JP2011065794A - Secondary battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery module having a small loss, good efficiency, and high reliability, by equalizing currents flowing between serially-connected battery cells. <P>SOLUTION: The secondary battery module, formed by serially-connecting a plurality of parallel-connected battery groups obtained by parallel-connecting a plurality of battery cells, includes: a first connecting conductor between cell terminals to electrically connect between positive electrode terminals of the battery cells of the parallel connected battery groups; a second connecting conductor between cell terminals to electrically connect between negative electrode terminals of the parallel-connected battery groups; and a third connecting conductor between cell terminals to electrically connect the connecting conductors between the cell terminals of the parallel-connected battery groups each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a secondary battery module formed by connecting a plurality of parallel connection battery groups formed by connecting a plurality of battery cells in parallel.

  A battery device used in a vehicle such as a hybrid electric vehicle or an electric vehicle needs to have high output and cope with frequent output changes. Such a battery device is generally configured by incorporating a battery module in which a plurality of battery cells are electrically connected in series and in parallel and mechanically integrated according to a required output and capacity. Many.

When the battery module is configured by connecting a plurality of battery cells in series and parallel, the battery module is configured to monitor the voltage of each parallel cell group that the current is equally distributed to the battery cells connected in parallel and there is no imbalance. It is required that the value has no imbalance between the parallel cell groups and that the loss generated by the wiring member that connects the cell terminals in series and parallel is small.

  The configuration of a conventional battery module is shown in FIGS. 9, 10, 11, and 12. 9 and 10 are three-dimensional views showing the mechanical configuration of the battery module, and FIG. 11 is a circuit diagram showing an electrical connection state in the battery module.

  As shown in FIG. 9, the battery module includes battery cells C1, C2, and C3 connected in parallel, battery cells C4, C5, and C6 connected in parallel, and battery cells C7, C8, and C9 connected in parallel. Are connected in series.

Each of the battery cells (C1 to C9) has a box-shaped outer shape, and cell terminals T1 to T18 are provided on the upper part.

The terminals of adjacent battery cells are connected in parallel or in series by inter-cell terminal parallel connection conductors L1 and L2 or inter-cell terminal serial / parallel connection conductors L3 and L4 as shown in FIG. The inter-cell terminal parallel connection conductors L1 and L2 and the inter-cell terminal serial / parallel connection conductors L3 and L4 are made of, for example, a good electrical conductor material such as aluminum, and are connected to the cell terminals T1 to T18 made of the same kind of material. Joined by welding method.

Furthermore, module terminal portions TP and TN for connecting the battery module to the outside are provided at the ends of the inter-cell terminal parallel connection conductors L1 and L2, respectively.

  The cell terminal parallel connection conductors L1 and L2 and the cell terminal serial / parallel connection conductors L3 and L4 are provided with voltage detection terminals D1, D2, D3, and D4 for voltage detection. As shown in FIG. 12, a voltage monitoring board DB is provided on the upper part of the battery module so as to cover the inter-cell terminal parallel connection conductors L1 and L2 and the inter-cell terminal serial / parallel connection conductors L3 and L4. Terminals D1, D2, D3, and D4 are connected to an electric circuit on the voltage monitoring board DB.

The battery module configured as described above has the following problems.

The current sharing between the battery cells connected in parallel is likely to be uneven.

FIG. 11 is also a diagram showing an equivalent circuit of the battery module shown in FIG. In FIG. 11, considering the case where the charging current flows through the battery module, the charging current is supplied to each battery cell from the module terminal portion TP via the inter-cell terminal parallel connection conductor L1 and the inter-cell terminal serial / parallel connection conductors L4 and L3. Flows to another module terminal TN.

  In the inter-cell terminal parallel connection conductor L1, an equivalent resistance r1 is provided between the module terminal portion TP and the cell terminal T1, an equivalent resistance r2 is provided between the cell terminal T1 and the cell terminal T2, and the cell terminal T2 and the cell terminal T3. An equivalent resistance r3 exists between them. Similarly, in the inter-cell terminal parallel connection conductor L2, an equivalent resistance r4 is provided between the module terminal portion TN and the cell terminal T18, an equivalent resistance r5 is provided between the cell terminal T18 and the cell terminal T17, and the cell terminal T17 and the cell terminal. An equivalent resistance r6 exists between T16.

