Protection structure, battery cell assembly and battery

Abstract

The invention relates to the technical field of batteries, in particular to a protection structure, a battery cell assembly and a battery, and the protection structure comprises a blue film used for being installed on a battery cell; the fusing layer is arranged on the blue film, and the fusing layer is arranged on the blue film; wherein when the battery cell is short-circuited and heated due to breakage of the blue film, if the temperature of the battery cell is higher than a first temperature, the fusing layer can be fused and flow to cover or fill the breakage position of the blue film, and if the temperature of the battery cell is higher than a second temperature, the fusing layer covering or filling the breakage position of the blue film can be carbonized to form a blocking part; the first temperature is lower than the second temperature, and the second temperature is lower than the first temperature. According to the battery, the fusing layer is arranged on the blue film, and when the blue film is damaged, a blocking part can be formed at the damaged part of the blue film to block short circuit of the battery cell, so that safety accidents such as fire and explosion caused by continuous short circuit and temperature rise of the battery cell are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a protection structure, a battery cell assembly and a battery. BACKGROUND

[0002] The insulation performance of the battery cell blue film is crucial to the safety of the battery. As a key insulating material inside the battery, the battery cell blue film can provide effective isolation between the battery cells and the external structure, preventing short circuit phenomena caused by direct contact. This helps to prevent safety accidents such as battery overheating, fire or explosion, and ensures the safe operation of the battery under various working conditions. However, during the use of the battery, the blue film may still have a breakage problem. When the blue film is broken, the metal shell of the battery cell will be directly exposed, causing a short circuit and possibly causing a continuous short circuit and fire. SUMMARY

[0003] The embodiments of the present application provide a protection structure having a fuse layer and a blue film. When the blue film is broken, the fuse layer can be carbonized at the broken part to at least partially solve the above technical problems.

[0004] To achieve the above purpose, according to the first aspect of the present application, a protection structure is provided, comprising:

[0005] a blue film for mounting on a battery cell; and

[0006] a fuse layer provided on the blue film;

[0007] When the blue film is broken and the battery cell short circuit is heated, if the battery cell temperature is greater than a first temperature, the fuse layer can melt and flow to cover or fill the broken part of the blue film, and if the battery cell temperature is greater than a second temperature, the fuse layer covering or filling the broken part of the blue film can be carbonized to form a blocking part and block the battery cell short circuit, and the first temperature is less than the second temperature.

[0008] Optionally, the area of the fuse layer is not less than 60% of the area of the blue film; the area of the fuse layer is set so that the fuse layer can cover most of the blue film, and when the blue film is used on the battery cell, the safety performance of the battery cell can be more effectively improved; and / or

[0009] The average thickness of the fuse layer is between 0.01mm and 0.3mm; for the fuse layer, the average thickness is between 0.01mm and 0.3mm, which can meet the use requirements in terms of response speed and reliability when facing the blue film breakage, and the cost is the most superior; and / or

[0010] The resistivity of the blocking part is between 10^12 Ω / cm and 10^15 Ω / cm; the blocking part covering or filling the damaged part of the blue film has a resistivity between 10^12 Ω / cm and 10^15 Ω / cm, which can ensure that the blocking part plays an insulating role at the damaged part of the blue film to block the short circuit of the battery cell.

[0011] Optionally, the area of the fuse layer is not less than 100% of the area of the blue film.

[0012] The fuse layer covers the blue film comprehensively, so that when any position of the blue film is damaged, the fuse layer can quickly melt and flow to cover or fill the damaged part, thereby improving the speed of the fuse layer covering or filling the damaged part of the blue film.

[0013] Optionally, the average thickness of the fuse layer is any one of 0.01 mm, 0.03 mm, 0.1 mm, 0.2 mm, and 0.3 mm.

[0014] When the average thickness of the fuse layer is any one of 0.01 mm, 0.03 mm, 0.1 mm, 0.2 mm, and 0.3 mm, the fuse layer can quickly respond when the blue film is damaged, and finally ensure that a blocking part is formed at the damaged part of the blue film to block the short circuit of the battery cell; and the material cost of the average thickness and the labor cost during spraying are relatively low.

[0015] Optionally, the resistivity of the blocking part is any one of 10^12 Ω / cm, 10^13 Ω / cm, 10^14 Ω / cm, and 10^15 Ω / cm.

[0016] When the resistivity of the blocking part is any one of 10^12 Ω / cm, 10^13 Ω / cm, 10^14 Ω / cm, and 10^15 Ω / cm, the blocking part can play an insulating role at the damaged part of the blue film to block the short circuit of the battery cell.

[0017] Optionally, the first temperature is between 160°C and 280°C; when the blue film is broken instantaneously, the temperature of the battery cell will be greater than 200°C and continue to rise, and the first temperature between 160°C and 280°C can make the fuse layer melt and flow to cover or fill the damaged part of the blue film at the temperature of the battery cell at the moment when the blue film is broken or at the initial stage of the blue film being damaged, so that the fuse layer reacts more timely when the blue film is damaged; and / or,

[0018] The second temperature is between 200°C and 400°C; the second temperature between 200°C and 400°C can ensure that the fuse layer carbonizes to form the fuse layer covering or filling the damaged part of the blue film after melting and flowing to cover or fill the damaged part of the blue film, and before the battery cell is on fire due to the excessively high temperature.

[0019] Optionally, the first temperature is any one of 160℃, 240℃ and 280℃.

[0020] When the first temperature is 160℃, the fuse layer can melt and flow to cover or fill the broken part of the blue film at the moment of the blue film breaking; when the first temperature is 240℃ or 280℃, the fuse layer can melt and flow to cover or fill the broken part of the blue film at the initial stage of the blue film breaking.

[0021] Optionally, the second temperature is any one of 250℃, 300℃, 350℃ and 400℃.

[0022] When the second temperature is any one of 250℃, 300℃, 350℃ and 400℃, the fuse layer can carbonize to form a fuse layer covering or filling the broken part of the blue film after melting and flowing to cover or fill the broken part of the blue film and before the battery catches fire due to the battery temperature being too high.

[0023] Optionally, the fuse layer is arranged on the side of the blue film away from the battery; when the blue film breaks, the fuse layer can form a blocking part between the external structure causing short circuit with the battery and the blue film to cover or fill the broken part of the blue film.

[0024] Optionally, the fuse layer is arranged on the other side of the blue film facing the battery; when the blue film breaks, the fuse layer can form a blocking part between the battery and the blue film to cover or fill the broken part of the blue film.

[0025] Optionally, the fuse layer is arranged on the side of the blue film away from the battery and on the other side of the blue film facing the battery; when the blue film breaks, the fuse layer on the side of the blue film away from the battery can form a blocking part between the external structure causing short circuit with the battery and the blue film, and the fuse layer on the other side of the blue film facing the battery can form another blocking part between the battery and the blue film, so as to cover or fill the broken part of the blue film on both sides of the broken part of the blue film through the two blocking parts.

[0026] Optionally, the fuse layer comprises:

[0027] a filler capable of melting when the temperature of the battery is greater than the first temperature; and

[0028] a matrix capable of swelling and carbonizing when the temperature of the battery is greater than the second temperature, and the filler is arranged in the matrix.

[0029] When the blue film is damaged, causing the battery cell to short-circuit and heat up, if the battery cell temperature is greater than a first temperature, at least a portion of the filler can melt to drive at least a portion of the matrix to flow and cover or fill the damaged area of ​​the blue film. If the battery cell temperature is greater than a second temperature, the matrix covering or filling the damaged area of ​​the blue film can expand to fix itself to the damaged area of ​​the blue film and carbonize to form a blocking part to block the short circuit of the battery cell.

[0030] When the blue film is damaged, the cell will experience a short circuit, causing the temperature to rise. When the cell temperature rises above a first temperature, the filler can melt and flow, simultaneously driving the matrix to flow and cover or fill the damaged area of ​​the blue film. When the cell temperature continues to rise above a second temperature, the matrix covering or filling the damaged area of ​​the blue film can expand to fix itself to the damaged area and carbonize to form a blocking part covering or filling the damaged area of ​​the blue film, thereby blocking the short circuit of the cell.

[0031] Optionally, the filler comprises metal powder with a melting point lower than the first temperature, and the metal powder is dispersed in the matrix so that when the cell temperature is higher than the first temperature, the metal powder can melt and drive the matrix to flow.

