JPH0613111A - Battery pack - Google Patents

Abstract

PURPOSE:To provide a battery pack in which optimum charging conditions for a secondary battery and the information of discharge ending voltage and others are incorporated to prevent treatment error in charge and discharge and to achieve the long life of the secondary battery. CONSTITUTION:A battery pack is provided with a secondary battery 1 and a non-volatile semiconductor memory 3. It has a terminal 2 to input/output a current to the secondary battery 1 and a terminal 4 to input/output information of the secondary battery to the non-volatile semiconductor memory 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack for small electronic equipment.

[0002]

2. Description of the Related Art In recent years, the production of small portable devices typified by camera-type video and specific low-power radios has increased remarkably, and the demand for secondary batteries as a power source for small portable devices has increased rapidly. Is growing. Especially for camera-type video, a battery pack that houses several nickel-cadmium batteries in one case and has a current input / output terminal is predominant. The battery pack is easy to remove and robust, making it very easy to handle. In addition, the NiCad battery is resistant to overcharging and overdischarging, and can be rapidly charged by using a dedicated charger, so it can be said that it is very suitable as a power source for small portable devices.

However, since the nicad battery has a small capacity per weight, if a large capacity is required, a heavy battery must be equipped. In addition, the nickel-cadmium battery has a weak point that it has a large self-discharge and its storage stability after charging is poor. For this reason, battery packs having a remaining amount display function in the battery pack itself are also commercially available. Also, cadmium used as an electrode is a pollutant and should be handled with care.

Recently, high capacity nickel hydrogen batteries have begun to be mass-produced. It has about the same voltage as a NiCad battery and can be used as a replacement for a NiCad battery. The capacity per volume is 1.5 times that of a NiCd battery, and if the battery is the same size, the device can be used for 1.5 times the time. In addition, since it does not contain pollutant,
It is said to be the main battery for mobile devices. As a secondary battery having a higher capacity, there is a lithium secondary battery. This is the voltage of a single battery is 3 ~ 3.6V and 2 of NiCad battery.
It is a high-performance secondary battery that is more than double the high voltage, lightweight, and has less self-discharge.

Since these high-performance secondary batteries are inferior to nickel-cadmium batteries in the magnitude of charging / discharging current and the strength against overcharging / overdischarging, it is not a rush to completely replace the nickel-cadmium batteries. There is also a problem that the cost is high. However, it is clear that in the near future, a battery pack using these high performance secondary batteries will be used.

Now, considering a device using a battery pack, at present, all are designed with a nickel cadmium battery in mind. Therefore, even if a high performance battery comes out, it cannot be used so easily. Particularly problematic is the charger. If the battery is charged in the same manner as the Ni-Cd battery, the charging current may be too large or the charging end point may be incorrect, resulting in a significant reduction in the battery life.

Further, the portable device side usually has a low battery capacity warning function. This is often intended to work when the battery voltage drops below a certain voltage. However, since this is also optimized for NiCd batteries, it may cause over-discharge for other types of batteries. Conventionally, there has not been a battery pack capable of solving such a problem related to charging / discharging and being removable from a device.

[0008]

DISCLOSURE OF THE INVENTION The present invention incorporates information such as the optimum charging conditions and discharge end voltage of a secondary battery to prevent erroneous processing related to charging / discharging and to prolong the life of the secondary battery. It is an object of the present invention to provide a battery pack that has achieved high efficiency.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is a battery pack comprising a secondary battery and a non-volatile semiconductor memory, wherein a terminal for inputting and outputting a current to and from the secondary battery is provided. A non-volatile semiconductor memory is provided with a terminal for inputting / outputting information about the secondary battery, which is achieved by a battery pack.

FIG. 1 shows a configuration example of the present invention. Reference numeral 1 denotes a secondary battery that can store electric energy, and is generally configured by connecting a plurality of secondary batteries of the same type and the same capacity in series. Metal plates made of nickel or stainless are spot-welded to the positive and negative electrodes of the battery, and the batteries are connected in series through the metal plate 6, and at the same time, the current extraction terminal 2 is formed. The semiconductor memory 3 is arranged on the double-sided printed circuit board 5, and the information input / output terminal 4 is constituted by the conductor pattern on the back surface side. These are enclosed in a robust case 7 to form the battery pack according to the present invention. The charger and the load device use the current output terminal 2 to input and output electrical energy.
Through the information input / output terminal 4.

A feature of the present invention is that the battery pack has a nonvolatile semiconductor memory and an information input / output terminal built therein. By storing various information regarding charging / discharging in this non-volatile memory through the information input / output terminal and utilizing the information in the portable device or the charger, the problem regarding charging / discharging of the secondary battery can be solved.

The information to be stored includes the following.

(1) Battery type (2) Charge / discharge count (З) Optimum charge current (4) Charge end voltage (5) Discharge end voltage (6) Charge end date and time (7) Battery usage time Use these information This makes using the battery pack extremely convenient.

