Battery cell and steel shell battery

Abstract

The utility model discloses a battery cell and a steel shell battery, wherein the battery cell comprises a pole piece and a battery core, the tab comprises a tab body and tab glue, the tab body comprises a first section, a second section and a third section, one end of the first section is arranged on the pole piece, the other end of the first section is connected with the second section, and one end, far away from the first section, of the second section is connected with the third section; the first section is arranged in the shell, the third section is arranged outside the shell, and the second section is arranged in the through hole; tab glue is arranged around the tabs and is used for blocking the through holes. According to the utility model, the tab glue is arranged around the tab, and when the tab directly penetrates through the through hole in the shell of the steel shell battery, the through hole is blocked by the tab glue, so that the battery can be packaged, and the part of the tab, which is positioned on the outer surface of the shell, can be directly connected with electric equipment without welding extra structures such as a pole or a connecting piece; and the short circuit risk caused by welding is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium-ion batteries, in particular to a battery core and a steel-shell battery. Background Art

[0002] Due to the characteristics of high energy density, small footprint, long cycle life and low environmental pollution, lithium batteries are in increasing demand in electric bicycles, communications, power vehicles, electricity, data centers and other fields. As a result, the market has increasingly higher requirements for the energy density and charging speed of lithium-ion batteries. Conventional soft-pack structures can no longer meet customer needs.

[0003] Some battery manufacturers have introduced steel-cased batteries, which reduce the width of the top seal and the space wasted by the folded edges, thereby increasing the volumetric energy density. However, because the steel-cased battery shell is conductive, it is usually necessary to add connecting plates and poles to the shell. A PFA layer is required between the connecting plates and the shell for insulation. However, the additional connecting plates and poles require multiple welding processes, which risks breaking through the PFA layer and causing a short circuit. Utility Model Content

[0004] The main purpose of the utility model is to provide a battery core, aiming to solve the problem that short circuits are easily caused during welding of existing steel shell batteries.

[0005] To achieve the above-mentioned purpose, the present invention proposes a battery cell for use in a steel-shell battery. A through hole is provided on the outer shell of the steel-shell battery. The electrode comprises:

[0006] Pole piece;

[0007] The tab comprises a tab body and tab glue, the tab body comprises a first section, a third section and a second section, one end of the first section is arranged on the electrode piece, when the tab passes through the through hole, the first section is located inside the shell, the third section is located outside the shell, and the second section is located inside the through hole; the tab glue is arranged around the tab, and the tab glue is used to seal the through hole.

[0008] In some embodiments, the tab glue includes a first insulating layer, a second insulating layer and a third insulating layer, the first insulating layer is located in the first section, the third insulating layer is located in the third section, and the second insulating layer at least covers the second section; the melting point of the second insulating layer is higher than the melting point of the first insulating layer and the melting point of the third insulating layer.

[0009] In some embodiments, the pole piece further includes adhesive tape, which covers at least a portion of the tab body from one end of the first insulating layer close to the pole piece to one end of the pole piece close to the first insulating layer, so as to insulate the first section from the outer shell.

[0010] In some embodiments, the thickness h of the tab glue ranges from 0.11 mm to 10 mm.

[0011] In some embodiments, a vertical distance w between the side surface of the tab glue and the side surface of the tab is in a range of 2.0 mm to 5.0 mm.

[0012] In some embodiments, the width L of the tab glue ranges from 2.0 mm to 6.0 mm.

[0013] In some embodiments, the melting point of the first insulating layer is T1, the melting point of the second insulating layer is T2, and the melting point of the third insulating layer is T3. The relationship between T1 and T3 satisfies: T1<T3.

[0014] In some embodiments, the relationship between T2 and T3 satisfies: T3<130°C≤T2.

[0015] The present invention further proposes a steel shell battery, comprising a shell and the battery cell described in the aforementioned embodiment, wherein the battery cell is arranged in the shell, a through hole is provided on the shell, the tab is passed through the through hole, and the tab glue seals the through hole.

[0016] In some embodiments, a fourth insulating layer is provided on the outer surface of the housing to insulate the third section from the housing.

[0017] The utility model arranges tab glue around the tab. When the tab directly passes through the through hole on the outer shell of the steel shell battery, the tab glue is used to seal the through hole, which can not only complete the battery packaging, but also the part of the tab located on the outer surface of the outer shell can be directly connected to the electrical equipment. There is no need to weld additional structures such as poles or connecting plates, thereby avoiding the risk of short circuit caused by welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of an embodiment of a pole piece of the present utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the pole ear in the pole piece of the utility model;

[0020] Figure 3 for Figure 2 AA cross-sectional view of the middle tab;

[0021] Figure 4 for Figure 2 Top view of the middle tab;

[0022] Figure 5 This is a partial structural diagram of the steel shell battery of the utility model.

