Battery pack

Abstract

Conventional battery packs made it difficult to easily replace the battery cells. [Solution] The battery pack of the present invention comprises a plurality of battery cells 3, a battery storage section 12 for housing the plurality of battery cells 3, and a plurality of vibration suppression plates 4 that apply pressing force to the battery cells 3 in a direction that presses them against the bottom surface of the battery storage section 12. One vibration suppression plate 4 is provided for at least one of the plurality of battery cells 3 that are arranged in the row direction in which the plurality of battery cells 3 are stacked, and the plurality of vibration suppression plates 4 press down on all of the plurality of battery cells 3 housed in the battery storage section 12.

Description

Technical Field

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[0001] The present invention relates to, for example, a battery pack in which a plurality of battery cells are housed.

Background Art

[0002] Many battery packs for housing a plurality of battery cells in a battery case have been proposed. Therefore, a technique related to a battery pack for housing a plurality of battery cells is disclosed in Patent Document 1.

[0003] The battery pack described in Patent Document 1 includes a plurality of secondary batteries having external terminals at the bottom, a bus bar assembly including a connection board that electrically connects the external terminals of each of the secondary batteries and conducts heat from the external terminals, a case that disposes the bus bar assembly at the bottom and aligns the plurality of secondary batteries to connect and house them with the bus bar assembly, and a heat dissipation member disposed outside the case that dissipates the heat of the connection board to the outside of the case. Further, Patent Document 1 discloses that a battery cell housed in a case is pressed by a single vibration suppression plate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when a battery pack housed in a case is pressed by a single vibration suppression plate, there is a problem that it is difficult to replace only some of the battery cells because the pressing force is lost for all the battery cells in order to replace only some of the battery cells.

[0006] This invention has been made in view of the above circumstances, and aims to provide a battery pack that allows for easy replacement of battery cells. [Means for solving the problem]

[0007] One embodiment of the battery pack according to the present invention comprises a plurality of battery cells, a battery storage section for housing the plurality of battery cells, and a plurality of vibration suppression plates that apply a pressing force to the battery cells in a direction that presses them against the bottom surface of the battery storage section, wherein one vibration suppression plate is provided for at least one of the plurality of battery cells arranged in the row direction in which the plurality of battery cells are stacked, and the plurality of vibration suppression plates press down on all of the plurality of battery cells housed in the battery storage section. [Effects of the Invention]

[0008] The present invention provides a battery pack that allows for easy replacement of battery cells. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a battery pack according to Embodiment 1. [Figure 2] This is a cross-sectional view of the battery pack along line II-II in Figure 1. [Figure 3] This is a cross-sectional view illustrating the structure of a battery cell according to Embodiment 2. [Figure 4] This is a cross-sectional view illustrating the structure of a vibration suppression plate according to Embodiment 3. [Modes for carrying out the invention]

[0010] For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numeral, and redundant explanations have been omitted where necessary.

[0011] Embodiment 1 Figure 1 shows a schematic diagram of the battery pack 1 according to Embodiment 1. As shown in Figure 1, in the battery pack 1 according to Embodiment 1, a plurality of battery cells 3 are housed in a lower case 2, and the housed battery cells 3 are fixed inside the lower case 2 by pressing them against the bottom surface of the lower case 2 with a vibration suppression plate 4. In Figure 1, a bolt 14 used to fix the vibration suppression plate 4 to the lower case 2 is shown.

[0012] In Figure 1, to illustrate the storage of battery cells 3 in the lower case 2, two battery cells 3 are shown as a pair and stored in the lower case 2. However, the battery cells 3 stored in the lower case 2 are assembled into a battery stack shape, where one row of battery cells 3 (14 battery cells 3 in the example of Figure 1) are connected by busbar components, and then each battery stack is stored in the lower case 2. Also, in Figure 1, an example is shown where two battery stacks are stored in two rows in one lower case 2, but the number of rows of battery stacks stored in the lower case 2 can be changed as appropriate depending on the specifications of the battery pack 1. In the following explanation, the direction in which the battery cells 3 are stacked is referred to as the row direction, and the direction in which the battery stacks are arranged is referred to as the column direction, with the column direction being perpendicular to the row direction.

[0013] The lower case 2 is composed of a lower case tab 10, which is integrally molded with a heat sink 20 (described later) and resin as an insert component. The heat sink 20 is positioned in the lower case tab 10 such that its heat dissipation surface is exposed to the outside of the battery storage section 12. A partition wall 11 is provided with the lower case tab 10 to separate the inside of the lower case tab 10 into the battery storage section 12 and the junction box storage section 13. Multiple battery cells 3 are housed in the battery storage section 12. A junction box, which is a circuit for inputting and outputting power from the multiple battery cells 3, is located in the junction box storage section 13. In Figure 1, the junction box itself is omitted. It is also possible to form conductive components that connect the junction box and the multiple battery cells 3, and heat dissipation sections that bring these conductive components into contact with the heat sink 20, in the lower case tab 10, but the conductive components located in the junction box storage section 13 and the heat dissipation sections formed therein are omitted from the illustration in Figure 1.

[0014] Furthermore, as shown in Figure 1, multiple heat conductive material filling sections and passages are formed on the bottom surface of the battery housing section 12. Each of the multiple heat conductive material filling sections is formed at a position corresponding to the electrode components attached to the battery cell 3, with a pond structure portion formed where the top surface of the heat dissipation protrusions formed on the back side of the heat dissipation surface of the heat sink plate 20 is exposed, and multiple walls are formed to surround the area where the top surface of the heat dissipation protrusions is exposed. The pond structure portion is filled with heat conductive material and is formed in a row in the direction in which the battery cells 3 are stacked. The passages are formed to extend in the row direction in areas adjacent to the multiple heat conductive material filling sections.

[0015] Here, as shown in Figure 1, the battery pack 1 according to Embodiment 1 includes a plurality of battery cells 3, a battery storage section 12 that houses the plurality of battery cells 3, and a plurality of vibration suppression plates 4 that apply a pressing force to the battery cells 3 in a direction that presses them against the bottom surface of the battery storage section 12. Each vibration suppression plate 4 is provided for at least one of the plurality of battery cells 3 arranged in the row direction. The battery pack 1 according to Embodiment 1 then uses the plurality of vibration suppression plates 4 to press down on all of the plurality of battery cells 3 housed in the battery storage section 12. Furthermore, each of the multiple battery cells 3 according to Embodiment 1 has a smoke exhaust hole on the surface facing the vibration suppression plate 4 that discharges gas generated inside the cell case when the internal pressure of the cell case housing the electrode body exceeds a preset internal pressure limit. Each vibration suppression plate 4 has an opening in a part of its wall surface that opens to the smoke exhaust hole, and has a cylindrical smoke exhaust path that penetrates in the row direction in which the multiple battery cells 3 are stacked. The vibration suppression plate 4 will now be described in detail.

[0016] Figure 2 shows a cross-sectional view of the battery pack along the line II-II in Figure 1. In other words, Figure 2 is a cross-sectional view illustrating the structure of the vibration suppression plate 4 according to Embodiment 1. Note that Figure 2 also shows the top cover 5, which was omitted from Figure 1. The top cover 5 is placed over the lower case 2 so as to cover at least a number of vibration suppression plates 4.

[0017] As shown in Figure 2, the lower case 2 has a heat sink 20 positioned on its bottom surface so that the heat dissipation surface is exposed, and a lower case tab 10 is formed from resin to include the heat sink 20. Then, the battery cell 3 is fitted into the battery storage section 12 of the lower case 2. Here, Figure 2 illustrates the cross-sectional structure of the battery pack 1 in a region containing only one battery cell 3.

[0018] Furthermore, the example shown in Figure 2 illustrates a battery cell 3 having a structure in which two electrode bodies (for example, electrode bodies 30a and 30b) are housed in a cell case. The number of electrode bodies included in the battery cell 3 is not particularly limited. Also, while this cell case is molded from resin to include metal components such as electrodes, the molding method for the cell case is not particularly limited.

[0019] The electrode body 30a has a positive electrode terminal 31a and a negative electrode terminal 32a. The electrode body 30b has a positive electrode terminal 31b and a negative electrode terminal 32b. The battery cell 3 connects the negative electrode terminal 32a of the electrode body 30a and the positive electrode terminal 31b of the electrode body 30b with an intermediate terminal 33. And the battery cell 3 is configured such that at least the positive electrode terminal 31a of the electrode body 30a and the negative electrode terminal 32b of the electrode body 30b are exposed. Also, the battery cell 3 has smoke exhaust holes 34a and 34b for discharging gas generated inside the cell case when the internal pressure of the cell case that houses the electrode body on the surface facing the vibration suppression plate exceeds a preset internal pressure limit value. In the example shown in FIG. 2, the smoke exhaust hole 34a corresponds to the electrode body 30a side, and the smoke exhaust hole 34b corresponds to the electrode body 30b side. And in the battery pack 1 according to Embodiment 1, a plurality of battery cells 3 are connected in series by connecting the positive electrode terminal 31a and the negative electrode terminal 32b of adjacent battery cells 3 with bus bar components 21 and 22. And in the battery pack 1 according to Embodiment 1, a battery stack in which a plurality of battery cells 3 are connected in series is housed in the battery housing portion 12. In the battery pack 1 according to Embodiment 1, by attaching the vibration suppression plate 4 to the battery stack housed in the battery housing portion 12 in this way, each of the plurality of battery cells 3 is fixed by being pressed against the bottom surface of the battery housing portion 12. Note that the vibration suppression plate 4 is fixed to the lower case tab 10 by fastening components such as bolts.

[0020] As shown in Fig. 2, the vibration suppression plate 4 has an opening that opens to the smoke exhaust hole in a part of the wall surface, and has a cylindrical smoke exhaust path penetrating in the row direction in which a plurality of battery cells 3 are stacked. In Fig. 2, the smoke exhaust path 41a corresponding to the smoke exhaust hole 34a and the smoke exhaust path 41b corresponding to the smoke exhaust hole 34b are shown. The smoke exhaust path 41a is provided with an opening 411a in a portion facing the smoke exhaust hole 34a, and the smoke exhaust path 41b is provided with an opening 411b in a portion facing the smoke exhaust hole 34b. Further, the vibration suppression plate 4 is provided so as to be convex toward the corresponding battery cell 3, and has a pressing member that transmits a pressing force to the battery cell. In Fig. 2, a pressing member 42a that applies a pressing force to the cell case on the electrode body 30a side of the battery cell 3 and a pressing member 42b that applies a pressing force to the cell case on the electrode body 30b side of the battery cell 3 are shown. This pressing member is formed of, for example, an elastic member. Then, the contact pressure between the battery cell 3 and the bus bar component is maintained against the vibration applied to the battery pack 1 by the elastic force of the pressing member and the elastic force of the heat conductive agent disposed between the bus bar component and the heat dissipation plate 20. That is, it is preferable that the pressing member 42a is disposed on the vertical line of the positive terminal 31a, and the pressing member 42b is disposed on the vertical line of the negative terminal 32b.

[0021] From the above description, in the battery pack 1 according to Embodiment 1, by using a plurality of vibration suppression plates 4 that press the battery cells 3 against the bottom of the lower case 2, when partially replacing the battery cells 3, it does not affect the battery cells 3 other than the battery cell 3 to be replaced, and high maintainability can be realized.

[0022] Further, in the battery pack 1 according to Embodiment 1, by providing the smoke exhaust paths 41a and 41b in the vibration suppression plate 4, the smoke exhausted from the smoke exhaust holes 34a and 34b of the battery cell 3 does not directly hit the upper lid 5. Therefore, the thickness of the upper lid 5 can be made thin, and the battery pack 1 can be lightened.

[0023] Further, in the battery pack 1 according to Embodiment 1, by providing the smoke exhaust paths 41a and 41b, the smoke passes through a limited path, so that it can be discharged outside the battery pack while reducing the influence on other battery cells 3.

[0024] Embodiment 2 Embodiment 2 describes a modified battery cell 3a of the battery cell 3. In the description of Embodiment 2, components that are the same as those described in Embodiment 1 are denoted by the same reference numerals as in Embodiment 1 and their descriptions are omitted.

[0025] Figure 3 shows a cross-sectional view illustrating the structure of a battery cell 3a according to Embodiment 2. As shown in Figure 4, in the battery cell 3a according to Embodiment 2, reinforcing members 35a and 35b are provided on the wall that constitutes the surface of the cell case facing the smoke exhaust holes 34a and 34b to increase the wall strength. These reinforcing members 35a and 35b can be provided on the surface of the case wall, but for example, the length of a part of the positive electrode terminal 31a may be increased and the cell case may be molded so that the extended portion is embedded in the wall.

[0026] In this way, by providing reinforcing members 35a and 35b, it becomes possible to reliably discharge smoke from the smoke exhaust holes 34a and 34b.

[0027] Embodiment 3 Embodiment 3 describes a vibration suppression plate 4a, which is a modified version of the vibration suppression plate 4. In the description of Embodiment 3, components that are the same as those described in Embodiments 1 and 2 are denoted by the same reference numerals as in Embodiments 1 and 2, and their descriptions are omitted.

[0028] Figure 4 shows a cross-sectional view illustrating the structure of the vibration suppression plate 4a according to Embodiment 3. As shown in Figure 4, the vibration suppression plate 4a according to Embodiment 3 has protrusions 43a and 43b on the inner walls of the smoke exhaust paths 41a and 41b. In the example shown in Figure 4, one protrusion is provided in each smoke exhaust path, but the number of protrusions provided in the smoke exhaust path can be changed as appropriate. The protrusions are molded integrally with other parts when the vibration suppression plate 4a is formed.

[0029] By providing the protrusions 43a and 43b, the surface area of ​​the walls of the exhaust paths 41a and 41b can be increased, thereby lowering the temperature of the exhaust smoke. In other words, in the battery pack having the vibration suppression plate 4a according to Embodiment 3, it is possible to lower the temperature of the exhaust smoke discharged outside the battery pack.

[0030] Furthermore, the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. The above invention can also be viewed from the perspectives described in the following appendix.

[0031] (Note 1) Multiple battery cells, A battery housing section for housing the aforementioned plurality of battery cells, The battery compartment has a vibration suppression plate that applies a pressing force to the battery cell in a direction that presses the battery cell against the bottom surface of the battery compartment, Each of the plurality of battery cells has a smoke exhaust hole on the surface facing the vibration suppression plate that discharges gas generated inside the cell case when the internal pressure of the cell case housing the electrode body exceeds a preset internal pressure limit value. The vibration suppression plate has an opening in a part of its wall surface that opens to the smoke exhaust hole, and the battery pack has a cylindrical smoke exhaust path that penetrates in the row direction in which the plurality of battery cells are stacked.

[0032] (Note 2) The vibration suppression plate is provided at least once for each of the plurality of battery cells arranged in the row direction. The battery pack as described in Appendix 1, wherein multiple vibration-suppressing plates hold down all of the multiple battery cells housed in the battery compartment.

[0033] (Note 3) The aforementioned smoke exhaust path is a battery pack as described in Appendix 1, further having a projection provided on the inner wall.

[0034] (Note 4) The battery pack according to Appendix 1, wherein each of the plurality of vibration suppression plates is provided so as to be convex toward the corresponding battery cell, and further comprises a pressurizing member that transmits a pressing force to the battery cell.

[0035] (Note 5) The battery pack described in Appendix 1, wherein each of the plurality of battery cells is provided with a reinforcing member to increase the wall strength of the wall that constitutes the surface facing the surface where the smoke exhaust hole is provided.

[0036] (Note 6) The reinforcing member is the battery pack described in Appendix 5, which is embedded in the wall.

[0037] (Note 7) The battery pack according to Appendix 1, further comprising a battery pack upper cover that covers a plurality of vibration suppression plates. [Explanation of Symbols]

[0038] 1 Battery pack 2 Lower Cases 3 battery cells 4 Vibration suppression plate 5 Top lid 10 lower case tabs 11 Bulkhead 12 Battery compartment 13 Junction box storage compartment 14 volts 20 Heat sink 21 Busbar parts 22 Busbar parts 30a, 30b electrode body 31a, 31b positive terminal 32a, 32b negative terminal 33 Intermediate terminal 34a, 34b Smoke exhaust hole 35a, 35b Reinforcement members 41a, 41b Smoke exhaust path 42a, 42b Pressurizing members 43a, 43b protrusions

Claims

1. Multiple battery cells, A battery housing section for housing the aforementioned plurality of battery cells, The battery compartment has a plurality of vibration suppression plates that apply a pressing force to the battery cell in a direction that presses the battery cell against the bottom surface of the battery compartment, The vibration suppression plate is provided at least once for one of the plurality of battery cells arranged in the row direction in which the plurality of battery cells are stacked. A battery pack in which the plurality of vibration-suppressing plates hold down all of the plurality of battery cells housed in the battery compartment.

2. Each of the plurality of battery cells has a smoke exhaust hole on the surface facing the vibration suppression plate that discharges gas generated inside the cell case when the internal pressure of the cell case housing the electrode body exceeds a preset internal pressure limit value. The battery pack according to claim 1, wherein each of the plurality of vibration suppression plates has an opening in a part of its wall surface that opens to the smoke exhaust hole, and has a cylindrical smoke exhaust path that penetrates in the row direction in which the plurality of battery cells are stacked.

3. The battery pack according to claim 2, wherein the exhaust path further has a projection provided on the inner wall.

4. The battery pack according to claim 2, wherein each of the plurality of vibration suppression plates is provided so as to be convex toward the corresponding battery cell, and further comprises a pressurizing member that transmits a pressing force to the battery cell.

5. The battery pack according to claim 2, wherein each of the plurality of battery cells is provided with a reinforcing member to increase the wall strength of the wall constituting the surface facing the surface on which the smoke exhaust holes are provided.

6. The battery pack according to claim 5, wherein the reinforcing member is embedded in the wall.

7. The battery pack according to claim 1, further comprising an upper cover that covers the plurality of vibration suppression plates.

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