Battery device

Abstract

The application belongs to the technical field of batteries, and discloses a battery device, which comprises a bottom plate, a frame, a beam, a battery pack and an end plate. The frame is arranged on the bottom plate and forms a containing space with the bottom plate; the beam divides the containing space into multiple sub-containing spaces; at least one sub-containing space is provided with the battery pack, the battery pack comprises multiple battery monomers arranged in stacks, the height of the battery monomers is greater than the height of the beam; an end plate is arranged between the battery monomers at the end of the battery monomers in the stacking direction and the beam; the ratio of the height of the end plate to the height of the battery monomers is less than or equal to a, the value range of a is 0.8<=a<=1.2, the height range of the battery monomers is 50mm-300mm; the height of the beam is x millimeters, the thickness of the end plate is y millimeters, and x and y satisfy the relationship: 250<=x*y<=2280. The battery device provided by the application has high space utilization and low risk of lithium precipitation of the battery monomers.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a battery device. Background Technology

[0002] The battery assembly includes a frame and a battery pack housed within the frame. A beam is installed within the frame, and an end plate is positioned between the beam and the battery pack for securing the battery pack. To avoid obstructing the movement of functional components, the end plate is typically shorter than the battery pack. To ensure effective battery pack securing, the end plate needs to be relatively thick, resulting in a larger space occupied by the end plate and lower space utilization of the battery assembly. Furthermore, when the beam is impacted, the impact force is transmitted to the end plate, which can compress the battery pack, leading to lithium plating. Summary of the Invention

[0003] The purpose of this application is to provide a battery device to solve the technical problem of lithium plating in existing battery devices.

[0004] Based on the above concept, the technical solution adopted by this invention is as follows:

[0005] Battery device, including:

[0006] Base plate;

[0007] A frame, wherein the frame is disposed on the base plate and forms an accommodating space with the base plate;

[0008] The beam divides the accommodating space into multiple sub-accommodating spaces;

[0009] A battery pack, at least one of the sub-accommodating spaces is provided with the battery pack, the battery pack comprising a plurality of stacked battery cells, the height of the battery cells being greater than the height of the beam;

[0010] An end plate is provided between the battery cell and the beam at the end of the battery cell along the stacking direction of the battery cell;

[0011] The ratio of the height of the end plate to the height of the battery cell is less than or equal to a, where a ranges from 0.8 to 1.2, and the height of the battery cell ranges from 50mm to 300mm. The height of the beam is x millimeters, and the thickness of the end plate is y millimeters. x and y satisfy the relationship: 250 ≤ x × y ≤ 2280.

[0012] The beneficial effects that the above technical solution can achieve are:

[0013] By controlling the value of 'a' to satisfy the above range and the values ​​of x×y to satisfy the above relationship, the strength of the end plate fixing the battery pack can be guaranteed, reducing the risk of the battery pack moving relative to the base plate. It also reduces the risk of lithium plating in individual battery cells, improving the overall structural strength and safety of the battery device. Furthermore, the battery device has high space utilization, thereby increasing its energy density. If the value of 'a' is too large, it means the end plate is too high above the individual battery cells, affecting the connection between the individual cells and the busbar components. If the value of x×y is too large, the end plate thickness will be too large, occupying a large space and reducing the space for the battery pack, affecting the energy density of the battery device. If the beam is too high, the top of the individual battery cells will deform due to high stress, leading to lithium plating, which is detrimental to the safety performance of the battery device. If the value of x×y is too small, the end plate thickness will be too thin, affecting the fixing of the battery pack. The beam will exert a large force on the individual battery cells at the ends through the end plate, increasing the risk of lithium plating. If the beam height is too small, it will affect the fixing effect of the end plate, thus affecting the fixing effect of the battery pack and consequently the structural strength of the battery device. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a battery device provided in an embodiment of the present invention, without showing the battery pack;

[0016] Figure 2 This is a cross-sectional view of a portion of the structure of a battery device provided in an embodiment of the present invention;

[0017] Figure 3 This is a first structural schematic diagram of a battery pack provided in an embodiment of the present invention;

[0018] Figure 4 This is an assembly diagram of a single battery cell and an end plate provided in an embodiment of the present invention;

[0019] Figure 5 This is a side view of an end plate and a battery cell provided in an embodiment of the present invention;

[0020] Figure 6 This is a cross-sectional view of a battery pack provided in an embodiment of the present invention;

[0021] Figure 7 This is an embodiment of the present invention. Figure 6 The enlarged view of point A shown;

[0022] Figure 8 This is an assembly diagram of a battery cell and end plate provided in an embodiment of the present invention;

[0023] Figure 9 This is a schematic diagram of the second structure of a battery pack provided in an embodiment of the present invention.

[0024] In the picture:

[0025] 1. Base plate; 2. Frame; 3. Beam; 4. Battery pack; 41. Battery cell; 5. End plate; 51. Reinforcing rib; 52. Inner wall; 53. Outer wall; 6. Buffer pad; 7. Insulating plate; 8. Side plate; 9. Connecting seat; 10. Accommodation space. Detailed Implementation

[0026] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Furthermore, it should be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.

[0027] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. In the description of this embodiment, unless otherwise specified, "multiple" specifically refers to two or more.

[0031] In the description of this embodiment, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., are based on the orientation or positional relationships shown in the accompanying drawings and are only for ease of description and simplification of operation. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are merely used for distinction in description and have no special meaning.

[0032] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or it can be located in between the component.

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] This embodiment provides a battery device that has a high space utilization rate and can reduce the risk of lithium plating.

[0035] like Figures 1 to 9 As shown, the battery device includes a base plate 1, a frame 2, a beam 3, and a battery pack 4. The frame 2 is disposed on the base plate 1 and cooperates with the base plate 1 to form a receiving space 10 for accommodating the battery pack 4. The beam 3 is located within the receiving space 10 and divides the receiving space 10 into multiple sub-receiving spaces (not shown in the figure).

[0036] Optionally, the base plate 1, the frame 2, and the beam 3 can form a housing (not shown in the figure). The battery device can also include a cover (not shown in the figure) connected to the housing, with the housing and the cover cooperating to form a relatively sealed space. Of course, it is understood that the battery device may also not include a cover, and this embodiment does not limit this.

[0037] In this embodiment, the battery pack 4 is placed within at least one sub-accommodating space; that is, at least one sub-accommodating space is provided with the battery pack 4. For example, each sub-accommodating space contains one battery pack 4. Each battery pack 4 includes a plurality of stacked battery cells 41. The stacking direction of the battery cells 41 can be a direction parallel to the plane of the base plate 1. For example, the stacking direction of the battery cells 41 can be the length direction of the frame 2 or the width direction of the frame 2; this embodiment does not limit this.

[0038] In this embodiment, the battery cell 41 may include lithium-ion secondary battery cell, lithium-ion primary battery cell, lithium-sulfur battery cell, sodium lithium-ion battery cell, sodium-ion battery cell, magnesium-ion battery cell, nickel-metal hydride battery cell, nickel-cadmium battery cell, lead-acid battery cell, etc., but this embodiment is not limited to this.

[0039] A battery cell 41 typically includes a casing (not shown), a cell (not shown), and an electrolyte (not shown). The casing is used to house the cell and the electrolyte, and at least one positive electrode post (not shown) and at least one negative electrode post (not shown) are provided on the casing. The cell includes one or more electrode assemblies, which are formed by stacking or winding positive electrode plates, negative electrode plates, and separators.

[0040] The positive electrode typically includes a positive current collector and a positive active material layer. The positive active material layer is directly or indirectly coated on the positive current collector. The positive current collector without the positive active material layer protrudes from the positive current collector with the positive active material layer. The positive current collector without the positive active material layer serves as a positive electrode tab. Multiple positive electrode tabs are stacked together and electrically connected to the positive electrode post. For example, the multiple stacked positive electrode tabs can be directly soldered to the positive electrode post to form an electrical connection; alternatively, the battery cell may also include a positive electrode adapter piece. The multiple stacked positive electrode tabs are soldered to one end of the positive electrode adapter piece, and the other end of the positive electrode adapter piece is soldered to the positive electrode post, so that the positive electrode tabs and the positive electrode post form an electrical connection.

