Battery cell

Abstract

The utility model provides a kind of battery unit, which can firmly engage between reinforcing plate and current collector plate in the battery module stacked with multiple electrode sheets.The battery unit comprises: a battery module stacked with multiple electrode sheets; a pair of current collector plates engaged at both ends of the battery module in a first direction in which the multiple electrode sheets are stacked; and a pair of reinforcing plates engaged with the pair of current collector plates from a direction opposite to the battery module in the first direction in which the multiple electrode sheets are stacked, the pair of current collector plates each having at least one groove formed on an engagement surface engaged with the reinforcing plate, the pair of reinforcing plates each having at least one protrusion formed on an engagement surface engaged with the current collector plate, and the at least one groove and the at least one protrusion are engaged with each other in the first direction in a non-detachable manner.

Description

Technical Field

[0001] This disclosure relates to a battery cell. Background Technology

[0002] Patent Document 1 describes a battery cell. The battery cell includes a battery module with multiple electrode sheets stacked on top of each other, a pair of current collectors connected to both ends of the battery module in a first direction in which the multiple electrode sheets are stacked, and a pair of reinforcing plates connected to the pair of current collectors in the first direction in which the multiple secondary battery cells are stacked, from the opposite direction to the battery module.

[0003] Patent document 1: International Publication No. 2020 / 241585.

[0004] Battery modules with multiple stacked electrode sheets typically have a generally flat, plate-like structure. In such modules, significant deflection can occur, for example, due to resonance, leading to reduced battery performance. As a countermeasure, a pair of reinforcing plates can be used to clamp the battery module and current collector. However, even with such a structure, if the reinforcing plates and current collector are not securely bonded, it is difficult to adequately suppress the deflection of the battery module and / or current collector. Utility Model Content

[0005] In view of the above, the present invention provides a battery cell that enables a strong connection between a reinforcing plate and a current collector in a battery module in which multiple electrode plates are stacked.

[0006] The battery cell disclosed herein includes: a battery module formed by stacking a plurality of electrode sheets; a pair of current collectors joined to both ends of the battery module in a first direction in which the plurality of electrode sheets are stacked; and a pair of reinforcing plates joined to the pair of current collectors in the first direction in which the plurality of electrode sheets are stacked, from a direction opposite to the battery module. The pair of current collectors each have at least one groove formed on a mating surface that is joined to the reinforcing plates, and the pair of reinforcing plates each have at least one protrusion formed on a mating surface that is joined to the current collectors. The at least one groove and the at least one protrusion are engaged with each other in an irremovable manner in the first direction.

[0007] In the above structure, the groove on the current collector plate and the protrusion on the reinforcing plate engage with each other. Specifically, the groove and the protrusion engage with each other in a non-detachable manner in a first direction, that is, in the direction in which the current collector plate and the reinforcing plate face each other. As a result, the current collector plate and the reinforcing plate are firmly bonded together, and even if the battery module may resonate, the deflection generated in the battery module and the current collector plate can be effectively suppressed.

[0008] In one embodiment of this disclosure, the protrusion may extend linearly on the mating surface of the manifold, and its cross-sectional shape includes a body portion protruding along the first direction and a locking portion protruding from the side of the body portion along a second direction intersecting the first direction. The groove may extend linearly on the mating surface of the reinforcing plate, and its cross-sectional shape corresponds to the cross-sectional shape of the protrusion.

[0009] According to the above structure, by sliding the reinforcing plate relative to the collector plate, the groove provided on the collector plate and the protrusion provided on the reinforcing plate can easily engage with each other.

[0010] In one embodiment of this disclosure, the at least one protrusion may be positioned at an antinode when the battery module and the pair of current collectors resonate. This structure allows for more effective suppression of deflection in the battery module and the pair of current collectors.

[0011] In one embodiment of this disclosure, an adhesive layer made of an insulating adhesive may be provided between the mating surface of the reinforcing plate and the mating surface of the current collector. According to this structure, electrical insulation can be achieved between the reinforcing plate and the current collector. Therefore, the material constituting the reinforcing plate can also be a conductive material, such as a metal.

[0012] In one embodiment of this disclosure, the pair of reinforcing plates may be made of a metallic material, and the at least one protrusion may be made of an insulating material. Even if the adhesive layer between the reinforcing plate and the manifold is made of an insulating adhesive, insulation may unexpectedly decrease at the point where the protrusion fits into the groove, for example, due to thinning of the adhesive layer. Therefore, if the protrusion is made of an insulating material, sufficient insulation can be ensured even at the point where the protrusion fits into the groove. Attached Figure Description

[0013] Figure 1 This is a perspective view showing the battery cell structure of an embodiment.

[0014] Figure 2 It is along Figure 1 The cross-sectional view of the battery module shown in section II-II is omitted from the illustration of a pair of reinforcing plates.

[0015] Figure 3 It means Figure 1 The enlarged cross-sectional view of part III of the battery cell shown, in which the protrusion of the reinforcing plate and the groove of the current collector are engaged with each other by an adhesive layer.

[0016] Figure 4 This is a diagram showing the reinforcing plate of the embodiment viewed from a vertically downward direction.

[0017] Figure 5 It means Figure 4 The VV cross-sectional view of the reinforcing plate shown. Detailed Implementation

[0018] Reference Figure 1 The following describes one embodiment of the battery cell 2. The battery cell 2 can be applied, for example, to a battery pack installed in a vehicle. This battery pack is a power source that supplies power to the vehicle's motor and may include one or more battery cells 2. The vehicle equipped with this battery pack can be an electric vehicle whose wheels are driven by an electric motor. Examples of electric vehicles mentioned here include battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs).

[0019] like Figure 1 As shown, battery unit 2 includes battery module 10, a pair of current collectors 20a and 20b, a pair of reinforcing plates 30a and 30b, and base 40. Base 40 is disposed below battery module 10. There are no particular limitations on the specific structure of base 40. For example, base 40 may also be attached to the frame of a vehicle (not shown in the figure).

[0020] In this description of the embodiment, for ease of explanation, as follows: Figure 1 The diagram defines the front-back, left-right, and up-down directions. However, the directions defined here do not limit the orientation of the battery cell 2 during manufacturing or use.

[0021] like Figure 2 As shown, the battery module 10 has multiple electrode plates 10a, 10b, 10c, multiple separators 18, and a package 11. The multiple electrode plates 10a, 10b, 10c and the multiple separators 18 are arranged alternately. That is, the multiple electrode plates 10a, 10b, 10c are stacked with the separators 18 in between. Each separator 18 is made of a material with electrical insulation properties and allows ions to pass through. The material constituting the separator 18 can be, for example, a single-layer or multi-layer structure of polyethylene. In the battery module 10, the multiple electrode plates 10a, 10b, 10c and the multiple separators 18 constitute multiple secondary battery cells C1, C2, C3. The multiple secondary battery cells C1, C2, C3 can be, for example, lithium-ion battery cells.

[0022] In a plurality of electrode plates 10a, 10b, and 10c, an electrolyte 17 is filled between adjacent electrode plates. The electrolyte 17 is, for example, liquid. The electrolyte 17 is not only filled in... Figure 2Within the range shown, it also fills the entire interior of the battery module 10. However, the electrolyte 17 is not limited to liquid; it can also be solid.

[0023] The package 11 is disposed along the periphery of the battery module 10. The package 11 is made of a material with electrical insulation properties. The material constituting the package 11 may be, for example, a resin such as polyethylene. The package 11 seals the electrolyte 17 within the battery module 10.

[0024] Next, the detailed structure of the multiple electrode sheets 10a, 10b, and 10c will be described. The multiple electrode sheets 10a, 10b, and 10c are rectangular sheets. Each electrode sheet 10a, 10b, and 10c includes multiple bipolar electrode sheets 10a and a pair of terminal electrode sheets 10b and 10c. The pair of terminal electrode sheets 10b and 10c are respectively disposed in the stacking direction of the multiple bipolar electrode sheets 10a (i.e.,...). Figure 2 The two ends of the paper (vertical direction).

[0025] Each of the plurality of bipolar electrode sheets 10a has a current collector foil 12, a positive electrode active material layer 13, and a negative electrode active material layer 14. The current collector foil 12 is a foil-shaped component. The current collector foil 12 has a positive electrode current collector foil (not shown) and a negative electrode current collector foil (not shown). The current collector foil 12 is integrally formed by laminating the positive electrode current collector foil and the negative electrode current collector foil. The positive electrode current collector foil is made of copper, for example, and the negative electrode current collector foil is made of aluminum, for example. However, the combination of the positive electrode current collector foil and the negative electrode current collector foil is not limited to this, and other combinations of metals can also be used. In a modified example, the current collector foil 12 may also be made of the same metal for both the positive electrode current collector foil and the negative electrode current collector foil.

[0026] The positive electrode active material layer 13 is disposed on the other side of the current collector foil 12. Figure 2 The side below the paper surface (hereinafter also referred to as the "bottom side"). The positive electrode active material layer 13 contains the positive electrode active material. As an example, the positive electrode active material is composed of a metal oxide containing lithium ions, such as lithium iron phosphate (LiFePO4:LFP). In addition to the positive electrode active material, the positive electrode active material layer 13 may also contain conductive additives, electrolytes, binders, and other components.

[0027] The negative electrode active material layer 14 is disposed on one side of the current collector foil 12. Figure 2 The upper side of the paper surface (hereinafter also referred to as the "upper side"). As an example, the negative electrode active material layer 14 is made of carbon materials such as graphite. In addition to the negative electrode active material, the negative electrode active material layer 14 may also contain conductive additives, electrolytes, binders, and other components.

[0028] A pair of terminal electrode sheets 10b and 10c include a positive terminal electrode sheet 10b and a negative terminal electrode sheet 10c. The positive terminal electrode sheet 10b has a positive current collector foil 15 and a positive active material layer 13. The structures of the positive current collector foil 15 and the positive active material layer 13 are the same as those of the positive current collector foil and the positive active material layer 13 in the bipolar electrode sheet 10a. The negative terminal electrode sheet 10c has a negative current collector foil 16 and a negative active material layer 14. The structures of the negative current collector foil 16 and the negative active material layer 14 are the same as those of the negative current collector foil and the negative active material layer 14 in the bipolar electrode sheet 10a.

[0029] Here, the upper surface 10d of the battery module 10 is divided into two regions 8a and 8b according to the relative positional relationship between the positive electrode active material layer 13 and the negative electrode active material layer 14. When viewed along the stacking direction, the upper surface 10d of the battery module 10 has a bipolar opposing region 8a and a bipolar non-opposing region 8b. The bipolar opposing region 8a is the region where the positive electrode active material layer 13 and the negative electrode active material layer 14 face each other. The bipolar non-opposing region 8b is located outside the bipolar opposing region 8a. Furthermore, the bipolar non-opposing region 8b is the region opposite to the negative electrode active material layer 14 but not opposite to the positive electrode active material layer 13. In other words, the cross-sectional area of ​​the negative electrode active material layer 14 is larger than the cross-sectional area of ​​the positive electrode active material layer 13. The "cross-sectional area" referred to here means the cross-sectional area when cut along a plane perpendicular to the stacking direction. With this structure, electrolysis on the negative electrode active material layer 14 during charging can be suppressed.

[0030] The structure of battery module 10 has been described in detail above, but this is only an example and does not limit the configuration of battery module 10. In battery unit 2 of this embodiment, the structure of battery module 10 is not limited to the above form and various modifications can be made.

[0031] like Figure 1 and Figure 2As shown, a pair of current collectors 20a and 20b are plate-shaped components. The pair of current collectors 20a and 20b are made of a metal such as aluminum and are conductive. The pair of current collectors 20a and 20b includes a lower current collector 20a and an upper current collector 20b. The lower current collector 20a is located on the lower side of the battery module 10 and is bonded to the bottom surface 10e of the battery module 10 via an adhesive layer 19. The adhesive layer 19 is made of a conductive adhesive, for example, to electrically connect the bottom surface 10e of the battery module 10 to the lower current collector 20a. The upper current collector 20b is located on the upper side of the battery module 10 and is bonded to the upper end surface 10d of the battery module 10 via the adhesive layer 19. The adhesive layer 19 is made of a conductive adhesive, for example, to electrically connect the upper end surface 10d of the battery module 10 to the upper current collector 20b. Here, the bottom surface 10e of the battery module 10 is one end face of the multiple electrode sheets 10a, 10b, and 10c in the stacking direction (first direction), and the top surface 10d of the battery module 10 is the other end face of the multiple electrode sheets 10a, 10b, and 10c in the stacking direction. That is, a pair of current collectors 20a and 20b are respectively connected to both ends of the battery module 10 in the stacking direction (first direction) of the multiple electrode sheets 10a, 10b, and 10c.

[0032] like Figure 1 As shown, the pair of reinforcing plates 30a and 30b are plate-shaped components. The pair of reinforcing plates 30a and 30b are made of metals such as aluminum, possessing a certain rigidity and strength. It should be noted that the pair of reinforcing plates 30a and 30b can also be made of insulating materials. The pair of reinforcing plates 30a and 30b includes a lower reinforcing plate 30a and an upper reinforcing plate 30b. The lower reinforcing plate 30a is located below the lower current collector 20a and is joined to the bottom surface 21a of the lower current collector 20a. The upper reinforcing plate 30b is located above the upper current collector 20b and is joined to the top surface 21b of the upper current collector 20b.

[0033] like Figure 3 As shown, an adhesive layer 25 composed of an insulating adhesive is provided between the bottom surface 31b of the upper reinforcing plate 30b (i.e., the mating surface of the upper current collector 20b) and the top surface 21b of the upper current collector 20b (i.e., the mating surface of the upper reinforcing plate 30b). This achieves electrical insulation between the upper current collector 20b and the upper reinforcing plate 30b. Although not shown, an adhesive layer composed of an insulating adhesive is also provided between the top surface 31a of the lower reinforcing plate 30a (i.e., the mating surface of the lower current collector 20a) and the bottom surface 21a of the lower current collector 20a (i.e., the mating surface of the lower reinforcing plate 30a). This also achieves electrical insulation between the lower current collector 20a and the lower reinforcing plate 30a.

[0034] like Figure 1 and Figure 3As shown, each of the pair of manifolds 20a and 20b has multiple slots 22a and 22b. The multiple slots 22a and 22b are respectively formed on the mating surfaces 21a and 21b of the pair of manifolds 20a and 20b that engage with the reinforcing plates 30a and 30b. On the other hand, each of the pair of reinforcing plates 30a and 30b has multiple protrusions 32a and 32b. The multiple protrusions 32a and 32b are respectively formed on the mating surfaces 31a and 31b of the pair of reinforcing plates 30a and 30b that engage with the manifolds 20a and 20b. The multiple slots 22a and 22b and the multiple protrusions 32a and 32b are interlocked in an irremovable manner in their opposite vertical direction (first direction).

[0035] According to the above structure, the current collectors 20a and 20b are firmly connected with the reinforcing plates 30a and 30b, which can effectively suppress the deflection of the battery module 10 and the current collectors 20a and 20b even if the battery module 10 may resonate.

[0036] Here, there are no restrictions on the specific shapes of the grooves 22a and 22b and the protrusions 32a and 32b. As an example, in this embodiment, the protrusions 32a and 32b have a certain cross-sectional shape and extend in a straight line. Figure 3 As shown, the cross-sectional shape of the protrusion 32b of the upper reinforcing plate 30b generally includes a body portion 33b and a locking portion 34b. The body portion 33b protrudes from the upper reinforcing plate 30b in the vertical direction (first direction), and the locking portion 34b protrudes from the side of the body portion 33b in the horizontal direction (second direction). With this structure, when the upper reinforcing plate 30b slides relative to the upper manifold 20b, the groove portion 22b formed on the upper manifold 20b and the protrusion 32b formed on the upper reinforcing plate 30b can easily engage with each other. As an example, the upper reinforcing plate 30b has two protrusions 32b, which have symmetrical cross-sectional shapes in the horizontal direction. Although not shown, the protrusion 32a of the lower reinforcing plate 30a also has the same cross-sectional shape.

[0037] In the battery cell 2 of this embodiment, there are no limitations on the number and arrangement of the slots 22a, 22b and the protrusions 32a, 32b. However, the slots 22a, 22b and the protrusions 32a, 32b are preferably located at the antinodes when the battery module 10 and the pair of current collectors 20a, 20b resonate. As an example, in the battery cell 2 of this embodiment, two sets of slots 22a and protrusions 32a are provided between the lower current collector 20a and the lower reinforcing plate 30a. These two sets of slots 22a and protrusions 32a are located at the antinodes when the battery module 10 and the pair of current collectors 20a, 20b resonate in a second-mode resonance. Similarly, two sets of slots 22b and protrusions 32b are also provided between the upper current collector 20b and the upper reinforcing plate 30b, and these two sets of slots 22b and protrusions 32b are also located at the antinodes when resonating in a second-mode resonance. This structure can more effectively suppress the deflection that occurs in the battery module 10 and the pair of current collectors 20a and 20b.

[0038] In the battery cell 2 of this embodiment, the pair of reinforcing plates 30a and 30b can be made of a metallic material. In this case, the protrusions 32a and 32b can be made of an insulating material. Even if the adhesive layer 25 between the current collectors 20a and 20b and the reinforcing plates 30a and 30b is made of an insulating adhesive, the insulation performance may unexpectedly decrease in the portion where the protrusions 32a and 32b are fitted with the grooves 22a and 22b, for example, due to the thinning of the adhesive layer 25. Therefore, if the protrusions 32a and 32b are made of an insulating material, sufficient insulation can be ensured even in the portion where the protrusions 32a and 32b are fitted with the grooves 22a and 22b.

[0039] In the battery cell 2 of this embodiment, there are no limitations on the structure in which the protrusions 32a and 32b are fixed to the reinforcing plates 30a and 30b. As an example, such as... Figure 4 and Figure 5 As shown, the protrusion 32a can be fixed to the lower reinforcing plate 30a by bolts 36. In this case, the protrusion 32a preferably has a countersunk hole 35. The countersunk hole 35 has an upper hole 35a formed on the upper surface of the protrusion 32a, and a lower hole 35c extending downward from the bottom surface 35b of the upper hole 35a. The bolt 36 passes through the countersunk hole 35 and is screwed into the threaded hole 35d of the lower reinforcing plate 30a. Thus, the threaded portion 36b of the bolt 36 engages with the threaded hole 35d of the lower reinforcing plate 30a, while the head 36a of the bolt 36 is received within the upper hole 35a of the countersunk hole 35. This structure prevents the head 36a of the bolt 36 from protruding from the upper surface of the protrusion 32a. Although not shown, the protrusion 32b can also be fixed to the upper reinforcing plate 30b by bolts 36 in the same way.

[0040] The technical examples disclosed in this specification have been described in detail above, but these are merely illustrative and not intended to limit the scope of the claims. The technology described in the claims includes various variations and modifications of the examples given above. The technical elements described in this specification or drawings can exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of application. Furthermore, the technology shown in this specification or drawings can achieve multiple objectives simultaneously, and the achievement of any one of these objectives itself has practical technical value.

Claims

1. A battery cell, characterized by, include: The battery module is composed of multiple electrode sheets stacked together; A pair of current collectors are joined to both ends of the battery module in a first direction in which the plurality of electrode sheets are stacked; as well as A pair of reinforcing plates are joined to the pair of current collectors in the first direction in which the plurality of electrode sheets are stacked, from a direction opposite to that of the battery module. The pair of manifolds each have at least one groove formed on the mating surface that engages with the reinforcing plate. The pair of reinforcing plates each have at least one protrusion formed on the mating surface that engages with the manifold. The at least one groove and the at least one protrusion engage with each other in an irremovable manner in the first direction.

2. The battery cell of claim 1, wherein, The protrusion extends linearly on the mating surface of the manifold, and its cross-sectional shape includes a body portion protruding along the first direction, and a locking portion protruding from the side of the body portion along a second direction intersecting the first direction. The groove extends in a straight line on the mating surface of the reinforcing plate, and its cross-sectional shape corresponds to the cross-sectional shape of the protrusion.

3. The battery cell of claim 1, wherein, The at least one protrusion is located at the antinode position when the battery module and the pair of current collectors resonate.

4. The battery cell of claim 1, wherein, An adhesive layer made of insulating adhesive is provided between the mating surface of the reinforcing plate and the mating surface of the current collector plate.

5. The battery cell of claim 4, wherein, The pair of reinforcing plates are made of metal, and the at least one protrusion is made of insulating material.

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