Single battery and battery pack

Abstract

The utility model relates to the field of lithium batteries, in particular to a single battery and a battery pack. Each single battery has a first direction, a second direction and a third direction which are intersected in pairs, each single battery comprises a shell and a top cover arranged on the shell, and the shell is provided with an anti-explosion hole; an electrode assembly having a side surface; the explosion-proof valve covers and seals the explosion-proof hole; the protective film is provided with a first surface and a second surface which are oppositely arranged in the second direction, the first surface is attached to the side face, a first air guide groove is formed in the second surface in a penetrating mode, and the first air guide groove is communicated with the anti-explosion hole. The embodiment of the utility model has the beneficial effects that the gas generated by the electrode assembly can be smoothly conducted between the top cover side and the explosion-proof valve side of the electrode assembly along the first gas guide groove, so that the gas on the top cover side reaches the explosion-proof valve side and is released by explosion of the explosion-proof valve, and the gas is prevented from being accumulated on the top cover side to cause explosion of the top cover.

Description

TECHNICAL FIELD

[0001] The utility model relates to the battery field, specifically, relate to a single battery and battery package. BACKGROUND

[0002] With the continuous development of new energy industry, the market puts forward higher requirements for the safety performance of power batteries, especially in the safety field, people expect power batteries to be safe enough in daily use, rarely or not to have thermal runaway fire.

[0003] The solution of the explosion-proof valve bottom out (i.e. the positive electrode column is upright and upward, and the explosion-proof valve is on the bottom side of the shell) gradually becomes popular in the market. This bottom-out explosion-proof valve design can quickly release high-temperature gas from the bottom of the electric vehicle when the electrode assembly experiences thermal runaway, greatly ensuring the safety of the passenger cabin and extending the golden time for passengers to escape in the event of thermal runaway.

[0004] However, this bottom-out explosion-proof valve structure design may cause local obstruction due to insufficient exhaust passage from the inner top cover to the explosion-proof valve, and may cause the top cover to explode during thermal runaway, threatening the safety of passengers. UTILITY MODEL CONTENTS

[0005] The utility model aims to provide a single battery and battery package, which can make the gas in the top cover area more smoothly reach the explosion-proof valve area at the bottom, reduce the occurrence of local obstruction, and improve the safety performance of the single battery.

[0006] In a first aspect, the utility model provides a single battery with a first direction, a second direction and a third direction intersecting with each other, which comprises:

[0007] A shell having a receiving cavity, the shell being provided with an explosion-proof hole;

[0008] A top cover connected to the shell and covering the receiving cavity, the explosion-proof hole being provided on the side of the shell away from the top cover;

[0009] An electrode assembly provided in the receiving cavity, the electrode assembly having a side surface;

[0010] An explosion-proof valve covering the explosion-proof hole; and

[0011] A protective film having a first surface and a second surface oppositely arranged along the second direction, the first surface being attached to the side surface, and the second surface being provided with a first air guide groove, the first air guide groove being in communication with the explosion-proof hole.

[0012] In an optional embodiment, the first air guide groove extends along the third direction, and a plurality of the first air guide grooves are provided, and two adjacent first air guide grooves are spaced apart along the first direction.

[0013] The extension direction of the first air guide groove is arranged at an acute angle with the third direction, and a plurality of the first air guide grooves are provided, and two of the first air guide grooves are spaced apart and arranged in parallel or two of the first air guide grooves are arranged in cross.

[0014] In an optional embodiment, the side surface includes a first side surface, a second side surface, and a third side surface, the first side surface and the second side surface are arranged opposite to each other along the second direction, and the third side surface is located between the first side surface and the second side surface.

[0015] The protective film includes a first film part, a second film part, and a first connecting film, the first connecting film connects the first film part and the second film part, the first film part is attached to the first side surface, the second film part is attached to the second side surface, and at least one of the first film part and the second film part is provided with the first air guide groove.

[0016] In an optional embodiment, a plurality of the electrode assemblies are provided, and the plurality of electrode assemblies are arranged in a stack along the second direction, all of the electrode assemblies are located between the first film part and the second film part, and the first film part and the second film part are respectively attached to two electrode assemblies located at the outermost sides in the second direction.

[0017] In an optional embodiment, the first surface of the first connecting film is provided with a plurality of partition ribs, and the partition ribs extend along the third direction; a part of the partition ribs is located between two adjacent electrode assemblies, so that the two adjacent electrode assemblies have a spacing in the second direction and form an exhaust passage.

[0018] In an optional embodiment, in the first direction, the partition rib is convex towards a side away from the second surface, and a second air guide groove is formed in the second surface, and the second air guide groove communicates with the explosion-proof hole.

[0019] In an optional embodiment, the electrode assembly has a second end, the second end is located at an end of the electrode assembly away from the top cover in the third direction; the protective film further includes a bottom film, the bottom film is attached to the second end, and the bottom film is connected with the first film part, the second film part, and the first connecting film; and the bottom film is provided with at least one weak part.

[0020] In an optional embodiment, the monomer battery further has a reference plane perpendicular to the third direction, and a normal projection of the weak part on the reference plane at least partially overlaps a normal projection of the explosion-proof valve on the reference plane.

[0021] In an optional embodiment, a plurality of protrusions are protruded on a side of the first surface towards the electrode assembly, and exhaust grooves are formed between adjacent protrusions, and the protrusions are recessed on the second surface to form the first gas guide groove.

[0022] In a second aspect, the utility model also provides a battery pack, it includes the monomer battery above.

[0023] The utility model embodiment has the advantages of:

[0024] The protective film is attached to the side surface of the electrode assembly, the first gas guide groove is formed through the second surface of the electrode assembly in a back-to-back manner, the first gas guide groove is communicated with the explosion-proof hole, and the top cover side and the explosion-proof valve side in the shell can be communicated; when the electrode assembly is in thermal runaway, the gas generated by the electrode assembly can be smoothly conducted along the first gas guide groove between the top cover side and the explosion-proof valve side of the electrode assembly, and finally gathered in the area of the explosion-proof hole, that is, the area of the explosion-proof valve, so that the gas on the top cover side of the electrode assembly can reach the explosion-proof hole on the explosion-proof valve side through the first gas guide groove, be blown open by the explosion-proof valve, and be released through the explosion-proof hole, thereby avoiding the accumulation of gas on the top cover side and causing the top cover to be blown open, and improving the safety performance of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical scheme of the utility model embodiment, the following will be briefly introduced the drawings needed to be used in the embodiment, it should be understood, the following drawings only show some embodiments of the utility model, therefore should not be regarded as the limitation to the scope, for the ordinary skilled person in the art, under the premise of not paying the creative labor, still can obtain other related drawings according to these drawings.

[0026] Figure 1 The utility model embodiment provides the three-dimensional structure schematic diagram of electrode assembly and protective film;

[0027] Figure 2 The utility model embodiment provides the three-dimensional structure schematic diagram of electrode assembly;

[0028] Figure 3 The utility model embodiment provides the three-dimensional structure schematic diagram of protective film of monomer battery;

[0029] Figure 4 The utility model embodiment provides the first setting mode of protective film and the plan view;

[0030] Figure 5 A plan view of a second setting mode of the protective film provided by the embodiment of the utility model;

[0031] Figure 6 A plan view of a first structure of the electrode assembly and the protective film provided by the embodiment of the utility model;

[0032] Figure 7 A plan view of a second structure of the electrode assembly and the protective film provided by the embodiment of the utility model;

[0033] Figure 8 A perspective structural schematic view of the single battery provided by the embodiment of the utility model;

[0034] Figure 9 A plan view of the single battery provided by the embodiment of the utility model.

[0035] Icon: 1-electrode assembly; 2-protective film; 3-first side; 4-first end; 5-second end; 6-second side; 7-third side; 8-first film part; 9-second film part; 10-first connecting film; 11-second connecting film; 12-first air guide groove; 13-convex part; 14-exhaust groove; 15-separating rib; 16-bottom film; 17-weak part; 18-first surface; 19-second surface; 20-second air guide groove; 21-exhaust passage; 22-housing; 23-top cover. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model.

[0038] It should be noted that: similar labels and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0039] In the description of the utility model, it needs to be explained that, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the utility model product is used, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the utility model. In addition, the terms "first", "second", "third" and the like are only used for differentiation in description and cannot be understood as indicating or implying relative importance.

[0040] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0041] In the description of the utility model, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "set", "mount", "connected", "connected" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0042] The following will be combined Figures 1-9 Some embodiments of the utility model will be described in detail. In the case of no conflict, the following examples and features in the examples can be combined with each other.

[0043] A three-dimensional rectangular coordinate system is established as shown in Figure 1 The coordinate axes involved in the following embodiments are based on this coordinate system.

[0044] In a first aspect, the utility model provides a single battery, which has two perpendicular first direction X, second direction Y and third direction Z, which comprises:

[0045] As shown in Figure 8 The shell 22 has a receiving cavity, and the shell 22 is provided with an explosion-proof hole; the top cover 23 is connected with the shell 22 and covers the receiving cavity, and the explosion-proof hole is arranged on the side of the shell 22 away from the top cover 23.

[0046] The electrode assembly 1 is arranged in the receiving cavity, as shown in Figure 2 The electrode assembly 1 has a side surface;

[0047] The explosion-proof valve is sealed by an explosion-proof valve cover in the explosion-proof hole. In the third direction Z, the explosion-proof valve is located on the side of the electrode assembly 1 away from the top cover 23. And

[0048] The protective film 2, as shown in Figure 3 , Figure 4 and Figure 5 , has a first surface 18 and a second surface 19 arranged opposite along the second direction Y, the first surface 18 is attached to the side surface, and the second surface 19 is provided with a first gas guide groove 12, which is in communication with the explosion-proof hole.

[0049] It should be noted that the second surface 19 is provided with the first gas guide groove 12, wherein "through" means that the second surface 19 has a first edge and a second edge arranged opposite along the third direction Z, and the first gas guide groove 12 has two end portions in the extension direction, one of which extends to the first edge, and the other extends to the second edge, to establish a channel for gas flow between the first edge and the second edge, that is, the first gas guide groove 12, so that the first gas guide groove 12 can guide the gas at the first edge and the gas at the second edge.

[0050] In this embodiment, the part inside the shell 22 is mainly composed of two parts of the electrode assembly 1 and the protective film 2.

[0051] The electrode assembly 1 is the core structure of the single battery, which has two ends in the third direction Z, that is, the first end 4 and the second end 5, and the first end 4 and the top cover 23 can have a first gap to accommodate the tab, current collector and other components of the electrode assembly 1, and the second end 5 and the explosion-proof valve can have a second gap, which is in communication with the explosion-proof hole, so that the gas can gather at the location of the explosion-proof valve, and the explosion-proof valve will burst when the set value is reached.

[0052] In this embodiment, the shape of the electrode assembly 1 can be cylindrical or square, etc., and the specific shape depends on the design requirements and application scenarios of the single battery.

[0053] The protective film 2: the protective film 2 is a thin film covering the side surface of the electrode assembly 1, which has two surfaces along the second direction Y, that is, the first surface 18 and the second surface 19. The first surface 18 of the protective film 2 is closely attached to the side surface of the electrode assembly 1, which plays a role in protecting and sealing the internal structure of the single battery. The second surface 19 of the protective film 2 is provided with the first gas guide groove 12, which is in communication with the explosion-proof hole.

[0054] Specifically, in the present embodiment, the first surface 18 of the protective film 2 is closely attached to the side surface of the electrode assembly 1 to protect the single battery from the external environment; the second surface 19 of the protective film 2 is provided with the first gas guide groove 12, which can be arranged according to the specific design and requirements of the single battery.

[0055] In the present embodiment, the first gas guide groove 12 can be linear, curved or any other shape. Since the first gas guide groove 12 is in communication with the explosion-proof hole, the first gas guide groove can guide the gas in the area where the top cover 23 is located to the side of the explosion-proof valve, and then to the position of the explosion-proof hole, preventing the gas from not reaching the explosion-proof hole and causing the top cover to burst open.

[0056] In the present embodiment, the shape of the first gas guide groove 12 can be any one of a rectangle, a triangle, a semicircle, a trapezoid, etc., or a combination of several of them.

[0057] In the present embodiment, the shapes of all the first gas guide grooves 12 can be completely the same, completely different, or partially the same and partially different.

[0058] In the manufacturing process, the electrode assembly 1 is first manufactured into a shape, and then the protective film 2 is attached to the side surface of the electrode assembly 1 according to design requirements. The protective film 2 can be fixed on the electrode assembly 1 by hot pressing, adhesion or other appropriate methods. When the single battery experiences thermal runaway, the gas can pass through the first gas guide groove 12 from the side of the top cover 23 of the single battery to the side of the explosion-proof valve to prevent the gas from accumulating on the side of the top cover 23.

[0059] In an alternative embodiment, the first gas guide groove 12 extends in the third direction Z, and there are a plurality of first gas guide grooves 12, and two adjacent first gas guide grooves 12 are arranged in the first direction X.

[0060] In another embodiment, the first gas guide groove 12 extends in a direction that forms an acute angle with the third direction Z, and there are a plurality of first gas guide grooves 12, and two of them are arranged in parallel or two of them are arranged in a cross shape.

[0061] In the present embodiment, the number of first gas guide grooves 12 on the protective film 2 is set to be multiple, which can improve the efficiency of gas guiding and help to disperse the gas flow and reduce the accumulation of gas in the area of the top cover 23 inside the single battery.

[0062] When the number of first gas guide grooves 12 is multiple, it can have at least the following two alternative layout methods to improve the efficiency of gas flow inside the single battery:

[0063] The first: extending in the third direction Z.

[0064] The first gas guide groove 12 extends along the third direction Z, and the length of such first gas guide groove 12 is the shortest, which can ensure that the gas can smoothly reach the explosion-proof hole on the side of the explosion-proof valve from the top cover 23 side of the electrode assembly 1 along the shortest path.

[0065] The second kind is arranged at an acute angle with the third direction Z.

[0066] The first gas guide groove 12 is arranged at an acute angle with the third direction Z, which increases the length of the first gas guide groove 12, increases the gas flow path, and also increases the gas capacity.

[0067] In the second arrangement of the first gas guide groove 12, it can also be divided into two layout modes. One is that the length directions of all first gas guide grooves 12 are parallel to each other, that is, they are arranged at the same angle. The other is that the inclination angles of some first gas guide grooves 12 are different, so that the first gas guide grooves 12 with two different inclination angles intersect with each other to form an intersecting gas guide path.

[0068] It should be noted that the above two arrangement modes can be selected according to the specific design and needs of the single battery to achieve the best gas discharge effect.

[0069] It should be noted that the arrangement and layout of the first gas guide groove 12 can be the above-mentioned modes, but it is not limited to the above-mentioned modes. It can also be other arrangement modes, such as extending in an arc-shaped path or an S-shaped path, as long as it can ensure the exhaust effect.

[0070] In an optional embodiment, the side surface includes a first side surface 3, a second side surface 6, and a third side surface 7, the first side surface 3 and the second side surface 6 are oppositely arranged along the second direction Y, and the third side surface 7 is located between the first side surface 3 and the second side surface 6.

[0071] The protective film 2 includes a first film part 8, a second film part 9, and a first connecting film 10, the first connecting film 10 connects the first film part 8 and the second film part 9, the first film part 8 is attached to the first side surface 3, the second film part 9 is attached to the second side surface 6, and at least one of the first film part 8 and the second film part 9 is provided with the first gas guide groove 12.

[0072] In this embodiment, the first film part 8, the second film part 9, and the first connecting film 10 are respectively attached to the first side surface 3, the second side surface 6, and the third side surface 7, which can more comprehensively protect the electrode assembly 1.

[0073] Specifically, in this embodiment, the first gas guide groove 12 can be arranged only on the first film part 8, only on the second film part 9, or on both the first film part 8 and the second film part 9 to increase the exhaust effect.

[0074] In an optional embodiment, the plurality of electrode assemblies 1 are arranged in a stacked manner along the second direction Y, and all the electrode assemblies 1 are located between the first film portion 8 and the second film portion 9, and the first film portion 8 and the second film portion 9 are respectively attached to the two electrode assemblies 1 located at the outermost sides in the second direction Y.

[0075] In the arrangement manner in this embodiment, the plurality of electrode assemblies 1 are arranged in a stacked manner, and the protective film 2 forms an integral whole, that is, the first film portion 8 and the second film portion 9 are respectively attached to the outermost sides of the two electrode assemblies 1 located at the outermost sides in the second direction Y, and the two first connecting films 10 in the X direction are connected to form an integral protective film 2, and all the stacked electrode assemblies 1 are arranged to form an integral whole.

[0076] In an optional embodiment, as shown in Figure 6 and Figure 7 , the first surface 18 of the first connecting film 10 is provided with a plurality of partitioning ribs 15 extending along the third direction Z, and a part of the partitioning ribs 15 is located between the adjacent two electrode assemblies 1, so that the adjacent two electrode assemblies 1 have a certain spacing in the second direction Y and form an exhaust passage 21.

[0077] In this embodiment, a part of the partitioning ribs 15 is located between the adjacent two electrode assemblies 1, which makes the adjacent two electrode assemblies 1 have a certain spacing in the second direction Y, thereby forming the exhaust passage 21.

[0078] The exhaust passage 21 formed between the adjacent two electrode assemblies 1 by the partitioning ribs 15 can help the gas flow between the plurality of electrode assemblies 1 in the single battery, reduce the accumulation of internal pressure of the single battery, and improve the safety of the single battery. In particular, in the case of overheating or other abnormal conditions of the single battery, the internal pressure of the single battery can be effectively controlled, and the occurrence of safety accidents can be reduced.

[0079] At the same time, the partitioning ribs 15 can also serve as positioning features to improve assembly accuracy and ensure correct alignment of the electrode assemblies 1 during stacking.

[0080] In this embodiment, the arrangement of the partitioning ribs 15 allows the electrode assemblies 1 to have a certain flexibility, that is, the electrode assemblies 1 have a certain activity gap without affecting the overall structure of the single battery, which helps to absorb the expansion or contraction caused by temperature changes.

[0081] In this embodiment, the number of partitioning ribs 15 is set according to the number of electrode assemblies 1, and the partitioning ribs 15 are arranged between any adjacent two electrode assemblies 1, that is, the number of partitioning ribs 15 on a single first connecting film 10 is one less than the number of electrode assemblies 1.

[0082] In this embodiment, combined with Figure 2 and Figure 3 As shown, the electrode assembly also has a fourth side surface. The third side surface 7 and the fourth side surface are arranged opposite to each other along the first direction X, and the fourth side surface is also located between the first side surface 2 and the second side surface 6. The first side surface 2, the third side surface 7, the second side surface 6 and the fourth side surface are connected in sequence.

[0083] In this embodiment, the protective film also has a second connecting film 11, which connects the first film portion 8 and the second film portion 9. The second connecting film 11 is arranged opposite to and symmetrically with the first connecting film 10, and the first film portion 8, the first connecting film 10, the second film portion 9 and the second connecting film 11 are connected in sequence.

[0084] Specifically, in this embodiment, the second connecting membrane 11 is also provided with a partition 15, and the partition 15 on the second connecting membrane 11 is provided in a corresponding manner to the partition 15 on the first connecting membrane 10.

[0085] In this embodiment, the protective film is made of mylar film.

[0086] It is understood that in this embodiment, the protective film is made of mylar film, but it is not limited to mylar film alone; it can also be other materials that can protect the electrode assembly.

[0087] In alternative implementations, such as Figure 5 As shown, in the first direction X, the rib 15 protrudes toward the side away from the second surface 19, and a second air guide groove 20 is formed on the second surface 19, which is connected to the explosion-proof hole.

[0088] In this embodiment, the second gas guide groove 20 provides an additional gas flow path. Combined with the first gas guide groove 12, it can more effectively guide the gas and improve the efficiency of gas flow towards the explosion-proof valve side.

[0089] In this embodiment, the second air guide groove 20 is connected to the explosion-proof hole, which helps to balance the pressure distribution inside the electrode assembly 1 and reduce the possibility of the top cover bursting open due to uneven pressure.

[0090] In this embodiment, the rib 15 can be achieved through different manufacturing processes, such as injection molding, extrusion molding, folding molding, etc.

[0091] In an optional embodiment, the electrode assembly 1 has a second end 5, which is located at the end of the electrode assembly 1 that is away from the top cover 23 in the third direction Z; the protective film 2 also includes a bottom film 16, which is attached to the second end 5 and is connected to the first film portion 8, the second film portion 9 and the first connecting film 10; the bottom film 16 is provided with at least one weak portion 17.

[0092] In the present embodiment, the second end 5 of the electrode assembly 1 is also protected by the setting of the bottom film 16, which together with the first film part 8, the second film part 9 and the first connecting film 10 provides all-round protection for the single battery, enhancing the overall protection performance of the electrode assembly.

[0093] In the present embodiment, the second connecting film 11 is also connected with the bottom film 16, so that the electrode assembly 1 is entirely covered by the protective film 2, achieving complete protection effect.

[0094] In the present embodiment, the bottom film 16 is provided with at least one weak part 17, which can provide a stress release path when the internal pressure of the electrode assembly 1 abnormally rises, preventing the single battery from exploding or being damaged due to excessive internal pressure of the electrode assembly 1.

[0095] The first film part 8, the second film part 9, the first connecting film 10, the second connecting film 11 and the bottom film 16 are connected together to form a cavity with an opening facing the top cover; when the electrode assembly experiences thermal runaway, the gas generated flows along the third direction Z towards the opening side (for example, through the exhaust groove 14 provided on the first surface 18 of the protective film 2), and the opening side is generally located in the area of the top cover 23, i.e. the area of the top cover 23 facing the electrode assembly 1; when the gas reaches the area of the top cover 23, it flows through the first gas guide groove 12 (and the second gas guide groove 20) towards the second end 5 of the electrode assembly 1, and finally reaches the area of the explosion-proof valve, which will burst open when the set pressure is reached. If the gas generated by the single battery is too rapid and cannot be quickly discharged to the area of the explosion-proof valve through the above path, the weak part can first burst open under the action of gas pressure, thereby directly reaching the area of the explosion-proof valve and preventing the top cover 23 from bursting open due to the accumulation of gas in the area of the top cover 23.

[0096] The weak part 17 can accurately control its burst pressure according to the design requirements of the single battery, ensuring that it does not burst before the internal pressure of the single battery reaches the set level, while timely breaking open to release and discharge the gas to the area of the explosion-proof valve when the pressure is too high.

[0097] The integrated setting of the bottom film 16 and the weak part 17 can simplify the manufacturing process, reduce the assembly steps and improve the production efficiency.

[0098] The weak part 17 can be adjusted according to different application scenarios and safety requirements to provide solutions with different burst pressures, increasing the flexibility and adaptability of the single battery design.

[0099] In one embodiment, the monomer battery also has a reference plane perpendicular to the third direction Z, and the orthographic projection of the weak part 17 on the reference plane at least partially coincides with the orthographic projection of the explosion-proof valve on the reference plane. In this way, in the third direction Z, the areas where the weak part 17 and the explosion-proof valve are located correspond, so that the weak part 17 can directly reach the area of the explosion-proof valve after being broken by high-pressure gas, and then realize pressure relief through the explosion of the explosion-proof valve.

[0100] In the present embodiment, the weak part 17 can be a part of the bottom film 16 with a thickness thinner than that of other positions of the bottom film 16, so as to reduce the strength of the bottom film 16 at this position, as shown in Figure 4 The thinner thickness of the weak part 17 can be in the form of a blind hole, Figure 4 the circle in the figure is a blind hole, or a whole transition type thinning, etc.; it can also be provided with a shallow scratch on the weak part 17, as shown in Figure 5 The dashed line in the figure is a shallow scratch, and the weak part 17 can burst at the position of the shallow scratch when the internal pressure of the electrode assembly is too large, so as to release the pressure.

[0101] In the present embodiment, a third gas guide groove can also be provided on the first surface 18 of the bottom film 16, i.e. the surface attached to the electrode assembly 1, and the two ends of the third gas guide groove are connected to the first film part 8 and the second film part 9, so that the gas at the end of the electrode assembly 1 can be discharged through the third gas guide groove and the first gas guide groove 12.

[0102] In summary, the provision of the bottom film 16 and at least one weak part 17 provides comprehensive protection and safety guarantee for the monomer battery; this setting method not only enhances the structural integrity and sealing of the monomer battery, but also improves the safety and reliability of the monomer battery by providing a controllable gas guide path; this setting method can be applied to various battery applications with high safety and reliability requirements, such as electric vehicles, portable electronic devices, etc.

[0103] Through the provision of the bottom film 16 and the weak part 17 thereon, the monomer battery can provide more energy storage while maintaining a small size, and at the same time ensure that the monomer battery can work safely and reliably under various conditions.

[0104] In an optional embodiment, as shown in Figure 4 and Figure 5 A plurality of protrusions 13 are provided on the side of the first surface 18 facing the electrode assembly 1, and the exhaust grooves 14 are formed between adjacent protrusions 13, and the protrusions 13 are recessed on the second surface 19 to form the first gas guide groove 12.

[0105] In the embodiment, the exhaust grooves 14 formed between the adjacent convex portions 13 provide additional gas discharge paths, which can further facilitate the discharge of the gas inside the single battery, reduce the accumulation of the internal pressure of the single battery, prevent the single battery from exploding or being damaged due to the excessive internal pressure, and improve the safety of the single battery.

[0106] The exhaust grooves 14 formed by the convex portions 13 increase the surface area of the protective film 2, reduce the bonding area between the protective film 2 and the electrode assembly 1, facilitate the improvement of the heat dissipation performance of the electrode assembly 1, and reduce the risk of overheating of the single battery during operation.

[0107] Through the above embodiments, the utility model provides an effective gas discharge mechanism, which can improve the safety and reliability of the single battery, and thus can be widely applied to various portable electronic devices, electric vehicles and other occasions requiring power storage and release.

[0108] In the embodiment, the shell 22 and the top cover 23 can be made of aluminum alloy or stainless steel, which has good mechanical strength and corrosion resistance, and can protect the electrode assembly 1 and the explosion-proof valve.

[0109] In a second aspect, the utility model also provides a battery pack comprising the single battery.

[0110] In the embodiment, a plurality of single batteries are arranged side by side or stacked in the battery pack to form a battery module, and the arrangement mode can be customized according to the required voltage and capacity.

[0111] The utility model embodiment has the advantages of:

[0112] The protective film 2 is attached to the side surface of the electrode assembly 1, the first gas guide groove 12 is opened on the second surface 19 of the electrode assembly 1, and the first gas guide groove 12 is communicated with the top cover 23 side and the explosion-proof valve side of the electrode assembly 1 in the third direction Z. When the electrode assembly is in thermal runaway, the gas generated by the electrode assembly 1 can be smoothly conducted along the first gas guide groove 12 between the top cover 23 side and the explosion-proof valve side in the third direction Z, so that the gas on the top cover side of the electrode assembly 1 can reach the explosion-proof valve side through the first gas guide groove 12, and the explosion-proof valve is opened to release the gas, thereby avoiding the accumulation of the gas on the top cover side and causing the top cover to explode, and improving the safety performance of the battery.

[0113] The above is only the preferred embodiment of the utility model, and is not used to limit the utility model. For those skilled in the art, the utility model can have various changes and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A single cell, characterized by, Having a first direction (X), a second direction (Y) and a third direction (Z) intersecting with each other, comprising: A shell (22) having a receiving cavity, the shell (22) is provided with an explosion-proof hole; A top cover (23) connected with the shell (22) and covering the receiving cavity, the explosion-proof hole is located on the side of the shell (22) away from the top cover (23); An electrode assembly (1) provided in the receiving cavity, the electrode assembly (1) has a side surface; An explosion-proof valve covering the explosion-proof hole; and A protective film (2) having a first surface (18) and a second surface (19) oppositely arranged along the second direction (Y), the first surface (18) is attached to the side surface, and the second surface (19) is provided with a first air guide groove (12) penetrating through, the first air guide groove (12) communicates with the explosion-proof hole.

2. The cell according to claim 1, wherein The first air guide groove (12) extends along the third direction (Z), and a plurality of first air guide grooves (12) are provided, and adjacent two first air guide grooves (12) are arranged at intervals along the first direction (X); and / or The extension direction of the first air guide groove (12) is arranged at an acute angle with the third direction (Z), and a plurality of first air guide grooves (12) are provided, and two of them are arranged at intervals in parallel or intersected.

3. The cell according to claim 2, wherein The side surface includes a first side surface (3), a second side surface (6) and a third side surface (7), the first side surface (3) and the second side surface (6) are oppositely arranged along the second direction (Y), and the third side surface (7) is located between the first side surface (3) and the second side surface (6); The protective film (2) includes a first film part (8), a second film part (9) and a first connecting film (10), the first connecting film (10) connects the first film part (8) and the second film part (9), the first film part (8) is attached to the first side surface (3), the second film part (9) is attached to the second side surface (6), and at least one of the first film part (8) and the second film part (9) is provided with the first air guide groove (12).

4. The cell according to claim 3, wherein A plurality of electrode assemblies (1) are provided, and a plurality of electrode assemblies (1) are arranged in layers along the second direction (Y), all the electrode assemblies (1) are located between the first film part (8) and the second film part (9), and the first film part (8) and the second film part (9) are respectively attached to the two electrode assemblies (1) located at the outermost sides in the second direction (Y).

5. The cell according to claim 4, wherein The first surface (18) of the first connecting film (10) is provided with at least one partition rib (15) extending along the third direction (Z); a part of the partition rib (15) is located between adjacent two electrode assemblies (1), so that adjacent two electrode assemblies (1) have a spacing in the second direction (Y) and form an exhaust passage (21).

6. The cell according to claim 5, wherein In the first direction (X), the ribs (15) are convex to a side away from the second surface (19), and the second air guide groove (20) is formed on the second surface (19) and communicates with the explosion-proof hole.

7. The cell according to claim 3, wherein The electrode assembly (1) has a second end (5) located at an end of the electrode assembly (1) away from the top cover (23) in the third direction (Z), and the protective film (2) further comprises a bottom film (16) attached to the second end (5), and the bottom film (16) is connected with the first film part (8), the second film part (9) and the first connecting film (10); the bottom film (16) is provided with at least one weak part (17).

8. The cell according to claim 7, wherein The monomer battery also has a reference plane perpendicular to the third direction (Z), and the orthographic projection of the weak part (17) on the reference plane at least partially coincides with the orthographic projection of the explosion-proof valve on the reference plane.

9. The monobloc cell of any one of claims 2-8, wherein, A plurality of convex parts (13) are convex to a side of the electrode assembly (1) on the first surface (18), and exhaust grooves (14) are formed between adjacent convex parts (13), and the convex parts (13) are concave on the second surface (19) to form the first air guide groove (12).

10. A battery pack, characterized by, The monomer battery comprises the monomer battery of any one of claims 1-9. The monomer battery comprises the monomer battery of any one of claims 1-9.

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