Electrochemical device and electric equipment

Abstract

The application provides an electrochemical device and an electric equipment. The electrochemical device comprises a shell, a conductive part, an electrode assembly and an insulating part. The shell has a first wall provided with a first through hole. The conductive part covers the first through hole. The electrode assembly is accommodated in the shell and electrically connected with the conductive part. The insulating part is arranged between the conductive part and the first wall and has a second through hole. In the first direction, at least a part of the projection of the conductive part is located in the first through hole and the second through hole at the same time. The surface of the first wall facing the conductive part and / or the surface of the conductive part facing the first wall is provided with a convex part. When the pressure inside the electrochemical device reaches a threshold value, the convex part can damage the insulating part and support between the first wall and the conductive part, so as to form a channel between the conductive part and the first wall, which communicates the inside and the outside of the shell. The gas in the shell can be discharged to the outside of the shell through the channel, so as to realize pressure relief of the electrochemical device and reduce the risk of safety accidents caused by thermal runaway of the electrochemical device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to an electrochemical device and an electric equipment. BACKGROUND

[0002] With the development of new energy technology, energy storage devices are increasingly widely used, for example, they can be applied to mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools.

[0003] The electrochemical device as an energy storage device generally generates an electrochemical reaction through an electrode assembly and an electrolyte to output electric energy. For the electrochemical device, safety is one of the main concerns of users. Therefore, how to improve the safety of the electrochemical device is a technical problem to be solved. SUMMARY

[0004] The present application provides an electrochemical device and an electric equipment to improve the safety performance of the electrochemical device.

[0005] In a first aspect, the present application provides an electrochemical device, comprising a shell, a conductive piece, an electrode assembly and an insulating piece. The shell has a first wall, the first wall is provided with a first through hole, the conductive piece covers the first through hole, the electrode assembly is contained in the shell, and the conductive piece is electrically connected with the electrode assembly to lead out one polarity of the electrode assembly. The insulating piece is arranged between the conductive piece and the first wall to insulate and separate the conductive piece and the shell. The insulating piece has a second through hole, and at least a part of the projection of the conductive piece is located in the first through hole and the second through hole at the same time along a first direction, the first direction being the thickness direction of the first wall. Wherein, the surface of the first wall facing the conductive piece and / or the surface of the conductive piece facing the first wall is provided with a convex part.

[0006] In the above technical solution, by providing a convex part on the surface of the conductive piece facing the first wall and / or the surface of the first wall facing the conductive piece, when the pressure inside the electrochemical device reaches a threshold value, the convex part can damage the insulating piece which plays an insulating sealing role, and support between the first wall and the conductive piece, so as to form a channel between the conductive piece and the first wall which communicates the inside and the outside of the shell, the gas in the shell can be discharged from the channel to the outside of the shell, realizing pressure relief of the electrochemical device, reducing the risk of safety accidents caused by thermal runaway of the electrochemical device, and improving the safety performance of the electrochemical device. The above scheme can relieve pressure when the electrochemical device is in thermal runaway without the need to set a pressure relief mechanism (such as a common explosion-proof valve or notch on the shell), so the integrity of the shell structure can be maintained, thereby ensuring the structural strength of the shell and further improving the safety performance of the electrochemical device, while improving the space utilization and energy density of the electrochemical device.

[0007] In some embodiments, the protrusion is arranged on the surface of the conductive member facing the first wall. In the above technical solution, since the conductive member is separately formed, generally in a sheet shape (not excluding local protrusions or recesses), the structure is relatively simple, and the processing convenience and processing cost of arranging the protrusion on the surface of the conductive member facing the first wall are relatively low, thereby reducing the overall cost of the electrochemical device.

[0008] In some embodiments, the conductive member is integrally formed with the protrusion. In the above technical solution, the conductive member and the protrusion can be integrally formed by simple and convenient manufacturing methods such as stamping, milling, casting, etc., and the overall structural strength of the conductive member and the protrusion is better.

[0009] In some embodiments, the electrochemical device includes a plurality of protrusions, and the plurality of protrusions are arranged at intervals around the first through hole. In the above technical solution, the plurality of protrusions are arranged at intervals around the first through hole, so that after the pressure inside the electrochemical device reaches a threshold value, the plurality of protrusions can jointly support the conductive member and the first wall, so that the conductive member and the first wall are subjected to relatively uniform stress, improving the stability of the formed channel and facilitating rapid and stable pressure relief. It is preferable to uniformly distribute the plurality of protrusions to make the stress on the conductive member and the first wall more uniform, and the distribution of the formed pressure relief channel is more uniform, thereby improving the safety of the pressure relief process.

[0010] In some embodiments, one end of the protrusion close to the first through hole protrudes beyond the hole wall of the second through hole, and the other end of the protrusion away from the first through hole protrudes beyond the outer edge of the insulating member or is flush with the outer edge of the insulating member. In the above technical solution, one end of the protrusion close to the first through hole protrudes beyond the hole wall of the second through hole, and the other end of the protrusion away from the first through hole protrudes beyond the outer edge of the insulating member or is flush with the outer edge of the insulating member, so that the protrusion can form a channel along the radial direction of the first through hole after the insulating member is damaged, which is beneficial to more rapid and smooth pressure relief and reduces the risk of safety accidents caused by thermal runaway of the electrochemical device.

[0011] In some embodiments, the electrode assembly includes a first tab and a second tab with opposite polarities, the first tab is electrically connected with the conductive piece, and the second tab is electrically connected with the shell; the protrusion is configured to form a channel between the conductive piece and the first wall after the insulation piece melts, the channel connecting the inside and the outside of the shell. In the above technical solution, the first tab is electrically connected with the conductive piece, and the second tab is electrically connected with the shell, so that the conductive piece and the shell form two poles of the electrochemical device with opposite polarities, respectively. When the pressure inside the electrochemical device increases to a threshold value, the protrusion damages the insulation piece, the electrochemical device is short-circuited, the temperature of the electrochemical device after short-circuiting rises rapidly, the high temperature causes the insulation piece to melt, and the locally melted insulation piece flows to both sides of the protrusion under the action of the gas inside the shell, forming a larger pressure relief channel in cross section, thereby improving the pressure relief efficiency of the electrochemical device when the electrochemical device is in thermal runaway. At the same time, the top of the protrusion must be uneven microscopically, as long as the higher part of the top of the protrusion contacts the shell, a local short circuit heat release occurs, and then the melting of the insulation piece around the protrusion can be realized before the entire insulation piece is completely damaged by the protrusion, thereby accelerating the formation of the pressure relief channel and improving the response sensitivity of the electrochemical device to abnormal increase in internal pressure, reducing the risk of safety accidents caused by thermal runaway of the electrochemical device, and improving the safety performance of the electrochemical device. According to different battery design requirements, the melting of the insulation piece around the protrusion caused by local short circuit can be the main effect of forming the pressure relief channel, for example, when the insulation piece is made of a material with high tear resistance and / or the top of the protrusion is not sharp, etc., the pressure required to damage the insulation piece by the protrusion is too large to ensure safety, and at this time, the local short circuit heat release caused by the protrusion between the conductive piece and the shell can form a pressure relief channel in the electrochemical device under lower internal pressure, thereby achieving safe pressure relief.

[0012] In some embodiments, the protrusion is formed with a groove on the surface of the insulating member along the first direction to form a weak part. The protrusion is inserted into the groove and abuts against the weak part, and the protrusion is configured to break the weak part when the internal pressure of the shell reaches a threshold value, so as to short the conductive member and the shell. In the above technical solution, after the protrusion breaks the insulating member, the protrusion is supported between the conductive member and the first wall, the conductive member and the shell are shorted through the protrusion, the temperature of the electrochemical device rises rapidly, and the high temperature causes the insulating member to melt, so that the protrusion supported between the conductive member and the first wall can form a channel between the conductive member and the first wall to communicate the inside and the outside of the shell, or the protrusion allows the molten insulating member to be extruded from between the conductive member and the first wall by the gas in the inside of the electrochemical device, so as to form a channel between the conductive member and the first wall, and the pressure is released through the channel, thereby reducing the risk of safety accidents caused by thermal runaway of the electrochemical device and improving the safety performance of the electrochemical device. By breaking the weak part when the internal pressure of the shell reaches a threshold value, the protrusion short-circuits the conductive member and the shell, which can release the pressure of the electrochemical device without the need to set a pressure relief mechanism on the shell, and can not damage the integrity of the shell structure, thereby ensuring the structural strength of the shell. The weak part is provided to make the insulating member more easily broken by the protrusion, so as to achieve short-circuiting of the electrochemical device in time and timely pressure relief.

[0013] In some embodiments, the thickness of the weak part is D, and 0.01mm≤D≤0.50mm. In the above technical solution, if the thickness D of the weak part is too small, for example, less than 0.01mm, the weak part is easily damaged by the protrusion or the protrusion easily causes a local short circuit between the conductive member and the shell, and the electrochemical device is too sensitive to internal pressure changes, causing performance waste; if the thickness D of the weak part is too large, for example, greater than 0.50mm, that is, the insulating member between the top of the protrusion and the first wall of the shell is too thick in the normal state of the electrochemical device, and the protrusion can completely damage the insulating member or achieve a local short circuit only under a very large pressure, which makes the pressure threshold too high and is not conducive to ensuring the safety of the electrochemical device. The thickness D of the weak part satisfies 0.01mm≤D≤0.50mm, so that the weak part has good insulation performance and is more easily broken by the protrusion, to ensure timely pressure relief when the internal pressure of the electrochemical device is too large.

[0014] In some embodiments, the protrusion extends in a straight line or a curve on the surface of the first wall facing the conductive member and / or the surface of the conductive member facing the first wall, and the cross section of the protrusion is triangular. In the above technical solution, the cross section of the protrusion is triangular, so that the top of the protrusion is more sharp and can more easily break the insulating member. According to design needs, the cross section of the protrusion can also be other shapes in other embodiments, such as curved triangular, elliptical, etc.

[0015] In some embodiments, the height of the cross section of the convex part is H, the width of the cross section of the convex part is L, and 1 / 5≤H / L≤3 is satisfied. In the above technical solution, if H / L is too small, for example, less than 1 / 5, when the cross section of the convex part is a triangle, the triangle is too flat and has low sharpness, and it is difficult to pierce the insulating part, thereby making it difficult to form a smooth pressure relief channel. If H / L is too large, for example, greater than 3, the cross section of the convex part is too sharp, and the insulating part can be pierced at a lower pressure. In addition, due to the sharp end discharge effect, the convex part is also more likely to cause a local short circuit between the conductive part and the first wall, so that the electrochemical device is relieved at a lower internal pressure, causing performance waste. 1 / 5≤H / L≤3, so that the electrochemical device can be relieved at a reasonable internal pressure, the convex part can break the insulating part, and a channel formed between the first wall and the conductive part can meet the pressure relief requirements of the electrochemical device, so that the electrochemical device can be relieved in time and quickly, and the risk of safety accidents caused by thermal runaway of the electrochemical device is reduced.

[0016] In some embodiments, the height of the convex part is H, and the thickness of the insulating part is K, and 0.01mm≤H<K is satisfied. In the above technical solution, the height H of the convex part and the thickness K of the insulating part satisfy 0.01mm≤H<K, so that the insulating part has good insulation performance, and the convex part can support the first wall and the conductive part in the thickness direction of the first wall after breaking the insulating part, so that a channel with a large cross-sectional area is formed between the first wall and the conductive part for pressure relief, to meet the pressure relief requirements.

[0017] In some embodiments, the conductive part can also cover the first through hole from the side of the first wall facing the electrode assembly. In the above technical solution, the conductive part covers the first through hole from the side of the first wall facing the electrode assembly, which can prevent the conductive part from occupying the internal space of the shell and improve the energy density.

[0018] In a second aspect, the embodiments of the present application provide a power utilization device, which comprises the electrochemical device provided by any of the embodiments of the first aspect. In the above technical solution, the electrochemical device provided by any of the embodiments of the first aspect has good safety, which can improve the power utilization safety of the power utilization device with the electrochemical device. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope.

[0020] Figure 1 The structural schematic diagram of the electrochemical device provided by some embodiments of the present application;

[0021] Figure 2 The structural schematic diagram of the electrochemical device provided by some embodiments of the present application;

[0022] Figure 3 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0023] Figure 4 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0024] Figure 5 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0025] Figure 6 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0026] Figure 7 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0027] Figure 8 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0028] Figure 9 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0029] Figure 10 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0030] Figure 11 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0031] Figure 12 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0032] Figure 13 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0033] Figure 14 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0034] Figure 15 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0035] Figure 16 Assembled view of a housing, conductive member, and insulating member for some embodiments of the present application;

[0036] Figure 17 Fig. 1 is a schematic view of an electrochemical device according to an embodiment of the present application; Figure 16 Fig. 2 is a sectional view taken along line A-A of Fig. 1 ;

[0037] Figure 18 Fig. 3 is a sectional view taken along line B-B of Fig. 1 ; Figure 17 Fig. 4 is an enlarged view of portion A in Fig. 3;

[0038] Figure 19 Fig. 5 is a schematic view of an electrochemical device according to another embodiment of the present application;

[0039] Figure 20 Fig. 6 is a sectional view taken along line C-C of Fig. 5; Figure 17 Fig. 7 is an enlarged view of portion B in Fig. 6;

[0040] Fig. 8 is a schematic view of an electrochemical device according to still another embodiment of the present application; DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions of the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Generally, the components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application.

[0043] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0044] It should be noted that: similar reference numerals and letters in the following drawings represent similar items, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0045] In the description of the embodiments of the present application, it should be noted that the indicated position or positional relationship is based on the position or positional relationship shown in the drawings, or the position or positional relationship commonly used when the product of the application is placed, or the position or positional relationship commonly understood by those skilled in the art, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular position, be constructed and operated in a particular position, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0046] At present, from the development of market situation, the application of electrochemical devices is more and more widely. Electrochemical devices have been widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, electric tools, unmanned aerial vehicles, energy storage equipment and many other fields. With the continuous expansion of the application field of electrochemical devices, the demand of its market is also increasing.

[0047] The development of electrochemical devices needs to consider many design factors, such as energy density, cycle life, discharge capacity, charge-discharge rate and other performance parameters, in addition, the safety of electrochemical devices also needs to be considered.

[0048] For electrochemical devices, the main safety hazard comes from the charging and discharging process. When abnormal reaction occurs in the electrochemical device, a large amount of gas will be generated. In order to effectively avoid unnecessary loss, the electrochemical device sets a pressure relief mechanism, which is one of the protection measures for the electrochemical device.

[0049] The pressure relief mechanism refers to an element or component that is destroyed to release the internal pressure when the internal pressure or temperature of the electrochemical device reaches a threshold value. The threshold value is designed differently according to different design requirements. The threshold value may depend on the material of one or several of the positive plate, negative plate, electrolyte and separator film in the electrochemical device. The pressure relief mechanism can take the form of an explosion-proof valve, an explosion-proof sheet, a gas valve, a pressure relief valve or a safety valve, and can specifically take the form of a pressure-sensitive or temperature-sensitive element or structure, that is, when the internal pressure or temperature of the electrochemical device reaches the threshold value, the pressure relief mechanism performs an action or the pressure relief mechanism structure is destroyed, thereby forming an opening or passage for the internal pressure or temperature to be released.

[0050] "Actuated" as referred to in the present application means that the pressure relief mechanism is activated or is in a state of action, so that the internal pressure and temperature of the electrochemical device can be released. The action of the pressure relief mechanism can include, but is not limited to, at least one of the following: the pressure relief mechanism is broken, cracked, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substance in the interior of the electrochemical device is discharged as an exhaust from the actuated part. In this way, the electrochemical device can be depressurized and cooled at a controllable pressure or temperature, so as to avoid potential more serious accidents such as explosion.

[0051] The exhaust from the electrochemical device as referred to in the present application includes, but is not limited to, the electrolyte, the positive and negative electrode sheets dissolved or split, the fragments of the separator, the high-temperature and high-pressure gas generated by the reaction, the flame, etc.

[0052] The electrochemical device includes a housing and an electrode assembly arranged in the housing. The pressure relief mechanism is a weak area or a pressure relief valve arranged on the housing, which is broken to release the pressure in the electrochemical device when the pressure in the electrochemical device reaches a threshold value. Arranging the weak area or the pressure relief valve on the housing increases the processing technology of the housing, and the process of arranging the weak area and the pressure relief valve on the housing is difficult. Arranging the weak area or the pressure relief valve on the housing also damages the integrity of the structure of the housing and affects the overall structural strength of the housing, thereby reducing the safety of the electrochemical device. At the same time, arranging the pressure relief valve occupies the internal space of the housing of the electrochemical device, reduces the space utilization and the energy density.

[0053] Based on the above considerations, in order to alleviate the problem that the integrity of the structure of the housing is damaged and the overall structural strength of the housing is affected due to the formation of the weak area on the housing, thereby reducing the safety of the electrochemical device. The embodiments of the present application provide an electrochemical device, which includes a housing, a conductive part, an electrode assembly and an insulating part; the housing has a first wall, and the first wall is provided with a first through hole; the conductive part covers the first through hole; the electrode assembly is contained in the housing, and the conductive part is electrically connected with the electrode assembly to lead out one polarity of the electrode assembly; the insulating part is arranged between the conductive part and the first wall to insulate and separate the conductive part and the housing, and the insulating part has a second through hole; in the first direction, at least a part of the projection of the conductive part is located in the first through hole and the second through hole at the same time, and the first direction is the thickness direction of the first wall; the surface of the first wall facing the conductive part and / or the surface of the conductive part facing the first wall is provided with a convex part.

[0054] By arranging the protrusions on the surface of the conductive member facing the first wall and / or the surface of the first wall facing the conductive member, when the pressure inside the electrochemical device reaches a threshold value, the protrusions can break the insulating member and support between the first wall and the conductive member to form a channel between the conductive member and the first wall to communicate the inside and the outside of the housing, so that the gas in the housing can be discharged from the channel to the outside of the housing, realizing pressure relief of the electrochemical device, reducing the risk of safety accidents caused by thermal runaway of the electrochemical device, and improving the safety performance of the electrochemical device. The above scheme can relieve pressure when the electrochemical device is in thermal runaway without the need to set a pressure relief mechanism on the housing, so the integrity of the housing structure can be maintained to ensure the structural strength of the housing and further improve the safety performance of the electrochemical device.

[0055] The electrochemical device disclosed in the embodiments of the present application can be used in electric two-wheeled vehicles, power tools, unmanned aerial vehicles, energy storage devices and other electric devices. The electrochemical device with the working condition of the present application can also be used as a power supply system of an electric device, which is conducive to improving the charging and discharging safety of the power supply system and the power consumption safety of the electric device.

[0056] The embodiments of the present application provide an electric device using an electrochemical device as a power supply. The electric device can be but is not limited to electronic devices, power tools, electric vehicles, unmanned aerial vehicles, and energy storage devices. The electronic devices can include mobile phones, tablets, laptops, etc., the power tools can include electric drills, electric saws, etc., and the electric vehicles can include electric cars, electric motorcycles, electric bicycles, etc.

[0057] As shown in Figure 1 , Figure 2 The embodiments of the present application provide an electrochemical device 100, which includes a housing 10, a conductive member 20, an electrode assembly 30, and an insulating member 40. The housing 10 has a first wall 11 provided with a first through hole 111. The conductive member 20 covers the first through hole 111. The electrode assembly 30 is contained in the housing 10, and the conductive member 20 is electrically connected with the electrode assembly 30 to lead out one polarity of the electrode assembly 30. The insulating member 40 is arranged between the conductive member 20 and the first wall 11 to insulate and separate the conductive member 20 and the housing 10. The insulating member 40 has a second through hole 41. In the first direction X, which is the thickness direction of the first wall, at least a part of the projection of the conductive member 20 is located in the first through hole 111 and the second through hole 41 at the same time. The surface of the first wall 11 facing the conductive member 20 and / or the surface of the conductive member 20 facing the first wall 11 is provided with protrusions 50.

[0058] Please continue to see Figure 1 , Figure 2The housing 10 forms a receiving space for receiving the electrode assembly 30. The housing 10 includes a first wall 11 and a housing body 12 having an opening 121, and the first wall 11 covers the opening 121 of the housing body 12.

[0059] In the first direction X, the conductive member 20, the insulating member 40, and the first wall 11 are stacked, and the insulating member 40 is stacked between the conductive member 20 and the first wall 11 to insulate and separate the conductive member 20 and the first wall 11. The first through hole 111 and the second through hole 41 communicate in the first direction X. The conductive member 20 covers the first through hole 111 on the side of the insulating member 40 away from the first wall 11. The first direction is parallel to the first direction X.

[0060] The shapes of the first through hole 111 and the second through hole 41 can be various, such as square holes, rectangular holes, circular holes, etc. The shapes of the first through hole 111 and the second through hole 41 can be the same or different. In the present embodiment, the first through hole 111 and the second through hole 41 are both circular holes, and the first through hole 111 and the second through hole 41 are coaxially arranged.

[0061] In the embodiment in which the first through hole 111 and the second through hole 41 are both circular holes, the diameters of the first through hole 111 and the second through hole 41 can be the same or different. Figure 1 、 Figure 2 A preferred case in which the second through hole 41 and the first through hole 111 are coaxially arranged and the diameter of the second through hole 41 is greater than the diameter of the first through hole 111 is shown in FIG. 2.

[0062] In some embodiments, the housing 10 can include one first wall 11, and the housing body 12 has one opening 121, and the first wall 11 covers the opening 121. In other embodiments, the housing 10 can include two first walls 11 arranged opposite to each other, and the housing body 12 has two openings 121, and the two openings 121 can be located at opposite ends of the housing body 12, and each first wall 11 is used to cover one opening 121. Figure 1 、 Figure 2 A case in which the housing 10 includes one first wall 11 is shown in FIG. 1.

[0063] The electrode assembly 30 is composed of a positive electrode tab (not shown in the figure), a negative electrode tab (not shown in the figure), and a separator (not shown in the figure). The electrochemical device 100 mainly relies on the movement of metal ions between the positive electrode tab and the negative electrode tab to work. The positive electrode tab includes a positive electrode current collector and a positive electrode active material layer coated on the surface of the positive electrode current collector. In some embodiments, the positive electrode current collector also has a portion that is not coated with the positive electrode active material layer, the positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode current collector that is coated with the positive electrode active material layer, and the positive electrode current collector that is not coated with the positive electrode active material layer serves as a positive electrode tab. In other embodiments, the positive electrode tab can also be a structure that is provided separately from the positive electrode current collector and is electrically connected. Taking the electrochemical device 100 as a lithium ion battery for example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode tab includes a negative electrode current collector and a negative electrode active material layer coated on the surface of the negative electrode current collector. In some embodiments, the negative electrode current collector also has a portion that is not coated with the negative electrode active material layer, the negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the negative electrode current collector that is coated with the negative electrode active material layer, and the negative electrode current collector that is not coated with the negative electrode active material layer serves as a negative electrode tab. In other embodiments, the negative electrode tab can also be a structure that is provided separately from the negative electrode current collector and is electrically connected. The material of the negative electrode current collector can be copper, and the negative electrode active material can be common negative electrode active materials containing carbon and / or silicon, such as natural graphite, activated carbon, hard carbon, artificial graphite, carbon-silicon compounds, etc. In order to ensure that no fusing occurs when passing a large current, the number of positive electrode tabs is multiple and they are stacked together, and the number of negative electrode tabs is multiple and they are stacked together. The positive electrode tab and the negative electrode tab are respectively the first electrode tab 31 and the second electrode tab 32 mentioned later.

[0064] The positive electrode tab and the negative electrode tab can extend from the same end of the electrode assembly 30, or can extend from opposite ends of the electrode assembly 30 respectively. Figure 1 、 Figure 2 All show the case where the positive electrode tab and the negative electrode tab extend from opposite ends of the electrode assembly 30 respectively. Among them, Figure 1 shows the case where the positive electrode tab and the negative electrode tab extend from the electrode assembly 30 along the first direction X respectively, Figure 2 shows the case where the positive electrode tab and the negative electrode tab extend from the direction perpendicular to the first direction X of the electrode assembly 30 respectively.

[0065] One of the positive electrode tab and the negative electrode tab is electrically connected to the conductive member 20, so as to realize the electrical connection between the conductive member 20 and the electrode assembly 30.

[0066] The material of the isolation film can be PP (polypropylene) or PE (polyethylene) or the like. In addition, the electrode assembly 30 can be in a roll structure or in a stack structure, and the embodiments of the present application are not limited in this respect.

[0067] The electrochemical device 100 can include one conductive member 20 or two conductive members 20.

[0068] As shown in FIG. 1, the electrochemical device 100 can include one conductive member 20 or two conductive members 20. Figure 3 Figure 4 In the embodiment in which the housing 10 includes two first walls 11, the electrochemical device 100 can include two conductive members 20, and the two conductive members 20 cover the first through holes 111 of the two first walls 11 respectively. An insulating member 40 is arranged between each first wall 11 and the corresponding conductive member 20 to insulate and separate them. The positive and negative tabs can be electrically connected to the two conductive members 20 respectively, and the two conductive members 20 can lead out two opposite polarities of the electrode assembly 30 respectively, and the two conductive members 20 can form the positive and negative electrodes of the electrochemical device 100 respectively, so that the electrochemical device 100 can be charged and discharged through the positive and negative electrodes.

[0069] As shown in FIG. 1, the electrochemical device 100 can include one conductive member 20 or two conductive members 20. Figure 5 Figure 6 In the embodiment in which the electrochemical device 100 includes one conductive member 20 and one first wall 11, the conductive member 20 is arranged on the first wall 11 of the housing 10 in an insulating manner. One of the positive and negative tabs is electrically connected to the conductive member 20, and the other is electrically connected to the housing 10, so that the conductive member 20 and the housing 10 can lead out two opposite polarities of the electrode assembly 30 respectively, and the conductive member 20 and the housing 10 can form the positive and negative electrodes of the electrochemical device 100 respectively, so that the electrochemical device 100 can be charged and discharged through the positive and negative electrodes. The positive and negative tabs are located at opposite ends of the electrode assembly 30 respectively, which reduces the risk of internal short circuit of the electrochemical device 100. The material of the housing 10 is metal, so that the housing 10 has good structural strength and heat resistance. The material of the housing 10 can be determined according to the polarity of the tab electrically connected thereto. If the positive tab is electrically connected to the housing 10, the material of the housing 10 can be aluminum, and if the negative tab is electrically connected to the housing 10, the material of the housing 10 can be stainless steel or nickel or the like.

[0070] ​​The protrusion 50 can be arranged only on the surface of the conductive member 20 facing the first wall 11, and the protrusion 50 protrudes from the surface of the conductive member 20 facing the first wall 11 in the direction close to the first wall 11 along the first direction X. The protrusion 50 can be arranged only on the surface of the first wall 11 facing the conductive member 20, and the protrusion 50 protrudes from the surface of the first wall 11 facing the conductive member 20 in the direction close to the conductive member 20 along the first direction X. The surface of the first wall 11 facing the conductive member 20 and the surface of the conductive member 20 facing the first wall 11 can both be provided with the protrusion 50.

[0071] The insulating member 40 is arranged between the first wall 11 and the conductive member 20, and the insulating member 40 and the protrusion 50 overlap along the first direction X, so that the protrusion 50 can act on the insulating member 40 along the first direction X, thereby enabling the protrusion 50 to damage the insulating member 40.

[0072] It should be noted that the dashed line in the figure in the present application represents the surface of the conductive member 20 facing the first wall 11 in the first direction X.

[0073] By arranging the protrusion 50 on the surface of the conductive member 20 facing the first wall 11 and / or the surface of the first wall 11 facing the conductive member 20, when the pressure inside the electrochemical device 100 reaches a threshold value, the protrusion 50 can damage the insulating member 40 that plays an insulating sealing role between the conductive member 20 and the first wall 11, and support between the first wall 11 and the conductive member 20, so as to form a channel between the conductive member 20 and the first wall 11, which communicates the inside and the outside of the housing 10, and the gas in the housing 10 can be discharged to the outside of the housing 10 through the channel, thereby achieving pressure relief of the electrochemical device 100, reducing the risk of safety accidents caused by thermal runaway of the electrochemical device 100, and improving the safety performance of the electrochemical device 100. The above-mentioned scheme can achieve pressure relief when the electrochemical device 100 is in thermal runaway without the need to arrange a pressure relief mechanism (such as a common explosion-proof valve or a notch on the housing) on the housing 10, so the integrity of the structure of the housing 10 is not damaged, thereby ensuring the structural strength of the housing 10, further improving the safety performance of the electrochemical device 100, while improving the space utilization and energy density of the electrochemical device 100.

[0074] In some embodiments, as Figures 1-6As shown, the electrochemical device 100 further comprises a body part 60, which is electrically connected with the conductive part 20. The conductive part 20 protrudes radially from the outer periphery of the body part 60 along the first through hole 111. The conductive part 20 and the body part 60 can be provided separately and then connected as a whole structure by welding, bonding or the like to realize the electrical connection between the conductive part 20 and the body part 60. The conductive part 20 and the body part 60 can also be an integrally formed structure, such as formed by stamping, casting or the like. The conductive part 20 and the body part 60 jointly form the pole of the electrochemical device 100. The body part 60 is arranged in the first through hole 111 and the second through hole 41. There is a gap between the outer periphery of the body part 60 and the hole wall of the first through hole 111, and there is a gap between the outer periphery of the body part 60 and the hole wall of the second through hole 41, so as to facilitate the discharge of gas inside the electrochemical device 100.

[0075] In the present embodiment, the conductive part 20 can be a disc structure, and the body part 60 can be a cylindrical structure. In other embodiments, the conductive part 20 can also be other structures, such as rectangular, hexagonal, etc., and the body part 60 can also be other structures, such as a cuboid, a hexagonal prism, etc.

[0076] It is worth noting that the body part 60 is not a necessary component, such as 7 and Figure 8 As shown, the planar conductive part 20 can also serve as the pole of the electrochemical device 100.

[0077] As shown in Figure 3 , Figure 5 The conductive part 20 can be located outside the first wall 11, i.e. the conductive part 20 and the insulating part 40 are both located outside the housing 10, and the body part 60 passes through the second through hole 41 and the first through hole 111 in turn. The conductive part 20 can be electrically connected with the electrode assembly 30 through the body part 60, and the conductive part 20 located outside the housing 10 can be connected with the electric device, the charging device or the like. In this embodiment, the body part 60 can extend to the side of the first wall 11 away from the insulating part 40, so as to realize the electrical connection between the body part 60 and the tab of the electrode assembly 30. Of course, the end of the body part 60 away from the conductive part 20 can also be located inside the first through hole 111. In the embodiment in which the conductive part 20 can be located outside the first wall 11 and the body part 60 is not connected to the conductive part 20 (as shown in Figure 7 The surface of the conductive part 20 facing the first wall 11 can be connected with the tab of the electrode assembly 30, and the surface of the conductive part 20 away from the first wall 11 can be connected with the electric device, the charging device or the like.

[0078] As shown in Figure 4 , Figure 6As shown, the conductive member 20 can be located inside the first wall 11, i.e. both the conductive member 20 and the insulating member 40 are located inside the housing 10, and the body portion 60 extends through the second through hole 41 and the first through hole 111 in sequence. The conductive member 20 is electrically connected with the electrode assembly 30, and the body portion 60 extends from inside the housing 10 to outside the housing 10, and the body portion 60 can be connected with the electric device, the charging device, etc. In this embodiment, the body portion 60 can extend to the side of the first wall 11 away from the insulating member 40, so as to facilitate the connection between the body portion 60 and the electric device, the charging device, etc. Of course, the end of the body portion 60 away from the conductive member 20 can also be located inside the first through hole 111.

[0079] In the embodiment in which the conductive member 20 can be located inside the first wall 11 and the body portion 60 is not connected to the conductive member 20 (as shown in FIG. 1A), the electric connection portion of the electric device, the charging device, etc. can be connected with the surface of the conductive member 20 facing the first wall 11 by penetrating the first through hole 111 and the second through hole 41. Figure 8 As shown, the electric connection portion of the electric device, the charging device, etc. can be connected with the surface of the conductive member 20 facing the first wall 11 by penetrating the first through hole 111 and the second through hole 41.

[0080] In the embodiment in which the electric chemical device 100 has two first walls 11 and two conductive members 20, as shown, along the first direction X, the two first walls 11 can be oppositely arranged, one conductive member 20 can be located outside the first wall 11, and the other conductive member 20 can be located inside the first wall 11. Figure 9

[0081] As shown, in some embodiments, the convex portion 50 is arranged on the surface of the conductive member 20 facing the first wall 11. Figure 10 As shown, in some embodiments, the convex portion 50 is arranged on the surface of the conductive member 20 facing the first wall 11.

[0082] In the embodiment in which the conductive member 20 is provided with the convex portion 50, the convex portion 50 can be one or more. In the embodiment in which the conductive member 20 is provided with multiple convex portions 50, the multiple convex portions 50 can be arranged in a circumferential direction of the first through hole 111, and a spacing can be formed between two adjacent convex portions 50.

[0083] In the embodiment in which the conductive member 20 is provided with the body portion 60, one end of the convex portion 50 in the extending direction thereof can be connected with the outer circumferential surface of the body portion 60, and the convex portion 50 extends from the outer circumferential surface of the body portion 60 to the outer circumferential surface of the conductive member 20. Of course, the convex portion 50 and the body portion 60 can also have no connection relationship, and the convex portion 50 can be arranged in a spaced manner with the outer circumferential surface of the body portion 60.

[0084] ​The protrusions 50 are arranged on the surface of the conductive member 20 facing the first wall 11, so that the protrusions 50 are more convenient to manufacture, because the conductive member 20 is separately formed and has flexible size, relatively high structure, and simple structure, and the processing convenience and processing cost of arranging the protrusions 50 on the surface of the conductive member 20 facing the first wall 11 are low, thereby reducing the overall cost of the overall electrochemical device 100.

[0085] In the embodiment in which the protrusions 50 are arranged on the conductive member 20, the protrusions 50 and the conductive member 20 can be separately arranged and then connected as a whole structure by welding, bonding or the like.

[0086] Of course, the conductive member 20 and the protrusions 50 can also be integrally formed. It can be understood that the conductive member 20 and the protrusions 50 are formed by an integral forming process, such as stamping, milling, casting or the like. The conductive member 20 and the protrusions 50 are integrally formed, which can realize the arrangement of the protrusions 50 on the conductive member 20 by a simple and convenient manufacturing method, and the overall structure formed by the conductive member 20 and the protrusions 50 has better strength.

[0087] In some embodiments, the electrochemical device 100 includes a plurality of protrusions 50, and the plurality of protrusions 50 are arranged at intervals around the first through hole 111.

[0088] Preferably, the plurality of protrusions 50 can be arranged at intervals around the first through hole 111, and the plurality of protrusions 50 are arranged at intervals, so that after the insulating member 40 is damaged, the plurality of protrusions 50 can jointly support the conductive member 20 and the first wall 11, and the conductive member 20 and the first wall 11 are uniformly stressed, thereby improving the stability of the channel, and the distribution of the channel formed is more uniform, and the safety of the pressure relief process is improved. Of course, the plurality of protrusions 50 can also be arranged at non-uniform intervals around the first through hole 111. Figure 11 In the embodiment shown in FIG. 2, the surface of the conductive member 20 facing the first wall 11 is provided with four protrusions 50, and the four protrusions 50 are arranged at intervals around the first through hole 111. Figure 12 In the embodiment shown in FIG. 3, the surface of the conductive member 20 facing the first wall 11 is provided with three protrusions 50, and the three protrusions 50 are arranged at intervals around the first through hole 111. Figure 13 In the embodiment shown in FIG. 4, the surface of the conductive member 20 facing the first wall 11 is provided with two protrusions 50, and in the direction perpendicular to the first direction X, the two protrusions 50 are arranged on opposite sides of the body portion 60.

[0089] The plurality of protrusions 50 are arranged at intervals around the first through hole 111, so that after the pressure inside the electrochemical device 100 reaches a threshold value, the plurality of protrusions 50 jointly damage the insulating member 40, and the plurality of protrusions 50 can jointly support the conductive member 20 and the first wall 11, so that the conductive member 20 and the first wall 11 are uniformly stressed, thereby improving the stability of the channel formed, and facilitating rapid and stable pressure relief.

[0090] To ensure that the insulation member 40 can be completely destroyed along the radial direction of the first through hole 111, a channel extending along the radial direction of the first through hole 111 is formed. Therefore, as shown in FIGS. 11A and 11B, in some embodiments, the protrusion 50 extends beyond the hole wall of the second through hole 41 at one end close to the first through hole 111, and the protrusion 50 extends beyond the outer edge of the insulation member 40 or is flush with the outer edge of the insulation member 40 at one end away from the first through hole 111. Figure 14 、 Figure 15 As shown in FIGS. 12A and 12B, in some embodiments, the protrusion 50 extends beyond the hole wall of the second through hole 41 at one end close to the first through hole 111, and the protrusion 50 extends beyond the outer edge of the insulation member 40 at one end away from the first through hole 111. Figure 14 As shown in FIGS. 13A and 13B, in some embodiments, the protrusion 50 extends beyond the hole wall of the second through hole 41 at one end close to the first through hole 111, and the protrusion 50 is flush with the outer edge of the insulation member 40 at one end away from the first through hole 111. Figure 15 As shown in FIGS. 13A and 13B, in some embodiments, the protrusion 50 extends beyond the hole wall of the second through hole 41 at one end close to the first through hole 111, and the protrusion 50 is flush with the outer edge of the insulation member 40 at one end away from the first through hole 111.

[0091] The protrusion 50 has two ends along its extension direction, one end is closer to the first through hole 111 in the radial direction of the first through hole 111 than the other end.

[0092] The protrusion 50 extends beyond the hole wall of the second through hole 41 at one end close to the first through hole 111, and the protrusion 50 extends beyond the outer edge of the insulation member 40 or is flush with the outer edge of the insulation member 40 at one end away from the first through hole 111, so that the protrusion 50 can form a channel along the radial direction of the first through hole 111 after destroying the insulation member 40 to communicate the inside and outside of the housing 10, which is conducive to faster and smoother pressure relief and reduces the risk of safety accidents caused by thermal runaway of the electrochemical device 100.

[0093] In other embodiments, the one end of the protrusion 50 away from the first through hole 111 can also be covered by the insulation member 40, that is, the outer edge of the insulation member 40 extends beyond the one end of the protrusion 50 away from the first through hole 111 (as shown in FIGS. 14A and 14B). Figure 17 、 Figure 18 As shown in FIGS. 15A and 15B, in some embodiments, the protrusion 50 extends beyond the hole wall of the second through hole 41 at one end close to the first through hole 111, and the protrusion 50 is flush with the outer edge of the insulation member 40 at one end away from the first through hole 111.

[0094] There are various ways for the protrusion 50 to destroy the insulation member 40, for example, the first wall 11 or the conductive member 20 is stressed so that the first wall 11 and the conductive member 20 move towards each other, and in the process of the first wall 11 and the conductive member 20 moving closer to each other, the protrusion 50 extrudes the insulation member 40 until the protrusion 50 breaks the insulation member 40 in the first direction X, the protrusion 50 can be supported between the first wall 11 and the conductive member 20, and the insulation member 40 is formed as a discontinuous structure in the circumferential direction of the first through hole 111, and the protrusion 50 can keep the insulation member 40 in a discontinuous state in the circumferential direction of the first through hole 111. Along the circumferential direction of the first through hole 111, the gap between the protrusion 50 and the insulation member 40 is the channel, and the gas in the electrochemical device 100 can be discharged from the gap between the protrusion 50 and the insulation member 40 in the circumferential direction of the first through hole 111. In this embodiment, the protrusion 50 can be made of an insulating material or an electrically conductive material.

[0095] In other embodiments, the electrode assembly 30 includes a first tab 31 and a second tab 32 of opposite polarity, the first tab 31 being electrically connected to the conductive element 20 and the second tab 32 being electrically connected to the housing 10; the protrusion 50 is configured to form a channel between the conductive element 20 and the first wall 11 communicating between the interior and exterior of the housing 10 after the insulating element 40 is melted.

[0096] The first tab 31 and the second tab 32 are the positive and negative tabs, respectively. The protrusion 50 can be made of conductive material.

[0097] When the first wall 11 or the conductive element 20 is subjected to force, the first wall 11 and the conductive element 20 move towards each other. During the process of the first wall 11 and the conductive element 20 approaching each other, the protrusion 50 squeezes the insulating element 40 until the protrusion 50 crushes the insulating element 40 in the first direction X. The protrusion 50 can support between the first wall 11 and the conductive element 20, and then the conductive element 20 and the first wall 11 are electrically connected through the protrusion 50, that is, the positive and negative electrodes of the electrochemical device 100 are electrically connected, and the electrochemical device 100 is short-circuited. After the short circuit, the temperature of the electrochemical device 100 rises rapidly, and the high temperature causes the insulating element 40 to melt. The molten insulating element 40 has fluidity, and the molten insulating element 40 flows non-directionally to form a channel between the first wall 11 and the conductive element 20, or the molten insulating element 40 is squeezed to the outside of the outer shell 10 by the internal pressure of the electrochemical device 100 and forms a channel between the first wall 11 and the conductive element 20. For example, as Figure 6 As shown, the conductive element 20 is located inside the outer casing 10. The conductive element 20 covers the first through hole 111 from the side of the first wall 11 facing the electrode assembly 30, which can reduce the overall structure of the electrochemical device 100. The internal pressure of the electrochemical device 100 will drive the conductive element 20 to move closer to the first wall 11 from the side of the conductive element 20 away from the insulating element 40. Then the protrusion 50 will squeeze the insulating element 40 until the protrusion 50 crushes the insulating element 40. The outer casing 10 and the conductive element 20 are electrically connected through the protrusion 50, and the electrochemical device 100 is short-circuited. The protrusion 50 is supported between the first wall 11 and the conductive element 20 to prevent the conductive element 20 from moving further closer to the first wall 11. Then the gas pressure inside the electrochemical device 100 can squeeze the molten insulating element 40 from between the first wall 11 and the conductive element 20 to the second through hole 41. The first through hole 111 finally discharges to the outside of the outer casing 10. Figure 6 The hollow arrow in the image can point in either the direction in which the molten insulating part 40 is extruded or the direction in which the internal pressure of the electrochemical device 100 is released.

[0098] The first lug 31 is electrically connected with the conductive member 20, and the second lug 32 is electrically connected with the shell 10, so that the conductive member 20 and the shell 10 form two poles of the electrochemical device 100 with opposite polarity. When the pressure inside the electrochemical device 100 increases to a threshold value, the convex part 50 breaks the insulating member 40, the electrochemical device 100 is short-circuited, the temperature of the electrochemical device 100 after short-circuiting rises rapidly, the high temperature causes the insulating member 40 to melt, and the locally melted insulating member 40 flows to both sides of the convex part 50 under the action of the gas inside the shell 10, forming a channel with a larger cross section for pressure relief, thereby improving the pressure relief efficiency of the electrochemical device 100 when thermal runaway occurs. At the same time, the top of the convex part 50 (if the convex part 50 is arranged on the conductive member 20, the top of the convex part 50 refers to the end of the convex part 50 away from the conductive member 20, if the convex part 50 is arranged on the first wall 11, the top of the convex part 50 refers to the end of the convex part 50 away from the first wall 11) must be uneven microscopically. As long as the higher part of the top of the convex part 50 is in contact with the shell, local short-circuiting and heat release can occur, and then the melting of the insulating member 40 around the convex part 50 can be realized before the entire insulating member 40 is completely destroyed by the convex part 50, thereby accelerating the formation of the pressure relief channel, improving the reaction sensitivity of the electrochemical device 100 to abnormal increase of internal pressure, reducing the risk of safety accidents caused by thermal runaway of the electrochemical device 100, and improving the safety performance of the electrochemical device 100. According to different battery design requirements, the melting of the insulating member 40 around the convex part 50 caused by local short-circuiting can be the main effect of forming a pressure relief channel. For example, when the insulating member 40 is made of a material with high tear resistance and / or the top of the convex part 50 is not sharp, the pressure required to break the insulating member 40 by the convex part 50 is too large to ensure safety. At this time, the local short-circuiting and heat release caused by the local short-circuiting of the conductive member 20 and the shell 10 by the convex part 50 can form a pressure relief channel for the electrochemical device 100 under low internal pressure, thereby achieving safe pressure relief.

[0099] Moreover, the local short-circuiting and heat release caused by the local short-circuiting of the first wall 11 and the conductive member 20 by the convex part 50 not only greatly improves the pressure relief sensitivity of the electrochemical device 100 to abnormal increase of internal pressure and improves safety, but also, when the end of the convex part 50 away from the first through hole 111 does not exceed the outer edge of the insulating member 40 or is flush with the outer edge of the insulating member 40 (as shown in Figure 6 the drawings), the local short-circuiting and heat release cause the insulating member 40 not cut off by the convex part 50 to melt rapidly and form a pressure relief channel rapidly, thereby reducing the difficulty of controlling the size of the insulating member 40 and the conductive member 20 and reducing production costs.

[0100] As shown in Figure 16 , Figure 17As shown, in some embodiments, the protrusion 50 forms a groove 42 on the surface of the insulating member 40 along the first direction X to form a weak portion 43; the protrusion 50 is inserted into the groove 42 and abuts against the weak portion 43, and the protrusion 50 is configured to break the weak portion 43 when the internal pressure of the housing 10 reaches a threshold to form a pressure relief channel or to short-circuit the conductive member 20 with the housing 10.

[0101] The weak point 43 is a position on the insulating member 40 with a smaller thickness and opposite to the protrusion 50. The weak point 43 can be formed by providing a groove 42 on the insulating member 40. The groove 42 can be formed before the insulating member 40 is assembled between the first wall 11 and the conductive member 20. The groove 42 is formed on the surface of the insulating member 40 facing the protrusion 50 using a grooving-related process to reduce the thickness of the insulating member 40 at the position corresponding to the groove 42. In this embodiment, the thickness of the insulating member 40 at the position corresponding to the groove 42 is less than the thickness of the insulating member 40 at other positions. After the insulating member 40 is assembled between the first wall 11 and the conductive member 20, the protrusion 50 is inserted into the groove 42. The protrusion 50 and the groove 42 are provided in a one-to-one correspondence. The groove 42 can be a triangular groove 42, a rectangular groove 42, etc.

[0102] In one embodiment where the protrusion 50 is provided only on the surface of the conductive member 20 facing the first wall 11, the groove 42 may be provided only on the surface of the insulating member 40 facing the conductive member 20.

[0103] In embodiments where the protrusion 50 is provided only on the surface of the first wall 11 facing the conductive member 20, the groove 42 may be provided only on the surface of the insulating member 40 facing the first wall 11.

[0104] In embodiments where both the surface of the conductive member 20 facing the first wall 11 and the surface of the first wall 11 facing the conductive member 20 have protrusions 50, grooves 42 can be provided on both the surface of the insulating member 40 facing the conductive member 20 and the surface facing the first wall 11. In embodiments where both the surface of the conductive member 20 facing the first wall 11 and the surface of the first wall 11 facing the conductive member 20 have protrusions 50, along the first direction X, the projections of the protrusions 50 on the conductive member 20 and the protrusions 50 on the first wall 11 onto the insulating member 40 can coincide, and therefore the grooves 42 provided on both sides of the insulating member 40 can also coincide. In embodiments where both the surface of the conductive member 20 facing the first wall 11 and the surface of the first wall 11 facing the conductive member 20 have protrusions 50, along the first direction X, the projections of the protrusions 50 on the conductive member 20 and the protrusions 50 on the first wall 11 onto the insulating member 40 can be completely offset, i.e., not coincident, and therefore the grooves 42 provided on both sides of the insulating member 40 can also be offset.

[0105] The recess 42 can be formed after the insulating piece 40 is assembled between the first wall 11 and the conductive piece 20, due to the extrusion of the insulating piece 40 by the first wall 11 and the conductive piece 20, and the protrusion 50 is embedded into the insulating piece 40.

[0106] The weak portion 43 is arranged to make the insulating piece 40 more easily broken by the protrusion 50, so that the short circuit of the electrochemical device 100 can be achieved in time, thereby achieving pressure relief in time.

[0107] After the protrusion 50 breaks the insulating piece 40, the protrusion 50 is supported between the conductive piece 20 and the first wall 11, the conductive piece 20 is short-circuited with the shell 10 through the protrusion 50, the temperature of the electrochemical device 100 rises rapidly, the high temperature makes the insulating piece 40 melt, so that the protrusion supported between the conductive piece 20 and the first wall 11 can form a channel connecting the inside and the outside of the shell 10 or the protrusion 50 allows the melted insulating piece 40 to be extruded from between the conductive piece 20 and the first wall 11 by the gas inside the electrochemical device 100, thereby forming a channel between the conductive piece 20 and the first wall 11, and relieving pressure through the channel, reducing the risk of safety accidents caused by thermal runaway of the electrochemical device 100, and improving the safety performance of the electrochemical device 100.

[0108] The protrusion 50 breaks the weak portion 43 when the pressure inside the shell 10 reaches a threshold value to achieve the short circuit of the conductive piece 20 and the shell 10 through the protrusion 50, thereby achieving pressure relief of the electrochemical device 100, which can relieve pressure when the electrochemical device 100 is in thermal runaway without the need to set a pressure relief mechanism on the shell 10, and can not damage the integrity of the structure of the shell 10, thereby ensuring the structural strength of the shell 10.

[0109] As shown in FIG. 1, the thickness of the weak portion 43 can be set according to actual needs. In some embodiments, the thickness of the weak portion 43 is D, which satisfies 0.01 mm≤D≤0.50 mm. Figure 18 The thickness of the weak portion 43 refers to the size of the weak portion 43 in the first direction X. For example, D can be 0.02 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm, etc.

[0110]

[0111] ​If the thickness D of the weak portion 43 is too small, for example, less than 0.01 mm, the weak portion 43 is easily damaged by the protrusion 50 or the protrusion 50 easily causes a local short circuit between the conductive member 20 and the shell 10, the electrochemical device 100 is too sensitive to internal pressure changes, causing performance waste; if the thickness D of the weak portion 43 is too large, for example, greater than 0.50 mm, that is, the insulating member 40 between the top of the protrusion 50 and the first wall 11 of the shell 10 of the electrochemical device 100 is too thick under normal conditions, the protrusion 50 can completely damage the insulating member 40 or achieve a local short circuit only under a large pressure, making the pressure threshold too high, which is not conducive to ensuring the safety of the electrochemical device 100. The thickness D of the weak portion 43 satisfies 0.01 mm≤D≤0.50 mm, so that the weak portion 43 can have good insulation performance and be relatively easy to be crushed by the protrusion 50, so as to ensure timely pressure relief when the internal pressure of the electrochemical device 100 is too large.

[0112] In some embodiments, the protrusion 50 extends in a straight line or a curve on the surface of the first wall 11 facing the conductive member 20, that is, the protrusion 50 arranged on the surface of the first wall 11 facing the conductive member 20 can extend in a straight line or a curve. In some embodiments, the protrusion 50 extends in a straight line or a curve in the surface of the conductive member 20 facing the first wall 11, that is, the protrusion 50 arranged on the surface of the conductive member 20 facing the first wall 11 can extend in a straight line or a curve.

[0113] For example, the protrusion 50 extends in a straight line along the radial direction of the first through hole 111, and for another example, the protrusion 50 extends along an S-shaped path.

[0114] The cross section of the protrusion 50 refers to the cross section of the protrusion 50 at any position in the extension direction thereof, for example, Figure 17 As shown in the figure, in the present embodiment, the cross section of the protrusion 50 is triangular. The cross section of the protrusion 50 is triangular, so that the top of the protrusion 50 is more sharp and can be more easily crushed to damage the insulating member 40.

[0115] In other embodiments, the cross section of the protrusion 50 can also be rectangular, semicircular, semi-elliptical, etc.

[0116] Please continue to refer to Figure 17 In some embodiments, the height of the triangular cross section of the protrusion 50 is H, and the width of the triangular cross section of the protrusion 50 is L, which satisfies 1 / 5≤H / L≤3.

[0117] The height of the protrusion 50 refers to the dimension of the protrusion 50 in the first direction X. For example, the protrusion 50 is arranged on the surface of the conductive member 20 facing the first wall 11, and the height of the protrusion 50 refers to the dimension of the protrusion 50 protruding from the surface of the conductive member 20 facing the first wall 11 in the first direction X.

[0118] The width of the protrusion 50 refers to the dimension of the cross section of the protrusion 50 in the direction perpendicular to the first direction X.

[0119] H / L can be 2 / 5, 4 / 5, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.7, etc.

[0120] In the embodiment in which the cross section of the protrusion 50 is triangular, the larger H / L is, the sharper the edge of the protrusion 50 facing the first wall 11 is, and the more conducive to breaking the insulating member 40.

[0121] If H / L is too small, for example, less than 1 / 5, in the case of the cross section of the protrusion 50 being triangular, the triangle is too flat as a whole and has low sharpness, making it difficult to pierce the insulating member 40 and thus difficult to form a smooth pressure relief channel; if H / L is too large, for example, greater than 3, the cross section of the protrusion is too sharp and can pierce the insulating member 40 under low pressure, and due to the sharp end discharge effect, the protrusion 50 is also more likely to cause a local short circuit between the conductive member 20 and the first wall 11, causing the electrochemical device 100 to relieve pressure under low internal pressure, resulting in performance waste.

[0122] Therefore, 1 / 5≤H / L≤3, so that after the protrusion 50 breaks the insulating member 40, the channel formed between the first wall 11 and the conductive member 20 by the protrusion 50 can meet the pressure relief needs of the electrochemical device 100, so that the electrochemical device 100 can relieve pressure in time and quickly, reducing the risk of safety accidents caused by thermal runaway of the electrochemical device 100.

[0123] For reference Figure 18 , Figure 19 and Figure 20 In some embodiments, the height of the protrusion 50 is H, and the thickness of the insulating member 40 is K, satisfying 0.01mm≤H<K.

[0124] The thickness of the insulating member 40 is the dimension of the insulating member 40 in the first direction X. In the embodiment in which the insulating member 40 forms a groove 42, the thickness K of the insulating member 40 refers to the thickness of the region of the insulating member 40 other than the position corresponding to the groove 42. The height H of the protrusion 50 is less than the thickness K of the insulating member 40, ensuring that the insulating member 40 can play an insulating role at the position corresponding to the protrusion 50 before the first wall 11 or the conductive member 20 is subjected to an external force.

[0125] The height H of the protrusion 50 can be 0.02mm, 0.05mm, 0.07mm, 0.10mm, 0.15mm, 0.17mm, 0.20mm, 0.25mm, 0.27mm, etc.

[0126] The height H of the convex part 50 and the thickness K of the insulating part 40 satisfy 0.01mm≤H<K, so that the insulating part 40 has good insulation performance, and after the convex part 50 breaks the insulating part 40, the convex part 50 can support the first wall 11 and the conductive part 20 in the first direction X, so that a channel with a large cross-sectional area for pressure relief is formed between the first wall 11 and the conductive part 20 to meet the pressure relief requirement.

[0127] The embodiments of the present application also provide a power-using equipment, which comprises the electrochemical device 100 provided by any of the above embodiments. The electrochemical device 100 is used as an energy supply component of the power-using equipment to execute the function of the power-using equipment.

[0128] The power-using equipment can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric drill, an electric saw, an electric vehicle, an electric motorcycle, an electric bicycle, etc.

[0129] The electrochemical device 100 provided by any of the above embodiments has good safety, which can improve the power-using safety of the power-using equipment provided with the electrochemical device 100.

[0130] The above merely provides the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electrochemical device, characterized in that, include: The outer casing has a first wall, and the first wall has a first through hole; A conductive element that covers the first through hole; An electrode assembly is housed within the housing, and the conductive element is electrically connected to the electrode assembly to bring out one polarity of the electrode assembly; as well as An insulating element is disposed between the conductive element and the first wall to insulate and isolate the conductive element and the housing. The insulating element has a second through hole. Along a first direction, at least a portion of the projection of the conductive element is located in both the first through hole and the second through hole. The first direction is the thickness direction of the first wall. Wherein, the surface of the first wall facing the conductive element and / or the surface of the conductive element facing the first wall are provided with protrusions; The end of the protrusion near the first through hole extends beyond the wall of the second through hole. Along the first direction, the protrusion overlaps with the insulating member. The protrusion is configured to destroy the insulating member that serves as an insulating seal between the conductive member and the first wall when the internal pressure of the electrochemical device reaches a threshold, and to electrically connect the first wall and the conductive member, so that a channel connecting the interior and exterior of the housing is formed between the conductive member and the first wall.

2. The electrochemical device according to claim 1, characterized in that, The protrusion is disposed on the surface of the conductive element facing the first wall.

3. The electrochemical device according to claim 2, characterized in that, The conductive element is integrally formed with the protrusion.

4. The electrochemical device according to claim 1, characterized in that, The electrochemical device includes a plurality of protrusions, which are arranged at intervals around the first through hole.

5. The electrochemical device according to claim 1, characterized in that, The end of the protrusion away from the first through hole extends beyond the outer edge of the insulating member or is flush with the outer edge of the insulating member.

6. The electrochemical device according to any one of claims 1-5, characterized in that, The electrode assembly includes a first electrode and a second electrode with opposite polarities. The first electrode is electrically connected to the conductive element, and the second electrode is electrically connected to the outer casing. The protrusion is configured to form a channel between the conductive element and the first wall, connecting the interior and exterior of the housing, after the insulating element is melted.

7. The electrochemical device according to claim 6, characterized in that, The protrusion has a groove formed on the surface of the insulating member along the first direction to form a weak part; The protrusion is inserted into the groove and abuts against the weak portion. The protrusion is configured to break the weak portion when the internal pressure of the housing reaches a threshold, so as to short-circuit the conductive element with the housing.

8. The electrochemical device according to claim 7, characterized in that, The thickness of the weak part is D, which satisfies 0.01mm≤D≤0.5mm.

9. The electrochemical device according to claim 1, characterized in that, The protrusion extends along a straight line or curve on the surface of the first wall facing the conductive element and / or the surface of the conductive element facing the first wall, and the cross-section of the protrusion is triangular.

10. The electrochemical device according to claim 9, characterized in that, The height of the cross-section of the protrusion is H, and the width of the cross-section of the protrusion is L, satisfying 1 / 5 ≤ H / L ≤ 3.

11. The electrochemical device according to claim 1, characterized in that, The height of the protrusion is H, and the thickness of the insulating component is K, satisfying 0.01mm≤H<K.

12. An electrical appliance, characterized in that, Includes the electrochemical device according to any one of claims 1-11.

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