Power supply device, electric vehicle equipped with the power supply device, and power storage device

Abstract

A power supply device that comprises: a battery block (10) that is formed by layering a plurality of battery cells (1) in the thickness direction with a separator (2) therebetween; a pair of end plates (3) that are arranged on either end surface of the battery block (10); and a binding bar (4) that is connected to the pair of end plates (3) and fixes the battery block (10) in a pressurized state via the end plates (3). The separator (2) is an uneven layer (25) that comprises an elastomer and is configured such that either surface of a plate-shaped part (20) responds to pressing force with a different change in thickness.

Description

[Technical field]

[0001] The present invention relates to a power supply device in which many battery cells are stacked, and an electric vehicle and a power storage device equipped with this power supply device. [Background technology]

[0002] Power supply devices with many stacked battery cells are suitable as power sources mounted on electric vehicles to supply power to the motor that runs the vehicle, as power sources charged with natural energy such as solar cells or overnight power, and as backup power sources during power outages. Power supply devices with this structure have separators sandwiched between the stacked battery cells. Power supply devices in which many battery cells are stacked with separators sandwiched between them fix the stacked battery cells in a pressurized state to prevent displacement due to battery cell expansion. To achieve this, the power supply device has a pair of end plates disposed on both end faces of a battery block in which many battery cells are stacked, and the pair of end plates are connected by a bind bar. (See Patent Document 1) [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-204708 A Summary of the Invention [Problem to be solved by the invention]

[0004] The power supply unit stacks multiple battery cells to form a battery block, and a pair of end plates are placed on both end faces of the battery block, which are held in a pressurized state with a fairly strong pressure from both ends and connected with a bind bar. The power supply unit fixes the battery cells under strong pressure to prevent malfunctions due to relative movement or vibration of the battery cells. For example, this power supply unit can be used with a stacked surface area of ​​about 100 cm2. 2In a device that uses battery cells having the above structure, the end plates are pressed with a strong force of several tons and fixed with a bind bar. In a power supply device with this structure, adjacent stacked battery cells are insulated by separators, and plate-shaped insulating plastic plates are used for the separators. When the internal pressure of the battery cells increases and they expand, the plastic plate separators cannot absorb the expansion of the battery cells, and in this state the surface pressure between the battery cells and the separators increases suddenly, and extremely strong forces are applied to the end plates and bind bars. For this reason, the end plates and bind bars are required to be made of extremely strong materials and shapes, which has the disadvantages of making the power supply device heavy and large, as well as increasing material costs.

[0005] The present invention was developed with the objective of eliminating the above-mentioned drawbacks, and one of the objects of the present invention is to provide a technique for absorbing expansion of a battery cell with a separator. [Means for solving the problem]

[0006] A power supply device according to one aspect of the present invention includes a battery block formed by stacking multiple battery cells in the thickness direction with separators sandwiched between them, a pair of end plates disposed on both end faces of the battery block, and a bind bar connected to the pair of end plates and fixing the battery block in a pressurized state via the end plates. The separator is made of an elastomer, and both sides of the plate-shaped portion are formed as uneven layers with different amounts of change in thickness in response to a pressing force.

[0007] An electric vehicle according to one embodiment of the present invention comprises the above-mentioned power supply device, a motor for driving that is supplied with power from the power supply device, a vehicle body equipped with the power supply device and the motor, and wheels driven by the motor to drive the vehicle body.

[0008] An energy storage device according to one embodiment of the present invention includes the above-mentioned power supply device and a power supply controller that controls charging and discharging to the power supply device, and the power supply controller enables charging of the battery cells using external power and controls the charging of the battery cells. Effect of the Invention

[0009] In the power supply device described above, the parallel ridges of the separator locally press against the electrode layers of the battery cells, suppressing battery deterioration due to a decrease in the fluidity of the electrolyte. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a power supply device according to an embodiment of the present invention; [Diagram 2] 2 is a vertical sectional view of the power supply device shown in FIG. 1. [Diagram 3] 2 is a horizontal sectional view of the power supply device shown in FIG. 1. [Figure 4] FIG. 2 is a partially enlarged cross-sectional view showing the stacked structure of the battery cells and separators. [Diagram 5] FIG. 4 is a partially enlarged cross-sectional view showing another example of a separator. [Figure 6] FIG. 4 is a partially enlarged cross-sectional view showing another example of a separator. [Figure 7] FIG. 2 is an exploded perspective view showing the stacked structure of battery cells and separators. [Figure 8] FIG. 8 is a rear perspective view of the battery cell and separator shown in FIG. 7. [Figure 9] FIG. 11 is an enlarged cross-sectional view of a main portion showing the state in which the surface of an expanding battery cell is pressed by parallel ridges and deformed into a wavy shape. [Figure 10] FIG. 4 is a perspective view showing another example of a separator. [Figure 11] FIG. 11 is a rear perspective view of the separator of FIG. [Figure 12] FIG. 11 is an exploded perspective view showing another example of a stacked structure of battery cells and separators. [Figure 13] 1 is a block diagram showing an example of a power supply device mounted on a hybrid vehicle that runs on an engine and a motor. [Figure 14] FIG. 1 is a block diagram showing an example in which a power supply device is mounted on an electric vehicle that runs only on a motor. [Figure 15] FIG. 11 is a block diagram showing an example of application to a power supply device for power storage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", and other terms including these terms) are used as necessary, but the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meanings of these terms do not limit the technical scope of the present invention. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members. Furthermore, the embodiments shown below are specific examples of the technical ideas of the present invention, and do not limit the present invention to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention. Furthermore, the contents described in one embodiment or example can be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0012] The power supply device of the first embodiment of the present invention includes a battery block formed by stacking multiple battery cells in the thickness direction with separators sandwiched between them, a pair of end plates arranged on both end faces of the battery block, and a bind bar connected to the pair of end plates and fixing the battery block in a pressurized state via the end plates. The separator is made of an elastomer, and both sides of the plate-shaped portion are made into uneven layers with different amounts of change in thickness in response to pressing force.

[0013] The separator of the power supply device described above has different thickness changes in response to pressure, i.e., an uneven layer that flexibly changes when pressed by the battery cell and an uneven layer that changes little are provided on both sides, so that in areas where the expansion of the battery cell is small, the flexible uneven layer that is easily deformed absorbs the expansion, and when the expansion of the battery cell becomes large and the flexible uneven layer is crushed and cannot absorb the expansion, the uneven layer that is less likely to deform absorbs the expansion, and further, when the expansion of the battery cell becomes large and the uneven layer that is less likely to deform is also crushed and cannot absorb the expansion, the plate-like portion deforms thinly to absorb the expansion of the battery cell. When the uneven layer is crushed and further pressurized, the plate-like portion of the separator deforms thinly to absorb the expansion of the battery cell. The elastomer plate-like portion is less likely to deform than the uneven layer, and the uneven layer elastically deforms under strong pressure that exceeds its elastic limit, further absorbing the expansion of the battery cell. For this reason, in a separator having uneven layers on both sides of the plate-shaped portion that have different amounts of change in thickness in response to pressure, small expansion of the battery cells is absorbed by the easily deformed uneven layer, larger expansion is absorbed by the less deformed uneven layer, and even larger expansion is absorbed by the plate-shaped portion being crushed thin. Therefore, the above separator has the advantage that it can absorb small expansion of the battery cells, which occurs frequently, with the uneven layer, large expansion is absorbed by the plate-shaped portion, and intermediate expansion between small and large expansion of the battery cells is absorbed by the less deformed uneven layer, so that it can absorb a wide range of battery cell expansion in an ideal state. The easily deformed uneven layer is also expected to have the effect of absorbing dimensional tolerances of the battery cells and the separator.

[0014] Furthermore, the power supply device described above has uneven layers with different deformation amounts on both sides of the elastomer plate-like portion, and the three elastic deformation layers with different deformation amounts against the pressing force suppress the increase in surface pressure due to the expansion of the battery cells, so that the battery cells can efficiently absorb the expansion while mitigating the stress acting on the end plates and the bind bars. The uneven layer can efficiently absorb the initial expansion of the battery cells, but when the expansion of the battery cells increases and exceeds the elastic limit, it is no longer possible to elastically deform, causing the stress on the end plates and the bind bars to increase rapidly. However, in the region where the uneven layer exceeds the elastic limit, the elastomer plate-like portion elastically deforms and suppresses the increase in stress on the end plates and the bind bars. Therefore, the maximum stress acting on the end plates and the bind bars can be suppressed while effectively absorbing the expansion of the battery cells. A power supply device that can suppress the maximum stress acting on the end plates and the bind bars can be made thinner and lighter by using thinner end plates and bind bars.

[0015] In addition, a power supply device in which a three-layer elastic deformation layer consisting of uneven layers on both sides and plate-shaped portions effectively absorbs the expansion of the battery cells can prevent the battery cells from shifting relative to one another due to their expansion. This also prevents problems with the electrical connections of the battery cells. The stacked battery cells are electrically connected by fixing metal bus bars to the electrode terminals, but if the battery cells shift relative to one another, excessive stress is applied to the bus bars and electrode terminals, causing failure.

[0016] In the power supply device according to the second embodiment of the present invention, the elastomer of the separator is synthetic rubber.

[0017] In the power supply device according to the third embodiment of the present invention, the synthetic rubber of the elastomer is selected from the group consisting of fluororubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprone rubber, nitrile rubber, hydrogenated nitrile rubber, P The rubber may be any of the following: triisobutylene rubber, ethylene propylene rubber, ethylene vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, silicone rubber, thermoplastic olefin rubber, ethylene propylene diene rubber, butyl rubber, and polyether rubber.

[0018] In the power supply device according to the fourth embodiment of the present invention, the separator has a plurality of protrusions on the surface of the plate-shaped portion to form an uneven layer.

[0019] In the power supply device according to the fifth embodiment of the present invention, convex portions of different shapes are provided on both sides of a plate-shaped portion, forming an uneven layer with a different amount of change in thickness in response to a pressing force from a battery cell.

[0020] A power supply device according to a sixth embodiment of the present invention has protrusions on both sides of a plate-shaped portion, the protrusions having different contact areas with the battery cells when in an uncompressed state.

[0021] In the power supply device of the seventh embodiment of the present invention, the concave-convex layer has convex portions whose cross-sectional area in a plane parallel to the surface of the plate-shaped portion increases from the portion in contact with the battery cell toward the plate-shaped portion.

[0022] In the power supply device according to the eighth embodiment of the present invention, the protrusions are elongated ridges, and multiple rows of ridges are provided on the surface of the plate-shaped portion.

[0023] A power supply device according to a ninth embodiment of the present invention has parallel ridges formed by arranging multiple rows of ridges parallel to one another, and the uneven layer has multiple rows of parallel ridges and multiple rows of parallel grooves arranged alternately.

[0024] In the power supply device described above, the parallel ridges of the separator locally press against the electrode layer of the battery cell, improving the fluidity of the electrolyte. A comb-shaped separator with alternating parallel ridges and parallel grooves on the surface facing the battery cell improves the fluidity of the electrolyte because the electrodes become highly dense in the areas pressed by the parallel ridges, but become less dense in the areas facing the parallel grooves that are not pressed by the parallel ridges, making it easier for the electrolyte to move.

[0025] In the power supply device of the tenth embodiment of the present invention, a first uneven layer of a plate-shaped portion is provided with parallel ridges having a rectangular cross-sectional shape, and a second uneven layer of the plate-shaped portion is provided with parallel ridges whose width gradually narrows toward the battery cell connection surface, thereby providing uneven layers on both sides of the plate-shaped portion with different amounts of change in thickness in response to a pressing force. In this specification, the cross section of a parallel ridge means a cross section in a cut surface perpendicular to the longitudinal direction of the parallel ridge.

[0026] In the power supply device of the eleventh embodiment of the present invention, the second uneven layer of the plate-shaped portion is provided with parallel ridges whose cross-sectional shape is any one of triangular, arched, and trapezoidal.

[0027] (Embodiment 1) A power supply device 100 shown in the oblique view of Figure 1, the vertical cross-sectional view of Figure 2, and the horizontal cross-sectional view of Figure 3 comprises a battery block 10 in which multiple battery cells 1 are stacked in the thickness direction with separators 2 sandwiched between them, a pair of end plates 3 arranged on both end faces of the battery block 10, and a bind bar 4 that connects the pair of end plates 3 and fixes the battery block 10 in a pressurized state via the end plates 3.

[0028] (Battery block 10) The battery block 10 is formed by stacking multiple battery cells 1, which are rectangular battery cells with an external shape of a rectangle, in the thickness direction with separators 2 sandwiched between them. The multiple battery cells 1 are stacked so that their upper surfaces are flush with each other to form the battery block 10.

[0029] (Battery cell 1) As shown in Fig. 4, the battery cell 1 has an internally sealed structure in which electrodes 15 are inserted into a battery case 11 whose bottom is closed, and a sealing plate 12 is laser-welded to the upper opening to airtightly secure it. Furthermore, the inside of the battery case 11 is filled with an electrolyte (not shown). As shown in Fig. 1, the sealing plate 12 has a pair of positive and negative electrode terminals 13 that protrude upward from both ends of the upper surface. A safety valve 14 is provided between the electrode terminals 13. The safety valve 14 opens when the internal pressure of the battery cell 1 rises to or above a predetermined value, thereby releasing the internal gas. The safety valve 14 prevents the internal pressure of the battery cell 1 from increasing.

[0030] The battery cell 1 is a lithium ion secondary battery. The power supply device 100, which uses a lithium ion secondary battery as the battery cell 1, has the feature of being able to increase the charging capacity relative to the capacity and weight. However, the battery cell 1 can be any other rechargeable battery, such as a non-aqueous electrolyte secondary battery other than a lithium ion secondary battery.

[0031] (3 end plates, 4 bind bars) The end plates 3 are metal plates with an outline roughly equal to the outline of the battery cells 1 so that they do not deform when pressed by the battery block 10, and have bind bars 4 connected to their opposite edges. The bind bars 4 connect the stacked battery cells 1 with the end plates 3 in a pressurized state, and fix the battery block 10 in a pressurized state at a specified pressure.

[0032] (Separator 2) Separators 2 are sandwiched between stacked battery cells 1 to absorb expansion of the battery cells 1 due to an increase in internal pressure and also insulate adjacent battery cells 1. A battery block 10 connects the battery cells 1 in series or parallel by fixing bus bars (not shown) to the electrode terminals 13 of adjacent battery cells 1. Battery cells 1 connected in series are stacked and insulated with separators 2 because a potential difference occurs in the battery case. Battery cells 1 connected in parallel do not generate a potential difference in the battery case 11, but are stacked and insulated with separators 2 to prevent the induction of thermal runaway.

[0033] The separator 2, which is pressed against the battery cell 1 and elastically deforms, is made of an elastomer. The elastomer of the separator 2 is a rubber-like elastic body with a hardness of, for example, A30 to A90 degrees, so that it is elastically deformed when pressed against the battery cell 1. Synthetic rubber is suitable for the elastomer of the separator 2. Examples of synthetic rubber include fluororubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroproene rubber, nitrile rubber, hydrogenated nitrile rubber, P Any of the following synthetic rubber sheets can be used alone or in combination: isobutylene rubber, ethylene propylene rubber, ethylene vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, silicone rubber, thermoplastic olefin rubber, ethylene propylene diene rubber, butyl rubber, and polyether rubber. In particular, ethylene propylene rubber, ethylene vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, fluororubber, and silicone rubber have excellent heat insulating properties, so that high safety can be achieved until the temperature of the battery cell 1 rises to a high temperature. In addition, it is preferable to use thermoplastic polyurethane rubber or foamed polyurethane rubber for the separator 2, which uses urethane rubber as the elastomer.

