Battery and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery and a battery pack. The shell is internally provided with a hollow cavity, the pole group is arranged corresponding to the hollow cavity, a first opening is formed in the first end, in the height direction, of the shell, two opposite first inner walls, in the length direction, of the shell protrude inwards to form first limiting parts, and the first limiting parts and the end face of the pole group are oppositely arranged in a spaced mode in the height direction; the top cover assembly is arranged corresponding to the first opening, the top cover assembly comprises an anti-explosion valve, and the top cover assembly abuts against the end face of the pole group. When the pole group loses the limiting effect of the top cover assembly, if the pole group moves towards the anti-explosion valve, the pole group is limited by the first limiting part along the two sides of the length direction, so that the end surface of the pole group is prevented from being in contact with the anti-explosion valve to cause blockage of the anti-explosion valve, gas in the battery is smoothly discharged from the anti-explosion valve, and the safety of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to batteries and battery packs. Background Art

[0002] As battery technology becomes increasingly mature, batteries are widely used as power sources in electric vehicles and energy storage fields, and the requirements for battery performance and safety are increasing. In traditional batteries, the cover plate and the shell are welded and sealed to encapsulate the electrode group inside, and the electrode group is connected to the pole on the cover plate through a connecting piece. The lower plastic in the cover plate presses against the electrode group to limit the electrode group. When the battery has thermal runaway, the temperature inside the battery is too high, and the excessive gas production inside the battery reaches the triggering condition, the explosion-proof valve opens, and the gas inside the battery is quickly discharged. However, the lower plastic is usually made of PP material, which will cause the lower plastic to melt completely and lose its limiting effect on the electrode group. At this time, whether the battery is used in an upright or inverted state, there is a risk that the electrode group will move and block the explosion-proof valve, thereby accelerating the battery runaway and increasing safety risks. Utility Model Content

[0003] In view of this, the utility model provides a battery and a battery pack to solve the problem that when the battery has thermal runaway, the lower plastic is completely melted, the limiting effect on the electrode group is lost, and there is a risk of the electrode group moving and blocking the explosion-proof valve, thereby accelerating the battery runaway and increasing the safety risk.

[0004] In a first aspect, the utility model provides a battery, comprising: a pole group; a shell having a hollow cavity inside, the pole group being arranged corresponding to the hollow cavity, the shell forming a first opening at a first end along a height direction, two first inner walls of the shell opposite to each other along a length direction protruding inwardly to form a first limiting portion, the first limiting portion being arranged at a relative interval to the end face of the pole group along the height direction; a top cover assembly, arranged corresponding to the first opening, the top cover assembly comprising an explosion-proof valve, and the top cover assembly being arranged in contact with the end face of the pole group.

[0005] Beneficial effect: When the electrode group loses the limiting function of the top cover assembly, if the electrode group moves toward the explosion-proof valve, the electrode group is limited by the first limiting portion on both sides along the length direction to prevent the end face of the electrode group from contacting the explosion-proof valve and causing the explosion-proof valve to be blocked, so that the gas in the battery is smoothly discharged from the explosion-proof valve, thereby improving the safety of the battery.

[0006] In an optional embodiment, the pole group is stacked along the width direction, and the first limiting portion extends along the width direction and is arranged corresponding to the pole group along the width direction.

[0007] Beneficial effect: The electrode group is limited along the stacking direction of the electrode group by the first limiting part, so that the first limiting part can limit the positive electrode sheets, diaphragms and negative electrode sheets stacked in the electrode group, ensuring that each layer of positive electrode sheets, diaphragms and negative electrode sheets will not be displaced, further avoiding blockage of the explosion-proof valve.

[0008] In an optional embodiment, along the length direction, the length of the portion of the first limiting portion corresponding to the pole group is f, satisfying 1mm≤f≤5mm; and / or, the distance between the first inner wall and the corresponding side of the pole group is d, satisfying 0.5mm≤d≤3mm.

