Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery, the battery cell comprises a battery cell body, the battery cell body comprises an anode pole piece, a diaphragm and a cathode pole piece which are mutually stacked and wound; the cathode tab is provided with a first welding part and a first extension part, the first welding part is welded to the cathode pole piece, and the first extension part extends from the first welding part to be exposed out of the cathode pole piece in a protruding mode; the anode tab is provided with a second welding part and a second extension part, the second welding part is welded to the anode pole piece, and the second extension part extends from the second welding part and is exposed out of the anode pole piece in a protruding manner; and at least local area of at least one of the first welding part and the second welding part is provided with a mesh hole group. When the winding battery cell disclosed by the utility model is used for acupuncture test, the probability that a test needle is communicated with the cathode tab and the anode tab to form a closed loop can be reduced, so that the situations of fire and explosion caused by thermal runaway of the battery cell are avoided, and the safety performance is improved.

Description

Technical Field

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

[0002] When an electric vehicle encounters an accident during driving, its lithium-ion battery is easily punctured by metal and an internal short circuit occurs, which may lead to smoking, fire, and ultimately thermal runaway, posing a serious threat to the life and property safety of the driver and passengers. Therefore, with the rapid development of electric vehicles, the safety issues of lithium batteries have gradually attracted people's attention.

[0003] During the production process of lithium-ion batteries, a needle puncture test is usually carried out, that is, a puncture needle is used to penetrate the wound core to simulate an internal short circuit for testing, and to confirm whether the battery smokes or catches fire to detect the safety performance of the battery.

[0004] However, during the needle puncture test, when the puncture needle penetrates the anode tab, it is easy to penetrate the cathode tab at the same time, so that the cathode tab, the puncture needle, and the anode tab are connected in sequence to form a closed loop, resulting in an increased current transmission, causing thermal runaway of the battery cell, and then causing fire and explosion, affecting the safety of the needle puncture test. Summary of the Utility Model

[0005] The main object of the utility model is to propose a battery cell, aiming to solve the technical problem that during the needle puncture test of the current battery cell, the steel needle is easy to form a closed loop between the cathode and the anode due to simultaneously penetrating the anode tab and the cathode tab, resulting in thermal runaway of the battery cell, causing fire and explosion.

[0006] To achieve the above object, the utility model proposes a battery cell, which includes:

[0007] A battery cell body, the battery cell body includes an anode electrode sheet, a separator, and a cathode electrode sheet that are stacked and wound with each other;

[0008] A cathode tab, the cathode tab has a first welding part and a first extension part, the first welding part is welded to the cathode electrode sheet, and the first extension part extends from the first welding part and protrudes outside the cathode electrode sheet;

[0009] An anode tab, the anode tab has a second welding part and a second extension part, the second welding part is welded to the anode electrode sheet, and the second extension part extends from the second welding part and protrudes outside the anode electrode sheet;

[0010] At least a partial area of at least one of the first welding part and the second welding part is provided with a mesh hole group.

[0011] In some embodiments, a first mesh hole group is provided at at least a partial area of the first welding part, and the first mesh hole group at least covers the middle area of the first welding part in the height direction of the battery cell body.

[0012] In some embodiments, the ratio of the width of the first mesh hole group to the width of the cathode tab is 80% - 100%; and / or,

[0013] the ratio of the height of the first mesh hole group to the height of the cathode tab is 40% - 60%.

[0014] In some embodiments, a second mesh hole group is provided at at least a partial area of the second welding part, and the second mesh hole group at least covers the middle area of the second welding part in the height direction of the battery cell body.

[0015] In some embodiments, the ratio of the width of the second mesh hole group to the width of the anode tab is 80% - 100%; and / or,

[0016] the ratio of the height of the second mesh hole group to the height of the anode tab is 40% - 60%.

[0017] In some embodiments, the mesh holes in the mesh hole group are arranged in a matrix; and / or,

[0018] the aperture of the mesh holes in the mesh hole group is 0.5 mm - 1.5 mm.

[0019] In some embodiments, a first flame retardant layer is provided on the surface of the first welding part facing away from the cathode tab, and the first flame retardant layer at least covers the first mesh hole group.

[0020] In some embodiments, a second flame retardant layer is provided on the surface of the second welding part facing away from the anode tab, and the second flame retardant layer at least covers the second mesh hole group.

[0021] In some embodiments, there is one cathode tab, and the cathode tab is located at the middle position in the winding direction of the cathode tab; and / or,

[0022] there are two anode tabs, and the two anode tabs are respectively located on both sides in the winding direction of the anode tab.

[0023] The present invention further provides a battery, which includes a housing and the battery cell as described above, and the battery cell is disposed in the housing.

[0024] When the wound battery cell of the present utility model is subjected to a needle penetration test, the test needle penetrates the battery cell body and passes through the first welding part of the anode tab. Even if the test needle also penetrates the second welding part of the cathode tab when it stabs the cathode tab at the same time, since at least a partial area of at least one of the first welding part and the second welding part is provided with a mesh hole group, the contact between the test needle and the cathode tab and / or the anode tab can be reduced, thereby reducing the probability that the test needle connects the cathode tab and the anode tab to form a closed loop, and further avoiding the situation of thermal runaway of the battery cell, which may cause fire and explosion, and improving the safety performance. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of the cathode tab and the anode tab of the battery cell in an embodiment of the present utility model;

[0026] Figure 2 It is a schematic structural diagram of the battery cell in an embodiment of the present utility model;

[0027] Description of the reference numerals in the drawings:

[0028] Label Name Label Name 100 Cell body 300 Anode tab 110 Anode plate 310 Second welding part 120 Cathode plate 320 Second extension part 200 Cathode tab 10 Mesh hole group 210 First welding part 11 First mesh hole group 220 First extension part 12 Second mesh hole group

[0029] The realization, functional characteristics and advantages of the object of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0030] Next, the solutions in the embodiments of the present utility model will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present utility model.

[0031] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0032] 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.

[0033] 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 ability of those of ordinary skill in the art to implement. 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.

[0034] An embodiment of the present utility model provides a battery cell. Referring to Figure 1 and Figure 2 , the battery cell includes:

[0035] A battery cell body 100, which includes an anode electrode sheet 110, a separator, and a cathode electrode sheet 120 that are stacked and wound with each other;

[0036] A cathode tab 200, which has a first welding portion 210 and a first extension portion 220. The first welding portion 210 is welded to the cathode electrode sheet 120, and the first extension portion 220 extends from the first welding portion 210 and protrudes outside the cathode electrode sheet 120;

[0037] An anode tab 300, which has a second welding portion 310 and a second extension portion 320. The second welding portion 310 is welded to the anode electrode sheet 110, and the second extension portion 320 extends from the second welding portion 310 and protrudes outside the anode electrode sheet 110;

[0038] A mesh hole group 10 is provided at least in a partial area of at least one of the first welding portion 210 and the second welding portion 310.

[0039] The battery cell involved in this embodiment includes a battery cell body 100, a cathode tab 200, and an anode tab 300. The battery cell body 100 includes an anode electrode sheet 110, a separator, and a cathode electrode sheet 120. Among them, the anode electrode sheet 110, the separator, and the cathode electrode sheet 120 are stacked in sequence and wound, and after winding, the battery cell body 100 is correspondingly formed.

[0040] Both the cathode tab 200 and the anode tab 300 are strip-shaped, and can also be called linear. The first welding portion 210 of the cathode tab 200 and the first extension portion 220 are integrally formed. Before winding, the cathode electrode sheet 120 is in a flat state. The cathode tab 200 is located on one side of the cathode electrode sheet 120, and is welded to the cathode electrode sheet 120 through its first welding portion 210, while its first extension portion 220 extends from the first welding portion 210 and protrudes outside the cathode electrode sheet 120. Optionally, the height of the first welding portion 210 is less than or equal to the height of the cathode electrode sheet 120, and the height of the first extension portion 220 is less than the height of the first welding portion 210.

[0041] The second welding portion 310 of the anode tab 300 and the second extension portion 320 are integrally formed. Before winding, the anode electrode sheet 110 is in a flat state. The anode tab 300 is located on one side of the anode electrode sheet 110, and is welded to the anode electrode sheet 110 through its second welding portion 310, while its second extension portion 320 extends from the second welding portion 310 and protrudes outside the anode electrode sheet 110. Optionally, the height of the second welding portion 310 is less than or equal to the height of the anode electrode sheet 110, and the height of the second extension portion 320 is less than the height of the second welding portion 310.

[0042] Among them, the mesh hole group 10 can be provided at at least a partial area of the first welding portion 210, or at at least a partial area of the second welding portion 310, or at least a partial area of both the first welding portion 210 and the second welding portion 310. The mesh hole group 10 is formed by combining a plurality of mesh holes. The number and arrangement form of the mesh holes in the mesh hole group 10 are not limited in this embodiment. Among them, the mesh holes can be circular holes, polygonal holes, etc. The function of the mesh hole group 10 is to avoid the test needle C during the needle-punching test, so that the tip of the test needle C can pass through. When the test needle C is needle-punched at the mesh hole group 10 of the tab, due to passing through the mesh holes, the contact with the tab will be greatly reduced.

[0043] When the battery cell of the present utility model is subjected to a needle-punching test, the test needle C needles the battery cell body 100 and will penetrate the first welding portion 210 of the anode tab 300. Even if the test needle C simultaneously stabs the cathode tab 200 and penetrates the second welding portion 310 of the cathode tab 200, since the mesh hole group 10 is provided at at least a partial area of at least one of the first welding portion 210 and the second welding portion 310, the contact between the test needle C and the cathode tab 200 and / or the anode tab 300 can be reduced, thereby reducing the probability that the test needle C connects the cathode tab 200 and the anode tab 300 to form a closed circuit, and further avoiding the situation of thermal runaway of the battery cell causing fire and explosion, and improving the safety performance.

[0044] In some embodiments, referring to Figure 1 and Figure 2 , at least a partial area of the first welding part 210 is provided with a first mesh hole group 11, and the first mesh hole group 11 at least covers the middle area of the first welding part 210 in the height direction of the battery cell body 100. During the needle puncture test of the battery, the test needle C usually punctures the middle position of the battery cell body 100. In this embodiment, mesh holes are provided at the middle position of the cathode tab 200 corresponding to the battery cell body 100. Specifically, at least a partial area of the first welding part 210 is provided with the first mesh hole group 11, and the first mesh hole group 11 at least covers the middle area of the first welding part 210 in the height direction of the battery cell body 100. Thus, when the test needle C punctures the battery cell body 100 and punctures the cathode tab 200, it will correspondingly puncture the middle area of the first welding part 210 in the height direction of the battery cell body 100. Since this area is covered with the first mesh hole group 11, the mesh holes of the first mesh hole group 11 will avoid the test needle C to allow the tip of the test needle C to pass through, thereby reducing the contact between the test needle C and the cathode tab 200, reducing the probability that the test needle C connects the cathode tab 200 and the anode tab 300 to form a closed circuit, and further avoiding the situation of thermal runaway of the battery cell causing fire and explosion, and improving the safety of the needle puncture test.

[0045] In some embodiments, the ratio of the width of the first mesh hole group 11 to the width of the cathode tab 200 is 80% - 100%; that is, the ratio of the width of the first mesh hole group 11 to the width of the cathode tab 200 can be set within the range of 80% - 100%. For example, the ratio of the width of the first mesh hole group 11 to the width of the cathode tab 200 can be set to 80%, 90% or 100%. It should be noted that when the ratio of the width of the first mesh hole group 11 to the width of the cathode tab 200 is 100%, the mesh holes on both sides of the first mesh hole group 11 correspondingly contact the two edge lines in the width direction of the cathode tab 200. And / or, in some embodiments, the ratio of the height of the first mesh hole group 11 to the height of the cathode tab 200 is 40% - 60%. That is, the ratio of the height of the first mesh hole group 11 to the height of the cathode tab 200 can be set within the range of 40% - 60%. For example, the ratio of the height of the first mesh hole group 11 to the height of the cathode tab 200 can be set to 40%, 50% or 60%. As an example, the height of the cathode tab 200 is 100 mm, the height of the first welding part 210 is 75 mm, the height of the first extension part 220 is 25 mm, the height of the first mesh hole group 11 is 50 mm, and the ratio of the height of the first mesh hole group 11 to the height of the cathode tab 200 is 50%.

[0046] In some embodiments, referring to Figure 1 and Figure 2, at least a partial area of the second welding part 310 is provided with a second mesh hole group 12, and the second mesh hole group 12 at least covers the middle area of the second welding part 310 in the height direction of the battery cell body 100. In this embodiment, on the basis that mesh holes are provided at the middle position of the cathode tab 200 corresponding to the battery cell body 100, mesh holes are also provided at the middle position of the anode tab 300 corresponding to the battery cell body 100. Specifically, a second mesh hole group 12 is provided at least in a partial area of the second welding part 310, and the second mesh hole group 12 at least covers the middle area of the second welding part 310 in the height direction of the battery cell body 100. In this way, when the test needle C punctures the battery cell body 100 and punctures the anode tab 300, it will correspondingly puncture the middle area of the second welding part 310 in the height direction of the battery cell body 100. Since this area is covered with the second mesh hole group 12, the mesh holes of the second mesh hole group 12 will avoid the test needle C to allow the tip of the test needle C to pass through, thereby reducing the contact between the test needle C and the anode tab 300, and further reducing the probability that the test needle C connects the cathode tab 200 and the anode tab 300 to form a closed loop, and improving the safety of the puncture test.

