CN218548482U - Current collector, pole piece and battery - Google Patents
Current collector, pole piece and battery Download PDFInfo
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- CN218548482U CN218548482U CN202221904055.1U CN202221904055U CN218548482U CN 218548482 U CN218548482 U CN 218548482U CN 202221904055 U CN202221904055 U CN 202221904055U CN 218548482 U CN218548482 U CN 218548482U
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Abstract
The utility model discloses a mass flow body, pole piece and battery for solve the current mass flow body that has the benefit lithium function and can't improve the technical problem of battery security performance. The utility model discloses a foil layer is provided with on the foil layer and mends the lithium layer, is provided with positive temperature coefficient thermistor layer on the benefit lithium layer. In this embodiment, the ptc thermistor layer has the characteristics of low temperature small resistance and high temperature large resistance, and when the temperature exceeds a certain critical value, the resistance thereof increases rapidly. Therefore, when the temperature of the battery using the current collector exceeds the safe temperature, the resistance of the positive temperature coefficient thermistor layer is increased rapidly, the migration rate of the current and lithium ions in the battery is reduced rapidly, and the risk of thermal runaway of the battery is greatly reduced. And the positive temperature coefficient thermistor layer prevents the lithium supplement layer from being in direct contact with the positive and negative active materials, and the risk of too high reaction speed and temperature rise of lithium in the lithium supplement layer can be avoided due to the resistance characteristic of the positive temperature coefficient thermistor layer which rises along with the temperature.
Description
Technical Field
The utility model relates to a battery technology field especially relates to a mass flow body, pole piece and battery.
Background
With the rapid development of new energy automobiles, lithium ion batteries have also been paid much attention as important components. At present, the automobile industry generally requires that the lithium ion battery can simultaneously give consideration to high energy density and long cycle performance, and in order to achieve the performance goal, part of battery enterprises place the center of gravity of research and development on lithium supplement technology.
The existing lithium supplementing technology is mainly characterized in that lithium-rich oxide is added into a positive pole piece, slurry containing lithium metal particles is coated on the surface of the negative pole piece, or a lithium film and the negative pole piece are pressed into a whole to obtain the negative pole piece after lithium supplementation. The patent CN110350202A discloses a current collector, which includes a substrate layer, a lithium supplement layer on the substrate layer, and a conductive protection layer on the lithium supplement layer. Although the current collector can achieve a better lithium supplementing effect, the conductive protective layer only plays a role in sealing and protecting the lithium layer from being oxidized, the improvement on the safety performance of the battery is not large, and certain potential safety hazards exist.
Therefore, it is an important subject of research by those skilled in the art to find a current collector, a pole piece and a battery for solving the above technical problems.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model discloses mass flow body, pole piece and battery for solve the current mass flow body that has the benefit lithium function and can't improve the technical problem of battery security performance.
The embodiment of the utility model provides a mass flow body, including the foil layer, be provided with on the foil layer and mend the lithium layer, be provided with positive temperature coefficient thermistor layer on the benefit lithium layer.
Optionally, the foil layer is an aluminum foil or a copper foil.
Optionally, the lithium supplement layer is a metallic lithium layer.
Optionally, the positive temperature coefficient thermistor layer is an organic polymer coating synthesized by polyethylene and a conductive agent.
Optionally, the ptc thermistor layer is an inorganic coating of strontium titanate/barium titanate/strontium doped barium titanate/tantalum doped barium titanate.
Optionally, the thickness of the foil layer is 4 to 20 μm.
Optionally, the thickness of the lithium supplement layer is 20-30 μm.
Optionally, the thickness of the positive temperature coefficient thermistor layer is 5 to 20 μm.
The embodiment of the utility model provides a pole piece, including foretell mass flow body.
The embodiment of the utility model provides a battery, including foretell pole piece.
According to the technical solution provided by the utility model, the embodiment of the utility model has the following advantage:
in this embodiment, the ptc thermistor layer has the characteristics of low temperature small resistance and high temperature large resistance, and when the temperature exceeds a certain critical value, the resistance thereof increases rapidly. Therefore, when the temperature of the battery using the current collector exceeds the safe temperature, the resistance of the positive temperature coefficient thermistor layer is increased rapidly, the migration rate of the current and lithium ions in the battery is reduced rapidly, and the risk of thermal runaway of the battery is greatly reduced. And the positive temperature coefficient thermistor layer prevents the lithium supplement layer from being in direct contact with the positive and negative active materials, and the resistance characteristic of the positive temperature coefficient thermistor layer rising along with the temperature can prevent the risks of too high reaction speed and too high temperature rise of lithium in the lithium supplement layer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a current collector provided in an embodiment of the present invention;
illustration of the drawings: a foil layer 1; a lithium supplement layer 2; a positive temperature coefficient thermistor layer 3.
Detailed Description
The embodiment of the utility model discloses mass flow body, pole piece and battery for solve the current mass flow body that has the benefit lithium function and can't improve the technical problem of battery security performance.
In order to make the technical field better understand the solution of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings and the detailed description. It is to be understood that the disclosed embodiments are merely exemplary of the invention, and are not intended to limit the invention to the precise embodiments disclosed. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Example one
Referring to fig. 1, a current collector provided in the present embodiment includes:
the lithium ion battery comprises a foil layer, wherein a lithium supplement layer is arranged on the foil layer, and a positive temperature coefficient thermistor layer is arranged on the lithium supplement layer.
In the embodiment, the foil layer is used as a matrix and provides the functions of supporting and collecting current; the lithium supplement layer provides a lithium source to provide additional lithium for the battery so as to supplement the consumption of the lithium of the SEI film of the negative electrode during the first charging of the battery and the loss of lithium ions in the cycle, thereby improving the first effect, the capacity and the cycle life of the battery; the positive temperature coefficient thermistor layer can isolate air from contacting with the lithium supplement layer, protects the lithium supplement layer from being oxidized, and facilitates the transportation of a current collector and the manufacturing and processing of a battery. The positive temperature coefficient thermistor layer has the characteristics of low temperature small resistance and high temperature large resistance, and when the temperature exceeds a certain critical value, the resistance of the thermistor layer is rapidly increased. Therefore, in the battery using the current collector, when the temperature exceeds the safety temperature, the resistance of the positive temperature coefficient thermistor layer is increased rapidly, the migration rate of the current and lithium ions in the battery is reduced rapidly, and the risk of thermal runaway of the battery is greatly reduced. And the positive temperature coefficient thermistor layer prevents the lithium supplement layer from being in direct contact with the positive and negative active materials, and the risk of too high reaction speed and temperature rise of lithium in the lithium supplement layer can be avoided due to the resistance characteristic of the positive temperature coefficient thermistor layer which rises along with the temperature.
Further, the foil layer in this embodiment is an aluminum foil or a copper foil.
The foil layer of this embodiment can adopt aluminium foil or copper foil or have the aluminium foil of trompil or have the copper foil of trompil or the compound foil that is formed by two or more kinds of material complex, and the designer can select the foil layer of suitable material according to actual conditions for use, and this embodiment does not do the restriction to this.
Further, the thickness of the foil layer in this embodiment is 4 to 20 μm, and a designer can select a foil layer with a suitable thickness according to actual conditions.
Further, the lithium supplement layer in this embodiment is a metal lithium layer.
Specifically, the lithium metal layer may include a binder and a conductive agent in addition to the main lithium powder material, and the designer may select the material as desired. In addition, the metal lithium layer can be coated on the surface of the foil layer in the modes of spraying, gravure coating, electrodeposition, vapor deposition and the like, and the lithium supplement amount is controlled by controlling the thickness or the surface density of the lithium supplement layer so as to meet the lithium supplement effect of different batteries.
Further, the thickness of the lithium supplement layer in the embodiment is 20 to 30 μm, and a designer can select a lithium supplement layer with a suitable thickness according to actual conditions.
Further, the ptc thermistor layer in this embodiment is an organic polymer coating layer synthesized from polyethylene and a conductive agent.
In addition, the ptc thermistor layer in this embodiment may also be an inorganic coating of strontium titanate/barium titanate/strontium-doped barium titanate/tantalum-doped barium titanate/barium titanate-doped strontium oxide.
It should be noted that the ptc thermistor layer in this embodiment may further include an adhesive, a conductive agent, and the like in addition to the ptc thermistor material that must be provided, and the designer may select the ptc thermistor layer according to actual needs.
Furthermore, the thickness of the positive temperature coefficient thermistor layer in the embodiment is 5 to 20 μm, if the positive temperature coefficient thermistor layer is too thin, the effect of the positive temperature coefficient thermistor layer is not ideal, and if the positive temperature coefficient thermistor layer is too thick, the thickness and the weight of the current collector are increased, and the energy density of the battery is reduced. In actual use, a designer can select a proper thickness according to the material selection of the positive temperature coefficient thermistor material, the coating capability, the battery energy density design and the like.
It should be noted that the ptc thermistor layer in this embodiment may be coated on the lithium supplement layer by spraying or gravure coating.
Further, after the current collector in this embodiment is rolled into a pole piece, the thicknesses of the lithium supplement layer and the positive temperature coefficient thermistor layer are compressed to a certain extent, and the compression ratio is 15% -95%; the coating material, the coating mode and the coating thickness are different, and the compression ratio is different.
Example two
Referring to fig. 1, a pole piece provided in the present embodiment includes a current collector in the first embodiment.
Specifically, the pole piece in this embodiment may be a positive pole piece or a negative pole piece, and when the pole piece is the positive pole piece, the surface of the positive temperature coefficient thermistor layer of the current collector is coated with a positive active material coating; when the pole piece is a negative pole piece, the surface of the positive temperature coefficient thermistor layer of the current collector is coated with a negative active material coating.
The positive temperature coefficient thermistor layer is arranged on the current collector of the pole piece in the embodiment, the positive temperature coefficient thermistor layer has the characteristics of low-temperature small resistance and high-temperature large resistance, and when the temperature exceeds a certain critical value, the resistance of the positive temperature coefficient thermistor layer is rapidly increased. Therefore, when the temperature of the battery using the current collector exceeds the safe temperature, the resistance of the positive temperature coefficient thermistor layer is increased rapidly, the migration rate of the current and lithium ions in the battery is reduced rapidly, and the risk of thermal runaway of the battery is greatly reduced. And the positive temperature coefficient thermistor layer prevents the lithium supplement layer from being in direct contact with the positive and negative active materials, and the risk of too high reaction speed and temperature rise of lithium in the lithium supplement layer can be avoided due to the resistance characteristic of the positive temperature coefficient thermistor layer which rises along with the temperature.
EXAMPLE III
Referring to fig. 1, a battery provided in the present embodiment includes a pole piece in the first embodiment.
Specifically, the battery in the embodiment comprises a positive pole piece, an isolation film and a negative pole piece, and the current collector containing the positive temperature coefficient thermistor layer is introduced into the pole piece of the battery, so that the safety performance of the battery can be effectively improved, and the potential safety hazard of the battery can be effectively reduced.
Examples of the experiments
In order to show the safety performance of the battery to which the current collector in the first embodiment is applied, the present experimental example will be proved through specific tests, specifically, the test process is as follows:
preparing a foil:
1. comparative example: the foil layer adopts 6 mu m copper foil, and the surface is not coated;
2. experimental example 1: the foil layer adopts 6 μm copper foil; the lithium supplementing layer is formed by spraying slurry (with the solid content of 40%) containing metal lithium powder, a conductive agent and a binder (the mass ratio of the three substances is 50; the positive temperature coefficient thermistor layer is formed by spraying slurry (solid content is 65%) containing barium titanate doped strontium oxide BaTi0.93Sr0.07O3, a conductive agent and a binder (the mass ratio of the three substances is 90;
3. experimental example 2: the foil layer adopts 6 μm copper foil; the materials and coating modes of the lithium supplement layer and the positive temperature coefficient thermistor layer are the same as those of experimental example 1, wherein the thickness of the lithium supplement layer is 25 micrometers, and the thickness of the positive temperature coefficient thermistor layer is 12 micrometers;
4. experimental example 3: the foil material adopts 6 μm copper foil; the materials and coating modes of the lithium supplement layer and the positive temperature coefficient thermistor layer are the same as those of experimental example 1, wherein the thickness of the lithium supplement layer is 30 micrometers, and the thickness of the positive temperature coefficient thermistor layer is 12 micrometers;
5. experimental example 4: the foil layer adopts 6 μm copper foil; the materials and coating modes of the lithium supplement layer and the positive temperature coefficient thermistor layer are the same as those of experimental example 1, wherein the thickness of the lithium supplement layer is 25 micrometers, and the thickness of the positive temperature coefficient thermistor layer is 20 micrometers;
6. experimental example 5: the foil layer adopts 6 μm copper foil; the materials and coating modes of the lithium supplement layer and the positive temperature coefficient thermistor layer are the same as those of experimental example 1, wherein the thickness of the lithium supplement layer is 25 micrometers, and the thickness of the positive temperature coefficient thermistor layer is 5 micrometers;
7. experimental example 6: the foil layer adopts 6 μm copper foil; the materials and coating modes of the lithium supplement layer and the positive temperature coefficient thermistor layer are the same as those of experimental example 1, wherein the thickness of the lithium supplement layer is 25 micrometers, and the thickness of the positive temperature coefficient thermistor layer is 2 micrometers;
preparing a battery: the foils of the comparative example and the examples 1 to 6 are respectively adopted to manufacture a negative plate and a positive plate, wherein the negative active material is a silicon-carbon material (the mass ratio of silicon-carbon, a conductive agent and a binder is 96; the positive electrode sheet active material is a ternary material (the mass ratio of the NCM, the conductive agent and the binder is 97; the diaphragm is a PE diaphragm with the thickness of 9 mu m; the electrolyte is formed by mixing 1mol/L LiPF6 and EC/DMC/EMC (V/V = 1.
Testing of the battery:
capacity and first effect: standing the battery for 12h at 45 ℃ after liquid injection, then charging to 3.40V at 0.02C, charging to 3.75V at 0.1C, discharging for two times, then charging to 4.35V at 0.5C with constant current and constant voltage, stopping at 0.05C, and then discharging to 2.8V at 0.5C to obtain discharge capacity; the first effect is the total charge capacity in the first discharge capacity ratio;
DCR: the cell was adjusted to 50% SOC at 25 ℃, discharged at 2C for 30s, and the DCR value was calculated using the voltage difference between the open circuit voltage before discharge and the 30s discharge as the discharge current;
and (3) circulation: charging to 4.35V at 25 deg.C under constant current and constant voltage at 1C, stopping at 0.05C, standing for 30min, discharging to 2.8V at 1C, and standing for 30min. And repeating the steps.
And (4) safety testing: and (4) carrying out testing on overcharge, needling and short circuit according to the GB/T31485-2015 standard.
The first effect, capacity, DCR, cycle and safety test results are as follows:
the comparative example has no coating, and has low first effect, low capacity, poor cycle life and poor safety performance; in experimental examples 1 to 6, after the lithium supplement layer and the positive temperature coefficient thermistor layer are added, the first effect, capacity, cycle life and safety performance are greatly improved, and the DCR is slightly increased. In experimental examples 1 to 3, the thickness of the lithium supplement layer is sequentially increased, the lithium supplement amount is sequentially increased, and when the thickness of the lithium supplement layer is larger than 25um, the first effect and the capacity are not obviously improved, the cycle is slightly reduced, and the lithium supplement amount may be too much and exceeds the requirement of the battery. Compared with the experimental example 2, the positive temperature coefficient thermistor layer of the experimental example 4 is thicker, the safety performance is better, but the increase ratio of DCR is larger; the positive temperature coefficient thermistor layer of experimental example 5 is thin, the DCR gain ratio is slightly small, but the safety performance is poor; the ptc thermistor layer of experimental example 6 is too thin to be within the scope of the patent claims, and the improvement in safety is small compared to the comparative example. Comprehensive evaluation is carried out, and the experimental example 2 is better.
It is right above the utility model provides a mass flow body, pole piece and battery have carried out detailed introduction, to the general technical personnel in this field, the foundation the utility model discloses the thought of embodiment all has the change part on concrete implementation and application scope, to sum up, this specification content should not be understood as right the utility model discloses a restriction.
Claims (8)
1. The current collector is characterized by comprising a foil layer, wherein a lithium supplement layer is arranged on the foil layer, and a positive temperature coefficient thermistor layer is arranged on the lithium supplement layer;
the positive temperature coefficient thermistor layer is a conductive polyethylene coating or a strontium titanate coating or a barium titanate coating or a strontium-doped barium titanate coating or a tantalum-doped barium titanate coating.
2. The current collector of claim 1, wherein the foil layer is an aluminum foil or a copper foil.
3. The current collector of claim 1, wherein the lithium supplement layer is a metallic lithium layer.
4. The current collector of claim 1, wherein the thickness of the foil layer is between 4 and 20 μ ι η.
5. The current collector of claim 1, wherein the lithium supplement layer has a thickness of 20 to 30 μ ι η.
6. The current collector of claim 1, wherein the thickness of the positive temperature coefficient thermistor layer is 5-20 μm.
7. A pole piece, comprising a current collector as claimed in any one of claims 1 to 6.
8. A battery comprising a pole piece according to claim 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221904055.1U CN218548482U (en) | 2022-07-22 | 2022-07-22 | Current collector, pole piece and battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221904055.1U CN218548482U (en) | 2022-07-22 | 2022-07-22 | Current collector, pole piece and battery |
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| Publication Number | Publication Date |
|---|---|
| CN218548482U true CN218548482U (en) | 2023-02-28 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202221904055.1U Active CN218548482U (en) | 2022-07-22 | 2022-07-22 | Current collector, pole piece and battery |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
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| TR01 | Transfer of patent right |
Effective date of registration: 20240307 Address after: 215500 No. 68, Xin'anjiang Road, Southeast street, Changshu, Suzhou, Jiangsu Patentee after: Jiangsu Zenergy Battery Technologies Co.,ltd Country or region after: China Address before: No. 1 Jiayuan Road, Dalang Town, Dongguan City, Guangdong Province, 523000 Patentee before: Dongguan Zhengli New Energy Battery Technology Co.,Ltd. Country or region before: China |
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Address after: 215500 No. 68, Xin'anjiang Road, Southeast street, Changshu, Suzhou, Jiangsu Patentee after: Jiangsu Zhengli New Energy Battery Technology Co.,Ltd. Country or region after: China Address before: 215500 No. 68, Xin'anjiang Road, Southeast street, Changshu, Suzhou, Jiangsu Patentee before: Jiangsu Zenergy Battery Technologies Co.,ltd Country or region before: China |