Lid assembly for prismatic battery cells

Abstract

Provides a cover assembly for battery cells. [Solution] The lid assembly is configured to liquid-tightly close the internal compartment 3 of the battery cell and comprises a base plate 4 configured to close the opening 3a of the internal compartment 3, the base plate 4 having an injection hole 12 formed therein to allow injection of electrolyte material into the internal compartment 3, the lid assembly 1 further comprises a closure device 8 that seals the injection hole 12 in a liquid-tight manner, the closure device 8 comprises a closure element 10 connected to the base plate 4 at the injection hole 12, the closure element 10 having a substantially flat configuration and comprising at least two protrusions located on opposite sides of the closure element 10.

Description

Technical Field

[0009]

[0001] The present invention relates to a lid assembly for a prismatic battery cell, and more particularly to a lid assembly for closing and sealing liquid-tightly an internal compartment of a prismatic battery cell containing electrodes and electrolyte materials.

[0002] Battery cells are known and are used as electrical energy storage devices.

[0003] In particular, so-called primary batteries are known and are designed to be not easily rechargeable and thus to be discarded once used.

[0004] So-called secondary batteries are also known and are designed to be repeatedly recharged after each use cycle.

[0005] It is known that secondary-type batteries are used in various miniaturized portable electronic devices such as mobile phones, wristwatches, smartwatches, smart bands, etc. <​​​​​​​​​​​​​​​​​​A prismatic cell typically comprises a hollow prismatic housing (or case), which may have a parallelepiped shape, is usually made of a metal material, and has two electrodes (cathode and anode) housed inside the housing that form the internal compartment of the cell.

[0011] The internal compartment also houses a separator material electrically interposed between the two electrodes.

[0012] Within the internal compartment, the electrodes and separators are typically immersed in a liquid or gel-like electrolyte.

[0013] The battery cell also includes at least one lid assembly connected to the housing, sealing the internal compartment in a liquid-tight manner.

[0014] More specifically, the housing has at least one (rectangular) opening, usually located at the top, through which the electrodes and separators are inserted into the internal compartment. A lid assembly is attached to the housing to close this opening and thus seal the internal compartment. The lid assembly is generally, Generally, a metal base plate is positioned to fit and engage with the opening of the housing, thereby sealing the internal compartment. A current collector for each electrode, which is electrically connected to the electrode and configured to collect electrical energy from the electrode and to supply that electrical energy from the internal compartment to the external environment, A terminal member for each electrode, configured to receive a connector for a device that is electrically connected to an individual current collector, receives electrical energy therefrom, and is intended to be powered by a battery cell, and It is equipped with.

[0015] With respect to each electrode, the terminal members and current collectors are typically connected to one another (electrically and mechanically) using pins or rivets that engage with individual through-holes formed in the base plate.

[0016] In other words, the terminal components are located on the first outer side of the base plate, while the current collector is located on the second inner side of the base plate, opposite to the first side.

[0017] From the aforementioned perspective, the terminal members, pins, and current collectors together form the terminal assembly of the cover assembly. The terminal assembly has a longitudinal axis, and the pins are typically coaxial with this axis.

[0018] The lid assembly may comprise two or more such terminal assemblies.

[0019] A typical cover assembly also includes a first insulating member for each terminal assembly, which is inserted between the individual terminal member and the base plate to electrically insulate the terminal member from the base plate.

[0020] A typical cover assembly also includes a second insulating member for each terminal assembly, which is inserted between the individual current collector and the base plate to electrically isolate the current collector from the base plate.

[0021] During the assembly of the battery cell, the various components mentioned above are stacked axially and compressed together along the longitudinal axis of the terminal assembly.

[0022] According to known processes for manufacturing such battery cells, the internal compartment is filled with electrolyte material after the lid assembly is fitted into the housing, and especially after the base plate is welded to the opening in the housing.

[0023] For this purpose, the lid assembly is provided with a relatively small through-hole, commonly known as an "injection hole" for the electrolyte.

[0024] The injection hole is formed through the base plate and is used to inject the electrolyte material into the internal compartment after the lid assembly is connected to and fixed to the housing.

[0025] Therefore, the injection hole forms an opening in the base plate.

