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Changes for page 3.4 Battery parameters

Last modified by Admin on 2026/04/24 10:30
From version 29.1
edited by Admin
on 2025/02/17 17:28
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To version 35.10
edited by Admin
on 2026/04/24 10:29
Change comment: Renamed back-links.

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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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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%.
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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":
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126 126  * the voltage on the cell is less than the balancing stop voltage;
127 127  * the difference between the voltage on the cell and the minimum voltage among the battery cells is less than the balancing stop threshold.
128 128  
129 -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.BMS Main 2\.1 (End-of-Life).3\. Configuration.3\.6 Battery protection.WebHome||anchor="HLogichightemperatureprotection"]]).
130 130  
131 131  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.
132 132  
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134 134  
135 135  To change the cell balancing parameters, select the menu "Cell → Cell balancing":
136 136  
137 -[[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"]]
138 138  
139 139  In this section:
140 140  
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146 146  ** Charging;
147 147  ** Charging or relaxed;
148 148  ** 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;
149 149  * Minimum cell voltage to start balancing, V;
150 -* 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;
151 151  * Start cell discharging – a command to start forced balancing of all battery cells (used for service purposes);
152 152  * Stop cell discharging – a command to stop forced balancing of all battery cells (used for service purposes).
153 153  
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155 155  
156 156  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.
157 157  
158 -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.
159 159  
160 160  When charging the battery, balancing is performed based on the voltage of the series. A balancing resistor is connected to the cell series if:
161 161  
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242 242  
243 243  === Charge current map ===
244 244  
245 -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.
246 246  
247 247  Calculated currents values are sending to chargers over the CAN bus.
248 248  
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254 254  
255 255  * Enable – a flag to start calculation of the charge current limit;
256 256  * Maximum charging current – a maximum allowable value of the charge current (under normal conditions):
257 -* 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;
258 258  * Limit charging current by the contactor temperature – a flag to enable correction of maximum allowable charging current Kcc depending on the contactor temperature;
259 -* 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);
260 260  * Limit charging current by the maximum cell temperature – a flag to enable correction of maximum allowable charging current Kct depending on cell temperature.
261 261  
262 262  Value of the charge current limit at given SOC, temperature, contactors temperature and maximum cell voltage is calculated as follows:
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265 265  
266 266  === Discharge current map ===
267 267  
268 -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.
269 269  
270 270  Calculated currents values are sending or intellectual loads over the CAN bus.
271 271  
272 -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":
273 273  
274 274  [[image:1732208218667-968.png||data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="631" width="434"]]
275 275  
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278 278  * Enable – a flag to start calculation of the discharge current limit;
279 279  * Maximum discharging current – a maximum allowable value of the discharge current (under normal conditions):
280 280  * Current factor – the dependence of the correction factor on SOC and the battery temperature – Kdischarge=Kdischarge (SOC, t°C).
281 -* 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;
282 282  * Limit discharging current by the contactor temperature – a flag to enable correction of maximum allowable discharging current Kdc depending on the contactor temperature;
283 -* 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);
284 284  * Limit discharging current by the maximum cell temperature - a flag to enable correction of maximum allowable discharging current Kdt depending on cell temperature .
285 285  
286 286  Value of the discharge current limit at given SOC, temperature, contactors temperature and maximum cell voltage is calculated as follows: