JP5476020B2 - Charging control system, battery pack, vehicle, and charging control method - Google Patents

Description

  The present invention relates to a charge control system, a battery pack, a vehicle, and a charge control method.

  Patent Document 1 describes an electric vehicle equipped with a plurality of batteries for driving a motor.

Japanese Patent Laid-Open No. 06-046508

  However, in the prior art, since the characteristics of the plurality of batteries are different from each other, the remaining charge amounts of the plurality of batteries vary. In particular, the vehicle is subject to various environments such as the temperature situation of the area where the vehicle travels, the temperature situation that varies depending on the arrangement position in the vehicle, and the impact, etc. The battery's remaining charge tends to vary. When the remaining charge amounts of the plurality of batteries vary, the internal resistance values of the plurality of batteries increase, so that the electric energy stored in the plurality of batteries cannot be efficiently used.

  In order to solve the above problem, in the first aspect of the present invention, a charge control system, a charge remaining amount acquisition unit that acquires values indicating the remaining charge amounts of a plurality of batteries connected in series, A charging battery selection unit that selects, as a charging target battery, a battery that has a lower remaining charge than other batteries among a plurality of batteries, and a selection charging circuit that selectively charges the charging target battery.

  The charge control system may further include a discharge battery selection unit that selects, as a discharge target battery, a battery that has a higher remaining charge than other batteries among the plurality of batteries. The battery to be charged may be selectively charged using the electric energy that is provided.

  In the charge control system, the remaining charge acquisition unit may measure the internal resistance value of each of the plurality of batteries as a value indicating the remaining charge of each of the plurality of batteries. Among these batteries, a battery having a larger internal resistance value than other batteries may be selected as the battery to be charged.

  In the charge control system, the discharge battery selection unit may select a battery having a smaller internal resistance value than the other batteries among the plurality of batteries as a discharge target battery.

  In the charging control system, the selective charging circuit selectively selects a battery to be charged using electrical energy stored in at least one battery included in a second battery group different from the first battery group including a plurality of batteries. May be charged.

  The charge control system may further include a discharge battery selection unit that selects, as a discharge target battery, a battery having a higher remaining charge than other batteries among the second battery group including a plurality of batteries connected in series. The selective charging circuit may selectively charge the battery to be charged using electrical energy stored in the battery to be discharged.

  In the above charge control system, the remaining charge acquisition unit is a value indicating the remaining charge of each of the plurality of batteries included in the first battery group, and the internal resistance value of each of the plurality of batteries included in the first battery group. The charging battery selecting unit may select a battery having a larger internal resistance value than the other batteries among the plurality of batteries included in the first battery group as the charging target battery.

  In the above charge control system, the remaining charge acquisition unit is a value indicating the remaining charge of each of the plurality of batteries included in the first battery group, and the internal resistance value of each of the plurality of batteries included in the first battery group. The discharge battery selection unit may select a battery having a smaller internal resistance value than the other batteries among the plurality of batteries included in the second battery group as the discharge target battery.

  In the charge control system, the plurality of batteries may be lithium ion batteries.

  In the 2nd aspect of this invention, it is a battery pack, Comprising: A some battery and the said charge control system are provided.

  In a third aspect of the present invention, the vehicle includes the battery pack and a motor that is driven by electric energy stored in the battery pack.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 shows an exemplary configuration of an electric vehicle 100. Another example of the configuration of the electric vehicle 100 is shown. Another example of the configuration of the electric vehicle 100 is shown. Another example of the configuration of the electric vehicle 100 will be described. An example of the characteristics of the battery 120 is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 shows an example of the configuration of the electric vehicle 100. Hereinafter, an example of the configuration of the electric vehicle 100 as an example of the vehicle will be described.

  The electric vehicle 100 includes a battery pack 110, an inverter 112, and a motor 114. Battery pack 110 includes a first battery group in which a plurality of batteries 120 are connected in series. The battery 120 may be a cell or a battery module. The inverter 112 converts the electric energy supplied from the battery pack 110 from direct current to alternating current. The inverter 112 supplies the converted electric energy to the motor 114. The motor 114 drives the wheels of the electric vehicle 100.

  Battery pack 110 further includes a charge control system 130. The charging control system 130 is realized by an electronic circuit such as an IC. The charge control system 130 includes a remaining charge acquisition unit 132, a rechargeable battery selection unit 134, a discharge battery selection unit 136, and a selective charging circuit 138.

  The remaining charge acquisition unit 132 acquires a value indicating the remaining charge of each of the plurality of batteries 120 connected in series. For example, the remaining charge acquisition unit 132 may acquire the internal resistance value of each of the plurality of batteries 120 as a value indicating the remaining charge of each of the plurality of batteries 120. The remaining charge acquisition unit 132 may acquire an internal resistance value when each of the plurality of batteries 120 outputs electrical energy of a predetermined current. The remaining charge acquisition unit 132 may acquire the internal resistance value by detecting the voltage and current of the battery 120 and calculating the internal resistance value based on the detected voltage and current. The remaining charge acquisition unit 132 may acquire the voltage of each of the plurality of batteries 120 as a value indicating the remaining charge of each of the plurality of batteries 120.

  The remaining charge acquisition unit 132 detects the current of each of the plurality of batteries 120 when the motor 114 is not driving a wheel or when the load of the motor 114 is driven with a constant amount of power. Also good. Since the rotation speed of the motor 114 changes with time, the amount of power supplied from the battery pack 110 to the motor 114 also changes accordingly. Therefore, even when the current of the battery 120 is detected when the rotation speed of the motor 114 changes with time, an accurate current cannot be detected. The remaining charge acquisition unit 132 may detect a current by connecting a constant load such as a resistor to the battery 120.

  The charging battery selection unit 134 selects a charging target battery among the plurality of batteries 120. Specifically, the rechargeable battery selection unit 134 includes a battery 120 having a smaller remaining charge than the other batteries 120 among the plurality of batteries 120 based on the value indicating the remaining charge acquired by the remaining charge acquisition unit 132. Is selected as the battery to be charged. For example, when the remaining amount of charge is smaller as the internal resistance value is larger, the rechargeable battery selection unit 134 selects a battery 120 having a larger internal resistance value than the other batteries 120 among the plurality of batteries 120 as a battery to be charged. May be.

  The discharge battery selection unit 136 selects a discharge target battery. Specifically, the discharge battery selection unit 136 includes a battery 120 having a higher remaining charge than the other batteries 120 among the plurality of batteries 120 based on the value indicating the remaining charge acquired by the remaining charge acquisition unit 132. Is selected as the battery to be discharged. For example, when the remaining amount of charge is smaller as the internal resistance value is larger, the discharge battery selection unit 136 selects a battery 120 having a smaller internal resistance value than the other batteries 120 among the plurality of batteries 120 as a discharge target battery. May be.

  The selective charging circuit 138 selectively charges the charging target battery selected by the charging battery selection unit 134. The selective charging circuit 138 may selectively charge the charging target battery selected by the charging battery selecting unit 134 using the electrical energy stored in the discharging target battery selected by the discharge battery selecting unit 136. The selective charging circuit 138 may charge another battery 120 using electrical energy stored in one battery 120 in order to reduce the sum of the internal resistance values of the plurality of batteries 120. The selective charging circuit 138 uses the electric energy stored in the plurality of batteries 120 including the one battery 120 to make the plurality of batteries including the other batteries, in order to make the remaining charge amount of the plurality of batteries 120 uniform. You may charge.

  The selective charging circuit 138 may selectively charge the battery to be charged according to the remaining charge of the battery 120 having the largest remaining charge among the plurality of batteries 120. The charge control system 130 sequentially selects the batteries 120 with the smallest remaining charge as the discharge target batteries, and selectively charges the selected charge target batteries, thereby reducing the difference in the remaining charge amounts of the plurality of batteries 120. May be.

  2 and 3 show another example of the configuration of the electric vehicle 100. FIG. The electric vehicle 100 shown in FIG. 2 further includes a second battery group in which a plurality of batteries 120 are connected in series, and the first battery group and the second battery group are connected in parallel. The configuration differs from the electric vehicle 100 shown in FIG. On the other hand, the electric vehicle 100 shown in FIG. 3 does not include the discharge battery selection unit 136, and the charge control system 130 further includes a spare battery 300 as another example of the second battery group, as shown in FIG. The configuration is different from that of the electric vehicle 100.

  The selective charging circuit 138 uses the electrical energy stored in at least one battery included in a second battery group different from the first battery group including the plurality of batteries 120 to be charged by the charging battery selection unit 134. The battery may be selectively charged.

  For example, in the electric vehicle 100 shown in FIG. 2, the selective charging circuit 138 uses the electric energy stored in the battery 120 included in the second battery group, and the charging target selected by the charging battery selection unit 134. The battery may be selectively charged. Furthermore, the discharge battery selection unit 136 may select a battery having a higher remaining charge than the other batteries 120 among the plurality of batteries 120 included in the second battery group as a discharge target battery. In this case, the selective charging circuit 138 uses the electrical energy stored in the discharge target batteries included in the second battery group selected by the discharge battery selection unit 136 to select the charge target battery selected by the charge battery selection unit 134. You may charge selectively.

  In the electric vehicle 100 shown in FIG. 2, the remaining charge acquisition unit 132 uses the plurality of batteries 120 included in the first battery group as values indicating the remaining charge amounts of the plurality of batteries 120 included in the first battery group. Each of the internal resistance values may be measured. In this case, the rechargeable battery selection unit 134 may select a battery having a larger internal resistance value than the other batteries 120 among the plurality of batteries 120 included in the first battery group as a charge target battery. Furthermore, the discharge battery selection unit 136 may select a battery having a smaller internal resistance value than the other batteries 120 among the plurality of batteries 120 included in the second battery group as a discharge target battery.

  On the other hand, in the electric vehicle 100 shown in FIG. 3, the selective charging circuit 138 selectively charges the charging target battery selected by the charging battery selection unit 134 using the electrical energy stored in the spare battery 300. Also good. The spare battery 300 may be a battery dedicated to charging the battery 120, or may be a battery for another electrical system. For example, the spare battery 300 may be an auxiliary battery provided in the vehicle of the electric vehicle 100 for an electric system such as a light, a power window, and an electric seat.

  FIG. 4 shows still another example of the configuration of the electric vehicle 100. The electric vehicle 100 shown in FIG. 4 is different from the electric vehicle 100 shown in FIG. 1 in that the charging control system 130 further includes an energy conversion unit 400 without including the discharge battery selection unit 136.

  The energy conversion unit 400 converts mechanical energy or natural energy into electrical energy. Specifically, the energy conversion unit 400 includes a solar generator 402 and a dynamo generator 404. The solar generator 402 converts solar energy as an example of natural energy into electric energy. The dynamo generator 404 converts rotational energy, which is an example of mechanical energy, into electrical energy. For example, the dynamo generator 404 converts the rotational kinetic energy of the motor 114 into electrical energy. The energy conversion unit 400 is a machine that uses a device other than the solar generator 402 and the dynamo generator 404, such as a piezoelectric element that converts mechanical energy such as vibration and impact into electric energy, and a wind power generator that converts wind power into electric energy. Energy or natural energy may be converted to electrical energy.

  In the electric vehicle 100 shown in FIG. 4, the selective charging circuit 138 may selectively charge the charging target battery selected by the charging battery selecting unit 134 using the electric energy converted by the energy converting unit 400. .

  FIG. 5 shows an example of the characteristics of the battery 120. FIG. 5 is a graph showing the relationship between the remaining charge of the battery 120 and the internal resistance value, in which the vertical axis indicates the internal resistance value and the horizontal axis indicates the remaining charge amount. As the graph of FIG. 5 shows, the smaller the remaining charge of the battery 120, the greater the degree of increase in the internal resistance of the battery 120. For this reason, the sum of the internal resistance values of the plurality of batteries 120 can be further reduced by charging the battery 120 having a small remaining charge and increasing the remaining charge of the battery 120. In addition, even when the remaining charge of the battery 120 is further increased by charging the battery 120 with a small remaining charge using the electrical energy stored in the battery 120 with a large remaining charge, the plurality of batteries 120 The sum of the internal resistance values can be made smaller.

  The charging control system 130 may selectively charge the charging target battery at various timings. For example, the charging control system 130 may selectively charge the charging target battery periodically in a predetermined cycle. In addition, the charging control system 130 periodically determines whether or not a predetermined condition is met in a predetermined cycle, and if it is determined that the condition is met, the charging control system 130 selectively selects a battery to be charged. May be charged. For example, the charging control system 130 may selectively charge the charging target battery when the difference between the remaining charge amounts of the plurality of batteries 120 becomes a predetermined amount or more. In addition, the charging control system 130 periodically simulates a reduction amount or sum of internal resistance values by selectively charging a battery to be charged, and determines that the reduction amount exceeds a predetermined amount, or the sum is The battery to be charged may be selectively charged when it is determined that the amount is equal to or less than the predetermined amount. In addition, the charging control system 130 may selectively charge the charging target battery at a timing when the electric vehicle 100 performs a predetermined operation. For example, the charging target battery may be selectively charged at a timing such as when charging of the electric vehicle 100 is started, when charging is completed, when the vehicle is stopped, or when the vehicle is parked.

  As described above, according to the charge control system 130 of the present embodiment, by selectively charging the charging target battery having a lower remaining charge than the other batteries 120 among the plurality of batteries 120, The difference in remaining charge can be made smaller. Thereby, since the sum of the internal resistance values of the plurality of batteries 120 becomes smaller, the electric energy stored in the plurality of batteries 120 can be used efficiently.

  In addition, according to the charge control system 130 of the present embodiment, the battery to be charged is selectively selected using electrical energy stored in the battery 120 having a lower remaining charge than the other batteries 120 among the plurality of batteries 120. Thus, the difference in the remaining charge amounts of the plurality of batteries 120 can be further reduced with a simple system configuration without using external electric energy.

  Moreover, according to the charging control system 130 of the present embodiment, the charging target battery included in the first battery group is selectively used by using the electrical energy stored in the second battery group different from the first battery group. By charging, a plurality of batteries included in the first battery group without using external electric energy and without reducing the electric energy stored in the first battery group used to drive the motor 114 The difference in the remaining charge of the battery 120 can be further reduced.

  Further, according to the charge control system 130 of the present embodiment, mechanical energy or natural energy is converted into electric energy, and the electric energy generated thereby is selectively charged, thereby selectively charging the battery to be charged. The difference in the remaining charge amounts of the plurality of batteries 120 can be made smaller without using external electric energy and without reducing the electric energy stored in the plurality of batteries 120 used for driving the motor 114.

  Note that the plurality of batteries 120 described in the present embodiment may be lithium ion batteries that are less likely to spontaneously discharge and are likely to have a difference in the remaining charge amounts of the plurality of batteries. Even in this case, the difference in the remaining charge amounts of the plurality of lithium ion batteries can be further reduced by the charge control system 130 of the present embodiment. In the present embodiment, an example in which the charging control system 130 is provided in the electric vehicle 100 has been described. However, the charging control system 130 may be provided in another device or device including a plurality of batteries.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Electric vehicle, 110 Battery pack, 112 Inverter, 114 Motor, 120 battery, 130 Charge control system, 132 Charge remaining amount acquisition part, 134 Charge battery selection part, 136 Discharge battery selection part, 138 Selection charge circuit, 300 Reserve battery, 400 Energy conversion unit, 402 Solar generator, 404 Dynamo generator

Claims (7)

The remaining charge amounts of the plurality of batteries connected in series included in the first battery group and the plurality of batteries connected in series included in the second battery group connected in parallel to the first battery group are shown. A remaining charge acquisition unit for acquiring a value;
A charging battery selection unit that selects a battery having a lower remaining charge than other batteries among the plurality of batteries included in the first battery group as a charging target battery;
A discharge battery selection unit that selects, as a discharge target battery, a battery having a larger remaining charge than other batteries among the plurality of batteries included in the second battery group;
When it is determined that the amount of decrease in the internal resistance value by selectively charging the battery to be charged is equal to or greater than a predetermined amount, or the internal resistance values of the plurality of batteries included in the first battery group A charge control system comprising: a selective charging circuit that selectively charges the battery to be charged using electrical energy stored in the battery to be discharged when it is determined that the sum is equal to or less than a predetermined amount . The remaining charge acquiring unit, as each value indicating the remaining charge of said plurality of cells included in the first cell group, each of the internal resistance of the plurality of cells included in the first cell group Measure the value,
2. The charge control system according to claim 1, wherein the charging battery selection unit selects a battery having a larger internal resistance value than the other batteries among the plurality of batteries included in the first battery group as the charging target battery. . 3. The charge control system according to claim 2 , wherein the discharge battery selection unit selects, as the discharge target battery, a battery having a smaller internal resistance value than other batteries among the plurality of batteries included in the second battery group. . The charge control system according to any one of claims 1 to 3 , wherein the plurality of batteries are lithium ion batteries. The plurality of batteries;
A battery pack provided with the charge control system according to any one of claims 1 to 4 . The battery pack according to claim 5 ;
A vehicle comprising: a motor driven by electric energy stored in the battery pack. The remaining charge amounts of the plurality of batteries connected in series included in the first battery group and the plurality of batteries connected in series included in the second battery group connected in parallel to the first battery group are shown. A remaining charge acquisition step for acquiring a value;
A charging battery selection step of selecting, as a charging target battery, a battery having a lower remaining charge than other batteries among the plurality of batteries included in the first battery group;
A discharge battery selection step of selecting, as a discharge target battery, a battery having a larger remaining charge than other batteries among the plurality of batteries included in the second battery group;
When it is determined that the amount of decrease in the internal resistance value by selectively charging the battery to be charged is equal to or greater than a predetermined amount, or the internal resistance values of the plurality of batteries included in the first battery group A charge control method comprising: a selective charging step of selectively charging the battery to be charged using electrical energy stored in the battery to be discharged when it is determined that the sum is equal to or less than a predetermined amount .

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