For example, if the type of battery is known, the charger can be given a function of controlling itself and selecting a charging method suitable for the battery. If the optimum charging current and the end-of-charge voltage are known, even if the secondary battery is an unknown high-performance battery, by controlling the charger,
You can safely charge the battery pack. Further, if the number of times of charging / discharging (history) is known, it is possible to display a warning that the battery pack has reached the end of its life. Furthermore, the remaining battery level can be known from the date and time when the battery was last charged and the time when the battery was used.

By thus incorporating the non-volatile memory in the battery pack, the battery can be used more highly and conveniently. Needless to say, the use of these does not burden the user. By combining a battery charger and a battery charger that can read and write information in the nonvolatile memory built into the battery, it is possible to perform the fine control described above.

The secondary battery used in the present invention includes a small sealed lead battery, a nickel-cadmium battery, a nickel-hydrogen battery,
There are lithium secondary batteries and the like. For lithium secondary batteries, the main method has not been decided yet, there are variations such as those using vanadium oxide for the positive electrode material, those using organic polymer, and lithium metal was also used for the negative electrode material. There are those using an alloy of lithium and aluminum, one using a carbon material doped with a large amount of lithium ions, and the like.

The nonvolatile memory usable in the present invention includes a read-only ROM, an electrically erasable / writable EEPROM or NVRAM, and a battery-packed SRAM. Of these, the most suitable for the present invention is an EEPROM that can be electrically written / erased with a single power source and does not require a backup battery. The EEPROM has a smaller number of writable times than the SRAM and the DRAM, and the speed thereof is generally slow, but it has sufficient performance for the application where high speed is not required as in the present invention. If you increase the memory capacity, the amount of information that can be stored will increase, and of course, you can finely control the charging and discharging operations, but on the other hand, you must increase the number of information input / output terminals and the cost of memory devices will increase, so the system It is necessary to make the capacity commensurate with. Also, if it is exclusively for reading, it may be configured by hardware logic such as a flip-flop.

The information input / output terminals used in the present invention are
It consists of terminals for inputting and outputting memory data, terminals for specifying memory addresses, terminals for controlling reading and writing to the memory, and terminals for supplying power to the memory. Of these, the terminal that supplies power is
The current input / output terminal of the secondary battery may also be used. If a read-only ROM is used, the terminals for controlling reading and writing can be omitted. Also, if the amount of information is small, the terminal for specifying the memory address can be omitted.

The shape of the terminal is preferably configured so that there is no protrusion. If there are protrusions, it is easy to damage your hands or damage the terminals during handling of the battery pack. As the terminal material, the material used in the existing connector is sufficient. Usually, gold-plated metal or nickel, which has a low contact resistance, is used.

The current input / output terminals used in the present invention also include
Similar to the above information input / output terminal, it is required to be as flat as possible and have low contact resistance. It should be noted that the contact resistance is particularly small because the current input / output terminal must withstand a relatively large current. For this reason, it is usually larger in size than the information input / output terminal.

[0021]

EXAMPLES The present invention will be specifically described below based on examples.

(Embodiment 1) A 256K (32K × 8) bit OTPROM (a PROM that can be electrically written only once at the beginning, Fujitsu's MBM27256P) is used as a nonvolatile semiconductor memory and is soldered on a double-sided printed circuit board. After fixing, the back side of the fixing surface was used as an input / output terminal. As batteries, four nickel-cadmium batteries were connected in series with nickel plates, and at the same time used as current input / output terminals. These were housed in a urethane case to form a battery pack according to the present invention.

A circuit diagram is shown in FIG. In the present invention,
The address terminal and the read / write control terminal are not used, and the information at a fixed address is always readable. The data width is 2 bits, and the power supply line is shared with the current input / output terminal. With this configuration, the number of information input / output terminals is as small as two, which is very simple. 4 using this memory
You can write the type of battery. For example,
If the code number is decided in advance, such as 0 for NiCd battery, 1 for Lithium secondary battery, 2 for Nickel metal hydride battery, 3 for lead battery, adjust the charging current etc. on the charger side for each. You can Needless to say, the battery type must be written in R0M before the battery pack is manufactured.

(Embodiment 2) A 64K (8Kx8) bit EEPROM (Fujitsu MBM28C64, 5V single power supply type) is used as a non-volatile semiconductor memory.
This was fixed on a double-sided printed circuit board with solder, and the back side of the fixed surface was used as an input / output terminal. As the battery, NiCd battery 4
The pieces were connected in series with a nickel plate, and this nickel plate was simultaneously used as a current input / output terminal. These were housed in a urethane case to form a battery pack according to the present invention.

A circuit diagram is shown in FIG. In the present invention,
The address terminal has 2 bits, the data width has 8 bits, and the power supply line is shared with the current input / output terminal. Three control terminals are provided for reading and writing. In this configuration, the number of information input / output terminals is 13. Many types of batteries can be written using this memory. For example, if the code number is decided beforehand such as 0 for NiCd battery, 1 for Lithium secondary battery, 2 for Nickel hydrogen battery and 3 for lead battery, the charging current etc. for each is adjusted on the charger side. You can do it. Needless to say, the battery type must be written in the EEPROM before manufacturing the battery pack.

Further, in this embodiment, since reading and writing can be performed while the battery is in use, the number of times of charging and discharging can be recorded to manage the life of the battery. Since the number of times the battery is charged and discharged is at most 1,000, 16
The amount of information in bits (0 to 65535) is sufficient. In this embodiment, since 8-bit data can be stored for 4 addresses,
Two addresses can be used for charge / discharge times, one address can be used for battery type information, and the last one address can be used for management of charging current and the like.

(Embodiment 3) A 64K (8Kx8) bit EEPROM (Fujitsu MBM28C64, 5V single power supply type) is used as a non-volatile semiconductor memory.
This was fixed on a double-sided printed circuit board with solder, and the back side of the fixed surface was used as an input / output terminal. As a battery, NiCd battery 6
The pieces were connected in series with a nickel plate and used as current input / output terminals at the same time. If a lithium secondary battery with a voltage of 3.6V is used, the same output voltage can be secured with only two batteries. These were housed in a urethane case to form a battery pack according to the present invention.

A circuit diagram is shown in FIG. In this embodiment, the address terminal is 6 bits, and the data width is
It has 8 bits, and the power line is not shared with the battery and two lines are output independently. Since the power supply is separate from the battery, the electricity of the battery is not used, and the voltage of the battery can be selected independently of the operating voltage of the memory. Three control terminals are provided for reading and writing. In this configuration, the number of information input / output terminals is 19. Many types of batteries can be written using this memory. For example, if the code number is decided in advance, such as 0 for nickel-cadmium battery, 1 for lithium secondary battery, 2 for nickel-hydrogen battery, 3 for lead-acid battery, the charging current for each is adjusted on the charger side. You can do it. Needless to say, the battery type is EEP before manufacturing the battery pack.
Must be written in ROM. Further, in this embodiment, since 8-bit data can be used for 64 addresses as a readable / writable data amount while the battery is used,
Fine control is possible. An example of use as a remaining amount management function is shown below.

As the necessary information, the self-discharge rate L per hour and the battery capacity C are previously written in the memory as initial information. After that, the remaining amount management operation is performed according to the following steps.

(Step 1) The battery is charged by the charger, and the date and time d0 when the charging is completed, the date and time dl (= d0) at the end of use, and the use time u (= 0) are written from the charger to different positions in the memory. The values in parentheses are initial values.

(Step 2) Set the battery pack in the load device.

(Step 3) When the load device starts to use the battery, the remaining amount Z of the battery is calculated by the following equation.

Z = C (1-L (dl-d2))-Iu where d2 is the start date and time of use and I is the current consumption of the load device (step 4). If Z≤0, the remaining amount of the load device is 0. Is displayed and it is recommended to charge the battery. Charge the battery and return to step 1.

(Step 5) When Z> 0, Z is displayed and the current date and time is used while the device is in use.
Continue writing to l. At the same time, the remaining amount Z is decreased with time, and the usage time u is continuously increased. In this way, when the use ends, the use time and the use end date and time are automatically updated. If Z ≦ 0 during use, the remaining amount O is displayed, the battery is recommended to be charged, the battery is charged, and the process returns to step 1.

(Step 7) Stop the load device and remove the battery pack. When reusing, return to step 2.

As described above, it is possible to manage the remaining battery level for the first time. Since this method also considers self-discharge, it has the feature that the remaining amount can be managed even with the battery pack left unattended.

[0037]

According to the present invention, that is, a battery pack including a secondary battery and a non-volatile semiconductor memory, wherein the non-volatile semiconductor memory has a terminal for inputting and outputting a current to and from the non-volatile semiconductor memory. With the battery pack provided with terminals for inputting / outputting information related to the next battery, (1) the remaining amount of each battery pack can be managed.

(2) The history (lifetime) of each battery pack can be managed.

(3) It is possible to control the end-of-charge voltage and the charging current depending on the type of battery, and the charger and the load device can handle unknown batteries.

As described above, the battery pack according to the present invention is a so-called human-friendly battery that can be highly controlled, does not require manual handling, and has a high industrial utility value.

[0041]

[Brief description of drawings]

FIG. 1 is an external view of a battery pack according to the present invention.

FIG. 2 is a circuit diagram of a first embodiment of the present invention.

FIG. 3 is a circuit diagram of a second embodiment of the present invention.

FIG. 4 is a circuit diagram of a third embodiment of the present invention.

FIG. 5 is an external view of a conventional battery pack.

[Explanation of symbols]

 1 rechargeable battery, 2 current input / output terminal, 3 semiconductor memory, 4 information input / output terminal, 5 printed circuit board, 6 metal plate for series connection, 7 case, 8 screw, 9 groove for mounting to device.

Claims (1)

[Claims] 1. A battery pack comprising a secondary battery and a non-volatile semiconductor memory, wherein terminals for inputting and outputting a current to and from the rechargeable battery and the non-volatile semiconductor memory are related to the rechargeable battery. A battery pack having a terminal for inputting and outputting.