power storage device

Abstract

A power storage device (1) is equipped with a plurality of power storage modules (100), a case (200), a cooler (300) provided below the case, and a heat conductor (400). The cooler (300) has a cooling flow path (302). The power storage module (100) has an upstream-side cell stack (101), a downstream-side cell stack (102), and an intermediate plate (103). The case (200) has a bottom wall (210) having a raised portion (212) raised toward the intermediate plate (103). The heat conductor (400) has an upstream-side heat conduction portion (410) disposed on the upstream side of the raised portion (212) and a downstream-side heat conduction portion (420) disposed on the downstream side of the raised portion (212). The downstream-side heat conduction portion (420) has a thickness smaller than that of the upstream-side heat conduction portion (410).

Description

Technical Field

[0001] This invention relates to energy storage devices. Background Technology

[0002] For example, Japanese Patent Application Publication No. 2020-53148 discloses a battery cell equipped with: a battery module comprising a plurality of battery cells arranged side-by-side along one direction; a cooler disposed below the battery module; and a lubricant disposed between the battery module and the cooler. The cooler has a refrigerant flow path for the flow of refrigerant (cooling water). The refrigerant flow path has a shape extending along one direction. The refrigerant flows from one end of the refrigerant flow path to the other end in one direction. Summary of the Invention

[0003] In the battery cell disclosed in Japanese Patent Application Publication No. 2020-53148, the temperature of the refrigerant flowing in the refrigerant flow path becomes higher towards the downstream side of the refrigerant flow path. Therefore, the cooling effect of the refrigerant on the individual cells decreases on the downstream side of the refrigerant flow path. Consequently, there is a concern that the temperature of the individual cells located upstream of the cooling flow path may fluctuate between the temperatures of the individual cells located downstream.

[0004] The purpose of this disclosure is to provide an energy storage device that can suppress temperature fluctuations between the energy storage cells disposed on the upstream side of a cooling flow path and the energy storage cells disposed on the downstream side.

[0005] According to one aspect of this disclosure, an energy storage device is equipped with: an energy storage module comprising a plurality of energy storage cells arranged side-by-side in one direction; a housing housing the energy storage module; a cooler disposed below the housing for cooling the energy storage module via the housing; and a heat transfer element disposed between a lower surface of the energy storage module and the housing, the cooler having a cooling flow path in which a refrigerant flows along the one direction; the energy storage module having: an upstream battery stack disposed upstream in the flow direction of the cooling flow path, comprising a portion of the plurality of energy storage cells; and a downstream battery stack disposed upstream in the flow direction. The downstream side of the battery stack includes energy storage cells other than those included in the upstream battery stack; and an intermediate plate disposed between the upstream battery stack and the downstream battery stack. The housing has a bottom wall disposed below the energy storage module, the bottom wall having a raised portion that protrudes towards the intermediate plate. The heat conduction member has: an upstream heat conduction portion disposed upstream of the raised portion in the flow direction between the upstream battery stack and the bottom wall; and a downstream heat conduction portion disposed downstream of the raised portion in the flow direction between the downstream battery stack and the bottom wall, the downstream heat conduction portion having a thickness smaller than that of the upstream heat conduction portion.

[0006] The above and other objects, features, aspects and advantages of the present invention will become clearer from the following detailed description of the invention, which is understood with reference to the accompanying drawings. Attached Figure Description

[0007] Figure 1 This is a perspective view that schematically illustrates the structure of an energy storage device according to one embodiment of the present disclosure.

[0008] Figure 2 It is an exploded 3D view of the energy storage device.

[0009] Figure 3 yes Figure 1 A cross-sectional view at line III-III.

[0010] Figure 4 It is a cross-sectional view that roughly shows the state before the energy storage module is placed in the lower housing. Detailed Implementation

[0011] Embodiments of the present disclosure will now be described with reference to the accompanying drawings. Furthermore, in the drawings referred to below, the same or equivalent components are given the same reference numerals.

[0012] Figure 1 This is a perspective view schematically illustrating the structure of an energy storage device according to one embodiment of the present disclosure. The energy storage device 1 is, for example, mounted in a vehicle.

[0013] like Figures 1-3 As shown, the energy storage device 1 is equipped with multiple energy storage modules 100, a housing 200, a cooler 300, a heat transfer component 400, and a pushing component 500.

[0014] like Figure 3 As shown, each energy storage module 100 has multiple energy storage cells 110 and a pair of end plates 120.

[0015] Multiple energy storage cells 110 are arranged side-by-side in one direction. An example of an energy storage cell 110 is a lithium-ion battery. Each energy storage cell 110 is formed as a cuboid. Figure 1 As shown, multiple energy storage modules 100 are arranged side by side in an orthogonal direction that is orthogonal to both the first direction and the up and down direction.

[0016] A pair of end plates 120 are disposed on both sides of a plurality of battery cells 110 in one direction. Each end plate 120 is made of metal (such as aluminum).

[0017] The housing 200 houses multiple energy storage modules 100. The housing 200 has a lower housing 201 and an upper housing 202 (see reference). Figure 3 Additionally, in Figure 1 and Figure 2 The upper shell 202 is omitted from the illustration.

[0018] The lower housing 201 has an opening at the top. The lower housing 201 is made of metal. The lower housing 201 has a bottom wall 210, a peripheral wall 220, a flange 230, and a partition wall 240 (see reference). Figure 2 ) and reinforced bracket 250.

[0019] The bottom wall 210 is positioned below multiple energy storage modules 100. For example... Figure 2 and Figure 3 As shown, a raised portion 212 is formed in the center of one direction of the bottom wall 210. The top of the raised portion 212 is flat.

[0020] The peripheral wall 220 rises from the periphery of the bottom wall 210 and surrounds the periphery of the plurality of energy storage modules 100.

[0021] The flange 230 has a shape that extends outward from the upper end of the peripheral wall 220.

[0022] like Figure 2As shown, the partition wall 240 separates a pair of adjacent energy storage modules 100 in an orthogonal direction. The partition wall 240 is connected to the peripheral wall 220 at both ends in one direction. That is, the partition wall 240 functions to reinforce the peripheral wall 220.

[0023] A reinforcing bracket 250 is disposed in one direction between the peripheral wall 220 and the energy storage module 100. The reinforcing bracket 250 reinforces the mounting of the energy storage module 100 relative to the bottom wall 210. Figure 3 As shown, the lower end of the reinforcing bracket 250 is connected to the bottom wall 210 by welding or the like. Figure 1 and Figure 2 As shown, the upper end of the reinforcing bracket 250 is fixed to the flange 230 by welding or the like.

[0024] like Figure 3 As shown, the upper housing 202 has an opening at the bottom. The upper housing 202, together with the lower housing 201, houses a plurality of energy storage modules 100. The upper housing 202 is made of metal.

[0025] like Figure 3 As shown, the cooler 300 is disposed below the housing 200 and cools the energy storage module 100 via the housing 200. The cooler 300 is in contact with the lower surface of the bottom wall 210. Preferably, a heat conduction member is provided between the cooler 300 and the bottom wall 210. The cooler 300 has a cooling flow path 302, in which a refrigerant (water, etc.) flows in one direction.

[0026] like Figure 2 and Figure 3 As shown, each energy storage module 100 has an upstream battery stack 101, a downstream battery stack 102, and an intermediate plate 103.

[0027] The upstream battery stack 101 is disposed on the upstream side of the flow direction of the cooling flow path 302. The upstream battery stack 101 includes a portion of the multiple energy storage cells 110 contained in the energy storage module 100.

[0028] The downstream battery stack 102 is disposed downstream of the upstream battery stack 101 in the flow direction. The downstream battery stack 102 includes all energy storage cells 110 included in the energy storage module 100, excluding those included in the upstream battery stack 101. In this embodiment, the number of energy storage cells 110 included in the downstream battery stack 102 is the same as the number of energy storage cells 110 included in the upstream battery stack 101. Figure 3 As shown, the downstream battery stack 102 gradually tilts relative to the bottom wall 210 as it moves towards the downstream side in the flow direction.

[0029] An intermediate plate 103 is disposed between the upstream battery stack 101 and the downstream battery stack 102. In other words, the intermediate plate 103 is disposed at the center of the energy storage module 100 in one direction, the upstream battery stack 101 is disposed upstream of the intermediate plate 103 in the flow direction, and the downstream battery stack 102 is disposed downstream of the intermediate plate 103 in the flow direction. Figure 3 As shown, the intermediate plate 103 is placed on the raised portion 212 of the bottom wall 210.

[0030] A heat-conducting component 400 is disposed between the lower surface of the energy storage module 100 and the housing 200. More specifically, the heat-conducting component 400 is disposed between the lower surface of each energy storage cell 110 and the upper surface of the bottom wall 210. The heat-conducting component 400 is composed of a lubricant or the like. Figure 2 and Figure 3 As shown, the heat conduction member 400 has an upstream heat conduction section 410 and a downstream heat conduction section 420.

[0031] The upstream heat conduction section 410 is disposed upstream of the cooling section 212 in the flow direction between the upstream battery stack 101 and the bottom wall 210. The upstream heat conduction section 410 has a substantially uniform thickness in one direction.

[0032] The downstream heat conduction section 420 is disposed downstream of the raised portion 212 in the flow direction between the downstream battery stack 102 and the bottom wall 210. The downstream heat conduction section 420 has a thickness smaller than that of the upstream heat conduction section 410. Figure 3 As shown, the thickness of the downstream heat conduction section 420 gradually decreases as it moves downstream in the flow direction. However, as long as the thickness of the downstream heat conduction section 420 is smaller than the thickness of the upstream heat conduction section 410, it can have a substantially uniform thickness in one direction. The raised portion 212 functions as a reference for the thickness of the upstream heat conduction section 410 and the downstream heat conduction section 420.

[0033] The pressing member 500 is a member that pushes the energy storage module 100 towards the bottom wall 210. The energy storage module 100 is installed on the housing 200 while being pressed towards the bottom wall 210 by the pressing member 500 in a manner that crushes the heat conduction element 400. The pressing member 500 has an upstream pressing portion 510 and a downstream pressing portion 520.

[0034] The upstream pushing part 510 pushes the upstream end (end plate 120) of the upstream battery stack 101 in the flow direction toward the bottom wall 210. The upstream pushing part 510 has an upstream bracket 512, a first upstream fastening member 514 and a second upstream fastening member 516.

[0035] The upstream side bracket 512 is a component used to mount the upstream battery stack 101 to the housing 200. The upstream side bracket 512 is made of metal. The inner end of the upstream side bracket 512 in one direction is secured to the upstream end (end plate 120) of the upstream battery stack 101 by a first upstream side fastening member 514. The outer end of the upstream side bracket 512 in one direction is secured to the upper end of the reinforcing bracket 250 by a second upstream side fastening member 516.

[0036] The downstream-side pressing portion 520 presses the downstream end (end plate 120) of the downstream battery stack 102 in the flow direction toward the bottom wall 210. The downstream-side pressing portion 520 presses the downstream end of the downstream battery stack 102 toward the bottom wall 210 such that the thickness of the downstream-side heat conduction portion 420 becomes smaller than the thickness of the upstream-side heat conduction portion 410. The downstream-side pressing portion 520 includes a downstream-side bracket 522, a first downstream-side fastening member 524, and a second downstream-side fastening member 526.

[0037] The downstream bracket 522 is a component used to mount the downstream battery stack 102 to the housing 200. The downstream bracket 522 is made of metal. The inner end of the downstream bracket 522 in one direction is secured to the downstream end (end plate 120) of the downstream battery stack 102 by a first downstream fastening member 524. The outer end of the downstream bracket 522 in one direction is secured to the upper end of the reinforcing bracket 250 by a second downstream fastening member 526.

[0038] Figure 4 This indicates the state before the intermediate plate 103 is placed on the raised portion 212 and the outer ends of each bracket 512, 522 are fastened. For example... Figure 4As shown, the dimension h2 between the downstream bracket 522 and the upper end of the reinforcing bracket 250 in the state before the intermediate plate 103 is placed on the raised portion 21, the inner end of the downstream bracket 522 is fixed to the end plate 120 by the first downstream fastening member 524, and the outer end of the downstream bracket 522 is fixed to the upper end of the reinforcing bracket 250, is larger than the dimension h1 between the upstream bracket 512 and the upper end of the reinforcing bracket 250 in the state before the intermediate plate 103 is placed on the raised portion 212, the inner end of the upstream bracket 512 is fixed to the end plate 120 by the first upstream fastening member 514, and the outer end of the upstream bracket 512 is fixed to the upper end of the reinforcing bracket 250. Furthermore, the fastening points of the first upstream fastening member 514 relative to the end plate 120 and the fastening points of the first downstream fastening member 524 relative to the end plate 120 are at the same height from the bottom wall 210. That is, the vertical dimension of the downstream bracket 522 is smaller than that of the upstream bracket 512 in the vertical direction. Therefore, when the second upstream fastening member 516 and the second downstream fastening member 526 are fastened, as... Figure 3 As shown, the thickness of the downstream heat conduction section 420 is smaller than the thickness of the upstream heat conduction section 410.

[0039] As described above, in the energy storage device 1 of this embodiment, since the thickness of the downstream heat conduction section 420 is smaller than the thickness of the upstream heat conduction section 410, the cooling amount of the refrigerant on the downstream battery stack 102 is increased. Therefore, fluctuations in the temperature between the energy storage cells 110 included in the upstream battery stack 101 and the energy storage cells 110 included in the downstream battery stack 102 are suppressed.

[0040] In the above embodiments, the reinforcing bracket 250 may also be omitted, and the outer ends of each bracket 512, 522 in one direction are fixed to the flange 230 of the housing 200, etc.

[0041] Alternatively, the upstream bracket 512 and the downstream bracket 522 may have the same shape, and the height of the fastening point of the first downstream fastening member 524 relative to the end plate 120 from the bottom wall 210 may be higher than the height of the fastening point of the first upstream fastening member 514 relative to the end plate 120 from the bottom wall 210.

[0042] Those skilled in the art can understand the above-described embodiments as specific examples of the following approaches.

[0043] The energy storage device in the above embodiments is equipped with: an energy storage module comprising a plurality of energy storage cells arranged side-by-side in one direction; a housing housing the energy storage module; a cooler disposed below the housing for cooling the energy storage module via the housing; and a heat transfer element disposed between the lower surface of the energy storage module and the housing. The cooler has a cooling flow path in which a refrigerant flows along the one direction. The energy storage module has: an upstream battery stack disposed upstream of the cooling flow path and comprising a portion of the plurality of energy storage cells; and a downstream battery stack disposed downstream of the upstream battery stack in the flow path. The downstream side of the battery stack includes battery cells other than those included in the upstream battery stack; and an intermediate plate disposed between the upstream battery stack and the downstream battery stack. The housing has a bottom wall disposed below the battery module, the bottom wall having a raised portion that protrudes towards the intermediate plate. The heat conduction member has: an upstream heat conduction portion disposed upstream of the raised portion in the flow direction between the upstream battery stack and the bottom wall; and a downstream heat conduction portion disposed downstream of the raised portion in the flow direction between the downstream battery stack and the bottom wall, the downstream heat conduction portion having a thickness smaller than that of the upstream heat conduction portion.

[0044] In this energy storage device, because the thickness of the downstream heat conduction section is smaller than that of the upstream heat conduction section, the cooling effect of the refrigerant on the downstream battery stack is increased. Therefore, fluctuations in the temperature of the individual cells contained in the upstream battery stack and the individual cells contained in the downstream battery stack are suppressed.

[0045] Furthermore, preferably, the thickness of the downstream heat conduction section gradually decreases as it moves downstream in the flow direction.

[0046] This more reliably suppresses temperature fluctuations between the cells contained in the upstream battery stack and the cells contained in the downstream battery stack.

[0047] Additionally, preferably, the energy storage device is further equipped with a pushing member for pushing the energy storage module toward the bottom wall. The pushing member has: an upstream pushing part that pushes the upstream end of the upstream battery stack in the flow direction toward the bottom wall; and a downstream pushing part that pushes the downstream end of the downstream battery stack in the flow direction toward the bottom wall. The downstream pushing part pushes the downstream end of the downstream battery stack toward the bottom wall in such a way that the thickness of the downstream heat conduction part becomes smaller than the thickness of the upstream heat conduction part.

[0048] Alternatively, the upstream pushing portion may include: an upstream bracket for mounting the upstream battery stack to the housing; a first upstream fastening member for fastening the upstream bracket to the upstream battery stack; and a second upstream fastening member for fastening the upstream bracket to the housing. The downstream pushing portion may also include: a downstream bracket for mounting the downstream battery stack to the housing; a first downstream fastening member for fastening the downstream bracket to the downstream battery stack; and a second downstream fastening member for fastening the downstream bracket to the housing. In this case, preferably, the dimension between the downstream bracket and the housing in the state before the intermediate plate is placed on the raised portion, the downstream bracket is fixed to the downstream battery stack by the first downstream fastening member, and the downstream bracket is fixed to the housing by the second downstream fastening member is larger than the dimension between the upstream bracket and the housing in the state before the intermediate plate is placed on the raised portion, the upstream bracket is fixed to the upstream battery stack by the first upstream fastening member, and the upstream bracket is fixed to the housing by the second upstream fastening member.

[0049] The embodiments of the present invention have been described above; however, the embodiments disclosed herein should be considered exemplary in all respects, not restrictive. The scope of the invention is given by the claims and is intended to include all modifications within the scope of the claims.

Claims

1. An energy storage device, wherein, Equipped with: An energy storage module comprising a plurality of energy storage cells arranged side by side in one direction; A housing that houses the energy storage module; A cooler, disposed below the housing, is used to cool the energy storage module via the housing; A pushing member that pushes the energy storage module toward the bottom wall; as well as A heat-conducting element is disposed between the lower surface of the energy storage module and the housing. The cooler has a cooling flow path, and the refrigerant flows in the cooling flow path in one direction. The energy storage module has: An upstream battery stack, which is configured on the upstream side of the flow direction of the cooling flow path, includes a portion of the multiple battery cells; A downstream battery stack, which is disposed downstream of the upstream battery stack in the flow direction, includes energy storage cells other than those included in the upstream battery stack among the plurality of energy storage cells. as well as An intermediate plate, wherein the intermediate plate is disposed between the upstream battery stack and the downstream battery stack, The housing has a bottom wall disposed below the energy storage module. The bottom wall has a raised portion that bulges towards the intermediate plate. The pushing member has: An upstream pushing section pushes the upstream end of the upstream battery stack toward the bottom wall in the flow direction; as well as The downstream pushing part pushes the downstream end of the downstream battery stack toward the bottom wall in the flow direction. The downstream pushing portion pushes the downstream end of the downstream battery stack toward the bottom wall in such a way that the thickness of the downstream heat conduction portion becomes smaller than the thickness of the upstream heat conduction portion. The upstream pushing part has: An upstream side bracket is used to mount the upstream battery stack onto the housing; A first upstream fastening member secures the upstream bracket to the upstream battery stack. as well as The second upstream fastening member secures the upstream bracket to the housing. The downstream pushing part has: A downstream side bracket for mounting the downstream battery stack onto the housing; A first downstream fastening member secures the downstream bracket to the downstream battery stack. as well as The second downstream fastening member secures the downstream bracket to the housing. The dimension between the downstream side bracket and the housing in the state before the intermediate plate is placed on the raised portion, the downstream side bracket is fixed to the downstream battery stack by the first downstream side fastening member, and the downstream side bracket is fixed to the housing by the second downstream side fastening member is larger than the dimension between the upstream side bracket and the housing in the state before the intermediate plate is placed on the raised portion, the upstream side bracket is fixed to the upstream battery stack by the first upstream side fastening member, and the upstream side bracket is fixed to the housing by the second upstream side fastening member. The heat-conducting element is made of a lubricant and has the following characteristics: An upstream heat conduction section is disposed on the upstream side of the bulge in the flow direction between the upstream battery stack and the bottom wall; as well as A downstream heat conduction section is disposed downstream of the raised portion in the flow direction between the downstream battery stack and the bottom wall. The downstream heat conduction section has a smaller thickness than the upstream heat conduction section. The thickness of the downstream heat conduction section gradually decreases as it moves downstream in the flow direction.

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