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Changes for page 3.4 Battery parameters

Last modified by Admin on 2026/04/24 10:30
From version 31.1
edited by Admin
on 2025/02/19 09:47
Change comment: There is no comment for this version
To version 35.9
edited by Admin
on 2026/04/24 10:29
Change comment: Update document after refactoring.

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1 -Battery management systems.BMS Main 2\.1.3\. Configuration.WebHome
1 +Battery management systems.BMS Main 2\.1 (End-of-Life).3\. Configuration.WebHome
Content
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73 73  
74 74  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
75 75  
76 -R = (U-Uocv) / Istable,
76 +{{formula fontSize="SMALL" imageType="PNG"}}
77 +R = \frac{U-U_{ocv}}{I_{stable}}
78 +{{/formula}}
77 77  
78 78  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.
79 79  
80 80  The second method is used for a stepwise change in the current through the cell, while the value of the cell resistance:
81 81  
82 -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}}
83 83  
84 -(Q,,max,, is the maximum cell capacity),
88 +provided that
85 85  
86 -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}}
87 87  
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 +
88 88  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.
89 89  
90 90  To change parameters of the algorithm for calculating the cell resistance, select the menu "Cells → Cell resistance estimation":
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162 162  
163 163  The BMS Main 2.x board supports work with two independent (galvanically unrelated) cell series. To monitor the status of two series, two current sensors are used: primary and secondary (AUX). A series of cells must be equivalent: they must have the same number of cells and the same capacity.
164 164  
165 -Since the series of cells can operate at different loads, they must be balanced. For this, the BMS Main 2.x provides two relays: “Balancing series 1” and “Balancing series 2” (see [[Input and output signals>>doc:Battery management systems.BMS Main 2\.1.3\. Configuration.3\.3 Input and output signals.WebHome]]), as well as a combined algorithm that considers both the voltage of each series and the charge that these series gave load. “Balancing series 1” and “Balancing series 2” relays are used to connect high-power balancing resistors in parallel with cells series 1 and 2.
173 +Since the series of cells can operate at different loads, they must be balanced. For this, the BMS Main 2.x provides two relays: “Balancing series 1” and “Balancing series 2” (see [[Input and output signals>>doc:Battery management systems.BMS Main 2\.1 (End-of-Life).3\. Configuration.3\.3 Input and output signals.WebHome]]), as well as a combined algorithm that considers both the voltage of each series and the charge that these series gave load. “Balancing series 1” and “Balancing series 2” relays are used to connect high-power balancing resistors in parallel with cells series 1 and 2.
166 166  
167 167  When charging the battery, balancing is performed based on the voltage of the series. A balancing resistor is connected to the cell series if:
168 168  
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249 249  
250 250  === Charge current map ===
251 251  
252 -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.
253 253  
254 254  Calculated currents values are sending to chargers over the CAN bus.
255 255  
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261 261  
262 262  * Enable – a flag to start calculation of the charge current limit;
263 263  * Maximum charging current – a maximum allowable value of the charge current (under normal conditions):
264 -* 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;
265 265  * Limit charging current by the contactor temperature – a flag to enable correction of maximum allowable charging current Kcc depending on the contactor temperature;
266 -* 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 U,,ocv,, voltage__ (corrected due to current and cell resistance);
267 267  * Limit charging current by the maximum cell temperature – a flag to enable correction of maximum allowable charging current Kct depending on cell temperature.
268 268  
269 269  Value of the charge current limit at given SOC, temperature, contactors temperature and maximum cell voltage is calculated as follows:
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272 272  
273 273  === Discharge current map ===
274 274  
275 -The BMS Main 2.x board calculates maximum allowable discharge current values in respect to SOC and battery temperature, contactor temperature and maximum cell voltage.
283 +The BMS Main 2.x board calculates maximum allowable discharge current values in respect to cell SOC and battery temperature, contactor temperature and minimum cell voltage.
276 276  
277 277  Calculated currents values are sending or intellectual loads over the CAN bus.
278 278  
279 -To configure parameters for determining the charge current limit, select the menu "Cells → Charge current map":
287 +To configure parameters for determining the discharge current limit, select the menu "Cells → Charge current map":
280 280  
281 281  [[image:1732208218667-968.png||data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="631" width="434"]]
282 282  
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285 285  * Enable – a flag to start calculation of the discharge current limit;
286 286  * Maximum discharging current – a maximum allowable value of the discharge current (under normal conditions):
287 287  * Current factor – the dependence of the correction factor on SOC and the battery temperature – Kdischarge=Kdischarge (SOC, t°C).
288 -* Limit discharging current by the battery SOC and temperature – a flag to enable correction of maximum allowable discharging current Kds depending on SOC and temperature;
296 +* Limit discharging current by the battery SOC and temperature – a flag to enable correction of maximum allowable discharging current Kds depending __on the minimum cell SOC__ and temperature;
289 289  * Limit discharging current by the contactor temperature – a flag to enable correction of maximum allowable discharging current Kdc depending on the contactor temperature;
290 -* Limit discharging current by the maximum cell voltage - a flag to enable correction of maximum allowable discharging current Kdv depending on maximum cell voltage;
298 +* Limit discharging current by the maximum cell voltage - a flag to enable correction of maximum allowable discharging current Kdv depending __the minimum cell U,,ocv,, voltage__ (corrected due to current and cell resistance);
291 291  * Limit discharging current by the maximum cell temperature - a flag to enable correction of maximum allowable discharging current Kdt depending on cell temperature .
292 292  
293 293  Value of the discharge current limit at given SOC, temperature, contactors temperature and maximum cell voltage is calculated as follows: