Battery pack and electrical apparatus

Abstract

Provided is a battery pack, comprising a box body (1), battery cells (2) and heat insulation pads (3). The box body (1) comprises a bottom plate (1.1) and support members (1.2) provided on the bottom plate (1.1). The battery cells (2) are arranged in the box body (1), end parts of each battery cell (2) are arranged on the support members (1.2), and a first main body part of each battery cell (2) comprises a first side wall (2.1) facing the bottom plate. Each heat insulation pad (3) is arranged on a first side wall (2.1), and a first channel (4) is arranged between the heat insulation pad (3) and the bottom plate (1.1), the heat conductivity coefficient of the heat insulation pad (3) being less than 0.1 W (m.K). The heat insulation pad (3) is provided on the first side wall of each battery cell (2), and the heat conductivity coefficient of the heat insulation pad (3) is less than 0.1 W (m.K). Therefore, when thermal runaway occurs in a certain battery cell (2), high-temperature gas from thermal runaway enters the first channel (4); and when flowing in the first channel (4) and making contact with adjacent battery cells (2), the high-temperature gas from thermal runaway is blocked by the heat insulation pad (3) to stop heat transfer, such that the temperature of the adjacent battery cells (2) does not rise sharply to cause thermal runaway, thereby avoiding spreading of thermal runaway.

Description

Battery packs and power devices

[0001] This application claims priority to Chinese patent application CN202310926564.7, filed on July 25, 2023, with the invention name “Battery Pack and Electrical Device”. The entire contents of the above Chinese patent application are incorporated into this application by reference. Technical Field

[0002] The present invention relates to the field of electrical equipment, and specifically provides a battery pack and an electrical device. Background Art

[0003] New energy vehicles (NEVs) have seen rapid growth in recent years due to their environmentally friendly and low energy consumption, prompting numerous automakers to engage in their R&D efforts. However, as batteries are a crucial component in NEVs, their quality significantly impacts their development, particularly safety. Reports of NEVs spontaneously igniting and catching fire are common, posing serious risks to human life and potentially even causing major fires.

[0004] In the field, exhaust channels are usually set up in the battery pack to allow the high-temperature gas caused by thermal runaway to be discharged out of the pack. However, the problem of controlled heat spread still exists, causing the entire battery pack to spontaneously combust.

[0005] Summary of the Invention

[0006] In order to solve the problem of thermal runaway spread in the prior art, the present invention provides a battery pack, comprising: a box body, a battery cell and a thermal insulation pad, the box body comprising a bottom plate and a support member arranged on the above-mentioned bottom plate; the battery cell is arranged in the above-mentioned box body, the end of the above-mentioned battery cell is arranged on the above-mentioned support member, and the first main body of the above-mentioned battery cell includes a first side wall facing the above-mentioned bottom plate; the thermal insulation pad is arranged on the above-mentioned first side wall, and a first channel is provided between the above-mentioned thermal insulation pad and the above-mentioned bottom plate, and the thermal conductivity coefficient of the above-mentioned thermal insulation pad is less than 0.1W / (mK).

[0007] By arranging a thermal insulation pad on the first side wall of the battery cell, and the thermal conductivity of the thermal insulation pad is less than 0.1W / (mK), when a battery cell experiences thermal runaway, the thermal runaway high-temperature gas enters the first channel. When the thermal runaway high-temperature gas flows in the first channel and contacts the battery cell adjacent to it, the heat transfer is blocked by the thermal insulation pad, so the temperature of the battery cell adjacent to it will not rise sharply and thermal runaway will occur, thereby avoiding the spread of thermal runaway.

[0008] In an optional technical solution of the present invention, the thermal insulation mat has a flame retardancy rating of V0 and a melting point greater than 1000°C. If a battery cell undergoes thermal runaway and spontaneously ignites, the thermal insulation mat can prevent the fire from spreading to adjacent battery cells, thereby preventing the entire battery pack from burning.

[0009] In an optional technical solution of the present invention, the thermal insulation pad is provided with multiple spaced-apart weak points along the length of the battery cell. A battery cell experiencing thermal runaway can discharge the thermal runaway gas into the first channel through the multiple weak points on the thermal insulation pad. Three to seven weak points can be spaced apart along the length of a thermal insulation pad. The ends of the thermal insulation pad overlap with the support member, ensuring that the first side wall of the battery cell 2 is completely covered by the thermal insulation pad, preventing the spread of thermal runaway.

[0010] In an optional technical solution of the present invention, the thermal insulation pad includes a second main body portion and a weakened portion, wherein the thickness of the weakened portion is smaller than the thickness of the second main body portion. The thickness of the weakened portion is set to be smaller than the thickness of the second main body portion, so that thermal runaway gas can break through the weakened portion and enter the first channel.

[0011] In an optional technical solution of the present invention, the thickness H1 of the weak portion and the thickness H2 of the second main body portion of the thermal insulation pad satisfy: 1mm≤H2≤5mm, 0≤H1≤1mm.

[0012] In an optional technical solution of the present invention, the thermal insulation pad includes a second main body and a weak portion, wherein the weak portion is a through hole. The weak portion is set as the through hole, and the thermal runaway gas can directly enter the first channel through the through hole.

[0013] In an optional technical solution of the present invention, the shape of the through hole may be rectangular, circular, triangular, hexagonal or irregular.

[0014] In an optional technical solution of the present invention, the through-hole is rectangular, and its length L1 and width L2 satisfy the following requirements: 20mm≤L1≤40mm, 0.1mm≤L2≤2mm. Designing the through-hole as an elongated rectangular hole allows high-pressure, high-temperature gas to easily enter the first channel through the through-hole when thermal runaway occurs in a battery cell. Once in the larger first channel, the gas is diluted, preventing it from passing through the through-hole and contacting adjacent battery cells.

[0015] In an optional technical solution of the present invention, the thermal insulation pad comprises aerogel and an outer membrane encapsulating the aerogel, wherein the outer membrane is insulating. Aerogel has excellent thermal and electrical insulation properties and a high melting point. Therefore, when placed on the first sidewall of a battery cell, it can prevent thermal runaway from spreading to adjacent battery cells.

[0016] In an optional technical solution of the present invention, a rubber strip is provided between the thermal insulation pad and the first side wall, and the thermal insulation pad can be bonded to the first side wall of the battery cell via the rubber strip.

[0017] In an optional technical solution of the present invention, the battery cells include edge seals, and at least two adhesive strips are disposed between the thermal insulation mat and the first sidewall, with the adhesive strips disposed on either side of the edge seal. By providing adhesive strips on either side of the edge seal to bond the thermal insulation mat to the battery cells, space is reserved for the edge seals. A single thermal insulation mat can cover the first sidewalls beneath two adjacent battery cells, with the edge seals of the two battery cells disposed between the two adhesive strips, with the edge seals of the two battery cells facing each other.

[0018] In an optional technical solution of the present invention, a fireproof layer is provided on the bottom plate, and the fireproof layer comprises a carbon ceramic material. The thermal runaway gas, upon entering the first channel, will contact the bottom plate. Providing the fireproof layer on the bottom plate can prevent the bottom plate from being damaged by the high-temperature thermal runaway gas.

[0019] In an optional technical solution of the present invention, the support member is provided with an air inlet and a second channel; the side wall of the housing is provided with a third channel and a first explosion-proof valve; the air inlet, the second channel, the third channel, and the explosion-proof valve are sequentially connected. Thermal runaway gas enters the first channel, contacts the support member, enters the second channel through the air inlet in the support member, then passes through the third channel connected to the second channel, and finally exits the battery pack through the explosion-proof valve.

[0020] In an optional technical solution of the present invention, the air inlet is provided on the side of the support member facing the bottom plate. This allows the thermal runaway gas to enter the second channel for exhaust only when the air pressure in the box reaches a certain level, impacting the bottom plate and exposing the air inlet on the support member facing the bottom plate. This avoids the risk of exhaust in non-thermal runaway conditions.

[0021] In an optional technical solution of the present invention, a second explosion-proof valve is provided on the housing, and the second explosion-proof valve is connected to the first passage. Thermal runaway gas entering the first passage can also be directly discharged out of the battery pack through the second explosion-proof valve on the housing.

[0022] The present invention further provides an electrical device, comprising the battery pack of the optional technical solution. The battery pack can prevent thermal runaway from spreading. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a perspective view of the inside of a battery pack;

[0024] FIG2 is a bottom view of FIG1 with the base plate and support members removed;

[0025] FIG3 is a front view of FIG1 without the bottom plate and the support member;

[0026] FIG4 is a schematic diagram of a thermal insulation pad and a rubber strip.

[0027] List of reference numerals: Box body 1, bottom plate 1.1, support member 1.2; Battery cell 2, first side wall 2.1, edge seal 2.2; Thermal insulation pad 3, weak portion 3.1, second main portion 3.2, first channel 4; Thermal management component 5; Buffer member 6; Rubber strip 7; First adhesive 8. DETAILED DESCRIPTION

[0028] The following describes optional embodiments of the present invention with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0029] In the description of the present invention, it should be understood that the terms "distance", "width", "thickness", "up", "down", "left", "right", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In the description of the present invention, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly specifying the quantity of the technical features indicated. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0031] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] In order to prevent the spread of thermal runaway in a battery pack, as shown in Figures 1-4, the present invention provides a battery pack, comprising: a case 1, a battery cell 2 and a thermal insulation pad 3, wherein the case 1 includes a bottom plate 1.1 and a support member 1.2 arranged on the bottom plate 1.1; the battery cell 2 is arranged in the case 1, the end of the battery cell 2 is arranged on the support member 1.2, and the first main body of the battery cell 2 includes a first side wall 2.1 facing the bottom plate; the thermal insulation pad 3 is arranged on the first side wall 2.1, and a first channel 4 is provided between the thermal insulation pad 3 and the bottom plate 1.1, and the thermal conductivity of the thermal insulation pad 3 is less than 0.1W / (mK). By arranging a thermal insulation pad 3 on the first side wall 2.1 of the battery cell 2, and the thermal conductivity of the thermal insulation pad 3 is less than 0.1W / (mK), when a battery cell 2 experiences thermal runaway, the thermal runaway high-temperature gas enters the first channel 4. When the thermal runaway high-temperature gas flows in the first channel 4 and contacts the battery cell 2 adjacent to it, it is blocked by the thermal insulation pad 3 from heat transfer, so the temperature of the battery cell 2 adjacent to it will not rise sharply and cause thermal runaway, thereby avoiding the spread of thermal runaway.

[0033] In an optional embodiment of the present invention, the thermal insulation pad 3 has a flame retardancy rating of V0 and a melting point greater than 1000°C. If a battery cell 2 undergoes thermal runaway and spontaneously ignites, the thermal insulation pad 3 can prevent the fire from spreading to adjacent battery cells 2, thereby preventing the entire battery pack from burning.

[0034] In an optional embodiment of the present invention, as shown in Figures 1 and 3, a battery pack includes multiple battery cells 2 arranged along a first direction. The battery cells 2 can be in the form of soft packs, square shells, blade shells, or other types. The battery pack also includes a thermal management component 5 and a buffer 6. The thermal management component 5 is positioned between two adjacent battery cells 2 to improve heat transfer efficiency to the battery cells 2. The largest surface of the battery cell 2 can be bonded to the thermal management component 5 using thermally conductive adhesive. The aforementioned "battery cell-thermal management component-battery cell" arrangement is used as a battery cell group. A buffer 6 is positioned between two adjacent battery cell groups to bond the battery cells 2 and the buffer 6. By providing the buffer 6, a preload is applied to address expansion of the battery cells 2. The battery cells 2, thermal management component 5, and buffer 6 all extend along the second direction of Figure 1. Alternatively, multiple battery cells 2 can be arranged and electrically connected along the second direction. The thermal management component 5 can be a single-piece, long cold plate or a combination of multiple cold plates. Along the third direction of FIG. 1 and FIG. 3 , the thermal management component 5 extends beyond the battery cell 2 , so that when thermal runaway occurs in the battery cell 2 , the thermal management component 5 can provide a guide for the thermal runaway gas.

[0035] In an optional embodiment of the present invention, as shown in FIG4 , a plurality of spaced weak portions 3.1 are provided on the thermal insulation pad 3 along the length of the battery cell 2. A battery cell 2 experiencing thermal runaway can discharge the thermal runaway gas into the first channel 4 through the plurality of weak portions 3.1 on the thermal insulation pad 3. Three to seven weak portions 3.1 may be spaced along the length of a thermal insulation pad 3. The ends of the thermal insulation pad 3 overlap with the support member 1.2, ensuring that the first side wall of the battery cell 2 is completely covered by the thermal insulation pad, thereby preventing the spread of thermal runaway.

[0036] In an optional embodiment of the present invention, the thermal insulation pad 3 includes a second main portion 3.2 and a weak portion 3.1, wherein the thickness of the weak portion 3.1 is smaller than that of the second main portion 3.2. The thickness of the weak portion 3.1 is set to be smaller than that of the second main portion 3.2, so that the thermal runaway gas can break through the weak portion 3.1 and enter the first channel 4.

[0037] In an optional embodiment of the present invention, the thickness H1 of the weak portion 3.1 and the thickness H2 of the second main portion 3.2 of the thermal insulation pad 3 satisfy: 1mm≤H2≤5mm,

[0038] In an optional embodiment of the present invention, as shown in Figure 4, the thermal insulation pad 3 includes a second main portion 3.2 and a weak portion 3.1, wherein the weak portion 3.1 is a through hole. The weak portion 3.1 is configured as a through hole, allowing thermal runaway gases to directly enter the first channel 4 through the through hole. The through hole can be rectangular, circular, triangular, hexagonal, or irregular in shape. When the through hole is rectangular, the length L1 and width L2 of the through hole satisfy the following requirements: 20mm≤L1≤40mm, 0.1mm≤L2≤2mm. The through hole is designed to be an elongated rectangular hole. When a battery cell 2 experiences thermal runaway, high-pressure, high-temperature gases can easily pass through the through hole into the first channel 4. After entering the larger first channel, the thermal runaway gases are diluted, thereby preventing the thermal runaway gases from contacting adjacent battery cells 2 through the through hole. L2 can be 0.1mm, 0.5mm, 1mm, or 2mm, and L1 can be 20mm, 25mm, 30mm, 35mm, or 40mm.

[0039] In an optional embodiment of the present invention, the thermal insulation pad 3 comprises aerogel and an outer film encapsulating the aerogel. The outer film may be made of, for example, PET. Aerogel has excellent thermal and electrical insulation properties and a high melting point. Therefore, it is positioned on the first side wall 2.1 of the battery cell 2 to prevent thermal runaway from spreading to adjacent battery cells 2.

[0040] ​In an optional embodiment of the present invention, as shown in FIG4 , a rubber strip 7 may be provided between the thermal insulation pad 3 and the first side wall 2.1 . The rubber strip 7 may be used to bond the thermal insulation pad 3 to the first side wall 2.1 of the battery cell 2 .

[0041] In an optional embodiment of the present invention, as shown in Figure 3, the battery cell 2 includes an edge seal 2.2. At least two adhesive strips 7 are disposed between the thermal insulation pad 3 and the first side wall 2.1. The adhesive strips 7 are disposed on either side of the edge seal 2.2. The adhesive strips 7 on either side of the edge seal 2.2 bond the thermal insulation pad 3 to the battery cell 2, thus leaving space for the edge seal 2.2. A single thermal insulation pad 3 can cover the first side wall 2.1 beneath two adjacent battery cells 2. A buffer member 6 is disposed between the two battery cells 2. The edge seals 2.2 of the two battery cells 2 are disposed between the two adhesive strips 7. The edge seals 2.2 of the two battery cells 2 are disposed relative to each other, that is, the edge seals 2.2 of the two battery cells 2 are bent toward each other onto the first side wall 2.1 of the battery cell 2. As shown in Figure 2, the "battery cell 2-buffer member 6-battery cell 2" structure covered by the two thermal insulation pads is disposed as a single unit on the support member 1.2. Specifically, the structure can be bonded to the support member 1.2 using a first adhesive 8.

[0042] In an optional embodiment of the present invention, a fireproof layer is provided on the bottom plate 1.1. The fireproof layer comprises a carbon ceramic material and can be sprayed onto the bottom plate 1.1. The thermal runaway gas, upon entering the first channel 4, will contact the bottom plate 1.1. The fireproof layer can prevent the bottom plate 1.1 from being damaged by the high-temperature thermal runaway gas.

[0043] In an optional embodiment of the present invention, an air inlet and a second channel are provided on the support member 1.2; a third channel and a first explosion-proof valve are provided on the side wall of the box body 1; and the air inlet, the second channel, the third channel, and the explosion-proof valve are connected in sequence. After the thermal runaway gas enters the first channel 4, it contacts the support member 1.2, enters the second channel through the air inlet on the support member 1.2, passes through the third channel connected to the second channel, and is finally discharged from the battery pack through the explosion-proof valve. After the thermal runaway gas passes through the above three channels, the temperature can be reduced, preventing the battery pack from being discharged in the form of open flames or excessively high temperatures, thereby avoiding harm to users.

[0044] In an optional embodiment of the present invention, the air inlet is provided on the side of the support member 1.2 facing the bottom plate 1.1. This allows the thermal runaway gas to enter the second channel 4 for exhaust only when the air pressure in the housing 1 reaches a certain level, impacting the bottom plate 1.1 and exposing the air inlet on the support member 1.2 facing the bottom plate 1.1. This avoids the risk of exhaust in non-thermal runaway conditions.

[0045] In an optional embodiment of the present invention, a second explosion-proof valve is provided on the housing 1, and the second explosion-proof valve is connected to the first channel 4. The thermal runaway gas entering the first channel 4 can also be directly discharged out of the battery pack through the second explosion-proof valve on the housing 1.

[0046] The present invention also provides an electrical device, which includes the battery pack of the above-mentioned optional embodiment. By providing the above-mentioned battery pack, the spread of thermal runaway in the electrical device can be avoided. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like, and the spacecraft can include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0047] The technical solutions of the present invention have been described so far in conjunction with the optional embodiments shown in the accompanying drawings. However, those skilled in the art will readily appreciate that the scope of protection of the present invention is clearly not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent modifications or substitutions to the relevant technical features, and the technical solutions resulting from such modifications or substitutions will fall within the scope of protection of the present invention.

Claims

1. A battery pack, comprising: The box body comprises a bottom plate and a support member arranged on the bottom plate; A battery cell is disposed in the box, an end of the battery cell is disposed on the support member, and a first main body of the battery cell includes a first side wall facing the bottom plate; A thermal insulation pad is arranged on the first side wall, and a first channel is provided between the thermal insulation pad and the bottom plate, and the thermal conductivity of the thermal insulation pad is less than 0.1 W / (mK).

2. The battery pack according to claim 1, characterized in that: The flame retardant grade of the thermal insulation pad is V0.

3. The battery pack according to claim 2, characterized in that: The melting point of the thermal insulation pad is greater than 1000°C.

4. The battery pack according to any one of claims 1 to 3, characterized in that: Along the length direction of the battery cell, the thermal insulation pad is provided with a plurality of spaced apart weak parts.

5. The battery pack according to any one of claims 1 to 3, characterized in that: The thermal insulation pad includes a second main body portion and a weak portion, and the thickness of the weak portion is smaller than the thickness of the second main body portion.

6. The battery pack according to claim 5, characterized in that: The thickness H1 of the weak portion and the thickness H2 of the second main portion satisfy: 1mm≤H2≤5mm, <H1≤1mm。 7. The battery pack according to any one of claims 1 to 3, characterized in that: The thermal insulation pad comprises a second main body portion and a weak portion, and the weak portion is a through hole.

8. The battery pack according to claim 7, characterized in that: The through hole may be in a rectangular, circular, triangular, hexagonal or irregular shape.

9. The battery pack according to claim 8, characterized in that: The through hole is rectangular, and the length L1 and width L2 of the through hole satisfy: 20mm≤L1≤40mm, 0.1mm≤L2≤2mm.

10. The battery pack according to any one of claims 1 to 3, characterized in that: The thermal insulation pad comprises an aerogel and an outer envelope wrapping the aerogel, wherein the outer envelope is insulating.

11. The battery pack according to any one of claims 1 to 3, characterized in that: A rubber strip is arranged between the thermal insulation pad and the first side wall.

12. The battery pack according to claim 11, characterized in that: The battery cell comprises a sealed edge, and at least two adhesive strips are arranged between the thermal insulation pad and the first side wall, and the adhesive strips are arranged on both sides of the sealed edge.

13. The battery pack according to any one of claims 1 to 3, characterized in that: A fireproof layer is arranged on the bottom plate, and the fireproof layer comprises carbon ceramic material.

14. The battery pack according to any one of claims 1 to 3, characterized in that: The support member is provided with an air inlet hole and a second channel; A third channel and a first explosion-proof valve are arranged on the side wall of the box; The air inlet, the second channel, the third channel and the explosion-proof valve are connected in sequence.

15. The battery pack according to claim 14, characterized in that: The air inlet hole is arranged on a side of the support member facing the bottom plate.

16. The battery pack according to claim 15, characterized in that: The box body is provided with a second explosion-proof valve, and the second explosion-proof valve is communicated with the first channel.

17. An electrical device comprising the battery pack according to any one of claims 1 to 16.

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