In the serial-parallel connection conductor L4 between the cell terminals, an equivalent resistance r11 is provided between the cell terminal T4 and the cell terminal T7, an equivalent resistance r12 is provided between the cell terminal T4 and the cell terminal T8, and the cell terminal T4 and the cell terminal T9. An equivalent resistance r13, an equivalent resistance r14 between the cell terminal T5 and the cell terminal T7, an equivalent resistance r15 between the cell terminal T5 and the cell terminal T8, and an equivalent resistance r16 between the cell terminal T5 and the cell terminal T9. An equivalent resistance r17 exists between the cell terminal T6 and the cell terminal T7, an equivalent resistance r18 exists between the cell terminal T6 and the cell terminal T8, and an equivalent resistance r19 exists between the cell terminal T6 and the cell terminal T9.

Similarly, in the serial-parallel connection conductor L3 between the cell terminals, an equivalent resistance r21 is provided between the cell terminal T10 and the cell terminal T13, an equivalent resistance r22 is provided between the cell terminal T10 and the cell terminal T14, and the cell terminal T10 and the cell terminal. An equivalent resistance r23 between the cell terminal T11 and the cell terminal T13, an equivalent resistance r24 between the cell terminal T11 and the cell terminal T13, an equivalent resistance r25 between the cell terminal T11 and the cell terminal T14, and between the cell terminal T11 and the cell terminal T15. An equivalent resistance r26, an equivalent resistance r27 between the cell terminal T12 and the cell terminal T13, an equivalent resistance r28 between the cell terminal T12 and the cell terminal T14, and an equivalent resistance r29 between the cell terminal T12 and the cell terminal T15 exist. To do.

It should be noted here that the equivalent resistances of the inter-cell terminal series / parallel connection conductors L3 and L4 are smaller than the equivalent resistances of the inter-cell terminal parallel connection conductors L1 and L2. For example, the resistance values of r11 to r13 are relatively smaller than the equivalent resistances r2 and r3.

When the current sharing of the battery cells C1, C2, and C3 is compared in the above-described charging current path (flow path from the module terminal part TP to the module terminal part TN) due to the difference in equivalent resistance value, the current of the battery cell C1 is compared. Is the largest, and the battery cell C3 is the smallest.

  Similarly, when the current sharing of the battery cells C7, C8, and C9 is compared, the current of the battery cell C9 is the largest and the battery cell C7 is the smallest.

As described above, since there is an equivalent resistance in the conductor connecting the terminals, current non-uniformity occurs between the parallel cells, thereby increasing the margin and reducing the life due to the non-uniform temperature rise value. Since it invites, it is not preferable.

  The second problem is that the voltage monitoring value of each parallel cell group is different between the parallel cell groups. Battery voltage is monitored for the purpose of protecting battery cells. The voltage is monitored by the voltage monitoring board DB via the voltage detection units D1, D2, D3, and D4 formed in the inter-cell terminal parallel connection conductors L1 and L2 or the inter-cell terminal serial / parallel connection conductors L3 and L4. That is, the voltage of the parallel cell group configured by the battery cells C1, C2, and C3 is detected by the voltage detection units D1 and D2. Similarly, the voltage of the parallel cell group constituted by the battery cells C4, C5, and C6 is detected by the voltage detection units D2 and D3. Furthermore, the voltage of the parallel cell group constituted by the battery cells C7, C8, and C9 is detected by the voltage detection units D3 and D4.

  It should be noted here that the value of the detection voltage varies depending on the difference in the position where the voltage detection unit is formed on each connection conductor.

Since the voltage rise or voltage drop is determined by the product of the equivalent resistance inside the cell terminal parallel connection conductors L1 and L2 and the cell terminal serial / parallel connection conductors L3 and L4, and the energization current, the voltage fluctuation due to the equivalent resistance occurs in the cell voltage. Minutes are added.

  The voltage fluctuation due to the equivalent resistance varies depending on the position where the voltage detection unit is formed. As shown in FIG. 9, when the voltage detectors D1, D2, D3, D4 are provided at the illustrated positions of the inter-cell terminal parallel connection conductors L1, L2 and the inter-cell terminal serial / parallel connection conductors L3, L4, respectively. In FIG. 11, cell terminals T1, T6, T12, and T18 correspond to voltage detectors D1, D2, D3, and D4, respectively.

The voltage between the cell terminal T1 and the cell terminal T6 is smaller than the voltage between the cell terminal T6 and the cell terminal T12 or the voltage between the cell terminal T12 and the cell terminal T18. Between the cell terminals T1 and T6, there is a series circuit of equivalent resistances r3 and r2 in addition to the battery cell C3, while an equivalent resistance r19 is provided between the cell terminals T6 and T12 in addition to the battery cell C6. Exists. Since two equivalent resistances exist between the cell terminals T1 and T6, the voltage drop is larger than that between the cell terminals T6 and T12. Therefore, between the cell terminals T1 and T6. The voltage is smaller than the voltage between the cell terminal T6 and the cell terminal T12 or the voltage between the cell terminal T12 and the cell terminal T18.

  The third problem is a loss generated by the wiring member that connects the cell terminals in series and parallel. In the configuration of FIGS. 9 and 10, there is not a portion where the resistance is particularly large in the inter-cell terminal parallel connection conductor or the inter-cell terminal serial / parallel connection conductor. However, the resistance of the conductor increases the generation loss, increases the temperature rise of the battery cell, and further reduces the efficiency.

JP-A-9-219181

  The present invention has been made in view of the above circumstances, and provides a secondary battery module that equalizes the current flowing through battery cells connected in series and parallel, has low loss, is efficient, and has high reliability. With the goal.

  The secondary battery module according to the present invention is a secondary battery module in which a plurality of parallel-connected battery groups in which a plurality of battery cells are connected in parallel is connected in series, and the positive terminals of the battery cells in the parallel-connected battery group are electrically connected. Between the first inter-cell terminal connection conductor connected to the second cell terminal, the second inter-cell terminal connection conductor electrically connecting the negative electrode terminals of the parallel connection battery group, and the inter-cell terminal connection conductor of the parallel connection battery group. A secondary battery module comprising a third inter-terminal connecting conductor connected electrically.

  ADVANTAGE OF THE INVENTION According to this invention, the electric current which flows into the battery cell connected in series and parallel is equalized, and an efficient and reliable secondary battery module with few losses can be provided.

It is a figure for demonstrating the structure of the secondary battery module which concerns on 1st Embodiment of this invention. It is a figure for demonstrating the structure of the secondary battery module which concerns on 1st Embodiment of this invention. It is a figure for demonstrating the electrical connection state of the battery module which concerns on 1st Embodiment of FIG. It is a figure for demonstrating the structure of the secondary battery module which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating the structure of the secondary battery module which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating the electrical connection state of the battery module which concerns on 1st Embodiment of FIG. It is a figure for demonstrating a part of component of the secondary battery module which concerns on 3rd Embodiment of this invention. It is a figure for demonstrating a part of component of the secondary battery module which concerns on 4th Embodiment of this invention. It is a figure for demonstrating the structure of the conventional secondary battery module. It is a figure for demonstrating the structure of the conventional secondary battery module. It is a figure for demonstrating the electrical connection state of the battery module of FIG. It is a figure for demonstrating the structure of the conventional secondary battery module.

  Hereinafter, the secondary battery module according to the first embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the secondary battery module includes battery cells C1, C2, and C3 connected in parallel, battery cells C4, C5, and C6 connected in parallel, and battery cells C7, C8, and C9. Are connected in parallel and connected in series.

Each of the battery cells (C1 to C9) has a box-shaped outer shape, and cell terminals T1 to T18 are provided on the upper part.

As shown in FIGS. 1 and 2, terminals of adjacent battery cells are connected in parallel or in series by cell terminal parallel connection conductors L11 and L12 or cell terminal serial / parallel connection conductors L13 and L14. The inter-cell terminal parallel connection conductors L11 and L12 and the inter-cell terminal serial / parallel connection conductors L13 and L14 are made of, for example, a good electrical conductor material such as aluminum, and are connected to the cell terminals T1 to T18 made of the same kind of material. Joined by welding method.

Furthermore, module terminal portions TP and TN for connecting the battery module to the outside are provided at the ends of the inter-cell terminal parallel connection conductors L11 and L12, respectively. Here, the series-parallel connection conductors L13 and L14 between the cell terminals have a U-shape, as shown in the figure, instead of the conventional square shape. The cell terminal series-parallel connection conductor L13 connects the cell terminals T4, T5, T6 of the battery cells C1, C2, C3, and further connects the cell terminals T7, T8, T9 of the battery cells C4, C5, C6, The cell terminal T6 and the cell terminal T9 are connected.

  In addition, voltage detection terminals D11, D12, D13, and D14 for voltage detection are provided on the inter-cell terminal parallel connection conductors L1 and L2 and the inter-cell terminal serial / parallel connection conductors L3 and L4. On the upper part of the battery module, a voltage monitoring board (not shown) is provided so as to cover the inter-cell terminal parallel connection conductors L11, L12 and the inter-cell terminal serial / parallel connection conductors L13, L14, and the voltage detection terminals D11, D12, D13, D14 is connected to an electric circuit on the voltage monitoring board.

FIG. 3 is a circuit diagram showing an electrical connection state in the secondary battery module in the present embodiment. In FIG. 3, focusing on the battery cells C1, C2, and C3, in the current path from the cell terminals T1 to T6, the inter-cell terminal parallel connection conductor or the inter-cell terminal serial / parallel connection conductor is used for the current path for any battery cell. Of the four equivalent resistances r2, r3, r101, r102 existing through the two equivalent resistances.

Similarly, when attention is paid to the battery cells C4, C5, and C6, in the current path from the cell terminals T9 to T10, the current path for any of the battery cells is either the parallel connection conductor between cell terminals or the series-parallel connection conductor between cell terminals. Of the existing four equivalent resistances r104, r105, r111, r112, two equivalent resistances are routed.

Similarly, when attention is paid to the battery cells C7, C8, C9, in the current path from the cell terminals T13 to T18, the current path for any battery cell is either the parallel connection conductor between cell terminals or the series-parallel connection conductor between cell terminals. Of the existing four equivalent resistances r4, r5, r114, r115, two equivalent resistances are routed.

As described above, the equivalent resistances of the current paths passing through any of the battery cells can be made equal. Thereby, the electric current which flows into each battery cell can be equalized.

As a result, it is possible to avoid a reduction in the life due to a reduction in energization margin to the cell and equalization of the generated temperature rise value.

On the other hand, the battery voltage is monitored for the purpose of protecting the secondary battery cell. The voltage is monitored by a voltage monitoring board (not shown) via the voltage detectors D11, D12, D13, D14 formed in the inter-cell terminal parallel connection conductors L11, L12 or the inter-cell terminal serial / parallel connection conductors L13, L14. .

That is, the voltage of the parallel cell group constituted by the secondary battery cells C1, C2, and C3 is detected by the voltage detection units D11 and D12. Similarly, the voltage of the parallel cell group comprised by the secondary battery cells C4, C5, C6 is detected by the voltage detection units D12, D13. Furthermore, the voltage of the parallel cell group comprised by battery cell C7, C8, C9 is detected by the voltage detection parts D13 and D14.

Next, a secondary battery module according to the second embodiment of the present invention will be described below with reference to the drawings.

  4 and 5, the secondary battery module includes battery cells C1, C2, and C3 connected in parallel, battery cells C4, C5, and C6 connected in parallel, and battery cells C7, C8, and C9. Are connected in parallel and connected in series.

Each of the battery cells (C1 to C9) has a box-shaped outer shape, and cell terminals T1 to T18 are provided on the upper part.

The terminals of adjacent battery cells are connected in parallel or in series by cell terminal parallel connection conductors L21 and L22 or cell terminal serial / parallel connection conductors L23 and L24 as shown in FIGS. The inter-cell terminal parallel connection conductors L21 and L22 and the inter-cell terminal serial / parallel connection conductors L23 and L24 are made of, for example, a good electrical conductor material such as aluminum, and the cell terminals T1 to T18 made of the same kind of material are used. Joined by welding method.

Further, module terminal portions TP and TN for connecting the battery module to the outside are provided at the ends of the inter-cell terminal parallel connection conductors L21 and L22, respectively. Here, the series-parallel connection conductors L23 and L24 between the cell terminals have a U-shape, as shown in the figure, instead of the conventional square shape. This series-parallel connection conductor L23 between the cell terminals connects the cell terminals T4, T5, T6 of the battery cells C1, C2, C3, and further connects the cell terminals T7, T8, T9 of the battery cells C4, C5, C6, The cell terminal T6 and the cell terminal T9 are connected.

FIG. 6 is a circuit diagram showing an electrical connection state in the secondary battery module in the present embodiment. In FIG. 6, focusing on the battery cells C1, C2, and C3, in the current path from the cell terminals T1 to T6, the inter-cell terminal parallel connection conductor or the inter-cell terminal serial / parallel connection conductor is used for the current path for any battery cell. Of the four equivalent resistances r2, r3, r101, r102 existing through the two equivalent resistances.

Similarly, when attention is paid to the battery cells C4, C5, and C6, in the current path from the cell terminals T9 to T10, the current path for any of the battery cells is either the parallel connection conductor between cell terminals or the series-parallel connection conductor between cell terminals. Of the existing four equivalent resistances r104, r105, r111, r112, two equivalent resistances are routed.

Similarly, when attention is paid to the battery cells C7, C8, C9, in the current path from the cell terminals T13 to T18, the current path for any battery cell is either the parallel connection conductor between cell terminals or the series-parallel connection conductor between cell terminals. Of the existing four equivalent resistances r4, r5, r114, r115, two equivalent resistances are routed.

As described above, the equivalent resistances of the current paths passing through any of the battery cells can be made equal. Thereby, the electric current which flows into each battery cell can be equalized.

As a result, it is possible to avoid a reduction in the life due to a reduction in energization margin to the cell and equalization of the generated temperature rise value.

Furthermore, as shown in FIG. 4 and FIG. 5, the voltage detection terminals D21, D22, D23, and D24 for voltage detection are included in the inter-cell terminal parallel connection conductors L21 and L22 and the inter-cell terminal serial / parallel connection conductors L23 and L24. Is provided. In addition, the voltage detection terminal D21 is provided in the intermediate part of the width direction of the parallel connection conductor L21 between plate-shaped cell terminals, as the figure shows. There is a difference in that the conventional voltage detection terminal D1 is provided at the end of the inter-cell terminal parallel connection conductor L1. Similarly, as shown in the drawing, the voltage detection terminal D24 is provided in the intermediate portion in the width direction of the plate-shaped inter-cell terminal parallel connection conductor L22.

Furthermore, as shown in the drawing, the voltage detection terminal D22 is provided at an intermediate position between the cell terminals T6 and T9 of the plate-like inter-cell terminal series-parallel connection conductor L23. There is a difference in that a conventional voltage detection terminal is provided at an end of a parallel connection conductor between cell terminals. Similarly, as shown in the drawing, the voltage detection terminal D23 is provided at an intermediate position between the cell terminals T10 and T13 of the plate-like inter-cell terminal series-parallel connection conductor L24.

FIG. 6 is a circuit diagram showing an electrical connection state in the secondary battery module in the present embodiment.

6, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, since the voltage detection terminal D21 is provided between the cell terminal T1 and the module terminal portion TP, an equivalent circuit r1b between the cell terminal T1 and the voltage detection terminal D21, and the voltage detection terminal D21. And the equivalent circuit r1a between the module terminal portion TP have substantially the same resistance value.

Similarly, since the voltage detection terminal D24 is provided between the cell terminal T18 and the module terminal portion TN, the equivalent circuit r6a between the cell terminal T18 and the voltage detection terminal D24, the voltage detection terminal D24, and the module The equivalent circuit r1b between the terminal portion TN has almost the same resistance value.

On the other hand, since the voltage detection terminal D22 is provided between the cell terminal T6 and the cell terminal T9, the equivalent circuit r103a between the cell terminal T6 and the voltage detection terminal D22, the voltage detection terminal D22, and the cell terminal T9. The equivalent circuit r103b between the two has almost the same resistance value.

Similarly, since the voltage detection terminal D23 is provided between the cell terminal T10 and the cell terminal T13, an equivalent circuit r113a between the cell terminal T10 and the voltage detection terminal D23, the voltage detection terminal D23, and the cell terminal The equivalent circuit r113b between T13 has almost the same resistance value.

With this configuration, when considering three voltages between the voltage detection terminals D21 to D22, between the voltage detection terminals D22 to D23, and between the voltage detection terminals D23 to D24, the voltage difference between the parallel cell groups themselves is Due to the difference in the position of the detection unit, the phenomenon that the resistance value of the parallel connection conductor or the series-parallel connection conductor is different is eliminated. Therefore, it is possible to eliminate the occurrence of a voltage difference due to it.

  By adopting such a configuration, the detection voltages can be made uniform. Since there is no unbalance between the parallel cell groups of the voltage monitoring value, an unnecessary margin can be removed.

A third embodiment of the present invention will be described with reference to the drawings. 7 and 8 show the present embodiment.

In the configuration described above, when the cells are connected by wiring, the conduction current for three cells passes through the series connection part of the plate-like series-parallel connection conductors L23 and L24 between the cell terminals. As a result, the amount of current is large, and the amount of heat generated is proportionally increased. An increase in the amount of heat generation is not preferable because it causes a decrease in efficiency and a decrease in reliability due to an increase in temperature of the battery cell.

FIG. 7 shows a structure in which a conductive member L233 is formed in a series connection portion of series-parallel connection conductors. The conductive member L233 is assumed to be a good conductor metal such as aluminum, and is formed integrally with the series-parallel connection conductor or another part is joined.

Further, in FIG. 8, the conductive member L233 shown in FIG. 7 is replaced with a fin-shaped member L234.

By configuring the series-parallel connection conductor in this way, first, the resistance value of the series connection portion can be reduced. This is a resistance reduction effect due to an increase in conductor cross-sectional area. Moreover, the fin shape described in FIG. 7 can remarkably increase the heat radiation area. As a result, it is possible to suppress an increase in the temperature of the series connection part due to a synergistic effect of suppressing the heat generation amount by reducing the resistance value and improving the cooling efficiency by increasing the heat radiation area. Accordingly, it is possible to avoid a decrease in efficiency and a decrease in reliability.

C1 to C9: Battery cells, L11: Parallel connection conductor between cell terminals, L12 ... Parallel connection conductor between cell terminals, L13 ... Series / parallel connection conductor between cell terminals, L14 ... Series / parallel connection conductor between cell terminals, D11 to D14 ... Voltage Detection terminal

Claims (4)

In a secondary battery module formed by connecting a plurality of parallel connection battery groups formed by connecting a plurality of battery cells in parallel,
A first inter-terminal connecting conductor for electrically connecting the positive terminals of the battery cells of the parallel-connected battery group;
A second inter-terminal connecting conductor for electrically connecting the negative terminals of the battery cells of the parallel-connected battery group;
A secondary battery module, comprising: a third inter-cell terminal connection conductor that electrically connects inter-cell terminal connection conductors of the parallel connection battery group. A positive-side module terminal that supplies electric power from the secondary battery module to one end of the first inter-cell terminal connection conductor, and an external end from the secondary battery module to one end of the second inter-cell terminal connection conductor The secondary battery module according to claim 1, further comprising a negative station side module terminal for supplying electric power. The inter-cell terminal connecting conductor is configured in a plate shape, and the end of the first inter-cell terminal connecting conductor and the end of the second inter-cell terminal connecting conductor are connected by the third inter-cell terminal connecting conductor. The secondary battery module according to claim 2, wherein   The secondary battery module according to claim 3, wherein a voltage detection unit that detects a voltage of the cell battery is provided in a central portion of the plate-shaped inter-cell terminal connection conductor.

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