US-12626960-B2 - Secondary battery and preparation method thereof, battery module, battery pack, and electric apparatus

US12626960B2US 12626960 B2US12626960 B2US 12626960B2US-12626960-B2

Abstract

A secondary battery is provided, including a positive electrode plate and a negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode film layer provided on two surfaces of the positive electrode current collector, the negative electrode plate includes a negative electrode current collector and a negative electrode film layer provided on two surfaces of the negative electrode current collector, and the negative electrode film layer includes a reaction zone opposite the positive electrode film layer and a non-reaction zone not opposite the positive electrode film layer, where a lithium supplement layer and a barrier layer are provided on the non-reaction zone. A preparation method of secondary battery, a battery module, a battery pack, and an electric apparatus are also provided.

Inventors

Qingwei Yan
XIAOBIN DONG
Jiazheng WANG

Assignees

CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

Dates

Publication Date: 20260512
Application Date: 20240109

Claims (15)

1 . A secondary battery, comprising a positive electrode plate and a negative electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer provided on two surfaces of the positive electrode current collector, the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer provided on two surfaces of the negative electrode current collector, and the negative electrode film layer comprises a reaction zone opposite the positive electrode film layer and a non-reaction zone not opposite the positive electrode film layer, wherein a lithium supplement layer and a barrier layer are provided on the non-reaction zone, the lithium supplement layer is provided at an end of the non-reaction zone closer to the reaction zone, and the barrier layer is provided starting from the lithium supplement layer and extending away from the reaction zone.
2 . The secondary battery according to claim 1 , wherein distance between a side of the lithium supplement layer closer to the reaction zone and the reaction zone is 2 mm to 5 mm.
3 . The secondary battery according to claim 1 , wherein the lithium supplement layer comprises a substance capable of providing active lithium.
4 . The secondary battery according to claim 1 , wherein a theoretical capacity of lithium in the lithium supplement layer, C Li , satisfies 20% C 1 ≤C Li ≤120% C 1 , where C 1 is the capacity of the negative electrode film layer corresponding to the lithium supplement layer.
5 . The secondary battery according to claim 1 , wherein the barrier layer is selected from a film or coating incapable of being infiltrated by electrolyte; the film comprises one or more of polypropylene, polyethylene, polyester fiber, and polyvinyl chloride, the coating comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyamide, polyimide, polymethyl methacrylate, polyurethane, polystyrene, polyacrylic acid, polyacrylamide, polyacrylonitrile, and a copolymer thereof.
6 . The secondary battery according to claim 5 , wherein the film is adhesive and has an adhesion of greater than 20 N/m.
7 . The secondary battery according to claim 1 , wherein thickness of the barrier layer is 6 μm to 40 μm.
8 . The secondary battery according to claim 1 , wherein a spacing zone is provided along a width direction of the negative electrode plate at a side of the lithium supplement layer on the negative electrode plate away from the reaction zone, and the barrier layer is provided starting from the spacing zone and extending away from the reaction zone.
9 . The secondary battery according to claim 8 , wherein width of the spacing zone is 5 mm to 50 mm.
10 . The secondary battery according to claim 8 , wherein depth of the spacing zone is equal to thickness of the negative electrode film layer.
11 . A battery module, comprising the secondary battery according to claim 1 .
12 . A battery pack, comprising the battery module according to claim 11 .
13 . An electric apparatus, comprising the secondary battery according to claim 1 .
14 . A preparation method of secondary battery, comprising the following: (1) preparing a positive electrode plate; (2) preparing a negative electrode plate; (3) preparing a separator; (4) preparing an electrolyte; and (5) preparing a secondary battery; wherein step (2) comprises a step of providing a lithium supplement layer and a barrier layer on the negative electrode plate; and the secondary battery comprises a positive electrode plate and a negative electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer provided on two surfaces of the positive electrode current collector, the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer provided on two surfaces of the negative electrode current collector, and the negative electrode film layer comprises a reaction zone opposite the positive electrode film layer and a non-reaction zone not opposite the positive electrode film layer, wherein a lithium supplement layer and a barrier layer are provided on the non-reaction zone, the lithium supplement layer is provided at an end of the non-reaction zone closer to the reaction zone, and the barrier layer is provided starting from the lithium supplement layer and extending away from the reaction zone.
15 . The method according to claim 14 , wherein the barrier layer is provided through a coating or adhesive process.

