Method for evaluating breakage of pole piece at cylindrical lithium battery positive tab
A technology for positive pole pieces and lithium batteries, which is applied in the direction of secondary batteries, circuits, electrical components, etc., and can solve the problems of not considering the influence of the shape of the winding core on the breaking force value, and not considering the different breaking strengths of the positive pole pieces.
Active Publication Date: 2021-04-06
LINKDATA NEW ENERGY CO LTD
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Problems solved by technology
[0004]
CN106405422A discloses a test method for the expansion and fracture of lithium-ion battery pole pieces, in which a tensile machine is used to test the fracture force value of pole pieces and wires, and the influence of the shape of the winding core on the fracture force value is not considered, nor is the positive pole piece taken into account. The problem of different breaking strengths in different parts of the film
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Embodiment 1
[0033] Example 1 The method for evaluating the fracture of the pole piece at the positive lug of a cylindrical lithium battery comprises the following steps:
[0034] S1: if figure 1 As shown, the positive pole piece breaking strength testing device is used to detect the positive pole piece breaking strength: according to the length of the positive pole piece a in the cylindrical lithium battery winding core from the center axis of the winding core, the end surface radius of the straight cylindrical pressing piece 1 is determined, and the positive pole piece The positive pole lug b section of piece a is pressed against the arc surface of the pressing piece 1 between the lower fixture 2 and the upper fixture 3 of the tensile machine, and the position of the positive pole lug b and the pressing piece 1 is the same as that of the positive pole lug b on the roll. The position in the core is consistent;
[0035] The bonding surface of the pressing piece 1 and the positive electrod...
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The invention discloses a method for evaluating breakage of a pole piece at a positive tab of a cylindrical lithium battery. The method comprises the following steps: measuring breaking strength of a positive pole piece; injecting a liquid into a cylindrical lithium battery roll core, packaging the cylindrical lithium battery roll core into an aluminum-plastic film to prepare an aluminum-plastic film battery, sleeving the aluminum-plastic film battery into a battery shell, carrying out charge-discharge cycle test on the aluminum-plastic film battery, and recording and obtaining a corresponding relationship between the charge-discharge cycle times and the expansion force measured by a film force sensor; and comparing the breaking strength of the positive pole piece in S1 with the measured value of the expansion force in S2 or the predicted value of the corresponding relationship, and evaluating the breaking risk of the pole piece at the positive tab of the cylindrical battery assembled by the cylindrical lithium battery roll core. According to the invention, the is reasonable in step, evaluates the breakage risk of the positive pole piece through experiments at the initial stage of battery development and design, such as material screening, is beneficial to shortening the development period and reducing the later failure risk of products.
Description
technical field [0001] The invention relates to the technical field of lithium-ion battery risk assessment, in particular to a method for assessing the fracture of a pole piece at a positive ear of a cylindrical lithium battery. Background technique [0002] With the continuous improvement of the energy density of lithium-ion batteries, the positive electrode material has developed from lithium cobalt oxide to NCM811 or NCA, and the negative electrode material has changed from graphite negative electrode to graphite composite silicon material, and the amount of silicon material added continues to increase. Silicon material expands greatly during charging and discharging, which causes the pole pieces and tabs in the cylindrical structure to bear greater stress, and if the battery design is unreasonable, it may cause the pole pieces, especially the tabs, to break and cause the lithium battery to fail, because The position adjacent to the positive tab is the position with the l...
Claims
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IPC IPC(8): G01N3/06G01N3/38H01M10/0525
CPCG01N3/06G01N3/38H01M10/0525G01N2203/0005G01N2203/0017G01N2203/0019G01N2203/005G01N2203/0676Y02E60/10
Inventor 杨威
Owner LINKDATA NEW ENERGY CO LTD