Battery and battery pack

Abstract

The utility model relates to the field and discloses a battery and a battery pack. The utility model provides a battery which comprises a shell, a top cover and a battery cell, the shell is provided with an opening, the top cover covers the opening of the shell and forms an accommodating cavity with the shell, and the battery cell is arranged in the accommodating cavity; a first insulating coating is arranged on the outer surface of the shell; a second insulating coating is arranged on the surface, deviating from the battery cell, of the top cover, and the ratio of the thickness d2 of the second insulating coating to the thickness d1 of the first insulating coating is 0.5-0.95, so that the insulation reliability and the heat dissipation performance of the battery are improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a battery and a battery pack. Background Art

[0002] Existing commercial batteries usually include a shell and a top cover. The top cover is provided with components such as poles. During the operation of the battery, the poles, as current conductors, will generate a lot of heat. In order to protect the insulation of the cover plate, a thick insulating plate is usually provided on the surface of the cover plate. The insulating plate will affect the heat dissipation of the cover plate, causing heat accumulation, which is not conducive to improving the safety of the battery. Utility Model Content

[0003] The present application discloses a battery and a battery pack for improving the insulation reliability and heat dissipation of the battery.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] In a first aspect, the present application provides a battery, the battery comprising a shell, a top cover and a battery cell, the shell being provided with an opening, the top cover being covered at the opening of the shell and forming a receiving cavity with the shell, the battery cell being arranged in the receiving cavity;

[0006] The outer surface of the shell is provided with a first insulating coating; the surface of the top cover away from the battery core is provided with a second insulating coating, and the ratio of the thickness d2 of the second insulating coating to the thickness d1 of the first insulating coating is 0.5-0.95.

[0007] In the battery of the present application, a first insulating coating is provided on the outer surface of the shell, and the first insulating coating is used to achieve insulation between batteries. A second insulating coating is provided on the surface of the top cover, wherein the thickness of the second insulating coating is less than the thickness of the first insulating coating, which can greatly improve the heat dissipation capacity of the cover.

[0008] In a second aspect, the present application provides a battery pack, which includes a plurality of batteries of the present application, and the plurality of batteries are arranged along a width direction of the battery.

[0009] The battery pack of the present application, because it has the battery of the present application, can have all the advantages of the first aspect of the present application, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0011] Figure 2 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0012] Figure 3 A schematic diagram of the exploded structure of a battery;

[0013] Figure 4 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application.

[0014] Figure Number:

[0015] 01-battery; 10-housing; 11-first insulating coating; 111-first side; 112-second side;

[0016] 20-top cover; 21-pole; 22-pressure relief mechanism; 23-second insulating coating; 30-insulating plate. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] The heat dissipation and insulation of the battery are two major factors affecting the safety of the battery. The present application provides a first insulating coating on the outer surface of the shell to improve the insulation of the battery, and a second insulating coating with a relatively thin thickness is provided on the top cover. While ensuring the insulation of the top cover, the heat dissipation of the top cover surface is enhanced to prevent heat from accumulating at the corners of the battery, thereby improving the insulation and heat dissipation of the battery. The structure of the battery of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0019] Figure 1 Figure 1 is a schematic diagram of the structure of a battery. Figure 1 As shown, the battery includes a shell 10, a battery cell (not shown in the figure) and a top cover 20. One side of the shell 10 is provided with an opening, and the top cover 20 covers the opening to form a receiving cavity. The battery cell is arranged in the receiving cavity. The battery cell can be a stacked core or a rolled core. Among them, the stacked core includes a positive electrode sheet, a negative electrode sheet and a diaphragm arranged in layers. The diaphragm is arranged between the positive electrode sheet and the negative electrode sheet. The rolled core is formed by winding the positive electrode sheet, the diaphragm and the negative electrode sheet.

[0020] like Figure 1 As shown, the housing 10 is a rectangular parallelepiped structure. The length direction of the top cover 20 is the length direction of the housing 10. Figure 1 The width direction of the top cover 20 is the width direction of the housing 10, as shown in Figure 1 The thickness direction of the top cover 20 is the height direction of the housing 10, as shown in Figure 1 The z direction is shown in .

[0021] The shell of the battery is a metal shell, for example, a stainless steel shell, an aluminum alloy shell, a carbon steel shell, etc. In the embodiment of the present application, the shell of the battery is an aluminum alloy shell. In order to avoid short circuits between batteries, a first insulating coating 11 is provided on the outer surface of the shell. The outer surface of the shell is the surface facing away from the battery cell, and the inner surface of the shell is the surface facing the battery cell. The first insulating coating 11 can be formed by spraying, coating, brushing or electrophoresis. After spraying, coating or brushing the slurry, the slurry can be cured by light or heating to form a first insulating coating. The first insulating coating 11 may, for example, include a resin material. As an exemplary illustration, the first insulating coating 11 may, for example, be a polyethylene coating, a polyurethane coating, an epoxy resin coating, a potassium silicate coating, a siloxane coating, etc.

[0022] The top cover of the battery can be a metal top cover, for example, an aluminum alloy top cover, a stainless steel top cover or a carbon steel top cover. In the embodiment of the present application, the top cover is an aluminum alloy top cover. Figure 1 , the top cover 20 may include a top cover body, on which a pole 21 and other structures may be provided, and a pressure relief mechanism 22 and a liquid injection hole (not shown in the figure) may also be provided. Since the top cover 20 needs to be insulated from other components, a second insulating coating 23 is provided on the surface of the top cover 20. The thickness d2 of the second insulating coating 23 may be less than the thickness d1 of the first insulating coating 13, and the range of d2 / d1 is 0.5-0.95. Exemplarily, the ratio of d2 / d1 may be, for example, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, or 0.95 or any value between the above two values. The first insulating coating 13 can achieve insulation between batteries and between the battery housing and external connection components. The second insulating coating 23 can ensure the insulation of the top cover. At the same time, the thickness of the second insulating coating 23 is relatively low, and its thickness d2 can be 40-200μm to enhance the heat dissipation capacity of the cover plate. Exemplarily, the thickness of d2 may be 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm or any value between the above two values.

[0023] Figure 2 This is a schematic diagram of the structure of a battery in another embodiment of the present application. Figure 2As shown, in one embodiment, the second insulating coating 23 can be arranged along the circumferential edge of the top cover 20, and the width of the second insulating coating 23 extending from the edge of the top cover 20 to the middle area of ​​the top cover 20 is 1-20mm. Exemplarily, the width of the second insulating coating can be, for example, 1μm, 20μm, 30μm, 40μm, 50μm, 60μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, or 20μm or any value between the above two values. This setting structure facilitates the spraying of the first insulating coating and the second insulating coating. In another embodiment, the first insulating coating extends to the edge of the top cover or covers part of the second insulating coating. On the surface of the top cover, the second insulating coating can form a concave structure, and its thickness is slightly thicker along the four sides of the top cover, and its thickness is slightly thinner in the middle part.

[0024] The first insulating coating and the second insulating coating of the above structure can form the first insulating coating on the surface of the shell and the second insulating coating on the edge surface of the top cover by adjusting the relative inclination angle of the spray gun and the shell during the spraying process, thereby improving the spraying efficiency. Due to the presence of a transition portion between the top cover and the shell, it is easy to form a pile of materials in the transition portion during spraying, resulting in a thicker thickness of the first insulating coating in the transition portion, thereby increasing the insulation safety between batteries. In addition, if the first insulating coating and the second insulating coating are formed by spraying twice or multiple times, multiple spraying can be performed on the transition portion during spraying to increase the thickness of the first insulating coating at the transition portion and increase the insulation of the battery.

[0025] In one embodiment, the second insulating coating covers the non-functional area of ​​the top cover to improve the insulation of the top cover. The functional area of ​​the top cover includes the area where the pole, the pressure relief mechanism, the injection hole and the QR code sticker area are set. The non-functional area of ​​the top cover is the area excluding the pole, the pressure relief mechanism, the injection hole and the QR code sticker area of ​​the top cover.

