JP6160355B2 - Storage battery self-heating device, storage battery self-heating method and power supply system - Google Patents

Description

  The present invention relates to a self-heating device for a storage battery and a self-heating method for a storage battery when the storage battery in a power supply system needs to be heated or kept warm.

  In the molten salt battery, a molten salt is used as an electrolyte (see, for example, Patent Document 1). As the molten salt, for example, a mixture of NaFSA (sodium bisfluorosulfonylamide) and KFSA (potassium bisfluorosulfonylamide) is used, and the melting point is about 57 degrees. However, 90 ° C. or higher is preferable for stable operation. Therefore, in order to provide such a temperature environment, a heater is provided on the outer surface of the battery container, and the electrolyte (electrolyte) is raised from the outside to a desired temperature by the heater heating and maintained.

  Further, NaS (sodium-sulfur) batteries require higher temperatures. Therefore, a large electric power is required for the heater. In view of this, it is considered to use the self-heating of the NaS battery itself in order to reduce the power for heating and heat retention as much as possible (see, for example, Patent Document 2). In this case, for example, charging / discharging is performed between the grid power and the NaS battery, and the self-generated heat of the NaS battery at that time is used for heating / warming. In addition, a technique for heating and keeping warm of a storage battery using self-heating has been proposed (for example, see Patent Document 3).

JP 2012-190543 A JP-A-8-17474 JP 2011-18531 A

However, heating by the heater causes a loss of electric power when energy is converted from electricity to heat. Also, heat loss occurs when conducting heat from the heater to the battery container. Furthermore, for example, a molten salt battery is configured to obtain a desired output by arranging a large number of single cells housed in a battery container to form an assembled battery, and connecting each battery in series or series-parallel. In this case, it is difficult for the heater to uniformly apply heat to all the battery containers, resulting in temperature variations.
Even if the self-heating of the storage battery is used, it is difficult to obtain a sufficient amount of heat generation because the internal resistance is small.

  In view of such conventional problems, an object of the present invention is to provide a new heating / warming technique for a storage battery that requires heating / warming.

The present specification discloses the following inventions. However, the present invention is defined by the description of the scope of claims. For example, this device includes a chargeable / dischargeable storage battery, a temperature sensor that detects the temperature of the storage battery, and a power converter that is connected to the storage battery and that is related to the discharge of the storage battery. When it is determined that it is necessary to increase the heat generation amount of the storage battery based on the detection output of the temperature sensor, the discharge current output from the storage battery is changed to a pulse train, and the larger the necessary heat generation amount, the more the storage battery This is a self-heating device for a storage battery that increases the pulse and narrows the pulse width within the range up to the allowable upper limit value. It is also a power supply system including such a self-heating device.

  In the self-heating method of the storage battery of the present invention, the temperature of the chargeable / dischargeable storage battery is detected by a temperature sensor, and the power converter connected to the storage battery is connected to the detection output of the temperature sensor. Based on this, when it is determined that the amount of heat generated by the storage battery needs to be increased, the discharge current of the storage battery is changed to a pulse train, and the larger the required amount of heat generation, the more the range up to the allowable upper limit value of the storage battery. The pulse is made high and the pulse width is made narrow.

  According to the present invention, since heat is generated from the inside of the storage battery, the storage battery can be efficiently heated or kept warm. In addition, when the storage battery is an assembled battery in which unit batteries are assembled, there is less heating unevenness and waste than an external heating device such as a heater, and as a result, the heat insulation structure of the outer casing of the assembled battery is simplified. Can do.

1 is a connection diagram showing a self-supporting power supply system including a self-heating device for a storage battery according to an embodiment of the present invention. It is a figure which shows the equivalent circuit inside a storage battery. It is a figure which shows the relationship between the temperature range of a storage battery, and discharge current. It is a flowchart which shows an example of control of the discharge current / charging current of a storage battery performed by a DC / DC converter. It is a connection diagram which shows the self-heating apparatus of the storage battery which concerns on other embodiment.

<< Summary of Embodiment >>
The gist of the embodiment of the present invention includes at least the following.

  (1) A self-heating device for the storage battery includes a chargeable / dischargeable storage battery, a temperature sensor that detects a temperature of the storage battery, and a power converter that is connected to the storage battery and is associated with the discharge of the storage battery, When it is determined that the power converter needs to increase the heat generation amount of the storage battery based on the detection output of the temperature sensor, the power converter converts the discharge current output from the storage battery into a pulse train and the required heat generation amount The larger the is, the higher the pulse is within the range up to the allowable upper limit value of the storage battery, and the narrower the pulse width.

  In the self-heating device of the storage battery configured as described above, when the power converter determines that the heat generation amount of the storage battery needs to be increased for the purpose of temperature increase or heat retention, the discharge current output from the storage battery is converted into a pulse train. To. By controlling the pulse height and pulse width in this pulse train, the necessary heat generation amount can be obtained by the heat generation from the internal resistance of the storage battery. That is, by controlling the pulse height and pulse width, it is possible to change the heat generation amount even with the same coulomb amount as compared with a continuous current. Specifically, the larger the required amount of heat generation, the higher the pulse and the narrower the pulse width. In other words, the smaller the required amount of heat generation, the lower the pulse and the wider the pulse width. Since such heat is generated from the inside of the storage battery, the storage battery can be efficiently heated or kept warm. In addition, when the storage battery is an assembled battery in which unit batteries are assembled, there is less heating unevenness and waste than an external heating device such as a heater, and as a result, the heat insulation structure of the outer casing of the assembled battery is simplified. Can do.

(2) In the self-heating device of (1), the power converter is also involved in charging the storage battery, and it is determined that the heat generation amount of the storage battery needs to be increased based on the detection output of the temperature sensor. In this case, the current for charging the storage battery may be a pulse train, and the larger the required amount of heat generation, the higher the pulse within the range up to the allowable upper limit value and the narrower the pulse width. .
In this case, the required amount of heat generation can be obtained by heat generation from the internal resistance of the storage battery during charging as well as during discharging.

(3) Also, in the self-heating device of (1) or (2), k is a number greater than 1 and the current is a pulse train on the basis that the current I flows to the storage battery continuously over a unit time t. If the margin time considering the voltage drop of the storage battery due to is α, the pulse height I _h is I _h = k · I, and the pulse width Δt is Δt = (t / k) + α. preferable.
In this case, as a result, the coulomb amount (P = I · t = kI · (t / k)) when α is neglected even when the heat generation amount is changed and the pulse train is changed is as follows. It can be the same value.

(4) Moreover, in the self-heating device of (1) to (3), a plurality of sets of the storage battery, the temperature sensor, and the power converter are provided under a common power supply path, and discharge of one set of storage batteries is performed. Thus, another set of storage batteries may be charged.
In this case, the temperature can be raised or kept between the storage batteries without depending on the load or other power source.

  (5) On the other hand, as a self-heating method of the storage battery, the temperature of the chargeable / dischargeable storage battery is detected by a temperature sensor, and the power converter connected to the storage battery and discharging the storage battery is detected by the temperature sensor. If it is determined that it is necessary to increase the amount of heat generated by the storage battery, the discharge current of the storage battery is changed to a pulse train, and the larger the required amount of heat generated, the more the range up to the allowable upper limit value of the storage battery. The pulse is increased and the pulse width is decreased.

  In the self-heating method of the storage battery as described in (5) above, the discharge current output from the storage battery is used as a pulse train, and the required heat generation amount is reduced by controlling the pulse height and pulse width in this pulse train. It can be obtained by heat generation from the internal resistance. That is, by controlling the pulse height and pulse width, it is possible to change the heat generation amount even with the same coulomb amount as compared with a continuous current. Specifically, the larger the required amount of heat generation, the higher the pulse and the narrower the pulse width. In other words, the smaller the required amount of heat generation, the lower the pulse and the wider the pulse width. Since such heat is generated from the inside of the storage battery, the storage battery can be efficiently heated or kept warm. In addition, when the storage battery is an assembled battery in which unit batteries are assembled, there is less heating unevenness and waste than an external heating device such as a heater, and as a result, the heat insulation structure of the outer casing of the assembled battery is simplified. Can do.

(6) Moreover, in the self-heating method of (5), it is determined that the power converter needs to increase the amount of heat generated by the storage battery based on the detection output of the temperature sensor in connection with charging of the storage battery. In this case, the current for charging the storage battery may be a pulse train, and the larger the required amount of heat generated, the higher the pulse within the range up to the allowable upper limit value and the narrower the pulse width.
In this case, the required amount of heat generation can be obtained by heat generation from the internal resistance of the storage battery during charging as well as during discharging.

(7) Further, in the self-heating method of (5) or (6), the deterioration rate of the storage battery is diagnosed by comparing the rate of temperature rise of the storage battery when a constant current of the pulse train is passed with a threshold value. Is also possible.
In this case, the self-heating device can also have a storage battery deterioration diagnosis function.

  (8) Moreover, the self-heating device of the storage battery of (1) can be included as a part of the power supply system. Such a power supply system can efficiently heat or keep the storage battery warm.

<< Details of Embodiment >>
(First embodiment)
FIG. 1 is a connection diagram showing a self-supporting power supply system 100 including a storage battery self-heating device according to an embodiment of the present invention. The power supply system 100 includes a photovoltaic power generation panel 1, a DC / DC converter 2, a bidirectional DC / DC converter 3, a storage battery 4, and an inverter 5, which are connected as illustrated. ing. The output of the photovoltaic power generation panel 1 is converted into a predetermined voltage by the DC / DC converter 2. Further, the DC / DC converter 2 performs MPPT (Maximum Power Point Tracking) control and draws the maximum power from the photovoltaic power generation panel 1. The output of the DC / DC converter 2 is connected to the DC bus Bdc. Power can be supplied directly to the DC load 6 from the DC bus Bdc. Further, by converting the voltage of the DC bus Bdc into alternating current by the inverter 5, electric power can be supplied to the alternating current load 7.

  The DC / DC converter 3 converts the voltage of the DC bus Bdc into a voltage suitable for charging the storage battery 4 and charges the storage battery 4. The storage battery 4 is a molten salt battery using, for example, a mixture of 56 mol% NaFSA (sodium bisfluorosulfonylamide) and 44 mol% KFSA (potassium bisfluorosulfonylamide) as an electrolyte. The melting point of this electrolyte is 57 ° C. At a temperature equal to or higher than the melting point, the electrolyte is melted to form an electrolytic solution in which a high concentration of ions is dissolved.

  As the molten salt, in addition to the above, a mixture of NaFSA and LiFSA, KFSA and CsFSA is also suitable. In addition, other salts may be mixed (organic cation or the like). Generally, the molten salt includes (a) a mixture containing NaFSA, (b) a mixture containing NaTFSA (sodium bistrifluoromethylsulfonylamide), ( c) Mixtures containing NaFTA (sodium fluorosulfonyl-trifluoromethylsulfonylamide) are suitable.

  The storage battery 4 is in a state where the electrolyte is solidified at a temperature lower than the melting point and does not operate as a battery (a state where charging / discharging is not possible). Therefore, it is necessary to always maintain the storage battery 4 at a temperature higher than the melting point. Moreover, it is preferable to maintain the temperature at about 90 ° C. for stable operation. In the initial stage of operation of the power supply system 100, the storage battery 4 is set to the above-described preferable temperature (about 90 ° C.) using a heater (not shown). Is maintained (details will be described later).

For example, at night when the solar power generation panel 1 does not generate power, the DC / DC converter 3 converts the output voltage of the storage battery 4 into a voltage and provides it to the DC bus Bdc. Thereby, electric power can be supplied to the AC load 7 via the DC load 6 and the inverter 5, respectively.
A temperature sensor 8 is attached to the storage battery 4, and an output (temperature detection signal) of the temperature sensor 8 is sent to the DC / DC converter 3. The storage battery 4, the temperature sensor 8, and the DC / DC converter 3 constitute a storage battery self-heating device 10.

Next, the operation of the storage battery self-heating device 10 and a method for maintaining the temperature of the storage battery 4 thereby will be described.
FIG. 2 is a diagram showing an equivalent circuit inside the storage battery 4. The storage battery 4 is actually an assembly of a plurality of unit cells (for example, a plurality of unit cells connected in series and parallel), but is shown here in a simplified manner. That is, the storage battery 4 can be expressed as a series body of a battery 4a in a narrow sense having an electromotive force E [V] and an internal resistance 4b having a resistance value R. During charging, current flows into the battery 4a via the internal resistance 4b, and during discharging, current flows out of the battery 4a via the internal resistance 4b. The amount of heat generation W [J] due to the current I [A] flowing through the internal resistance 4b having the resistance value R [Ω] is t [sec]
W = R · I ² · t
It is represented by

  FIG. 3 is a diagram showing the relationship between the temperature region of the storage battery 4 and the discharge current. In the figure, the storage battery 4 has an operating temperature range of 57 ° C. to 190 ° C., for example, and temperatures below 57 ° C. and above 190 ° C. are unusable regions. The operating temperature region can be divided into three regions, for example, in order from the bottom, a temperature rising region that needs to be further increased, an appropriate temperature region that should maintain the current temperature, and a temperature decreasing region that is preferable to lower the temperature It is.

  For example, the current required for the storage battery 4 that discharges to the load is I [A] (current in FIG. 3A). Here, if the unit time is t [sec], the coulomb amount P [C] is P = I · t. This current I is a continuous value. Here, consider that the current is not a continuous value but a pulse train. Assuming that the unit time t is one cycle, a half time (1/2) t is a pulse width, and a pulse height, that is, a current value is 2I (current in FIG. 3B). The coulomb amount in this case is P = 2I · (1/2) t = I · t, and the coulomb amount is the same as in the case of (a).

Further, a time (1/4) t that is ¼ of the unit time t is set as a pulse width, and a current value is set as 4I (current in FIG. 3C). The coulomb amount in this case is P = 4I · (1/4) t = I · t, and the coulomb amount is the same as in the case of (a). Furthermore, as a general formula, if the height of the pulse, that is, the magnitude of the current is k times the current I at the continuous value shown in (a) (k> 1), P = kI · (1 / k) t = I · t, and the coulomb amount is the same as in the case of (a).
That is, even if the discharge current is converted into a pulse train, if the pulse height is changed according to the pulse width, the same coulomb amount can be provided, and necessary power can be supplied to the load. However, the height of the pulse is set so as not to exceed the allowable upper limit value I _max of the discharge current of the storage battery 4.

On the other hand, the calorific value W [J] per unit time due to the internal resistance 4b of the storage battery 4 is the current (a):
W = R · I ² t (1)
It is.
On the other hand, when the current is (b),
W = R · (2I) ² · (t / 2) = 2R · I ² t (2)
It is.
Furthermore, when the current of (c) is
W = R · (4I) ² · (t / 4) = 4R · I ² t (3)
It is.
To obtain a general formula, the above-mentioned k is used,
W = R · (kI) ² · (t / k) = kR · I ² t (4)
It is. However, kI ≦ I _max must be satisfied.

From the above equations (2), (3), and (4), it can be seen that even if the coulomb amount P is unchanged, the amount of heat generated can be changed by using a pulse train. Further, by controlling the pulse height and the pulse width, a necessary heat generation amount can be obtained by the heat generation from the internal resistance 4 b of the storage battery 4.
The above is the basic idea, but actually, the voltage of the storage battery 4 slightly decreases (IR drop) when the current of the storage battery 4 becomes a pulse train. The degree of this reduction varies depending on the storage battery. Therefore, in order to set the power supplied to the load to a desired constant value, it is necessary to slightly increase the pulse width with a margin. In other words, the margin time considering the voltage drop of the storage battery 4 due to the pulse train of current is α [seconds], and k is greater than 1 on the basis that the current I flows to the storage battery 4 continuously over a unit time t. Assuming a number, the pulse height I _h is I _h = k · I, and the pulse width Δt is Δt = (t / k) + α.

The discharge current in the form of a pulse train as described above is realized by the DC / DC converter 3 performing step-up chopper control on the output current from the storage battery 4.
Moreover, although the above description has been described with respect to the discharge current, the same applies to the charging current. In that case, the DC / DC converter 3 outputs a pulse train-like current, thereby realizing a pulse train-like charging current.
The frequency of the pulse train is, for example, several hertz, that is, about several pulses per second. Although a smoothing capacitor (not shown) is built in the DC / DC converter 3, the waveform of the pulse train is hardly dulled by smoothing at such a low frequency.

FIG. 4 is a flowchart showing an example of control of the discharge current / charge current of the storage battery 4 executed by the DC / DC converter 3. When the process of this flowchart is started, the storage battery 4 is already in operation. First, in step S1, the DC / DC converter 3 determines whether or not the storage battery 4 is in the temperature rising region based on the temperature detection signal. When it is in the temperature rising range, that is, when it is determined that the calorific value of the storage battery 4 needs to be particularly increased, the DC / DC converter 3 makes the current a pulse train and, for example, sets the pulse height _Ih to I _{It is} assumed that _h = 4I and the pulse width Δt is Δt = (t / 4) + α (step S2).

When I _h exceeds the allowable upper limit value I _max , it is necessary to limit to I _h = I _max and set the pulse width to a value corresponding thereto. The allowable upper limit value I _max varies depending on the type of storage battery, battery capacity, temperature, and the like. Since the DC / DC converter 3 knows the temperature of the storage battery 4 and is directly connected to the storage battery 4, the battery capacity can be estimated from OCV (Open Circuit Voltage). Accordingly, DC / DC converter 3 is an allowable upper limit _{I max,} it is possible to dynamically grasp. In addition, the allowable upper limit value I _max can be set as a fixed value in advance.

Further, when the temperature is not in the temperature rising range in step S1, the DC / DC converter 3 determines in step S3 whether or not the storage battery 4 is in the proper temperature range. When it is in the proper temperature range, that is, when it is determined that the calorific value of the storage battery 4 needs to be increased, the DC / DC converter 3 converts the current into a pulse train and, for example, sets the pulse height I _h to I _h = 2I. The pulse width Δt is set to Δt = (t / 2) + α (step S4).

When the temperature is not in the proper temperature range in step S3, the DC / DC converter 3 determines in step S5 whether or not the storage battery 4 is in the temperature decrease range. If the temperature falls, the DC / DC converter 3 sets the current to a continuous value (step S6).
In step S5, if it is not the temperature-decreasing region, it is an unusable region that is not one of the temperature-raising region, the appropriate temperature region, and the temperature-decreasing region, and the process ends.

  As described above in detail, in the self-heating device 10 of the storage battery, the DC / DC converter 3 outputs from the storage battery 4 when it is determined that the heat generation amount of the storage battery 4 needs to be increased for the purpose of temperature increase or heat retention. The discharge current (or the charging current input to the storage battery 4) is converted into a pulse train. By controlling the pulse height and pulse width in this pulse train, the necessary heat generation can be obtained by the heat generation from the internal resistance 4 b of the storage battery 4. By controlling the height and width of the pulse, it is possible to change the amount of heat generated even with the same coulomb amount as compared with a continuous current. The larger the required amount of heat generation, the higher the pulse and the narrower the pulse width. In other words, the smaller the required amount of heat generation, the lower the pulse and the wider the pulse width.

Since such heat is generated from the inside of the battery container of the storage battery 4, the storage battery 4 can be efficiently heated or kept warm. Further, when the storage battery 4 is an assembled battery in which unit batteries are assembled, if an external heating device such as a heater is used, uneven heating is likely to occur, and waste due to part of the heat escaping to the outside occurs. Therefore, it is necessary to have an outer box having a sufficient heat insulation structure so that heat does not escape as much as possible and is uniform inside, but in the case of heat generation due to the above internal resistance, Since it heats from inside, the heat insulation structure of an outer box can be simplified.
Moreover, the power supply system 100 including such a self-heating device 10 can efficiently raise or keep the temperature of the storage battery 4.

  Further, the deterioration of the storage battery 4 is related to the resistance value of the internal resistance 4b, and the resistance value increases as the deterioration progresses. Therefore, the deterioration diagnosis can be performed by comparing with the threshold value from the rate of temperature rise of the storage battery 4 when the constant current of the pulse train is passed.

(Second Embodiment)
FIG. 5 is a connection diagram illustrating a self-heating device for a storage battery according to another embodiment. In the figure, for example, two power converters 9 and a storage battery 4 are provided under one power system. The power converter 9 is bidirectional, and becomes a rectifier when charging the storage battery 4, and becomes an inverter when discharging from the storage battery 4. The storage battery 4 is provided with a temperature sensor 8. The left storage battery 4, the temperature sensor 8, and the power converter 9 constitute a self-heating device 10A of the storage battery. Similarly, the right storage battery 4, the temperature sensor 8, and the power converter 9 constitute a storage battery self-heating device 10B.

In the configuration as shown in FIG. 5, the other set of storage batteries 4 can be charged by discharging one set of storage batteries 4. Therefore, even when energy is not supplied to the load or charging energy is not received from the power system, energy is exchanged between the storage battery 4 groups by discharging and charging, and the storage battery 4 is actively used. Can generate heat.
In this case, although there is a slight power loss due to passing two power converters 9, there is an advantage that the temperature can be raised or kept between the storage batteries 4 without depending on the load or other power source. is there.
Moreover, although FIG. 5 is an example of 2 sets, it is also possible to self-heat a storage battery by exchanging energy mutually in 3 or more sets.

(Other)
In FIG. 1, a self-supporting power supply system 100 is illustrated. This is a suitable example in which the self-heating device 10 for a storage battery is applied in that the generated power is limited. However, even in a power supply system using a commercial power supply in combination, it is possible to realize further power saving by applying the storage battery self-heating device 10 as described above.

In addition, although each said embodiment mentioned the molten salt battery as the storage battery 4, when using it in a cold district also in a lithium ion battery, in order to fully demonstrate performance, a heating may be required, Even in such a case, the above-described self-heating device for a storage battery can be applied.
The above-described self-heating device for a storage battery can also be applied to a NaS (sodium sulfur) battery that is used at a higher temperature than a molten salt battery.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Photovoltaic power generation panel 2 DC / DC converter 3 DC / DC converter 4 Storage battery 4a Battery 4b Internal resistance 5 Inverter 6 DC load 7 AC load 8 Temperature sensor 9 Power converter 10, 10A, 10B Self-heating device of storage battery 100 Power supply system

Claims (6)

A rechargeable storage battery;
A temperature sensor for detecting the temperature of the storage battery;
A power converter connected to the storage battery and involved in discharging the storage battery,
The power converter determines, based on the detection output of the temperature sensor, that it is necessary to control the discharge current output from the storage battery from continuous to discontinuous or vice versa and to increase the calorific value of the storage battery. In this case, the discharge current output from the storage battery is a discontinuous DC pulse train, and the larger the required amount of heat generation, the higher the pulse within the range up to the allowable upper limit of the storage battery, and the pulse width. narrowly, based on the current I flowing to the battery in a continuous value for the unit time t, k a number greater than 1, when the margin time in consideration of the voltage drop of the battery due to the current pulse train and α The self-heating device of the storage battery , wherein the pulse height I _h is I _h = k · I, and the pulse width Δt is Δt = (t / k) + α . The power converter is also involved in the charging of the storage battery, and based on the detection output of the temperature sensor, the charging current input to the storage battery is controlled from continuous to discontinuous or vice versa, thereby increasing the amount of heat generated by the storage battery. If it is determined that it is necessary to make the current to charge the storage battery into a discontinuous DC pulse train, the larger the required amount of heat generation, the higher the pulse within the range up to the allowable upper limit, and The self-heating device for a storage battery according to claim 1, wherein the pulse width is narrowed. The said storage battery, the said temperature sensor, and the said power converter are provided in multiple sets under the common electric power feeding path, and charge the other set of storage batteries by discharge of one set of storage batteries. The storage battery self-heating device described. The temperature of the rechargeable storage battery is detected by a temperature sensor,
The power converter connected to the storage battery and related to the discharge of the storage battery controls the discharge current output from the storage battery from continuous to discontinuous or vice versa based on the detection output of the temperature sensor. When it is determined that the amount of heat generation needs to be increased, the discharge current of the storage battery is changed to a discontinuous DC pulse train, and the larger the required amount of heat generation, the more the pulse is within the range up to the allowable upper limit value of the storage battery. , And the pulse width is narrowed, and the voltage drop of the storage battery due to a current greater than 1 and the current being a pulse train is defined as the current I flowing to the storage battery continuously over a unit time t. The self-heating method of the storage battery , where the pulse height I _h is I _h = k · I, and the pulse width Δt is Δt = (t / k) + α, where α is the considered margin time . The power converter is also involved in the charging of the storage battery, and based on the detection output of the temperature sensor, the charging current input to the storage battery is controlled from continuous to discontinuous or vice versa, thereby increasing the amount of heat generated by the storage battery. If it is determined that it is necessary to make the current to charge the storage battery into a discontinuous DC pulse train, the larger the required amount of heat generation, the higher the pulse within the range up to the allowable upper limit, and The self-heating method of a storage battery according to claim 4 , wherein the pulse width is narrowed. A power supply system including the storage battery self-heating device according to claim 1 .

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