Battery cell

Abstract

The utility model discloses a battery cell, which comprises a battery cell main body and a tab, the tab comprises a first connecting part, a fusing part and a second connecting part which are connected in sequence, the sectional area of the first connecting part and the sectional area of the second connecting part are both larger than the sectional area of the fusing part, the first connecting part is connected with the battery cell main body, and the second connecting part is used for being connected with a pole. The distance between the fusing part and the battery cell main body is L1 on a connecting path of the tab and the battery cell main body, and L1 is greater than or equal to 5mm and less than or equal to 20mm. According to the utility model, as the tab is connected with the battery cell main body, heat transfer can be carried out between the tab and the battery cell main body, and the fusing part of the tab can generate larger heat during short circuit and is easy to damage the battery cell main body, the distance L1 between the fusing part and the battery cell main body is kept between 5 mm and 20 mm on the connecting path of the tab and the battery cell main body; therefore, the distance between the fusing part of the tab and the battery cell main body is not too close, and the battery cell main body is prevented from being damaged by heat of the fusing part.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a battery cell. BACKGROUND

[0002] At present, since lithium ion power battery realizes commercialization, because it has light weight, high voltage, small size, no memory effect, high specific energy, long cycle life and environmental friendly and many advantages, it is rapidly widely used in various electric equipment.

[0003] In order to ensure the safety of battery, the conventional battery will be provided with a fuse part at the tab of the battery cell, when short circuit, the short circuit current is greater than the fuse current of the fuse part, so that the fuse part is fused, and the connection with the battery cell main body is cut off.

[0004] However, in the battery cell, since the battery cell main body is connected with the tab, the heat of the fuse part of the tab will be transferred to the battery cell main body, if the fuse part of the tab is too close to the battery cell main body, the heat of the fuse part is easy to damage the battery cell main body. SUMMARY

[0005] The primary object of the utility model is to provide a battery cell to avoid the heat of the fuse part on the tab from damaging the battery cell main body.

[0006] In order to solve the above technical problem, the utility model provides the following technical scheme:

[0007] A battery cell, comprising a battery cell main body and a tab, the tab comprises a first connecting part, a fuse part and a second connecting part connected in sequence, and the cross-sectional area of the first connecting part and the second connecting part is greater than the cross-sectional area of the fuse part, the first connecting part is connected with the battery cell main body, the second connecting part is used for connecting with a pole, and the distance between the fuse part and the battery cell main body on the connecting path of the tab and the battery cell main body is L1, wherein 5mm≤L1≤20mm.

[0008] The battery cell of the utility model embodiment has the beneficial effects compared with the prior art:

[0009] In the utility model, since the tab is connected with the battery cell main body, heat can be transferred between the two, and the fuse part of the tab will generate a large amount of heat when short circuit, which is easy to damage the battery cell main body, so the distance L1 between the fuse part and the battery cell main body on the connecting path of the tab and the battery cell main body is kept between 5-20mm, so that the distance between the fuse part of the tab and the battery cell main body is not too close, avoiding the heat of the fuse part from damaging the battery cell main body. BRIEF DESCRIPTION OF DRAWINGS

[0010] Fig. 1is a front view of the battery cell of the embodiment of the utility model;

[0011] Fig. 2 is a size schematic view of the battery cell of the embodiment of the utility model;

[0012] Fig. 3 is a side view of the battery cell of the embodiment of the utility model;

[0013] Fig. 4 is a relationship schematic view of the insulating film and the tab of the embodiment of the utility model.

[0014] In the figure, 1, battery cell main body;2, tab;21, first connecting part;22, fuse part;23, second connecting part;3, insulating film. Specific implementation

[0015] The specific implementation of the utility model is described in further detail below in combination with the drawings and embodiments. The following embodiments are used to illustrate the utility model, but are not used to limit the scope of the utility model.

[0016] In the description of the utility model, it should be understood that the phrase "comprising" used in the utility model specification means that the features, integers, steps, operations, parts and / or assemblies exist, but does not exclude the existence or addition of one or more other features, integers, steps, operations, parts, assemblies and / or their groups. It should be understood that when we call the part is "connected" to another part, it can be directly connected to other parts, or there can be intermediate parts. The phrase "and / or" used here includes all or any unit and all combinations of one or more associated listed items.

[0017] As Figs. 1 to 4 The utility model relates to a kind of battery cell, including battery cell main body 1 and tab 2, the tab 2 includes sequentially connected first connecting part 21, fuse part 22 and second connecting part 23, and the cross-sectional area of the first connecting part 21 and the second connecting part 23 is all greater than the cross-sectional area of the fuse part 22, the first connecting part 21 is connected with the battery cell main body 1, the second connecting part 23 is used to be connected with pole, in the connection path of tab 2 and battery cell main body 1, the distance between the fuse part 22 and the battery cell main body 1 is L1, wherein, 5mm≤L1≤20mm.

[0018] In the utility model, since the tab 2 is connected with the battery core body 1, the heat can be transferred between the two, and the fuse part 22 of the tab 2 generates a large amount of heat when short-circuiting, which is easy to cause damage to the battery core body 1, therefore, the distance L1 between the fuse part 22 and the battery core body 1 is kept between 5-20mm on the connecting path of the tab 2 and the battery core body 1, so that the distance between the fuse part 22 of the tab 2 and the battery core body 1 is not too close, avoiding the heat of the fuse part 22 from damaging the battery core body 1.

[0019] In the embodiment, the inside of the battery core body 1 has an active material layer, and the distance between the fuse part 22 and the active material layer in the battery core body 1 is L2 on the connecting path of the tab 2 and the battery core body 1, wherein 6.5mm≤L2≤21.5mm.

[0020] On the connecting path of the tab 2 and the battery core body 1, the distance L2 between the fuse part 22 and the active material layer in the battery core body 1 is kept between 6.5-21.5mm, on the one hand, the fuse part 22 is not too close to the active material layer of the battery core body 1, and the temperature difference between the active material layer close to the fuse part 22 and the active material layer far from the fuse part 22 is not too large, so that the local resistance of the battery core body 1 does not differ, the lithium insertion is not uneven, the aging state is different, and the like, and the fuse part 22 is prevented from overheating to cause partial inactivation of the active material, that is, the ability to insert and extract lithium ions is lost, so that lithium precipitation, black spots and the like are caused.

[0021] In the embodiment, the inside of the battery core body 1 has a tab glue, and the distance between the fuse part 22 and the tab glue is L3 on the connecting path of the tab 2 and the battery core body 1, wherein 7mm≤L3≤22mm.

[0022] The tab glue is made of PVDF and Al2O3, so the tab glue also has certain high-temperature resistance, but the instantaneous temperature when the fuse part 22 is fused is also high, and the melting point can reach 660 degrees, so when the distance between the fuse part 22 and the tab glue is too close on the connecting path of the tab 2 and the battery core body 1, the tab glue will be ablated and fail, causing short circuit between the positive electrode foil and the negative electrode material area, and greatly increasing the risk of thermal runaway of the battery core body 1, therefore, the distance L3 between the fuse part 22 and the tab glue in the battery core body 1 is kept between 7-22mm to ensure the performance of the battery core body 1.

[0023] In the embodiment, the inside of the battery core body 1 has a diaphragm, and the distance between the fuse part 22 and the diaphragm is L4 on the connecting path of the tab 2 and the battery core body 1, wherein 5mm≤L4≤20mm.

[0024] Since the diaphragm in the cell body 1 is not temperature resistant, when the fuse portion 22 is close to the diaphragm on the connecting path of the tab 2 and the cell body 1, the diaphragm is easy to be ablated, thereby causing the short circuit of the positive electrode foil and the negative electrode material area, and greatly increasing the risk of thermal runaway of the cell body 1. Therefore, the distance L4 between the fuse portion 22 and the tab rubber in the cell body 1 is kept between 5-20mm to ensure the performance of the cell body 1.

[0025] In the embodiment, the cell further comprises an insulating film 3, and at least one side of the tab 2 in the first direction is provided with the insulating film 3, so as to protect the tab 2.

[0026] Preferably, the insulating film 3 covers the area of the fuse portion 22 of the tab 2, so as to protect the fuse portion 22 from corrosion of the electrolyte or other impurities and ensure the accuracy of the fuse threshold of the fuse portion 22.

[0027] Further, the insulating film 3 extends to the area of the first connecting portion 21 and / or the area of the second connecting portion 23.

[0028] Specifically, the insulating film 3 extends to the area of the first connecting portion 21, that is, the insulating film 3 extends to the root of the tab 2, so as to further prevent the tab 2 from being torn, and then the insulating film 3 extends to the area of the second connecting portion 23, that is, the insulating film 3 extends to the area of the welding of the tab 2 and the pole, so as to prevent the area of the welding of the tab 2 and the pole from being corroded.

[0029] In the embodiment, the distance between the two sides of the insulating film 3 in the second direction is W1, the distance between the two sides of the tab 2 in the second direction is W2, and 1.1≤W1 / W2≤1.5, wherein the second direction is perpendicular to the first direction.

