Current collectors, electrode plates, electrode assemblies, battery cells, batteries, and electrical devices.

Abstract

The present application relates to the technical field of batteries, and relates in particular to a current collector, an electrode plate, an electrode assembly, a battery cell, a battery, and an electrical device. The current collector comprises: a supporting layer; and a conductive layer, which is provided on at least one side of two opposite sides of the supporting layer and shrinks along with the supporting layer when the supporting layer is heated and contracted so as to form a hole surrounding a heated part, the conductive layer comprising a first conductive layer that makes contact with the supporting layer, and the first conductive layer being a granular conductive layer. On the basis of the foregoing, the safety performance may be improved.

Description

Current collector, electrode sheet, electrode assembly, battery cell, battery and electrical device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese application with application number 202122614507.4 and application date October 28, 2021, and claims its priority. The disclosed content of the Chinese application is hereby introduced as a whole into this application. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a current collector, an electrode sheet, an electrode assembly, a battery cell, a battery, and an electrical device. Background Art

[0004] With the rapid development of electronic products, electric vehicles, and other electrical devices, batteries are increasingly being used. However, batteries are prone to short circuits, which can cause thermal runaway and compromise operational safety.

[0005] Summary of the Invention

[0006] The present application aims to provide a current collector, electrode sheet, electrode assembly, battery cell, battery and electrical device with higher safety performance.

[0007] In order to achieve the above objectives, the current collector provided in this application includes:

[0008] a support layer; and

[0009] The conductive layer is arranged on at least one of the two opposite sides of the support layer, and when the support layer shrinks due to heat, it shrinks along with the support layer to form a hole surrounding the heated part. The conductive layer includes a first conductive layer in contact with the support layer, and the first conductive layer is a granular conductive layer.

[0010] Under the action of the supporting layer and the conductive layer, the current collector can quickly cut off the failed circuit and prevent thermal runaway, thus effectively improving safety performance.

[0011] In some embodiments, the granular conductive layer includes a metal particle layer, thereby enabling the current collector to have good conductive properties.

[0012] In some embodiments, the metal particle layer includes a copper particle layer, an aluminum particle layer, a gold particle layer, a silver particle layer, or an alloy particle layer, thereby effectively improving the conductive properties of the current collector.

[0013] In some embodiments, the resistivity of the alloy in the alloy particle layer is less than or equal to 30·10 -9 Ω·m. In this way, the current collector can have better conductive properties.

[0014] In some embodiments, the first conductive layer is sprayed onto the support layer, thereby making it easy to composite the granular conductive layer onto the support layer.

[0015] In some embodiments, the conductive layer includes a second conductive layer electrically connected to a surface of the granular conductive layer facing away from the support layer, thereby enhancing the conductive capability of the conductive layer.

[0016] In some embodiments, the second conductive layer is bonded to the first conductive layer, thereby facilitating the connection between the first conductive layer and the second conductive layer, achieving a strong connection, and facilitating electrical connection between the first conductive layer and the second conductive layer.

[0017] In some embodiments, the second conductive layer includes a graphite layer, thereby more effectively improving the conductive performance of the conductive layer.

[0018] In some embodiments, the conductivity of the conductive layer is 10 4 ~10 5 S / cm. At this point, the conductive layer can better meet the conductivity requirements of the current collector and effectively prevent the battery cell from generating excessive heat during normal charging and discharging.

[0019] In some embodiments, the melting point of the support layer is less than or equal to 120°. Therefore, the support layer is more likely to melt and shrink before other parts melt, thus cutting off the failure circuit. Therefore, thermal runaway can be more reliably prevented, and safety performance can be more effectively improved.

[0020] In some embodiments, the support layer is a support film. In this case, the current collector not only has better safety performance but also has stronger structural stability.

[0021] In some embodiments, the support layer is made of a high molecular organic material. The support layer made of a high molecular organic material can quickly cut off the failed circuit when needed, prevent thermal runaway, and improve safety performance.

[0022] In some embodiments, the support layer is a polyethylene film, which can not only effectively prevent thermal runaway but also enhance the bending resistance of the current collector.

[0023] The electrode sheet provided in the present application includes an active material and also includes a current collector according to an embodiment of the present application, wherein the active material is disposed on the surface of the current collector.

[0024] Since the current collector according to the embodiment of the present application is included, the electrode sheet has higher safety performance.

[0025] The electrode assembly provided in this application includes:

[0026] positive electrode; and

[0027] negative electrode;

[0028] Among them, the positive electrode sheet and / or the negative electrode sheet are the electrode sheets of the embodiments of the present application.

[0029] Since the current collector according to the embodiment of the present application is included, the electrode assembly has higher safety performance.

[0030] The battery cell provided in the present application includes a housing and also includes an electrode assembly according to an embodiment of the present application, wherein the electrode assembly is disposed in the housing.

[0031] Since the current collector according to the embodiment of the present application is included, the battery cell has higher safety performance.

[0032] The battery provided in the present application includes a containing box and also includes a battery cell according to an embodiment of the present application, and the battery cell is disposed in the containing box.

[0033] Since the current collector according to the embodiment of the present application is included, the battery has higher safety performance.

[0034] The electrical device provided in the present application includes the battery or battery cell of the embodiment of the present application, and the battery cell is used to provide electrical energy to the electrical device.

[0035] Since the current collector according to the embodiment of the present application is included, the safety performance of the electrical device is higher.

[0036] Based on the current collector provided in the embodiment of the present application, when a short circuit occurs during the operation of a battery cell, the support layer can be affected by the high temperature at the failure location and melt and shrink, and drive the conductive layer to shrink together, forming a hole surrounding the heated part, blocking the failed circuit and preventing the occurrence of thermal runaway. Moreover, since the conductive layer includes a granular conductive layer, the granular conductive layer is more likely to shrink along with the support layer when the support layer shrinks due to heat than other forms of conductive layers. Therefore, when a short circuit accident occurs, the circuit can be blocked more quickly and thermal runaway can be prevented more promptly, so the safety performance of the battery can be more effectively improved.

[0037] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0039] FIG1 is a simplified structural diagram of an electrical device in an embodiment of the present application.

[0040] FIG2 is a schematic diagram of an explosion of a battery in an embodiment of the present application.

[0041] FIG3 is a schematic diagram of an explosion of a battery cell in an embodiment of the present application.

[0042] FIG4 is a simplified structural diagram of the electrode assembly in an embodiment of the present application.

[0043] FIG5 is a simplified diagram of the structure of the current collector in an embodiment of the present application.

[0044] FIG6 is a schematic diagram showing the principle of preventing thermal runaway of the current collector in an embodiment of the present application.

[0045] Description of reference numerals:

[0046] 100. Electric device; 101. Vehicle; 102. Controller; 103. Power equipment; 104. Motor; 105. Main body;

[0047] 10. Battery;

[0048] 20. Battery cell; 201. Electrode assembly; 202. Housing; 203. Casing; 204. End cap; 205. Adapter; 206. Electrode terminal; 207. Tab; 208. Isolator;

[0049] 30. Container; 301. Box body; 302. Box cover;

[0050] 1. Positive electrode;

[0051] 2. Negative electrode;

[0052] 3. Diaphragm;

[0053] 4. Electrode sheet;

[0054] 5. Current collector; 51. Support layer; 511. Support film; 512. Polyethylene film; 52. Conductive layer; 521. Granular conductive layer; 522. Graphite layer; 523. Metal particle layer; 524. First conductive layer; 525. Second conductive layer; 526. Holes;

[0055] 6. Active substances;

[0056] 7. Short circuit initiator; 71. Puncture needle. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without carrying out creative work are within the scope of protection of this application.

[0058] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0059] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0060] In the description of this application, it should be understood that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0061] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0062] Batteries are increasingly used in a wide range of applications. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, the requirements for their performance are also increasing.

[0063] Safety is a key performance indicator for batteries. Thermal runaway accidents must be prevented during battery use and routine maintenance. However, how to more effectively prevent thermal runaway and improve safety performance has always been a challenge.

[0064] In order to improve the safety performance of a battery, the present application provides a current collector, an electrode assembly, a battery cell, a battery, and an electrical device.

[0065] 1-6 illustrate the structures of an electrical device, a battery, a battery cell, an electrode assembly, and a current collector in some embodiments of the present application.

[0066] Next, the present application will be described with reference to FIG1 to FIG6 .

[0067] Figure 1 illustrates the structure of an electrical device 100. Referring to Figure 1 , the electrical device 100 is a device that uses a battery cell 20 as a power source. The device includes a battery 10 or battery cell 20, which is used to provide electrical energy to the device 100. Specifically, the device 100 includes a body 105 and a battery cell 20. The battery cell 20 is mounted on the body 105 and provides electrical energy to the body 105.

[0068] The electrical device 100 may be a mobile phone, tablet, laptop computer, electric toy, electric tool, battery car, electric car, ship, spacecraft, or other electrical equipment. Electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Spacecraft may include airplanes, rockets, space shuttles, and spacecraft.

[0069] The electrical device 100 includes a power source, which includes a battery 10. The battery 10 provides driving force for the electrical device 100. In some embodiments, the driving force of the electrical device 100 is entirely electrical energy, in which case the power source only includes the battery 10. In other embodiments, the driving force of the electrical device 100 includes electrical energy and other energy sources (such as mechanical energy), in which case the power source includes the battery 10 and other equipment such as an engine.

[0070] As an example, the power-consuming device 100 is a vehicle 101. Referring to FIG1 , in some embodiments, the power-consuming device 100 is a new energy vehicle such as a pure electric vehicle, a hybrid electric vehicle, or a range-extended vehicle, and includes a battery 10, a controller 102, and a power device 103 such as a motor 104. The battery 10 is electrically connected to the power device 103 such as the motor 104 via the controller 102, so that the battery 10 can supply power to the power device 103 such as the motor 104 under the control of the controller 102.

[0071] It can be seen that the battery 10 is an important component of the electrical device 100 .

[0072] FIG2 exemplarily shows the structure of the battery 10. Referring to FIG2 , the battery 10 includes a storage box 30 and a battery cell 20 disposed in the storage box 30. The storage box 30 includes a box body 301 and a box cover 302. The box body 301 and the box cover 302 are interlocked to form a closed storage space inside the storage box 30 to accommodate the battery cell 20. The number of battery cells 20 in the storage box 30 can be at least two to provide more electrical energy and meet higher usage requirements. The battery cells 20 of the battery 10 can be electrically connected in series, parallel or mixed to achieve a larger capacity or power. It can be understood that the battery cells 20 are simplified in FIG2 .

[0073] As can be seen, the battery cell 20 is the smallest battery unit used to provide electrical energy. It is a core component of the power-consuming device 100 and the battery 10, and its performance directly affects the performance of the power-consuming device 100 and the battery 10. Improving the safety performance of the battery cell 20 is conducive to improving the performance of the power-consuming device 100 and the battery 10.

[0074] The battery cell 20 can be any type of battery cell such as a lithium-ion battery, and can be in any shape such as a square or a cylinder.

[0075] 3 exemplarily shows the structure of a battery cell 20. Referring to FIG3 , the battery cell 20 includes a housing 202, an electrode assembly 201, an adapter 205, an electrode terminal 206, and a separator 208.

[0076] The housing 202 is used to house and protect the electrode assembly 201 and other components. The housing 202 includes a shell 203 and an end cap 204. The end cap 204 covers the end opening of the shell 203, forming a sealed space within the housing 202 for housing the electrode assembly 201 and other components.

[0077] The electrode assembly 201 is used to generate electricity. It is located within the housing 202 and generates electricity through an electrochemical reaction with the electrolyte injected into the housing 202. Depending on actual usage requirements, the number of electrode assemblies 201 in a battery cell 20 can be one, two, or more. The electricity generated by the electrode assembly 201 is transmitted to the outside through the tabs 207.

[0078] Tabs 207 are the portions of the positive and negative electrode sheets of electrode assembly 201 that are not coated with active material 6. They extend outward from the portions of the positive and negative electrode sheets coated with active material 6 and are electrically connected to an external circuit via adapter 205 and electrode terminals 206 to enable outward transmission of electrical energy. The tabs 207 of the positive electrode sheet are referred to as positive tabs, while the tabs 207 of the negative electrode sheet are referred to as negative tabs.

[0079] The adapter 205 is disposed in the housing 202 and is located between the electrode tab 207 of the electrode assembly 201 and the electrode terminal 206. It is used to achieve electrical connection between the electrode assembly 201 and the electrode terminal 206, thereby transmitting the electrical energy generated by the electrode assembly 201 to the electrode terminal 206. The adapter 205 corresponding to the positive tab is called the positive adapter, and the adapter 205 corresponding to the negative tab is called the negative adapter.

[0080] The electrode terminal 206 is electrically connected to the electrode assembly 201 through the adapter 205 and is used to connect to an external circuit to transmit the electrical energy generated by the electrode assembly 201 to the outside of the battery cell 20. The electrode terminal 206 corresponding to the positive tab is called the positive terminal, and the electrode terminal 206 corresponding to the negative tab is called the negative terminal.

[0081] The isolation member 208 is disposed in the outer shell 202 and is located between the electrode assembly 201 and the shell 203 , and is used to insulate the electrode assembly 201 from the shell 203 to prevent a short circuit between the electrode assembly 201 and the shell 203 .

[0082] It can be seen that the electrode assembly 201 is an important component of the battery cell 20 and is the key to the battery cell 20 being able to provide electrical energy.

[0083] Figure 4 further illustrates the structure of electrode assembly 201. Referring to Figure 4 , electrode assembly 201 includes electrode sheets 4, and includes two types of electrode sheets 4 with opposite polarities: a positive electrode sheet 1 and a negative electrode sheet 2. The positive electrode sheet 1 and the negative electrode sheet 2 are stacked or wound together. Furthermore, a separator 3 is provided between the positive electrode sheet 1 and the negative electrode sheet 2 to separate the positive electrode sheet 1 and the negative electrode sheet 2.

[0084] As shown in Figure 4 , both the positive electrode sheet 1 and the negative electrode sheet 2 include an active material 6 and a current collector 5. The active material 6 is coated on the current collector 5 and is used to electrochemically react with the electrolyte in the housing 202 to generate electricity, enabling the charge and discharge process. As shown in Figure 4 , in some embodiments, the active material 6 is coated on both opposing surfaces of the current collector 5.

[0085] The active materials 6 on the positive electrode sheet 1 and the negative electrode sheet 2 are different, resulting in opposite polarities of the positive electrode sheet 1 and the negative electrode sheet 2. For example, in some embodiments, the active material 6 on the positive electrode sheet 1 includes LiCoO2 (lithium-containing cobalt dioxide) particles, and the active material 6 on the negative electrode sheet 2 includes SnO2 (tin dioxide) particles.

[0086] In electrode assembly 201, current collector 5 not only carries active material 6 but also collects the current generated by the electrochemical reaction, generating a larger current for external output. Current collector 5 is an integral component of battery cell 20 and a key factor affecting the operational safety of battery cell 20.

[0087] In related technologies, the current collector 5 is usually made of metal materials. For example, the current collector 5 of the positive electrode sheet 1 is usually made of aluminum foil, and the current collector 5 of the negative electrode sheet 2 is usually made of copper foil. However, the current collector 5 made of this metal material is difficult to prevent thermal runaway when a short circuit occurs in the battery cell 20, which restricts the improvement of the safety performance of the battery cell 20.

[0088] Thermal runaway of a battery cell 20 often results from a violent chemical reaction or electrochemical reaction inside the battery cell 20. When the diaphragm 3 in the battery cell 20 is damaged due to internal foreign matter (such as metal particles, burrs on the positive and negative electrodes, or metal lithium dendrites deposited during battery use) or external puncture, the positive and negative electrodes on both sides of the damaged area may be connected, resulting in a short circuit. When a short circuit occurs, the short-circuit current will cause a sharp rise in temperature, triggering a more violent reaction and spreading to other parts, causing thermal runaway, leading to fire or explosion accidents, and seriously threatening the personal safety of users.

[0089] Since metal materials have a high melting point, the metal current collector 5 is not easy to melt. As a result, when a short circuit occurs, the current collector 5 has not yet melted, and other components of the battery cell 20 (such as the active material 6 and the diaphragm 3) have already failed. In this case, the current collector 5 cannot block the current transfer and cannot prevent the occurrence of thermal runaway, thus affecting the safety performance of the battery cell 20.

[0090] In view of the above situation, the present application improves the structure of the current collector 5 to enhance the safety performance of the current collector 5 , the electrode assembly 201 , the battery cell 20 , the battery 10 and the electrical device 100 .

[0091] 5-6 exemplarily show the structure of the current collector 5 .

[0092] 5 and 6 , the current collector 5 provided in the present embodiment includes a support layer 51 and a conductive layer 52. The conductive layer 52 is disposed on at least one of two opposing sides of the support layer 51 and contracts along with the support layer 51 when heated, forming holes 526 surrounding the heated area. Furthermore, the conductive layer 52 includes a first conductive layer 524 in contact with the support layer 51. The first conductive layer 524 is a granular conductive layer 521.

[0093] It can be seen that in the embodiment of the present application, the current collector 5 is no longer a single-layer metal foil structure, but becomes at least a two-layer structure including a support layer 51 and a conductive layer 52 .

[0094] Because the support layer 51 has a low melting point, it can melt when heated, causing the conductive layer 52 to shrink, forming holes 526 around the heated area. Therefore, when a short circuit occurs during the operation of the battery cell 20, the support layer 51 can, under the action of the high temperature at the failure location, cause the conductive layer 52 to shrink, forming holes 526 around the failure location, thereby blocking the failure circuit and preventing thermal runaway. Referring to Figure 6, after the hole 526 is formed, the short circuit initiator 7 (such as the puncture needle 71, metal particles or burrs) that caused the short circuit accident is no longer surrounded by conductors. The short circuit initiator 7 can no longer contact the conductor, so the circuit is disconnected, which can prevent the positive electrode 1 and the negative electrode 2 from being connected due to damage to the diaphragm 3, and can prevent local heat from continuing to spread to other parts, thereby preventing thermal runaway.

[0095] Moreover, since in the embodiment of the present application, the first conductive layer 524 of the conductive layer 52 that contacts the support layer 51 is a granular conductive layer 521, the granular conductive layer 521 is more likely to shrink along with the support layer 51 when the support layer 51 shrinks due to heat than other forms of conductive structures. Therefore, it is convenient to block the circuit more quickly and prevent thermal runaway more promptly when a short circuit accident occurs, so that the safety performance can be improved more effectively.

[0096] It can be seen that by constructing the current collector 5 to include a support layer 51 and a conductive layer 52, and constructing the first conductive layer 524 of the conductive layer 52 that is in contact with the support layer 51 as a granular conductive layer 521, thermal runaway can be prevented more efficiently and reliably, thereby effectively improving the safety performance.

[0097] The granular conductive layer 521 may be composed of various metal or non-metal conductive particles. For example, referring to FIG5 , the granular conductive layer 521 includes a metal particle layer 523 .

[0098] Since metal has good electrical conductivity, when the granular conductive layer 521 includes the metal particle layer 523, it can effectively prevent thermal runaway while taking into account the electrical conductivity of the current collector 5, so that the current collector 5 has good electrical conductivity and can conduct electricity efficiently in normal working conditions without short circuit.

[0099] Examples of the metal particle layer 523 include a copper particle layer, an aluminum particle layer, a gold particle layer, a silver particle layer, or an alloy particle layer. Copper, aluminum, gold, silver, or alloys thereof are all metal materials with good electrical conductivity and can therefore effectively improve the electrical conductivity of the current collector 5.

[0100] In some embodiments, the resistivity of the alloy in the alloy particle layer is less than or equal to 30·10 -9Ω·m (ohm·meter), the alloy particle layer has a higher conductivity efficiency at this time, and the current collector 5 can have better conductivity.

[0101] There are many ways to combine the first conductive layer 524 with the support layer 51 . In one example, the first conductive layer 524 can be sprayed onto the support layer 51 .

[0102] The spraying method is more suitable for the granular state of the granular conductive layer 521 in the first conductive layer 524, and the granular conductive layer 521 can be easily compounded on the support layer 51. After spraying, the granular conductive layer 521 can be more firmly attached to the support layer 51. On the one hand, it is convenient for the support layer 51 to drive the granular conductive layer 521 to melt and shrink together when it is partially melted, so that the collector 5 can smoothly cut off the circuit when a short circuit accident occurs. On the other hand, it is also beneficial to prevent the granular conductive layer 521 from accidentally falling off in the non-short circuit state, so that the collector 5 can more reliably collect and transmit current during normal operation.

[0103] 5 , in some embodiments, the conductive layer 52 includes not only a first conductive layer 524 , but also a second conductive layer 525 . The second conductive layer 525 is electrically connected to the surface of the granular conductive layer 521 facing away from the support layer 51 .

[0104] Since the second conductive layer 525 can further enhance the conductivity of the conductive layer 52 , further adding the second conductive layer 525 on the basis of the first conductive layer 524 can more effectively enhance the conductivity of the current collector 5 .

[0105] The second conductive layer 525 can be bonded to the first conductive layer 524 in various ways. For example, the second conductive layer 525 can be bonded to the first conductive layer 524 using a conductive agent and an adhesive. This facilitates the connection between the first conductive layer 524 and the second conductive layer 525, ensuring a strong and secure connection. Furthermore, it facilitates electrical connection between the first conductive layer 524 and the second conductive layer 525.

[0106] Additionally, the second conductive layer 525 can have various structural forms. For example, referring to FIG5 , in some embodiments, the second conductive layer 525 includes a graphite layer 522 . Since graphite has a much higher conductivity than other non-metallic conductive materials, configuring the second conductive layer 525 to include the graphite layer 522 can more effectively improve the conductive performance of the conductive layer 52 .

[0107] In some embodiments, the conductivity of the conductive layer 52 is 10 4 ~10 5S / cm (Siemens per centimeter). In this case, the conductive layer 52 can better meet the conductivity requirements of the current collector 5 and can effectively prevent the battery cell 20 from generating excessive heat during normal charging and discharging.

[0108] In the aforementioned embodiments, the support layer 51 is used to support the conductive layer 52 and, when a short circuit accident occurs, drives the conductive layer 52 to shrink together, cuts off the failed circuit, and prevents the occurrence of thermal runaway.

[0109] The melting point of the support layer 51 may be less than or equal to 120°. Therefore, the support layer 51 is more likely to melt and shrink before other parts melt, thus cutting off the failure circuit. Therefore, thermal runaway can be more reliably prevented, and safety performance can be more effectively improved.

[0110] In some embodiments, the support layer 51 is made of a polymeric organic material such as polyethylene, polypropylene, or polyurethane. Polymers such as polyethylene, polypropylene, or polyurethane have low melting points and can rapidly shrink and collapse when locally heated. Therefore, a support layer 51 made of a polymeric organic material can quickly disconnect a failed circuit when needed, preventing thermal runaway and improving safety.

[0111] Furthermore, the support layer 51 can have various shapes, for example, granular or non-granular. For example, referring to FIG5 , the support layer 51 is in the form of a film, in which case the support layer 51 is a support film 511. The support film 511 can effectively support the conductive layer 52, thereby improving the safety performance of the current collector 5 and enhancing its structural stability.

[0112] 5 , in some embodiments, the support layer 51 is a polyethylene film 512 . In this case, the support layer 51 is a polyethylene film 511 , which can effectively prevent thermal runaway and enhance the bending resistance of the current collector 5 .

[0113] Next, the embodiment shown in FIG5 will be further described.

[0114] As shown in FIG. 5 , in this embodiment, the current collector 5 includes a support layer 51 and two conductive layers 52 . The two conductive layers 52 are disposed on opposite sides of the support layer 51 , and each conductive layer 52 includes a first conductive layer 524 and a second conductive layer 525 .

[0115] The supporting layer 51 is specifically a polyethylene film 512 , the first conductive layer 524 is specifically a metal particle layer 523 , and the second conductive layer 525 is specifically a graphite layer 522 .

[0116] The polyethylene film 512 is located in the middle. Metal particle layers 523 are sprayed onto opposite sides of the polyethylene film 512. A graphite layer 522 is bonded to the outer surface of the metal particle layer 523 on each side. The graphite layer 522 is bonded to the surface of the metal particle layer 523 facing away from the polyethylene film 512 via a conductive agent and an adhesive. The surface of the graphite layer 522 facing away from the metal particle layer 523 becomes the outer surface of the conductive layer 52, which is used to carry the active material 6. When manufacturing the electrode sheet 4, the active material 6 is coated on the outer surface of the graphite layer 522, so that the opposite sides of the current collector 5 are coated with the active material 6.

