Battery having positive temperature coefficient element
View Patent ↗A highly reliable cylindrical primary battery is provided where the surface temperature of a body portion of which at the time of a short circuit is controlled to be low. The heat conductivity λ (W/m·K) of a resin sealing body of a sealing assembly having a PTC element and the amount of heat generation Q (W) in the PTC element at the time of tripping are set so that the relational expressions of: 0.12≦λ≦0.27; (1) 1.0≦Q≦1.5; and (2) Q ≦−3.33λ+1.9 are met. (3)
1. An electrochemical device comprising:
a case;
a power generation element included in said case; and
a resin sealing assembly including an external terminal plate, a communication plate electrically connected to said power generation element, a positive temperature coefficient (PTC) element placed between said external terminal plate and said communication plate, an electrode current collector electrically connected to said external terminal plate, and a sealing body made of resin, and sealing an opening of said case;
wherein said resin sealing body comprises polypropylene; and
wherein relational expressions (1) to (3) are satisfied where the heat conductivity of said resin sealing body is λ (W/m·K) and an amount of heat generation in said PTC element at a time of tripping is Q (W):
0.12≦λ≦0.27; (1)
1.0≦Q≦1.5; and (2)
Q≦− 3.33λ+1.9. (3)
2. The electrochemical device in accordance with claim 1 , wherein 0.12≦λ≦0.19 and 1.0≦Q≦1.25.
3. A cylindrical primary battery comprising:
a bottomed cylindrical battery case;
a power generation element included in said battery case; and
a resin sealing assembly including an external terminal plate, a communication plate electrically connected to said power generation element, a positive temperature coefficient (PTC) element placed between said external terminal plate and said communication plate, a collector electrically connected to said external terminal plate, and a sealing body made of resin, and sealing an opening of said battery case;
wherein said resin sealing body comprises polypropylene; and
wherein relational expressions (1) to (3) are satisfied where the heat conductivity of said resin sealing body is λ (W/m·K) and an amount of heat generation in said PTC element at a time of tripping is Q (W):
0.12≦λ≦0.27; (1)
1.0≦Q≦1.5; and (2)
Q≦− 3.33λ+1.9. (3)
4. The cylindrical primary battery in accordance with claim 3 , wherein 0.12≦λ≦0.19 and 1.0≦Q≦1.25.
5. A cylindrical primary AA-size battery comprising:
a bottomed cylindrical battery case;
a power generation element included in said battery case; and
a resin sealing assembly including an external terminal plate, a communication plate electrically connected to said power generation element, a PTC positive temperature coefficient element placed between said external terminal plate and said communication plate, a electrode current collector electrically connected to said external terminal plate, and a sealing body made of resin, and sealing an opening of said battery case;
wherein said resin sealing body comprises of polypropylene; and
wherein relational expressions (1) to (3) are satisfied where the heat conductivity of said resin sealing body is λ (W/m·K) and an amount of heat generation in said PTC element at a time of tripping is Q (W):
0.12≦λ≦0.27; (1)
1.0≦Q≦1.5; and (2)
Q≦− 3.33λ+1.9. (3)
6. The cylindrical primary AA-size battery in accordance with claim 5 , wherein said PTC element is ring-shaped.
7. The cylindrical primary AA-size battery in accordance with claim 6 , wherein said PTC element has an area of 45 mm 2 to 71 mm 2 when viewed in plan view.
8. The cylindrical primary AA-size battery in accordance with claim 5 , wherein 0.12≦λ≦0.19 and 1.0≦Q≦1.25.