[0026] In one embodiment, the battery is provided with a pressure relief mechanism, the pressure relief mechanism is provided on the top cover, and the spacing between the second insulating coating and the pressure relief mechanism meets 2-300mm. Exemplarily, the spacing between the second insulating coating and the pressure relief mechanism can be, for example, 2mm, 5mm, 10mm, 15mm, 20mm, 30mm, 40mm, 50mm, 70mm, 80mm, 100mm, 120mm, 140mm, 160mm, 180mm, 200mm, 220mm, 240mm, 260mm, 280mm or 300mm or any value between the above two values. When the pressure relief mechanism is provided with a top cover, at the pressure relief mechanism, a certain spacing must be maintained between the second insulating coating and the pressure relief mechanism to prevent the second insulating coating from adhering to the surface of the pressure relief mechanism during the spraying process and blocking the pressure relief mechanism. At the same time, it can avoid the pressure relief mechanism from exploding in time when the subsequent battery undergoes thermal runaway. At the same time, when the battery temperature is too high, the second insulating coating may melt. If the second insulating coating is in close contact with the pressure relief mechanism, the second insulating coating may block the pressure relief mechanism after melting. Therefore, maintaining the above range between the second insulating coating and the pressure relief mechanism can help improve the safety of the battery.

[0027] Figure 3 FIG. 1 is a schematic diagram of a battery structure of an embodiment. Figure 3 As shown, in one embodiment, an insulating plate 30 is provided on one side of the top cover 20 where the second insulating coating is provided, and the length of the insulating plate 30 is the same as the length of the top cover 20. The product of the thickness d2 of the second insulating coating and the thickness m of the insulating plate satisfies 1000-60000, that is, d2*m is less than or equal to 60000, and greater than or equal to 1000. The thickness unit of the coating thickness is μm; the thickness unit of the insulating plate is μm. Illustratively, the value of d2*m may be 1000, 2000, 5000, 8000, 10000, 12000, 15000, 18000, 20000, 22000, 25000, 28000, 30000, 32000, 35000, 38000, 40000, 45000, 50000, 55000, 60000 or a value between any two of the above values.

[0028] An insulating plate is provided on the surface of the top cover to increase the overall insulation performance of the battery. However, when providing the insulating plate, in order to prevent the overall height of the battery from being too high and occupying the box space, the thickness of the insulating plate can be made thinner than that of the traditional insulating plate. When the thickness of the second insulating coating is small, the thickness of the insulating plate can be set relatively thick. When the thickness of the second insulating coating is thick, the thickness of the insulating plate can be set relatively thin. When the thickness of the second insulating coating and the thickness of the insulating plate satisfy d2*m less than or equal to 60000 and greater than or equal to 1000., it can be avoided that both are too thick at the same time, so that the top cover meets the heat dissipation requirements.

[0029] In one embodiment, the battery is provided with a pressure relief mechanism, and the pressure relief mechanism is arranged on the bottom surface of the shell opposite to the top cover. Wherein, when the pressure relief mechanism is arranged on the bottom surface of the shell, an exposed area can be arranged on the bottom surface, and the pressure relief mechanism is arranged in the exposed area. In this arrangement structure, the thickness of the second insulating coating is 60-200μm. An exposed area is arranged on the bottom surface of the shell to arrange the pressure relief mechanism in the exposed area, which is convenient for the pressure relief mechanism to explode when the battery has thermal runaway. In addition, the exposed area can increase the connection between the battery and other structures, such as strengthening the bonding strength between the shell and the box of the battery pack. The pressure relief mechanism is arranged on the bottom surface of the shell, and there is no need to shield the pressure relief mechanism during spraying, which can reduce the difficulty of spraying. At the same time, when spraying, the paint can also be prevented from falling on the position of the pressure relief mechanism. In addition, the pressure relief mechanism is arranged on the bottom surface, which can also prevent the heat from causing the second insulating coating on the surface of the cover plate to melt when the battery has thermal runaway. In addition, the heat is concentrated to the position of the pressure relief mechanism, and the thickness of the second coating can be set larger to increase the insulation performance of the cover surface.

[0030] In one embodiment, the battery cell includes a positive electrode sheet, a separator and a negative electrode sheet, and at least one of the positive electrode sheet and the negative electrode sheet includes a current collector. The current collector in the positive electrode sheet is a positive electrode current collector, and the current collector in the negative electrode sheet is a negative electrode current collector. In addition to the current collector, the positive electrode sheet and the negative electrode sheet may also include an active layer. The composition of the active layer of the positive electrode sheet and the negative electrode sheet is different. The current collector includes a conductive layer and a polymer layer, and the ratio of the thickness of the polymer layer to the thickness of the current collector is 0.1-0.9, and the thickness of the second insulating coating is 40-140μm. Exemplarily, the ratio of the thickness of the polymer layer to the thickness of the current collector may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or a value between any two of the above values.

