JP2008035680A - Multi-series storage cell - Google Patents

Abstract

In a multi-series storage cell having a large number of series connections, voltage balance correction of all cells can be performed quickly and smoothly while improving workability such as assembly and replacement.
The multi-series storage cells (B1 to Bn) are divided into a plurality of series cell groups (G1, G2,...) That are continuous in the connection order, and the voltage balance between adjacent cells in each cell group. A group for correcting the inter-cell voltage balance correction circuit 31 for performing correction and correcting the balance of the series voltage of each cell group by AC coupling formed by using the transformer coil (L1, L2,...) And the switching circuit Sc. An inter-voltage balance correction circuit 32 is provided.
[Selection] Figure 1

Description

  The present invention relates to a multi-series storage cell including a plurality of storage cells connected in series and a voltage balance correction circuit that equalizes the voltage of each cell.

  In many cases, a large number of storage cells such as capacitors and secondary batteries are connected in series. In this case, when voltage variation occurs between cells, there is a problem that the life of the cell is shortened due to the concentration of voltage in a specific cell. This problem becomes more prominent as the number of series connections increases. Therefore, when the storage cells are connected in series, the voltages of the cells need to be balanced (equalized) with each other.

  As a circuit for performing this voltage balance correction, an inductor coupling system illustrated in FIG. 7 and a transformer coupling system illustrated in FIG. 8 are known (see, for example, Patent Documents 1 to 3).

  As shown in FIG. 7, the inductor-coupled voltage balance correction circuit balances the voltages of the cells 11 with each other using an inductor Lc and switching elements Sa and Sb. That is, by charging and discharging the inductor current between adjacent B1 and B2, B2 and B3,..., Bn-1 and Bn, the voltage between both cells is balanced to the same voltage.

  For this reason, an inductor Lc is installed between each cell 11. At the same time, switching circuits Sa and Sb for alternately connecting the inductors Lc to the first cell and the second cell are provided.

  As shown in FIG. 8, the transformer-coupled voltage balance correction circuit includes a plurality of transformer coils L1 to Ln that form a one-to-one transformation ratio and a switching circuit Sc that operates on and off in phase with each other. The cells 11 (B1 to Bn) are AC coupled (AC coupled) to each other. Thereby, the voltage of each cell 11 (B1-Bn) is balance-corrected to the same voltage.

The multi-series storage cell in which the voltage balance of each cell is corrected as described above is a power generation / load device such as an electric motor in which the series terminals P1 and P2 of all the cells (B1 to Bn) serve as power for the electric vehicle, for example. 100 is used by being connected.
JP 2001-185229 A JP 2006-67742 A JP 2004-201361 (paragraph 0046)

  The conventional multi-series energy storage cell described above is effective when the number of series connections is not so large, but the following problems become apparent when the number of series connections increases.

  For example, in motive power sources for electric vehicles or power storage systems for load leveling, tens to hundreds of power storage cells are often connected in series. Also in this case, it is necessary to perform balance correction of each cell voltage.

  When the number of series connections is large, the inductor-coupled voltage balance correction circuit shown in FIG. 7 can quickly and smoothly perform balance correction between adjacent cells, but the balance correction for all cells is completed. It takes time. This is because it is necessary to wait for the effect of the balance correction performed locally between adjacent cells to be sequentially transmitted cell by cell to reach all cells (B1 to Bn).

  On the other hand, in the transformer-coupled voltage balance correction circuit shown in FIG. 8, all the cells (B1 to Bn) are AC-coupled to each other via a transformer coil (L1 to Ln) having a 1: 1 transformation ratio. Balance correction for all cells can be performed simultaneously.

  However, the number of coils of the transformer T1 is limited, and the number of coils that can be wound around the same magnetic core 21 is about ten to several tens. For this reason, the transformer-coupled voltage balance correction circuit cannot be applied to a multi-series storage cell in which the number of series connections exceeds 100, for example.

  In addition, when the number of series connection of the storage cells increases, the number of wirings between the transformer T1 and the cell row (B1 to Bn) increases, and the workability of assembling or replacing the multi-series storage cells is significantly hindered. Occurs.

  The present invention has been made in view of the technical background as described above, and its purpose is to improve the workability of assembly and replacement in a multi-series storage cell having a large number of series connections, while maintaining the voltage balance of all cells. An object of the present invention is to provide a multi-series energy storage cell that enables correction to be performed quickly and smoothly.

  Other objects and configurations of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  The solution provided by the present invention is as follows.

  (1) A multi-series energy storage cell including a plurality of energy storage cells connected in series and a voltage balance correction circuit for equalizing the voltage of each cell, wherein the plurality of energy storage cells are connected in series in the order of connection. Each cell group is provided with an inter-cell voltage balance correction circuit that performs voltage balance correction between adjacent cells in each cell group, and the series voltage of each cell group is formed using a transformer, coil, and switching circuit. A multi-series storage cell comprising a group voltage balance correction circuit for correcting the balance by alternating current coupling.

  (2) In the means (1), the inter-cell voltage balance correction circuit corrects the voltage balance between the two cells by charging and discharging the inductor current between the adjacent first cell and the second cell. A multi-series storage cell, characterized in that

  (3) In the above means (2), the inter-cell voltage balance correction circuit is configured using an inductor that is alternately connected to the first cell and the second cell and charges and discharges the inductor current. A multi-series storage cell characterized by

  (4) In the above means (2), the inter-cell voltage balance correction circuit includes a first inductor that discharges the inductor current charged by the first cell through the charging path of the second cell, and the second cell. It is configured using a second inductor that discharges the charged inductor current through the charging path of the first cell, and a switching circuit that switches between charging and discharging of the first and second inductors. A feature of the multi-series storage cell.

  (5) In any one of the above means (2) to (4), a plurality of inductors constituting the inter-cell voltage balance correction circuit are installed in the cell group, and the inductors are magnetically coupled to each other. A feature of the multi-series storage cell.

  (6) In any one of the above means (1) to (5), the inter-group voltage balance correction circuit is configured using a plurality of transformer coils that are magnetically coupled to each other at a transformation ratio of 1: 1. A feature of the multi-series storage cell.

  (7) In any one of the above means (1) to (6), the inter-group voltage balance correction circuit includes a primary coil connected to a series end of all cell groups via a switching circuit, and a series end of each cell group. A multi-series storage cell, characterized by being configured using a transformer having a secondary coil connected through a switching circuit.

  To provide a multi-series storage cell capable of performing voltage balance correction of all cells quickly and smoothly while improving workability such as assembly and replacement in a multi-series storage cell having a large number of series connections. it can.

  The operations / effects other than the above will be clarified from the description of the present specification and the accompanying drawings.

  FIG. 1 shows a first embodiment of a multi-series storage cell according to the present invention. The multi-series storage cell shown in the figure is a series connection of a large number (n) of storage cells 11 (B1 to Bn), and the series ends P1 and P2 of the power generation / load of an electric motor or the like that serves as power for the electric vehicle. It is connected to the apparatus 100 and used for charging and discharging.

  In the figure, n power storage cells B1 to Bn connected in series are cell groups (B1 and B2, B3 and B4,..., Bn-1 and Bn) that are continuous in the connection order. G1, G2, G3,..., Gm), and each cell group (G1, G2, G3,..., Gm) has an intercell voltage for correcting the voltage balance between adjacent cells. A balance correction circuit 31 is provided.

  The inter-cell voltage balance correction circuit 31 is an inductor-coupled voltage balance correction circuit configured using the inductor Lc and the switching circuits Sa and Sb, and includes adjacent first cells (B1, B3,... By charging and discharging the inductor current between Bn-1) and the second cells (B2, B4,..., Bn), voltage balance correction is performed between the two cells.

  The switching circuits Sa and Sb are configured using MOS-FETs and are alternately turned on and off by a two-phase pulse signal supplied from a control circuit (not shown). When one switching circuit Sa is on, the inductor current is charged from the first cell (B1, B3,..., Bn−1) to the inductor Lc. At this time, the other switching circuit Sb is turned off.

  When one switching circuit Sa is switched from on to off, the inductor current charged to Lc is discharged through the other switching circuit Sb while charging the second cells (B2, B4,..., Bn). Become so.

  Here, paying attention to the cells B1 and B2, when the voltage of B1 is higher than B2, the inductor current charged to the inductor Lc by B1 is discharged through the charging path of B2, and thus between the cells B1 and B2. Are equalized. On the other hand, when the voltage of B1 is lower than B2, the inductor current charged in the inductor Lc by B2 is discharged through the charging path of B1, thereby equalizing the voltage between the cells B1 and B2.

  In other words, if there is a voltage difference between two adjacent cells B1 and B2, the electric energy is transferred from the cell having the higher voltage to the cell having the lower voltage via the inductance Lc. The voltages of B1 and B2 are equalized. This balance correction operation is performed independently in each cell group (G1, G2, G3,..., Gm).

  A diode is connected in parallel to each of the switching circuits Sa and Sb, and this diode is formed by a parasitic diode (body diode) formed equivalently between the source and drain of the MOS-FET. This diode is in the reverse direction with respect to the voltage of the cell 11, but is in the forward direction with respect to the inductor current, thereby bringing the following effects.

  That is, if the inductor current remains during the period when both the switching circuits Sa and Sb are turned off, the remaining inductor current can continue to flow through the diode. As a result, the inductor current once generated in the inductor Lc can be used without waste for the voltage balance correction operation, and the generation of the surge voltage generated when the inductor current is cut off can be reliably suppressed.

  In the multi-series storage cell shown in FIG. 1, in addition to the inter-cell voltage balance correction circuit 31, an inter-group voltage balance for correcting the balance of the series voltage of each cell group (G1, G2, G3,..., Gm). A correction circuit 32 is provided.

  This inter-group voltage balance correction circuit 32 is a transformer-coupled voltage balance correction circuit using a transformer T1, and is wound around the same magnetic core 21 with the same number of turns and has a one-to-one transformation ratio. It is configured using a transformer coil (L1 to Lm) and a switching circuit Sc that is turned on and off in phase with each other.

  Each transformer coil (L1 to Lm) is connected to a series end of each cell group (G1, G2, G3,..., Gm). The switching circuit Sc is configured by using a MOS-FET, and is turned on / off in phase with each other in response to a pulse signal (clock signal) having a fixed period supplied from a control circuit (not shown).

  By this switching circuit Sc, the cell groups (G1, G2, G3,..., Gm) are AC-coupled with each other at a transformation ratio of 1: 1. Thereby, balance correction is performed such that the series voltage of each cell group (G1, G2, G3,..., Gm) becomes the same voltage.

  In the multi-series storage cell described above, the cells (B1 and B2, B3 and B4,..., Bn-1 and Bn) are grouped, and within the group (G1, G2, G3,..., Gm). By causing each cell to perform voltage correction of adjacent cells by an inductor coupling method, voltage balance correction within each cell group can be performed quickly and smoothly. At the same time, the series voltage of each cell group (G1, G2, G3,..., Gm) is balance-corrected by the transformer coupling method, so that voltage balance correction for all cells (B1 to Bn) can be performed quickly and smoothly. In addition, it can be made to be performed accurately.

  Further, in the embodiment shown in FIG. 1, only one set of the inductor Lc and the switching circuits Sa and Sb for performing the balance correction by the inductor coupling method is required for the two cells 11. As a result, the number of components of the inductor Lc and the switching circuits Sa and Sb can be significantly reduced as compared with the conventional method in which the voltage balance correction by the inductor coupling method is performed on all cells (B1 to Bn). This reduction in the number of components brings about an effect of reducing the heat generation amount and increasing the mounting density (collection density) of the cells (B1 to Bn).

  In addition, the transformer-coupled voltage balance correction circuit 32 requires wiring for connecting the transformer coils (L1 to Ln) and the cell groups (G1, G2, G3,..., Gm). Is only (m + 1) by adding one to the number of cell groups (G1, G2, G3,..., Gm), and voltage balance correction by the transformer coupling method is applied to all cells (B1 to Bn). Compared to the conventional method to be performed, the number of wirings is greatly reduced.

  As described above, in a multi-series storage cell having a large number of series connections, it is possible to quickly and smoothly perform voltage balance correction for all the cells while improving workability such as assembly and replacement.

  FIG. 2 is a circuit diagram showing the wiring state of the cell groups (G1, G2, G3,..., Gm) close to the actual state. As shown in FIG. In G2, G3,..., Gm), two cells are modularized. Operations such as assembly of multi-series storage cells and cell replacement can be efficiently performed by using the module as a unit.

  FIG. 3 shows an embodiment of a voltage balance correction circuit 31 using an inductor coupling method. The voltage balance correction circuit 31 of this system can be configured, for example, as shown in FIGS.

  The voltage balance correction circuit 31 shown in FIG. 6A is similar in principle to the inter-cell voltage balance correction circuit 31 shown in FIG. 1 or FIG. By charging and discharging the inductor current to and from the cell L2 between the cells B2, voltage balance correction is performed between the cells B1 and B2.

  The voltage balance correction circuit 31 shown in FIG. 5B includes a first inductor Lc1 that discharges the inductor current charged by the first cell B1 through the charging path of the second cell B2, and a second cell B2. The second inductor Lc2 that discharges the charged inductor current through the charging path of the first cell B1, and the switching circuits Sa and Sb that switch the charging and discharging of the first and second inductors Lc1 and Lc2 and the diode D1 and D2 are used.

  In the circuit 31, when the first switching circuit Sa is on, the inductor current is charged from the first cell B1 to the first inductor Lc1. This inductor current is discharged through the charging path of the second cell B2 via the diode D1 when the first switching circuit Sa is turned off.

  When the first switching circuit Sa is off, the second switching circuit Sb is turned on, and the inductor current is charged from the second cell B2 to the second inductor Lc2. This inductor current is discharged through the charging path of the first cell B1 via the diode D2 when the second switching circuit Sb is turned off.

  As described above, in the voltage balance correction circuit 31 in FIG. 5B, the balance correction operation by charging and discharging the inductor current is performed simultaneously in both the first and second cells B1 and B2. Thereby, the voltage balance correction between both cells B1 and B2 can be further accelerated.

  FIG. 4 shows an embodiment of a voltage balance correction circuit 32 using a transformer coupling method. This voltage balance correction circuit can be configured as shown in (a) and (b) of FIG.

  The voltage balance correction circuit 32 shown in FIG. 6A has the same principle as the inter-group voltage balance correction circuit 32 shown in FIG. 1 or FIG. 2, and each of the two cell groups G1 and G2 is switched to a switching circuit. By connecting to the coils L1 and L2 of the transformer T1 via Sc, the two cell groups G1 and G2 are AC-coupled at a transformation ratio of 1: 1 to perform voltage balance correction.

  Each of the cell groups G1 and G2 is configured by a module in which k power storage cells (B1 to Bk) are connected in series. In each cell group G1, G2, although not shown, an inter-cell voltage balance correction circuit using an inductor coupling method is provided.

  The voltage balance correction circuit 32 shown in FIG. 5B uses a transformer T1 having a primary coil Lo and secondary coils L1 and L2. Series terminals (P1, P2) of all cell groups (G1, G2) are connected to the primary coil Lo via a switching circuit Sc. Secondary coils L1, L2 are connected to each cell group (G1, G2) via diodes D1, D2 for rectification and backflow prevention.

  The secondary coils L1 and L2 are wound around the same magnetic core 21 with the same number of turns. The primary coil Lo is a wound pole in a direction in which D1 and D2 are turned off when Sc is turned on so that the core 21 can be excited by the series voltage of all cells. When Sc is turned on, the series voltage of all the cells is applied to Lo, and the core 21 is excited. Next, when Sc is turned off, the secondary windings L1 and L2 pass a current through D1 and D2 so as to maintain this exciting current. At this time, since the current flows in a concentrated manner in the lower voltage per turn, voltage balance correction is performed between the cell groups (G1, G2).

  A series voltage of all the cells is applied to the primary coil Lo while being turned on / off by the switching circuit Sc. This applied voltage is transformed at a predetermined voltage division ratio and appears in the secondary coils L1 and L2. The divided voltage appearing in the secondary coils L1, L2 is applied to the cell group (G1, G2) via the diodes D1, D2. Thereby, voltage balance correction between the cell groups (G1, G2) is performed.

  The inter-group voltage balance correction circuit 32 performs voltage balance correction by simultaneously redistributing the series voltage of all the cells to each cell group (G1, G2), thereby speeding up the balance correction operation. be able to.

  FIG. 5 shows a second embodiment of a multi-series storage cell according to the present invention. In the multi-series storage cell shown in the figure, four storage cells 11 (B1 to B4, B5 to B8,...) Are connected in series in each cell group (G1, G2,...). That is, four series cells (B1 to B4, B5 to B8,...) Constitute a cell group (G1, G2,...) Module.

  In each cell group (G1, G2,...), An inter-cell voltage balance correction circuit 31 using an inductor coupling method is installed. The inter-cell voltage balance correction circuit 31 uses two inductors Lc1 and Lc2. Both inductors Lc1 and Lc2 are wound around the same magnetic core 22 and are magnetically coupled to each other. That is, as shown in FIG. 6, the inductors Lc1 and Lc2 form a one-to-one transformer. Thereby, the inter-cell voltage balance correction circuit 31 can perform the balance correction of the voltages of the four cells (B1 to B4,...) With the two inductors Lc1 and Lc2.

  According to the above configuration, the number of wirings and parts in the cell group (G1, G2,...) Can be further reduced. Moreover, the number of series cells in each cell group (G1, G2,...) Has increased to four, so that the number of cell groups is greatly reduced. As a result, the number of transformers and coils of the inter-group voltage balance correction circuit 32 and the number of wires between the inter-group voltage balance correction circuit 32 and the storage cell column can be further greatly reduced.

  As described above, the present invention has been described based on the representative embodiments, but the present invention can have various modes other than those described above. For example, the number of cells in the cell group (G1, G2,...) Can be 3 or an arbitrary number of 5 or more.

  To provide a multi-series storage cell capable of performing voltage balance correction of all cells quickly and smoothly while improving workability such as assembly and replacement in a multi-series storage cell having a large number of series connections. it can.

1 is a circuit diagram showing a first embodiment of a multi-series storage cell according to the present invention. FIG. 2 is a circuit diagram in which a part of the circuit shown in FIG. 1 is further embodied. It is a circuit diagram which shows embodiment of the voltage balance correction | amendment circuit between cells used by this invention. It is a circuit diagram which shows 1st Embodiment of the voltage balance correction circuit between groups used by this invention. 1 is a circuit diagram showing a first embodiment of a multi-series storage cell according to the present invention. FIG. 6 is a circuit diagram in which a part of the circuit shown in FIG. 5 is further embodied. It is a circuit diagram which shows the 1st structural example of the conventional multi-series electrical storage cell. It is a circuit diagram which shows the 2nd structural example of the conventional multi-series electrical storage cell.

Explanation of symbols

100 Power generation / load device 11 Storage cell 11 (B1 to Bn)
21, 22 Magnetic core 31 Inter-cell voltage balance correction circuit 32 Inter-group voltage balance correction circuit G1-Gm Cell group Lc, Lc1, Lc2 Inductor L1-Lm Transformer coils P1, P2 Series terminals Sa, Sb, Sc switching circuit T1 transformer

Claims (7)

  A multi-series storage cell including a plurality of storage cells connected in series and having a voltage balance correction circuit that equalizes the voltage of each cell, wherein the multi-series storage cells are connected to a plurality of series cell groups that are continuous in the connection order. In each cell group, an inter-cell voltage balance correction circuit for correcting voltage balance between adjacent cells is provided, and the series voltage of each cell group is formed using a transformer, a coil and a switching circuit. A multi-series storage cell, characterized in that an inter-group voltage balance correction circuit for correcting the balance is provided.   The inter-cell voltage balance correction circuit according to claim 1, wherein the voltage balance correction is performed between both cells by charging and discharging the inductor current between the adjacent first cell and second cell. A multi-series storage cell.   3. The multi-cell voltage balance correction circuit according to claim 2, wherein the inter-cell voltage balance correction circuit is configured using an inductor that is alternately connected to the first cell and the second cell and charges and discharges the inductor current. Series storage cell.   The inter-cell voltage balance correction circuit according to claim 2, wherein the inter-cell voltage balance correction circuit includes a first inductor that discharges the inductor current charged by the first cell through a charging path of the second cell, and an inductor current that is charged by the second cell. A multi-series circuit comprising: a second inductor that discharges the first and second inductors through a charging path of the first cell; and a switching circuit that switches between charging and discharging of the first and second inductors. Power storage cell.   5. The multi-series storage cell according to claim 2, wherein a plurality of inductors constituting the inter-cell voltage balance correction circuit are provided in the cell group, and the inductors are magnetically coupled to each other. .   6. The multi-series storage cell according to claim 1, wherein the inter-group voltage balance correction circuit includes a plurality of transformer coils that are magnetically coupled to each other at a one-to-one transformation ratio. . 7. The inter-group voltage balance correction circuit according to claim 1, wherein the inter-group voltage balance correction circuit is connected to the serial ends of all cell groups via a switching circuit, and connected to the serial ends of each cell group via a switching circuit. A multi-series energy storage cell, characterized in that the multi-series energy storage cell is configured using a transformer including a secondary coil.

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