JP2017212832A - Battery management device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle battery management device capable of reducing the charging time while reducing energy consumption due to useless cell balancing during charging a battery.SOLUTION: In order to generally fully charging plural battery cells during battery charging, the battery management device is configured to control the closing time of balancer resistance interrupting means, in a state of charge of each of the battery cells at a present point, based on the ratio between a current value (Iccn), which flows to a balancer circuit provided to each battery cell, and a current value (Ibn), which flows to the balancer circuit in a state that the balancer resistance interrupting means of the balancer circuit is in constant closing state.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a battery management apparatus using a cell balance method for equalizing each battery cell voltage of a battery pack.

In recent years, secondary batteries have come to be used as household or industrial emergency power supplies and electric vehicle drive power supplies. Since this secondary battery is limited in electromotive voltage and electric capacity, it is common to use a plurality of secondary batteries connected in series and parallel in accordance with the above-mentioned applications. A battery having such a structure is also referred to as an assembled battery or simply a battery pack. (Hereinafter referred to as a battery pack.) A battery constituting a unit constituting the battery pack is referred to as a battery cell.
By the way, when the battery pack is used for a long time or when some of the battery cells are replaced with new batteries, the capacity varies among the battery cells. When this capacity variation occurs, a specific battery cell is overdischarged or overcharged when the battery pack is charged or discharged. As a result, the capacity of the battery pack is reduced, the battery pack is deteriorated, and the life is shortened.
In order to eliminate such variation in the capacity of the battery pack, conventionally, the balance control of the battery cells is performed so that all the battery packs are fully charged when the battery pack is fully charged. (See Patent Document 1)

Japanese Patent No. 3882663

However, in the cell balance control method of Patent Document 1 as described above, the cell balance resistance installed in each battery cell is controlled using the lowest voltage among the battery cells as the cell balance target value. Since the battery cells have different capacities as described above, the charging rate of each battery cell during charging does not change uniformly. That is, when the charge amount changes, the battery cell having the lowest voltage also changes.
Therefore, the battery cell that has the lowest voltage during charging changes with respect to the battery cell that has been the lowest voltage before charging, so cell balance control is performed even for battery cells that do not need to be cell-balanced. There is a problem in that the charging energy is consumed and the charging time is extended.

Such a conventional cell balance control operation will be described based on the timing charts of FIGS. In order to make the operation easy to understand, a case will be described in which two battery cells A and B are connected in series as a battery pack.
Here, the characteristics of the two battery cells A and B are
Capacity of battery cell A> Capacity of battery cell B,
The voltage Va1 between the terminals of the battery cell A before charging> the voltage Vb1 between the terminals of the battery cell B,
And

  First, when the cell balance control is not performed, as shown in FIG. 13, since the capacity of the battery cell A is larger than the capacity of the battery cell B, the charging rate of the battery cell B is faster than that of the battery cell A as charging progresses. To increase. In other words, the voltage between the terminals of the battery cell B rises faster than the battery cell A. At the time t1, the voltage between the terminals of the battery cell A and the voltage between the terminals of the battery cell B become the same V2, and then the voltage between the terminals of the battery cell A becomes smaller than the voltage between the terminals of the battery cell B. Next, at time t2, the voltage between the terminals of the battery cell B first reaches the full charge voltage (here, 4.1V), and the battery cell A stops charging without being fully charged. become.

  In order to solve such an event, in Patent Document 1, as shown in FIG. 14, the voltage between the terminals of the battery cell A is larger than the voltage between the terminals of the battery cell B from the start of charging to time t3, as shown in FIG. The cell balance control of the battery cell A is performed with the cell balance target voltage being the same as the voltage across the terminals of the battery cell B. When the cell balancer control is performed in the battery cell A, the charging current flows to the balancer. Therefore, the degree of charging, that is, the degree of increase in the voltage between terminals is lower than when the cell balancer control is not performed.

Next, at time t3, the voltage between the terminals of the battery cell A and the voltage between the terminals of the battery cell B are the same V3. After the time t3, the cell balance target voltage is the same as the voltage between the terminals of the battery cell A. B cell balance control is performed.
Thereafter, at time t4, the battery cells A and B are fully charged, and charging is stopped. However, in this case, it is understood that cell balance control is performed for the battery cell A that does not require cell balance, and charging energy is consumed due to extension of charge and unnecessary cell balance.

  The present invention has been made to solve the above-described problems. Even when the battery cell capacity varies, the battery pack can be charged while extending the charge and consuming unnecessary charging energy. An object of the present invention is to provide a battery management device that can suppress variations in voltage between terminals of each battery cell when completed.

  The battery management device according to the present invention includes a cell voltage detection means for detecting a voltage (Vn) between terminals in a plurality of battery cells constituting the battery pack, a current detection means for detecting a charge / discharge current of the battery pack, Cell remaining charge amount calculating means for calculating a remaining charge amount (Qremn) of each battery cell based on a charge state of the battery pack, and a remaining value for calculating a maximum value (Qrem_max) from the remaining charge amount (Qremn) of each battery cell A charge amount maximum value calculating means, a cell target charge rate calculating means for calculating a target charge rate (SOC_tgn) at which the remaining charge amount of each battery cell becomes a maximum value (Qrem_max), and each of the cell target charge rate calculating means Calculate target voltage (Vtgn) from target charge rate (SOC_tgn) of battery cell Cell target voltage calculation means, and balancer drive for determining whether or not to perform balancer drive according to the difference between the terminal voltage (Vn) by the cell voltage detection means and the target voltage (Vtgn) by the cell target voltage calculation means Determining means, and configured to execute individual cell balance control for each of the battery cells based on the determination result of the balancer drive determining means.

  According to the battery management device of the present invention, even when there is a variation in capacity between battery cells, such as when the battery pack is used for a long time or when some battery cells are replaced with new batteries, the charge state of each battery cell By setting the target cell voltage according to the battery voltage, it is possible to suppress variations in the voltage between terminals of each battery cell when the charging of the battery pack is completed.

It is a conceptual diagram which shows the electric vehicle to which the battery management apparatus which concerns on Embodiment 1 of this invention is applied. It is a block diagram which shows the specific structure of the battery management apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the workflow explaining operation | movement of the battery management apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the workflow for demonstrating the cell voltage value storage operation | movement in FIG. It is a figure which shows the workflow for demonstrating the electric current value storage operation | movement in FIG. It is a figure which shows the workflow for demonstrating the cell capacity | capacitance estimation operation | movement in FIG. It is a figure which shows the workflow for demonstrating calculation operation | movement of each cell remaining charge amount in FIG. It is a figure which shows the workflow for demonstrating the calculation operation | movement of the remaining charge amount maximum value in FIG. It is a figure which shows the workflow for demonstrating the calculation operation | movement of each cell target charging rate in FIG. It is a figure which shows the workflow for demonstrating the calculation operation | movement of each cell target voltage in FIG. It is a figure which shows the workflow for demonstrating the balancer drive determination operation | movement in FIG. It is a schematic diagram showing the relationship between target SOC and target voltage. It is a timing chart for demonstrating operation | movement at the time of charging, without implementing cell balance control. It is a timing chart for demonstrating the operation | movement at the time of prior art adaptation. It is a timing chart for demonstrating the operation | movement in Embodiment 1 of this invention. It is a principal part block diagram which shows the structure of the battery management apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the workflow explaining operation | movement of the battery management apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the workflow for demonstrating the estimation operation | movement of the charging time in FIG. It is a figure which shows the workflow for demonstrating the estimation operation | movement of each cell internal resistance in FIG. It is a figure which shows the workflow for demonstrating the calculation operation | movement of each cell full charge consumption charge amount in FIG. It is a figure which shows the workflow for demonstrating calculation operation | movement of the consumption charging current per cell unit time in FIG. It is a figure which shows the workflow for demonstrating calculation operation | movement of each cell balancer consumption charging current in FIG. It is a figure which shows the workflow for demonstrating the calculation operation | movement of each cell balancer drive ratio in FIG. It is a timing chart for demonstrating the consumption charging current per unit time in Embodiment 1 of this invention. It is a timing chart for demonstrating the operation | movement in Embodiment 2 of this invention.

Embodiment 1 FIG.
Hereinafter, the present invention will be described with reference to the drawings.
1 is a schematic diagram showing an electric vehicle to which a battery management device according to Embodiment 1 of the present invention is applied, and FIG. 2 is a block diagram showing a specific configuration of the battery management device in FIG.

  In FIG. 1, an electric vehicle 100 supplies a power to the vehicle control device 101 that controls driving and charging of the electric vehicle, a driving motor 102 that drives wheels, an inverter 103 that controls the driving motor, and the inverter 103. A battery pack 104 for monitoring the battery pack 104, and a battery charger 106 for charging the battery pack 104 from the outside.

Here, the vehicle control apparatus 101 makes a drive request for the motor 102 to the inverter 103 in order to run the electric vehicle, and the inverter 103 drives the motor 102 using the electric power of the battery pack 104. The battery pack 104 is monitored by the battery management device 105, and the battery state by the battery management device 105 is sent to the vehicle control device 101. The vehicle control device 101 realizes traveling control according to the battery state. Is configured to do.
Furthermore, the vehicle control device 101 instructs the charger 106 to charge the battery pack 104 in response to a charge request from the outside, and controls charging to the battery pack 104.

FIG. 2 shows a specific configuration of the battery management apparatus in FIG. 1. In FIG. 2, the vehicle control apparatus 101 includes a microcomputer (hereinafter referred to as a microcomputer) 201 that controls running and charging. The microcomputer 201 is provided with charge control mode determination means 202 for performing charge control.
The battery pack 104 includes a plurality of battery cells 301a, 301b,. Since the output voltages of the battery cells 301a, 301b,... 301n are low, the battery pack 104 is configured so that the output voltage necessary for driving the vehicle can be obtained by connecting them in series. The battery pack 104 is connected to current detection means 306 that detects the charge / discharge current of the battery pack 104.

  Further, the battery management device 105 adjusts the cell voltages of the battery cells 301a, 301b,... 301n and the cell voltages of the battery cells 301a, 301b,. , And a microcomputer 401 that performs cell balance control, and is configured to monitor cell voltages of the battery cells 301a, 301b,... 301n, and to perform cell balance control that equalizes the cell voltages of all battery cells. ing.

Here, the balancer 302 is configured by connecting a series circuit of a balancer resistor 304 and a balancer resistor interrupting means 305 such as a transistor between each of the battery cells 301a, 301b,... 301n, and in accordance with a cell balance control instruction from the microcomputer 401. Take control.
Further, the cell voltage detection means 303a, 303b,... 303n are connected in parallel between the battery cells 301a, 301b,... 301n, and the microcomputer detects the voltage between the terminals of each battery cell 301a, 301b,. 401 is output.

The microcomputer 401 is connected to the vehicle control device 101, which is a host control device, through communication, determines whether or not to perform cell balance control based on information from the vehicle control device 101, and determines cell voltage detection means 303a, 303b, ... the balancer 302 is driven and controlled from the voltages of the battery cells 301a, 301b, ... 301n detected by 303n.
Specifically, the microcomputer 401 includes cell voltage value storage means 402 for storing the cell voltages from the cell voltage detection means 303a, 303b,... 303n in a RAM (Random Access Memory) for each battery cell, and the battery pack 104. Current value storage means 403 for storing the current value from the current detection means 306 for detecting the charge / discharge current in the RAM, cell capacity estimation means 404 for estimating the capacity of each battery cell, and charge control mode determination of the vehicle control device 101 A cell balance control execution determination unit 405 that determines whether or not to perform cell balance control based on information from the unit 202 and a cell balance control unit 406 that performs cell balance control are provided.

  This cell balance control means 406 is based on the current value from the current value storage means 403, the capacity of each battery cell from the cell capacity estimation means 404, and the cell voltage from the cell voltage value storage means 402. From each cell remaining charge amount calculating means 501 for calculating the remaining charge amount, the remaining charge amount maximum value calculating means 502 for calculating the maximum value from each cell remaining charge amount, the remaining charge amount maximum value and the capacity of each battery cell Each cell target charge rate calculation means 503 for calculating each cell target charge rate, each cell target voltage calculation means 504 for calculating each cell target voltage from each cell target charge rate, and a balancer based on each cell voltage and each cell target voltage Balancer drive determination means 505 for determining drive is provided.

Next, the operation of the battery management device configured as described above will be described.
First, the cell voltage detection means 303a, 303b,... 303n of the battery management apparatus 105 outputs the cell voltages read from the connected battery cells 301a, 301b,. Based on this output, the cell voltage value storage means 402 stores the cell voltages of the battery cells 301a, 301b,... 301n at regular intervals, and collects the cell voltages of the battery cells 301a, 301b,. It outputs to the drive determination means 505.
In addition, the cell capacity estimation means 404 estimates the capacity of each battery cell 301a, 301b,... 301n and outputs the estimated capacity to the cell balance control means 406.
As a method for estimating the battery cell capacity, for example, a method described in Japanese Patent Application Laid-Open No. 2012-181066 is known.

On the other hand, when a power source (for example, a commercial AC 200V power source) is connected to the charger 106, a charger connection signal is output to the charging control mode determination unit 202 of the vehicle control device 101.
When this charger connection signal is input to charge control mode determination means 202, it is determined that the vehicle is in a charging operation, and a charge control mode determination signal is output to cell balance control execution determination means 405 of battery management device 105. When the charge control mode determination signal is input, the cell balance control execution determination unit 405 determines that the cell balance control can be performed, and outputs a cell balance control execution enable signal to the cell balance control unit 406. The cell balance control means 406 is operated.

  In this cell balance control means 406, each cell remaining charge calculation means 501 is based on the current value output from the current value storage means 403 and the capacity of each battery cell output from the cell capacity estimation means 404. The cell charge rate is obtained, and the remaining charge amount until the battery cells 301a, 301b,... 301n are fully charged is calculated based on the charge rate, and the remaining charge amount is calculated as the remaining charge amount of each cell. Output to 502.

The remaining charge amount maximum value calculation means 502 calculates the maximum value based on each cell remaining charge amount output from each cell remaining charge amount calculation means 501, and uses this as the remaining charge amount maximum value for each cell target charge rate. Output to the calculation means 503.
Furthermore, each cell target charge rate calculation means 503 is based on the capacity of each battery cell output from the cell capacity estimation means 404 and the remaining charge amount maximum value output from the remaining charge amount maximum value calculation means 502. The target charging rate of the battery cells 301a, 301b,... 301n is calculated and output to each cell target voltage calculation means 504 as each cell target charging rate.

Each cell target voltage calculation means 504 calculates the target voltage of each battery cell by referring to the table data as shown in FIG. 12 from each cell target charge rate output from each cell target charge rate calculation means 503. Is output to the balancer drive determination means 505 as each cell target voltage.
The table data shown in FIG. 12 is a two-dimensional table in which the x-axis data is the charging rate and the y-axis data is the cell target voltage, and the y-axis data is preset according to the x-axis data. .

  Next, the balancer drive determination unit 505 determines, for each battery cell, the cell voltage of each battery cell output from the cell voltage value storage unit 402 and the target voltage of each battery cell output from each cell target voltage calculation unit 504. A voltage difference is obtained, and if this voltage difference is equal to or greater than the threshold value, a balancer drive signal is output to the balancer 302. The output balancer driving signal turns on the balancer resistance interrupting means 305 of the corresponding cell in the balancer 302 and executes cell balance control.

Next, a method for calculating the target voltage of each of the battery cells 301a, 301b,.
Here, if each battery cell 301a, 301b,... 301n is each battery cell n, the current value flowing through the battery cell n is I [A], and the capacity of the battery cell n is Cpn [Ah], the battery cell n is charged. The rate SOCn [%] is obtained from the time integration of the current value I (t) [A] and is expressed by the following equation.

また、バッテリーセルｎの残充電量Ｑｒｅｍｎ［Ａｈ］は、次式で表される。

Further, the remaining charge amount Qremn [Ah] of the battery cell n is expressed by the following equation.

さらに、残充電量最大値Ｑｒｅｍ＿ｍａｘ［Ａｈ］は、次式で表される。

Furthermore, the remaining charge amount maximum value Qrem_max [Ah] is expressed by the following equation.

  By the way, in the prior art, the remaining charge amount of the battery cell, which is the lowest cell voltage, does not always become the maximum depending on the battery capacity. The occurrence of consumption was a problem. In order to eliminate this useless cell balance, cell balance control may be performed so that the remaining charge amount is the same in all battery cells, and a battery pack in which a plurality of battery cells 301a, 301b,. In 104, since the charge amount is equally added to all the battery cells, the remaining charge amount target may be set to the remaining charge amount maximum value Qrem_max.

Next, a method for calculating the target voltage Vtgn in the battery cell n from the maximum remaining charge amount Qrem_max will be described.
First, when the battery cell n is charged to the maximum remaining charge amount Qrem_max [Ah], the target charge rate SOCtgn [%] that is fully charged is expressed by the following equation.

  Further, the target voltage Vtgn [V] in each battery cell n can be obtained by the following equation using the processing map (SOC) referring to the table data shown in FIG.

Next, the cell balance control operation in the first embodiment will be described using the workflows shown in FIGS.
FIG. 3 is a workflow for explaining the operation of the battery management apparatus 105. This operation is executed at predetermined time intervals set in the microcomputer 401 or the like.
First, in step S1, the cell voltage acquired from the cell voltage detection unit 303 is stored in the RAM sequentially for each cell by the cell voltage value storage unit 210.
Next, in step S <b> 2, the charge / discharge current of the battery pack 104 acquired from the current detection unit 306 is stored in the current value storage unit 403.

Next, in step S3, the capacity of each battery cell is estimated by the cell capacity estimating means 404 and stored in the RAM.
As a method for estimating the cell capacity, for example, a method described in Japanese Patent Application Laid-Open No. 2012-181066 is known.

Next, in step S <b> 4, it is determined whether to perform cell balance control based on information from the charging control mode determination unit 202 of the vehicle control device 101. Specifically, it is determined whether or not the charger 106 is performing a charging operation. If the charging operation is being performed, it is determined that cell balance control is necessary. If the charging operation is not being performed, the cell balance control is performed. It is determined that it is unnecessary.
If it is determined that cell balance control is not necessary, the process proceeds to step S10 and the process is terminated. On the other hand, if it is determined that the cell balance control is necessary, the process proceeds to step S5, where the cell voltage of each battery cell 301a, 301b,... 301n stored in step S1 and each battery cell 301a, 301b,. Each cell charge rate is calculated from the capacity of 301n, and each cell remaining charge amount is calculated from each cell charge rate.

Next, in step S6, the remaining charge amount maximum value is calculated from each cell remaining charge amount. In step S7, each cell target charge rate that is fully charged when each battery cell is charged with the remaining charge amount maximum value is determined. Calculated from the maximum remaining charge.
Next, in step S8, each cell target voltage is calculated based on each cell target charging rate. Finally, in step S9, the cell voltage of each battery cell stored in step S1 and each calculated in step S8 are calculated. It is determined whether or not the balancer control is driven based on the cell target voltage value.

Next, details of steps S1 to S3 and steps S5 to S9 in FIG. 3 will be described.
FIG. 4 is a workflow diagram showing details of step S1 (balancer drive control).
In step S11, the cell voltage detected by the cell voltage detection means 303 is read into the microcomputer 401 via the communication means or the like, and in step S12, the read cell voltage is stored in the target cell voltage storage RAM. The process of step S1 is performed by the cell voltage value storage unit 402.

FIG. 5 is a workflow diagram showing details of step S2 (current value storage processing).
In step S21, the charge / discharge current of the battery pack 104 detected by the current detection means 306 via the communication means or the like is read by the microcomputer 401, and in step S22, the read current is stored in the current value storage RAM. Note that the current value storage means 403 performs the processing in step S2.

FIG. 6 is a workflow diagram illustrating details of step S3 (each cell capacity calculation).
In step S31, the capacity of each battery cell n is estimated based on various information of each battery cell n, and stored in each cell capacity storage RAM in step S32. The process of step S3 is performed by the cell capacity estimation unit 404.

FIG. 7 is a workflow diagram showing details of step S5 (calculation of each cell remaining charge amount).
First, in step S51, the current value I and each cell capacity CPn are input, and the charging rate SOCn of each battery cell n is obtained based on (Equation 1). Next, in step S52, the charging rate SOCn of each battery cell n is obtained. Based on (Equation 2), the remaining charge amount Qremn of each battery cell n is calculated. In step S53, the calculated remaining charge amount Qremn of each battery cell n is stored in each cell remaining charge amount RAM. In addition, the process of step S5 is performed by each cell remaining charge calculation means 501.

FIG. 8 is a workflow diagram showing details of step S6 (calculation of maximum remaining charge amount).
In step S61, the remaining charge maximum value Qrem_max is calculated from each cell remaining charge amount Qremn based on (Equation 3), and in step S62, the maximum value is stored in the remaining charge amount maximum value RAM. The process of step S6 is performed by the remaining charge maximum value calculation unit 502.

FIG. 9 is a workflow diagram showing details of Step S7 (each cell target charging rate calculation).
In step S71, each cell capacity CPn and maximum remaining charge amount Qrem_max are input, and a target charge rate SOCtgn of each battery cell n is calculated based on (Equation 4). In step S72, the target charge of each battery cell n is calculated. The rate SOCtgn is stored in each cell target charge rate RAM. In addition, the process of step S7 is performed by each cell target charge rate calculation means 503.

FIG. 10 is a workflow diagram showing details of step S8 (each cell target voltage calculation).
In step S81, referring to the table data shown in FIG. 12, the target voltage Vtgn of each battery cell n is calculated from each cell target charge rate SOCtgn. Thereafter, in step S82, the target voltage Vtgn of each battery cell n is stored in each cell target voltage RAM. The process in step S8 is performed by each cell target voltage calculation unit 504 in FIG.

FIG. 11 is a workflow diagram showing details of step S9 (balancer drive determination).
First, in step S91, the difference between the cell voltage Vn [V] of each battery cell n and the target voltage Vtgn of each battery cell n is calculated as the balancer drive determination value ΔVn [V] of each battery cell n. The balancer drive determination value ΔVn of each battery cell n is calculated based on the following equation.

Next, in step S92, balancer drive determination is performed based on the balancer drive determination value ΔVn of each battery cell n calculated in step S91. In step S92, when the balancer drive determination value ΔVn of each battery cell n is larger than 0, the process proceeds to step S93, and the balancer drive start instruction for the battery cell n is turned on. When the balancer driving start instruction for the battery cell n is turned on, the balancer resistance interrupting means 305 including the switching element of the battery cell n is turned on to perform balancer control.
On the other hand, when the balancer drive determination value ΔVn is 0 or less, the process proceeds to step S94, and the balancer drive start instruction for the battery cell n is turned off. When the balancer drive start instruction for the battery cell n is turned off, the balancer resistance interrupting means 305 for the battery cell n is turned off and the balancer control is stopped. The process of step S9 is performed by the balancer drive determination unit 505.

Next, the above processing will be described based on the timing chart shown in FIG.
15A shows the remaining charge amount of specific battery cells A and B from the start of charging to the end of charging, FIG. 15B shows the target charging rate of battery cells A and B, and FIG. The voltage between the terminals of the cells A and B and the target voltage, FIG. 15D, shows the balancer driving state of the battery cells A and B.
Here, the voltage between the terminals of the battery cell A before charging is Va1, the charging rate SOCA is 60.0 [%], the capacity CpA is 100 [Ah], the voltage between the terminals of the battery cell B is Vb1, and the charging rate SOCB is 40. Description will be made assuming that [%] and the capacitance CpB are 50 [Ah]. The relationship between the terminal voltages Va1 and Vb1 is Va1> Vb1 because SOCA> SOCB. Further, it is assumed that the vehicle is in a charging operation state, execution determination of balancer drive control is established, and steps S5 to S9 are executed.

First, the remaining charge amount, the target charge rate, and the target voltage of the battery cells A and B at the start of charging will be described.
First, in step S5, the remaining charge amounts QremA and QremB of the battery cells A and B are calculated, and QremA = 40 [Ah] and QremB = 30 [Ah] are obtained from (Equation 2) from the above conditions.

Next, in step S6, the remaining charge amount maximum value is calculated. Here, the remaining charge amount maximum value Qrem_max = QremA = 40 [Ah].

Next, in step S7, target charge rates of the battery cells A and B are calculated. From the above conditions, the target charging rate SOCtgA = SOCA = 60 [%] of the battery cell A and the target charging rate SOCtgB = 20 [%] of the battery cell B are obtained from Equation 4.

  Next, in step S8, the target voltage VtgA of the battery cell A and the target voltage VtgB of the battery cell B are calculated. Here, while the remaining charge amount QremA of the battery cell A is equal to the remaining charge amount maximum value Qrem_max, the charge rate SOCA of the battery cell A matches the target charge rate SOCtgA. As shown in FIG. 12, since the charging rate SOC and the inter-terminal voltage are in a unique relationship, it can be seen that the inter-terminal voltage VA of the battery cell A matches the target voltage VtgA.

On the other hand, in the battery cell B, the remaining charge amount QremB is smaller than the maximum remaining charge amount Qrem_max. Vb1 is larger than the target voltage VtgB.
Thereafter, charging is performed. During charging, Steps S5 to S9 are repeatedly executed, and the remaining charge amount, the target charge rate, and the target voltage of the battery cells A and B are updated.

FIG. 15 (a) shows the change in the remaining charge amount of the battery cells A and B from the start of charging to the end of charging, FIG. 15 (b) shows the change in the target charging rate, and FIG. FIG. 15D shows the balancer driving state of the battery cells A and B in FIG.
During charging, the remaining charge amount QremA of the battery cell A and the remaining charge amount maximum value Qrem_max match, that is, the voltage VA between the terminals of the battery cell A and the target voltage VtgA of the battery cell A match. 302 is not driven and cell balancing is not performed.

  On the other hand, since the remaining charge amount QremB of the battery cell B is smaller than the remaining charge amount maximum value Qrem_max, the charge rate SOCB of the battery cell B is larger than the target charge rate SOCtgB of the battery cell B, that is, the battery cell B The inter-terminal voltage Vb becomes larger than the target voltage VtgB of the battery cell B, the balancer 302 of the battery cell B is driven, and the cell balance is executed. At time t5, the remaining charge amounts of the battery cells A and B coincide with each other, and the balancer 302 of the battery cell B stops. Thereafter, at time t6, the battery is fully charged and charging is completed.

  As described above, in the operation from the start of charging to the end of charging, the battery cell B is fully charged without charging the battery cell A with 40 [Ah] which is the remaining charge amount QremA of the battery cell A. I can see that That is, the cell balance of the battery cell A shown in FIG. 14 is not performed, so that consumption of useless charging energy can be suppressed and the charging time can be shortened.

Embodiment 2. FIG.
In the above-described first embodiment, the balancer 302 of cells other than the maximum remaining charge amount Qrem_max is driven until the remaining charge amount of each cell becomes the same. In this case, the balancer 302 is driven per unit time. Since the cell balance control is performed in a state where the amount of charge to be consumed is maximum, the balancer resistor 304 generates heat and deteriorates, causing a failure. Further, in the case where the remaining charge amount of each cell becomes the same during charging (time t5 in FIG. 15), when charging is interrupted, the unit of remaining charge amount of each cell becomes the same when fully charged. The amount of charge consumed by the charging balancer resistor 304 per hour becomes excessive.
In order to solve such a problem, in the second embodiment of the present invention, the balancer 302 of the cells other than the maximum remaining charge amount Qrem_max is intermittently driven so that the remaining charge amount of each cell becomes the same when fully charged. It is a thing.

First, each cell remaining charge amount, each cell full charge consumption charge amount, each cell unit time consumption charge current, and the balancer drive state in the first embodiment will be described with reference to FIG. 24 which is a timing chart.
24A shows the voltage between the terminals of the battery cells A and B and the target voltage from the start of charging to the end of charging, FIG. 24B shows the balancer driving state of the battery cells A and B, and FIG. FIG. 24 (d) shows the charging current consumed per unit time of the battery cells A and B. FIG.

  Here, the full charge consumption charge amount indicates the charge amount consumed before full charge. The charging current consumption per unit time indicates the charging amount consumed per unit time, and is equal to the gradient of the full charging consumption charging amount. Further, the terminal voltage, the charging rate, and the capacity of each battery cell at the start of charging (t = 0) are the same as those in the first embodiment.

  First, at the charging start time t = 0, the voltage Vb1 between the terminals of the battery cell B becomes higher than the target voltage VtgB, and the balancer 302 of the battery cell B is turned on. Thereafter, the balancer 302 of the battery cell B is turned on until the time t5 when the voltage Vb1 between the terminals of the battery cell B becomes equal to the target voltage VtgB, and the current always flows to the balancer 302 of the battery cell B. Is consumed. Thereafter, at time t5, the remaining charge amount of the battery cell A and the remaining charge amount of the battery cell B become the same, and the full charge consumption charge amount of the battery cell B becomes zero. Furthermore, the inter-terminal voltage Vb1 of the battery cell B becomes the same as the target voltage VtgB, and the balancer 302 stops.

  Here, when the charging is stopped between the charging start time (t = 0) and the time (t = 5), the unit time of the battery cell B is compared with the case where the full charge consumption charge amount becomes zero due to the full charge. The charging current consumption per hit increases. That is, the charge amount of the battery cell B is consumed excessively. In addition, since an excessive current flows through the balancer resistor 304, the balancer resistor 304 generates heat and promotes deterioration and failure.

In view of such a problem, the second embodiment is characterized in that the balancer 302 is intermittently driven so that the charge consumption charge amount becomes zero when fully charged.
FIG. 16 is a principal block diagram showing a specific configuration of the battery management device according to the second embodiment of the present invention. FIG. 16 shows the principal configuration of the microcomputer 401 in the battery management device 105, and the vehicle control device 101, battery The configurations of the pack 104, the balancer 302, and the like are the same as those in FIG.

In the microcomputer 401, the cell voltage value storage unit 402, the current value storage unit 403, the cell capacity estimation unit 404, and the cell balance control execution determination unit 405 are substantially the same as the configuration described in the first embodiment. is there. The microcomputer 401 is provided with charging time estimating means 511 for estimating the charging time Tchg, which is the time until full charge, and each cell internal resistance estimating means 512 for estimating the internal resistance Rinn of each cell.
Further, the cell balance control means 406 of the microcomputer 401 includes each cell remaining charge amount calculating means 501, remaining charge maximum value calculating means 502, each cell target charge rate calculating means 503, and each cell target voltage calculating means 504. In addition to the following configuration has been added.

  That is, each cell that calculates each cell full charge consumption charge amount Qcn from each cell remaining charge amount Qremn from each cell remaining charge amount calculation means 501 and the remaining charge amount maximum value Qrem_max from the remaining charge amount maximum value calculation means 502 A full charge / consumption charge amount calculation means 506, a consumption charge current calculation means 507 for each cell unit time for calculating a consumption charge current Iccn per unit time based on the charge time Tchg and each cell full charge consumption charge amount Qcn, and current value storage Each cell balancer consumed by the current value I flowing in the battery cell n obtained from the means 403, the cell voltage Vn obtained from the cell voltage value storage means 402, each cell internal resistance Rinn, and the balancer resistance value Rb recorded as an eigenvalue inside the microcomputer Each cell balancer consumption charging current calculation means 508 for calculating the charging current Ibn, Each cell balancer drive ratio calculation means 509 for calculating each cell balancer drive ratio Duty from each cell balancer consumption charge current Iccn, each cell balancer consumption charge current Ibn, cell voltage Vn and each cell target voltage Vtgn, and each cell balancer Balancer driving means 510 for driving the balancer according to the driving ratio Dutyn is provided.

Next, the operation of such a battery management device will be described.
First, the charging time estimation means 511 estimates the time Tchg until full charge, and outputs it to the consumption charge current calculation means 507 per unit cell time. Further, each cell internal resistance estimation means 512 estimates each cell internal resistance Rinn and outputs it to each cell balancer consumption charging current calculation means 508. A charging time estimation method is known, for example, in Japanese Patent No. 5742999, and a cell internal resistance estimation method is known, for example, in Japanese Patent Laid-Open No. 2014-6245.

On the other hand, each cell full charge consumption charge amount calculation unit 506 includes a remaining charge amount Qrem_max output from the remaining charge amount maximum value calculation unit 502 and each cell remaining charge amount Qremn calculated by each cell remaining charge amount calculation unit 501. From each difference, each cell full charge consumption charge amount Qcn, which is a charge amount to be consumed before full charge of each cell, is calculated and output to the consumption charge current calculation means 507 for each cell unit time.
In response to the output of the charging time Tchg and each cell full charge consumption charge amount Qcn, each cell unit time consumption charge current calculation means 507 performs each charge to consume each cell full charge consumption charge amount Qcn in full charge. The consumption charge current Iccn per unit time of the cell is calculated and output to each cell balancer drive ratio calculation means 509.

  Next, each cell balancer consumption charging current calculation means 508 calculates each cell balancer consumption charging current Ibn from the current value I, the cell voltage Vn, each cell internal resistance Rinn, and the balancer resistance value Rb recorded inside the microcomputer. And output to each cell balancer drive ratio calculation means 509. Each cell balancer drive ratio calculating means 509 calculates the ratio of the consumption charge current Iccn per cell unit time and the cell balancer consumption charge current Ibn for each cell balancer when the cell voltage Vn is equal to or higher than each cell target voltage Vtgn. If the cell voltage Vn is less than each cell target voltage Vtgn, the cell balancer drive ratio Duty is set to zero and output to the balancer driving means 510. In response to this output, the balancer driving means 510 repeatedly disconnects and connects the balancer resistance interrupting means 305 at a predetermined cycle according to each cell balancer driving ratio Dutyn.

Next, a method for calculating each cell balancer drive ratio Dutyn will be described.
First, the amount of charge that should be consumed by the balancer before full charge in each battery cell n is obtained. The full charge consumption charge amount Qcn [Ah] in each battery cell n is the difference between the remaining charge amount Qremn [Ah] and the remaining charge amount maximum value Qrem_max [Ah], and is expressed by the following equation.

  Next, in order to consume the full charge consumption charge amount in the balancer 302 in the time required for each battery cell n to be fully charged, that is, the time from the start of charge to the end of charge, the current to be supplied to the balancer 302 is calculated per unit time. The charging current consumption Iccn [A] is calculated. Here, assuming that the charging time is Tchg [hr], the charging current consumption Iccn [A] per cell unit time from each cell full charge consumption charge amount Qcn is expressed by the following equation.

Next, the amount of charge that the balancer 302 can consume per unit time is obtained.
First, the current value Ibn [A] that flows through the balancer 302 in a state where the balancer resistance interrupting means 305 of the balancer 302 is closed in the current charging state of each battery cell n is obtained.
Although not shown in FIG. 16, the battery cell n has an internal resistance, that is, a resistance of a series component with respect to the voltage source, and a parallel circuit with the balancer resistance 304 is configured. Therefore, if the current flowing through the battery cell n is I [A], each cell voltage is Vn [V], each cell internal resistance is Rinn [Ω], and the balancer resistance is Rb [Ω], the balancer of each battery cell n Current Ibn [A] flowing through 302 is expressed by the following equation using Kirchhoff's first law and the principle of superposition.

したがって、バランサ３０２が単位時間当たりに消費できる充電電流は、Ｉｂｎ［Ａ］となる。また、バランサ駆動割合Ｄｕｔｙｎ［％］は、各セル単位時間当り消費充電電流Ｉｃｃｎ［Ａ］と各セルバランサ消費充電電流Ｉｂｎ［Ａ］との割合であり、次式で表される。

Therefore, the charging current that can be consumed by the balancer 302 per unit time is Ibn [A]. The balancer drive ratio Dutyn [%] is a ratio between each cell unit charge consumption current Iccn [A] and each cell balancer consumption charge current Ibn [A], and is expressed by the following equation.

なお、バランサ駆動割合Ｄｕｔｙｎ［％］が１００％以上である場合は、１００％とする。また、セル電圧Ｖｎが前記目標セル電圧Ｖｔｇｎ未満である場合は、実施の形態１で説明したように、充電時間の延長や無駄な充電量消費の発生となるため、バランサ駆動割合Ｄｕｔｙｎ［％］を０％とする。

In addition, when the balancer drive ratio Dutyn [%] is 100% or more, it is set to 100%. Further, when the cell voltage Vn is less than the target cell voltage Vtgn, as described in the first embodiment, the charging time is extended and useless charge consumption occurs, so the balancer drive ratio Dutyn [%] Is 0%.

Next, the cell balance control operation in the second embodiment will be described based on the workflow shown in FIG.
FIG. 17 shows a workflow executed by the battery management apparatus 105, and the processing here is executed every predetermined time.
Here, steps S1 to S3 are the same as the processing in the first embodiment, and a description thereof will be omitted.
In step S11 following step S3, the charging time is estimated and stored in the RAM. In step S12, the internal resistance of each battery cell n is estimated and stored in the RAM. A charging time estimation method and a cell internal resistance estimation method are known, for example, from Japanese Patent No. 5742999 and Japanese Patent Application Laid-Open No. 2014-6245.

Next, if it is determined in step S4 that the cell balance control calculation needs to be performed, the process proceeds to step S5. If it is determined that the cell balance control calculation is not necessary, the process proceeds to step S10, and the process ends. Steps S5 to S8 subsequent to step S4 are the same as those in the first embodiment, and a description thereof will be omitted.
In step S13 after receiving the process of step S8, the full charge consumption charge amount is calculated from the remaining charge amount of each battery cell n calculated in step S5 and the maximum remaining charge amount calculated in step S6.

Next, in step S14, the charging current consumed per cell unit time is calculated from the charging time calculated in step S11 and the full charge consumption amount of each cell calculated in step S13.
Thereafter, in step S15, each cell balancer consumption is calculated based on the cell voltage stored in step S1, the current value stored in step S2, each cell internal resistance calculated in step S12, and the balancer resistance recorded in advance in the microcomputer 401. Calculate the charging current.
In step S16, each cell unit consumption charge current calculated in step S14, each cell balancer consumption charge current calculated in step S15, the cell voltage of each battery cell n stored in step S1, and in step S8. Each cell balancer drive ratio is calculated from each calculated cell target voltage.

Next, details of the processing in steps S11 to S16 will be described with reference to FIGS.
FIG. 18 is a workflow diagram showing details of step S11 (charge time estimation).
First, in step S111, the charging time is estimated based on various information of each battery cell, and stored in the charging time storage RAM in step S112. The process in step S11 is performed by the charging time estimation unit 511.
FIG. 19 is a workflow diagram showing details of step S12 (cell internal resistance estimation).
In step S121, the internal resistance of each battery cell is estimated based on various information of each battery cell, and stored in each cell internal resistance storage RAM in step S122. Note that the processing in step S12 is performed by the cell internal resistance estimation means 512.

Next, the cell balance control calculation performed in steps S13 to S16 will be described.
FIG. 20 is a workflow diagram showing details of step S13 (calculation of each cell full charge consumption charge amount).
In step S131, each cell remaining charge amount Qremn and the remaining charge amount maximum value Qrem_max are input, and the cell full charge consumption charge amount Qcn of each battery cell is calculated based on (Equation 7). In subsequent step S132, the cell full charge consumption charge amount Qcn of each battery cell n is stored in each cell full charge consumption charge amount RAM. In addition, the process of step S13 is performed by each cell full charge consumption charge amount calculation means 506.