[0041] The negative electrode generally includes a negative current collector and a negative active material layer. The negative active material layer is directly or indirectly coated on the negative current collector. The negative current collector without the negative active material layer protrudes from the negative current collector with the negative active material layer. The negative current collector without the negative active material layer serves as a negative electrode tab. Multiple negative electrode tabs are stacked together and form an electrical connection with the negative electrode post. For example, the stacked negative electrode tabs can be directly welded to the negative electrode post to form an electrical connection; alternatively, the battery cell may also include a negative electrode adapter piece. The stacked negative electrode tabs are welded to one end of the negative electrode adapter piece, and the other end of the negative electrode adapter piece is welded to the negative electrode post, so that the negative electrode tabs and the negative electrode post form an electrical connection. The material of the separator is not limited; for example, it can be polypropylene or polyethylene.

[0042] In this embodiment, each battery pack 4 includes two battery cells 41 at its ends.

[0043] For example, such as Figure 2 As shown, the height of the battery cell 41 is greater than the height of the beam 3. The height direction of the battery cell 41 is perpendicular to the base plate 1, and the height direction of the beam 3 is also perpendicular to the base plate 1. The height direction of the battery cell 41 is the same as that of the beam 3. The greater height of the battery cell 41 than the beam 3 ensures that the beam 3, while fixing the battery cell 41, will not interfere with the electrical connection between the battery cell 41 and the busbar component (not shown in the figure), thus guaranteeing connection reliability. It should be noted that in this embodiment, the height of the battery cell 41 refers to its shoulder height, that is, excluding the height of the terminal post.

[0044] In some alternative embodiments, the multiple battery cells 41 of the battery pack 4 can be electrically connected through a busbar (e.g., a high- or low-voltage output device) to achieve parallel, series, or mixed connection of the multiple battery cells 41 in the battery pack 4. There can be one or more busbars, each used to electrically connect at least two battery cells 41.

[0045] In one embodiment, the height of the battery cell 41 ranges from 50mm to 300mm. For example, the height of the battery cell 41 is 50mm, 60mm, 80mm, 100mm, 120mm, 150mm, 180mm, 200mm, 220mm, 240mm, 250mm, 280mm, 300mm, etc.

[0046] like Figure 1As shown, the battery assembly also includes an end plate 5, which is provided between the end of the battery cell 41 and the beam 3 along the stacking direction of the battery cell 41. The end plate 5 is used to cooperate with the side plate 8 or cable ties to fix the battery pack 4 into a module, thereby improving the structural strength of the battery pack 4. The end plate 5 can be made of metal materials such as aluminum alloy and stainless steel, or it can be made of high-strength plastic; this embodiment does not limit this. In one embodiment, such as Figure 3 As shown, the end plate 5 and the side plate 8 cooperate to fix the battery pack 4.

[0047] In at least one embodiment, the ratio of the height of the end plate 5 to the height of the battery cell 41 is less than or equal to 'a', where the value of 'a' ranges from 0.8 to 1.2. Based on the value of 'a', the height of the end plate 5 can be greater than or less than the height of the battery cell 41. For example, the value of 'a' can be 0.8, 0.9, 0.95, 1, 1.1, 1.15, 1.2, etc.

[0048] In this embodiment, the height of beam 3 is x millimeters, and the thickness of end plate 5 is y millimeters. x and y satisfy the relationship: 250 ≤ x × y ≤ 2280, that is, the product of x and y is greater than or equal to 250 and less than or equal to 2280. For example, the value of x × y can be: 250, 260, 270, 280, 300, 350, 380, 400, 420, 450, 480, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2280, etc.

[0049] The battery device provided in this embodiment, by controlling the value of 'a' to satisfy the above-mentioned range and the values ​​of x×y to satisfy the above-mentioned relationship, can ensure the strength of the end plate 5 in fixing the battery pack 4, reduce the risk of the battery pack 4 moving relative to the base plate 1, and reduce the risk of lithium plating in the battery cells 41. This improves the overall structural strength and safety of the battery device, and the battery device has a high space utilization rate, thereby increasing the energy density of the battery device. If the value of 'a' is too large, it means that the end plate 5 is too high above the battery cells 41, which will affect the connection between the battery cells 41 and the busbar component. If the value of x×y is too large, the thickness of the end plate 5 will be too large, causing the end plate 5 to occupy a large space, thereby reducing the space for setting the battery pack 4 and affecting the energy density of the battery device. If the beam 3 is too high, the top of the battery cells 41 will deform due to large stress, resulting in lithium plating, which is detrimental to the safety performance of the battery device. If the value of x×y is too small, the thickness of the end plate 5 will be too thin, which will affect the fixation of the battery pack 4. Furthermore, the beam 3 will exert a large force on the battery cell 41 located at the end through the end plate 5, which will increase the risk of lithium plating in the battery cell 41. If the height of the beam 3 is too small, it will affect the fixation effect of the end plate 5, which in turn will affect the fixation effect of the battery pack 4, and thus affect the structural strength of the battery device.

[0050] In at least one embodiment, the ratio of the height of beam 3 to the height of end plate 5 is b, where b ranges from 0.5 to 1. Therefore, in this embodiment, the height of beam 3 is less than or equal to the height of end plate 5. When the value of b is within the range of 0.5 to 1, beam 3 provides better support to end plate 5, thereby improving the fixation effect of end plate 5 on battery cell 41. This prevents the battery cell 41 from cracking or excessively bulging due to expansion, reducing the risk of damage to the battery cell 41 and ensuring the safety performance of the battery device.

[0051] The value of b cannot be too large. If it is too large, it means that the height of beam 3 is greater than the height of end plate 5, while the height of battery cell 41 is greater than the height of beam 3. This would result in the height of end plate 5 being significantly less than the height of battery cell 41, leading to a smaller contact area between end plate 5 and the battery cell 41 located at the end, thus reducing the strength of end plate 5 in fixing battery pack 4. Conversely, the value of b cannot be too small. If it is too small, it means that the height of beam 3 is significantly less than the height of end plate 5, which would affect the support effect of beam 3 on end plate 5 and also affect the fixing strength of battery pack 4. For example, the value of b can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc.

[0052] In at least one embodiment, the height of the battery cell 41 ranges from 80mm to 200mm.

[0053] In one embodiment, when the height of the battery cell 41 is in the range of 80mm-200mm, x and y satisfy the relationship: 400≤x×y≤2280. When the height of the battery cell 41 is in the range of 80mm-200mm, x×y being greater than or equal to 400 and less than or equal to 2280 can ensure that the battery device has high energy density and space utilization, while also reducing the risk of lithium plating in the battery cell 41. This allows the battery device as a whole to meet the requirements of structural strength, high energy density, and high safety.

[0054] In one embodiment, the thickness of the end plate 5 ranges from 1mm to 20mm. When the thickness of the end plate 5 falls within this range, it allows for better fixation of the battery pack 4, reducing the risk of movement of the battery pack 4 relative to the base plate 1. Furthermore, the end plate 5 occupies less space, resulting in higher space utilization and energy density for the battery device. Additionally, the risk of lithium plating in the battery cells 41 due to compression by the end plate 5 is significantly reduced. Moreover, the thickness of the end plate 5 within this range also facilitates the installation of high and low voltage output components of the battery device. For example, the thickness of the end plate 5 can be 1mm, 3mm, 5mm, 7mm, 9mm, 10mm, 12mm, 14mm, 16mm, 18mm, 19mm, 20mm, etc.

[0055] In at least one embodiment, the height of beam 3 ranges from 40mm to 290mm. When the height of beam 3 falls within this range, it allows beam 3 to better support the end plate 5 and also reduces the risk of lithium plating in the battery cell 41. For example, the height of beam 3 can be 40mm, 60mm, 80mm, 100mm, 120mm, 140mm, 160mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, etc.

[0056] In at least one embodiment, the thickness of the beam 3, whose thickness direction is in the stacking direction of the battery cells 41, ranges from 10mm to 100mm. In this embodiment, the beam 3, whose thickness direction is in the stacking direction of the battery cells 41, can be referred to as a crossbeam, that is, the thickness of the crossbeam ranges from 10mm to 100mm. When the thickness of the crossbeam meets the specified range, the crossbeam has high structural strength and is not easily deformed in the event of a collision. Therefore, it can provide better support for the end plate 5, giving the end plate 5 high fixing strength to the battery pack 4, preventing the battery cells 41 from expanding and deforming, thereby reducing the risk of weld cracking in the battery cells 41, thus reducing the risk of lithium plating in the battery cells 41, and improving the structural strength and safety of the battery device.

[0057] The thickness of the crossbeam should not be too large, as this would occupy too much space in the containment space 10, which is not conducive to improving the energy density of the battery device. Conversely, the thickness of the crossbeam should not be too small, as this would fail to provide sufficient support for the end plate 5, potentially leading to cracking of the welds on the battery cells 41. For example, the thickness range of the crossbeam can be 10mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, or 100mm.

[0058] In at least one implementation, such as Figure 8 As shown, the end plate 5 is provided with reinforcing ribs 51. The end plate 5 includes an inner wall 52 that contacts the battery pack 4, and the reinforcing ribs 51 are located on the side of the inner wall 52 facing away from the battery pack 4. The reinforcing ribs 51 are used to improve the structural strength of the end plate 5, reduce the risk of deformation of the end plate 5 due to the compression of the beam 3, and also to better fix the battery pack 4. By setting the reinforcing ribs 51 on the side of the end plate 5 facing away from the battery pack 4, the reinforcing ribs 51 do not directly contact the battery pack 4. The battery pack 4 contacts the plate-shaped end plate 5, resulting in a larger contact area and improving the uniformity of fixing the battery pack 4 when the end plate 5 is fixed. Because the end plate 5 is provided with reinforcing ribs 51, the thickness of the end plate 5 can be appropriately reduced, thereby reducing the space occupied by the end plate 5. While ensuring the fixing effect on the battery pack 4 remains unchanged, the energy density of the battery device can be further improved.

[0059] In one embodiment, when the end plate 5 is provided with reinforcing ribs 51, x and y satisfy the relationship: 250≤x×y≤2000. When the value of x×y is within the range, the overall structural strength and safety of the battery device are improved.

[0060] In at least one embodiment, such as Figure 8 As shown, the inner wall 52 of the end plate 5 contacts the battery cell 41 located at the end. The end plate 5 may also include an outer wall 53 disposed opposite to the inner wall 52 in the stacking direction of the battery cell 41. A reinforcing rib 51 may be connected between the inner wall 52 and the outer wall 53, so that the reinforcing rib 51 can divide the space between the inner wall 52 and the outer wall 53 to form multiple energy-absorbing regions (not shown). The energy-absorbing regions can absorb the compressive force transmitted from the beam 3 to the end plate 5, so that the force exerted by the end plate 5 on the battery cell 41 is smaller, further reducing the risk of lithium plating in the battery cell 41. It is understood that the end plate 5 may also include a side wall (not shown) connected between the inner wall 52 and the outer wall 53, which is not limited in this embodiment.

[0061] In one possible implementation, the reinforcing rib 51 is inclinedly disposed in a plate shape between the inner wall 52 and the outer wall 53 to provide a high level of support and reinforcement. It is understood that the reinforcing rib 51 can also be strip-shaped; this embodiment does not limit this aspect.

[0062] In one embodiment, the ratio of the length of the reinforcing rib 51 in the height direction of the end plate 5 to the height of the end plate 5 ranges from 0.6 to 0.9. When the ratio of the length of the reinforcing rib 51 in the height direction of the end plate 5 to the height of the end plate 5 meets the range, the length of the reinforcing rib 51 in the height direction of the end plate 5 will not be too large or too small, so that the reinforcing rib 51 can enhance most of the structural strength of the end plate 5, thereby ensuring the effect of the end plate 5 in fixing the battery pack 4.

[0063] The ratio of the length of the reinforcing rib 51 in the height direction of the end plate 5 to the height of the end plate 5 cannot be too small. If it is too small, weak areas will appear at the top or bottom of the end plate 5, which will affect the effect of fixing the battery pack 4. When a weak area appears at the top of the end plate 5, it will also increase the risk of lithium plating in the battery cells 41 due to compression. For example, the ratio of the length of the reinforcing rib 51 in the height direction of the end plate 5 to the height of the end plate 5 can be 0.6, 0.7, 0.8, 0.9, etc.

[0064] In at least one implementation, such as Figure 4 As shown, the battery pack 4 also includes a buffer pad 6. The buffer pad 6 is located between two adjacent battery cells 41 and is used to buffer the force between the two battery cells 41, thereby improving the vibration resistance of the battery pack 4. The buffer pad 6 can also have a heat insulation function to reduce the thermal interference of one battery cell 41 to another battery cell 41.

[0065] It should be noted that the buffer pad 6 is typically disposed between the large surfaces of two battery cells 41. In one embodiment, the area of ​​the buffer pad 6 can be equal to the area of ​​the large surface of the battery cell 41, so that the force applied by the buffer pad 6 to the battery cell 41 can be more uniform. In other embodiments, the area of ​​the buffer pad 6 can be smaller than the area of ​​the large surface of the battery cell 41, and this embodiment does not limit this.

[0066] Optionally, the material of the cushioning pad 6 may include aerogel, silicone, polyurethane, etc., and this embodiment does not limit this.

[0067] In one embodiment, when a buffer pad 6 is provided between two battery cells 41, x and y satisfy the relationship: 250 ≤ x × y ≤ 1800. By providing the buffer pad 6, when the battery cell 41 expands, it can compress the buffer pad 6 located between the two battery cells 41, thereby reducing the force exerted by the battery cell 41 on the end plate 5. Therefore, when x × y satisfies the relationship, it can ensure a good fixing effect on the battery pack 4. Furthermore, when the end plate 5 compresses the battery cell 41 located at the end, it can be buffered by the buffer pad 6 to reduce the risk of the battery cell 41's casing cracking or excessive bulging.

[0068] In at least one embodiment, a buffer pad 6 is provided between any two adjacent battery cells 41. This arrangement allows for cushioning between any two adjacent battery cells 41 via the buffer pad 6, reducing the risk of the casing of each battery cell 41 cracking due to compression, thereby reducing the risk of lithium plating in each battery cell 41 and improving the safety performance of the battery device.

[0069] In some implementations, the thickness of the buffer pad 6 ranges from 1mm to 6mm. When the thickness of the buffer pad 6 is within this range, the buffer pad 6 can achieve a buffering effect. Furthermore, the buffer pad 6 will not occupy too much space in the accommodating space 10, allowing the accommodating space 10 to have more space to accommodate the battery cells 41, thus ensuring the space utilization and energy density of the battery device.

[0070] The thickness of the buffer pad 6 cannot be too small, as this will affect the buffering effect and may cause adjacent battery cells 41 to crack due to compression. The thickness of the buffer pad 6 cannot be too large, as this will reduce the energy density of the battery device. For example, the thickness of the buffer pad 6 can be 1mm, 2mm, 3mm, 4mm, 5mm, or 6mm.

[0071] In at least one implementation, such as Figure 6 and Figure 7 As shown, the battery pack 4 also includes an insulating plate 7. The insulating plate 7 is disposed between the end plate 5 and the battery cells 41 at the ends of the battery pack 4; that is, each battery cell 41 at the end is provided with an insulating plate 7 between it and the end plate 5. The insulating plate 7 serves to insulate the battery cells 41 at the ends from the end plate 5, reducing the risk of short circuit between the battery pack 4 and the end plate 5. The insulating plate 7 also serves to transmit the force between the end plate 5 and the battery cells 41 at the ends.

[0072] In one embodiment, the area of ​​the large surface of the insulating plate 7 is larger than the area of ​​the large surface of the end plate 5. That is, the insulating plate 7 has a portion that extends beyond the end plate 5. The portion of the insulating plate 7 that extends beyond the end plate 5 can also contact the battery cell 41 located at the end. This allows the insulating plate 7 to increase the force-bearing area of ​​the battery cell 41 at the end. Consequently, the insulating plate 7 can assist the end plate 5 in restraining the battery cell 41 located at the end, preventing the portion of the battery cell 41 at the end from expanding excessively beyond the top of the end plate 5, which could lead to weld cracking and reduce the risk of lithium plating.

[0073] It is understandable that the area of ​​the large surface of the insulating plate 7 can be smaller or equal to the area of ​​the large surface of the end plate 5, but this embodiment does not limit this.

[0074] Optionally, the insulating board 7 is made of an insulating material. For example, the insulating board 7 can be made of insulating materials such as polypropylene, polyimide, or polyamide ester.

[0075] In some optional embodiments, the thickness of the insulating plate 7 ranges from 0.5mm to 3mm. When the thickness of the insulating plate 7 is within this range, on the one hand, the insulation effect of the insulating plate 7 is guaranteed; on the other hand, the insulating plate 7 can have a certain structural strength to restrain the portion of the end battery cell 41 that extends beyond the end plate 5, thereby reducing the risk of weld cracking of the end battery cell 41; furthermore, the insulating plate 7 occupies a small space, which can meet the high energy density requirements of the battery device.

[0076] For example, the thickness of the insulating board 7 is 0.5mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.8mm, 3mm, etc.

[0077] In one embodiment, the positive electrode of the battery cell 41 includes a positive current collector and a positive active material layer disposed on the positive current collector. The positive active material layer is made of lithium nickel cobalt manganese oxide, and x and y satisfy the relationship: 600 ≤ x × y ≤ 2280. During the cyclic charging and discharging process of the battery cell 41, the active material lithium nickel cobalt manganese oxide in the positive electrode will undergo significant volume expansion. When x and y satisfy the relationship, the strength of the beam 3 and end plate 5 in fixing the battery pack 4 can be guaranteed, thereby suppressing excessive expansion of the battery cell 41 and avoiding weld cracking caused by excessive expansion of the battery cell 41, thus improving the structural strength and safety performance of the battery device.

[0078] In at least one embodiment, such as Figure 9 As shown, the battery pack 4 also includes a connector 9. The connector 9 is disposed on the top of the end plate 5 and is used for the input and output of electrical energy of the battery pack 4. Exemplarily, the connector 9 can be a high-voltage or low-voltage connector. In this embodiment, the end plate 5 serves both to fix the battery pack 4 and to provide a mounting point for the connector 9, thus having multiple functions.

[0079] The battery device provided in this embodiment has high structural strength, reduces the risk of weld cracking in the battery cell 41 due to extrusion, has high safety performance, and has high energy density.

[0080] In this embodiment, battery strength test and battery temperature rise test are used to test the structural strength and temperature rise of battery pack 4.

[0081] Battery strength test: During the test, different values ​​of a and x×y are given, and the structural strength of the battery pack 4 is tested for compliance with different values ​​of a and x×y. Examples of battery packs with a values ​​between 0.8 and 1.2 and x×y values ​​between 250 and 2280 are provided, as shown in Table 1, which lists 21 examples. Comparative examples of battery packs with a values ​​outside the 0.8-1.2 range and x×y values ​​outside the 250-2280 range are provided, with 4 comparative examples. For each example and each comparative example, 300 identical battery cells 41 are used, with 10 battery cells 41 grouped together and fixed with end plates 5 and side plates 8 to form battery packs 4, resulting in 30 battery packs 4. The battery packs 4 are placed on the base plate 1, and a beam 3 is installed on the side of the end plate 5 away from the battery cells 41 to fix it to the base plate 1. The ratio 'a' between the height of end plate 5 and the height of battery cell 41, the height of beam 3 is x mm, and the thickness of end plate 5 is y mm. Specific values ​​are shown in Table 1. The embodiment and comparative example are identical except for 'a' and x×y. The battery device is discharged to 0% SOC at 0.33C, then charged to 100% SOC at 1C. After standing for 10 minutes, it is discharged to 0% SOC again at 1C and left to stand for 10 minutes. This 1C charging and discharging cycle is repeated 200 times. The battery cells 41 in each battery pack 4 are then observed for cracking, damage, or bulging (bulging protrusions greater than 3 mm are considered bulging). If more than one (i.e., two or more) of the 30 battery packs 4 have these defects, they are considered unqualified. If the number of battery packs 4 with these defects is less than or equal to one, they are considered qualified.

[0082] Battery Temperature Rise Test: During the test, different values ​​of a and x×y were given, and the temperature rise rate of battery pack 4 was tested when the values ​​of a and x×y were different. Examples with a values ​​between 0.8 and 1.2 and x×y values ​​between 250 and 2280 are called implementation examples, as shown in Table 1, which provides 21 examples. Comparative examples with a values ​​outside the 0.8-1.2 range and x×y values ​​outside the 250-2280 range are given, with 4 comparative examples. For each implementation example and each comparative example, 100 identical battery cells 41 were taken, with 10 battery cells 41 grouped together and fixed with end plates 5 and side plates 8 to form battery pack 4. Battery pack 4 was placed on base plate 1, and a beam 3 was installed on the side of end plate 5 away from the battery cells 41 to fix it to base plate 1. The ratio of the height of end plate 5 to the height of battery cell 41 is 'a', the height of beam 3 is 'x' mm, and the thickness of end plate 5 is 'y' mm. Specific values ​​are shown in Table 1. The embodiment and comparative example are identical except for 'a' and 'x×y'. The battery pack is discharged to 0% SOC at 0.33C, left to stand for 60 minutes, and the temperature at this point is measured and recorded as 't1'. Then, it is charged to 100% SOC at 1C, and the temperature at this point is recorded as 't2'. The charging time is recorded as 'T'. The temperature rise rate of each battery pack 4 is calculated using the formula: Temperature Rise Rate = (t2 - t1) / T. This calculation is performed 10 times, and the average value is taken. If the temperature rise rate is greater than 1℃ / min, it is considered unqualified; if the temperature rise rate is less than or equal to 1℃ / min, it is considered qualified.

[0083] Table 1

[0084]

[0085] A comparison of the experimental data from Examples 1-21 with those from Comparative Examples 1-4 reveals that when 'a' is within a certain range and x and y satisfy the relationship, the temperature rise rate of battery pack 4 is relatively small, the fastening strength of battery cells 41 in battery pack 4 is good, and battery cells 41 do not crack or bulge excessively due to cyclic expansion. A comparison of the experimental data from Examples 18-21 reveals that when x×y satisfies the formula, excessively large beam 3 will affect the installation of the busbar components between adjacent battery packs 4; excessively small beam 3 will lead to a decrease in the overall strength of the battery device's casing; excessively large end plate 5 will lead to a decrease in the energy density of the battery device; and excessively small end plate 5 will affect the installation of the end connector 9 (e.g., high and low voltage output components) of battery pack 4.

[0086] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A battery device, characterized by, The application relates to a battery pack, comprising: a bottom plate (1); a frame (2) arranged on the bottom plate (1) and forming a containing space (10) with the bottom plate (1); a beam (3) separating the containing space (10) into multiple sub-containing spaces; a battery pack (4) arranged in at least one of the sub-containing spaces, the battery pack (4) comprising multiple battery monomers (41) arranged in stacks, the height of the battery monomers (41) being greater than the height of the beam (3); an end plate (5) arranged between the battery monomers (41) at the end in the stacking direction of the battery monomers (41) and the beam (3); the ratio of the height of the end plate (5) to the height of the battery monomers (41) is less than or equal to a, the value range of a is 0.8<=a<=1.2, the height of the battery monomers (41) ranges from 50 mm to 300 mm, the height of the beam (3) is x mm, the thickness of the end plate (5) is y mm, and x and y satisfy the relationship: 250<=x*y<=2280; the thickness of the end plate (5) ranges from 1 mm to 20 mm, and the height of the beam (3) ranges from 40 mm to 290 mm.

2. The battery device according to claim 1, characterized by The ratio of the height of the beam (3) to the height of the end plate (5) is b, and the value range of b is 0.5-1.

3. The battery device of claim 1, wherein The height of the battery monomers (41) ranges from 80 mm to 200 mm, and x and y satisfy the relationship: 400<=x*y<=2280.

4. The battery device of claim 1, wherein The thickness of the beam (3) in the stacking direction of the battery monomers (41) ranges from 10 mm to 100 mm.

5. The battery device of claim 1, wherein The end plate (5) is provided with a reinforcing rib (51), the end plate (5) comprises an inner wall (52) in contact with the battery pack (4), the reinforcing rib (51) is arranged on the side of the inner wall (52) away from the battery pack (4), x and y satisfy the relationship: 250<=x*y<=2000.

6. The battery device of claim 5, wherein The ratio of the length of the reinforcing rib (51) in the height direction of the end plate (5) to the height of the end plate (5) ranges from 0.6 to 0.

9.

7. The battery device of claim 1, wherein The battery pack (4) further comprises a buffer pad (6) arranged between two adjacent battery monomers (41), x and y satisfy the relationship: 250<=x*y<=1800.

8. The battery device of claim 7, wherein, The buffer pad (6) is arranged between any two adjacent battery monomers (41).

9. The battery device of claim 7, wherein, The thickness of the buffer pad (6) ranges from 1 mm to 6 mm.

10. The battery device of claim 1, wherein The positive pole tab of the battery monomer (41) comprises a positive pole current collector and a positive pole active material layer arranged on the positive pole current collector, the material of the positive pole active material layer is lithium nickel cobalt manganese oxide, x and y satisfy the relationship: 600<=x*y<=2280.

11. The battery device of claim 1, wherein The battery pack (4) further comprises an insulating plate (7) arranged between the end plate (5) and the battery monomers (41) at the end of the battery pack (4).

12. The battery device of claim 11, wherein, The thickness of the insulating plate (7) ranges from 0.5 mm to 3 mm.

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