JP7613034B2 - Charging device, electronic device, charging method, and computer program - Google Patents

Description

The present invention relates to a charging device, an electronic device, a charging method, and a computer program.

In lithium-ion batteries, which are widely used as secondary batteries, when they are charged at low temperatures, lithium metal in the electrolyte precipitates, causing deterioration such as an increase in internal resistance, a sudden decrease in capacity, and a decrease in quality due to an electrical short circuit within the battery. For this reason, a lower limit charging temperature has been set below which these problems do not occur, and charging is stopped when the temperature falls below this lower limit.

Here, the temperature of the secondary battery may fluctuate slightly but frequently around the lower limit temperature. The temperature sensor may pick up noise, causing the temperature indicated by the output signal to fluctuate around the lower limit temperature. In such cases, charging may start or resume and stop frequently, which may reduce the reliability of electronic circuits such as switching ICs (Integrated Circuits) and relays that start and stop charging.

To address this issue, Patent Document 1 discloses a technique for controlling the charging state according to the temperature of the secondary battery by setting a first threshold temperature at which the charging stop is released and a second threshold temperature at which the charging state is changed to a charging stop state.

JP 2019-80406 A

In the technology disclosed in Patent Document 1, when the temperature of the secondary battery is stable between the first threshold temperature and the second threshold temperature, or when it takes a long time for the temperature of the secondary battery to rise from the second threshold temperature to the first threshold temperature, a state occurs in which the secondary battery is not charged even though its temperature is higher than the first threshold temperature. In this way, the technology disclosed in Patent Document 1 has problems such as low charging time efficiency, long charging time, and in some cases insufficient remaining capacity.

Similar problems exist, although to varying degrees, for secondary batteries other than lithium-ion batteries.

The present invention has been made to solve the above-mentioned problems, and its purpose is to improve the time efficiency of charging a secondary battery while suppressing deterioration of electronic circuits.

In order to achieve the above object, a charging device according to a first aspect of the present invention comprises:
A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit is
the charging circuit permits charging of the secondary battery when a temperature related to the secondary battery is less than a first threshold temperature and a first condition related to the temperature of the secondary battery is satisfied;
when the temperature related to the secondary battery is less than the first threshold temperature and the first condition is not satisfied, charging of the secondary battery is not permitted;
a charging circuit that: i) permits charging of the secondary battery when a temperature related to the secondary battery is equal to or higher than the first threshold temperature; and ii) stops charging of the secondary battery when the temperature related to the secondary battery falls below a second threshold temperature that is lower than the first threshold temperature;
The first condition is that the calculated time to reach the second threshold temperature is less than a certain time.
In order to achieve the above object, a charging device according to a second aspect of the present invention comprises:
A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit is
the charging circuit permits charging of the secondary battery when a temperature related to the secondary battery is less than a first threshold temperature and a first condition related to the temperature of the secondary battery is satisfied;
when the temperature related to the secondary battery is less than the first threshold temperature and the first condition is not satisfied, charging of the secondary battery is not permitted;
a charging circuit that: i) permits charging of the secondary battery when a temperature related to the secondary battery is equal to or higher than the first threshold temperature; and ii) stops charging of the secondary battery when the temperature related to the secondary battery falls below a second threshold temperature that is lower than the first threshold temperature;
When the temperature of the secondary battery is below the second threshold temperature, a fixed time is waited, and after waiting for the fixed time, charging is allowed if any of the following conditions is met: the temperature of the secondary battery is on an increasing trend, the rate of temperature increase is higher than a certain rate of increase, the slope of the temperature change is on an increasing trend, and the calculated time to reach the second threshold temperature is shorter than a certain time.
In order to achieve the above object, a charging device according to a third aspect of the present invention comprises:
A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit controls the charging circuit,
When the temperature of the secondary battery is equal to or higher than a first threshold temperature, charging of the secondary battery is permitted;
permitting charging when the temperature of the secondary battery is less than a second threshold temperature that is lower than the first threshold temperature and a second condition regarding the temperature of the secondary battery is satisfied;
When the temperature of the secondary battery is less than the second threshold temperature and the second condition is not satisfied, charging is stopped;
The second condition is one of the following: the temperature of the secondary battery is on an increasing trend; the rate of temperature increase is higher than a certain rate of increase; the slope of the temperature change is on an increasing trend; and the calculated time to reach the second threshold temperature is shorter than a certain time.

The above configuration makes it possible to improve the time efficiency of charging the secondary battery while suppressing deterioration of the electronic circuit.

1 is a block diagram of an electronic device according to an embodiment of the present invention. FIG. 2 is a block diagram of a charging control unit according to an embodiment of the present invention. 4 is a flowchart showing a charging control process according to the first embodiment of the present invention. 4 is a diagram showing the relationship between temperature change and charging of the rechargeable battery according to the first embodiment of the present invention. FIG. 10 is a flowchart showing a charging control process according to a second embodiment of the present invention. 10 is a flowchart showing a modified example of the charge control process according to the second embodiment of the present invention. 10 is a flowchart showing a charging control process according to a third embodiment of the present invention.

The following describes a charging device, electronic device, charging method, and computer program according to an embodiment of the present invention with reference to the drawings. Note that in each drawing, the same components are given the same reference numerals.

(Embodiment 1)
The electronic device of the present embodiment is a device that includes a secondary battery, operates while consuming power stored in the secondary battery, and realizes various functions. However, the various functions and configurations of the electronic device are optional. Therefore, the following description will focus on a charging device that charges the secondary battery, which is characteristic of the embodiment.

As shown in the block diagram of FIG. 1, an electronic device 1 according to this embodiment includes an input unit 3 that receives power from an AC (Alternating Current) adapter 2, a secondary battery 4, a temperature sensor 5 that detects the temperature of the secondary battery 4, and a charging device 6.
Since the method for measuring the temperature of the secondary battery 4 is arbitrary, in this embodiment, it is described as the temperature TB related to the secondary battery 4. The temperature TB related to the secondary battery 4 includes, for example, the temperature of an arbitrary portion of the secondary battery 4, the temperature of the electrodes of the secondary battery 4, the temperature of the surface of the secondary battery 4, the temperature at a position within the range where the heat of the secondary battery 4 is transmitted, and the like, and includes any of these temperatures measured by the temperature sensor 5.

The charging device 6 includes a charging circuit 61 that charges the secondary battery 4 when power is being supplied from the AC adapter 2 to the input unit 3, and stabilizes and outputs the output voltage of the secondary battery 4 when power is not being supplied from the AC adapter 2, and a charging control unit 62 that controls the charging circuit 61. The charging control unit 62 includes, for example, a microcomputer.

The AC adapter 2 is an external power source for the electronic device 1, and generates a DC power source voltage for the electronic device 1 from an AC power source. The AC adapter 2 has a connection plug that is detachably connected to the input unit 3, and supplies DC power to the electronic device 1 via the connection plug connected to the input unit 3. The external power source may be a DC power source.

The connection plug of the AC adapter 2 is removably attached to the input unit 3, and DC power is supplied from the AC adapter 2. The input unit 3 supplies the supplied DC power to each internal circuit (not shown) of the electronic device 1 as operating power, and further supplies it to the charging device 6.

The secondary battery 4 is a rechargeable battery, for example a lithium ion battery.

The temperature sensor 5 is equipped with a temperature detection element such as a thermistor or a thermocouple, and is installed in a position where it can measure the temperature TB related to the secondary battery 4.

The charging circuit 61 of the charging device 6 includes a reverse current prevention circuit, a conductive/non-conductive switch, etc., a charging circuit that applies the DC voltage supplied from the AC adapter 2 to the secondary battery 4, and a regulator that regulates the output voltage of the secondary battery 4, and charges the secondary battery 4 when a DC voltage is being supplied from the AC adapter 2 according to the control of the charging control unit 62, and stabilizes the output voltage of the secondary battery 4 and supplies it to the internal circuit when no power supply voltage is being supplied from the AC adapter 2. In addition, the charging circuit 61 outputs a power supply detection signal to the charging control unit 62 when a power supply voltage is being supplied from the AC adapter 2.

As shown in the block diagram of FIG. 2, the charging control unit 62 includes a processor 621, a RAM (Random Access Memory) 622, a ROM (Read Only Memory) 623, and an input/output interface (hereinafter, I/O) 624.

The processor 621 uses the RAM 622 as a work memory to execute a control program stored in the ROM 623, and executes the charging control process described below with reference to FIG. 3. The processor 621 also includes an internal timer.

RAM 622 functions as a work area for processor 621, storing running programs and various data.

ROM 623 stores the control program for the charging control process described later, fixed data used for the control, etc. The fixed data includes a first threshold temperature T1, a second threshold temperature T2, a reference time tr, etc. The second threshold temperature T2 is a temperature threshold for determining whether or not to stop charging during charging, and is basically a threshold temperature for determining that charging is to be stopped when the temperature TB related to the secondary battery 4 drops below the second threshold temperature T2 during charging. The second threshold temperature T2 is set to a limit temperature below which the secondary battery 4 is damaged, such as by deposition of metal ions in the electrolyte, if charging is performed at a temperature lower than that. In a lithium-ion battery, it is set to about 0°C. On the other hand, the first threshold temperature T1 is a temperature threshold for determining whether or not to start charging during non-charging. The first threshold temperature T1 is a set value of a temperature that is higher than the second threshold temperature T2 and is desirable to reach during charging, and is set to about 5°C in a lithium-ion battery. By setting it in this way, it is possible to provide hysteresis to the threshold temperature of the secondary battery 4 when deciding whether to start charging and when to stop charging.

The reference time tr is a set value for the maximum time for which the first threshold temperature T1 is continuously used, and is, for example, 5 seconds. As described below, the first threshold temperature T1 is used as the threshold temperature for determining whether charging can be started, and if it is determined that charging cannot be started for a period of time equal to or longer than the reference time tr, the threshold temperature is switched to the second threshold temperature T2 to determine whether charging can be started. In other words, the threshold temperature for determining whether charging can be started is switched.

The I/O 624 mediates communication between the processor 621 and an external circuit. For example, the I/O 624 receives a power detection signal supplied from the charging circuit 61 and temperature data indicating the temperature TB of the secondary battery 4 supplied from the temperature sensor 5 as a temperature information acquisition unit, and transmits them to the processor 621. The I/O 624 also supplies a charge control signal output by the processor 621 to the charging circuit 61.
The bus 625 transfers data between the processor 621 and the RAM 622, ROM 623, and I/O 624.

Next, the operation of the electronic device 1 having the above configuration will be described.
When the connection plug of the AC adapter 2 is not connected to the input unit 3 of the electronic device 1, or when it is connected but not supplying power, the charge/discharge circuit 61 regulates the output voltage of the secondary battery 4 and supplies it to each internal circuit. The internal circuits operate by consuming the supplied power, and realize various functions of the electronic device 1.

On the other hand, when the connection plug of the AC adapter 2 is connected to the input unit 3 of the electronic device 1 and power is being supplied, the power supplied from the AC adapter 2 is supplied to each internal circuit. Each internal circuit consumes the supplied power to operate and realize various functions of the electronic device 1.

When the charging circuit 61 detects the supply of power from the AC adapter 2, it outputs a power supply detection signal to the charging control unit 62.

The processor 621 of the charging control unit 62 receives a power supply detection signal via the I/O 624 and the bus 625. In response to the received power supply detection signal, the processor 621 executes a charging control program stored in the ROM 623, using the RAM 622 as a work memory.
The charging control process executed by the processor 621 to control the charging circuit 61 will be described below with reference to the flowchart of FIG.

When the processor 621 starts the charging control process, it first instructs the charging circuit 61 to stop charging via the I/O 624 (step S110). This is to avoid charging until it is confirmed that the secondary battery 4 is in a chargeable state. In response to the instruction, the charging circuit 61 stops the charging operation by opening the current switch of the charging circuit, for example, and enters a non-charging state.

Next, the processor 621 resets and restarts an internal timer to measure the period during which charging is stopped (elapsed time ts) (step S120).
Next, the processor 621 reads temperature data indicating the temperature TB of the secondary battery 4 from the temperature sensor 5 via the I/O 624, and records the data in the RAM 622 with a time stamp (step S130).

The processor 621 determines whether the temperature TB for the secondary battery 4 indicated by the temperature data is equal to or higher than a first threshold temperature T1 indicating a desired temperature during charging (step S141).

When the processor 621 determines that the temperature TB for the secondary battery 4 is equal to or higher than the first threshold temperature T1 (step S141: Yes), it instructs the charging circuit 61 to start charging via the I/O 624 (step S142). The charging circuit 61 starts charging the secondary battery 4 in accordance with the instruction. Note that even if the processor 621 instructs the charging circuit 61 to start charging, the charging circuit 61 may not actually start the charging operation due to factors such as the convenience of the processing of the charging circuit 61, the charging state of the secondary battery 4, and control of safety devices. Therefore, in one sense, instructing the charging circuit 61 to start charging is equivalent to allowing the start of charging. The same applies to the charging operations described below.

On the other hand, if it is determined that the temperature TB of the secondary battery 4 is less than the first threshold temperature T1 (step S141: No), the processor 621 determines whether the elapsed time ts measured by the internal timer is equal to or greater than the reference time tr (step S143). Initially, ts < tr, the result of step S143 is No, and the flow returns to step S130 and repeats the same operation. Thus, after the start of power supply from the AC adapter 2, if the temperature TB of the secondary battery 4 is lower than the first threshold temperature T1, the processor 621 repeats the processes of steps S141, S143, and S130, and the state in which charging of the secondary battery 4 is stopped is maintained.

If this state continues for the reference time tr, tr≦ts is established, step S143 returns Yes, and processing proceeds to step S150.

In step S150, the processor 621 reads temperature data from the temperature sensor 5 via the I/O 624.

Next, the processor 621 determines whether the temperature TB for the secondary battery 4 indicated by the temperature data is equal to or higher than the second threshold temperature T2 (step S161).

When the processor 621 determines that the temperature TB for the secondary battery 4 indicated by the temperature data is equal to or higher than the second threshold temperature T2 (step S161: Yes), it instructs the charging circuit 61 to charge via the I/O 624 (step S170). That is, it allows the start of charging. Here, the criterion for determining the temperature condition for whether or not to allow the start of charging is the second threshold temperature T2. Here, step S143 is an example of the first condition in the claims.

In response to the instruction, the charging circuit 61 charges the secondary battery 4 with power provided by the AC adapter 2 .
Thereafter, the process returns to step S150, and the above-mentioned processes are repeated, whereby the secondary battery 4 is charged.

However, if the temperature TB of the secondary battery 4 drops due to a drop in the ambient temperature or the like and becomes less than the second threshold temperature T2 (step S161: No), the process returns to step S110 and charging is stopped. This prevents charging from being performed when the temperature TB of the secondary battery 4 is less than the second threshold temperature T2, which could damage the secondary battery 4. This also causes the second threshold temperature T2 to function as a threshold temperature for determining whether or not to stop the charging operation.

If the secondary battery 4 becomes fully charged while the above-mentioned charging control process is being executed, the charging circuit 61 stops the charging operation and notifies the charging control unit 62 of the full charge. In response to the notification, the charging control unit 62 ends the charging control process and goes into a standby state.

After that, when the secondary battery 4 becomes chargeable and power is being supplied from the AC adapter 2, the charging circuit 61 outputs a power source detection signal to the charging control unit 62. In response to the power source detection signal, the charging control unit 62 resumes the charging control process from step S110.

Next, the above-described charging control process will be described with reference to a specific example.
Here, as shown in FIG. 4, an example will be described in which, after the AC adapter 2 starts supplying power to the electronic device 1, the temperature TB of the secondary battery 4 fluctuates between the first and second threshold temperatures T1 and T2 for a while, drops below the second threshold temperature T2 once, and then rises again.

Immediately after the supply of power from the AC adapter 2 begins, the processor 621 starts the charging control process. At this stage, T2<TB<T1, so the result of step S141 is No, and ts<tr, so the result of step S143 is No. Therefore, the processes of steps S141, S143, and S130 are repeated, and the state in which the secondary battery 4 is not being charged (non-charging state) continues.

When the non-charging state continues for the reference time tr, tr≦ts is established, and step S143 returns Yes. Therefore, processing proceeds to step S150. In FIG. 4, at this point, T2<TB, so step S161 returns Yes, and charging begins in step S170.

After that, when the temperature TB of the secondary battery 4 temporarily drops and TB<T2, step S161 returns No, the process returns to step S110, charging is stopped, and the secondary battery 4 enters a non-charging state.

In the example of FIG. 4, the temperature TB of the secondary battery 4 then rises, and the state becomes T2<TB<T1. However, before the reference time tr has elapsed since charging was stopped, the state becomes T1<TB, Yes, and it is determined in step S141 that T1≦TB, and charging is resumed in step S142.

As described above, in this embodiment, even if the temperature TB of the secondary battery 4 falls below the first threshold temperature T1 and enters a charging start prohibited state, charging starts when the temperature reaches or exceeds the lower second threshold temperature T2 after the reference time tr has elapsed. This brings forward the timing of the start of charging and extends the period of time available for charging. In other words, time efficiency is improved. Furthermore, because the temperature TB of the secondary battery 4 when charging is resumed is equal to or higher than the second threshold temperature T2, no damage is caused to the secondary battery 4.

(Embodiment 2)
In the first embodiment, when the temperature TB of the secondary battery 4 is lower than the second threshold temperature T2, charging of the secondary battery 4 is not started. However, there are some secondary batteries 4 for which the temperature TB of the secondary battery 4 rises in a short time when charging is started, and reaches a temperature suitable for charging. In view of this, a charging device 6 according to a second embodiment will be described, which once performs charging when the temperature TB of the secondary battery 4 is low, and then continues or interrupts charging depending on the change in the temperature TB of the secondary battery 4.

The basic configuration and basic operation of the electronic circuit of this embodiment are almost the same as those of the first embodiment shown in Figures 1 to 4. Therefore, the differences from the first embodiment will be mainly explained with reference to Figure 5.

In the second embodiment, a third threshold temperature T3 lower than the second threshold temperature T2 is preset in the ROM 623. The third threshold temperature T3 is set to a lower limit of the battery temperature that does not harm the secondary battery 4, for example, if charging for a short period of time. If the secondary battery 4 is composed of a lithium ion battery, the third threshold temperature T3 is set to, for example, -10°C. In this embodiment, no charging is performed unless the temperature TB related to the secondary battery 4 is equal to or higher than the third threshold temperature T3. The third threshold temperature T3 is a lower limit charging temperature that is an even lower temperature than the second threshold temperature T2, which is a certain lower limit charging temperature.

When the connection plug of the AC adapter 2 is connected to the input unit 3, the processor 621 sequentially stops charging (step S110), resets and starts the internal timer (step S120), and reads the temperature TB related to the secondary battery 4 (step S130), similar to the charging control process of FIG. 3.

Next, if it is determined in step S141 that TB<T1 (step S141: No), the processor 621 determines whether the temperature TB related to the secondary battery 4 is equal to or higher than the third threshold temperature T3 (step S201).

If it is determined in step S201 that the temperature TB of the secondary battery 4 is less than the third threshold temperature T3 (step S201: No), the temperature TB of the secondary battery 4 is low enough that it is not suitable for charging. Therefore, the process returns to step S130, and the same process is repeated. In this case, although the temperature TB of the secondary battery 4 is low, there is no damage to the secondary battery 4 because charging has not started.

On the other hand, if it is determined in step S201 that the temperature TB of the secondary battery 4 is equal to or higher than the third threshold temperature T3 (step S201: Yes), it is determined whether the elapsed time ts measured by the internal timer, i.e., the elapsed time ts since charging was stopped, is equal to or higher than the reference time tr (step S202).

If it is determined in step S202 that tr>ts (step S202: No), the process returns to step S130.

On the other hand, if it is determined in step S202 that tr≦ts (step S202: Yes), and if it is determined in step S141 that T1≦TB, charging is started (step S170). Therefore, at the start of charging, the temperature TB of the secondary battery 4 may be equal to or lower than the second threshold temperature T2. Here, steps S201 and S202 are an example of the first condition in the claims.

Next, the temperature data is read from the temperature sensor 5 (step S150), and it is determined whether the temperature TB for the secondary battery 4 indicated by the temperature data is equal to or higher than the second threshold temperature T2 (step S161).

If it is determined in step S161 that the temperature TB of the secondary battery 4 is equal to or higher than the second threshold temperature T2 (step S161: Yes), the charging circuit 61 is instructed to continue charging, and the process returns to step S170.

On the other hand, if it is determined in step S161 that the temperature TB of the secondary battery 4 is less than the second threshold temperature T2 (step S161: No), the process waits for a certain period of time (step S203). The processor 621 then reads out the history of the temperature TB of the secondary battery 4 stored in the RAM 622 and reads the most recent temperature data from the temperature sensor 5 (step S204). Next, the processor 621 determines whether the temperature TB of the secondary battery 4 is increasing, i.e., whether ΔTB is a positive value, or whether the temperature TB of the secondary battery 4 is decreasing, i.e., whether ΔTB is a negative value, based on the temperature data string that has been read out (step S205). If the temperature TB of the secondary battery 4 is increasing, i.e., if the temperature TB is rising, there is a possibility that the temperature TB of the secondary battery 4 will rise to a temperature at which it can be safely charged if the process waits for a while. Therefore, if the temperature TB of the secondary battery 4 is on an increasing trend (step S205: Yes), the process proceeds to S170. On the other hand, if the temperature TB of the secondary battery 4 is on a decreasing trend (step S205: No), there is little or no possibility that the temperature TB of the secondary battery 4 will rise to a temperature at which charging is possible, so the process proceeds to S110 and charging is stopped. Here, step S205 is an example of the second condition in the claims.

As described above, in this embodiment, the first threshold temperature T1 is basically set as the threshold temperature for determining whether charging can be started, and the second threshold temperature T2 is set as the threshold temperature for determining whether charging should be stopped, and hysteresis is provided to the threshold temperature. On the other hand, even if the temperature TB of the secondary battery 4 has not reached the first threshold temperature T1, if the non-charging state continues for a reference time tr or more, charging is performed once, and the degree of increase in the temperature TB thereafter is determined. If there is a high possibility that the temperature TB of the secondary battery 4 will rise to a temperature suitable for charging, charging is continued. This allows charging to be performed earlier or for a longer period of time, improving time efficiency.

The waiting process of step S203 may be placed between steps S170 and S150.

It is possible to evaluate the increase in temperature TB of the secondary battery 4 in more detail.

In step S205, the conditions for continuing charging and the conditions for stopping charging can be determined arbitrarily.
For example, a condition may be an arbitrary reference value<ΔTB.
The magnitude of the difference between the temperature TB at that time and the second threshold temperature T may also be included in the conditions.
Also, it may be determined that the condition for continuing charging is met when the change in battery temperature during standby time t2, ΔTB/t2, i.e., the rate of increase in temperature TB of secondary battery 4, i.e., the temperature increase rate, is greater than a reference value. Note that although it has been described here as the rate of increase being greater than the reference value, this means that the rate is higher than a reference that has an increasing tendency, and it may be specified by something other than a simple numerical value.

In addition, for example, the second derivative ^d2TB / ^dt2 of the change in temperature TB for the secondary battery 4 may be calculated, and when this is positive, i.e., when the slope of the temperature change is on the rise, the charging state may be started or continued even if ΔTB is negative.

In addition, the time required to reach the second threshold temperature T2 can be estimated from an approximation line of the temperature TB for the secondary battery 4, the estimated time can be compared with a reference value, and if the estimated time is less than the reference value, the condition can be set to start or continue the charging state.

In the above explanation, an example has been shown in which charging of the secondary battery 4 is started when it is determined in step S202 that tr≦ts (step S202: Yes). However, as shown in FIG. 6, it is also possible not to perform charging at this point.
In this case, when it is determined in step S205 that the condition 0<ΔTB is satisfied due to, for example, an increase in the ambient temperature, charging is started (step S170).

(Embodiment 3)
When the user connects the connection plug of the AC adapter 2 to the input unit 3, it is presumed that the user has a strong intention to charge the secondary battery 4. In this case, it may not be desirable to ignore the user's intention to charge simply based on temperature conditions. In this case, for example, immediately after connecting the plug to the input unit 3, it is desirable to charge the secondary battery 4, except when the temperature TB is extremely low.
A charging device 6 that can satisfy such demands will now be described with reference to FIG.

The basic configuration and basic operation of the electronic circuit according to this embodiment are almost the same as those shown in Figures 1 to 4. Therefore, the following description will focus on the differences.
In the present embodiment, after starting the charge control process, processor 621 first sets an initial flag in RAM 622 (step S100), and thereafter executes the above-mentioned steps S110 to S141.

Here, if it is determined in step S201 that T3≦TB (step S201: Yes), the processor 621 refers to the first flag set in the RAM 622 (step S211).

When a series of processes is executed for the first time after the start of the charge control process, it is determined in step S204 that the first flag is on.
When the processor 621 determines that the first flag is on (step S211: Yes), the process proceeds to step S170, and starts charging the secondary battery 4. The subsequent process is the same as the process in the second embodiment shown in FIG.

If the processor 621 determines in step S211 that the first-time flag is on (step S211: Yes), if the processor 621 determines in step S201 that T3>TB (step S201: No), or if the processor 621 determines in step S141 that T1≦TB (step S141: Yes), the processor 621 resets the first-time flag in the RAM 622.

With this configuration, the secondary battery 4 can be charged at a high rate immediately after the AC adapter 2 starts supplying power to the charging device 6. This allows the user's intention to be reflected. On the other hand, after a certain amount of charging has been performed, it becomes possible to implement charging control, including stopping charging, taking into account the temperature TB related to the secondary battery 4.

Note that, if it is determined that "Yes" is returned in step S201 after processing such as step S205 other than the first time, the charging start condition based on the elapsed time ts shown in step S202 of FIG. 5 may be used in combination. Also, charging may be started not only for the first time, but also up to a certain upper limit, such as the second or third time. Also, instead of starting charging after a certain time has elapsed, charging may be started within a certain time after the supply of power to the charging device 6 has started.

Although an example of using the first-time flag has been shown, it is also possible to measure the time that has elapsed since the AC adapter was connected, and for a certain period of time, the answer to step S211 may be Yes, giving priority to charging.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications and applications are possible.

In the above embodiment, an example was shown in which the power supply circuit is provided with a charging control unit 62, but if a similar control function can be realized, a DSP (Digital Signal Processor) or the like can also be used. In addition, the power supply circuit may be in the form of hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

The present invention allows for various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to explain the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is indicated by the claims, not by the embodiments. Furthermore, various modifications made within the scope of the claims and the scope of the meaning of the invention equivalent thereto are considered to be within the scope of the present invention. The inventions described in the original claims of this application are appended below.

(Additional Note)
(Appendix 1)
A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit includes:
when a temperature related to the secondary battery is less than a first threshold temperature and a first condition is satisfied, allowing charging of the secondary battery to commence;
A charging device which does not permit the start of charging of the secondary battery when the temperature relating to the secondary battery is lower than the first threshold temperature and does not satisfy the first condition.

(Appendix 2)
The charging device according to claim 1, wherein the first condition includes a state in which a temperature of the secondary battery is lower than the first threshold temperature for a first period of time or more.

(Appendix 3)
The charging device according to claim 1 or 2, wherein the first condition includes a condition that a temperature of the secondary battery when the first condition continues for the first time or longer is equal to or higher than a certain lower limit charging temperature.

(Appendix 4)
The charging device according to any one of Supplementary Notes 1 to 3, wherein the first condition includes a certain period of time after power is supplied to the charging circuit.

(Appendix 5)
The charging device according to any one of appendixes 1 to 4, wherein the first condition includes a condition that exists after charging has been performed once.

(Appendix 6)
The charging device according to any one of appendixes 1 to 5, wherein the first condition includes any one of the following: the temperature of the secondary battery is on an upward trend; a temperature increase rate is higher than a certain increase rate; and a slope of the temperature change is on an upward trend.

(Appendix 7)
The charging control unit causes a charging circuit to: i) allow charging of the secondary battery to begin when a temperature related to the secondary battery is equal to or higher than the first threshold temperature; and ii) stop charging of the secondary battery when the temperature related to the secondary battery falls below a second threshold temperature that is lower than the first threshold temperature.

(Appendix 8)
8. The charging device of claim 7, wherein the first condition includes a calculated time until the second threshold temperature is reached is less than a certain time.

(Appendix 9)
The charging device described in Appendix 7 or Appendix 8, wherein the charging control unit maintains a previous charging state and a non-charging state when a temperature related to the secondary battery is between the first threshold temperature and the second threshold temperature, provided that other conditions are satisfied.

(Appendix 10)
the charging control unit allows the start of charging of the secondary battery or continues charging when the temperature of the secondary battery is equal to or higher than the first threshold temperature;
The charging device according to any one of appendices 7 to 9, wherein, when the temperature relating to the secondary battery is lower than the second threshold temperature and a second condition is satisfied, continuation of charging is permitted.

(Appendix 11)
A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit controls the charging circuit,
When the temperature of the secondary battery is equal to or higher than a first threshold temperature, charging of the secondary battery is permitted to commence;
allowing the charging to continue when the temperature of the secondary battery is below a second threshold temperature that is lower than the first threshold temperature and satisfies a second condition;
The charging device stops charging when the temperature relating to the secondary battery is lower than the second threshold temperature and the second condition is not satisfied.

(Appendix 12)
The charging device described in Appendix 10 or Appendix 11, wherein the second condition includes any one of the following: the temperature of the secondary battery is on an upward trend; a temperature increase rate is higher than a certain increase rate; a temperature change slope is on an upward trend; and a calculated time until the second threshold temperature is reached is shorter than a certain time.

(Appendix 13)
13. The charging device according to any one of claims 1 to 12, wherein the secondary battery is a lithium ion battery, and the first threshold temperature is 5°C.

(Appendix 14)
13. The charging device according to any one of appendixes 7 to 12, wherein the secondary battery is a lithium ion battery, and the second threshold temperature is 0° C.

(Appendix 15)
The secondary battery;
An electronic device comprising: a charging device according to any one of claims 1 to 14.

(Appendix 16)
Measure the temperature of the secondary battery;
starting charging of the secondary battery when the temperature of the secondary battery is equal to or higher than a first threshold temperature and when the temperature of the secondary battery falls below the first threshold temperature and satisfies a first condition;
when the temperature of the secondary battery is less than the first threshold temperature and the first condition is not satisfied, charging of the secondary battery is not started;
when the temperature associated with the secondary battery falls below a second threshold temperature that is lower than the first threshold temperature;
The charging method further comprises: continuing charging the secondary battery when a second condition is satisfied; and stopping charging the secondary battery when the second condition is not satisfied.

(Appendix 17)
On the computer,
A process of measuring the temperature of the secondary battery;
i) a process of starting charging of the secondary battery when the temperature of the secondary battery is equal to or higher than a first threshold temperature and when the temperature of the secondary battery falls below the first threshold temperature and satisfies a first condition;
ii) a process of continuing to stop charging of the secondary battery when the temperature of the secondary battery is below the first threshold temperature and the first condition is not satisfied; and iii) a process of continuing charging of the secondary battery when the temperature of the secondary battery becomes below a second threshold temperature that is lower than the first threshold temperature and a second condition is satisfied, and stopping charging of the secondary battery when the second condition is not satisfied.

(Appendix 18)
The first condition is
the temperature of the secondary battery remains below the first threshold temperature for a certain period of time or more; a certain period of time has passed since power was supplied to a charging circuit; the temperature of the secondary battery is on an upward trend; the rate of temperature increase is higher than a certain rate of increase; the slope of the temperature change is on an upward trend; the calculated time until the second threshold temperature is reached is shorter than a certain period of time; or a condition that occurs after charging is once performed,
The second condition is
The charging method according to claim 16 or the computer program according to claim 17, including any one of the following: the temperature of the secondary battery is on an upward trend; the rate of temperature increase is higher than a certain rate of increase; the slope of the temperature change is on an upward trend; and the calculated time until the second threshold temperature is reached is shorter than a certain time.

1...Electronic device, 2...AC adapter, 3...Input unit, 4...Secondary battery, 5...Temperature sensor, 6...Charger, 61...Charger circuit, 62...Charger control unit, 621...Processor, 622...RAM, 623...ROM, 624...I/O, 625...Bus, T1...First threshold temperature, T2...Second threshold temperature, T3...Third threshold temperature, TB...Temperature related to the secondary battery, t2...Waiting time, tr...Reference time, ts...Elapsed time

Claims (10)

A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit is
the charging circuit permits charging of the secondary battery when a temperature related to the secondary battery is less than a first threshold temperature and a first condition related to the temperature of the secondary battery is satisfied;
when the temperature related to the secondary battery is less than the first threshold temperature and the first condition is not satisfied, charging of the secondary battery is not permitted;
a charging circuit that: i) permits charging of the secondary battery when a temperature related to the secondary battery is equal to or higher than the first threshold temperature; and ii) stops charging of the secondary battery when the temperature related to the secondary battery falls below a second threshold temperature that is lower than the first threshold temperature;
The first condition is that the calculated time to reach the second threshold temperature is less than a certain time.
Charging device. A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit is
the charging circuit permits charging of the secondary battery when a temperature related to the secondary battery is less than a first threshold temperature and a first condition related to the temperature of the secondary battery is satisfied;
when the temperature related to the secondary battery is less than the first threshold temperature and the first condition is not satisfied, charging of the secondary battery is not permitted;
a charging circuit that: i) permits charging of the secondary battery when a temperature related to the secondary battery is equal to or higher than the first threshold temperature; and ii) stops charging of the secondary battery when the temperature related to the secondary battery falls below a second threshold temperature that is lower than the first threshold temperature;
When the temperature of the secondary battery is lower than the second threshold temperature, a fixed time is waited, and after waiting for the fixed time, charging is permitted if any of the following conditions is satisfied: the temperature of the secondary battery is on an increasing trend, the rate of temperature increase is higher than a certain rate of increase, the gradient of the temperature change is on an increasing trend, and the calculated time until the second threshold temperature is reached is shorter than a certain time.
Charging device. 3. The charging device according to claim 2, wherein the first condition is that a state in which the temperature of the secondary battery is lower than the first threshold temperature continues for a first period of time or more, and that the temperature of the secondary battery when this state continues for the first period of time or more is equal to or higher than a lower limit charging temperature. 3. The charging device according to claim 2, wherein the first condition is one of the following: charging is performed once, and after the charging is performed, the temperature of the secondary battery is on an upward trend, a temperature increase rate is higher than a certain increase rate, or a slope of the temperature change is on an upward trend. A charging circuit for charging the secondary battery;
a temperature information acquisition unit that acquires temperature information indicating a temperature related to the secondary battery, and a charge control unit that controls the charging circuit based on the temperature information acquired by the temperature information acquisition unit;
The charging control unit controls the charging circuit,
When the temperature of the secondary battery is equal to or higher than a first threshold temperature, charging of the secondary battery is permitted;
permitting charging when the temperature of the secondary battery is less than a second threshold temperature that is lower than the first threshold temperature and a second condition regarding the temperature of the secondary battery is satisfied;
When the temperature of the secondary battery is less than the second threshold temperature and the second condition is not satisfied, charging is stopped;
The second condition is any one of the following: the temperature of the secondary battery is increasing; the rate of temperature increase is higher than a certain rate of increase; the slope of the temperature change is increasing; and the calculated time until the second threshold temperature is reached is shorter than a certain time.
Charging device. The charging device according to claim 1 , wherein the secondary battery is a lithium ion battery, and the first threshold temperature is 5° C. The charging device according to claim 1 , wherein the secondary battery is a lithium ion battery, and the second threshold temperature is 0° C. The secondary battery;
An electronic device comprising: the charging device according to any one of claims 1 to 7 . Measure the temperature of the secondary battery;
charging the secondary battery when the temperature of the secondary battery is equal to or higher than a first threshold temperature and when the temperature of the secondary battery is below the first threshold temperature and satisfies a first condition related to the temperature of the secondary battery;
When the temperature of the secondary battery is less than the first threshold temperature and the first condition is not satisfied, the secondary battery is not charged;
when the temperature of the secondary battery falls below a second threshold temperature that is lower than the first threshold temperature, charging the secondary battery when a second condition related to the temperature of the secondary battery is satisfied, and stopping charging the secondary battery when the second condition is not satisfied;
The first condition is
any one of the following: the temperature of the secondary battery remains below the first threshold temperature for a certain first period of time or more; the temperature of the secondary battery is on an increasing trend; the rate of temperature increase is higher than a certain rate of increase; the slope of the temperature change is on an increasing trend; and the calculated time until the second threshold temperature is reached is shorter than a certain period of time.
The second condition is
The temperature of the secondary battery is on an increasing trend, the rate of temperature increase is higher than a certain rate of increase, the slope of the temperature change is on an increasing trend, or the calculated time until the second threshold temperature is reached is shorter than a certain time.
How to charge? On the computer,
A process of measuring the temperature of the secondary battery;
i) charging the secondary battery when the temperature of the secondary battery is equal to or higher than a first threshold temperature and when the temperature of the secondary battery is below the first threshold temperature and satisfies a first condition related to the temperature of the secondary battery;
ii) a process of continuing to stop charging of the secondary battery when the temperature of the secondary battery is below the first threshold temperature and the first condition is not satisfied; and iii) a process of charging the secondary battery when the temperature of the secondary battery becomes below a second threshold temperature that is lower than the first threshold temperature and a second condition related to the temperature of the secondary battery is satisfied, and a process of stopping charging of the secondary battery when the second condition is not satisfied ,
The first condition is
any one of the following: the temperature of the secondary battery remains below the first threshold temperature for a certain first period of time or more; the temperature of the secondary battery is on an increasing trend; the rate of temperature increase is higher than a certain rate of increase; the slope of the temperature change is on an increasing trend; and the calculated time until the second threshold temperature is reached is shorter than a certain period of time.
The second condition is
The temperature of the secondary battery is on an increasing trend, the rate of temperature increase is higher than a certain rate of increase, the slope of the temperature change is on an increasing trend, or the calculated time until the second threshold temperature is reached is shorter than a certain time.
Computer program.