Battery cell

Abstract

The invention provides a battery cell, and relates to the technical field of battery cells. The battery cell comprises an electrode assembly and a shell, the electrode assembly is arranged in the shell, and an explosion-proof structure is arranged on the shell; the valve opening area S of the explosion-proof structure, the valve opening pressure P of the explosion-proof structure, the liquid injection amount m of the electrolyte of the battery cell and the capacity C of the battery cell meet the following formula: S * P-C / (m * 1000) is more than or equal to 2.4 and less than or equal to 5.4. By reasonably setting the valve opening area and the valve opening pressure of the anti-explosion structure, the electrolyte injection amount of the battery cell and the capacity of the battery cell, the anti-explosion structure can be opened in time when the battery cell breaks down to cause thermal runaway, and different parameters can be set according to actual conditions such as the capacity of the battery cell, so that the thermal runaway of the battery cell is avoided. Therefore, the explosion-proof requirement of the high-capacity battery cell is met.

Description

Technical Field

[0001] The present application relates to the technical field of battery cells, and in particular to a battery cell. Background Art

[0002] In the related art, power cells usually use an aluminum shell structure and an explosion-proof structure is set on the aluminum shell. The explosion-proof structure opens when the cell thermally runs away, and plays the role of exhausting and relieving pressure to prevent the cell from exploding due to excessive internal air pressure. However, as the capacity increases, the explosion-proof structure in the related art gradually fails to meet the explosion-proof requirements. Specifically, the explosion-proof structure may not be opened in time after thermal runaway occurs, resulting in the risk of explosion of the cell. Summary of the invention

[0003] The embodiments of the present application provide a battery cell, which is used to improve the technical problem that an explosion-proof structure may not be able to be opened in time after the battery cell has thermal runaway.

[0004] In a first aspect, an embodiment of the present application provides a battery cell, comprising an electrode assembly and a shell, wherein the electrode assembly is disposed in the shell, and an explosion-proof structure is disposed on the shell;

[0005] The valve opening area S of the explosion-proof structure, the valve opening pressure P of the explosion-proof structure, the electrolyte injection volume m of the battery cell, and the capacity C of the battery cell satisfy the following formula:

[0006] 2.4≤S×P-C / (m×1000)≤5.4.

[0007] In some embodiments of the present application, the explosion-proof structure is provided with a notch, and the depth of the notch and the valve opening area of ​​the explosion-proof structure satisfy the following relationship:

[0008] 0.05≤d / S≤0.2;

[0009] The length of the notch and the valve opening pressure of the explosion-proof structure satisfy the following relationship:

[0010] L = β × 1 / P + γ;

[0011] The width of the notch is inversely proportional to the valve opening area of ​​the explosion-proof structure;

[0012] Wherein, d is the depth of the notch, S is the valve opening area of ​​the explosion-proof structure, L is the length of the notch, P is the valve opening pressure of the explosion-proof structure, and β and γ are both constants.

[0013] In some embodiments of the present application, the total area of ​​the notches and the valve opening area satisfy the following relationship:

[0014] S k =ζS;

[0015] Among them, S k is the total area of ​​the notch, ζ is a constant, and the value range of ζ is 0.1-0.3.

[0016] In some embodiments of the present application, the valve opening area of ​​the explosion-proof structure satisfies the following relationship:

[0017] S = αm + δ1;

[0018] Wherein, α and δ1 are constants, and the value range of α is 1.2-1.8, and the value range of δ1 is 0.8-1.8.

[0019] In some embodiments of the present application, the value range of α is 1.4-1.6, and the value range of δ1 is 1.2-1.5.

[0020] In some embodiments of the present application, the electrolyte injection amount of the battery cell and the capacity of the battery cell satisfy the following relationship:

[0021] m = kC / 1000;

[0022] Wherein, k is a constant, and the value range of k is 2.5-4.

[0023] In some embodiments of the present application, the value range of the valve opening area S of the explosion-proof structure is 0.5-10 cm 2 ; The value range of the valve opening pressure P of the explosion-proof structure is 0.5-1MPa; the value range of the electrolyte injection volume m of the battery cell is 0.25-3.2kg; the value range of the capacity C of the battery cell is 100-800Ah.

[0024] In some embodiments of the present application, the value range of the valve opening area S of the explosion-proof structure is 2.5-5.0 cm 2 .

[0025] In some embodiments of the present application, the battery cell includes a cover plate, on which the explosion-proof structure is provided and an explosion-proof hole is opened, and the explosion-proof hole is connected to the shell; the explosion-proof structure is provided on the cover plate and covers the explosion-proof hole.

[0026] In some embodiments of the present application, the active material of the battery cell is any one of an iron-lithium system, a medium-nickel ternary system, a high-nickel ternary system, a sodium-electric system, and a manganese iron phosphate lithium system.

[0027] Beneficial effects of the embodiments of the present application:

[0028] The present application provides a battery cell, and the cover plate reasonably sets the valve opening area, valve opening pressure, electrolyte injection amount of the battery cell and the capacity of the battery cell of the explosion-proof structure, so that when the battery cell fails and causes thermal runaway, the explosion-proof structure can be opened in time, and different parameters can be set according to actual conditions, such as the capacity of the battery cell, to meet the explosion-proof requirements of large-capacity batteries. In detail, by using the formula 2.4≤S×P-C / (m×1000)≤5.4, the four parameters of the valve opening area, valve opening pressure, electrolyte injection amount of the battery cell and the capacity of the battery cell of the explosion-proof structure are linked, so that technicians can adjust the parameters according to the actual conditions of the battery cell through the formula to adapt to the explosion-proof requirements of batteries of different capacities. The values ​​of the left and right boundaries of the formula constitute the safety range in which the explosion-proof structure can play an explosion-proof role. Specifically, when the parameters of the explosion-proof structure meet S×P-C / (m×1000)≥2.4, it can ensure that the valve opening area and valve opening pressure of the explosion-proof structure can effectively cope with the sharp rise in the internal pressure of the battery cell. When the parameters of the explosion-proof structure meet S×P-C / (m×1000)≤5.4, it can prevent the opening conditions of the explosion-proof structure from being too harsh, that is, it can prevent the situation where the explosion-proof structure cannot be opened in time during thermal runaway, and ensure that the battery cell will not explode due to excessive pressure when overheated. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0030] Figure 2 It is a structural schematic diagram of a cover plate provided in an embodiment of the present application.

[0031] Description of reference numerals:

[0032] 1. Battery cell; 11. Shell; 12. Cover plate; 121. Plate; 122. Explosion-proof structure; 1221. Notch; 123. Pole. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0034] See also Figure 1 , an embodiment of the present application provides a battery cell 1, comprising a shell 11, an electrode assembly (not shown in the figure) and a cover plate 12. Among them, an opening is provided on one side of the shell 11 to facilitate the assembly of components in the battery cell 1, such as facilitating the placement of the electrode assembly into the shell 11. The electrode assembly is arranged in the shell 11 and connected to the cover plate 12, specifically electrically connected to the pole 123 of the cover plate 12, for conducting the electrical energy of the electrode assembly. The cover plate 12 is provided at the opening of the shell 11, for sealing the opening of the shell 11, so that the cover plate 12 is sealed and connected to the shell 11.

[0035] It should be noted that the active material inside the battery cell 1 can be any one of an iron-lithium system, a medium-nickel ternary system, a high-nickel ternary system, a sodium-electric system, and a manganese iron-phosphate lithium system.

