Internal resistance evaluation device and battery system

1 . A battery system comprising:

a plurality of battery packs, each of which includes a plurality of battery banks at a corresponding plurality of battery bank positions; and

a battery management system in communication with the plurality of battery packs and configured to:

measure, for the plurality of battery banks in each battery pack, a corresponding plurality of battery bank voltages and battery bank currents;

calculate a plurality of internal resistance (DCIR) values of the plurality of battery banks in each of the plurality of battery packs based on the corresponding plurality of battery bank voltages and battery bank currents;

classify the plurality of internal resistance values in each battery pack by the plurality of battery bank positions, and predetermine as a first position in each battery pack the position of a battery bank having a first internal resistance value determined to be outside of a normal range among the plurality of internal resistance values of the battery pack;

perform correction on the first internal resistance value at the predetermined first position in each battery pack; and

diagnose whether the battery bank at the predetermined first position is abnormal, based on the corrected first internal resistance value,

wherein the battery management system selects the corrected first internal resistance value as an actual internal resistance value of the battery bank at the predetermined first position in each battery pack,

wherein each of the plurality of battery banks includes a plurality of battery cells connected in parallel, and the predetermined first position is a same position in each of the plurality of battery packs, and

wherein in each battery pack, a mechanical resistance of the first internal resistance value of the battery bank at the predetermined first position is greater than that of the battery banks other positions in a corresponding battery pack.

2 . The battery system of claim 1 , wherein the battery management system corrects the first internal resistance value by multiplying the first internal resistance value by a predetermined ratio smaller than 1.

3 . The battery system of claim 2 , wherein the predetermined ratio is determined based on a result obtained by dividing the first internal resistance value of the battery bank at the predetermined first position in each battery pack by a median value of the plurality of internal resistance values of the plurality of battery banks constituting a corresponding battery pack.

4 . The battery system of claim 1 , wherein the battery management system comprises:

a plurality of monitoring ICs that are connected to the plurality of battery packs, and measures the plurality of battery bank voltages and battery bank currents of the plurality of battery banks; and

a main control IC that calculates the plurality of internal resistance values of the plurality of battery banks of each battery pack based on the plurality of battery bank voltages and battery bank currents, with respect to each of the plurality of battery packs, and corrects the first internal resistance value of the battery bank at the predetermined first position based on a correction ratio.

5 . The battery system of claim 4 , wherein the main control IC corrects the first internal resistance value of the battery bank at the predetermined first position by multiplying the first internal resistance value of the battery bank at the predetermined first position by the correction ratio, and

wherein the correction ratio is smaller than 1.

6 . The battery system of claim 5 , wherein the correction ratio is determined based on a result obtained by dividing the first internal resistance value of the battery bank at the predetermined first position in each battery pack by a median value of the plurality of internal resistance values of the plurality of battery banks constituting a corresponding battery pack.

7 . The battery system of claim 1 , wherein the battery management system comprises an internal resistance evaluation device comprising:

a normality verifying unit configured to verify normality with respect to the plurality of internal resistance values of the plurality of battery banks constituting each battery pack with respect to the plurality of battery packs;

a control chart analyzing unit configured to perform the classification of the plurality of internal resistance values in each battery pack by the plurality of battery bank positions and the predetermination of the first position in each battery pack; and

an internal resistance analyzing unit configured to perform the correction on the first internal resistance value at the predetermined first position in each battery pack.

8 . The battery system of claim 7 , wherein the internal resistance analyzing unit calculates a first value with respect to each of the plurality of battery packs by dividing the internal resistance value of the battery bank at the first position by a median value of the plurality of internal resistance values of the plurality of battery banks constituting each battery pack, and determines a degree of the correction based on an average of the plurality of first values with respect to all of the plurality of battery packs.

9 . The battery system of claim 8 , wherein the internal resistance analyzing unit determines, as the correction degree, a value obtained by subtracting 1 from the average of the plurality of first values.

10 . The battery system of claim 8 , wherein the normality verifying unit verifies the normality of the plurality of internal resistances at each battery bank position with respect to all of the plurality of battery packs.

11 . The battery system of claim 1 ,

wherein the battery management system estimates at least one of SOC (State of Charge), SOH (State of Health), and SOP (State of Power) based on the plurality of bank voltages of the plurality of battery banks and measured information on each of the plurality of battery packs.

12 . The battery system of claim 1 , wherein the battery management system controls and performs cell balancing on the plurality of battery banks of each of the plurality of battery packs based on the plurality of battery bank voltages.