Battery module and method for manufacturing the same

Abstract

To provide a battery module capable of suppressing reduction in energy density and improving durability.SOLUTION: A battery module includes: a battery cell laminate in which a plurality of battery cells 11a are laminated; a pair of plate-shaped members provided at both ends in a lamination direction of the battery cell laminate; a fluid cushion 14 arranged between the plurality of battery cells 11a; and a holder 22 for supporting a region 21 not facing the battery cells 11a of the fluid cushion 14.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a battery module and a method for manufacturing the battery module.

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, research and development on battery modules that contribute to energy efficiency have been carried out.

[0003] Patent Document 1 describes a battery system including a laminate including a plurality of battery cells laminated along a virtual reference axis. Here, the pack frame includes a first end plate and a second end plate, one or more fluid springs configured to hold fluid, one or more fluid pressure adjusting means for adjusting the fluid pressure in at least one fluid spring, and a control unit configured to control the one or more fluid pressure adjusting means. The stack is disposed between the first end plate and the second end plate. Each of the one or more fluid springs is disposed between the first end plate and the second end plate and is configured to apply pressure to at least one battery cell in a direction along the reference axis. Each fluid pressure adjusting means is connected to one or more fluid springs. Here, A) at least one of the fluid springs includes an elastic device, and each of the fluid pressure adjusting means is configured to generate or adjust a negative pressure in the fluid in the connected fluid spring when the connected fluid springs each hold fluid; and / or B) the control unit is configured to receive a safety check signal from at least one safety check sensor, the control unit further evaluates whether the received safety check signal can indicate a safety-critical situation, and based on the evaluation that the safety check signal can indicate a safety-critical situation, is configured to operate the fluid, and the fluid pressure adjusting means reduces the fluid pressure in the fluid spring.

Prior Art Documents

Patent Document

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the battery system of Patent Document 1 includes fluid pressure adjusting means, the energy density decreases. Therefore, in order to suppress the decrease in the energy density of the battery system, it is conceivable not to use the fluid pressure adjusting means.

[0006] However, as the battery cell expands during charging, the fluid spring contracts in the stacking direction of the battery cells and expands in a direction perpendicular to the stacking direction of the battery cells, the fluid pressure in the fluid spring increases. For this reason, when the charging and discharging of the battery cells are repeated, not only is the fluid spring likely to be damaged, but the end plate is also likely to be damaged, and the durability of the battery module decreases.

[0007] An object of the present invention is to provide a battery module capable of suppressing a decrease in energy density and improving durability.

Means for Solving the Problems

[0008] (1) A battery cell stack in which a plurality of battery cells are stacked, a pair of plate-like members provided at both ends in the stacking direction of the battery cell stack, a fluid cushion disposed between the plurality of battery cells, and a holder that supports a region of the fluid cushion that does not face the battery cells, a battery module comprising.

[0009] (2) The battery module according to (1), further comprising positioning components for positioning the holder, wherein the holder is integrated with the positioning components.

[0010] (3) The battery module according to (1) or (2), wherein there is a space between the side surface of the holder and the side surface of the battery cell.

[0011] (4) The battery module according to any one of (1) to (3), wherein the side surface of the holder on the side facing the battery cell is a concave curved surface.

[0012] (5) The battery module according to any one of (1) to (4), wherein the battery cell is provided with a tab lead, and the tab lead is disposed between adjacent holders.

[0013] (6) A method for manufacturing a battery module according to any one of (1) to (5), the method including: integrating a first member corresponding to the upper half of the holder, a second member corresponding to the lower half of the holder, and the battery cell in a stacking direction of the battery cell laminate to obtain a battery module precursor; and stacking the battery module precursor via the fluid cushion.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a battery module capable of suppressing a decrease in energy density and improving durability.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Best Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0017] FIG. 1 shows a battery module according to an embodiment of the present invention.

[0018] The battery module 10 includes a battery cell stack 11 in which a plurality of battery cells 11a are stacked, end plates 12 as a pair of plate-like members provided at both ends in the stacking direction of the battery cell stack 11, and a bind bar 13 as a restraining member for restraining the battery cell stack 11 between the pair of end plates 12. Here, the bind bar 13 is installed at two locations, upper and lower, in the figure. Here, the restraining pressure by the bind bar 13 is not particularly limited, but is, for example, 1.0 MPa or more and 2.5 MPa or less. A fluid cushion 14 is disposed between the plurality of battery cells 11a and between the battery cell 11a and the end plate 12.

[0019] Note that the fluid cushion 14 may not be disposed between the battery cell 11a and the end plate 12.

