Power storage module

Abstract

This power storage module comprises a plurality of power storage devices (10) and a current collector plate (30). The power storage module has a first row including a plurality of power storage devices and a second row including a plurality of power storage devices. The current collector plate connects first electrodes of the plurality of power storage devices in the first row in parallel, and also connects the first electrodes of the plurality of power storage devices in the first row in series with second electrodes of the plurality of power storage devices in the second row. The current collector plate includes: a base part; first leads (36) extending from the base part and connected to the first electrodes of the power storage devices in the first row; second leads (38) extending from the base part and connected to the second electrodes of the power storage devices in the second row; a plurality of first connection parts where the plurality of first leads and the base part are connected; and a plurality of second connection parts where the plurality of second leads and the base part are connected. A pair of first connection parts are disposed between a pair of second connection parts adjacent to each other in a first direction among the plurality of second connection parts, and the pair of first connection parts are arranged in the first direction.

Description

Energy storage module

[0001] The present disclosure relates to an energy storage module that houses a plurality of energy storage devices.

[0002] Conventionally, a power storage module accommodates multiple power storage devices, which are connected in parallel and in series to obtain a predetermined capacity and voltage. Power storage devices include secondary batteries such as lithium-ion batteries and capacitors.

[0003] In this power storage module, a predetermined number of power storage devices are connected in parallel, and a predetermined number of groups of parallel-connected power storage devices are connected in series to obtain a desired output.

[0004] Patent Document 1 discloses an example of such an electricity storage module.

[0005] International Publication No. WO2014-050678

[0006] In a power storage module that accommodates a large number of power storage devices, further improvement in reliability is required.

[0007] An energy storage module according to one aspect of the present disclosure is an energy storage module including a plurality of energy storage devices each having a first pole and a second pole, and a current collector plate that electrically connects the plurality of energy storage devices to one another, wherein the plurality of energy storage devices include a first energy storage device group aligned in a first direction and a second energy storage device group aligned in the first direction, the first energy storage device group and the second energy storage device group aligned in a second direction perpendicular to the first direction, and the current collector plate connects each of the plurality of first poles of the first energy storage device group in parallel and connects each of the plurality of first poles of the first energy storage device group in series to a corresponding one of the plurality of second poles of the second energy storage device group. The current collecting plate has a base, a plurality of first leads extending from the base and connecting to the plurality of first poles of the first storage device group, a plurality of second leads extending from the base and connecting to the plurality of second poles of the second storage device group, a plurality of first connection portions connecting the plurality of first leads to the base, and a plurality of second connection portions connecting the plurality of second leads to the base, and a pair of first connection portions of the plurality of first connection portions are arranged between a pair of second connection portions of the plurality of second connection portions that are adjacent to each other in the first direction, and the pair of first connection portions are arranged side by side in the first direction.

[0008] Another aspect of the energy storage module according to the present disclosure is an energy storage module including a plurality of energy storage devices each having a first pole and a second pole, and a current collector plate electrically connecting the plurality of energy storage devices to one another, wherein the plurality of energy storage devices include a first energy storage device group aligned in a first direction and a second energy storage device group aligned in the first direction, the first energy storage device group and the second energy storage device group aligned in a second direction perpendicular to the first direction, and the current collector plate connects each of the plurality of first poles of the first energy storage device group in parallel and connects each of the plurality of first poles of the first energy storage device group in series to a corresponding one of the plurality of second poles of the second energy storage device group. The current collecting plate has a base, a plurality of first leads extending from the base and connecting to the plurality of first poles of the first storage device group, a plurality of second leads extending from the base and connecting to the plurality of second poles of the second storage device group, a plurality of first connection portions connecting the plurality of first leads to the base, and a plurality of second connection portions connecting the plurality of second leads to the base, and a pair of second connection portions of the plurality of second connection portions are arranged between a pair of first connection portions of the plurality of first connection portions that are adjacent to each other in the first direction, and the pair of second connection portions are arranged side by side in the first direction.

[0009] The energy storage module according to the present disclosure can improve reliability.

[0010] It is a circuit diagram showing the configuration of an electricity storage module.It is a diagram showing the appearance of an electricity storage device.It is a plan view showing the configuration of a current collector plate of an electricity storage module according to an embodiment.It is a plan view showing the configuration of a current collector plate of a comparative example.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiments do not limit the present disclosure, and configurations formed by selectively combining multiple examples are also included in the present disclosure.

[0012] Overall Configuration Fig. 1 is a circuit diagram showing the configuration of a power storage module 100. In this example, the power storage device 10 is a battery, but it may also be a capacitor or the like. Note that the battery may be a secondary battery that repeatedly charges and discharges, such as a lithium ion battery.

[0013] In the first row of the energy storage device group 101 (including the first energy storage device 10a and the second energy storage device 10b) aligned in the first direction in the figure, the positive electrodes are commonly connected to each other. Meanwhile, the negative electrodes of the energy storage device group 101 in the first row are commonly connected to each other and connected to a negative terminal 12, which is one output terminal of the energy storage module 100. Note that in the energy storage module of the present disclosure, the energy storage devices that are connected in parallel are not limited to only the first row of the energy storage device group 101. Energy storage devices in other rows may also be connected in parallel with the first row.

[0014] In the present disclosure, "arranged in the first direction" includes "energy storage devices 10 arranged in the first direction" even if they are arranged in a zigzag pattern, as long as they are arranged along the first direction overall.

[0015] The positive electrodes of the first power storage device group 101 are connected to a corresponding negative electrode of the second power storage device group 102 (including the third power storage device 10c and the fourth power storage device 10d) that are aligned in a first direction (along the first axis). The first power storage device group 101 and the second power storage device group 102 are aligned in a second direction (along the second axis) that is perpendicular to the first direction. Note that in the power storage module of the present disclosure, the second power storage device group 102 is not the only device that is connected in series to the first power storage device group 101. The first power storage device group 101 may be connected in series with the second power storage device group 102 and another power storage device group in another column.

[0016] Furthermore, the plurality of power storage devices 10 in each column do not necessarily have to be arranged on a single straight line, but may be arranged so as to be shifted from one another in the second direction.

[0017] In this way, the positive electrodes of the storage devices 10 of the first storage device group 101 are sequentially connected to the negative electrodes of the storage devices 10 of the second storage device group 102, which is the next column, so that the storage device groups of each column are connected in parallel and then connected in series as many times as the number of columns.

[0018] The positive electrodes of the power storage device group 10 x in the final column are connected in parallel and connected to the positive output terminal 14 of the power storage module 100 .

[0019] "Battery Appearance" FIG. 2 is a diagram showing the appearance of one energy storage device 10. The energy storage device 10 is, for example, a cylindrical battery. A positive electrode terminal 22 is disposed in the center of the upper end surface of the energy storage device 10. A negative electrode terminal 24 is disposed on the lower end surface. The negative electrode terminal may also be disposed in the peripheral portion of the upper end surface, which is indicated by the sandy area in FIG. 2. One example of the configuration of the energy storage device 10 may include an electrode assembly in which strip-shaped positive and negative electrode plates are wound with a separator interposed therebetween, a cylindrical outer can containing this electrode assembly together with an electrolyte, a conductive seal that closes the opening of the outer can, a gasket that provides electrical insulation between the seal and the outer can, an internal negative electrode lead that electrically connects the negative electrode plate to the bottom of the outer can within the outer can, and an internal positive electrode lead that electrically connects the positive electrode plate to the seal. The gasket may cover the top surface, bottom surface, and outer peripheral surface connecting the top and bottom surfaces of the sealing body, be provided on the outer peripheral surface of the outer can, and be sandwiched in the winding axis direction of the electrode body between a protruding groove portion on the inner peripheral surface of the outer can and a crimping portion that bends the opening of the outer can inward to seal the inside of the outer can. Here, the sandy area (negative electrode terminal 24) in Figure 2 may be the crimping portion of the outer can. The positive electrode terminal 22 in Figure 2 may be the top surface of the sealing body. The configuration of the energy storage device is not limited to the above configuration.

[0020] "Configuration of Current Collector Plate" Fig. 3 is a plan view showing the configuration of the current collector plate 30. This current collector plate 30 connects in parallel the positive electrodes of the power storage devices 10 in the first column (first power storage device, second power storage device, fifth power storage device, etc.) and connects in parallel the negative electrodes of the power storage devices 10 in the second column (third power storage device, fourth power storage device, sixth power storage device, etc.). In other words, it is what is called an intermediate current collector plate located just before the second to final columns in Fig. 1. The current collector plate (positive electrode current collector plate) that connects in parallel the positive electrodes of the final column and the current collector plate (negative electrode current collector plate) that connects in parallel the negative electrodes of the final column only have a lead connected to one electrode of the power storage device, and are configured differently from the current collector plate 30 of the present disclosure.

[0021] In FIG. 3, the current collector 30 connects four power storage devices 10 in parallel, but the number of power storage devices 10 connected in parallel by the current collector 30 may be any number greater than or equal to two (plural).

[0022] The current collector plate 30 is a plate-like member with a horizontally elongated shape corresponding to the number of power storage devices 10 to be connected. The current collector plate has a plate-like base and a plurality of first leads and a plurality of second leads (described later) extending from the base. At the base, current flows from the first leads to the second leads, and the power storage devices 10 in each column are connected in parallel. The current collector plate 30 is preferably made of a conductive material such as copper, aluminum, iron, or nickel. The current collector plate 30 is aligned with the plurality of power storage devices 10 in a third direction (along a third axis) that is perpendicular to the first direction and the second direction.

[0023] The row of the power storage devices 10 is positioned in a zigzag pattern, and the current collector plates 30 also extend horizontally in a zigzag pattern corresponding to this. The row of the power storage devices 10 does not necessarily have to be zigzag. In the figure, the planar shape of each power storage device 10 is shown by a dashed line. Although the power storage devices are positioned in a zigzag pattern in this disclosure, they are generally lined up in one direction, so multiple power storage devices lined up in a zigzag pattern can also be considered to be lined up in one direction.

[0024] The base of the current collecting plate 30 has a shape in which rectangular unit areas 32 are connected so as to cover most of the upper end of one of the power storage devices 10, but does not cover a portion of the negative electrode terminal 24 located on the periphery of the corresponding power storage device 10. In the drawing, the base of the current collecting plate 30 is shifted downward in the drawing with respect to the upper end surface of the corresponding power storage device 10, and the upper portion in the drawing of the negative electrode terminal 24 of the corresponding power storage device 10 is exposed. Note that the base of the current collecting plate 30 may also cover the power storage devices in the second row.

[0025] A substantially circular opening 34 is formed in the unit area 32 (base) of the current collector plate 30 at a position corresponding to the positive terminal 22 of the power storage device 10. A long, thin positive electrode lead 36 extends in a U-shape from the inner peripheral edge (right side) of the opening 34, and its tip is connected to the positive electrode terminal 22 of the power storage device 10. Here, the positive electrode is referred to as the first electrode, the negative electrode is referred to as the second electrode, the positive electrode lead 36 is referred to as the first lead, and the negative electrode lead 38 is referred to as the second lead.

[0026] In the illustrated example, the tip of the positive electrode lead 36 is widened into a square shape, and this portion is connected to the positive electrode terminal 22 of the energy storage device 10. In Fig. 3, the connection point between the energy storage device 10 and the positive electrode lead 36 is indicated by a black circle. This connection is made by spot welding, for example. The positive electrode lead 36 also has an elongated U-shape, and its elasticity allows the tip portion to be pressed against the positive electrode terminal 22.

