JP2004301848A - Battery evaluation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evaluate true performance of a battery pack comprising a plurality of batteries connected in series. <P>SOLUTION: This device has variable electric current sources 11 and electronic loads 12 provided in a main electric current path connected in series with the plurality of chargeable batteries 10, and connected in parallel each other, a main current sensor 13 for detecting an electric current value flowing in the main electric current path, electronic loads 17 connected respectively in parallel to the respective batteries 10, a load current sensor 18 for detecting an electric current value flowing in each of the electronic loads 12, a CPU 14 for variable-controlling the variable electric current sources 11 and the electronic loads 12, 17 according to a battery evaluation program to evaluate the performance, based on the respective current values detected by the main current sensor 13 and the load current sensor 18, and a data output part 24 for outputting an evaluated result by the CPU 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a battery evaluation device for evaluating the performance of an assembled battery including a plurality of batteries connected in series.

  At present, rechargeable batteries (secondary batteries) such as lithium ion batteries and nickel cadmium batteries are known. This secondary battery is charged by, for example, a battery charger as shown in FIG.

  That is, in the battery charging device shown in FIG. 11, the positive electrode of the DC current source 50 is connected to the positive electrode 51 for charging via the switch 53, and the negative electrode of the DC current source 50 is connected to the negative electrode 52 for charging. ing. The positive charging electrode 51 and the negative charging electrode 52 are connected in series, and between them, for example, three secondary batteries 54 are connected in series. Further, a discharge circuit in which a resistor 55 and a switch 56 are connected in series is provided in parallel with each of the secondary batteries 54.

  In such a battery charger, the secondary battery 54 is provided, and when the switch 53 is turned on, charging of the secondary battery 54 is started. At the start of charging, the switches 56 of the respective discharge circuits are turned off.

  Here, when the secondary batteries 54 are connected in series and charged in parallel in this manner, the secondary batteries 54 have variations in their capacities, so that the charging state varies.

  For this reason, conventionally, the voltages of the three secondary batteries 54 are respectively detected, and when the charging state varies, the secondary battery 54 that has been charged the most and the secondary battery has been charged the second. The switch 56 of the discharge circuit of the secondary battery 54 was turned on. As a result, the electric power charged in the secondary battery 54 that has been charged the most and the secondary battery 54 that has been charged the second is discharged through the discharge circuit.

  Next, the discharge of the secondary battery 54, which is the most advanced, and the secondary battery 54, which is the second most advanced, are advanced, and the voltage values of these secondary batteries 54 are the most delayed. When the voltage value becomes the same as the voltage value of the secondary battery 54, the switch 56 of the discharge circuit that has been turned on is turned off. Thereby, charging is restarted again.

  In the conventional battery charger, charging / discharging is repeated by turning on / off the switch 56 as described above, and the plurality of secondary batteries 54 are charged evenly.

  However, if charging is performed while repeating charging and discharging as described above, all the secondary batteries are charged according to the state of charge of the secondary battery that has been delayed the most, and multiple secondary batteries are all charged. There is a problem that it takes time to fully charge.

  In addition, there is always the problem of overcharging when charging a battery. This overcharging places a burden on each circuit of the battery and the charging device, and adversely affects safety aspects such as heat generation and damage. Therefore, development of a battery charger capable of preventing overcharge and performing safe charging is desired.

  Furthermore, the performance evaluation of a battery is usually performed by repeating charging, rest, discharge, and rest as one cycle, and repeating this for a plurality of cycles. However, in an actual actual use state, charge, discharge, and rest occur irregularly. Therefore, it is not enough quality evaluation. Also, in a battery pack composed of a plurality of batteries connected in series, charging must be terminated when the battery with the smallest capacity is fully charged, and an evaluation can be performed in consideration of the variation in capacity of each battery. However, there was a problem that the true performance as an assembled battery could not be evaluated.

  In view of the above-mentioned conventional problems, an object of the present invention is to provide a battery evaluation device capable of evaluating the true performance of an assembled battery including a plurality of batteries connected in series.

  A battery evaluation device according to the present invention is provided with a variable current source and a variable load unit provided in a main current path in which a plurality of rechargeable batteries are connected in series and connected in parallel with each other, and detects a current value flowing in the main current path. A main current sensor, a variable load means connected in parallel to each battery, a load current sensor for detecting a current value flowing through each variable load means, and a variable current source and variable load means according to a battery evaluation program. An evaluation unit for performing control and performing performance evaluation based on each current value detected by the main current sensor and the load current sensor, and an output unit for outputting an evaluation result by the evaluation unit.

  Further, the battery evaluation device according to the present invention includes a temperature sensor for measuring the temperature of each battery, and evaluates a temperature characteristic by the evaluation means based on a detection output from the temperature sensor.

  In addition, the battery evaluation device according to the present invention includes an evaluation condition setting input unit, and the evaluation unit is configured to control the variable current source and each of the variable current sources according to a battery evaluation program corresponding to the evaluation condition set by the setting input unit. The variable control of the load means is performed, and the performance is evaluated based on each current value detected by the main current sensor and the load current sensor.

  In the present invention, each battery can be fully charged, and the difference in the capacity of each battery, the true capacity as an assembled battery, the true cycle characteristics as an assembled battery, that is, the change in capacity due to repeated charging and discharging, etc. can be safely and accurately determined. Can be evaluated. In addition, it is possible to simulate the actual use state, and it is possible to analyze market defects, avoid troubles in advance, or perform thorough quality control before shipping.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The battery evaluation device 100 according to the present invention evaluates an assembled battery composed of a plurality of batteries connected in series, for example, an assembled battery composed of three batteries 10 connected in series as shown in FIG. A current source 11 and an electronic load 12 provided in a main current path in which three rechargeable batteries 10 are connected in series and connected in parallel with each other. The main current path is provided with a main current sensor 13 for detecting a current flowing through the main current path.

  The current source 11 is a variable current source that supplies a charging current to the battery pack including the three batteries 10, and its output current value is variably controlled by a controller 14. The current source 11 supplies a charging current to the battery pack via a diode 15 for preventing backflow. The electronic load 12 is a variable load unit through which a discharge current of the battery pack including the three batteries 10 flows, and is, for example, a variable load resistor using an FET. It is variably controlled. Further, the main-in current sensor 15 detects a current flowing in the main current path, and supplies the current value to the controller 14 via an A / D converter 16.

  The battery evaluation device 100 includes an electronic load 17 and a load current sensor 18 connected in series to each other of the batteries 10 of the battery pack. Each of the electronic loads 17 is a variable load means for individually varying a charging current flowing through each of the batteries 10, and is composed of, for example, a variable load resistor using an FET. It is variably controlled by a control signal supplied via the converter 19. Each of the load current sensors 18 detects a current flowing through each of the electronic loads 17 and supplies each current value to the controller 14 via the A / D converter 16. .

  Further, the battery evaluation device 100 includes each temperature sensor 20 attached to each battery 10 of the assembled battery. Each of the temperature sensors 20 detects the temperature of each of the batteries 10 and supplies each detected output to the controller 14 via the A / D converter 16.

  Further, the battery evaluation device 100 includes a display unit 21 connected to the controller 14, a data input unit 22 such as a keyboard and a mouse, a data storage unit 23 such as a hard disk and a magneto-optical recording device, and a data output unit 24 such as a printer. Is provided.

  In the battery evaluation device 100, the controller 14 is configured to control the current source 11 and each of the current sources 11 and Evaluation means for performing variable control of the electronic loads 12 and 17 and for evaluating the performance of the battery pack composed of the batteries 10 based on the detection outputs of the men-in current sensors 15, the load current sensors 18 and the temperature sensors 20. Consisting of a microcomputer that functions as

  The controller 14 controls each of the electronic loads 12 based on the value of each load current detected by each load current sensor 18 so as to maintain the charging voltage value of each battery 10 at a specified value. The current source 11 is controlled so that an excessive current does not flow through each electronic load 17 and each load current sensor 18. Further, the controller 14 controls the current source 11 based on the current value detected by the main current sensor 13 so as to maintain the value of the current flowing in the main current path at a specified value or less.

  This allows each battery 10 to be fully charged safely without being overcharged even when there is a difference in the capacity of each battery 10.

  Then, the controller 14 outputs the evaluation result executed according to the battery evaluation program through the display unit 21 or the data output unit 24. Data indicating the evaluation result is stored in the data storage unit 23.

  The test pattern setting operation is performed using the data input unit 22 and the display unit 21.

  Here, the controller 14 including the microcomputer has, for example, the following software function for battery evaluation.

1. Power-on initial check function After the power of the apparatus is turned on, the following contents are checked. If an abnormality occurs, the contents are displayed on the display unit 21 and stored in the data storage unit 23.
(1) Communication function (2) Detected current value of main current sensor 13 and load current sensor 17 (3) Detected value of temperature sensor 20 (4) Abnormal output of module controller such as electronic load 17 (5) Abnormality of current source 11 (6) Abnormality of electronic load 12

2. Charge / discharge condition setting function The charge / discharge pattern and the number of execution cycles of the pattern are set in a maximum of 99 combinations of five types of operation modes (charge 1, charge 2, discharge, pause, DCR). In each operation mode, the following parameters are set.

(Charging 1)
(1) Data storage / not storage (2) Data sampling time 1 second unit to 10 minute unit (3) Charge current value 0.00 to 400.00 [A] Current value of current source 11 (4) Charge voltage value 0 000 to 5.000 [V] Charge voltage value of each battery 10 (5) Load current value 0.00 to 10.00 [A] Maximum current value of each load current (6) Charge termination condition Select the following contents (Multiple selections are allowed)
・ Current 0.00 to 400.00 [A]
Ends when the current reading of all batteries is below the set value. Voltage 0.000 to 5.000 [V]
End when the voltage reading of any battery is equal to or higher than the set value. Charging time 00H00M00S to 12H00M00S End at the set time from the start of charging. (7) Monitoring items (monitor readings from module controller)
・ Maximum current 0.00 to 410.00 [A]
・ Upper limit voltage 0.000 to 5.100 [V]
・ Maximum temperature 0.00-100.0 [° C]

(Charging 2)
(1) Data storage / not storage (2) Data sampling time 1 second unit to 10 minute unit (3) Charge current value 0.00 to 400.00 [A] Current value of current source 11 (4) Charge voltage value 0 000 to 35,000 [V] Charge voltage value of assembled battery (5) Charge termination condition Select the following contents (multiple selections are possible)
・ Current 0.00 to 400.00 [A]
Ends when the current reading of all batteries is below the set value. Voltage 0.000 to 5.000 [V]
End when the voltage reading of any of the batteries is equal to or higher than the set value. Charging time 00H00M00S to 12H00M00S End at the set time from the start of charging.
・ Maximum current 0.00 to 410.00 [A]
・ Upper limit current 0.000 to 5.100 [V]
・ Maximum temperature 0.00-100.0 [° C]

(Discharge)
(1) Save / Not save data (2) Data sample time 1 second unit to 10 minute unit (3) Selection of load operation mode and value setting (select one of the following)
・ Constant current 0.00 to 400.00 [A]
・ Constant power 0-14000 [W]
(4) Discharge termination condition Select the following contents (multiple selections are allowed)
・ Voltage 0.000-5.000 [V]
Ends when one or more voltage readings of each battery are equal to or higher than the set value. Charging time 00H00M00S to 12H00M00S Ends at the set time from the start of discharging. (5) Monitoring item (Monitors reading from module controller)
・ Maximum current 0.00 to 410.00 [A]
・ Lower limit current 0.000-5.000 [V]
・ Maximum temperature 0.00-100.0 [° C]

(Pause)
(1) Data save / no (2) Data sample time 1 second unit to 10 minute unit (3) Rest time 00H00M00S to 12H00M00S Set the time to cut off the charge / discharge current

(DCR)
(1) Data saving / not saving (2) Data sampling time 1 second unit to 10 minute unit (3) Constant current 1 (I1) 0.00 to 400.00 [A]
(4) Constant current 2 (I2) 0.00 to 400.00 [A]
(5) Discharge time 1 (T1) 00S to 59S End at set time from start of discharge (6) Discharge time 2 (T2) 00S to 59S End at set time from start of discharge (7) Monitor item (reading value from module controller Monitoring)
・ Maximum current 0.00 to 410.00 [A]
・ Lower limit current 0.000-5.000 [V]
・ Maximum temperature 0.00-100.0 [° C]

3. Execution start / stop function of charge / discharge test Starts or stops the charge / discharge test. At the start, the following battery parameters are set.
(1) Battery name (10 characters)
(2) Battery pack number (10 characters)
(3) Battery numbers 1 to 7 (7 characters each)
(4) Volume 0.000 to 99.999 [l]
(5) Weight 0.000 to 99.999 [Kg]
(6) Ambient temperature 0.00 to 100.0 [° C]

4. Voltage / current / temperature display / printing function The voltage, current, and temperature of each battery are read from the module controller and displayed on the display unit 21 or printed on the data output unit 24. Reading is performed every three seconds regardless of whether the charge / discharge test is being executed or stopped, and the latest data is displayed. The display / print method is data (numerical value) or histogram.

5. Display / Print Function of Measurement Results The following contents are calculated for each step from the measurement data file, and are displayed on the display unit 21 or printed by the data output unit 24.

(Charging 1)
(1) Battery charging capacity (AH, WH)
(2) Maximum / minimum temperature value (for each temperature sensor 20)
(3) Start / end voltage at both ends of each battery and battery pack

(Charging 2)
(1) Battery charging capacity (AH, WH)
AH: integrated value of current value [A] / charge time [H]
WH: integral value of voltage value [V] / charge time [H]
(2) Maximum / minimum temperature value (for each temperature sensor 20)
(3) Start / end voltage at both ends of each battery and battery pack

(Discharge)
(1) Discharge capacity of each battery (AH, WH)
AH: integrated value of current value [A] / discharge time [H]
WH: integral value of voltage value [V] / discharge time [H]
(2) Maximum / minimum temperature value (for each temperature sensor 20)
(3) Start / end voltage at both ends of each battery and battery pack

(Pause)
(1) Maximum / minimum temperature value (for each temperature sensor 20)
(2) Start / end voltage at both ends of each battery and battery pack

(DCR)
(1) DCR value (DC resistance value [Ω]) of each battery and assembled battery
The DCR value is obtained by discharging I1 [A] for T1 [seconds], subsequently discharging I2 [A] for T2 [seconds], and calculating the voltage between both ends of the battery alone or the assembled battery when flowing I1 and I2. , V2,
DCR = | (V1-V2) / (I1-I2) |
Is calculated.
(2) Voltage at both ends of each battery and battery pack when I1 and I2 flow

Other (common)
(1) Battery parameters (2) Start / end time and time in between (for each step)
(3) Charge / discharge conditions other than monitoring items (for each step)

6. Display / Print Function of Measurement Data The following contents are displayed on the display unit 21 or printed by the data output unit 24 from the measurement data file.
(1) Sample data and sample time of each battery voltage, current, and temperature (2) Battery parameters (3) Start / end time and time between (each step)
(4) Charge / discharge conditions (for each step)

7. Display / Print Function of Charge / Discharge Curve The following contents are displayed on the display unit 21 or printed on the data output unit 24 from the measurement data file.
(1) Charge / discharge curve (voltage, current, temperature)
(2) Battery parameters (3) Display battery specification and selection (4) Display time axis setting (5) Test start date and time

8. Abnormal history display / printing function Abnormal contents / history (date and time) accumulated in the data storage unit 23 are displayed on the display unit 21 or printed on the data output unit 24.

9. Function to set measurement data saving method Sets the following contents for saving measurement data.
(1) Save / Not save data When “No” is selected, “Save” set in charge / discharge conditions is ignored.
(2) File name to save data

10. Printing function of charge / discharge condition The charge / discharge condition is printed by the data output unit 24.

  In the battery evaluation device 100 having such a configuration, the current source is controlled by the controller 14 according to a battery evaluation program of a test pattern in which charging, discharging, resting, and the like are arbitrarily combined according to the evaluation conditions input from the data input unit 22. The battery 10 can be fully charged by performing variable control of the electronic load 11 and each of the electronic loads 12 and 17, so that the battery 10 can be fully charged based on the detection outputs of the main-in current sensor 15, load current sensors 18, and temperature sensors 20. By performing the performance evaluation of the battery pack composed of the above-mentioned batteries 10, it is possible to safely evaluate the difference in the capacity of each battery, the true capacity of the battery pack, the true cycle characteristics of the battery pack, that is, the capacity change due to repeated charging and discharging. And it can be evaluated accurately. In addition, it is possible to simulate the actual use state, and it is possible to analyze market defects, avoid troubles in advance, or perform thorough quality control before shipping.

It is a block diagram of a battery evaluation device concerning the present invention. It is a block diagram of the conventional battery charger.

Explanation of reference numerals

Reference Signs List 10 battery, 11 current source, 12 electronic load, 13 main current sensor, 14 controller, 20 temperature sensor, 21 display unit, 22 data input unit, 23 data holding unit, 24 data output unit, 100 battery evaluation device

Claims (3)

A variable current source and a variable load means provided on a main current path in which a plurality of rechargeable batteries are connected in series and connected in parallel with each other;
A main current sensor for detecting a current value flowing in the main current path, variable load means connected in parallel to each battery, a load current sensor for detecting a current value flowing in each variable load means,
Evaluation means for performing variable control of the variable current source and each variable load means according to a battery evaluation program, and performing performance evaluation based on each current value detected by the main current sensor and the load current sensor;
Output means for outputting an evaluation result by the evaluation means.     2. The battery evaluation device according to claim 1, further comprising a temperature sensor for measuring a temperature of each battery, wherein the evaluation unit evaluates a temperature characteristic based on a detection output from the temperature sensor. An evaluation condition setting input unit, wherein the evaluation unit performs variable control of the variable current source and each variable load unit according to a battery evaluation program corresponding to the evaluation condition set by the setting input unit, and The battery evaluation device according to claim 1, wherein performance evaluation is performed based on each current value detected by the sensor and the load current sensor.

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