An energy storage system based on a polymer collector with controllable conductivity and its preparation process

Abstract

The invention discloses an ETP energy storage system based on a polymer collector with controllable conductivity. The inner surface is respectively provided with a positive electrode active material layer and a negative electrode active material layer, and the opposite polarity of the active material coated on the opposite surface of two adjacent electrode sheets, the inside of the electrode sheet is filled with a liquid or solid electrolyte, and the current collector is a polymeric collection of fluids. The present invention combines the electronic conductivity design of the current collector to carry out a design with an active safety function, which eliminates the out-of-control performance of the lithium ion electrochemical behavior caused by the short circuit of the battery, avoids the disadvantages of fire and explosion, and realizes the purpose of a high-safety battery.

Description

technical field [0001] The invention belongs to the technical field of energy storage systems, and in particular relates to an ETP energy storage system based on a polymer collector with controllable conductivity. Background technique [0002] Lithium-ion batteries have the advantage of high energy density, so they are widely used in modern life, but the current lithium-ion batteries still cannot meet the needs of users for longer standby time. Therefore, the development of battery products with higher energy density has become urgent needs of the industry. [0003] As the battery with the highest energy density in theory, solid-state lithium-ion battery has good application prospects, but the current solid-state lithium-ion battery usually uses metal as the current collector, which has many technical problems in practical applications, such as using aluminum or copper as the current collector. Fluid, once the internal short circuit occurs in the battery, the local current ...

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Problems solved by technology

[0002] Lithium-ion batteries have the advantage of high energy density, so they are widely used in modern life, but the current lithium-ion batteries still cannot meet the needs of users for longer standby time. Therefore, the development of battery products with higher energy density has become Urgent needs of the industry

[0003] As the battery with the highest energy density in theory, solid-state lithium-ion battery has good application prospects, but the current solid-state lithium-ion battery usually uses metal as the current collector, which has many technical problems in practical applications, such as using aluminum or copper as the current collector. Fluid, once the internal short circuit occurs in the battery, the local current density will increase, and the entire battery will discharge through the short circuit point, resulting in a stronger tendency of dendrite growth in these areas, and a large amount of energy will be released through the short circuit point in a short period of time (there will be at most 70% of the energy is released within 60s), causing a rapid rise in temperature, resulting in the decomposition of the positive and negative active materials and the combustion of the electrolyte, and in severe cases, it will cause the battery to catch fire and explode

[0004] The reason for the above situation is that when a short circuit occurs (or acupuncture simulates short circuit aging), the high electronic conductivity of the metal of the aluminum or copper current collector makes the electrons flow quickly and instantaneously, and the lithium ion flow immediately flows at the short circuit point with a huge current. Density is used to intercalate and extract lithium ions. Taking graphite as an example for the negative electrode, the lithium dendrite problem will occur when the lithium ion is released extremely fast, and the crystal structure will be destroyed if there is no rapid ion transfer in the positive electrode. The above will aggravate the failure of the battery cell body, and then appear Thermal runaway and spontaneous combustion explosion phenomena

[0005] At the same time, the volume resistivity of metal current collectors such as aluminum foil is 2.85*10 -8 Ωcm, the volume resistivity of the conductive primer layer is generally 1---5Ωcm, the volume resistivity of the active material layer of the positive electrode is generally 20Ωcm, and the volume internal resistivity of the aluminum foil metal current collector is much lower than that of the active material layer 9 From a safety point of view, when a short circuit occurs, the excellent conductivity of the aluminum foil substrate of the negative electrode will cause electrons to flow to the short circuit point instantly, and the energy will be applied to the short circuit point very quickly, resulting in uneven local deposition of lithium ions. That is, the uncontrolled deintercalation process of lithium ions occurs, resulting in the phenomenon of lithium dendrites, causing thermal runaway, resulting in explosion or spontaneous combustion

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