| The bypass switch is one of the key components of the lithium-ion battery pack for satellites.It is connected between the battery cells in the battery pack.Its function is to reliably remove the battery cells with performance faults from the battery pack.Thereby avoiding the performance failure of individual battery cells affecting the reliability of the entire battery pack.With the increasing number of new satellites using lithium-ion battery packs in China,the demand for bypass switches isincreasing.Due to the difficulty in purchasing and the high price,the localization requirements for bypass switches have been proposed.In order to meet the needs of China's key model satellite applications,this paper developed the design of a bypass switch with a rated current of 220 A.The research methods and some conclusions of this paper can be used to guide other bypass design of higher power or similar structures.Firstly,the design flow of the bypass switch contact system is established,and the mutual influence relationship between the elastic contact pressure,the pin's insertion and extraction force,the compression spring parameter and the pin stroke is clarified.Starting from the analysis of the components of the contact resistance of the bypass switch,the contact form between the lead and the pin is determined,and the three-dimensional model of the contact is constructed and the contact pressure is simulated.On this basis,the contact resistance of the bypass switch is calculated.The pin's insertion and extraction resistance is calculated according to the contact pressure,and then the calculation and analysis of the parameters of the compression spring are carried out;the switching process of the bypass switch is analyzed,and the stroke parameters of the pin are specified,and combined with the designed operation time of compressed spring for the switch and the first break time,the theoretical analysis and calculation are performed.Under the premise that the contact resistance,the operation margin and the time parameter all meet the requirements of the technical indicators,the design of the bypass switch contact system is completed.Then,the structural principle of the foreign bypass switch release device used SPLIT-SPOOL technique and the characteristics of the multi-lobed slider release stroke are analyzed.The structure of the release device of the bypass switch developed in this paper is designed.The force of the slider of the release device is analyzed to ensure that the function of releasing the push rod can be completed after the steel strip is released.The force of the steel strip is analyzed and calculated,and the tensile strength of the steel strip is measured.The data verified the theoretical calculation results;based on the measured fuse breaking force data,the analysis proves that the fuse can meet the long-term use requirements under this structure.Finally,the bypass switch was mass-produced according to the design structure and size parameters,and the insertion and extraction force,time parameter and contact resistance of the samples were measured(The operating time is 4.03ms?5.76 ms,the transition time of make-break is 246?s?332?s,the contact resistance is 0.067m??0.079m?,the operation margin of the switch's release process is more than 6 times);Combined with the requirements of the application verification of high-quality components of the aerospace system,the application test of the road switch is carried out,and the electrical stress,mechanical stress and temperature stress limit test capability of the bypass switch designed in this paper under the specified conditions are given.The test shows that the performance of the designed bypass switch is higher than the technical index.Claim.The obtained test data can be used as a reference for the aerospace engineering application of this type of bypass switch. |
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