CN220209102U - Cylindrical battery and energy storage system - Google Patents

Abstract

The utility model relates to the technical field of cylindrical batteries, in particular to a cylindrical battery and an energy storage system. The cylindrical battery comprises a first straight cylindrical steel shell, a pole group, a positive pole cap and a negative pole cap, wherein the first straight cylindrical steel shell extends along a first direction, the pole group is assembled in the first straight cylindrical steel shell, the positive pole cap and the negative pole cap are respectively arranged on two sides of the pole group in the first direction, the positive pole cap is electrically connected with a positive pole piece of the pole group, and the negative pole cap is electrically connected with a negative pole piece of the pole group; specifically, the first straight cylinder steel shell is a straight cylinder steel shell, both ends of the first straight cylinder steel shell are provided with first openings, a stretching process is not needed when the straight cylinder steel shell is manufactured, and the first straight cylinder steel shell can be made larger than the steel shell in the prior art due to the fact that the first straight cylinder steel shell is not limited by the stretching process.

Description

Cylindrical battery and energy storage system

Technical Field

The utility model relates to the field of cylindrical batteries, in particular to a cylindrical battery and an energy storage system.

Background

The application of the large-capacity cylindrical battery is very wide, for example, in an electric vehicle, the volume density ratio of the power battery pack of the electric vehicle can be greatly improved by making the cylindrical battery, so that the number of the battery packs is reduced, and the cost of the battery packs is reduced, and therefore, research and development personnel are constantly striving to develop the cylindrical battery with larger size.

In the prior art, a stretching process is needed when a steel shell of a cylindrical battery is manufactured, and the stretching process is limited by factors such as a stretching die, materials, material thickness and the like, so that the size of the steel shell produced in mass by using the stretching process is limited, and the cylindrical battery cannot be manufactured to be large.

Disclosure of Invention

The technical problem to be solved by the embodiment of the utility model is to provide a cylindrical battery and an energy storage system, so as to solve the problem that the cylindrical battery cannot be made large due to the limited size of a steel shell in the prior art.

In a first aspect, an embodiment of the present utility model provides a cylindrical battery, including: the first cylinder type steel shell extends along a first direction, and both ends of the first cylinder type steel shell are provided with first openings; the pole group is arranged in the first straight cylinder steel shell; the positive electrode cap is arranged on one side of the electrode group in the first direction and is electrically connected with the positive electrode plate of the electrode group; the negative electrode cap is arranged on one side of the electrode group, which is far away from the positive electrode cap, and is electrically connected with the negative electrode plate of the electrode group.

Further, the battery pack comprises a second straight cylinder steel shell, wherein the second straight cylinder steel shell extends along the first direction, two ends of the second straight cylinder steel shell are respectively provided with a second opening, the second straight cylinder steel shell is arranged in the first straight cylinder steel shell, and the pole group, the positive pole cap and the negative pole cap are respectively arranged between the first straight cylinder steel shell and the second straight cylinder steel shell.

Further, the device also comprises a first insulation structure and a second insulation structure; the first insulation structure is arranged between the positive electrode cap and the first straight cylinder steel shell and between the positive electrode cap and the second straight cylinder steel shell; the second insulation structure is arranged between the negative electrode cap and the first straight cylinder steel shell, and between the negative electrode cap and the second straight cylinder steel shell.

Further, the first insulation structure comprises a first outer ring insulation sleeve and a first inner ring insulation sleeve, the first outer ring insulation sleeve is sleeved on the outer ring of the positive electrode cap, and the first inner ring insulation sleeve is sleeved on the inner ring of the positive electrode cap.

Further, the second insulation structure comprises a second outer ring insulation sleeve and a second inner ring insulation sleeve, the second outer ring insulation sleeve is sleeved on the outer ring of the negative electrode cap, and the second inner ring insulation sleeve is sleeved on the inner ring of the negative electrode cap.

Further, be equipped with on the first straight section of thick bamboo shaped steel shell towards two first bellying that the second straight section of thick bamboo shaped steel shell set up, two first bellying is in the interval sets up in the first direction, be equipped with two second bellying on the second straight section of thick bamboo shaped steel shell, two the second bellying respectively with two first bellying is relative, the limit of group sets up in two in the first installation space that first bellying and two second bellying prescribe a limit to jointly.

Further, one end of the first straight cylinder steel shell is provided with a first folding edge part which is bent towards the second straight cylinder steel shell, one end of the second straight cylinder steel shell is provided with a second folding edge part which is opposite to the first folding edge part, and the first folding edge part, the second folding edge part, the first protruding part and the second protruding part which are adjacent to the first folding edge part and the second folding edge part together define a second installation space, and the positive electrode cap is limited in the second installation space.

Further, one end of the first straight cylinder steel shell is provided with a third folded edge part which is bent towards the second straight cylinder steel shell, one end of the second straight cylinder steel shell is provided with a fourth folded edge part which is opposite to the third folded edge part, the fourth folded edge part, the first protruding part and the second protruding part which are adjacent to the third folded edge part and the fourth folded edge part are jointly limited to form a third installation space, and the negative electrode cap is limited to be installed in the third installation space.

Further, the anti-explosion device further comprises an anti-explosion ball and a positive electrode convex cap, a through hole arranged along the first direction is formed in the positive electrode cap, the anti-explosion ball is blocked on one side, opposite to the electrode group, of the through hole, and the anti-explosion ball is clamped between the positive electrode convex cap and the positive electrode cap.

In a second aspect, an embodiment of the present utility model further provides an energy storage system, including a battery pack and a water cooling device, where the battery pack includes a plurality of the cylindrical batteries described in the first aspect, and the water cooling device includes a water cooling pipe for flowing a water-cooling solution, and the water cooling pipe is disposed through a second straight cylindrical steel shell of the cylindrical battery.

Compared with the prior art, the cylindrical battery and the energy storage system provided by the embodiment of the utility model have the beneficial effects that: the cylindrical battery comprises a first straight cylindrical steel shell, a pole group, a positive pole cap and a negative pole cap, wherein the first straight cylindrical steel shell extends along a first direction, the pole group is assembled in the first straight cylindrical steel shell, the positive pole cap and the negative pole cap are respectively arranged on two sides of the pole group in the first direction, the positive pole cap is electrically connected with a positive pole piece of the pole group, and the negative pole cap is electrically connected with a negative pole piece of the pole group; specifically, the first straight cylinder steel shell is a straight cylinder steel shell, both ends of the first straight cylinder steel shell are provided with first openings, a stretching process is not needed when the straight cylinder steel shell is manufactured, and the first straight cylinder steel shell can be made larger than the steel shell in the prior art due to the fact that the first straight cylinder steel shell is not limited by the stretching process.

Drawings

The utility model will now be described in further detail with reference to the accompanying drawings and examples, in which:

fig. 1 is a schematic view of a structure of a prior art cylindrical battery;

fig. 2 is a schematic structural view of a cylindrical battery according to an embodiment of the present utility model;

fig. 3 is a schematic structural view of a first straight cylinder steel shell and a second straight cylinder steel shell according to an embodiment of the present utility model;

FIG. 4 is an enlarged schematic view of a portion of the position A of FIG. 2;

FIG. 5 is a schematic view of a water cooling pipe and a battery pack according to an embodiment of the present utility model;

fig. 6 is a schematic structural diagram of a heat dissipating block, a pump body, heat dissipating fins, and a fan according to an embodiment of the present utility model.

The reference numerals in the drawings are as follows:

100. a battery pack; 110. a cylindrical battery; 111. a first straight cylinder steel shell; 1111. a first opening; 1112. a first boss; 1113. a first groove; 1114. a first folded edge portion; 1115. a third groove; 1116. a third folded edge portion; 1117. a fifth groove; 112. a pole group; 113. an anode cap; 1131. a through hole; 114. a negative electrode cap; 115. the second straight cylinder type steel shell; 1151. a second opening; 1152. a second protruding portion; 1153. a second groove; 1154. a second flange portion; 1155. a fourth groove; 1156. a fourth folded edge portion; 1157. a sixth groove; 116. a first insulating structure; 1161. a first outer ring insulating sleeve; 1162. a first inner ring insulating sleeve; 117. a second insulating structure; 1171. a second outer ring insulating sleeve; 1172. a second inner ring insulating sleeve; 118. explosion-proof ball; 119. positive pole protruding cap;

210. a water-cooled pipeline; 220. a heat dissipation block; 230. a pump body; 240. a heat radiation fin; 250. a fan;

9000. a steel shell; 9100. a bottom wall; 9200. a sidewall.

Detailed Description

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. Preferred embodiments of the present utility model will now be described in detail with reference to the accompanying drawings.

Referring to fig. 1, a steel case 9000 of a cylindrical battery in the prior art includes a bottom wall 9100 and a side wall 9200 provided around the bottom wall 9100, and the steel case 9000 is required to be manufactured by a drawing process, and the drawing process is limited by factors such as a drawing die, a material, a thickness of the material, and the like, so that the size of the steel case 9000 mass-produced by the drawing process is limited, thereby making the cylindrical battery impossible to be large.

In order to solve the above technical problems, an embodiment of the present utility model provides a cylindrical battery 110, as shown in fig. 2 and 3, the cylindrical battery 110 includes a first cylindrical steel can 111, a pole group 112, a positive electrode cap 113, and a negative electrode cap 114. The first cylinder type steel shell 111 extends in the first direction, and both ends of the first cylinder type steel shell 111 have first openings 1111. The pole group 112 is installed in the first cylindrical steel shell 111, the positive pole cap 113 is installed at one side of the pole group 112 in the first direction, the positive pole cap 113 is electrically connected with the positive pole piece of the pole group 112, the negative pole cap 114 is installed at one side of the pole group 112 far away from the positive pole cap 113, and the negative pole cap 114 is electrically connected with the negative pole piece of the pole group 112.

Specifically, the cylindrical battery 110 of the present embodiment employs the first cylindrical steel shell 111, and the first cylindrical steel shell 111 is different from the steel shell 9000 in the prior art in that the first cylindrical steel shell 111 is a cylindrical steel shell, and both ends of the first cylindrical steel shell have the first openings 1111, so that the cylindrical steel shell does not need to be manufactured by a stretching process, and the first cylindrical steel shell 111 can be made larger than the steel shell 9000 in the prior art due to the limitation of the stretching process. Since the two ends of the first cylindrical steel shell 111 have openings, the cylindrical battery 110 of the embodiment is further provided with a cathode cap 114 in addition to the cathode cap 113, the cathode cap 113 and the cathode cap 114 are respectively mounted on two sides of the electrode group 112 in the first direction, wherein the cathode cap 113 is electrically connected with the cathode plate of the electrode group 112, and the cathode cap 114 is electrically connected with the anode plate of the electrode group 112.

Referring to fig. 2 and 3, in an embodiment, the cylindrical battery 110 further includes a second straight cylindrical steel shell 115, the second straight cylindrical steel shell 115 also extends along the first direction, two ends of the second straight cylindrical steel shell 115 are respectively provided with a second opening 1151, the second straight cylindrical steel shell 115 is installed in the first straight cylindrical steel shell 111, and the electrode group 112, the positive electrode cap 113 and the negative electrode cap 114 are respectively installed between the first straight cylindrical steel shell 111 and the second straight cylindrical steel shell 115.

Specifically, the second straight cylindrical steel shell 115 is also a straight cylindrical steel shell, and both ends thereof have the second openings 1151, so that the second straight cylindrical steel shell 115 does not need to be manufactured by a drawing process, and the size thereof is not limited by the drawing process. The pole group 112, the positive pole cap 113 and the negative pole cap 114 are arranged between the first straight cylinder steel shell 111 and the second straight cylinder steel shell 115, so that the pole group 112, the positive pole cap 113 and the negative pole cap 114 can be prevented from blocking the second opening 1151. After exposing the second opening 1151, a channel is formed in the middle of the cylindrical battery 110, and the cylindrical battery 110 can dissipate heat through the channel.

It should be noted that, in the prior art, the middle of the cylindrical battery 110 is sealed, and the cylindrical battery 110 performs heat exchange with the outside mainly through the outer peripheral wall, so the heat dissipation effect is relatively poor, and after the embodiment is implemented, the heat dissipation area of the cylindrical battery 110 is larger, which is beneficial to heat dissipation of the cylindrical battery 110.

Referring to fig. 2 and 3, in the first aspect, the cylindrical battery 110 is easily aged in a high-temperature environment, thereby reducing the service life of the cylindrical battery 110. Therefore, by implementing the embodiment, the aging of the cylindrical battery 110 can be delayed, thereby prolonging the service life of the cylindrical battery 110

In the second aspect, the cylindrical battery 110 is susceptible to accidents such as fires, explosions, etc. under high temperature environments. The safety performance of the cylindrical battery 110 can be improved by implementing the present embodiment.

In the third aspect, the larger the size of the cylindrical battery 110, the larger the heat dissipation requirement, and if the heat dissipation capability of the cylindrical battery 110 cannot be improved, the larger the cylindrical battery 110 will be affected. Since the heat dissipation capacity of the cylindrical battery 110 can be improved by implementing the present embodiment, the cylindrical battery 110 can be made larger.

Referring to fig. 2, in an embodiment, the cylindrical battery 110 further includes a first insulation structure 116 and a second insulation structure 117, the first insulation structure 116 is disposed between the positive electrode cap 113 and the first straight cylindrical steel shell 111, and between the positive electrode cap 113 and the second straight cylindrical steel shell 115, and the second insulation structure 117 is disposed between the negative electrode cap 114 and the first straight cylindrical steel shell 111, and between the negative electrode cap 114 and the second straight cylindrical steel shell 115.

Specifically, if the positive electrode cap 113 and the negative electrode cap 114 are electrically connected to the first cylindrical shell 111 or the second cylindrical shell 115, the cylindrical battery 110 may be short-circuited, resulting in safety accidents such as overheating, ignition, explosion, etc. of the cylindrical battery 110. In order to solve this technical problem, in this embodiment, a first insulation structure 116 is disposed between the positive electrode cap 113 and the first straight tube shaped steel shell 111, and between the positive electrode cap 113 and the second straight tube shaped steel shell 115, so as to avoid the situation that the positive electrode cap 113 is electrically connected with the first straight tube shaped steel shell 111 and the second straight tube shaped steel shell 115; in this embodiment, a second insulation structure 117 is further disposed between the negative electrode cap 114 and the first straight tube shaped steel shell 111, and between the negative electrode cap 114 and the second straight tube shaped steel shell 115, so as to avoid the situation that the negative electrode cap 114 is electrically connected with the first straight tube shaped steel shell 111 and the second straight tube shaped steel shell 115.

Referring to fig. 2, in an embodiment, the first insulation structure 116 includes a first outer ring insulation sleeve 1161 and a first inner ring insulation sleeve 1162, where the first outer ring insulation sleeve 1161 is sleeved on the outer ring of the anode cap 113, so as to avoid the situation that the anode cap 113 is electrically connected with the first cylindrical steel shell 111; the first inner ring insulating sleeve 1162 is sleeved on the inner ring of the anode cap 113, so as to avoid the situation that the anode cap 113 is electrically connected with the second straight cylinder steel shell 115. The first outer ring insulating sleeve 1161 and the first inner ring insulating sleeve 1162 are very convenient to install, and the first outer ring insulating sleeve 1161 and the first inner ring insulating sleeve 1162 are sleeved on the outer ring and the inner ring of the positive electrode cap 113 when the positive electrode cap is installed.

Referring to fig. 2, in an embodiment, the second insulation structure 117 includes a second outer ring insulation sleeve 1171 and a second inner ring insulation sleeve 1172, where the second outer ring insulation sleeve 1171 is sleeved on the outer ring of the negative cap 114, so as to avoid the situation that the negative cap 114 is electrically connected with the first cylindrical steel shell 111; the second inner ring insulating sleeve 1172 is sleeved on the inner ring of the negative electrode cap 114, so as to avoid the situation that the negative electrode cap 114 is electrically connected with the second straight cylinder steel shell 115. The second outer-ring insulating sleeve 1171 and the second inner-ring insulating sleeve 1172 are very convenient to install, and the second outer-ring insulating sleeve 1171 and the second inner-ring insulating sleeve 1172 are sleeved on the outer ring and the inner ring of the cathode cap 114 respectively during installation.

Referring to fig. 2 and 3, in an embodiment, two first protrusions 1112 disposed towards the second straight-tube shaped steel shell 115 are disposed on the first straight-tube shaped steel shell 111, the two first protrusions 1112 are disposed at intervals in the first direction, two second protrusions 1152 are disposed on the second straight-tube shaped steel shell 115, the two second protrusions 1152 are opposite to the two first protrusions 1112, and the pole group 112 is limited in a first installation space defined by the two first protrusions 1112 and the two second protrusions 1152.

Specifically, a first groove 1113 is formed between the two first protrusions 1112, a second groove 1153 is formed between the two second protrusions 1152, and the pole group 112 installed in the first installation space is constrained by the groove wall of the first groove 1113 and the groove wall of the second groove 1153, so that the pole group 112 cannot move in the first direction in the first straight-tube steel shell 111 after implementing the present embodiment.

It should be noted that, the two first protrusions 1112 and the two second protrusions 1152 may be formed by a channeling process, and the channeling process is known to those skilled in the art, so this patent is not repeated herein. Of course, it should be understood that if other processes can be used to manufacture the first protrusions 1112 and the second protrusions 1152, other processes can be used, and the present embodiment is not limited to the above process.

Referring to fig. 2 and 3, in one embodiment, one end of the first straight tubular shell 111 is provided with a first flange 1114 bent toward the second straight tubular shell 115, and one end of the second straight tubular shell 115 is provided with a second flange 1154 disposed opposite the first flange 1114. The first and second flange portions 1114 and 1154 and the first and second protrusions 1112 and 1152 adjacent thereto define a second installation space, and the positive cap 113 is limitedly installed in the second installation space.

Specifically, a third groove 1115 is formed between the first flange 1114 and the first protrusion 1112 adjacent thereto, a fourth groove 1155 is formed between the second flange 1154 and the second protrusion 1152 adjacent thereto, and the positive electrode cap 113 installed in the second installation space is constrained by the walls of the third groove 1115 and the fourth groove 1155, so that the positive electrode cap 113 cannot move in the first direction in the first cylindrical shell 111 after implementing the present embodiment.

Referring to fig. 2 and 3, in one embodiment, one end of the first straight tube shell 111 is provided with a third folded edge portion 1116 folded toward the second straight tube shell 115, and one end of the second straight tube shell 115 is provided with a fourth folded edge portion 1156 disposed opposite to the third folded edge portion 1116. The third folded edge 1116, the fourth folded edge 1156, and the first and second protrusions 1112 and 1152 adjacent thereto define a third installation space, and the positive cap 113 is limitedly installed in the third installation space.

Specifically, a fifth groove 1117 is formed between the third folded edge 1116 and the first protruding portion 1112 adjacent thereto, a sixth groove 1157 is formed between the fourth folded edge 1156 and the second protruding portion 1152 adjacent thereto, and the negative electrode cap 114 installed in the third installation space is constrained by the walls of the fifth groove 1117 and the sixth groove 1157, so that the negative electrode cap 114 cannot move in the first direction within the first cylindrical shell 111 after implementing the present embodiment.

It should be noted that the first folded edge 1114, the second folded edge 1154, the third folded edge 1116 and the fourth folded edge 1156 may be formed by a upsetting process, and the upsetting process is known to those skilled in the art, so that the disclosure of the present patent is omitted herein. Of course, it should be understood that if other processes can be used to form the first flange 1114, the second flange 1154, the third flange 1116 and the fourth flange 1156, other processes can be used, and the processing process is not limited in this embodiment.

Referring to fig. 2-4, in an embodiment, the cylindrical battery 110 further includes an explosion-proof ball 118 and a positive electrode convex cap 119, a through hole 1131 disposed along the first direction is disposed on the positive electrode cap 113, the explosion-proof ball 118 is blocked on a side of the through hole 1131 facing away from the electrode group 112, and the explosion-proof ball 118 is sandwiched between the positive electrode convex cap 119 and the positive electrode cap 113. When the internal expansion pressure of the cylindrical battery 110 is high to a certain extent, the explosion-proof ball 118 is jacked up, so that the gas is discharged, and the safety protection function is achieved.

The utility model also provides an energy storage system, as shown in fig. 5 and 6, which comprises a battery pack 100 and a water cooling device. The battery pack 100 includes a plurality of cylindrical batteries 110 as shown in the above embodiments, and the water cooling device includes a water cooling pipe 210 for flowing a water cooling solution, and the water cooling pipe 210 is disposed through a second straight cylindrical steel shell 115 of the cylindrical batteries 110.

Specifically, in the prior art, when it is desired to utilize the water cooling mode to dissipate heat from the battery pack 100, the water cooling pipe 210 can only be disposed at the outer side of the battery pack 100, and the outer side surface of the cylindrical battery 110 is partially attached to the water cooling pipe 210, so as to exchange heat with the water cooling solution in the water cooling pipe 210, while the water cooling pipe 210 of the present embodiment can be disposed inside the cylindrical battery 110 in a penetrating manner, so that the heat dissipation effect is better.

It should be noted that, the larger the size of the cylindrical battery 110, the larger the heat dissipation requirement, and if the heat dissipation capability of the cylindrical battery 110 cannot be improved, the larger the cylindrical battery 110 will be affected. Since the temperature of the cylindrical battery 110 can be better controlled by implementing the present embodiment, the cylindrical battery 110 can be made larger.

Referring to fig. 6, the water cooling apparatus further includes a heat dissipating block 220, a pump body 230, and heat dissipating fins 240, as an example. The heat dissipation block 220 is internally provided with a channel for supplying cold solution to flow, one end of the water cooling pipeline 210 is communicated with one end of the channel, the other end of the water cooling pipeline 210 is communicated with the other end of the channel through the pump body 230, and the pump body 230 can provide power for the cold solution so that the cold solution flows at the positions of the water cooling pipeline 210 and the channel. The heat dissipation fins 240 are disposed on the heat dissipation block 220, so that the heat dissipation fins 240 can be utilized to dissipate heat of the heat dissipation block 220, thereby reducing the temperature of the water-cooling solution flowing through the channel, and enabling the water-cooling solution to circulate to the cylindrical battery 110 for cooling.

Referring to fig. 6, an exemplary embodiment of the present utility model is shown, in which a fan 250 is further installed on a side of the heat dissipation fins 240 facing away from the heat dissipation block 220, the fan 250 can assist the heat dissipation of the heat dissipation fins 240, and the heat dissipation efficiency of the heat dissipation fins 240 is high only when the heat is dissipated into the air more quickly, and the fan 250 can accelerate the air flow near the heat dissipation fins 240, so that the heat dissipation fins 240 can dissipate the heat into the air more quickly, thereby improving the heat dissipation efficiency. In addition, the heat dissipation fan 250 can also help the heat dissipation fins 240 keep clean, preventing dust from accumulating on the fins to affect the heat dissipation effect of the heat dissipation fins 240.

Illustratively, a thermally conductive silicone is disposed between the heat slug 220 and the heat fins 240. Even though the surfaces of the heat dissipating block 220 and the heat dissipating fins 240 look smooth, there are actually minute gaps between the heat dissipating block 220 and the heat dissipating fins 240, which may cause uneven heat transfer, thereby affecting the heat dissipating effect, and after the heat conducting silicone grease is disposed between the heat dissipating block 220 and the heat dissipating fins 240, the heat conducting silicone grease may fill the minute gaps, so that the heat dissipating block 220 may better contact the heat dissipating fins 240, thereby improving the heat transfer efficiency.

It should be understood that the foregoing embodiments are merely illustrative of the technical solutions of the present utility model, and not limiting thereof, and that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art; all such modifications and substitutions are intended to be included within the scope of this disclosure as defined in the following claims.

Claims (10)

1. A cylindrical battery, comprising:

the first cylinder type steel shell extends along a first direction, and both ends of the first cylinder type steel shell are provided with first openings;

the pole group is arranged in the first straight cylinder steel shell;

the positive electrode cap is arranged on one side of the electrode group in the first direction and is electrically connected with the positive electrode plate of the electrode group;

the negative electrode cap is arranged on one side of the electrode group, which is far away from the positive electrode cap, and is electrically connected with the negative electrode plate of the electrode group.

2. The cylindrical battery of claim 1, further comprising a second straight cylindrical steel shell extending in the first direction, wherein both ends of the second straight cylindrical steel shell have second openings, wherein the second straight cylindrical steel shell is installed in the first straight cylindrical steel shell, and wherein the pole group, the positive pole cap, and the negative pole cap are installed between the first straight cylindrical steel shell and the second straight cylindrical steel shell.

3. The cylindrical battery of claim 2, further comprising a first insulating structure and a second insulating structure; the first insulation structure is arranged between the positive electrode cap and the first straight cylinder steel shell and between the positive electrode cap and the second straight cylinder steel shell; the second insulation structure is arranged between the negative electrode cap and the first straight cylinder steel shell, and between the negative electrode cap and the second straight cylinder steel shell.

4. The cylindrical battery of claim 3, wherein the first insulation structure comprises a first outer ring insulation sleeve and a first inner ring insulation sleeve, the first outer ring insulation sleeve is sleeved on the outer ring of the positive cap, and the first inner ring insulation sleeve is sleeved on the inner ring of the positive cap.

5. The cylindrical battery of claim 3, wherein the second insulating structure comprises a second outer ring insulating sleeve and a second inner ring insulating sleeve, the second outer ring insulating sleeve being disposed over the outer ring of the negative cap, the second inner ring insulating sleeve being disposed over the inner ring of the negative cap.

6. The cylindrical battery according to claim 2, wherein the first cylindrical steel shell is provided with two first protruding portions arranged towards the second cylindrical steel shell, the two first protruding portions are arranged at intervals in the first direction, the second cylindrical steel shell is provided with two second protruding portions, the two second protruding portions are opposite to the two first protruding portions respectively, and the polar group is limited in a first installation space defined by the two first protruding portions and the two second protruding portions.

7. The cylindrical battery according to claim 6, wherein one end of the first straight cylindrical steel shell is provided with a first flange portion bent toward the second straight cylindrical steel shell, one end of the second straight cylindrical steel shell is provided with a second flange portion arranged opposite to the first flange portion, the second flange portion, and the first and second protruding portions adjacent to the first flange portion and the second flange portion together define a second installation space, and the positive electrode cap is limited in the second installation space.

8. The cylindrical battery according to claim 6, wherein one end of the first straight cylindrical steel shell is provided with a third folded edge portion bent toward the second straight cylindrical steel shell, one end of the second straight cylindrical steel shell is provided with a fourth folded edge portion arranged opposite to the third folded edge portion, and the third folded edge portion, the fourth folded edge portion, the first protruding portion and the second protruding portion adjacent to the third folded edge portion and the fourth folded edge portion together define a third installation space, and the negative electrode cap is limited in the third installation space.

9. The cylindrical battery according to any one of claims 1 to 6, further comprising an explosion-proof ball and a positive electrode convex cap, wherein a through hole arranged along a first direction is formed in the positive electrode cap, the explosion-proof ball is blocked on one side of the through hole facing away from the electrode group, and the explosion-proof ball is clamped between the positive electrode convex cap and the positive electrode cap.

10. An energy storage system comprising a battery pack and a water cooling device, wherein the battery pack comprises a plurality of cylindrical batteries according to any one of claims 2-9, the water cooling device comprises a water cooling pipeline for flowing a water cooling solution, and the water cooling pipeline penetrates through a second straight cylinder steel shell of the cylindrical batteries.