Power supply device, electric vehicle having the same, and power storage device

Abstract

A power supply device comprises a battery block (10) formed by stacking a plurality of battery cells (1) in a thickness direction with a separator (2) interposed therebetween, a pair of end plates (3) disposed at both end surfaces of the battery block (10), and a tightening strip (4) connected to the pair of end plates (3) and fixing the battery block (10) in a pressurized state by means of the end plates (3). The separator (2) is an elastic body, and both surfaces of a plate-shaped portion (20) of the separator (2) are formed with concave-convex layers (25) having different thickness variations relative to a pressing force.

Description

Technical Field

[0001] The present invention relates to a power supply device formed by stacking a plurality of battery cells, and an electric vehicle and a power storage device having the power supply device. Background Art

[0002] A power supply device formed by stacking a plurality of battery cells is suitable for supplying power to an electric motor mounted on an electric vehicle to drive the vehicle, a power supply that uses natural energy such as solar cells, a power supply that charges the battery late at night, and a backup power supply during a power outage. A power supply device of this structure has a partition sandwiched between the stacked battery cells. In a power supply device formed by stacking a plurality of battery cells with a partition between them, the stacked battery cells are fixed in a pressurized state in order to prevent positional displacement caused by expansion of the battery cells. In order to achieve the above purpose, in the power supply device, a pair of end plates are arranged on both end surfaces of a battery block formed by stacking a plurality of battery cells, and the pair of end plates are connected by a tightening strip (see patent document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-204708 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In the power supply device, a plurality of battery cells are stacked to form a battery block. A pair of end plates are arranged at both end faces of the battery block. The two end faces are kept in a pressurized state with a fairly strong pressure and connected by a tightening strip. In the power supply device, the battery cells are fixed in a strongly pressurized state to prevent relative movement of the battery cells and failures caused by vibration. For example, in the case of a stacking surface area of ​​about 100 cm 2 In a device with battery cells, the end plates are pressed with a strong force of several tons and fixed with a tightening strip. In a power supply device with this structure, a plate-shaped insulating plastic plate is used for the partition to insulate the adjacently stacked battery cells. When the plastic plate partition expands due to the increase in the internal pressure of the battery cell, it cannot absorb the expansion of the battery cell. In this state, the surface pressure between the battery cell and the partition increases sharply, which will act on the end plates and the tightening strip. Therefore, the end plates and the tightening strips are required to have extremely strong materials and shapes, which has the disadvantages of making the power supply device heavier and larger and increasing the material cost.

[0008] The present invention has been developed for the purpose of eliminating the above disadvantages, and one of the objects of the present invention is to provide a technology for absorbing the expansion of a battery cell by using a separator.

[0009] Solutions for solving problems

[0010] A power supply device according to one embodiment of the present invention comprises a battery block formed by stacking a plurality of battery cells in a thickness direction with a separator interposed therebetween, a pair of end plates disposed at both end surfaces of the battery block, and a tightening bar connected to the pair of end plates and fixing the battery block in a pressurized state via the end plates. The separator is an elastic body, and both surfaces of a plate-like portion of the separator are formed into concave-convex layers having different thickness variations with respect to a pressing force.

[0011] An electric vehicle according to one embodiment of the present invention comprises: the power supply device described above; a motor for traveling, to which electric power is supplied from the power supply device; a vehicle body equipped with the power supply device and the motor; and wheels driven by the motor to cause the vehicle body to travel.

[0012] A power storage device according to one embodiment of the present invention comprises: the power supply device described above; and a power supply controller that controls charging and discharging of the power supply device, wherein the power supply controller can charge a battery cell with power from outside, and the power supply controller controls charging of the battery cell.

[0013] Effects of the Invention

[0014] In the above power supply device, the parallel ridges of the separator partially press the electrode layers of the battery cells, thereby suppressing battery degradation caused by a decrease in the fluidity of the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view of a power supply device according to one embodiment of the present invention.

[0016] Figure 2 yes Figure 1 A vertical cross-sectional view of the power supply unit shown.

[0017] Figure 3 yes Figure 1 A horizontal cross-sectional view of the power supply unit shown.

[0018] Figure 4 It is a partially enlarged cross-sectional view showing the stacking structure of battery cells and separators.

[0019] Figure 5 This is a partially enlarged cross-sectional view showing another example of the partition.

[0020] Figure 6 It is a partially enlarged cross-sectional view showing another example of the partition.

[0021] Figure 7 It is an exploded perspective view showing the stacking structure of battery cells and separators.

[0022] Figure 8 yes Figure 7 A rear perspective view of a battery cell and separator is shown.

[0023] Fig. 9 This is an enlarged cross-sectional view of the main part showing a state in which the surface of the swollen battery cell is pressed by the parallel convex lines and deformed into a corrugated shape.

[0024] Fig.10 It is a perspective view showing another example of the partition plate.

[0025] Fig.11 yes Fig.10 Rear perspective view of the partition.

[0026] Fig.12 This is an exploded perspective view showing another example of the stacked structure of battery cells and separators.

[0027] Fig.13 This is a block diagram showing an example in which a power supply device is mounted on a hybrid vehicle that runs using an engine and an electric motor.

[0028] Fig.14 This is a block diagram showing an example in which a power supply device is mounted on an electric vehicle that runs only with an electric motor.