[0047] In some embodiments, the ratio of the width of the second mesh hole group 12 to the width of the anode tab 300 is 80% - 100%; that is, the ratio of the width of the second mesh hole group 12 to the width of the anode tab 300 can be set within the range of 80% - 100%. For example, the ratio of the width of the second mesh hole group 12 to the width of the anode tab 300 can be set to 80%, 90% or 100%. It should be noted that when the ratio of the width of the second mesh hole group 12 to the width of the anode tab 300 is 100%, the mesh holes on both sides of the second mesh hole group 12 correspondingly contact the two side edge lines in the width direction of the anode tab 300. And / or, in some embodiments, the ratio of the height of the second mesh hole group 12 to the height of the anode tab 300 is 40% - 60%. That is, the ratio of the height of the second mesh hole group 12 to the height of the anode tab 300 can be set within the range of 40% - 60%. For example, the ratio of the height of the second mesh hole group 12 to the height of the anode tab 300 can be set to 40%, 50% or 60%. As an example, the height of the anode tab 300 is 100 mm, the height of the second welding part 310 is 75 mm, the height of the second extension part 320 is 25 mm, the height of the second mesh hole group 12 is 50 mm, and the ratio of the height of the second mesh hole group 12 to the height of the anode tab 300 is 50%.

[0048] In some embodiments, referring to Figure 1 and Figure 2, the mesh holes in the mesh hole group 10 are arranged in a matrix; specifically, the mesh holes in the mesh hole group 10 have multiple rows and multiple columns, adopting a matrix arrangement layout, and the hole positions are densely arranged. During the acupuncture test, when the test needle C pierces the area where the mesh hole group 10 is located on the tab, the test needle C can pass through at least one mesh hole in the mesh hole group 10, thereby reducing the contact between the test needle C and the tab. Among them, the distance between any adjacent mesh holes in the mesh hole group 10 is the same, and as for the specific value of the distance, it can be set with reference to the size specification of the tab. And / or, in some embodiments, the aperture of the mesh holes in the mesh hole group 10 is 0.5 mm to 1.5 mm. Specifically, the aperture of the mesh holes in the mesh hole group 10 can be set within the range of 0.5 mm to 1.5 mm. For example, the aperture of the mesh holes in the mesh hole group 10 can be set to 0.5 mm, 1 mm or 1.5 mm. Optionally, the aperture of the mesh holes in the mesh hole group 10 can be set with reference to the size of the needle tip of the test needle C. For example, when the needle tip of the test needle C is small, the aperture of the mesh holes in the mesh hole group 10 can be set to be small; when the needle tip of the test needle C is large, the aperture of the mesh holes in the mesh hole group 10 can be set to be large. This is only exemplary and not restrictive.

[0049] In some embodiments, a first flame retardant layer is provided on the side of the first welding portion 210 facing away from the cathode electrode sheet 120, and the first flame retardant layer covers at least the first mesh hole group 11. During the acupuncture test, when the test needle C pierces the area where the first mesh hole group 11 is located on the cathode tab 200, through the interval of the provided first flame retardant layer, the contact between the test needle C and the cathode tab 200 can be reduced, thereby avoiding the situation of thermal runaway of the battery cell causing fire and explosion; and, even if the battery cell has a thermal runaway, the first flame retardant layer still has a flame retardant effect, which can avoid fire or reduce the burning degree during a fire. Among them, the first flame retardant layer can be formed by coating a flame retardant on the first welding portion 210, and as for the flame retardant used, it can be referred to the common types of flame retardants on the market as long as it is suitable for the battery.

[0050] In some embodiments, a second flame retardant layer is provided on the side of the second welding portion 310 facing away from the anode electrode sheet 110, and the second flame retardant layer covers at least the second mesh hole group 12. During acupuncture, when the test needle C pierces the area where the second mesh hole group 12 is located on the anode tab 300, through the interval of the provided second flame retardant layer, the contact between the test needle C and the anode tab 300 can be reduced, thereby avoiding the situation of thermal runaway of the battery cell causing fire and explosion; and, even if the battery cell has a thermal runaway, the second flame retardant layer still has a flame retardant effect, which can avoid fire or reduce the burning degree during a fire. Among them, the second flame retardant layer can be formed by coating a flame retardant on the second welding portion 310, and as for the flame retardant used, it can be referred to the common types of flame retardants on the market as long as it is suitable for the battery.