[0034] The separator 2 can easily absorb the expansion of the battery cell 1 and reduce the maximum stress on the end plates 3 and the bind bars 4. An ideal separator 2 for absorbing the expansion of the battery cell 1 is one that not only effectively absorbs small expansions of the battery cell 1, but also absorbs large expansions, suppressing the maximum stress on the end plates 3 and the bind bars 4. A separator 2 that achieves this characteristic has the following characteristics: Rising As the pressure gradually increases, the battery pack must be able to quickly elastically deform and absorb the expansion smoothly in areas where the expansion of the battery cell 1 is relatively small, and it must also be able to deform and absorb the expansion without exceeding its elastic limit even when the expansion of the battery cell 1 reaches its maximum.

[0035] Since elastomers are elastically deformed, they can absorb the expansion of the battery cell 1 as a single plate-shaped separator 2. This separator 2 is made of an elastomer with a small Young's modulus and can easily absorb small expansions of the battery cell 1. However, when the expansion of the battery cell 1 reaches its maximum range and the pressing force becomes strong, the separator 2 exceeds its elastic limit and is no longer able to easily absorb the expansion. If the separator 2 is made of an elastomer with a large Young's modulus in order to increase the pressure of the elastic limit of the separator 2, it will not be able to smoothly absorb small expansions of the battery cell 1. The expansion of the battery cell 1 is determined by external conditions such as the charge and discharge current, and small and large expansions are repeated randomly. Small expansions occur more frequently than large expansions, so the property of being able to smoothly absorb small expansions is extremely important. A separator 2 made of an elastomer with a small Young's modulus that can easily absorb small expansions that occur frequently has a low elastic limit and cannot stably absorb large expansions in the maximum range. If the separator 2 is no longer able to absorb the large expansion of the maximum area of ​​the battery cell 1, the pressure applied by the battery cell 1 to the separator 2 increases, causing the internal stress in the end plate 3 and the bind bar 4 to increase significantly.

[0036] 4 to 6 has a plurality of protrusions 23 on the surface of the plate-shaped portion 20 to form an uneven layer 25 in order to smoothly absorb small expansions of the battery cells 1 while increasing the elastic limit to absorb large expansions of the battery cells 1. The separator 2 shown in these figures has protrusions 23 of different shapes on both sides to form an uneven layer 25 with different amounts of thickness change in response to a pressing force from the battery cells 1. The uneven layer 25 on both sides of the plate-shaped portion 20 has protrusions 23 with different contact areas with the battery cells 1 in an uncompressed state, as shown in the figures, to form an uneven layer 25 with different amounts of thickness change in response to a pressing force.

[0037] In these figures, separator 2 has first uneven layer 25A on one surface (the left side in the figures) of plate-shaped portion 20 and second uneven layer 25B on the other surface (the right side in the figures), with second uneven layer 25B having a larger amount of displacement in response to a pressing force than first uneven layer 25A, i.e., a structure that easily absorbs small expansion of battery cells 1. In separator 2 shown in these figures, protrusions 23A provided on first uneven layer 25A have a rectangular cross-sectional shape, and protrusions 23B, 23C, 23D provided on second uneven layer 25B have a shape in which the cross-sectional area in a plane parallel to the plate-shaped portion surface increases from the contact portion with battery cell 1 toward plate-shaped portion 20. In the separator 2 of FIG. 4, the cross-sectional shape of the convex portion 23B of the second uneven layer 25B is semicircular or arched, in the separator 2 of FIG. 5, the cross-sectional shape of the convex portion 23C of the second uneven layer 25B is triangular, and in the separator 2 of FIG. 6, the cross-sectional shape of the convex portion 23D of the second uneven layer 25B is trapezoidal, which is a shape that is easier to deform than the quadrangular convex portion 23A of the first uneven layer 25A, which is rectangular.

[0038] The separator 2 shown in the perspective views of Figs. 7 and 8 has multiple rows of protrusions on the surface of the plate-shaped portion 20, with the protrusions 23 of the uneven layer 25 being elongated protrusions. Furthermore, the separator 2 shown in the figures has multiple rows of protrusions on the uneven layer 25 arranged parallel to each other as parallel protrusions 21, with parallel grooves 22 provided between the multiple rows of parallel protrusions 21, so that the parallel protrusions 21 and the parallel grooves 22 are arranged alternately. In this separator 2, the multiple rows of parallel protrusions 21 locally press against the expanding battery cell surface, and the parallel protrusions 21 elastically deform to absorb the expansion of the battery cell 1. In the separator 2, the parallel protrusions 21 provided on the first uneven layer 25A and the second uneven layer 25B have cross-sectional shapes shown in Figs. 4 to 6, and the first uneven layer 25A and the second uneven layer 25B optimize the amount of deformation in response to the pressing force of the battery cell 1.

[0039] In the separator 2, in areas where the expansion of the battery cell 1 is small, the parallel ridges 21A of the first uneven layer 25A hardly deform and the parallel ridges 21B of the second uneven layer 25B elastically deform to absorb the expansion of the battery cell 1, and when the expansion of the battery cell 1 increases and the parallel ridges 21B of the second uneven layer 25B are almost crushed, the parallel ridges 21A of the first uneven layer 25A elastically deform to absorb the expansion of the battery cell 1. When the expansion of the battery cell 1 increases further and the parallel ridges 21A of the first uneven layer 25A are almost crushed, the plate-shaped portion 20 elastically deforms to absorb the expansion of the battery cell 1.

[0040] When the battery cell 1 is pressed by the parallel ridges 21, the areas pressed by the parallel ridges 21 become recessed, and the areas facing the parallel grooves 22 protrude and are deformed into a corrugated shape. The enlarged cross-sectional view of a main part in FIG. 9 exaggerates the state in which the surface of the battery cell 1 is pressed by the parallel ridges 21 and deformed into a corrugated shape. The battery cell 1 whose surface has been deformed into a corrugated shape deforms the surface of the laminated electrode 15 stored inside the battery case 11 into a corrugated shape. In the laminated electrode 15, areas A that have been pressed into recesses by the multiple rows of parallel ridges 21 have a high density, while protruding areas B that face the parallel grooves 22 have a low density, so that the low-density areas B are generated in a striped pattern, and the low-density areas B improve the fluidity of the electrolyte. Furthermore, the separator 2 described above absorbs the expansion of the battery cell 1 through the elastic deformation of the elastomer, while generating striped low-density regions B in the electrode 15. Therefore, even when the battery cell 1 expands and the fluidity of the electrolyte decreases, the separator 2 has the characteristic of generating striped low-density regions B in the electrode 15, thereby improving the fluidity of the electrolyte.

[0041] The battery cell 1 shown in Figs. 7 and 8 is a prismatic battery in which the stacking surface of the battery case 11 on which the separators 2 are stacked is rectangular, and the positive and negative electrode layers 15a, 15b, which are elongated strips, are wound to form a spiral electrode 15, which is then pressed into a flat plate shape and stored in the battery case 11. The electrode 15 is formed by stacking the positive and negative electrode layers 15a, 15b, which are elongated strips, with an insulating sheet 15c sandwiched between them, and then rolling them up to form the spiral electrode 15. The spiral electrode 15 is then pressed into a flat shape and stored in the prismatic battery case 11. As shown in the figures, the elastomer separator 2 has parallel ridges 21 and parallel grooves 22 arranged in a position that extends in the width direction of the strip-shaped positive and negative electrode layers 15a, 15b. In this separator 2, the parallel ridges 21 are arranged parallel to the extension direction of the U-shaped portion 15A of the spiral electrode 15, and high density regions A and low density regions B extending in the width direction of the electrode layers 15a, 15b are formed in a striped pattern on the surface of the electrode 15. This allows the high density regions A and low density regions B to be naturally provided in a striped pattern on the spiral electrode 15, thereby improving the fluidity of the electrolyte.

[0042] The width (W1) and height (h) of the parallel ridges 21 and the opening width (W2) of the parallel grooves 22 are set to dimensions that allow the parallel ridges 21 to press against the surface of the battery case 11 and deform into a corrugated shape, taking into account the hardness of the elastomer. For example, in a separator 2 with an elastomer hardness of A30 degrees to A90 degrees, the width (W1) of the bottom of the parallel ridges 21, i.e., the boundary region with the plate-shaped portion 20, is set to 1 mm or more and 20 mm or less, preferably 2 mm or more and 10 mm or less, so that the parallel ridges 21B of the second uneven layer 25B, which is easily deformed, can be deformed into a corrugated shape. In the separator 2 of Figs. 7 and 8, the width (W1) of the parallel ridges 21B of the second uneven layer 25B, which is easily deformed, is narrower than the width (W1) of the parallel ridges 21A of the first uneven layer 25A, which is less easily deformed. The height (h) of the parallel ridge 21 is, for example, 0.1 mm or more and 2 mm or less, preferably 0.2 mm or more and 1.5 mm or less, the opening width (W2) of the parallel groove 22 is 1 mm or more and 20 mm or less, preferably 2 mm or more and 10 mm or less, and the ratio (W1 / W2) of the width (W1) of the parallel ridge 21 to the opening width (W2) of the parallel groove 22 is 0.1 or more and 10 or less, preferably 0.5 or more and 2 or less.

[0043] The elastomer separator 2 can absorb the expansion of the battery case 11 to a greater extent by increasing the height (h) of the parallel ridges 21 and widening the opening width (W2) of the parallel grooves 22. However, if the parallel ridges 21 are too high, the separator becomes thick and is prone to buckling, so the height (h) of the parallel ridges 21 is set to the above range, taking into consideration the allowable thickness of the separator 2 and the ability to locally press the battery case 11 and deform it into a waveform. In addition, the opening width (W2) of the parallel grooves 22 and the ratio (W1 / W2) of the horizontal width (W1) of the parallel ridges 21 to the opening width (W2) of the parallel grooves 22 specify the pitch at which the surface of the battery case 11 is deformed into a waveform, and are therefore set to the above range, taking into consideration the favorable fluidity of the electrolyte while supporting the expansion of the battery cell 1 with the multiple rows of parallel ridges 21. For example, the battery cell 1 is a rectangular lithium ion battery, the battery case 11 is an aluminum plate with a thickness of 0.3 mm, and the area of ​​the separator laminate surface is 100 cm 2In a power supply device 100 having a width (W1) of the parallel ridges 21 and an opening width (W2) of the parallel grooves 22 of 5 mm, a height (h) of the parallel ridges 21 of 0.5 mm, an elastomer hardness of A60 degrees, and 12 stacked battery cells 1, when the battery cells 1 expand, the surface facing the separator 2 deforms into a wavy shape, improving the fluidity of the electrolyte.