[0026] After the injection of the electrolyte, the injection hole must be sealed. For this purpose, the lid assembly generally includes a closing device having the following two components, which are a rubber sealing pin, and a cover or closing element formed by a generally shaped aluminum plate, respectively.

[0027] Generally, the injection hole includes a through-hole formed through the base plate and a recess formed in the base plate and surrounding this through-hole.

[0028] The sealing pin is usually mounted through interference engaging with the through-hole. At that time, the cover is placed on a dedicated seat formed by the recess and is welded thereto at the periphery that generally divides the recess in the lateral direction.

[0029] Therefore, the cover is disposed on top of the sealing pin.

[0030] During the assembly process of the lid assembly, it is known that the sealing pin elastically rebounds, so that the sealing pin slightly axially protrudes from the through-hole.

[0031] For this purpose, it is known to form the cover so as to raise the central portion of the sealing pin. Thereby, a space is formed between the cover and the base plate in the through-hole, and during use, the portion of the sealing pin that can protrude outside the through-hole can freely engage with that space.

[0032] As a result, the cover (or the closing element of the injection hole) protrudes from the recess, thereby increasing the aforementioned space as much as possible.

[0033] The dimensions need to be reduced and the protrusion from the base plate limited to avoid potential interference with other cells or other battery components.

[0034] At the same time, it is necessary to avoid complicating the manufacturing and assembly process of the lid assembly, minimizing additional work and time losses. [Overview of the Initiative] [Problems that the invention aims to solve]

[0035] The object of this invention is to provide a lid assembly for a prismatic battery cell that is not only reliable and cost-effective, but also solves at least some of the aforementioned drawbacks associated with known lid assemblies. [Means for solving the problem]

[0036] According to the present invention, this objective is achieved by the lid assembly described in claim 1.

[0037] This invention will be best understood by carefully reading the following description of preferred non-limiting embodiments, which are provided merely as examples with reference to the accompanying drawings. [Brief explanation of the drawing]

[0038] [Figure 1] This is a schematic exploded perspective view showing a battery cell equipped with a lid assembly according to the present invention, with components removed for clarity. [Figure 2A] This is an enlarged view showing the closing element of the electrolytic material injection hole in the lid assembly, and a top view with a portion removed for greater clarity. [Figure 2B] Figure 2A is a perspective view showing the closed element. [Figure 3]This is a cross-sectional view showing the injection hole area, including the injection hole and the injection hole closing device, with a portion removed for clarity. [Modes for carrying out the invention]

[0039] Referring to the attached Figure 1, reference numeral 1 indicates the cover assembly for the battery cell as a whole.

[0040] In particular, the battery cell is prismatic in shape and has a hollow prismatic housing 2, the housing forming an internal compartment 3 inside, and an opening 3a for accessing the internal compartment 3.

[0041] According to the embodiment shown herein, the housing 2 has the shape of a parallelepiped. Alternatively, the housing 2 may have any prism shape, such as a cube or a prism with a triangular base.

[0042] In this embodiment, the housing 2 may be cylindrical. In this case, the lid assembly 1 has a circular configuration.

[0043] This invention relates to a prismatic battery cell, but is not without general applicability.

[0044] In particular, this invention relates to a battery cell used in the automotive industry, for example, in a battery module for an electric vehicle or a hybrid vehicle, but it is not without general applicability.

[0045] The battery cell further comprises electrodes (cathode and anode, not shown), and the electrodes are housed in an internal compartment 3 together with a separator material (not shown) and an electrolyte material (not shown).

[0046] The electrolyte material may be in liquid or gel form.

[0047] The electrodes and separator material are inserted into the internal compartment 3 through the opening 3a.

[0048] As a result, the lid assembly 1 is connected to the housing 2 at the opening 3a and is configured to close the internal compartment 3 in a liquid-tight manner as required during normal use of the battery cell.

[0049] Therefore, the battery cell comprises a housing with electrodes, a separator, and an electrolyte, as well as a lid assembly 1.

[0050] The battery cell is preferably part of a battery module that includes multiple battery cells electrically connected to each other in parallel.

[0051] The housing 2 may have a further opening 3a opposite the aforementioned opening 3a, as shown in Figure 1. A further lid assembly 1 must be connected to the housing 2 to close the further opening 3a in a liquid-tight manner.

[0052] From this point forward, for the sake of brevity, we will refer to a single lid assembly 1.

[0053] As shown in Figure 1, the lid assembly 1 comprises a base plate 4 made of a metal material such as aluminum or stainless steel, and the base plate is configured to connect to the housing 2 at the opening 3a in order to close the opening 3a of the internal compartment 3, that is, it is designed to match the shape of the opening 3a and engage with the opening 3a to close the internal compartment 3.

[0054] The lid assembly 1 further comprises at least one terminal assembly 50, in particular two terminal assemblies 50, each configured to be electrically connected on its inside 5 to individual electrodes inside the internal compartment 3 to collect electrical energy from there, and on its outside 6 to a connector of a device (not shown) intended to be powered by a battery cell.

[0055] In particular, each terminal assembly 50 has a longitudinal axis X, A current collector 5 is formed inside the aforementioned terminal assembly 50 and configured to be electrically connected to the individual electrodes, A terminal member 6 is formed on the outside of the aforementioned terminal assembly 50 and configured to be electrically connected to the aforementioned connector, A pin 5b is inserted axially between the current collector 5 and the terminal member 6, and they are electrically connected to each other. It includes.

[0056] More specifically, pin 5b is welded to the terminal member 6 on its axial side and to the current collector 5 on the opposite axial side.

[0057] Preferably, the pin 5b is substantially cylindrical and is arranged coaxially with axis X.

[0058] The terminal assembly 50 extends axially from the internal compartment 3 to the external environment outside the internal compartment 3.

[0059] In detail, the terminal member 6 is positioned on the outside of the base plate 4 (i.e., the side facing the external environment) so as to be connected to the connector, and the collector 5 is positioned on the inside of the base plate 4 (i.e., the side facing the internal compartment 3) so as to be connected to the individual electrodes.

[0060] The base plate 4 is appropriately provided with a through hole 4a that is engaged by a pin 5b.

[0061] Pin 5b engages with terminal member 6, establishing an electrical connection between collector 5 and terminal member 6.

[0062] With the configuration described above, the current collector 5 and the terminal member 6 are positioned on opposite sides of the base plate 4 in the axial direction.

[0063] The cover assembly 1 may have two or more terminal assemblies 50. Two terminal assemblies 50 are shown in Figure 1. Hereafter, for simplicity, only one terminal assembly 50 will be considered.

[0064] The lid assembly 1 also preferably comprises an insulating member 7 inserted axially between the terminal member 6 and the base plate 4, electrically insulating the terminal member 6 from the base plate 4. The insulating member 7 is appropriately formed from an electrically insulating material such as PPS (polyphenylene sulfide) or PP (polypropylene).

[0065] The lid assembly 1 may include a gasket member, such as an O-ring, which is inserted between the base plate 4 and the terminal assembly 50 and configured to seal the internal compartment 3 in a liquid-tight manner from the external environment.

[0066] Preferably, the lid assembly 1 further comprises a stop frame 11 made of an electrically insulating material (e.g., synthetic plastic), which is known in itself and will not be described in detail.

[0067] The base plate 4 includes an inner surface 14 configured to face the internal compartment 3 when the base plate 4 is connected to the housing 2 (i.e., when the lid assembly 1 is fitted into the housing 2), and an outer surface 15 on the opposite side of the inner surface 14, configured to face outward from the internal compartment 3.

[0068] Lid assembly 1 is An injection port 12 that allows for the injection (or insertion) of electrolyte material into the internal compartment, A closure device 8 for sealing the injection hole in a liquid-tight manner, It also has the following features.

[0069] In fact, the injection hole 12 forms an opening through which the electrolyte material is inserted into the internal compartment 3 when the lid assembly 1 is connected to the housing 2; however, this is a known method and is not described in detail.

[0070] The closing device 8 comprises a closing element 10 preferably made of a metal material such as aluminum, which is preferably formed by a cover or plate.

[0071] The closing element 10 is connected to the base plate at the injection hole 12.

[0072] In detail, the sealing element 10 covers the injection hole 12, which is explained in detail below.

[0073] The closing element 10 is preferably formed as a disk-shaped body having a substantially circular profile.

[0074] In other words, according to this preferably non-limiting embodiment, the closing element 10 is formed by a circular, disc-shaped plate.

[0075] From this point forward, the closing element 10 may be referred to as "cover 10".

[0076] The closure device 8 preferably further comprises a sealing pin 13 that engages with the injection hole 12 in a liquid-tight manner.

[0077] The seal pin 13 is known and has not been described in detail.

[0078] The injection hole 12 has a central axis A and, as it proceeds radially from the inside to the outside, comprises at least one through hole 16 and a first recess 17 surrounding the through hole 16.

[0079] The through-hole 16 forms an opening for fluid communication with section 3, through which the electrolyte material is inserted.

[0080] The sealing pin 13 engages with the through-hole 16 in a liquid-tight manner to prevent the electrolyte material from leaking out or external substances from entering the compartment 3.

[0081] The cover 10 covers the through hole 16 and the first recess 17 and is connected to the base plate to completely cover the first recess 17 (and thus the through hole 16 as well).

[0082] According to an aspect of the present invention, the cover 10 has a substantially flat structure and is provided with at least two raised portions 18 located on the opposite side of the cover 10.

[0083] In particular, the cover 10 comprises a main (or central) portion 10a and a peripheral portion 10b, and the raised portion 18 protrudes vertically from the main portion 10a, thus forming a boss 18 that protrudes from the main portion 10a.

[0084] More specifically, the cover 10 comprises a first surface 19a facing the injection hole 12, particularly the first recess 17, and a second surface 19b opposite the first surface 19a. The cover 10 also comprises a first boss 18 located on the first surface 19a and a second boss 18 located on the second surface 19b.

[0085] Thus, the cover 10 is provided with at least one boss 18 protruding from each of the two surfaces 19a and 19b.

[0086] The presence of bosses 18 located on the opposite side of the cover 10, particularly on the individual axial surfaces 19a and 19b of the cover 10, allows for a significant improvement and streamlining of the manufacturing process of the lid assembly 1. In fact, the cover 10 is mass-produced, and once manufactured, is frequently stacked in a container such as a hopper, awaiting assembly onto the individual base plates 4.

[0087] The boss 18 significantly limits, and in particular completely eliminates, the risk of undesirable adhesion between the axial surfaces of two covers 10 that are adjacent to each other or accidentally come into contact with each other within the hopper.

[0088] In other words, the boss 18 acts as an element to prevent adhesion between the covers 10 during manufacturing.

[0089] This avoids the time and cost losses that would result from separating two or more covers that are fused together before the covers are assembled onto the individual base plates 4.

[0090] Advantageously, each boss 18 protrudes perpendicularly from the main portion 10a by a distance corresponding to 20-40%, preferably 25-35%, and more preferably 30% of the thickness of the main portion 10a.

[0091] For example, if the main portion 10a has a thickness of 0.5 mm, each boss protrudes from the main portion by a distance of 0.15 mm.

[0092] The applicant observed how these dimensions provide an optimal compromise between adhesion prevention effect and overall dimensions. In fact, these small dimensions allow the cover 10 to be positioned substantially coplanar with the outer surface 15 of the base plate 4.

[0093] Preferably, each boss 18 has a substantially circular shape.

[0094] This conformance is easiest to achieve during the manufacturing process. Therefore, the structure of the boss 18 does not significantly affect the total manufacturing and assembly time required for the lid assembly 1.

[0095] When the cover 10 is fitted onto the base plate, the cover 10 has a central axis B that is coaxial with the axis A of the injection hole 12.

[0096] Advantageously, the first boss 18 and the second boss 18 are positioned eccentrically on opposite sides of axis B.

[0097] The applicant observed how this "symmetrical" arrangement further enhances the prevention of adhesion with the other covers 10 during manufacturing.

[0098] In embodiments not shown herein, the boss 18 may not be arranged coaxially with respect to axis B.

[0099] In embodiments not shown herein, the boss 18 may be positioned coaxially with axis B.

[0100] As shown in Figures 2A, 2B, and 3, the cover 10 is A first recess 20 is positioned on the first surface 19a and forms a second boss 18 on the second surface 19b, A second recess 21 is positioned on the second surface 19b and forms the first boss 18 on the first surface 19a, It is equipped with.

[0101] Conveniently, the first boss 18 and the first recess 20 are positioned eccentrically and symmetrically on the first surface 19a on opposite sides with respect to the central axis B, and similarly, the second boss 18 and the second recess 21 are positioned eccentrically and symmetrically on the second surface 19b on opposite sides with respect to the central axis B.

[0102] Conveniently, the injection hole 12 also includes a second recess 22 surrounding the first recess 17.

[0103] The through hole 16, the first recess 17, and the second recess 22 are formed within the base plate 4.

[0104] As shown in Figure 3, the first recess 17 is formed deeper within the base plate 4 than the second recess 22.

[0105] Conveniently, the cover 10 is connected to the second recess 22, engages with the second recess 22, and overlaps the first recess 17.

[0106] In this way, the space 24 separated between the surface 19a of the cover 10 and the first recess 17 is increased, and the seal pin 13 can freely engage with the space even if it partially protrudes outside the through hole 16 during use. This reduces stress and strain on the seal pin 13 and ensures a precise liquid-tight seal during use.

[0107] Advantageously, the peripheral portion 10b of the cover 10 is welded to the base surface 23, particularly to the lower surface facing outward from the second recess 22.

[0108] For example, the applicant observed how welding to the base surface 23 of the second recess 22, instead of to the side surface of the second recess 22, leads to greater resistance of the seal and weld to thermal and mechanical stresses that the cover 10 experiences during use.

[0109] Advantageously, the cover 10 engages with the second recess 22 and becomes substantially flush with the outer surface 15 of the base plate 4.

[0110] Therefore, the presence of the bosses 18 allows for the creation and use of a flat cover 10, reducing unwanted excessive dimensions and protrusions of the base plate 4, thereby significantly limiting manufacturing time loss as the covers 10 do not adhere to each other during manufacturing and / or storage.

[0111] The features of the lid assembly 1 according to this invention lead to clear advantages, which can be obtained by using it.

[0112] In particular, the presence of bosses 18 located on the opposite side of the cover 10, and especially on each of the individual axial surfaces 19a and 19b of the cover 10, allows for a significant improvement and streamlining of the manufacturing process of the lid assembly 1. In fact, the cover 10 is mass-produced, and once manufactured, is frequently stacked in a container such as a hopper, awaiting assembly onto the individual base plates 4.

[0113] The boss 18 significantly limits, and in particular completely eliminates, the risk of undesirable adhesion between the axial surfaces of the two covers 10 that accidentally come into contact with each other within the hopper.

[0114] In other words, the boss 18 acts as an element to prevent adhesion between the covers 10 during manufacturing.

[0115] This avoids the time and cost losses that would result from separating two or more covers from each other before the covers can be assembled.

[0116] At the same time, this allows the substantially flat cover 10 to be used in close proximity to the injection hole 12, so that the cover 10 is substantially flush with the base plate 4, and therefore limits its undesirable protrusions and recesses as much as possible.

[0117] In addition, the reduction, and especially the substantial elimination, of unwanted protrusions and recesses (and thus sharp edges) from the outer surface 15 of the base plate 4 leads to further important technical effects, and in some cases, this outer surface 15 (and often the entire battery cell) is covered (except for the terminals 6) with a film of electrical insulating material. In the case of known types of closure elements and covers that have one or more prominent protrusions or recesses relative to the outer surface 15, and thus form sharp edges, the insulating film can be easily torn by the sharp edges or otherwise damaged. This is particularly observed when the battery cell is liquid-cooled, and is due to pressure oscillations or pulsations of the liquid itself.

[0118] The substantially flat configuration of the cover 10, with its minimized protrusions and recesses according to this invention, can limit or prevent damage to the insulating film, thereby reducing the risk of circuit short circuits and increasing the beneficial lifespan of the battery cells.

[0119] Finally, each lid assembly 1 described and illustrated individually is modifiable and can be altered without exceeding the scope of protection set forth in the appended claims. [Explanation of Symbols]

[0120] 1 ···Lid Assembly 2 ··· cabinet 3 ···Internal Compartments 3a...opening 4 ···Base plate 4a...Through hole 5 ···Current collector 5b ···pin 6. Terminal components 7. Insulating materials... 8 ···Closed devices 10 ···Closed element 10a ···Main part 10b ···Surrounding area 11 ···Stop frame 12...Injection hole 13 ···Seal pins 14 ···Inner self 15...External surface 16 ···Through hole 17 ···First recess 18 ···Elevated section, first boss, second boss 19a ···First side 19b ···Second side 20 ···First recess 21 ···Second recess 22 ···Second recess 23 ···Base surface 24...space 50... Terminal Assembly

Claims

1. A lid assembly (1) for a battery cell, comprising a base plate (4) configured to close an internal compartment (3) of the battery cell in a liquid-tight manner and to close an opening (3a) of the internal compartment (3), The base plate (4) is provided with an injection hole (12), which allows for the injection of electrolyte material into the internal compartment (3). The lid assembly (1) further comprises a closure device (8) for sealing the injection hole (12) in a liquid-tight manner, the closure device (8) includes a closure element (10) connected to the base plate (4) at the injection hole (12), The lid assembly (1) has a substantially flat structure and includes at least two protrusions (18) located on the opposite side of the closure element (10) itself.

2. The lid assembly (1) according to claim 1, wherein the closing element (10) comprises a main portion (10a), and the raised portion (18) protrudes vertically from the main portion (10a), thereby forming a boss (18) protruding from the main portion (10a).

3. The lid assembly (1) according to claim 2, wherein each raised portion (18) protrudes vertically from the main portion (10a) by a distance corresponding to 20-40%, preferably 25-35%, and more preferably 30% of the thickness of the main portion (10a).

4. The closing element (10) comprises a first surface (19a) facing the injection hole (12) and a second surface (19b) opposite to the first surface (19a), The lid assembly (1) according to any one of claims 1 to 3, wherein the closing element (10) comprises a first protrusion (18) disposed on the first surface (19a) and a second protrusion (18) disposed on the second surface (19b).

5. The lid assembly (1) according to claim 4, wherein the closing element (10) has a central axis (B), and the first protrusion (18) and the second protrusion (18) are eccentrically arranged on opposite sides of the central axis (B).

6. The closing element (10) is A first recess (20) is positioned on the first surface (19a) and forms the second raised portion (18) on the second surface (19b), A second recess (21) is positioned on the second surface (19b) and forms the first raised portion (18) on the first surface (19a), The lid assembly (1) according to claim 4 or 5, comprising:

7. The lid assembly (1) according to claim 5 or 6, wherein the first raised portion (18) and the first recess (20) are arranged symmetrically on the first surface (19a) with respect to the central axis (B) and the second raised portion (18) and the second recess (21) are arranged symmetrically on the second surface (19b) with respect to the central axis (B).

8. The lid assembly (1) according to any one of claims 1 to 7, wherein the injection hole (12) has a central axis (A) and, when advanced radially from the inside to the outside, comprises a through hole (16), a first recess (17) surrounding the through hole (16), and a second recess (22) surrounding the first recess (17), the first recess (17) being formed in the base plate (4) to be deeper in the axial direction than the second recess (22), and the closing element (10) comprises a main portion (10a) and a peripheral portion (10b), the peripheral portion (10b) being welded to the base surface (23) of the second recess (22).

9. The lid assembly (1) according to claim 8, wherein the base plate (4) has an outer surface (15), the injection hole (12) is formed on the outer surface, and the closing element (10) engages with the second recess (22) to be substantially coplanar with the outer surface (15) of the base plate (4).

10. Each raised portion (18) is roughly circular. and / or the closing element (10) is formed of a disk-shaped body having a substantially circular profile, and / or the closing device (8) further comprises a sealing pin (13) engaged with the injection hole (12) in a liquid-tight form, and / or the lid assembly (1) further comprises at least one terminal assembly (50) configured to be electrically connected on its inside (5) to individual electrodes inside the internal compartment (3) and on its outside (6) to a connector for a device intended to be powered by the battery cell, according to any one of claims 1 to 9.

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