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Changes for page 3.4 Battery parameters

Last modified by Admin on 2025/04/09 12:04
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61 61  
62 62  The SOC calculation algorithm “Current and voltage (enhanced)” differs from the simplified algorithm by online correction of effective capacitance. When using this algorithm, it is necessary to fine tune the tabular dependence Uocv = Uocv (SOC, t °C).
63 63  
64 -== 3.4.3 Cell resistance estimation ==
64 +3.4.3 SOC correction
65 65  
66 -Calculation of the resistance of cells is carried out in two ways. The first method is used when the battery passes from a relaxation state to a charge or discharge state, wherein the cell resistance value
67 -
68 -R = (U-Uocv) / Istable,
69 -
70 -where U is the cell voltage measured in the charge or discharge state, V; Uocv is the cell voltage measured in the state of relaxation (before switching to the state of charge or discharge); Istable – stabilized current through the cell in the state of charge or discharge.
71 -
72 -The second method is used for a stepwise change in the current through the cell, while the value of the cell resistance:
73 -
74 -R = (U,,2,,-U,,1,,) / (I,,stable2,,-I,,stable1,,) provided that | I,,stable2,,-I,,stable1,, | > 0.2 × Q,,max,,
75 -
76 -(Q,,max,, is the maximum cell capacity),
77 -
78 -where U,,2,, is the voltage on the cell at the moment when the stabilized current I,,stable2,, is flowing through it; U,,1,, – the voltage on the cell at the moment when the stabilized current I,,stable1,, flowing through it.
79 -
80 -The stabilized current I,,stable,, = I, if during the stabilization time the instantaneous current I is in the range from 0.95 × I to 1.05 × I.
81 -
82 -To change parameters of the algorithm for calculating the cell resistance, select the menu "Cells → Cell resistance estimation":
83 -
84 -== SOC correction ==
85 -
86 86  The BMS Main 2.x board can recalculate the battery SOC after long-term storage or after long-term working in the case when the battery was not charged fully or discharged totally. Recalculation is done based on the tabular dependency Uocv = Uocv (SOC, t) (see section Calculating the state of charge (SOC)).
87 87  
88 88  To configure parameters for periodically correcting the battery state of charge, select the menu "Cells → SOC correction":
89 89  
90 -[[SOC correction settings>>image:1732206262509-786.png||data-xwiki-image-style-alignment="center" height="291" width="298"]]
91 -
92 - In this section:
93 -
94 -* Enable – a flag to enable SOC correction;
95 -* Shutdown period – a time the battery is off, day. If the BMS detects on its startup that it was off during the “Shutdown period” time, the BMS recalculates the battery state of charge base on the tabular dependency Uocv = Uocv (SOC, t);
96 -* Correction period – a period of correcting the battery SOC, day. If the BMS detects that the last correction was more than the “Correction period” ago, the BMS recalculates the battery state of charge base on the tabular dependency Uocv = Uocv (SOC, t) and tunes it gradually during the “SOC change time”;
97 -* SOC change time – a duration of the linear changing the battery SOC to the value calculated by the correction algorithm, minute.
98 -
99 99