model, the width of the strip-shaped spacing area 210' is greater than or equal to 3 mm and less than or equal to 8 mm. If the exposed width of the tab is too wide, the insulation risk inside the secondary battery can not be controlled, and if the exposed width of the tab is too narrow, the bending condition of the insulation layer and the bending condition of the tab are inconsistent, and there is a risk of introducing foreign matter. The width of the strip-shaped spacing area 210' in the embodiment is set to be between 3 mm and 8 mm, which can ensure the insulation performance inside the secondary battery while avoiding insulation layer delamination and improving the safety of the battery. In specific embodiments, the width of the strip-shaped spacing area 210' can be, for example, 5 mm.

[0037] Please refer to Figure 5 As shown in an optional embodiment of the utility model, the sum of the coverage areas of the first insulation layer 211 and the second insulation layer 212 at least contains all areas on the first side of the tab stack 21 except the strip-shaped spacing area 210'. By ensuring that the sum of the coverage areas of the first insulation layer 211 and the second insulation layer 212 contains all areas on the first side of the tab stack 21 except the strip-shaped spacing area 210', comprehensive insulation protection of the tab stack 21 can be achieved, effectively preventing the short circuit risk between the tab and the electrode sheet and improving the overall safety performance of the battery. Comprehensive coverage of the insulation layer can effectively prevent contamination of the electrode sheet and the tab by slag and dust, and also prevent the short circuit risk between the tab stack 21 and the electrode sheet, improving the manufacturing quality and reliability of the battery.

[0038] In an optional embodiment of the utility model, the tab stack 21 contains more than or equal to 5 layers of the tab. It should be understood that the more layers of the tab, the greater the difference in the radii of the inner and outer arc surfaces of the bending area, and the more obvious the inconsistency between the elastic modulus and yield strength of the insulation layer and the tab. Therefore, the utility model is particularly suitable for secondary batteries with a large number of tab layers, such as secondary batteries with 5 or more layers of tabs.

[0039] The specific structure of the secondary battery provided by the utility model has no special restrictions on the electrode assembly 20, for example, in some embodiments, the electrode assembly 20 can be formed by stacking multiple layers of split electrode sheets. For example, in other embodiments, the electrode assembly 20 can also be formed by winding a continuous electrode sheet.

[0040] The lead-out mode of the pole 11 of the secondary battery is not specially limited, for example, in some embodiments, the shell is provided with two opposite openings, the cover plate assembly 10 is provided with two, and the two cover plate assemblies 10 are respectively connected to the two openings; the tab is respectively led out from the two ends of the electrode assembly 20 and is respectively connected with the pole 11 on the two cover plate assemblies 10. For another example, in other embodiments, the secondary battery can be provided with only one cover plate assembly 10, and the two poles 11 can be arranged at the two ends of the cover plate assembly 10, or one pole 11 is arranged on the cover plate assembly 10, and the other pole 11 is arranged on the shell.

[0041] In conclusion, the two insulating layers of the utility model are respectively kept away from the bending part of the tab, which can effectively prevent the separation of the insulating layer due to the inconsistent elastic modulus and yield strength in the bending process, avoid the safety risk caused by the adhesion of foreign matters such as metal particles or dust on the insulating layer, and improve the overall safety performance of the battery; in addition, the bending of the tab is more stable without the intervention of the insulating layer, and the safety and reliability are greatly improved.

[0042] The above-mentioned embodiments only exemplarily illustrate the principle and effect of the utility model, and are not used for limiting the utility model. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the utility model should be covered by the claims of the utility model.

[0043] In the description herein, many specific details are provided, such as examples of components and / or methods, to provide a thorough understanding of embodiments of the application. Persons skilled in the art, however, will recognize that embodiments of the application can be practiced without one or more of the specific details. In other instances, well-known structures, materials, or operations are not shown or described in detail in order to avoid obscuring aspects of embodiments of the application.

Claims

1. A secondary battery characterized by comprising: The application relates to a battery, comprising: a shell, at least one end of which is provided with an opening; a cover plate assembly connected with the shell and sealing the opening, the cover plate assembly being provided with a pole column; an electrode assembly comprising a plurality of electrode sheets and a plurality of tab stacks, the plurality of tab stacks being formed by a plurality of tab ears from at least a first edge of the plurality of electrode sheets, the first edge being an edge of the electrode sheets opposite to the opening, the plurality of tab stacks being electrically connected with the pole column; the plurality of tab stacks are provided with a bending part for turning a first area of the plurality of tab stacks to a state parallel to the cover plate assembly, the first area of the plurality of tab stacks being connected with the pole column by welding, the first side of the plurality of tab stacks being provided with a first insulating layer and a second insulating layer, the first side being a side of the plurality of tab stacks opposite to the pole column, the first insulating layer covering at least the first area, the second insulating layer covering at least a connecting area between the first side and the electrode sheets, the first insulating layer and the second insulating layer being spaced apart along a surface of the plurality of tab stacks, and the bending part being located in a spacing area between the first insulating layer and the second insulating layer.

2. The secondary battery according to claim 1, characterized by The second insulating layer has a thickness greater than that of the first insulating layer.

3. The secondary battery according to claim 1, characterized by The second side of the plurality of tab stacks is provided with a third insulating layer, the second side being a side of the plurality of tab stacks connected with the pole column, the third insulating layer covering at least a connecting area between the second side and the electrode sheets, and the third insulating layer being spaced apart from the first area along a surface of the plurality of tab stacks.

4. The secondary battery according to claim 1, characterized by The spacing distance of the first insulating layer and the second insulating layer along the surface of the plurality of tab stacks is greater than the arc length of an inner arc surface of the bending part.

5. The secondary battery according to claim 1, characterized by A strip-shaped spacing area parallel to the first edge is formed between the first insulating layer and the second insulating layer, and the bending part is arranged along an axis parallel to the first edge.

6. The secondary battery according to claim 5, characterized by The width of the strip-shaped spacing area is greater than or equal to 3 mm and less than or equal to 8 mm.

7. The secondary battery according to claim 5, characterized by The sum of the covering areas of the first insulating layer and the second insulating layer contains all areas of the first side of the plurality of tab stacks except the strip-shaped spacing area.

8. The secondary battery according to claim 1, characterized by The plurality of tab stacks contain more than or equal to 5 layers of the tab ears.

9. The secondary battery according to claim 1, characterized by The electrode assembly is stacked by a plurality of split electrode sheets or is wound by a continuous electrode sheet.

10. The secondary battery according to claim 1, characterized by The shell is provided with two opposite openings, the cover plate assembly is provided with two cover plate assemblies, the two cover plate assemblies are respectively connected with the two openings, the tab ears are respectively led out from two ends of the electrode assembly and are respectively connected with the pole columns on the two cover plate assemblies.

Images