JP4436284B2 - Voltage equalization device for storage element - Google Patents

Description

  The present invention relates to a voltage equalization apparatus for a storage element for equalizing terminal voltages of a plurality of storage elements constituting a battery or the like.

  In general, a battery in which a large number (for example, around 100) of power storage elements are connected in series is mounted on an electric vehicle that runs by a motor or a hybrid vehicle that runs by using an engine and a motor together. The battery is connected with a voltage equalizing device that equalizes each terminal voltage of each power storage element in consideration of securing charging capacity, extending the life of each power storage element, safety, and the like.

Conventionally, this type of voltage equalizing apparatus, in particular, a type that equalizes by flowing a full-wave current that alternately repeats a positive-side half-wave current and a negative-side half-wave current, is disclosed in US Pat. An equalizing device is known. This voltage equalizing apparatus includes a transformer having a primary winding having a center tap and a plurality of secondary windings having a center tap corresponding to each power storage element. A wave current (primary current) is allowed to flow, and a secondary current is allowed to flow from each secondary winding to the corresponding storage element via a full-wave rectifier circuit.
U.S. Pat. No. 4,084,124

  However, the conventional voltage equalizing apparatus disclosed in Patent Document 1 described above uses a transformer around which a plurality of secondary windings having a center tap are wound. As a result, there is a problem in that the voltage equalizing apparatus itself is increased in size, and further increases in weight and cost.

  In particular, since the battery mounted on the above-described electric vehicle or the like is prepared by connecting a module with about 10 storage elements and further connected with about 10 modules, the battery as a whole has about 100 units. As a result, about 100 secondary windings of the transformer are required. On the other hand, when a secondary winding having a center tap is wound, the number of windings is substantially twice that of a simple winding without a center tap. In the end, the total number of turns in the secondary winding reaches a considerable amount, which is an important problem for this type of battery.

  An object of the present invention is to provide a voltage equalizing apparatus for a storage element that solves the problems existing in the background art.

  In order to solve the above-described problems, the present invention provides the primary winding 2f when configuring the voltage equalizing devices 1a and 1b for the power storage elements that equalize the terminal voltages V of the plurality of power storage elements B connected in series. And a transformer 2 having a plurality of secondary windings 2s corresponding to at least each storage element B, and a full wave that alternately repeats a positive half-wave current Ix and a negative half-wave current Iy with respect to the primary winding 2f. A power source means 3 for supplying a current Io, a first rectifying means 4 for supplying a secondary current ix corresponding to the positive half-wave current Ix to the corresponding storage elements B from the secondary windings 2s. The secondary currents iy corresponding to the negative half-wave currents Iy are passed from the secondary windings 2s (2ss) to the other power storage elements B different from the corresponding power storage elements B, respectively. One auxiliary winding 2ss having the same configuration as the secondary winding 2s is provided, And a second rectifying means 5 for supplying a secondary current iy corresponding to the negative half-wave current Iy from the auxiliary winding 2ss to the power storage element B corresponding to the adjacent secondary winding 2s. To do.

  In this case, according to a preferred aspect of the present invention, the primary side configuration is such that the primary winding 2f is constituted by the first winding 2fx and the second winding 2fy separated by the center tap 2ct, and the primary winding 2f is fed. The DC power source Ef to be turned on / off by the switch means 11 can be configured to include power source means 3 for flowing half-wave currents Ix and Iy alternately to the first winding 2fx and the second winding 2fy. As another configuration, the primary winding 2f can be configured by a simple winding without a center tap, and can be configured by including power supply means 3 for flowing a full-wave current Io to the primary winding 2f. The power supply means 3 is connected between the primary winding 2f and a DC power supply Ef that supplies power to the primary winding 2f, and is turned on / off to switch the full-wave current Io to the primary winding 2f. 12 and 13 can be configured. On the other hand, the storage elements B... Can be used for the DC power source Ef.

  According to the voltage equalizing apparatus 1 for a storage element according to the present invention having such a configuration, the following remarkable effects can be obtained.

  (1) Even if the voltage equalizing apparatus 1 of the type that flows and equalizes the full-wave current Io is provided with a transformer 2 wound with secondary windings 2s using a simple winding without a center tap. The number of turns of the secondary windings 2s is half that of the conventional voltage equalizing device in which a secondary winding having a center tap is wound, contributing to a significant reduction in size and weight of the transformer 2, which is a main component. it can. As a result, the voltage equalization apparatus 1 itself can be reduced in size, weight, and cost.

  (2) The second rectifying means 5... Includes one auxiliary winding 2 ss configured in the same manner as the secondary winding 2 s, and from this auxiliary winding 2 ss to the storage element B corresponding to the adjacent secondary winding 2 s. On the other hand, since the secondary current iy corresponding to the negative half-wave current Iy is allowed to flow, the transformer 2 as the main component is configured by a relatively easy method of substantially adding one secondary winding 2s. can do.

  (3) According to a preferred embodiment, the primary side configuration is such that the primary winding 2f is constituted by a first winding 2fx and a second winding 2fy separated by a center tap 2ct, and a direct current is supplied to the primary winding 2f. The power supply Ef is turned on / off by the switch means 11 so that the first winding 2fx and the second winding 2fy are provided with the power supply means 3 for alternately flowing half-wave currents Ix and Iy to the first winding 2fx or the primary winding 2f. Can be configured with a simple winding without a center tap, and a configuration provided with power supply means 3 for supplying a full-wave current Io to the primary winding 2f can be adopted. You can select the configuration.

  (4) When configuring the power supply means 3 according to a preferred mode, the primary winding 2f is connected to the primary winding 2f by connecting the primary winding 2f and the DC power supply Ef that supplies power to the primary winding 2f, and turning on / off. If the switch means 12 and 13 for flowing the full-wave current Io are provided, the necessary full-wave current Io can be obtained easily and reliably.

  (5) According to a preferred embodiment, if the power storage elements B... Are used for the DC power source Ef, a separate (additional) DC power source is unnecessary, which can contribute to easier implementation.

  Next, the best embodiment according to the present invention will be given and described in detail with reference to the drawings.

  First, the structure of the voltage equalizing apparatus 1 for a storage element according to this embodiment will be described with reference to FIG.

  In FIG. 1, reference numeral 21 denotes a battery, in particular, a battery mounted on an electric vehicle that runs by a motor or a hybrid vehicle that runs by using an engine and a motor together. The battery 21 is configured by connecting a plurality of power storage elements B ... in series. The power storage elements B ... use various power storage elements such as an ion battery such as a lithium ion battery and an electric double layer capacitor. can do. Each storage element B ... may be composed of one cell, or may be composed of a plurality of cells, for example, a plurality of cells formed in series connection, parallel connection, or a combination thereof. . FIG. 1 illustrates a battery 21 using four power storage elements B..., But normally, it is configured as a module by connecting about ten power storage elements B in series, and further includes 10 modules. The battery 21 is configured by connecting the front and rear in series, and a total of about 100 total storage elements B are used.

  On the other hand, the voltage equalizing apparatus 1 according to the present embodiment is connected to the battery 21. The voltage equalizing apparatus 1 shown in FIG. 1 becomes one module. The voltage equalizing apparatus 1 includes a transformer 2 having an iron core. The transformer 2 includes a primary winding 2f and a plurality (four in the example) of secondary windings 2s corresponding to the respective storage elements B ... One auxiliary winding 2ss having the same configuration as the secondary winding 2s is provided. One such auxiliary winding 2ss is added to the transformer 2, but as described above, the transformer 2 normally used for one module includes about 10 secondary windings 2s. Therefore, the added volume is about 1/10. In this way, if the secondary winding 2s... Includes one auxiliary winding 2ss that is configured in the same manner as the secondary winding 2s, the transformer 2 as the main component substantially includes the secondary winding 2s. It can be configured by a relatively easy method of adding one.

  Further, the primary winding 2 f is configured by a first winding 2 fx and a second winding 2 fy separated by a center tap 2 ct, and the center tap 2 ct is connected to the positive terminal 21 p of the battery 21. Further, the winding start terminal of the primary winding 2f is connected to the negative terminal 21n of the battery 21 via the first switch (switch element) Sx, and the winding end terminal of the primary winding 2f is the second switch (switch element) Sy. To the negative terminal 21 n of the battery 21. Reference numeral 22 denotes a control circuit that performs switching control (ON / OFF control) for the first switch Sx and the second switch Sy. The control circuit 22 outputs pulse control signals Px and Py having an oscillation frequency of about 100 kHz from the built-in pulse oscillator, and the first switch Sx and the second switch Sy are alternately switched by the pulse control signals Px and Py. ON / OFF control (see FIG. 2).

  With such a configuration on the primary side, the DC power supply Ef for supplying power to the primary winding 2f is turned on / off by the switch means 11, whereby the half-wave current Ix is alternately supplied to the first winding 2fx and the second winding 2fy. And Iy (primary current) are supplied. In this case, the DC power source Ef is also used by the battery 21 (storage element B...), And the switch means 11 is constituted by the first switch Sx and the second switch Sy. Half-wave currents Ix and Iy constitute full-wave current Io. As described above, if the storage elements B... (Battery 21) are used as the DC power supply Ef, a separate (additional) DC power supply becomes unnecessary, which can contribute to easier implementation.

  On the other hand, the winding start terminal of each secondary winding 2s... Is connected to the negative electrode side of the corresponding storage element B... And the winding end terminal of each secondary winding 2s. One rectifying means) is connected to the positive electrode side of the corresponding storage element B. Moreover, the winding start terminal of each secondary winding 2s ... is located in other each electrical storage element B ..., ie, the next (positive electrode side) via the 2nd diode (2nd rectification means) 5 ... of a forward direction. Are connected to the winding end terminals of the secondary windings 2s corresponding to the respective storage elements B. At this time, the second diode (second rectifying means) 5 connected to the winding start terminal of the secondary winding 2s corresponding to the power storage element B located on the most positive electrode side in the battery 21 is the winding end of the auxiliary winding 2ss. While being connected to the child, the winding start terminal of the auxiliary winding 2ss is connected to the positive terminal 21p.

  Next, the operation of the voltage equalizing apparatus 1 having such a configuration will be described with reference to the time chart shown in FIG. 2 and FIG.

  First, when the voltage equalizing apparatus 1 is in operation, pulse control signals Px and Py are applied from the control circuit 22 to the first switch Sx and the second switch Sy. As a result, the first switch Sx and the second switch Sy are alternately ON / OFF controlled in synchronization with the pulse control signals Px and Py, respectively. 2A and 2B show ON / OFF states (pulse control signals Px, Py) of the first switch Sx and the second switch Sy.

  Now, assume that the first switch Sx is turned on (the second switch Sy is turned off). In this case, the positive half-wave current Ix (the positive side of the full-wave current Io) flows as a primary current in the primary winding 2f (first winding 2fx) of the transformer 2. As indicated by a dotted arrow in FIG. 1, the path through which positive half-wave current Ix flows is the positive side (positive terminal 21p) of battery 21 (DC power supply Ef) → center tap 2ct of primary winding 2f → first winding. 2fx → first switch Sx → negative side (negative electrode terminal 21n) of battery 21 (DC power supply Ef). FIG. 2C shows the timing when the positive half-wave current Ix flows.

  As a result, secondary currents ix corresponding to the positive half-wave current Ix flow through the secondary windings 2s of the transformer 2. As indicated by a dotted arrow in FIG. 1, the path through which the secondary current ix (the other secondary currents ix...) Flows at this time is the winding end terminal of the secondary winding 2s → first diode 4 → storage element. The positive electrode side of B → the negative electrode side of the storage element B → the winding start terminal of the secondary winding 2s. FIG. 2E shows the timing when the secondary current ix flows.

  In this case, since all the secondary windings 2s are connected in parallel, if there is a variation between the terminal voltages V of the respective storage elements B, the storage element having the lowest terminal voltage V is provided. Secondary currents ix... Flow in a concentrated manner with respect to B, and as a result, a voltage equalizing action occurs in which the terminal voltage of the storage element B having the lowest terminal voltage V increases.

  Next, it is assumed that the second switch Sy is turned on (the first switch Sx is turned off). In this case, the negative half-wave current Iy (the negative side of the full-wave current Io) flows as a primary current in the primary winding 2f of the transformer 2. As shown by a dotted arrow in FIG. 1, the path through which the negative half-wave current Iy flows is the positive side (positive terminal 21p) of the battery 21 (DC power supply Ef) → the center tap 2ct of the primary winding 2f → the second winding. 2fy → second switch Sy → negative side (negative electrode terminal 21n) of battery 21 (DC power supply Ef). FIG. 2D shows the timing when the negative half-wave current Iy flows.

  As a result, secondary currents iy corresponding to the negative half-wave current Iy flow through the secondary windings 2s of the transformer 2. As indicated by the dotted arrow in FIG. 1, the path through which the secondary current iy (the other secondary currents iy...) Flows is different from the secondary winding 2s through which the secondary current ix flows. The winding start terminal of the other (adjacent) secondary winding 2s (the higher voltage side when viewed from the storage element B) → the positive side of the storage element B → the negative side of the storage element B → the second diode 5 → described above. This is a winding end terminal of another (neighboring) secondary winding 2s (upper voltage side when viewed from the storage element B) different from the secondary winding 2s through which the secondary current ix flows. The secondary currents iy ... flowing through the respective storage elements B ... use other (adjacent) secondary windings 2s ..., so that the storage element B located on the highest voltage side is shown in FIG. As shown, the secondary current Iy flows using the auxiliary winding 2ss. FIG. 2F shows the timing when the secondary current iy flows.

  Also in this case, since all the secondary windings 2s are connected in parallel, if there is a variation between the terminal voltages V of the respective storage elements B, the storage element B having the lowest terminal voltage V is present. Secondary current iy ... flows in a concentrated manner, and as a result, a voltage equalizing action occurs in which the terminal voltage of the storage element B having the lowest terminal voltage V rises. Therefore, the voltage equalization process for equalizing the terminal voltages V of all the storage elements B is performed by alternately repeating the charging operation of the secondary currents ix.

  According to the voltage equalizing apparatus 1 according to the present embodiment as described above, even if the voltage equalizing apparatus 1 is of a type that flows and equalizes the full-wave current Io, it uses two simple windings without a center tap. Since the transformer 2 including the secondary windings 2s is provided, the number of windings of the secondary windings 2s is half that of a conventional voltage equalizing apparatus in which a secondary winding having a center tap is wound. This contributes to a significant reduction in size and weight of the transformer 2, which is a major component. As a result, the voltage equalization apparatus 1 itself can be reduced in size, weight, and cost.

  Next, a voltage equalizing apparatus 1b according to a modified embodiment of the present invention will be described with reference to FIG.

  The basic structure of the voltage equalizing apparatus 1b shown in FIG. 3 is the same as that of the voltage equalizing apparatus 1a shown in FIG. 1, but is different in the following points. That is, the circuit configuration on the secondary side of the transformer 2 is such that the connection point of the first diodes 4 is changed to the negative side when viewed from the storage element B, and the secondary current iy flowing from the auxiliary winding 2ss is changed to the lowest voltage. It is different from flowing to the electricity storage element B located on the side.

  Further, the circuit configuration on the primary side of the transformer 2 is configured such that the primary winding 2f is a simple winding without a center tap, and a primary power supply circuit 25 (power source) that supplies a full-wave current Io to the primary winding 2f. The difference is that means 3) is provided. Therefore, the primary power supply circuit 25 incorporates a separate DC power supply and a full-wave current Io generating circuit. In addition, in FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals to clarify the configuration, and detailed description thereof is omitted.

  In the voltage equalizing apparatus 1b shown in FIG. 3, the full-wave current Io based on the positive pulse and the negative pulse shown in FIG. 3 flows from the primary power supply circuit 25, and the secondary windings 2s... Correspond to the full-wave current Io. In the auxiliary winding 2ss, secondary currents ix ... and iy ... similar to those in the embodiment shown in FIG. 1 alternately flow, and as a result, voltage equalization processing similar to that in the embodiment is performed.

  On the other hand, FIGS. 4 and 5 show modified examples related to the circuit configuration of the primary side of the transformer 2. Therefore, in FIG. 4 and FIG. 5, the secondary side circuit of the transformer 2 is not shown, but the circuit configuration shown in FIG. 1 or FIG. 3 can be used as it is for the secondary side circuit configuration.

  In FIG. 4, the primary winding 2 f is configured by a simple winding without a center tap, and power supply means 3 is provided for flowing a full-wave current Io to the primary winding 2 f. This power supply means 3 is connected between a primary winding 2f and a DC power supply Ef that feeds power to the primary winding 2f, and is turned on / off to switch means 12 that causes full-wave current Io to flow to the primary winding 2f. Prepare and configure. In FIG. 4, a first switch (switch element) S1, a second switch (switch element) S2, a third switch (switch element) S3 and a fourth switch (switch element) S4 constitute the switch means 12, and each switch S1 -S4 is ON / OFF controlled by the control circuit 27. In addition, in FIG. 4, the same components as those in FIGS. 1 and 3 are denoted by the same reference numerals to clarify the configuration, and detailed description thereof is omitted.

  In the modification shown in FIG. 4, a so-called full bridge is configured by four switches S1 to S4, and the first switch S1 and the fourth switch S4, and the second switch S2 and the third switch S3 are turned on in synchronization with each other. The (first switch S1 and fourth switch S4) and (second switch S2 and third switch S3) are alternately ON / OFF controlled. As a result, the full-wave current Io, that is, the positive half-wave current Ix and the negative half-wave current Iy similar to those in the embodiment shown in FIG.

  In FIG. 5 also, the primary winding 2f is constituted by a simple winding without a center tap, and the power supply means 3 for supplying a full-wave current Io to the primary winding 2f is provided. This power supply means 3 is connected between the primary winding 2f and a DC power supply Ef that feeds power to the primary winding 2f, and is turned on / off to switch means 13 that causes the full-wave current Io to flow to the primary winding 2f. Prepare and configure. In FIG. 5, a first switch (switch element) Sm and a second switch (switch element) Sn constitute switch means 13, and each switch Sm and Sn is ON / OFF controlled by a control circuit 28. Cm and Cn indicate power storage units using capacitors. In addition, in FIG. 5, the same components as those in FIGS. 1 and 3 are denoted by the same reference numerals to clarify the configuration, and detailed description thereof is omitted.

  In the modification shown in FIG. 5, a so-called half bridge is constituted by two switches Sm and Sn, and the first switch Sm and the second switch Sn are alternately turned ON / OFF. As a result, the full-wave current Io, that is, the positive half-wave current Ix and the negative half-wave current Iy similar to those in the embodiment shown in FIG. In this case, since the first switch Sm and the second switch Sn are turned on / off, the power storage units Cm and Cn are repeatedly charged / discharged. Therefore, the positive half-wave current Ix includes the discharge of the power storage unit Cm. The current Im is included, and the negative half-wave current Iy includes the discharge current In of the power storage unit Cn.

  When the power supply means 3 is configured as in such a modification, it is connected between the primary winding 2f and the DC power supply Ef that feeds power to the primary winding 2f, and is turned on / off to turn off the primary winding 2f. If the switch means 12 and 13 for supplying the full-wave current Io are provided, the necessary full-wave current Io can be obtained easily and reliably. Moreover, since the structure of the primary side with respect to the transformer 2 can employ | adopt various structures, the optimal circuit structure according to a use, the objective, etc. can be selected.

  Although the best embodiment (modified embodiment) has been described in detail above, the present invention is not limited to such an embodiment, and the present invention is not limited to such a detailed circuit configuration, parts, quantity, numerical value, and the like. Any change, addition, or deletion can be made without departing from the scope of the above.

  For example, although the case where the first rectifying means 4... And the second rectifying means 5 are diodes is exemplified, transistors may be used. In this case, when one transistor is turned on, the other transistor may be turned off. Thus, the first rectifying means 4... And the second rectifying means 5... Can be replaced by other components or circuits that can exhibit the same function as when diodes are used. Further, the power supply means 3 is not limited to the example, and can be replaced by the power supply means 3 having various configurations capable of flowing the full-wave current Io, and the power supply means 3 (DC power supply Ef) Both the case where the elements B... Are used directly and the case where a separate DC power source is used are included. In addition, although the battery 21 mounted in an electric vehicle or a hybrid vehicle was illustrated as an object to which the voltage equalizing apparatuses 1a and 1b are connected, various applications in the case of including a plurality of power storage elements can be targeted.

1 is a circuit diagram of a voltage equalizing apparatus according to the best embodiment of the present invention; A time chart of signals in each part of the voltage equalizing device, A circuit diagram of a voltage equalizing apparatus according to a modified embodiment of the present invention, The circuit diagram which shows the example of a change of the circuit structure in the primary side used for the voltage equalization apparatus which concerns on this invention, The circuit diagram which shows the other example of a change of the circuit structure in the primary side used for the voltage equalization apparatus,

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Voltage equalization apparatus 1b Voltage equalization apparatus 2 Transformer 2f Primary winding 2s ... Secondary winding 2ss Auxiliary winding 2ct Center tap 2fx First winding 2fy Second winding 3 Power supply means 4 ... First rectification means 5 ... Second rectification means 11 Switch means 12 Switch means 13 Switch means Io Full wave current Ix Positive half wave current Iy Negative half wave current ix ... Secondary current iy ... Secondary current B ... Power storage element V ... Terminal voltage Ef DC power supply

Claims (5)

  In a voltage equalizing apparatus for a power storage element that equalizes each terminal voltage of a plurality of power storage elements connected in series, a transformer having a primary winding and a plurality of secondary windings corresponding to at least each power storage element, and the primary winding Power supply means for passing a full-wave current that alternately repeats a positive-side half-wave current and a negative-side half-wave current, and corresponding to the positive-side half-wave current for each storage element corresponding to each secondary winding While flowing a secondary current corresponding to the negative half-wave current to each of the other storage elements different from the respective storage elements corresponding to the first rectification means for flowing the secondary current, One auxiliary winding having the same configuration as the secondary winding is provided, and a secondary current corresponding to the negative half-wave current is supplied from the auxiliary winding to the storage element corresponding to the adjacent secondary winding. And a second rectifying means for flowing the voltage equalizing the power storage element, Apparatus.   The primary winding is composed of a first winding and a second winding separated by a center tap, and the first winding is turned on and off by a switch means with a DC power supply for supplying power to the primary winding. 2. The voltage equalizing apparatus for an electric storage element according to claim 1, further comprising power supply means for alternately supplying a half-wave current to the second winding.   2. The voltage equalization of the electric storage element according to claim 1, wherein the primary winding is configured by a simple winding without a center tap, and further includes power supply means for flowing the full-wave current to the primary winding. Device.   The power supply means is connected between the primary winding and a DC power supply that supplies power to the primary winding, and includes a switch means that causes the full-wave current to flow to the primary winding by being turned ON / OFF. The voltage equalization apparatus for a storage element according to claim 3.   5. The voltage equalization apparatus for a storage element according to claim 2, wherein the DC power source uses the storage element.

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