[0023] Reference numerals:

[0024] 100, pole piece; 200, pole ear; 210, first section; 220, second section; 230, third section; 240, pole ear glue; 241, first insulating layer; 242, second insulating layer; 243, third insulating layer; 300, outer shell; 310, through hole; 400, adhesive tape. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the schemes in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0028] In addition, the terms "first," "second," and so on, used in this utility model are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include at least one of such features. Furthermore, the technical solutions of various embodiments may be combined with each other, but this must be based on the ability of a person of ordinary skill in the art to implement them. If the combination of technical solutions contradicts or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0029] The utility model proposes a battery cell, which is applied to a steel shell battery. A through hole is opened on the shell of the steel shell battery. Figure 1-Figure 5 , the battery cell includes:

[0030] Pole piece 100;

[0031] The tab 200 includes a tab body and tab glue 240. The tab body includes a first section 210, a second section 220, and a third section 230. One end of the first section 210 is disposed on the electrode 100, and the other end of the first section 210 is connected to the third section 230. The end of the third section 230 away from the first section 210 is connected to the second section 220.

[0032] The first section 210 is used to be arranged inside the shell 300, the second section 220 is used to be arranged outside the shell, and the third section 230 is used to be arranged in the through hole 310; a tab glue 240 is arranged around the tab 200, and the tab glue 240 is used to seal the through hole 310.

[0033] The electrode sheet 100 typically includes a current collector and an active material layer. The current collector is made of a highly conductive material, such as copper or aluminum foil, and serves as a carrier for the positive and negative electrode materials. It is primarily used to conduct current within the battery, ensuring efficient current transmission during the battery's charge and discharge processes. The current collector is typically coated with an active material layer, which can be applied to only one side of the current collector or to both sides. When the battery is operating, the active material layer undergoes a chemical reaction, generating current that is conducted through the current collector.

[0034] The tab 200 serves as a bridge between the electrode 100 and the external circuit and can be connected to the electrode 100 by welding, bonding, or mechanical fixing. The tab 200 is mainly used to draw current, connect the electrode 100 to the external circuit, and form a complete circuit between the external circuit and the electrode 100 to ensure the normal operation of the battery. Therefore, the tab 200 and the outer shell 300 of the steel shell battery need to be insulated. Therefore, in this embodiment, a tab glue 240 is provided around the tab 200. That is, after the tab 200 passes through the through hole 310 of the outer shell 300, the tab glue 240 separates the pole piece and the outer shell 300, thereby achieving insulation between the two.

[0035] Specifically, a tab glue 240 is provided on the tab 200, and then the tab 200 and the tab glue 240 are controlled to pass through the through hole 310 of the shell 300, so that part of the tab glue 240 is inside the shell 300 and part of the tab glue 240 is outside the shell 300. At this time, the tab 200 can be tightly combined with the through hole 310 by the viscosity and elasticity of the tab glue 240 itself or by applying an adhesive on the through hole 310, thereby achieving the sealing of the through hole 310 and the insulation between the tab 200 and the shell 300. Exemplarily, the tab glue 240 can be set to a tapered shape so that when the tab glue 240 passes through the through hole 310, its size gradually increases, so that the tab 200 can easily pass through the through hole 310 and achieve a sealing effect on the through hole 310 by squeezing. It is understandable that the tab 200 may be passed through the through hole 310 first, and then the tab glue 240 may be applied between the tab 200 and the through hole 310 . The present invention does not limit this.

[0036] The utility model arranges a tab glue 240 around the tab 200. When the tab 200 directly passes through the through hole 310 on the outer shell 300 of the steel shell battery, the tab glue 240 is used to seal the through hole 310, which can not only complete the battery packaging, but also the part of the tab 200 located on the outer surface of the outer shell 300 can be directly connected to the electrical equipment, without the need to weld additional structures such as poles or connecting plates, thereby avoiding the risk of short circuit caused by welding.

[0037] like Figure 2 and Figure 3 As shown, in some embodiments, the ear glue 240 includes a first insulating layer 241, a second insulating layer 242 and a third insulating layer 243, the first insulating layer 241 is located in the first section 210, the second insulating layer 242 at least covers the second section 220, and the third insulating layer 243 is located in the third section 230; the melting point of the second insulating layer 242 is higher than the melting point of the first insulating layer 241, and the melting point of the second insulating layer 242 is higher than the melting point of the third insulating layer 243.

