Secondary battery and method for manufacturing the same

Abstract

The embodiment of the invention relates to the field of energy storage, and provides a secondary battery and a preparation method thereof, and the secondary battery comprises a lower plastic and a substrate which are arranged along a stack; the positive pole and the negative pole are arranged at an interval, the positive pole and the negative pole sequentially penetrate through the lower plastic cement and the substrate in the first direction, and the positive pole comprises a bottom plate abutting against the side, away from the substrate, of the lower plastic cement and a main body part penetrating through the lower plastic cement and the substrate; the anode upper plastic sleeves one end of the anode column, the cathode upper plastic sleeves one end of the cathode column, and the anode upper plastic and the cathode upper plastic are made of the same insulating material; the positive electrode sealing ring is positioned between the positive electrode column and the lower plastic cement; a conductive material is doped in a partial region where the lower plastic cement is abutted against the bottom plate; or the secondary battery further comprises a conductive structure which is embedded into the end part of at least one of the lower plastic, the positive upper plastic and the positive sealing ring, and different areas of the conductive structure are respectively in ohmic contact with the substrate and the positive pole, so that the ohmic contact of the positive pole and the substrate is at least favorably realized, and the safety of the secondary battery is improved.

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] At present, in the field of energy storage, in order to ensure the safety of secondary batteries during use, hard shells are usually used to assemble the battery cells, and the hard shells that contain the battery cells are generally made of metal materials. In order to avoid 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 precipitation, it is necessary to connect the substrate and the positive pole of the secondary battery so that the substrate is positively charged to solve the shell corrosion problem. However, if metal is used to directly connect the substrate and the positive pole of the secondary battery, since the resistance value of the metal is generally in the milliohm level, when the secondary battery is short-circuited, its loop current will increase sharply, which is prone to ignition and fire and other safety hazards.

[0003] However, in order to solve the problems of shell corrosion and excessive loop current of secondary batteries, the plastic on the positive electrode is usually designed to have a certain conductivity. This not only makes it impossible to prepare the plastic on the positive electrode and the plastic on the negative electrode simultaneously, 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 late 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 the ohmic contact between the positive electrode column and the substrate and improve the safety of the secondary battery.

[0005] According to some embodiments of the present disclosure, on the one hand, the embodiments of the present disclosure provide 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 penetrate 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 penetrates the lower plastic and the substrate; a positive electrode upper plastic sleeved at one end of the positive electrode column, and a negative electrode upper plastic sleeved at 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 against 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 side wall of the lower plastic for surrounding 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 upper 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 at the side wall of the first end facing the lower plastic, but also at 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 at the top surface of the second end facing the positive electrode upper plastic, but also at 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 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 the conductive material.

[0012] In some embodiments, a ratio of a volume of the conductive structure to a 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 resistance of 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 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; doping a conductive material in a partial area where the lower plastic abuts against 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 The positive electrode column and the lower plastic are respectively in ohmic contact with the substrate and the positive electrode column; the lower plastic and the substrate are stacked and arranged along the first direction; a positive electrode sealing ring is placed in the first accommodating hole, and the positive electrode column is sequentially passed through the first accommodating hole and the second accommodating hole 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; the negative electrode column is sequentially passed through the first accommodating hole and the second accommodating hole along the first direction; the positive electrode upper plastic and the negative electrode upper plastic are formed by using the same insulating material, 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 lower plastic facing the first end and the two opposite sides of the first end along the first direction; or, installing the conductive structure on the second end facing the top surface of the positive electrode upper plastic and the second end on the opposite outer and inner sides along 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, 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 that fills the groove.