[0009] Beneficial effects: 1mm≤f≤5mm, while ensuring that the pole group has sufficient limiting length, reduces the difficulty of processing the shell; 0.5mm≤d≤3mm, while ensuring that the pole group can be smoothly installed in the shell, avoids the pole group from shaking in the shell.

[0010] In an optional implementation, along the length direction, the length of the first limiting portion is e, satisfying e≥d+f.

[0011] In an optional embodiment, along the height direction, the distance between the side of the first limiting portion facing the pole group and the end face of the pole group is b, satisfying b≥2mm; and / or, along the height direction, the distance between the side of the first limiting portion facing the pole group and the side of the explosion-proof valve facing the pole group is a, satisfying a≥3mm; and / or, along the height direction, the height of the first limiting portion is c, satisfying 0.5mm≤c≤2mm.

[0012] Beneficial effects: b≥2mm ensures that there is a sufficient distance between the first limiting part and the electrode group, avoiding the first limiting part from contacting the electrode piece in the electrode group and causing a short circuit; a≥3mm ensures that there is sufficient exhaust space between the electrode group and the explosion-proof valve when thermal runaway occurs, so that the gas can be released from the explosion-proof valve in time; 0.5mm≤c≤2mm ensures that the first limiting part has sufficient structural strength to limit the electrode group, while reducing the processing difficulty of the shell and meeting the lightweight requirements of the battery.

[0013] In an optional embodiment, a second opening is formed at a second end of the shell in the height direction, and the battery further includes a bottom plate, which is arranged corresponding to the second opening.

[0014] In an optional embodiment, the base plate includes a guide structure and a connecting structure, and the guide structure and the connecting structure are connected along the height direction. Along the circumference of the base plate, the connecting structure extends from the guide structure, and the guide structure is inserted into the shell through the second opening. The edge of the connecting structure is connected to the second end of the shell to block the second opening.

[0015] Beneficial effect: By setting the guide structure, the cooperation between the bottom plate and the shell is guided and positioned, which facilitates the installation of the bottom plate.

[0016] In an optional embodiment, the distance between the outer periphery of the guide structure and the inner wall of the shell is k, satisfying 0.05mm≤k≤2mm; and / or, along the height direction, the height of the guide structure is x, satisfying 1mm≤x≤3mm; and / or, along the height direction, the height of the connecting structure is h, satisfying 1mm≤h≤3mm.

[0017] Beneficial effects: 0.05mm≤k≤2mm, which enables the guide structure to be smoothly inserted into the shell and improves the positioning accuracy; 1mm≤x≤3mm, which ensures the guiding effect of the guide structure and avoids material waste; 1mm≤h≤3mm, which ensures the connection strength between the connecting structure and the shell and avoids material waste.

[0018] In an optional embodiment, two second inner walls of the shell that are opposite to each other in the width direction protrude inward to form a second limiting portion.

[0019] Beneficial effect: By setting the second limiting part, the limiting effect of the pole group is further enhanced.

[0020] In a second aspect, the utility model also provides a battery pack, comprising the above-mentioned battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A top view of a battery according to an embodiment of the present utility model;

[0023] Figure 2 for Figure 1 Sectional view of AA in the middle;

[0024] Figure 3for Figure 2 Cross-sectional view of the middle BB;

[0025] Figure 4 for Figure 2 Enlarged view of point C in the middle;

[0026] Figure 5 for Figure 2 The enlarged view of point D in the middle;

[0027] Figure 6 This is a schematic diagram of the exploded structure of a battery according to an embodiment of the present utility model;

[0028] Figure 7 for Figure 6 Enlarged view of point E in the middle;

[0029] Figure 8 for Figure 6 Enlarged view of point F in the middle.

[0030] Description of reference numerals:

[0031] 1. Pole group; 2. Shell; 21. First opening; 22. First inner wall; 23. First limit portion; 24. Second opening; 25. Second inner wall; 26. Second limit portion; 3. Top cover assembly; 31. Explosion-proof valve; 32. Lower plastic; 4. Bottom plate; 41. Guide structure; 42. Connection structure. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0033] Combine the following Figures 1 to 8 , describing an embodiment of the utility model.

[0034] According to an embodiment of the utility model, on the one hand, a battery is provided, comprising: a pole group 1, a shell 2 and a top cover assembly 3. The shell 2 has a hollow cavity inside, and the pole group 1 is arranged corresponding to the hollow cavity. The shell 2 forms a first opening 21 at the first end along the height direction, and the top cover assembly 3 is arranged corresponding to the first opening 21. Two first inner walls 22 of the shell 2 opposite to each other along the length direction protrude inward to form a first limiting portion 23, and the first limiting portion 23 is arranged at a relative interval with the end face of the pole group 1 along the height direction. The top cover assembly 3 includes an explosion-proof valve 31, and the top cover assembly 3 is arranged in contact with the end face of the pole group 1.

[0035] When the electrode group 1 loses the limiting effect of the top cover assembly 3, if the electrode group 1 moves toward the explosion-proof valve 31, the electrode group 1 is limited by the first limiting portion 23 on both sides along the length direction to prevent the end face of the electrode group 1 from contacting the explosion-proof valve 31 and causing the explosion-proof valve 31 to be blocked, so that the gas in the battery is smoothly discharged from the explosion-proof valve 31, thereby improving the safety of the battery.

[0036] It is worth mentioning that please refer to Figure 4 The top cover assembly 3 also includes a lower plastic 32, which is disposed in contact with the end surface of the electrode group 1. Under normal circumstances, the lower plastic 32 is used to limit the electrode group 1 in the height direction. However, when the battery has thermal runaway and the lower plastic 32 melts, the top cover assembly 3 cannot limit the electrode group 1 in the height direction. When the electrode group 1 moves toward the explosion-proof valve 31 in the height direction, the first limiting portion 23 is used to limit the electrode group 1.

[0037] It should be noted that the battery can be placed upright or inverted when in use. The upright position means that the explosion-proof valve 31 is located above the electrode group 1, and the inverted position means that the explosion-proof valve 31 is located below the electrode group 1. When the upright battery has thermal runaway, there is a risk that the electrode group 1 is lifted upward by the airflow and blocks the explosion-proof valve 31; when the inverted battery has thermal runaway, the electrode group 1 moves toward the explosion-proof valve 31 under the action of the gravity of the electrode group 1 and blocks the explosion-proof valve 31.

[0038] In one embodiment, Figure 5 and Figure 6 As shown, the electrode group 1 is stacked in the width direction, and the first limiting portion 23 extends in the width direction and is arranged corresponding to the electrode group 1 in the width direction. The electrode group 1 is limited in the stacking direction of the electrode group 1 by the first limiting portion 23, so that the first limiting portion 23 can limit the positive electrode sheets, diaphragms and negative electrode sheets stacked in the electrode group 1, ensuring that each layer of positive electrode sheets, diaphragms and negative electrode sheets will not be displaced, further avoiding blockage of the explosion-proof valve 31.

[0039] In one embodiment, Figure 5 and Figure 6 As shown, two second inner walls 25 of the housing 2 opposite to each other in the width direction protrude inwards to form second limiting portions 26. By providing the second limiting portions 26, the limiting effect of the electrode group 1 is further enhanced.

[0040] It is worth noting that, in the related art, the electrode group 1 is limited only by the second limiting portion 26, and the second limiting portion 26 is extended along the length direction, and the second limiting portion 26 is perpendicular to the stacking direction of the electrode group 1, that is, the second limiting portion 26 can only limit the positive electrode sheets, diaphragms and negative electrode sheets located on both sides of the electrode group 1 along the stacking direction, and cannot limit the positive electrode sheets, diaphragms and negative electrode sheets located in the middle position, which can easily cause the positive electrode sheets, diaphragms and negative electrode sheets stacked in the middle position to be misplaced, and there is still a risk of clogging the explosion-proof valve 31.

[0041] In one embodiment, Figure 5 and Figure 6 As shown, the first limiting portion 23 and the second limiting portion 26 are integrally formed on the inner wall of the shell 2 along the circumference of the shell 2 .

[0042] In one embodiment, Figure 4 As shown, along the length direction, the length of the portion of the first limiting portion 23 corresponding to the pole group 1 is f, satisfying 1mm≤f≤5mm. 1mm≤f≤5mm ensures that the pole group 1 has a sufficient limiting length while reducing the difficulty of processing the housing 2.

[0043] It should be noted that if the value of f is too small, the length of the first limiting portion 23 used to abut and limit the electrode group 1 is too short, and the reliability of limiting the electrode group 1 cannot be guaranteed; if the value of f is too large, the length of the first limiting portion 23 is too long, which is not convenient for the processing and forming of the shell 2.

[0044] It is worth noting that the portion of the first limiting portion 23 corresponding to the electrode group 1 is, that is, the portion that contacts the electrode group 1 when the first limiting portion 23 limits the electrode group 1 .

[0045] In one embodiment, Figure 4 As shown, the distance d between the first inner wall 22 and the corresponding side surface of the pole group 1 satisfies 0.5 mm ≤ d ≤ 3 mm. 0.5 mm ≤ d ≤ 3 mm ensures that the pole group 1 can be smoothly installed in the housing 2 while preventing the pole group 1 from shaking in the housing 2.

[0046] It should be noted that if the value of d is too small, the gap between the pole group 1 and the first inner wall 22 is too small when the pole group 1 is inserted into the shell 2, which makes it inconvenient for the pole group 1 to enter the shell and easily causes scratches on the pole group 1; if the value of d is too large, the gap between the pole group 1 and the first inner wall 22 is too large after the pole group 1 enters the shell, which easily causes the pole group 1 to shake in the shell 2 and reduces the space utilization rate of the shell 2.

[0047] In one embodiment, Figure 4 As shown, along the length direction, the length of the first limiting portion 23 is e, satisfying e≥d+f.

[0048] In one embodiment, Figure 4 As shown, along the height direction, the distance between the side of the first limit portion 23 facing the pole group 1 and the end face of the pole group 1 is b, and b≥2mm is satisfied. Making b≥2mm ensures that there is a sufficient distance between the first limit portion 23 and the pole group 1 to avoid the first limit portion 23 contacting the pole piece in the pole group 1 and causing a short circuit.

[0049] It is worth noting that the distance b is the distance between the surface of the first limiting portion 23 facing the electrode group 1 and the surface where the lower plastic 32 and the end surface of the electrode group 1 abut against each other.

[0050] In one embodiment, Figure 4 As shown, along the height direction, the distance between the side of the first limiter 23 facing the pole group 1 and the side of the explosion-proof valve 31 facing the pole group 1 is a, and a≥3mm is satisfied. When a≥3mm, when thermal runaway occurs, it is ensured that there is sufficient exhaust space between the pole group 1 and the explosion-proof valve 31, so that the gas can be released from the explosion-proof valve 31 in time.

[0051] It is worth noting that when thermal runaway occurs, the first limiting portion 23 can support an exhaust space with a height of at least 3 mm to facilitate rapid exhaust.

[0052] In one embodiment, Figure 4 As shown, along the height direction, the height of the first limit portion 23 is c, which satisfies 0.5mm≤c≤2mm. 0.5mm≤c≤2mm ensures that the first limit portion 23 has sufficient structural strength to limit the electrode group 1, while reducing the processing difficulty of the shell 2 and meeting the lightweight requirements of the battery.

[0053] It should be noted that if the value of c is too small, the first limit portion 23 is too thin, and when the first limit portion 23 abuts against the pole group 1 to limit the position, the first limit portion 23 is easy to deform or even break, and the reliability of limiting the pole group 1 cannot be guaranteed; if the value of c is too large, the first limit portion 23 is too thick, which is not convenient for processing and forming the shell 2, and the required materials increase, resulting in increased production costs and an increase in the weight of the shell 2.

[0054] In one embodiment, Figure 2 , Figure 3 and Figure 6 As shown, a second opening 24 is formed at the second end of the housing 2 in the height direction, and the battery further includes a bottom plate 4 , which is arranged corresponding to the second opening 24 .

[0055] It is worth noting that when assembling the battery of this embodiment, the electrode group 1 is first loaded into the shell 2 through the second opening 24, and then the bottom plate 4 is covered on the second opening 24, and the bottom plate 4 and the shell 2 are welded and sealed, and then the pole ear of the electrode group 1 and the top cover assembly 3 are welded to achieve electrical connection, and finally the top cover assembly 3 and the shell 2 are welded and sealed to block the first opening 21.

[0056] In one embodiment, Figure 5 and Figure 8 As shown, the bottom plate 4 includes a guide structure 41 and a connection structure 42, the guide structure 41 and the connection structure 42 are connected and arranged along the height direction, and the connection structure 42 is extended from the guide structure 41 along the circumference of the bottom plate 4, and the guide structure 41 is inserted into the shell 2 through the second opening 24, and the edge of the connection structure 42 is connected and arranged with the second end of the shell 2 to block the second opening 24. By setting the guide structure 41, the cooperation between the bottom plate 4 and the shell 2 is guided and positioned, which facilitates the installation of the bottom plate 4.

[0057] It is worth noting that the guide structure 41 is inserted into the shell 2, and the connection structure 42 is located outside the shell 2. The connection structure 42 overlaps the shell 2 along the wall thickness of the shell 2 by extending the guide structure 41 circumferentially, and then is connected by welding.

[0058] In one embodiment, Figure 5 As shown, the distance between the outer periphery of the guide structure 41 and the inner wall of the housing 2 is k, which satisfies 0.05 mm ≤ k ≤ 2 mm. When 0.05 mm ≤ k ≤ 2 mm, the guide structure 41 can be smoothly inserted into the housing 2 while improving the positioning accuracy.

[0059] It should be noted that if the value of k is too small, the gap between the guide structure 41 and the inner wall of the shell 2 is too small, making it inconvenient to insert the guide structure 41 into the shell 2; if the value of k is too large, the gap between the guide structure 41 and the inner wall of the shell 2 is too large, and the guide structure 41 loses its guiding and positioning functions, making it impossible to ensure the accuracy of the installation of the base plate 4.

[0060] In one embodiment, Figure 5 As shown, along the height direction, the height of the guide structure 41 is x, which satisfies 1mm≤x≤3mm. 1mm≤x≤3mm can ensure the guiding effect of the guide structure 41 while avoiding material waste.

[0061] It should be noted that if the value of x is too small, the guide structure 41 is too short and cannot play a guiding role; if the value of x is too large, the guide structure 41 is too long, too much material is required for the guide structure 41, and the guide structure 41 occupies too much internal space of the shell 2, reducing the space utilization rate of the shell 2.

[0062] In one embodiment, Figure 5 As shown, along the height direction, the height of the connection structure 42 is h, which satisfies 1mm≤h≤3mm. 1mm≤h≤3mm ensures the connection strength between the connection structure 42 and the housing 2 while avoiding material waste.

[0063] It should be noted that if the value of h is too small, the connection structure 42 is too thin, and it is difficult to ensure the welding strength between the connection structure 42 and the shell 2, which affects the assembly quality and reliability of the battery; if the value of h is too large, the connection structure 42 is too thick, and too much material is required for the connection structure 42, resulting in waste.

[0064] When the battery of this embodiment is used upright, if thermal runaway occurs in the battery, the temperature inside the battery is too high, causing the lower plastic 32 to completely melt, and the excessive gas production inside the battery reaches the trigger condition to open the explosion-proof valve 31, and the electrode group 1 is pushed upward by the airflow. Under the action of the first limiting portion 23, the electrode group 1 is abutted and limited, leaving an exhaust space between the end face of the electrode group 1 and the explosion-proof valve 31, and the gas inside the battery is quickly discharged.

[0065] When the battery of this embodiment is used upside down, if thermal runaway occurs in the battery, the temperature inside the battery is too high, causing the lower plastic 32 to completely melt, and the excessive gas production inside the battery reaches the trigger condition to open the explosion-proof valve 31, the electrode group 1 loses the support of the lower plastic 32, and the electrode group 1 falls under its own gravity. Under the action of the first limiting portion 23, the electrode group 1 is abutted and limited, so that an exhaust space is left between the end face of the electrode group 1 and the explosion-proof valve 31, and the gas inside the battery is quickly discharged.

[0066] According to an embodiment of the present invention, on the other hand, a battery pack is provided, comprising the above-mentioned battery.

[0067] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: include: Pole group; A shell having a hollow cavity inside, the pole group is arranged corresponding to the hollow cavity, the first end of the shell along the height direction forms a first opening, two first inner walls of the shell opposite to each other along the length direction protrude inwardly to form a first limiting portion, and the first limiting portion is arranged relative to the end surface of the pole group along the height direction and spaced apart; A top cover assembly is arranged corresponding to the first opening, the top cover assembly includes an explosion-proof valve, and the top cover assembly is arranged in contact with the end surface of the pole group.

2. The battery according to claim 1, characterized in that The pole group is stacked along the width direction, and the first limiting portion extends along the width direction and is arranged corresponding to the pole group along the width direction.

3. The battery according to claim 1 or 2, characterized in that: Along the length direction, the length of the portion of the first limiting portion corresponding to the pole group is f, satisfying 1mm≤f≤5mm; and / or, The distance between the first inner wall and the corresponding side surface of the pole group is d, which satisfies 0.5 mm≤d≤3 mm.

4. The battery according to claim 3, characterized in that Along the length direction, the length of the first limiting portion is e, satisfying e≥d+f.

5. The battery according to claim 1 or 2, characterized in that: In the height direction, the distance between a side of the first limiting portion facing the pole group and an end face of the pole group is b, and b≥2mm; and / or, In the height direction, the distance between a side of the first limit portion facing the pole group and a side of the explosion-proof valve facing the pole group is a, and a≥3mm is satisfied; and / or, Along the height direction, the height of the first limiting portion is c, satisfying 0.5mm≤c≤2mm.

6. The battery according to claim 1 or 2, characterized in that: A second opening is formed at a second end of the shell in the height direction, and the battery further includes a bottom plate, which is arranged corresponding to the second opening.

7. The battery according to claim 6, characterized in that The base plate includes a guide structure and a connecting structure, and the guide structure and the connecting structure are connected along the height direction. Along the circumference of the base plate, the connecting structure extends from the guide structure, and the guide structure is inserted into the shell through the second opening. The edge of the connecting structure is connected to the second end of the shell to block the second opening.

8. The battery according to claim 7, characterized in that The distance between the outer periphery of the guide structure and the inner wall of the housing is k, which satisfies 0.05 mm ≤ k ≤ 2 mm; and / or, In the height direction, the height of the guide structure is x, which satisfies 1mm≤x≤3mm; and / or, Along the height direction, the height of the connection structure is h, satisfying 1mm≤h≤3mm.

9. The battery according to claim 1 or 2, characterized in that: Two second inner walls of the shell that are opposite to each other in the width direction protrude inwardly to form a second limiting portion.

10. A battery pack, characterized in that: A battery comprising the battery according to any one of claims 1 to 9.

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