TWI520409B - Battery cell balancing device and balancing method thereof - Google Patents

Description

Battery pack voltage balancing device and method

The present invention relates to a battery pack voltage balancing apparatus and method, and more particularly to a battery pack voltage balancing apparatus and method having a hybrid balancing architecture that can perform a consumable or non-consumable equalization operation.

In recent years, with the issue of climate change and energy conservation and carbon reduction, the issue of replacing petrochemical energy has promoted the hybridization of oil-electricity or pure electric vehicle industry. Among them, battery packs are indispensable key components. The battery cells with smaller volume and output voltage are connected in series and in parallel. In practical applications, since the nonlinear characteristics such as electrochemical characteristics and internal resistance of the battery cells are not completely the same, the difference in operating environment conditions also causes the respective battery cells to There are differences in electrical properties. When these series-parallel battery packs are used, some of the batteries may be overcharged while charging, but some batteries are undercharged, and the batteries are overcharged and over-discharged for a long time, which may cause unexpected problems to the battery modules. The loss of the battery accelerates the deterioration of the battery cell and reduces the service life of the battery module.

In order to increase battery durability, battery management systems generally design battery balancing functions, and the so-called balancing technology (also known as equalization technology) is mainly used to charge and discharge the series and parallel battery cells during use to make the cells The difference between capacity and voltage is as low as possible, which can be divided into non-consumable (also known as active) or consumable (also known as non-active) equalization technology, non-consumable equalization technology uses energy storage components such as capacitors and inductors to transfer energy between different cells, while consumption uses For example, the power resistor element instantaneously discharges different battery cells.

The present invention provides a battery pack voltage balancing device, comprising a battery pack having a plurality of battery cells, wherein the plurality of battery cells are electrically connected to each other; a switch array having a plurality of switches respectively associated with the battery pack The plurality of battery cells are electrically connected; the bus bar has a plurality of contacts respectively electrically connected to the plurality of battery cells in the battery group and the plurality of switches in the switch array; an energy regulation unit Electrically connecting the bus bar for adjusting the power required for equalizing the plurality of battery cells in the battery pack; a measuring unit electrically connecting the battery pack for measuring the battery pack The voltage, the charge and discharge current and the time, and the power consumed by the equalization; and a control and calculation unit electrically connecting the battery pack, the switch array, the energy regulation unit and the measurement unit, according to a certain The voltage charging set voltage value and the measurement result of the measuring unit calculate and control the switching sequence and the opening time of the plurality of switches in the switch array, and according to energy regulation Like element is a consumable or non-consumable operation like the operation to calculate a plurality of battery cells of these power adjustment time.

The present invention further provides a battery pack voltage balancing method, comprising: providing a battery pack voltage balancing device, the battery voltage balancing device comprising a battery pack having a plurality of electrically connected battery cells, and a switch array having a plurality of switches , a bus bar, an energy control unit, a measuring unit and a control And the computing unit, wherein the plurality of switches are electrically connected to the plurality of battery cells, the bus bar, and the control and computing unit, and the control and computing unit is electrically connected to the bus bar and the measuring unit And the energy regulating unit, the measuring unit is electrically connected to the battery pack and the control and computing unit, and is used for measuring voltage, current and operation time in the battery pack, wherein the energy regulating unit is used in the battery pack The plurality of battery cells are subjected to power adjustment required for equalization; and the set voltage value and the measurement result of the measuring unit are started according to a certain voltage in the battery pack, and the equalization program is started to calculate and control the switch array. The switching sequence and the opening time of the plurality of switches, and the battery cells are adjusted by the energy regulating unit such that the battery cells are subjected to equalization during the charging phase, and the plurality of battery cells or The individual positive and negative voltage differences of the plurality of strings of battery cells formed are less than a first allowable range when the constant current charge is converted to constant voltage charge.

In order to make the features and advantages of the present invention more comprehensible, the preferred embodiments are described below, and are described in detail with reference to the accompanying drawings.

210‧‧‧Battery Pack

211‧‧‧ battery core or string battery core

220‧‧‧Switch array

221‧‧‧ switch

230‧‧ ‧ busbar

231‧‧‧ positive lead

232‧‧‧Negative lead

240‧‧‧ energy control unit

250‧‧‧Control and calculation unit

260‧‧‧Measurement unit

510~590, 521~526‧‧‧ steps

1010~1040, 1031, 1032‧‧‧ steps

B ₁ ~B ₃ ‧‧‧Battery or string battery

△V‧‧‧ is used to calculate the voltage difference of different series of cells in the equalization time

△Q‧‧‧Different battery cells for calculating the equalization time

△T‧‧‧ used to calculate the difference in charging time of different string cells

Q _eq ‧‧‧ Equalization of electricity required

V _CV ‧‧‧ constant voltage charging setting voltage

The open circuit voltage measured by the OCV _i ‧‧‧ ith string cell after a period of charging to the end of the constant current charging phase

ΔV _i ‧‧‧The voltage difference between the ith string and the open circuit voltage at the end of the charging to constant current charging phase

△Vx _i ‧‧‧The voltage difference between the core of the i-string and the V _cv at the end of the charging to constant current charging phase

The expected open circuit voltage difference at the end of the OCVx _i ‧‧‧ ith string cell after equalization adjustment to the end of the constant current charging phase

Q _i ‧‧‧The actual discharge capacity obtained by OCV _i look-up table

Qx _i ‧‧‧The expected discharge capacity obtained by OCV _i look-up table

EQ _i ‧‧‧The amount of electricity to be equalized

1A and 1B are schematic diagrams showing an equalization operation according to an embodiment of the present invention.

2 is a block diagram of a battery pack voltage balancing device in accordance with an embodiment of the present invention.

3A is a schematic diagram of a hybrid equalization architecture in accordance with an embodiment of the present invention.

3B is a schematic diagram of a hybrid equalization architecture in accordance with another embodiment of the present invention.

4 is a schematic diagram of a consumption equalization operation in accordance with an embodiment of the present invention.

FIG. 5A is a flow chart of an embodiment of an equalization method corresponding to an embodiment of a consumption equalization architecture of the present invention.

FIG. 5B is a flow chart of an embodiment of an equalization weight correction method corresponding to an embodiment of a consumption equalization architecture of the present invention.

6 is a schematic illustration of the operation of an embodiment of a consumption equalization architecture in accordance with the present invention.

7A and 7B are schematic diagrams showing an example of an equalization weight correction operation corresponding to FIG. 5B.

FIG. 8 is a schematic diagram showing the effects before and after the non-consumption type equalization operation according to an embodiment of the present invention.

9A and 9B are schematic diagrams showing an operation example of an embodiment of a non-consumable equalization architecture according to the present invention.

10 is a flow chart of an embodiment of an equalization method corresponding to an embodiment of a non-consumable equalization architecture of the present invention.

FIG. 11 is a schematic diagram showing an example of measuring an equalization operation mode and an operation time according to an embodiment of the present invention.

1A and 1B are schematic views showing an equalization operation of the present invention. The present invention provides a new battery pack voltage balance or voltage equalization equalizer hardware architecture and equalization method, as shown in FIG. 1A, each battery cell has uneven capacity during charging due to different battery characteristics. The resulting loss of capacity is not the same, and the specific battery cell is more deteriorated. Therefore, the main purpose of the embodiment disclosed below is to convert the battery pack into constant voltage charging (CC) as shown in FIG. 1B. CV, Constant Voltage), the voltage of each string can reach the set voltage (CV) setting voltage at the same time, avoiding the specific battery at constant voltage (CV) Overcharge occurs continuously during charging, causing the battery to accelerate and deteriorate. In addition, by equalization control, in one embodiment, the battery cells with the highest battery string voltage are rotated, and the overcharged damage is evenly distributed on all the battery cells of the battery pack. The curve in Figure 1B is the voltage change of a string of cells relative to time.

2 is a block diagram of a battery pack voltage balancing device in accordance with an embodiment of the present invention. In this embodiment, a battery pack 210 having a plurality of electrically connected battery cells 211, a switch array 220 having a plurality of switch units 221, a bus bar 230, an energy regulation unit 240, and a control computing unit are included. 250 and a measuring unit 260, wherein the switches 221 are electrically connected to the plurality of battery cells 211, the bus bar 230, and the control and computing unit 250, respectively, and the control and computing unit 250 is electrically connected to the bus bar 230 and the energy regulating unit 240. .

In an embodiment, the energy regulating unit 240 is configured to adjust the power required for equalizing the plurality of battery cells in the battery pack; and start the first-class charging voltage V _CV according to a certain voltage in the battery pack. The plurality of switching units 221 in the control program control switch array 220 switch and control the energy regulating unit 240 such that the battery cells 210 are formed or composed of a plurality of battery cells 211 during a plurality of charging cycles of the equalization operation in the charging phase. The individual positive and negative voltage differences of the plurality of string cell groups 211 are less than a allowable range V _T when the constant current charging is converted to constant voltage charging, and the control and calculation unit 250 controls the energy regulation according to the electrical measurement of the battery pack. Unit 240 performs a consumption equalization operation or a non-consumption equalization operation.

In another embodiment, the bus bar may be composed of a positive electrode lead 231 and a negative electrode lead 232, and the switch array is respectively connected to the positive and negative lead wires 231, 232 of the bus bar respectively. , where the switch Unit 221 contains two switching elements.

