Secondary battery and preparation method thereof

Abstract

The embodiments of the present disclosure relate to the field of energy storage and provide a secondary battery and a preparation method thereof, the secondary battery comprising: a lower plastic and a substrate arranged along a stack; positive and negative electrode columns arranged at intervals, the positive and negative electrode columns respectively and sequentially passing through the lower plastic and the substrate along a first direction, the positive electrode column comprising a bottom plate abutting against a side of the lower plastic away from the substrate, and a main body passing through the lower plastic and the substrate; a positive electrode upper plastic sleeved on one end of the positive electrode column, and a negative electrode upper plastic sleeved on one end of the negative electrode column, the positive and negative electrode upper plastics being made of the same insulating material; a positive electrode sealing ring located between the positive electrode column and the lower plastic; a conductive material being doped in a portion of the lower plastic abutting against the bottom plate; or, the secondary battery further comprising: a conductive structure embedded in an end portion of at least one of the lower plastic, the positive electrode upper plastic and the positive electrode sealing ring, different regions of the conductive structure being in ohmic contact with the substrate and the positive electrode column, respectively, which is at least conducive to achieving ohmic contact between the positive electrode column and the substrate and improving the safety of the secondary battery.

Description

Technical Field

[0001] The present disclosure relates to the field of energy storage, and in particular to a secondary battery and a preparation method thereof. Background Art

[0002] Currently, in the energy storage field, to ensure the safety of secondary batteries during use, the battery cells are typically assembled in a hard shell, and the hard shell that houses the battery cells is generally made of metal. To prevent the phenomenon of a sharp increase in the loop current formed by the secondary battery, as well as to avoid problems such as corrosion of the battery cell shell and lithium deposition, it is necessary to connect the substrate and the positive electrode of the secondary battery to make the substrate positively charged to solve the shell corrosion problem. However, if metal is used to directly connect the substrate and the positive electrode of the secondary battery, since the resistance of metal is generally in the milliohm level, when the secondary battery shorts, the loop current will increase sharply, which can easily lead to ignition and other safety hazards such as fire.

[0003] However, to address the issues of shell corrosion and excessive loop current in secondary batteries, the plastic on the positive electrode is usually designed to have a certain degree of conductivity. This not only prevents the simultaneous preparation of the plastic on the positive electrode and the plastic on the negative electrode, but also reduces the service life and safety of the plastic on the positive electrode, affecting the safety of the secondary battery in the middle and later stages. Summary of the Invention

[0004] The embodiments of the present disclosure provide a secondary battery and a method for preparing the same, which can at least facilitate achieving ohmic contact between a positive electrode column and a substrate, and improve the safety of the secondary battery.

[0005] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a secondary battery, comprising: a lower plastic and a substrate stacked along a first direction; a positive electrode column and a negative electrode column spaced apart along a second direction, the positive electrode column and the negative electrode column respectively passing through the lower plastic and the substrate in sequence along the first direction, and the positive electrode column comprises a bottom plate abutting against a side of the lower plastic away from the substrate, and a main body located on the bottom plate, the main body passing through the lower plastic and the substrate; a positive electrode upper plastic sleeved on one end of the positive electrode column, and a negative electrode upper plastic sleeved on one end of the negative electrode column, the positive electrode upper plastic and the negative electrode upper plastic The plastic is made of the same insulating material, and along the second direction, the positive electrode upper plastic is also located between the positive electrode column and the substrate; the positive electrode sealing ring is located between the positive electrode column and the lower plastic along the second direction; wherein, the partial area where the lower plastic abuts the bottom plate is doped with conductive material to achieve ohmic contact between the partial area of ​​the lower plastic and the substrate and the bottom plate; or, the secondary battery further includes: a conductive structure embedded in the end of at least one of the lower plastic, the positive electrode upper plastic and the positive electrode sealing ring, and different areas of the conductive structure are in ohmic contact with the substrate and the positive electrode column respectively.

[0006] In some embodiments, the lower plastic has a first receiving hole for leading out the positive electrode column, and the conductive structure is not only located on the sidewalls of the lower plastic used to enclose the first receiving hole, but also on two opposite sides of the lower plastic along the first direction.

[0007] In some embodiments, the positive electrode plastic has an extension portion located between the positive electrode column and the substrate, and the conductive structure is located not only on the bottom surface of the extension portion facing the bottom plate, but also on the outer wall and inner wall opposite to each other along the second direction.

[0008] In some embodiments, the positive electrode sealing ring has a first end facing the lower plastic, and the conductive structure is located not only on the side wall of the first end facing the lower plastic, but also on two opposite sides of the first end along the first direction; or, the positive electrode sealing ring has a second end facing the positive electrode upper plastic, and the conductive structure is located not only on the top surface of the second end facing the positive electrode upper plastic, but also on the opposite outer and inner sides of the second end along the second direction.

[0009] In some embodiments, the resistance range of the conductive structure is 100Ω~10000Ω; and / or the material of the conductive structure includes a conductive polymer material or a conductive ceramic material.

[0010] In some embodiments, the conductive material includes at least one of carbon black, carbon nanotubes, graphene, metal, and metal oxide.

[0011] In some embodiments, the lower plastic includes a first portion and a second portion spaced apart along the second direction, the first portion has a first accommodating hole for leading out the positive electrode column, the second portion has a second accommodating hole for leading out the negative electrode column, and the first portion is doped with the conductive material.

[0012] In some embodiments, a ratio of the volume of the conductive structure to the volume of the substrate is less than or equal to 3%.

[0013] In some embodiments, at a test voltage of 500V, the resistance of the plastic on the positive electrode and the plastic on the negative electrode are both greater than 9MΩ.

[0014] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a method for preparing a secondary battery, comprising: providing a lower plastic, a substrate, a positive electrode column, a negative electrode column and a positive electrode sealing ring, wherein the lower plastic has a first accommodating hole for leading out the positive electrode column and a first accommodating hole for leading out the negative electrode column, and the substrate has a second accommodating hole for leading out the positive electrode column and a second accommodating hole for leading out the negative electrode column; doping a conductive material in a partial area where the lower plastic abuts the positive electrode column to achieve ohmic contact between a partial area of ​​the lower plastic and the substrate and the positive electrode column; or forming a conductive structure, and embedding the conductive structure into an end portion of at least one of the lower plastic, the positive electrode upper plastic and the positive electrode sealing ring, and different areas of the conductive structure are divided into respectively making ohmic contact with the substrate and the positive electrode column; stacking the lower plastic and the substrate along the first direction; placing a positive electrode sealing ring in the first accommodating hole, and passing the positive electrode column through the first accommodating hole and the second accommodating hole in sequence along the first direction, so that the positive electrode sealing ring is located between the positive electrode column and the lower plastic along the second direction; passing the negative electrode column through the first accommodating hole and the second accommodating hole in sequence along the first direction; using the same insulating material to form the positive electrode upper plastic and the negative electrode upper plastic, the positive electrode upper plastic is sleeved on one end of the positive electrode column, the negative electrode upper plastic is sleeved on one end of the negative electrode column, and along the second direction, the positive electrode upper plastic is also located between the positive electrode column and the substrate.

[0015] In some embodiments, the lower plastic has a first accommodating hole for leading out the positive electrode column, the positive electrode sealing ring has a first end facing the lower plastic, and the positive electrode sealing ring has a second end facing the positive electrode upper plastic; the step of embedding the conductive structure into the end of at least one of the lower plastic or the positive electrode sealing ring includes: providing a conductive structure; installing the conductive structure on the side wall of the lower plastic for enclosing the first accommodating hole and the two opposite sides of the lower plastic along the first direction; or, installing the conductive structure on the side wall of the first end facing the lower plastic and the two opposite sides of the first end along the first direction; or, installing the conductive structure on the top surface of the positive electrode upper plastic at the second end and the outer and inner sides of the second end facing the second direction.

[0016] In some embodiments, the plastic on the positive electrode has an extension portion located between the positive electrode column and the substrate. After the positive electrode column is passed through the first accommodating hole and the second accommodating hole in sequence along the first direction, and before the plastic on the positive electrode is formed, there is a gap between the positive electrode column and the substrate; the step of forming the conductive structure includes: forming the conductive structure covering the gap, and the conductive structure forms a groove; the step of forming the plastic on the positive electrode: forming the plastic on the positive electrode to fill the groove.

[0017] The technical solution provided by the embodiments of the present disclosure has at least the following advantages:

[0018] Changing the material composition of the area where the lower plastic contacts the bottom plate of the substrate reduces the electrical resistance of the area where the lower plastic contacts the bottom plate. This helps achieve ohmic contact between the substrate and the positive electrode without adding additional components to the secondary battery, or changing the structure of the battery cell. This helps to simplify the secondary battery manufacturing process and production costs. Alternatively, a conductive structure can be provided within the secondary battery, embedded in the end of at least one of the lower plastic, the positive electrode upper plastic, and the positive electrode sealing ring, without affecting the secondary battery's appearance. Moreover, in the above two design concepts, the plastic on the positive electrode and the plastic on the negative electrode are both made of the same insulating material. On the one hand, it is conducive to ensuring that the plastic on the positive electrode and the plastic on the negative electrode have good insulation properties, high temperature resistance and long service life, thereby helping to reduce the probability of the plastic on the positive electrode and the plastic on the negative electrode being deformed after being subjected to force or heat, and it is also conducive to reducing the probability of the secondary battery being broken down by high voltage in the middle and late stages of use, resulting in battery cell failure, thereby improving the safety and service life of the secondary battery; on the other hand, the plastic on the positive electrode and the plastic on the negative electrode are both made of the same insulating material, then the plastic on the positive electrode and the plastic on the negative electrode can be formed simultaneously, which is conducive to simplifying the manufacturing process of the secondary battery and reducing factors affecting the yield of the secondary battery. In addition, whether it is by using the lower plastic doped with conductive material in the partial area abutting the bottom plate to achieve ohmic contact between the substrate and the positive electrode column, or by using the conductive structure embedded in the end of at least one of the lower plastic, the positive electrode upper plastic and the positive electrode sealing ring to achieve slight conduction between the substrate and the positive electrode column, it is beneficial to make the substrate slightly positively charged when the secondary battery is in the working state, thereby avoiding corrosion of the battery cell casing or lithium deposition, and also helping to avoid excessive loop current when the secondary battery is short-circuited, so as to further reduce the probability of secondary battery fire, thereby improving the safety of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of a first partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure;

[0021] Figure 2 A schematic diagram of a second partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure;

[0022] Figure 3 A third partial cross-sectional structural diagram of a secondary battery provided in one embodiment of the present disclosure;

[0023] Figure 4 A schematic diagram of a fourth partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure;

[0024] Figure 5 A fifth partial cross-sectional structural diagram of a secondary battery provided in one embodiment of the present disclosure;

[0025] Figure 6 A sixth partial cross-sectional structural diagram of a secondary battery provided in one embodiment of the present disclosure;

[0026] Figure 7 A schematic diagram of a partial cross-sectional structure of a substrate and lower plastic in a secondary battery provided by an embodiment of the present disclosure;

[0027] Figure 8 This is a schematic diagram of a seventh partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] As can be seen from the background technology, the safety of secondary batteries needs to be further improved.

[0029] After analysis, it was found that in order to make the plastic on the positive electrode have a certain conductivity, it is necessary to change the material composition of the plastic on the positive electrode. For example, carbon nanotubes can be added to the insulating material to reduce the resistance of the plastic on the positive electrode and reduce the insulation performance of the plastic on the positive electrode.

[0030] In this way, firstly, changing the material composition of the plastic on the positive electrode will also lead to a decrease in the high-temperature performance of the plastic on the positive electrode. As a result, in certain safety experiments, such as short circuit or thermal runaway, the plastic on the positive electrode is more likely to be dissolved, deformed and destroyed by high temperature, thereby reducing the safety of the secondary battery; secondly, changing the material composition of the plastic on the positive electrode will easily lead to a decrease in the insulation and storage performance of the plastic on the positive electrode. In the current energy storage field, there is a demand for high voltage and long life. Second, the secondary battery is very likely to be broken down by high voltage in the middle and late stages of use, resulting in battery cell failure; thirdly, changing the material composition of the plastic on the positive electrode makes it impossible to prepare the plastic on the positive electrode and the plastic on the negative electrode simultaneously, increasing the assembly complexity of the secondary battery. For injection-molded plastics, when the plastic on the positive electrode and the plastic on the negative electrode are made of different materials, different processes are required to be used to process them to form the plastic on the positive electrode and the plastic on the negative electrode, thereby increasing the production cost of the secondary battery and making the yield of the secondary battery affected by more factors.

[0031] The present disclosure provides a secondary battery and a method for manufacturing the same. In the secondary battery, the material composition of the area where the lower plastic contacts the base plate is changed to reduce the electrical resistance of the area where the lower plastic contacts the base plate. This facilitates achieving ohmic contact between the base plate and the positive electrode without adding additional components to the secondary battery, that is, without affecting the structural changes of the battery cell. This helps to minimize the manufacturing process and production costs of the secondary battery. Alternatively, a conductive structure is provided within the secondary battery, embedded in the end of at least one of the lower plastic, the positive electrode upper plastic, and the positive electrode sealing ring, without affecting the appearance of the secondary battery. Moreover, in the above two design concepts, the plastic on the positive electrode and the plastic on the negative electrode are both made of the same insulating material. On the one hand, it is conducive to ensuring that the plastic on the positive electrode and the plastic on the negative electrode have good insulation properties, high temperature resistance and long service life, thereby helping to reduce the probability of the plastic on the positive electrode and the plastic on the negative electrode being deformed after being subjected to force or heat, and it is also conducive to reducing the probability of the secondary battery being broken down by high voltage in the middle and late stages of use, resulting in battery cell failure, thereby improving the safety and service life of the secondary battery; on the other hand, the plastic on the positive electrode and the plastic on the negative electrode are both made of the same insulating material, then the plastic on the positive electrode and the plastic on the negative electrode can be formed simultaneously, which is conducive to simplifying the manufacturing process of the secondary battery and reducing factors affecting the yield of the secondary battery. In addition, whether it is by using the lower plastic doped with conductive material in the partial area abutting the bottom plate to achieve ohmic contact between the substrate and the positive electrode column, or by using the conductive structure embedded in the end of at least one of the lower plastic, the positive electrode upper plastic and the positive electrode sealing ring to achieve slight conduction between the substrate and the positive electrode column, it is beneficial to make the substrate slightly positively charged when the secondary battery is in the working state, thereby avoiding corrosion of the battery cell casing or lithium deposition, and also helping to avoid excessive loop current when the secondary battery is short-circuited, so as to further reduce the probability of secondary battery fire, thereby improving the safety of the secondary battery.

[0032] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0033] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0034] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0035] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0036] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0037] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and they can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0038] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​layers are exaggerated for better understanding and ease of description. When a component (such as a layer, film, region, or substrate) is described as being on or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. Conversely, when a component is described as being on the surface of another component, or as being formed or disposed on the surface of one component, it indicates that there is no third component between the two components. Furthermore, when a component is described as being "substantially" formed on another component, this means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0039] In the description of the embodiments of the present disclosure, when a component is referred to as "including" another component, unless otherwise specified, this does not exclude other components, and other components may further be included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them) or another component may be present between them. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "directly on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, this means that no other components are located between them.

[0040] The terms used herein in the description of the various embodiments are intended only to describe the specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is intended to include the plural form unless the context clearly indicates otherwise. A component includes a layer, film, region, or plate.

[0041] The following describes various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present disclosure to help readers better understand the embodiments of the present disclosure. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can be implemented.

[0042] An embodiment of the present disclosure provides a secondary battery, which will be described in detail below with reference to the accompanying drawings.

[0043] refer to Figures 1 to 6Any one of the secondary batteries includes: a lower plastic 100 and a substrate 101 stacked along a first direction X; a positive electrode column 102 and a negative electrode column 103 spaced apart along a second direction Y, the positive electrode column 102 and the negative electrode column 103 respectively passing through the lower plastic 100 and the substrate 101 in sequence along the first direction X, and the positive electrode column 102 includes a bottom plate 112 abutting against a side of the lower plastic 100 away from the substrate 101, and a main body 122 located on the bottom plate 112, the main body 122 22 penetrates the lower plastic 100 and the substrate 101; the positive upper plastic 104 is sleeved on one end of the positive electrode column 102, and the negative upper plastic 105 is sleeved on one end of the negative electrode column 103. The positive upper plastic 104 and the negative upper plastic 105 are made of the same insulating material. Along the second direction Y, the positive upper plastic 104 is also located between the positive electrode column 102 and the substrate 101; the positive sealing ring 106 is located between the positive electrode column 102 and the lower plastic 100 along the second direction Y.

[0044] Among them, reference Figure 1 or Figure 2 The portion of the lower plastic 100 that contacts the bottom plate 112 is doped with a conductive material to achieve ohmic contact between the portion of the lower plastic 100 and the substrate 101 and the bottom plate 112 .

[0045] Alternatively, refer to Figures 3 to 6 Any one of the secondary battery further includes: a conductive structure 107, embedded in the end of at least one of the lower plastic 100, the positive electrode upper plastic 104 and the positive electrode sealing ring 106, and different areas of the conductive structure 107 are in ohmic contact with the substrate 101 and the positive electrode column 102 respectively.

[0046] It should be noted that Figure 1 A schematic diagram of a first partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure; Figure 2 A schematic diagram of a second partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure; Figure 3 A third partial cross-sectional structural diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 4 A schematic diagram of a fourth partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure; Figure 5 A fifth partial cross-sectional structural diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 6 This is a schematic diagram of a sixth partial cross-sectional structure of a secondary battery provided in one embodiment of the present disclosure.

[0047] In addition, one, Figures 1 to 6In the figure, the bottom plate 112 in the positive electrode column 102 and the main body 122 for penetrating the lower plastic 100 and the substrate 101 are divided by dotted lines. The diameter of the bottom plate 112 is larger than the diameter of the main body 122. Secondly, in order to clearly illustrate the combination relationship between the positive electrode column 102 and other components in the secondary battery, as well as the combination relationship between the negative electrode column 103 and other components in the secondary battery, Figures 1 to 6 The lower plastic 100 and the substrate 101 are cut off along the second direction Y by double wavy lines; thirdly, compared with other components in the secondary battery, the size of the conductive structure 107 is relatively small. Figures 3 to 6 The conductive structure 107 is indicated by thicker black lines.

[0048] It is worth noting that, in order to achieve ohmic contact between the substrate 101 and the positive electrode column 102 , the secondary battery provided in one embodiment of the present disclosure includes at least the following two design concepts.

[0049] First, refer to 1 or Figure 2 By changing the material composition of the area where the lower plastic 100 contacts the bottom plate 112, the resistance of the area where the lower plastic 100 contacts the bottom plate 112 is reduced, while the other areas of the lower plastic 100 still have excellent insulation properties. This is beneficial for achieving ohmic contact between the substrate 101 and the positive electrode column 102 by modifying the area where the lower plastic 100 contacts the bottom plate 112 without adding any additional components to the secondary battery, thereby simplifying the manufacturing process and production cost of the secondary battery as much as possible.

[0050] Second, reference Figures 3 to 6 In any one of the embodiments, a conductive structure 107 is provided inside the secondary battery so that the conductive structure 107 is embedded in the end of at least one of the lower plastic 100, the positive electrode upper plastic 104 and the positive electrode sealing ring 106, without affecting the appearance of the secondary battery.

[0051] Moreover, in the above two design concepts, the plastic 104 on the positive electrode and the plastic 105 on the negative electrode are both made of insulating materials. On the one hand, it is beneficial to achieve ohmic contact between the substrate 101 and the positive electrode column 102 while ensuring that the plastic 104 on the positive electrode and the plastic 105 on the negative electrode have good insulation performance, high temperature resistance and long service life, avoiding the need to make a balanced choice between certain conductive properties, high temperature resistance and long service life in the material design of the plastic 104 on the positive electrode, thereby helping to reduce the probability of deformation of the plastic 104 on the positive electrode and the plastic 105 on the negative electrode after being subjected to force or heat, and further, helping to reduce the probability of the secondary battery being broken down by high voltage in the middle and late stages of use, resulting in cell failure, thereby improving the safety and service life of the secondary battery.

[0052] On the other hand, the positive electrode plastic 104 and the negative electrode plastic 105 are both made of the same insulating material, so the positive electrode plastic 104 and the negative electrode plastic 105 can be formed simultaneously, for example, the positive electrode plastic 104 and the negative electrode plastic 105 can be formed in the same injection molding process, which is beneficial to simplify the manufacturing process of the secondary battery, thereby reducing the manufacturing cost of the secondary battery, and reducing the factors that affect the yield of the secondary battery, thereby improving the yield of the secondary battery.

[0053] In addition, whether it is by using the lower plastic 100 doped with a conductive material in the partial area that abuts the bottom plate 112 to achieve ohmic contact between the substrate 101 and the positive electrode column 102, or by using the conductive structure 107 embedded in the end of at least one of the lower plastic 100, the positive upper plastic 104 and the positive sealing ring 106 to achieve slight conduction between the substrate 101 and the positive electrode column 102, both are conducive to making the secondary battery slightly positively charged when it is in operation, thereby avoiding corrosion of the battery cell shell or lithium deposition. Moreover, based on the slight conduction between the substrate 101 and the positive electrode column 102, that is, the transmission current between the substrate 101 and the positive electrode column 102 is extremely small, it is also conducive to avoiding the phenomenon of excessive loop current when the secondary battery short-circuits, thereby further reducing the probability of secondary battery fire, thereby improving the safety of the secondary battery.

[0054] In some cases, in conjunction with reference Figure 7 ,as well as Figures 1 to 6 , Figure 7 This is a schematic diagram of a partial cross-sectional structure of the substrate and lower plastic in a secondary battery provided in an embodiment of the present disclosure. Along the second direction Y, the positive electrode upper plastic 104 is also located between the positive electrode column 102 and the substrate 101, and the negative electrode upper plastic 105 is also located between the negative electrode column 103 and the substrate 101. It is worth noting that the substrate 101 has a second receiving hole 111 for leading out the positive electrode column 102 and a second receiving hole 121 for leading out the negative electrode column 103. In order to enable the positive electrode column 102 to penetrate the substrate 101 and the positive electrode column 102 and the substrate 101 to be spaced apart, the positive electrode upper plastic 104 is also located between the positive electrode column 102 and the substrate 101. In other words, the positive electrode upper plastic 104 has an extension portion 114 located between the positive electrode column 102 and the substrate 101. In this way, the filling property and elasticity of the plastic 104 on the positive electrode can improve the sealing effect of the plastic 104 on the positive electrode on the secondary battery, and reduce the probability of stress concentration caused by the positive electrode column 102 and the substrate 101 being subjected to force, thereby improving the safety and service life of the secondary battery.

[0055] Similarly, to ensure that the negative electrode post 103 penetrates the substrate 101 and that the negative electrode post 103 and the substrate 101 are spaced apart, the negative electrode upper plastic 105 is also located between the negative electrode post 103 and the substrate 101. In other words, the negative electrode upper plastic 105 has an extension 115 located between the negative electrode post 103 and the substrate 101. This, by leveraging the filling properties and elasticity of the negative electrode upper plastic 105, improves the sealing effect of the negative electrode upper plastic 105 on the secondary battery and reduces the probability of stress concentration caused by the negative electrode post 103 and the substrate 101, thereby improving the safety and service life of the secondary battery.

[0056] In some cases, continue to combine reference Figure 7 ,as well as Figures 1 to 6 In addition to the positive electrode sealing ring 106, the secondary battery also includes: a negative electrode sealing ring 108, which is located between the negative electrode column 103 and the lower plastic 100 along the second direction Y. It is worth noting that the positive electrode column 102 passes through the lower plastic 100 and the substrate 101 in sequence, and there is a gap between the positive electrode column 102 and both the lower plastic 100 and the substrate 101. The positive electrode sealing ring 106 and the extension 114 of the positive upper plastic 104 are both located in the gap to seal the secondary battery. Among them, the positive electrode sealing ring 106 can not only be located between the lower plastic 100 and the positive electrode column 102 along the second direction Y, but also between the substrate 101 and the positive electrode column 102. The positive electrode sealing ring 106 will be described in detail later.

[0057] Similarly, the negative electrode post 103 sequentially penetrates the lower plastic 100 and the substrate 101, with a gap between the negative electrode post 103 and both the lower plastic 100 and the substrate 101. The negative electrode sealing ring 108 and the extended portion 115 of the negative electrode upper plastic 105 together fill this gap to seal the secondary battery. The negative electrode sealing ring 108 can be located not only between the lower plastic 100 and the negative electrode post 103 along the second direction Y, but also between the substrate 101 and the negative electrode post 103. The negative electrode sealing ring 108 will be described in detail later.

[0058] In some cases, reference Figures 1 to 7 , the substrate 101 can be a plain aluminum sheet.

[0059] The position layout of the conductive structure 107 in the secondary battery is described in detail below using various embodiments.

[0060] In some embodiments, in conjunction with reference Figure 7 and Figure 3The lower plastic 100 has a first receiving hole 110 for leading out the positive electrode post 102. The conductive structure 107 is located not only on the sidewalls of the lower plastic 100 that enclose the first receiving hole 110, but also on two opposite sides of the lower plastic 100 along the first direction X. In other words, the conductive structure 107 wraps around the end of the lower plastic 100 that encloses the first receiving hole 110, and the conductive structure 107 is disposed between the positive electrode sealing ring 106 and the lower plastic 100.

[0061] Continue to combine references Figure 7 and Figure 3 In a cross-sectional view along the diameter of the positive electrode column 102, the cross-sectional shape of the conductive structure 107 is similar to a C-shape. The conductive structure 107 may include: a first connecting segment located between the substrate 101 and the lower plastic 100 along the first direction X, an extension segment located between the lower plastic 100 and the positive electrode sealing ring 106 along the second direction Y, and a second connecting segment located between the bottom plate 112 of the positive electrode column 102 and the lower plastic 100 along the first direction X. The extension segment has opposite ends along the first direction X that connect the first connecting segment and the second connecting segment, respectively. In this way, the first connecting segment achieves ohmic contact with the substrate 101, and the second connecting segment achieves ohmic contact with the bottom plate 112 of the positive electrode column 102. Furthermore, the extension segment, which simultaneously connects the first and second connecting segments, achieves micro-conductivity between the substrate 101 and the positive electrode column 102.

[0062] It is worth noting that the lower plastic 100 also has a first receiving hole 120 for leading out the negative electrode column 103. Unlike the conductive structure 107 wrapping the end of the lower plastic 100 to form the first receiving hole 110, the end of the lower plastic 100 used to form the first receiving hole 120 is directly in contact with and connected to the negative electrode sealing ring 108.

[0063] In other embodiments, in combination with reference Figure 7 and Figure 4 The positive electrode upper plastic 104 has an extension 114 located between the positive electrode post 102 and the substrate 101. The conductive structure 107 is located not only on the bottom surface of the extension 114 facing the bottom plate 112, but also on the outer and inner walls of the extension 114 that are opposite each other along the second direction Y. In other words, the conductive structure 107 wraps around the bottom end of the extension 114 facing the bottom plate 112, and the conductive structure 107 is disposed between the positive electrode sealing ring 106 and the positive electrode upper plastic 104.

[0064] Continue to combine references Figure 7 and Figure 4In a cross-sectional view along the diameter of the positive electrode post 102, the cross-sectional shape of the conductive structure 107 is similar to a U-shape. The conductive structure 107 may include: a first connecting section located between the substrate 101 and the extension portion 114 of the positive electrode plastic 104 along the second direction Y, an extension section located between the positive electrode plastic 104 and the positive electrode sealing ring 106 along the first direction X, and a second connecting section located between the extension portion 114 of the positive electrode plastic 104 and the positive electrode post 102 along the second direction Y. The extension section has opposite ends along the second direction Y connected to the first connecting section and the second connecting section, respectively. In this way, the first connecting section achieves ohmic contact with the substrate 101, and the second connecting section achieves ohmic contact with the positive electrode post 102. Furthermore, the extension section, which simultaneously connects the first and second connecting sections, achieves slight conduction between the substrate 101 and the positive electrode post 102.

[0065] It is worth noting that, unlike the conductive structure 107 wrapping the extension portion 114 toward the bottom end of the bottom plate 112, that is, the conductive structure 107 is provided between the positive electrode sealing ring 106 and the positive electrode upper plastic 104, the negative electrode column 103 sequentially penetrates the lower plastic 100 and the substrate 101, and the negative electrode sealing ring 108 and the extension portion 115 of the negative electrode upper plastic 105 together fill the space between the negative electrode column 103 and the lower plastic 100 and the substrate 101.

[0066] In some other embodiments, in combination with reference Figure 7 and Figure 5 The positive electrode sealing ring 106 has a first end portion 116 facing the lower plastic 100 . The conductive structure 107 is not only located on the sidewall of the first end portion 116 facing the lower plastic 100 , but also located on two opposite sides of the first end portion 116 along the first direction X. In other words, the conductive structure 107 wraps around the first end portion 116 .

[0067] Continue to combine references Figure 7 and Figure 5 In a cross-sectional view along the diameter of the positive electrode column 102, the cross-sectional shape of the conductive structure 107 is similar to a C-shape. The conductive structure 107 may include: a first connecting section located between the substrate 101 and the first end 116 of the positive electrode sealing ring 106 along the first direction X, an extension section located between the lower plastic 100 and the positive electrode sealing ring 106 along the second direction Y, and a second connecting section located between the bottom plate 112 of the positive electrode column 102 and the first end 116 of the positive electrode sealing ring 106 along the first direction X. The extension section has opposite ends along the first direction X that respectively connect the first connecting section and the second connecting section. In this way, the first connecting section achieves ohmic contact with the substrate 101, and the second connecting section achieves ohmic contact with the bottom plate 112 of the positive electrode column 102. Furthermore, the extension section, which simultaneously connects the first and second connecting sections, achieves slight electrical conduction between the substrate 101 and the positive electrode column 102.

[0068] It is worth noting that the lower plastic 100 also has a first receiving hole 120 for leading out the negative electrode column 103. Unlike the conductive structure 107 that wraps the first end 116 of the positive electrode sealing ring 106, that is, the conductive structure 107 is arranged between the positive electrode sealing ring 106 and the lower plastic 100, the end of the lower plastic 100 used to enclose the first receiving hole 120 is directly in contact and connected with the negative electrode sealing ring 108.

[0069] In some further embodiments, in combination with reference Figure 7 and Figure 6 The positive electrode sealing ring 106 has a second end portion 126 facing the positive electrode upper plastic 104. The conductive structure 107 is located not only on the top surface of the second end portion 126 facing the positive electrode upper plastic 104, but also on the opposite outer and inner sides of the second end portion 126 along the second direction Y. In other words, the conductive structure 107 wraps around the second end portion 126. Along the second direction Y, the second end portion 126 is located between the substrate 101 and the positive electrode column 102.

[0070] Continue to combine references Figure 7 and Figure 6 In the cross-sectional view along the diameter direction of the positive electrode column 102, the cross-sectional shape of the conductive structure 107 is similar to a U-shape. The conductive structure 107 may include: a first connecting section located between the substrate 101 and the positive electrode sealing ring 106 along the second direction Y, an extension section located between the positive electrode plastic 104 and the positive electrode sealing ring 106 along the first direction X, and a second connecting section located between the positive electrode sealing ring 106 and the positive electrode column 102 along the second direction Y, wherein the extension section is connected to the first connecting section and the second connecting section at opposite ends along the second direction Y. In this way, the first connecting section achieves ohmic contact with the substrate 101, and the second connecting section achieves ohmic contact with the positive electrode column 102, and then a slight conduction between the substrate 101 and the positive electrode column 102 is achieved by means of the extension section that simultaneously connects the first connecting section and the second connecting section.

[0071] It is worth noting that the lower plastic 100 also has a first accommodating hole 120 for leading out the negative electrode column 103. Unlike the conductive structure 107 that wraps the second end 126 of the positive electrode sealing ring 106, that is, the conductive structure 107 is provided between the positive electrode sealing ring 106 and the positive electrode upper plastic 104, the negative electrode column 103 sequentially passes through the lower plastic 100 and the substrate 101, and the negative electrode sealing ring 108 and the extended portion 115 of the negative electrode upper plastic 105 together fill the gap between the negative electrode column 103 and the lower plastic 100 and the substrate 101.

[0072] In other embodiments, reference Figure 8 , Figure 8This is a schematic diagram of the seventh partial cross-sectional structure of a secondary battery provided in an embodiment of the present disclosure. The conductive structure 107 is a conductive ceramic. The conductive ceramic is located between the lower plastic 100 and the positive electrode sealing ring 106 along the second direction Y, and the two opposite ends of the conductive ceramic along the first direction X are in ohmic contact with the substrate 101 and the bottom plate 112 of the positive electrode column 102, respectively, so that a slight conduction between the substrate 101 and the positive electrode column 102 can be achieved with the help of the conductive ceramic. In addition, compared to plastics, ceramic materials have higher stability, so the provision of conductive ceramics is beneficial to improving the pressure resistance and reliability of the secondary battery. In some cases, the pressure resistance of the secondary battery can be relatively increased by 500V or more.

[0073] It should be noted that Figure 8 Zhongyu Figures 1 to 6 The same or corresponding parts are not described here.

[0074] It is worth noting that, combined with reference Figure 8 and Figure 7 The lower plastic 100 also has a first accommodating hole 120 for leading out the negative electrode column 103. Unlike the conductive ceramic located between the lower plastic 100 and the positive electrode sealing ring 106 along the second direction Y, the end of the lower plastic 100 used to enclose the first accommodating hole 120 is directly in contact with and connected to the negative electrode sealing ring 108.

[0075] In some examples, continue to refer to Figure 8 The conductive ceramic can be considered to be partially embedded in the substrate 101 and / or partially embedded in the bottom plate 112 of the positive column 102. In other words, along the first direction X, the thickness of the conductive ceramic is greater than the thickness of the lower plastic 100.

[0076] In some examples, continue to refer to Figure 8 , the conductive ceramic can be a ceramic ring or a ceramic column.

[0077] In the various embodiments described above, reference Figures 3 to 6 Any of or Figure 8 The resistance of the conductive structure 107 may be in the range of 100Ω to 10,000Ω. For example, the resistance of the conductive structure 107 may be 200Ω, 500Ω, 700Ω, 800Ω, 1000Ω, 1500Ω, 2000Ω, 2500Ω, 3000Ω, 3500Ω, 4000Ω, 4500Ω, 5000Ω, 5500Ω, 6000Ω, 6500Ω, 7000Ω, 7500Ω, 8000Ω, 8500Ω, 9000Ω, or 9500Ω.

[0078] It is worth noting that if the resistance of the conductive structure 107 is less than 100Ω, the conductive structure 107 has too high a resistivity, and the transmission resistance between the substrate 101 and the positive electrode column 102 is too small, which easily generates a large conduction current between the substrate 101 and the positive electrode column 102. When a short circuit occurs in the secondary battery, the loop current is likely to be too large, resulting in a fire. If the resistance of the conductive structure 107 is greater than 10000Ω, the conductive structure 107 has too low a resistivity, and the transmission resistance between the substrate 101 and the positive electrode column 102 is too large, which generates a very small conduction current between the substrate 101 and the positive electrode column 102, and even makes it impossible for the substrate 101 and the positive electrode column 102 to be slightly conductive. When a short circuit occurs in the secondary battery, the risk of corrosion of the battery cell casing or lithium deposition is increased. In this way, the resistance range of the conductive structure 107 is designed to be 100Ω~10000Ω, which is conducive to making the resistance of the conductive structure 107 moderate. It is conducive to avoiding excessive loop current caused by the conductive structure 107 when the secondary battery is short-circuited, thereby further reducing the probability of secondary battery fire and improving the safety of the secondary battery. It is also conducive to ensuring that the substrate 101 and the positive electrode column 102 are slightly conductive, so as to reduce the risk of corrosion or lithium deposition of the battery cell casing.

[0079] In the various embodiments described above, reference Figures 3 to 6 Any of or Figure 8 The material of the conductive structure 107 may include a conductive polymer material or a conductive ceramic material.

[0080] It is worth noting that conductive polymers are a class of polymer materials with conductive properties. In addition to being conductive, they also offer advantages such as easy processing, light weight, corrosion resistance, and controllable conductivity. Conductive polymers are conductive composite materials prepared by synthesizing conductive polymers with conductive structures through molecular design or by incorporating conductive substances into a polymer matrix.

[0081] Conductive polymers can be categorized as structural conductive polymers and composite conductive polymers based on their structure and conductive principles. Structural conductive polymers are polymers that possess conductive properties, either inherently or through doping. For example, polyacetylene doped with a small amount of iodine or doped polysulfur nitride can be used to manufacture lightweight plastic batteries, solar cells, sensors, microwave absorbers, or semiconductor components. Composite conductive polymers are materials formed by filling a polymer matrix with various conductive substances using various processing techniques. The conductive filler provides the material's conductivity, while the polymer matrix binds the fillers together and provides processing performance. The polymer matrix can include materials such as polyethylene, polypropylene, polystyrene, epoxy resin, or phenolic resin; the conductive filler can include carbon black, carbon nanotubes, graphene, metals, or metal oxides.

[0082] In the various embodiments described above, reference Figures 3 to 6 Any of or Figure 8 , the ratio of the volume of the conductive structure 107 to the volume of the substrate 101 may be less than or equal to 3%. For example, the ratio of the volume of the conductive structure 107 to the volume of the substrate 101 may be 2.9%, 2.8%, 2.7%, 2.6%, 2.5%, 2.4%, 2.3%, 2.2%, 2.1%, 2.0%, 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%, 0.9%, 0.8%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, or 0.1%, etc.

[0083] It is worth noting that the ratio of the volume of the conductive structure 107 to the volume of the substrate 101 can be greater than 3%. In this case, the conductive structure 107 accounts for a large volume in the secondary battery, which can easily affect the assembly seal between the lower plastic 100, substrate 101, positive electrode column 102, positive electrode upper plastic 104, and positive electrode sealing ring 106, thereby affecting the sealing effect of the secondary battery. In this way, the simplified design of the ratio of the volume of the conductive structure 107 to the volume of the substrate 101 is less than or equal to 3%. This is beneficial for ensuring minimal electrical conduction between the substrate 101 and the positive electrode column 102 while minimizing the volume of the conductive structure 107, thereby improving the assembly seal between the lower plastic 100, substrate 101, positive electrode column 102, positive electrode upper plastic 104, and positive electrode sealing ring 106.

[0084] The following describes in detail the situation in which the conductive material is doped in the area where the lower plastic 100 and the bottom plate 112 abut against each other using various embodiments.

[0085] In some embodiments, reference Figure 1 The lower plastic 100 includes a first portion 130 and a second portion 140 spaced apart along the second direction Y. The first portion 130 has a first receiving hole 110 for leading out the positive electrode post 102, and the second portion 140 has a second receiving hole 121 for leading out the negative electrode post 103. The first portion 130 is doped with a conductive material. In other words, the lower plastic 100 is a split lower plastic, including at least the first portion 130 for accommodating the positive electrode post 102 and the second portion 140 for accommodating the negative electrode post 103. The first portion 130 and the second portion 140 are electrically insulated from each other.

[0086] Based on this, the first portion 130 is doped with a conductive material to ensure that the portion of the lower plastic 100 that contacts the bottom plate 112 of the positive electrode post 102 is doped with the conductive material, thereby achieving minimal electrical continuity between the substrate 101 and the positive electrode post 102. Furthermore, the electrically insulating second portion 140 ensures electrical insulation between the substrate 101 and the negative electrode post 103.

[0087] In other embodiments, reference Figure 2 The lower plastic 100 has not only a first receiving hole 110 for leading out the positive electrode 102, but also a first receiving hole 120 for leading out the negative electrode 103. The lower plastic 100 also has a contact portion 150 that abuts the bottom plate 112. A portion of the contact portion 150 is doped with a conductive material. In other words, the lower plastic 100 is a one-piece lower plastic, meaning that different areas of the same lower plastic 100 are used to accommodate the positive electrode 102 and the negative electrode 103, respectively.

[0088] Based on this, only the portion of the lower plastic 100 that contacts the bottom plate 112 , that is, at least a portion of the contact portion 150 , needs to be doped with conductive material to achieve slight conduction between the substrate 101 and the positive electrode 102 .

[0089] It should be noted that, in order to illustrate the contact portion 150 and the area of ​​the lower plastic 100 other than the contact portion 150, Figure 2 Only the area of ​​the lower plastic 100 that contacts the bottom plate 112 is filled. Furthermore, in the secondary battery provided in one embodiment of the present disclosure, the size of the contact portion 150 is not limited, as long as the bottom plate 112 is slightly conductively connected to the substrate 101 via the contact portion 150.

[0090] In the various embodiments described above, reference Figure 1 or Figure 2 The doped conductive material may include at least one of carbon black, carbon nanotubes, graphene, metal, and metal oxide.

[0091] In some embodiments, reference Figures 1 to 8 Under a test voltage of 500V, the resistance of both the positive and negative upper plastics 104 and 105 is greater than 9MΩ. In other words, compared to the conductive material-doped portion of the lower plastic 100 that contacts the bottom plate 112, or compared to the conductive structure 107, both the positive and negative upper plastics 104 and 105 have excellent insulation properties.

[0092] In some embodiments, all materials and contents used in both the positive electrode plastic 104 and the negative electrode plastic 105 can be identical. In some examples, both the positive electrode plastic 104 and the negative electrode plastic 105 can include one or more of polyphenylene sulfide (PPS), perfluoroalkoxy resin (PFA), or polypropylene (PP).

[0093] In some examples, the structures of the positive electrode plastic 104 and the negative electrode plastic 105 can also be identical. In other words, the appearance, morphology, and structural dimensions of the positive electrode plastic 104 and the negative electrode plastic 105 can be completely identical. In this way, the positive electrode plastic 104 and the negative electrode plastic 105 are completely interchangeable, and the labels used to distinguish the positive and negative poles of the positive electrode column 102 and the negative electrode column 103 can be set on other components of the secondary battery, such as on the top cover of the secondary battery.

[0094] In summary, changing the material composition of the area where the lower plastic 100 abuts the bottom plate 112 reduces the electrical resistance of the area where the lower plastic 100 abuts the bottom plate 112. This helps achieve ohmic contact between the substrate 101 and the positive electrode post 102 without adding additional components to the secondary battery, thereby simplifying the secondary battery manufacturing process and production costs. Alternatively, a conductive structure 107 can be provided within the secondary battery, embedded in the end of at least one of the lower plastic 100, the positive electrode upper plastic 104, and the positive electrode sealing ring 106, without affecting the secondary battery's appearance. Moreover, in the above two design concepts, the plastic 104 on the positive electrode and the plastic 105 on the negative electrode are both made of the same insulating material. On the one hand, it is beneficial to ensure that the plastic 104 on the positive electrode and the plastic 105 on the negative electrode have good insulation properties, high temperature resistance and long service life, thereby helping to reduce the probability of deformation of the plastic 104 on the positive electrode and the plastic 105 on the negative electrode after being subjected to force or heat. Moreover, it is beneficial to reduce the probability of the secondary battery being broken down by high voltage in the middle and late stages of use, resulting in battery cell failure, thereby improving the safety and service life of the secondary battery; the plastic 104 on the positive electrode and the plastic 105 on the negative electrode can be formed simultaneously, which is beneficial to simplify the manufacturing process of the secondary battery and reduce factors affecting the yield of the secondary battery. In addition, whether it is by using the lower plastic 100 doped with conductive material in the partial area abutting against the bottom plate 112 to achieve ohmic contact between the substrate 101 and the positive electrode column 102, or by using the conductive structure 107 embedded in the end of at least one of the lower plastic 100, the positive upper plastic 104 and the positive sealing ring 106 to achieve slight conduction between the substrate 101 and the positive electrode column 102, it is beneficial to make the secondary battery slightly positively charged on the substrate 101 when it is in working state, thereby avoiding corrosion of the battery cell casing or lithium deposition, and also helping to avoid excessive loop current when the secondary battery is short-circuited, so as to further reduce the probability of secondary battery fire, thereby improving the safety of the secondary battery.

[0095] Another embodiment of the present disclosure also provides a method for preparing a secondary battery, which is used to prepare the secondary battery provided in the aforementioned embodiment. The following detailed description of the method for preparing a secondary battery provided in another embodiment of the present disclosure is provided in conjunction with the accompanying drawings. It should be noted that parts that are identical or corresponding to the aforementioned embodiments are not repeated here.

[0096] Combined with reference Figures 1 to 7 , the preparation method of the secondary battery comprises at least the following steps:

[0097] Step S1: Provide a lower plastic 100, a substrate 101, a positive electrode column 102, a negative electrode column 103 and a positive electrode sealing ring 106. The lower plastic 100 has a first receiving hole 110 for leading out the positive electrode column 102 and a first receiving hole 120 for leading out the negative electrode column 103. The substrate 101 has a second receiving hole 111 for leading out the positive electrode column 102 and a second receiving hole 121 for leading out the negative electrode column 103.

[0098] Step S2: Reference Figure 1 or Figure 2 , doping a conductive material in a portion of the area where the lower plastic 100 abuts the positive electrode column 102 to achieve ohmic contact between a portion of the lower plastic 100 and the substrate 101 and the positive electrode column 102; or, referring to Figures 3 to 6 Any one of them forms a conductive structure 107, and the conductive structure 107 is embedded in the end of at least one of the lower plastic 100, the positive upper plastic 104 and the positive sealing ring 106, and different areas of the conductive structure 107 are in ohmic contact with the substrate 101 and the positive column 102 respectively.

[0099] Step S3: The lower plastic 100 and the substrate 101 are stacked along the first direction X; the positive electrode sealing ring 106 is placed in the first receiving hole 110, and the positive electrode column 102 is sequentially passed through the first receiving hole 110 and the second receiving hole 111 along the first direction X, so that the positive electrode sealing ring 106 is located between the positive electrode column 102 and the lower plastic 100 along the second direction Y; the negative electrode column 103 is sequentially passed through the first receiving hole 120 and the second receiving hole 121 along the first direction X.

[0100] Step S4: The positive electrode plastic 104 and the negative electrode plastic 105 are formed using the same insulating material. The positive electrode plastic 104 is sleeved on one end of the positive electrode column 102, and the negative electrode plastic 105 is sleeved on one end of the negative electrode column 103. Along the second direction Y, the positive electrode plastic 104 is also located between the positive electrode column 102 and the substrate 101.

[0101] It should be noted that two different technical concepts are provided in step S2 to achieve slight conduction between the substrate 101 and the positive electrode column 102. Step S2 will be described in detail later.

[0102] It is worth noting that in step S4, the same insulating material is used to form the positive electrode plastic 104 and the negative electrode plastic 105. Therefore, the positive electrode plastic 104 and the negative electrode plastic 105 can be formed simultaneously, which is beneficial to simplify the manufacturing process of the secondary battery, thereby reducing the manufacturing cost of the secondary battery, and reducing the factors that affect the yield of the secondary battery, thereby improving the yield of the secondary battery.

[0103] In some examples, after the positive electrode column 102 is positioned by the lower plastic 100, the positive electrode sealing ring 106 and the substrate 101 in sequence, and the negative electrode column 103 is positioned by the lower plastic 100, the negative electrode sealing ring 108 and the substrate 101 in sequence, the positive electrode upper plastic 104 and the negative electrode upper plastic 105 can be simultaneously formed by integral injection molding, thereby achieving fixation and sealing of the positive electrode column 102 and the negative electrode column 103.

[0104] The step of forming the conductive structure 107 in step S2 is described in detail below.

[0105] In some embodiments, in conjunction with reference Figure 3 and Figure 7 The lower plastic 100 has a first receiving hole 110 for leading out the positive electrode column 102; the step of embedding the conductive structure 107 into the end of the lower plastic 100 may include: providing the conductive structure 107; installing the conductive structure 107 on the lower plastic 100 to enclose the side walls of the first receiving hole 110 and the two opposite sides of the lower plastic 100 along the first direction X.

[0106] It is worth noting that the step of providing the conductive structure 107 may be: pre-preparing the conductive structure 107 with a C-shaped cross-section, with the conductive structure 107 itself forming a receiving groove; and the step of installing the conductive structure 107 on the lower plastic 100 may be: orienting the receiving groove toward the end of the lower plastic 100 that is used to form the first receiving hole 110, and sleeve the conductive structure 107 onto the lower plastic 100 so that the receiving groove receives the end of the lower plastic 100 that is used to form the first receiving hole 110. In this way, not only does the assembly steps of the secondary battery not become complicated, but the conductive structure 107 can also clearly distinguish the corresponding through-holes on the substrate 101 for the positive electrode column 102 and the negative electrode column 103 based on the conductive structure 107.

[0107] In other embodiments, the conductive structure may also be formed on the sidewalls of the lower plastic used to enclose the first receiving hole and on two opposite sides of the lower plastic along the first direction by coating.

[0108] In other embodiments, in combination with reference Figure 4 and Figure 7 The positive electrode plastic 104 has an extension portion 114 located between the positive electrode column 102 and the substrate 101. After the positive electrode column 102 is passed through the first accommodating hole 110 and the second accommodating hole 111 in sequence along the first direction X, before the positive electrode plastic 104 is formed, there is a gap between the positive electrode column 102 and the substrate 101; the step of forming the conductive structure 107 may include: forming the conductive structure 107 covering the gap, and the conductive structure 107 forms a groove; the step of forming the positive electrode plastic may include: forming the positive electrode plastic 104 to fill the groove.

[0109] In some other embodiments, in combination with reference Figure 5 and Figure 7 The positive electrode sealing ring 106 has a first end portion 116 facing the lower plastic 100, and the step of embedding the conductive structure 107 into the end portion of the positive electrode sealing ring 106 may include: providing the conductive structure 107; installing the conductive structure 107 on the side wall of the first end portion 116 facing the lower plastic 100 and on two opposite sides of the first end portion 116 along the first direction X.

[0110] It is worth noting that the step of providing the conductive structure 107 may be: pre-preparing the conductive structure 107 with a C-shaped cross-section, with the conductive structure 107 itself forming a receiving groove; the step of installing the conductive structure 107 on the first end 116 may be: orienting the receiving groove toward the first end 116 of the positive electrode sealing ring 106, and sleeve the conductive structure 107 onto the first end 116 so that the receiving groove accommodates the first end 116. In this way, not only does the assembly steps of the secondary battery not become complicated, but the conductive structure 107 can also clearly distinguish the corresponding through holes on the substrate 101 of the positive electrode column 102 and the negative electrode column 103 based on the conductive structure 107.

[0111] In other embodiments, a conductive structure may also be formed on the sidewall of the first end portion facing the lower plastic and on two opposite sides of the first end portion along the first direction by coating.

[0112] In some further embodiments, in combination with reference Figure 6 and Figure 7 The positive electrode sealing ring 106 has a second end portion 126 facing the positive electrode upper plastic 104, and the step of embedding the conductive structure 107 in the end portion of the positive electrode sealing ring 106 may include: providing the conductive structure 107; installing the conductive structure 107 on the top surface of the second end portion 126 facing the positive electrode upper plastic 104 and the opposite outer side and inner side of the second end portion 126 along the second direction Y.

[0113] It is worth noting that the step of providing the conductive structure 107 may be: pre-preparing the conductive structure 107 with a U-shaped cross-section, with the conductive structure 107 itself forming a receiving groove; the step of installing the conductive structure 107 on the second end 126 may be: orienting the receiving groove toward the second end 126 of the positive electrode sealing ring 106, and sleeve the conductive structure 107 onto the second end 126 so that the receiving groove accommodates the second end 126. In this way, not only does the assembly steps of the secondary battery not become complicated, but the conductive structure 107 can also clearly distinguish the corresponding through holes on the substrate 101 of the positive electrode column 102 and the negative electrode column 103 based on the conductive structure 107.

[0114] In other embodiments, a conductive structure may also be formed by coating on the top surface of the plastic on the second end facing the positive electrode and on the outer and inner sides of the second end facing each other along the second direction.

[0115] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the scope of protection of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A secondary battery, characterized in that: include: A lower plastic and a substrate stacked along a first direction; A positive electrode column and a negative electrode column are arranged at intervals along the second direction, the positive electrode column and the negative electrode column respectively pass through the lower plastic and the substrate in sequence along the first direction, and the positive electrode column includes a bottom plate abutting against a side of the lower plastic away from the substrate, and a main body located on the bottom plate, the main body passing through the lower plastic and the substrate; a positive electrode upper plastic sleeved on one end of the positive electrode column, and a negative electrode upper plastic sleeved on one end of the negative electrode column, wherein the positive electrode upper plastic and the negative electrode upper plastic are made of the same insulating material and have the same structure, and along the second direction, the positive electrode upper plastic is also located between the positive electrode column and the substrate; A positive electrode sealing ring, located between the positive electrode column and the lower plastic along the second direction; a conductive structure embedded in an end portion of at least one of the lower plastic, the positive electrode upper plastic, and the positive electrode sealing ring, with different regions of the conductive structure in ohmic contact with the substrate and the positive electrode column, respectively, and the conductive structure being made of a conductive polymer material or a conductive ceramic material; In which, the lower plastic has a first accommodating hole for leading out the positive electrode column, and the conductive structure is not only located on the side walls of the lower plastic used to enclose the first accommodating hole, but also on the two opposite sides of the lower plastic along the first direction; or, the positive electrode upper plastic has an extension portion located between the positive electrode column and the substrate, and the conductive structure is not only located on the bottom surface of the extension portion facing the bottom plate, but also on the outer wall and inner wall opposite to each other along the second direction.

2. The secondary battery according to claim 1, wherein The positive electrode sealing ring has a first end facing the lower plastic, and the conductive structure is not only located on the side wall of the first end facing the lower plastic, but also on two opposite sides of the first end along the first direction; Alternatively, the positive electrode sealing ring has a second end facing the plastic on the positive electrode, and the conductive structure is located not only on the top surface of the second end facing the plastic on the positive electrode, but also on the opposite outer and inner sides of the second end along the second direction.

3. The secondary battery according to claim 1 or 2, characterized in that The resistance range of the conductive structure is 100Ω~10000Ω.

4. The secondary battery according to claim 1, wherein The lower plastic includes a first portion and a second portion spaced apart along the second direction, the first portion having a first receiving hole for leading out the positive electrode column, the second portion having a second receiving hole for leading out the negative electrode column, and the first portion is doped with a conductive material.

5. The secondary battery according to claim 1 or 2, characterized in that A ratio of the volume of the conductive structure to the volume of the substrate is less than or equal to 3%.

6. The secondary battery according to claim 1, wherein Under a test voltage of 500V, the resistance of the plastic on the positive electrode and the plastic on the negative electrode are both greater than 9MΩ.

7. A method for preparing a secondary battery, characterized in that: For preparing a secondary battery according to any one of claims 1 to 6, the preparation method of the secondary battery comprising: Provide a lower plastic, a substrate, a positive electrode column, a negative electrode column, and a positive electrode sealing ring, wherein the lower plastic has a first receiving hole for leading out the positive electrode column and a first receiving hole for leading out the negative electrode column, and the substrate has a second receiving hole for leading out the positive electrode column and a second receiving hole for leading out the negative electrode column; forming a conductive structure, and embedding the conductive structure into an end portion of at least one of the lower plastic, the positive electrode upper plastic, and the positive electrode sealing ring, with different regions of the conductive structure making ohmic contact with the substrate and the positive electrode column, respectively, wherein the conductive structure is made of a conductive polymer material or a conductive ceramic material; The lower plastic has a first receiving hole for leading out the positive electrode post, and the conductive structure is located not only on the sidewalls of the lower plastic that enclose the first receiving hole, but also on two opposite sides of the lower plastic along the first direction; or the positive electrode upper plastic has an extension located between the positive electrode post and the substrate, and the conductive structure is located not only on the bottom surface of the extension facing the bottom plate, but also on the outer and inner walls of the extension that are opposite to each other along the second direction; Stacking the lower plastic and the substrate along a first direction; Placing a positive electrode sealing ring in the first receiving hole, and sequentially passing the positive electrode post through the first receiving hole and the second receiving hole along the first direction, so that the positive electrode sealing ring is located between the positive electrode post and the lower plastic along the second direction; Passing the negative electrode through the first accommodating hole and the second accommodating hole in sequence along the first direction; The positive electrode plastic and the negative electrode plastic are formed using the same insulating material, and the structures of the positive electrode plastic and the negative electrode plastic are also the same. The positive electrode plastic is sleeved on one end of the positive electrode column, and the negative electrode plastic is sleeved on one end of the negative electrode column. Along the second direction, the positive electrode plastic is also located between the positive electrode column and the substrate.

8. The method for preparing a secondary battery according to claim 7, wherein: The lower plastic has a first receiving hole for leading out the positive electrode column, the positive electrode sealing ring has a first end facing the lower plastic, and the positive electrode sealing ring has a second end facing the positive electrode upper plastic; The step of embedding the conductive structure into an end portion of at least one of the lower plastic or the positive electrode sealing ring includes: providing a conductive structure; The conductive structure is installed on the side wall of the lower plastic used to enclose the first accommodating hole and on two opposite sides of the lower plastic along the first direction; or, the conductive structure is installed on the side wall of the first end facing the lower plastic and on two opposite sides of the first end along the first direction; or, the conductive structure is installed on the top surface of the positive electrode upper plastic at the second end and on the outer and inner sides of the second end along the second direction.

9. The method for preparing a secondary battery according to claim 7, wherein: The positive electrode upper plastic has an extension portion located between the positive electrode column and the substrate, and after the positive electrode column is sequentially passed through the first receiving hole and the second receiving hole along the first direction, before the positive electrode upper plastic is formed, a gap is formed between the positive electrode column and the substrate; The step of forming the conductive structure includes: forming the conductive structure covering the gap, wherein the conductive structure forms a groove; The step of forming the plastic on the positive electrode is as follows: forming the plastic on the positive electrode so as to fill the groove.

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