Battery monomer, battery pack and power device

Abstract

The utility model discloses a battery monomer, a battery pack and a power device, the battery monomer comprises a shell, a battery pack and a battery pack, the shell is internally provided with an accommodating cavity; the pole group is arranged in the containing cavity, the pole group comprises a pole piece and a clamping piece, the pole piece comprises a first piece, a second piece and a third piece which are connected in sequence, the first piece and the third piece are arranged in a stacked mode, the second piece is bent, and the clamping piece is arranged between the first piece and the third piece; the pole group is provided with a containing cavity, the exhaust pin is arranged in the containing cavity, the pole group is provided with an avoiding part, and the exhaust pin is arranged at the position of the avoiding part. According to the single battery disclosed by the utility model, by arranging the laminated and bent pole piece of the pole group, the bending area of the pole piece is reduced, the production process of the pole group is simplified, the production efficiency of the pole group is improved, the energy density of the pole group is also improved, and the randomness of the exhaust direction when the single battery is subjected to thermal runaway is avoided by arranging the exhaust pin.

Description

Technical Field

[0001] The utility model relates to the technical field of battery manufacturing, in particular to a battery cell, a battery pack and a power device. Background Art

[0002] It is pointed out in the related art that as a new type of secondary battery, the lithium-ion battery has the advantages of high energy density, high working voltage and long cycle life. With the continuous improvement of social demands, not only various performance parameters of the lithium-ion battery are emphasized, but also higher requirements are put forward for the safety of the lithium-ion battery. How to improve the safety performance of the battery on the premise of ensuring the basic performance of the lithium-ion battery has become an important part of the subsequent battery research.

[0003] At present, according to the grouping form of the lithium-ion electrode group, the lithium-ion electrode group can be divided into a stacked type and a wound type. Generally speaking, the wound electrode group has a simple process and high production efficiency. When thermal runaway occurs, the exhaust direction is fixed, which promotes the gas to be discharged from the battery interior faster. However, due to the limitation of the electrode sheet, the wound electrode group usually has a low energy density and a short cycle life. The stacked electrode group requires multiple cuttings and stackings of the electrode sheets, resulting in low production efficiency. At the same time, due to the high uniformity of the electrode sheets, the randomness of the thermal runaway exhaust direction causes a more serious impact on the housing. On the contrary, the high uniformity of the stacked electrode group brings the advantages of high energy density and long cycle life. Summary of the Utility Model

[0004] The utility model aims to at least solve one of the technical problems existing in the prior art. For this reason, the utility model provides a battery cell, and the battery cell has a high energy density and a long cycle life.

[0005] The utility model also provides a battery pack having the above battery cell.

[0006] The utility model also provides a power device having the above battery pack.

[0007] The battery cell according to the first aspect of the utility model includes: a housing, an accommodation cavity is formed in the housing; an electrode group, the electrode group is arranged in the accommodation cavity, the electrode group includes electrode sheets and clip sheets, the electrode sheets include a first sheet, a second sheet and a third sheet which are connected in sequence, the first sheet and the third sheet are stacked, and the second sheet is bent, and the clip sheets are arranged between the first sheet and the third sheet; an exhaust pin, the exhaust pin is arranged in the accommodation cavity, an avoidance part is formed in the electrode group, and the exhaust pin is arranged at the position of the avoidance part.

[0008] According to the battery cell of the present utility model, by arranging the laminated and bent pole pieces of the pole group, the bending area of the pole pieces is reduced, the production process of the pole group is simplified, the production efficiency of the pole group is improved, the energy density of the pole group is increased, the cycle life is prolonged, the consistency of the pole pieces is improved, and the exhaust pin is arranged to avoid the randomness of the exhaust direction when the battery cell undergoes thermal runaway, reduce the impact on the housing, and improve the overall safety of the battery cell.

[0009] In some embodiments, pole tabs are respectively arranged at both ends of the first sheet and both ends of the second sheet. The pole piece is coated with a first coating and a second coating. The first coating is formed between the second coating and the pole piece. Both the first sheet and the third sheet are coated with the first coating and the second coating. At least one of the first coating and the second coating is coated on the second sheet. Both the first coating and the second coating include conductive materials. The content of the conductive material in the second coating is 0.5%-1% higher than that in the first coating.

[0010] In some embodiments, the width w of the second sheet, the full length r of the pole piece, and the pole group thickness h satisfy: w = πr + (h - 2r).

[0011] In some embodiments, the pole piece includes a positive pole piece and a negative pole piece. A separator is coated on the negative pole piece. The edge of the separator extends at least 1 mm beyond the edge of the negative pole piece. The separator includes a base film, a protective layer, and an adhesive layer. The base film is made of polypropylene material, the protective layer is made of alumina ceramic material, and the adhesive layer is made of polyvinylidene fluoride hexafluoropropylene material.

[0012] In some embodiments, the exhaust pin includes: a main body bracket, the main body bracket includes a first plate, a second plate, and two third plates. The two third plates are respectively arranged on both sides of the first plate and are symmetrically arranged. The first plate includes a first section and a second section. The first section extends along a first direction, and the second section extends along a second direction perpendicular to the first direction. The second plate extends along the second direction. Each of the third plates is formed with a chute, and the chutes are arranged oppositely; a baffle, the baffle is arranged between the two third plates and is spaced from the first plate. One end of the second plate is connected to one end of the baffle. The baffle and the main body bracket define an air flow channel. The other end of the baffle extends in a direction away from the second section in the first direction. In the direction towards the second section, the cross-sectional area of the air flow channel gradually increases, and the thickness of the baffle is not greater than the width of the chute.

[0013] In some embodiments, on the side of the baffle away from the air flow channel, the baffle and the third plate define a groove, the width of the groove is not less than the thickness of the electrode group, and / or, the first plate is made of polypropylene and integrally injection molded.

[0014] In some embodiments, the battery cell further includes: an explosion-proof valve and a cover plate. The cover plate is disposed at both ends of the housing and an explosion-proof opening is formed on the cover plate. The explosion-proof valve is disposed at the position of the explosion-proof opening. The explosion-proof valve includes: a support member, the support member includes two arc-shaped plates protruding in opposite directions, and the support member is connected to the cover plate; a connecting member; a plugging prevention member. The connecting member is connected between the support member and the plugging prevention member. One side surface of the plugging prevention member away from the connecting member protrudes in a direction away from the connecting member. The projected area of the plugging prevention member on the cover plate is larger than the area of the explosion-proof opening; a packaging film, and the packaging film seals the explosion-proof opening.

[0015] The battery pack according to the second aspect of the present invention includes at least one battery cell according to the first aspect of the present invention above.

[0016] According to the battery pack of the present invention, by providing the battery cell of the first aspect above, the overall performance and energy density of the battery pack are improved, the cycle life is extended, and the safety of the battery pack is enhanced.

[0017] The power device according to the third aspect of the present invention includes the battery pack according to the second aspect of the present invention above.

[0018] According to the power device of the present invention, by providing the battery pack of the second aspect above, the overall performance and energy density of the power device are improved, the safety of the power device is enhanced, and the operation strength and duration of the power device are ensured.

[0019] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0020] Figure 1 is a schematic diagram of a battery cell according to an embodiment of the present invention;

[0021] Figure 2 is Figure 1 a schematic diagram of the electrode group shown in

[0022] Figure 3 is Figure 2 a schematic diagram of a side view of the electrode group shown in

[0023] Figure 4 is Figure 2Schematic diagram of the assembly of the electrode group shown in;

[0024] Figure 5 is Figure 4 Side view of the assembled electrode group shown in;

[0025] Figure 6 is Figure 1 Schematic diagram of the exhaust pin shown in;

[0026] Figure 7 is Figure 6 Schematic diagram of the bottom view of the exhaust pin shown in;

[0027] Figure 8 is Figure 6 Schematic diagram of the side view of the exhaust pin shown in;

[0028] Figure 9 is Figure 1 Schematic diagram of the explosion-proof valve shown in;

[0029] Figure 10 is Figure 9 Schematic diagram of the top view of the explosion-proof valve shown in;

[0030] Reference numerals:

[0031] 100, battery cell;

[0032] 1, housing;

[0033] 2, electrode group;

[0034] 21, electrode plate; 211, first plate; 212, second plate; 213, third plate; 214, separator;

[0035] 22, clip; 23, first coating; 24, second coating;

[0036] 25, relief portion; 26, tab;

[0037] 3, exhaust pin; 31, first plate; 32, second plate; 33, third plate;

[0038] 34, baffle; 35, air flow channel; 36, exhaust channel;

[0039] 4, explosion-proof valve; 41, support member; 42, connecting member; 43, anti-blocking member; 44, encapsulation film;

[0040] 5, cover plate; 51, explosion-proof port. Detailed implementation manners

[0041] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present utility model and should not be construed as a limitation to the present utility model.

[0042] Reference will be made below Figures 1 to 10 to describe the battery cell 100 according to an embodiment of the first aspect of the present utility model.

[0043] As Figure 1 shown, the battery cell 100 according to an embodiment of the first aspect of the present utility model includes: a housing 1, an electrode group 2, and an exhaust pin 3.

[0044] Specifically, a receiving cavity is formed in the housing 1, the electrode group 2 is disposed in the receiving cavity, the electrode group 2 includes electrode plates 21 and clamping plates 22, the electrode plates 21 include a first plate 211, a second plate 212, and a third plate 213 connected in sequence, the first plate 211 and the third plate 213 are stacked, the second plate 212 is bent, the clamping plates 22 are disposed between the first plate 211 and the third plate 213, the exhaust pin 3 is disposed in the receiving cavity, and the electrode group 2 forms an avoidance portion 25, and the exhaust pin 3 is disposed at the position of the avoidance portion 25. Thus, the structure of the battery cell 100 is simple, the design is ingenious, and the safety factor is high.

[0045] For the battery cell 100 according to an embodiment of the present utility model, by providing the electrode plates 21 of the electrode group 2 that are stacked and bent, the area of bending of the electrode plates 21 is reduced, the production process of the electrode group 2 is simplified, the production efficiency of the electrode group 2 is improved, the energy density of the electrode group 2 is increased, the cycle life is extended, the consistency of the electrode plates 21 is improved, and the exhaust pin 3 is provided to avoid the randomness of the exhaust direction when the battery cell 100 undergoes thermal runaway, reduce the impact on the housing 1, and improve the overall safety of the battery cell 100.

[0046] In some embodiments of the present utility model, tab ears 26 are respectively provided at both ends of the first sheet 211 and both ends of the second sheet 212. A first coating 23 and a second coating 24 are coated on the electrode sheet 21. The first coating 23 is formed between the second coating 24 and the electrode sheet 21. The first coating 23 and the second coating 24 are both coated on the first sheet 211 and the third sheet 213. At least one of the first coating 23 and the second coating 24 is coated on the second sheet 212. That is to say, the first coating 23 and the second coating 24 are coated on the first sheet 211, the first coating 23 and the second coating 24 are coated on the third sheet 213, and at least the first coating 23 is coated on the second sheet 212. In this way, the thickness of the second sheet 212 is less than the thickness of the first or third sheet 213, or the first coating 23 and the second coating 24 are coated on the second sheet 212, and the thickness of the first coating 23 and the second coating 24 coated on the second sheet 212 is less than the thickness of the first coating 23 and the second coating 24 coated on the first sheet 211 or the third sheet 213.

[0047] For example Figure 2 As shown, the first coating 23 and the second coating 24 are coated on the first sheet 211, the first coating 23 and the second coating 24 are coated on the third sheet 213, and the first coating 23 is coated on the second sheet 212. Thus, by designing that the thickness of the coating coated on the second sheet 212 is less than the thickness of the coating coated on the first sheet 211 or the third sheet 213, the influence on the electrode sheet 21 is minimized when the electrode sheet 21 is bent.

[0048] In some embodiments of the present utility model, both the first coating 23 and the second coating 24 include conductive materials, and the content of the conductive material in the second coating 24 is 0.5%-1% higher than the content of the conductive material in the first coating 23. Thus, the electrical performance advantage of the battery cell 100 is ensured. For example, the content of the conductive material in the second coating 24 is 0.5%-1% higher than the content of the conductive material in the first coating 23, and it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc. Specifically, in order to ensure the electrical performance advantage of the lithium-ion battery, the binder content of the second coating 24 is 3%-5% higher than that of the first coating 23, and the compaction density of the second coating 24 is 1%-2% lower than that of the first coating 23.

[0049] In order to improve the safety characteristics of the electrode sheet 21, different active materials are used to configure the first coating 23 and the second coating 24. Generally speaking, the active material of the first coating 23 is selected as a general active material with low safety, while the second coating 24 is selected as an active material with high safety.

[0050] For the positive electrode plate 21, the active material of the first coating 23 is selected from high-nickel nickel cobalt manganese materials, lithium iron phosphate materials, etc., and the active material of the second coating 24 is selected from low-nickel nickel cobalt manganese materials, lithium manganese iron phosphate materials, and corresponding high-safety materials. Preferably, the active material of the first coating 23 is a high-nickel nickel cobalt manganese material, while the second coating 24 is a low-nickel nickel cobalt manganese material, or a lithium manganese iron phosphate material, or a low-nickel nickel cobalt manganese material coated with alumina, or a lithium manganese iron phosphate material coated with alumina; the active material of the first coating 23 is a lithium iron phosphate material, while the second coating 24 is a lithium manganese iron phosphate material or a lithium iron phosphate material coated with alumina.

[0051] For the negative electrode plate 21, preferably, the active material of the first coating 23 is natural graphite and the second coating 24 is artificial graphite, or natural graphite coated with alumina.

[0052] Moreover, for the positive electrode plate 21, the current collector is selected as aluminum foil, and for the negative electrode plate 21, the current collector is selected as copper foil.

[0053] Furthermore, the width w of the second sheet 212 satisfies the following relationship with the full length r of the electrode plate 21 and the thickness h of the electrode group 2: w = πr + (h - 2r). Thereby, the blind use of inappropriate casings 1 and electrode groups 2 is avoided, the production efficiency of the battery cell 100 is improved, the product quality of the battery cell 100 is enhanced, and the production cost of the battery cell 100 is reduced.

[0054] In some embodiments of the present invention, the electrode plate 21 includes a positive electrode plate 21 and a negative electrode plate 21. A separator 214 is coated on the negative electrode plate 21, and the edge of the separator 214 extends beyond the edge of the negative electrode plate 21 by at least 1 mm. Moreover, when the separator 214 is laminated with the negative electrode plate 21, the hot pressing temperature is in the range of 65°C - 85°C. For example, the hot pressing temperature can be 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, etc. Thereby, it is ensured that the separator 214 can completely wrap the negative electrode plate 21, and the product quality of the battery cell 100 is guaranteed.

[0055] Preferably, the separator 214 includes a base film, a protective layer, and an adhesive layer. The base film is made of polypropylene, the protective layer is made of alumina ceramic, and the adhesive layer is made of polyvinylidene fluoride hexafluoropropylene.

[0056] Specifically, before forming the electrode group 2, the negative electrode plate 21 and the separators 214 arranged on both sides of the negative electrode plate 21 are laminated into an integrated composite sheet through a hot pressing device. During the forming process, the positive electrode plates 21 and the negative electrode plates 21 are stacked in sequence. When all the positive electrode plates 21 and the negative electrode plates 21 are stacked, the clamping plate 22 is finally placed. The clamping plate 22 is half of an electrode plate 21, and there is no single-layer area in the clamping plate 22.

[0057] After the positive electrode plates 21, the negative electrode plates 21, and the clamping plate 22 are stacked in sequence, the entire electrode group 2 is bent inward into a U shape by bending the single-layer areas of the electrode plates 21, and finally, the forming of the electrode group 2 is completed by hot pressing and shaping. The clamping plate 22 can be a positive electrode plate 21 or a negative electrode plate 21 laminated with the separator 214. Optionally, the clamping plate 22 can also be formed by combining multiple half positive electrode plates 21 and negative electrode plates 21, such as two negative (positive) electrode plates 21 and one positive (negative) electrode plate 21, as long as it is ensured that the finally formed electrode plates 21 are arranged in sequence as positive electrode plates 21, negative electrode plates 21, and separators 214.

[0058] In some embodiments of the present invention, as Figures 6 to 8 shown, the exhaust pin 3 includes: a main body bracket, the main body bracket includes a first plate 31, a second plate 32, and two third plates 33. The two third plates 33 are respectively arranged on both sides of the first plate 31 and are symmetrically arranged; a baffle 34, the baffle 34 is arranged between the two third plates 33 and is spaced from the first plate 31. One end of the second plate 32 (the upper end of the second plate 32 as shown in the figure) is connected to one end of the baffle 34 (the left end of the baffle 34 as shown in the figure), and the baffle 34 and the main body bracket define an air flow channel 35. Thus, the structure of the exhaust pin 3 is simple, which is beneficial to quickly transfer the high-temperature and high-pressure gas generated during the thermal runaway of the lithium-ion battery to the explosion-proof valve 4, preventing the rupture of the housing 1 due to the inability to quickly transfer the high-temperature and high-pressure gas of the thermal runaway inside the electrode group 2.

[0059] Furthermore, as Figure 1 shown, the exhaust pins 3 are located at two vertex corners inside the battery cell 100, which plays a role in quickly transferring gas and prevents the electrode group 2 from moving everywhere inside the housing 1 under the counter shock of the gas, preventing the blockage of the air flow channel 35 and the explosion-proof valve 4.

[0060] In some embodiments of the present invention, the first plate 31 includes a first section and a second section. The first section extends along a first direction, and the second section extends along a second direction perpendicular to the first direction, that is, the first plate 31 is an L-shaped plate. The second plate 32 extends along the second direction, and the first plate 31 and the second plate 32 are fixedly connected by a pin. The other end of the baffle 34 (such as Figure 6The right end of the baffle 34 shown extends in a direction away from the second section in the first direction. In the direction towards the second section, the cross-sectional area of the air flow channel 35 gradually increases. An exhaust channel 36 extending in the second direction is connected to the outlet end of the air flow channel 35. Thus, the structure of the exhaust pin 3 is simple and reliable, and can quickly transfer the high-temperature and high-pressure gas generated during the thermal runaway of the battery cell 100 to the explosion-proof valve 4.

[0061] In some embodiments of the present utility model, each third plate 33 is formed with a chute. The chutes are oppositely arranged, and the width of the chute is not less than the thickness of the baffle 34. As Figure 1 shown, the chute extends along the edge of the third plate 33, and both sides in the width direction of the baffle 34 can just be inserted into the chute and slide. Thus, the overall structural design of the exhaust pin 3 is ingenious and the production cost is low.

[0062] In some embodiments of the present utility model, on the side of the baffle 34 facing away from the air flow channel 35, the baffle 34 and the third plate 33 define a groove, and the width of the groove is not less than the thickness of the electrode group 2. Preferably, the width of the groove is the same as the thickness of the electrode group 2. Thus, the exhaust pin 3 can just be stuck at the position of the avoidance part 25 of the electrode group 2, avoiding the shaking of the exhaust pin 3 in the housing 1 and reducing the risk coefficient of the battery cell 100.

[0063] And, in order to facilitate the installation of the exhaust pin 3, the four corners of the electrode plate 21 are removed during the die-cutting process, as Figure 2 shown in, and the size of the removed part is basically the same as that of the exhaust pin 3. The tab 26 is located at both ends in the length direction of the first plate 211 and the third plate 213 and is close to the position where the second plate 212 is located, and is generated by the extension of the current collector. For the current collector of the positive electrode plate 21, aluminum foil is selected, and for the current collector of the negative electrode plate 21, copper foil is selected.

[0064] Since the polypropylene material has good high-temperature resistance, the first plate 31 is made of polypropylene material and is integrally injection-molded; and, the baffle 34 is made of mica material, ensuring that the exhaust pin 3 can withstand high temperature and high-pressure impacts.

[0065] In some embodiments of the present utility model, the battery cell 100 further includes: an explosion-proof valve 4 and a cover plate 5. The cover plate 5 is provided at both ends of the housing 1 and an explosion-proof port 51 is formed on the cover plate 5. The explosion-proof valve 4 is provided at the position of the explosion-proof port 51, as Figure 9 and Figure 10 shown, the explosion-proof valve 4 includes: a support member 41, a connecting member 42 and a plugging prevention member 43. The support member 41 includes two arc-shaped plates protruding towards opposite directions, and the support member 41 is connected to the cover plate 5. Thus, it prevents the solid waste generated during the thermal runaway of the battery cell 100 from blocking the explosion-proof valve 4 and avoids the occurrence of dangerous situations.

[0066] In some embodiments of the present utility model, the connecting member 42 is connected between the supporting member 41 and the anti-blocking member 43. The surface of the anti-blocking member 43 away from the connecting member 42 bulges in the direction away from the connecting member 42, and the projected area of the anti-blocking member 43 on the cover plate 5 is larger than the area of the explosion-proof port 51. Thus, the exhaust distance inside the explosion-proof valve 4 is increased, the internal gas is differentiated and reformed, the mutual obstruction of the gas inside the housing 1 is reduced, so that the gas can be discharged more quickly and orderly, and the direct impact of the solid waste in the gas on the inside of the explosion-proof valve 4 is blocked, preventing the solid waste from accumulating at the position of the explosion-proof port 51 and blocking the gas discharge.

[0067] In some embodiments of the present utility model, the explosion-proof valve 4 further includes a packaging film 44, and the packaging film 44 seals the explosion-proof port 51. When the internal air pressure reaches a certain limit, the packaging film 44 opens for internal gas discharge, prompting the gas to be discharged more quickly and orderly.

[0068] Preferably, the supporting member 41, the connecting member 42 and the anti-blocking member 43 are all made of high-temperature-resistant aluminum material or stainless steel material; and the packaging film 44 is made of aluminum material.

[0069] Further, the explosion-proof valve 4 is provided on the cover plate 5 and near the position where the second sheet 212 of the electrode group 2 is located. In this way, the exhaust capacity of the battery cell 100 is increased.

[0070] In some embodiments of the present utility model, the battery cell 100 further includes: an electrolyte, the electrolyte is filled in the accommodation cavity, and the electrolyte includes: 15% ethylene carbonate, 45% dimethyl carbonate, 25% ethyl methyl carbonate and an additive. That is to say, the addition amount of ethylene carbonate (EC) in the solvent is appropriately reduced to reduce the heat generation and gas generation of the lithium-ion battery during thermal runaway, and the formation of the lithium-ion battery film is consolidated by increasing vinylene carbonate (VC) to reduce the impact on the electrical performance.

[0071] Specifically, the solvent ratio is 15% ethylene carbonate (EC), 45% dimethyl carbonate (DMC), 25% ethyl methyl carbonate (EMC) and 1% other esters and linear ester mixed solvents, and the additive is 3% vinylene carbonate (VC) and 1% other functional additives. Preferably. The lithium salt is a mixture of inorganic and organic lithium salts, specifically 6% lithium hexafluorophosphate (LiPF6) and 4% lithium bis(fluorosulfonyl)imide (LiFSI). Thus, by appropriately reducing the addition amount of ethylene carbonate (EC) in the solvent to reduce the heat generation and gas generation of the lithium-ion battery cell 100 during thermal runaway, by increasing vinylene carbonate (VC) to consolidate the formation of the lithium-ion battery film to reduce the impact on the electrical performance, and by using two lithium salts in combination to synthesize the characteristics of the lithium salt, the comprehensive characteristics of the electrolyte are ensured, and the matching degree with the double-high goals of the electrical performance and safety performance of the lithium-ion battery cell 100 is improved.

[0072] Next, reference will be made toFigures 1 - 10 Describe a battery cell 100 according to a specific embodiment of the present utility model.

[0073] Specifically, as Figures 1 to 10 shown, when the electrode group 2 is put into the casing, the opening is arranged in a direction conducive to the rapid discharge of gas. In this embodiment, above the U-shaped opening of the electrode group 2, the position of the explosion-proof valve 4 is also at the upper part of the cover plate 5. When thermal runaway occurs in the internal electrode group 2, a large amount of gas generated is transmitted upward along the U-shaped opening, and then quickly transferred to both sides along the air duct formed by the electrode group 2 and the casing 1. When it reaches the explosion-proof valve 4, the gas will blow open the explosion-proof valve 4 and discharge. In order to make the gas transfer more quickly in the top air duct, an air duct is added to the top of the electrode group 2. Preferably, the width of the top air duct is 2 mm, while the air duct formed naturally without special design at the bottom is about 0.5 mm. The way to increase the air duct can be achieved by reducing the width of the overall electrode plate 21 at the U-shaped opening of the electrode group 2, or by increasing the height of the casing 1.

[0074] A battery pack according to an embodiment of the second aspect of the present utility model includes at least one battery cell 100 according to the above-mentioned first aspect embodiment of the present utility model.

[0075] By providing the battery cell 100 of the above-mentioned first aspect embodiment, the overall performance and energy density of the battery pack are improved, the cycle life is extended, and the safety of the battery pack is enhanced according to the battery pack of the embodiment of the present utility model.

