A battery diagnosis system for a battery pack, wherein the battery pack comprises a battery group comprising a plurality of batteries connected in series; and a battery management system electrically coupled to two terminals of each of the plurality of batteries and configured to transmit a notification signal indicating a battery parameter of each battery, the battery diagnosis system comprising: a communication device configured to collect the notification signal via at least one of a wired network or a wireless network; a data preprocessing device configured to update big data indicating a change history of the battery parameter of each battery based on the notification signal; and a data analysis device configured to extract a data set including a plurality of characteristics values indicating the battery parameter of each of the plurality of batteries from the big data, determine dispersion information of the data set, and determine whether each battery is faulty based on the dispersion information and the plurality of characteristics values, wherein the dispersion information includes a standard deviation and an average of the plurality of characteristics values, wherein the data analysis device is configured to: at a predetermined time interval, for each battery, determine a deviation ratio, wherein the deviation ratio is a ratio of a deviation of interest to the standard deviation, and the deviation of interest is a difference between the average and the characteristics value, and determine a change in the deviation ratio, and wherein the data analysis device is configured to: at the predetermined time interval, determine a reference change based on an increase in accumulated energy used in charge/discharge from a manufacture time of the battery group, and determine each battery having the change in the deviation ratio that is larger than the reference change as faulty. a communication device configured to collect the notification signal via at least one of a wired network or a wireless network; a data preprocessing device configured to update big data indicating a change history of the battery parameter of each battery based on the notification signal; and a data analysis device configured to extract a data set including a plurality of characteristics values indicating the battery parameter of each of the plurality of batteries from the big data, determine dispersion information of the data set, and determine whether each battery is faulty based on the dispersion information and the plurality of characteristics values, wherein the dispersion information includes a standard deviation and an average of the plurality of characteristics values, wherein the data analysis device is configured to: at a predetermined time interval, for each battery, determine a deviation ratio, wherein the deviation ratio is a ratio of a deviation of interest to the standard deviation, and the deviation of interest is a difference between the average and the characteristics value, and determine a change in the deviation ratio, and wherein the data analysis device is configured to: at the predetermined time interval, determine a reference change based on an increase in accumulated energy used in charge/discharge from a manufacture time of the battery group, and determine each battery having the change in the deviation ratio that is larger than the reference change as faulty. at a predetermined time interval, for each battery, determine a deviation ratio, wherein the deviation ratio is a ratio of a deviation of interest to the standard deviation, and the deviation of interest is a difference between the average and the characteristics value, and determine a change in the deviation ratio, and wherein the data analysis device is configured to: at the predetermined time interval, determine a reference change based on an increase in accumulated energy used in charge/discharge from a manufacture time of the battery group, and determine each battery having the change in the deviation ratio that is larger than the reference change as faulty. at the predetermined time interval, determine a reference change based on an increase in accumulated energy used in charge/discharge from a manufacture time of the battery group, and determine each battery having the change in the deviation ratio that is larger than the reference change as faulty.