JP2012239357A - Battery pack, electronic apparatus, electric power system and electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack capable of predicting the deterioration by using only a piece of measurement data of voltage, current and temperature, and an electronic apparatus, an electric power system and an electric vehicle using the battery pack.SOLUTION: A full charge capacity calculating section calculates the power amount of one or plural cells of a period time from a full charge state to a point when a predetermined discharged capacity is detected, calculates the degree of deterioration of the cells based on the power amount and calculates the full charge capacity corrected according to the calculated degree of deterioration. When the corrected full charge capacity is smaller than the present preset full charge capacity, a full charge capacity updating section updates the preset full charge capacity on the basis of the corrected full charge capacity. The full charge capacity calculating section and the full charge capacity updating section are achieved by using the functions of a microcomputer mounted on the battery pack.

Description

  The present disclosure relates to, for example, a battery pack of a secondary battery, an electronic device using the battery pack, a power system, and an electric vehicle.

  Battery packs including batteries such as lithium ion secondary batteries are widely used as mobile electronic devices, electric vehicles, backup power supplies, and the like. A battery pack is defined as a configuration in which one or a plurality of secondary batteries and a protection circuit including a detection unit for detecting battery voltage, current, and temperature are integrated by an exterior such as a laminate film or a synthetic resin case. The The battery pack may have an authentication circuit.

  Battery packs are widely used to inform the user of the remaining capacity of the battery pack by flashing a light emitting diode or the like on the electronic device body. However, there are cases where more accurate remaining capacity display is required. As an electronic device, for example, in the case of a camcorder for a broadcasting station (camcorder: an abbreviation for camera and recorder), an accurate remaining capacity display is necessary because it is for business use.

  As a method for detecting the remaining capacity of the secondary battery, an integration method for obtaining the charge capacity by integrating the current or the electric energy is known. Measure the voltage and current when using the secondary battery, and integrate the power used by the voltage x current. A ratio between the integrated power and the fully charged capacity of the secondary battery is obtained, and the capacity retention rate or remaining capacity ratio of the secondary battery is calculated.

  In general, the full charge capacity of a lithium ion secondary battery decreases due to deterioration. As the battery pack is used, its deterioration progresses and the capacity that can be discharged from a new (unused) battery decreases even if it is fully charged. When the remaining capacity is calculated in the microcomputer mounted on the battery pack, data reliability such as full charge capacity and remaining capacity is lowered due to deterioration.

  In order to prevent deterioration of remaining capacity due to battery deterioration, the relationship between charge count and cycle count and capacity deterioration is acquired in advance from test data, and the full charge capacity value follows the charge count and cycle count. Has been updated. However, the deterioration state of the battery pack is not constant due to the use frequency of the user and the influence of the use environment. For this reason, an accurate deterioration state cannot be obtained simply by the number of uses.

  Furthermore, the accurate full charge capacity can be measured by discharging the remaining capacity to 0 and then charging it to the fully charged state. However, in this method, the user needs to intentionally discharge the fully charged battery pack to the end, and there is a problem that places an extra burden on the user.

  Patent Document 1 describes that the remaining capacity is accurately calculated using the characteristic that the internal impedance of the battery increases due to deterioration. In Patent Document 1, after a battery is once put into a resting state, it is discharged or charged for a short time with a constant current, and an internal resistance is obtained from a change in terminal voltage before and after the discharging or charging to calculate a remaining capacity.

JP 2000-67932 A

  The thing of patent document 1 needs to perform discharge and charge for a short time after putting it in a rest state, and it is required to perform operation | movement (process) different from normal charging / discharging operation | movement.

  Therefore, it is an object of the present disclosure to provide a battery pack and a battery that can predict deterioration only by using voltage, current, and temperature measurement data, without the need to construct a special circuit or system for measuring internal impedance. An object is to provide an electronic device, a power system, and an electric vehicle that use a pack.

The present disclosure includes one or more batteries;
Obtain the amount of power during the period from when the battery is fully charged until the specified discharge capacity is detected, calculate the degree of battery deterioration from the amount of power, and calculate the full charge capacity corrected by the calculated degree of deterioration. A full charge capacity calculation unit to calculate,
When the corrected full charge capacity is smaller than the current set full charge capacity, the battery pack includes a full charge capacity update unit that updates the set full charge capacity with the corrected full charge capacity.
Preferably, the full charge capacity calculation unit calculates the amount of electric power in which the heat loss due to the temperature rise in the period is corrected.

The method of the present disclosure obtains the amount of power during a period from when the one or more batteries are fully charged until a predetermined discharge capacity is detected, and calculates the degree of deterioration of the battery from the amount of power.
Calculate the full charge capacity corrected by the calculated degree of deterioration,
When the corrected full charge capacity is smaller than the current set full charge capacity, the full charge capacity calculation method updates the set full charge capacity with the corrected full charge capacity.

The present disclosure is an electronic device that includes the battery pack described above and receives power supply from the battery pack.
The present disclosure is a power system in which the above-described battery pack is charged by a power generation device that generates power from renewable energy.
The present disclosure is an electric vehicle including a conversion device that receives electric power from the battery pack and converts the power into a driving force of the vehicle, and a control device that performs information processing related to vehicle control based on information related to the battery pack. .
The present disclosure includes a power information transmission / reception unit that transmits and receives signals to and from other devices via a network.
It is an electric power system which performs charge / discharge control of the battery pack mentioned above based on the information which the electric power information transmission / reception part received.
The present disclosure is an electric power system that receives electric power from the above-described battery pack and supplies electric power to the battery pack from a power generation device or an electric power network.

  According to the embodiment, it is not necessary to construct a special circuit or system for measuring the internal resistance of the battery, and measurement data of voltage, current, and temperature generally used in a battery pack remaining capacity calculation system. It is possible to obtain information on the degree of deterioration only by using. The degree of deterioration can be automatically measured without requiring any special operation by the user.

It is a basic diagram which shows the change of the discharge voltage of the battery pack from which a deterioration state differs. It is a basic diagram which shows the relationship between electric energy and capacity | capacitance retention. It is an example of the data which shows the electric energy at the time of changing a deterioration rate, environmental temperature, and discharge load. FIG. 4 is a schematic diagram obtained by adding temperature rise data to the data of FIG. 3. It is a basic diagram which added the electric energy after heat loss correction | amendment with respect to the data of FIG. It is a basic diagram which shows the relationship between the electric energy after heat loss correction | amendment, and a capacity | capacitance retention. It is a basic diagram which shows the capacity | capacitance retention calculated from the electric energy after heat loss correction | amendment. It is a block diagram which shows the structural example of the battery pack of one Embodiment. It is a basic diagram which shows an example of the display by a remaining capacity display part. It is a flowchart which shows the flow of the process of one Embodiment. It is a flowchart which shows the flow of a process of the modification of one embodiment. It is a block diagram for demonstrating the application example of a battery pack. It is a block diagram for demonstrating the application example of a battery pack.

Hereinafter, embodiments will be described. The description will be given in the following order.
<Deterioration detection and update of set full charge capacity value>
<Battery pack configuration>
<Process flow in battery pack>
<Application example>
<Modification>
The embodiments described below are preferable specific examples, and various technically preferable limitations are given. However, the scope of this disclosure is particularly limited in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

<Deterioration detection and update of set full charge capacity value>
A microcomputer is mounted on the battery pack, and information on voltage, current, and temperature measured periodically is supplied to the microcomputer. The remaining capacity is calculated by subtracting, for example, the integrated value (mAh) of the discharge current from the full charge capacity value held in the battery pack by the microcomputer. In the case of a new battery pack, the nominal full charge capacity is stored on the microcomputer program or in a non-volatile memory.

  FIG. 1 shows an example of changes in discharge voltage of a plurality of battery packs having different degrees of deterioration. In FIG. 1, reference symbol Ca indicates a change curve of the discharge voltage of a new battery pack. The full charge capacity is 1950 mAh. Reference symbol Cb indicates a change curve of the discharge voltage of the battery pack having a deterioration rate of 30%. The full charge capacity is (1950 mAh × 0.7 = 1365 mAh). Reference symbol Cc indicates a change curve of the discharge voltage of a battery pack having a deterioration rate of 50%. The full charge capacity is (1950 mAh × 0.5 = 975 mAh).

  The microcomputer calculates the amount of electric power by integrating the electric power of “current × voltage”. In the present disclosure, the amount of electric power during a period from a fully charged state to a time when a predetermined discharge capacity is detected is obtained. As an example, the predetermined discharge capacity is 400 mAh. In FIG. 1, the shaded area corresponds to the amount of power. The amount of power decreases as the degree of deterioration progresses as compared with a new battery pack. This difference in electric energy occurs because the internal impedance of the battery increases due to deterioration.

  An appropriate value is set as the value of the predetermined discharge capacity. In the present disclosure, the remaining capacity can be automatically calculated without any special operation when the user uses it. If the value of the predetermined discharge capacity is too large, the value may reach that value when the user uses it. Due to the small amount, there arises a problem that the remaining capacity cannot be calculated. Conversely, if the value of the predetermined discharge capacity is too small, there is a problem that the accuracy of the calculated remaining capacity is lowered. From such a point, for example, the predetermined discharge capacity is set to 400 mAh. This value is an example, and other values can be set as long as they do not cause the above-described problem.

  The amount of electric power during the period from the start of discharge in the fully charged state to the discharge capacity of 400 mAh (hereinafter referred to as measured electric energy as appropriate) is measured. The relationship between the measured electric energy and the capacity retention rate is substantially linear as shown in FIG. The capacity retention rate is a ratio when the full charge capacity of a new (unused) battery pack is 100%. The deterioration rate (%) is the rate of decrease in full charge capacity from a new battery pack. Furthermore, FIG. 1 and FIG. 2 are the characteristics regarding a certain kind of battery pack. There is almost no variation in the characteristics of the same type of battery pack. Therefore, the capacity retention rate (deterioration rate) can be obtained by measuring the electric energy.

  However, the amount of electric power varies depending on the discharge load and temperature (the temperature measured by a temperature detection element such as a thermistor inside the battery pack, hereinafter referred to as the environmental temperature as appropriate), and therefore the amount of electric power during the period until 400 mAh is discharged. Cannot be used as is. FIG. 3 shows changes in the electric energy due to the environmental temperature and the discharge load. FIG. 3A relates to a new battery pack, FIG. 3B relates to a battery pack with a degradation rate of 30%, and FIG. 3C relates to a battery pack with a degradation rate of 50%. Among the test data shown in FIG. 3, for example, three pieces of data (in the case of environmental temperature = 23 ° C. and discharge load = 15 W) are plotted on the graph of (capacity retention ratio vs. electric energy) in FIG. It is a graph.

  As can be seen from FIG. 3, in the case of battery packs having the same deterioration rate, the amount of power increases as the environmental temperature increases, and the amount of power decreases as the discharge load increases. However, since the amount of power decreases as the deterioration rate increases, the deterioration rate cannot be determined accurately only from the amount of power. For example, in the case of a new battery pack (FIG. 3A), in the case of (environmental temperature = 15 ° C., discharge load = 25 W) (* is added to the corresponding row), the electric energy is 6.0382 Wh. On the other hand, in the case of a battery pack (FIG. 3B) with a degradation rate of 30% (* is added to the corresponding row), and in the case of (environmental temperature = 35 ° C., discharge load = 10 W), the electric energy is 6.09797 Wh. . Accordingly, the amounts of power are substantially equal, and the degree of deterioration cannot be determined only by the amount of power.

  A detailed analysis of changes in the amount of electricity due to the external environment revealed that the effect of temperature is related. FIG. 4 shows data obtained by adding temperature rise data from the start of discharge in the fully charged state to the discharge capacity of 400 mAh with respect to the data of FIG. Comparing the two data of the above-mentioned conditions (data in the rows added with * in FIG. 4A and FIG. 4B), the electric energy is almost the same, but the temperature rise is about (6 ° C. and 3.3 ° C.). A difference of 3 ° C occurs.

  That is, even if the amount of power is the same, the amount of power loss due to temperature rise is different. By adding the power loss due to the temperature rise to the power amount measurement, the deterioration rate can be measured more accurately. Specific temperature correction is performed by adding a heat loss, which is a product of a coefficient set for each battery with respect to the temperature rise [° C.], to the electric energy. This coefficient is a value calculated from a temperature increase obtained through experiments, and is a value that varies depending on the type of battery. As an example, the temperature rise [° C.] × 0.066 is added to the electric energy (FIGS. 3 and 4) as a heat loss. FIG. 5 shows the electric energy after the heat loss correction. The degree of deterioration is obtained from the amount of power after this heat loss correction.

From the test data shown in FIG. 5, the relationship between the electric energy after the heat loss correction and the capacity retention rate is obtained. Furthermore, a calculation formula approximated to the linear expression is obtained. For example, three pieces of data (in the case of environmental temperature = 23 ° C. and discharge load = 15 W) are plotted on a graph of (capacity retention ratio vs. electric energy) shown in FIG. The line connecting the three points is almost a straight line. This straight line is approximated by the following linear expression. Since this equation differs depending on the type of battery pack to be used, an equation is appropriately set for each battery pack and stored in advance in a memory or the like in the battery pack.
Capacity retention [%] y = 226.13 × electric power x [Wh] −1346.3 (Formula 1)
However, when the capacity retention determined by the above formula is 50% or less, it is 50%, and when it is 100% or more, it is 100%.

The full charge capacity [mAh] is obtained as follows.
Full charge capacity [mAh] = nominal capacity × capacity retention [%] / 100 (Formula 2)
The nominal capacity is the fully charged capacity when new. The nominal capacity is 1950 mAh, for example.

  In the test data shown in FIGS. 3 to 5, the discharge load is in the range of 10 W to 25 W, and the environmental temperature is in the range of 15 ° C. to 35 ° C. That is, there are 12 combinations of environmental temperature and discharge load. However, in this embodiment, the capacity retention rate is calculated using the above-described linear equation (Equation 1) for combinations other than (environmental temperature = 23 ° C., discharge load = 15 W). ing.

  The calculated capacity retention values are shown in FIG. The capacity retention rate in the case of (environmental temperature = 23 ° C., discharge load = 15 W) has a small error. For other environmental temperature and discharge load combinations, the error is considered to be within an acceptable range. The capacity retention rate can be calculated within an error range of about ± 10%. However, in the case where the environmental temperature exceeds the set range, for example, 0 ° C. and 45 ° C., the error exceeds the allowable range. The same applies to the discharge load. Therefore, the process for calculating the capacity retention rate is performed only within a predetermined range of the discharge load and the environmental temperature. In addition, the specific value of the setting range of discharge load and environmental temperature is an example.

  As another method, regarding the 12 combinations of the environmental temperature and the discharge load, the graph of FIG. 6 and the above-described primary expression are obtained in advance, and one of them is selected according to the environmental temperature and the discharge load when measuring the electric energy. It is also possible to calculate the capacity retention rate by selecting the following equation. This method improves accuracy, but increases the processing load.

  Further, the full charge capacity is corrected according to Equation 2 based on the calculated capacity retention rate. The corrected full charge capacity is referred to as a corrected full charge capacity. In order to calculate the remaining capacity, the full charge capacity is stored in the microcomputer (program) or the nonvolatile memory. This full charge capacity is referred to as a set full charge capacity. When the corrected full charge capacity is smaller than the current set full charge capacity, the set full charge capacity is updated so that the corrected full charge capacity becomes the set full charge capacity. . When updating is performed, the set full charge capacity is gradually changed. For example, in one update, the amount of change in the set full charge capacity is fixed to 0.5% of the nominal full charge capacity. This is to prevent an excessive change in the full charge capacity due to a calculation error and to prevent the user from feeling uncomfortable by updating the full charge capacity smoothly.

  The updated set full charge capacity is a capacity capable of discharging at normal temperature (25 ° C.) and a discharge load (15 W). This is because the discharge capacity when standard discharge is performed in a normal temperature environment from full charge is defined as full charge capacity. This standard discharge uses 15 W as a discharge load. When calculating the remaining capacity, the remaining capacity is calculated on the basis of the full charge capacity value and taking into account the temperature and the discharge load.

  The capacity retention rate calculating operation described above is automatically performed by the microcomputer when the discharge load and the environmental temperature are values within the set range, and discharge is performed up to a discharge capacity of 400 mAh. Therefore, it is not necessary for the user to perform a special operation, and capacity deterioration can be automatically detected within a normal use range.

  Using the obtained set full charge capacity, the microcomputer can calculate the remaining capacity in units of mAh by an integration method for obtaining the charge capacity by integrating the existing current or electric energy. The main device or the charger connected to the battery pack acquires the remaining capacity data and the set full charge capacity data through communication with the battery pack. By referring to the set full charge capacity data, it can be determined how much deterioration has progressed.

<Battery pack configuration>
FIG. 8 shows a configuration of a battery pack using a secondary battery such as a lithium ion battery. The battery pack is attached to the charger during charging, and the + terminal 1 and the − terminal 2 are connected to the + terminal and the − terminal of the charger, respectively, and charging is performed. When the electronic device is used, the + terminal 1 and the − terminal 2 are connected to the + terminal and the − terminal of the electronic device as in charging, and discharging is performed. The electronic device is a commercial camcorder, a mobile phone, a notebook PC (personal computer), or the like. Furthermore, as will be described later, there are cases in which it is connected to an electric vehicle or an in-home power system in addition to the portable device.

  The battery pack mainly includes a battery 7, a microcomputer 10, an analog front end 11, a protection circuit 12, a switch unit 4, and communication terminals 3a and 3b. The battery 7 is a secondary battery such as a lithium ion battery, in which four secondary batteries are connected in series. However, the present disclosure can be applied not only to a series connection of four batteries but also to a configuration in which one or a plurality of batteries are connected in series and / or in parallel.

The microcomputer 10 calculates the degree of deterioration, functions as a full charge capacity calculation unit for calculating the full charge capacity corrected according to the degree of deterioration, and the full charge capacity for updating the set full charge capacity with the corrected full charge capacity. And a function as a charge capacity update unit. Specifically, the microcomputer 10 has a configuration of, for example, an MCU (Micro Controller Unit). M
A CU is an embedded microprocessor in which a computer system is integrated into one integrated circuit. Unlike a general microprocessor, the MCU has many peripheral functions such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and I / O related functions.

  The microcomputer 10 uses the voltage value and current value input from the analog front end 11 to perform processing such as calculation of the capacity retention rate and calculation of the remaining capacity as described above. An environmental temperature (battery temperature) is measured by a temperature detection element (for example, a thermistor) 8. The measured environmental temperature data is supplied to the microcomputer 10. Further, a nonvolatile memory such as an EEPROM (Electrically Erasable and Programmable Read Only Memory) 13 is connected to the microcomputer 10. The EEPROM 13 prevents data loss due to the stop of power supply to the microcomputer 10.

  The analog front end 11 measures the voltage of each battery 7 in the battery pack and supplies the measured value to the microcomputer 10. Further, a current is detected using the current detection resistor 9, and the detected current is supplied to the current integrating unit 14. The current integrating unit 14 integrates the discharge current and detects the discharge capacity. The discharge capacity is supplied to the microcomputer 10. Furthermore, the analog front end 11 also has a function as a regulator that stabilizes the voltage of the battery 7 and generates a power supply voltage.

  The protection circuit 12 sends a control signal to the switch unit 4 when the voltage of any one of the batteries 7 becomes an overcharge detection voltage or when the voltage of the battery 7 becomes equal to or lower than the overdischarge detection voltage. Prevents overcharge and overdischarge. In the case of a lithium ion battery, the overcharge detection voltage is determined to be 4.2 V ± 0.5 V, for example, and the overdischarge detection voltage is determined to be 2.4 V ± 0.1 V. Further, an overcurrent protection operation is performed by the protection circuit 12.

The switch unit 4 includes a charge control FET (Field Effect Transistor) 5 and a discharge control FET.
6. When the battery voltage becomes the overcharge detection voltage, the charging control FET 5 is turned off and the charging current is controlled not to flow. Note that after the charge control FET 5 is turned off, only discharge is possible through the parasitic diode 5a.

  When the battery voltage reaches the overdischarge detection voltage, the discharge control FET 6 is turned off and the discharge current is controlled not to flow. Note that after the discharge control FET 6 is turned off, only charging is possible through the parasitic diode 6a.

  The communication terminals 3a and 3b are for transmitting battery capacity information to the device when the communication terminals 3a and 3b are attached to the electronic device. As a communication path connecting the battery pack and the electronic device, SMBus (System Management Bus) is used as a standard system. Further, the terminal 3 c is a terminal connected to the ID resistor 16. Based on the resistance value of the ID resistor 16, it is determined in the charger or the electronic device whether or not the battery pack is normal.

  Furthermore, a remaining capacity display unit 15 including four LEDs (Light Emitting Diodes) L1 to L4 is connected to the microcomputer 10. The remaining capacity display unit 15 is turned on by operating a remaining capacity switch provided in an electronic device connected to the battery pack, for example. The remaining capacity display unit 15 of the battery pack is provided in a part of the casing of the battery pack so that it can be seen from the outside even when the battery pack is mounted on the electronic device. The switch down is notified to the battery pack by communication.

  As shown in FIG. 9, the LEDs of the remaining capacity display unit 15 emit light selectively according to the absolute charging rate. The absolute charging rate is a charging rate with respect to a nominal capacity. For example, in the case of a battery whose deterioration is progressing by 20% to 40% according to the display of the remaining capacity display unit 15, only three LEDs (L1 to L3) are lit even when fully charged. It becomes possible to judge the degree in an instant.

<Process flow in battery pack>
The operation of the battery pack will be described with reference to the flowchart shown in FIG. The series of processes shown in the figure is repeated with a predetermined period, for example, 1 second. That is, infinite loop processing is performed in the microcomputer program. Unless otherwise specified, the following processing is performed in the microcomputer 10.

  The process starts when discharging starts from the fully charged state. In the first step S <b> 1 of the process, the microcomputer 10 measures the voltage, current, and temperature via the analog front end 11. The measurement cycle is 1 second. In step S2, power is calculated by “current × voltage” for each measurement cycle. When the temperature rise occurs, the result of temperature rise [° C.] × 0.66 is added to the electric energy as heat loss.

  In step S3, the remaining capacity is calculated. For example, the remaining capacity is calculated by subtracting the discharge capacity from the set full charge capacity.

  The degree of deterioration is examined by the processing after step S4. In step S4, it is determined whether or not discharge has been started from full charge and a predetermined discharge capacity (for example, 400 mAh) has been reached. If the determination result is negative, the process returns to step S1 (voltage, current, temperature measurement). If the determination result of step S4 is affirmative, the process proceeds to step S5.

  In step S5, it is determined whether or not the environmental temperature measured in step S1 is within a range (15 ° C. to 35 ° C.). If the determination result is negative, the process returns to step S1 (voltage, current, temperature measurement). If the determination result of step S5 is affirmative, the process proceeds to step S6.

  In step S6, it is determined whether or not the discharge load obtained from the voltage and current measured in step S1 is within a range (10 W to 25 W). If the determination result is negative, the process returns to step S1 (voltage, current, temperature measurement). If the determination result of step S6 is affirmative, the process proceeds to step S7.

  In step S7, the capacity retention rate [%] is calculated by the above-described equation 1, and the fully charged capacity [mAh] in which the deterioration is corrected is calculated by the equation 2 from the obtained capacity retention rate. In step S8, the full charge capacity whose deterioration has been corrected is compared with the currently set full charge capacity. That is, it is determined whether or not the full charge capacity whose deterioration has been corrected is smaller than the currently set full charge capacity. If the determination result is negative, the process returns to step S1 (voltage, current, temperature measurement). If the determination result of step S8 is affirmative, the process proceeds to step S9.

  In step S9, 0.5% of the nominal full charge capacity is subtracted from the currently set full charge capacity. However, the minimum value of the calculated full charge capacity is set to 50% of the nominal full charge capacity so as not to be smaller than this. If it becomes 50% or less, an alarm such as a display for notifying the user that it has become 50% or less may be provided. When the nominal full charge capacity is 1950 mAh, for example, the set full charge capacity is decreased in steps of 9.75 mAh. In this case, the lower limit is 975 mAh (deterioration rate is 50%). Thus, the set full charge capacity stored in the program of the microcomputer 10 or in the nonvolatile memory 13 is updated.

  Further, although omitted in FIG. 10, when the microcomputer 10 receives the operation of the remaining capacity switch, the remaining capacity display unit 15 is charged with respect to the nominal full charge capacity by the selective light emission of the four LEDs. Display rate. Thereby, for example, the degree of deterioration can be notified to the user.

  Furthermore, load fluctuations are large in applications such as electric tools and electric vehicles. For example, when discharging is performed with a large load of 100 W until just before the discharge capacity reaches 400 mAh, and the load becomes a value within the range of 10 W to 25 W at 400 mAh, the deterioration calculation result has a large error. There's a problem.

  For such a problem, as shown in FIG. 11, a process of providing step S11 instead of step S6 (FIG. 10) may be performed. Processing other than step S11 is the same as that in FIG. Step S11 is processing to determine whether or not the load until reaching 400 mAh is within a range (10 W to 25 W). If the determination result is negative, the process returns to step S1 (voltage, current, temperature measurement). If the determination result of step S11 is affirmative, the process proceeds to the process of step S7 (deterioration calculation and full charge capacity calculation).

The battery pack according to the present disclosure described above has the following advantages.
-The user does not need to perform any special operation, and the capacity deterioration can be automatically detected in the normal use range.
-The discharge load at the time of measuring electric energy may not be a constant load. In the example described above, the discharge load is in the range of 10W to 25W.
-The environmental temperature at the time of electric energy measurement does not need to be predetermined temperature, and should just exist in the range of 15 degreeC-35 degreeC in the example mentioned above.
The capacity retention rate can be calculated using a linear equation calculated in advance using only voltage, current, and temperature data. Newly, there is no need to have a data table inside the microcomputer or in the non-volatile memory.
The update of the degradation state is to rewrite the set full charge capacity, and is updated by subtracting a value of 0.5% of the nominal full charge capacity from the set full charge capacity. Therefore, an excessive change in the full charge capacity can be suppressed, and a smooth update that does not give the user a sense of incongruity can be performed.
-The accuracy of the set full charge capacity is increased, and the accuracy of calculation of the remaining capacity using the set full charge capacity can be increased.
The deterioration state can be determined by the display on the remaining capacity display unit 15 on the user side. Therefore, it is possible to easily determine whether the battery pack has failed or has reached the end of its life.
. Troubles when using the main unit due to insufficient battery pack capacity can be prevented.

In addition, this indication can also take the following structures.
(1) one or more batteries;
The amount of electric power during a period from when the battery is fully charged until a predetermined discharge capacity is detected is obtained, the degree of deterioration of the battery is calculated from the amount of electric power, and the full amount corrected according to the calculated degree of deterioration. A full charge capacity calculation unit for calculating the charge capacity;
A battery pack comprising: a full charge capacity update unit that updates the set full charge capacity with the corrected full charge capacity when the corrected full charge capacity is smaller than a current set full charge capacity.
(2) The battery pack according to (1), wherein the full charge capacity calculation unit corrects the electric energy by heat loss due to a temperature rise in the period.
(3) The full charge capacity calculation unit obtains a heat loss by a product of a temperature rise value in the period and a coefficient set for each battery, and corrects the electric energy by the heat loss (1) or The battery pack according to (2).
(4) The battery pack according to (1), (2), or (3), wherein the full charge capacity calculation unit calculates the full charge capacity when the environmental temperature is within a preset range.
(5) The full charge capacity calculation unit according to (1), (2), (3), or (4), wherein the full charge capacity is calculated when a discharge load is within a preset range. Battery pack.
(6) The full charge capacity update unit corrects the set full charge capacity value so that the set full charge capacity value gradually changes. (1), (2), (3), (4) or The battery pack according to (5).
(7) The full charge capacity calculation unit calculates the degree of deterioration of the battery by an approximate expression (A × electric energy−B) based on the electric energy and values A and B obtained in advance. , (2), (3), (4), (5) or (6).

<Application example>
The present disclosure is an electronic device that includes the battery pack described above and receives power supply from the battery pack.
The present disclosure is a power system in which the above-described battery pack is charged by a power generation device that generates power from renewable energy.
The present disclosure is an electric vehicle including a conversion device that receives electric power from the battery pack and converts the power into a driving force of the vehicle, and a control device that performs information processing related to vehicle control based on information related to the battery pack. .
The present disclosure is a power system that includes a power information transmission / reception unit that transmits / receives a signal to / from another device via a network, and performs charge / discharge control of the battery pack described above based on information received by the transmission / reception unit.
The present disclosure is an electric power system that receives electric power from the above-described battery pack and supplies electric power to the battery pack from a power generation device or an electric power network.
"Storage system in a house as an application example"
An example in which the present disclosure is applied to a residential power storage system will be described with reference to FIG. For example, in the power storage system 100 for the house 101, electric power is stored from the centralized power system 102 such as the thermal power generation 102a, the nuclear power generation 102b, and the hydroelectric power generation 102c through the power network 109, the information network 112, the smart meter 107, the power hub 108, and the like. Supplied to the device 103. At the same time, power is supplied to the power storage device 103 from an independent power source such as the home power generation device 104. The electric power supplied to the power storage device 103 is stored. Electric power used in the house 101 is fed using the power storage device 103. The same power storage system can be used not only for the house 101 but also for buildings.

