JP2006164820A - Battery pack and charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To charge a battery pack with an appropriate charging voltage by receiving battery information stored in the battery pack by a charger and by automatically determining the charging voltage of the battery pack based on the received battery information. <P>SOLUTION: Battery information related to this battery pack 40 is stored in an EEPROM 10. The battery information is transmitted to this charger 50 by wireless communication. The charger 50 determines whether the battery pack 50 is chargeable or not by using the received battery information and usable battery information of the battery pack previously stored in the EEPROM 24. When it is chargeable, a voltage supplied from a charging circuit 26 is converted to a charging voltage suitable for the battery pack 40 in a voltage transformation circuit 25 and supplied to the battery pack 40. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery pack and a charger that determine whether or not charging is possible between a battery pack and a charger using wireless communication.

  Due to the remarkable development of portable electronic technology in recent years, portable electronic devices such as mobile phones and notebook personal computers are considered indispensable to support a highly information-oriented society. Currently, many battery packs used in such portable electronic devices have different shapes and capacities. In order to charge these battery packs, a charger corresponding to each battery pack is required.

  If the charging voltage required by the battery pack differs from the charging voltage of the charger, for example, if a charger with a charging voltage higher than the charging voltage of the battery is used, an excessive current may flow through the battery pack. There was a problem that safety was not guaranteed. As a method for solving this, Patent Document 1 describes a technique for identifying a charger by providing an identification circuit in a battery pack.

Japanese Patent Laid-Open No. 5-135804

  In addition, research and development related to the enhancement of functionality of portable electronic devices has been vigorously advanced, and power consumption has been increasing in proportion to the enhancement of functionality. In addition, these portable electronic devices are required to be driven for a long time, and in order to drive the electronic devices for a long time, it is necessary to increase the capacity of the drive power supply. However, in the case of portable electronic devices, there is a limit to increasing the capacity by increasing the size of the battery pack from the viewpoint of the occupied volume, weight, etc. of the built-in battery. Densification has been desired.

  The higher the energy density of the battery, the better. Currently, since the lithium ion battery has an excellent energy density, the lithium ion battery is built in various electronic devices. Currently, lithium ion batteries that operate at a maximum of 4.2 V only use about 60% of the theoretical capacity, and do not effectively use performance. As a method for solving this problem, Patent Document 2 discloses a technique for realizing a high energy density by sufficiently increasing the charging voltage to 4.25 V or more and performing sufficient charging in a short time.

JP-A-6-325794

  However, using a battery pack provided with an identification circuit described in Patent Document 1 is uneconomical because it is necessary to use a charger that is suitable for each battery pack.

  Furthermore, in order to perform the charging described in Patent Document 2, a high-charge voltage dedicated charger that can be charged with a charging voltage of 4.2 V or higher is required. If a secondary battery with a charging voltage of 4.2 V or less is accidentally charged with this high-charge voltage dedicated charger, there is a risk of heat generation or ignition.

  Accordingly, an object of the present invention is to allow a battery charger to read battery information stored in a non-volatile memory mounted on a battery pack, automatically determine a charging voltage suitable for the battery pack, and supply the battery pack to the battery pack. An object of the present invention is to provide a battery pack and a charger that can be charged correctly by converting a charging voltage to be used.

  In order to solve the above-described problem, according to a first aspect of the present invention, in a battery pack having a secondary battery and a circuit for controlling charging / discharging of the secondary battery, battery information defining a charging voltage value is stored. A non-volatile storage unit, and a communication unit that transmits the battery information to the charger by wireless communication, and charging by transmitting a charging voltage value to the charger via the communication unit. The battery pack is configured to be charged with a charging voltage set in the container.

  Further, according to a second aspect of the present invention, in a charger for charging a battery pack, the battery information from the battery pack is obtained by wireless communication with a nonvolatile storage unit in which battery information of the rechargeable battery pack is stored. It has a communication unit for receiving, a determination unit for determining whether charging is possible based on the received battery information, and a transformer circuit that converts the supplied voltage into a charging voltage suitable for the connected battery pack. It is a charger.

  The present invention automatically determines the charging voltage of the battery pack based on the battery information stored in the non-volatile memory of the battery pack. It becomes possible to charge at a suitable voltage.

  Further, in the present invention, since battery information is transmitted and received between the battery pack and the charger using wireless communication, the number of terminals that the battery pack and the charger are in contact with each other can be reduced, and the interface is simplified. Is possible.

  Embodiments of the present invention will be described below with reference to the drawings. First, an example of a battery pack using a secondary battery, for example, a lithium ion battery will be schematically described with reference to FIG. The battery pack 40 is attached to the charger 50 at the time of charging, and charging is performed by connecting the + terminal 1 and the −terminal 2 to the + terminal 20 and the −terminal 21 of the charger 50, respectively. When the electronic device is used, the + terminal 1 and the − terminal 2 are connected to the + terminal and − terminal of the electronic device and discharged.

  The battery pack 40 mainly includes a battery cell 5, an IC (Integrated Circuit) chip 6, an antenna 3, and a switch circuit 4. The battery cell 5 is, for example, a lithium ion battery in which a plurality of battery cells are connected in series.

  The IC chip 6 includes a CPU (Central Processing Unit) 9 and a nonvolatile memory EEPROM (Electrically Erasable and Programmable Read Only Memory) 10. The CPU 9 has a measurement function, and calculates the remaining capacity of the battery based on the voltage value of the battery cell 5. Moreover, in the temperature detection part 7, battery temperature is monitored by temperature detection elements, such as a thermistor. The calculated remaining capacity data and battery temperature data are stored in the EEPROM 10. Further, the CPU 9 has a protection function, and when the voltage of the battery cell 5 becomes an overcharge detection voltage or an overdischarge detection voltage, an overcharge control signal or an overdischarge control signal is sent to the switch circuit 4 to thereby Prevent charging and over-discharging.

  In addition to the data described above, the EEPROM 10 stores battery information such as the IC chip and battery pack manufacturer and model, and is used to determine whether or not the battery pack can be used during charging. FIG. 2 shows an example of stored battery information. The stored battery information is classified into three categories, for example, IC chip, battery manufacture, and battery use. Also, access rights are set for each battery information, and access is restricted. When accessing battery information, for example, a password is used, and access is possible only when authentication by the password is successful.

  The battery information classified into the IC chip category is data on the IC chip manufacturer, model, date of manufacture, and manufacturing location / lot. These data are stored in the EEPROM 10 by the IC chip manufacturer when the IC chip is manufactured. Data regarding manufacturer, model and date of manufacture is accessible to IC chip manufacturers and battery manufacturers. Also, only the IC chip manufacturer can access data relating to the manufacturing location / lot.

  The battery information classified into the battery manufacturing category is data regarding the manufacturer, model, date of manufacture, and manufacturing location / lot of the battery pack. These data are stored in the EEPROM 10 by the battery pack manufacturer when the battery pack is manufactured. Data regarding the manufacturer, model, and date of manufacture is accessible to battery manufacturers, chargers and battery powered equipment. Further, only the battery manufacturer can access the data relating to the manufacturing location / lot.

  The battery information classified into the battery use category is data on the number of times of charge, remaining capacity, and temperature. These data are stored in the EEPROM 10 by the battery pack manufacturer when the battery pack is manufactured. Data that falls into this category is accessible to battery manufacturers, chargers and battery-powered equipment. The number-of-charges data indicates the number of times the battery has been charged in the past. After the completion of charging, the number-of-charges data obtained by adding the number of times to the data is written in the EEPROM 10.

  The remaining capacity data indicates the remaining capacity of the battery, is calculated when the battery pack 40 is connected to the charger 50 or the electronic device, and is written in the EEPROM 10. Further, during charging or using the electronic device, the remaining capacity data is calculated and written to the EEPROM 10 at predetermined time intervals such as once every several seconds. The remaining capacity data is read in response to a request from the charger 50 or the electronic device, and the remaining capacity of the battery based on the remaining capacity data is displayed on a display unit such as a liquid crystal of the charger 50 or the electronic device.

  The temperature data indicates the temperature of the battery, is calculated every time the battery pack 40 is connected to the charger 50 or the electronic device, and is written in the EEPROM 10. Further, during charging or use of the electronic device, the temperature data is calculated at predetermined time intervals such as once every several seconds and written in the EEPROM 10.

  The battery information stored in the EEPROM 10 is not limited to this example. For example, data on materials used in the battery pack 40 may be further stored.

  Returning to FIG. 1, the battery information stored in the EEPROM 10 is read based on a request from the charger 50 or the electronic device and sent to the communication unit 8. The communication unit 8 transmits battery information to the charger 50 and the electronic device via the antenna 3.

  The switch circuit 4 is for controlling a charging current and a discharging current, and includes, for example, a charging control FET (Field Effect Transistor) 4a and a discharging control FET 4b. When the battery voltage becomes an overcharge detection voltage, the charge control FET 4a is turned off by the overcharge control signal received from the CPU 9, and the charging current is controlled not to flow. After the charge control FET 4a is turned off, only discharging is possible through a diode.

  Further, when the battery voltage becomes equal to or lower than the overdischarge detection voltage, the discharge control FET 4b is turned off by the overdischarge control signal received from the CPU 9, and the discharge current is controlled not to flow. After the discharge control FET 4b is turned off, only charging is possible through a diode.