[0020] As shown in FIG. 2, the battery module 10 further includes a holder 22 that supports a region 21 not facing the battery cell 11a of the fluid cushion 14. For this reason, the durability of the battery module 10 is improved. Specifically, as the battery cell 11a expands during charging, the fluid cushion 14 contracts in the stacking direction of the battery cell stack 11 and expands in a direction perpendicular to the stacking direction of the battery cell stack 11. However, due to the rigidity of the holder 22, the fluid cushion 14 is less likely to be damaged. In addition, the expansion of the fluid cushion 14 is controlled, and the expansion pressure in the stacking direction of the battery cell stack 11 is canceled between adjacent fluid cushions 14, so that the holder 22 can be made thinner and lighter. Here, the holder 22 is composed of a first member 22a corresponding to the upper half and a second member 22b corresponding to the lower half with respect to the stacking direction of the battery cell stack 11.

[0021] The fluid cushion 14 is filled with a fluid 14b in an outer member 14a. The material constituting the outer member 14a is not particularly limited as long as it has elasticity that can follow the expansion and contraction accompanying the charge and discharge of the battery cell 11a. Examples include rubber, elastomer, and elastic resin. Examples of rubber include ethylene-propylene rubber, nitrile rubber, fluororubber, chloroprene rubber, and urethane rubber. Examples of elastomers include styrene-based elastomers and olefin-based elastomers. Examples of elastic resins include polypropylene and polyamide. The outer member 14a may have an aluminum film sandwiched by an elastic resin film. Thereby, gas permeation is suppressed. The fluid 14b may be either a liquid or a gas, but is preferably a gas because it easily follows the expansion and contraction accompanying the charge and discharge of the battery cell 11a.

[0022] The material constituting the holder 22 is not particularly limited as long as it is a material with high rigidity. Examples include resin.

[0023] Note that the region 21 that does not face the battery cell 11a of the fluid cushion 14 is in contact with substantially the entire region of the holder 22 when the plurality of battery cells 11a are fully charged, but is in contact with a partial region of the holder 22 when the plurality of battery cells 11a are not fully charged.

[0024] As shown in FIG. 3, in the battery module 10, a space S exists between the side surface 31 of the holder and the side surface 32 of the battery cell. Therefore, even when the expansion pressure of the region 21 that does not face the battery cell 11a of the fluid cushion 14 is applied to the holder 22 when the plurality of battery cells 11a are fully charged, it is difficult for an external force to be applied to the side surface 32 of the battery cell, and the side surface 32 of the battery cell 11a is less likely to be damaged.

[0025] In this specification and the claims, the upper surface or the lower surface means a plane substantially perpendicular to the stacking direction of the battery cell stack, and the side surface means a plane substantially perpendicular to the upper surface or the lower surface.

[0026] The side surface 31 of the holder is in the shape of a concave curved surface. Therefore, when the battery cell 11a contains a sulfide-based electrolyte, even if hydrogen sulfide gas is generated, a space for the battery cell 11a to expand is ensured.

[0027] As shown in FIG. 2, the battery module 10 further includes a positioning component 23 for positioning the holder 22, and the holder 22 is integrated with the positioning component 23. Therefore, the manufacturability of the battery module 10 is improved.

[0028] As shown in FIG. 2, the battery cell 11a includes an electrode laminate 24 wrapped by a laminate film 25 and a tab lead 26 protruding from the laminate film 25. The tab lead 26 is disposed between adjacent holders 22. For this reason, for example, when the battery cell 11a at full charge vibrates due to the vibration of the vehicle body and stress is generated in the tab lead 26, the tab lead 26 is supported by the region 21 not facing the battery cell 11a of the fluid cushion 14 and the holder 22, so that damage to the tab lead 26 is suppressed. Here, even when the battery cell 11a is not at full charge, the tab lead 26 is supported by the holder 22, so that damage to the tab lead 26 is suppressed. Further, since the holder 22 is disposed in the dead space between the tab leads 26, a decrease in the energy density of the battery module 10 is suppressed.

[0029] The electrode laminate 24 has a plurality of positive electrodes and a plurality of negative electrodes laminated via an electrolyte. Examples of the electrolyte include an electrolytic solution and a solid electrolyte, and the electrolytic solution is held by a separator.

[0030] The tab lead 26 may be either a positive electrode tab lead or a negative electrode tab lead. Here, the positive electrode tab lead is connected to the plurality of positive electrodes via a positive electrode tab. On the other hand, the negative electrode tab lead is connected to the plurality of negative electrodes via a negative electrode tab.

[0031] FIG. 4 shows a method for manufacturing the battery module 10.

[0032] First, a first member 22a and a second member 22b that are arranged at a predetermined interval and a fully charged battery cell 11a connected to a tab lead 26 are integrated to obtain a battery module precursor 41. Next, while positioning the holder 22 and the tab lead 26 by the positioning component 23, the battery module precursor 41 is laminated via the exterior member 14a. At this time, by gripping the first member 22a and the second member 22b of the battery module precursor 41, damage to the battery cell 11a is suppressed. Also, the holder 22 is constituted by the first member 22a and the second member 22b that constitute adjacent battery module precursors 41. Next, the exterior member 14a is filled with a fluid 14b to form a fluid cushion 14.

[0033] When integrating the first member 22a and the second member 22b and the battery cell 11a connected to the tab lead 26, for example, they are adhered with an adhesive.

[0034] Note that the exterior member 14a may be filled with the fluid 14b before laminating the battery module precursor 41.

[0035] The cell constituting the battery cell 11a is not particularly limited, and examples include solid battery cells such as all-solid-state lithium-ion battery cells and all-solid-state lithium metal battery cells, and non-aqueous electrolyte battery cells such as lithium metal battery cells. Among these, an all-solid-state lithium metal battery cell is preferable.

[0036] Hereinafter, the case where the cell constituting the battery cell 11a is an all-solid-state lithium metal battery cell will be described.

[0037] The all-solid-state lithium metal battery cell, for example, has a positive electrode current collector, a positive electrode composite layer, a solid electrolyte layer, a lithium metal layer, and a negative electrode current collector sequentially laminated.

[0038] The positive electrode current collector is not particularly limited, and examples include aluminum foil.

[0039] The positive electrode composite layer contains a positive electrode active material, and may further contain a solid electrolyte, a conductive assistant, a binder, etc.

[0040] The positive electrode active material is not particularly limited as long as it can occlude and release lithium ions. For example, LiCoO2, Li(Ni 5 / 10 Co 2 / 10 Mn 3 / 10 )O 2、 Li(Ni 6 / 10 Co 2 / 10 Mn 2 / 10 )O 2、 Li(Ni 8 / 10 Co 1 / 10 Mn 1 / 10 )O 2、 Li(Ni 0.8 Co 0.15 Al 0.05 )O 2、 Li(Ni 1 / 6 Co 4 / 6 Mn 1 / 6 )O 2、 Li(Ni 1 / 3 Co 1 / 3 Mn 1 / 3 )O 2、 LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, sulfur, etc. may be mentioned.

[0041] The solid electrolyte constituting the solid electrolyte layer is not particularly limited as long as it is a material capable of conducting lithium ions. For example, oxide-based electrolytes and sulfide-based electrolytes may be mentioned.

[0042] The negative electrode current collector is not particularly limited. For example, a copper foil may be mentioned.

[0043] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and the above embodiments may be appropriately modified within the scope of the gist of the present invention.

Explanation of Reference Numerals

[0044] 10 Battery module 11 Battery cell laminate 11a Battery cell 12 End plate 13 Binding bar 14 Fluid cushion 14a Exterior member 14b Fluid 21 Region 22 Holder 22a First member 22b Second member 23 Positioning part 24 Electrode laminate 25 Laminate film 26 Tab lead 31 Side surface of the holder 32 Side surface of the battery cell 41 Battery module precursor S Space

Claims

1. A battery cell stack in which a plurality of battery cells are stacked, A pair of plate-like members provided at both ends in the stacking direction of the battery cell stack, A fluid cushion disposed between the plurality of battery cells, A battery module comprising a holder that supports a region of the fluid cushion that does not face the battery cells.

2. Further comprising positioning components for positioning the holder, The battery module according to claim 1, wherein the holder is integrated with the positioning components.

3. The battery module according to claim 1 or 2, wherein there is a space between a side surface of the holder and a side surface of the battery cell.

4. The battery module according to claim 1 or 2, wherein a side surface of the holder facing the battery cell has a concave curved surface shape.

5. The battery cell includes a tab lead, The battery module according to claim 1 or 2, wherein the tab lead is disposed between adjacent holders.

6. A method for manufacturing the battery module according to claim 1 or 2, Integrating a first member corresponding to the upper half of the holder, a second member corresponding to the lower half of the holder, and the battery cell with respect to the stacking direction of the battery cell stack to obtain a battery module precursor; A method for manufacturing a battery module, comprising a step of stacking the battery module precursor through the fluid cushion.

Images