Description

CROSS REFERENCE TO RELATED MATTER This application is a continuation of international application PCT/CN2022/092737, filed May 13, 2022 and entitled “SECONDARY BATTERY AND PREPARATION METHOD THEREOF, BATTERY MODULE, BATTERY PACK, AND ELECTRIC APPARATUS”, the entire content of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD This application relates to the field of lithium battery technologies, and in particular, to a secondary battery and a preparation method thereof, a battery module, a battery pack, and an electric apparatus. BACKGROUND In recent years, with increasingly wide use of lithium-ion batteries, lithium-ion batteries have been widely used in energy storage power supply systems such as hydroelectric, thermal, wind, and solar power plants, and many other fields including electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. Along with the great development of lithium-ion batteries, higher requirements are imposed on their energy density, cycling performance, safety performance, and the like. When the battery starts charging, lithium ions from the positive electrode plate preferentially intercalate into the reaction zone of the negative electrode plate, causing a decrease in the potential of the reaction zone and creating a voltage difference with the non-reaction zone. The lithium ions in the reaction zone diffuse and intercalate into the non-reaction zone at a slow speed, while the lithium ions intercalated in the non-reaction zone can hardly return to the positive electrode plate during the discharge process. This results in irreversible lithium loss in the positive electrode plate, deteriorating the initial coulombic efficiency, cycling performance, and storage performance of the battery cell. Therefore, existing lithium-ion batteries still need to be improved in terms of initial coulombic efficiency, cycling performance, and storage performance. SUMMARY This application has been made in view of the foregoing issues. An objective of this application is to provide a secondary battery which has improved initial coulombic efficiency, cycling performance, and storage performance. To achieve the foregoing objective, this application provides a secondary battery and a preparation method thereof, a battery module, a battery pack, and an electric apparatus. A first aspect of this application provides a secondary battery including a positive electrode plate and a negative electrode plate, where the positive electrode plate includes a positive electrode current collector and a positive electrode film layer provided on two surfaces of the positive electrode current collector, the negative electrode plate includes a negative electrode current collector and a negative electrode film layer provided on two surfaces of the negative electrode current collector, and the negative electrode film layer includes a reaction zone opposite the positive electrode film layer and a non-reaction zone not opposite the positive electrode film layer, where a lithium supplement layer and a barrier layer are provided on the non-reaction zone. In this application, a lithium supplement layer and a barrier layer are provided on the non-reaction zone of the negative electrode plate. The lithium supplement layer effectively prevents the lithium ions in the reaction zone from diffusing and intercalating into the non-reaction zone, while the lithium in the lithium supplement layer diffuses toward the reaction zone at a slow speed during the discharge process of the battery cell. The barrier layer fully isolates the non-reaction zone outside the lithium supplement layer, and the electrolyte cannot infiltrate the non-reaction zone, blocking the path of diffusion of lithium in the reaction zone and the lithium supplement layer to the non-reaction zone. This reduces the loss of the lithium source and further improves the initial coulombic efficiency, cycling performance, and storage performance of the secondary battery. In any embodiment, the lithium supplement layer is provided at an end of the non-reaction zone closer to the reaction zone, and the barrier layer is provided starting from the lithium supplement layer and extending away from the reaction zone. Thus, the lithium supplement efficiency can be improved without affecting the production capacity. In any embodiment, the distance between the side of the lithium supplement layer closer to the reaction zone and the reaction zone is 2 mm to 5 mm. When the distance between the side of the lithium supplement layer closer to the reaction zone and the reaction zone is in the specified range, the initial coulombic efficiency and cycling performance of the secondary battery can be further improved. In any embodiment, the lithium supplement layer includes a substance capable of providing active lithium; optionally includes one or more of lithium metal foil, lithium powder, and lithium alloy; and further optio