[0030] That is, the ratio of the width of the insulating film 3 to the width of the tab 2 is between 1.1-1.5, so the width of the insulating film 3 can be greater than the width of the tab 2, so that the insulating film 3 can comprehensively protect the tab 2, avoid the tab 2 from being broken and corroded, and at the same time, the width of the insulating film 3 will not be too large to occupy too much space.

[0031] It should be noted that the first direction is the thickness direction of the tab 2, and the second direction is the width direction of the tab 2.

[0032] In an embodiment, the opposite two sides of the tab 2 are both covered with the insulating film 3, so as to more comprehensively protect the tab 2 and prevent the tab 2 from being torn and corroded.

[0033] Preferably, one side of the tab 2 in the first direction is a welding surface, and a welding area is arranged on the welding surface, and the other side of the tab 2 in the first direction is not covered with the insulating film 3 in the area corresponding to the welding area.

[0034] At present, when the insulating film 3 is assembled, a layer of insulating film 3 is first attached to the side of the tab 2 away from the welding surface, and then the tab 2 is welded, and after the welding is completed, a layer of insulating film 3 is attached to the welding surface of the tab 2, thereby completing the attachment of the insulating film 3 to both sides of the tab 2 in the first direction. However, since the side of the tab 2 away from the welding surface is attached with the insulating film 3, it is easy to blow a hole during welding, resulting in poor welding of the tab 2, so the insulating film 3 in the area corresponding to the welding area on the side of the tab 2 away from the welding surface needs to be hollowed out.

[0035] In the embodiment, the distance between the two sides of the tab 2 in the first direction is T1, 0.004mm≤T1≤0.02mm, the resistivity of the tab 2 is p, 1.5*10^-8Ω·m≤p≤3*10^-8Ω·m, and on the connection path of the tab 2 and the main body 1 of the battery cell, the distance between the end close to the first connection part 21 and the end away from the first connection part 21 of the fuse part 22 is L5, 2mm≤L5≤8mm.

[0036] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, without departing from the technical principles of the present application, a number of improvements and substitutions can be made, and these improvements and substitutions should also be considered as the protection range of the present application.

Claims

1. A battery cell, characterized in that, The device includes a battery cell body and a tab. The tab includes a first connecting part, a fusible part, and a second connecting part connected in sequence. The cross-sectional areas of the first connecting part and the second connecting part are both larger than the cross-sectional area of ​​the fusible part. The first connecting part is connected to the battery cell body, and the second connecting part is used to connect to the terminal post. On the connection path between the tab and the battery cell body, the distance between the fusible part and the battery cell body is L1, where 5mm≤L1≤20mm.

2. The battery cell according to claim 1, characterized in that, The battery cell body has an active material layer inside. On the connection path between the electrode and the battery cell body, the distance between the fuse part and the active material layer is L2, where 6.5mm≤L2≤21.5mm.

3. The battery cell according to claim 1, characterized in that, The battery cell body has an internal tab adhesive. On the connection path between the tab and the battery cell body, the distance between the fused part and the tab adhesive is L3, where 7mm≤L3≤22mm.

4. The battery cell according to claim 1, characterized in that, The cell body has a diaphragm inside. On the connection path between the tab and the cell body, the distance between the fuse part and the diaphragm is L4, where 5mm≤L4≤20mm.

5. The battery cell according to claim 1, characterized in that, It also includes an insulating film, which is provided on at least one side of the electrode in the first direction.

6. The battery cell according to claim 5, characterized in that, The insulating film covers the area of ​​the fused portion of the electrode.

7. The battery cell according to claim 6, characterized in that, The insulating film extends to the region of the first connection portion and / or the region of the second connection portion.

8. The battery cell according to claim 5, characterized in that, The distance between the two sides of the insulating film in the second direction is W1, and the distance between the two sides of the electrode in the second direction is W2, wherein 1.1≤W1 / W2≤1.5, and the second direction is perpendicular to the first direction.

9. The battery cell according to claim 5, characterized in that, One side of the electrode tab in the first direction is a welding surface, and a welding area is provided on the welding surface. The area on the other side of the electrode tab in the first direction corresponding to the welding area is not covered by the insulating film.

10. The battery cell according to any one of claims 1-9, characterized in that, The distance between the two sides of the electrode in the first direction is T1, 0.004mm≤T1≤0.02mm, the resistivity of the electrode is ρ, 1.5*10^-8Ω·m≤ρ≤3*10^-8Ω·m, and the distance between the end of the fuse part near the first connection part and the end away from the first connection part on the connection path between the electrode and the battery cell body is L5, 2mm≤L5≤8mm.

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