[0076] A power device according to an embodiment of the third aspect of the present utility model includes the battery pack according to the above-mentioned second aspect embodiment of the present utility model.

[0077] By providing the battery pack of the above-mentioned second aspect embodiment, the overall performance and energy density of the power device are improved, the safety of the power device is enhanced, and the operation intensity and duration of the power device are ensured according to the power device of the embodiment of the present utility model.

[0078] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.

[0079] In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality of" means two or more unless otherwise specifically defined.

[0080] In the present utility model, unless otherwise clearly stipulated and defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0081] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0082] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present utility model, and the scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that: include: A housing having a receiving cavity formed therein; A pole group, the pole group is arranged in the accommodating cavity, the pole group comprises a pole piece and a clip, the pole piece comprises a first piece, a second piece and a third piece connected in sequence, the first piece and the third piece are stacked and the second piece is bent, and the clip is arranged between the first piece and the third piece; An exhaust pin is arranged in the accommodating cavity, the pole group is formed with an escape portion, and the exhaust pin is arranged at the position of the escape portion.

2. The battery cell according to claim 1, characterized in that: Both ends of the first sheet and both ends of the second sheet are provided with pole ears respectively, the pole sheets are coated with a first coating and a second coating, the first coating is formed between the second coating and the pole sheets, the first sheet and the third sheet are coated with the first coating and the second coating, the second sheet is coated with at least one of the first coating and the second coating, the first coating and the second coating both include conductive materials, and the content of conductive materials in the second coating is 0.5%-1% higher than that in the first coating.

3. The battery cell according to claim 2, characterized in that: The width w of the second sheet satisfies the following relationship with the full length r of the pole sheet and the thickness h of the pole group: w=πr+(h-2r).

4. The battery cell according to claim 1, characterized in that: The electrode sheets include a positive electrode sheet and a negative electrode sheet, the negative electrode sheet is coated with a diaphragm, the edge of the diaphragm exceeds the edge of the negative electrode sheet by at least 1 mm, the diaphragm includes a base film, a protective layer and a coating layer, the base film is made of polypropylene, the protective layer is made of alumina ceramic, and the coating layer is made of polyvinylidene fluoride hexafluoropropylene.

5. The battery cell according to claim 1, characterized in that: The exhaust pin comprises: A main body bracket, the main body bracket comprises a first plate, a second plate and two third plates, the two third plates are respectively arranged on both sides of the first plate and are symmetrically arranged, the first plate comprises a first section and a second section, the first section extends along a first direction, the second section extends along a second direction perpendicular to the first direction, the second plate extends along the second direction, each of the third plates is formed with a slide groove, and the slide grooves are arranged opposite to each other; A baffle, wherein the baffle is arranged between the two third plates and spaced apart from the first plate, one end of the second plate is connected to one end of the baffle, the baffle and the main support define an air flow channel, the other end of the baffle extends in a first direction away from the second section, and in the direction toward the second section, the cross-sectional area of ​​the air flow channel gradually increases, and the thickness of the baffle is not greater than the width of the slide groove.

6. The battery cell according to claim 5, characterized in that: On a side of the baffle away from the airflow channel, the baffle and the third plate define a groove, the width of the groove is not less than the thickness of the pole group, and / or the first plate is made of polypropylene and is integrally injection molded.

7. The battery cell according to claim 1, characterized in that: Also includes: An explosion-proof valve and a cover plate, wherein the cover plate is arranged at both ends of the housing and an explosion-proof opening is formed on the cover plate, and the explosion-proof valve is arranged at the position of the explosion-proof opening, and the explosion-proof valve comprises: A support member, the support member comprising two arc-shaped plates protruding in opposite directions, and the support member is connected to the cover plate; Connectors; an anti-blocking member, wherein the connecting member is connected between the supporting member and the anti-blocking member, a surface of the anti-blocking member on one side away from the connecting member protrudes in a direction away from the connecting member, and a projection area of ​​the anti-blocking member on the cover plate is larger than an area of ​​the explosion-proof opening; A packaging film is provided to cover the explosion-proof opening.

8. A battery pack, characterized in that: The invention comprises at least one battery cell according to any one of claims 1 to 7.

9. A power device, characterized in that: Comprising the battery pack as claimed in claim 8.

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