[0038] The tab glue 240 is set as a combination of multiple layers of insulating materials. Due to the different melting points of different materials, the tab glue 240 can be melted in sections, thereby forming a tighter and more reliable sealing structure. The first insulating layer 241 and the third insulating layer 243 are respectively located inside and outside the shell 300, and have a low melting point. They can melt quickly when heated, thereby completing the sealing of the through hole 310 and preventing electrolyte leakage and external contaminants from entering. The second insulating layer 242 melts at a slower speed or does not melt, so that the tab 200 and the shell 300 can be better insulated. Furthermore, a foaming material can be added to the second insulating layer 242 to facilitate the expansion of the second insulating wire when heated, thereby improving the sealing.

[0039] like Figure 1As shown, in some embodiments, the electrode piece also includes adhesive tape 400, which at least covers the portion of the electrode body from one end of the first insulating layer 241 close to the electrode piece 100 to the end of the electrode piece 100 close to the first insulating layer 241, so as to insulate the first section 210 from the shell 300.

[0040] The adhesive tape 400 is made of an insulating material with good chemical stability, such as polyimide adhesive tape 400, which is resistant to high temperatures, chemical corrosion, and has excellent electrical insulation properties. By wrapping the adhesive tape 400 around the portion of the electrode located within the outer shell 300, reliable insulation between the electrode and the outer shell 300 of the steel-shell battery is further ensured, thereby improving the safety and stability of the steel-shell battery. Furthermore, one end of the adhesive tape 400 is bonded to the electrode 100, and the other end of the adhesive tape 400 is bonded to the first insulating layer 241, so that the connection between the adhesive tape 400 and the tab 200 is tighter, while ensuring that the adhesive tape 400 completely protects the portion of the tab 200 located within the outer shell 300, thereby improving the insulation performance.

[0041] like Figure 4 As shown, in some embodiments, the thickness h of the tab glue 240 ranges from 0.11 mm to 10 mm.

[0042] If the thickness h of the tab glue 240 is less than 0.11 mm, the tab glue 240 may not be able to completely fill the gap between the tab 200 and the through-hole 310 when heated and melted, resulting in a loose seal and a high risk of electrolyte leakage, affecting the safety performance and life of the steel-shell battery. In addition, the mechanical strength of the tab glue 240 that is too thin is low and it is easily affected by external shock and vibration, resulting in damage to the tab 200 or sealing failure. If the thickness h of the tab glue 240 is greater than 10 mm, it not only increases the amount of material used, resulting in increased production costs, but also requires a longer melting and curing time due to the thicker glue layer, reducing production efficiency. In addition, the thicker glue layer will hinder the rapid dissipation of heat inside the steel-shell battery, causing the internal temperature of the battery to rise, affecting performance and safety. Therefore, in this embodiment, the thickness h of the tab glue 240 is set to a range of 0.11 mm-10 mm, which can not only achieve sealing of the through-hole 310 but also ensure good mechanical properties.

[0043] like Figure 2 As shown, in some embodiments, the vertical distance w between the side surface of the tab glue 240 and the side surface of the tab 200 ranges from 2.0 mm to 5.0 mm.

[0044] If w is less than 2 mm, the tab glue 240 is too little, which may result in the inability to completely fill the gap between the tab 200 and the through hole 310, affecting the safety performance of the steel-cased battery; if w is greater than 5 mm, it will lead to increased production costs, and correspondingly, the through hole 310 of the outer shell 300 will also be larger, increasing the processing difficulty and not conducive to sealing the through hole 310. Therefore, in this embodiment, w is set to 2.0 mm-5.0 mm, which can not only ensure the sealing performance of the tab glue 240, but also facilitate installation and save costs.

[0045] like Figure 2 As shown, in some embodiments, the width L of the tab glue 240 ranges from 2.0 mm to 6.0 mm. If the width of the tab glue 240 is less than 2 mm, the tab glue 240 uses too little material, and it is easy to be affected by errors and the like during the actual production process, resulting in the inability to seal the through hole 310; if the width of the tab glue 240 is greater than 6 mm, the tab glue 240 uses too much material, resulting in increased costs. Therefore, in this embodiment, the width of the tab glue 240 is set to 2.0 mm to 6.0 mm, for example, the width of the tab glue 240 is 4 mm, which can ensure the sealing performance of the tab glue 240 and reduce the production cost. Furthermore, the width of the first insulating layer 241 is controlled to be greater than 2 mm, so that the adhesive tape 400 is adhered to the first insulating layer 241 during the subsequent production process to achieve insulation of the tab 200 inside the housing 300.