[0027] Furthermore, at the base of the current collector plate 30, from a position offset in the first direction from the U-shaped root portion (first connection portion) of the positive electrode lead 36, the negative electrode lead 38 extends in an L-shape downward in FIG. 3 . The tip of the negative electrode lead 38 has a slightly wider rectangular shape and is connected to the negative electrode terminal 24 of the energy storage device 10 in the next row. In the illustrated example, the negative electrode lead 38 is formed by a pair of slits (or only one slit) extending upward from the lower end of the current collector plate 30 in FIG. 3 , and is composed of a slender plate-like portion and a portion (bent in the first direction) extending downward from the current collector plate 30 in FIG. 3 . The tip portion of the negative electrode lead 38 reaches above the negative electrode terminal 24 of the energy storage device 10 and is connected. The negative electrode lead 38 may also be pressed against the negative electrode terminal of the energy storage device 10 due to its elasticity.

[0028] In such a current collector plate 30, the positive electrodes of the power storage devices 10 in the first row and the negative electrodes of the power storage devices 10 in the second row are connected in parallel, and all of the power storage devices 10 in the first row have the same potential.

[0029] However, in the current collector plate 30 of this embodiment, the positive electrodes of the energy storage devices 10 in the first column are connected to the negative electrodes of the energy storage devices 10 in the second column. The energy storage devices 10 output current from their positive electrodes and receive current from their negative electrodes. Therefore, in the current collector plate 30, current flows from the positive electrode lead 36 to the negative electrode lead 38. In the current collector plate 30 of this embodiment, current flows from the base of the positive electrode lead 36 (first connection portion 36a) to the base of the negative electrode lead 38 (second connection portion 38a). In other words, current flows from the positive electrode leads connected to the first energy storage device 10a, the second energy storage device 10b, and the fifth energy storage device 10e arranged in the first column to the negative electrode leads connected to the third energy storage device 10c, the fourth energy storage device 10d, and the energy storage devices 10 arranged in the second column (see FIG. 1 ). In the first direction, in the first column, the first storage device, the second storage device, and the storage device 10 are arranged adjacent to each other from the first end to the second end, respectively. In the second column, the third storage device 10c, the fourth storage device 10d, and the sixth storage device are arranged adjacent to each other from the first end to the second end, respectively. As unit areas, current flows from the first storage device to the third storage device, from the second storage device to the fourth storage device, and from the fifth storage device to the sixth storage device. Because the current collector plate 30 has non-zero electrical resistance, a voltage drop occurs when current flows from the first connection portion 36a to the second connection portion 38a arranged in the first direction. That is, a voltage drop occurs between the base of the positive electrode lead 36 and the base of the negative electrode lead 38 due to the current flowing in the first direction, and a potential difference occurs in the first direction in each unit area 32 of the base.

[0030] In this embodiment, in adjacent unit areas 32, the positions of the root (first connection portion 36 a) of the positive electrode lead 36 and the root (second connection portion 38 a) of the negative electrode lead 38 are inverted with respect to the axis extending in the second direction, and their arrangements and shapes in the first direction are reversed. In adjacent unit areas 32, currents flow alternately in one direction and in the opposite direction. Specifically, in the first direction, adjacent pairs of first connection portions are arranged side by side in the first direction between adjacent second connection portions. Alternatively, adjacent pairs of first connection portions are arranged side by side in the first direction between adjacent second connection portions. Furthermore, in a case where there are three unit areas, when adjacent pairs of first connection portions are arranged side by side in the first direction between adjacent second connection portions in adjacent first and second unit areas, adjacent pairs of first connection portions are arranged side by side in the first direction between adjacent second connection portions in the second unit area and a third unit area adjacent to the second unit area. Therefore, even if a voltage drop of ΔV occurs in one unit area 32, a voltage drop of −ΔV occurs in the adjacent unit area 32, making it possible to reduce the lateral potential difference in the current collector plate 30 and suppress potential variations among multiple power storage devices connected in parallel. Note that in the power storage module disclosed herein, it is not necessary for the arrangement of all first connection parts and second connection parts on one current collector plate to satisfy the above requirements; it is sufficient that some of the first connection parts and some of the second connection parts out of all the first connection parts and second connection parts satisfy the above requirements.

