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Changes for page 3.4 Battery parameters

Last modified by Admin on 2026/04/24 10:30
From version 31.3
edited by Admin
on 2025/02/20 11:09
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To version 35.4
edited by Admin
on 2026/04/02 13:53
Change comment: Renamed back-links.

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1 -Battery management systems.BMS Main 2\.1.3\. Configuration.WebHome
1 +Battery management systems.EOL devices.BMS Main 2\.1.3\. 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,,)
84 +{{formula fontSize="SMALL"}}
85 +R = \frac{U_2-U_1}{I_{stable2}-I_{stable1}}
86 +{{/formula}}
83 83  
84 84  provided that
85 85  
86 -~{~{formula fontSize="SMALL"}}
87 -~| I_{stable2}-I_{stable1} | > 0.2 × Qmax
88 -~{~{/formula}}
90 +{{formula fontSize="SMALL"}}
91 +| I_{stable2}-I_{stable1} | > 0.2 × Q_{max}
92 +{{/formula}}
89 89  
90 -(Q,,max,, is the maximum cell capacity),
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.
91 91  
92 -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.
93 -
94 94  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.
95 95  
96 96  To change parameters of the algorithm for calculating the cell resistance, select the menu "Cells → Cell resistance estimation":
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134 134  * the voltage on the cell is less than the balancing stop voltage;
135 135  * the difference between the voltage on the cell and the minimum voltage among the battery cells is less than the balancing stop threshold.
136 136  
137 -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"]]).
139 +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.EOL devices.BMS Main 2\.1.3\. Configuration.3\.6 Battery protection.WebHome||anchor="HLogichightemperatureprotection"]]).
138 138  
139 139  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.
140 140  
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168 168  
169 169  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.
170 170  
171 -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.EOL devices.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.
172 172  
173 173  When charging the battery, balancing is performed based on the voltage of the series. A balancing resistor is connected to the cell series if:
174 174  
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255 255  
256 256  === Charge current map ===
257 257  
258 -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.
259 259  
260 260  Calculated currents values are sending to chargers over the CAN bus.
261 261  
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267 267  
268 268  * Enable – a flag to start calculation of the charge current limit;
269 269  * Maximum charging current – a maximum allowable value of the charge current (under normal conditions):
270 -* 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;
271 271  * Limit charging current by the contactor temperature – a flag to enable correction of maximum allowable charging current Kcc depending on the contactor temperature;
272 -* 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);
273 273  * Limit charging current by the maximum cell temperature – a flag to enable correction of maximum allowable charging current Kct depending on cell temperature.
274 274  
275 275  Value of the charge current limit at given SOC, temperature, contactors temperature and maximum cell voltage is calculated as follows:
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278 278  
279 279  === Discharge current map ===
280 280  
281 -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.
282 282  
283 283  Calculated currents values are sending or intellectual loads over the CAN bus.
284 284  
285 -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":
286 286  
287 287  [[image:1732208218667-968.png||data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="631" width="434"]]
288 288  
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291 291  * Enable – a flag to start calculation of the discharge current limit;
292 292  * Maximum discharging current – a maximum allowable value of the discharge current (under normal conditions):
293 293  * Current factor – the dependence of the correction factor on SOC and the battery temperature – Kdischarge=Kdischarge (SOC, t°C).
294 -* 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;
295 295  * Limit discharging current by the contactor temperature – a flag to enable correction of maximum allowable discharging current Kdc depending on the contactor temperature;
296 -* 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);
297 297  * Limit discharging current by the maximum cell temperature - a flag to enable correction of maximum allowable discharging current Kdt depending on cell temperature .
298 298  
299 299  Value of the discharge current limit at given SOC, temperature, contactors temperature and maximum cell voltage is calculated as follows: