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Changes for page 3.4 Battery parameters

Last modified by Admin on 2025/04/09 12:04
From version 31.3
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on 2024/12/02 15:20
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1 -Battery management systems.BMS Main 2\.1.3\. Configuration.WebHome
1 +drafts.BMS Main 2\.1.3\. Configuration.WebHome
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1 -(% data-numbered-headings-start="3" style="--numbered-headings-start: 2;font-size: 0px;color: rgba(0, 0, 0, 0.0);margin-bottom: 0px; margin-top: 0px;" %)
2 -= Configuration =
1 +== 3.4.1 Cell defaults ==
3 3  
4 -(% data-numbered-headings-start="4" style="--numbered-headings-start: 3;font-size: 0px;color: rgba(0, 0, 0, 0.0);margin-bottom: 0px; margin-top: 0px;" %)
5 -== Battery parameters ==
6 -
7 -=== Cell defaults ===
8 -
9 9  To change the default cell settings, select the menu "Cells → Cell defaults":
10 10  
11 11  [[image:1732205873121-893.png||data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="281" width="374"]]
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26 26  
27 27  The “Reset cell parameters” command is used for starting-up and adjustment of battery.
28 28  
29 -=== SOC estimation ===
23 +== 3.4.2 SOC estimation ==
30 30  
31 31  The BMS Main 2.x board calculates the state of charge of the battery (SOC) using two algorithms:
32 32  
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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;
53 53  * Scale the final SOC – flag to scale the battery SOC by the following values;
54 54  * Internal SOC corresponding to 0% – battery SOC that sets to be 0%;
55 55  * Internal SOC corresponding to 100% – battery SOC that sets to be 100%.
56 -* Uocv = Uocv(SOC, t °C) – the dependence of the cell open circuit voltage Uocv on SOC and the cell temperature (selected for specific batteries, can be established experimentally – see [[Cell analysis>>doc:||anchor="HCellanalysis"]]);
48 +* Uocv = Uocv(SOC, t °C) – the dependence of the cell open circuit voltage Uocv on SOC and the cell temperature (selected for specific batteries, can be established experimentally – see [[3.4.6 Cell analysis>>doc:||anchor="H3.4.6 Cell analysis"]]);
57 57  * Linear zone – linear zone of dependence Uocv = Uocv(SOC, t °C):
58 58  ** Uocv ,,[point 1],, – starting point of the linear zone;
59 59  ** Uocv ,,[point 2],, – end point of the linear zone;
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69 69  
70 70  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).
71 71  
72 -=== Cell resistance estimation ===
64 +== 3.4.3 Cell resistance estimation ==
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  
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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,,)
74 +R = (U,,2,,-U,,1,,) / (I,,stable2,,-I,,stable1,,) provided that | I,,stable2,,-I,,stable1,, | > 0.2 × Q,,max,,
83 83  
84 -provided that
85 -
86 -~{~{formula fontSize="SMALL"}}
87 -~| I_{stable2}-I_{stable1} | > 0.2 × Qmax
88 -~{~{/formula}}
89 -
90 90  (Q,,max,, is the maximum cell capacity),
91 91  
92 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.
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105 105  * Minimum SOC – minimum cell SOC value for resistance calculation;
106 106  * Maximum SOC – maximum cell SOC value for resistance calculation.
107 107  
108 -The calculated resistance is accepted by the system as valid (and therefore updated) if its value is in the range from Resistance/2 to “Maximum resistance factor” × Resistance, where "Resistance" is the nominal resistance of the cell (see [[Cell defaults>>doc:||anchor="HCelldefaults"]]). If the calculated resistance value is greater than the value (Maximum resistance factor × Resistance), the updated resistance value will be equal to the value (Maximum resistance factor × Resistance).
94 +The calculated resistance is accepted by the system as valid (and therefore updated) if its value is in the range from Resistance/2 to “Maximum resistance factor” × Resistance, where "Resistance" is the nominal resistance of the cell (see [[3.4.1 Cell defaults>>doc:||anchor="3.4.1 Cell defaults"]]). If the calculated resistance value is greater than the value (Maximum resistance factor × Resistance), the updated resistance value will be equal to the value (Maximum resistance factor × Resistance).
109 109  
110 -=== Cell balancing ===
96 +== 3.4.4 Cell balancing ==
111 111  
112 112  The BMS Main 2.x supports two cell balancing algorithms:
113 113  
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129 129  * the voltage on the cell is higher than the starting voltage of the balancing;
130 130  * the difference between the cell voltage and the minimum voltage among the cells of the battery is greater than the balancing threshold.
131 131  
132 -A balancing resistor is disconnected from the cell if any of the following conditions are met:
118 +If the BMS Logic board overheats, then the balancing of the cells connected to this board will not be performed (see [[3.6.18 Logic high temperature protection>>doc:drafts.BMS Main 2\.1.3\. Configuration.3\.6 Battery protection.WebHome||anchor="H3.6.18 Logic high temperature protection"]]).
133 133  
134 -* the voltage on the cell is less than the balancing stop voltage;
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 -
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"]]).
138 -
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 -
141 -BMS Main 2.1 can force a cell balancing, if its voltage is higher than estimated value.
142 -
143 143  To change the cell balancing parameters, select the menu "Cell → Cell balancing":
144 144  
145 -[[image:1739812799920-892.png||alt="1732207485773-804.png" data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="264" width="387"]]
122 +[[image:1732207485773-804.png||data-xwiki-image-style-alignment="center" data-xwiki-image-style-border="true" height="264" width="387"]]
146 146  
147 147  In this section:
148 148  
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154 154  ** Charging;
155 155  ** Charging or relaxed;
156 156  ** Always (regardless of battery state);
157 -* Balancing condition:
158 -** Automatic – balancing will be performed automatically if needed conditions are met;
159 -** 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;
160 160  * Minimum cell voltage to start balancing, V;
161 -* Deviation to start balancing;
162 -* Deviation to stop balancing;
163 -* Voltage for forced balancing – if cell voltage is above this value, it will start discharging through balancing resistor;
135 +* Balancing threshold, V;
164 164  * Start cell discharging – a command to start forced balancing of all battery cells (used for service purposes);
165 165  * Stop cell discharging – a command to stop forced balancing of all battery cells (used for service purposes).
166 166  
167 -=== Series balancing ===
139 +== 3.4.5 Series balancing ==
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.
143 +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 [[3.3 Input and output signals>>doc:drafts.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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190 190  * Coulomb threshold – the difference of the charges Qthr, given by a series of cells, above which balancing to be started, Ah;
191 191  * Period – period to reset of charge counters for each series (to avoid accumulation of error), second.
192 192  
193 -=== Cell analysis ===
165 +== 3.4.6 Cell analysis ==
194 194  
195 -Discharge characteristics of the battery – the dependence Uocv = Uocv (DOD) – is used to determine the tabular dependence Uocv = Uocv (SOC, t °C) (see [[SOC estimation>>doc:||anchor="HSOCestimation"]]), which is necessary for calculating the state of charge of the battery.
167 +Discharge characteristics of the battery – the dependence Uocv = Uocv (DOD) – is used to determine the tabular dependence Uocv = Uocv (SOC, t °C) (see [[3.4.2 SOC estimation>>doc:||anchor="3.4.2 SOC estimation"]]), which is necessary for calculating the state of charge of the battery.
196 196  
197 197  The BMS Main 2.x board can automatically determine the battery discharge characteristic.
198 198  
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253 253  * OCV – cell voltage Uocv, V;
254 254  * Resistance – cell resistance, Ohm.
255 255  
256 -=== Charge current map ===
228 +== 3.4.7 Charge current map ==
257 257  
258 258  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.
259 259  
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276 276  
277 277  Charging current limit = Maximum charging current × Kcs × Kcc × Kcv × Kct.
278 278  
279 -=== Discharge current map ===
251 +== 3.4.8 Discharge current map ==
280 280  
281 281  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.
282 282  
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300 300  
301 301  Discharging current limit = Maximum discharging current × Kds × Kdc × Kdv × Kdt.
302 302  
303 -=== SOC correction ===
275 +== 3.4.9 SOC correction ==
304 304  
305 -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 [[SOC estimation>>doc:||anchor="HSOCestimation"]]).
277 +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 [[3.4.2 SOC estimation>>doc:||anchor="3.4.2 SOC estimation"]]).
306 306  
307 307  To configure parameters for periodically correcting the battery state of charge, select the menu "Cells → SOC correction":
308 308  
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