A lead-acid battery and a method of operating the same

Abstract

The application provides a working method of a lead-acid storage battery, the lead-acid storage battery comprising a shell, a plurality of plates are arranged in the shell, and the plates are covered by AGM separators, the AGM separators have pores, and sulfuric acid electrolyte is adsorbed in the pores of the AGM separators, the working method of the lead-acid storage battery comprises a pre-charge-discharge stage, a mid-charge-discharge stage and a post-charge-discharge stage, in the pre-charge-discharge stage, all the pores of the AGM separators adsorb the sulfuric acid electrolyte, in the mid-charge-discharge stage and the post-charge-discharge stage, part of the pores of the AGM separators do not adsorb the sulfuric acid electrolyte. The application also protects a lead-acid storage battery as a secondary battery, and the lead-acid storage battery and the working method thereof can improve the service life of the lead-acid storage battery.

Description

Technical Field

[0001] This invention relates to the field of lead-acid batteries. Background Technology

[0002] Lead-acid batteries have a long history of development. The earliest lead-acid batteries were flooded lead-acid batteries. Although flooded lead-acid batteries had a long service life, they required frequent water addition, which was cumbersome and limited their application. Therefore, AGM lead-acid batteries were later invented. With their starved electrolyte design, they required virtually no maintenance and were widely used in electric bicycles. However, compared to flooded lead-acid batteries, AGM lead-acid batteries have a lifespan problem, becoming a major bottleneck for the industry's development. To improve the lifespan of AGM lead-acid batteries, the industry has conducted extensive research in various directions, including structural design, formulation design, and charging technology. How to further improve the lifespan of AGM lead-acid batteries is therefore of paramount importance. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for operating a lead-acid battery. The lead-acid battery includes a casing, and electrode plates covered by an AGM separator are installed inside the casing. The AGM separator has pores, and sulfuric acid electrolyte is adsorbed within the pores of the AGM separator. The method for operating the lead-acid battery includes an early charging / discharging stage, a mid-charging / discharging stage, and a late charging / discharging stage. In the early charging / discharging stage, all pores of the AGM separator adsorb sulfuric acid electrolyte. In the mid-charging / discharging stage and the late charging / discharging stage, some pores of the AGM separator do not adsorb sulfuric acid electrolyte.

[0004] This invention also provides another method for operating a lead-acid battery. The lead-acid battery includes a casing, and electrode plates covered by an AGM separator are installed inside the casing. The AGM separator has pores, and sulfuric acid electrolyte is adsorbed within the pores. The method for operating the lead-acid battery includes an early charge-discharge stage, a mid-term charge-discharge stage, and a late charge-discharge stage. The mid-term charge-discharge stage includes a first mid-term charge-discharge stage and a second mid-term charge-discharge stage. In the early charge-discharge stage, the number of charge-discharge cycles is N. 前 The density of the sulfuric acid electrolyte increases from ρ0 to ρ1, and during the first charge-discharge phase in the intermediate stage, the number of charge-discharge cycles is N. 中1 The density of the sulfuric acid electrolyte increases from ρ1 to ρ2, and during the second charge-discharge phase in the intermediate stage, the number of charge-discharge cycles is N. 中2 The density of the sulfuric acid electrolyte increases from ρ2 to ρ3, and in the later charge-discharge phase, the number of charge-discharge cycles is N. 后 The density of the sulfuric acid electrolyte increases from ρ3 to ρ 4， And it satisfies the following relationship: (ρ1-ρ0) / N前 Greater than (ρ2-ρ1) / N 中1， (ρ2-ρ1) / N 中1 Greater than (ρ3-ρ2) / N 中2， (ρ4-ρ3) / N 后 Greater than (ρ3-ρ2) / N 中2。

[0005] Furthermore, when the lead-acid battery enters the mid-term charge / discharge phase, the density of the sulfuric acid electrolyte is 1.26-1.4 g / cm³. 2 .

[0006] Furthermore, the charging and discharging reactions of the lead-acid battery during the charging and discharging stages are as follows: during charging, the lead sulfate of the positive electrode active material is converted into lead dioxide, and the lead sulfate of the negative electrode active material is converted into spongy lead; during discharging, the lead dioxide of the positive electrode active material is converted into lead sulfate, and the spongy lead of the negative electrode active material is also converted into lead sulfate.

[0007] This invention also protects a lead-acid battery as a secondary battery, the lead-acid battery comprising a casing, wherein an electrode plate covered by an AGM separator is installed inside the casing, the AGM separator having pores, and sulfuric acid electrolyte adsorbed within the pores of the AGM separator, the casing comprising a shell body and a shell cover covering the shell body, the AGM separator comprising an upper end and a lower end, wherein when the electrode plate is installed inside the shell body, the upper end of the AGM separator faces the shell cover, and a cavity is formed between the upper end of the AGM separator and the shell cover, the lead-acid battery further comprising free sulfuric acid electrolyte, the free sulfuric acid electrolyte being located within the cavity formed between the upper end of the AGM separator and the shell cover and covering the upper end of the AGM separator.

[0008] This invention also protects a lead-acid battery as a secondary battery, the lead-acid battery comprising a casing, wherein electrode plates covered by an AGM separator are installed inside the casing, the AGM separator has pores, and sulfuric acid electrolyte is adsorbed in the pores of the AGM separator, the casing comprising a shell body and a shell cover covering the shell body, the AGM separator comprising a wide side and a narrow side, characterized in that the lead-acid battery further comprises free sulfuric acid electrolyte, and a longitudinal gap is formed between the narrow side of the AGM separator and the shell body along the installation direction of the electrode plates, the free sulfuric acid electrolyte being located within the longitudinal gap formed between the narrow side of the electrode plates and the shell body and in contact with the AGM separator.

[0009] Furthermore, when free sulfuric acid electrolyte is present, all pores of the AGM separator are adsorbed with sulfuric acid electrolyte; when the free sulfuric acid electrolyte disappears, some pores of the AGM separator are not adsorbed with sulfuric acid electrolyte.

[0010] Furthermore, when some pores of the AGM separator do not adsorb sulfuric acid electrolyte, the density of the sulfuric acid electrolyte is less than or equal to 1.4 g / cm³. 2 .

[0011] The lead-acid battery and its working method of the present invention can improve the service life of lead-acid batteries. Attached Figure Description

[0012] Figure 1 This is a structural diagram of the lead-acid battery casing of the present invention;

[0013] Figure 2 This is a schematic diagram of the electrode plates of the lead-acid battery of the present invention, which are covered with AGM separators;

[0014] Figure 3 This is a schematic diagram of the casing cover of the lead-acid battery of the present invention;

[0015] Figure 4 This is a schematic diagram of a single cell of a lead-acid battery shown in the second embodiment of the lead-acid battery of the present invention;

[0016] Figure 5 This is a graph showing the change in the density of the sulfuric acid electrolyte with the number of charge-discharge cycles during the operation of the lead-acid battery of this invention. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments.

[0018] The first embodiment of the present invention, as follows: Figure 1 , 2As shown in Figure 3, a lead-acid battery includes a casing 1, which includes a casing body 101 and a casing cover 102 covering the casing body. At least one cell 1011 is formed inside the casing body 101. When the electrode plate 3 covered by the AGM separator 2 is installed inside the casing 1, it is installed in the cell 1011 of the casing body 101. The cell 1011 is usually formed by the side of the casing body 101 and the partition inside the casing body 101. The AGM separator 2 of the present invention includes a wide surface 203 and a narrow surface 204. When the electrode 3 covered by the AGM separator 2 is installed inside the housing 1, both the wide surface 203 and the narrow surface 204 of the AGM separator 2 form a sealed assembly with the individual cells 1011 of the housing 101. The tabs 3a of the electrode 3 extend out of the AGM separator 2, and the remaining part of the electrode 3 is covered by the AGM separator 2. The AGM separator 2 has pores, and sulfuric acid electrolyte 1001 is adsorbed in the pores of the AGM separator 2. The AGM separator 2 also includes an upper end 201 and a lower end 202. When the electrode 3 covered by the AGM separator 2 is installed inside the housing 101, the upper end 201 of the AGM separator 2 faces the housing cover 102, that is, faces the inner surface 1021 of the housing cover 102. A cavity 801 is formed between the upper end 201 of the AGM separator 2 and the cover 102. The free sulfuric acid electrolyte 1002 is located in the cavity 801 formed between the upper end 201 of the AGM separator 2 and the cover 102, and covers the upper end 201 of the AGM separator 2. When the free sulfuric acid electrolyte 1002 in the cavity 801 covers the upper end 201 of the AGM separator 2, there is no free sulfuric acid electrolyte at the lower end 202 of the AGM separator 2. This can avoid the effect of acid stratification on the plates during the operation of the lead-acid battery. In addition, it is best to leave a certain gap between the free sulfuric acid electrolyte 1002 and the inner surface 1021 of the cover 102. This can avoid the possible overflow of the free sulfuric acid electrolyte 1002 during the operation of the lead-acid battery and improve safety. The sulfuric acid electrolyte of the lead-acid battery of the present invention includes sulfuric acid electrolyte 1001 adsorbed in the pores of the AGM separator 2 and free sulfuric acid electrolyte. The free sulfuric acid electrolyte may include free sulfuric acid electrolyte 1002 in the cavity 801, and preferably consists of free sulfuric acid electrolyte 1002 in the cavity 801, which is the first embodiment of the present invention. When the lead-acid battery is working, when free sulfuric acid electrolyte 1002 is present in the cavity 801, all pores of the AGM separator 2 are adsorbed with sulfuric acid electrolyte; when the free sulfuric acid electrolyte in the cavity 801 disappears, some pores of the AGM separator 2 are not adsorbed with sulfuric acid electrolyte. When some pores of the AGM separator 2 are not adsorbed with sulfuric acid electrolyte, the density of the sulfuric acid electrolyte is preferably less than or equal to 1.4 g / cm³. 2 .

[0019] Furthermore, in a second embodiment of the present invention, such as Figure 4As shown, another method for storing the free sulfuric acid electrolyte 1002 is also disclosed. The AGM separator 2 includes a wide surface 203 and a narrow surface 204. A longitudinal gap is formed between the narrow surface 204 of the AGM separator 2 (which does not bear assembly pressure) and the housing 101 along the installation direction of the electrode plate 3, that is, between the narrow surface 204 and the housing 101. The free sulfuric acid electrolyte can also be located within the longitudinal gap 1012 formed between the narrow surface 204 of the electrode plate 3 (which does not bear assembly pressure) and the housing 101. When the free sulfuric acid electrolyte is located within the longitudinal gap 1012, it is in contact with the AGM separator 2. This invention provides a lead-acid battery... The sulfuric acid electrolyte in the cell includes sulfuric acid electrolyte 1001 adsorbed in the pores of the AGM separator 2 and free sulfuric acid electrolyte. The free sulfuric acid electrolyte includes free sulfuric acid electrolyte 1003 in the longitudinal gap 1012, preferably consisting of free sulfuric acid electrolyte 1003 in the longitudinal gap 1012. Compared to the solution described in the third embodiment below, where free sulfuric acid electrolyte 1002 exists in the cavity formed between the upper end of the AGM separator and the shell cover, and free sulfuric acid electrolyte 1003 also exists in the longitudinal gap 1012, the impact of acid stratification on the electrode plates can be appropriately reduced. When free sulfuric acid electrolyte is present within the longitudinal gap 1012, all pores of the AGM separator 2 are filled with sulfuric acid electrolyte. When the free sulfuric acid electrolyte disappears from the longitudinal gap, only a portion of the pores of the AGM separator 2 are filled with sulfuric acid electrolyte. When only a portion of the pores of the AGM separator 2 are filled with sulfuric acid electrolyte, the density of the sulfuric acid electrolyte is preferably less than or equal to 1.4 g / cm³. 2 While this solution can also extend the lifespan of lead-acid batteries, compared to the solution where the free sulfuric acid electrolyte is only located in the cavity formed between the upper end of the AGM separator and the casing, this solution causes acid stratification along the installation direction of plate 3, which will have an adverse effect on the lead-acid battery plates. In addition, it is not conducive to the production using current AGM lead-acid battery manufacturing processes.

[0020] In another third embodiment of the present invention, the sulfuric acid electrolyte of the lead-acid battery includes sulfuric acid electrolyte 1001 adsorbed in the pores of the AGM separator 2 and free sulfuric acid electrolyte. The free sulfuric acid electrolyte includes free sulfuric acid electrolyte 1002 in the cavity formed between the upper end of the AGM separator and the shell cover, and free sulfuric acid electrolyte in the elongated gap formed between the narrow surface 204 of the electrode plate 3 (which does not bear assembly pressure) and the shell 101. Preferably, it is composed of free sulfuric acid electrolyte 1002 in the cavity formed between the upper end of the AGM separator and the shell cover, and free sulfuric acid electrolyte 1003 in the elongated gap formed between the narrow surface 204 of the electrode plate 3 (which does not bear assembly pressure) and the shell 101. Compared with the second embodiment, although this scheme may have some adverse effects on the electrode plates due to acid stratification due to the addition of relatively more free sulfuric acid electrolyte, it can extend the service life of the lead-acid battery overall.

[0021] This invention also discloses a method for operating the lead-acid battery of this invention, including an early charging / discharging stage, a mid-charging / discharging stage, and a late charging / discharging stage. The charging / discharging reactions of the lead-acid battery of this invention during the charging / discharging stages are as follows: During charging, the lead sulfate in the positive electrode active material is converted into lead dioxide, and the lead sulfate in the negative electrode active material is converted into spongy lead. The sulfuric acid component in the active material is released into the electrolyte, and the concentration of sulfuric acid in the electrolyte continuously increases, the battery voltage rises, and energy is accumulated. When the battery discharges, the lead dioxide in the positive electrode active material is converted into lead sulfate, and the spongy lead in the negative electrode active material is also converted into lead sulfate, and absorbs the sulfuric acid in the electrolyte. The concentration of sulfuric acid in the electrolyte continuously decreases, the battery voltage drops, and the battery outputs energy. In the early charging / discharging stage, all the pores of the AGM separator are adsorbed with sulfuric acid electrolyte. In the mid-charging / discharging stage and the late charging / discharging stage, some of the pores of the AGM separator are adsorbed with sulfuric acid electrolyte. Another method for operating the lead-acid battery of the present invention includes an early charge-discharge stage, a mid-charge-discharge stage, and a late charge-discharge stage. The mid-charge-discharge stage includes a first mid-term charge-discharge stage and a second mid-term charge-discharge stage. In the early charge-discharge stage, the number of charge-discharge cycles is N. 前 The density of the sulfuric acid electrolyte increases from ρ0 to ρ1. During the first charge-discharge phase in the middle stage, the number of charge-discharge cycles is N. 中1 The density of the sulfuric acid electrolyte increases from ρ1 to ρ2. During the second charge-discharge phase in the middle stage, the number of charge-discharge cycles is N. 中2 The density of the sulfuric acid electrolyte increases from ρ2 to ρ3. During the later charge / discharge phase, the number of charge / discharge cycles is N. 后 The density of the sulfuric acid electrolyte increases from ρ3 to ρ 4， And it satisfies the following relationship: (ρ1-ρ0) / N 前 Greater than (ρ2-ρ1) / N 中1， (ρ2-ρ1) / N 中1 Greater than (ρ3-ρ2) / N中2， (ρ4-ρ3) / N 后 Greater than (ρ3-ρ2) / N 中2。 When the lead-acid battery of the present invention enters the mid-term charge-discharge stage, the density of the sulfuric acid electrolyte is preferably 1.26-1.4 g / cm³. 2 The density ρ of the sulfuric acid electrolyte of this invention 0、 ρ1, ρ 2、 ρ 3、 ρ4 can be the density of the sulfuric acid electrolyte at the same depth of charge under different charging cycles or at the same depth of discharge under different discharging cycles. For example, ρ0 is the initial density of the sulfuric acid electrolyte when the lead-acid battery is initially fully charged, and ρ1 is the number of charge-discharge cycles N. 前 At that time, ρ2 is the density of the sulfuric acid electrolyte after the last full charge, and N is the number of charge-discharge cycles. 中1 At that time, ρ3 is the density of the sulfuric acid electrolyte after the last full charge, and N is the number of charge-discharge cycles. 中2 At that time, ρ4 represents the density of the sulfuric acid electrolyte after the last full charge, and N represents the number of charge-discharge cycles. 后 At that time, the density of the sulfuric acid electrolyte after the last full charge is as follows: Figure 5 As shown. Furthermore, charging and discharging can be performed based on a 100% depth of discharge, or on other suitable depths of discharge such as 70%, without affecting the purpose of this invention.

[0022] The charge-discharge reaction of the lead-acid battery of this invention refers to the charge-discharge reaction when the lead-acid battery is working as a secondary battery to provide energy to an external load after its formation. The reaction is as follows: During charging, the lead sulfate in the positive electrode active material is converted into lead dioxide, and the lead sulfate in the negative electrode active material is converted into spongy lead. The sulfuric acid component in the active material is released into the electrolyte, and the sulfuric acid concentration in the electrolyte continuously increases, causing the battery voltage to rise and energy to accumulate. During discharging, the lead dioxide in the positive electrode active material is converted into lead sulfate, and the spongy lead in the negative electrode active material is also converted into lead sulfate, absorbing sulfuric acid from the electrolyte. The sulfuric acid concentration in the electrolyte continuously decreases, the battery voltage decreases, and the battery outputs energy. The working method of the lead-acid battery of this invention refers to the working method when the lead-acid battery is working as a secondary battery, that is, when it is working as a secondary battery to provide energy to an external load. The lead-acid battery of this invention refers to a lead-acid battery that can provide energy to an external load as a secondary battery after production.

[0023] In the design of the lead-acid battery of the present invention, depending on whether it is a lead-acid battery for energy storage or a lead-acid battery for power, the density of the sulfuric acid electrolyte in the lead-acid battery for energy storage is preferably controlled at 1.26-1.34 g / cm³ during the initial stage of the mid-term charge-discharge phase, that is, at the beginning of entering the mid-term charge-discharge phase. 2The optimal density of sulfuric acid electrolyte in lead-acid batteries for power applications is 1.34-1.4 g / cm³. 2 This allows for the extension of the lifespan of lead-acid batteries while still meeting their performance requirements.

[0024] The lead-acid battery of this invention can pre-store sulfuric acid electrolyte within the cavity formed between the upper end of the AGM separator and the casing, or (and) the elongated gap formed between the narrow face of the electrode plate and the casing. Throughout the entire charge-discharge lifespan of the lead-acid battery, in the early charge-discharge phase, the AGM separator operates at a saturation level greater than or equal to 100%. As the early charge-discharge phase ends and the battery enters the mid-charge-discharge phase, the AGM separator operates at a saturation level below 100%. This further extends the lifespan of the lead-acid battery while requiring no maintenance, thus forming the maintenance-free secondary lead-acid battery of this invention. Furthermore, for lead-acid batteries with less stringent dimensional requirements, especially energy storage lead-acid batteries, the lifespan can be further improved by further increasing the cavity formed between the upper end of the AGM separator and the casing.

[0025] This invention also discloses a formation method for an AGM lead-acid battery, including acid formation. After acid formation, the AGM lead-acid battery contains residual free sulfuric acid electrolyte. There is no step of removing the residual free sulfuric acid electrolyte after acid formation. The volume and density of the residual free sulfuric acid electrolyte satisfy the following conditions: when the AGM lead-acid battery is used as a secondary battery for charging and discharging, the sulfuric acid electrolyte density is maintained at 1.26-1.4 g / cm³ when the free sulfuric acid electrolyte disappears. 2 This simplifies the formation process and extends the lifespan of lead-acid batteries. The charging and discharging reactions of an AGM lead-acid battery as a secondary battery are as follows: During charging, lead sulfate in the positive electrode active material is converted to lead dioxide, and lead sulfate in the negative electrode active material is converted to spongy lead; during discharging, lead dioxide in the positive electrode active material is converted to lead sulfate, and spongy lead in the negative electrode active material is also converted to lead sulfate.

[0026] The charging and discharging reactions during the acid formation of AGM lead-acid batteries include the formation reaction in which lead oxide, 3BS, and 1BS are converted into lead dioxide, and the salting reaction in which lead oxide, 3BS, and 1BS are converted into lead sulfate. The charging and discharging reactions during the operation of AGM lead-acid batteries as secondary batteries do not include the formation reaction in which lead oxide, 3BS, and 1BS are converted into lead dioxide.

[0027] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A method for operating a lead-acid battery, the lead-acid battery comprising a casing, the casing comprising a body and a cover covering the body, wherein plates covered by an AGM separator are installed inside the casing, the AGM separator having pores, sulfuric acid electrolyte being adsorbed within the pores of the AGM separator, the AGM separator comprising an upper end and a lower end, a cavity being formed between the upper end of the AGM separator and the cover, the AGM separator comprising a wide face and a narrow face, a longitudinal gap being formed between the narrow face of the AGM separator (not bearing assembly pressure) and the body along the installation direction of the plates, the method for operating the lead-acid battery comprising an early charging / discharging stage, a mid-charging / discharging stage, and a late charging / discharging stage, characterized in that... During the initial charge-discharge phase, the cavity or the longitudinal gap contains free sulfuric acid electrolyte, and all pores of the AGM separator are adsorbed with sulfuric acid electrolyte. During the intermediate charge-discharge phase and the later charge-discharge phase, the cavity or the longitudinal gap does not contain free sulfuric acid electrolyte, and some pores of the AGM separator do not adsorb sulfuric acid electrolyte.

2. A method for operating a lead-acid battery, the lead-acid battery comprising a casing, the casing comprising a body and a cover covering the body, an electrode plate covered by an AGM separator being installed inside the casing, the AGM separator having pores, sulfuric acid electrolyte being adsorbed within the pores of the AGM separator, the AGM separator comprising an upper end and a lower end, a cavity being formed between the upper end of the AGM separator and the cover, the AGM separator comprising a wide face and a narrow face, a longitudinal gap being formed between the narrow face of the AGM separator (not bearing assembly pressure) and the body along the installation direction of the electrode plate, the method for operating the lead-acid battery comprising an early charging / discharging stage, a mid-stage charging / discharging stage, and a late charging / discharging stage, the mid-stage charging / discharging stage comprising a first mid-stage charging / discharging stage and a second mid-stage charging / discharging stage, characterized in that... During the initial charge-discharge phase, free sulfuric acid electrolyte exists in the cavity or the longitudinal gap, and the number of charge-discharge cycles is N. 前 The density of the sulfuric acid electrolyte increases from ρ0 to ρ1. During the first charge-discharge phase in the intermediate stage, there is no free sulfuric acid electrolyte in the cavity or the longitudinal gap, and the number of charge-discharge cycles is N. 中1 The density of the sulfuric acid electrolyte increases from ρ1 to ρ2. During the second charge-discharge phase in the intermediate stage, there is no free sulfuric acid electrolyte in the cavity or the longitudinal gap, and the number of charge-discharge cycles is N. 中2 The density of the sulfuric acid electrolyte increases from ρ2 to ρ3. During the later charge-discharge phase, there is no free sulfuric acid electrolyte in the cavity or the longitudinal gap, and the number of charge-discharge cycles is N. 后 The density of the sulfuric acid electrolyte increases from ρ3 to ρ 4， ρ 0、 ρ1, ρ 2、 ρ 3、 ρ4 is the density of the sulfuric acid electrolyte at the same depth of charge under different charging cycles or at the same depth of discharge under different discharging cycles, and satisfies the following relationship: (ρ1-ρ0) / N 前 Greater than (ρ2-ρ1) / N 中1， (ρ2-ρ1) / N 中1 Greater than (ρ3-ρ2) / N 中2， (ρ4-ρ3) / N 后 Greater than (ρ3-ρ2) / N 中2。 3. The working method of a lead-acid battery as described in claim 1 or 2, characterized in that, When the lead-acid battery enters the mid-term charge-discharge stage, the density of the sulfuric acid electrolyte is 1.26-1.4 g / cm³. 2 .

4. The operating method of a lead-acid battery as described in claim 1 or 2, characterized in that, The working method refers to the working method when the lead-acid battery is used as a secondary battery. The charging and discharging reactions of the lead-acid battery are as follows: during charging, the lead sulfate of the positive electrode active material is converted into lead dioxide, and the lead sulfate of the negative electrode active material is converted into spongy lead; during discharging, the lead dioxide of the positive electrode active material is converted into lead sulfate, and the spongy lead of the negative electrode active material is also converted into lead sulfate.

5. A lead-acid battery as a secondary battery, the lead-acid battery comprising a casing, wherein electrode plates covered by an AGM separator are installed inside the casing, the AGM separator having pores, and sulfuric acid electrolyte is adsorbed within the pores of the AGM separator, the casing comprising a shell body and a shell cover covering the shell body, the AGM separator comprising a wide side and a narrow side, characterized in that, The lead-acid battery refers to a lead-acid battery that can provide energy to an external load as a secondary battery after production. During the initial charging and discharging stage of operation, it also includes free sulfuric acid electrolyte. The narrow side of the AGM separator and the shell form a longitudinal gap along the installation direction of the electrode plate. The free sulfuric acid electrolyte is located in the longitudinal gap formed between the narrow side of the electrode plate and the shell and is in contact with the AGM separator.

6. A lead-acid battery as a secondary battery as described in claim 5, characterized in that, The lead-acid battery refers to a secondary battery that can provide energy to an external load after production. When free sulfuric acid electrolyte is present, all pores of the AGM separator are adsorbed with sulfuric acid electrolyte; when the free sulfuric acid electrolyte disappears, some pores of the AGM separator are not adsorbed with sulfuric acid electrolyte.

7. A lead-acid battery as a secondary battery as described in claim 6, characterized in that, When some pores of the AGM separator do not adsorb sulfuric acid electrolyte, the density of the sulfuric acid electrolyte is less than or equal to 1.4 g / cm³. 2 .

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