[0032] Optionally, the metal powder includes one or more of bismuth powder, bismuth alloy powder, tin powder, tin alloy powder, indium powder, and indium alloy powder. These metal powders or alloy powders have relatively low melting points and can melt and flow when the cell temperature is higher than the first temperature.

[0033] Optionally, the matrix includes a polymer. When the cell temperature is higher than the second temperature, the polymer covering or filling the damaged area of ​​the blue film can expand to form a porous structure. The porous structure can disperse the liquid metal formed by the melting of the metal powder and can be carbonized to form the blocking part.

[0034] After the polymer expands and carbonizes, the resulting blocking part has a porous structure. It can disperse the liquid metal formed by the melting of metal powder through multiple pores, thus preventing the liquid metal or the solidified liquid metal from forming a conductive path at the blocking part, thereby preventing the battery cell from continuing to short-circuit with the external structure.

[0035] Optionally, the polymer includes one or more of modified acrylic resin and polyvinyl butyral. Both modified acrylic resin and polyvinyl butyral are capable of undergoing expansion carbonization at the second temperature to form a blocking portion at the site of blue film damage.

[0036] Optionally, the ratio of the mass of the filler to the mass of the fused layer is between 50% and 75%, so that when the cell temperature is higher than the first temperature, the filler can melt and drive the matrix to flow, and when the cell temperature is higher than the second temperature, the matrix covering or filling the blue film damage area can expand to fix the blue film damage area and carbonize to form a blocking part covering or filling the blue film damage area to block the cell short circuit.

[0037] Optionally, the ratio of the mass of the filler to the mass of the fusion layer is any one of 50%, 60%, and 75%.

[0038] When the mass ratio between the filler and the fused layer is any one of 50%, 60%, and 75%, the filler can melt and drive the matrix to flow when the cell temperature is higher than the first temperature. When the cell temperature is higher than the second temperature, the matrix covering or filling the blue film damage area can expand to fix the blue film damage area and carbonize to form a blocking part covering or filling the blue film damage area to block the cell short circuit.

[0039] According to a second aspect of this application, a battery cell assembly is also provided, comprising:

[0040] The protective structure described in the first aspect; and,

[0041] The battery cell, wherein the protective structure is disposed on the side of the battery cell.

[0042] The battery cell assembly has all the beneficial effects of the protective structure described in the first aspect.

[0043] According to a third aspect of this application, a battery is also provided, comprising the protective structure described in the first aspect and a battery cell, wherein the protective structure is disposed on the side of the battery cell; or,

[0044] It includes multiple protection structures as described in the first aspect and multiple battery cells, wherein the multiple battery cells are connected sequentially or in parallel, and the multiple protection structures are respectively disposed on the sides of the multiple battery cells.

[0045] The battery has all the beneficial effects of the protective structure described in the first aspect.

[0046] In the protection structure of this application embodiment, a fusible layer is provided on the blue film. When the blue film is damaged, the battery cell will experience a temperature rise due to a short circuit. When the battery cell temperature rises above a first temperature, the fusible layer can melt and flow to cover or fill the damaged area of ​​the blue film. When the battery cell temperature continues to rise above a second temperature, the fusible layer covering or filling the damaged area of ​​the blue film can carbonize to form a blocking part and block the short circuit of the battery cell. Thus, when the blue film is damaged, safety accidents such as fire and explosion caused by the continuous short circuit and temperature rise of the battery cell can be avoided. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0049] Figure 1 This is a schematic diagram of the structure of the battery cell assembly provided in an exemplary embodiment of this disclosure.

[0050] Figure 2 This is a cross-sectional view of the protective structure of the battery cell assembly before it was damaged.

[0051] Figure 3 This is a cross-sectional view of the protective structure of the battery cell assembly after it has been damaged.

[0052] Figure 4 This is a cross-sectional view of the first embodiment of the battery cell assembly.

[0053] Figure 5 This is a schematic diagram of the protective structure of the battery cell assembly.

[0054] Figure 6 This is a cross-sectional view of a second embodiment of the battery cell assembly.

[0055] Figure 7 This is a cross-sectional view of the fuse layer of the battery cell assembly.

[0056] Figure 8 yes Figure 7 A magnified view of part A.

[0057] Explanation of reference numerals in the attached figures:

[0058] 1. Protective structure; 11. Blue film; 12. Fuse layer; 121. Blocking part; 122. Frame-shaped part; 123. Filler; 124. Matrix;

[0059] 2. Battery cells. Detailed Implementation

[0060] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0061] The battery cell is the core component of a battery, consisting of positive and negative electrodes, an electrolyte, and a separator, responsible for storing and releasing electrical energy. The performance of the battery cell directly affects the battery's capacity, voltage, cycle life, and safety. To insulate the cell surface, related technologies apply a blue film to it. This blue film effectively isolates the cell from external structures (which can be another battery cell or other structures), preventing short circuits caused by direct contact. This, in turn, prevents safety accidents such as fires or explosions, ensuring the safe operation of the cell under various conditions. The blue film is primarily made of polymer materials such as polyethylene terephthalate (PET).

[0062] However, when the blue film is damaged, it will cause a short circuit between the battery cell and the external structure. Therefore, this application proposes a protective structure that integrates a blue film and a fuse layer. In the initial stage of a short circuit between the battery cell and the external structure caused by the damage of the blue film, the fuse layer can quickly cover or fill the damaged area of ​​the blue film, thereby blocking the connection between the battery cell and the external structure and preventing the battery cell from burning or exploding due to continuous heating caused by the short circuit.

[0063] According to the first aspect of this application, in conjunction with Figures 1-3 It is known that a protective structure 1 is provided, which includes a blue film 11 and a fuse layer 12. The blue film 11 is used to install on the battery cell 2, and the fuse layer 12 is disposed on the blue film 11.

[0064] When the blue film 11 is damaged, causing the battery cell 2 to short-circuit and heat up, if the temperature of the battery cell 2 is greater than the first temperature, the fusible layer 12 can melt and flow to cover or fill the damaged area of ​​the blue film 11. If the temperature of the battery cell 2 is greater than the second temperature, the fusible layer 12 covering or filling the damaged area of ​​the blue film 11 can carbonize to form a blocking part 121 and block the short circuit of the battery cell 2. The first temperature is less than the second temperature.

[0065] It is worth noting that when the ambient temperature changes (the temperature of the battery cell 2 changes), the temperature of the fuse layer 12 will change synchronously with the ambient temperature. Based on its own characteristics, the fuse layer 12 can melt and flow when the temperature is higher than the first temperature, and can carbonize to form the blocking part 121 when the temperature is higher than the second temperature.

[0066] By providing a fusible layer 12 on the blue film 11, when the blue film 11 is damaged, the battery cell 2 will experience a temperature rise due to a short circuit. When the temperature of the battery cell 2 rises above a first temperature, the fusible layer 12 can melt and flow to cover or fill the damaged area of ​​the blue film 11. When the temperature of the battery cell 2 continues to rise above a second temperature, the fusible layer 12 covering or filling the damaged area of ​​the blue film 11 can carbonize to form a blocking part 121, thus blocking the short circuit of the battery cell 2. In this way, when the blue film 11 is damaged, safety accidents such as fire and explosion caused by the continuous short circuit and temperature rise of the battery cell 2 can be avoided.

[0067] For example, the fusing layer 12 is coated onto the blue film 11 by spraying. Specifically, high-pressure spraying can be used, where high pressure is applied to the coating material forming the fusing layer 12, causing it to be atomized and sprayed through a nozzle. The blue film 11 with the fusing layer 12 sprayed onto it is then placed in a temperature-controlled oven for drying. The oven temperature can be set between 50°C and 100°C, with an optimal range of 70°C to 85°C, such as any one of 70°C, 75°C, 80°C, and 85°C.

[0068] In some embodiments, the area of ​​the fuse layer 12 is not less than 60% of the area of ​​the blue film 11; the area of ​​the fuse layer 12 is configured such that it can cover most of the blue film 11, which, when the blue film 11 is used on the battery cell 2, can more effectively improve the safety performance of the battery cell 2; and / or,

[0069] The average thickness of the fuse layer 12 is between 0.01mm and 0.3mm; for the fuse layer 12, an average thickness between 0.01mm and 0.3mm, while meeting the requirements for response speed and reliability when the blue film 11 breaks, the cost is relatively low; and / or,

[0070] The resistivity of the blocking part 121 is between 10^12 Ω / cm and 10^15 Ω / cm; the blocking part 121 covering or filling the damaged part of the blue film 11 is between 10^12 Ω / cm and 10^15 Ω / cm, which can ensure that it plays an insulating role at the damaged part of the blue film 11 to block the short circuit of the cell 2.