[0044] In order to miniaturize the battery block 10 and increase the charging capacity of the power supply device 100, it is important to make the separator 2 thin to absorb the expansion of the battery cells 1. For this reason, the elastomer separator 2 should have a thickness (d) of, for example, 2 mm or more and 8 mm or less, and more preferably 1.5 mm or more and 5 mm or less.

[0045] The separator 2 shown in Figures 7 and 8 has multiple rows of parallel ridges 21 extending in the width direction of the battery cell 1 (horizontal direction in the figures) with a total length that is approximately equal to the width of the battery cell 1, and is structured so that the multiple rows of parallel ridges 21 extending in parallel stripes press against the opposing surfaces of the battery cell 1. Furthermore, as shown in Figures 10 and 11, the separator 2 can also have multiple parallel ridges 21 extending in the longitudinal direction. The separator 2 shown in Figures 10 and 11 has a cutout portion 24 provided in the middle of the parallel ridges 21 to divide one row of parallel ridges 21 into multiple ridges 23. Furthermore, the arrangement of the ridges 23 between adjacent parallel ridges 21 is staggered when viewed from the front. That is, the positions of the convex portions 23 of adjacent parallel convex strips 21 are shifted in the left-right direction so that the convex portion 23 of one parallel convex strip 21 faces the cut portion 24 of the other parallel convex strip 21. The separator 2 shown in the figure has cut portions 24 at both ends of the parallel convex strips 21 in every other row in order to make the convex portions 23 of the adjacent parallel convex strips 21 staggered. This structure in which the divided convex portions 23 are arranged in a staggered pattern has the advantage of being able to evenly distribute the pressure force received from the battery cell 1. However, the divided convex portions can be arranged vertically and horizontally or randomly. The separator 2 having the parallel convex strips 21 of the above shape has the advantage of being more easily elastically deformed than a separator 2 having a structure in which the parallel convex strips 21 are not divided, and can effectively absorb the expansion of the battery cell 1.

[0046] 10 and 11, the ease of elastic deformation of the parallel ridges 21 can be adjusted by adjusting the length (L1) of the ridges 23 and the length (L2) of the cutouts 24. For example, the separator 2 can be made to be more elastically deformable by increasing the ratio (L2 / L1) of the length (L2) of the cutouts 24 to the length (L1) of the ridges 23, and conversely, the ratio (L2 / L1) can be made less elastically deformable. That is, by dividing the parallel ridges 21 into a plurality of parts, the separator 2 is made more easily deformable than a structure in which the parallel ridges 21 are not divided, and the ease of deformation can be further adjusted by adjusting the ratio (L2 / L1). For example, as shown in Figures 10 and 11, the separator 2 can make the second uneven layer 25B more easily deformable by making the ratio (L2 / L1) smaller than the ratio (L2 / L1) of the first uneven layer 25A, thereby enabling the second uneven layer 25B to be deformed reliably with small expansion of the battery cell 1, while suppressing deformation in the first uneven layer 25A, enabling the separator 2 to be deformed reliably with intermediate expansion of the battery cell 1. Furthermore, the ratio (L2 / L1) of the length (L2) of the cutout portion 24 to the length (L1) of the protrusion 23 can be changed depending on the region, even on one surface, i.e., on one uneven layer 25. For example, in the region facing the center portion where the amount of deformation is large when the battery cell 1 expands, the ratio (L2 / L1) can be made large to make it easier to absorb deformation, and in the region facing the outer periphery where the amount of deformation is small when the battery cell 1 expands, the ratio (L2 / L1) can be made small to suppress deformation.

[0047] As shown in Figs. 7 and 8, the above battery cell 1 has the plate-shaped spiral electrode 15 housed in the battery case 11 with its axial direction aligned with the width direction of the battery cell 1. The separator 2 is therefore stacked on the opposing surface of the battery cell 1 with the extension direction of the parallel ridges 21 and parallel grooves 22 aligned with the width direction of the battery cell 1. By stacking the separator 2 so that the parallel ridges 21 and parallel grooves 22 of the separator 2 extend horizontally in the figures, the parallel ridges 21 and parallel grooves 22 can be arranged on the surface of the battery cell 1 so as to be parallel to the axial direction of the spiral electrode 15. As a result, when the battery cell 1 expands, high-density regions and low-density regions extending in the width direction of the electrode layers 15a, 15b are formed in a striped pattern on the surface of the spiral electrode 15, improving the fluidity of the electrolyte.

[0048] However, as shown in FIG. 12, the battery cell 1 can also be housed in the battery case 1 with the plate-shaped spiral electrode 15 so that its axial direction is the height direction of the battery cell 1 and the depth direction of the battery case 11. The separator 2 to be stacked on the battery cell 1 with this structure is stacked on the opposing surface of the battery cell 1 so that the extension direction of the parallel ridges 21 and parallel grooves 22 is the height direction of the battery cell 1. With this structure, by stacking the separator 2 on the battery cell 1 so that the parallel ridges 21 and parallel grooves 22 of the separator 2 are in a position extending in the vertical direction in the figure, the parallel ridges 21 and parallel grooves 2 can be arranged on the surface of the battery cell 1 so that they are parallel to the axial direction of the spiral electrode 15. As a result, when the battery cell 1 expands, high-density regions and low-density regions extending in the width direction of the electrode layers 15a, 15b are formed in a striped pattern on the surface of the spiral electrode 15, improving the fluidity of the electrolyte.

[0049] The power supply device described above can be used as a vehicle power source that supplies power to a motor that runs an electric vehicle. Electric vehicles equipped with the power supply device include hybrid cars and plug-in hybrid cars that run on both an engine and a motor, and electric cars that run only on a motor, and the power supply device is used as a power source for these vehicles. Note that an example will be described in which a large capacity, high output power supply device 100 is constructed by connecting a large number of the above-mentioned power supply devices in series or in parallel to obtain power to drive a vehicle, and further adding necessary control circuits.

[0050] (Power supply unit for hybrid vehicles) FIG. 13 shows an example of a power supply device mounted on a hybrid vehicle that runs on both an engine and a motor. The vehicle HV equipped with the power supply device shown in this figure includes a vehicle body 91, an engine 96 and a motor 93 for running the vehicle body 91, wheels 97 driven by the engine 96 and the motor 93 for running, a power supply device 100 that supplies power to the motor 93, and a generator 94 that charges the battery of the power supply device 100. The power supply device 100 is connected to the motor 93 and the generator 94 via a DC / AC inverter 95. The vehicle HV runs on both the motor 93 and the engine 96 while charging and discharging the battery of the power supply device 100. The motor 93 is driven in an area where the engine efficiency is poor, such as during acceleration or low-speed running, to run the vehicle. The motor 93 is driven by power supplied from the power supply device 100. The generator 94 is driven by the engine 96 or by regenerative braking when braking the vehicle, and charges the battery of the power supply device 100. 13, the vehicle HV may be provided with a charging plug 98 for charging the power supply device 100. The power supply device 100 can be charged by connecting this charging plug 98 to an external power source.

[0051] (Power supply unit for electric vehicles) FIG. 14 shows an example of a power supply device mounted on an electric vehicle that runs only on a motor. The vehicle EV equipped with the power supply device shown in this figure includes a vehicle body 91, a motor 93 for driving the vehicle body 91, wheels 97 driven by the motor 93, a power supply device 100 that supplies power to the motor 93, and a generator 94 that charges the battery of the power supply device 100. The power supply device 100 is connected to the motor 93 and the generator 94 via a DC / AC inverter 95. The motor 93 is driven by power supplied from the power supply device 100. The generator 94 is driven by energy generated when the vehicle EV is subjected to regenerative braking, and charges the battery of the power supply device 100. The vehicle EV also includes a charging plug 98, which can be connected to an external power source to charge the power supply device 100.

[0052] (Power supply device for power storage device) Furthermore, the present invention does not limit the use of the power supply device to a power supply for a motor that runs a vehicle. The power supply device according to the embodiment can also be used as a power supply for a power storage device that charges a battery with power generated by solar power generation, wind power generation, or the like and stores the power. Fig. 15 shows a power storage device that charges a battery of a power supply device 100 with a solar cell 82 and stores the power.

[0053] The power storage device shown in FIG. 15 charges a battery of a power supply device 100 with power generated by a solar cell 82 arranged on the roof or rooftop of a building 81 such as a house or a factory. This power storage device charges the battery of the power supply device 100 with a charging circuit 83 using the solar cell 82 as a charging power source, and then supplies power to a load 86 via a DC / AC inverter 85. For this reason, this power storage device has a charging mode and a discharging mode. The power storage device shown in the figure connects the DC / AC inverter 85 and the charging circuit 83 to the power supply device 100 via a discharge switch 87 and a charge switch 84, respectively. The discharge switch 87 and the charge switch 84 are switched ON / OFF by a power storage device power supply controller 88. In the charge mode, the power supply controller 88 switches the charge switch 84 ON and the discharge switch 87 OFF to allow charging from the charging circuit 83 to the power supply device 100. Furthermore, when charging is completed and the battery is fully charged, or when a predetermined charged capacity or more has been reached, the power supply controller 88 switches the charging switch 84 OFF and the discharging switch 87 ON to switch to a discharging mode, permitting discharging from the power supply device 100 to the load 86. Furthermore, if necessary, the charging switch 84 can be turned ON and the discharging switch 87 can be turned ON to supply power to the load 86 and charge the power supply device 100 at the same time.

[0054] Furthermore, although not shown, the power supply device can also be used as a power source for a power storage device that uses late-night power at night to charge and store electricity in a battery. A power supply device that is charged with late-night power is charged with late-night power, which is surplus electricity from power plants, and outputs electricity during the day when the power load is high, making it possible to limit daytime peak power to a low level. Furthermore, the power supply device can also be used as a power source that charges with both the output of solar cells and late-night power. This power supply device effectively uses both the power generated by solar cells and the late-night power, and can efficiently store electricity while taking into account the weather and power consumption.

[0055] The above-described power storage device can be suitably used for applications such as a backup power supply device that can be mounted on a computer server rack, a backup power supply device for wireless base stations for mobile phones and the like, a power supply for home or factory storage, a power supply for street lights, a power storage device combined with a solar cell, and a backup power supply for traffic lights and road traffic indicators. [Industrial Applicability]

[0056] The power supply device according to the present invention can be suitably used as a large current power supply for the power supply of motors for driving electric vehicles such as hybrid cars, fuel cell cars, electric cars, and electric motorcycles. Examples of such power supply devices include plug-in hybrid electric cars, hybrid electric cars, electric cars, and the like that can switch between EV driving mode and HEV driving mode. The power supply device can also be suitably used for applications such as a backup power supply device that can be mounted on a rack for a computer server, a backup power supply device for wireless base stations for mobile phones, and the like, a power storage power supply for home and factory use, a power supply for street lights, and the like, a power storage device combined with a solar cell, and a backup power supply for traffic lights, and the like. [Explanation of symbols]

[0057] 100...Power supply device 1. Battery cell 2…Separator 3…End plate 4. Binding bar 10…Battery block 11…Battery case 12...Sealing plate 13...Electrode terminal 14...Safety valve 15...Electrode 15A…U curve section 15a...electrode layer 15b...electrode layer 15c…Insulating sheet 20…Plate-shaped part 21, 21A, 21B...parallel convex strips 22...Parallel groove 23, 23A, 23B, 23C, 23D…Convex 24...Resection part 25…Concave and convex layer 25A…First uneven layer 25B: Second uneven layer 81…Building 82…Solar cell 83…Charging circuit 84…Charging switch 85…DC / AC inverter 86…Load 87…Discharge switch 88…Power supply controller 91…Vehicle body 93…Motor 94…Generator 95…DC / AC inverter 96…Engine 97...Wheel 98…Charging plug HV, EV...Vehicles

Claims

1. a battery block formed by stacking a plurality of battery cells in a thickness direction with separators sandwiched between the battery cells; a pair of end plates disposed on both end surfaces of the battery block; a bind bar that is connected to the pair of end plates and that fixes the battery block in a pressurized state via the end plates; A power supply device comprising: The separator is made of an elastomer and has a plate-shaped portion, A power supply device in which uneven layers with different shapes are formed on each surface of the plate-like portion, and the amount of change in thickness with respect to a pressing force is made different on each surface of the plate-like portion.

2. 2. The power supply device according to claim 1, The power supply device, wherein the separator elastomer is synthetic rubber.

3. 3. The power supply device according to claim 2, The elastomeric synthetic rubber is The power supply device is made of any of fluororubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprone rubber, nitrile rubber, hydrogenated nitrile rubber, polyisobutylene rubber, ethylene propylene rubber, ethylene vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, silicone rubber, thermoplastic olefin rubber, ethylene propylene diene rubber, butyl rubber, and polyether rubber.

4. 4. The power supply device according to claim 1, The separator is The power supply device has a plurality of protrusions on the surface of the plate-shaped portion, which constitute the uneven layer.

5. 5. The power supply device according to claim 4, A power supply device, wherein the convex portions having different shapes are provided on both sides of the plate-like portion.

6. 6. The power supply device according to claim 4 or 5, On both sides of the plate-shaped portion, A power supply device comprising the protrusions, the protrusions having different contact areas with the battery cells in an uncompressed state.

7. 7. A power supply device according to claim 4, The uneven layer is From the contact portion with the battery cell toward the plate-shaped portion, A power supply device having a convex portion whose cross-sectional area in a plane parallel to the surface of the plate-shaped portion becomes large.

8. 8. A power supply device according to claim 4, The convex portion is a long and narrow convex strip, A power supply device having a plurality of rows of the ridges provided on the surface of the plate-shaped portion.

9. 9. The power supply device according to claim 8, The plurality of rows of ridges are Parallel ridges arranged parallel to each other, The uneven layer is A power supply device having multiple rows of parallel ridges and multiple rows of parallel grooves arranged alternately.

10. 10. The power supply device according to claim 9, the uneven layer includes a first uneven layer formed on one surface of the plate-shaped portion and a second uneven layer formed on the other surface of the plate-shaped portion; the first uneven layer is provided with the parallel ridges having a rectangular cross-sectional shape, a power supply device, wherein the second uneven layer is provided with parallel ridges whose width gradually narrows toward a connection surface with the battery cell;

11. 11. The power supply device according to claim 10, A power supply device, wherein the second uneven layer is provided with the parallel ridges having a cross-sectional shape that is either arch-shaped, triangular, or trapezoidal.

12. An electric vehicle comprising the power supply device according to any one of claims 1 to 11, The power supply device; a driving motor supplied with power from the power supply device; and a vehicle body having the power supply device and the motor mounted thereon; a wheel driven by the motor to move the vehicle body; An electric vehicle equipped with

13. A power storage device comprising the power supply device according to any one of claims 1 to 11, The power supply device; a power supply controller for controlling charging and discharging of the power supply device; Equipped with The power supply controller enables charging of the battery cells with external power and controls the charging of the battery cells.

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