[0036] See also Figure 2 The cover plate 12 includes a plate body 121, a pole 123 and an explosion-proof structure 122. The pole 123 includes a positive pole and a negative pole, which are arranged opposite to each other along the length direction of the plate body 121, and the explosion-proof structure 122 is arranged between the positive pole and the negative pole. The plate body 121 is arranged on the shell 11 and seals and covers the opening of the shell 11. An explosion-proof hole is also opened on the plate body 121. Correspondingly, the explosion-proof structure 122 is located at the explosion-proof hole and covers the explosion-proof hole. The positive pole and the negative pole are respectively connected to the positive electrode and the negative electrode in the electrode assembly.

[0037] Among them, the valve opening area S of the explosion-proof structure 122, the valve opening pressure P of the explosion-proof structure 122, the injection amount m of the electrolyte of the battery cell 1, and the capacity C of the battery cell 1 satisfy the following formula:

[0038] 2.4≤S×P-C / (m×1000)≤5.4;

[0039] S is the valve opening area of ​​the explosion-proof structure 122, P is the valve opening pressure of the explosion-proof structure 122, m is the injection amount of the electrolyte of the battery cell 1, and C is the capacity of the battery cell 1. It should be noted that the valve opening area of ​​the explosion-proof structure 122 refers to the effective channel area of ​​the pressure relief channel of the explosion-proof structure 122 through which the internal gas passes when the explosion-proof structure 122 is in the open state. The valve opening pressure of the explosion-proof structure 122 refers to the pressure value inside the battery cell when the explosion-proof structure 122 starts to start and forms a pressure relief channel. The injection amount of the electrolyte of the battery cell 1 refers to the total mass of the electrolyte filled inside the battery cell. The capacity of the battery cell 1 refers to the total amount of electricity that the battery cell can provide under specific charging and discharging conditions.

[0040] The technical solution provided in the present application reasonably sets the valve opening area, valve opening pressure, electrolyte injection amount of the battery cell 1 and the capacity of the battery cell 1 of the explosion-proof structure 122, so that when the battery cell 1 fails and causes thermal runaway, the explosion-proof structure 122 can be opened in time, and different parameters can be set according to actual conditions, such as the capacity of the battery cell 1, so as to meet the explosion-proof requirements of large-capacity battery cells 1. In detail, by using the formula 2.4≤S×P-C / (m×1000)≤5.4, the four parameters of the valve opening area, valve opening pressure, electrolyte injection amount of the battery cell 1 and the capacity of the battery cell 1 of the explosion-proof structure 122 are linked, so that technicians can use the formula to adjust the parameters according to the actual conditions of the battery cell 1 to meet the explosion-proof requirements of battery cells 1 of different capacities. The values ​​of the left and right boundaries of the formula constitute the safe range within which the explosion-proof structure 122 can play an explosion-proof role. Specifically, when the parameters of the explosion-proof structure 122 satisfy S×P-C / (m×1000)≥2.4, it can ensure that the valve opening area and valve opening pressure of the explosion-proof structure 122 can effectively cope with the sharp increase in the internal pressure of the battery cell 1. When the parameters of the explosion-proof structure 122 satisfy S×P-C / (m×1000)≤5.4, it can prevent the opening conditions of the explosion-proof structure 122 from being too harsh, that is, it can avoid the situation where the explosion-proof structure 122 cannot be opened in time during thermal runaway, ensuring that the battery cell 1 will not explode due to excessive pressure when overheating.

[0041] Specifically, S in the above formula represents the valve opening area of ​​the explosion-proof structure 122, and the unit of S is cm2, which refers to the area through which gas can pass after the explosion-proof structure 122 is opened. The larger the valve opening area, the faster the pressure is released. P represents the valve opening pressure of the explosion-proof structure 122 (unit: MPa), that is, the pressure value at which the explosion-proof structure 122 starts to open. The higher the valve opening pressure, the stronger the explosion-proof structure 122 is able to tolerate the pressure inside the battery cell 1. m represents the electrolyte injection volume of the battery cell 1 (unit: kg), that is, the total weight of the electrolyte filled in the battery cell 1. The injection volume affects the speed of pressure accumulation in the battery cell 1. The more the injection volume, the faster the internal pressure accumulates. C represents the capacity of the battery cell 1 (unit: Ah), that is, the rated capacity of the battery cell 1, which affects the charge and discharge performance of the battery cell 1. The larger the capacity, the more energy the battery cell 1 can provide, but it is also more likely to generate heat during the charge and discharge process.

[0042] In one embodiment, it is assumed that the parameters of the battery cell 1 are as follows:

[0043] The capacity of the battery cell 1 is C=300Ah; the injection amount of the electrolyte is m=1kg; the valve opening area of ​​the explosion-proof structure 122 is S=3cm2; and the valve opening pressure is P=1MPa.

[0044] Substituting the above specific values ​​into the formula, we can get:

[0045] S×P-C / (m×1000)=_0.33, it can be seen that the calculated value does not satisfy the range of 2.4≤S×PC / (m×1000)≤5.4. Those skilled in the art can selectively adjust the four parameters of the valve opening area of ​​the explosion-proof structure 122, the valve opening pressure of the explosion-proof structure 122, the injection amount of the electrolyte of the battery cell 1, and the capacity of the battery cell 1 according to the calculated values. In the above-mentioned example embodiment, since the calculation result is lower than the lower limit of the formula 2.4, this indicates that the current combination of the valve opening area and the valve opening pressure may not be sufficient to resist the pressure accumulation inside the battery cell 1 in actual use. Therefore, the staff may need to increase the valve opening area or increase the valve opening pressure so that the formula calculation result rises to above 2.4, thereby ensuring the safety of the explosion-proof structure 122. The ratio of the injection amount and the capacity in the formula plays a significant role in the pressure response of the explosion-proof structure 122. In this example, since the injection volume is large (1kg) and the capacity is relatively small (300Ah), the ratio of the injection volume to the capacity is too large, which directly reduces the final calculation result. Therefore, if the injection volume is relatively large, a larger valve opening area or valve opening pressure is required to offset this effect. By using this formula, the staff can ensure the opening reliability of the explosion-proof structure 122 by setting a reasonable valve opening area and pressure range under different capacities and injection volume conditions. In the event that the conditions are not met, the formula provides guidance to the staff, indicating which parameters need to be adjusted to meet safety requirements.

[0046] In some embodiments, the value range of the valve opening area S of the explosion-proof structure 122 is 0.5-10cm2; the value range of the valve opening pressure P of the explosion-proof structure 122 is 0.5-1MPa; the value range of the electrolyte injection volume m of the battery cell 1 is 0.25-3.2kg; the value range of the capacity C of the battery cell 1 is 100-800Ah. The value ranges of the above parameters are obtained through experiments. The staff can set the battery cell 1 according to the value ranges of the above parameters. For example:

[0047] Assume that the design parameters of a certain battery cell 1 are as follows: the capacity of the battery cell 1 C=400Ah; the injection amount of the electrolyte m=1.5kg; the valve opening area of ​​the explosion-proof structure 122 S=6cm2; and the valve opening pressure P=0.8MPa.

[0048] Substituting these parameters into the formula:

[0049] 2.4≤S×P-C / (m×1000)≤5.4, we can get:

[0050] S×P-C / (m×1000)=1.05.

[0051] The calculation result does not satisfy the formula 2.4≤S×P-C / (m×1000)≤5.4, so the staff knows that the battery cell 1 needs to be further adjusted in parameters such as valve opening area, valve opening pressure, injection volume or capacity.

[0052] To satisfy the formula, the staff increases the valve opening pressure to 1 MPa, and the calculated value is 2.25. At this time, the calculation result is within the range of the formula and meets the safety requirements. The staff can select this parameter combination for the specific application of the explosion-proof structure 122.

[0053] Furthermore, the value range of the valve opening area S of the explosion-proof structure 122 can be further limited to 2.5-5.0 cm2. The valve opening area value in this range is suitable for application to specific medium and large capacity batteries 1 (such as 300-600Ah batteries 1) to more accurately balance the requirements between pressure release and the structural strength of the explosion-proof structure 122. By narrowing the value range of the valve opening area, further control of the pressure release effect can be achieved, so that the explosion-proof structure 122 can operate more stably under specific capacity and pressure.

[0054] In some embodiments, a portion of the explosion-proof structure 122 that is aligned with the explosion-proof hole is provided with a notch 1221, and the depth of the notch 1221 and the valve opening area of ​​the explosion-proof structure 122 satisfy the following relationship:

[0055] 0.05≤d / S≤0.2;

[0056] The length of the notch 1221 and the valve opening area of ​​the explosion-proof structure 122 satisfy the following relationship:

[0057] L = β × 1 / P + γ;

[0058] The width of the notch 1221 is inversely proportional to the valve opening area of ​​the explosion-proof structure 122;

[0059] Wherein, d is the depth of the notch 1221, S is the valve opening area of ​​the explosion-proof structure 122, L is the length of the notch 1221, P is the valve opening pressure of the explosion-proof structure 122, and β and γ are both constants.

[0060] In detail, by controlling the depth, length and width of the notch 1221, the explosion-proof structure 122 is preferentially torn along the notch 1221 when the set valve opening pressure is reached, ensuring that the pressure is released in a safe range in a timely manner. The depth of the notch 1221 is proportional to the valve opening area, that is, 0.05≤d / S≤0.2, which means that the depth of the notch 1221 can ensure that there is a preferential tearing point on the surface of the explosion-proof structure 122 under the condition of satisfying the valve opening area. Combined with the inverse relationship between the length of the notch 1221 and the valve opening pressure L=β×1 / P+γ, the length of the notch 1221 increases at a lower pressure, thereby increasing the tearing path and preventing unstable tearing when high pressure accumulates. By utilizing the inverse relationship between the width of the notch 1221 and the valve opening pressure, the width of the notch 1221 is larger at a lower pressure, which is conducive to directional tearing at low pressure and further improves the pressure release effect. When the valve opening pressure is low, the width of the notch 1221 is large, making the notch 1221 area easy to tear, thereby ensuring that the explosion-proof structure 122 will not open for no reason when the pressure is lower than the set pressure. When the valve opening pressure is high, the width of the notch 1221 becomes narrower to ensure the strength of the valve body structure. Under the limitation of the depth, length and width of the notch 1221, the tearing path of the explosion-proof structure 122 will not be out of control under specific pressure conditions, and the total area of ​​the notch 1221 still meets the formula conditions, ensuring the structural stability of the explosion-proof structure 122.

[0061] Furthermore, the total area of ​​the notches 1221 and the valve opening area satisfy the following relationship:

[0062] S k =ζS;

[0063] Among them, S k is the total area of ​​the notch 1221, ζ is a constant, and the value range of ζ is 0.1-0.3.

[0064] By S k =ζS This formula can ensure that the area of ​​the notch 1221 will not be too large to weaken the structural strength of the explosion-proof structure 122, and will not be too small to affect the tearing effect. It should be noted that S k is the total area of ​​the notches 1221, specifically the sum of the surface areas of all the notches 1221 on the explosion-proof structure 122. The total area of ​​the notches 1221 is used to control the tearing area of ​​the explosion-proof structure 122 to avoid structural failure caused by large-area tearing. The proportionality coefficient ζ is used to represent the ratio between the total area of ​​the notches 1221 and the valve opening area to control the size of the area of ​​the notches 1221. When the proportionality coefficient value is large, the total area of ​​the notches 1221 is relatively large; when the proportionality coefficient is small, the area of ​​the notches 1221 is relatively small.

[0065] In some embodiments, the valve opening area of ​​the explosion-proof structure 122 satisfies the following relationship:

[0066] S=αm+δ1, this formula defines that the valve opening area S should be in linear proportion to the injection volume m, so as to ensure that the explosion-proof structure 122 can adaptively adjust the valve opening area according to the injection volume m. Among them, α and δ1 are constants, and the value range of α is 1.2-1.8, and the value range of δ1 is 0.8-1.8.

[0067] The staff can determine the valve opening area of ​​the explosion-proof structure 122 by using the valve opening area formula of the explosion-proof structure 122, and then substitute the determined valve opening area into the formula 2.4≤S×P-C / (m×1000)≤5.4 to check whether the current valve opening area meets the requirements.

[0068] Furthermore, the value range of the adjustment coefficient α may be 1.4-1.6, and the value range of the constant offset δ1 may be 1.2-1.5.

[0069] In some embodiments, the electrolyte injection amount of the battery cell 1 and the capacity of the battery cell 1 satisfy the following relationship:

[0070] m = kC / 1000;

[0071] Among them, k is a constant, and the value range of k is 2.5-4. The value of k can be obtained through a large amount of experimental data.

[0072] In order to verify the correctness of 2.4≤S×P-C / (m×1000)≤5.4, a comparison of multiple groups of examples and comparative examples is performed below:

[0073] In the following embodiments and comparative examples, the battery cell 1 is a lithium iron phosphate battery cell 1. The parameters of each embodiment and comparative example are as follows:

[0074]

[0075] It can be seen from the above table that the values ​​calculated by the formula S×P-C / (m×1000) for Examples 1 to 4 are all within the range of 2.4 to 5.4, and the values ​​calculated by the formula S×P-C / (m×1000) for Comparative Examples 1 to 4 are not within the range of 2.4 to 5.4.

[0076] The battery cells 1 of Examples 1-4 and Comparative Examples 1-4 were subjected to overcharge tests respectively, and the specific test process was as follows:

[0077] Under the environment of 25℃, the battery cell 1 is charged with constant current and constant voltage at 0.5C current, with the cut-off voltage at 3.65V and the cut-off current at 0.05C. The battery cell 1 is discharged with constant current at 0.5C current to 2.5V, and the cycle is repeated 3 times. The discharge capacity of the last time is taken as the initial capacity and recorded as Q. The battery cell 1 is then charged with constant current and constant voltage at 0.5Q current, with a cut-off voltage of 3.65V and a cut-off current of 0.05Q. After being fully charged, it is continuously charged at 1Q until thermal runaway, and the valve opening SOC and thermal runaway SOC are recorded. The judgment standard of thermal runaway refers to the national standard GB38031-2020 for the safety of power battery cells 1 for electric vehicles. It should be noted that C refers to the nominal capacity of the battery cell 1, in Ah. The above 0.5C current indicates the current at a charge and discharge rate of half the nominal capacity. For a 100Ah battery cell 1, the 0.5C current is 50A, that is, the current rate at which the battery cell 1 is fully charged or discharged within 2 hours. Q is the discharge capacity after multiple charge and discharge cycles, in Ah, or ampere-hours, which is the remaining capacity when discharged to a specific voltage (such as 2.5V) under specified conditions. SOC (State of Charge) indicates the current remaining power percentage of the battery cell 1 and is used to describe the charging state of the battery cell 1. The SOC value range is usually 0% to 100%, 0% means completely empty, and 100% means fully charged. For example, in a charging test, the open valve SOC indicates the state of charge when the explosion-proof structure 122 is opened, and the thermal runaway SOC indicates the state of charge when the battery cell 1 reaches thermal runaway.

[0078] The following is a table of experimental results obtained from Examples 1-4 and Comparative Examples 1-4, respectively:

[0079] Open valve SOC / % Thermal runaway SOC / % Explosion Example 1 115 127 no Example 2 116 126 no Example 3 116 126 no Example 4 116 127 no Comparative Example 1 110 126 no Comparative Example 2 121 125 yes Comparative Example 3 114 118 no Comparative Example 4 113 121 yes

[0080] It can be seen from the above-mentioned embodiments 1-4 and comparative examples 1-4 that: embodiments 1-4 have opened the valve before reaching thermal runaway, and no explosion occurs; comparative example 1 opens the valve when overcharging to 110% SOC, and the valve opening SOC is too low to meet market demand; the valve opening pressure of comparative example 2 is too large, and the valve is opened at 121% SOC, and thermal runaway and explosion occur at 125% SOC; the injection volume of comparative example 3 is too high, and the valve opening pressure is too low, and the valve will open when overcharging to 114% SOC, which cannot meet market demand; the valve opening area of ​​comparative example 4 is set too small, and thermal runaway occurs at 121% SOC, followed by an explosion.

[0081] In summary, the staff set the valve opening area, valve opening pressure, electrolyte injection volume and capacity of the explosion-proof structure 122 in the battery cell 1 by referring to the formula 2.4≤S×P-C / (m×1000)≤5.4, which can adapt to battery cells 1 of various capacities, such as small-capacity battery cells 1 and large-capacity battery cells 1, so that the explosion-proof structure 122 can achieve timely valve opening and avoid premature valve opening.

[0082] The embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A battery cell, characterized in that: It comprises an electrode assembly and a shell, wherein the electrode assembly is arranged in the shell, and an explosion-proof structure is arranged on the shell; Among them, the valve opening area S of the explosion-proof structure, the valve opening pressure P of the explosion-proof structure, the injection amount m of the electrolyte of the battery cell and the capacity C of the battery cell satisfy the following formula: 2.4≤S×P-C / (m×1000)≤5.

4.

2. The battery cell according to claim 1, characterized in that: The explosion-proof structure is provided with a notch, and the depth of the notch and the valve opening area of ​​the explosion-proof structure satisfy the following relationship: 0.05≤d / S≤0.2; The length of the notch and the valve opening pressure of the explosion-proof structure satisfy the following relationship: L = β × 1 / P + γ; The width of the notch is inversely proportional to the valve opening area of ​​the explosion-proof structure; Wherein, d is the depth of the notch, S is the valve opening area of ​​the explosion-proof structure, L is the length of the notch, P is the valve opening pressure of the explosion-proof structure, and β and γ are both constants.

3. The battery cell according to claim 2, characterized in that: The total area of ​​the notches and the valve opening area satisfy the following relationship: S k =ζS; Among them, S k is the total area of ​​the notch, ζ is a constant, and the value range of ζ is 0.1-0.

3.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The valve opening area of ​​the explosion-proof structure satisfies the following relationship: S = αm + δ1; Wherein, α and δ1 are constants, and the value range of α is 1.2-1.8, and the value range of δ1 is 0.8-1.

8.

5. The battery cell according to claim 4, characterized in that: The value range of α is 1.4-1.6, and the value range of δ1 is 1.2-1.

5.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The electrolyte injection amount of the battery cell and the capacity of the battery cell satisfy the following relationship: m = kC / 1000; Wherein, k is a constant, and the value range of k is 2.5-4.

7. The battery cell according to any one of claims 1 to 3, characterized in that: The value range of the valve opening area S of the explosion-proof structure is 0.5-10cm 2 ; The value range of the valve opening pressure P of the explosion-proof structure is 0.5-1MPa; the value range of the electrolyte injection volume m of the battery cell is 0.25-3.2kg; the value range of the capacity C of the battery cell is 100-800Ah.

8. The battery cell according to claim 7, characterized in that: The value range of the valve opening area S of the explosion-proof structure is 2.5-5.0 cm 2 .

9. The battery cell according to any one of claims 1 to 3, characterized in that: The battery core comprises a cover plate, the cover plate is provided with the explosion-proof structure and has an explosion-proof hole, the explosion-proof hole is connected to the shell; the explosion-proof structure is provided on the cover plate and covers the explosion-proof hole.

10. The battery cell according to any one of claims 1 to 3, characterized in that: The active material of the battery cell is any one of an iron-lithium system, a medium-nickel ternary system, a high-nickel ternary system, a sodium-electric system, and a manganese iron phosphate lithium system.

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