  The house 101 is provided with a power generation device 104, a power consumption device 105, a power storage device 103, a control device 110 that controls each device, a smart meter 107, and a sensor 111 that acquires various types of information. Each device is connected by a power network 109 and an information network 112. As the power generation device 104, a solar cell, a fuel cell, or the like is used, and the generated power is supplied to the power consumption device 105 and / or the power storage device 103. The power consuming device 105 is a refrigerator 105a, an air conditioner 105b, a television receiver 105c, a bath 105d, and the like. Furthermore, the electric power consumption device 105 includes an electric vehicle 106. The electric vehicle 106 is an electric vehicle 106a, a hybrid car 106b, and an electric motorcycle 106c.

  The battery pack of the present disclosure described above is applied to the power storage device 103. The power storage device 103 includes a secondary battery or a capacitor. For example, a lithium ion battery is used. The lithium ion battery may be a stationary type or used in the electric vehicle 106. The smart meter 107 has a function of measuring the usage amount of commercial power and transmitting the measured usage amount to an electric power company. The power network 109 may be any one or a combination of DC power supply, AC power supply, and non-contact power supply.

  The various sensors 111 are, for example, human sensors, illuminance sensors, object detection sensors, power consumption sensors, vibration sensors, contact sensors, temperature sensors, infrared sensors, and the like. Information acquired by the various sensors 111 is transmitted to the control device 110. Based on the information from the sensor 111, the weather condition, the human condition, etc. can be grasped, and the power consumption device 105 can be automatically controlled to minimize the energy consumption. Furthermore, the control device 110 can transmit information regarding the house 101 to an external power company or the like via the Internet.

The power hub 108 performs processing such as branching of power lines and DC / AC conversion. As a communication method of the information network 112 connected to the control device 110, UART (Universal Asynchron
There are a method using a communication interface such as ous Receiver-Transceiver (transmission / reception circuit for asynchronous serial communication) and a method using a sensor network based on a wireless communication standard such as Bluetooth, ZigBee, Wi-Fi. The Bluetooth method is applied to multimedia communication and can perform one-to-many connection communication. ZigBee uses the physical layer of IEEE (Institute of Electrical and Electronics Engineers) 802.15.4. IEEE 802.15.4 is the name of a short-range wireless network standard called PAN (Personal Area Network) or W (Wireless) PAN.

The control device 110 is connected to an external server 113. The server 113 may be managed by any one of the house 101, the power company, and the service provider. The information transmitted and received by the server 113 is, for example, information related to power consumption information, life pattern information, power charges, weather information, natural disaster information, and power transactions. These pieces of information may be transmitted / received from a power consuming device (for example, a television receiver) in the home, or may be transmitted / received from a device outside the home (for example, a mobile phone). Such information may be displayed on a device having a display function, such as a television receiver, a mobile phone, or a PDA (Personal Digital Assistants).

  A control device 110 that controls each unit includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and is stored in the power storage device 103 in this example. The control device 110 is connected to the power storage device 103, the home power generation device 104, the power consumption device 105, various sensors 111, the server 113 and the information network 112, for example, a function of adjusting the amount of commercial power used and the amount of power generation have. In addition, you may provide the function etc. which carry out an electric power transaction in an electric power market.

  As described above, the electric power can be stored not only in the centralized power system 102 such as the thermal power 102a, the nuclear power 102b, and the hydraulic power 102c but also in the power generation device 104 (solar power generation, wind power generation). it can. Therefore, even if the generated power of the home power generation device 104 fluctuates, it is possible to perform control such that the amount of power to be sent to the outside is constant or discharge is performed as necessary. For example, the electric power obtained by solar power generation is stored in the power storage device 103, and midnight power with a low charge is stored in the power storage device 103 at night, and the power stored by the power storage device 103 is discharged during a high daytime charge. You can also use it.

  In this example, the control device 110 is stored in the power storage device 103. However, the control device 110 may be stored in the smart meter 107, or may be configured independently. Furthermore, the power storage system 100 may be used for a plurality of homes in an apartment house, or may be used for a plurality of detached houses.

"Vehicle power storage system as an application example"
An example in which the present disclosure is applied to a power storage system for a vehicle will be described with reference to FIG. FIG. 13 schematically illustrates an example of a configuration of a hybrid vehicle that employs a series hybrid system to which the present disclosure is applied. The series hybrid system is a vehicle that runs on a power driving force conversion device using electric power generated by a generator driven by an engine or electric power once stored in a battery.

  The hybrid vehicle 200 includes an engine 201, a generator 202, a power driving force conversion device 203, driving wheels 204a, driving wheels 204b, wheels 205a, wheels 205b, a battery 208, a vehicle control device 209, various sensors 210, and a charging port 211. Is installed. The battery pack of the present disclosure described above is applied to the battery 208.