[0117] Based on the above configuration, the current collector 5 forms a five-layer structure with a polyethylene film 512 in the middle and metal particle layers 523 and graphite layers 522 symmetrically provided on both sides of the polyethylene film 512 .

[0118] The metal particle layer 523 and the graphite layer 522 mainly play a conductive role. The conductive layer 52 composed of the metal particle layer 523 and the graphite layer 522 can maintain a conductivity of 10 4 ~10 5 Within the range of S / cm (Siemens per centimeter), the conductivity requirement of the current collector 5 can be well met, and the battery cell 20 can be effectively prevented from generating excessive heat during conventional charging and discharging due to the large resistivity of the current collector 5.

[0119] The polyethylene film 512 supports the metal particle layer 523 and the graphite layer 522 , thereby enhancing the anti-bending property of the current collector 5 and improving the safety performance of the current collector 5 .

[0120] Taking the case of puncture failure shown in FIG6 as an example, how the safety performance of the current collector 5 of this embodiment is improved is explained. In FIG6 , the metal particle layer 523 is depicted in a simplified manner.

[0121] Referring to FIG6 and FIG4 , when the puncture needle 71 pierces the positive and negative electrode sheets and the diaphragm 3, the puncture needle 71 conducts the current collector 5 of the positive electrode sheet 1 and the current collector 5 of the negative electrode sheet 2, and a large current passes through the failure point, resulting in an extremely high temperature at the failure point. In this case, if the current collector 5 is a metal current collector, then since the melting point of the metal current collector is higher than that of other materials, it will cause the active material 6 or other components such as the diaphragm 3 to fail, resulting in thermal runaway. The current collector 5 of this embodiment is no longer a single-layer metal foil structure, but a five-layer structure including a polyethylene film 512, a metal particle layer 523 and a graphite layer 522, wherein the metal is used to support the metal. The part of the polyethylene film 512 of the particle layer 523 and the graphite layer 522 located around the puncture needle 71 can quickly melt and shrink during the temperature rise at the failure position, driving the metal particle layer 523 and the graphite layer 522 located on the corresponding part of the polyethylene film 512 to shrink together, so that the part of the current collector 5 located around the puncture needle 71 quickly collapses to form a hole 526. Since the formed hole 526 can cut off the electrical connection between the puncture needle 71 and the current collector 5, the failed circuit is cut off. Therefore, it can effectively prevent the further development of the electrochemical reaction and internal short circuit inside the battery and prevent thermal runaway, so it can effectively improve the safety performance.

[0122] Since the metal particle layer 523 is granular, the bonding tightness between the metal particles is relatively low compared to non-granular materials such as metal foil, and the metal particles are easily disconnected at high temperatures. Therefore, when the polyethylene film 512 melts and shrinks, the metal particle layer 523 can shrink relatively easily, making it easier for the current collector 5 to cut off the failed circuit more quickly. Therefore, it is beneficial to more reliably prevent thermal runaway, thereby more effectively improving safety performance.

[0123] The current collector 5 can be either the current collector 5 of the positive electrode sheet 1 or the current collector 5 of the negative electrode sheet 2. When the current collector 5 is the current collector 5 of the positive electrode sheet 1, the metal particle layer 523 can be an aluminum particle layer made of powdered aluminum powder. When the current collector 5 is the current collector 5 of the negative electrode sheet 2, the metal particle layer 523 can be a copper particle layer made of powdered copper powder.

[0124] The above description is merely an exemplary embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

DEPCT6626 / 07 / 25651. A current collector (5) composed of: a support layer (51); and a conductive layer (52) on at least one side of two opposite sides of the support layer (51), where, when the support layer (51) is heated and shrinks, the conductive layer (52) shrinks with the support layer (51) to form a hole (526) surrounding the heated area. The conductive layer (52) is composed of a primary conductive layer (524) in contact with the support layer (51), and the primary conductive layer (524) is a granular conductive layer. (521)2. The current collector (5) under claim 1 in which the conductive layer (52) is modified so that the granular conductive layer (521) is incorporated with a metal particle layer (523). The conductive layer (52) is incorporated with a secondary conductive layer (525) which is electrically bonded to the surface of the granular conductive layer (521) facing away from the support layer (51). The conductivity of the conductive layer (52) is 10⁴ to 10⁵ siemens / cm; and / or the primary conductive layer (524) is sprayed onto the support layer (51). 3.A current collector (5) under claim 2 in which a metal particle layer (523) is combined with a copper particle layer, an aluminum particle layer, a gold particle layer, a silver particle layer or an alloy particle layer.

4. A current collector (5) under claim 3 in which the electrical resistivity of the alloy in the alloy particle layer is less than or equal to 30-10⁻⁹ omega•m.

5. A current collector (5) under any one of claims 2 to 4 in which a secondary conductive layer (525) is bonded to a secondary conductive layer.

6. Current collector (5) under any one of the claims 1 through 5 in which the support (51) is modified so that: the melting point of the support (51) is less than or equal to 120°; the support (51) is a support film (511) and / or the support (51) is made of an organic polymer material.

7. Current collector (5) under claim 6 in which the support (51) is a polyethylene film (512). 8.

9. An electrode assembly (201) consisting of a positive electrode plate (1) and a negative electrode plate (2), where the positive electrode plate (1) and / or negative electrode plate (2) are electrode plates (4) according to claim 8.

10. A battery cell (20) consisting of a housing (202) and an additional electrode assembly (201).

11. A battery (10) assembled with a housing (30) and additionally assembled with battery cells (20) according to claim 10, battery cells (20) arranged in the housing (30).

12. An electrical device (100) assembled with a battery (10) according to claim 11 or battery cells (20) according to claim 10, battery cells (20) configured to provide power to the electrical device (100).A current collector (5) comprising: a support (51); and a conductive layer (52) on at least one side of two opposite sides of the support (51) where, when the support (51) is heated and shrinks, the conductive layer (52) shrinks with the support (51) to form a hole (526) around the heated area. The conductive layer (52) comprises a first conductive layer (524) in contact with the support (51), and the first conductive layer (524) is a granulated conductive layer (521).

2. A current collector (5) according to claim 1 in which the conductive layer (52) is shaped to The electrical conductor (5) under claim 2 is composed of a granulated electrical conductor (521) incorporating a layer of metal particles (523); the electrical conductor (52) is composed of a second electrical conductor (525) electrically bonded to the surface of the granulated electrical conductor (521) facing away from the support layer (51); the conductivity of the electrical conductor (52) is 104~105 seconds / cm; and / or the first electrical conductor (524) is sprayed onto the support layer (51).

3. The electrical conductor (5) under claim 2 in which the layer of metal particles (523) is incorporating a layer of copper particles, an aluminum particle layer, a gold particle layer, a silver particle layer, or an alloy particle layer. 4.Current collectors (5) under claim 3 where the electrical resistivity of the alloy in the alloy particle layer is less than or equal to 30-10-9 (symbol) m.

5. Current collectors (5) under any of claims 2 to 4 where a second conductive layer (525) is bonded to the first conductive layer (524); and / or the second conductive layer (525) is incorporated with a graphite layer (522).

6. Current collectors (5) under any of claims 1 to 5 where the support layer (51) is modified so that: the point of contact The liquid of the support layer (51) is less than or equal to 120 degrees; the support layer (51) is a support film (511); and / or the support layer (51) is made of organic polymer material.

7. The current collector (5) under claim 6 in which the support layer (51) is a polyethylene film (512).

8. The electrode plate (4) is assembled with active material (6) and further assembled with a current collector (5) under any one of claims 1 through 7, with active material (6) arranged on the surface of the current collector (5).9.A terminal assembly (201) consisting of: positive electrode plate (1); and negative electrode plate (2); and where the positive electrode plate (1) and / or negative electrode plate (2) are electrode plate (4) according to claim 810. A battery cell (20) consisting of a housing (202) and additionally consisting of a terminal assembly (201) according to claim 9. A terminal assembly (201) arranged in a housing (202).

11. A battery (10) consisting of a receiver box (30) and additionally consisting of a battery cell (20) according to claim 10. A battery cell (20) arranged in a receiver box (30).

12. An electrical device (100) consisting of a battery (10) according to claim 11 or a battery cell (20) according to claim 10. A battery cell (20) configured to provide power to the electrical device (100).

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