[0029] Fig.15 This is a block diagram showing an example of application to a power supply device for power storage. DETAILED DESCRIPTION

[0030] The present invention is described in detail below based on the accompanying drawings. In addition, in the following description, terms indicating specific directions and positions (such as "upper", "lower" and other terms including these terms) may be used as needed, but these terms are used to facilitate understanding of the invention with reference to the accompanying drawings, and the protection scope of the present invention is not limited by the meaning of these terms. In addition, the parts with the same reference numerals shown in multiple drawings represent the same or equivalent parts or components.

[0031] Furthermore, the embodiments shown below are embodiments of specific examples of the technical ideas of the present invention, and the present invention is not limited to the following embodiments. In addition, as long as there is no specific description, the size, material, shape, relative configuration, etc. of the components described below are not intended to limit the scope of the present invention to only these, but are intended to be illustrative. In addition, the content described in one embodiment or example can also be applied to other embodiments or examples. In addition, in order to clearly explain, there is a situation where the size, positional relationship, etc. of the components shown in the drawings are exaggerated.

[0032] A power supply device according to a first embodiment of the present invention comprises a battery block formed by stacking a plurality of battery cells in a thickness direction with a separator interposed therebetween, a pair of end plates disposed at both end surfaces of the battery block, and a tightening bar connected to the pair of end plates and fixing the battery block in a pressurized state via the end plates. The separator is an elastic body, and both surfaces of a plate-like portion of the separator are formed into concave-convex layers having different thickness variations with respect to a pressing force.

[0033] The partition of the above power supply device is provided on both sides with different thickness changes relative to the pressing force, that is, a concave-convex layer that changes softly when pressed by the battery cell and a concave-convex layer with less change. Therefore, in the area where the battery cell expands less, the soft concave-convex layer that is easy to deform absorbs the expansion. When the expansion of the battery cell increases and the soft concave-convex layer is flattened and cannot absorb the expansion, the concave-convex layer that is not easy to deform absorbs the expansion. When the expansion of the battery cell further increases and the concave-convex layer that is not easy to deform is also flattened and cannot absorb the expansion, the plate-shaped portion is deformed to be thinner to absorb the expansion of the battery cell. If the concave-convex layer is flattened and further pressurized, the plate-shaped portion of the partition is deformed to be thinner to absorb the expansion of the battery cell. The plate-shaped portion of the elastomer is not easy to deform compared to the concave-convex layer, and elastically deforms under a strong pressing force exceeding the elastic limit of the concave-convex layer to further absorb the expansion of the battery cell. Therefore, in the separator having concavoconvex layers with different thickness changes relative to the pressing force on both sides of the plate-shaped portion, the easily deformable concavoconvex layer absorbs the smaller expansion of the battery cell, the less deformable concavoconvex layer absorbs the larger expansion, and the larger expansion is absorbed by flattening the plate-shaped portion to be thinner. Therefore, the above separator uses the concavoconvex layer to absorb the smaller expansion of the battery cell that occurs more frequently, uses the plate-shaped portion to absorb the larger expansion, and uses the less deformable concavoconvex layer to absorb the intermediate expansion between the smaller expansion and the larger expansion of the battery cell, so it has the advantage of being able to absorb the smaller expansion to the larger expansion of the battery cell in an ideal state. In addition, by using the easily deformable concavoconvex layer, it is also possible to expect the effect of being able to absorb the dimensional tolerance of the battery cell and the separator.

[0034] Furthermore, in the above power supply device, concave-convex layers with different deformation amounts are provided on both sides of the plate-like portion of the elastic body. The three elastic deformation layers with different deformation amounts relative to the pressing force suppress the increase in surface pressure caused by the expansion of the battery cell, thereby being able to efficiently absorb the expansion of the battery cell and alleviate the stress acting on the end plate and the tightening strip. The concave-convex layer can efficiently absorb the initial expansion of the battery cell, but if the expansion of the battery cell increases and exceeds the elastic limit, the concave-convex layer cannot be elastically deformed, resulting in a sharp increase in the stress of the end plate and the tightening strip. However, in the area exceeding the elastic limit of the concave-convex layer, the plate-like portion of the elastic body will undergo elastic deformation to suppress the increase in stress of the end plate and the tightening strip. Therefore, the expansion of the battery cell can be effectively absorbed and the maximum stress acting on the end plate and the tightening strip can be suppressed. In a power supply device that can suppress the maximum stress acting on the end plate and the tightening strip, the end plate and the tightening strip can be made thinner and lighter.

[0035] In addition, in a power supply device in which the three-layer elastic deformation layer composed of the concave-convex layer on both sides and the plate-shaped portion effectively absorbs the expansion of the battery cell, the relative position shift of the battery cell caused by the expansion of the battery cell can be prevented. This can also prevent the disadvantages of the electrical connection part of the battery cell. This is because, in the stacked battery cells, the bus bar of the metal plate is fixed to the electrode terminal for electrical connection, but if the battery cell is relatively shifted, unreasonable stress will be applied to the bus bar and the electrode terminal, resulting in failure.

[0036] In the power supply device according to the second embodiment of the present invention, the elastic body of the spacer is synthetic rubber.

[0037] In the power supply device of the third embodiment of the present invention, the synthetic rubber of the elastomer is any one of fluororubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, nitrile rubber, hydrogenated nitrile rubber, polyisobutylene rubber, ethylene-propylene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, polyurethane rubber, silicone rubber, thermoplastic olefin rubber, ethylene propylene diene rubber, butyl rubber, and polyether rubber.

[0038] In the power supply device according to the fourth embodiment of the present invention, the separator has a plurality of convex portions provided on the surface of the plate-like portion to form a concavo-convex layer.

[0039] In the power supply device according to the fifth embodiment of the present invention, convex portions having different shapes are provided on both surfaces of the plate-like portion, thereby forming a concavo-convex layer having different thickness variations with respect to the pressing force of the battery cell.

[0040] In the power supply device according to the sixth embodiment of the present invention, convex portions having different contact areas with the battery cells in the non-compressed state are provided on both surfaces of the plate-like portion.

[0041] In the power supply device according to the seventh embodiment of the present invention, the concavo-convex layer has convex portions whose cross-sectional areas in a plane parallel to the surface of the plate-shaped portion increase as they go from the contact portion with the battery cell toward the plate-shaped portion.

[0042] In the power supply device according to the eighth embodiment of the present invention, the protrusions are elongated convex stripes, and a plurality of rows of convex stripes are provided on the surface of the plate-like portion.

[0043] In the power supply device according to the ninth embodiment of the present invention, the plurality of rows of ridges are parallel ridges arranged parallel to each other, and the plurality of rows of parallel ridges and the plurality of rows of parallel grooves are alternately arranged in the concavo-convex layer.

[0044] In the above power supply device, the parallel ridges of the separator partially press the electrode layer of the battery cell to improve the fluidity of the electrolyte. The reason why the comb-shaped separator with parallel ridges and parallel grooves alternately provided on the opposite surface opposite to the battery cell can improve the fluidity of the electrolyte is that the electrode becomes high density in the area pressed by the parallel ridges, but the electrode becomes low density in the opposite area opposite to the parallel grooves that is not pressed by the parallel ridges, so that the electrolyte is easy to move.

[0045] In the power supply device of the tenth embodiment of the present invention, parallel convex strips having a square cross-sectional shape are provided on the first concave-convex layer of the plate-like portion, and parallel convex strips having a lateral width that gradually narrows toward the battery cell connection surface are provided on the second concave-convex layer of the plate-like portion, thereby providing concave-convex layers having different thickness changes relative to the pressing force on both sides of the plate-like portion.

[0046] In addition, in this specification, the cross section of the parallel ridges means the cross section in the cut surface perpendicular to the longitudinal direction of the parallel ridges.

[0047] In the power supply device according to the eleventh embodiment of the present invention, the second concavo-convex layer of the plate-shaped portion is provided with parallel convex stripes having a cross-sectional shape of any one of a triangular shape, an arch shape, and a trapezoidal shape.

[0048] (Implementation Method 1)

[0049] Figure 1 Stereoscopic image, Figure 2 A vertical cross-sectional view of Figure 3 The power supply device 100 shown in the horizontal cross-sectional view includes a battery block 10 formed by stacking a plurality of battery cells 1 in the thickness direction via a partition 2, a pair of end plates 3 arranged at both end surfaces of the battery block 10, and a tightening bar 4 connecting the pair of end plates 3 and fixing the battery block 10 in a pressurized state by means of the end plates 3.

[0050] (Battery block 10)

[0051] The battery block 10 is formed by stacking a plurality of battery cells 1 in a thickness direction with separators 2 interposed therebetween. The plurality of battery cells 1 are rectangular battery cells having a quadrilateral outer shape. The plurality of battery cells 1 are stacked so that their upper surfaces are in the same plane to form the battery block 10 .

[0052] (Battery cell 1)

[0053] For battery cell 1, Figure 4 As shown, the electrode 15 is inserted into the bottom-sealed battery case 11, and the sealing plate 12 is laser welded to the upper opening of the battery case 11 and fixed airtightly, so that the interior is set as a sealed structure. In addition, the interior of the battery case 11 is filled with an electrolyte (not shown). Figure 1 As shown, a pair of positive and negative electrode terminals 13 are provided at both ends of the upper surface of the sealing plate 12 so as to protrude upward. A safety valve 14 is provided between the electrode terminals 13. The safety valve 14 opens to release the internal gas when the internal pressure of the battery cell 1 rises to a predetermined value or more. The safety valve 14 can prevent the internal pressure of the battery cell 1 from rising.

[0054] The battery cell 1 is a lithium ion secondary battery. In the power supply device 100 in which the battery cell 1 is a lithium ion secondary battery, there is an advantage that the charging capacity can be large 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.

[0055] (End plate 3, tightening strip 4)

[0056] The end plate 3 is a metal plate that is pressed by the battery block 10 without being deformed and has an outer shape roughly equal to that of the battery cell 1, and is connected to the two side edges thereof with tie bars 4. The tie bars 4 connect the battery cells 1 stacked with the end plate 3 in a pressurized state and fix the battery block 10 in a pressurized state with a predetermined pressure.

[0057] (Partition 2)

[0058] The separator 2 is sandwiched between the stacked battery cells 1, absorbs the expansion of the battery cells 1 caused by the increase in internal pressure, and insulates the adjacent battery cells 1. In the battery block 10, bus bars (not shown) are fixed to the electrode terminals 13 of adjacent battery cells 1, so that the battery cells 1 are connected in series or in parallel. In the battery cells 1 connected in series, since a potential difference is generated in the battery case, the separator 2 can be used to insulate the stacking. In the battery cells 1 connected in parallel, although no potential difference is generated in the battery case 11, in order to prevent thermal runaway, the separator 2 can be used to insulate the stacking.

[0059] The partition 2 elastically deformed by being pressed by the battery cell 1 is made of an elastomer. The elastomer of the partition 2 is a rubber-like elastomer with a hardness of, for example, A30 to A90 degrees, so that it is elastically deformed by being pressed by the battery cell 1. The elastomer of the partition 2 is preferably a synthetic rubber. For the synthetic rubber, any one of fluororubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, nitrile rubber, hydrogenated nitrile rubber, polyisobutylene rubber, ethylene-propylene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, polyurethane rubber, silicone rubber, thermoplastic olefin rubber, ethylene-propylene-diene rubber, butyl rubber, and polyether rubber can be used alone or as a component formed by stacking a plurality of synthetic rubber sheets. In particular, since ethylene-propylene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, fluororubber, and silicone rubber have excellent thermal insulation properties, a high level of safety can be achieved until the temperature of the battery cell 1 rises to a high temperature. In addition, for the separator 2 whose elastic body is made of polyurethane rubber, it is particularly preferable to use thermoplastic polyurethane rubber or foamed polyurethane rubber.

[0060] The separator 2 can easily absorb the expansion of the battery cell 1 and relieve the maximum stress of the end plate 3 and the tightening strip 4. The ideal separator 2 that absorbs the expansion of the battery cell 1 can effectively absorb the smaller expansion of the battery cell 1 and also absorb the larger expansion to suppress the maximum stress of the end plate 3 and the tightening strip 4. For the separator 2 to achieve this characteristic, it is required to have the following characteristics: the characteristic of being able to quickly elastically deform and easily absorb the expansion in the area where the expansion of the battery cell 1 is relatively small during the process of the internal pressure of the battery cell 1 rising and the pressing force gradually increasing, and the characteristic of being able to deform without exceeding the elastic limit and absorb the expansion even when the expansion of the battery cell 1 reaches the maximum area.

[0061] Since the elastomer undergoes elastic deformation, it can be set as a plate-shaped partition 2 to absorb the expansion of the battery cell 1. The partition 2 is made of an elastomer with a small Young's modulus, and can easily absorb the small expansion of the battery cell 1. However, if the expansion of the battery cell 1 becomes the maximum area and the pressing force increases, the partition 2 will exceed the elastic limit and cannot easily absorb the expansion. If the partition 2 is made of an elastomer with a large Young's modulus in order to increase the pressure of the elastic limit of the partition 2, the small expansion of the battery cell 1 cannot be easily and smoothly absorbed. The expansion of the battery cell 1 is determined by external conditions such as the charge and discharge current. Smaller expansion and larger expansion will repeat randomly. The frequency of smaller expansion is higher than that of larger expansion. The characteristic of being able to easily and smoothly absorb smaller expansion is extremely important. For the partition 2 of the elastic body with a small Young's modulus that can easily absorb smaller expansion with a higher frequency, since its elastic limit is limited to a low value, it is impossible to stably absorb the larger expansion of the maximum area. If the separator 2 cannot absorb the larger expansion of the largest area of ​​the battery cell 1, the pressure of the battery cell 1 on the separator 2 will increase, resulting in a significant increase in the internal stress of the end plate 3 and the tightening strip 4.

[0062] exist Figures 4 to 6 In the separator 2 shown, in order to smoothly absorb the smaller expansion of the battery cell 1 and increase the elastic limit to also absorb the larger expansion of the battery cell 1, a plurality of protrusions 23 are provided on the surface of the plate-shaped portion 20 to form a concavo-convex layer 25. The separator 2 shown in these figures is provided with protrusions 23 of different shapes on both sides, thereby forming a concavo-convex layer 25 with different thickness changes relative to the pressing force of the battery cell 1. For the concavo-convex layer 25 provided on both sides of the plate-shaped portion 20, as shown in the figure, there are protrusions 23 with different contact areas with the battery cell 1 in the non-compressed state, thereby forming a concavo-convex layer 25 with different thickness changes relative to the pressing force.

[0063] In these figures, the separator 2 is configured as follows: one surface (the left surface in the figure) of the plate-like portion 20 is configured as the first concavoconvex layer 25A, and the other surface (the right surface in the figure) of the plate-like portion 20 is configured as the second concavoconvex layer 25B, so that the displacement amount of the second concavoconvex layer 25B relative to the pressing force is greater than the displacement amount of the first concavoconvex layer 25A relative to the pressing force, that is, it can easily absorb the small expansion of the battery cell 1. The separator 2 shown in these figures is configured as follows: the cross-sectional shape of the convex portion 23A provided in the first concavoconvex layer 25A is configured as a square shape, and the cross-sectional area of ​​the convex portions 23B, 23C, and 23D provided in the second concavoconvex layer 25B in the plane parallel to the surface of the plate-like portion increases as it moves from the contact portion with the battery cell 1 toward the plate-like portion 20. Figure 4 The cross-sectional shape of the convex portion 23B of the second concavo-convex layer 25B of the partition plate 2 is set to be semicircular or arched, Figure 5The cross-sectional shape of the convex portion 23C of the second concavo-convex layer 25B of the separator 2 is set to a triangular shape, Figure 6 The cross-sectional shape of the convex portion 23D of the second concavo-convex layer 25B of the separator 2 is set to a trapezoidal shape, so that each is set to a shape that is easier to deform than the quadrilateral convex portion 23A of the first concavo-convex layer 25A which is a square shape.

[0064] for Figure 7 and Figure 8 In the separator 2 shown in the stereoscopic view, the convex portion 23 of the concave-convex layer 25 is configured as an elongated convex strip and a plurality of rows of convex strips are provided on the surface of the plate-like portion 20. Furthermore, for the separator 2 in the figure, the plurality of rows of convex strips provided on the concave-convex layer 25 are parallel convex strips 21 arranged parallel to each other, parallel grooves 22 are provided between the plurality of rows of parallel convex strips 21, and the parallel convex strips 21 and the parallel grooves 22 are alternately arranged. The plurality of rows of parallel convex strips 21 of the separator 2 locally press the surface of the expanded battery cell, and the parallel convex strips 21 undergo elastic deformation to absorb the expansion of the battery cell 1. For the separator 2, the parallel convex strips 21 provided on the first concave-convex layer 25A and the second concave-convex layer 25B are configured as Figures 4 to 6 By adopting the cross-sectional shape shown in FIG. 2 , the first concavo-convex layer 25A and the second concavo-convex layer 25B can optimize the amount of deformation of the separator 2 with respect to the pressing force of the battery cell 1 .

[0065] For the separator 2, in the region where the expansion of the battery cell 1 is small, the parallel ridges 21B of the second concave-convex layer 25B are elastically deformed to absorb the expansion of the battery cell 1 while the parallel ridges 21A of the first concave-convex layer 25A are basically not deformed, and when the expansion of the battery cell 1 increases and the parallel ridges 21B of the second concave-convex layer 25B become basically flattened, the parallel ridges 21A of the first concave-convex layer 25A are elastically deformed to absorb the expansion of the battery cell 1. Furthermore, when the expansion of the battery cell 1 increases and the parallel ridges 21A of the first concave-convex layer 25A become basically flattened, the plate-shaped portion 20 is elastically deformed to absorb the expansion of the battery cell 1.

[0066] The battery cell 1 pressed by the parallel ridges 21 has its region pressed by the parallel ridges 21 become a recessed portion, and its region facing the parallel grooves 22 protrudes and deforms into a corrugated shape. Fig. 9The enlarged cross-sectional view of the main part of the battery cell 1 exaggerates the state in which the surface of the battery cell 1 is pressed by the parallel ridges 21 and deformed into a waveform. For the battery cell 1 whose surface is deformed into a waveform, the surface of the electrode 15 of the stacked structure housed inside the battery case 11 is deformed into a waveform. Since the area A of the electrode 15 of the stacked structure that is pressed by multiple rows of parallel ridges 21 to form a recessed portion becomes high-density and the relative area opposite to the parallel grooves 22, that is, the protruding area B becomes low-density, the low-density area B is generated in a stripe shape, and the low-density area B can improve the fluidity of the electrolyte. In addition, the above separator 2 utilizes the elastic deformation of the elastomer to absorb the expansion of the battery cell 1, and causes the electrode 15 to generate the low-density area B in a stripe shape, so it has the following characteristics: even when the battery cell 1 expands and the fluidity of the electrolyte is reduced, the electrode 15 can generate the low-density area B in a stripe shape to improve the fluidity of the electrolyte.

[0067] Figure 7 and Figure 8 The battery cell 1 shown is a square battery in which the stacking surface of the stacking separator 2 of the battery case 11 is set to a quadrilateral shape, and the elongated strip-shaped positive and negative electrode layers 15a and 15b are wound to form a spiral electrode 15, and the spiral electrode 15 is made into a plate shape pressed into a flat shape and accommodated in the battery case 11. The electrode 15 is made of elongated strip-shaped positive and negative electrode layers 15a and 15b stacked with an insulating sheet 15c interposed therebetween, and the spiral electrode 15 is formed, and the spiral electrode 15 is pressed into a flat shape and accommodated in the square battery case 11. As shown in the figure, the elastic separator 2 is arranged in a posture in which the parallel ridges 21 and the parallel grooves 22 extend in the width direction of the strip-shaped positive and negative electrode layers 15a and 15b. The parallel ridges 21 of the partition 2 are arranged parallel to the extension direction of the U-shaped bend 15A of the spiral electrode 15, and the high-density region A and the low-density region B extending along the width direction of the electrode layers 15a and 15b on the surface of the electrode 15 are formed into stripes. Therefore, the high-density region A and the low-density region B can be easily arranged in stripes on the spiral electrode 15 to improve the fluidity of the electrolyte.

[0068] Taking into account the hardness of the elastomer, the lateral 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 enable the parallel ridges 21 to press the surface of the battery case 11 and deform it into a waveform. For example, for a partition 2 whose hardness of the elastomer is set to A30 to A90 degrees, for example, the lateral width (W1) of the bottom of the parallel ridges 21, that is, the boundary area with the plate-like portion 20, is set to be greater than 1 mm and less than 20 mm, preferably greater than 2 mm and less than 10 mm, so that the metal battery case 11 of the expanded battery cell 1 can be pressed and deformed into a waveform. Figure 7 and Figure 8 In the separator 2, the lateral width (W1) of the parallel ridges 21B of the second concavo-convex layer 25B that is easily deformed is narrower than the lateral width (W1) of the parallel ridges 21A of the first concavo-convex layer 25A that is not easily deformed. The height (h) of the parallel ridges 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 grooves 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 lateral width (W1) of the parallel ridges 21 to the opening width (W2) of the parallel grooves 22 is 0.1 or more and 10 or less, preferably 0.5 or more and 2 or less.

[0069] By increasing the height (h) of the parallel ridges 21 and expanding the opening width (W2) of the parallel grooves 22, the elastic separator 2 can absorb the expansion of the battery case 11 to a greater extent. However, if the parallel ridges 21 are too high, the separator will become thicker and more likely to be buckled. Therefore, considering the thickness allowed by the separator 2 and the fact that the battery case 11 can be partially pressed to deform into a waveform, the height (h) of the parallel ridges 21 is set to the above range. In addition, the opening width (W2) of the parallel grooves 22 and the ratio (W1 / W2) of the lateral width (W1) of the parallel ridges 21 to the opening width (W2) of the parallel grooves 22 determine the pitch at which the surface of the battery case 11 is deformed into a waveform. Therefore, considering the fact that multiple rows of parallel ridges 21 are used to support the expansion of the battery cell 1 and to make the fluidity of the electrolyte in a preferred state, they are set to the above range. 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 stacking surface is 100 cm 2 For a power supply device 100 in which the lateral width (W1) of the parallel ridges 21 and the opening width (W2) of the parallel grooves 22 are 5 mm, the height (h) of the parallel ridges 21 is 0.5 mm, the hardness of the elastomer is A60 degrees, and the number of stacked battery cells 1 is 12, the surface of the battery cell 1 opposite to the partition 2 is deformed into a waveform in the expanded state, which can improve the fluidity of the electrolyte.

[0070] In order to miniaturize the battery block 10 and increase the charging capacity, it is important for the power supply device 100 to make the separator 2 thinner and absorb the expansion of the battery cell 1. Therefore, the thickness (d) of the elastic separator 2 is, for example, 2 mm to 8 mm, more preferably 1.5 mm to 5 mm.

[0071] Figure 7 and Figure 8The separator 2 shown is structured as follows: the total length of the multiple parallel ridges 21 extending in the lateral width direction (horizontal direction in the figure) of the battery cell 1 is substantially equal to the lateral width of the battery cell 1, and the multiple parallel ridges 21 extending in strips parallel to each other are used to press the opposite surface of the battery cell 1. Fig.10 and Fig.11 As shown, the parallel ridges 21 extending in the longitudinal direction may be divided into a plurality of ridges. Fig.10 and Fig.11 The separator 2 shown in the figure is provided with a cutout 24 in the middle of the parallel ridges 21 to divide a row of parallel ridges 21 into a plurality of convex portions 23. Moreover, between adjacent parallel ridges 21, the arrangement of each convex portion 23 in the front view is staggered. That is, the positions of the convex portions 23 between adjacent parallel ridges 21 are staggered in the left-right direction in such a manner that the convex portion 23 of one parallel ridge 21 is located at a position opposite to the cutout 24 provided in another parallel ridge 21. In the separator 2 shown in the figure, in order to make the convex portions 23 of the parallel ridges 21 adjacent to each other staggered, cutout portions 24 are also provided at both ends of the parallel ridges 21 in every other row. In this way, the structure in which the plurality of divided convex portions 23 are arranged in a staggered shape has the advantage of being able to evenly disperse the pressing force received from the battery cell 1. Among them, the convex portions divided into a plurality of convex portions can be arranged vertically and horizontally, or can be arranged randomly. The separator 2 having the parallel ridges 21 of the above shape is more easily elastically deformed than the separator 2 having a structure in which the parallel ridges 21 are not divided, and has an advantage of being able to effectively absorb the expansion of the battery cell 1 .

[0072] And, for Fig.10 and Fig.11 The partition 2 of the shape shown can adjust the ease of elastic deformation of the parallel ridges 21 by adjusting the length (L1) of the protrusion 23 and the length (L2) of the cutout 24. For example, by increasing the ratio (L2 / L1) of the length (L2) of the cutout 24 to the length (L1) of the protrusion 23, the partition 2 can be made to be easily elastically deformed, and conversely, by reducing the ratio (L2 / L1), the partition 2 can be made to be less likely to be elastically deformed. That is, for the partition 2, by dividing the parallel ridges 21 into a plurality of pieces, the partition 2 can be easily deformed compared to a structure in which the parallel ridges 21 are not divided, and by adjusting the ratio (L2 / L1), the ease of deformation can be further adjusted. For example, for the partition 2, as Fig.10 and Fig.11As shown, by making the ratio (L2 / L1) of the second concavo-convex layer 25B smaller than the ratio (L2 / L1) of the first concavo-convex layer 25A, the second concavo-convex layer 25B is easier to deform, and the second concavo-convex layer 25B can be reliably deformed by a small expansion of the battery cell 1, and the first concavo-convex layer 25A suppresses deformation, so that it can be reliably deformed by an intermediate expansion of the battery cell 1. In addition, in the concavo-convex layer 25 on one surface, that is, one side, the ratio (L2 / L1) of the length (L2) of the cutout portion 24 to the length (L1) of the convex portion 23 can be changed according to the region. For example, in the region opposite to the central portion where the deformation amount is large when the battery cell 1 expands, the ratio (L2 / L1) can be increased to easily absorb the deformation, and in the region opposite to the peripheral portion where the deformation amount is small when the battery cell 1 expands, the ratio (L2 / L1) can be reduced to suppress the deformation.

[0073] In the above battery cell 1, if Figure 7 and Figure 8 As shown, the plate-shaped spiral electrode 15 is housed in the battery case 11 in such a manner that the axial direction is the width direction of the battery cell 1. Therefore, the separator 2 is stacked on the opposite surface of the battery cell 1 in such a manner that the extending direction of the parallel ridges 21 and the parallel grooves 22 is the width direction of the battery cell 1. In this way, by stacking the parallel ridges 21 and the parallel grooves 22 of the separator 2 in such a manner that they extend in the horizontal direction in the figure, the parallel ridges 21 and the parallel grooves 22 can be arranged on the surface of the battery cell 1 in a manner parallel to the axial direction of the spiral electrode 15. As a result, when the battery cell 1 expands, high-density areas and low-density areas extending in the width direction of the electrode layers 15a and 15b are formed in stripes on the surface of the spiral electrode 15, which can improve the fluidity of the electrolyte.

[0074] However, for battery cell 1, if Fig.12 As shown, the plate-shaped spiral electrode 15 can also be housed in the battery case 1 in such a manner that the axial direction is the height direction of the battery cell 1 and the depth direction of the battery case 11. The separator 2 stacked on the battery cell 1 of this structure is stacked on the opposite surface of the battery cell 1 in such a manner that the extending direction of the parallel ridges 21 and the parallel grooves 22 is the height direction of the battery cell 1. According to this structure, the parallel ridges 21 and the parallel grooves 22 of the separator 2 are stacked on the battery cell 1 in such a manner that they extend in the up-down direction in the figure, so that the parallel ridges 21 and the parallel grooves 22 can be arranged on the surface of the battery cell 1 in a manner parallel to the axial direction of the spiral electrode 15. As a result, when the battery cell 1 expands, high-density areas and low-density areas extending in the width direction of the electrode layers 15a and 15b are formed in stripes on the surface of the spiral electrode 15, thereby improving the fluidity of the electrolyte.

[0075] The above power supply device can be used as a power supply for a vehicle that supplies power to an electric motor that drives an electric vehicle. As an electric vehicle equipped with the power supply device, a hybrid vehicle that uses both an engine and an electric motor to drive, a plug-in hybrid vehicle, or an electric vehicle that uses only an electric motor to drive can be used, and the above power supply device can be used as a power supply for the above vehicles. In addition, an example of constructing a power supply device 100 is described. The power supply device 100 is a large-capacity, high-output power supply device obtained by connecting a plurality of the above power supply devices in series and in parallel in order to obtain power to drive a vehicle and also adding a necessary control circuit.

[0076] (Power supply device for hybrid vehicles)

[0077] Fig.13 An example of a hybrid vehicle equipped with a power supply device that runs using both an engine and an electric motor is shown. The vehicle HV equipped with the power supply device shown in the figure has a vehicle body 91, an engine 96 that drives the vehicle body 91 and an electric motor 93 for running, wheels 97 driven by the engine 96 and the electric motor 93 for running, a power supply device 100 that supplies power to the electric 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 electric motor 93 and the generator 94 via a DC / AC inverter 95. While charging and discharging the battery of the power supply device 100, the vehicle HV runs using both the electric motor 93 and the engine 96. The electric motor 93 is driven to run the vehicle in an area where the engine efficiency is poor, such as during acceleration and low-speed running. Electric power is supplied from the power supply device 100 to the electric motor 93 to drive the electric motor 93. The generator 94 is driven by the engine 96, or by regenerative braking when braking the vehicle, thereby charging the battery of the power supply device 100. In addition, as Fig.13 As shown, the vehicle HV may include a charging plug 98 for charging the power supply device 100. The power supply device 100 can be charged by connecting the charging plug 98 to an external power supply.

[0078] (Power supply device for electric vehicles)

[0079] in addition, Fig.14An example of an electric vehicle that runs only with an electric motor and is equipped with a power supply device is shown. The vehicle EV equipped with a power supply device shown in the figure has a vehicle body 91, a motor 93 for running 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 by means of a DC / AC inverter 95. The motor 93 is driven by the power supply device 100 by supplying power to the motor 93. The generator 94 is driven by the energy when the vehicle EV is regeneratively braked, and charges the battery of the power supply device 100. In addition, the vehicle EV has a charging plug 98, and the charging plug 98 can be connected to an external power source to charge the power supply device 100.

[0080] (Power supply device for power storage device)

[0081] The present invention does not limit the use of the power supply device to the power supply of the motor for driving the vehicle. The power supply device of the embodiment can also be used as a power supply of a power storage device that charges and stores electricity in a battery using electricity generated by solar power generation, wind power generation, etc. Fig.15 The electric power storage device that charges and stores electric power in the battery of the power supply device 100 using the solar cell 82 is shown.

[0082] Fig.15 The power storage device shown in the figure charges the battery of the power supply device 100 with the power generated by the solar cell 82 arranged on the roof, roof terrace, etc. of a building 81 such as a house or a factory. In the power storage device, after the battery of the power supply device 100 is charged by the charging circuit 83 using the solar cell 82 as a charging power source, the power is supplied to the load 86 via the DC / AC inverter 85. Therefore, the power storage device has a charging mode and a discharging mode. In the power storage device shown in the figure, the DC / AC inverter 85 and the charging circuit 83 are connected to the power supply device 100 via the discharging switch 87 and the charging switch 84, respectively. The on / off of the discharging switch 87 and the charging switch 84 are switched by the power supply controller 88 of the power storage device. In the charging mode, the power supply controller 88 switches the charging switch 84 to on and switches the discharging switch 87 to off, allowing the charging circuit 83 to charge the power supply device 100. In addition, when charging is completed and the battery is fully charged, or when the battery has been charged to a capacity greater than a predetermined value, the power controller 88 switches the charging switch 84 to the discharge mode by turning on the discharge switch 87, thereby allowing the power supply device 100 to discharge to the load 86. In addition, as required, the charging switch 84 can be turned on and the discharge switch 87 can be turned on to supply power to the load 86 and charge the power supply device 100 at the same time.

[0083] Furthermore, although not shown, the power supply device can also be used as a power supply for a power storage device that uses late-night electricity to charge and store electricity in a battery. The power supply device charged by late-night electricity can use the surplus electricity of the power station, that is, the late-night electricity, to charge, and output electricity during the day when the power load is large, limiting the peak power during the day to a small amount. Furthermore, the power supply device can also be used as a power supply that uses both the output of a solar cell and late-night electricity for charging. The power supply device can effectively use both the electricity generated by the solar cell and the late-night electricity, and can store electricity efficiently while taking into account the weather and power consumption.

[0084] The power storage device as described above can be preferably used for backup power supply devices that can be mounted on the rack of a computer server, backup power supply devices for wireless base stations such as mobile phones, power supply for power storage for home use or factory use, power supply for street lights, etc., power storage devices combined with solar cells, backup power supplies for signal equipment, traffic displays for roads, etc.

[0085] Industrial Applicability

[0086] The power supply device of the present invention can be appropriately used as a power supply for large currents used in the power supply of electric motors driving electric vehicles such as hybrid vehicles, fuel cell vehicles, electric vehicles, and electric motorcycles. For example, power supply devices for plug-in hybrid electric vehicles, hybrid electric vehicles, electric vehicles, etc. that can switch between EV driving mode and HEV driving mode can be cited. In addition, it can also be appropriately used for backup power supply devices that can be mounted on the racks of computer servers, backup power supply devices for wireless base stations such as mobile phones, power supply for household and factory use, power supply for street lights, etc., power storage devices combined with solar cells, backup power supplies for signal equipment, etc.

[0087] Description of Reference Numerals

[0088] 100. Power supply device; 1. Battery cell; 2. Partition plate; 3. End plate; 4. Tightening strip; 10. Battery block; 11. Battery case; 12. Sealing plate; 13. Electrode terminal; 14. Safety valve; 15. Electrode; 15A. U-shaped bending portion; 15a. Electrode layer; 15b. Electrode layer; 15c. Insulating sheet; 20. Plate-shaped portion; 21. 21A. 21B. Parallel convex strips; 22. Parallel grooves; 23. 23A. 23B. 23C. 23D. Convex portion; 24 , cut-away portion; 25, concave-convex layer; 25A, first concave-convex layer; 25B, second concave-convex layer; 81, building; 82, solar cell; 83, charging circuit; 84, charging switch; 85, DC / AC inverter; 86, load; 87, discharge switch; 88, power controller; 91, vehicle body; 93, motor; 94, generator; 95, DC / AC inverter; 96, engine; 97, wheel; 98, charging plug; HV, EV, vehicle.

Claims

1. A power supply device comprising a battery block formed by stacking a plurality of battery cells in a thickness direction with a partition interposed therebetween, a pair of end plates disposed at both end surfaces of the battery block, and a tightening bar connected to the pair of end plates and fixing the battery block in a pressurized state by means of the end plates, characterized in that: The separator is an elastic body, and both surfaces of the plate-shaped portion of the separator are formed into concave-convex layers with different thickness changes relative to the pressing force. The battery cell is a square battery cell with a quadrilateral shape. The elastic body of the partition is synthetic rubber. The separator is provided with a plurality of convex portions on the surface of the plate-like portion to form a concavo-convex layer. Convex portions of different shapes are provided on both sides of the plate-like portion. The convex part is a thin and long convex strip, and a plurality of rows of the convex strips are arranged on the surface of the plate-like part. The plurality of rows of convex strips are parallel convex strips arranged in parallel with each other, and the concave-convex layer is formed by alternately arranging a plurality of rows of parallel convex strips and a plurality of rows of parallel grooves. The parallel convex strips having a square cross-sectional shape are provided on the first concavo-convex layer of the plate-shaped portion. The second concave-convex layer of the plate-shaped portion is provided with the parallel convex strips whose lateral width gradually narrows toward the battery cell connection surface. Thus, the two surfaces of the plate-like portion are provided with concavo-convex layers having different thickness variations with respect to the pressing force. The second concavo-convex layer is more easily deformed than the first concavo-convex layer, and the first concavo-convex layer is more easily deformed than the plate-shaped portion.

2. The power supply device according to claim 1, characterized in that: The synthetic rubber of the elastomer is any one of fluororubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, nitrile rubber, hydrogenated nitrile rubber, polyisobutylene rubber, ethylene-propylene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, polyurethane rubber, silicone rubber, thermoplastic olefin rubber, ethylene-propylene-diene rubber, butyl rubber, and polyether rubber.

3. The power supply device according to claim 1, characterized in that: The convex portions having different contact areas with the battery cells in a non-compressed state are provided on both surfaces of the plate-shaped portion.

4. The power supply device according to claim 1, characterized in that: The concavo-convex layer includes the convex portion whose cross-sectional area in a plane parallel to the surface of the plate-shaped portion increases as it moves from a contact portion with the battery cell toward the plate-shaped portion.

5. The power supply device according to claim 1, characterized in that: The parallel convex stripes having a cross-sectional shape of any one of an arch shape, a triangle shape, and a trapezoidal shape are provided on the second concavo-convex layer of the plate-shaped portion.

6. An electric vehicle comprising the power supply device according to any one of claims 1 to 5, characterized in that: The electric vehicle has: the power supply device; a motor for driving, to which electric power is supplied from the power supply device; a vehicle body on which the power supply device and the electric motor are mounted; and The wheels are driven by the electric motor to cause the vehicle body to travel.

7. A power storage device comprising the power supply device according to any one of claims 1 to 5, characterized in that: The power storage device comprises: the power supply device; as well as a power supply controller that controls charging and discharging of the power supply device, The power controller can charge the battery cell with external power, and the power controller controls the battery cell to be charged.

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