  Next, an example of the charger 50 will be described. When the battery pack 40 is attached to the charger 50, the + terminal 20 and the − terminal 21 of the charger 50 are connected to the + terminal 1 and the − terminal 2 of the battery pack 40, respectively. The charger 50 mainly includes a charging circuit 26, a CPU 23, an EEPROM 24, a transformer circuit 25, and a communication unit 27.

  The charging circuit 26 is supplied with, for example, a commercial AC voltage from the outside through the input terminal 30 and the input terminal 31, and converts the AC voltage into a DC voltage. The converted DC voltage is supplied to the transformer circuit 25. The antenna 22 receives battery information transmitted from the battery pack 40 side, and the received battery information is sent to the CPU 23 via the communication unit 27. Based on the received battery information, the CPU 23 determines whether the battery pack 40 can be charged with an appropriate charging voltage. As the antenna 22 and the communication unit 27, near field communication means such as a wireless tag can be used.

  The EEPROM 24 stores battery information related to the battery pack that can be charged in advance, for example, battery information related to the manufacturer and type of the battery that can be charged, the effective period of the battery pack, the model, and the charging voltage associated with the model. . This battery information is used in the determination, and when the battery pack 40 can be charged, the CPU 23 sends a command to output a predetermined voltage to the transformer circuit 25.

  The transformer circuit 25 includes, for example, a transformer unit 28 formed of a DC / DC converter or a regulator, and a control unit 29 that controls an output voltage. The control unit 29 receives a command from the CPU 23, and receives the command. Based on this, the voltage of the transformer 28 is controlled. The transformer 28 steps up or down the voltage supplied from the charging circuit 26 according to a command from the control unit 29 and converts it into a charging voltage suitable for the battery pack 40. When charging is not possible, the charging voltage is not supplied to the battery pack 40, and a message indicating that charging is not possible is displayed on a display unit such as a liquid crystal provided in the charger 50.

  Here, the voltage supplied to the charging circuit 26 has been described as an AC voltage, but this is not limited to this example. The supplied voltage may be a DC voltage.

  FIG. 3 is a flowchart illustrating the flow when charging the battery pack 40. In step S <b> 1, the battery pack 40 is attached to the charger 50. The charger 50 detects that the battery pack 40 is attached by a sensor or the like (not shown). In step S <b> 2, the charger 50 receives battery information stored in the EEPROM 10 in the battery pack 40 by wireless communication and reads it into the memory in the CPU 23.

  In step S3, the data relating to the manufacturer and battery type included in the received battery information is collated with the data relating to the manufacturer and battery type that can be charged and stored in the EEPROM 24 in the charger 50, and charging is possible. It is determined whether or not there is. If it is a rechargeable battery manufacturer and battery type, the process proceeds to the next process. If it cannot be used, the process ends and charging is not performed.

  In step S4, it is determined whether or not the battery pack has exceeded the valid period based on the data regarding the date of manufacture contained in the received battery information, the valid period data stored in the EEPROM 24, and the current date. To do. If it is within the valid period, the process proceeds to the next process. When the valid period is exceeded, it is determined that charging is not possible, and charging is not performed.

  In step S <b> 5, it is determined whether or not the number of times of charging exceeds the number of times of charging based on the number of times of charging data included in the received battery information and the number of times of charging stored in the EEPROM 24. When the number of times of charging is within the allowable number of times of charging, the process proceeds to the next process. If the number of times of charging exceeds the number of times that can be charged, the process ends and charging is not performed.

  In step S6, the model data included in the received battery information is compared with the chargeable model data stored in the EEPROM 24 to determine whether or not the battery pack 40 can be charged. When the battery pack 40 can be charged, the process proceeds to the next process. If charging is not possible, the process ends and charging is not performed.

  In step S <b> 7, the charging voltage of the battery pack 40 is determined based on the model data, and the voltage supplied from the charging circuit 26 is converted into a charging voltage suitable for the battery pack 40 in the transformer circuit 25. In step S8, the battery pack 40 is charged.

  In step S <b> 9, when the charging of the battery pack 40 is completed, the charging number data obtained by adding the number of times is transmitted to the battery pack 40 and written in the EEPROM 10.

  In addition, about the process from step S3 to step S6, the order is not restricted to what was mentioned above. Moreover, you may perform the process from step S3 to step S6 in parallel. In the case of parallel processing, in the processing from step S3 to step S6, the battery pack 40 is charged only when it is determined that all can be charged, and when it is determined that even one cannot be charged, processing is performed. Is terminated and charging is not performed. When charging is not possible, a message indicating that charging is not possible is displayed on a display unit such as a liquid crystal of the charger 50.

  Further, in step S2, the charger 50 may receive all the battery information at once, and only the data used when executing each step from step S3 to step S6 is included in the battery information. You may make it receive each time.

  FIG. 4 shows a processing sequence when charging is performed. First, the CPU 23 in the charger 50 requests the CPU 9 in the battery pack 40 to transmit battery information. In response to this request, the CPU 9 reads out battery information stored in the EEPROM 10 and transmits it to the CPU 23 (step S2). The CPU 23 performs a discrimination process from step S3 to step S6 based on the received battery information. When it is determined that the battery pack 40 can be charged, the CPU 23 transmits a command for converting the voltage to the control unit 29 of the transformer circuit (step S7). The control unit 29 controls the transformer unit 28 based on the received command, and the battery pack 40 is charged with an appropriate charging voltage (step S8). When the charging is completed, the CPU 23 adds +1 to the charge count data in the EEPROM 10 (step S9).

  Next, a method for confirming the remaining capacity of the battery pack 40 will be described with reference to the flowchart of FIG. In step S11, the battery pack 40 is attached to the charger 50 or the electronic device. The charger 50 detects that the battery pack 40 is attached by a sensor or the like (not shown). The CPU 9 in the battery pack 40 calculates the remaining capacity based on the voltage of the battery cell 5 and writes the remaining capacity data in the EEPROM 10. In step S12, the charger 50 receives the remaining capacity data stored in the EEPROM 10 by wireless communication.

  In step S13, the remaining capacity of the battery pack is displayed on the charger 50 or a display unit such as a liquid crystal of the electronic device. In addition, while the battery pack 40 is being charged or the electronic device is being used, the remaining capacity is calculated every predetermined time by the CPU 9, and the remaining capacity data is transmitted to the charger 50 or the electronic device again. Based on this, the remaining capacity is displayed.

  FIG. 6 is a schematic diagram showing a processing sequence for checking the remaining capacity of the battery. First, when the battery pack 40 is attached to the charger 50 or the electronic device, the CPU 9 of the battery pack 40 calculates the remaining capacity of the battery. The CPU 23 of the charger 50 requests the CPU 9 to transmit remaining capacity data. In response to this request, the CPU 9 transmits the remaining capacity data stored in the EEPROM 10 (step S12). Based on the received remaining capacity data, the CPU 23 displays the remaining capacity of the battery on the charger 50 or the display unit of the electronic device (step S13). In addition, the remaining capacity is calculated every predetermined time, and the remaining capacity data is transmitted again to the charger 50 or the electronic device, and the remaining capacity is displayed based on the remaining capacity data.

  Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications based on the technical idea of the present invention are possible. For example, the present invention can be applied not only to a battery pack using a lithium ion battery but also to a battery pack using a nickel cadmium battery or a nickel metal hydride battery.

  Further, in the wireless communication between the battery pack 40 and the charger 50, the data to be transmitted / received may be encrypted. In that case, it is necessary to add encryption and decryption circuits to the battery pack 40 and the charger 50.

It is a block diagram which shows the circuit structure of the battery pack 40 and the charger 50 in one Embodiment of this invention. 3 is a schematic diagram illustrating an example of battery information stored in an EEPROM 14. FIG. It is a flowchart explaining the flow of charge in one Embodiment of this invention. It is a basic diagram which shows the process sequence in the case of performing charge in one Embodiment of this invention. It is a flowchart which shows the flow which confirms the remaining capacity of the battery in one Embodiment of this invention. It is a basic diagram which shows the process sequence in the case of confirming the remaining capacity of the battery in one Embodiment of this invention.

Explanation of symbols

3 Antenna 4 Switch Circuit 5 Battery Cell 6 IC Chip 9 CPU
10 EEPROM
22 Antenna 23 CPU
24 EEPROM
25 Transformer circuit 26 Charging circuit 40 Battery pack 50 Charger

Claims (6)

In a battery pack having a secondary battery and a circuit for controlling charge / discharge of the secondary battery,
A non-volatile storage unit that stores battery information that defines a charging voltage value;
A communication unit that transmits the battery information to the charger by wireless communication;
A battery pack configured to be charged with a charging voltage set in the charger by transmitting the charging voltage value to the charger via the communication unit. The battery pack according to claim 1,
The battery information above is
A battery pack having a charging voltage value of the battery pack. The battery pack according to claim 1,
The battery information above is
A battery pack characterized by being one of a manufacturer and a battery pack type. The battery pack according to claim 1,
The battery information above is
A battery pack, characterized in that it is the date of manufacture of the battery pack. The battery pack according to claim 1,
The battery information above is
A battery pack, wherein the battery pack is one of a manufacturing place and a manufacturing lot. In the charger that charges the battery pack,
A non-volatile storage unit storing battery information of a rechargeable battery pack;
A communication unit that receives battery information from the battery pack by wireless communication;
A determination unit for determining whether charging is possible based on the received battery information;
And a transformer circuit for converting the supplied voltage into a charging voltage suitable for a connected battery pack.

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