Secondary battery cell

Abstract

The utility model relates to a kind of secondary battery units, it has: unit shell;Electrode body, be housed in the unit shell;Electrolyte, be enclosed in the unit shell;And bag body, be configured between the electrode body opposite side wall of the unit shell and the electrode body, housing liquid including the additive of the electrolyte;The bag body has protruding convex shape towards the electrode body, and have the opening portion towards the upper direction in vertical direction.Adopting the utility model, the appropriate amount of additive can be easily supplied to the inside of unit shell according to the use condition of secondary battery unit.

Description

Technical Field

[0001] This utility model relates to a secondary battery unit. Background Technology

[0002] Japanese Patent Application Publication No. 2019-033045 discloses a non-aqueous electrolyte secondary battery. This non-aqueous electrolyte secondary battery includes a fluoroethylene carbonate supply mechanism that supplies fluoroethylene carbonate to the non-aqueous electrolyte when the internal pressure of the cell casing increases.

[0003] The additives contained in the electrolyte are consumed during the use of the secondary battery. Therefore, according to the secondary battery disclosed in Japanese Patent Application Publication No. 2019-033045, the additives may decrease before the internal pressure of the cell casing rises, resulting in a reduction in the performance of the secondary battery. Utility Model Content

[0004] This invention addresses the aforementioned technical problems and aims to provide a secondary battery cell that allows for easy supply of an appropriate amount of additives to the interior of the cell housing based on the usage of the secondary battery cell.

[0005] The secondary battery unit of this invention comprises: a unit housing; an electrode body housed within the unit housing; an electrolyte sealed within the unit housing; and a pouch disposed between the side wall of the unit housing opposite to the electrode body and the electrode body, containing a liquid containing an additive of the electrolyte. The pouch has a convex shape protruding toward the electrode body and an opening facing upward in the vertical direction.

[0006] According to this invention, since the additive is supplied as the electrode body expands, it is possible to easily supply an appropriate amount of additive to the interior of the cell housing according to the usage of the secondary battery cell. Attached Figure Description

[0007] Figure 1A and Figure 1B This diagram illustrates the schematic configuration of a secondary battery cell according to an embodiment.

[0008] Figure 2 This is a diagram illustrating the effect of the secondary battery unit in the embodiment. Detailed Implementation

[0009] The embodiments of this utility model are described with reference to the accompanying drawings.

[0010] Figure 1A and Figure 1B This diagram illustrates the schematic configuration of the battery cell 10 (secondary battery cell) according to this embodiment. Figure 1A and Figure 1BIn the diagram, the Z-direction is the height direction of the battery cell 10, which is parallel to the vertical direction. The X-direction is the direction of the short side of the cell housing 12, which is perpendicular to the Z-direction. The Y-direction is the direction of the long side of the cell housing 12, which is perpendicular to the Z-direction. More specifically, the X and Y directions are parallel to the horizontal direction. Figure 1A This is a perspective view of battery cell 10. Figure 1B This is a diagram showing the internal structure of the battery cell 10 as viewed from the Y direction.

[0011] The battery cell 10 is mounted on a vehicle, for example, as a battery module comprising multiple battery cells 10, to supply power to the vehicle. As an example, the battery cell 10 is a lithium-ion battery. The battery cell 10 includes a cell housing 12, an electrode body 14, a pair of external terminals 16 (positive external terminal and negative external terminal) and an electrolyte 18 (non-aqueous electrolyte).

[0012] The cell housing 12 is, for example, a square cell housing with a cuboid shape. That is, the battery cell 10 is, for example, a square cell. The cell housing 12 is, for example, formed of a metallic material such as aluminum.

[0013] One example is an electrode body 14 housed within the unit housing 12. The electrode body 14 is, for example, formed in a plate shape. Figure 1A As shown, the electrode body 14 is arranged, for example, with the X direction as its thickness direction. The electrode body 14 is formed to include a positive electrode and a negative electrode, with an electrolyte 18 held between the positive and negative electrodes. The electrode body 14 can be, for example, a wound electrode body, or a stacked electrode body. In addition, in the unit housing 12, for example, two or more electrode bodies 14 may be arranged with the X direction as their thickness direction.

[0014] A pair of external terminals 16 are electrically connected to the electrode body 14 via electrode tabs and collector terminals (not shown in the figure).

[0015] Furthermore, an electrolyte 18 is sealed within the unit housing 12. The electrolyte 18 contains an additive A. Depending on the composition of the negative electrode of the electrode body 14, additive A may be, for example, as shown below. Specifically, in the case of a negative electrode containing silicon oxide, fluoroethylene carbonate (FEC) may be an example of additive A. In the case of a negative electrode containing graphite, vinylene carbonate (VC), lithium bis(oxalato)borate (LiBOB), etc., may be examples of additive A.

[0016] Additive A contained in electrolyte 18 is consumed during the use of battery cell 10. As a result of consumption, the performance of battery cell 10 may decrease when additive A becomes less abundant; furthermore, if additive A is completely consumed, the performance of battery cell 10 will decrease drastically. On the other hand, if electrolyte 18 contains excessive additive A, a film is easily formed on the surface of electrode body 14, increasing the internal resistance of battery cell 10. Therefore, it is inappropriate to simply add a large amount of additive A to electrolyte 18 beforehand in order to suppress the performance degradation of battery cell 10.

[0017] Therefore, the battery cell 10 of this embodiment includes a pouch 20, which contains a liquid containing additive A of electrolyte 18. The term "liquid" here refers to, for example, the same electrolyte as electrolyte 18, but is not necessarily limited to that electrolyte. The pouch 20 is formed, for example, of a resin material (e.g., polypropylene) that is resistant to electrolytes.

[0018] The bag 20 is disposed between the side wall of the unit housing 12 opposite to the electrode body 14 and the electrode body 14. Figure 1B In the example shown, the sidewalls are two sidewalls 12a and 12b, respectively, opposite to the two sidewalls 14a and 14b of the electrode body 14. Sidewalls 14a and 14b are respectively sidewalls of the electrode body 14 orthogonal to the thickness direction (X direction) of the electrode body 14. That is, in Figure 1B In the example shown, the bag body 20 is located between the electrode body 14 and the unit housing 12 on each side in the X direction. The bag body 20 is mounted on the side walls 12a and 12b, for example.

[0019] Each bag 20 has a convex shape 20a protruding toward the electrode body 14. More specifically, when viewed from the Y direction (refer to...), Figure 1B Each convex shape 20a is a curved convex shape that protrudes in a curved manner from the sidewalls 12a and 12b toward the electrode body 14. Furthermore, as... Figure 1B As shown, each bag 20 has an opening 20b facing upward in the vertical direction (Z direction). More specifically, the opening 20b is provided, for example, at the upper part of each bag 20 in the vertical direction (the base end of the upper side of the convex shape 20a). Inside each bag 20, a liquid containing additive A is filled, for example, to the vicinity of the opening 20b.

[0020] Furthermore, although the illustrations are omitted here, similar to when viewing each bag 20 from the Y direction, when viewing each bag 20 from the Z direction, each bag 20 may also have a convex curve shape that protrudes in a curved manner from the side walls 12a and 12b toward the electrode body 14, respectively. In addition, in the Y direction, the opening 20b may, for example, be provided at the center of the unit housing 12 in the Y direction.

[0021] Alternatively, it can also be with Figure 1B In a different example, the pouch 20 is positioned between only one of the side walls 12a and 12b of the battery and the electrode 14. Alternatively, in an example where the cell housing 12 has multiple electrode bodies 14, the pouch 20 can also be positioned as described below. That is, the pouch 20 can also be positioned at least between one end of a plurality of electrode bodies 14 arranged in a horizontal direction (e.g., the X direction) and the side walls 12a and 12b of the cell housing 12 opposite to that electrode body 14.

[0022] Figure 2 This diagram illustrates the effect of the secondary battery unit 10 in this embodiment. If the battery unit 10 deteriorates due to use, sometimes... Figure 2 As shown in the upper section, electrode body 14 expands. More specifically, during expansion, electrode body 14 expands as shown in the upper section. Figure 2 As shown, the thickness (length in the X direction) increases in such a way that the center of the electrode body 14 in the Z direction (height direction of battery cell 10) expands the most.

[0023] As described above, in the battery cell 10 of this embodiment, pouches 20 containing a liquid containing additive A (e.g., an electrolyte containing additive A) are respectively disposed between the side walls 12a and 12b of the cell housing 12 and the electrode body 14. Furthermore, the pouches 20 have a convex shape 20a (more specifically, a convex curved shape) protruding toward the electrode body 14 and an opening 20b facing upward in the vertical direction. Thus, as... Figure 2 As shown in the lower section, as the electrode body 14 expands, the bag body 20 is pressed down by the electrode body 14, thereby releasing (i.e., supplying) additive A (more specifically, for example, an electrolyte containing additive A) from the opening 20b into the unit housing 12. As a result, the liquid level of the electrolyte 18 inside the unit housing 12 is restored. Furthermore, if the degree of expansion (increase in thickness) of the electrode body 14 increases, the amount of additive A released (supply) increases.

[0024] As described above, in the battery cell 10 according to this embodiment, additive A is supplied as the electrode body 14 expands. Therefore, an appropriate amount of additive A can be easily supplied to the interior of the cell housing 12 according to the usage of the battery cell 10. This contributes to a longer lifespan for the battery cell 10. In addition, the battery cell 10 according to this embodiment can realize an additive A supply mechanism composed of the electrode body 14 and the pouch 20 that utilizes the expansion of the electrode body 14.

[0025] Furthermore, the battery cell 10 according to this embodiment differs from the technology described in Japanese Patent Application Publication No. 2019-033045 in that additive A can be added (supplied) even if the internal pressure of the cell housing 12 does not increase. Therefore, the additive A supply mechanism can be realized without the need for sensors such as internal pressure sensors and control units.

Claims

1. A secondary battery cell, characterized in that, have: Unit housing; The electrode body is housed within the unit housing; The electrolyte is sealed inside the unit housing; and A bag body is disposed between the side wall of the unit housing opposite to the electrode body and the electrode body, and contains a liquid containing additives of the electrolyte; The bag body has a convex shape protruding toward the electrode body and has an opening facing upward in the vertical direction.

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