[0051] In some embodiments, with reference to Figure 1 and Figure 2 , there is one cathode tab 200, and the cathode tab 200 is located at the middle position in the winding direction of the cathode plate 120; specifically, one cathode tab 200 is provided and arranged at the middle position in the winding direction of the cathode plate 120. After the anode plate 110, the separator, and the cathode plate 120 are stacked in sequence and wound, the cathode tab 200 is located in the middle layer of the winding layer of the battery cell body 100. And / or, in some embodiments, with reference to Figure 1 and Figure 2 , there are two anode tabs 300, and the two anode tabs 300 are respectively located at both sides of the anode plate 110 in the winding direction. Specifically, two anode tabs 300 are provided and respectively arranged at both sides of the anode plate 110 in the winding direction. After the anode plate 110, the separator, and the cathode plate 120 are stacked in sequence and wound, one anode tab 300 is located in the innermost layer of the winding layer of the battery cell body 100, and the other anode tab 300 is located in the outermost layer of the battery cell body 100. Wherein, the battery cell body 100 has a first end and a second end which are oppositely arranged, the first extension part 220 of the cathode tab 200 extends out from the first end of the battery cell body 100, and the second extension part 320 of the anode tab 300 extends out from the second end of the battery cell body 100. Exemplarily, the first end of the battery cell body 100 can be its upper end, and the second end of the battery cell body 100 can be its lower end.

[0052] As another alternative implementation, it is also possible that there is one anode tab 300, and the anode tab 300 is located at the middle position in the winding direction of the anode plate 110; there are two cathode tabs 200, and the two cathode tabs 200 are respectively located at both sides of the cathode plate 120 in the winding direction. After the anode plate 110, the separator, and the cathode plate 120 are stacked in sequence and wound, the anode tab 300 is located in the middle layer of the winding layer of the battery cell body 100, one of the cathode tabs 200 is located in the innermost layer of the winding layer of the battery cell body 100, and the other cathode tab 200 is located in the outermost layer of the winding layer of the battery cell body 100.

[0053] The embodiment of the present utility model also provides a battery, which includes a housing and the battery cell as described in the foregoing embodiments, and the battery cell is disposed in the housing. The specific structure of the battery cell refers to the above embodiments. Since this battery adopts all the technical solutions of the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated herein one by one. Among them, the battery can be a lithium battery.

[0054] 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: include: A battery cell body, the battery cell body comprising an anode electrode sheet, a separator and a cathode electrode sheet stacked and wound one on another; A cathode tab, the cathode tab having a first welding portion and a first extension portion, the first welding portion being welded to the cathode electrode piece, and the first extension portion extending from the first welding portion and protruding outside the cathode electrode piece; an anode tab, the anode tab having a second welding portion and a second extension portion, the second welding portion being welded to the anode pole piece, and the second extension portion extending from the second welding portion and protruding outside the anode pole piece; A mesh hole group is provided at least partially in at least one of the first welding portion and the second welding portion.

2. The battery cell according to claim 1, characterized in that: A first mesh hole group is provided at least partially in the first welding portion, and the first mesh hole group covers at least a middle area of ​​the first welding portion in the height direction of the battery cell body.

3. The battery cell according to claim 2, characterized in that: The ratio of the width of the first mesh hole group to the width of the cathode tab is 80% to 100%; and / or, The height of the first mesh hole group accounts for 40% to 60% of the height of the cathode tab.

4. The battery cell according to claim 2, characterized in that: A second mesh hole group is provided at least partially in the second welding portion, and the second mesh hole group at least covers a middle area of ​​the second welding portion in the height direction of the battery cell body.

5. The battery cell according to claim 4, characterized in that: The ratio of the width of the second mesh hole group to the width of the anode tab is 80% to 100%; and / or, The height of the second mesh hole group accounts for 40% to 60% of the height of the anode tab.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The mesh holes in the mesh hole group are arranged in a matrix; and / or, The mesh holes in the mesh hole group have a hole diameter of 0.5 mm to 1.5 mm.

7. The battery cell according to any one of claims 2 to 5, characterized in that: A first flame retardant layer is provided on a side of the first welding portion facing away from the cathode electrode sheet, and the first flame retardant layer at least covers the first mesh hole group.

8. The battery cell according to claim 4 or 5, characterized in that: A second flame retardant layer is provided on a side of the second welding portion facing away from the anode electrode sheet, and the second flame retardant layer at least covers the second mesh hole group.

9. The battery cell according to any one of claims 1 to 5, characterized in that: The cathode tab is provided with one, and the cathode tab is located in the middle of the winding direction of the cathode plate; and / or, There are two anode tabs, and the two anode tabs are respectively located at two sides of the winding direction of the anode electrode sheet.

10. A battery, characterized in that: The invention comprises a shell and the battery cell according to any one of claims 1 to 9, wherein the battery cell is arranged in the shell.

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