3A is a schematic diagram of a hybrid equalization architecture in accordance with an embodiment of the present invention. This hybrid equalization architecture corresponds to the hardware architecture of the aforementioned FIG. 2 embodiment. In one embodiment, the battery array that needs to be equalized is mounted to the bus bar for power regulation by using the switch array, and the hybrid architecture of the consumable or non-consumable equalization can be switched according to requirements. When the equalizing device connected to the bus bar in the energy regulating unit 240 is a simple energy consuming element, it is equivalent to the consumption type equalization, and only the battery can be discharged, but the battery cannot be charged. The energy consuming component mounted on the busbar can be a power resistor or an associated energy consuming component in the battery pack, such as a cooling fan or a battery pack preheater. Corresponding to the energy regulation unit 240 mounted on the bus bar is a DC bidirectional converter with an energy storage component (battery or capacitor) or an inductance component, and the string cell discharge is equivalent to charging the energy storage component battery. Conversely, when the energy storage element is discharged, it is equivalent to charging the string battery. This architecture is non-consumable equalization. In the case of non-consumable equalization, the DC bidirectional converter and the energy storage element can also be mounted outside the battery, and the battery can be equalized by the factory inspection using the battery pack voltage balancing device.

3B is a schematic diagram of a hybrid equalization architecture in accordance with another embodiment of the present invention. This hybrid equalization architecture also corresponds to the hardware architecture of the aforementioned FIG. 2 embodiment. In an embodiment, if only the resistor is installed on the bus bar end, the foregoing switch array 220 can be simplified to the above-illustrated structure as shown in the figure, wherein the foregoing switch unit 221 can include only one switching element. In another embodiment, the equalization switch array can also be switched to the bus bar first, and then according to the positive and negative polarity of the bus bar, the polarity is adjusted to the correct value after the switch is switched, as shown in the figure below in the figure. , wherein the equalization device connected to the bus bar in the foregoing energy regulation unit 240 can simultaneously Mount consumable and non-consumable components and switch with another set of switch units.

In many practical applications of traditional consumable equalization architectures, a battery-based management system (BMS) circuit board is provided with a consumable balancer circuit, and the energy-consuming components are disposed on the battery management system circuit board, but this The design will cause the waste heat generated by the power resistor to be conducted to other components on the BMS board when the equalization is turned on, which will cause the parts on the BMS board to accelerate and deteriorate, and even affect the operation and stability of each function of the board. It is also limited by the volume and heat dissipation design of the BMS board, and is not suitable for configuring high-power resistors. Such a design causes disadvantages such as equalization of energy dispersion and small equalization current of each string cell. However, in another embodiment, the energy regulation unit is disposed outside the BMS circuit board and the switch array board, and is externally mounted on the bus bar, so the battery management system circuit board When only the conduction switch is generated, the current flows through the heat generated by the switch impedance, which can perform high-power equalization operation, shorten the time required for battery pack balancing, and improve the flexibility and performance of the battery management system in design and use.

4 is a schematic diagram of a consumption-type equalization operation according to an embodiment of the present invention. The upper battery cell voltage curve shown in the figure will have the voltage curve shown below after the equalization operation. In one embodiment, the battery pack is converted to constant voltage charging (CV, Constant Current). In Constant Voltage, the voltage of each string of cells can reach the constant voltage charging setting voltage at approximately the same time. In addition, in order to prevent the specific battery from continuously overcharging during constant voltage charging, the battery core is accelerated to deteriorate. The cells with the highest battery string voltage can be rotated by equalization control, and the overcharged damage is evenly distributed on all the battery cells of the battery pack.

5A is a diagram of an embodiment of a consumable equalization architecture in accordance with the present invention. Equalization method flow chart. This equalization method can be applied to the hardware architecture corresponding to the embodiment of FIG. 2 to FIG. 3B. In an embodiment, after the equalization operation is started, in the constant current charging phase, step 510 determines that when any battery in the battery pack reaches the constant voltage charging setting value set by each string cell, first proceeds to step 520 for weighting. Coefficient correction, wherein the correction method will be described in detail in the following description of the embodiment of FIG. 5B, which is skipped here. If it is the initial equalization operation, the weight coefficient is a preset value, and then proceeds to step 530 to calculate the battery pack. The pressure difference between the highest and lowest string cells is determined in step 540 to determine that the equalization control is initiated when the pressure difference exceeds the allowable range. After step 550 to step 590, the string voltage of the highest voltage of the battery pack is adjusted by the capacity, and the next time the constant current is charged until the string voltage reaches the constant voltage charging set value, the last highest voltage string battery is in this time. The voltage at the end of the constant current is less than or equal to the string voltage of the previous lowest voltage. In another embodiment, after all the string cells can be adjusted in capacity at one time, the equalization operation methods of the two embodiments can make the voltages of all the strings can be reached substantially simultaneously when the current is charged. The set value of voltage charging.

It is further explained that there are two equalization operation modes in the consumption equalization control method disclosed in the above embodiments, wherein steps 570 to 580 are mode A, and steps 550 to 560 are mode B, when the battery cell group is The highest string voltage value in the difference between the highest string voltage value and the lowest string voltage value exceeds a differential pressure set value, and the control and calculation unit calculates the equalization operation time in step 550 to maintain the corresponding current time in the switch array in the time interval. The switch of the program is performed, and the string battery core having the highest string voltage value is discharged to be lower than the lowest string voltage value, and step 560 determines whether the switch has been turned on beyond the equalization operation time, and if it is exceeded, the switch corresponding to the equalization operation is turned off. Conversely, if the highest string voltage value in the string cell group If the difference from the lowest string voltage value is less than a differential pressure set value, the mode A is equalized, and in step 570, the string cell is discharged to a specific proportional power, for example, 1% SOC (State of Charge), and step 580 is determined. Whether the equalization operation switch time reaches a certain proportion of the electric discharge time set value, and if the set value has been reached, the switch corresponding to the equalization operation is turned off, and the mode A equalization operation operates the plurality of serial battery cells in the battery pack in different charging cycles. A rotation operation that performs a specific proportional amount of electricity.

In an embodiment, the aforementioned allowable differential pressure range V _T may be more than twice the voltage measurement error. In addition, the aforementioned battery cell capacity adjustment refers to discharging a specific string cell, and the discharge capacity is calculated as: Qeq _i = ΔV*w _i , where Qeq _i is the i-th string cell equalization The discharge quantity, ΔV is the voltage difference of the highest string voltage of the battery pack minus the lowest string voltage of the battery pack, and w _i is the weight coefficient of the ith string battery, which is equivalent to the capacity difference (mAh) corresponding to the differential pressure per mV. And the previously mentioned w _i weight coefficient, its correction formula: w _i (n) = Q _eq (n-1) / (ΔV (n-1) - ΔVx (n)), where w _i (n) Indicates the weight coefficient of the i-th string of cells at the nth equalization, and the capacitance of the Q _eq (n-1) table before equalization. ΔV(n-1)=V _max (n-1)-V _min( n-1), where ΔV(n-1) is the high and low voltage difference of the battery string at the end of the previous constant current charging, V _max (n-1) and V _min (n-1) are the highest and lowest voltages at the end of the constant current charging phase of the previous charging, ΔV _x (n)=V _H (n)-V _L (n), where When this table is charged until any battery reaches the constant voltage charging setting voltage, the voltage difference between the highest battery string and the lowest battery string cell before the previous equalization, V _H (n) is the string of the previous highest voltage. The voltage at which the core is at the end of this constant current charge. V _L (n) is the voltage of the last lowest voltage string cell at the end of this constant current charging.

FIG. 5B is a flow chart of an embodiment of an equalization weight correction method according to an embodiment of a consumption equalization architecture according to the present invention. This embodiment corresponds to the foregoing step 520 in the equalization method of FIG. 5A and is equally applicable to the hardware architecture corresponding to the embodiment of FIG. 2 to FIG. 3B. Step 521 determines whether the actual equalization time tr_eq is greater than a set value, and if so, proceeds to step 522 based on the previous equalization weight coefficient w _i (n-1): the previous equalization time weight coefficient is used to calculate the actual equalization time. The corresponding differential pressure dV _{C is} calculated as: dV _C = (tr_eq) / w _i (n-1). Next, proceeding to step 523, the pressure difference dV _r actually generated by the equalization is calculated, and the calculation formula is: dV _r = V _{max_last} (n) - V _{min_last} (n), wherein V _{max_last} (n) is the previous highest voltage in this time. The voltage of the feature point, V _min (n) is the voltage of the previous lowest voltage at the current feature point, and the feature point is defined as any one of the string cells reaching the set CV voltage. Then, step 524 is performed to calculate an equalization differential pressure error value E, which is calculated as: E=dV _C -dV _r , and then step 525 determines whether the error value E is greater than a set value, and if yes, proceeds to step 526 to modify the weight coefficient w _i , and corrects The method is: w _i (n)=tr_eq/(dV _r ), otherwise the equalization weight coefficient correction operation is ended.

FIG. 6 is a schematic diagram showing an operation example of an embodiment of a consumption equalization architecture according to the present invention. In an embodiment, the string cell with the highest battery string voltage can be rotated by equalization control, and any battery cell in the battery pack reaches the constant voltage charging set by each string cell in the constant current charging phase. When setting the value, calculate the pressure difference between the highest and lowest series of battery cells in the battery pack. When the pressure difference exceeds the set range, the equalization control is started. The purpose is to adjust the current voltage of the highest voltage string to the next time. When the current is charged until the string voltage reaches the constant voltage charging set value, the voltage of the last highest voltage string battery at the end of the current charging is less than or equal to the previous lowest voltage string, that is, on the one hand The highest voltage string battery position is rotated, and the other side is reduced by the rotation adjustment process. High and lowest pressure difference. After the equalization adjustment in the two charging stages as shown in the figure, the voltages of the string cells B1 to B3 are nearly uniform.

7A and 7B are schematic diagrams showing an example of the equalization weight coefficient correction operation corresponding to FIG. 5B. In an embodiment, it is determined whether the highest and lowest differential pressures of all the string cells exceed a set value, and if the set value is exceeded, the equalization capacity calculation function is started. It is assumed that the voltage of Cell03 is the highest, the voltage of Cell01 is the lowest, the high and low voltage difference ΔV is 30 mV, and the weight coefficient w3 of the third string cell Cell03 is also the capacity magnification relationship per mV of 13, which corresponds to the capacity Qeq of 390 mAh.

The equalization time is calculated as t = 3600 * (Qeq / Ieq), assuming that the equalization current Ieq is about 1000 mA. Therefore, the equalization time is t=3600*(Qeq/Ieq), t=3600*390/1000=1404 seconds. It can be seen that the greater the high and low pressure difference, the longer the required equalization time.

After the equalization adjustment, the constant voltage charging set voltage V _CV is entered again during the next charging. At this time, the highest voltage is Cell02, but the cell03 does not fall to the same pressure difference as Cell01, and the following two conditions may occur:

Condition 1: C _Cell03 >V _{Cell01 is} about 10mV, which means that according to the parameter of w3=13, 390mAh is only adjusted by about 20mV (△V1=30-10), so the w3 parameter should be corrected to w3=Qeq/△V1= when used next time. 19. In other words, the previous equalization capacity should actually cost 570mAh (19*30) to pull the voltage down 30mV. The next time if the voltage switched to Cell03 is the highest, then Qeq is calculated as w3=19.

Condition 2: V _Cell03 <V _{Cell01 is} about 20mV, which means that according to the parameter of w3=13, 390mAh lowers the battery by 50mV (△V1=30-(-20)), so the w3 parameter should be corrected to w3=Qeq/(△ V-ΔV1)=390/50=7.8. In other words, the previous equalization capacity should actually take 234mAh (30*7.8) to pull the voltage down by 30mV. The next time if the voltage switched to Cell03 is the highest, then Qeq is calculated as w3=7.8.

In short, when the equalization fails to achieve the expected goal, an embodiment of the present invention has a weight coefficient w self-correction mechanism. If the equalization time is too long, the adjusted pressure difference is lower than expected, then the differential pressure before and after the adjustment will be w is small; on the other hand, if the equalization time is too short, the pressure difference after adjustment is higher than expected, then w is adjusted according to the pressure difference before and after adjustment.

According to the above manner, by repeatedly correcting the w parameter of each battery, the battery can be recharged and then charged into the constant voltage charging set voltage V _CV , and the previous highest voltage string cell can be slightly lower than the previous one. The lowest voltage string cell.

Fig. 8 is a schematic view showing the effects before and after the non-consumption type equalization operation of the present invention. For some conventional equalization techniques, if the battery element is over-discharged due to parameter estimation errors during the equalization, the differential pressure amplification when the constant current charging phase CC enters the constant voltage charging phase CV will occur. It takes a long time to remedy it. At this time, it is necessary to adjust the non-consumable equalization method to restore the voltage balance of the battery pack in a short time. In an embodiment of the present invention, the purpose of balancing the battery pack by external non-consumption equalization is to pull the excessive pressure difference first (coarse adjustment), and then with the internal consumption equalization. Fine-tune the differential pressure.

In one embodiment, after all the battery cells can be adjusted in capacity at one time, the next time the constant current charging is performed, the voltages of all the series of battery cells can reach the set value of the constant voltage charging at the same time, and the calculation method of the capacitance adjustment includes When the battery pack is charged at a constant current until any string voltage reaches the constant voltage charging set voltage V _CV , the open circuit voltage of each string of cells is obtained after standing for a set period of time, and each string of cells is calculated to be stationary. The voltage difference between the front and the back is calculated as ΔV _i =(V _i -OCV _i ), where ΔV _i indicates that the ith string battery is charged to the voltage difference between the end of the constant current charging and the open circuit voltage, and the OCV _i meter is charged to the constant current. The open circuit voltage measured for a period of time after the end of charging. The amount of electricity that each cell needs to be equalized is calculated according to the open circuit voltage of each string of cells, and the calculation method is EQ _i = Qx _{i -} Q _i . EQ _i is the capacity of the i-th string battery core to be equalized. Here, the non-consumable equalization operation may be charging or discharging, and Qx _i is the expected residual electric quantity value of each string of battery cells entering the constant voltage charging phase, Q _i is the actual residual power at the end of the constant current charging, and i represents the ith string battery core. Q _i is calculated by taking OCV _i using the open circuit voltage of each string of cells corresponding to the discharge charge meter to obtain Q _i by the internal difference method. Qx _i is used to charge each string of battery cells to a desired capacitance value corresponding to a constant voltage point, and the calculation of the desired capacitance value is obtained by looking up the expected open circuit voltage OCVx _i corresponding to the discharge electricity meter table, and calculating the desired open circuit voltage value. The mode is OCVx _i = V _cv - ΔV _i .

9A and 9B are schematic diagrams showing an operation example of an embodiment of a non-consumable equalization architecture according to the present invention. This example disclosed and other non-consumable string operation object determined to charge the battery cell B3 to how much power at the end of the constant current charging, V the voltage may be a voltage of approximately ₃ V _CV's. And so on, how much power is required for the battery cells B2 and B1, so that the battery cores B1~B3 can simultaneously reach the voltage of V _CV at the next charging.

In this example illustration, ΔV ₃ =V ₃ -OCV ₃ , that is, the voltage difference due to internal resistance at the end of constant current charging; and ΔVx ₃ =Vcv-V ₃ , that is, battery cell B3 is constant current charging voltage V _CV differential pressure at the end; as _{OCVx 3 = OCV 3 + △ Vx} 3, showing equalized after adjustment, the desired constant current charge at the end of the open circuit voltage; Qx ₃ is a look-up table to OCVx ₃ ( OCV-Ah table) The expected discharge power obtained; OCV ₃ is the true open circuit voltage at the end of constant current charging before equalization adjustment; Q ₃ : true discharge power obtained by OCV ₃ look-up table (OCV-Ah table) And EQ ₃ = Qx _{3 -} Q ₃ , and the capacity of the battery core B3 to be equalized is the difference between the expected discharge power after equalization and the actual discharge power before the equalization.

By this equalization operation, it is expected that after the next equalization, the voltage of V ₃ (n+1) will be very close to the voltage of V _CV at the end of the constant current charging, and will be allowed to stand after the end of the constant current charging. open circuit voltage will be approximately ₃ OCVx desired value, etc. Similarly calculate the charge of the battery cells B1, EQ _1.

10 is a flow chart of an embodiment of an equalization method in accordance with an embodiment of a non-consumable equalization architecture in accordance with the present invention. This equalization method is equally applicable to the hardware architecture corresponding to the embodiment of FIGS. 2 to 3B. In this embodiment, after the start of the equalization process, the process proceeds to step 1010 to determine whether the battery cell power measurement function is normal. If not, the equalization operation is left. In addition, in this step, when charging starts after the battery is discharged, the equalizing power calculation function is started, when the voltage of any of the battery cells in the battery pack reaches the set constant voltage charging setting voltage V _CV , for example, 4100 mV, at this time, The voltage difference EQ_EN_ΔV of the string of cells in the battery pack is further measured, for example, 20 mV, and if the pressure difference is greater than a set value, the process proceeds to step 1020. If not, leave the equalization operation. In step 1020, the charger is turned off and waits for a set time, for example 300 seconds, to return all battery voltages to approximately OCV _i , then calculate ΔVi = (V _i -OCV _i ), and then proceeds to step 1030 to calculate each The equalized amount of electricity EQ _i required for the string of cells, that is, EQ _i =Qx _i -Q _i . Where Ox _i is the desired residual power value of each string of cells entering the constant voltage charging phase, Q _i is the actual residual power at the end of the constant current charging, and i represents the ith string of cells. This calculation are the following two sub-steps 1031 and 1032, sub-step 1031 calculates Qx _i, is calculated to obtain the first _{OCVx i = V cv - △ V} i, and then using the OCV-Ah OCVx _x look-up table to obtain the corresponding Qx _i . Sub-step 1032 performs the calculation of Q _i in such a manner that OCV _i obtains Q _i using the OCV-Ah correspondence table. Finally, step 1040 is performed. According to the EQ _{x of} each battery, an equalization switch corresponding to the battery core is turned on to perform equalization charging or discharging of the string of battery cells. And during the equalization process, the battery can be allowed to operate normally.

The above embodiments illustrate a detailed description of the battery pack voltage balancing device of the consumable and non-consumable hybrid architectures and the equalization operation method corresponding to different requirements. The control calculation and measurement unit operation mechanism in the hardware architecture corresponding to the embodiment of FIG. 2 to FIG. 3B can be further described by determining the equalization operation time and the like by the measurement result of FIG. 11 . In an embodiment, the voltage difference ΔV _i or the power difference ΔQ _i or the charging time difference ΔT _{i of the} different series of battery cells can be matched with the corresponding weight coefficients W _V (i), W _Q (i Or W _T (i) calculates the charge and discharge time T _eq (i) required for the equalization operation of different strings of cells. Alternatively, the charge and discharge electric quantity Q _eq (i) required for the equalization operation is calculated by the measurement result, and the equalization current can further determine the charge and discharge time T _eq (i) required for the specific string battery core.

For example, as shown in FIG. 11 corresponding to the voltage variation curve of the 12-string battery core, the string voltage of the string battery core AuxV8 first reaches a certain voltage charging setting voltage of 4.06V and the electric quantity is 44.7Ah at the charging time of 830 seconds, another string The battery core AuxV3 has a power of 47.7 Ah at a string voltage of 4.06 V and a charging time of 1430 seconds. For the string battery AuxV1, when the string voltage reaches 4.06V, the power is 46.5Ah, and the charging time is 1200 seconds. In addition, from the point of reaching the same amount of electricity 47Ah, the string voltage of the string cell AuxV8 is 4.087V, the string voltage of the string cell AuxV3 is 4.053V, and the string voltage of the string cell AuxV1 is 4.066V.

If the non-consumable equalization operation of the string cell AuxV1 is selected, the voltage curve is close to the voltage curve of the string cell AuxV8, and the string voltage difference ΔV _AuxV1 and the power difference _ΔQ according to the string cell AuxV1 and the string cell AuxV8 can be _selected . _AuxV1 or charging time difference ΔT _AuxV1 calculates the charging time T _eq (AuxV1) for equalizing the string cell _AuxV1 with the corresponding weight coefficients W _V (AuxV1), W _Q (AuxV1) or W _T (AuxV1), respectively. It is ΔT _AuxV1 *W _T (AuxV1), ΔV _AuxV1 *W _V (AuxV1) or _{ΔQ AuxV1} *W _Q (AuxV1).

Similarly, if the battery cell AuxV1 is subjected to a consumption equalization operation such that the voltage curve is close to the string voltage of the string cell AuxV3, the string voltage difference, the power difference or the charging time difference according to the string cell AuxV1 and the string cell AuxV3 can be selected. The discharge time for equalizing the string cell AuxV1 is calculated separately from the corresponding weight coefficient.

Compared with some conventional single-consumption or single non-consumption-based equalization techniques, the hybrid equalization architecture disclosed in the above embodiments can be mounted on the busbar by mounting consumable or non-consumable equalization components. The waste heat generated by the equalization operation is transferred to the outside of the battery management circuit board and the equalization current of the single string battery core is increased. If a non-consumable equalization circuit is installed, and the battery cell voltage is nearly saturated or drained, the corresponding equalization operation mode of the elastic selection is charging or discharging, and avoiding the single direction balancing may have an inoperable interval or low performance. .

Unless otherwise defined, all terms (including technical and scientific terms) are used in the ordinary meaning In addition, unless explicitly stated, the definition of vocabulary in a general dictionary should be interpreted as The articles in the related art have the same meaning and should not be interpreted as an ideal state or an excessively formal voice.

Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

210‧‧‧Battery Pack

211‧‧‧ battery core or string battery core

220‧‧‧Switch array

221‧‧‧ switch

230‧‧ ‧ busbar

231‧‧‧ positive lead

232‧‧‧Negative lead

240‧‧‧ energy control unit

250‧‧‧Control calculation

260‧‧‧Measurement unit

Claims (20)

A battery pack voltage balancing device includes: a battery pack having a plurality of battery cells, wherein the plurality of battery cells are electrically connected to each other; and a switch array having a plurality of switches and the plurality of switches in the battery pack The battery cells are electrically connected; a bus bar having a plurality of contacts respectively electrically connected to the plurality of battery cells in the battery pack and the plurality of switches in the switch array; an energy control unit, The battery is connected to the busbar for adjusting the power required for equalizing the plurality of battery cells in the battery pack; a measuring unit electrically connected to the battery pack for measuring the battery pack Voltage, current and operation time; and a control and calculation unit electrically connected to the battery pack, the switch array, the energy regulation unit and the measuring unit, and the set voltage value according to a certain voltage and the measurement of the measuring unit As a result, the switching sequence and the opening time of the plurality of switches in the switch array are calculated and controlled, and the energy regulating unit is a consumption equalization operation or a non-consumption equalization operation. Calculated for each time series cell energy adjustment. The battery voltage balancing device of claim 1, wherein the energy adjusting unit comprises an energy consuming component or an energy storage component, wherein the energy consuming component is a consumable equalization structure, and the equalizing current direction is only a discharge. If it is composed of energy storage components, it is a non-consumable equalization architecture, and the equalization current direction can be charged and discharged in both directions. The battery pack voltage balancing device according to claim 1, wherein The plurality of battery cells in the battery pack are electrically connected in series. The battery voltage balancing device of claim 1, wherein the bus bar has two wires, one of which is a positive wire for equating the plurality of string cells, and the other is a negative wire. The battery voltage balancing device of claim 4, wherein the plurality of switches in the switch array respectively comprise the plurality of battery cells in the battery pack or a plurality of battery cells composed of the battery cells The positive and negative poles of the group are connected to the positive and negative conductors of the busbar. The battery voltage balancing device of claim 1, wherein the control and calculation unit calculates the battery of the next use cycle according to the voltage, the charging and discharging current and the time of the plurality of battery cells in a charging cycle. The amount of electricity or time required for the core to be equalized. The battery voltage balancing device of claim 1, wherein the control and calculation unit calculates the time required for the equalization according to the current direction and size of the energy regulation unit. The battery voltage balancing device of claim 2, wherein the energy consuming component comprises one of a power resistor, a fan, a heater, or any combination thereof, and the energy regulating unit is disposed to include the One of the battery pack voltage balancing devices is external to the battery management system board. The battery voltage balancing device of claim 2, wherein the energy storage component comprises one of a capacitor, an inductor, a battery, a DC bidirectional converter, or any combination thereof, and the energy regulation unit It is disposed outside the battery management system circuit board that includes one of the battery pack voltage balancing devices. The battery pack voltage balancing device according to claim 1, wherein The battery pack voltage balancing device is adapted to allow the battery pack to be subjected to equalization during the charging phase, the plurality of battery cells or individual positive and negative poles of the plurality of string battery core groups The voltage difference is less than a first allowable range when the constant current charging phase is converted to the constant voltage charging phase, and the individual positive and negative voltage differences of the plurality of string cell groups are consistently entered into the constant voltage charging phase during a certain charging cycle. A battery pack voltage balancing method includes: providing a battery voltage balancing device, the battery voltage balancing device comprising a battery pack having a plurality of electrically connected battery cells, a switch array having a plurality of switches, and a bus bar An energy control unit, a measurement unit, and a control and calculation unit, wherein the plurality of switches are electrically connected to the plurality of battery cells, the bus bar, and the control and calculation unit, respectively, and the control and calculation The unit is electrically connected to the bus bar and the energy regulation unit, and the measurement unit is electrically connected to the battery unit and the control and calculation unit for measuring voltage, current and operation time in the battery group, and the energy regulation unit is used for the energy regulation unit And adjusting the amount of power required for equalizing the plurality of battery cells in the battery pack; and starting a equalization program to calculate and control the plurality of battery modules according to a certain voltage in the battery pack Switching sequence and opening time of a plurality of switches, and adjusting the battery capacity by the energy regulating unit so that the battery pack is waiting During a plurality of charging cycles of operation, the individual positive and negative voltage differences of the plurality of battery cells or a plurality of string battery cells consisting of the plurality of battery cells are less than a first allowable range when the constant current charging is converted to constant voltage charging and A certain charging cycle all enters the constant voltage charging phase. The battery pack voltage balancing method according to claim 11 of the patent application scope, The process further includes: matching a voltage weight coefficient or a power weight coefficient respectively according to a voltage difference or a power difference or a charging time difference of a first reference string battery core and a first equalization string battery core in the battery pack; Or the charging time weighting factor calculates the equalization time required to equalize the first equalizing string of cells. The battery voltage balancing method of claim 11, wherein the method further comprises: rotating the highest string voltage in the plurality of string battery groups. The battery voltage balancing method of claim 13, wherein the method further comprises: when the first string of cells in the plurality of string cells is reached in the charging cycle Discharging the first string of battery cells when the voltage is charged, so that the string voltage of the first string of cells in the next charging cycle when the second string of cells reaches the constant voltage charging set voltage is lower than the current charging The lowest string voltage in the cycle. The battery pack voltage balancing method of claim 14, wherein the method further comprises: averaging current values according to the energy regulation unit and the control and calculation unit for the plurality of string battery core groups The string voltage difference calculation determines the switching position and switching time of the plurality of switches in the off-grid array. The battery voltage balancing method of claim 15, wherein the method further comprises: performing the following judgment and operation according to the series voltage difference measurement results of the plurality of string battery groups: When the highest string voltage value in the plurality of string battery groups differs from the lowest string voltage value by more than a first differential pressure setting value, the first equalization operation time is calculated according to the control and calculation unit to turn on the switch. The switch corresponding to the current equalization program in the array is turned off when the time to be turned on reaches the first equalization operation time; when the highest string voltage value in the plurality of string battery groups is different from the lowest string voltage value Exceeding the first differential pressure setting value, selecting and turning on a switch in the switch array and maintaining a second equalization operation time, discharging a second string of battery cells in the plurality of string battery groups to a first ratio The amount of electricity, wherein the switches are selected in such a way that the plurality of strings of battery cells are alternately discharged in different charging cycles. The battery pack voltage balancing method of claim 16, wherein the method further comprises: calculating the first equalization operation time and a difference between the highest string voltage and the lowest string voltage in the current charging cycle and The product of the first weighting factor and a first equalization current are correlated. The battery voltage balancing method of claim 17, wherein the method further comprises: setting the first weight coefficient according to a difference between a highest string voltage and a lowest string voltage in the previous charging cycle and the current During the charging cycle, the difference between the two series of battery cells corresponding to the highest and lowest series voltages in the previous charging cycle at the end of the constant current charging is corrected. If the initial charging cycle is the first charging coefficient, the first weighting factor is A preset value. The battery voltage balancing method of claim 11, wherein the method further comprises: electrically powering all of the plurality of battery cells in a charging cycle Quantity adjustment. The battery voltage balancing method according to claim 19, wherein the method further comprises: when the voltage difference between the individual positive and negative electrodes in the plurality of string battery groups reaches the constant voltage in a constant current charging phase When charging the set voltage, the following operations are performed: after a first set time, the individual open circuit voltages of the plurality of string battery core groups are measured; and all the plurality of string battery core groups are calculated to start at the first set time The individual static voltage differences that are completed; and the equalization power required for the plurality of string battery core groups based on the aforementioned open circuit voltage and the static voltage difference.