[0017] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: Changing the material composition of the area where the lower plastic abuts against the bottom plate in the substrate to reduce the resistance of the area where the lower plastic abuts against the bottom plate is beneficial to achieving ohmic contact between the substrate and the positive electrode column without adding additional components of the secondary battery, that is, without affecting the structural changes of the battery cell, and is beneficial to simplifying the manufacturing process and preparation cost of the secondary battery as much as possible. Alternatively, a conductive structure is provided inside the secondary battery, so that the conductive structure is embedded in the end of at least one of the lower plastic, the positive electrode upper plastic and the positive electrode sealing ring, which will not affect 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 deformation of the plastic on the positive electrode and the plastic on the negative electrode after being subjected to force or heat, and it is also conducive to reducing the probability of secondary batteries 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 batteries; 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 the 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 against 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 a working state, thereby avoiding corrosion of the battery cell casing or lithium precipitation, and it is also beneficial 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

[0018] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, 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 are 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 creative work.

[0019] Figure 1 A schematic diagram of a first partial cross-sectional structure of a secondary battery provided by an embodiment of the present disclosure; Figure 2A schematic diagram of a second partial cross-sectional structure of a secondary battery provided by an embodiment of the present disclosure; Figure 3 A third partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 4 A fourth partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 5 A fifth partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 6 A sixth partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 7 A schematic diagram of a partial cross-sectional structure of a substrate and a lower plastic in a secondary battery provided by an embodiment of the present disclosure; Figure 8 A seventh partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] As can be seen from the background technology, the safety of secondary batteries needs to be further improved.

[0021] 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, such as adding carbon nanotubes to the insulating material to reduce the resistance of the plastic on the positive electrode and reduce the insulating properties of the plastic on the positive electrode.

[0022] Thus, 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, so that in certain safety experiments, such as short circuit or thermal runaway, the plastic on the positive electrode is more easily 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 is likely to lead to a decrease in the insulation and storage performance of the plastic on the positive electrode. In the current energy storage field, where there is a demand for high voltage and long life, the secondary battery is very likely to be broken down by high voltage in the middle and late stages of use, resulting in 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 use different materials, different processes need to be used for processing 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.

[0023] The present disclosure provides a secondary battery and a method for preparing the same. In the secondary battery, the material composition of the area where the lower plastic contacts the bottom plate is changed to reduce the resistance of the area where the lower plastic contacts the bottom plate, which is beneficial to achieving ohmic contact between the substrate and the positive electrode column without adding additional components to the secondary battery, that is, without affecting the structural changes of the battery cell, and is beneficial to simplifying the manufacturing process and preparation cost of the secondary battery as much as possible. Alternatively, a conductive structure is provided inside the secondary battery so that the conductive structure is embedded in the end of at least one of the lower plastic, the positive electrode upper plastic, and the positive electrode sealing ring, which will not affect 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 deformation of the plastic on the positive electrode and the plastic on the negative electrode after being subjected to force or heat, and it is also conducive to reducing the probability of secondary batteries 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 batteries; 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 the 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 against 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 a working state, thereby avoiding corrosion of the battery cell casing or lithium precipitation, and it is also beneficial 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.

[0024] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0027] 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).

[0028] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0029] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0030] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component 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 exist between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0031] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located 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 exist in between. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located in between.

[0032] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the components" are also intended to include plural forms unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0033] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable the reader to better understand the embodiments of the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can be implemented.

[0034] An embodiment of the present disclosure provides a secondary battery, which will be described in detail below with reference to the accompanying drawings.

[0035] refer to Figures 1 to 6 The secondary battery comprises: 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 penetrate the lower plastic 100 and the substrate 101 in sequence along the first direction X, and the positive electrode column 102 comprises 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, and 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.

[0036] Among them, reference Figure 1 or Figure 2A conductive material is doped in a partial area where the lower plastic 100 abuts against the bottom plate 112 to achieve ohmic contact between a partial area of ​​the lower plastic 100 and the substrate 101 and the bottom plate 112 .

[0037] 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.

[0038] It should be noted that Figure 1 A schematic diagram of a first partial cross-sectional structure of a secondary battery provided by an embodiment of the present disclosure; Figure 2 A schematic diagram of a second partial cross-sectional structure of a secondary battery provided by an embodiment of the present disclosure; Figure 3 A third partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 4 A fourth partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 5 A fifth partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure; Figure 6 A sixth partial cross-sectional structural schematic diagram of a secondary battery provided in one embodiment of the present disclosure.

[0039] In addition, one Figures 1 to 6 In 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, and 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.

[0040] 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 an embodiment of the present disclosure includes at least the following two design concepts.

[0041] First, refer to 1 or Figure 2, the material composition of the partial area where the lower plastic 100 abuts against the bottom plate 112 is changed to reduce the resistance of the partial area where the lower plastic 100 abuts against the bottom plate 112, and the other areas of the lower plastic 100 still have excellent insulation properties, so that it is beneficial to achieve ohmic contact between the substrate 101 and the positive electrode column 102 by modifying the partial area where the lower plastic 100 abuts against the bottom plate 112 without adding additional components of the secondary battery, which is beneficial to simplify the manufacturing process and preparation cost of the secondary battery as much as possible.

[0042] Second, reference Figures 3 to 6 In any one of the above, a conductive structure 107 is disposed 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, which will not affect the appearance of the secondary battery.

[0043] 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 for the material design of the plastic 104 on the positive electrode to make a balanced choice between having certain conductive 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, and also helping to reduce the probability of failure of the secondary battery due to high voltage breakdown in the middle and late stages of use, thereby improving the safety and service life of the secondary battery.

[0044] On the other hand, the plastic 104 on the positive electrode and the plastic 105 on the negative electrode are both made of the same insulating material, so the plastic 104 on the positive electrode and the plastic 105 on the negative electrode can be formed simultaneously, for example, the plastic 104 on the positive electrode and the plastic 105 on the negative electrode 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.

[0045] In addition, whether the ohmic contact between the substrate 101 and the positive electrode column 102 is achieved by means of the lower plastic 100 doped with conductive material in the partial area abutting against the bottom plate 112, or the slight conduction between the substrate 101 and the positive electrode column 102 is achieved by means of the 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, it is beneficial to make the secondary battery slightly positively charged on the substrate 101 when it is in working state, thereby avoiding the phenomenon of corrosion or lithium precipitation of the battery cell shell. 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 beneficial to avoid the phenomenon of excessive loop current when the secondary battery is short-circuited, so as to further reduce the probability of fire of the secondary battery, thereby improving the safety of the secondary battery.

[0046] In some cases, in conjunction with reference Figure 7 ,as well as Figures 1 to 6 , Figure 7 A partial cross-sectional structural diagram of the substrate and the lower plastic in the secondary battery provided in one 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 realize the penetration of the positive electrode column 102 through the substrate 101, and the positive electrode column 102 and the substrate 101 are arranged at intervals, 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 help 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 helping to improve the safety and service life of the secondary battery.

[0047] Similarly, in order to realize the penetration of the negative electrode column 103 through the substrate 101, and the negative electrode column 103 and the substrate 101 are arranged at intervals, the negative electrode upper plastic 105 is also located between the negative electrode column 103 and the substrate 101. In other words, the negative electrode upper plastic 105 has an extension portion 115 located between the negative electrode column 103 and the substrate 101. In this way, with the filling property and elasticity of the negative electrode upper plastic 105, it is beneficial to improve the sealing effect of the negative electrode upper plastic 105 on the secondary battery, and reduce the probability of stress concentration caused by the negative electrode column 103 and the substrate 101 being subjected to force, thereby helping to improve the safety and service life of the secondary battery.

[0048] In some cases, continue to combine reference Figure 7 ,as well as Figures 1 to 6In 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 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.

[0049] Similarly, the negative electrode column 103 sequentially penetrates the lower plastic 100 and the substrate 101, and there is a gap between the negative electrode column 103 and both the lower plastic 100 and the substrate 101. The negative electrode sealing ring 108 and the extension 115 of the negative electrode upper plastic 105 fill the gap together to seal the secondary battery. Among them, the negative electrode sealing ring 108 can be located not only between the lower plastic 100 and the negative electrode column 103 along the second direction Y, but also between the substrate 101 and the negative electrode column 103. The negative electrode sealing ring 108 will be described in detail later.

[0050] In some cases, reference Figures 1 to 7 , the substrate 101 can be a plain aluminum sheet.

[0051] The position layout of the conductive structure 107 in the secondary battery is described in detail below using various embodiments.

[0052] In some embodiments, in conjunction with reference Figure 7 and Figure 3 , the lower plastic 100 has a first receiving hole 110 for leading out the positive electrode column 102 , and the conductive structure 107 is not only located on the side wall of the lower plastic 100 for surrounding the first receiving hole 110 , but also located on two opposite sides of the lower plastic 100 along the first direction X. In other words, the conductive structure 107 wraps the end of the lower plastic 100 for surrounding the first receiving hole 110 , and the conductive structure 107 is disposed between the positive electrode sealing ring 106 and the lower plastic 100 .

[0053] Continue to combine references Figure 7 and Figure 3, 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 C shape. The conductive structure 107 may include: a first connecting section located between the substrate 101 and the lower plastic 100 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 lower plastic 100 along the first direction X, and the extension section is connected to the first connecting section and the second connecting section at opposite ends along the first direction X. In this way, the first connecting section realizes ohmic contact with the substrate 101, and the second connecting section realizes ohmic contact with the bottom plate 112 of the positive electrode column 102, and then the substrate 101 and the positive electrode column 102 are slightly conductive by means of the extension section that simultaneously connects the first connecting section and the second connecting section.

[0054] 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.

[0055] In other embodiments, in combination with reference Figure 7 and Figure 4 , the positive electrode upper plastic 104 has an extension portion 114 located between the positive electrode column 102 and the substrate 101, and the conductive structure 107 is not only located on the bottom surface of the extension portion 114 facing the bottom plate 112, but also located on the outer wall and inner wall opposite to each other in the second direction Y of the extension portion 114. In other words, the conductive structure 107 wraps the bottom end of the extension portion 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.

[0056] Continue to combine references Figure 7 and Figure 4 , 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 extension portion 114 of the plastic 104 on the positive electrode along the second direction Y, an extension section located between the plastic 104 on the positive electrode 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 plastic 104 on the positive electrode and the positive electrode column 102 along the second direction Y, and 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 realizes ohmic contact with the substrate 101, and the second connecting section realizes ohmic contact with the positive electrode column 102, and then the substrate 101 and the positive electrode column 102 are slightly conductive by means of the extension section that simultaneously connects the first connecting section and the second connecting section.

[0057] 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 arranged between the positive electrode sealing ring 106 and the positive electrode upper plastic 104, the negative electrode column 103 passes through the lower plastic 100 and the substrate 101 in sequence, and the negative electrode sealing ring 108 and the extension 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.

[0058] In some other embodiments, in combination with reference Figure 7 and Figure 5 The positive electrode sealing ring 106 has a first end 116 facing the lower plastic 100 , and the conductive structure 107 is not only located on the side wall of the first end 116 facing the lower plastic 100 , but also located on two opposite sides of the first end 116 along the first direction X. In other words, the conductive structure 107 wraps the first end 116 .

[0059] Continue to combine references Figure 7 and Figure 5 , 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 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, and the extension section is connected to the first connecting section and the second connecting section at opposite ends along the first direction X. In this way, the first connecting section realizes ohmic contact with the substrate 101, and the second connecting section realizes ohmic contact with the bottom plate 112 of the positive electrode column 102, and then the substrate 101 and the positive electrode column 102 are slightly conductive by means of the extension section that simultaneously connects the first connecting section and the second connecting section.

[0060] It is worth noting that the lower plastic 100 also has a first receiving hole 120 for leading out the negative electrode column 103. Different from the conductive structure 107 wrapping 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.

[0061] In some further embodiments, in combination with reference Figure 7 and Figure 6, the positive electrode sealing ring 106 has a second end 126 facing the positive electrode upper plastic 104, and the conductive structure 107 is not only located on the top surface of the second end 126 facing the positive electrode upper plastic 104, but also located on the opposite outer and inner sides of the second end 126 along the second direction Y. In other words, the conductive structure 107 wraps the second end 126, and along the second direction Y, the second end 126 is located between the substrate 101 and the positive electrode column 102.

[0062] 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, and 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 realizes ohmic contact with the substrate 101, the second connecting section realizes ohmic contact with the positive electrode column 102, and then the substrate 101 and the positive electrode column 102 are slightly conductive by means of the extension section that simultaneously connects the first connecting section and the second connecting section.

[0063] It is worth noting that the lower plastic 100 also has a first accommodating hole 120 for leading out the negative electrode column 103. Different from the conductive structure 107 wrapping the second end 126 of the positive electrode sealing ring 106, that is, the conductive structure 107 is arranged between the positive electrode sealing ring 106 and the positive electrode upper plastic 104, the negative electrode column 103 passes through the lower plastic 100 and the substrate 101 in sequence, 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.

[0064] In other embodiments, reference Figure 8 , Figure 8 The seventh partial cross-sectional structural schematic diagram 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 the substrate 101 and the positive electrode column 102 can be slightly conductive with the help of the conductive ceramic. In addition, compared with plastics, ceramic materials have higher stability, so the provision of conductive ceramics is conducive to improving the compressive strength and reliability of the secondary battery. In some cases, the compressive strength of the secondary battery can be relatively increased by 500V and above.

[0065] It should be noted that Figure 8 Zhongyu Figures 1 to 6 The same or corresponding parts in the drawings will not be described in detail here.

[0066] It is worth noting that, combined with reference Figure 8 and Figure 7 The lower plastic 100 also has a first receiving 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 receiving hole 120 is directly in contact with and connected to the negative electrode sealing ring 108.

[0067] 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 electrode 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.

[0068] In some examples, continue to refer to Figure 8 , the conductive ceramic can be a ceramic ring or a ceramic column.

[0069] In the above various embodiments, reference Figures 3 to 6 Any of or Figure 8 , the resistance range of the conductive structure 107 can be 100Ω~10000Ω. For example, the resistance of the conductive structure 107 can be 200Ω, 500Ω, 700Ω, 800Ω, 1000Ω, 1500Ω, 2000Ω, 2500Ω, 3000Ω, 3500Ω, 4000Ω, 4500Ω, 5000Ω, 5500Ω, 6000Ω, 6500Ω, 7000Ω, 7500Ω, 8000Ω, 8500Ω, 9000Ω or 9500Ω, etc.

[0070] 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 too large and fire is likely to occur; 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 fails to make the substrate 101 and the positive electrode column 102 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 beneficial to avoid excessive loop current caused by the conductive structure 107 when a short circuit occurs in the secondary battery, thereby further reducing the probability of secondary battery fire and improving the safety of the secondary battery. It is also beneficial to ensure 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.

[0071] In the above various embodiments, 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.

[0072] It is worth noting that conductive polymer materials are a type of polymer materials with conductive properties. In addition to being conductive, they also have the advantages of easy processing, light weight, corrosion resistance, and adjustable conductive properties. Conductive polymer materials are conductive composite materials prepared by synthesizing conductive polymers with conductive structures through molecular design or by adding conductive substances into polymer matrices.

[0073] According to the different structures and conductive principles, conductive polymer materials can be divided into structural conductive polymer materials and composite conductive polymer materials. First, structural conductive polymer materials refer to polymer materials that have conductive functions in the polymer structure itself or after doping, for example, polyacetylene doped with a small amount of iodine or polysulfur nitride after doping. Structural conductive polymer materials can be used to prepare lightweight plastic batteries, solar cells, sensors, microwave absorbing materials or semiconductor components. Second, composite conductive polymer materials are materials composed of various conductive substances filled in a polymer matrix with different processing techniques. The conductive filler provides the conductive properties of the material, and the polymer matrix bonds the conductive filler together and provides the processing properties of the material. The materials of the polymer matrix can include polyethylene, polypropylene, polystyrene, epoxy resin or phenolic resin, etc.; the conductive filler can include carbon black, carbon nanotubes, graphene, metal or metal oxide, etc.

[0074] In the above various embodiments, 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.

[0075] 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%, and the conductive structure 107 accounts for a large volume in the secondary battery, which is easy to affect the assembly sealing between the lower plastic 100, the substrate 101, the positive electrode column 102, the positive electrode upper plastic 104 and the positive electrode sealing ring 106, thereby affecting the sealing effect of the secondary battery. In this way, the ratio of the volume of the conductive structure 107 to the volume of the substrate 101 is designed to be less than or equal to 3%, which is conducive to ensuring slight conduction between the substrate 101 and the positive electrode column 102, while reducing the volume of the conductive structure 107 as much as possible, so as to improve the assembly sealing between the lower plastic 100, the substrate 101, the positive electrode column 102, the positive electrode upper plastic 104 and the positive electrode sealing ring 106.

[0076] The following describes in detail the situation in which the conductive material is doped in the partial area where the lower plastic 100 and the bottom plate 112 abut against each other using various embodiments.

[0077] 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 column 102, the second portion 140 has a second receiving hole 121 for leading out the negative electrode column 103, and the first portion 130 is doped with a conductive material. In other words, the lower plastic 100 is a split lower plastic, at least including the first portion 130 for accommodating the positive electrode column 102, and the second portion 140 for accommodating the negative electrode column 103, and the first portion 130 and the second portion 140 are electrically insulated from each other.

[0078] Based on this, the first part 130 is doped with a conductive material, so that the conductive material can be doped in the partial area of ​​the lower plastic 100 that abuts against the bottom plate 112 of the positive electrode column 102, so as to achieve slight conduction between the substrate 101 and the positive electrode column 102. The electrical insulation of the substrate 101 and the negative electrode column 103 is ensured by the electrically insulating second part 140.

[0079] In other embodiments, reference Figure 2 The lower plastic 100 has not only a first receiving hole 110 for leading out the positive electrode column 102, but also a first receiving hole 120 for leading out the negative electrode column 103, and the lower plastic 100 has a contact portion 150 abutting against the bottom plate 112, and a part of the contact portion 150 is doped with a conductive material. In other words, the lower plastic 100 is an integrated lower plastic, that is, different areas of the same lower plastic 100 are used to accommodate the positive electrode column 102 and the negative electrode column 103 respectively.

[0080] Based on this, it is only necessary to design the portion of the lower plastic 100 that contacts the bottom plate 112 , that is, at least a portion of the contact portion 150 is doped with conductive material to achieve slight conduction between the substrate 101 and the positive electrode column 102 .

[0081] 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 In the drawing method, only the partial area of ​​the lower plastic 100 that contacts the bottom plate 112 is filled. In addition, in the secondary battery provided by an embodiment of the present disclosure, the size of the contact portion 150 is not limited, and the bottom plate 112 can be slightly conductive with the substrate 101 through the contact portion 150.

[0082] In the above various embodiments, 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.

[0083] In some embodiments, reference Figures 1 to 8 , under a test voltage of 500 V, the resistance of the positive electrode upper plastic 104 and the negative electrode upper plastic 105 are both greater than 9 MΩ. In other words, compared to the portion of the lower plastic 100 doped with conductive material and abutting against the bottom plate 112, or compared to the conductive structure 107, the positive electrode upper plastic 104 and the negative electrode upper plastic 105 both have good insulation properties.

[0084] In some embodiments, all materials and contents used in the positive electrode plastic 104 and the negative electrode plastic 105 can be exactly the same. In some examples, the material of the positive electrode plastic 104 and the material of the negative electrode plastic 105 can both include one or more of polyphenylene sulfide (PPS), perfluoroalkoxy resin (PFA), or polypropylene (PP).

[0085] In some examples, the structures of the positive electrode plastic 104 and the negative electrode plastic 105 may be the same. In other words, the appearance, morphology and structural dimensions of the positive electrode plastic 104 and the negative electrode plastic 105 may be completely the same. In this way, the positive electrode plastic 104 and the negative electrode plastic 105 may be completely interchangeable, and the numbers for distinguishing the positive and negative electrodes of the positive electrode column 102 and the negative electrode column 103 may be set in other components of the secondary battery, such as on the top cover of the secondary battery.

[0086] In summary, changing the material composition of the part of the area where the lower plastic 100 abuts against the bottom plate 112 to reduce the resistance of the part of the area where the lower plastic 100 abuts against the bottom plate 112 is beneficial to achieve ohmic contact between the substrate 101 and the positive electrode column 102 without adding additional components of the secondary battery, which is beneficial to simplify the manufacturing process and preparation cost of the secondary battery as much as possible. Alternatively, 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, which will not affect the appearance of the secondary battery. 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 conducive to 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, 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 it is also conducive to reducing the probability of failure of the secondary battery due to high voltage breakdown in the middle and late stages of use, 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 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 100 doped with conductive material in a 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 precipitation, and also helping to avoid excessive loop current when the secondary battery is short-circuited, so as to further reduce the probability of fire of the secondary battery, thereby improving the safety of the secondary battery.

[0087] Another embodiment of the present disclosure also provides a method for preparing a secondary battery, which is used to prepare the secondary battery provided by the above embodiment. The method for preparing a secondary battery provided by another embodiment of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or corresponding to the above embodiment will not be repeated here.

[0088] Combined with reference Figures 1 to 7 , the preparation method of the secondary battery comprises at least the following steps: 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, wherein 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, and 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.

[0089] Step S2: Reference Figure 1 or Figure 2 , doping a conductive material in a partial area where the lower plastic 100 abuts against the positive electrode column 102 to achieve ohmic contact between a partial area 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.

[0090] Step S3: stack the lower plastic 100 and the substrate 101 along the first direction X; place the positive electrode sealing ring 106 in the first receiving hole 110, and pass the positive electrode column 102 through the first receiving hole 110 and the second receiving hole 111 in sequence 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; pass the negative electrode column 103 through the first receiving hole 120 and the second receiving hole 121 in sequence along the first direction X.

[0091] Step S4: The same insulating material is used to form the positive electrode plastic 104 and the negative electrode plastic 105. 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. In addition, along the second direction Y, the positive electrode plastic 104 is also located between the positive electrode column 102 and the substrate 101.

[0092] 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 , and step S2 will be described in detail later.

[0093] 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, so 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.

[0094] 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.

[0095] The step of forming the conductive structure 107 in step S2 is described in detail below.

[0096] 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 a 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.

[0097] It is worth noting that the step of providing the conductive structure 107 may be: preparing in advance a conductive structure 107 with a cross-sectional shape similar to a C-shape, and the conductive structure 107 itself encloses a receiving groove; the step of installing the conductive structure 107 on the lower plastic 100 may be: directing the receiving groove toward the end of the lower plastic 100 for enclosing the first receiving hole 110, and sleeve the conductive structure 107 on the lower plastic 100, so that the receiving groove accommodates the end of the lower plastic 100 for enclosing the first receiving hole 110. In this way, not only will the assembly steps of the secondary battery not be complicated, but based on the conductive structure 107, the corresponding through holes of the positive electrode column 102 and the negative electrode column 103 on the substrate 101 can be clearly distinguished.

[0098] In other embodiments, a conductive structure may also be formed on the sidewalls of the lower plastic used to surround the first receiving hole and on two opposite sides of the lower plastic along the first direction by coating.

[0099] 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 a conductive structure 107 covering the gap, and the conductive structure 107 surrounds a groove; the step of forming the positive electrode plastic may include: forming the positive electrode plastic 104 filling the groove.

[0100] In some other embodiments, in combination with reference Figure 5 and Figure 7 The positive electrode sealing ring 106 has a first end 116 facing the lower plastic 100, and the step of embedding the conductive structure 107 into the end of the positive electrode sealing ring 106 may include: providing a conductive structure 107; installing the conductive structure 107 on the side wall of the first end 116 facing the lower plastic 100 and on two opposite sides of the first end 116 along the first direction X.

[0101] It is worth noting that the step of providing the conductive structure 107 may be: preparing in advance a conductive structure 107 with a cross-sectional shape similar to a C-shape, and the conductive structure 107 itself encloses a receiving groove; the step of installing the conductive structure 107 on the first end 116 may be: directing the receiving groove toward the first end 116 of the positive electrode sealing ring 106, and sleeve the conductive structure 107 on the first end 116, so that the receiving groove receives the first end 116. In this way, not only will the assembly steps of the secondary battery not be complicated, but based on the conductive structure 107, the corresponding through holes of the positive electrode column 102 and the negative electrode column 103 on the substrate 101 can be clearly distinguished.

[0102] In other embodiments, a conductive structure may also be formed on the sidewall of the first end facing the lower plastic and on two opposite sides of the first end along the first direction by coating.

[0103] In some further embodiments, in combination with reference Figure 6 and Figure 7 The positive electrode sealing ring 106 has a second end 126 facing the positive electrode plastic 104, and the step of embedding the conductive structure 107 into the end 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 126 facing the positive electrode plastic 104 and the outer side and the inner side of the second end 126 opposite to each other along the second direction Y.

[0104] It is worth noting that the step of providing the conductive structure 107 may be: preparing in advance a conductive structure 107 with a U-shaped cross-section, and the conductive structure 107 itself forms a receiving groove; the step of installing the conductive structure 107 on the second end 126 may be: directing the receiving groove toward the second end 126 of the positive electrode sealing ring 106, and sleeve the conductive structure 107 on the second end 126, so that the receiving groove receives the second end 126. In this way, not only will the assembly steps of the secondary battery not be complicated, but based on the conductive structure 107, the corresponding through holes of the positive electrode column 102 and the negative electrode column 103 on the substrate 101 can be clearly distinguished.

[0105] 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 side and the inner side of the second end facing each other along the second direction.

[0106] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can 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 can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure, so the protection scope 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 penetrate 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, and the main body penetrates 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 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; Among them, the partial area where the lower plastic abuts against 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.

2. The secondary battery according to claim 1, characterized in that: The lower plastic has a first receiving hole for leading out the positive pole, and the conductive structure is not only located on the side wall of the lower plastic for surrounding the first receiving hole, but also located on two opposite sides of the lower plastic along the first direction.

3. The secondary battery according to claim 1, characterized in that: The positive electrode upper 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 of the extension portion.

4. The secondary battery according to claim 1, characterized in that: 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 located 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 not only located on the top surface of the second end facing the plastic on the positive electrode, but also located on the opposite outer and inner sides of the second end along the second direction.

5. The secondary battery according to any one of claims 2 to 4, characterized in that: The resistance range of the conductive structure is 100Ω~10000Ω; and / or, the material of the conductive structure includes conductive polymer material or conductive ceramic material.

6. The secondary battery according to claim 1, characterized in that: The conductive material includes at least one of carbon black, carbon nanotubes, graphene, metal, and metal oxide.

7. The secondary battery according to claim 1 or 6, characterized in that: 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 the conductive material.

8. The secondary battery according to any one of claims 2 to 4, 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%.

9. The secondary battery according to claim 1, characterized in that: 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.

10. A method for preparing a secondary battery, characterized in that: include: 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 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; Doping a conductive material in a partial area where the lower plastic abuts against 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 making the conductive structure embedded in an 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; 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 column 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 column and the lower plastic along the second direction; Passing the negative electrode column through the first receiving hole and the second receiving hole in sequence along the first direction; The same insulating material is used to form the positive electrode plastic and the negative electrode plastic. 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.

11. The method for preparing a secondary battery according to claim 10, characterized in that: The lower plastic has a first receiving hole 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 comprises: Providing a conductive structure; The conductive structure is installed on the lower plastic to enclose the side wall of the first accommodating hole and the two opposite sides of the lower plastic along the first direction; or, the conductive structure is installed on the first end facing the side wall of the lower plastic and the two opposite sides of the first end along the first direction; or, the conductive structure is installed on the second end facing the top surface of the positive electrode upper plastic and the outer side and inner side of the second end along the second direction.

12. The method for preparing a secondary battery according to claim 10, characterized in that: 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 passed through the first receiving hole and the second receiving hole in sequence along the first direction, before the positive electrode upper plastic 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, 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 to fill the groove.

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