JP6161919B2 - Quick charger with thermal escape prevention function - Google Patents

Description

  The present invention relates to a technology of a charging device for charging a secondary battery such as a lithium battery, a lithium ion battery, a nickel-cadmium battery, a nickel-hydrogen metal battery, or a lead storage battery. In particular, the present invention relates to a rapid charging apparatus with a thermal escape prevention function capable of rapidly charging while preventing the occurrence of thermal escape that has been a problem in the past.

  As the use of electronic devices increases, a wide variety of batteries are used in particular, such as small power sources for portable electronic devices, uninterruptible power sources (UPS) for systems that cannot be stopped, and power sources for electric vehicles. The battery of portable electronic devices is not a so-called disposable battery, but a secondary battery, that is, a rechargeable battery that can be repeatedly charged / discharged. Development is underway.

In order for the secondary battery to exhibit the performance as specified, it is necessary to control not only the usage environment conditions of these electronic devices but also the charging conditions for repeated charging of the secondary battery. In particular, it is important for the charging condition to charge “rapidly” and “to full charge capacity” without damaging the discharged battery. For this reason, a charging method suitable for each type and use of the secondary battery has been studied, including a detection method at the completion of charging, a method for preventing overcharging, and the like.
A typical charging method in the prior art will be described.
As the secondary battery, a lithium ion battery having a cobalt composite oxide as a positive electrode will be described as an example. The maximum charging voltage of the lithium ion battery is 4.2V.

First, there is a constant voltage charging method as one of the charging methods in the prior art.
The constant voltage charging method is a method in which a constant voltage (4.2 V in this example) is applied to a battery from a charger. According to this constant voltage charging method, there is a merit that a simple device configuration is sufficient because only a constant voltage of 4.2 V is applied from the charger.

FIG. 11A is a diagram simply showing an outline of the charging characteristics of the time variation of the secondary battery voltage and the time variation of the charging current when charging is performed using the constant voltage charging method. In the figure, the vertical axis represents the charging battery voltage or charging current, and the horizontal axis represents time.
However, this constant voltage charging method has a major drawback. As shown in FIG. 11A, there is a problem that a large current flows in the initial stage of charging and the secondary battery may be damaged. In addition, although the current decays in the second half of the charging period, there is a problem that it takes time until the charging capacity is sufficiently satisfied. Therefore, a device for suppressing the initial current and increasing the current in the latter half is required.

In the constant voltage charging method, there is a method in which the applied voltage is set to the rated voltage (rated full charge equilibrium voltage value) to suppress the initial current. In the case of this rated voltage charging, the charging characteristics are as shown in FIG.
FIG. 11B is a diagram simply showing the outline of the charging characteristics of the time variation of the secondary battery voltage and the time variation of the charging current when charging is performed by rated voltage charging. In the figure, the vertical axis represents the charging battery voltage or charging current, and the horizontal axis represents time.
When charging with rated voltage charging, energization of a large current at the beginning of charging is suppressed, but its charging characteristics are so-called long tail type that gradually attenuates over time, and the charging capacity is sufficient The problem that it takes time to be satisfied still remains.

Next, there is a constant current / constant voltage charging method as one of the charging methods in the prior art.
The constant current / constant voltage charging method uses constant current charging for a while after the start of charging, and switches to constant voltage charging at the rated voltage (rated full charge equilibrium voltage value) after the secondary battery voltage reaches the specified voltage. is there. This constant-current / constant-voltage charging method has the advantage that it can be charged at a relatively high speed, and there is no overcharge even at the beginning of the charging period. There is an advantage that overcharging does not occur as long as the application of the charging equilibrium voltage value).
A constant current / constant voltage charging technique is adopted for a lithium secondary battery in which the organic electrolyte is likely to be decomposed in a high voltage overcharge state.
If the battery configuration can be devised so as to allow even a large current value during constant current charging, the charging time can be further shortened.

FIG. 12 is a diagram simply showing an outline of the charging characteristics of the time variation of the secondary battery voltage and the time variation of the charging current when charging is performed using the constant current / constant voltage charging method. In the figure, the vertical axis represents the charging battery voltage or charging current, and the horizontal axis represents time. In the case of a lithium ion battery having a cobalt composite oxide as a positive electrode, constant current charging is performed up to 4.2V, and after the voltage of the secondary battery is 4.2V, constant voltage charging is performed at 4.2V. ing.
As shown in FIG. 12, according to the constant current / constant voltage charging method, compared with the constant voltage charging method shown in FIG. 11, a large charge amount in the constant current region from the initial stage of the charging period to the middle stage is secured. Thus, there is an advantage that the charging period is relatively short.

  However, even with the constant current constant voltage charging method, there still remains a problem that the charging time becomes long. As shown in FIG. 12, since charging is performed at the rated current in the constant current region in the initial stage of charging, energization of a large current in the initial stage of charging is suppressed, and the current value decreases in the subsequent constant voltage region. The charging characteristic has a problem that the charging time is shorter than the rated voltage charging, but the charging time is still long, and it takes time until the charging capacity is sufficiently satisfied.

Japanese Patent Laid-Open No. 06-225466

  In general, if a secondary battery is charged at a charging voltage higher than the specified rated voltage, charged at a charging current higher than the specified rated current, or charged longer than the rated time, it will be overcharged. It is known that various problems may occur when overcharge occurs. For example, when the overcharged state continues, there arises a problem that metallic lithium is deposited on the negative electrode or the positive electrode is dissolved by excessive extraction of lithium ions. Furthermore, a problem that the electrolytic solution is decomposed and a fire due to heat generation may occur. The chemical reaction caused by overcharging (deposition of metallic lithium on the negative electrode or dissolution of the positive electrode) is an irreversible reaction, which reduces the charging capacity of the charger and degrades the charger. It will be shorter.

In order to avoid overcharge, the control of the charger is set in accordance with the battery. Therefore, charging should be performed at the rated voltage, rated current, and rated time set for each charger. In the constant voltage charging method and the constant current constant voltage charging method described above, charging is performed at the rated voltage, rated current, and rated time set for each charger.
However, regardless of which of these constant voltage charging method and constant current constant voltage charging method described above, the type of secondary battery, individual differences, the influence of secondary battery usage, the degree of deterioration of the secondary battery There are major problems such as overcharge due to the type of secondary battery to be charged, individual differences, the influence of the state, and "heat escape".

  In other words, in these charging methods, if the method for determining the charging end timing is uniformly applied ignoring the state of the secondary battery, there will be a problem of overcharging or thermal escape depending on the type, individual difference, or internal state of the secondary battery. Can occur. For example, characteristics during charging differ depending on the type of secondary battery, such as a difference in electrode structure, a difference in electrode metal, and a difference in electrolyte type. Furthermore, even for secondary batteries of the same type and the same model number, their characteristics vary greatly depending on differences in environmental conditions during charging, the degree of deterioration of the secondary battery, the electrochemical state, and the like. For this reason, charging with the same uniform pattern may result in overcharging, and as a result, an abnormal chemical reaction is generated inside the secondary battery, resulting in heat generation, that is, thermal escape occurs, and electric energy is heated. Since it is converted into energy, there is a possibility that the charging efficiency may be reduced. In particular, in recent years, aiming at shortening the charging time, in many cases, efficient charge control is performed near the rated voltage and rated current, and therefore it can be said that the battery is easily influenced by individual differences and state differences of secondary batteries. As a result, there is a need for a preventive measure for the occurrence of defects such as thermal escape.

  Therefore, the present invention has been made in view of the above circumstances, and prevents thermal runaway that can prevent overcharge and thermal runaway during charging that can occur due to differences in the type, individual difference, and internal state of the secondary battery. An object is to provide a quick charger with a function.

In order to achieve the above object, a quick charger with a thermal runaway prevention function according to the present invention includes a charging means for supplying a charging voltage or charging current to a secondary battery, and a voltage detecting means for detecting a terminal voltage of the secondary battery. And a current detection means for detecting a current value of a charging current passed through the secondary battery, and a charging control device for controlling the charging voltage or the charging current of the charging means, wherein the charging control device is charged In a rapid charging apparatus that performs constant current and constant voltage charging control using a rated voltage and a rated charging current of the secondary battery that is a target, the charging control apparatus generates thermal escape in a charged state of the secondary battery. with a heat runaway detection means for predicting or sensing, the charge control device, and the constant current constant voltage charging control to be applied to the normal time of the heat escape detection means does not predict or detect the occurrence of the heat escape With a heat runaway control applied by switching from the constant current constant voltage charging control if thermal runaway occurs predicted or detected the heat escape detection means, with thermal runaway prevention function, wherein the controller controls the charging device It is a quick charging device.
Here, the thermal escape control is switched and started when the increase of the charging current is detected by the current detection means in the constant voltage region of the constant current constant voltage charging control.
The charge control device predicts the occurrence of thermal escape in advance by switching the constant current and constant voltage charge control and the thermal escape control based on the detection or detection of thermal escape of the thermal escape detection means to control the charging means, or The occurrence of the problem of thermal escape can be reliably avoided by detecting the occurrence of thermal escape.

As an example of the thermal escape control , the thermal escape detection means starts the thermal escape control when the increase of the charging current is detected by the current detection means in the constant voltage range of the constant current constant voltage charge control. As thermal escape control , a charging current limit value update procedure for reducing the charging current limit value in the constant current constant voltage charge control in a constant voltage range by a certain amount, and then whether the charging current is increased again in the current detection means. And the charging current limit value updating procedure by repeating a monitoring procedure for monitoring the charge current limit value by a certain amount in the charging current limit value updating procedure if the charging current increases again in the monitoring procedure. This is a control to stop the charging of the secondary battery via the charging means when the number of executions reaches a certain number of times.

  In the constant voltage range of constant current constant voltage charge control, if an increase in charging current is seen, it can be predicted that a thermal runaway has occurred or that an abnormal situation such as heat generation leading to a thermal runaway is occurring, the present invention If this increase in charging current is detected, the charging control device transitions to thermal escape suppression control. In the case of the second thermal escape suppression control, if an increase in the charging current is observed, charging is not stopped immediately, and thermal escape may not occur due to a temporary malfunction or a temporary chemical phenomenon. The device is devised to provide a period during which monitoring is continued while changing the charging current limit value.

As another example of thermal escape control, thermal escape suppression control is started when a decrease in charging voltage is detected by the voltage detection means in the constant current region or constant voltage region of constant current constant voltage charging control. There is a charge current limit value update procedure for reducing the charge current limit value in the constant current constant voltage charge control in the constant voltage range by a certain range as the thermal escape control , and then the charge voltage is again set in the voltage detection means. A monitoring procedure for monitoring whether to decrease, and if the charging voltage is decreased again in the monitoring procedure, the charging current limit value updating procedure is repeated to decrease the latest charging current limit value by a certain amount, and the charging current limit This is control for stopping charging of the secondary battery via the charging means when the value update procedure has been executed a certain number of times or more.

  In the constant voltage range of constant current constant voltage charging control, if a decrease in charging voltage is seen, it can be predicted that a thermal runaway has occurred or that an abnormal situation such as heat generation leading to a thermal runaway is occurring, the present invention If this decrease in the charging voltage is detected, the charging control device transitions to thermal escape suppression control. In addition, in the case of the fourth thermal escape suppression control, if a decrease in the charging voltage is observed, charging is not immediately stopped, and thermal escape may not be caused by a temporary malfunction or a temporary chemical phenomenon. The device is devised to provide a period during which monitoring is continued while changing the charging current limit value.

The following control is also possible as general control.
As an example of the thermal escape control , the first thermal escape control is started when the increase of the charging current is detected by the current detection means in the constant voltage region of the constant current constant voltage charging control. As the thermal escape control , there is an example in which the charging to the secondary battery via the charging unit is immediately stopped.
Next, as another example of the thermal escape control , the third thermal escape control is started when the voltage detection means detects the decrease in the charging voltage in the constant current region or the constant voltage region of the constant current constant voltage charging control. As the third thermal escape control , there is an example in which charging to the secondary battery via the charging means is immediately stopped.
Next, as another example of thermal escape control, in the constant voltage region of constant current constant voltage charging control, it is detected that the current detection means detects that the rate of decrease in charging current is below a predetermined value and the detection. The fifth thermal escape control is started in relation to such a time zone. As the fifth thermal escape control , there is an example in which charging to the secondary battery via the charging unit is immediately stopped.

  As another example of the thermal escape control standard, in the constant voltage region of constant current constant voltage charge control, it is detected that the current detection means detects that the rate of decrease of the charging current has become a predetermined value or less. Example of starting the sixth thermal escape suppression control in relation to such a time zone, and as the sixth thermal escape suppression control, stopping charging the secondary battery via the charging means after elapse of a predetermined time There is.

  In the constant voltage range of constant current / constant voltage charging control, if the rate of decrease in charging current is below the default value, if charging continues, the charging current will be reversed to increase, and further heat generation will lead to thermal escape. It can be predicted that an abnormal situation is occurring. In the present invention, if it is detected that the rate of decrease in the charging current is less than or equal to a predetermined value, the charging control device transitions to thermal escape suppression control, and can be controlled to stop charging immediately or at a constant level. It is also possible to control charging after a lapse of time.

  In addition, as another example of the heat escape control standard, in the constant voltage region of the constant current constant voltage charging control, it has been detected by the current detection means that the charging current does not decrease to a predetermined value even after a predetermined time, Alternatively, the seventh thermal escape suppression control is started when it is detected that the time during which the charging current decreases to a predetermined value is longer than the expected rated charging time. As the suppression control, there is an example in which charging to the secondary battery via the charging unit is immediately stopped.

  In addition, as another example of the heat escape control standard, in the constant voltage region of the constant current constant voltage charging control, it has been detected by the current detection means that the charging current does not decrease to a predetermined value even after a predetermined time, Alternatively, the eighth thermal escape control is started when it is detected that the time for the charging current to drop to a predetermined value is longer than the expected rated charging time. There is an example in which the suppression control stops charging the secondary battery via the charging means after a predetermined time has elapsed.

  In the constant voltage range of constant current / constant voltage charging control, if the charging current drop exceeds the preset value, if charging continues, the charging current will be reversed to increase, and further heat generation will lead to thermal escape. It can be predicted that an abnormal situation is occurring. In the present invention, if it is detected that the reduction width of the charging current is equal to or greater than a predetermined value, the charging control device transitions to the thermal escape suppression control, and it is possible to perform control to stop charging immediately, or to make a constant It is also possible to control charging after a lapse of time.

According to the rapid charging device with the thermal escape prevention function of the present invention, the charging control device switches between two controls of constant current and constant voltage charging control and thermal escape control based on thermal escape occurrence prediction or detection of the thermal escape detection means. By applying the control and controlling the charging means, it is possible to predict the occurrence of thermal escape in advance or detect the occurrence of thermal escape and reliably avoid the problem of thermal escape.
According to the rapid charging apparatus with a thermal runaway prevention function of the present invention, the constant of the constant current constant voltage charging control or the constant voltage range, the charging current increases, the charging voltage decreases, and the charging current decreases at a large rate of change. By keeping the magnitude of the change in the decrease in the charging current as the thermal escape control, the thermal escape detection means is causing the thermal escape or the abnormal situation such as the heat generation leading to the thermal escape is occurring. is with unpredictable, the invention if you get a detection or prediction of the thermal runaway, it is possible to charge control device transits to thermal runaway control, it controls the charging so as to suppress thermal runaway.

Hereinafter, the best mode for carrying out the present invention will be described specifically by way of examples. The scope of the technical idea of the present invention is not limited to the specific shapes and numerical values of these examples.
The rapid charging apparatus with a thermal runaway prevention function of the present invention is applied to a charging apparatus for charging a secondary battery. If it is a secondary battery, it will not specifically limit but it can apply widely. As an example, it will be understood that even a lithium battery, a lithium ion battery, a nickel-cadmium battery, a nickel-hydrogen metal battery, a lead storage battery, and the like can be applied. Unless otherwise specified, a lithium battery will be described below as an example.
In addition, the charge control is basically assumed to be constant current / constant voltage charge control, and the heat escape suppression control is incorporated.

First, an outline of the occurrence of the thermal escape phenomenon will be described, then each component of the rapid charging apparatus 1 with a thermal escape prevention function will be described, and then the operation of the rapid charging apparatus 1 with a thermal escape prevention function will be described. A bird's-eye view of the flow.
The thermal escape control in claim 1 is exemplified as the second thermal escape control below, and the thermal escape control in claim 2 is exemplified as the fourth thermal escape control.
Further, the term “control reference” simply means “control” or “control procedure”.

First, FIG. 1 is a diagram for explaining the outline of the occurrence of a thermal escape phenomenon.
Although the thermal escape phenomenon can occur in various charging methods, here, the thermal escape phenomenon that occurs in a charging device adopting a constant current constant voltage charging method will be described.

Thermal escape during charging of a secondary battery refers to the following phenomenon.
When charging a battery, the charging current usually decreases for a while in the constant voltage region as the battery electromotive voltage increases due to the progress of charging. However, due to factors such as battery deterioration, the battery temperature rises during charging. Along with this, there may be a phenomenon in which a current increase phenomenon occurs from the time when the charging current decreases to some extent, or a phenomenon in which the charging voltage decreases with a high current without decreasing the current. If charging is continued with a large current when the temperature of the secondary battery is high, the secondary battery has an internal resistance, so the temperature of the secondary battery further increases due to the large current. There may be a vicious circle in which the charging voltage decreases. This phenomenon is called “heat escape”. When thermal runaway occurs in charging the battery, the battery temperature rises rapidly, which may cause a problem of further deteriorating the battery and shortening the battery life.

  FIG. 1 is a diagram illustrating charging characteristics when a constant current constant voltage charging method is employed. As shown in FIG. 1, when a secondary battery without significant deterioration is charged, it is in a “constant current region” from the beginning of charging to the middle stage, and then in a “constant voltage region” until the end of charging. Yes.

  In the constant current region, the charging current Ic passed from the charging means to the secondary battery is passed to the secondary battery as a constant current at the value of the rated current Io. At that time, the charging voltage Ec applied from the charging means to the secondary battery is controlled to gradually increase so that the rated current Io flows through the secondary battery.

  The charging voltage Ec applied from the charging means to the secondary battery gradually reaches the rated voltage Eo as it gradually increases so that the rated current Io flows. Here, it is assumed that the internal voltage E appearing at the terminal of the secondary battery also gradually increases and reaches, for example, E (1). Here, the increase in the charging voltage Ec applied from the charging means to the secondary battery is stopped, and a transition is made to a constant voltage region in which the rated voltage value Eo is maintained as a constant voltage.

In the constant voltage range, the charging current Ic to the secondary battery is a rated voltage value Eo that is a charging voltage applied from the charging means to the secondary battery, and an internal voltage E (1) that appears at the terminal of the secondary battery. Since the internal voltage E (1) flowing due to the potential difference and appearing at the terminal of the secondary battery is gradually boosted as the charging progresses, the charging current Ic to the secondary battery gradually decreases as shown in FIG. Will flow.
Due to factors such as individual differences of secondary batteries and deterioration of secondary batteries, the charging current Ic to the secondary battery in the constant voltage range decreases according to a curve according to charging characteristics such as Ic1, Ic2, and Ic3. Become.

  However, when the phenomenon of thermal escape described above occurs, various patterns can occur in FIG.

  For example, there is a thermal escape curve such as curve A shown in FIG. A thermal escape curve such as curve A is a curve in which the charging current once decreases and then increases in the constant voltage region of constant current constant voltage charging control. Thus, it can be determined that there is a possibility that the current increase phenomenon may have started a thermal runaway with the temperature rise of the secondary battery at the time of charging. In the rapid charging apparatus of the present invention, the phenomenon of drawing the thermal escape curve of curve A is one of the thermal escape control standards (hereinafter referred to as “thermal escape control standard 1”). .

  Further, for example, there is a thermal escape curve such as a curve B shown in FIG. A thermal runaway curve such as curve B is a case where a phenomenon occurs in which the current once drops slightly and then rises back to the maximum current in the constant voltage region of constant current constant voltage charging control. The curve is such that the rated voltage Eo cannot be maintained and decreases. Therefore, if a voltage drop phenomenon is detected in which the charging voltage drops without being able to maintain the rated voltage Eo in this way, the charging current flows at the maximum current, and heat increases with the temperature rise of the secondary battery during charging. It can be determined that the runaway may have begun. In the rapid charging apparatus of the present invention, the phenomenon of drawing the thermal escape curve of curve B is one of the thermal escape control standards (hereinafter, referred to as “thermal escape control standard 2”). .

  Here, if the charging characteristic curve as shown in FIG. 1 is analyzed, it is possible to predict that there is a possibility that thermal escape may occur if charging is continued as it is, although thermal escape has not yet occurred in the secondary battery. In some cases.

For example, the following can be predicted by analyzing the thermal escape curve A shown in FIG.
After the transition to the constant voltage range, if it is detected that the rate of decrease of the charging current suddenly decreases in a time period earlier than the scheduled rated charging time (for example, T1 to T2 in the figure), thermal escape occurs. It is predicted that there is a fear. When there is a change in the charging current along the thermal escape curve A, it can be seen that even if the charging current does not actually increase, the rate of decrease in the charging current suddenly decreases before the charging current starts to increase. If the phenomenon in which the rate of decrease in charging current suddenly decreases is near the end of the rated charging time, it can be said to be a normal decreasing phenomenon, but the decreasing phenomenon is detected in a time zone earlier than the scheduled rated charging time. If it is done, it can be predicted that the charging current has just increased and is just before the heat escape. This prediction is set as one of the thermal escape control standards (hereinafter referred to as “thermal escape control standard 3”).

For example, the following can be predicted by analyzing the thermal escape curve B shown in FIG.
After the transition to the constant voltage range, it is detected that the charging current does not decrease to a predetermined value (for example, Ia in the figure) even if a predetermined time (for example, T2 in the figure) elapses, or the charging current is a predetermined value ( For example, when it is detected that the time to decrease to Ia in the figure is longer than the expected rated charging time (for example, T2 in the figure) (for example, T3 in the figure), there is a possibility that thermal escape may occur. It is to be predicted that there is. One pattern of thermal escape is that the charging current does not converge as planned, but the charging current does not drop easily and the heat escapes as it is, or the charging current drops to a specified value but takes an abnormally long time. There is a pattern that turns into thermal runaway afterwards. If these phenomena can be detected, it can be predicted that they are just before heading for thermal escape. This prediction is set as one of the thermal escape control standards (hereinafter referred to as “thermal escape control standard 4”).

  In the rapid charging apparatus with a thermal escape prevention function of the present invention, thermal escape control is performed using the above-described various thermal escape control criteria. In this embodiment, it is assumed that the thermal escape detection means 1 is equipped with the thermal escape control reference 1 to the thermal escape control reference 4.

FIG. 2 is a diagram schematically illustrating a basic configuration of the rapid charging apparatus 1 with a thermal escape prevention function according to the first embodiment. In order to make each component easy to understand, the illustration is simplified as appropriate.
As shown in FIG. 2, the rapid charging apparatus 100 with a thermal escape prevention function of the present invention includes each component of a charging means 110, a voltage detection means 120, a current detection means 130, a charge control device 140, and a thermal escape detection means 150. I have. Note that the secondary battery 200 is also shown.

  The charging means 110 is capable of supplying a charging voltage or a charging current to the secondary battery 200 at a specified charging voltage E or charging current I according to the control of a charging control device 140 described later. It is a component.

  The voltage detection unit 120 is an electrical component that is connected to the connection terminal of the secondary battery 200 and can detect the internal voltage of the secondary battery 200.

  The current detector 130 is an electrical component that is arranged around the secondary battery 200 so as to detect the value of the charging current flowing through the secondary battery 200 and can detect the charging current to the secondary battery 200. .

  The charging control device 140 is an electrical component that controls the charging voltage or charging current supplied to the secondary battery 200 by controlling the charging unit 110. Charging is performed at the values of the charging voltage E and the charging current I specified by the charging control device 140 in conjunction with the charging control device 140 and the charging means 110.

In this configuration example, the charge control device 140 is intended essentially to perform constant-current constant-voltage charging control by using the rated voltage Eo and the rated charging current Io of the secondary battery 200 in the charged object, the normal state Applied constant current and constant voltage charging control (control during normal operation) .

  The thermal escape detection means 150 is for the charge control device 140 to predict or detect the occurrence of thermal escape in the charged state of the secondary battery 200, and has a thermal escape control reference for detecting thermal escape. In this configuration example, the thermal escape detection means 150 is included in the charge control device 140.

In this configuration example, as shown in FIG. 2, the charging control device 140 includes a thermal escape detection unit 150, and constant current and constant voltage charging control and thermal escape control based on prediction or detection of thermal escape occurrence of the thermal escape detection unit 150. It is a mechanism that can detect or predict thermal escape by switching .

Hereinafter, a flow of charging control of the secondary battery 200 by the quick charging device 100 with a thermal escape prevention function of the present invention will be described.
FIG. 3 and FIG. 4 are diagrams (part 1 and part 2) for explaining an example of the flow of the thermal escape suppression process by the rapid charging apparatus 100 with a thermal escape prevention function.

It is assumed that the charging of the secondary battery 200 to be charged by the rapid charging apparatus 100 with the thermal escape prevention function of the present invention shows the change of the charging curve A as shown in FIG.
Normal electrical connection between the rapid charging apparatus 100 with a thermal escape prevention function of the present invention and the secondary battery 200 is ensured, and charging of the secondary battery 200 is started (FIG. 3 (b), step S301). The progress of charging of the secondary battery 200 is monitored by the voltage detection means 120 and the current detection means 130.

  Here, it is assumed that the charging progresses, shifts from the constant current region to the constant voltage region, and further reaches the point a of the charging characteristic in FIG. By detecting this point a, an increase in the charging current Ic is detected by the current detection means 130 in the constant voltage region of the constant current constant voltage charging control (FIG. 3 (b), step S302: Y).

  The “thermal escape control standard 1” provided in the thermal escape detection means 150 is “when the increase in the charging current Ic is detected in the constant voltage region of the constant current constant voltage charge control, the thermal escape suppression control is started”. That's it.

  In response to the detection of the occurrence of thermal escape by the thermal escape detection means 150, the charging control device 140 starts “thermal escape suppression control” based on the thermal escape control reference 1 (step S303 in FIG. 3B).

  Here, two types of “first thermal escape suppression control” and “second thermal escape suppression control” will be described as “thermal escape suppression control”. Either one of the processing programs may be installed in the charging control device 140, or one of them may be selected.

  The example of “first thermal escape suppression control” is to immediately stop the charging of the secondary battery 200 via the charging unit 110. This is the simplest process as shown in FIG.

  The example of “second thermal runaway suppression control” does not stop charging immediately even if an increase in charging current is seen, and may not lead to thermal runaway due to a temporary malfunction or chemical phenomenon. For this reason, it is devised to provide a period during which monitoring is continued while changing the charging current limit value.

FIG. 4 shows the flow of processing when performing “second thermal escape control ”.
In FIG. 4, steps S301 to S303 are shown again. When “second heat escape control ” is started, the charging current limit value in constant current constant voltage charge control (normal control), which is normal control, is reduced by a certain amount in order to see the situation for a while. The “current limit value updating procedure” (step S401) and the “charging current monitoring procedure” (step S402) for monitoring whether the charging current in the current detecting means 130 increases thereafter are repeated, and the current detecting means 130 again. It is checked whether or not an increase in the charging current Ic has been detected (step S404). If the increase in the charging current Ic is resolved, the increase in the charging current Ic is resumed as a temporary phenomenon (see FIG. Step S404: N, go to Step S301) If the increase in the charging current Ic is not eliminated, the "charging current limit value update procedure" (Step S401) and The execution of the “current monitoring procedure” (step S402) will be repeated, and if it exceeds a certain number of times (step S403: Y), it is determined that a thermal runaway has occurred, and the charging control device 140 is charged. The charging process to the secondary battery 200 via 110 is terminated. The number of times follows the operation standard, but for example, about three times. If an increase in the charging current in the current detection means 130 is detected three times in succession, it can be determined that a thermal runaway has occurred, not a malfunction or a temporary chemical phenomenon, and the secondary battery 200 via the charging means 110 can be determined. It is set as the process which stops charge of.
After the “first thermal escape control ” shown in FIG. 3B or the “second thermal escape control ” shown in FIG. 4 is executed, the charging control device 140 controls the charging means 110 to perform charging. The process ends.

Next, another example of the flow of heat escape suppression processing will be described.
FIGS. 5 and 6 are diagrams (part 3 and part 4) for explaining an example of the flow of heat escape suppression processing by the rapid charging apparatus 100 with a heat escape prevention function.

It is assumed that the charging of the secondary battery 200 to be charged by the rapid charging apparatus 100 with the thermal escape prevention function of the present invention shows the change of the charging curve B1 or B2 as shown in FIG.
Normal electrical connection between the rapid charging apparatus 100 with a thermal escape prevention function of the present invention and the secondary battery 200 is ensured, and charging of the secondary battery 200 is started (FIG. 5 (b), step S501). The progress of charging of the secondary battery 200 is monitored by the voltage detection means 120 and the current detection means 130.

Here, two patterns are shown in FIG. 5A as patterns of thermal escape. One is a case where a decrease in charging voltage is observed due to the pattern B1. The pattern B1 is a case where the phenomenon is that the charging voltage Ec starts to drop despite the fact that it is originally in the constant current region and before the transition to the constant voltage region. It is assumed that it is detected that the charging voltage Ec has dropped to the point b1 even though the charging characteristic Eo in FIG. By detecting this point b1, the voltage detection means 120 detects a decrease in the charging voltage Ec in the constant current region of the constant current constant voltage charging control (step S502 in FIG. 5 (b)).
Another pattern is a case where a decrease in charging voltage is observed due to the pattern B2. The pattern B2 is a case where a phenomenon in which the charging voltage Ec starts to drop after the transition from the constant current region to the constant voltage region is observed. After reaching Eo of the charging characteristic of FIG. 5A, charging in the constant voltage region is started, but it is assumed that the charging voltage Ec starts to decrease and reaches point b2. By detecting this point b2, the voltage detection means 120 detects a decrease in the charging voltage Ec in the constant voltage region of the constant current constant voltage charging control (step S502 in FIG. 5 (b)).
The “thermal escape control standard 2” provided in the thermal escape detection means 150 is “when the decrease of the charging voltage Ec is detected in the constant voltage range of the constant current constant voltage charge control, the thermal escape suppression control is started”. That's it.
In response to the detection of the occurrence of thermal escape by the thermal escape detection means 150, the charging control device 140 starts “thermal escape suppression control” based on the thermal escape control reference 2 (FIG. 5 (b), step S503).

  Here, two types of “third thermal escape suppression control” and “fourth thermal escape suppression control” will be described as “thermal escape suppression control”. Either one of the processing programs may be installed in the charging control device 140, or one of them may be selected.

  An example of “third thermal escape suppression control” is to immediately stop charging the secondary battery 200 via the charging unit 110. This is the simplest process as shown in FIG.

  In the example of “fourth thermal escape suppression control”, even if the charging voltage Ec decreases, the charging is not stopped immediately, and the thermal escape due to a temporary malfunction or a temporary chemical phenomenon does not occur. For this reason, the device is devised to provide a period for continuously monitoring the charging voltage Ec while changing the charging current limit value and watching the state.

FIG. 6 shows the flow of processing when performing “fourth thermal escape control ”.
In FIG. 6, steps S501 to S503 are shown again in FIG. When “fourth thermal escape control ” is started, the charging current limit value in constant current constant voltage charging control (normal control), which is normal control, is reduced by a certain amount in order to see the situation for a while. The “current limit value updating procedure” (step S601) and the “charging voltage monitoring procedure” (step S602) for monitoring whether the charging voltage Ec in the voltage detecting unit 120 decreases thereafter are repeated, and the voltage detecting unit 120 is again used. (Step S604), and if the decrease in the charging voltage Ec is resolved, the charging of the secondary battery 200 is resumed as a temporary phenomenon. (Step S602: Y, go to Step S501) If the decrease in the charging voltage Ec is not resolved, “charging current limit value update procedure” (Step S601) is again performed. The execution of the “charging voltage monitoring procedure” (step S602) will be repeated. If the number of repetitions reaches a certain number of times (step S603: Y), it is determined that a thermal escape has occurred, and the charging control device 140 The charging of the secondary battery 200 via the charging means 110 is stopped. The number of times follows the operation standard, but for example, about three times. If a decrease in the charging voltage in the voltage detection means 120 is detected three times in succession, it can be determined that a thermal escape has occurred, not a malfunction or a temporary chemical phenomenon, and the secondary battery 200 via the charging means 110 is transferred. It is set as the process which stops charge of.
After the “third thermal escape control ” shown in FIG. 5B or the “fourth thermal escape control ” shown in FIG. 6 is executed, the charging control device 140 controls the charging means 110 to perform charging. Request processing.

Next, another example of the flow of heat escape suppression processing will be described.
FIG. 7 is a diagram (No. 5) for explaining an example of the flow of heat escape suppression processing by the rapid charging apparatus 100 with a thermal escape prevention function.

It is assumed that the charging of the secondary battery 200 to be charged by the rapid charging apparatus 100 with the thermal escape prevention function of the present invention changes from the charging curve C as shown in FIG.
Normal electrical connection between the rapid charging apparatus 100 with a thermal escape prevention function of the present invention and the secondary battery 200 is ensured, and charging of the secondary battery 200 is started (FIG. 7B, step S701). The progress of charging of the secondary battery 200 is monitored by the voltage detection means 120 and the current detection means 130.

  Here, it is assumed that the charging progresses, shifts from the constant current region to the constant voltage region, and further reaches the point c of the charging characteristics in FIG. In a state where the point c has been reached, it can be detected that the rate of decrease of the charging current Ic has become equal to or less than a predetermined value (that is, the charging current Ic has sufficiently decreased to reach the vicinity of the bottom of the charging characteristic curve) ( FIG. 7 (b) Step S702: Y).

  The “thermal escape control standard 3” provided in the thermal escape detection means 150 is “detected that the rate of decrease of the charging current Ic is equal to or lower than a predetermined value in the constant voltage range of the constant current and constant voltage charge control. And the thermal escape suppression control is started based on the relationship between this and the time zone related to detection. The time zone for detection is, for example, between the time T2 from the start time T1 of the constant voltage range to the rated charging time T3. In other words, in a time period relatively earlier than the rated charging time T3, “predict” that the heat escape will occur with the decrease rate of the charging current Ic falling below a predetermined value, and suppress the heat escape. Control is started.

In response to the detection of the occurrence of the thermal escape by the thermal escape detection means 150, the charging control device 140 starts the “thermal escape suppression control” (FIG. 7B, step S703).
Here, two kinds of “fifth thermal escape suppression control” and “sixth thermal escape suppression control” will be described as “thermal escape suppression control”. Either one of the processing programs may be installed in the charging control device 140, or one of them may be selected.

  In the example of “fifth thermal escape suppression control”, charging of the secondary battery 200 via the charging unit 110 is immediately stopped. This is the simplest process.

The example of “sixth thermal escape suppression control” does not stop charging immediately even if the rate of decrease of the charging current Ic falls below a predetermined value. The charging of the secondary battery 200 via the is stopped.
This thermal escape control standard 3 is not the actual occurrence of thermal escape, but is a stage where it is detected that thermal escape has occurred, so it does not stop immediately, but is charged for a while In consideration of the fact that charging is possible, charging is continued for a predetermined time. The predetermined time may be determined in consideration of the battery capacity and the type of battery.
FIG. 8 is a diagram (No. 6) for explaining an example of the flow of thermal escape suppression processing by the rapid charging apparatus 100 with a thermal escape prevention function. Steps S801 to S803 are the same as the example of “fifth thermal escape suppression control” shown in FIG.
In the case of the sixth thermal escape suppression control, unlike the fifth thermal escape suppression control, charging is continued for a while until a predetermined time elapses, and charging is stopped after the predetermined time elapses. That is, if it is detected that a predetermined time has elapsed (step S804: Y), the charging control device 140 stops charging the secondary battery 200 via the charging unit 110.
After the above “fifth thermal escape suppression control” or “sixth thermal escape suppression control” is executed, the charging control device 140 controls the charging means 110 and ends the charging process.

Next, another example of the flow of heat escape suppression processing will be described.
FIG. 9 is a diagram (No. 7) for explaining an example of the flow of thermal escape suppression processing by the rapid charging apparatus 100 with a thermal escape prevention function.

It is assumed that the charging of the secondary battery 200 to be charged by the rapid charging apparatus 100 with the thermal escape prevention function of the present invention shows the change of the charging curve D1 or D2 as shown in FIG. 9A.
Normal electrical connection between the rapid charging apparatus 100 with a thermal escape prevention function of the present invention and the secondary battery 200 is ensured, and charging of the secondary battery 200 is started (FIG. 9B, step S801). The progress of charging of the secondary battery 200 is monitored by the voltage detection means 120 and the current detection means 130.

Here, two patterns are shown in FIG. 9A as patterns of thermal escape. One is a case where a change in charging current is observed due to the pattern of D1. The pattern D1 is a case where the charging current does not decrease to a predetermined value even after a predetermined time has elapsed after shifting from the constant current region to the constant voltage region. Although the charging time in FIG. 9 (a) has reached a predetermined time (for example, T2 in the figure), it is detected that the charging current has not fallen sufficiently and the charging current Ic has dropped to the point d1. Suppose. By detecting this point d1, it is detected by the voltage detection means 120 that the charging current Ic is insufficiently reduced in the constant current region of the constant current / constant voltage charging control (FIG. 9B, step S902). : Y).
Another pattern is a case where a change in charging current is observed due to the pattern D2. The pattern D2 is a case where the elapsed time from the transition from the constant current region to the constant voltage region takes longer than the predetermined time until the charging current decreases to the predetermined value. In FIG. 9A, it is detected that the charging current Ic has decreased to a predetermined value, for example, d2, and the elapsed time at that time is, for example, T3. Originally, when the elapsed time T2 decreases to this d2, the delay due to the time required until this T3 can be detected. In this way, in the constant voltage region of constant current / constant voltage charging control, the voltage detecting means 120 detects that the time for the charging current Ic to drop to a predetermined value is longer than the expected rated charging time ( FIG. 9 (b) Step S902: Y).

  “Thermal escape control standard 4” provided in the thermal escape detection means 150 is “in the constant voltage range of constant current constant voltage charge control, the charging current Ic does not decrease to a predetermined value even after a predetermined time has elapsed. The thermal escape suppression control is started when it has been detected or when it is detected that the time during which the charging current Ic decreases to a predetermined value is longer than the expected rated charging time. When this condition is met, “prediction” of the occurrence of thermal escape is initiated, and thermal escape suppression control is started.

In response to the detection of the occurrence of the thermal escape by the thermal escape detection means 150, the charging control device 140 starts “thermal escape suppression control” (FIG. 9B, step S903).
Here, two types of “seventh thermal escape suppression control” and “eighth thermal escape suppression control” will be described as “thermal escape suppression control”. Either one of the processing programs may be installed in the charging control device 140, or one of them may be selected.

  In the example of “seventh thermal escape suppression control”, charging of the secondary battery 200 via the charging unit 110 is immediately stopped. This is the simplest process.

The example of “eighth thermal runaway suppression control” does not stop charging immediately even if the decrease width of the charging current Ic decreases to a predetermined value or more. This is a process for stopping the charging of the battery 200.
This thermal escape control standard 4 is a stage in which thermal escape is not actually occurring, but is detected when thermal escape occurs. Therefore, it does not stop immediately but is charged for a while. In consideration of the fact that charging is possible, charging is continued for a predetermined time. The predetermined time may be determined in consideration of the battery capacity and the type of battery.
FIG. 10 is a flowchart illustrating an example of the eighth thermal escape suppression control process.
Steps S1001 to S1003 are the same as those in the “seventh thermal escape suppression control” shown in FIG.
In the case of the eighth thermal escape suppression control, unlike the seventh thermal escape suppression control, the charging is continued for a while until a predetermined time elapses, and the charging is stopped after the predetermined time elapses. That is, if it is detected that a predetermined time has elapsed (step S1004: Y), the charging control device 140 stops charging the secondary battery 200 via the charging unit 110.
After the “seventh thermal escape suppression control” or “eighth thermal escape suppression control” is executed, the charging control device 140 controls the charging unit 110 and ends the charging process.

  As mentioned above, although preferred embodiment in the quick charging device with a thermal runaway prevention function of the present invention has been illustrated and described, it is understood that various modifications can be made without departing from the technical scope of the present invention. I will.

  The rapid charging device with a thermal escape prevention function of the present invention is applied to a charging device for charging a secondary battery, and can be widely applied without being particularly limited as long as it is a secondary battery. As an example, it will be understood that even a lithium battery, a lithium ion battery, a nickel-cadmium battery, a nickel-hydrogen metal battery, a lead storage battery, and the like can be applied.

It is a figure explaining the outline | summary of generation | occurrence | production of a thermal escape phenomenon. It is the figure which showed typically the basic composition of the rapid charging apparatus 1 with the thermal escape prevention function concerning Example 1. FIG. It is FIG. (1) explaining an example of the flow of the thermal escape suppression process by the quick charger with a thermal escape prevention function. It is FIG. (2) explaining an example of the flow of the thermal escape suppression process by the rapid charging apparatus with a thermal escape prevention function. It is FIG. (3) explaining an example of the flow of the thermal escape suppression process by the quick charging apparatus with a thermal escape prevention function. It is FIG. (4) explaining an example of the flow of the thermal escape suppression process by the rapid charging apparatus with a thermal escape prevention function. It is FIG. (5) explaining an example of the flow of the thermal escape suppression process by the quick charger with a thermal escape prevention function. It is FIG. (6) explaining an example of the flow of the thermal escape suppression process by the rapid charging apparatus with a thermal escape prevention function. It is FIG. (7) explaining an example of the flow of the thermal escape suppression process by the quick charging apparatus with a thermal escape prevention function. It is FIG. (8) explaining an example of the flow of the thermal escape suppression process by the quick charging apparatus 100 with a thermal escape prevention function. It is the figure which showed simply the outline of the charging characteristic of the time change of the secondary battery voltage in the case of charging using the constant voltage charging method in a prior art, and the time change of a charging current. It is the figure which showed simply the outline of the charge characteristic of the time change of the secondary battery voltage in the case of charging using the constant current and constant voltage charging method in a prior art, and the time change of a charging current.

DESCRIPTION OF SYMBOLS 100 Rapid charging device with thermal escape prevention function 110 Charging means 120 Voltage detection means 130 Current detection means 140 Charge control apparatus 150 Thermal escape detection means

Claims (2)

Charging means for supplying a charging voltage or charging current to the secondary battery, voltage detecting means for detecting the terminal voltage of the secondary battery, and current detecting means for detecting the current value of the charging current passed through the secondary battery And a charging control device for controlling the charging voltage or the charging current of the charging means, the charging control device using a rated voltage and a rated charging current of the secondary battery to be charged, a constant current In the quick charger that performs constant voltage charge control,
The charge control device comprises a thermal escape detection means for predicting or detecting the occurrence of thermal escape in the charged state of the secondary battery,
The charging control device is configured to detect or detect the occurrence of thermal escape by the constant current and constant voltage charging control applied to a normal time when the thermal escape detection means does not predict or detect the occurrence of the thermal escape. If equipped with thermal escape control applied by switching from the constant current constant voltage charging control,
The thermal escape control is started in a constant voltage region of the constant current constant voltage charging control by switching when the increase in the charging current is detected by the current detecting means,
The thermal escape control is a charge current limit value update procedure for reducing the charge current limit value in the constant current constant voltage charge control in the constant current region or the constant voltage region by a certain amount, and then the charging is performed again in the current detection means. A monitoring procedure for monitoring whether the current increases and a procedure for reducing the most recent charging current limit value by a certain amount in the charging current limit value updating procedure if the charging current increases again in the monitoring procedure are repeated, and the charging A rapid charging apparatus with a thermal runaway prevention function, which stops charging the secondary battery via the charging means when the current limit value update procedure is executed a predetermined number of times or more. Charging means for supplying a charging voltage or charging current to the secondary battery, voltage detecting means for detecting the terminal voltage of the secondary battery, and current detecting means for detecting the current value of the charging current passed through the secondary battery And a charging control device for controlling the charging voltage or the charging current of the charging means, the charging control device using a rated voltage and a rated charging current of the secondary battery to be charged, a constant current In the quick charger that performs constant voltage charge control,
The charge control device comprises a thermal escape detection means for predicting or detecting the occurrence of thermal escape in the charged state of the secondary battery,
The charging control device is configured to detect or detect the occurrence of thermal escape by the constant current and constant voltage charging control applied to a normal time when the thermal escape detection means does not predict or detect the occurrence of the thermal escape. If equipped with thermal escape control applied by switching from the constant current constant voltage charging control,
In the constant current region or constant voltage region of the constant current / constant voltage charging control, the thermal escape control is switched and started when the decrease in the charging voltage is detected by the voltage detecting means,
The thermal escape control is a charge current limit value update procedure for reducing the charge current limit value in the constant current constant voltage charge control in the constant voltage range by a certain amount, and then the charge voltage is reduced again in the voltage detection means. The charging current limit value update is repeated by repeating a monitoring procedure for monitoring whether or not the charging voltage is decreased again in the monitoring procedure, and the charging current limit value update procedure decreases the latest charge current limit value by a certain amount in the monitoring procedure. A rapid charging apparatus with a thermal escape prevention function, which stops charging the secondary battery via the charging means when the execution of the procedure reaches a certain number of times.

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