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Changes for page 3.4 Battery parameters

Last modified by Admin on 2025/04/09 12:04
From version 28.1
edited by Admin
on 2025/02/17 17:20
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To version 33.3
edited by Admin
on 2025/02/20 14:20
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... ... @@ -48,6 +48,8 @@
48 48  * Final SOC – a method of calculating the battery SOC:
49 49  ** Minimum cell SOC – the battery SOC is assumed to be equal to the minimum SOC of cells;
50 50  ** Average cell SOC – the battery SOC is assumed to be equal to the average SOC of cells;
51 +** Min-Max SOC – the battery SOC is calculated based on the minimum and maximum SOC of the cells. Final SOC will be a) 100% if any cell has 100% SOC, b) 0% if any cell has 0% SOC;
52 +** Max-Min SOC – the battery SOC is calculated based on the minimum and maximum SOC of the cells. Final SOC will be a) 100% if all cells have 100% SOC, b) 0% if all cells have 0% SOC;
51 51  * Scale the final SOC – flag to scale the battery SOC by the following values;
52 52  * Internal SOC corresponding to 0% – battery SOC that sets to be 0%;
53 53  * Internal SOC corresponding to 100% – battery SOC that sets to be 100%.
... ... @@ -71,18 +71,26 @@
71 71  
72 72  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
73 73  
74 -R = (U-Uocv) / Istable,
76 +{{formula fontSize="SMALL" imageType="PNG"}}
77 +R = \frac{U-U_{ocv}}{I_{stable}}
78 +{{/formula}}
75 75  
76 76  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.
77 77  
78 78  The second method is used for a stepwise change in the current through the cell, while the value of the cell resistance:
79 79  
80 -R = (U,,2,,-U,,1,,) / (I,,stable2,,-I,,stable1,,) provided that | I,,stable2,,-I,,stable1,, | > 0.2 × Q,,max,,
84 +{{formula fontSize="SMALL"}}
85 +R = \frac{U_2-U_1}{I_{stable2}-I_{stable1}}
86 +{{/formula}}
81 81  
82 -(Q,,max,, is the maximum cell capacity),
88 +provided that
83 83  
84 -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.
90 +{{formula fontSize="SMALL"}}
91 +| I_{stable2}-I_{stable1} | > 0.2 × Q_{max}
92 +{{/formula}}
85 85  
94 +where Q,,max,, is the maximum cell capacity; 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.
95 +
86 86  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.
87 87  
88 88  To change parameters of the algorithm for calculating the cell resistance, select the menu "Cells → Cell resistance estimation":
... ... @@ -121,11 +121,20 @@
121 121  * the voltage on the cell is higher than the starting voltage of the balancing;
122 122  * the difference between the cell voltage and the minimum voltage among the cells of the battery is greater than the balancing threshold.
123 123  
134 +A balancing resistor is disconnected from the cell if any of the following conditions are met:
135 +
136 +* the voltage on the cell is less than the balancing stop voltage;
137 +* the difference between the voltage on the cell and the minimum voltage among the battery cells is less than the balancing stop threshold.
138 +
124 124  If the BMS Logic board overheats, then the balancing of the cells connected to this board will not be performed (see [[Logic high temperature protection>>doc:Battery management systems.BMS Main 2\.1.3\. Configuration.3\.6 Battery protection.WebHome||anchor="HLogichightemperatureprotection"]]).
125 125  
141 +The BMS Main 2.1 can enable the cell balancing by the external “Balancing request” signal. Balancing process will be started to cells which the voltage is higher than the balancing start voltage and the difference between the cell voltage and the minimum voltage among all the cells is greater than the balancing stop threshold.
142 +
143 +BMS Main 2.1 can force a cell balancing, if its voltage is higher than estimated value.
144 +
126 126  To change the cell balancing parameters, select the menu "Cell → Cell balancing":
127 127  
128 -[[image:1732207485773-804.png||data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="264" width="387"]]
147 +[[image:1739812799920-892.png||alt="1732207485773-804.png" data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="264" width="387"]]
129 129  
130 130  In this section:
131 131  
... ... @@ -137,8 +137,13 @@
137 137  ** Charging;
138 138  ** Charging or relaxed;
139 139  ** Always (regardless of battery state);
159 +* Balancing condition:
160 +** Automatic – balancing will be performed automatically if needed conditions are met;
161 +** On balancing request – balancing will start only if a remote request is received. In this case cells will start to balance regardless the "Voltage deviation to start balancing" value;
140 140  * Minimum cell voltage to start balancing, V;
141 -* Balancing threshold, V;
163 +* Deviation to start balancing;
164 +* Deviation to stop balancing;
165 +* Voltage for forced balancing – if cell voltage is above this value, it will start discharging through balancing resistor;
142 142  * Start cell discharging – a command to start forced balancing of all battery cells (used for service purposes);
143 143  * Stop cell discharging – a command to stop forced balancing of all battery cells (used for service purposes).
144 144  
... ... @@ -233,7 +233,7 @@
233 233  
234 234  === Charge current map ===
235 235  
236 -The BMS Main 2.x board calculates maximum allowable charge current values in respect to SOC and battery temperature, contactor temperature and maximum cell voltage.
260 +The BMS Main 2.x board calculates maximum allowable charge current values in respect to cell SOC and battery temperature, contactor temperature and maximum cell voltage.
237 237  
238 238  Calculated currents values are sending to chargers over the CAN bus.
239 239  
... ... @@ -245,9 +245,9 @@
245 245  
246 246  * Enable – a flag to start calculation of the charge current limit;
247 247  * Maximum charging current – a maximum allowable value of the charge current (under normal conditions):
248 -* Limit charging current by the battery SOC and temperature – a flag to enable correction of maximum allowable charging current Kcs depending on SOC and temperature;
272 +* Limit charging current by the battery SOC and temperature – a flag to enable correction of maximum allowable charging current Kcs depending on the __maximum cell SOC__ and temperature;
249 249  * Limit charging current by the contactor temperature – a flag to enable correction of maximum allowable charging current Kcc depending on the contactor temperature;
250 -* Limit charging current by the maximum cell voltage – a flag to enable correction of maximum allowable charging current Kcv depending on maximum cell voltage;
274 +* Limit charging current by the maximum cell voltage – a flag to enable correction of maximum allowable charging current Kcv depending on __the maximum cell voltage__;
251 251  * Limit charging current by the maximum cell temperature – a flag to enable correction of maximum allowable charging current Kct depending on cell temperature.
252 252  
253 253  Value of the charge current limit at given SOC, temperature, contactors temperature and maximum cell voltage is calculated as follows: