Search

CN-122025804-A - Battery cell, method for producing secondary battery, electrolyte and electricity-using device

CN122025804ACN 122025804 ACN122025804 ACN 122025804ACN-122025804-A

Abstract

The application relates to the technical field of batteries, in particular to a preparation method of a battery monomer and a secondary battery, an electrolyte and an electric device. The battery monomer comprises a positive electrode plate, a negative electrode plate and electrolyte, wherein at least part of structures of the positive electrode plate and the negative electrode plate are positioned in the electrolyte, the electrolyte comprises a metal ion complexing agent, the metal ion complexing agent comprises an organic complexing agent and/or an inorganic complexing agent, the organic complexing agent comprises at least one of phenanthroline, crown ether compound, oxalic acid, citric acid, tartaric acid, ethylenediamine tetraacetic acid and deferoxamine, and/or the inorganic complexing agent comprises at least one of oxalic acid sodium salt, sodium citrate salt, tartaric acid sodium salt and ethylenediamine tetraacetic acid sodium salt. The metal ion complexing agent in the electrolyte can be combined with impurity metal ions in the electrolyte to form a stable complex, so that the risk of self-discharge of the battery caused by that the impurity metal ions are separated out as dendritic metal foreign matters penetrating through the diaphragm at the anode is reduced.

Inventors

  • LEI DA
  • SUN JIE

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (13)

  1. 1. A battery cell is characterized by comprising a positive electrode plate, a negative electrode plate and electrolyte, wherein at least part of structures of the positive electrode plate and the negative electrode plate are positioned in the electrolyte, the electrolyte comprises a metal ion complexing agent, The metal ion complexing agent comprises an organic complexing agent and/or an inorganic complexing agent; The organic complexing agent comprises at least one of phenanthroline, crown ether compound, oxalic acid, citric acid, tartaric acid, ethylenediamine tetraacetic acid and deferoxamine; And/or the inorganic complexing agent comprises at least one of oxalic acid sodium salt, sodium citrate salt, tartaric acid sodium salt and ethylenediamine tetraacetic acid sodium salt.
  2. 2. The battery cell of claim 1, wherein the metal ion complexing agent comprises 0.01% to 1% by mass of the total electrolyte mass.
  3. 3. The battery cell of claim 1 or 2, the crown ether compound comprising at least one of 18-crown ether-6, benzo-18-crown ether-6, dibenzo-18-crown ether-6, 12-crown ether-4, aza-12-crown ether-4, 15-crown ether-5.
  4. 4. A battery cell as claimed in any one of claims 1 to 3, wherein the battery cell comprises a positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer provided on at least one side of the positive electrode current collector, the thickness of the positive electrode film layer on the one side being 0.01mm to 0.07mm.
  5. 5. The battery cell of any one of claims 1 to 4, wherein the battery cell has a power density of 2000W/kg to 20000W/kg.
  6. 6. A method for preparing a secondary battery is characterized by comprising the step of injecting electrolyte into the secondary battery, wherein the electrolyte comprises a metal ion complexing agent.
  7. 7. The method for manufacturing a secondary battery according to claim 6, wherein the step of injecting the electrolyte into the secondary battery comprises: injecting a first electrolyte into the battery to obtain a first electrolyte injection battery; Injecting a second electrolyte into the first electrolyte injection battery to obtain a second electrolyte injection battery; the first electrolyte includes the metal ion complexing agent and/or the second electrolyte includes the metal ion complexing agent.
  8. 8. The method for manufacturing a secondary battery according to claim 6 or 7, wherein the mass of the metal ion complexing agent is 0.05 to 1% by mass of the total mass of the electrolyte; And/or the metal ion complexing agent comprises an organic complexing agent and/or an inorganic complexing agent.
  9. 9. The method for manufacturing a secondary battery according to claim 7 or 8, wherein the mass percentage of the metal complexing agent in the first electrolyte to the total mass of the first electrolyte is w1, the mass percentage of the metal complexing agent in the second electrolyte to the total mass of the second electrolyte is w2, and w1< w2; The mass of the first electrolyte is greater than the mass of the second electrolyte.
  10. 10. The method for producing a secondary battery according to any one of claims 7 to 9, wherein the mass percentage of the metal complexing agent in the first electrolyte based on the total mass of the first electrolyte is w1, satisfying 0.05% +.w1+≤0.1%; And/or, the mass percentage of the metal complexing agent in the second electrolyte accounting for the total mass of the second electrolyte is w2, and the w2 is more than or equal to 0.5% and less than or equal to 1%.
  11. 11. An electrolyte, characterized in that the electrolyte comprises a metal ion complexing agent, The metal ion complexing agent comprises an organic complexing agent and/or an inorganic complexing agent; The organic complexing agent comprises at least one of phenanthroline, crown ether compound, oxalic acid, citric acid, tartaric acid, ethylenediamine tetraacetic acid and deferoxamine; And/or the inorganic complexing agent comprises at least one of oxalic acid sodium salt, sodium citrate salt, tartaric acid sodium salt and ethylenediamine tetraacetic acid sodium salt.
  12. 12. The electrolyte of claim 11, wherein the metal ion complexing agent comprises 0.05% to 1% by mass of the total mass of the electrolyte.
  13. 13. An electrical device, characterized in that it comprises a battery cell according to any one of claims 1 to 5.

Description

Battery cell, method for producing secondary battery, electrolyte and electricity-using device Technical Field The invention relates to the technical field of batteries, in particular to a preparation method of a battery monomer and a secondary battery, an electrolyte and an electric device. Background Batteries, such as lithium ion batteries, have been paid attention to because of their high specific energy, long cycle life, less self-discharge, good safety, etc., and currently, lithium ion battery applications have been extended to aspects of daily life, such as cameras, notebook computers, electric vehicles, etc. With the rapid growth of portable electronic devices, electric vehicles, etc., the demand for power batteries is also increasing. Among them, electrochemical performance of the battery is also receiving increasing attention. The self-discharge phenomenon of a battery refers to a phenomenon in which internal chemical energy is spontaneously converted into electric energy and gradually lost when the battery is not connected to an external circuit. Self-discharge can reduce the available power of the battery, resulting in a voltage drop, affecting the normal use of the device. Disclosure of Invention The application mainly aims to provide a battery monomer, a preparation method of a secondary battery, electrolyte and an electric device, and aims to reduce the self-discharge risk of the battery. In order to achieve the above object, the present application provides a battery comprising a positive electrode sheet, a negative electrode sheet and an electrolyte, at least part of structures of the positive electrode sheet and the negative electrode sheet being located in the electrolyte, the electrolyte comprising a metal ion complexing agent, The metal ion complexing agent comprises an organic complexing agent and/or an inorganic complexing agent; The organic complexing agent comprises at least one of phenanthroline, crown ether compound, oxalic acid, citric acid, tartaric acid, ethylenediamine tetraacetic acid and deferoxamine; And/or the inorganic complexing agent comprises at least one of oxalic acid sodium salt, sodium citrate salt, tartaric acid sodium salt and ethylenediamine tetraacetic acid sodium salt. The metal ion complexing agent in the electrolyte can be combined with impurity metal ions in the electrolyte to form a stable complex, so that the risk of self-discharge of the battery caused by that the impurity metal ions are separated out as dendritic metal foreign matters penetrating through the diaphragm at the anode is reduced. It will be appreciated that there is inevitably a small amount of metal impurities introduced during cell production, which, if at the cathode site, undergo electrochemical oxidation at high potential to dissolve as impurity metal ions (e.g. Fe 2+/Cr2+/Cu2+), then diffuse across the membrane to the anode surface and precipitate as dendritic metal impurities at low potential at the anode. The metal complexing agent can be combined with impurity metal ions in the electrolyte to form a stable complex, so that the impurity metal ions lose electrochemical activity, and the risk of precipitation on the surface of the anode is reduced. The metal ion complexing agent in the present application comprises an organic complexing agent and/or an inorganic complexing agent. That is, the metal ion complexing agent comprises an organic complexing agent, or the metal ion complexing agent comprises an inorganic complexing agent, or the metal ion complexing agent comprises an organic complexing agent and an inorganic complexing agent. The organic complexing agent comprises at least one of phenanthroline, crown ether compound, oxalic acid, citric acid, tartaric acid, ethylenediamine tetraacetic acid and deferoxamine. That is, the organic complexing agent comprises any of the above, or the organic complexing agent comprises a combination of the above. The inorganic complexing agent comprises at least one of oxalic acid sodium salt, sodium citrate salt, tartaric acid sodium salt and ethylenediamine tetraacetic acid sodium salt. That is, the inorganic complexing agent includes any of the above, or the inorganic complexing agent includes a combination of the above. Optionally, the mass of the metal ion complexing agent accounts for 0.01 to 1 percent of the total mass of the electrolyte. According to the application, the mass percentage of the metal ion complexing agent in the electrolyte in the battery accounts for the total mass of the electrolyte, so that the metal ion complexing agent can effectively complex impurity metal ions, and the risk of self-discharge of the battery caused by that the metal ion is separated out as dendritic metal foreign matters at the anode and pierces the diaphragm is reduced. It will be appreciated that the metal ion complexing agent in the electrolyte of the battery is gradually consumed, i.e. the amount of the metal ion complexing agent is gradually reduce