[0031] 4 is a diagram showing the configuration of a comparative example. In this comparative example, in all unit areas 32, the roots of the positive electrode leads 36 are located on the right side, and the roots of the negative electrode leads 38 are located on the left side. With this configuration, the voltage drop ΔV in the first direction in one unit area is added from one end to the other end of the current collector plate 30. For example, in a current collector plate 30 to which n unit areas are connected, a potential difference of n*ΔV occurs between one end and the other end. In this case, potential variations increase among the parallel-connected power storage devices, which can reduce the reliability of the power storage module.

[0032] In the present embodiment, such a potential difference can be alleviated. In an experiment using a current collector 30 in which 10 unit areas were connected, a potential difference of about 24.7 mV occurred in the comparative example, but in the present embodiment, this was reduced to about 2.9 mV, a significant improvement.

[0033] REFERENCE SIGNS LIST 10 Energy storage device 10a First energy storage device 10b Second energy storage device 10c Third energy storage device 10d Fourth energy storage device 10e Fifth energy storage device 10f Sixth energy storage device 22 Positive electrode terminal (first electrode) 24 Negative electrode terminal (second electrode) 30 Current collector plate 32 Unit area (base) 34 Opening 36 Positive electrode lead (first lead) 36a First connection portion 38 Negative electrode lead (second lead) 38a Second connection portion 100 Energy storage module 101 Energy storage device group (first energy storage device group) 102 Energy storage device group (second energy storage device group) 103 Energy storage device group

Claims

1. A power storage module comprising: a plurality of power storage devices each having a first electrode and a second electrode; and a current collector plate for electrically connecting the plurality of power storage devices to each other, wherein the plurality of power storage devices include a first power storage device group arranged in a first direction and a second power storage device group arranged in the first direction, the first power storage device group and the second power storage device group are arranged in a second direction orthogonal to the first direction, the current collector plate connects each of the plurality of first electrodes of the first power storage device group in parallel, and connects each of the plurality of first electrodes of the first power storage device group in series to a corresponding one of the plurality of second electrodes of the second power storage device group, the current collector plate has a base portion, a plurality of first leads extending from the base portion and connected to the plurality of first electrodes of the first power storage device group, a plurality of second leads extending from the base portion and connected to the plurality of second electrodes of the second power storage device group, a plurality of first connection portions connecting the plurality of first leads and the base portion, and a plurality of second connection portions connecting the plurality of second leads and the base portion, and a pair of first connection portions among the plurality of first connection portions are arranged between a pair of second connection portions adjacent to each other in the first direction among the plurality of second connection portions, and the pair of first connection portions are arranged side by side in the first direction.

2. The first battery storage device group includes a first battery storage device and a second battery storage device arranged in the first direction. The second battery storage device group includes a third battery storage device and a fourth battery storage device arranged in the first direction. The plurality of first leads connect the first poles of the first battery storage device and the second battery storage device in parallel. The first pole of the first battery storage device is connected in series with the second pole of the third battery storage device. The first pole of the second battery storage device is connected in series with the second pole of the fourth battery storage device. The first battery storage device is arranged closer to the first end of the first battery storage device group than the second battery storage device. The second battery storage device is arranged closer to the second end of the first battery storage device group than the first battery storage device. The third battery storage device is arranged closer to the first end of the second battery storage device group than the fourth battery storage device. The fourth battery storage device is arranged closer to the second end of the second battery storage device group than the third battery storage device. In the first direction, the first connection portion of the first lead connected to the first battery storage device among the plurality of first leads and the first connection portion of the first lead connected to the second battery storage device among the plurality of first leads are arranged between the second connection portion of the second lead connected to the third battery storage device among the plurality of second leads and the second connection portion of the second lead connected to the fourth battery storage device among the plurality of second leads. The battery storage module according to claim 1.

3. The current collector plate has a plurality of openings that expose the plurality of first poles of the first battery storage device group. Each of the plurality of first connection portions of the plurality of first leads is formed on the inner edge of a corresponding one of the plurality of openings. The battery storage module according to claim 1.

4. The current collector plate and the plurality of battery storage devices are arranged in a third direction orthogonal to the first direction and the second direction. The first poles of each of the plurality of battery storage devices and the second poles of each of the plurality of battery storage devices are connected to the current collector plate on one end side of the battery storage module in the third direction. The battery storage module according to claim 1.

5. The first power storage device group further includes a fifth power storage device disposed closer to the second end of the first power storage device group than the second power storage device. The second power storage device group further includes a sixth power storage device disposed closer to the second end of the second power storage device group than the fourth power storage device. In the first direction, the second connection portion of the second lead connected to the fourth power storage device among the plurality of second leads and the second connection portion of the second lead connected to the sixth power storage device among the plurality of second leads are located between the first connection portion of the first lead connected to the second power storage device among the plurality of first leads and the first connection portion of the first lead connected to the fifth power storage device among the plurality of first leads. The power storage module according to claim 2.

6. Among the plurality of first leads, the pair of first leads connected to the pair of first connection portions have portions extending in opposite directions to each other in the first direction. The power storage module according to claim 1.

7. Among the plurality of second leads, the pair of second leads connected to the pair of second connection portions have portions extending in opposite directions to each other in the first direction. The power storage module according to claim 1.

8. A power storage module comprising: a plurality of power storage devices each having a first electrode and a second electrode; and a current collecting plate for electrically connecting the plurality of power storage devices to each other, wherein the plurality of power storage devices include a first power storage device group arranged in a first direction and a second power storage device group arranged in the first direction, the first power storage device group and the second power storage device group are arranged side by side in a second direction orthogonal to the first direction, the current collecting plate connects each of the plurality of first electrodes of the first power storage device group in parallel, and each of the plurality of first electrodes of the first power storage device group is connected in series to a corresponding one of the plurality of second electrodes of the second power storage device group. The current collecting plate has a base portion, a plurality of first leads extending from the base portion and connected to the plurality of first electrodes of the first power storage device group, a plurality of second leads extending from the base portion and connected to the plurality of second electrodes of the second power storage device group, a plurality of first connection portions where the plurality of first leads are connected to the base portion, and a plurality of second connection portions where the plurality of second leads are connected to the base portion. A pair of second connection portions among the plurality of second connection portions are arranged between a pair of first connection portions adjacent to each other in the first direction among the plurality of first connection portions, and the pair of second connection portions are arranged side by side in the first direction.

9. The current collecting plate has a plurality of openings for exposing the plurality of first electrodes of the first power storage device group, and each of the plurality of first connection portions of the plurality of first leads is formed on an inner edge of a corresponding one of the plurality of openings. The power storage module according to claim 8.

10. The current collecting plate and the plurality of power storage devices are arranged side by side in a third direction orthogonal to the first direction and the second direction, and each of the first electrodes of the plurality of power storage devices and each of the second electrodes of the plurality of power storage devices are connected to the current collecting plate on one end side of the power storage module in the third direction. The power storage module according to claim 8.

11. Among the plurality of first leads, the pair of first leads connected to the pair of first connection portions have portions extending in opposite directions to each other in the first direction. The power storage module according to claim 8.

12. The power storage module according to claim 8, wherein, among the plurality of second leads, a pair of second leads connected to the pair of second connection portions have portions extending in opposite directions to each other in the first direction.

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