[0031] In the current collector, the thicker the polymer layer is, the thinner the conductive layer is, the smaller the flow area is, and the heat generation increases. At this time, the thickness of the second insulating coating needs to be set relatively small to keep the top cover at a high heat dissipation performance.

[0032] The material of the polymer layer can be selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyetheretherketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylenenaphthalene, polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, polyvinylidene fluoride-hexafluoropropylene, poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyethernitrile, polyurethane, polyphenylene oxide, polyester and polysulfone and their derivatives. The material of the conductive layer can be selected from at least one of Ni, Ti, Cu, Ag, Au, Pt, Fe, Co, Cr, W, Mo, Al, Mg, K, Na, Ca, Sr, Ba, Si, Ge, Sb, Pb, In, Zn and their combinations (alloys).

[0033] Based on the same technical purpose, an embodiment of the present application also provides a battery pack. Figure 4 Figure 1 is a schematic diagram of the structure of a battery pack. Figure 4 As shown, the battery pack includes multiple batteries 01 of the present application, and in addition, may also include a bus bar (not shown in the figure). The multiple batteries are arranged along the width direction of the battery, such as along the y direction shown in the figure. The bus bar connects the poles of different batteries to achieve series and parallel connection between multiple batteries. In this embodiment, the battery includes four side surfaces, and the two side surfaces are arranged opposite to each other. Figure 3 The areas of the two first side surfaces 111 are greater than the areas of the two second side surfaces 112, and the first side surface 111 is a large surface of the battery. The arrangement direction of the multiple batteries is perpendicular to the large surface of the battery.

[0034] Based on the same technical purpose, the embodiment of the present application provides an electric device, which includes the battery of the present application or the battery pack of the present application. The electric device of the embodiment of the present application includes but is not limited to electric vehicles, new energy charging stations, energy storage systems and other equipment.

[0035] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A battery, characterized in that: include: A shell, a battery cell and a top cover, wherein the shell is provided with an opening, the top cover is covered at the opening of the shell and forms a receiving cavity with the shell, and the battery cell is arranged in the receiving cavity; The outer surface of the shell is provided with a first insulating coating; the surface of the top cover facing away from the battery core is provided with a second insulating coating, and the ratio of the thickness d2 of the second insulating coating to the thickness d1 of the first insulating coating is 0.5-0.

95.

2. The battery according to claim 1, characterized in that The thickness d2 of the second insulating coating layer is 40-200 μm.

3. The battery according to claim 1, characterized in that The second insulating coating is arranged along the circumferential edge of the top cover, and the width of the second insulating coating extending from the edge of the top cover to the middle area of ​​the top cover is 1-20 mm.

4. The battery according to any one of claims 1 to 3, characterized in that: The first insulating coating layer extends to an edge of the top cover or covers a portion of the second insulating coating layer.

5. The battery according to any one of claims 1 to 3, characterized in that: The battery is provided with a pressure relief mechanism, which is arranged on the top cover, and the distance between the second insulating coating and the pressure relief mechanism meets the range of 2-300 mm.

6. The battery according to any one of claims 1 to 3, characterized in that: An insulating plate is provided on one side of the top cover where the second insulating coating is provided, and the length of the insulating plate is the same as that of the top cover.

7. The battery according to claim 6, characterized in that The thickness d2 of the second insulating coating layer and the thickness m of the insulating plate satisfy: d2*m is 1000-60000; the thickness unit of the coating layer is μm; the thickness unit of the insulating plate is μm.

8. The battery according to any one of claims 1 to 3, characterized in that: The battery is provided with a pressure relief mechanism, and the pressure relief mechanism is arranged on the bottom surface of the shell body opposite to the top cover; The bottom surface is provided with an exposed area, and the pressure relief mechanism is arranged in the exposed area; The thickness of the second insulating coating layer is 60-200 μm.

9. The battery according to any one of claims 1 to 3, characterized in that: The battery cell includes a positive electrode sheet, a separator and a negative electrode sheet. At least one of the positive electrode sheet and the negative electrode sheet includes a current collector. The current collector includes a conductive layer and a polymer layer. The ratio of the thickness of the polymer layer to the thickness of the current collector is 0.1-0.

9. The thickness of the second insulating coating is 40-140 μm.

10. A battery pack, characterized in that: The invention comprises a plurality of batteries as claimed in any one of claims 1 to 9, wherein the plurality of batteries are arranged along the width direction of the battery.

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