FIG. 21 is a workflow diagram showing details of step S14 (calculation of consumption charge current per cell unit time).
In step S141, as the charging time Tchg and each cell full charge consumption charge amount Qcn input, the consumption charge current Iccn per unit time of each battery cell n is calculated based on (Equation 8). In step S142, each battery The consumption charge current Iccn per unit time of the cell n is stored in the consumption charge current RAM per unit cell time.
Note that the processing in step S14 is performed by the consumption current calculation unit 507 per unit cell time.

FIG. 22 is a workflow diagram showing details of step S15 (calculation of each cell balancer consumption charging current).
In step S151, each cell voltage Vn, current value I, each cell internal resistance Rinn, and the balancer resistance value Rb previously recorded in the microcomputer 401 are input, and the balancer of each battery cell n is calculated based on Equation (9). The consumption charge current Ibn is calculated, and in step S152, the balancer consumption charge current Ibn of each battery cell n is stored in each cell balancer consumption charge current RAM. The process of step S15 is performed by each cell balancer consumption charging current calculation unit 508 of FIG.

FIG. 23 is a workflow diagram showing details of step S16 (each cell balancer drive ratio calculation).
In step S161, balancer drive determination is performed based on each cell voltage Vn and each cell target electrical thickness Vtgn. If each cell voltage Vn is less than each cell target voltage Vtgn, the process proceeds to step S162 to stop the balancer 302, and the cell balancer drive ratio is set to 0 [%]. On the other hand, if each cell voltage Vn is not less than each cell target voltage Vtgn, the process proceeds to step S163 to drive the balancer 302.
In this step S163, each cell balancer drive rate Dutyn is calculated based on (Equation 10) by using each cell unit time consumption charge current Iccn and each cell balancer consumption charge current Ibn as inputs, and in step S164, each cell The upper limit value of the balancer drive ratio Dutyn is determined. When each cell balancer drive ratio Duty is 100 [%] or more, the process proceeds to step S165, and each cell balancer drive ratio Duty = 100 [%]. On the other hand, if each cell balancer drive rate Duty is not 100% or more, the process proceeds to step S166, and each cell balancer drive rate Duty is left as the calculation result in step S163. Note that the processing in step S16 is performed by each cell balancer drive ratio calculation unit 509 in FIG.

Next, the operation described above will be described based on the timing chart of FIG.
FIG. 25A shows the full charge consumption charge amount of the battery cells A and B from the start of charge to the end of charge. FIG. 25B shows the charge current consumption per unit time of the battery cells A and B. Indicates the balancer drive ratio of the battery cells A and B, and FIG. 25D shows the balancer drive state of the battery cells A and B.
Here, the charging rate SOCn and the capacity Cpn in the second embodiment are the same as the values in the first embodiment. In addition, the inter-terminal voltage VA of the battery cell A before charging is 3.8 [V], the inter-terminal voltage VA of the battery cell B is 4.0 [V], and the charging time Tchg is 10 [hr]. Current value I is 4 [A], balancer resistance value Rb is 2 [Ω], internal resistance RinA of battery cell A is 1 [mΩ], and internal resistance RinB of battery cell B is 1 [mΩ] And Further, it is assumed that the vehicle is in a charging operation state, the balancer drive control execution determination is established, and steps S5 to S8 and steps S13 to S16 are executed.

First, the calculation operation of the remaining charge amount and the maximum remaining charge amount of the battery cells A and B at the start of charging will be described.
First, in step S5, the remaining charge amounts QremA and QremB of the battery cells A and B are calculated. From the above conditions, QremA = 40 [Ah] and QremB = 30 [Ah] from (Equation 2).
Next, in step S6, the remaining charge amount maximum value is calculated. Here, the remaining charge amount maximum value Qrem_max = QremA = 40 [Ah].

Next, in step S13, the full charge consumption charge amount of the battery cells A and B is calculated. From the above conditions, the full charge / consumption charge amount QcA of the battery cell A is 0 [Ah] and the full charge / consumption charge amount QcB of the battery cell B is 10 [Ah].
Next, in step S14, the consumed charging current per unit time of the battery cells A and B is calculated. Based on the above conditions, the consumption charge current IccA per unit time of the battery cell A is 0.0 [A] and the full charge consumption charge current IccB of the battery cell B is 1.0 [A] from (Equation 8).

  Next, in step S15, the balancer consumption charging current of the battery cells A and B is calculated. From the above conditions, the balancer consumption charging current IbA of the battery cell A is 1.9 [A] and the balancer consumption charging current IbB of the battery cell B is 2.0 [A] from (Equation 9).

Next, in step S16, the balancer drive ratio of the battery cells A and B is calculated.
First, the voltage VA between the terminals of the battery cell A = the target voltage VtgA of the battery cell A, the voltage VB between the terminals of the battery cell B> the target voltage VtgB of the battery cell A, and the balancer drive ratio DutyA = 0 [% ], The balancer drive ratio of battery cell B DutyB = 50 [%].
Thereafter, charging is performed, and during the charging, the processing from step S5 to step S9 is repeatedly executed, and the full charge consumption charge amount of the battery cells A and B, the consumption charge current per unit time, the balancer consumption charge current, and the balancer drive Go update the rate.
Further, during charging, the remaining charge amount QremA of the battery cell A matches the remaining charge amount maximum value Qrem_max, and the full charge consumption charge amount QcA of the battery cell A is 0 [Ah], the consumed charge current per unit time. IccA is 0 [A], the balancer drive ratio is 0 [%], the balancer 302 of the battery cell A is not driven, and cell balance is not executed.

  On the other hand, the full charge consumption charge amount QcB of the battery cell B is 10 [Ah], and the consumption charge current IccB per unit time is 1.0 [A]. Further, since the balancer consumption charging current IbB of the battery cell B is 2.0 [A], the balancer drive ratio DutyB of the battery cell B is 50 [%], and the balancer 302 of the battery cell B is driven. And cell balancing is executed.

Thereafter, when charging is stopped due to full charge (time t7), the consumption charge current IccB per unit time of the battery cell B becomes 0.0 [A], and the balancer of the battery cell B stops its operation.
In the operation from the start of charging to the end of charging as described above, as shown in FIG. 25, the battery cell A is charged without charging the battery cell A with 40 [Ah], which is the remaining charge amount QremA of the battery cell A. It can be seen that the battery can be fully charged.
That is, the cell balance control of the battery cell A is not executed, and wasteful charging energy consumption can be suppressed and the charging time can be shortened.

  As described above, according to the second embodiment, the remaining charge amount of the battery cells other than the maximum remaining charge amount at the time of full charge can be made the same by driving the balancer of each battery cell intermittently. Thus, the battery cell can be charged efficiently. In addition, since no excessive current flows through the balancer resistor, deterioration and failure due to heat generation of the balancer resistor can be suppressed.

  In addition, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the summary, it can change suitably and can be abbreviate | omitted.

100: Electric vehicle 101: Vehicle control device 102: Motor for driving
103: Inverter, 104: Battery pack,
105: Battery management device, 106: Battery charger,
201: vehicle control device microcomputer, 202: charge control mode determination means,
301: Battery cell 302: Balancer 303: Cell voltage detection means
304: Balancer resistance, 305: Balancer resistance intermittent means,
306: Current detection means 401: Battery management device microcomputer
402: Cell voltage value storage means, 403: Current value storage means,
404: Cell capacity estimation means, 405: Cell balance control execution determination means,
406: cell balance control means, 501: remaining cell charge amount calculation means,
502: remaining charge maximum value calculation means, 503: cell target charge rate calculation means,
504: Cell target voltage calculation means, 505: Balancer drive determination means,
506: full charge consumption charge amount calculation means, 507: consumption charge current calculation means per unit time,
508: Balancer consumption charge current calculation means, 509: Balancer drive ratio calculation means 510: Balancer drive means, 511: Charge time estimation means,
512: Cell internal resistance estimation means

The battery management device according to the present invention includes a cell voltage detection means for detecting a voltage (Vn) between terminals in a plurality of battery cells constituting the battery pack, a current detection means for detecting a charge / discharge current of the battery pack, Cell remaining charge amount calculating means for calculating a remaining charge amount (Qremn) of each battery cell based on a charge state of the battery pack, and a remaining value for calculating a maximum value (Qrem_max) from the remaining charge amount (Qremn) of each battery cell A charge amount maximum value calculating means, a cell target charge rate calculating means for calculating a target charge rate (SOC_tgn) at which the remaining charge amount of each battery cell becomes a maximum value (Qrem_max), and each of the cell target charge rate calculating means wherein the target charging rate of the battery cell (SOC_tgn) target of each battery cell Pressure and the cell target voltage calculating means for calculating the (Vtgn), the balancer according to the difference of the cell voltage detecting unit terminal voltage due to (Vn) and said by cell target voltage calculation unit target voltage of each battery cell (Vtgn) Balancer drive determination means for determining whether or not to perform drive, and configured to execute individual cell balance control for each of the battery cells based on the determination result of the balancer drive determination means. It is what.

前記セル目標充電率算出手段による各バッテリーセルの目標充電率（ＳＯＣ＿ｔｇｎ）から前記各バッテリーセルの目標電圧（Ｖｔｇｎ）を算出するセル目標電圧算出手段と、前記セル電圧検出手段による端子間電圧（Ｖｎ）および前記セル目標電圧算出手段による前記各バッテリーセルの目標電圧（Ｖｔｇｎ）の差分に応じてバランサ駆動を行うか否かを判定するバランサ駆動判定手段とを備え、前記バランサ駆動判定手段の判定結果に基づいて前記各バッテリーセルのそれぞれに個別のセルバランス制御を実行するように構成したことを特徴とするものである。 The battery management device according to the present invention includes a cell voltage detection means for detecting a voltage (Vn) between terminals in a plurality of battery cells constituting the battery pack, a current detection means for detecting a charge / discharge current of the battery pack, Cell remaining charge amount calculating means for calculating a remaining charge amount (Qremn) of each battery cell based on a charge state of the battery pack, and a remaining value for calculating a maximum value (Qrem_max) from the remaining charge amount (Qremn) of each battery cell Charge amount maximum value calculating means, cell target charge rate calculating means for calculating a target charge rate (SOC_tgn) at which the remaining charge amount of each battery cell becomes a maximum value (Qrem_max) by the following equation ;

Cell target voltage calculation means for calculating the target voltage (Vtgn) of each battery cell from the target charge rate (SOC_tgn) of each battery cell by the cell target charge rate calculation means, and terminal voltage (Vn) by the cell voltage detection means ) And balancer drive determination means for determining whether or not to perform balancer drive according to the difference between the target voltages (Vtgn) of the respective battery cells by the cell target voltage calculation means, and the determination result of the balancer drive determination means Based on the above, it is configured to execute individual cell balance control for each of the battery cells.

Claims (5)

A cell voltage detecting means for detecting a voltage (Vn) between terminals in a plurality of battery cells constituting the battery pack;
Current detecting means for detecting a charge / discharge current of the battery pack;
Cell remaining charge amount calculating means for calculating a remaining charge amount (Qremn) of each battery cell based on a charge state of the battery pack;
A remaining charge amount maximum value calculating means for calculating a maximum value (Qrem_max) from the remaining charge amount (Qremn) of each battery cell;
A cell target charge rate calculating means for calculating a target charge rate (SOC_tgn) at which the remaining charge amount of each battery cell becomes a maximum value (Qrem_max);
Cell target voltage calculation means for calculating a target voltage (Vtgn) from a target charge rate (SOC_tgn) of each battery cell by the cell target charge rate calculation means;
Balancer drive determination means for determining whether or not to perform balancer drive according to the difference between the terminal voltage (Vn) by the cell voltage detection means and the target voltage (Vtgn) by the cell target voltage calculation means;
A battery management device configured to execute individual cell balance control for each of the battery cells based on a determination result of the balancer drive determination means. Consumption charge current calculation means for calculating consumption charge current (Iccn) to be consumed per unit time of each battery cell;
A balancer consumption charge current calculation means for calculating a balancer consumption charge current (Ibn) that can be consumed per unit time by the balancer of each battery cell;
A balancer driving ratio (Dutyn) per unit time of each battery cell in accordance with a ratio of the consumption charging current (Iccn) by the consumption charging current calculation means and the balancer consumption charging current (Ibn) by the balancer consumption charging current calculation means And a balancer drive ratio calculating means for calculating
The battery management device according to claim 1, wherein cell balance control is executed based on a balancer drive ratio (Dutyn) by the balancer drive ratio calculation means.   When the inter-terminal voltage (Vn) in the battery cell becomes smaller than the target voltage (Vtgn) by the cell target voltage calculation means, the balancer drive ratio (Dutyn) of the balancer drive ratio calculation means is set to zero. The battery management device according to claim 2.   The battery management apparatus according to any one of claims 1 to 3, wherein the battery pack is for driving a vehicle mounted on a vehicle.   The vehicle is provided with charge control mode determination means for determining a charge control mode of the battery cell, and performs cell balance control when the charge control mode determination means determines that the vehicle is in a charging operation. The battery management apparatus according to claim 4, wherein the battery management apparatus is configured to do so.

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