[0046] In some embodiments, the melting point of the first insulating layer 241 is T1, the melting point of the second insulating layer 242 is T2, and the melting point of the third insulating layer 243 is T3. The relationship among T1, T2, and T3 satisfies: T1 < T3. Because the heat source is outside the steel-cased battery when the tab glue 240 is heated to melt, the temperature inside the steel-cased battery is lower than the temperature outside the steel-cased battery, causing the melting point of the first insulating layer 241 to be lower than the melting point of the second insulating layer 242.

[0047] In some embodiments, the relationship between T2 and T3 satisfies: T3<130°C≤T2.

[0048] The pore structure of the diaphragm changes at high temperatures, causing the pores to shrink or close, thereby preventing the electrolyte from passing through and the migration of lithium ions between the positive and negative electrodes. The closed-pore temperature of a typical diaphragm is below 135°C. Therefore, the melting points of the first insulating layer 241 and the third insulating layer 243 are controlled to be below 130°C, allowing them to melt at a lower temperature, thereby sealing the through-hole 310 and avoiding damage to the diaphragm. The higher temperature of the second insulating layer 242 prevents the second insulating layer 242 from melting too quickly, causing the outer shell 300 to come into contact with the tab 200, affecting the insulation performance of the steel-shell battery.

[0049] The present invention further proposes a steel shell battery, comprising a shell 300 and a battery cell. The specific structure of the battery cell refers to the above embodiment. Since the battery cell adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be described in detail here. Figure 5 (Part of the housing 300 is not shown), wherein the battery cell is arranged in the housing 300, a through hole 310 is provided on the housing 300, the tab 200 is passed through the through hole 310, and the tab glue 240 blocks the through hole 310. The shape of the through hole 310 is usually similar to that of the tab 200 or the tab glue 240. For example, if the tab 200 is flat, the through hole 310 is also set to be flat to prevent the through hole 310 from being too large and increasing the difficulty of sealing.

[0050] In some embodiments, a fourth insulating layer is provided on the outer surface of the outer shell 300 to insulate the third section 230 from the outer shell 300. By applying the insulating layer on the outer surface of the outer shell 300, the third section 230 of the tab 200 is prevented from contacting the outer surface of the outer shell 300 and causing a short circuit, thereby improving the safety performance of the steel-cased battery.

[0051] The above description is only part or preferred embodiments of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. A battery cell, used in a steel-shell battery, wherein a through hole is provided on the outer shell of the steel-shell battery, characterized in that: The battery cell comprises: Pole piece; The tab includes a tab body and tab glue, the tab body includes a first section, a second section and a third section, one end of the first section is disposed on the electrode sheet, the other end of the first section is connected to the second section, and the end of the second section away from the first section is connected to the third section; The first section is used to be arranged inside the shell, the third section is used to be arranged outside the shell, and the second section is used to be arranged in the through hole; a tab glue is arranged around the tab, and the tab glue is used to seal the through hole.

2. The battery cell according to claim 1, characterized in that The tab glue includes a first insulating layer, a second insulating layer and a third insulating layer, the first insulating layer is located in the first section, the second insulating layer at least covers the second section, and the third insulating layer is located in the third section; the melting point of the second insulating layer is higher than the melting point of the first insulating layer, and the melting point of the second insulating layer is higher than the melting point of the third insulating layer.

3. The battery cell according to claim 2, characterized in that The pole piece further includes adhesive tape, which covers at least a portion of the tab body from one end of the first insulating layer close to the pole piece to one end of the pole piece close to the first insulating layer, so as to insulate the first section from the shell.

4. The battery cell according to claim 1, characterized in that The thickness h of the tab glue ranges from 0.11 mm to 10 mm.

5. The battery cell according to claim 1, characterized in that The vertical distance w between the side surface of the tab glue and the side surface of the tab is in the range of 2.0 mm to 5.0 mm.

6. The battery cell according to claim 1, characterized in that The width L of the tab glue is in the range of 2.0 mm to 6.0 mm.

7. The battery cell according to claim 2, characterized in that The melting point of the first insulating layer is T1, the melting point of the second insulating layer is T2, and the melting point of the third insulating layer is T3. The relationship between T1 and T3 satisfies: T1<T3.

8. The battery cell according to claim 7, characterized in that: The relationship between T2 and T3 satisfies: T3<130℃≤T2.

9. A steel shell battery, characterized in that: The invention comprises a shell and the battery cell according to any one of claims 1 to 8, wherein the battery cell is arranged in the shell, the shell is provided with a through hole, the tab is passed through the through hole, and the tab glue seals the through hole.

10. The steel shell battery according to claim 9, characterized in that: The outer surface of the shell is provided with a fourth insulating layer for insulating the third section from the shell.

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