  The hybrid vehicle 200 runs using the power driving force conversion device 203 as a power source. An example of the power driving force conversion device 203 is a motor. The electric power / driving force converter 203 is operated by the electric power of the battery 208, and the rotational force of the electric power / driving force converter 203 is transmitted to the driving wheels 204a and 204b. In addition, by using a direct current-alternating current (DC-AC) or reverse conversion (AC-DC conversion) where necessary, the power driving force conversion device 203 can be applied to either an alternating current motor or a direct current motor. The various sensors 210 control the engine speed via the vehicle control device 209 and control the opening (throttle opening) of a throttle valve (not shown). The various sensors 210 include a speed sensor, an acceleration sensor, an engine speed sensor, and the like.

  The rotational force of the engine 201 is transmitted to the generator 202, and the electric power generated by the generator 202 by the rotational force can be stored in the battery 208.

  When the hybrid vehicle decelerates by a braking mechanism (not shown), the resistance force at the time of deceleration is applied as a rotational force to the power driving force conversion device 203, and the regenerative power generated by the power driving force conversion device 203 by this rotational force is applied to the battery 208. Accumulated.

  The battery 208 is connected to a power source outside the hybrid vehicle, so that it can receive power from the external power source using the charging port 211 as an input port and store the received power.

  Although not shown, an information processing apparatus that performs information processing related to vehicle control based on information related to the secondary battery may be provided. As such an information processing apparatus, for example, there is an information processing apparatus that displays a remaining battery capacity based on information on the remaining battery capacity.

  In the above description, a series hybrid vehicle that runs on a motor using electric power generated by a generator that is driven by an engine or electric power that is temporarily stored in a battery has been described as an example. However, the present disclosure is also effective for a parallel hybrid vehicle that uses both the engine and motor outputs as the drive source, and switches between the three modes of running with the engine alone, running with the motor alone, and engine and motor running as appropriate. Applicable. Furthermore, the present disclosure can be effectively applied to a so-called electric vehicle that travels only by a drive motor without using an engine.

<Modification>
As mentioned above, although embodiment of this application was described concretely, it is not limited to each above-mentioned embodiment, Various deformation | transformation based on the technical idea of this indication is possible. For example, in the flowchart shown in FIG. 10, it may be determined whether or not the environmental temperature or the discharge load is within a predetermined range as the process before the update of the set full charge capacity in step S9.

4 ... Switch unit 7 ... Battery 8 ... Temperature detection element 9 ... Current detection resistor 10 ... Microcomputer 14 ... Current integration unit 15 ... Remaining capacity display unit

Claims (13)

One or more batteries;
The amount of electric power during a period from when the battery is fully charged until a predetermined discharge capacity is detected is obtained, the degree of deterioration of the battery is calculated from the amount of electric power, and the full amount corrected according to the calculated degree of deterioration. A full charge capacity calculation unit for calculating the charge capacity;
A battery pack comprising: a full charge capacity update unit that updates the set full charge capacity with the corrected full charge capacity when the corrected full charge capacity is smaller than a current set full charge capacity.   The battery pack according to claim 1, wherein the full charge capacity calculation unit corrects the amount of power by heat loss due to a temperature rise during the period.   2. The battery pack according to claim 1, wherein the full charge capacity calculation unit obtains heat loss by a product of a temperature rise value in the period and a coefficient set for each battery, and corrects the electric energy by the heat loss. .   The battery pack according to claim 1, wherein the full charge capacity calculation unit calculates the full charge capacity when the environmental temperature is within a preset range.   The battery pack according to claim 1, wherein the full charge capacity calculation unit calculates the full charge capacity when a discharge load is within a preset range.   The battery pack according to claim 1, wherein the full charge capacity update unit corrects the set full charge capacity value so that the set full charge capacity value gradually changes.   2. The battery according to claim 1, wherein the full charge capacity calculation unit calculates a degree of deterioration of the battery by an approximate expression (A × electric energy−B) based on the electric energy and values A and B obtained in advance. pack. Determining the amount of power during a period from when the one or more batteries are fully charged until a predetermined discharge capacity is detected, and calculating the degree of deterioration of the battery from the amount of power;
Calculate the full charge capacity corrected by the calculated degree of deterioration,
A full charge capacity calculation method for updating the set full charge capacity with the corrected full charge capacity when the corrected full charge capacity is smaller than a currently set full charge capacity.   The electronic device which has a battery pack in any one of Claims 1-7, and receives supply of electric power from the said battery pack.   The electric power system with which the battery pack in any one of Claims 1-7 is charged by the electric power generating apparatus which produces electric power from renewable energy.   A conversion device that receives supply of electric power from the battery pack according to any one of claims 1 to 7 and converts it into a driving force of a vehicle, and a control device that performs information processing related to vehicle control based on information related to the battery pack An electric vehicle. A power information transmission / reception unit that transmits / receives signals to / from other devices via a network,
The electric power system which performs charging / discharging control of the battery pack in any one of Claims 1-7 based on the information which the said electric power information transmission / reception part received.   The electric power system which receives supply of electric power from the battery pack in any one of Claims 1-7, and supplies electric power to the said battery pack from an electric power generating apparatus or an electric power network.

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