[0071] For the area of ​​the fuse layer 12 not less than 60% of the area of ​​the blue film 11, for example, combined with Figure 4It is known that the battery cell 2 used to install the blue film 11 is a square battery cell 2, which includes at least four sides: front, back, left, and right. The front and back sides are each large surface occupying at least 30% of the total surface area of ​​the battery cell 2, or the left and right sides are each large surface occupying at least 30% of the total surface area of ​​the battery cell 2. During the manufacturing, transportation, and use of the battery cell 2, damage to the blue film 11 generally occurs at the corresponding large surfaces of the battery cell 2. Therefore, by ensuring that the area of ​​the fusible layer 12 is not less than 60% of the area of ​​the blue film 11, the blue film 11 coated with the fusible layer 12 can cover at least two large surfaces of the battery cell 2, thereby more effectively improving the safety performance of the battery cell 2; or...

[0072] Combination Figure 5 It is understood that the fusing layer 12, which covers an area of ​​not less than 60% of the blue film 11, may include multiple frame-shaped portions 122 with gradually decreasing dimensions. These frame-shaped portions 122 are sequentially arranged, with the outermost frame-shaped portion 122 surrounding the outer periphery of the side of the blue film 11. When the blue film 11 is damaged at a location corresponding to a frame-shaped portion 122, the frame-shaped portion 122 of the fusing layer 12 can quickly melt and flow to cover or fill the damaged area of ​​the blue film 11, ultimately forming a blocking portion 121 covering or filling the damaged area. When the gap between the frame-shaped portions 122 of the blue film 11 is damaged, the frame-shaped portion 122 near the gap can also quickly melt and flow to cover or fill the damaged area of ​​the blue film 11, ultimately forming a blocking portion 121 covering or filling the damaged area, thereby more effectively improving the safety performance of the battery cell 2.

[0073] In some embodiments, combined with Figure 6 It can be seen that the area of ​​the fuse layer 12 is not less than 100% of the area of ​​the blue film 11.

[0074] The fusing layer 12 completely covers the blue film 11, so that when any part of the blue film 11 is damaged, the fusing layer 12 can quickly melt and flow to cover or fill the damaged area, thereby increasing the speed at which the fusing layer 12 covers or fills the damaged area of ​​the blue film 11.

[0075] In some embodiments, the average thickness of the fusible layer 12 can be any one of 0.01 mm, 0.03 mm, 0.1 mm, 0.2 mm, and 0.3 mm.

[0076] When the average thickness of the fuse layer 12 is any one of 0.01mm, 0.03mm, 0.1mm, 0.2mm, and 0.3mm, the fuse layer 12 can respond quickly when the blue film 11 is damaged, and ultimately ensure that a blocking part 121 is formed at the point of damage to the blue film 11 to prevent short circuit of the battery cell 2; moreover, the material cost and labor cost of these average thicknesses are relatively low. It is understood that the average thickness of the fuse layer 12 can also be other values, and this embodiment does not limit this.

[0077] In some embodiments, the resistivity of the blocking portion 121 is any one of 10^12 Ω / cm, 10^13 Ω / cm, 10^14 Ω / cm and 10^15 Ω / cm.

[0078] When the resistivity of the blocking part 121 is any one of 10^12 Ω / cm, 10^13 Ω / cm, 10^14 Ω / cm, and 10^15 Ω / cm, it can provide insulation at the point of damage to the blue film 11, thereby preventing a short circuit in the battery cell 2. It is understood that the resistivity of the blocking part 121 can also be other values, and this embodiment does not impose any limitations on this.

[0079] In some embodiments, the first temperature is between 160°C and 280°C; when the blue film 11 ruptures, the cell 2 short-circuit and heats up, causing the temperature to exceed 200°C and continue to rise. The first temperature being between 160°C and 280°C allows the fusion layer 12 to melt and flow at the temperature of the cell 2 at the moment the blue film 11 ruptures or in the early stages of damage, covering or filling the damaged area of ​​the blue film 11, thus enabling a more timely reaction when the blue film 11 ruptures; and / or,

[0080] The second temperature is between 200°C and 400°C; the second temperature is between 200°C and 400°C, which can ensure that the fuse layer 12 is carbonized to form the fuse layer 12 covering or filling the damaged area of ​​the blue film 11 after melting and flowing to cover or fill the damaged area of ​​the blue film 11, and before the cell 2 catches fire due to excessive temperature.

[0081] In some embodiments, the first temperature is any one of 160°C, 240°C, and 280°C.

[0082] Specifically, when the first temperature is 160°C, at the instant the blue film 11 ruptures, the fusible layer 12 can melt and flow at the temperature of the battery cell 2 to cover or fill the damaged area of ​​the blue film 11; when the first temperature is 240°C or 280°C, at the initial stage of the blue film 11 rupture, the fusible layer 12 can melt and flow at the temperature of the battery cell 2 to cover or fill the damaged area of ​​the blue film 11. It is understood that the first temperature can also be other values, and this embodiment does not limit it.

[0083] In some embodiments, the second temperature is any one of 250°C, 300°C, 350°C, and 400°C.

[0084] When the second temperature is any one of 250°C, 300°C, 350°C, and 400°C, it can satisfy the requirement that the fusible layer 12, after melting and flowing to cover or fill the damaged area of ​​the blue film 11, and before ignition caused by excessive temperature of the battery cell 2, carbonizes to form the fusible layer 12 covering or filling the damaged area of ​​the blue film 11. It is understood that the second temperature can also be other values, and this embodiment does not limit it.

[0085] In some embodiments, the fusible layer 12 is disposed on the side of the blue film 11 away from the cell 2; when the blue film 11 is damaged, the fusible layer 12 can form a blocking part 121 between the external structure that is short-circuited with the cell 2 and the blue film 11 to cover or fill the damaged part of the blue film 11.

[0086] In some embodiments, the fusible layer 12 is disposed on the other side of the blue film 11 facing the cell 2; when the blue film 11 is damaged, the fusible layer 12 can form a blocking portion 121 between the cell 2 and the blue film 11 to cover or fill the damaged area of ​​the blue film 11.

[0087] In some embodiments, a fusible layer 12 is provided on both the side of the blue film 11 facing away from the battery cell 2 and the side facing the battery cell 2. When the blue film 11 is damaged, the fusible layer 12 on the side of the blue film 11 facing away from the battery cell 2 can form a blocking part 121 between the external structure that is short-circuited with the battery cell 2 and the blue film 11. The fusible layer 12 on the other side of the blue film 11 facing the battery cell 2 can form another blocking part 121 between the battery cell 2 and the blue film 11. The blocking part 121 and the other blocking part 121 are respectively on both sides of the damaged area of ​​the blue film 11 to cover or fill the damaged area of ​​the blue film 11.

[0088] In some embodiments, combined with Figures 7-8 It is known that the fusible layer 12 includes a filler 123 and a substrate 124. The filler 123 can melt when the temperature of the cell 2 is higher than the first temperature, and the substrate 124 can expand and carbonize when the temperature of the cell 2 is higher than the second temperature. The filler 123 is disposed on the substrate 124.

[0089] When the blue film 11 is damaged, causing the battery cell 2 to short-circuit and heat up, if the temperature of the battery cell 2 is greater than the first temperature, at least part of the filler 123 can melt to drive at least part of the substrate 124 to flow and cover or fill the damaged area of ​​the blue film 11. If the temperature of the battery cell 2 is greater than the second temperature, the substrate 124 covering or filling the damaged area of ​​the blue film 11 can expand to fix itself to the damaged area of ​​the blue film 11 and carbonize to form a blocking part 121 to block the short circuit of the battery cell 2.

[0090] When the blue film 11 is damaged, the temperature of the cell 2 will rise due to a short circuit. When the temperature of the cell 2 rises above the first temperature, the filler 123 can melt and flow, and at the same time drive the substrate 124 to flow, so as to cover or fill the damaged area of ​​the blue film 11. When the temperature of the cell 2 continues to rise above the second temperature, the substrate 124 covering or filling the damaged area of ​​the blue film 11 can expand to fix itself to the damaged area of ​​the blue film 11, and carbonize to form a blocking part 121 covering or filling the damaged area of ​​the blue film 11, so as to block the short circuit of the cell 2.

[0091] In some embodiments, the filler 123 includes metal powder with a melting point lower than a first temperature and the metal powder is dispersed in the matrix 124 so that when the temperature of the cell 2 is higher than the first temperature, the metal powder can melt and drive the matrix 124 to flow.

[0092] In some embodiments, the metal powder includes one or more of bismuth powder, bismuth alloy powder, tin powder, tin alloy powder, indium powder, and indium alloy powder. These metal powders or alloy powders have relatively low melting points and can melt and flow when the temperature of the cell 2 is higher than the first temperature.

[0093] In some embodiments, the substrate 124 includes a polymer. When the temperature of the cell 2 is greater than the second temperature, the polymer covering or filling the damaged area of ​​the blue film 11 can expand to form a porous structure. The porous structure can disperse the liquid metal formed by the melting of metal powder and can carbonize to form the blocking portion 121.

[0094] After the polymer expands and carbonizes, the resulting blocking part 121 has a porous structure. It can disperse the liquid metal formed by the melting of metal powder through multiple pores formed by itself, thereby preventing the liquid metal or the metal structure formed after the liquid metal solidifies from conducting between the battery cell 2 and the external structure, and preventing a short circuit between the battery cell 2 and the external structure.

[0095] For example, when the blue film 11 is damaged, after the cell 2 is short-circuited with the external structure, Joule heating is generated through the short-circuit current, so that the temperature of the cell 2 is raised to a temperature greater than the first temperature. At this time, the filler 123 melts rapidly at an ambient temperature higher than the first temperature, and drives the substrate 124 to flow to the damaged area of ​​the blue film 11 to fill or cover it. The temperature of the cell 2 continues to rise, from a temperature greater than the first temperature to a temperature greater than the second temperature. At this time, the organic components of the substrate 124 rapidly vaporize, generating gas that escapes, causing the substrate 124 to expand to form a loose porous structure fixed at the damaged area of ​​the blue film 11, and finally carbonizes to form a blocking part 121. Specifically, the blocking part 121 is a porous, loose solid carbonaceous residue.

[0096] In some embodiments, the polymer includes one or more of modified acrylic resin and polyvinyl butyral. Both modified acrylic resin and polyvinyl butyral are capable of expanding and carbonizing at the second temperature to form a blocking portion 121 at the site of damage to the blue film 11.

[0097] In some embodiments, the mass ratio of the filler 123 to the mass of the fused layer 12 is between 50% and 75%, so that when the temperature of the cell 2 is higher than the first temperature, the filler 123 can melt and drive the substrate 124 to flow, and when the temperature of the cell 2 is higher than the second temperature, the substrate 124 covering or filling the damaged area of ​​the blue film 11 can expand to fix the damaged area of ​​the blue film 11 and carbonize to form the blocking part 121 covering or filling the damaged area of ​​the blue film 11 to block the short circuit of the cell 2.

[0098] In some embodiments, the mass ratio of filler 123 to the mass of fusion layer 12 is any one of 50%, 60%, and 75%.

[0099] When the mass ratio between filler 123 and fuse layer 12 is any one of 50%, 60%, and 75%, it ensures that when the temperature of cell 2 is higher than a first temperature, filler 123 can melt and drive the substrate 124 to flow. When the temperature of cell 2 is higher than a second temperature, the substrate 124 covering or filling the damaged area of ​​blue film 11 can expand to fix itself to the damaged area of ​​blue film 11 and carbonize to form a blocking part 121 covering or filling the damaged area of ​​blue film 11, thereby blocking the short circuit of cell 2. It is understood that the mass ratio between filler 123 and fuse layer 12 can also be other values, and this embodiment does not limit this.

[0100] According to a second aspect of this application, this application also provides a battery cell assembly, which includes a protective structure 1 and a battery cell 2 as described in any of the above embodiments, with the protective structure 1 disposed on the side of the battery cell 2. This battery cell 2 assembly has the beneficial effects of the protective structure 1 of any of the above embodiments.

[0101] According to a third aspect of this application, this application also provides a battery, the battery including a protective structure 1 and a cell 2 as described in any of the above embodiments, the protective structure 1 being disposed on the side of the cell 2. Alternatively,

[0102] The battery includes multiple protection structures 1 and multiple battery cells 2 as described in the above embodiments. The multiple battery cells 2 are connected sequentially or in parallel, and the multiple protection structures 1 are respectively disposed on the sides of the multiple battery cells 2.

[0103] The battery has the beneficial effects of the protection structure 1 of any of the above embodiments.

[0104] In the protection structure 1 of this application embodiment, by providing a fusible layer 12 on the blue film 11, when the blue film 11 is damaged, the battery cell 2 will cause the temperature to rise due to a short circuit. When the temperature of the battery cell 2 rises above a first temperature, the fusible layer 12 can melt and flow to cover or fill the damaged area of ​​the blue film 11. When the temperature of the battery cell 2 continues to rise above a second temperature, the fusible layer 12 covering or filling the damaged area of ​​the blue film 11 can carbonize to form a blocking part 121 and block the short circuit of the battery cell 2. Thus, when the blue film 11 is damaged, safety accidents such as fire and explosion caused by the continuous short circuit and temperature rise of the battery cell 2 can be avoided.

[0105] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0106] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0107] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0108] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A protective structure, characterized in that, include: Blue film, used for installation on battery cells; and, A fusible layer is disposed on the blue film; When the blue film is damaged, causing the battery cell to short-circuit and heat up, if the battery cell temperature is greater than a first temperature, the fusible layer can melt and flow to cover or fill the damaged area of ​​the blue film. If the battery cell temperature is greater than a second temperature, the fusible layer covering or filling the damaged area of ​​the blue film can carbonize to form a blocking part and block the battery cell short circuit. The first temperature is less than the second temperature.

2. The protective structure according to claim 1, characterized in that, The area of ​​the fusible layer is not less than 60% of the area of ​​the blue film; and / or, The average thickness of the fusible layer is between 0.01 mm and 0.3 mm; and / or, The resistivity of the blocking part is between 10^12 Ω / cm and 10^15 Ω / cm.

3. The protective structure according to claim 1, characterized in that, The first temperature is between 160°C and 280°C; and / or, The second temperature is between 200℃ and 400℃.

4. The protective structure according to any one of claims 1-3, characterized in that, The fusible layer is disposed on the side of the blue film facing away from the battery cell; and / or, The fusible layer is located on the side of the blue film facing the battery cell.

5. The protective structure according to any one of claims 1-3, characterized in that, The fuse layer includes: The filler is capable of melting when the cell temperature is above a first temperature; and, The matrix is ​​capable of expanding and carbonizing when the cell temperature is higher than a second temperature, and the filler is disposed in the matrix; When the blue film is damaged, causing the battery cell to short-circuit and heat up, if the battery cell temperature is greater than a first temperature, at least a portion of the filler can melt to drive at least a portion of the matrix to flow and cover or fill the damaged area of ​​the blue film. If the battery cell temperature is greater than a second temperature, the matrix covering or filling the damaged area of ​​the blue film can expand to fix itself to the damaged area of ​​the blue film and carbonize to form a blocking part to block the short circuit of the battery cell.

6. The protective structure according to claim 5, characterized in that, The filler comprises metal powder, the melting point of which is lower than the first temperature, and the metal powder is dispersed in the matrix.

7. The protective structure according to claim 6, characterized in that, The metal powder includes one or more of bismuth powder, bismuth alloy powder, tin powder, tin alloy powder, indium powder, and indium alloy powder.

8. The protective structure according to claim 6, characterized in that, The matrix includes a polymer. When the cell temperature is higher than the second temperature, the polymer covering or filling the damaged area of ​​the blue film can expand to form a porous structure. The porous structure can disperse the liquid metal formed by the melting of the metal powder and can carbonize to form the blocking part.

9. The protective structure according to claim 8, characterized in that, The polymer includes one or more of modified acrylic resin and polyvinyl butyral.

10. The protective structure according to claim 7, characterized in that, The ratio of the mass of the filler to the mass of the fusion layer is between 50% and 75%.

11. A battery cell assembly, characterized in that, include: The protective structure as described in any one of claims 1-10; and, The battery cell, wherein the protective structure is disposed on the side of the battery cell.

12. A battery, characterized in that, Includes the protective structure and battery cell as described in any one of claims 1-10, wherein the protective structure is disposed on the side of the battery cell; or, It includes a plurality of protective structures as described in any one of claims 1-10 and a plurality of battery cells, wherein the plurality of battery cells are connected sequentially or in parallel, and the plurality of protective structures are respectively disposed on the sides of the plurality of battery cells.

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